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Sample records for rotary instrument comparative

  1. "Dentinal microcracks after root canal preparation" a comparative evaluation with hand, rotary and reciprocating instrumentation.

    Science.gov (United States)

    Priya, N Tulasi; Chandrasekhar, Veeramachaneni; Anita, S; Tummala, Muralidhar; Raj, T B Phanindhar; Badami, Vijetha; Kumar, Pradeep; Soujanya, E

    2014-12-01

    The purpose of this study was to compare the incidence of dentinal micro cracks after instrumentation with various types of NiTi files in rotary and reciprocating motion. One hundred human extracted mandibular central incisors were taken and divided into 10 groups (n=10 teeth per group). Group 1- No preparation, Group 2 - Hand instrumentation, Groups 3,4 - ProTaper files in rotary and reciprocating motion, Groups 5,6 - ProTaper Next files in rotary and reciprocating motion, Groups 7,8 - Oneshape files in rotary and reciprocating motion, Groups 9,10 - Reciproc files in rotary and reciprocating motion. Specimens were sectioned horizontally at 3,6 and 9 mm from the apex and dentinal micro cracks were observed under a stereomicroscope. There was a statistically significant difference between the groups (pProtaper Next - Rot, Protaper Next - Rec, Reciproc - Rec); (ProTaper - Rot, ProTaper - Rec, Oneshape - Rot), (Oneshape - Rot, Reciproc - Rot), (One shape Reciproc, Reciproc - Rec); (p >.05). Least cracks were seen in canals instrumented with Pro Taper Next files both in rotary and reciprocating motion. Full sequence rotary systems showed less cracks than single file systems and full sequence rotary systems showed less cracks in reciprocating motion than in rotary motion.

  2. In vitro comparative study of manual and mechanical rotary instrumentation of root canals using computed tomography.

    Science.gov (United States)

    Limongi, Orlando; de Albuquerque, Diana Santana; Baratto Filho, Flares; Vanni, José Roberto; de Oliveira, Elias P Motcy; Barletta, Fernando Branco

    2007-01-01

    This in vitro study compared, using computed tomography (CT), the amount of dentin removed from root canal walls by manual and mechanical rotary instrumentation techniques. Forty mandibular incisors with dental crown and a single canal were selected. The teeth were randomly assigned to two groups, according to the technique used for root canal preparation: Group I - manual instrumentation with stainless steel files; Group II - mechanical instrumentation with RaCe rotary nickel-titanium instruments. In each tooth, root dentin thickness of the buccal, lingual, mesial and distal surfaces in the apical, middle and cervical thirds of the canal was measured (in mm) using a multislice CT scanner (Siemens Emotion, Duo). Data were stored in the SPSS v. 11.5 and SigmaPlot 2001 v. 7.101 softwares. After crown opening, working length was determined, root canals were instrumented and new CT scans were taken for assessment of root dentin thickness. Pre- and post-instrumentation data were compared and analyzed statistically by ANOVA and Tukey's post-hoc test for significant differences (p=0.05). Based on the findings of this study, it may be concluded that regarding dentin removal from root canal walls during instrumentation, neither of the techniques can be considered more effective than the other.

  3. Comparative Study of Three Rotary Instruments for root canal Preparation using Computed Tomography

    International Nuclear Information System (INIS)

    Mohamed, A.M.E.

    2015-01-01

    instruments undergo fracture without warning that is difficult, if not impossible, to predict clinically. Recently, an innovative concept of mechanical root canal preparation, the Anatomic Endodontic Technology (AET) has been introduced. AET was specifically designed to maintain the natural shape of the root canal during preparation. The AET technique was performed with stainless steel instruments used in a 30°reciprocating side-to-side and up-and-down motion. These instruments are stiffer than nickel-titanium rotary instruments and can be easier and with less risk forced towards the root canal walls and the polar recesses during the side-to-side lifting motion. The use of stainless steel instruments in this motion was probably more efficient in following the natural shape of canals and in removing tooth structure. The manufacturer claims that this system is intended to minimize the number of steps and instruments required for effective preparation of root canals. The reciprocating motion of the endodontic instrument has been shown to decrease the impact of cyclic fatigue compared with rotational motion. A reciprocating instrumentation system, (SafeSiders) introduced by Essential Dental Systems was introduced for preparing curved canal to overcome the problem of file separation. It contains a series of non-circular instruments with D-shaped cross section, cutting tip, a patented non-interrupted flat-sided architecture.

  4. Comparative study of six rotary nickel-titanium systems and hand instrumentation for root canal preparation.

    Science.gov (United States)

    Guelzow, A; Stamm, O; Martus, P; Kielbassa, A M

    2005-10-01

    To compare ex vivo various parameters of root canal preparation using a manual technique and six different rotary nickel-titanium (Ni-Ti) instruments (FlexMaster, System GT, HERO 642, K3, ProTaper, and RaCe). A total of 147 extracted mandibular molars were divided into seven groups (n = 21) with equal mean mesio-buccal root canal curvatures (up to 70 degrees), and embedded in a muffle system. All root canals were prepared to size 30 using a crown-down preparation technique for the rotary nickel-titanium instruments and a standardized preparation (using reamers and Hedströem files) for the manual technique. Length modifications and straightening were determined by standardized radiography and a computer-aided difference measurement for every instrument system. Post-operative cross-sections were evaluated by light-microscopic investigation and photographic documentation. Procedural errors, working time and time for instrumentation were recorded. The data were analysed statistically using the Kruskal-Wallis test and the Mann-Whitney U-test. No significant differences were detected between the rotary Ni-Ti instruments for alteration of working length. All Ni-Ti systems maintained the original curvature well, with minor mean degrees of straightening ranging from 0.45 degrees (System GT) to 1.17 degrees (ProTaper). ProTaper had the lowest numbers of irregular post-operative root canal diameters; the results were comparable between the other systems. Instrument fractures occurred with ProTaper in three root canals, whilst preparation with System GT, HERO 642, K3 and the manual technique resulted in one fracture each. Ni-Ti instruments prepared canals more rapidly than the manual technique. The shortest time for instrumentation was achieved with System GT (11.7 s). Under the conditions of this ex vivo study all Ni-Ti systems maintained the canal curvature, were associated with few instrument fractures and were more rapid than a standardized manual technique. Pro

  5. Cyclic Fatigue of Different Nickel-Titanium Rotary Instruments: A Comparative Study

    OpenAIRE

    Testarelli, L.; Grande, N.M; Plotino, G; Lendini, M; Pongione, G; Paolis, G. De; Rizzo, F; Milana, V; Gambarini, G

    2009-01-01

    Since the introduction of nickel-titanium alloy to endodontics, there have been many changes in instrument design, but no significant improvements in the raw material properties, or enhancements in the manufacturing process. Recently, a new method to produce nickel-titanium rotary (NTR) instruments has been developed, in an attempt to obtain instruments that are more flexible and resistant to fatigue. NTR instruments produced using the process of twisting (TF, SybronEndo, Orange, CA) were com...

  6. Torsional resistance of XP-endo Shaper at body temperature compared with several nickel-titanium rotary instruments.

    Science.gov (United States)

    Elnaghy, A M; Elsaka, S E

    2018-05-01

    To compare the torsional resistance of XP-endo Shaper (XPS; size 30, .01 taper, FKG Dentaire, La Chaux-de-Fonds, Switzerland) instruments at body temperature with TRUShape (TRS; size 30, .06 taper, Dentsply Tulsa Dental Specialties, Tulsa, OK, USA), ProFile Vortex (PV; size 30, .04 taper, Dentsply Tulsa Dental Specialties) and FlexMaster (FM; size 30, .04 taper, VDW GmbH, Munich, Germany) nickel-titanium rotary instruments. A metal block with a square-shaped mould (5 mm × 5 mm × 5 mm) was positioned inside a glass container. Five millimetres of the tip of each instrument was held inside the metal block by filling the mould with a resin composite. The instruments were tested for torsional resistance in saline solution at 37 °C. Data were analysed using one-way analysis of variance (anova) and Tukey post hoc tests. The significance level was set at P instruments tested (P instruments (P = 0.211). The ranking for torsional resistance values was: FM > PV > TRS > XPS. FlexMaster and ProFile Vortex instruments were more resistant to torsional stress compared with TRUShape and XP-endo Shaper instruments. The manufacturing process used to produce XP-endo Shaper instruments did not enhance their resistance to torsional stress as compared with the other instruments. © 2017 International Endodontic Journal. Published by John Wiley & Sons Ltd.

  7. Histological analysis of cleaning efficacy of hand and rotary instruments in the apical third of the root canal: A comparative study.

    Science.gov (United States)

    Arya, Ashtha; Bali, Dildeep; Grewal, Mandeep S

    2011-07-01

    To compare the cleaning efficiency of manual and rotary instrumentation in the apical third of the root canal system. In group 1 (n=10), instrumentation was performed with stainless steel K-file; in group 2 (n=10), it was done with hand ProTaper files; and in group 3 (n=10), instrumentation was done with ProTaper rotary. Distilled water was used for irrigation. The apical third was sectioned transversally and histologically processed. The cross sections were examined under optic microscope and debris was measured using Motic software. Instrumentation with stainless steel K-files showed minimum amount of debris, followed by ProTaper hand files, and rotary ProTaper files were least effective with maximum amount of debris; however, there were no significant differences between the three experimental groups. Both the manual and rotary instrumentation are relatively efficient in cleaning the apical third of the root canal system and the choice between manual and rotary instrumentation should depend on case to case basis.

  8. Increase in Periodontal Interleukin-1β Gene Expression Following Osseous Resective Surgery Using Conventional Rotary Instruments Compared with Piezosurgery: A Split-Mouth Randomized Clinical Trial.

    Science.gov (United States)

    Aimetti, Mario; Ferrarotti, Francesco; Bergandi, Loredana; Saksing, Laura; Parducci, Francesca; Romano, Federica

    2016-01-01

    The purpose of this study was to evaluate the early inflammatory response following osseous resective surgery (ORS) with Piezosurgery compared to commonly used diamond burs. A sample was selected of 24 bilateral posterior sextants requiring ORS in 12 chronic periodontitis patients in a split-mouth design. In 12 sextants, bone recontouring was performed using a piezoelectric device. In the contralateral sextants, rotary instruments were used. Sextants treated with Piezosurgery obtained similar 12-month clinical results but lower postsurgical gene expression of interleukin-1β (IL-1β), a well-known proinflammatory cytokine, and lower patient morbidity compared with sextants treated with rotary instruments. In spite of the longer surgical time, the use of Piezosurgery for ORS seems to promote more favorable wound healing compared with rotary instruments, as the lower pain and the low levels of IL-1β mRNA at the surgical sites suggest a milder underlying inflammatory response.

  9. Rotary mode system initial instrument calibration

    International Nuclear Information System (INIS)

    Johns, B.R.

    1994-01-01

    The attached report contains the vendor calibration procedures used for the initial instrument calibration of the rotary core sampling equipment. The procedures are from approved vendor information files

  10. Comparative study of 6 rotary nickel-titanium systems and hand instrumentation for root canal preparation in severely curved root canals of extracted teeth.

    Science.gov (United States)

    Celik, Davut; Taşdemir, Tamer; Er, Kürşat

    2013-02-01

    Some improvements have been developed with new generations of nickel-titanium (NiTi) rotary instruments that led to their successful and extensive application in clinical practice. The purpose of this in vitro study was to compare the root canal preparations performed by using GT Series X and Twisted File systems produced by innovative manufacturing process with Revo-S, RaCe, Mtwo, and ProTaper Universal systems manufactured directly from conventional nitinol and with stainless steel K-Flexofile instruments. The mesiobuccal root canals of 140 maxillary first permanent molars that had between 30°-40° curvature angle and 4- to 9-mm curvature radius of the root canal were used. After root canal preparations made by using GT Series X, Twisted File, Revo-S, RaCe, Mtwo, and ProTaper Universal NiTi rotary systems and stainless steel K-Flexofile instruments, transportation occurred in the root canal, and alteration of working length (WL) was assessed by using a modified double-digital radiographic technique. The data were compared by the post hoc Tukey honestly significant difference test. NiTi rotary systems caused less canal transportation and alteration of WL than K-Flexofile instruments (P .05) except 2.5 mm from the WL. At this level ProTaper Universal system caused significant canal transportation (P ProTaper Universal rotary systems manufactured by traditional methods. Copyright © 2013 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  11. Comparative evaluation of apically extruded debris during root canal instrumentation using two Ni-Ti single file rotary systems: An in vitro study.

    Science.gov (United States)

    Singbal, Kiran; Jain, Disha; Raja, Kranthi; Hoe, Tan Ming

    2017-01-01

    Apical extrusion of debris during instrumentation is detrimental to the patient. The aim of this study was to evaluate the apical extrusion of debris during root canal instrumentation using two single file rotary Ni-Ti systems. Thirty freshly extracted mandibular premolars with straight roots were sterilized and divided into two groups instrumented using: One Shape rotary Ni-Ti system with Endoflare orifice shaper (Group 1) and Neo-Niti rotary Ni-Ti system with C1 orifice shaper (Group 2). Preweighed Eppendorf tubes fitted for each tooth before instrumentation. During instrumentation, 1 mL of distilled water with a 30-gauge needle was used to irrigate after every instrument. Tips of the tooth were irrigated with 2 ml distilled water after removal from Eppendorf tubes. The total volume of irrigant in each group was the same 8 ml. All tubes were incubated at 68°C for 15 days and subsequently weighed. The difference between pre- and post-debris weights was calculated, and statistical analysis was performed using independent t -test and level of significance was set at 0.05. The difference between pre- and post-weights was significantly greater for the One Shape system. The Neolix Niti single file was associated with less extrusion compared to One Shape single file system.

  12. A comparative evaluation of cleaning efficacy (debris and smear layer removal) of hand and two NiTi rotary instrumentation systems (K3 and ProTaper): a SEM study.

    Science.gov (United States)

    Reddy, K Balakoti; Dash, Shreemoy; Kallepalli, Sowmya; Vallikanthan, Sangeetha; Chakrapani, N; Kalepu, Vamsi

    2013-11-01

    The present study was conducted to compare the cleaning efficacy (debris and smear layer removal) of hand and two NiTi rotary instrumentation systems (K3 and ProTaper). Sixty single rooted human maxillary anterior teeth decoronated at the cementoenamel junction were used. All the specimens were divided into four groups of 15 teeth each, group I--ProTaper rotary instrumentation done, group II--K3 rotary instrumentation done, group III--Stainless steel K-file instrumentation done, group IV--root canal irrigation without instrumentation. Root canal preparation was done in a crown down manner and 3% sodium hypochlorite was used as irrigant after each file followed by final rinse with 5 ml of 17% EDTA solution, then specimens were scanning electron microscopic (SEM) examination. Statistical analysis was done using one-way ANOVA followed by post hoc Tukey's HSD test. Group I showed highly statistical significant difference compared to other groups. There was no statistically significant difference considering smear layer at any levels among the groups with no smear layer formation in group IV. ProTaper rotary instrumentation showed the maximum cleaning efficacy followed by K3 rotary instrumentation in the coronal, middle and apical thirds of the root canal. ProTaper rotary instruments are more efficient than hand and K3 rotary instruments during root canal treatment.

  13. In vitro assessment of cutting efficiency and durability of zirconia removal diamond rotary instruments.

    Science.gov (United States)

    Kim, Joon-Soo; Bae, Ji-Hyeon; Yun, Mi-Jung; Huh, Jung-Bo

    2017-06-01

    Recently, zirconia removal diamond rotary instruments have become commercially available for efficient cutting of zirconia. However, research of cutting efficiency and the cutting characteristics of zirconia removal diamond rotary instruments is limited. The purpose of this in vitro study was to assess and compare the cutting efficiency, durability, and diamond rotary instrument wear pattern of zirconia diamond removal rotary instruments with those of conventional diamond rotary instruments. In addition, the surface characteristics of the cut zirconia were assessed. Block specimens of 3 mol% yttrium cation-doped tetragonal zirconia polycrystal were machined 10 times for 1 minute each using a high-speed handpiece with 6 types of diamond rotary instrument from 2 manufacturers at a constant force of 2 N (n=5). An electronic scale was used to measure the lost weight after each cut in order to evaluate the cutting efficiency. Field emission scanning electron microscopy was used to evaluate diamond rotary instrument wear patterns and machined zirconia block surface characteristics. Data were statistically analyzed using the Kruskal-Wallis test, followed by the Mann-Whitney U test (α=.05). Zirconia removal fine grit diamond rotary instruments showed cutting efficiency that was reduced compared with conventional fine grit diamond rotary instruments. Diamond grit fracture was the most dominant diamond rotary instrument wear pattern in all groups. All machined zirconia surfaces were primarily subjected to plastic deformation, which is evidence of ductile cutting. Zirconia blocks machined with zirconia removal fine grit diamond rotary instruments showed the least incidence of surface flaws. Although zirconia removal diamond rotary instruments did not show improved cutting efficiency compared with conventional diamond rotary instruments, the machined zirconia surface showed smoother furrows of plastic deformation and fewer surface flaws. Copyright © 2016 Editorial Council

  14. Volumetric analysis of hand, reciprocating and rotary instrumentation techniques in primary molars using spiral computed tomography: An in vitro comparative study.

    Science.gov (United States)

    Jeevanandan, Ganesh; Thomas, Eapen

    2018-01-01

    This present study was conducted to analyze the volumetric change in the root canal space and instrumentation time between hand files, hand files in reciprocating motion, and three rotary files in primary molars. One hundred primary mandibular molars were randomly allotted to one of the five groups. Instrumentation was done using Group I; nickel-titanium (Ni-Ti) hand file, Group II; Ni-Ti hand files in reciprocating motion, Group III; Race rotary files, Group IV; prodesign pediatric rotary files, and Group V; ProTaper rotary files. The mean volumetric changes were assessed using pre- and post-operative spiral computed tomography scans. Instrumentation time was recorded. Statistical analysis to access intergroup comparison for mean canal volume and instrumentation time was done using Bonferroni-adjusted Mann-Whitney test and Mann-Whitney test, respectively. Intergroup comparison of mean canal volume showed statistically significant difference between Groups II versus IV, Groups III versus V, and Groups IV versus V. Intergroup comparison of mean instrumentation time showed statistically significant difference among all the groups except Groups IV versus V. Among the various instrumentation techniques available, rotary instrumentation is the considered to be the better instrumentation technique for canal preparation in primary teeth.

  15. Comparison between rotary and manual instrumentation in primary teeth.

    Science.gov (United States)

    Crespo, S; Cortes, O; Garcia, C; Perez, L

    2008-01-01

    The aim of this study was to compare the efficiency in both, preparation time and root canal shape, when using the Nickel Titanium (Ni-Ti) rotary and K-Files hand instrumentation on root canal preparation of single rooted primary teeth. Sixty single rooted primary teeth were selected and divided into two equal groups: Group (I) 30 teeth instrumented with manual K-files and group (II) 30 teeth instrumented with Ni-Ti rotary files (ProFile 0.04). Instrumentation times were calculated and root canal impressions were taken with light bodied silicone in order to evaluate the shape. The data was analyzed with SPSS program using the t-test and the Chi-square test to compare their means. The preparation time with group (I) K-files was significantly higher than in group (II) rotary files (ProFile 0.04), with a p= .005. The ProFile system showed a significantly more favorable canal taper when compared to the K-files system (P= .002). The use of rotary files in primary teeth has several advantages when compared with manual K files: the efficiency in both, preparation time and root canal shape. 1. A decreased working time, that helps maintain patient cooperation by diminishing the potential for tiredness. 2. The shape of the root canal is more conical, favoring a higher quality of the root canal filling, and increasing clinical success.

  16. A scanning electron microscopic study of smear layer remaining following use of Greater Taper rotary instruments

    Directory of Open Access Journals (Sweden)

    S Soumya

    2011-01-01

    Full Text Available The aim of this in vitro study was to evaluate the smear layer in the root canal following the use of Ni-Ti hand ProTaper, HERO shaper and Twisted rotary instruments. Fifteen freshly extracted single rooted human mandibular premolar teeth were selected. Crowns of all teeth were cut off at the cemento-enamel junction with a carborundum disc. The roots were then randomly divided into three groups of 5 samples each. The working length of all teeth was established by the insertion of an endodontic instrument into the canal until its tip is visible at the apical foramen and then subtracted by 0.5 mm. A sequential crown down technique was carried out in all the three groups as follows: Group-I- Specimens in this group were instrumented with ProTaper Ni-Ti hand instruments. Group-II- Specimens were instrumented with HERO shapers. Group-III - The specimens in this group were instrumented with Twisted rotary instruments. Irrigation was done with 3% NaOCl and 15% EDTA in all the three groups. Teeth were carefully split with hammer and chisel and stored in small labeled bottles containing normal saline until SEM evaluation. Results showed that when comparing ProTaper files, Twisted rotary instruments and HERO shaper instruments, HERO shaper series of rotary instruments showed maximum amount of smear layer followed by the Twisted rotary instruments. Hand instruments produced least amount of smear layer.

  17. Apically extruded debris with reciprocating single-file and full-sequence rotary instrumentation systems.

    Science.gov (United States)

    Bürklein, Sebastian; Schäfer, Edgar

    2012-06-01

    The purpose of this in vitro study was to assess the amount of apically extruded debris using rotary and reciprocating nickel-titanium instrumentation systems. Eighty human mandibular central incisors were randomly assigned to 4 groups (n = 20 teeth per group). The root canals were instrumented according to the manufacturers' instructions using the 2 reciprocating single-file systems Reciproc (VDW, Munich, Germany) and WaveOne (Dentsply Maillefer, Ballaigues, Switzerland) and the 2 full-sequence rotary Mtwo (VDW, Munich, Germany) and ProTaper (Dentsply Maillefer, Ballaigues, Switzerland) instruments. Bidistilled water was used as irrigant. The apically extruded debris was collected in preweighted glass vials using the Myers and Montgomery method. After drying, the mean weight of debris was assessed with a microbalance and statistically analyzed using analysis of variance and the post hoc Student-Newman-Keuls test. The time required to prepare the canals with the different instruments was also recorded. The reciprocating files produced significantly more debris compared with both rotary systems (P rotary instruments (P > .05), the reciprocating single-file system Reciproc produced significantly more debris compared with all other instruments (P Instrumentation was significantly faster using Reciproc than with all other instrument (P rotary instrumentation was associated with less debris extrusion compared with the use of reciprocating single-file systems. Copyright © 2012 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  18. ProTaper rotary instrument fracture during root canal preparation: a comparison between rotary and hybrid techniques.

    Science.gov (United States)

    Farid, Huma; Khan, Farhan Raza; Rahman, Munawar

    2013-03-01

    This study aimed to compare the frequency of ProTaper rotary instrument fracture with rotary (conventional) and hybrid (rotary and hand files) canal preparation techniques. Secondary objectives were to determine whether there was an association of ProTaper file fracture with the canal curvature and to compare the mean time required for canal preparation in the two techniques. An in vitro experiment was conducted on 216 buccal canals of extracted maxillary and mandibular first molars. After creating an access cavity and a glide path for each canal, a periapical radiograph was taken and the canal curvature was measured with Schneider's technique. The canals were then randomly divided into Group A (rotary technique) and Group B (hybrid technique). The length of ProTaper files were measured before and after each canal preparation. Time taken for each canal preparation was recorded. A total of seven ProTaper files fractured in Group A (P=0.014) in canals with a curvature >25 degrees (PProTaper rotary files, although time consuming, was safer in canals having a curvature greater than 25 degrees.

  19. Corticotomy-facilitated orthodontics using piezosurgery versus rotary instruments: an experimental study.

    Science.gov (United States)

    Farid, Karim A; Mostafa, Yehya A; Kaddah, Mohammed A; El-Sharaby, Fouad Aly

    2014-10-01

    The aim of this study was to evaluate corticotomy-facilitated orthodontics (CFO) using piezosurgery versus conventional rotary instruments. Ten healthy adult male mongrel dogs of comparable age with a complete set of permanent dentition with average weights between 13-17 kilograms were used. CFO using conventional rotary instruments versus piezosurgery was performed on each dog in a split mouth design. For every dog, mandibular 2nd premolar retraction on each side was attempted after extracting 3rd premolars followed by corticotomy-facilitated orthodontics using conventional rotary surgical burs on the left side and an ultrasonic piezosurgery system on the right side of the same animal. Intraoral measurements of the rate of tooth movement were taken with a sliding caliper. Measurements were performed by the same operator at the time of surgery (appliance delivery) and every month for six months. The dogs were sacrificed after six months from initiation of tooth movement to evaluate the amount of tooth movement for both conventional rotary and piezosurgery corticotomy techniques. A statistically significantly higher mean amount of tooth movement for conventional rotary instrument versus the piezosurgery corticotomy technique was observed at all time intervals. Tooth movement was 1.6 times faster when CFO was done using conventional rotary instruments as compared to a piezosurgery device.

  20. Glide path preparation in S-shaped canals with rotary pathfinding nickel-titanium instruments.

    Science.gov (United States)

    Ajuz, Natasha C C; Armada, Luciana; Gonçalves, Lucio S; Debelian, Gilberto; Siqueira, José F

    2013-04-01

    This study compared the incidence of deviation along S-shaped (double-curved) canals after glide path preparation with 2 nickel-titanium (NiTi) rotary pathfinding instruments and hand K-files. S-shaped canals from 60 training blocks were filled with ink, and preinstrumentation images were obtained by using a stereomicroscope. Glide path preparation was performed by an endodontist who used hand stainless steel K-files (up to size 20), rotary NiTi PathFile instruments (up to size 19), or rotary NiTi Scout RaCe instruments (up to size 20). Postinstrumentation images were taken by using exactly the same conditions as for the preinstrumentation images, and both pictures were superimposed. Differences along the S-shaped canal for the mesial and distal aspects were measured to evaluate the occurrence of deviation. Intragroup analysis showed that all instruments promoted some deviation in virtually all levels. Overall, regardless of the group, deviations were observed in the mesial wall at the canal terminus and at levels 4, 5, 6 and 7 mm and in the distal wall at levels 1, 2, and 3 mm. These levels corresponded to the inner walls of each curvature. Both rotary NiTi instruments performed significantly better than hand K-files at all levels (P instruments showed significantly better results than PathFiles at levels 0, 2, 3, 5, and 6 mm (P rotary NiTi instruments are suitable for adequate glide path preparation because they promoted less deviation from the original canal anatomy when compared with hand-operated instruments. Of the 2 rotary pathfinding instruments, Scout RaCe showed an overall significantly better performance. Copyright © 2013 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  1. Incidence of dentinal defects after root canal preparation: reciprocating versus rotary instrumentation.

    Science.gov (United States)

    Bürklein, Sebastian; Tsotsis, Polymnia; Schäfer, Edgar

    2013-04-01

    The purpose of this study was to evaluate the incidence of dentinal defects after root canal preparation with reciprocating instruments (Reciproc and WaveOne) and rotary instruments. One hundred human central mandibular incisors were randomly assigned to 5 groups (n = 20 teeth per group). The root canals were instrumented by using the reciprocating single-file systems Reciproc and WaveOne and the full-sequence rotary Mtwo and ProTaper instruments. One group was left unprepared as control. Roots were sectioned horizontally at 3, 6, and 9 mm from the apex and evaluated under a microscope by using 25-fold magnification. The presence of dentinal defects (complete/incomplete cracks and craze lines) was noted and analyzed by using the chi-square test. No defects were observed in the controls. All canal preparation created dentinal defects. Overall, instrumentation with Reciproc was associated with more complete cracks than the full-sequence files (P = .021). Although both reciprocating files produced more incomplete cracks apically (3 mm) compared with the rotary files (P = .001), no statistically significant differences were obtained concerning the summarized values of all cross sections (P > .05). Under the conditions of this study, root canal preparation with both rotary and reciprocating instruments resulted in dentinal defects. At the apical level of the canals, reciprocating files produced significantly more incomplete dentinal cracks than full-sequence rotary systems (P < .05). Copyright © 2013 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  2. The effect of intermittent passive ultrasonic irrigation and rotary instruments on microbial colonies of infected root canals

    International Nuclear Information System (INIS)

    AlMadi, Ebtissam M; Balto, Hanan A

    2008-01-01

    To study the effectiveness of reduction of E. faecalis in root canals with passive ultrasonic irrigation (PUI) of 2.25% NaOCl for 1.5 min intermittently during hand instrumentation and continuously after rotary instrumentation. Forty-eight extracted single rooted teeth were filled with E. faecalis suspension and divided into 4 groups. They were either hand instrumented alone using the stepback technique, hand instrumented with PUI of the 2.25% NaOCl intermittently for a total of 1.5 min during the instrumentation, rotary instrumented with ProFile 0.04 alone, or rotary instrumented with PUI of the irrigant for 1.5 min. There was significantly more bacterial growth in the hand instrumented group than in the hand instrumented group with PUI, and marginal significant difference in the hand instrumented group with PUI compared to the rotary instrumented group. No differences were found between the rotary instrumented groups. It was concluded that intermittent use of PUI of 2.25% NaOCl for a total of 1.5 min (half of the current recommended time) during hand instrumentation reduced bacterial colonies significantly. There was no difference in bacterial reduction when rotary instrumentation was used with or without PUI. (author)

  3. Comparison of removed dentin thickness with hand and rotary instruments

    Science.gov (United States)

    Shahriari, Shahriar; Abedi, Hasan; Hashemi, Mahdi; Jalalzadeh, Seyed Mohsen

    2009-01-01

    INTRODUCTION: The aim of this study was to evaluate the amount of dentine removed after canal preparation using stainless steel (SS) hand instruments or rotary ProFile instruments. MATERIALS AND METHODS: Thirty-six extracted human teeth with root canal curvatures less than 30º were embedded in clear polyester resin. The roots were cut horizontally at apical 2, 4 and 7 mm. Dentin thickness was measured at each section and the sections were accurately reassembled using a muffle. Root canals were randomly prepared by SS hand instruments or rotary ProFile instruments. Root sections were again separated, and the remaining dentin thickness was measured. Mann-Whitney U and t tests were performed for analytic comparison of the results. RESULTS: The thickness of removed dentin was significantly different between the two used methods (Pinstrumentation group (Protary instrumentation prepares root canals with a greater conservation of tooth structure. PMID:23940489

  4. Comparison of retreatment ability of full-sequence reciprocating instrumentation and 360° rotary instrumentation.

    Science.gov (United States)

    Capar, Ismail Davut; Gok, Tuba; Orhan, Ezgi

    2015-12-01

    The purpose of the present study was to investigate the amount of root canal filling material after root canal filling removal with 360° rotary instrumentation or reciprocating motion with the same file sequence. Root canals of the 36 mandibular premolars were shaped with ProTaper Universal instruments up to size F2 and filled with corresponding single gutta-percha cone and sealer. The teeth were assigned to two retreatment groups (n = 18): group 1 360° rotational motion and group 2 reciprocating motion of ATR Tecnika motors (1310° clockwise and 578° counterclockwise). Retreatment procedure was performed with ProTaper Universal retreatment files with a sequence of D1-3 and ProTaper Universal F3 instruments. Total time required to remove filling material were recorded. Remaining filling material was examined under stereomicroscope at ×8 magnification. The data were analysed statistically using the Mann-Whitney U test, and testing was performed at 95 % confidence level (p  0.05) in terms of remaining filling material. The total time required for retreatment was shorter in 360° rotational motion group compared to reciprocating motion group (p instruments with reciprocating motion of ATR motor and conventional rotary motion have similar efficacy in root canal filling removal.

  5. Comparison of cyclic fatigue resistance of three different rotary nickel-titanium instruments designed for retreatment.

    Science.gov (United States)

    Inan, Ugur; Aydin, Cumhur

    2012-01-01

    A number of rotary nickel-titanium (NiTi) systems have been developed to provide better, faster, and easier cleaning and shaping of the root canal system, and recently, rotary NiTi systems designed for root canal retreatment have been introduced. Because the main problem with the rotary NiTi files is fracture, the aim of this study was to compare the cyclic fatigue resistance of 3 different rotary NiTi systems designed for root canal retreatment. Total of 60 instruments of 3 different rotary NiTi systems designed for root canal retreatment were used in this study. Twenty R-Endo R3, 20 ProTaper D3, and 20 Mtwo R (Retreatment) 25.05 instruments were tested. Cyclic fatigue testing of instruments was performed by using a device that allowed the instruments to rotate freely inside an artificial canal. Each instrument was rotated until fracture occurred, and the number of cycles to fracture for each instrument was calculated. Representative samples were also evaluated under a scanning electron microscope to confirm the fracture was flexural. Data were analyzed by using 1-way analysis of variance test. R-Endo R3 instruments showed better cyclic fatigue resistance than ProTaper D3 and Mtwo R 25.05 instruments, and the difference was statistically significant (P instruments were more resistant to fatigue failure than ProTaper D3 and Mtwo R 25.05. Copyright © 2012 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  6. Fatigue behavior of lubricated Ni-Ti endodontic rotary instruments

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    A. Brotzu

    2014-04-01

    Full Text Available The use of Ni-Ti alloys in the practice of endodontic comes from their important properties such as shape memory and superelasticity phenomena, good corrosion resistance and high compatibility with biological tissues. In the last twenty years a great variety of nickel-titanium rotary instruments, with various sections and taper, have been developed and marketed. Although they have many advantages and despite their increasing popularity, a major concern with the use of Ni-Ti rotary instruments is the possibility of unexpected failure in use due to several reasons: novice operator handling, presence manufacturing defects, fatigue etc. Recently, the use of an aqueous gel during experimental tests showed a longer duration of the instruments. The aim of the present work is to contribute to the study of the fracture behavior of these endodontic rotary instruments particularly assessing whether the use of the aqueous lubricant gel can extend their operative life stating its reasons. A finite element model (FEM has been developed to support the experimental results. The results were rather contradictory, also because the Perspex (Poly-methyl methacrylate, PMMA cannot simulate completely the dentin mechanical behavior; however the results highlight some interesting points which are discussed in the paper.

  7. Effect of Instrumentation Length and Instrumentation Systems: Hand Versus Rotary Files on Apical Crack Formation - An In vitro Study.

    Science.gov (United States)

    Devale, Madhuri R; Mahesh, M C; Bhandary, Shreetha

    2017-01-01

    Stresses generated during root canal instrumentation have been reported to cause apical cracks. The smaller, less pronounced defects like cracks can later propagate into vertical root fracture, when the tooth is subjected to repeated stresses from endodontic or restorative procedures. This study evaluated occurrence of apical cracks with stainless steel hand files, rotary NiTi RaCe and K3 files at two different instrumentation lengths. In the present in vitro study, 60 mandibular premolars were mounted in resin blocks with simulated periodontal ligament. Apical 3 mm of the root surfaces were exposed and stained using India ink. Preoperative images of root apices were obtained at 100x using stereomicroscope. The teeth were divided into six groups of 10 each. First two groups were instrumented with stainless steel files, next two groups with rotary NiTi RaCe files and the last two groups with rotary NiTi K3 files. The instrumentation was carried out till the apical foramen (Working Length-WL) and 1 mm short of the apical foramen (WL-1) with each file system. After root canal instrumentation, postoperative images of root apices were obtained. Preoperative and postoperative images were compared and the occurrence of cracks was recorded. Descriptive statistical analysis and Chi-square tests were used to analyze the results. Apical root cracks were seen in 30%, 35% and 20% of teeth instrumented with K-files, RaCe files and K3 files respectively. There was no statistical significance among three instrumentation systems in the formation of apical cracks (p=0.563). Apical cracks were seen in 40% and 20% of teeth instrumented with K-files; 60% and 10% of teeth with RaCe files and 40% and 0% of teeth with K3 files at WL and WL-1 respectively. For groups instrumented with hand files there was no statistical significance in number of cracks at WL and WL-1 (p=0.628). But for teeth instrumented with RaCe files and K3 files significantly more number of cracks were seen at WL than

  8. Effect of Instrumentation Length and Instrumentation Systems: Hand Versus Rotary Files on Apical Crack Formation – An In vitro Study

    Science.gov (United States)

    Mahesh, MC; Bhandary, Shreetha

    2017-01-01

    Introduction Stresses generated during root canal instrumentation have been reported to cause apical cracks. The smaller, less pronounced defects like cracks can later propagate into vertical root fracture, when the tooth is subjected to repeated stresses from endodontic or restorative procedures. Aim This study evaluated occurrence of apical cracks with stainless steel hand files, rotary NiTi RaCe and K3 files at two different instrumentation lengths. Materials and Methods In the present in vitro study, 60 mandibular premolars were mounted in resin blocks with simulated periodontal ligament. Apical 3 mm of the root surfaces were exposed and stained using India ink. Preoperative images of root apices were obtained at 100x using stereomicroscope. The teeth were divided into six groups of 10 each. First two groups were instrumented with stainless steel files, next two groups with rotary NiTi RaCe files and the last two groups with rotary NiTi K3 files. The instrumentation was carried out till the apical foramen (Working Length-WL) and 1 mm short of the apical foramen (WL-1) with each file system. After root canal instrumentation, postoperative images of root apices were obtained. Preoperative and postoperative images were compared and the occurrence of cracks was recorded. Descriptive statistical analysis and Chi-square tests were used to analyze the results. Results Apical root cracks were seen in 30%, 35% and 20% of teeth instrumented with K-files, RaCe files and K3 files respectively. There was no statistical significance among three instrumentation systems in the formation of apical cracks (p=0.563). Apical cracks were seen in 40% and 20% of teeth instrumented with K-files; 60% and 10% of teeth with RaCe files and 40% and 0% of teeth with K3 files at WL and WL-1 respectively. For groups instrumented with hand files there was no statistical significance in number of cracks at WL and WL-1 (p=0.628). But for teeth instrumented with RaCe files and K3 files

  9. Comparative Analysis of Crack Propagation in Roots with Hand and Rotary Instrumentation of the Root Canal -An Ex-vivo Study.

    Science.gov (United States)

    Kumari, Manju Raj; Krishnaswamy, Manjunath Mysore

    2016-07-01

    Success of any endodontic treatment depends on strict adherence to 'endodontic triad'. Preparation of root canal system is recognized as being one of the most important stages in root canal treatment. At times, we inevitably end up damaging root dentin which becomes a Gateway for infections like perforation, zipping, dentinal cracks and minute intricate fractures or even vertical root fractures, thereby resulting in failure of treatment. Several factors may be responsible for the formation of dentinal cracks like high concentration of sodium hypochlorite, compaction methods and various canal shaping methods. To compare and evaluate the effects of root canal preparation techniques and instrumentation length on the development of apical root cracks. Seventy extracted premolars with straight roots were mounted on resin blocks with simulated periodontal ligaments, exposing 1-2 mm of the apex followed by sectioning of 1mm of root tip for better visualization under stereomicroscope. The teeth were divided into seven groups of 10 teeth each - a control group and six experimental groups. Subgroup A & B were instrumented with: Stainless Steel hand files (SS) up to Root Canal Length (RCL) & (RCL -1 mm) respectively; sub group C & D were instrumented using ProTaper Universal (PTU) up to RCL and (RCL -1mm) respectively; subgroup E & F were instrumented using ProTaper Next (PTN) up to RCL & (RCL -1 mm) respectively. Stereomicroscopic images of the instrumentation sequence were compared for each tooth. The data was analyzed statistically using descriptive analysis by 'Phi' and 'Cramers' test to find out statistical significance between the groups. The level of significance was set at phand file group showed most cracks followed by ProTaper Universal & ProTaper Next though statistically not significant. Samples instrumented up to 1mm short of working length (RCL-1mm) showed lesser number of cracks. All groups showed cracks formation, the stainless steel group being the highest

  10. Shaping ability of nickel-titanium rotary instruments in curved root canals.

    Science.gov (United States)

    Talati, Ali; Moradi, Saeed; Forghani, Maryam; Monajemzadeh, Ali

    2013-01-01

    Disinfection and subsequent obturation of the root canal space require adequate mechanical enlargement of the canals. The purpose of this in vitro study was to compare the shaping ability of Mtwo, RaCe and Medin rotary instruments during the preparation of curved root canals. Sixty mesiobuccal root canals of mandibular molars with severe curvatures between 25-35(°) and radius of 4-9 mm were randomly divided into three groups of 20 canals each. Using pre- and post-instrumentation radiographs, straightening of the canal and the apical transportation were determined with AutoCAD software. The data were analyzed using Chi square, analysis of variance, and post-hoc tests and the significance level was set at P0.05). Under the conditions of this in vitro study, Mtwo instruments seemed superior to the two other rotary instruments.

  11. Analysis the fatigue using pro taper rotary instruments durin instrumentation of extrated mandibular premolars. SEM observation.

    OpenAIRE

    Siragusa, Martha; Racciatti, Gabriela; García, María

    2007-01-01

    Recibido: Marzo 2007 Aceptado: Julio 2007 Siragusa, Martha; Racciatti, Gabriela y García, María. Analysis the fatigue using pro taper rotary instruments durin instrumentation of extrated mandibular premolars. SEM observation. Electronic Journal of Endodontics Rosario [Online], Volumen 2 Número 13. [octubre 2007]. http://www.endojournal.com.ar/journal/index.php/ejer/article/view/44. ISSN 1666-6143.

  12. Comparison of dentinal damage induced by different nickel-titanium rotary instruments during canal preparation: An in vitro study.

    Science.gov (United States)

    Garg, Shiwani; Mahajan, Pardeep; Thaman, Deepa; Monga, Prashant

    2015-01-01

    To compare dentinal damage caused by hand and rotary nickel-titanium instruments using ProTaper, K3 Endo, and Easy RaCe systems after root canal preparation. One hundred and fifty freshly extracted mandibular premolars were randomly divided into five experimental groups of 30 teeth each and biomechanical preparation was done: Group 1 with unprepared teeth; Group 2 were prepared with hand files; Group 3 with ProTaper rotary instruments; Group 4 with K3 rotary; Group 5 with Easy RaCe rotary instruments. Then, roots were cut horizontally at 3, 6, and 9 mm from apex and were viewed under stereomicroscope. The presence of dentinal defects was noted. Groups were analyzed with the Chi-square test. Significant difference was seen between groups. No defects were found in unprepared roots and those prepared with hand files. ProTaper, K3 rotary, and Easy RaCe preparations resulted in dentinal defects in 23.3%, 10%, and 16.7% of teeth, respectively. More defects were shown in coronal and middle sections, and no defect was seen in apical third. The present study revealed that use of rotary instruments could result in an increased chance for dentinal defects as compared to hand instrumentation.

  13. Mechanical and Metallurgical Properties of Various Nickel-Titanium Rotary Instruments

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    Kyu-Sang Shim

    2017-01-01

    Full Text Available The aim of this study was to investigate the effect of thermomechanical treatment on mechanical and metallurgical properties of nickel-titanium (NiTi rotary instruments. Eight kinds of NiTi rotary instruments with sizes of ISO #25 were selected: ProFile, K3, and One Shape for the conventional alloy; ProTaper NEXT, Reciproc, and WaveOne for the M-wire alloy; HyFlex CM for the controlled memory- (CM- wire; and TF for the R-phase alloy. Torsional fracture and cyclic fatigue fracture tests were performed. Products underwent a differential scanning calorimetry (DSC analysis. The CM-wire and R-phase groups had the lowest elastic modulus, followed by the M-wire group. The maximum torque of the M-wire instrument was comparable to that of a conventional instrument, while those of the CM-wire and R-phase instruments were lower. The angular displacement at failure (ADF for the CM-wire and R-phase instruments was higher than that of conventional instruments, and ADF of the M-wire instruments was lower. The cyclic fatigue resistance of the thermomechanically treated NiTi instruments was higher. DSC plots revealed that NiTi instruments made with the conventional alloy were primarily composed of austenite at room temperature; stable martensite and R-phase were found in thermomechanically treated instruments.

  14. Movement kinematics and cyclic fatigue of NiTi rotary instruments: a systematic review.

    Science.gov (United States)

    Ferreira, F; Adeodato, C; Barbosa, I; Aboud, L; Scelza, P; Zaccaro Scelza, M

    2017-02-01

    The aim of this review was to provide a detailed analysis of the literature concerning the correlation between different movement kinematics and the cyclic fatigue resistance of NiTi rotary endodontic instruments. From June 2014 to August 2015, four independent reviewers comprehensively and systematically searched the Medline (PubMed), EMBASE, Web of Science, Scopus and Google Scholar databases for works published since January 2005, using the following search terms: endodontics; nickel-titanium rotary files; continuous rotation; reciprocating motion; cyclic fatigue. In addition to the electronic searches, manual searches were performed to include articles listed in the reference sections of high-impact published articles that were not indexed in the databases. Laboratory studies in English language were considered for this review. The electronic and manual searches resulted in identification of 75 articles. Based on the inclusion criteria, 32 articles were selected for analysis of full-text copies. Specific analysis was then made of 20 articles that described the effects of reciprocating and continuous movements on cyclic fatigue of the instruments. A wide range of testing conditions and methodologies have been used to compare the cyclic fatigue resistance of rotary endodontic instruments. Most studies report that reciprocating motion improves the fatigue resistance of endodontic instruments, compared to continuous rotation, independent of other variables such as the speed of rotation, the angle or radius of curvature of simulated canals, geometry and taper, or the surface characteristics of the NiTi instruments. © 2016 International Endodontic Journal. Published by John Wiley & Sons Ltd.

  15. Clinical Evaluation of Quality of Obturation and Instrumentation Time using Two Modified Rotary File Systems with Manual Instrumentation in Primary Teeth.

    Science.gov (United States)

    Govindaraju, Lavanya; Jeevanandan, Ganesh; Subramanian, Emg

    2017-09-01

    Pulp therapy in primary teeth has been performed using various instrumentation techniques. However, the conventional instrumentation technique used for root canal preparation in primary teeth is hand instrumentation. Various Nickel-Titanium (Ni-Ti) instruments are available to perform efficient root canal preparation in primary teeth. These Ni-Ti instruments has been designed to aid in better root canal preparation in permanent teeth but are rarely used in primary teeth. It is necessary to assess the feasibility of using these adult rotary files with a modified sequence in primary teeth. To compare the quality of obturation and instrumentation time during root canal preparation using hand files and modified rotary file systems in primary molars. Forty-five primary mandibular molars were randomly assigned to three experimental groups (n=15). Group I was instrumented using k-hand files, Group II with S2 ProTaper universal file and Group III with 0.25 tip 4% taper K3 rotary file. Standardized digital radiographs were taken before and after root canal instrumentation. Root canal preparation time was also recorded. Statistical analysis of the obtained data was done using SPSS Software version 17.0. An intergroup comparison of the instrumentation time and the quality of obturation was done using ANOVA and Chi-square test with the level of significance set at 0.05. No significant differences were noted with regard to the quality of obturation (p=0.791). However, a statistically significant difference was noted in the instrumentation time between the three groups (pProTaper rotary system had significantly lesser instrumentation time when compared to that of K3 rotary system and hand file system. The hand files, S2 ProTaper Universal and K3 0.25 tip 4% taper files systems performed similarly with respect to the quality of obturation. There was a significant difference in instrumentation time with manual instrumentation compared to the modified rotary file systems in primary

  16. Reduction in bacterial counts in infected root canals after rotary or hand nickel-titanium instrumentation--a clinical study.

    Science.gov (United States)

    Rôças, I N; Lima, K C; Siqueira, J F

    2013-07-01

    To compare the antibacterial efficacy of two instrumentation techniques, one using hand nickel-titanium (NiTi) instruments and the other using rotary NiTi instruments, in root canals of teeth with apical periodontitis. Root canals from single-rooted teeth were instrumented using either hand NiTi instruments in the alternated rotation motion technique or rotary BioRaCe instruments. The irrigant used in both groups was 2.5% NaOCl. DNA extracts from samples taken before and after instrumentation were subjected to quantitative analysis by real-time polymerase chain reaction (qPCR). Qualitative analysis was also performed using presence/absence data from culture and qPCR assays. Bacteria were detected in all S1 samples by both methods. In culture analysis, 45% and 35% of the canals were still positive for bacterial presence after hand and rotary NiTi instrumentation, respectively (P > 0.05). Rotary NiTi instrumentation resulted in significantly fewer qPCR-positive cases (60%) than hand NiTi instrumentation (95%) (P = 0.01). Intergroup comparison of quantitative data showed no significant difference between the two techniques. There was no significant difference in bacterial reduction in infected canals after instrumentation using hand or rotary NiTi instruments. In terms of incidence of positive results for bacteria, culture also showed no significant differences between the groups, but the rotary NiTi instrumentation resulted in more negative results in the more sensitive qPCR analysis. © 2013 International Endodontic Journal. Published by John Wiley & Sons Ltd.

  17. An in vitro assessment of the physical properties of novel Hyflex nickel-titanium rotary instruments.

    Science.gov (United States)

    Peters, O A; Gluskin, A K; Weiss, R A; Han, J T

    2012-11-01

    To determine several properties including torsional and fatigue limits, as well as torque during canal preparation, of Hyflex, a rotary instrument manufactured from so-called controlled memory nickel-titanium alloy. The instruments were tested in vitro using a special torque bench that permits both stationary torque tests according to ISO3630-1 and fatigue limit determination, as well as measurement of torque (in Ncm) and apical force (in N) during canal preparation. Fatigue limit (in numbers of cycles to failure) was determined in a 90°, 5 mm radius block-and-rod assembly. Simulated canals in plastic blocks were prepared using both a manufacturer-recommended single-length technique as well as a generic crown-down approach. anova with Bonferroni post hoc procedures was used for statistical analysis. Torque at failure ranged from 0.47 to 1.38 Ncm, with significant differences between instrument sizes (P instruments size 20, .04 taper and size 25, .08 taper, respectively. Torque during canal preparation was significantly higher for small instruments used in the single-length technique but lower for the size 40, .04 taper, compared to a crown-down approach. No instrument fractured; 82% of the instruments used were plastically deformed; however, only 37% of these remained deformed after a sterilization cycle. Hyflex rotary instruments are bendable and flexible and have similar torsional resistance compared to instruments made of conventional NiTi. Fatigue resistance is much higher, and torque during preparation is less, compared to other rotary instruments tested previously under similar conditions. © 2012 International Endodontic Journal.

  18. Fatigue resistance of engine-driven rotary nickel-titanium instruments produced by new manufacturing methods.

    Science.gov (United States)

    Gambarini, Gianluca; Grande, Nicola Maria; Plotino, Gianluca; Somma, Francesco; Garala, Manish; De Luca, Massimo; Testarelli, Luca

    2008-08-01

    The aim of the present study was to investigate whether cyclic fatigue resistance is increased for nickel-titanium instruments manufactured by using new processes. This was evaluated by comparing instruments produced by using the twisted method (TF; SybronEndo, Orange, CA) and those using the M-wire alloy (GTX; Dentsply Tulsa-Dental Specialties, Tulsa, OK) with instruments produced by a traditional NiTi grinding process (K3, SybronEndo). Tests were performed with a specific cyclic fatigue device that evaluated cycles to failure of rotary instruments inside curved artificial canals. Results indicated that size 06-25 TF instruments showed a significant increase (p 0.05) in the mean number of cycles to failure when compared with size 06-20 GT series X instruments. The new manufacturing process produced nickel-titanium rotary files (TF) significantly more resistant to fatigue than instruments produced with the traditional NiTi grinding process. Instruments produced with M-wire (GTX) were not found to be more resistant to fatigue than instruments produced with the traditional NiTi grinding process.

  19. Influence of different manufacturing methods on the cyclic fatigue of rotary nickel-titanium endodontic instruments.

    Science.gov (United States)

    Rodrigues, Renata C V; Lopes, Hélio P; Elias, Carlos N; Amaral, Georgiana; Vieira, Victor T L; De Martin, Alexandre S

    2011-11-01

    The aim of this study was to evaluate, by static and dynamic cyclic fatigue tests, the number of cycles to fracture (NCF) 2 types of rotary NiTi instruments: Twisted File (SybronEndo, Orange, CA), which is manufactured by a proprietary twisting process, and RaCe files (FKG Dentaire, La Chaux-de-Fonds, Switzerland), which are manufactured by grinding. Twenty Twisted Files (TFs) and 20 RaCe files #25/.006 taper instruments were allowed to rotate freely in an artificial curved canal at 310 rpm in a static or a dynamic model until fracture occurred. Measurements of the fractured fragments showed that fracture occurred at the point of maximum flexure in the midpoint of the curved segment. The NCF was significantly lower for RaCe instruments compared with TFs. The NCF was also lower for instruments subjected to the static test compared with the dynamic model in both groups. Scanning electron microscopic analysis revealed ductile morphologic characteristics on the fractured surfaces of all instruments and no plastic deformation in their helical shafts. Rotary NiTi endodontic instruments manufactured by twisting present greater resistance to cyclic fatigue compared with instruments manufactured by grinding. The fracture mode observed in all instruments was of the ductile type. Copyright © 2011 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  20. A comparison of apical transportation between FlexMaster and Twisted Files rotary instruments.

    Science.gov (United States)

    Duran-Sindreu, Fernando; García, Marc; Olivieri, Juan Gonzalo; Mercadé, Montse; Morelló, Sergio; Roig, Miguel

    2012-07-01

    The aim of this study was to evaluate apical transportation in root canals after the use of Twisted Files (TF; SybronEndo, Orange, CA) and FlexMaster (VDW, Munich, Germany) #40/04 rotary files. A double-digital radiographic technique was used to compare apical transportation between the TF and FlexMaster systems. Each rotary system was used to instrument mesial canals from 80 extracted mandibular molars. The central axes of the file imaged before instrumentation (#15 K-file) and the master apical rotary file (#40/04) were superimposed digitally. AutoCAD 2008 (Autodesk Inc, San Rafael, CA) was used to measure apical transportation at 0.5 mm from the working length (WL). The data were analyzed using the Student's t test, and significance was set at P < .05. The mean amount of apical transportation at 0.5 mm from the WL was 0.17 ± 0.09 mm for the FlexMaster group and 0.19 ± 0.12 mm for the TF group. No statistically significant differences in apical transportation were found between the 2 groups. Under the conditions of the study, no statistically significant differences in apical transportation were observed between FlexMaster and TF rotary files. Copyright © 2012 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  1. Post endodontic pain following single-visit root canal preparation with rotary vs reciprocating instruments: a meta-analysis of randomized clinical trials.

    Science.gov (United States)

    Hou, Xiao-Mei; Su, Zheng; Hou, Ben-Xiang

    2017-05-25

    In endodontic therapy, continuous rotary instrumentation reduced debris compared to reciprocal instrumentation, which might affect the incidence of post-endodontic pain (PP). The aim of our study was to assess whether PP incidence and levels were influenced by the choice of rotary or reciprocal instruments. In this meta-analysis the Pubmed and EM databases were searched for prospective clinical randomized trials published before April 20, 2016, using combinations of the keywords: root canal preparation/instrumentation/treatment/therapy; post-operative/endodontic pain; reciprocal and rotary instruments. Three studies were included, involving a total of 1,317 patients, 659 treated with reciprocating instruments and 658 treated with rotary instruments. PP was reported in 139 patients in the reciprocating group and 172 in the rotary group. The PP incidence odds ratio was 1.27 with 95% confidence interval (CI) (0.25, 6.52) favoring rotary instruments. The mild, moderate and severe PP levels odds ratios were 0.31 (0.11, 0.84), 2.24 (0.66, 7.59) and 11.71 (0.63, 218.15), respectively. No evidence of publication bias was found. Rotary instrument choice in endodontic therapy is associated with a lower incidence of PP than reciprocating instruments, while reciprocating instruments are associated with less mild PP incidence.

  2. A Comparative Study of Shaping Ability of four Rotary Systems.

    Science.gov (United States)

    Rubio, Jorge; Zarzosa, José Ignacio; Pallarés, Antonio

    2015-12-01

    This study compared the cutting area, instrumentation time, root canal anatomy preservation and non-instrumented areas obtained by F360(®), Mtwo(®), RaCe(®) and Hyflex(®) files with ISO size 35. 120 teeth with a single straight root and root canal were divided into 4 groups. Working length was calculated by using X-rays. The teeth were sectioned with a handpiece and a diamond disc, and the sections were observed with Nikon SMZ-2T stereoscopic microscope and an Intralux 4000-1 light source. The groups were adjusted with a preoperative analysis with AutoCAD. The teeth were reconstructed by a #10 K-File and epoxy glue. Each group was instrumented with one of the four file systems. The instrumentation time was calculated with a 1/100 second chronometer. The area of the thirds and root canal anatomy preservation were analyzed with AutoCAD 2013 and the non-instrumented areas with AutoCAD 2013 and SMZ-2T stereoscopic microscope. The statistical analysis was made with Levene's Test, ANOVA, Bonferroni Test and Pearson´s Chi-square. Equal variances were shown by Levene's Test (P > 0.05). ANOVA (P > 0.05) showed the absence of significant differences. There were significant differences in the instrumentation time (P 0.05). The 4 different rotary systems produced similar cutting area, root canal anatomy preservation and non-instrumented areas. Regarding instrumentation time, F360(®) was the fastest system statistically.

  3. A Comparative Study of Shaping Ability of four Rotary Systems

    Directory of Open Access Journals (Sweden)

    Jorge Rubio

    2015-01-01

    Full Text Available Purpose: This study compared the cutting area, instrumentation time, root canal anatomy preservation and non-instrumented areas obtained by F360®, Mtwo®, RaCe® and Hyflex® files with ISO size 35. Material and Methods: 120 teeth with a single straight root and root canal were divided into 4 groups. Working length was calculated by using X-rays. The teeth were sectioned with a handpiece and a diamond disc, and the sections were observed with Nikon SMZ-2T stereoscopic microscope and an Intralux 4000-1 light source. The groups were adjusted with a preoperative analysis with AutoCAD. The teeth were reconstructed by a #10 K-File and epoxy glue. Each group was instrumented with one of the four file systems. The instrumentation time was calculated with a 1/100 second chronometer. The area of the thirds and root canal anatomy preservation were analyzed with AutoCAD 2013 and the non-instrumented areas with AutoCAD 2013 and SMZ-2T stereoscopic microscope. The statistical analysis was made with Levene’s Test, ANOVA, Bonferroni Test and Pearson´s Chi-square. Results: Equal variances were shown by Levene’s Test (P > 0.05. ANOVA (P > 0.05 showed the absence of significant differences. There were significant ifferences in the instrumentation time (P 0.05. Conclusions: The 4 different rotary systems produced similar cutting area, root canal anatomy preservation and non-instrumented areas. Regarding instrumentation time, F360® was the fastest system statistically.

  4. Laboratory comparison of the mechanical properties of TRUShape with several nickel-titanium rotary instruments.

    Science.gov (United States)

    Elnaghy, A M; Elsaka, S E

    2017-08-01

    To assess and compare the mechanical properties of TRUShape (TRS) with several nickel-titanium rotary instruments. Cyclic fatigue, torsional resistance, flexibility and surface microhardness of TRS (size 25, 0.06v taper), ProTaper Next X2 (PTN X2, size 25, 0.06 taper), ProTaper Gold (PTG F2; size 25, 0.08 taper) and ProTaper Universal (PTU F2; size 25, 0.08 taper) instruments were evaluated. The topographical structures of the fracture surfaces of instruments were assessed using a scanning electron microscope. The cyclic fatigue resistance, torsional resistance and microhardness data were analysed using one-way analysis of variance (anova) and Tukey's post hoc tests. The fragment length and bending resistance data were analysed statistically with the Kruskal-Wallis H-test and Mann-Whitney U-tests. The statistical significance level was set at P instruments revealed significantly higher resistance to cyclic fatigue than TRS and PTU instruments (P instruments revealed significantly higher torsional resistance compared with the other instruments (P instrument had significantly higher flexibility than the other tested brands (P instruments had lower resistance to cyclic fatigue and lower flexibility compared with PTG and PTN instruments. TRS, PTG and PTU instruments had lower resistance to torsional stress than PTN instruments. TRS and PTG instruments had comparable surface microhardness. © 2016 International Endodontic Journal. Published by John Wiley & Sons Ltd.

  5. Angular deflection of rotary nickel titanium files: a comparative study

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    Gianluca Gambarini

    2009-12-01

    Full Text Available A new manufacturing method of twisting nickel titanium wire to produce rotary nickel titanium (RNT files has recently been developed. The aim of the present study was to evaluate whether the new manufacturing process increased the angular deflection of RNT files, by comparing instruments produced using the new manufacturing method (Twisted Files versus instruments produced with the traditional grinding process. Testing was performed on a total of 40 instruments of the following commercially available RNT files: Twisted Files (TF, Profile, K3 and M2 (NRT. All instruments tested had the same dimensions (taper 0.06 and tip size 25. Test procedures strictly followed ISO 3630-1. Data were collected and statistically analyzed by means ANOVA test. The results showed that TF demonstrated significantly higher average angular deflection levels (P<0.05, than RNT manufactured by a grinding process. Since angular deflection represent the amount of rotation (and consequently deformation that a RNT file can withstand before torsional failure, such a significant improvement is a favorable property for the clinical use of the tested RNT files.

  6. An in vitro comparison of apically extruded debris using three rotary nickel-titanium instruments

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    Tamer Tasdemir

    2010-09-01

    Conclusion: According to this study, all instrumentation techniques apically extruded debris through the apical foramen. However, the BioRaCe instruments induced less extruded debris than the ProTaper Universal and Mtwo rotary systems.

  7. Root Canal Cleaning Efficacy of Rotary and Hand Files Instrumentation in Primary Molars

    Science.gov (United States)

    Nazari Moghaddam, Kiumars; Mehran, Majid; Farajian Zadeh, Hamideh

    2009-01-01

    INTRODUCTION: Pulpectomy of primary teeth is commonly carried out with hand files and broaches; a tricky and time consuming procedure. The purpose of this in vitro study was to compare the cleaning efficacy and time taken for instrumentation of deciduous molars using hand K-files and Flex Master rotary system. MATERIALS AND METHODS: In this study, 68 canals of 23 extracted primary molars with at least two third intact roots and 7-12 mm length were selected. After preparing an access cavity, K-file size #15 was introduced into the root canal and India ink was injected with an insulin syringe. Sixty samples were randomly divided in to experimental groups in group I (n=30), root canals were prepared with hand K-files; in group II (n=30), rotary Flex Master files were used for instrumentation, and in group III 8 remained samples were considered as negative controls. After clearing and root sectioning, the removal of India ink from cervical, middle, and apical thirds was scored. Data was analyzed using student's T-test and Mann-Whitney U test. RESULTS: There was no significant difference between experimental groups cleaning efficacy at the cervical, middle and apical root canal thirds. Only the coronal third scored higher in the hand instrumented group (PInstrumentation with Flex Master rotary files was significantly less time consuming (Protary technique. PMID:23940486

  8. Metallurgical characterization of a new nickel-titanium wire for rotary endodontic instruments.

    Science.gov (United States)

    Alapati, Satish B; Brantley, William A; Iijima, Masahiro; Clark, William A T; Kovarik, Libor; Buie, Caesar; Liu, Jie; Ben Johnson, William

    2009-11-01

    A novel thermomechanical processing procedure has been developed that yields a superelastic (SE) nickel-titanium (NiTi) wire (M-Wire) that laboratory testing shows has improved mechanical properties compared with conventional SE austenitic NiTi wires used for manufacture of rotary instruments. The objective of this study was to determine the origin of the improved mechanical properties. Specimens from 2 batches of M-Wire prepared under different processing conditions and from 1 batch of standard-processed SE wire for rotary instruments were examined by scanning transmission electron microscopy, temperature-modulated differential scanning calorimetry, micro-x-ray diffraction, and scanning electron microscopy with x-ray energy-dispersive spectrometric analyses. The processing for M-Wire yields a microstructure containing martensite, that the proportions of NiTi phases depend on processing conditions, and that the microstructure exhibits pronounced evidence of alloy strengthening. The presence of Ti(2)Ni precipitates in both microstructures indicates that M-Wire and the conventional SE wire for rotary instruments are titanium-rich.

  9. Effect of three different rotary instrumentation systems on postinstrumentation pain: A randomized clinical trial

    Science.gov (United States)

    Subbiya, Arunajatesan; Cherkas, Pavel S.; Vivekanandhan, Paramasivam; Geethapriya, Nagarajan; Malarvizhi, Dhakshinamoorthy; Mitthra, Suresh

    2017-01-01

    Background: Endodontic instrumentation is liable to cause some postinstrumentation pain (PIP). Rotary endodontic instruments differ in their design, metallurgy, surface treatment, etc. Aim: This randomized clinical trial aimed to assess the incidence of PIP after root canal instrumentation with three different rotary endodontic systems which differ in their design, namely, ProTaper, Mtwo, and K3. Materials and Methods: A total of 150 patients between the ages of 25 and 50 were chosen for the study. Teeth with asymptomatic irreversible pulpitis due to carious exposure were selected. The patients received local anesthesia by inferior alveolar nerve block. After preparing the access cavity, root canal instrumentation was done with one of the three instruments (n = 50) and closed dressing was given. PIP was assessed every 12 h for 5 days, and tenderness to percussion was analyzed at the end of 1, 3, and 7 days. Statistical Analysis: Mann–Whitney U-test to determine significant differences at P Rotary endodontic instrumentation causes some degree of PIP and tenderness to percussion. Among the instruments used, Mtwo causes less PIP and tenderness when compared to ProTaper and K3, and there was no difference between ProTaper and K3. Clinical Relevance: PIP is highly subjective and may vary among different subjects. The apical (3 mm) taper of ProTaper was 0.08 followed by a smaller taper, whereas, the other two files were of a constant 0.06 taper, which means there could have been a greater apical extrusion and therefore more PIP. Despite, the mean of the age was similar, there could have been a difference in the size of the canal and therefore a difference in apical extrusion and PIP. PMID:29430103

  10. Comparative evaluation of fracture and defect in reciproc and rotary files in severe curved root canals

    Directory of Open Access Journals (Sweden)

    Mahdis Bagherian

    2015-03-01

    Full Text Available Introduction: Root canal instrumentation is an important phase in root canal therapy. Since success in endodontic treatment depends on file defect and fracture, the aim of this study was to compare the evaluation of defect and fracture in rotary and reciproc files in severe curved root canals. Materials & Methods: In this experimental study, 60 mesial canals of human closed apex molars with more than 30° canal curvature were randomly divided into two groups. In first group M-two rotary files number# 15, 20, and 25 and in second group R25 reciproc file were used for filing, respectively. A ×8 magnifier was applied to evaluate the defect or fracture presence in each side and if it were observed, a new file would be replaced. Therefore, the number of prepared canals with each file and fractured or defective files and the place of fracture in root canal were recorded. Kaplan Meier curve and log rank test were done by using SPSS v.22. Results: In rotary group, seven and two files were fractured and defected, respectively and four files were fractured and no defect was observed in reciproc group. Although the mean of the number of prepared canals until fracture or defect in rotary and reciproc groups was 3.3 and 7.06, respectively, there were no significant differences between two systems. All file’s fractures occurred in apical regions . Conclusion: The results showed that there was no significant difference in defects or fractures of rotary and reciproc systems. Reciproc instruments can be more effective than rotary ones because the root canal preparation in rotary instruments is longer than in reciproc system.

  11. A comparison of root surface instrumentation using manual, ultrasonic and rotary instruments: an in vitro study using scanning electron microscopy.

    Science.gov (United States)

    Marda, Preeti; Prakash, Shobha; Devaraj, C G; Vastardis, S

    2012-01-01

    The commonly accepted idea concerning root planing is that excessive removal of cementum is not necessary for removal of endotoxins. The ideal instrument should enable the removal of all extraneous substances from the root surfaces, without causing any iatrogenic effects. To compare the remaining calculus, loss of tooth substance, and roughness of root surface after root planing with Gracey curette, ultrasonic instrument (Slimline insert FSI-SLI-10S), and DesmoClean rotary bur. The efficiency of calculus removal, the amount of lost tooth substance, and root surface roughness resulting from the use of hand curette, ultrasonic instrument, and rotary bur on 36 extracted mandibular incisors were examined by SEM. We used three indices to measure the changes: Remaining calculus index (RCI), Loss of tooth substance index (LTSI), and Roughness loss of tooth substance index (RLTSI). Twelve samples were treated with each instrument. The time required for instrumentation was also noted. Kruskal-Wallis ANOVA was used for multiple group comparisons and the Mann-Whitney test for group-wise comparisons. Analysis was carried out with SPSS software (version 13). The RCI and LTSI showed nonsignificant differences between the three groups. RLTSI showed a significant difference between Slimline and hand curette as well as Slimline and Desmo-Clean. Slimline showed the least mean scores for RCI, LTSI, and RLTSI. Thus, even though the difference was not statistically significant, Slimline insert was shown to be better than the other methods as assessed by the indices scores and the instrumentation time.

  12. A comparison of three rotary systems and hand instrumentation technique for the elimination of Enterococcus faecalis from the root canal.

    Science.gov (United States)

    Gorduysus, Melahat; Nagas, Emre; Torun, Ozgur Yildirim; Gorduysus, Omer

    2011-12-01

    The aim of this study was to compare the in vitro reduction of a bacterial population in a root canal by mechanical instrumentation using three rotary systems and hand instrumentation technique. The root canals contaminated with a suspension of Enterococcus faecalis were instrumented using ProTaper, K3, HeroShaper and K-file hand instrumentation technique. Later the root canals were sampled. After serial dilutions, samples were incubated in culture media for 24 h. Bacterial colonies were counted and the results were given as number of colony-forming units per millilitre. The results showed that all the canal instrumentation systems reduced the number of bacterial cells in the root canals. Statistically, ProTaper instruments were more effective in reducing the number of bacteria than the other rotary files or hand instruments. © 2010 The Authors. Australian Endodontic Journal © 2010 Australian Society of Endodontology.

  13. Comparison of Single Visit Post Endodontic Pain Using Mtwo Rotary and Hand K-File Instruments: A Randomized Clinical Trial

    Directory of Open Access Journals (Sweden)

    Mohamad Kashefinejad

    2016-08-01

    Full Text Available Objectives: Pain is an unpleasant outcome of endodontic treatment that can be unbearable to patients. Instrumentation techniques may affect the frequency and intensity of post-endodontic pain. This study aimed to compare single visit post endodontic pain using Mtwo (NiTi rotary and hand K-file instruments.Materials and Methods: In this randomized controlled trial, 60 teeth with symptomatic irreversible pulpitis in 53 patients were selected and randomly assigned into two groups of 30 teeth. In group A, the root canals were prepared with Mtwo (NiTi rotary instruments. In group B, the root canals were prepared with hand K-file instruments. Pain assessment was implemented using visual analog scale (VAS at four, eight, 12 and 24 hours after treatment. The acquired data were analyzed using chi-square, Mann-Whitney U and Student’s t-test (P<0.05.Results: Patients treated with rotary instruments experienced significantly less post-endodontic pain than those treated with hand instruments (P<0.001.Conclusion: The use of Mtwo (NiTi rotary instruments in root canal preparation contributed to lower incidence of postoperative pain than hand K-files.

  14. Cyclic fatigue of nickel-titanium rotary instruments in a double (S-shaped) simulated curvature.

    Science.gov (United States)

    Al-Sudani, Dina; Grande, Nicola M; Plotino, Gianluca; Pompa, Giorgio; Di Carlo, Stefano; Testarelli, Luca; Gambarini, Gianluca

    2012-07-01

    The goal of the present study was to test the fatigue resistance of nickel-titanium rotary files in a double curvature (S-shaped) artificial root canal and to compare those results with single curvature artificial root canals. Two nickel-titanium endodontic instruments consisting of identical instrument sizes (constant .06 taper and 0.25 tip diameter) were tested, ProFile instruments and Vortex instruments. Both instruments were tested for fatigue inside an artificial canal with a double curvature and inside a curved artificial canal with a single curvature. Ten instruments for each group were tested to fracture in continuous rotary motion at 300 rpm. Number of cycles to failure (NCF) was calculated to the nearest whole number, and the length of the fractured fragment was measured in millimeters. Data were statistically analyzed with a level of significance set at 95% confidence level. The NCF value was always statistically lower in the double curved artificial canal when compared with the single curve (P instruments of the same size of different brand only in the single curve; ProFile registered a mean of 633.5 ± 75.1 NCF, whereas Vortex registered a mean of 548 ± 48.9 NCF. Regardless of the differences between the instruments used in the present study, the results suggest that the more complex is the root canal, the more adverse are the effects on the cyclic fatigue resistance of the instruments. Copyright © 2012 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  15. [In vitro comparison of root canal preparation with step-back technique and GT rotary file--a nickel-titanium engine driven rotary instrument system].

    Science.gov (United States)

    Krajczár, Károly; Tóth, Vilmos; Nyárády, Zoltán; Szabó, Gyula

    2005-06-01

    The aim of the authors' study was to compare the remaining root canal wall thickness and the preparation time of root canals, prepared either with step-back technique, or with GT Rotary File, an engine driven nickel-titanium rotary instrument system. Twenty extracted molars were decoronated. Teeth were divided in two groups. In Group 1 root canals were prepared with step-back technique. In Group 2 GT Rotary File System was utilized. Preoperative vestibulo-oral X-ray pictures were taken from all teeth with radiovisiograph (RVG). The final preparations at the mesiobuccal canals (MB) were performed with size #30 and palatinal/distal canals with size #40 instruments. Postoperative RVG pictures were taken ensuring the preoperative positioning. The working time was measured in seconds during each preparation. The authors also assessed the remaining root canal wall thickness at 3, 6 and 9 mm from the radiological apex, comparing the width of the canal walls of the vestibulo-oral projections on pre- and postoperative RVG pictures both mesially and buccally. The ratios of the residual and preoperative root canal wall thickness were calculated and compared. The largest difference was found at the MB canals of the coronal and middle third level of the root, measured on the distal canal wall. The ratio of the remaining dentin wall thickness at the coronal and the middle level in the case of step-back preparation was 0.605 and 0.754, and 0.824 and 0.895 in the cases of GT files respectively. The preparation time needed for GT Rotary File System was altogether 68.7% (MB) and 52.5% (D/P canals) of corresponding step-back preparation times. The use of GT Rotary File with comparison of standard step-back method resulted in a shortened preparation time and excessive damage of the coronal part of the root canal could be avoided.

  16. Cyclic fatigue resistance of newly manufactured rotary nickel titanium instruments used in different rotational directions.

    Science.gov (United States)

    Gambarini, Gianlucca; Gergi, Richard; Grande, Nicola Maria; Osta, Nada; Plotino, Gianluca; Testarelli, Luca

    2013-12-01

    The aim of this study was to investigate whether cyclic fatigue resistance is increased for nickel titanium instruments manufactured with improved heating processes in clockwise or counterclockwise continuous rotation. The instruments compared were produced either using the R-phase heat treatment (K3XF; SybronEndo, Orange, CA, USA) or the M-wire alloy (ProFile Vortex; DENTSPLY Tulsa Dental Specialties, Tulsa, OK, USA). Tests were performed with a specific cyclic fatigue device that evaluated cycles to failure of rotary instruments in curved artificial canals. Results indicated no significant difference in resistance to cyclic fatigue when rotary nickel titanium instruments are used in clockwise or counterclockwise continuous rotation. In both directions of rotation, size 04-25 K3XF showed a significant increase (P < 0.05) in the mean number of cycles to failure when compared with size 04-25 ProFile Vortex. © 2012 The Authors. Australian Endodontic Journal © 2012 Australian Society of Endodontology.

  17. A Comparison of Apical Bacterial Extrusion in Manual, ProTaper Rotary, and One Shape Rotary Instrumentation Techniques.

    Science.gov (United States)

    Mittal, Rakesh; Singla, Meenu G; Garg, Ashima; Dhawan, Anu

    2015-12-01

    Apical extrusion of irrigants and debris is an inherent limitation associated with cleaning and shaping of root canals and has been studied extensively because of its clinical relevance as a cause of flare-ups. Many factors affect the amount of extruded intracanal materials. The purpose of this study was to assess the bacterial extrusion by using manual, multiple-file continuous rotary system (ProTaper) and single-file continuous rotary system (One Shape). Forty-two human mandibular premolars were inoculated with Enterococcus faecalis by using a bacterial extrusion model. The teeth were divided into 3 experimental groups (n = 12) and 1 control group (n = 6). The root canals of experimental groups were instrumented according to the manufacturers' instructions by using manual technique, ProTaper rotary system, or One Shape rotary system. Sterilized saline was used as an irrigant, and bacterial extrusion was quantified as colony-forming units/milliliter. The results obtained were statistically analyzed by using one-way analysis of variance for intergroup comparison and post hoc Tukey test for pair-wise comparison. The level for accepting statistical significance was set at P step-back technique exhibiting significantly more bacterial extrusion than the engine-driven systems. Of the 2 engine-driven systems, ProTaper rotary extruded significantly more bacteria than One Shape rotary system (P engine-driven nickel-titanium systems were associated with less apical extrusion. The instrument design may play a role in amount of extrusion. Copyright © 2015 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  18. Comparison of cyclic fatigue resistance of original and counterfeit rotary instruments.

    Science.gov (United States)

    Ertas, Huseyin; Capar, Ismail Davut; Arslan, Hakan; Akan, Ender

    2014-05-31

    In recent years, with the advances in counterfeiting methods, counterfeit products have reached the dental market. The purpose of this study was to compare the cyclic fatigue resistance of original and counterfeit rotary root canal instruments. The cyclic fatigue of original and counterfeit ProTaper F2 endodontic instruments was tested (n = 20) in 3 mm radius steel canals with a 60° angle of curvature. The number of cycles to fracture (NCF) was calculated, and the data were subjected to the Student's t-test (α = 0.05). The original instruments showed better cyclic fatigue resistance than the counterfeit ones (p instruments was very low. As a result, clinicians should be careful not to purchase counterfeit products.

  19. A Survey on Nickel Titanium Rotary Instruments and their Usage Techniques by Endodontists in India.

    Science.gov (United States)

    Patil, Thimmanagowda N; Saraf, Prahlad A; Penukonda, Raghavendra; Vanaki, Sneha S; Kamatagi, Laxmikant

    2017-05-01

    The preference and usage of nickel titanium rotary instruments varies from individual to individual based on their technique, experience with the rotary systems and the clinical situation. Very limited information is available to explain the adoption of changing concepts with respect to nickel titanium rotary instruments pertaining to the endodontists in India. The aim of this study was to conduct a questionnaire survey to acquire the knowledge concerning different NiTi rotary instruments and their usage techniques by endodontists in India. A Survey questionnaire was designed which consisted of 32 questions regarding designation, demographics, experience with rotary instruments, usage of different file systems, usage techniques, frequency of reuse, occurrence of file fracture, reasons and their management was distributed by hand in the national postgraduate convention and also disseminated via electronic medium to 400 and 600 endodontists respectively. Information was collected from each individual to gain insight into the experiences and beliefs of endodontists concerning the new endodontic technology of rotary NiTi instrumentation based on their clinical experience with the rotary systems. The questions were designed to ascertain the problems, patterns of use and to identify areas of perceived or potential concern regarding the rotary instruments and the data acquired was statistically evaluated using Fisher's-exact test and the Chi-Square test. Overall 63.8% (638) endodontists responded. ProTaper was one of the most commonly used file system followed by M two and ProTaper Next. There was a significant co relation between the years of experience and the file re use frequency, preparation technique, file separation, management of file separation. A large number of Endodontists prefer to reuse the rotary NiTi instruments. As there was an increase in the experience, the incidence of file separation reduced with increasing number of re use frequency and with

  20. Cleaning Effectiveness of a Reciprocating Single-file and a Conventional Rotary Instrumentation System.

    Science.gov (United States)

    de Carvalho, Fredson Marcio Acris; Gonçalves, Leonardo Cantanhede de Oliveira; Marques, André Augusto Franco; Alves, Vanessa; Bueno, Carlos Eduardo da Silveira; De Martin, Alexandre Sigrist

    2016-01-01

    To compare cleaning effectiveness by histological analysis of a reciprocating single-file system with ProTaper rotary instruments during the preparation of curved root canals in extracted teeth. A total of 40 root canals with curvatures ranging between 20 - 40 degrees were divided into two groups of 20 canals. Canals were prepared to the following apical sizes: Reciproc size 25 (n=20); ProTaper: F2 (n=20). The normal distribution of data was tested by the Kolmogorov-Smirnov test and the values obtained for the test (Mann-Whitney U test, P .05) between the two groups. The application of reciprocating motion during instrumentation did not result in increased debris when compared with continuous rotation motion, even in the apical part of curved canals. Both instruments resulted in debris in the canal lumen, irrespective of the movement kinematics applied.

  1. Experimental evaluation on the influence of autoclave sterilization on the cyclic fatigue of new nickel-titanium rotary instruments.

    Science.gov (United States)

    Plotino, Gianluca; Costanzo, Alberto; Grande, Nicola M; Petrovic, Renata; Testarelli, Luca; Gambarini, Gianluca

    2012-02-01

    The purpose of this study was to evaluate the effect of autoclave sterilization on cyclic fatigue resistance of rotary endodontic instruments made of traditional and new nickel-titanium (NiTi) alloys. Four NiTi rotary endodontic instruments of the same size (tip diameter 0.40 mm and constant .04 taper) were selected: K3, Mtwo, Vortex, and K3 XF prototypes. Each group was then divided into 2 subgroups, unsterilized instruments and sterilized instruments. The sterilized instruments were subjected to 10 cycles of autoclave sterilization. Twelve files from each different subgroup were tested for cyclic fatigue resistance. Means and standard deviations of number of cycles to failure (NCF) and fragment length of the fractured tip were calculated for each group, and data were statistically analyzed (P instruments for each type of file, differences were statistically significant (P instruments did not show significant differences (P > .05) in the mean NCF as a result of sterilization cycles (K3, 424 versus 439 NCF; Mtwo, 409 versus 419 NCF; Vortex, 454 versus 480 NCF). Comparing the results among the different groups, K3 XF (either sterilized or not) showed a mean NCF significantly higher than all other files (P endodontic instruments except for the K3 XF prototypes of rotary instruments that demonstrated a significant increase of cyclic fatigue resistance. Copyright © 2012 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  2. Comparative evaluation of apically extruded debris during root canal preparation using ProTaper™, Hyflex™ and Waveone™ rotary systems

    Science.gov (United States)

    Surakanti, Jayaprada Reddy; Venkata, Ravi Chandra Polavarapu; Vemisetty, Hari Kumar; Dandolu, Ram Kiran; Jaya, Nagendra Krishna Muppalla; Thota, Shirisha

    2014-01-01

    Background and Aims: Extrusion of any debris during endodontic treatment may potentially cause post-operative complications such as flare-ups. The purpose of this in vitro study was to assess the amount of apically extruded debris during the root canal preparation using rotary and reciprocating nickel-titanium instrumentation systems. Materials and Methods: In this study, 60 human mandibular first premolars were randomly assigned to 3 groups (n = 20 teeth/group). The root canals were instrumented according to the manufacturers’ instructions using the Reciprocating single-file system WaveOne™ (Dentsply Maillefer, Ballaigues, Switzerland) and full-sequence rotary Hyflex CM™ (Coltene Whaledent, Allstetten, Switzerland) and ProTaper™ (Dentsply Maillefer, Ballaigues, Switzerland) instruments. The canals were then irrigated using bidistilled water. The debris that was extruded apically was collected in preweighed eppendorf tubes and assessed with an electronic balance and compared. Statistical Analysis Used: The debris extrusion was compared and statistically analyzed using analysis of variance and the post hoc Student-Newman-Keuls test. Results: The WaveOne™ and ProTaper™ rotary instruments produced significantly more debris compared with Hyflex CM™ rotary instruments (P < 0.05). Conclusions: Under the conditions of this study, all systems that were used resulted in extrusion of apical debris. Full-sequence rotary instrumentation was associated with less debris extrusion compared with the use of reciprocating single-file systems. PMID:24778507

  3. Comparison of Cleaning Efficacy and Instrumentation Time in Primary Molars: Mtwo Rotary Instruments vs. Hand K-Files.

    Science.gov (United States)

    Ramezanali, Fatemeh; Afkhami, Farzaneh; Soleimani, Ali; Kharrazifard, Mohammad Javad; Rafiee, Farshid

    2015-01-01

    Pulpectomy is the preferred treatment for restorable primary teeth with symptomatic irreversible pulpitis or periradicular lesion. Considering the rather new application of rotary files for pulpectomy of primary teeth, the aim of this study was to compare the cleaning efficacy and instrumentation time of hand K-files and Mtwo rotary system for preparation of human primary molars. This experimental study was conducted on 100 extracted primary maxillary and mandibular intact molars with no resorption. Access cavities were prepared and India ink was injected into the root canal on a vibrator using an insulin syringe. Canals were then divided into 5 groups (n=20): in group I, canals were instrumented using K-files up to #25 for mesial and buccal canals and #30 for palatal and distal canals. In group II, canals were prepared using Mtwo rotary files (15/0.05, 20/0.06 and 25/0.06 for mesial and buccal canals and 15/0.05, 20/0.06, 25/0.06 and finally 30/0.05 for distal and palatal canals). In group III, root canals were only irrigated with saline. Groups IV and V were the positive and negative control groups, respectively. The time required for cleaning and preparation of the canals for each of the specimens in groups I, II and III was recorded. The mean score of cleanliness of Mtwo was not significantly different from K-file group (P>0.05). However the mean instrumentation time in Mtwo group was significantly shorter (Protary files were far more time efficient.

  4. Incidence of apical root cracks and apical dentinal detachments after canal preparation with hand and rotary files at different instrumentation lengths.

    Science.gov (United States)

    Liu, Rui; Kaiwar, Anjali; Shemesh, Hagay; Wesselink, Paul R; Hou, Benxiang; Wu, Min-Kai

    2013-01-01

    The aim of this study was to compare the incidence of apical root cracks and dentinal detachments after canal preparation with hand and rotary files at different instrumentation lengths. Two hundred forty mandibular incisors were mounted in resin blocks with simulated periodontal ligaments, and the apex was exposed. The root canals were instrumented with rotary and hand files, namely K3, ProTaper, and nickel-titanium Flex K files to the major apical foramen (AF), short AF, or beyond AF. Digital images of the apical surface of every tooth were taken during the apical enlargement at each file change. Development of dentinal defects was determined by comparing these images with the baseline image. Multinomial logistic regression test was performed to identify influencing factors. Apical crack developed in 1 of 80 teeth (1.3%) with hand files and 31 of 160 teeth (19.4%) with rotary files. Apical dentinal detachment developed in 2 of 80 teeth (2.5%) with hand files and 35 of 160 teeth (21.9%) with rotary files. Instrumentation with rotary files terminated 2 mm short of AF and did not cause any cracks. Significantly less cracks and detachments occurred when instrumentation with rotary files was terminated short of AF, as compared with that terminated at or beyond AF (P hand instruments; instrumentation short of AF reduced the risk of dentinal defects. Copyright © 2013 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  5. Undergraduates’ opinion after 5-year experience with rotary endodontic instruments

    OpenAIRE

    Flávia Sens Fagundes Tomazinho; Gisele Aihara Haragushiku; Flares Baratto Filho; Denise Piotto Leonardi; Maria da Graça Kfouri Lopes; Alexandre Moro

    2011-01-01

    Introduction: Dentistry evolution in the past few years has revolutionized daily practice in some specialties. One of these revolutions has occurred in Endodontics due to the advancement of rotary techniques for root canal preparation and its subsequent incorporation into the teaching of Dentistry undergraduates. Objective: The aim of this study was to report a 5-year experience on the undergraduate laboratorial and clinical use of rotary endodontic preparation at a private university. Materi...

  6. Apical extrusion of bacteria when using reciprocating single-file and rotary multifile instrumentation systems.

    Science.gov (United States)

    Tinoco, J M; De-Deus, G; Tinoco, E M B; Saavedra, F; Fidel, R A S; Sassone, L M

    2014-06-01

    To evaluate ex vivo, apical bacterial extrusion associated with two reciprocating single-file systems (WaveOne and Reciproc) compared with a conventional multifile rotary system (BioRace). Forty-five human single-rooted mandibular incisors were used. Endodontic access cavities were prepared, and root canals were contaminated with an Enterococcus faecalis suspension. Following incubation at 37 °C for thirty days, the contaminated teeth were divided into three groups of 15 specimens each (G1 - Reciproc, G2 - WaveOne and G3 - BioRace). Positive and negative controls consisted of 5 infected teeth and 3 uninfected incisors that were instrumented with one of the tested NiTi systems, respectively. Bacteria extruded from the apical foramen during instrumentation were collected into vials containing 0.9% NaCl. The microbiological samples were taken from the vials and incubated in brain heart agar medium for 24 h. The resulting bacterial titre, in colony-forming units (CFU) per mL, was determined, and these data were analysed by Wilcoxon matched-pairs signed rank test and Kruskal-Wallis H-test. The level of significance was set at α = 0.05. No significant difference was found in the number of CFU between the two reciprocating systems (P = 0.41). The conventional multifile rotary system group was associated with significantly higher CFU than both of the two reciprocating groups (P = 0.01). All instrumentation systems extruded bacteria beyond the foramen. However, both reciprocating single-file systems extruded fewer bacteria apically than the conventional multifile rotary system. © 2013 International Endodontic Journal. Published by John Wiley & Sons Ltd.

  7. Clinical and Radiographic Evaluation of Procedural Errors during Preparation of Curved Root Canals with Hand and Rotary Instruments: A Randomized Clinical Study

    Science.gov (United States)

    Khanna, Rajesh; Handa, Aashish; Virk, Rupam Kaur; Ghai, Deepika; Handa, Rajni Sharma; Goel, Asim

    2017-01-01

    Background: The process of cleaning and shaping the canal is not an easy goal to obtain, as canal curvature played a significant role during the instrumentation of the curved canals. Aim: The present in vivo study was conducted to evaluate procedural errors during the preparation of curved root canals using hand Nitiflex and rotary K3XF instruments. Materials and Methods: Procedural errors such as ledge formation, instrument separation, and perforation (apical, furcal, strip) were determined in sixty patients, divided into two groups. In Group I, thirty teeth in thirty patients were prepared using hand Nitiflex system, and in Group II, thirty teeth in thirty patients were prepared using K3XF rotary system. The evaluation was done clinically as well as radiographically. The results recorded from both groups were compiled and put to statistical analysis. Statistical Analysis: Chi-square test was used to compare the procedural errors (instrument separation, ledge formation, and perforation). Results: In the present study, both hand Nitiflex and rotary K3XF showed ledge formation and instrument separation. Although ledge formation and instrument separation by rotary K3XF file system was less as compared to hand Nitiflex. No perforation was seen in both the instrument groups. Conclusion: Canal curvature played a significant role during the instrumentation of the curved canals. Procedural errors such as ledge formation and instrument separation by rotary K3XF file system were less as compared to hand Nitiflex. PMID:29042727

  8. Comparison of the cleaning capacity of Mtwo and Pro Taper rotary systems and manual instruments in primary teeth

    Science.gov (United States)

    Azar, Mohammad Reza; Safi, Laya; Nikaein, Afshin

    2012-01-01

    Background: Root canal cleaning is an important step in endodontic therapy. In order to develop better techniques, a new generation of endodontic instruments has been designed. The aim of this study was to compare the effectiveness of manual K-files (Mani Co, Tokyo, Japan) and two rotary systems–Mtwo (Dentsply-Maillefer, Ballaigues, Switzerland) and ProTaper (VDW, Munich, Germany)–for root canal preparation in primary molars. Materials and Methods: India ink was injected to 160 mesiobuccal and distal root canals of mandibular primary molars. The teeth were randomly divided into three experimental groups and one control group. In each experimental group, either manual instruments (K-files) or rotary instruments (Mtwo or ProTaper) were used to prepare root canals. After cleaning the canals and clearing the teeth, ink removal was evaluated with a stereomicroscope. Statistical analysis was done with Kruskal–Wallis and Friedman tests. Results: There were no significant differences in cleaning efficiency between manual and rotary instruments. Only ProTaper files performed significantly better in the coronal and middle thirds than in the apical third of the root canal. Conclusion: Manual K-files and the Mtwo and ProTaper rotary systems showed equally acceptable cleaning ability in primary molar root canals. PMID:22623929

  9. Comparison of the cleaning capacity of Mtwo and ProTaper rotary systems and manual instruments in primary teeth

    Directory of Open Access Journals (Sweden)

    Mohammad Reza Azar

    2012-01-01

    Full Text Available Background: Root canal cleaning is an important step in endodontic therapy. In order to develop better techniques, a new generation of endodontic instruments has been designed. The aim of this study was to compare the effectiveness of manual K-files (Mani Co, Tokyo, Japan and two rotary systems-Mtwo (Dentsply-Maillefer, Ballaigues, Switzerland and ProTaper (VDW, Munich, Germany-for root canal preparation in primary molars. Materials and Methods: India ink was injected to 160 mesiobuccal and distal root canals of mandibular primary molars. The teeth were randomly divided into three experimental groups and one control group. In each experimental group, either manual instruments (K-files or rotary instruments (Mtwo or ProTaper were used to prepare root canals. After cleaning the canals and clearing the teeth, ink removal was evaluated with a stereomicroscope. Statistical analysis was done with Kruskal-Wallis and Friedman tests. Results: There were no significant differences in cleaning efficiency between manual and rotary instruments. Only ProTaper files performed significantly better in the coronal and middle thirds than in the apical third of the root canal. Conclusion: Manual K-files and the Mtwo and ProTaper rotary systems showed equally acceptable cleaning ability in primary molar root canals.

  10. Influence of Heat Treatment of Nickel-Titanium Rotary Endodontic Instruments on Apical Preparation: A Micro-Computed Tomographic Study.

    Science.gov (United States)

    de Almeida, Bernardo Corrêa; Ormiga, Fabíola; de Araújo, Marcos César Pimenta; Lopes, Ricardo Tadeu; Lima, Inayá Corrêa Barbosa; dos Santos, Bernardo Camargo; Gusman, Heloisa

    2015-12-01

    The aim of this study was to make a 3-dimensional comparison of the canal transportation and changes in apical geometry using micro-computed tomographic imaging after canal preparation with K3 (SybronEndo, Orange, CA) and K3XF (SybronEndo) file systems. Twenty-eight mandibular molars were randomly divided into 2 groups according to the rotary system used in instrumentation: K3 or K3XF. The specimens were scanned by micro-computed tomographic imaging before and after instrumentation. Images before and after instrumentation from each group were compared with regard to canal volume, surface area, and structure model index (SMI) (paired t test, P instrumentation, the canals from each group were compared regarding the changes in volume, surface area, SMI, and canal transportation in the last 4 apical mm (t test, P Instrumentation with the 2 rotary systems significantly changed the canal volume, surface area, and SMI (P instrument types concerning these parameters (P > .05). There were no significant differences between the 2 groups with regard to canal transportation in the last 4 apical mm (P > .05). Both rotary systems showed adequate canal preparations with reduced values of canal transportation. Heat treatment did not influence changes in root canal geometry in the apical region. Copyright © 2015 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  11. Scanning electron microscopic evaluation of the influence of manual and mechanical glide path on the surface of nickel-titanium rotary instruments in moderately curved root canals: An in-vivo study

    Science.gov (United States)

    Patel, Dishant; Bashetty, Kusum; Srirekha, A.; Archana, S.; Savitha, B.; Vijay, R.

    2016-01-01

    Aim: The aim of this study was to evaluate the influence of manual versus mechanical glide path (GP) on the surface changes of two different nickel-titanium rotary instruments used during root canal therapy in a moderately curved root canal. Materials and Methods: Sixty systemically healthy controls were selected for the study. Controls were divided randomly into four groups: Group 1: Manual GP followed by RaCe rotary instruments, Group 2: Manual GP followed by HyFlex rotary instruments, Group 3: Mechanical GP followed by RaCe rotary instruments, Group 4: Mechanical GP followed by HyFlex rotary instruments. After access opening, GP was prepared and rotary instruments were used according to manufacturer's instructions. All instruments were evaluated for defects under standard error mean before their use and after a single use. The scorings for the files were given at apical and middle third. Statistical Analysis Used: Chi-squared test was used. Results: The results showed that there is no statistical difference between any of the groups. Irrespective of the GP and rotary files used, more defects were present in the apical third when compared to middle third of the rotary instrument. Conclusion: Within the limitations of this study, it can be concluded that there was no effect of manual or mechanical GP on surface defects of subsequent rotary file system used. PMID:27994317

  12. Comparison among manual instruments and PathFile and Mtwo rotary instruments to create a glide path in the root canal preparation of curved canals.

    Science.gov (United States)

    Alves, Vanessa de Oliveira; Bueno, Carlos Eduardo da Silveira; Cunha, Rodrigo Sanches; Pinheiro, Sérgio Luiz; Fontana, Carlos Eduardo; de Martin, Alexandre Sigrist

    2012-01-01

    Nickel-titanium rotary instruments reduce procedural errors and the time required to finish root canal preparation. The goal of this study was to evaluate the occurrences of apical transportation and canal aberrations produced with different instruments used to create a glide path in the preparation of curved root canals, namely manual K-files (Dentsply Maillefer, Ballaigues, Switzerland) and PathFile (Dentsply Maillefer) and Mtwo (Sweden and Martina, Padua, Italy) nickel-titanium rotary files. The mesial canals of 45 mandibular first and second molars (with curvature angles between 25° and 35°) were selected for this study. The specimens were divided randomly into 3 groups with 15 canals each, and canal preparation was performed by an endodontist using #10-15-20 K-type stainless steel manual files (group M), #13-16-19 PathFile rotary instruments (group PF), and #10-15-20 Mtwo rotary instruments (group MT). The double digital radiograph technique was used, pre- and postinstrumentation, to assess whether apical transportation and/or aberration in root canal morphology occurred. The initial and final images of the central axis of the canals were compared by superimposition through computerized analysis and with the aid of magnification. The specimens were analyzed by 3 evaluators, whose calibration was checked using the Kendall agreement test. No apical transportation or aberration in root canal morphology occurred in any of the teeth; therefore, no statistical analysis was conducted. Neither the manual instruments nor the PathFile or Mtwo rotary instruments used to create a glide path had any influence on the occurrence of apical transportation or produced any canal aberration. Copyright © 2012 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  13. Comparison of quality of obturation and instrumentation time using hand files and two rotary file systems in primary molars: A single-blinded randomized controlled trial.

    Science.gov (United States)

    Govindaraju, Lavanya; Jeevanandan, Ganesh; Subramanian, E M G

    2017-01-01

    In permanent dentition, different rotary systems are used for canal cleaning and shaping. Rotary instrumentation in pediatric dentistry is an emerging concept. A very few studies have compared the efficiency of rotary instrumentation for canal preparation in primary teeth. Hence, this study was performed to compare the obturation quality and instrumentation time of two rotary files systems - Protaper, Mtwo with hand files in primary molars. Forty-five primary mandibular molars were randomly allotted to one of the three groups. Instrumentation was done using K-files in Group 1; Protaper in Group 2; and Mtwo in Group 3. Instrumentation time was recorded. The canal filling quality was assessed as underfill, optimal fill, and overfill. Statistical analysis was done using Chi-square, ANOVA, and post hoc Tukey test. No significant difference was observed in the quality of obturation among three groups. Intergroup comparison of the instrumentation time showed a statistically significant difference between the three groups. The use of rotary instrumentation in primary teeth results in marked reduction in the instrumentation time and improves the quality of obturation.

  14. Postoperative Pain after Endodontic Treatment of Asymptomatic Teeth Using Rotary Instruments: A Randomized Clinical Trial

    Science.gov (United States)

    Shahi, Shahriar; Asghari, Vahideh; Rahimi, Saeed; Lotfi, Mehrdad; Samiei, Mohammad; Yavari, Hamidreza; Shakouie, Sahar; Nezafati, Saeed

    2016-01-01

    Introduction: The aim of the present study was to compare the effect of two different rotary instruments on postoperative pain in teeth with asymptomatic irreversible pulpitis. Methods and Materials: A total of 78 mandibular first and second molars were divided into two groups (n=39) and their root canal preparation was carried out with either RaCe or ProTaper rotary instruments. All the subjects underwent one-visit root canal treatment and the severity of postoperative pain was evaluated using visual analog scale (VAS) at 4-, 12-, 24-, 48- and 72-h and 1-week intervals. In addition, the need for taking analgesics was recorded. Data were analyzed with the repeated-measures ANOVA and the Mann-Whitney U test was used for two-by-two comparison. Statistical significance was set at 0.05. Results: Comparison of mean pain severity between the two groups at various postoperative intervals did not reveal any significant differences (P=0.10). The difference in amount of analgesics taken by each groups was not statistically significant (P=0.25). Conclusion: There were no significant differences in the postoperative pain reported between the two groups; which indicates the clinical acceptability of both systems. PMID:26843876

  15. Effects of electropolishing surface treatment on the cyclic fatigue resistance of BioRace nickel-titanium rotary instruments.

    Science.gov (United States)

    Lopes, Hélio P; Elias, Carlos N; Vieira, Victor T L; Moreira, Edson J L; Marques, Raquel V L; de Oliveira, Julio C Machado; Debelian, Gilberto; Siqueira, José F

    2010-10-01

    This study evaluated the influence of electropolishing surface treatment on the number of cycles to fracture of BioRace rotary nickel-titanium endodontic instruments. BioRace size BR5C instruments with or without electropolishing surface treatment were used in an artificial curved canal under rotational speed of 300 rpm until fracture. Fractured surfaces and the helical shafts of fractured instruments were analyzed by scanning electron microscopy (SEM). Polished instruments displayed a significantly higher number of cycles to fracture when compared with nonpolished instruments (P ductile morphologic characteristics. Evaluation of the separated fragments after cyclic fatigue testing showed the presence of microcracks near the fracture surface. Polished instruments exhibited fine cracks that assumed an irregular path (zigzag crack pattern), whereas nonpolished instruments showed cracks running along the machining grooves. Electropolishing surface treatment of BioRace endodontic instruments significantly increased the cyclic fatigue resistance. Copyright © 2010 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  16. Impact of heat treatments on the fatigue resistance of different rotary nickel-titanium instruments.

    Science.gov (United States)

    Braga, Lígia Carolina Moreira; Faria Silva, Ana Cristina; Buono, Vicente Tadeu Lopes; de Azevedo Bahia, Maria Guiomar

    2014-09-01

    The aim of this study was to assess the influence of M-Wire (Dentsply Tulsa Dental Specialties, Tulsa, OK) and controlled memory technologies on the fatigue resistance of rotary nickel-titanium (NiTi) files by comparing files made using these 2 technologies with conventional NiTi files. Files with a similar cross-sectional design and diameter were chosen for the study: new 30/.06 files of the EndoWave (EW; J. Morita Corp, Osaka, Japan), HyFlex (HF; Coltene/Whaledent, Inc, Cuyahoga Falls, OH), ProFile Vortex (PV; Dentsply Tulsa Dental Specialties, Tulsa, OK), and Typhoon (TYP; Clinician's Choice Dental Products, New Milford, CT) systems together with ProTaper Universal F2 instruments (PTU F2; Dentsply Maillefer, Ballaigues, Switzerland). The compositions and transformation temperatures of the instruments were analyzed using x-ray energy-dispersive spectroscopy and differential scanning calorimetry, whereas the mean file diameter values at 3 mm from the tip (D3) were measured using image analysis software. The average number of cycles to failure was determined using a fatigue test device. X-ray energy-dispersive spectroscopy analysis showed that, on average, all the instruments exhibited the same chemical composition, namely, 51% Ni-49% Ti. The PV, TYP, and HF files exhibited increased transformation temperatures. The PTU F2, PV, and TYP files had similar D3 values, which were less than those of the EW and HF files. The average number of cycles to failure values were 150% higher for the TYP files compared with the PV files and 390% higher for the HF files compared with the EW files. M-Wire and controlled memory technologies increase the fatigue resistance of rotary NiTi files. Copyright © 2014 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  17. Comparison of the cleaning capacity of Mtwo and ProTaper rotary systems and manual instruments in primary teeth

    OpenAIRE

    Mohammad Reza Azar; Laya Safi; Afshin Nikaein

    2012-01-01

    Background: Root canal cleaning is an important step in endodontic therapy. In order to develop better techniques, a new generation of endodontic instruments has been designed. The aim of this study was to compare the effectiveness of manual K-files (Mani Co, Tokyo, Japan) and two rotary systems-Mtwo (Dentsply-Maillefer, Ballaigues, Switzerland) and ProTaper (VDW, Munich, Germany)-for root canal preparation in primary molars. Materials and Methods: India ink was injected to 160 mesiobucca...

  18. Mechanical and Metallurgical Properties of Various Nickel-Titanium Rotary Instruments

    OpenAIRE

    Shim, Kyu-Sang; Oh, Soram; Kum, KeeYeon; Kim, Yu-Chan; Jee, Kwang-Koo; Chang, Seok Woo

    2017-01-01

    The aim of this study was to investigate the effect of thermomechanical treatment on mechanical and metallurgical properties of nickel-titanium (NiTi) rotary instruments. Eight kinds of NiTi rotary instruments with sizes of ISO #25 were selected: ProFile, K3, and One Shape for the conventional alloy; ProTaper NEXT, Reciproc, and WaveOne for the M-wire alloy; HyFlex CM for the controlled memory- (CM-) wire; and TF for the R-phase alloy. Torsional fracture and cyclic fatigue fracture tests were...

  19. Effect of autoclaving on the surfaces of TiN -coated and conventional nickel-titanium rotary instruments.

    Science.gov (United States)

    Spagnuolo, G; Ametrano, G; D'Antò, V; Rengo, C; Simeone, M; Riccitiello, F; Amato, M

    2012-12-01

    To evaluate the effects of repeated autoclave sterilization cycles on surface topography of conventional nickel-titanium ( NiTi ) and titanium nitride ( TiN )-coated rotary instruments. A total of 60 NiTi rotary instruments, 30 ProTaper (Dentsply Maillefer) and 30 TiN -coated AlphaKite (Komet/Gebr. Brasseler), were analysed. Instruments were evaluated in the as-received condition and after 1, 5 and 10 sterilization cycles. After sterilization, the samples were observed using scanning electron microscope (SEM), and surface chemical analysis was performed on each instrument with energy dispersive X-ray spectroscopy (EDS). Moreover, the samples were analysed by atomic force microscopy (AFM), and roughness average (Ra) and the root mean square value (RMS) of the scanned surface profiles were recorded. Data were analysed by means of anova followed by Tukey's test. Scanning electron microscope observations revealed the presence of pitting and deep milling marks in all instruments. EDS analysis confirmed that both types of instruments were composed mainly of nickel and titanium, whilst AlphaKite had additional nitride. After multiple autoclave sterilization cycles, SEM examinations revealed an increase in surface alterations, and EDS values indicated changes in chemical surface composition in all instruments. Ra and RMS values of ProTaper significantly increased after 5 (P = 0.006) and 10 cycles (P = 0.002) with respect to the as-received instruments, whilst AlphaKite showed significant differences compared with the controls after 10 cycles (P = 0.03). Multiple autoclave sterilization cycles modified the surface topography and chemical composition of conventional and TiN -coated NiTi rotary instruments. © 2012 International Endodontic Journal.

  20. Comparison of Single Visit Post Endodontic Pain Using Mtwo Rotary and Hand K-File Instruments: A Randomized Clinical Trial.

    Science.gov (United States)

    Kashefinejad, Mohamad; Harandi, Azade; Eram, Saeed; Bijani, Ali

    2016-01-01

    Pain is an unpleasant outcome of endodontic treatment that can be unbearable to patients. Instrumentation techniques may affect the frequency and intensity of post-endodontic pain. This study aimed to compare single visit post endodontic pain using Mtwo (NiTi) rotary and hand K-file instruments. In this randomized controlled trial, 60 teeth with symptomatic irreversible pulpitis in 53 patients were selected and randomly assigned into two groups of 30 teeth. In group A, the root canals were prepared with Mtwo (NiTi) rotary instruments. In group B, the root canals were prepared with hand K-file instruments. Pain assessment was implemented using visual analog scale (VAS) at four, eight, 12 and 24 hours after treatment. The acquired data were analyzed using chi-square, Mann-Whitney U and Student's t-test (Protary instruments experienced significantly less post-endodontic pain than those treated with hand instruments (Protary instruments in root canal preparation contributed to lower incidence of postoperative pain than hand K-files.

  1. [Torque resistance of three different types of nickel-titanium rotary instruments].

    Science.gov (United States)

    Sun, Wei; Hou, Ben-xiang

    2010-10-01

    To compare torsional fracture of three different types of nickel-titanium rotary instruments ProTaper, Hero642 and Mtwo by making a stimulate models in vitro. Through the establishment of model in vitro, compared the different time with 3 kinds of nickel titanium file in cutting-edge bound occurs, and to observe the section of fractured instruments by scanning electron microscope. The resistence to torque was different from three types of nickel titanium instruments. The time to fracture of Mtwo was significantly longer than ProTaper's and Hero642's, but ProTaper's and Hero642's had no significant difference. Three kinds cross-sectional design were different, a lot of toughness nests were seen in broken surface. Most of them were ductile fracture. Time to fracture was influenced by the quality disfigurement. The resistance to torque of Mtwo was better than ProTaper and Hero642. The lifespan was influenced by the design of cross-section. The quality disfigurement of the files reduced the resistance to flexual fatigue.

  2. Effect of canal preparation with TRUShape and Vortex rotary instruments on three-dimensional geometry of oval root canals.

    Science.gov (United States)

    Arias, Ana; Paqué, Frank; Shyn, Stephanie; Murphy, Sarah; Peters, Ove A

    2018-04-01

    The purpose of this study was to assess the geometry of non-round root canals after preparation with TRUShape (a novel instrument with s-shaped longitudinal design) in comparison to conventional rotary instrumentation using micro-computed tomography. Twenty distal root canals of mandibular molars were randomly distributed in two groups to be shaped with either TRUShape or Vortex rotaries. Percentages of unprepared surface and volume of dentin removal for the entire canal and for the apical 4 mm were calculated. Canal transportation and the structure model index (SMI) were assessed. Data were compared with Student t-tests. Shaping with both techniques resulted in similar prepared surface and volume of dentin removed, as well as the extent of canal transportation. The SMI shape factor was significantly lower for TRUShape preparations (P = 0.04) suggesting less rounding during rotary preparation. Although both instruments were suitable for the preparation of oval canals, TRUShape appeared to better conform to the original ribbon-shaped anatomy. © 2017 Australian Society of Endodontology Inc.

  3. Deformation and fracture of Mtwo rotary nickel-titanium instruments after clinical use.

    Science.gov (United States)

    Inan, Ugur; Gonulol, Nihan

    2009-10-01

    In recent years, a number of rotary nickel titanium (NiTi) systems have been developed to provide better, faster, and easier cleaning and shaping of the root canal system. Although the NiTi instruments are more flexible than the stainless steel files, the main problem with the rotary NiTi instruments is the failure of the instruments. The aim of this study was to evaluate the deformation and fracture rate of Mtwo rotary nickel-titanium instruments (VDW, Munich, Germany) discarded after routine clinical use. A total of 593 Mtwo rotary NiTi instruments were collected after clinical use from the clinic of endodontics over 12 months. The length of the files was measured using a digital caliper to determine any fracture, and then all the files were evaluated under a stereomicroscope for defects such as unwinding, curving, or bending and fracture. The fracture faces of separated files were also evaluated under a scanning electron microscope. The data were analyzed using a chi-square and z test. A percentage of all files (25.80%) showed defects, and the major defect was fracture (16.02%). The most frequently fractured file was #10.04 (30.39%). Deformations without fracture were mostly observed on #15.05 files (25.47%). A higher rate of deformation was observed for #10.04 and #15.05 files. Therefore, these files should be considered as single-use instruments. Because cyclic fatigue was the cause of 71.58% of the instrument fractures, it is also important not to exceed the maximum number of usage recommended by the manufacturer and discard the instruments on a regular basis.

  4. Analysis of kinematic, kinetic and electromyographic patterns during root canal preparation with rotary and manual instruments

    Directory of Open Access Journals (Sweden)

    Braulio Pasternak-Júnior

    2012-02-01

    Full Text Available OBJECTIVE: This study assessed the muscular activity during root canal preparation through kinematics, kinetics, and electromyography (EMG. MATERIAL AND METHODS: The operators prepared one canal with RaCe rotary instruments and another with Flexo-files. The kinematics of the major joints was reconstructed using an optoelectronic system and electromyographic responses of the flexor carpi radialis, extensor carpi radialis, brachioradialis, biceps brachii, triceps brachii, middle deltoid, and upper trapezius were recorded. The joint torques of the shoulder, elbow and wrist were calculated using inverse dynamics. In the kinematic analysis, angular movements of the wrist and elbow were classified as low risk factors for work-related musculoskeletal disorders. With respect to the shoulder, the classification was medium-risk. RESULTS: There was no significant difference revealed by the kinetic reports. The EMG results showed that for the middle deltoid and upper trapezius the rotary instrumentation elicited higher values. The flexor carpi radialis and extensor carpi radialis, as well as the brachioradialis showed a higher value with the manual method. CONCLUSION: The muscular recruitment for accomplishment of articular movements for root canal preparation with either the rotary or manual techniques is distinct. Nevertheless, the rotary instrument presented less difficulty in the generation of the joint torque in each articulation, thus, presenting a greater uniformity of joint torques.

  5. Analysis of kinematic, kinetic and electromyographic patterns during root canal preparation with rotary and manual instruments

    Science.gov (United States)

    PASTERNAK-JÚNIOR, Braulio; de SOUSA NETO, Manoel Damião; DIONÍSIO, Valdeci Carlos; PÉCORA, Jesus Djalma; SILVA, Ricardo Gariba

    2012-01-01

    Objective This study assessed the muscular activity during root canal preparation through kinematics, kinetics, and electromyography (EMG). Material and Methods The operators prepared one canal with RaCe rotary instruments and another with Flexo-files. The kinematics of the major joints was reconstructed using an optoelectronic system and electromyographic responses of the flexor carpi radialis, extensor carpi radialis, brachioradialis, biceps brachii, triceps brachii, middle deltoid, and upper trapezius were recorded. The joint torques of the shoulder, elbow and wrist were calculated using inverse dynamics. In the kinematic analysis, angular movements of the wrist and elbow were classified as low risk factors for work-related musculoskeletal disorders. With respect to the shoulder, the classification was medium-risk. Results There was no significant difference revealed by the kinetic reports. The EMG results showed that for the middle deltoid and upper trapezius the rotary instrumentation elicited higher values. The flexor carpi radialis and extensor carpi radialis, as well as the brachioradialis showed a higher value with the manual method. Conclusion The muscular recruitment for accomplishment of articular movements for root canal preparation with either the rotary or manual techniques is distinct. Nevertheless, the rotary instrument presented less difficulty in the generation of the joint torque in each articulation, thus, presenting a greater uniformity of joint torques. PMID:22437679

  6. A comparative evaluation of the increase in root canal surface area and canal transportation in curved root canals by three rotary systems: A cone-beam computed tomographic study

    Science.gov (United States)

    Prasanthi, Nalam NVD; Rambabu, Tanikonda; Sajjan, Girija S; Varma, K Madhu; Satish, R Kalyan; Padmaja, M

    2016-01-01

    Aim: The aim of this study was to measure the increase in root canal surface area and canal transportation after biomechanical preparation at 1, 3, and 5 mm short of the apex with three different rotary systems in both continuous rotary and reciprocating rotary motions. Materials and Methods: Sixty freshly extracted human mandibular molars with mesial root canal curvatures between 20° and 30° were included in the study. Teeth were randomly distributed into three groups (n = 20). Biomechanical preparations were done in all the mesial canals. In Group 1, instrumentation was done with ProTaper universal rotary files, Group 2, with K3XF rotary files, and Group 3, with LSX rotary files. Each group was further subdivided into subgroups A and B (n = 10) where instrumentation was done by continuous rotary and reciprocating rotary techniques, respectively. Increase in root canal surface area and canal transportation was measured using the preoperative and postoperative cone-beam computed tomography scans. Statistical Analysis: The data were analyzed by one-way ANOVA followed by Tukey pairwise multiple comparison tests. Results: Increase in root canal surface area was significantly more (P 0.05) in increase of root canal surface area and canal transportation between continuous rotary and reciprocating rotary techniques for ProTaper Universal, K3XF and LSX groups. Conclusion: LSX rotary system showed minimal increase of root canal surface area and minimal canal transportation when compared to ProTaper and K3XF rotary systems. PMID:27656062

  7. Apical extrusion of debris and irrigant using hand and rotary systems: A comparative study

    Science.gov (United States)

    Ghivari, Sheetal B; Kubasad, Girish C; Chandak, Manoj G; Akarte, NR

    2011-01-01

    Aim: To evaluate and compare the amount of debris and irrigant extruded quantitatively by using two hand and rotary nickel–titanium (Ni–Ti) instrumentation techniques. Materials and Methods: Eighty freshly extracted mandibular premolars having similar canal length and curvature were selected and mounted in a debris collection apparatus. After each instrument change, 1 ml of distilled water was used as an irrigant and the amount of irrigant extruded was measured using the Meyers and Montgomery method. After drying, the debris was weighed using an electronic microbalance to determine its weight. Statistical analysis used: The data was analyzed statistically to determine the mean difference between the groups. The mean weight of the dry debris and irrigant within the group and between the groups was calculated by the one-way ANOVA and multiple comparison (Dunnet D) test. Results: The step-back technique extruded a greater quantity of debris and irrigant in comparison to other hand and rotary Ni–Ti systems. Conclusions: All instrumentation techniques extrude debris and irrigant, it is prudent on the part of the clinician to select the instrumentation technique that extrudes the least amount of debris and irrigant, to prevent a flare-up phenomena. PMID:21814364

  8. Evaluation of conventional, protaper hand and protaper rotary instrumentation system for apical extrusion of debris, irrigants and bacteria- An in vitro randomized trial

    OpenAIRE

    Kalra, Pinky; Rao, Arathi; Suman, Ethel; Shenoy, Ramya; Suprabha, Baranya-Shrikrishna

    2017-01-01

    Background Endodontic instrumentation carries the risk of over extrusion of debris and bacteria. The technique used and the type of instrumentation influences this risk. Aim The purpose of this study was to evaluate and compare the K-file, ProTaper hand and ProTaper rotary instrumentation systems for the amount of apically extruded debris, irrigant solution and intracanal bacteria. Design Experimental single blinded randomized type of in vitro study with sample of 30 single rooted teeth. Endo...

  9. In Vitro Comparison of Apically Extruded Debris during Root Canal Preparation of Mandibular Premolars with Manual and Rotary Instruments

    Science.gov (United States)

    Soi, Sonal; Yadav, Suman; Sharma, Sumeet; Sharma, Mohit

    2015-01-01

    Background and aims. During root canal preparation, debris extruded beyond the apical foramen may result in periapical inflammation and postoperative pain. To date no root canal preparation method has been developed that extrudes no periapical debris. The purpose of this study was to identify a system leading to minimal extrusion of debris from the apical foramen. The study was conducted to comparatively evaluate the amount of apical extrusion of debris during root canal preparation using hand ProTaper and GT rotary and RaCe rotary instruments using crown-down technique. Materials and methods. Ninety freshly extracted human single-rooted mandibular premolars were equally assigned to three groups (n=30). The root canals were instrumented using hand ProTaper, GT rotary and RaCe rotary systems. Debris and irrigant extruded from the apical foramen were collected into vials. The mean weight of the remaining debris was calculated for each group and subjected to statistical analysis. Results. ANOVA was used to compare the mean dry weights of the debris extruded in the three groups, followedby post hoc Tukey tests for multiple comparisons the between groups. Highly significant differences were found in the amount of debris extruded among all the groups (P<0.001). The ProTaper group exhibited the highest mean debris weight (0.8293±0.05433 mg) and the RaCe system exhibited the lowest mean debris weight (0.1280±0.01606 mg). Conclusion. All the systems tested resulted in apical extrusion of debris. However, the hand ProTaper files extruded a significantly higher amount of debris than GT and RaCe systems. PMID:26697144

  10. In Vitro Comparison of Apically Extruded Debris during Root Canal Preparation of Mandibular Premolars with Manual and Rotary Instruments.

    Science.gov (United States)

    Soi, Sonal; Yadav, Suman; Sharma, Sumeet; Sharma, Mohit

    2015-01-01

    Background and aims. During root canal preparation, debris extruded beyond the apical foramen may result in periapical inflammation and postoperative pain. To date no root canal preparation method has been developed that extrudes no periapical debris. The purpose of this study was to identify a system leading to minimal extrusion of debris from the apical foramen. The study was conducted to comparatively evaluate the amount of apical extrusion of debris during root canal preparation using hand ProTaper and GT rotary and RaCe rotary instruments using crown-down technique. Materials and methods. Ninety freshly extracted human single-rooted mandibular premolars were equally assigned to three groups (n=30). The root canals were instrumented using hand ProTaper, GT rotary and RaCe rotary systems. Debris and irrigant extruded from the apical foramen were collected into vials. The mean weight of the remaining debris was calculated for each group and subjected to statistical analysis. Results. ANOVA was used to compare the mean dry weights of the debris extruded in the three groups, followedby post hoc Tukey tests for multiple comparisons the between groups. Highly significant differences were found in the amount of debris extruded among all the groups (PProTaper group exhibited the highest mean debris weight (0.8293±0.05433 mg) and the RaCe system exhibited the lowest mean debris weight (0.1280±0.01606 mg). Conclusion. All the systems tested resulted in apical extrusion of debris. However, the hand ProTaper files extruded a significantly higher amount of debris than GT and RaCe systems.

  11. In Vitro Comparison of Apically Extruded Debris during Root Canal Preparation of Mandibular Premolars with Manual and Rotary Instruments

    Directory of Open Access Journals (Sweden)

    Sonal Soi

    2015-09-01

    Full Text Available Background and aims. During root canal preparation, debris extruded beyond the apical foramen may result in periapical inflammation and postoperative pain. To date no root canal preparation method has been developed that extrudes no peri-apical debris. The purpose of this study was to identify a system leading to minimal extrusion of debris from the apical fo-ramen. The study was conducted to comparatively evaluate the amount of apical extrusion of debris during root canal prepa-ration using hand ProTaper and GT rotary and RaCe rotary instruments using crown-down technique. Materials and methods. Ninety freshly extracted human single-rooted mandibular premolars were equally assigned to three groups (n=30. The root canals were instrumented using hand ProTaper, GT rotary and RaCe rotary systems. Debris and irrigant extruded from the apical foramen were collected into vials. The mean weight of the remaining debris was calcu-lated for each group and subjected to statistical analysis. Results. ANOVA was used to compare the mean dry weights of the debris extruded in the three groups, followedby post hoc Tukey tests for multiple comparisons the between groups. Highly significant differences were found in the amount of debris extruded among all the groups (P<0.001. The ProTaper group exhibited the highest mean debris weight (0.8293±0.05433 mg and the RaCe system exhibited the lowest mean debris weight (0.1280±0.01606 mg. Conclusion. All the systems tested resulted in apical extrusion of debris. However, the hand ProTaper files extruded a sig-nificantly higher amount of debris than GT and RaCe systems.

  12. WaveOne Rotary Instruments after Clinical Use.

    Science.gov (United States)

    Shen, Ya; Coil, Jeffrey M; Mo, Anthony John; Wang, Zhejun; Hieawy, Ahmed; Yang, Yan; Haapasalo, Markus

    2016-02-01

    The purpose of this study was to evaluate the incidence and mode of WaveOne (Dentsply Tulsa Dental Specialties, Tulsa, OK) instrument defects after single use at different endodontic clinics. A total of 438 WaveOne instruments were collected after clinical use from the 4 specialist clinics over a 12-month period and from 1 graduate program over a 20-month period. The incidence and type of instrument defects were analyzed. The lateral surfaces of part of the defective instruments and fracture surfaces of fractured files were examined using scanning electron microscopy. Unused and clinically used files were examined by a nanoindentation test. Of the 438 WaveOne instruments collected, 42 (9.6%) had defects: 40 (9.1%) were distorted and 2 (0.5%) files had fractured, 1 Small and 1 Primary file. Clear differences in the frequency of defects were found among the 3 file sizes; the occurrence of distortion and fracture were highest with the Small file (21.2% and 0.7%, respectively) followed by the Primary file (4.4% and 0.4%, respectively) (P Instruments from various clinics showed no significantly different occurrence of instrument deformation. Unwinding occurred at 1.2-3.1 mm from the tip. No significant difference in nanohardness was detected among unused and used instruments. The risk of WaveOne fracture is very low when files are singly used by endodontists and residents. Unwinding of the files occurred most frequently in the Small file. The frequency of defects of WaveOne instruments were not influenced by the operator. Copyright © 2016 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  13. Smear layer and debris removal using manual Ni-Ti files compared with rotary Protaper Ni- Ti files - An In-Vitro SEM study.

    Science.gov (United States)

    Reddy, J M V Raghavendra; Latha, Prasanna; Gowda, Basavana; Manvikar, Varadendra; Vijayalaxmi, D Benal; Ponangi, Kalyana Chakravarthi

    2014-02-01

    Predictable successful endodontic therapy depends on correct diagnosis, effective cleaning, shaping and disinfection of the root canals and adequate obturation. Irrigation serves as a flush to remove debris, tissue solvent and lubricant from the canal irregularities; however these irregularities can restrict the complete debridement of root canal by mechanical instrumentation.Various types of hand and rotary instruments are used for the preparation of the root canal system to obtain debris free canals. The purpose of this study was to evaluate the amount of smear layer and debris removal on canal walls following the using of manual Nickel-Titanium (NiTi) files compared with rotary ProTaperNiTi files using a Scanning Electron Microscope in two individual groups. A comparative study consisting of 50 subjects randomized into two groups - 25 subjects in Group A (manual) and 25 subjects in Group B (rotary) was undertaken to investigate and compare the effects of smear layer and debris between manual and rotary NiTi instruments. Chi square test was used to find the significance of smear layer and debris removal in the coronal, middle and apical between Group A and Group B. Both systems of Rotary ProTaperNiTi and manual NiTi files used in the present study, did not create completely clean root canals. Manual NiTi files produced significantly less smear layer and debris compared to Rotary ProTaperNiTi instruments. Rotary instruments were less time consuming when compared to manual instruments. Instrument separation was not found to be significant with both the groups. Both systems of Rotary ProTaperNiTi and manual NiTi files used did not produce completely clean root canals. Manual NiTi files produced significantly less smear layer and debris compared to Rotary protaper instruments. How to cite the article: Reddy JM, Latha P, Gowda B, Manvikar V, Vijayalaxmi DB, Ponangi KC. Smear layer and debris removal using manual Ni-Ti files compared with rotary Protaper Ni-Ti files

  14. CT evaluation of canal preparation using rotary and hand NI-TI instruments: An in vitro study

    Science.gov (United States)

    Nagaraja, Shruthi; Sreenivasa Murthy, B V

    2010-01-01

    Background: Controlled, uniformly tapered radicular preparation is a great challenge in endodontics. Improper preparation can lead to procedural errors like transportation of foramen, uneven dentine thickness, stripping of root canal, formation of ledge, zip, and elbow in curved canals. These procedural errors and their sequel can adversely affect the prognosis of treatment. Aim/Objectives: The present in vitro study aims to evaluate canal preparation based on the following factors: canal transportation, remaining dentine thickness and comparing centering ability between hand Ni-Ti K files and ProTaper rotary Ni-Ti instruments using computed tomography (CT). Materials and Methods: For evaluation, 30 mesiobuccal roots of maxillary molars were selected. Of these, 15 roots were distributed into two groups where Group 1 included hand instrumentation with Ni-Ti K-files; and Group 2 comprised ProTaper NiTi rotary system. Pre instrumentation and post instrumentation three-dimensional CT images were obtained from root cross-sections that were 1 mm thick from apex to the canal orifice; scanned images were then superimposed and compared. Result: It was observed that the manual technique using hand Ni-Ti K-file produced lesser canal transportation and maintained greater dentine thickness than the rotary ProTaper technique at middle and coronal third and this difference was statistically significant. No significant difference was seen with regard to canal transportation and remaining root dentine at apical levels. With regard to centering ratio, no significant difference was seen between both the groups at all levels. Conclusion: ProTaper should be used judiciously, especially in curved canals, as it causes higher canal transportation and thinning of root dentine at middle and coronal levels. None of the groups showed optimal centering ability. PMID:20582214

  15. CT evaluation of canal preparation using rotary and hand NI-TI instruments: An in vitro study.

    Science.gov (United States)

    Nagaraja, Shruthi; Sreenivasa Murthy, B V

    2010-01-01

    Controlled, uniformly tapered radicular preparation is a great challenge in endodontics. Improper preparation can lead to procedural errors like transportation of foramen, uneven dentine thickness, stripping of root canal, formation of ledge, zip, and elbow in curved canals. These procedural errors and their sequel can adversely affect the prognosis of treatment. The present in vitro study aims to evaluate canal preparation based on the following factors: canal transportation, remaining dentine thickness and comparing centering ability between hand Ni-Ti K files and ProTaper rotary Ni-Ti instruments using computed tomography (CT). For evaluation, 30 mesiobuccal roots of maxillary molars were selected. Of these, 15 roots were distributed into two groups where Group 1 included hand instrumentation with Ni-Ti K-files; and Group 2 comprised ProTaper NiTi rotary system. Pre instrumentation and post instrumentation three-dimensional CT images were obtained from root cross-sections that were 1 mm thick from apex to the canal orifice; scanned images were then superimposed and compared. It was observed that the manual technique using hand Ni-Ti K-file produced lesser canal transportation and maintained greater dentine thickness than the rotary ProTaper technique at middle and coronal third and this difference was statistically significant. No significant difference was seen with regard to canal transportation and remaining root dentine at apical levels. With regard to centering ratio, no significant difference was seen between both the groups at all levels. ProTaper should be used judiciously, especially in curved canals, as it causes higher canal transportation and thinning of root dentine at middle and coronal levels. None of the groups showed optimal centering ability.

  16. Incidence of apical root cracks and apical dentinal detachments after canal preparation with hand and rotary files at different instrumentation lengths

    NARCIS (Netherlands)

    Liu, R.; Kaiwar, A.; Shemesh, H.; Wesselink, P.R.; Hou, B.; Wu, M.K.

    2013-01-01

    Introduction The aim of this study was to compare the incidence of apical root cracks and dentinal detachments after canal preparation with hand and rotary files at different instrumentation lengths. Methods Two hundred forty mandibular incisors were mounted in resin blocks with simulated

  17. Evaluation of surface characteristics of rotary nickel-titanium instruments produced by different manufacturing methods.

    Science.gov (United States)

    Inan, U; Gurel, M

    2017-02-01

    Instrument fracture is a serious concern in endodontic practice. The aim of this study was to investigate the surface quality of new and used rotary nickel-titanium (NiTi) instruments manufactured by the traditional grinding process and twisting methods. Total 16 instruments of two rotary NiTi systems were used in this study. Eight Twisted Files (TF) (SybronEndo, Orange, CA, USA) and 8 Mtwo (VDW, Munich, Germany) instruments were evaluated. New and used of 4 experimental groups were evaluated using an atomic force microscopy (AFM). New and used instruments were analyzed on 3 points along a 3 mm. section at the tip of the instrument. Quantitative measurements according to the topographical deviations were recorded. The data were statistically analyzed with paired samples t-test and independent samples t-test. Mean root mean square (RMS) values for new and used TF 25.06 files were 10.70 ± 2.80 nm and 21.58 ± 6.42 nm, respectively, and the difference between them was statistically significant (P instruments produced by twisting method (TF 25.06) had better surface quality than the instruments produced by traditional grinding process (Mtwo 25.06 files).

  18. Influence of rotational speed on the cyclic fatigue of rotary nickel-titanium endodontic instruments.

    Science.gov (United States)

    Lopes, Hélio P; Ferreira, Alessandra A P; Elias, Carlos N; Moreira, Edson J L; de Oliveira, Júlio C Machado; Siqueira, José F

    2009-07-01

    During the preparation of curved canals, rotary nickel-titanium (NiTi) instruments are subjected to cyclic fatigue, which can lead to instrument fracture. Although several factors may influence the cyclic fatigue resistance of instruments, the role of the rotational speed remains uncertain. This study was intended to evaluate the effects of rotational speed on the number of cycles to fracture of rotary NiTi instruments. ProTaper Universal instruments F3 and F4 (Maillefer SA, Ballaigues, Switzerland) were used in an artificial curved canal under rotational speeds of 300 rpm or 600 rpm. The artificial canal was made of stainless steel, with an inner diameter of 1.5 mm, total length of 20 mm, and arc at the end with a curvature radius of 6 mm. The arc length was 9.4 mm and 10.6 mm on the straight part. The number of cycles required to fracture was recorded. Fractured surfaces and the helical shafts of the fractured instruments were analyzed by scanning electron microscopy. The results showed approximately a 30% reduction in the observed number of cycles to fracture as rotational speed was increased from 300 to 600 RPM (p ductile type, and no plastic deformation was observed on the helical shaft of fractured instruments. The present findings for both F3 and F4 ProTaper instruments revealed that the increase in rotational speed significantly reduced the number of cycles to fracture.

  19. Evaluation of Dentin Defect Formation during Retreatment with Hand and Rotary Instruments: A Micro-CT Study.

    Science.gov (United States)

    Yilmaz, Ayca; Helvacioglu-Yigit, Dilek; Gur, Cansu; Ersev, Handan; Kiziltas Sendur, Gullu; Avcu, Egemen; Baydemir, Canan; Abbott, Paul Vincent

    2017-01-01

    The purpose of this study was to compare the incidence and longitudinal propagation of dentin defects after gutta-percha removal with hand and rotary instruments using microcomputed tomography. Twenty mandibular incisors were prepared using the balanced-force technique and scanned in a 19.9  μ m resolution. Following filling with the lateral compaction technique, gutta-percha was removed with ProTaper Universal Retreatment (PTUR) or hand instruments. After rescanning, a total of 24,120 cross-sectional images were analyzed. The numbers, types, and longitudinal length changes of defects were recorded. Defects were observed in 36.90% of the cross sections. A total of 73 defects were comprised of 87.67% craze lines, 2.73% partial cracks, and 9.58% fractures. No significant difference in terms of new defect formation was detected between the retreatment groups. The apical and middle portions of the roots had more dentin defects than the coronal portions. Defects in three roots of the PTUR instrument group increased in length. Under the conditions of this in vitro study, gutta-percha removal seemed to not increase the incidence of dentin defect formation, but the longitudinal defect propagation finding suggests possible cumulative dentinal damage due to additional endodontic procedures. Hand and rotary instrumentation techniques caused similar dentin defect formation during root canal retreatment.

  20. Evaluation of Dentin Defect Formation during Retreatment with Hand and Rotary Instruments: A Micro-CT Study

    Directory of Open Access Journals (Sweden)

    Ayca Yilmaz

    2017-01-01

    Full Text Available The purpose of this study was to compare the incidence and longitudinal propagation of dentin defects after gutta-percha removal with hand and rotary instruments using microcomputed tomography. Twenty mandibular incisors were prepared using the balanced-force technique and scanned in a 19.9 μm resolution. Following filling with the lateral compaction technique, gutta-percha was removed with ProTaper Universal Retreatment (PTUR or hand instruments. After rescanning, a total of 24,120 cross-sectional images were analyzed. The numbers, types, and longitudinal length changes of defects were recorded. Defects were observed in 36.90% of the cross sections. A total of 73 defects were comprised of 87.67% craze lines, 2.73% partial cracks, and 9.58% fractures. No significant difference in terms of new defect formation was detected between the retreatment groups. The apical and middle portions of the roots had more dentin defects than the coronal portions. Defects in three roots of the PTUR instrument group increased in length. Under the conditions of this in vitro study, gutta-percha removal seemed to not increase the incidence of dentin defect formation, but the longitudinal defect propagation finding suggests possible cumulative dentinal damage due to additional endodontic procedures. Hand and rotary instrumentation techniques caused similar dentin defect formation during root canal retreatment.

  1. Ex vivo study on root canal instrumentation of two rotary nickel-titanium systems in comparison to stainless steel hand instruments.

    Science.gov (United States)

    Vaudt, J; Bitter, K; Neumann, K; Kielbassa, A M

    2009-01-01

    To investigate instrumentation time, working safety and the shaping ability of two rotary nickel-titanium (NiTi) systems (Alpha System and ProTaper Universal) in comparison to stainless steel hand instruments. A total of 45 mesial root canals of extracted human mandibular molars were selected. On the basis of the degree of curvature the matched teeth were allocated randomly into three groups of 15 teeth each. In group 1 root canals were prepared to size 30 using a standardized manual preparation technique; in group 2 and 3 rotary NiTi instruments were used following the manufacturers' instructions. Instrumentation time and procedural errors were recorded. With the aid of pre- and postoperative radiographs, apical straightening of the canal curvature was determined. Photographs of the coronal, middle and apical cross-sections of the pre- and postoperative canals were taken, and superimposed using a standard software. Based on these composite images the portion of uninstrumented canal walls was evaluated. Active instrumentation time of the Alpha System was significantly reduced compared with ProTaper Universal and hand instrumentation (P < 0.05; anova). No instrument fractures occurred in any of the groups. The Alpha System revealed significantly less apical straightening compared with the other instruments (P < 0.05; Mann-Whitney U test). In the apical cross-sections Alpha System resulted in significantly less uninstrumented canal walls compared with stainless steel files (P < 0.05; chi-squared test). Despite the demonstrated differences between the systems, an apical straightening effect could not be prevented; areas of uninstrumented root canal wall were left in all regions using the various systems.

  2. Evidence for Reduced Fatigue Resistance of Contemporary Rotary Instruments Exposed to Body Temperature.

    Science.gov (United States)

    de Vasconcelos, Rafaela Andrade; Murphy, Sarah; Carvalho, Claudio Antonio Talge; Govindjee, Rajiv G; Govindjee, Sanjay; Peters, Ove A

    2016-05-01

    The purpose of this study was to evaluate the effect of 2 different temperatures (20°C and 37°C) on the cyclic fatigue life of rotary instruments and correlate the results with martensitic transformation temperatures. Contemporary nickel-titanium rotary instruments (n = 20 each and tip size #25, including Hyflex CM [Coltene, Cuyahoga Falls, OH], TRUShape [Dentsply Tulsa Dental Specialties, Tulsa, OK], Vortex Blue [Dentsply Tulsa Dental Specialties], and ProTaper Universal [Dentsply Tulsa Dental Specialties]) were tested for cyclic fatigue at room temperature (20°C ± 1°C) and at body temperature (37°C ± 1°C). Instruments were rotated until fracture occurred in a simulated canal with an angle curvature of about 60° and a radius curvature of 3 mm; the center of the curvature was 4.5 mm from the instrument tip. The number of cycles to fracture was measured. Phase transformation temperatures for 2 instruments of each brand were analyzed by differential scanning calorimetry. Data were analyzed using the t test and 1-way analysis of variance with the significance level set at 0.05. For the tested size and at 20°C, Hyflex CM showed the highest resistance to fracture; no significant difference was found between TRUShape and Vortex Blue, whereas ProTaper Universal showed the lowest resistance to fracture. At 37°C, resistance to fatigue fracture was significantly reduced, up to 85%, for the tested instruments (P rotary instruments tested. Copyright © 2016 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  3. Comparison of the remaining dentin thickness in the root after hand and four rotary instrumentation techniques: an in vitro study.

    Science.gov (United States)

    Rao, M S Rama; Shameem, Abdul; Nair, Rashmi; Ghanta, Sureshbabu; Thankachan, Rekha P; Issac, Johnson K

    2013-07-01

    The aim of the present study was to compare the remaining dental thickness (RDT) in the mesiobuccal root of mandibular first molars at 3 and 7 mm from the anatomic apex after instrumentation with ProTaper, light speed LSX, K3 and M2 and to compare with that of K-files. In this study, 60 extracted, untreated human mandibular first molars with fully formed apices, with curvature less than 35° and no root resorption were used. Prepared specimens were cut horizontally at 3 and 7 mm short of anatomic apex. The least dentin thickness from canal to external root surface was observed under 3× magnification and recorded using Clemax measuring tool and the sections were reassembled. Group I-instrumentation with ProTaper, group II-instrumentation with K3, group III-instrumentation with Light Speed LSX, group IV-instrumentation with M2 and group V- instrumentation with K-files and RDT was measured. Results showed that group V removed lesser amount of dentin compared to all other groups while all the three instrumentation techniques removed almost equal amount of dentin apically. Cleaning and shaping of the root canal space involves the elimination of pathogenic contents as well as attaining a uniform specific shape. However, the RDT following the use of various intraradicular procedures is an important factor to be considered as an iatrogenic cause that may result in root fracture. To avoid this, newer rotary instruments are being introduced.

  4. The ability of different nickel-titanium rotary instruments to induce dentinal damage during canal preparation

    NARCIS (Netherlands)

    Bier, C.A.S.; Shemesh, H.; Tanomaru-Filho, M.; Wesselink, P.R.; Wu, M.K.

    2009-01-01

    The purpose of this study was to compare the incidence of dentinal defects (fractures and craze lines) after canal preparation with different nickel-titanium rotary files. Two hundred sixty mandibular premolars were selected. Forty teeth were left unprepared (n = 40). The other teeth were prepared

  5. A comparison of instrumentation using Naviflex and Profile nickel-titanium engine-driven rotary instruments.

    Science.gov (United States)

    Ottosen, S R; Nicholls, J I; Steiner, J C

    1999-06-01

    This study was designed to compare the changes in canal configuration resulting from instrumentation by either Profile or Naviflex instruments. Forty mesial canals in extracted human molar teeth were embedded and sectioned at two root levels. Reassembled teeth were instrumented with a modified crown-down technique as described in the Profile training video for Profile files and in a similar manner for Naviflex instruments. Superimposed pre- and postinstrumented cross-sectional root images were projected, traced, and scanned into a computer for analysis. Canal movement, in relation to the furca, and canal area change were recorded. The results showed no significant difference in canal center movement or canal area change between the Profile or Naviflex groups. The degree of canal curvature had no effect on canal center movement or canal area change.

  6. Fracture resistance of dental nickel-titanium rotary instruments with novel surface treatment: Thin film metallic glass coating.

    Science.gov (United States)

    Chi, Chih-Wen; Deng, Yu-Lun; Lee, Jyh-Wei; Lin, Chun-Pin

    2017-05-01

    Dental nickel-titanium (NiTi) rotary instruments are widely used in endodontic therapy because they are efficient with a higher success rate. However, an unpredictable fracture of instruments may happen due to the surface characteristics of imperfection (or irregularity). This study assessed whether a novel surface treatment could increase fatigue fracture resistance of dental NiTi rotary instruments. A 200- or 500-nm thick Ti-zirconium-boron (Ti-Zr-B) thin film metallic glass was deposited on ProTaper Universal F2 files using a physical vapor deposition process. The characteristics of coating were analyzed by scanning electron microscopy, transmission electron microscopy, and X-ray diffractometry. In cyclic fatigue tests, the files were performed in a simulated root canal (radius=5 mm, angulation=60°) under a rotating speed of 300rpm. The fatigue fractured cross sections of the files were analyzed with their fractographic performances through scanning electron microscopy images. The amorphous structure of the Ti-Zr-B coating was confirmed by transmission electron microscopy and X-ray diffractometry. The surface of treated files presented smooth morphologies without grinding irregularity. For the 200- and 500-nm surface treatment groups, the coated files exhibited higher resistance of cyclic fatigue than untreated files. In fractographic analysis, treated files showed significantly larger crack-initiation zone; however, no significant differences in the areas of fatigue propagation and catastrophic fracture were found compared to untreated files. The novel surface treatment of Ti-Zr-B thin film metallic glass on dental NiTi rotary files can effectively improve the fatigue fracture resistance by offering a smooth coated surface with amorphous microstructure. Copyright © 2016. Published by Elsevier B.V.

  7. Preparation of severely curved simulated root canals using engine-driven rotary and conventional hand instruments.

    Science.gov (United States)

    Szep, S; Gerhardt, T; Leitzbach, C; Lüder, W; Heidemann, D

    2001-03-01

    This in vitro study evaluated the efficacy and safety of six different nickel-titanium engine-driven instruments used with a torque-controlled engine device and nickel-titanium hand and stainless steel hand instruments in preparation of curved canals. A total of 80 curved (36 degrees) simulated root canals were prepared. Images before and after were superimposed, and instrumentation areas were observed. Time of instrumentation, instrument failure, change in working length and weight loss were also recorded. Results show that stainless steel hand instruments cause significantly less transportation towards the inner wall of the canal than do nickel-titanium hand instruments. No instrument fracture occurred with hand instruments, but 30-60% breakage of instruments was recorded during instrumentation with the engine-driven devices. The working length was maintained by all types of instruments. Newly developed nickel-titanium rotary files were not able to prevent straightening of the severely curved canals when a torque-controlled engine-driven device was used.

  8. The effect of brushing motion on the cyclic fatigue of rotary nickel titanium instruments

    Directory of Open Access Journals (Sweden)

    Gianluca Gambarini

    2010-12-01

    Full Text Available The goal of the study is to evaluate if the use of rotary nickel-titanium (RNT instruments, as Hedstroem files, is safe. Twelve twisted files (TF RNT instruments size 06-25 were selected and randomly divided in 2 groups of 6 instruments each. Group A (new instruments were used as control. Group B (test instruments were clinically used only as Hedstroem files in a canal that had been previously instrumented to the working length with other 06-25 RNT instruments. Group B instruments were used only in the straight portion of the canal (1 minute at 1000 rpm. A cyclic fatigue test was performed for each instrument of groups. Data were statistically analyzed (Student's t-test. Results showed no significant difference (P > 0.05 between groups A and B. Data confirmed that the use of TF instruments as Hedstroem files is a safe procedure. Cross section images and volumes of the same instrument, before and after cyclic fatigue testing, have been obtained by means of microtomographic analysis to evaluate possible microstructure alterations.

  9. The efficacy of ProTaper Universal rotary retreatment instrumentation to remove single gutta-percha cones cemented with several endodontic sealers.

    Science.gov (United States)

    Ersev, H; Yilmaz, B; Dinçol, M E; Dağlaroğlu, R

    2012-08-01

    To evaluate residual root filling material following removal of three newly developed root canal sealers used with a matched-taper single-cone root filling technique and to compare the efficacy of ProTaper Universal rotary retreatment instruments with that of a conventional manual technique. The canals of 120 palatal roots in maxillary molar teeth were instrumented with EndoWave nickel-titanium rotary instruments and filled using Hybrid Root SEAL, EndoSequence BC Sealer, Activ GP system or AH Plus with matched-taper single gutta-percha cones. The root fillings were then removed with ProTaper Universal retreatment rotary instruments or a manual technique. Buccolingual and proximal digital radiographs of the roots were exposed to determine the area of remaining filling material in the coronal, middle and apical thirds. The area percentages of remaining filling material in each third and total canal area were calculated. Data were analysed statistically with Kruskal-Wallis and Mann-Whitney U-tests. The level of significance was set at PProTaper groups. When using gross radiographic criteria, the Activ GP was more effectively removed from root canals than AH Plus with hand instrumentation. Hybrid Root SEAL, EndoSequence BC Sealer and AH Plus were removed to a similar extent. ProTaper Universal retreatment instruments were as safe and effective as hand instruments in reaching the working length. © 2012 International Endodontic Journal.

  10. A Comparative SEM Investigation of Smear Layer Remaining on Dentinal Walls by Three Rotary NiTi Files with Different Cross Sectional Designs in Moderately Curved Canals

    Science.gov (United States)

    Kakkar, Pooja; Vats, Asit

    2015-01-01

    Objective: The objective of this study was to compare the smear layer formed on root canal walls during canal preparation of extracted human teeth by Twisted, Mtwo, and ProTaper rotary nickel titanium instruments. Materials and Methods: Sixty single rooted human premolar teeth with root curvature rotary nickel titanium instruments were used, Twisted (SybronEndo, Orange, CA, USA), Mtwo (VDW, Munich, Germany) and ProTaper (Dentsply Maillefer, Ballaigues, Switzerland) according to manufacturer’s instructions to instrument the root canals. Irrigation for all groups was performed after each instrument change with 3ml of 3% sodium hypochlorite followed by Glyde (File Prep, Dentsply, Maillefer, Ballaigues, Switzerland) as chelator paste and lubricant. Three different areas (coronal, middle and apical thirds) of the root canal were evaluated using scanning electron microscopy (SEM). The canal wall of each sample was assessed and compared using a predefined scale for the presence or absence of smear layer. Data were analysed statistically using ANOVA and Tukey HSD test Results: All three groups showed statistically significant more smear layer in the apical thirds of the canal as compared to the coronal and middle thirds (protary file system produced significantly less smear layer (protary instruments in the apical portion. Twisted Files resulted in less smear layer formation in the apical thirds of the canal compared to ProTaper rotary instruments but were statistically insignificant. Conclusion: Completely clean root canals were not found after instrumentation with any of the three instruments. Under the confines of this study Mtwo instruments produced significantly cleaner dentin wall surfaces throughout the canal length in comparison to Twisted and ProTaper rotary files. Twisted Files proved to be comparable to ProTaper rotary instruments with respect to canal cleanliness in the apical thirds of the root canal. PMID:25954704

  11. SEM analysis of defects and wear on Ni-Ti rotary instruments.

    Science.gov (United States)

    Arantes, Werington Borges; da Silva, Celso Monteiro; Lage-Marques, José Luiz; Habitante, Sandramarcia; da Rosa, Luiz Carlos Laureano; de Medeiros, João Marcelo Ferreira

    2014-01-01

    SEM analysis of endodontic instruments from a Ni-Ti rotary system was assessed, before and after using them, considering their defects and deformations. Twenty Twisted File®, BioRąCe®, Mtwo®, and EndoWave® instruments were micrographed at 190× magnification. The files were washed and micrographed again to view alterations as to the presence or absence of irregular edges, grooves, microcavities, and scraping. Simulated root canal preparations were performed using these instruments. The instruments were cleaned and received a microscopic analysis after being used five times. After analysis tests were tested using Fisher's exact test and Kappa to evaluate the concordance among examiners. There was a statistically significant difference with respect to deformations between Twisted File® and other instruments (p  0.05). All Twisted File® instruments showed the same defects; however damage were lower than those found in BioRace® and Mtwo®. The Endowave® did not show the same defects. In accordance with the data we conclude that the presence of defects was higher in Twisted File® instruments as the instruments and BioRace® Mtwo® brand, the defect rate was smaller and Endowave® instruments had no defects. Regarding the presence of wear after five uses among the groups all instruments showed changes in their cutting blades. © 2014 Wiley Periodicals, Inc.

  12. Evaluation of conventional, protaper hand and protaper rotary instrumentation system for apical extrusion of debris, irrigants and bacteria- An in vitro randomized trial.

    Science.gov (United States)

    Kalra, Pinky; Rao, Arathi; Suman, Ethel; Shenoy, Ramya; Suprabha, Baranya-Shrikrishna

    2017-02-01

    Endodontic instrumentation carries the risk of over extrusion of debris and bacteria. The technique used and the type of instrumentation influences this risk. The purpose of this study was to evaluate and compare the K-file, ProTaper hand and ProTaper rotary instrumentation systems for the amount of apically extruded debris, irrigant solution and intracanal bacteria. Experimental single blinded randomized type of in vitro study with sample of 30 single rooted teeth. Endodontic access cavities were prepared and the root canals were filled with the suspension of E. faecalis . Myers and Montogomery Model was used to collect apically extruded debris and irrigant. Canals were prepared using K files, Hand protapers and Protaper rotary files. Non Parametric test like Kruskal-Wallis and Mann-Whitney U test were applied to determine the significant differences among the group. Tests revealed statistically significant difference between the amount of debris and number of bacteria extruded by the ProTaper hand and the K-files. No statistically significant difference was observed between the amounts of irrigant extruded by the ProTaper hand and the K-file system. Statistically significant differences were observed between the amounts of bacteria and irrigant extruded by the ProTaper rotary and the Protaper hand. No statistically significant difference was observed between the amounts of debris extruded by the ProTaper hand and the K-file system. Amount of apical extrusion of irrigant solution, bacteria and debris are significantly greater with K File instruments and least with Protaper rotary instruments. Key words: Protaper, rotary, periapical extrusion.

  13. Deformation and fracture of K3 rotary nickel-titanium endodontic instruments after clinical use.

    Science.gov (United States)

    Shen, S M; Deng, M; Wang, P P; Chen, X M; Zheng, L W; Li, H L

    2016-11-01

    The aim was to evaluate the incidence and type of defects that occurred with K3 rotary nickel-titanium instruments during routine clinical use. A total of 2397 K3 (G-PACKS, SybronEndo, West Collins, Orange, CA, USA) instruments were collected from a graduate endodontic clinic over 21 months. All the instruments were limited to a maximum use of 30 canal preparations. The collected instruments were measured by a digital caliper to determine whether any fractures had occurred and then were visually inspected for deformation and fracture under a stereomicroscope. The surfaces of fractured instruments were further evaluated under a scanning electron microscope. Data were analysed using chi-square test and Kruskal-Wallis test. The incidence of instrument defect was 5.63%, consisting of 3.59% fractures and 2.05% deformations. The defect rates of 0.04 and 0.06 files were statistically higher than the other taper groups (P  0.05). For the fractured instruments, 63.95% failed from flexural fatigue, whilst 36.05% failed from torsion. Flexural fracture was the major mode of fracture for instruments with larger taper. A routine check for instrument integrity particularly for 0.04 and 0.06 files at high magnification is recommended after each clinical use. © 2015 International Endodontic Journal. Published by John Wiley & Sons Ltd.

  14. A high-precision instrument for mapping of rotational errors in rotary stages

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Weihe; Lauer, Kenneth; Chu, Yong; Nazaretski, Evgeny

    2014-10-02

    A rotational stage is a key component of every X-ray instrument capable of providing tomographic or diffraction measurements. To perform accurate three-dimensional reconstructions, runout errors due to imperfect rotation (e.g.circle of confusion) must be quantified and corrected. A dedicated instrument capable of full characterization and circle of confusion mapping in rotary stages down to the sub-10 nm level has been developed. A high-stability design, with an array of five capacitive sensors, allows simultaneous measurements of wobble, radial and axial displacements. The developed instrument has been used for characterization of two mechanical stages which are part of an X-ray microscope.

  15. Postoperative quality of life following single-visit root canal treatment performed by rotary or reciprocating instrumentation: a randomized clinical trial.

    Science.gov (United States)

    Pasqualini, D; Corbella, S; Alovisi, M; Taschieri, S; Del Fabbro, M; Migliaretti, G; Carpegna, G C; Scotti, N; Berutti, E

    2016-11-01

    To compare the impact of rotary and reciprocating instrumentation on postoperative quality of life (POQoL) after single-visit primary root canal treatment. A randomized controlled clinical trial was designed and carried out in a University endodontic practice in northern Italy. Healthy subjects with asymptomatic irreversible pulpitis, symptomatic irreversible pulpitis or pulp necrosis with or without apical periodontitis (symptomatic or asymptomatic) scheduled for primary root canal treatment were enrolled. Single-visit root canal treatment was performed with ProTaper ™ S1-S2-F1-F2 (rotary group, n = 23) and WaveOne ™ Primary (reciprocating group, n = 24). Irrigation was performed with 5% NaOCl and 10% EDTA. Root canal filling was performed with the continuous-wave technique and ZOE sealer. POQoL indicators were evaluated for 7 days post-treatment. The variation of each indicator over time was compared using anova for repeated measures (P rotary group (mean, P = 0.077; maximum, P = 0.015). Difficulty in eating (P = 0.017), in performing daily activities (P = 0.023), in sleeping (P = 0.021) and in social relations (P = 0.077), was more evident in the reciprocating group. Patients' perception of the impact of treatment on POQoL was more favourable in the rotary group (P = 0.006). Multirooted tooth type and pre-existing periradicular inflammation were associated with a decrease in POQoL. Reciprocating instrumentation affected POQoL to a greater extent than rotary instrumentation. © 2015 International Endodontic Journal. Published by John Wiley & Sons Ltd.

  16. Dynamic and cyclic fatigue of engine-driven rotary nickel-titanium endodontic instruments.

    Science.gov (United States)

    Haïkel, Y; Serfaty, R; Bateman, G; Senger, B; Allemann, C

    1999-06-01

    The absence of adequate testing standards for engine-driven nickel-titanium (NiTi) instruments necessitates further study of these instruments in all areas. This study examined three groups of engine-driven rotary NiTi endodontic instruments (Profile, Hero, and Quantec) and assessed the times for dynamic fracture in relation to the radius of curvature to which the instruments were subjected during preparation, with the instrument diameter determined by size and taper and the mode by which the fracture occurred. Ten instruments were randomly selected representing each size and taper for each group and for each radius of curvature: 600 in total. The instruments were rotated at 350 rpm and introduced into a tempered steel curve that simulated a canal. Two radii of curvature of canals were used: 5 and 10 mm. Time at fracture was noted for all files, and the fracture faces of each file were analyzed with scanning electron microscopy. Radius of curvature was found to be the most significant factor in determining the fatigue resistance of the files. As radius of curvature decreased, fracture time decreased. Taper of files was found to be significant in determining fracture time. As diameter increased, fracture time decreased. In all cases, fracture was found to be of a ductile nature, thus implicating cyclic fatigue as a major cause of failure and necessitating further analyses and setting of standards in this area.

  17. Comparison of fracture and deformation in the rotary endodontic instruments: Protaper versus K-3 system.

    Science.gov (United States)

    Nagi, Sana Ehsen; Khan, Farhan Raza; Rahman, Munawar

    2016-03-01

    This experimental study was done on extracted human teeth to compare the fracture and deformation of the two rotary endodontic files system namely K-3 and Protapers. It was conducted at the dental clinics of the Aga Khan University Hospital, Karachi, A log of file deformation or fracture during root canal preparation was kept. The location of fracture was noted along with the identity of the canal in which fracture took place. The fracture in the two rotary systems was compared. SPSS 20 was used for data analysis. Of the 172(80.4%) teeth possessing more than 15 degrees of curvature, fracture occurred in 7(4.1%) cases and deformation in 10(5.8%). Of the 42(19.6%) teeth possessing less than 15 degrees of curvature, fracture occurred in none of them while deformation was seen in 1(2.4%). There was no difference in K-3 and Protaper files with respect to file deformation and fracture. Most of the fractures occurred in mesiobuccal canals of maxillary molars, n=3(21.4%). The likelihood of file fracture increased 5.65-fold when the same file was used more than 3 times. Irrespective of the rotary system, apical third of the root canal space was the most common site for file fracture.

  18. Influence of multiple clinical use on fatigue resistance of ProTaper rotary nickel-titanium instruments.

    Science.gov (United States)

    Vieira, E P; França, E C; Martins, R C; Buono, V T L; Bahia, M G A

    2008-02-01

    To examine the influence of clinical use on the occurrence of deformation and fracture and on the fatigue resistance of ProTaper rotary instruments. Root canal treatments were performed on patients using the ProTaper rotary system. Ten sets of instruments were used by an experienced endodontist, each set in five molars. Another 10 sets of instruments were used by the same operator, each set in eight molars. In addition, 10 sets of instruments were used, each set in five molars, by undergraduate students with no clinical experience with the system. After clinical use, S1, S2, F1 and F2 instruments were analysed for damage by optical and scanning electron microscopy. The used sets, along with a control group of 12 sets of new instruments, were then tested in a bench device for fatigue resistance. The use of the ProTaper rotary instruments by an experienced endodontist allowed for the cleaning and shaping of the root canal system of up to eight molars without fracture. During the students work, six instruments fractured. Fatigue resistance decreased upon clinical use for all instruments analysed. Fatigue resistance of used instruments was reduced, but no significant change was observed amongst the instruments used for shaping the canals of five and eight molars. Operator experience affected the occurrence of fracture and plastic deformation during shaping.

  19. Effectiveness of Rotary Endodontic Instruments on Smear Layer Removal in Root Canals of Primary Teeth: A Scanning Electron Microscopy Study.

    Science.gov (United States)

    Subramaniam, Priya; Girish Babu, K L; Tabrez, T A

    2016-01-01

    The present SEM study was undertaken to evaluate the effect of root canal instrumentation using both manual and rotary files in the root canals of primary anterior teeth. Thirty freshly extracted primary maxillary incisors were divided into 3 groups of 10 teeth each. In Group I, root canals were instrumented with rotary NiTi files; in Group II, the root canals were instrumented using manual NiTi K files and; in Group III, manual instrumentation was done with stainless steel K files. Longitudinal sections were prepared and processed for observation under SEM at the coronal, middle and apical thirds. Scoring of smear layer was done according to Hulsmann and the data obtained was subjected to statistical analysis. Rotary files cleaned the coronal and middle thirds of root canals more effectively. Statistically there was no significant difference between the groups. Lowest score of 2.6 in the apical third of root canals was seen with hand NiTi files. Rotary instrumentation was as effective as manual instrumentation in removal of smear layer in the root canals of primary anterior teeth.

  20. Influence of curvature location along an artificial canal on cyclic fatigue of a rotary nickel-titanium endodontic instrument.

    Science.gov (United States)

    Lopes, Hélio Pereira; Chiesa, Wanderson Miguel Maia; Correia, Norbi Rodrigues; de Souza Navegante, Núbia Carvalho; Elias, Carlos Nelson; Moreira, Edson Jorge Lima; Chiesa, Bianca Esther Cabral

    2011-06-01

    This study evaluated the effects of curvature location along an artificial canal on cyclic fatigue (CF) of an Mtwo rotary instrument, verifying the number of cycles to fatigue fracture (NCF) and morphologic characteristics of the fractured instruments. CF testing of instruments was performed in artificial canals with curvature radii of 10 mm and arc lengths of 11 mm. Mtwo rotary instruments size 40, 0.04 taper were used in 2 groups (n = 10): group A, curvature positioned on middle part; group B, apical curvature. All instruments were rotated until fracture. The number of cycles to failure was registered. Data were analyzed by independent sample t test. Fractured surfaces and the helical shafts of the instruments were analyzed by scanning electron microscopy. NCF for groups A and B had significant statistic differences (P ductile type. Copyright © 2011 Mosby, Inc. All rights reserved.

  1. Micro-computed tomographic comparison of nickel-titanium rotary versus traditional instruments in C-shaped root canal system.

    Science.gov (United States)

    Yin, Xingzhe; Cheung, Gary Shun-Pan; Zhang, Chengfei; Masuda, Yoshiko Murakami; Kimura, Yuichi; Matsumoto, Koukichi

    2010-04-01

    The purpose of this study was to assess the efficacy of instrumentation of C-shaped canals with ProTaper rotary system and traditional instruments by using micro-computed tomography (micro-CT). Twenty-four mandibular molars with C-shaped canals were selected in pairs and sorted equally into 2 groups, which were assigned for instrumentation by ProTaper rotary system (ProTaper group) or by K-files and Gates-Glidden burs (Hand Instrument group). Three-dimensional images were constructed by micro-CT. The volume of dentin removed, uninstrumented canal area, time taken for instrumentation, and iatrogenic error of instrumentation were investigated. Hand Instrument group showed greater amount of volumetric dentin removal and left less uninstrumented canal area than ProTaper group (P ProTaper group than for Hand Instrument group (P Hand Instrument group than for ProTaper group. It was concluded that ProTaper rotary system maintained the canal curvature with speediness and few procedural errors, whereas traditional instrumentation can clean more canal surface. Copyright (c) 2010 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  2. Effectiveness of supplementary irrigant agitation with the Finisher GF Brush on the debridement of oval root canals instrumented with the Gentlefile or nickel titanium rotary instruments.

    Science.gov (United States)

    Neelakantan, P; Khan, K; Li, K Y; Shetty, H; Xi, W

    2018-07-01

    To examine the efficacy of a novel supplementary irrigant agitating brush (Finisher GF Brush, MedicNRG, Kibbutz Afikim, Israel) on the debridement of root canals prepared with a novel stainless steel rotary instrumentation system (Gentlefile; MedicNRG), or nickel titanium rotary instruments in oval root canals. Mandibular premolars (n = 72) were selected and divided randomly into three experimental groups (n = 24) after microCT scanning: group 1, canal preparation to rotary NiTi size 20, .04 taper (R20); group 2, rotary NiTi to size 25, .04 taper (R25) and group 3, Gentlefile size 23, .04 taper (GF). Specimens were subdivided into two subgroups: subgroup A, syringe-and-needle irrigation (SNI); subgroup B, Finisher GF Brush (GB). Ten untreated canals served as controls. Specimens were processed for histological evaluation, and the remaining pulp tissue (RPT) was measured. Data were analysed using Mann-Whitney and Kruskal-Wallis tests (P = 0.05). All experimental groups had significantly less RPT than the control (P  0.05). When instrumented with R20, there was no significant difference between SNI and GF (P rotary NiTi. Root canal debridement did not significantly differ between the instruments when syringe irrigation was used. © 2018 International Endodontic Journal. Published by John Wiley & Sons Ltd.

  3. Fatigue resistance of rotary ProTaper Universal instruments after use with and without lateral pressure motion

    OpenAIRE

    Vieira, Evandro Pires; Pereira, Érika Sales Joviano; Peixoto, Isabella Faria da Cunha; Buono, Vicente Tadeu Lopes; Bahia, Maria Guiomar de Azevedo

    2016-01-01

    Aim: To evaluate the fatigue resistance of rotary ProTaper Universal instruments after multiple clinical uses with and without lateral pressure motion. Methods: Thirty sets of ProTaper Universal (PTU) instruments (Dentsply-Maillefer, Ballaigues, Switzerland), types S1, S2, F1 and F2, totaling 120 files, were analyzed and divided into three groups, as follows: Control Group (CG), with 10 sets of new instruments, which were fatigue tested until rupture to determine their fatigue resistance; Lat...

  4. Micro-XRD and temperature-modulated DSC investigation of nickel-titanium rotary endodontic instruments.

    Science.gov (United States)

    Alapati, Satish B; Brantley, William A; Iijima, Masahiro; Schricker, Scott R; Nusstein, John M; Li, Uei-Ming; Svec, Timothy A

    2009-10-01

    Employ Micro-X-ray diffraction and temperature-modulated differential scanning calorimetry to investigate microstructural phases, phase transformations, and effects of heat treatment for rotary nickel-titanium instruments. Representative as-received and clinically used ProFile GT and ProTaper instruments were principally studied. Micro-XRD analyses (Cu Kalpha X-rays) were performed at 25 degrees C on areas of approximately 50 microm diameter near the tip and up to 9 mm from the tip. TMDSC analyses were performed from -80 to 100 degrees C and back to -80 degrees C on segments cut from instruments, using a linear heating and cooling rate of 2 degrees C/min, sinusoidal oscillation of 0.318 degrees C, and period of 60s. Instruments were also heat treated 15 min in a nitrogen atmosphere at 400, 500, 600 and 850 degrees C, and analyzed. At all Micro-XRD analysis regions the strongest peak occurred near 42 degrees , indicating that instruments were mostly austenite, with perhaps some R-phase and martensite. Tip and adjacent regions had smallest peak intensities, indicative of greater work hardening, and the intensity at other sites depended on the instrument. TMDSC heating and cooling curves had single peaks for transformations between martensite and austenite. Austenite-finish (A(f)) temperatures and enthalpy changes were similar for as-received and used instruments. Heat treatments at 400, 500 and 600 degrees C raised the A(f) temperature to 45-50 degrees C, and heat treatment at 850 degrees C caused drastic changes in transformation behavior. Micro-XRD provides novel information about NiTi phases at different positions on instruments. TMDSC indicates that heat treatment might yield instruments with substantial martensite and improved clinical performance.

  5. Torsional Performance of ProTaper Gold Rotary Instruments during Shaping of Small Root Canals after 2 Different Glide Path Preparations.

    Science.gov (United States)

    Arias, Ana; de Vasconcelos, Rafaela Andrade; Hernández, Alexis; Peters, Ove A

    2017-03-01

    The purpose of this study was to assess the ex vivo torsional performance of a novel rotary system in small root canals after 2 different glide path preparations. Each independent canal of 8 mesial roots of mandibular molars was randomly assigned to achieve a reproducible glide path with a new set of either PathFile #1 (Dentsply Maillefer, Ballaigues, Switzerland) and #2 or ProGlider (Dentsply Maillefer) after negotiation with a 10 K-file. After glide path preparation, root canals in both groups were shaped with the same sequence of ProTaper Gold (Dentsply Tulsa Dental Specialties, Tulsa, OK) following the directions for use recommended by the manufacturer. A total of 16 new sets of each instrument of the ProTaper Gold (PTG) system were used. The tests were run in a standardized fashion in a torque-testing platform. Peak torque (Ncm) and force (N) were registered during the shaping procedure and compared with Student t tests after normal distribution of data was confirmed. No significant differences were found for any of the instruments in peak torque or force after the 2 different glide path preparations (P > .05). Data presented in this study also serve as a basis for the recommended torque for the use of PTG instruments. Under the conditions of this study, differences in the torsional performance of PTG rotary instruments after 2 different glide path preparations could not be shown. The different geometry of glide path rotary systems seemed to have no effect on peak torque and force induced by PTG rotary instruments when shaping small root canals in extracted teeth. Copyright © 2016 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  6. Reciprocating vs Rotary Instrumentation in Pediatric Endodontics: Cone Beam Computed Tomographic Analysis of Deciduous Root Canals using Two Single-file Systems.

    Science.gov (United States)

    Prabhakar, Attiguppe R; Yavagal, Chandrashekar; Dixit, Kratika; Naik, Saraswathi V

    2016-01-01

    Primary root canals are considered to be most challenging due to their complex anatomy. "Wave one" and "one shape" are single-file systems with reciprocating and rotary motion respectively. The aim of this study was to evaluate and compare dentin thickness, centering ability, canal transportation, and instrumentation time of wave one and one shape files in primary root canals using a cone beam computed tomographic (CBCT) analysis. This is an experimental, in vitro study comparing the two groups. A total of 24 extracted human primary teeth with minimum 7 mm root length were included in the study. Cone beam computed tomographic images were taken before and after the instrumentation for each group. Dentin thickness, centering ability, canal transportation, and instrumentation times were evaluated for each group. A significant difference was found in instrumentation time and canal transportation measures between the two groups. Wave one showed less canal transportation as compared with one shape, and the mean instrumentation time of wave one was significantly less than one shape. Reciprocating single-file systems was found to be faster with much less procedural errors and can hence be recommended for shaping the root canals of primary teeth. How to cite this article: Prabhakar AR, Yavagal C, Dixit K, Naik SV. Reciprocating vs Rotary Instrumentation in Pediatric Endodontics: Cone Beam Computed Tomographic Analysis of Deciduous Root Canals using Two Single-File Systems. Int J Clin Pediatr Dent 2016;9(1):45-49.

  7. Comparison of two techniques for assessing the shaping efficacy of repeatedly used nickel-titanium rotary instruments.

    Science.gov (United States)

    Ounsi, Hani F; Franciosi, Giovanni; Paragliola, Raffaele; Al-Hezaimi, Khalid; Salameh, Ziad; Tay, Franklin R; Ferrari, Marco; Grandini, Simone

    2011-06-01

    The shaping capacity of nickel-titanium (NiTi) rotary instruments is often assessed by photographic or micro-computed tomography (micro-CT) measurements, and these instruments are often used more than once clinically. This study was conducted to compare photographic and micro-CT measurements and to assess if the repeated use of NiTi instruments affected the shape of canal preparation. Ten new sets of ProTaper Universal instruments (Dentsply-Maillefer, Ballaigues, Switzerland) were used in 60 resin blocks simulating curved root canals. Groups 1 to 6 (n=10) represented the first to sixth use of the instrument, respectively. Digitized images of the prepared blocks were taken in both mesiodistal (MD) and buccolingual (BL) directions and area measurements (mm(2)) were calculated using AutoCAD (Autodesk Inc, San Rafael, CA). The volumes of the same prepared canals were measured using micro-CT (mm(3)). Statistical analysis was performed to detect differences between photographic and volumetric measurements and differences between uses. Two-way repeated-measures analysis of variance revealed significant differences between groups (P < .001). Regarding measurement type, there were no significant differences between BL and MD measurements, but there were significant differences between micro-CT and BL measurements (P < .001) and micro-CT and MD measurements (P=.001). Significant differences were also noted between uses. Within the limitations of the present study, micro-CT scanning is more discriminative of the changes in canal space associated with repeated instrument use than photographic measurements. Canal preparations are significantly smaller after the third use of the same instrument. Copyright © 2011 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  8. Effects of liquid- and paste-type EDTA on smear-layer removal during rotary root-canal instrumentation

    Directory of Open Access Journals (Sweden)

    Gin Chen

    2011-03-01

    Conclusions: The use of paste/gel-type chelators during rotary nickel–titanium instrumentation resulted in improved cleanliness in the coronal and middle parts of the root canal. We recommend using liquid EDTA as a final flushing solution during root-canal preparation because it provides a better smear layer-free condition before 3-dimensional root-canal obturation.

  9. Comparison of air-driven vs electric torque control motors on canal centering ability by ProTaper NiTi rotary instruments.

    Science.gov (United States)

    Zarei, Mina; Javidi, Maryam; Erfanian, Mahdi; Lomee, Mahdi; Afkhami, Farzaneh

    2013-01-01

    Cleaning and shaping is one of the most important phases in root canal therapy. Various rotary NiTi systems minimize accidents and facilitate the shaping process. Todays NiTi files are used with air-driven and electric handpieces. This study compared the canal centering after instrumentation using the ProTaper system using Endo IT, electric torque-control motor, and NSK air-driven handpiece. This ex vivo randomized controlled trial study involved 26 mesial mandibular root canals with 10 to 35° curvature. The roots were randomly divided into 2 groups of 13 canals each. The roots were mounted in an endodontic cube with acrylic resin, sectioned horizontally at 2, 6 and 10 mm from the apex and then reassembled. The canals were instrumented according to the manufacturer's instructions using ProTaper rotary files and electric torque-control motors (group 1) or air-driven handpieces (group 2). Photographs of the cross-sections included shots before and after instrumentation, and image analysis was performed using Photoshop software. The centering ability and canal transportation was also evaluated. Repeated measurement and independent t-test provided statistical analysis of canal transportation. The comparison of the rate of transportation toward internal or external walls between the two groups was not statistically significant (p = 0.62). Comparison of the rate of transportation of sections within one group was not significant (p = 0.28). Use of rotary NiTi file with either electric torquecontrol motor or air-driven handpiece had no effect on canal centering. NiTi rotary instruments can be used with air-driven motors without any considerable changes in root canal anatomy, however it needs the clinician to be expert.

  10. In vitro comparison in a manikin model: increasing apical enlargement with K3 and K3XF rotary instruments.

    Science.gov (United States)

    Olivieri, Juan Gonzalo; Stöber, Eva; García Font, Marc; González, Jose Antonio; Bragado, Pablo; Roig, Miguel; Duran-Sindreu, Fernando

    2014-09-01

    The aim of the study was to compare the K3 and K3XF systems (SybronEndo, Glendora, CA) after 1 and 2 uses by evaluating apical transportation, working length loss, and working time in a manikin model. Mesial canals of 40 extracted first mandibular molars were instrumented. Radiographs taken after instrumentation with #25, #30, #35, and #40 files were superimposed on the preoperative image in both mesiodistal and buccolingual angulations. AutoCAD (Autodesk Inc, San Rafael, CA) was used to measure working length loss and apical transportation at 0, 0.5, and 1 mm from the working length (WL). The working time was measured. Group comparison was analyzed using post hoc Tukey honestly significant difference tests (P < .05). No significant differences were found in apical transportation, working length loss between K3 and K3XF systems, or between the number of uses. Significant differences were found when canal enlargement was performed to a #35-40 (P < .05). K3 instrumentation performed significantly faster (29.6 ± 15.4) than with the K3XF system (40.2 ± 17.7) (P < .05). No differences were observed in working time when comparing the number of uses. K3 and R-phase K3XF rotary systems shaped curved root canals safely with minimal apical transportation, even up to a 40/04 file. Copyright © 2014 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  11. Influence of Axial Movement on Fatigue of Profile® Ni-Ti Rotary Instruments: an in vitro evaluation

    Directory of Open Access Journals (Sweden)

    Marie-Chantal Avoaka

    2010-05-01

    Full Text Available The aim of this study was to evaluate the influence of the axial movement and the angle of curve (in degrees on fatigue of nickel-titanium (Ni-Ti ProFile’ rotary endodontic instruments.Ni-Ti ProFile’ rotary instruments (Maillefer SA, Ballaigues, Switzerland, 25 mm long in the range of ISO size 15 to 40 with two tapers (0.4 and 0.6 were evaluated. They are divided in two groups: the instruments with axial movement and those without axial movement. The system used to test the fatigue is maintained in mechanical conditions as close as possible to the clinical situation. The axial movement is in the order of 2mm in corono-apical direction with a frequency of 1Hz. The concave radii incorporating a notched V-form for guiding the instruments were: 5; 7,5 and 10 mm. The rotary system is mounted on an electric handpiece and rotated at 350 rpm speed as recommended by the manufacturers. The instruments are rotated until their separation, and the time, in seconds, is recorded. Statístícal evaluation is undertaken using a two-way t-test to identify significant differences between variables in the study (p <0,05.We found significant statistical difference (p<0,05 between Ni-Ti engine drive ProFile’ instruments incorporating an axial movement and the instruments without axial movement with the same radius of curvature, size and taper.The incorporation of the axial movement increases significantly the life-span of the ProFile’ rotary instruments. This should reduce the risk of the instrument separation during the endodontic treatment

  12. Influence of axial movement on fatigue of ProFile Ni-Ti rotary instruments: an in vitro evaluation.

    Science.gov (United States)

    Avoaka, Marie-Chantal; Haïkel, Youssef

    2010-05-01

    The aim of this study was to evaluate the influence of the axial movement and the angle of curve (in degrees) on fatigue of nickel-titanium (Ni-Ti) ProFile rotary endodontic instruments. Ni-Ti ProFile rotary instruments (Maillefer SA, Ballaigues, Switzerland), 25 mm long in the range of ISO size 15 to 40 with two tapers (0.4 and 0.6) were evaluated. They are divided in two groups: the instruments with axial movement and those without axial movement. The system used to test the fatigue is maintained in mechanical conditions as close as possible to the clinical situation. The axial movement is in the order of 2 mm in corono-apical direction with a frequency of 1 Hz. The concave radii incorporating a notched V-form for guiding the instruments were: 5; 7,5 and 10 mm. The rotary system is mounted on an electric handpiece and rotated at 350 rpm speed as recommended by the manufacturers. The instruments are rotated until their separation, and the time, in seconds, is recorded. Statistical evaluation is undertaken using a two-way t-test to identify significant differences between variables in the study (p engine drive ProFile instruments incorporating an axial movement and the instruments without axial movement with the same radius of curvature, size and taper.The incorporation of the axial movement increases significantly the life-span of the ProFile rotary instruments. This should reduce the risk of the instrument separation during the endodontic treatment.

  13. Influence of axial movement on fatigue of PROFILE* NI-TI rotary instruments: an in vitro evaluation

    Science.gov (United States)

    Avoaka, Marie-Chantal; Haïkel, Youssef

    2010-01-01

    The aim of this study was to evaluate the influence of the axial movement and the angle of curve (in degrees) on fatigue of nickel-titanium (Ni-Ti) ProFile’ rotary endodontic instruments. Ni-Ti ProFile’ rotary instruments (Maillefer SA, Ballaigues, Switzerland), 25 mm long in the range of ISO size 15 to 40 with two tapers (0.4 and 0.6) were evaluated. They are divided in two groups: the instruments with axial movement and those without axial movement. The system used to test the fatigue is maintained in mechanical conditions as close as possible to the clinical situation. The axial movement is in the order of 2mm in corono-apical direction with a frequency of 1Hz. The concave radii incorporating a notched V-form for guiding the instruments were: 5; 7,5 and 10 mm. The rotary system is mounted on an electric handpiece and rotated at 350 rpm speed as recommended by the manufacturers. The instruments are rotated until their separation, and the time, in seconds, is recorded. Statístícal evaluation is undertaken using a two-way t-test to identify significant differences between variables in the study (p engine drive ProFile’ instruments incorporating an axial movement and the instruments without axial movement with the same radius of curvature, size and taper. The incorporation of the axial movement increases significantly the life-span of the ProFile’ rotary instruments. This should reduce the risk of the instrument separation during the endodontic treatment. PMID:20507289

  14. Comparative evaluation of apical extrusion of bacteria using hand and rotary systems : An in vitro study

    Science.gov (United States)

    Ghivari, Sheetal B; Kubasad, Girish C; Deshpande, Preethi

    2012-01-01

    Aim: To evaluate the bacteria extruded apically during root canal preparation using two hand and rotary instrumentation techniques. Materials and Methods: Eighty freshly extracted mandibular premolars were mounted in bacteria collection apparatus. Root canals were contaminated with the pure culture of Enterococcus fecalis (ATCC 29212) and dried at 37°C for 24 h. Bacteria extruded were collected, incubated in brain heart infusion agar for 24 h at 36°C and the colony forming units (CFU) were counted. Statistical Analysis: The mean number of colony forming units were calculated by One-way ANOVA and comparison between the groups made by multiple comparison (Dunnet D) test. Results: The step-back technique extruded highest number of bacteria in comparison to other hand and rotary Ni–Ti systems. Conclusion: Under the limitation of this study all hand and rotary instrumentation techniques extruded bacteria. Among all the instrumentation techniques step-back technique extruded more number of bacteria and K-3 system the least. Further in vivo research in this direction could provide more insight into the biologic factors associated and focus on bacterial species that essentially play a major role in post instrumentation flare-ups. PMID:22368332

  15. Apically extruded debris with three contemporary Ni-Ti instrumentation systems: an ex vivo comparative study.

    Science.gov (United States)

    Logani, Ajay; Shah, Naseem

    2008-01-01

    To comparatively evaluate the amount of apically extruded debris when ProTaper hand, ProTaper rotary and ProFile systems were used for the instrumentation of root canals. Thirty minimally curved, mature, human mandibular premolars with single canals were randomly divided into three groups of ten teeth each. Each group was instrumented using one of the three instrumentation systems: ProTaper hand, ProTaper rotary and ProFile. Five milliliters of sterile water were used as an irrigant. Debris extruded was collected in preweighed polyethylene vials and the extruded irrigant was evaporated. The weight of the dry extruded debris was established by comparing the pre- and postinstrumentation weight of polyethylene vials for each group. The Kruskal-Wallis nonparametric test and Mann-Whitney U test were applied to determine if significant differences existed among the groups ( PProTaper hand and ProFile system ( P > 0.05). Although ProTaper rotary extruded a relatively higher amount of debris, no statistically significant difference was observed between this type and the ProTaper hand instruments ( P > 0.05). The ProTaper rotary extruded significantly more amount of debris compared to the ProFile system ( PProTaper rotary extruded a significantly higher amount of debris than the ProFile.

  16. Efficacy of NiTi rotary instruments in removing calcium hydroxide dressing residues from root canal walls

    Directory of Open Access Journals (Sweden)

    Milton Carlos Kuga

    2012-02-01

    Full Text Available The aim of this study was to evaluate the efficacy of three rotary instrument systems (K3, ProTaper and Twisted File in removing calcium hydroxide residues from root canal walls. Thirty-four human mandibular incisors were instrumented with the ProTaper System up to the F2 instrument, irrigated with 2.5% NaOCl followed by 17% EDTA, and filled with a calcium hydroxide intracanal dressing. After 7 days, the calcium hydroxide dressing was removed using the following rotary instruments: G1 - NiTi size 25, 0.06 taper, of the K3 System; G2 - NiTi F2, of the ProTaper System; or G3 - NiTi size 25, 0.06 taper, of the Twisted File System. The teeth were longitudinally grooved on the buccal and lingual root surfaces, split along their long axis, and their apical and cervical canal thirds were evaluated by SEM (×1000. The images were scored and the data were statistically analyzed using the Kruskall Wallis test. None of the instruments removed the calcium hydroxide dressing completely, either in the apical or cervical thirds, and no significant differences were observed among the rotary instruments tested (p > 0.05.

  17. Postoperative Pain after Endodontic Retreatment Using Rotary or Reciprocating Instruments: A Randomized Clinical Trial.

    Science.gov (United States)

    Comparin, Daniel; Moreira, Edson Jorge Lima; Souza, Erick M; De-Deus, Gustavo; Arias, Ana; Silva, Emmanuel João Nogueira Leal

    2017-07-01

    The aim of this randomized clinical trial was to evaluate the influence of rotary or reciprocating retreatment techniques on the incidence, intensity, duration of postoperative pain, and medication intake. After power analysis calculations, 65 patients who needed endodontic retreatment were randomly assigned to 1 of 2 groups according to the instrumentation system used: Mtwo (VDW, Munich, Germany) or Reciproc (VDW). Retreatments were performed in a single visit by an endodontic specialist. Participants were asked to rate the incidence and intensity of the postoperative pain on a verbal rating scale 24, 48, and 72 hours after treatment. Patients were also asked to record the number of prescribed analgesic medication tablets (ibuprofen 400 mg) taken. A logistic regression analysis was used to assess both the incidence and duration of pain. Differences in the intensity of pain were analyzed using the ordinal (linear) chi-square test, and the Mann-Whitney U test was used to assess differences in the intake of analgesic medication between groups. No statistically significant difference was found among the 2 groups in relation to postoperative pain or analgesic medication intake at the 3 time points assessed (P > .05). Multivariate analysis showed a significantly higher incidence of pain after 24 hours when preoperative pain was present and a significantly longer duration of pain for men than women independently of the retreatment technique used. The reciprocating system and the continuous rotary system were found to be equivalent regarding the incidence, intensity, duration of postoperative pain, and intake of analgesic medication. Copyright © 2017 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  18. Evaluation of cyclic flexural fatigue of M-wire nickel-titanium rotary instruments.

    Science.gov (United States)

    Al-Hadlaq, Solaiman M S; Aljarbou, Fahad A; AlThumairy, Riyadh I

    2010-02-01

    This study was conducted to investigate cyclic flexural fatigue resistance of GT series X rotary files made from the newly developed M-wire nickel-titanium alloy compared with GT and Profile nickel-titanium files made from a conventional nickel-titanium alloy. Fifteen files, size 30/0.04, of each type were used to evaluate the cyclic flexural fatigue resistance. A simple device was specifically constructed to measure the time each file type required to fail under cyclic flexural fatigue testing. The results of this experiment indicated that the GT series X files had superior cyclic flexural fatigue resistance than the other 2 file types made from a conventional nickel-titanium alloy (P = .004). On the other hand, the difference between the Profile and the GT files was not statistically significant. The findings of this study suggest that size 30/0.04 nickel-titanium rotary files made from the newly developed M-wire alloy have better cyclic flexural fatigue resistance than files of similar design and size made from the conventional nickel-titanium alloy. Copyright 2010 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  19. Dental students' perceptions about the endodontic treatments performed using NiTi rotary instruments and hand stainless steel files.

    Science.gov (United States)

    Martins, Renata Castro; Seijo, Marília Oliveira Saraiva; Ferreira, Efigênia Ferreira; Paiva, Saul Martins; Ribeiro Sobrinho, Antônio Paulino

    2012-01-01

    This study evaluated the perceptions of Brazilian undergraduate dental students about the endodontic treatments performed using NiTi rotary instruments and hand stainless steel. Data were collected using a questionnaire administered to undergraduate dental students enrolled in endodontic disciplines. The students were divided into 3 groups: G1, students who had treated straight canals with SS hand instruments; G2, students who had treated curved canals with SS hand instruments; and G3, students who had treated both straight and curved canals with NiTi rotary instruments. The number of endodontic treatments performed, types of treated teeth, students' learning, time spent, encountered difficulties, quality of endodontic treatment and characteristics of the employed technique were analyzed. There was a 91.3% rate of return for the questionnaires. Mandibular molars were the most frequently treated teeth, followed by maxillary incisors. The Kruskal-Wallis test showed no differences in learning (p=0.528) or in the characteristics of the technique employed (p=0.560) among the three groups. G3 students performed a greater number of endodontic treatments (pendodontic treatments differed only between G1 and G2 (p=0.045). The use of NiTi rotary instruments should be included in undergraduate dental curriculum, contributing to the increase of patients assisted and consequently to improve the clinical experience of the students.

  20. Cone-beam computed tomography analysis of curved root canals after mechanical preparation with three nickel-titanium rotary instruments

    Science.gov (United States)

    Elsherief, Samia M.; Zayet, Mohamed K.; Hamouda, Ibrahim M.

    2013-01-01

    Cone beam computed tomography is a 3-dimensional high resolution imaging method. The purpose of this study was to compare the effects of 3 different NiTi rotary instruments used to prepare curved root canals on the final shape of the curved canals and total amount of root canal transportation by using cone-beam computed tomography. A total of 81 mesial root canals from 42 extracted human mandibular molars, with a curvature ranging from 15 to 45 degrees, were selected. Canals were randomly divided into 3 groups of 27 each. After preparation with Protaper, Revo-S and Hero Shaper, the amount of transportation and centering ability that occurred were assessed by using cone beam computed tomography. Utilizing pre- and post-instrumentation radiographs, straightening of the canal curvatures was determined with a computer image analysis program. Canals were metrically assessed for changes (surface area, changes in curvature and transportation) during canal preparation by using software SimPlant; instrument failures were also recorded. Mean total widths and outer and inner width measurements were determined on each central canal path and differences were statistically analyzed. The results showed that all instruments maintained the original canal curvature well with no significant differences between the different files (P = 0.226). During preparation there was failure of only one file (the protaper group). In conclusion, under the conditions of this study, all instruments maintained the original canal curvature well and were safe to use. Areas of uninstrumented root canal wall were left in all regions using the various systems. PMID:23885273

  1. Quantitative assessment of apical debris extrusion and intracanal debris in the apical third, using hand instrumentation and three rotary instrumentation systems.

    Science.gov (United States)

    H K, Sowmya; T S, Subhash; Goel, Beena Rani; T N, Nandini; Bhandi, Shilpa H

    2014-02-01

    Decreased apical extrusion of debris and apical one third debris have strong implications for decreased incidence of postoperative inflammation and pain. Thus, the aim of this study was to assess quantitatively the apical extrusion of debris and intracanal debris in the apical third during root canal instrumentation using hand and three different types of rotary instruments. Sixty freshly extracted single rooted human teeth were randomly divided into four groups. Canal preparation was done using step-back with hand instrumentation, crown-down technique with respect to ProTaper and K3, and hybrid technique with LightSpeed LSX. Irrigation was done with NaOCl, EDTA, and normal saline and for final irrigation, EndoVac system was used. The apically extruded debris was collected on the pre-weighed Millipore plastic filter disk and weighed using microbalance. The teeth were submitted to the histological processing. Sections from the apical third were analyzed by a trinocular research microscope that was coupled to a computer where the images were captured and analyzed using image proplus V4.1.0.0 software. The mean weight of extruded debris for each group and intracanal debris in the root canal was statistically analyzed by a Kruskal-Wallis one-way analysis of variance and Mann-Whitney U test. The result showed that, hand instrumentation using K files showed the highest amount of debris extrusion apically when compared to ProTaper, K3 and LightSpeed LSX. The result also showed that there was no statistically significant difference between the groups in relation to presence of intracanal debris in the apical one third. Based on the results, all instrumentation techniques produced debris extrusion. The engine driven Ni-Ti systems extruded significantly less apical debris than hand instrumentation. There was no statistically significant difference between the groups in relation to presence of intracanal debris in the apical one third.

  2. Chemomechanical preparation by hand instrumentation and by Mtwo engine-driven rotary files, an ex vivo study.

    Science.gov (United States)

    Krajczár, Károly; Tigyi, Zoltán; Papp, Viktória; Marada, Gyula; Sára, Jeges; Tóth, Vilmos

    2012-07-01

    To compare the disinfecting efficacy of the sodium hypochlorite irrigation by root canal preparation with stainless steel hand files, taper 0.02 and nickel-titanium Mtwo files with taper 0.04-0.06. 40 extracted human teeth were sterilized, and then inoculated with Enterococcus faecalis (ATCC 29212). After 6 day incubation time the root canals were prepared by hand with K-files (n=20) and by engine-driven Mtwo files (VDW, Munich, Germany) (n=20). Irrigation was carried out with 2.5% NaOCl in both cases. Samples were taken and determined in colony forming units (CFU) from the root canals before and after the preparation with instruments #25 and #35. Significant reduction in bacterial count was determined after filing at both groups. The number of bacteria kept on decreasing with the extension of apical preparation diameter. There was no significant difference between the preparation sizes in the bacterial counts after hand or engine-driven instrumentation at the same apical size. Statistical analysis was carried out with Mann-Whitney test, paired t-test and independent sample t-test. Significant reduction in CFU was achieved after the root canal preparation completed with 2.5% NaOCl irrigation, both with stainless steel hand or nickel-titanium rotary files. The root canal remained slightly infected after chemo mechanical preparation in both groups. Key words:Chemomechanical preparation, root canal disinfection, nickel-titanium, conicity, greater taper, apical size.

  3. Stereomicroscopic evaluation of defects caused by torsional fatigue in used hand and rotary nickel-titanium instruments.

    Science.gov (United States)

    Asthana, Geeta; Kapadwala, Marsrat I; Parmar, Girish J

    2016-01-01

    The aim of this study was to evaluate defects caused by torsional fatigue in used hand and rotary nickel-titanium (Ni-Ti) instruments by stereomicroscopic examination. One hundred five greater taper Ni-Ti instruments were used including Protaper universal hand (Dentsply Maillefer, Ballaigues, Switzerland), Protaper universal rotary (Dentsply Maillefer, Ballaigues, Switzerland), and Revo-S rotary (MicroMega, Besançon, France) files. Files were used on lower anterior teeth. After every use, the files were observed with both naked eyes and stereomicroscope at 20× magnification (Olympus, Shinjuku, Tokyo, Japan) to evaluate defects caused by torsional fatigue. Scoring was assigned to each file according to the degree of damage. The results were statistically analyzed using the Mann-Whitney U test and the Kruskal-Wallis test. A greater number of defects were seen under the stereomicroscope than on examining with naked eyes. However, the difference in methods of evaluation was not statistically significant. Revo-S files showed minimum defects, while Protaper universal hand showed maximum defects. The intergroup comparison of defects showed that the bend in Protaper universal hand instruments was statistically significant. Visible defects in Ni-Ti files due to torsional fatigue were seen by naked eyes as well as by stereomicroscope. This study emphasizes that all the files should be observed before and after every instrument cycle to minimize the risk of separation.

  4. Torsion and bending properties of shape memory and superelastic nickel-titanium rotary instruments.

    Science.gov (United States)

    Ninan, Elizabeth; Berzins, David W

    2013-01-01

    Recently introduced into the market are shape memory nickel-titanium (NiTi) rotary files. The objective of this study was to investigate the torsion and bending properties of shape memory files (CM Wire, HyFlex CM, and Phoenix Flex) and compare them with conventional (ProFile ISO and K3) and M-Wire (GT Series X and ProFile Vortex) NiTi files. Sizes 20, 30, and 40 (n = 12/size/taper) of 0.02 taper CM Wire, Phoenix Flex, K3, and ProFile ISO and 0.04 taper HyFlex CM, ProFile ISO, GT Series X, and Vortex were tested in torsion and bending per ISO 3630-1 guidelines by using a torsiometer. All data were statistically analyzed by analysis of variance and the Tukey-Kramer test (P = .05) to determine any significant differences between the files. Significant interactions were present among factors of size and file. Variability in maximum torque values was noted among the shape memory files brands, sometimes exhibiting the greatest or least torque depending on brand, size, and taper. In general, the shape memory files showed a high angle of rotation before fracture but were not statistically different from some of the other files. However, the shape memory files were more flexible, as evidenced by significantly lower bending moments (P < .008). Shape memory files show greater flexibility compared with several other NiTi rotary file brands. Copyright © 2013 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  5. Cyclic fatigue resistances of several nickel-titanium glide path rotary and reciprocating instruments at body temperature.

    Science.gov (United States)

    Yılmaz, K; Uslu, G; Gündoğar, M; Özyürek, T; Grande, N M; Plotino, G

    2018-01-31

    To compare the cyclic fatigue resistance of the One G, ProGlider, HyFlex EDM and R-Pilot glide path NiTi files at body temperature. Twenty One G (size 14, .03 taper), 20 ProGlider (size 16, .02 taper), 20 HyFlex EDM (size 10, .05 taper) and 20 R-Pilot (size 12.5, .04 taper) instruments were operated in rotation at 300 rpm (One G, ProGlider and HyFlex) or in reciprocation (R-Pilot) at 35 °C in artificial canals that were manufactured by reproducing the size and taper of the instrument until fracture occurred. The time to fracture was recorded in seconds using a digital chronometer, and the length of the fractured fragments was registered. Mean data were analysed statistically using the Kruskal-Wallis test and post hoc Tukey tests via SPSS 21.0 software. The statistical significance level was set at 5%. The cyclic fatigue resistance of the R-Pilot files was significantly greater than the other instruments, and the One G was significantly lower (P EDM and the ProGlider (P > 0.05). No significant difference (P > 0.05) was evident in the mean length of the fractured fragments of the various instruments. The cyclic fatigue resistance of the R-Pilot reciprocating glide path file was significantly greater than that of the rotary HyFlex EDM, ProGlider and One G glide path files. © 2018 International Endodontic Journal. Published by John Wiley & Sons Ltd.

  6. Efficacy of reciprocating and rotary NiTi instruments for retreatment of curved root canals assessed by micro-CT.

    Science.gov (United States)

    Rödig, T; Reicherts, P; Konietschke, F; Dullin, C; Hahn, W; Hülsmann, M

    2014-10-01

    To compare the efficacy of reciprocating and rotary NiTi-instruments in removing filling material from curved root canals using micro-computed tomography. Sixty curved root canals were prepared and filled with gutta-percha and sealer. After determination of root canal curvatures and radii in two directions as well as volumes of filling material, the teeth were assigned to three comparable groups (n = 20). Retreatment was performed using Reciproc, ProTaper Universal Retreatment or Hedström files. Percentages of residual filling material and dentine removal were assessed using micro-CT imaging. Working time and procedural errors were recorded. Statistical analysis was performed by variance procedures. No significant differences amongst the three retreatment techniques concerning residual filling material were detected (P > 0.05). Hedström files removed significantly more dentine than ProTaper Universal Retreatment (P  0.05). Reciproc and ProTaper Universal Retreatment were significantly faster than Hedström files (P = 0.0001). No procedural errors such as instrument fracture, blockage, ledging or perforation were detected for Hedström files. Three perforations were recorded for ProTaper Universal Retreatment, and in both NiTi groups, one instrument fracture occured. Remnants of filling material were observed in all samples with no significant differences between the three techniques. Hedström files removed significantly more dentine than ProTaper Universal Retreatment, but no significant differences between both NiTi systems were detected. Procedural errors were observed with ProTaper Universal Retreatment and Reciproc. © 2014 International Endodontic Journal. Published by John Wiley & Sons Ltd.

  7. Correlation between Temperature-dependent Fatigue Resistance and Differential Scanning Calorimetry Analysis for 2 Contemporary Rotary Instruments.

    Science.gov (United States)

    Arias, Ana; Macorra, José C; Govindjee, Sanjay; Peters, Ove A

    2018-04-01

    The aim of this study was to assess differences in cyclic fatigue (CF) life of contemporary heat-treated nickel-titanium rotary instruments at room and body temperatures and to document corresponding phase transformations. Forty Hyflex EDM (H-EDM) files (Coltene, Cuyahoga Falls, OH [#25/.08, manufactured by electrical discharge machining]) and 40 TRUShape (TS) files (Dentsply Tulsa Dental Specialties, Tulsa, OK [#25/.06v, manufactured by grinding and shape setting]) were divided into 2 groups (n = 20) for CF resistance tests in a water bath either at room (22°C ± 0.5°C) or body temperature (37°C ± 0.5°C). Instruments were rotated in a simulated canal (angle = 60°, radius = 3 mm, and center of the curvature 5 mm from the tip) until fracture occurred. The motor was controlled by an electric circuit that was interrupted after instrument fracture. The mean half-life and beta and eta Weibull parameters were determined and compared. Two instruments of each brand were subjected to differential scanning calorimetry (DSC). While TS instruments lasted significantly longer at room temperature (mean life = 234.7 seconds; 95% confidence interval [CI], 209-263.6) than at body temperature (mean life = 83.2 seconds; 95% CI, 76-91.1), temperature did not affect H-EDM behavior (room temperature mean life = 725.4 seconds; 95% CI, 658.8-798.8 and body temperature mean life = 717.9 seconds; 95% CI, 636.8-809.3). H-EDM instruments significantly outlasted TS instruments at both temperatures. At body temperature, TS was predominantly austenitic, whereas H-EDM was martensitic or in R-phase. TS was in a mixed austenitic/martensitic phase at 22°C, whereas H-EDM was in the same state as at 37°C. H-EDM had a longer fatigue life than TS, which showed a marked decrease in fatigue life at body temperature; neither the life span nor the state of the microstructure in the DSC differed for H-EDM between room or body temperature. Copyright © 2017 American Association of

  8. Comparison of the cyclic fatigue resistance of 5 different rotary pathfinding instruments made of conventional nickel-titanium wire, M-wire, and controlled memory wire.

    Science.gov (United States)

    Capar, Ismail Davut; Kaval, Mehmet Emin; Ertas, Hüseyin; Sen, Bilge Hakan

    2015-04-01

    This study compared the cyclic fatigue resistance of current nickel-titanium rotary path-finding instruments. Five types of nickel-titanium rotary pathfinding instruments were used in steel canals with a 90° curvature and a curvature radius of 3 mm (n = 10) and 5 mm (n = 10). The cyclic fatigue of the following instruments was tested at 4 mm from the tip: PathFile (#16 and a .02 taper; Dentsply Maillefer, Ballaigues, Switzerland), G-File (#12 and a .03 taper; Micro-Mega, Besançon Cedex, France), Scout Race (#15 and a .02 taper; FKG Dentaire, La Chaux-de-Fonds, Switzerland), HyFlex GPF (#15 and a .02 taper; Coltene-Whaledent, Allstetten, Switzerland), and ProGlider (#16 with a mean taper of .04125 and a .02 at the first 4 mm from the tip, Dentsply Maillefer). The length of the fractured parts was measured, and the number of cycles to fracture (NCF) was calculated. The data were statistically analyzed using Kruskal-Wallis and Mann-Whitney tests (α = .05). After Bonferroni correction, the new P value was set as .005. The difference in the cyclic fatigue of all the files at both curvatures was statistically significant (P values from .0035 to less than .0001). The ranking of the instruments from the highest to the lowest NCF was as follows: HyFlex GPF, G files, ProGlider, PathFile, and Scout Race. The length of the fractured part of the instruments was similar in all the groups (P > .05). All the tested instruments had a lower NCF at a curvature radius of 3 mm when compared with a curvature radius of 5 mm (P instrument was the highest, and the curvature radius had a significant effect on the fatigue resistance. Copyright © 2015 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  9. Mechanical properties of ProTaper Gold nickel-titanium rotary instruments.

    Science.gov (United States)

    Elnaghy, A M; Elsaka, S E

    2016-11-01

    To evaluate and compare the resistance to cyclic fatigue and torsional stress, flexibility and surface microhardness of ProTaper Gold (PTG; Dentsply, Tulsa Dental Specialties, Tulsa, OK, USA) system with ProTaper Universal (PTU; Dentsply Maillefer, Ballaigues, Switzerland). PTG and PTU instruments were rotated in simulated canals and the number of cycles to failure was recorded to assess their cyclic fatigue resistance. Torsional strength was measured using a torsiometer after fixing firmly the apical 3 mm of the instrument. A scanning electron microscope was used to characterize the topographic features of the fracture surfaces of the broken instruments. The instruments were tested for bending resistance using cantilever-bending test. Vickers microhardness was measured on the cross section of instruments with 300 g load and 15 s dwell time. Data were analysed statistically using independent t-tests. Statistical significance was set at P hand, PTU instruments were associated with higher resistance to torsional stress and microhardness than PTG instruments (P < 0.001). After torsional tests, the fractured cross-sectional surfaces revealed skewed dimples near the centre of the fracture surfaces and circular abrasion streaks. The PTG instrument had improved resistance to cyclic fatigue and flexibility compared with PTU. PTU instruments had improved resistance to torsional stress and microhardness compared with PTG. © 2015 International Endodontic Journal. Published by John Wiley & Sons Ltd.

  10. Assessment of postoperative pain after reciprocating or rotary NiTi instrumentation of root canals: a randomized, controlled clinical trial.

    Science.gov (United States)

    Relvas, João Bosko Formigas; Bastos, Mariana Mena Barreto; Marques, André Augusto Franco; Garrido, Angela Delfina Bitencourt; Sponchiado, Emílio Carlos

    2016-11-01

    The aim of this study was to assess postoperative pain in a prospective randomized clinical trial comparing two groups, using the Reciproc® system in one group and the ProTaper® rotary system in the other. The study included 78 male patients, aged 18-64 years (mean age of 26 years), with asymptomatic pulp necrosis in mandibular molar teeth (n = 78). The single-session endodontic treatment was performed by a single operator specialized in Endodontics. Mechanical preparation of the root canals was performed using the ProTaper® and Reciproc® instrumentation techniques. Postoperative pain was recorded using a verbal rating scale (VRS) and verbal description with well-defined categories at the three following time intervals: 24 h, 72 h, and 7 days after the endodontic procedure. The assessment of postoperative pain was recorded as no pain, mild pain, moderate pain, and severe pain or flare-up. Data were analyzed using the nonparametric Mann-Whitney test with the aid of the STATA® software. The incidence of postoperative pain in the ProTaper group (PT) 24 h after the endodontic procedure was 17.9 and 5.1 % after 72 h. In the Reciproc group (RP), the incidence after 24 h was 15.3 and 2.5 % after 72 h. No patients presented severe pain at the time intervals assessed. No significant difference (p > 0.05) in postoperative pain was found between the ProTaper® and Reciproc® instrumentation technique during endodontic treatment in this study. According to our findings and the results of the clinical trial, the occurrence of postoperative pain was low and similar between the reciprocating and rotary techniques during the time intervals assessed. These results are different from basic laboratory studies that affirm that the reciprocating techniques tend to promote more postoperative pain since extrusion of debris is greater.

  11. Apically extruded debris with three contemporary Ni-Ti instrumentation systems: An ex vivo comparative study

    Directory of Open Access Journals (Sweden)

    Logani Ajay

    2008-01-01

    Full Text Available Aim: To comparatively evaluate the amount of apically extruded debris when ProTaper hand, ProTaper rotary and ProFile systems were used for the instrumentation of root canals. Materials and Methods: Thirty minimally curved, mature, human mandibular premolars with single canals were randomly divided into three groups of ten teeth each. Each group was instrumented using one of the three instrumentation systems: ProTaper hand, ProTaper rotary and ProFile. Five milliliters of sterile water were used as an irrigant. Debris extruded was collected in preweighed polyethylene vials and the extruded irrigant was evaporated. The weight of the dry extruded debris was established by comparing the pre- and postinstrumentation weight of polyethylene vials for each group. Statistical Analysis: The Kruskal-Wallis nonparametric test and Mann-Whitney U test were applied to determine if significant differences existed among the groups ( P < 0.05. Results: All instruments tested produced a measurable amount of debris. No statistically significant difference was observed between ProTaper hand and ProFile system ( P > 0.05. Although ProTaper rotary extruded a relatively higher amount of debris, no statistically significant difference was observed between this type and the ProTaper hand instruments ( P > 0.05. The ProTaper rotary extruded significantly more amount of debris compared to the ProFile system ( P < 0.05. Conclusion: Within the limitations of this study, it can be concluded that all instruments tested produced apical extrusion of debris. The ProTaper rotary extruded a significantly higher amount of debris than the ProFile.

  12. Shaping ability of NT Engine and McXim rotary nickel-titanium instruments in simulated root canals. Part 1.

    Science.gov (United States)

    Thompson, S A; Dummer, P M

    1997-07-01

    The aim of this study was to determine the shaping ability of NT Engine and McXim nickel-titanium rotary instruments in simulated root canals. In all, 40 canals consisting of four different shapes in terms of angle and position of curvature were prepared by a combination of NT Engine and McXim instruments using the technique recommended by the manufacturer. Part 1 of this two-part report describes the efficacy of the instruments in terms of preparation time, instrument failure, canal blockages, loss of canal length and three-dimensional canal form. Overall, the mean preparation time for all canals was 6.01 min, with canal shape having a significant effect (P Engine and McXim instruments prepared canals rapidly, with few deformations, no canal blockages and with minimal change in working length. The three-dimensional form of the canals demonstrated good flow and taper characteristics.

  13. To evaluate and compare the efficacy, cleaning ability of hand and two rotary systems in root canal retreatment.

    Science.gov (United States)

    Shivanand, Sunita; Patil, Chetan R; Thangala, Venugopal; Kumar, Pabbati Ravi; Sachdeva, Jyoti; Krishna, Akash

    2013-05-01

    To evaluate and compare the efficacy, cleaning ability of hand and two rotary systems in root canal retreatment. Sixty extracted premolars were retreated with following systems: Group -ProTaper Universal retreatment files, Group 2-ProFile system, Group 3-H-file. Specimens were split longitudinally and amount of remaining gutta-percha on the canal walls was assessed using direct visual scoring with the aid of stereomicroscope. Results were statistically analyzed using ANOVA test. Completely clean root canal walls were not achieved with any of the techniques investigated. However, all three systems proved to be effective for gutta-percha removal. Significant difference was found between ProTaper universal retreatment file and H-file, and also between ProFile and H-file. Under the conditions of the present study, ProTaper Universal retreatment files left significantly less guttapercha and sealer than ProFile and H-file. Rotary systems in combination with gutta-percha solvents can perform superiorly as compared to the time tested traditional hand instrumentation in root canal retreatment.

  14. Physical and mechanical properties of a thermomechanically treated NiTi wire used in the manufacture of rotary endodontic instruments.

    Science.gov (United States)

    Pereira, E S J; Peixoto, I F C; Viana, A C D; Oliveira, I I; Gonzalez, B M; Buono, V T L; Bahia, M G A

    2012-05-01

    To compare physical and mechanical properties of one conventional and one thermomechanically treated nickel-titanium (NiTi) wire used to manufacture rotary endodontic instruments. Two NiTi wires 1.0 mm in diameter were characterized; one of them, C-wire (CW), was processed in the conventional manner, and the other, termed M-Wire (MW), received an additional heat treatment according to the manufacturer. Chemical composition was determined by energy-dispersive X-ray spectroscopy, phase constitution by XRD and the transformation temperatures by DSC. Tensile loading/unloading tests and Vickers microhardness measurements were performed to assess the mechanical behaviour. Data were analysed using analysis of variance (α = 0.05). The two wires showed approximately the same chemical composition, close to the 1 : 1 atomic ratio, and the β-phase was the predominant phase present. B19' martensite and the R-phase were found in MW, in agreement with the higher transformation temperatures found in this wire compared with CW, whose transformation temperatures were below room temperature. Average Vickers microhardness values were similar for MW and CW (P = 0.91). The stress at the transformation plateau in the tensile load-unload curves was lower and more uniform in the M-Wire, which also showed the smallest stress hysteresis and apparent elastic modulus. The M-Wire had physical and mechanical properties that can render endodontic instruments more flexible and fatigue resistant than those made with conventionally processed NiTi wires. © 2011 International Endodontic Journal.

  15. [The influence of autoclave sterilization on surface characteristics and cyclic fatigue resistance of 3 nickel-titanium rotary instruments].

    Science.gov (United States)

    Li, Xiang-fen; Zheng, Ping; Xu, Li; Su, Qin

    2015-12-01

    To investigate the effects of autoclave sterilization on surface characteristics and cyclic fatigue resistance of 3 types of nickel-titanium rotary instruments (K3, Mtwo, ProTaper). Three brands of NiTi rotary endodontic instruments of the same size (tip diameter 0.25 mm and constant 0.06 taper) were selected: K3, Mtwo and Protaper (F2). 24 instruments for each brand were used to evaluate the effects of autoclave sterilization on inner character in the as-received condition and after subjection to 0, 1, 5, and 10 sterilization cycles (6 for each group). Time to fracture (TtF) from the start of the test to the moment of file breakage and the length of the fractured fragment were recorded. Means and standard deviations of TtF and fragment length were calculated. The data was analyzed with SPSS13.0 software package. Another 12 NiTi rotary instruments for each brand were used, 6 subjected to 10 autoclave sterilization cycles and the other as control. Scanning electron microscope was used to observe the changes in surface topography and inner character. For cyclic fatigue resistance, when sterilization was not performed, K3 showed the highest value of TtF means and ProTaper the lowest. The differences between each brand were statistically significant (Pinstruments were intensified greatly after 10 cycles of sterilization. Cycle fatigue resistance is different among instruments of different brands. Autoclave sterilization may increase fatigue resistance of the 3 brands. Autoclave sterilization may increase the surface roughness and inner defects in cross section.

  16. Apical extrusion of debris and irrigants using hand and three rotary instrumentation systems- An in vitro study

    Directory of Open Access Journals (Sweden)

    Koppolu Madhusudhana

    2010-01-01

    Full Text Available Introduction: Sterilization of the root canal is a prime aim of successful endodontics. The cleaning and shaping of the canal is directed as achieving this goal. The extrusion of apical debris has a deleterious effect on the prognosis of root canal treatment. Several instrument designs and instrumentation techniques have been developed to prevent this. Materials and Methods: Forty caries free single rooted human mandibular premolar teeth were divided in four groups of ten teeth each. Teeth in each group were instrumented until the working length with rotary ProTaper, K3, Mtwo systems, and hand K-type stainless steel files. Debris and irrigant extruded from the apical foramen were collected into vials and the amounts were quantitatively determined. The data obtained were analyzed using Kruskal-Wallis one-way analysis of variance and Mann-Whitney U tests. Results: The results show that all instrumentation techniques produced significant amount of extruded debris and irrigant. The engine-driven nickel-titanium systems showed less apical extrusion of debris and irrigant than manual technique. No statistically significant difference was found between the groups at [P > 0.05]. Maximum apical debris and irrigant extrusion was seen with K-file group and least in the Mtwo group. Conclusions: The use of rotary files and techniques to perform instrumentation does show less extrusion of the debris and irrigant from the apex. This can contribute to more successful endodontic therapy.

  17. Apical extrusion of debris and irrigants using hand and three rotary instrumentation systems − An in vitro study.

    Science.gov (United States)

    Madhusudhana, Koppolu; Mathew, Vinod Babu; Reddy, Nelaturi Madhusudhan

    2010-10-01

    Sterilization of the root canal is a prime aim of successful endodontics. The cleaning and shaping of the canal is directed as achieving this goal. The extrusion of apical debris has a deleterious effect on the prognosis of root canal treatment. Several instrument designs and instrumentation techniques have been developed to prevent this. Forty caries free single rooted human mandibular premolar teeth were divided in four groups of ten teeth each. Teeth in each group were instrumented until the working length with rotary ProTaper, K3, Mtwo systems, and hand K-type stainless steel files. Debris and irrigant extruded from the apical foramen were collected into vials and the amounts were quantitatively determined. The data obtained were analyzed using Kruskal-Wallis one-way analysis of variance and Mann-Whitney U tests. The results show that all instrumentation techniques produced significant amount of extruded debris and irrigant. The engine-driven nickel-titanium systems showed less apical extrusion of debris and irrigant than manual technique. No statistically significant difference was found between the groups at [P > 0.05]. Maximum apical debris and irrigant extrusion was seen with K-file group and least in the Mtwo group. The use of rotary files and techniques to perform instrumentation does show less extrusion of the debris and irrigant from the apex. This can contribute to more successful endodontic therapy.

  18. Apical extrusion of debris and irrigants using hand and three rotary instrumentation systems– An in vitro study

    Science.gov (United States)

    Madhusudhana, Koppolu; Mathew, Vinod Babu; Reddy, Nelaturi Madhusudhan

    2010-01-01

    Introduction: Sterilization of the root canal is a prime aim of successful endodontics. The cleaning and shaping of the canal is directed as achieving this goal. The extrusion of apical debris has a deleterious effect on the prognosis of root canal treatment. Several instrument designs and instrumentation techniques have been developed to prevent this. Materials and Methods: Forty caries free single rooted human mandibular premolar teeth were divided in four groups of ten teeth each. Teeth in each group were instrumented until the working length with rotary ProTaper, K3, Mtwo systems, and hand K-type stainless steel files. Debris and irrigant extruded from the apical foramen were collected into vials and the amounts were quantitatively determined. The data obtained were analyzed using Kruskal-Wallis one-way analysis of variance and Mann-Whitney U tests. Results: The results show that all instrumentation techniques produced significant amount of extruded debris and irrigant. The engine-driven nickel-titanium systems showed less apical extrusion of debris and irrigant than manual technique. No statistically significant difference was found between the groups at [P > 0.05]. Maximum apical debris and irrigant extrusion was seen with K-file group and least in the Mtwo group. Conclusions: The use of rotary files and techniques to perform instrumentation does show less extrusion of the debris and irrigant from the apex. This can contribute to more successful endodontic therapy. PMID:22114427

  19. Fatigue resistance of engine-driven rotary nickel-titanium endodontic instruments.

    Science.gov (United States)

    Chaves Craveiro de Melo, Marta; Guiomar de Azevedo Bahia, Maria; Lopes Buono, Vicente Tadeu

    2002-11-01

    A comparative study of the fatigue resistance of engine-driven nickel-titanium endodontic instruments was performed, aiming to access the influence of the cutting flute design and of the size of the files that reach the working length in curved canal shaping. Geometrical conditions similar to those found in practice were used. Series 29 #5 ProFile, together with #6 and #8 Quantec instruments, were tested in artificial canals with a 45-degree angle of curvature and 5-mm radius of curvature. It was observed that the size of the instrument, which determines the maximum strain amplitude during cyclic deformation, is the most important factor controlling fatigue resistance. The effect of heat sterilization on the fatigue resistance of the instruments was also examined. The results obtained indicate that the application of five sterilization procedures in dry heat increases the average number of cycles to failure of unused instruments by approximately 70%.

  20. Metallurgical characterization of controlled memory wire nickel-titanium rotary instruments.

    Science.gov (United States)

    Shen, Ya; Zhou, Hui-Min; Zheng, Yu-Feng; Campbell, Les; Peng, Bin; Haapasalo, Markus

    2011-11-01

    To improve the fracture resistance of nickel-titanium (NiTi) files, manufacturers have introduced new alloys and developed new manufacturing processes for the fabrication of NiTi files. This study aimed to examine the phase transformation behavior and microstructure of NiTi instruments from a novel controlled memory NiTi wire (CM wire). Instruments of EndoSequence (ES), ProFile (PF), ProFile Vortex (Vortex), Twisted Files (TF), Typhoon (TYP), and Typhoon™ CM (TYP CM), all size 25/.04, were examined by differential scanning calorimetry (DSC) and x-ray diffraction (XRD). Microstructures of etched instruments were observed by optical microscopy and scanning electron microscopy with x-ray energy-dispersive spectrometric (EDS) analyses. The DSC analyses showed that each segment of the TYP CM and Vortex instruments had an austenite transformation completion or austenite-finish (A(f)) temperature exceeding 37°C, whereas the NiTi instruments made from conventional superelastic NiTi wire (ES, PF, and TYP) and TF had A(f) temperatures substantially below mouth temperature. The higher A(f) temperature of TYP CM instruments was consistent with a mixture of austenite and martensite structure, which was observed at room temperature with XRD. All NiTi instruments had room temperature martensite microstructures consisting of colonies of lenticular features with substantial twinning. EDS analysis indicated that the precipitates in all NiTi instruments were titanium-rich, with an approximate composition of Ti(2)Ni. The TYP CM and Vortex instruments with heat treatment contribute to increase austenite transformation temperature. The CM instrument has significant changes in the phase transformation behavior, compared with conventional superelastic NiTi instruments. Copyright © 2011 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  1. Apically extruded debris with three contemporary Ni-Ti instrumentation systems: An ex vivo comparative study

    OpenAIRE

    Logani Ajay; Shah Naseem

    2008-01-01

    Aim: To comparatively evaluate the amount of apically extruded debris when ProTaper hand, ProTaper rotary and ProFile systems were used for the instrumentation of root canals. Materials and Methods: Thirty minimally curved, mature, human mandibular premolars with single canals were randomly divided into three groups of ten teeth each. Each group was instrumented using one of the three instrumentation systems: ProTaper hand, ProTaper rotary and ProFile. Five milliliters of sterile water wer...

  2. Shaping ability of NT Engine and McXim rotary nickel-titanium instruments in simulated root canals. Part 2.

    Science.gov (United States)

    Thompson, S A; Dummer, P M

    1997-07-01

    The aim of this laboratory-based study was to determine the shaping ability of NT Engine and McXim nickel-titanium rotary instruments in simulated root canals. A total of 40 canals with four different shapes in terms of angle and position of curve were prepared with NT Engine and McXim instruments, using the technique recommended by the manufacturer. Part 2 of this report describes the efficacy of the instruments in terms of prevalence of canal aberrations, the amount and direction of canal transportation and overall postoperative shape. Pre- and postoperative images of the canals were taken using a video camera attached to a computer with image analysis software. The pre- and postoperative views were superimposed to highlight the amount and position of material removed during preparation. No zips, elbows, perforations or danger zones were created during preparation. Forty-two per cent of canals had ledges on the outer aspect of the curve, the majority of which (16 out of 17) occurred in canals with short acute curves. There were significant differences (P Engine and McXim rotary nickel-titanium instruments created no aberrations other than ledges and produced only minimal transportation. The overall shape of canals was good.

  3. Instrument separation analysis of multi-used ProTaper Universal rotary system during root canal therapy.

    Science.gov (United States)

    Wu, Jintao; Lei, Gang; Yan, Ming; Yu, Yan; Yu, Jinhua; Zhang, Guangdong

    2011-06-01

    The purpose of this study was to identify the influential factors responsible for clinical instrument separation of reused ProTaper Universal rotary instruments (Dentsply Maillefer, Ballaigues, Switzerland). Six thousand one hundred fifty-four root canals in 2,654 teeth were prepared using ProTaper Universal files in endodontic clinics. Separation incidence was determined based on the number of treated teeth or canals. Data were collected including the size of fractured instrument, the length and location of a broken segment within the root canal, and the curvature of canal. The chi-square test and independent samples t test were used to determine the statistical significance. The overall instrument separation incidences were 2.6% according to the number of teeth and 1.1% according to the canal number, respectively. Separation incidences according to the number of teeth or canals were significantly higher (P molars than those in premolars or anterior teeth. Because of its largest diameter, F3 file presented the highest separation incidence according to the number of teeth (1.0%) or canals (0.4%); 47.5% instrument separation of mandibular molars and 61.5% instrument separation of maxillary molars happened in the mesiobuccal canals. Moreover, 91.4% fragments were located in the apical third of root canals, and 54.2% instrument separation occurred in severely curved canals. There was a significant difference (P < .05) in the mean fracture length between shaping (2.42 ± 0.73 mm) and finishing files (3.32 ± 0.73 mm). Separation incidence according to the canal number is more reliable than that according to the number of teeth because of the variable canal number in different teeth. The tooth type, rotary file size, canal location, and anatomy were correlated with the instrument separation of reused ProTaper Universal files. Copyright © 2011 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  4. Cutting efficiency of nickel-titanium rotary and reciprocating instruments after prolonged use.

    Science.gov (United States)

    Gambarini, Gianluca; Giansiracusa Rubini, Alessio; Sannino, Giampaolo; Di Giorgio, Gianni; Di Giorgio, Fabrizio; Piasecki, Lucila; Al-Sudani, Dina; Plotino, Gianluca; Testarelli, Luca

    2016-01-01

    The aim of the present study was to compare the cutting efficiency of Twisted File instruments used in continuous rotation or TF Adaptive motion and evaluate if prolonged use significantly affected their cutting ability. 20 new NiTi instruments were used in the present study (TF tip size 35, 0.06 taper; Sybron-Endo, Orange, CA, USA), divided into 2 subgroups of 10 instruments each, depending on which movement was selected on the endodontic motor. Group 1: TF instruments were activated using the program TF continuous rotation at 500 rpm and torque set at 2 N; Group 2: TF instruments were activated using the reciprocating TF Adaptive motion. Cutting efficiency was tested in a device developed to test the cutting ability of endodontic instruments. Each instrument cut 10 plastic blocks (10 uses) and the length of the surface cut in a plastic block after 1 min was measured in a computerized program with a precision of 0.1 mm. Maximum penetration depth was calculated after 1 use and after 10 uses, and mean and standard deviation (SD) of each group was calculated. Data were statistically analyzed with a one-way ANOVA test (P cut a mean depth of 10.4 mm (SD = 0.6 mm) after the first use and 10.1 mm (SD 1.1 mm) after 10 uses, while TF instruments used with the Adaptive motion cut a mean depth of 9.9 mm (SD = 0.7 mm) after the first use and 9.6 mm (SD = 0.9 mm) after 10 uses. There was no statistically significant difference between the two groups investigated (P > 0.05) nor between instruments after 1 or 10 uses. In conclusion, the TFA motion showed a lateral cutting ability similar to continuous rotation and all tested instruments exhibited the same cutting ability after prolonged use.

  5. Influence of Surface Roughness on the Fatigue Life of Nickel-Titanium Rotary Endodontic Instruments.

    Science.gov (United States)

    Lopes, Hélio P; Elias, Carlos N; Vieira, Márcia V B; Vieira, Victor T L; de Souza, Letícia Chaves; Dos Santos, Alexander Lopes

    2016-06-01

    The goal of the present study was to evaluate the influence of surface grooves (peaks and valleys) resulting from machining during the manufacturing process of polished and unpolished nickel-titanium BR4C endodontic files on the fatigue life of the instruments. Ten electropolished and 10 unpolished endodontic files were provided by the manufacturer. Specimens were from the same batch, but the unpolished instruments were removed from the production line before surface treatment. The instruments were evaluated with a profilometer to quantify the surface roughness on the working part of the instruments. Then the files were subjected to rotating bending fatigue tests. Analysis with the profilometer showed that surface grooves were deeper on the unpolished instruments compared with their electropolished counterparts. In the rotating bending fatigue test, the mean and standard deviation for the number of cycles until fracture (NCF) were greater for instruments with less pronounced grooves. Student t test revealed significant differences in all tests (P instruments tested; the smaller the groove depth, the greater the NCF. Copyright © 2016 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  6. Defect propagation in NiTi rotary instruments: a noncontact optical profilometry analysis.

    Science.gov (United States)

    Barbosa, I; Ferreira, F; Scelza, P; Neff, J; Russano, D; Montagnana, M; Zaccaro Scelza, M

    2018-04-10

    To evaluate the presence and propagation of defects and their effects on surfaces of nickel-titanium (NiTi) instruments using noncontact, three-dimensional optical profilometry, and to assess the accuracy of this method of investigation. The flute surface areas of instruments from two commercial instrumentation systems, namely Reciproc R25 (n = 5) and WaveOne Primary (n = 5), were assessed and compared before and after performing two instrumentation cycles in simulated root canals in clear resin blocks. All the analyses were conducted on areas measuring 211 × 211 μm, located 3 mm from the tips of the instruments. A quantitative analysis was conducted before and after the first and second instrumentation cycles, using the Sa (average roughness over the measurement field), Sq (root mean square roughness) and Sz (average height over the measurement field) amplitude parameters. All the data were submitted to statistical analysis at a 5% level of significance. There was a significant increase (P = 0.007) in wear in both groups, especially between baseline and the second instrumentation cycle, with significantly higher wear values being observed on WaveOne instruments (Sz median values = 33.68 and 2.89 μm, respectively, for WO and RP groups). A significant increase in surface roughness (P = 0.016 and P = 0.008, respectively, for Sa and Sq) was observed in both groups from the first to the second instrumentation cycle, mostly in WaveOne specimens. Qualitative analysis revealed a greater number of defects on the flute topography of all the instruments after use. More defects were identified in WaveOne Primary instruments compared to Reciproc R25, irrespective of the evaluation stage. The investigation method provided an accurate, repeatable and reproducible assessment of NiTi instruments at different time-points. © 2018 International Endodontic Journal. Published by John Wiley & Sons Ltd.

  7. Rotary Transformer

    Science.gov (United States)

    McLyman, Colonel Wm. T.

    1996-01-01

    None given. From first Par: Many spacecraft (S/C) and surface rovers require the transfer of signals and power across rotating interfaces. Science instruments, antennas and solar arrays are elements needing rotary power transfer for certain (S/C) configurations. Delivery of signal and power has mainly been done by using the simplest means, the slip ring approach. This approach, although simple, leaves debris generating noise over a period of time...The rotary transformer is a good alternative to slip rings for signal and power transfer.

  8. Preservation of root canal anatomy using self-adjusting file instrumentation with glide path prepared by 20/0.02 hand files versus 20/0.04 rotary files

    Science.gov (United States)

    Jain, Niharika; Pawar, Ajinkya M.; Ukey, Piyush D.; Jain, Prashant K.; Thakur, Bhagyashree; Gupta, Abhishek

    2017-01-01

    Objectives: To compare the relative axis modification and canal concentricity after glide path preparation with 20/0.02 hand K-file (NITIFLEX®) and 20/0.04 rotary file (HyFlex™ CM) with subsequent instrumentation with 1.5 mm self-adjusting file (SAF). Materials and Methods: One hundred and twenty ISO 15, 0.02 taper, Endo Training Blocks (Dentsply Maillefer, Ballaigues, Switzerland) were acquired and randomly divided into following two groups (n = 60): group 1, establishing glide path till 20/0.02 hand K-file (NITIFLEX®) followed by instrumentation with 1.5 mm SAF; and Group 2, establishing glide path till 20/0.04 rotary file (HyFlex™ CM) followed by instrumentation with 1.5 mm SAF. Pre- and post-instrumentation digital images were processed with MATLAB R 2013 software to identify the central axis, and then superimposed using digital imaging software (Picasa 3.0 software, Google Inc., California, USA) taking five landmarks as reference points. Student's t-test for pairwise comparisons was applied with the level of significance set at 0.05. Results: Training blocks instrumented with 20/0.04 rotary file and SAF were associated less deviation in canal axis (at all the five marked points), representing better canal concentricity compared to those, in which glide path was established by 20/0.02 hand K-files followed by SAF instrumentation. Conclusion: Canal geometry is better maintained after SAF instrumentation with a prior glide path established with 20/0.04 rotary file. PMID:28855752

  9. Comparison of the Effect of Canal Preparation by Step Back Technique Using Hand Instruments and Gates Glidden Drills with ProTaper Universal Rotary System on the Root Resistance to Vertical Fracture

    Directory of Open Access Journals (Sweden)

    A Abbaszadegan

    2013-06-01

    Full Text Available Introduction: Cleaning and shaping of the root canal system with an efficient and safe technique are the major goals of root canal treatment. The aim of this study was to compare the conventional root canal preparation technique by hand instruments and Gates Glidden drills with ProTaper Universal Rotary system on the root susceptibility to vertical fracture. Methods: Thirty extracted human mandibular premolars were randomly assigned to two groups. In group I, apical preparation was performed with k-files up to #40 utilizing step back technique and coronal flaring was done with Gates Glidden drills. In group II, ProTaper Universal Rotary instruments were used up to the file F4. All teeth were obturated with lateral compaction technique using gutta-percha and AH26 sealer. A simulated periodontal ligament was fabricated, and the teeth were mounted. A stainless steel finger spreader #35 was mounted in an Instron testing machine and the necessary load to cause a root fracture was inserted and recorded. The obtained data were analyzed statistically using T-test. Results: The force required to fracture was significantly lower for the roots prepared by ProTaper instruments in comparison with the specimens prepared by hand instruments and Gates Glidden drills (P< 0.001. Conclusion: Canal preparation with ProTaper rotary instruments can make the roots more susceptible to vertical fracture than traditional instrumentation with k-files and Gates Glidden drills.

  10. Hand-operated and rotary ProTaper instruments: a comparison of working time and number of rotations in simulated root canals.

    Science.gov (United States)

    Pasqualini, Damiano; Scotti, Nicola; Tamagnone, Lorenzo; Ellena, Federica; Berutti, Elio

    2008-03-01

    The aim of this study was to compare the effective shaping time and number of rotations required by an endodontist working with hand and rotary ProTaper instruments to completely shape simulated root canals. Eighty Endo Training Blocks (curved canal shape) were used. Manual preflaring was performed with K-Flexofiles #08-10-12-15-17 and #20 Nitiflex at a working length of 18 mm. Specimens were then randomly assigned to 2 different groups (n = 40); group 1 was shaped by using hand ProTaper and group 2 with ProTaper rotary. The number of rotations made in the canal and the effective time required to achieve complete canal shaping were recorded for each instrument. Differences between groups were analyzed with the nonparametric Mann-Whitney U test (P Hand ProTaper required significantly fewer rotations (P ProTaper, whereas the effective working time to fully shape the simulated canal was significantly higher (P hand ProTaper.

  11. Evaluation of Root Canal Preparation Using Rotary System and Hand Instruments Assessed by Micro-Computed Tomography.

    Science.gov (United States)

    Stavileci, Miranda; Hoxha, Veton; Görduysus, Ömer; Tatar, Ilkan; Laperre, Kjell; Hostens, Jeroen; Küçükkaya, Selen; Muhaxheri, Edmond

    2015-06-20

    Complete mechanical preparation of the root canal system is rarely achieved. Therefore, the purpose of this study was to evaluate and compare the root canal shaping efficacy of ProTaper rotary files and standard stainless steel K-files using micro-computed tomography. Sixty extracted upper second premolars were selected and divided into 2 groups of 30 teeth each. Before preparation, all samples were scanned by micro-computed tomography. Thirty teeth were prepared with the ProTaper system and the other 30 with stainless steel files. After preparation, the untouched surface and root canal straightening were evaluated with micro-computed tomography. The percentage of untouched root canal surface was calculated in the coronal, middle, and apical parts of the canal. We also calculated straightening of the canal after root canal preparation. Results from the 2 groups were statistically compared using the Minitab statistical package. ProTaper rotary files left less untouched root canal surface compared with manual preparation in coronal, middle, and apical sector (p<0.001). Similarly, there was a statistically significant difference in root canal straightening after preparation between the techniques (p<0.001). Neither manual nor rotary techniques completely prepared the root canal, and both techniques caused slight straightening of the root canal.

  12. In vitro investigation of the cleaning efficacy, shaping ability, preparation time and file deformation of continuous rotary, reciprocating rotary and manual instrumentations in primary molars

    Directory of Open Access Journals (Sweden)

    Nahid Ramazani

    2016-03-01

    Full Text Available Background. Efficient canal preparation is the key to successful root canal treatment. This study aimed to assess the cleaning and shaping ability, preparation time and file deformation of rotary, reciprocating and manual instrumentation in canal preparation of primary molars. Methods. The mesiobuccal canals of 64 extracted primary mandibular second molars were injected with India ink. The samples were randomly divided into one control and three experimental groups. Experimental groups were instrumented with K-file, Mtwo in continuous rotation and Reciproc in reciprocating motion, respectively. The control group received no treatment. The files were discarded after four applications. Shaping ability was evaluated using CBCT. After clearing, ink removal was scored. Preparation time and file fracture or deformation was also recorded. Data were analyzed with SPSS 19 using chi-squared, Fisher’s exact test, Kruskal-Wallis and post hoc tests at a significance level of 0.05. Results. Considering cleanliness, at coronal third Reciproc was better than K-file (P < 0.001, but not more effective than Mtwo (P = 0.080. Furthermore, Mtwo leaved the canal cleaner than K-file (P = 0.001. In the middle third, only Reciproc exhibited better cleaning efficacy than K-file (P = 0.005. In the apical third, no difference was detected between the groups (P = 0.794. Regarding shaping ability, no differences were found between Reciproc and Mtwo (P = 1.00. Meanwhile, both displayed better shaping efficacy than K-file (P < 0.05. Between each two groups, there were differences in preparation time (P < 0.05, with Reciproc being the fastest. No file failure occurred. Conclusion. Fast and sufficient cleaning and shaping could be achieved with Mtwo and especially with Reciproc.

  13. In vitro investigation of the cleaning efficacy, shaping ability, preparation time and file deformation of continuous rotary, reciprocating rotary and manual instrumentations in primary molars.

    Science.gov (United States)

    Ramazani, Nahid; Mohammadi, Abbas; Amirabadi, Foroogh; Ramazani, Mohsen; Ehsani, Farzane

    2016-01-01

    Background. Efficient canal preparation is the key to successful root canal treatment. This study aimed to assess the cleaning and shaping ability, preparation time and file deformation of rotary, reciprocating and manual instrumentation in canal preparation of primary molars. Methods. The mesiobuccal canals of 64 extracted primary mandibular second molars were injected with India ink. The samples were randomly divided into one control and three experimental groups. Experimental groups were instrumented with K-file, Mtwo in continuous rotation and Reciproc in reciprocating motion, respectively. The control group received no treatment. The files were discarded after four applications. Shaping ability was evaluated using CBCT. After clearing, ink removal was scored. Preparation time and file fracture or deformation was also recorded. Data were analyzed with SPSS 19 using chi-squared, Fisher's exact test, Kruskal-Wallis and post hoc tests at a significance level of 0.05. Results. Considering cleanliness, at coronal third Reciproc was better than K-file (P < 0.001), but not more effective than Mtwo (P = 0.080). Furthermore, Mtwo leaved the canal cleaner than K-file (P = 0.001). In the middle third, only Reciproc exhibited better cleaning efficacy than K-file (P = 0.005). In the apical third, no difference was detected between the groups (P = 0.794). Regarding shaping ability, no differences were found between Reciproc and Mtwo (P = 1.00). Meanwhile, both displayed better shaping efficacy than K-file (P < 0.05). Between each two groups, there were differences in preparation time (P < 0.05), with Reciproc being the fastest. No file failure occurred. Conclusion. Fast and sufficient cleaning and shaping could be achieved with Mtwo and especially with Reciproc.

  14. Influence of Rotary Instrumentation with Continuous Irrigation on Pain and Neuropeptide Release Levels: A Randomized Clinical Trial.

    Science.gov (United States)

    Bıçakcı, Hazal; Çapar, İsmail Davut; Genç, Selin; İhtiyar, Alperen; Sütçü, Recep

    2016-11-01

    The first objective was to determine correlation among various experimental and clinical pain measurement procedures. The second objective was to evaluate the influence of rotary instrumentation with continuous irrigation on pain and neuropeptide release levels. Forty patients who had preoperative pain at the levels of 3-8 on the visual analogue scale were included. Gingival crevicular fluid (GCF) samples were collected. Patients were randomly assigned to 2 treatment groups, the standard preparation group and the preparation with continuous irrigation group. Apical fluid samples (AFS) were collected after instrumentation. In the second visit, the patients' pain levels were recorded, and GCF and AFS were obtained. Substance P, calcitonin-gene related peptide (CGRP), interleukin (IL)-1β, and IL-10 levels were analyzed from the GCF and AFS samples. For comparison between groups, the Mann-Whitney test was used (P Rotary preparation with continuous irrigation has not been more effective than the standard preparation method for reducing pain. Because of determination of the correlation between CGRP and IL-10 with percussion pain, these neuropeptides can be used in further studies. Crown Copyright © 2016. Published by Elsevier Inc. All rights reserved.

  15. In vitro resistance to fracture of two nickel-titanium rotary instruments made with different thermal treatments.

    Science.gov (United States)

    Miccoli, Gabriele; Gaimari, Gianfranco; Seracchiani, Marco; Morese, Antonio; Khrenova, Tatyana; Di Nardo, Dario

    2017-01-01

    Aim of the study was to evaluate effectiveness of different heat treatments in improving Ni-Ti endodontic rotary instruments' resistance to fracture. 24 new NiTi instruments similar in length and shape: 12 M3 instruments, tip size 25 and .06 taper (United Dental, Shanghai, China), and 12 M3 Pro Gold instruments tip size 25 and .06 taper (United Dental, Shanghai, China), were tested in a 60° curved artificial root canal. Each group received a different heat treatment. Cycles to fracture were calculated for each instrument. Differences among groups were evaluated with an analysis of variance test (significance level was set at Pinstruments were significantly more resistant to fatigue (mean values = 1012, SD +/- 77) than M3 instruments (mean values = 748, SD +/- 62). No statistically significant differences were found between fragments' lengths (p>0,05). An increased flexibility and the reduction of internal defects produced by heat treatments during or after manufacturing processes, may be responsible for improving resistance to cyclic fatigue and flexural stresses.

  16. Comparison of the Effect of Canal Preparation by Step Back Technique Using Hand Instruments and Gates Glidden Drills with ProTaper Universal Rotary System on the Root Resistance to Vertical Fracture

    OpenAIRE

    A Abbaszadegan; Z Sadat Aleyasin; M Sedigh Shamsi; Sh Shahriari

    2013-01-01

    Introduction: Cleaning and shaping of the root canal system with an efficient and safe technique are the major goals of root canal treatment. The aim of this study was to compare the conventional root canal preparation technique by hand instruments and Gates Glidden drills with ProTaper Universal Rotary system on the root susceptibility to vertical fracture. Methods: Thirty extracted human mandibular premolars were randomly assigned to two groups. In group I, apical preparation was performed ...

  17. Comparison of cyclic fatigue resistance of novel nickel-titanium rotary instruments.

    Science.gov (United States)

    Capar, Ismail Davut; Ertas, Huseyin; Arslan, Hakan

    2015-04-01

    New files (ProTaper Next/HyFlex/OneShape) are made from novel nickel-titanium (NiTi) alloys/treatments. The purpose of this study was to compare the cyclic fatigue resistance of these new instruments with that of Revo-S instruments. Four groups of 20 NiTi endodontic instruments were tested in steel canals with a 3 mm radius and a 60° angle of curvature. The cyclic fatigue of the following NiTi instruments with a tip size 25 and 0.06 taper that were manufactured with different alloys was tested: ProTaper Next X2 (M-Wire), OneShape (conventional NiTi), Revo-S Shaping Universal (conventional NiTi) and HyFlex 25/0.6 (controlled memory NiTi wire). A one-way anova and post-hoc Tukey's test (α = 0.05) revealed that the HyFlex files had the highest fatigue resistance and the Revo-S had the least fatigue resistance among the groups (P < 0.001). © 2014 Australian Society of Endodontology.

  18. Comparative evaluation of effect of rotary and reciprocating single-file systems on pericervical dentin: A cone-beam computed tomography study.

    Science.gov (United States)

    Zinge, Priyanka Ramdas; Patil, Jayaprakash

    2017-01-01

    The aim of this study is to evaluate and compare the effect of one shape, Neolix rotary single-file systems and WaveOne, Reciproc reciprocating single-file systems on pericervical dentin (PCD) using cone-beam computed tomography (CBCT). A total of 40 freshly extracted mandibular premolars were collected and divided into two groups, namely, Group A - Rotary: A 1 - Neolix and A 2 - OneShape and Group B - Reciprocating: B 1 - WaveOne and B 2 - Reciproc. Preoperative scans of each were taken followed by conventional access cavity preparation and working length determination with 10-k file. Instrumentation of the canal was done according to the respective file system, and postinstrumentation CBCT scans of teeth were obtained. 90 μm thick slices were obtained 4 mm apical and coronal to the cementoenamel junction. The PCD thickness was calculated as the shortest distance from the canal outline to the closest adjacent root surface, which was measured in four surfaces, i.e., facial, lingual, mesial, and distal for all the groups in the two obtained scans. There was no significant difference found between rotary single-file systems and reciprocating single-file systems in their effect on PCD, but in Group B 2 , there was most significant loss of tooth structure in the mesial, lingual, and distal surface ( P file system removes more PCD as compared to other experimental groups, whereas Neolix single file system had the least effect on PCD.

  19. Application of non-destructive impedance-based monitoring technique for cyclic fatigue evaluation of endodontic nickel-titanium rotary instruments.

    Science.gov (United States)

    Chang, Yau-Zen; Liu, Mou-Chuan; Pai, Che-An; Lin, Chun-Li; Yen, Kuang-I

    2011-06-01

    This study investigates the application of non-destructive testing based on the impedance theory in the cyclic fatigue evaluation of endodontic Ni-Ti rotary instruments. Fifty Ni-Ti ProTaper instruments were divided into five groups (n=10 in Groups A to E). Groups A to D were subjected to cyclic fatigue within an artificial canal (Group E was the control group). The mean value of the total life limit (TLL), defined as the instrument being rotated until fracture occurred was found to be 104 s in Group A. Each rotary instrument in Groups B, C and D were rotated until the tested instruments reached 80% (84 s), 60% (62 s) and 40% (42 s) of the TLL. After fatigue testing, each rotary instrument was mounted onto a custom-developed non-destructive testing device to give the tip of the instrument a progressive sideways bend in four mutually perpendicular directions to measure the corresponding impedance value (including the resistance and the reactance). The results indicated that the impedance value showed the same trend as the resistance, implying that the impedance was primarily affected by the resistance. The impedance value for the instruments in the 80% and 60% TLL groups increased by about 6 mΩ (about 7.5%) more than that of the instruments in the intact and 40% TLL groups. The SEM analysis result showed that crack striations were only found at the tip of the thread on the cracked surface of the instrument, consistent with the impedance measurements that found the impedance value of the cracked surface to be significantly different from those in other surfaces. These findings indicate that the impedance value may represent an effective parameter for evaluating the micro-structural status of Ni-Ti rotary instruments subjected to fatigue loading. Copyright © 2010 IPEM. Published by Elsevier Ltd. All rights reserved.

  20. Fatigue testing of controlled memory wire nickel-titanium rotary instruments.

    Science.gov (United States)

    Shen, Ya; Qian, Wei; Abtin, Houman; Gao, Yuan; Haapasalo, Markus

    2011-07-01

    To improve the fracture resistance of nickel-titanium (NiTi) files, manufacturers have introduced new alloys to manufacture NiTi files and developed new manufacturing processes. This study was aimed to examine the fatigue behavior of NiTi instruments from a novel controlled memory NiTi wire (CM Wire). Instruments of ProFile, Typhoon (TYP), Typhoon CM (TYP CM), DS-SS0250425NEYY (NEYY), and DS-SS0250425NEYY CM (NEYY CM) (DS Dental, Johnson City, TN) all size 25/.04 were subjected to rotational bending at the curvature of 35° and 45° in air at the temperature of 23° ± 2°C, and the number of revolutions to fracture (N(f)) was recorded. The fracture surface of all fragments was examined by a scanning electron microscope. The crack-initiation sites, the percentage of dimple area to the whole fracture cross-section, and the surface strain amplitude (ε(a)) were noted. The new alloy yielded an improvement of over three to eight times in N(f) of CM files than that of conventional NiTi files (P wire (58%-100%) had one crack origin. The values of the fraction area occupied by the dimple region were significantly smaller on CM NiTi instruments compared with conventional NiTi instruments (P wire at both curvatures (P Wire had a significantly higher N(f) and lower surface strain amplitude than the conventional NiTi wire files with identical design. Copyright © 2011 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  1. The effect of different temperature and concentration of sodium hypochlorite on the elimination of E.Faecalis using rotary instrumentation and intermittent passive ultrasonic irrigation

    International Nuclear Information System (INIS)

    AlMadi, Ebtissam M

    2008-01-01

    The purpose of this study was to compare the intracanal bacterial reduction using rotary instrumentation and intermittent passive ultrasonic irrigation (IPUI) with different concentrations and temperatures of NaOCl in different canal tapers. The root canals of seventy-two extracted single-rooted teeth were instrumented up to size 20k file and inoculated with E. faecalis. The teeth were divided into 5 experimental groups and one control. The root canals in the control group were shaped to a 0.04 taper using ProFile rotary files, with 1.5 minute of IPUI by NaOCl at a concentration of 2.5% and room temperature of 25degreeC for 30 seconds at a time at three intervals. In Group 1, the canals were shaped to a 0.06 taper, and in Groups 2 and 3 - the temperature of NaOCl used was 37degreeC and 45degreeC respectively, and in Groups 4 and 5 - the concentrations of NaOCl were 1% and 5% respectively. The canals were incubated at 37 degree C for 48 hours and bacterial samples were obtained using paper points and plated on agar plates. The zones of bacterial growth were measured and statistical analysis was performed. There was significantly more bacterial growth in the control group than in Groups 1, 2, 3 and 5. Furthermore, there was a significant reduction in bacterial growth in Group V compared to Group 4. The result of this study showed that significant bacterial reduction in contaminated root canals could be obtained using intermittent passive ultrasonic irrigation combined with 2.5% NaOCl at 37degreeC in canals prepared to a taper of 0.06. In addition, complete bacterial eradication could be obtained using IPUI with 2.5% NaOCl at 45degreeC or 5% NaOCl at room temperature (37degreeC). (author)

  2. Quantitative evaluation of apical extrusion of debris and irrigants using four rotary instrumentation systems: an in vitro study.

    Science.gov (United States)

    Nagaveni, S Aspalli; Balakoti, K Reddy; Smita, Karan; Ratnakar, P; Satish, S V; Aravind, T

    2013-11-01

    The apical extrusion of infected debris may have the potential to disrupt the balance between microbial aggression and host defense, resulting in incidents of acute inflammation. During preparation, irrigants and debris, such as bacteria, dentin filings and necrotic tissue may be extruded into the periradicular region leading to periapical inflammation and postoperative flare ups. Using an instrumentation technique that minimizes apical extrusion would be beneficial to both the practitioner and patient. The purpose of the study was to evaluate the weight of debris and volume of irrigant extruded apically from extracted teeth in vitro after endodontic instrumentation using four different rotary root canal instrumentation systems. Four groups of each 20 extracted mandibular premolars were instrumented using one of the four systems: ProTaper Universal (Dentsply Maillefer, Ballaigues, Switzerland)), Hero-shaper (MicroMega, Besancon, France), RaCe (FKG Dentaire, La-Chaux-de-Fonds, Switzerland) and K3 (SybronEndo, West Collins, CA). Debris and irrigant extruded from the apical foramen during instrumentation were collected in preweighed test tubes. Volume of irrigant extruded was noted. The containers were stored in incubator at 70° for two days to evaporate the moisture. Weight of dry debris was noted. Data was analyzed using Kruskall-Wallis and Mann-Whitney U test at a significance of 0.001. The results indicated that all of the instrumentation systems tested caused measurable apical extrusion of debris and irrigants. Higher extrusion was observed with Protaper system which was statistically significant with Hero-Shaper, RaCe and K3 systems. There were no statistical differences between Hero-shaper, K3 and RaCe systems (p < 0.05). All instrumentation techniques apically extruded debris and irrigant. However, Hero-shaper, K3 and RaCe systems produced less extruded debris and irrigant than the Protaper system.

  3. Comparative study of root-canal shaping with stainless steel and rotary NiTi files performed by preclinical dental students.

    Science.gov (United States)

    Alrahabi, Mothanna

    2015-01-01

    We evaluated the use of NiTi rotary and stainless steel endodontic instruments for canal shaping by undergraduate students. We also assessed the quality of root canal preparation as well as the occurrence of iatrogenic events during instrumentation. In total, 30 third-year dental students attending Taibah University Dental College prepared 180 simulated canals in resin blocks with NiTi rotary instruments and stainless steel hand files. Superimposed images were prepared to measure the removal of material at different levels from apical termination using the GSA image analysis software. Preparation time, procedural accidents, and canal shape after preparation were analyzed using χ 2 and t-tests. The statistical significance level was set at P instruments and stainless steel files; the former was associated with shorter preparation time, less ledge formation (1.1% vs. 14.4%), and greater instrument fracture (5.56% vs. 1.1%). These results indicate that NiTi rotary instruments result in better canal geometry and cause less canal transportation. Manual instrumentation using stainless steel files is safer than rotary instrumentation for inexperienced students. Intensive preclinical training is a prerequisite for using NiTi rotary instruments. These results prompted us to reconsider theoretical and practical coursework when teaching endodontics.

  4. Evaluation of Root Canal Preparation Using Rotary System and Hand Instruments Assessed by Micro-Computed Tomography

    Science.gov (United States)

    Stavileci, Miranda; Hoxha, Veton; Görduysus, Ömer; Tatar, Ilkan; Laperre, Kjell; Hostens, Jeroen; Küçükkaya, Selen; Muhaxheri, Edmond

    2015-01-01

    Background Complete mechanical preparation of the root canal system is rarely achieved. Therefore, the purpose of this study was to evaluate and compare the root canal shaping efficacy of ProTaper rotary files and standard stainless steel K-files using micro-computed tomography. Material/Methods Sixty extracted upper second premolars were selected and divided into 2 groups of 30 teeth each. Before preparation, all samples were scanned by micro-computed tomography. Thirty teeth were prepared with the ProTaper system and the other 30 with stainless steel files. After preparation, the untouched surface and root canal straightening were evaluated with micro-computed tomography. The percentage of untouched root canal surface was calculated in the coronal, middle, and apical parts of the canal. We also calculated straightening of the canal after root canal preparation. Results from the 2 groups were statistically compared using the Minitab statistical package. Results ProTaper rotary files left less untouched root canal surface compared with manual preparation in coronal, middle, and apical sector (protary techniques completely prepared the root canal, and both techniques caused slight straightening of the root canal. PMID:26092929

  5. Analysis of mechanical preparations in extracted teeth using ProTaper rotary instruments: value of the safety quotient.

    Science.gov (United States)

    Blum, J Y; Machtou, P; Ruddle, C; Micallef, J P

    2003-09-01

    The purpose of this study was to apply the Endographe to analyze the vertical forces and torque developed during mechanical preparations in extracted teeth. The data collected in this study may be used to calculate the safety quotient (SQ) as proposed by J.T. McSpadden. The SQ formula is defined as the torque required to break a file at D3 divided by the mean working torque required to cut dentin. The Endographe is a unique force-analyzer device equipped to measure, record, and generate graphs of the vertical forces and torque exerted during root canal preparation. All preparations were performed by endodontists in roots with narrow, more restrictive canals, larger, more open canals, or in roots sectioned in two halves. All canals, including the sectioned canals, were prepared with ProTaper files in accordance with the manufacturer's guidelines for use. For narrow canals, the mean values of the generated vertical forces (g) and torque (g.cm) varied from 80 (+/- 20) g (SX) to 232 (+/- 60) g (F2) and from 80 (+/- 24) g x cm (F1) to 150 (+/- 45) g x cm (S2), respectively. For large canals, the mean values of the generated vertical forces (g) and torque (g x cm) varied from 80 (+/- 20) g (SX) to 340 (+/- 20) g (F1) and from 31 (+/- 9) g x cm (S2) to 96 (+/- 35) g x cm (SX), respectively. The SQ varied from 0.93 to 7.95 for narrow canals and from 1.58 to 14.50 for large canals. The SQ is intended to provide values that can be analyzed to predict whether a rotary file will have a tendency to break or will work safely during clinical use. However, if the formula is going to provide useful information, it must index the "rotation to failure torque" with the "mean working torque" at a specific location along the cutting blades of a file. Additionally, this mathematical formula does not account for factors such as the concentration of forces, the way the instruments are used, or the wear of the instruments. A precise protocol for canal preparation should emphasize using

  6. [Glide path management of rotary nickel-titanium instruments in simulated root canals].

    Science.gov (United States)

    Han, Y; Bai, Y H; Hou, X M

    2018-02-18

    To compare the shaping ability of ProGlider, HyFlex EDM Glidepath File and RaCe ISO 10 with that of PathFile and stainless steel K-file hand instruments in simulated root canals. A total of 60 simulated resin blocks were divided randomly into five groups (n=12), each group prepared with each instrument, respectively. Preparation time was recorded. Pre- and post-operative images were obtained using a scanner and superimposed using Photoshop. The material removal from the inner and outer canal walls beginning from 0 mm at the end point of the canal were measured using ImageJ. Centering ability was determined, accordingly. The data were analyzed using the One-Way ANOVA at a significance level of P0.05). The removal of resin from the outer wall at the apical portion was significantly lower for HyFlex EDM Glidepath File than for ProGlider (PEDM Glidepath File the second most, and the other 3 groups among the same levels. As far as the centering ability was concerned, at the apical portion, HyFlex EDM Glidepath File was the best, ProGlider the second best, no significant difference identified among the other 3 groups. At the curvature portion, ProGlider and HyFlex EDM Glidepath File were the best, PathFile the second, RaCe ISO 10 the third, the worst was the SS K-file. At the straight portion, the difference amongt the 5 groups was not significant. The shaping abilities of ProGlider, HyFlex EDM Glidepath File and RaCe ISO 10 were better or comparable to that of PathFile, while the preparation time for ProGlider reduced significantly, and HyFlex EDM Glidepath File and RaCe ISO 10 removed significantly more resin at the straight portion of the canal.

  7. The relationship between diameter and taper of nickel-titanium rotary instruments on the torsional resistance to fracture

    Directory of Open Access Journals (Sweden)

    Erick Miranda Souza

    Full Text Available Objective: To evaluate the resistance to fracture of rotary Ni-Ti files of various diameters and tapers after torsional stress simulation. Methods: Profile (Dentsply Maillerfer, Ballaigues, Suíça instruments sizes 15 to 40, taper 0.04 and 0.06 were used. Ten instruments of each size and taper were tested, totaling 120 files. The maximum torque (Tmax until fracture was determined in accordance with the ANSI / ADA Protocol Nº 28 . The maximum force was converted into maximum torque using the formula: Tmax = Loadmax x RadiusResults: The diameter (p<0.001 and taper (p<0.001 influenced the maximum torque to fracture. With the increase in diameter and taperthere was a gradual increase in the maximum torque. Using the multiple regression method an equation relating the maximum torque to the diameter (D and the taper (T was found: Tmax = -1.4 + 0.08D + 10.5T. Conclusion: The increase in diameter and taper promoted an increase in resistance to torsion. The variation of the taper from 0.04 to 0.06 in instruments with the same diameter increased resistance to fracture by torsion by around 25%.

  8. Performance of engine-driven rotary endodontic instruments with a superimposed bending deflection: V. Gates Glidden and Peeso drills.

    Science.gov (United States)

    Brantley, W A; Luebke, N H; Luebke, F L; Mitchell, J C

    1994-05-01

    A laboratory study was performed on Gates Glidden and Peeso drills to determine the incidence of shaft fracture when a bending deflection was superimposed on the rotating drills. Samples of sizes #1 to #6 stainless steel Gates Glidden drills, sizes #1 to #6 stainless steel and carbon steel-type P Peeso drills, and sizes #009 to #023 carbon steel-type B-1 Peeso drills from each of two manufacturers were evaluated with a unique apparatus that applied a 2-mm bending deflection while rotating the instruments. The apparatus did not restrict movement of the bur head during rotation. The test drills were rotated at 2500, 4000, and 7000 revolutions per minute, and the number of revolutions at failure was recorded. Scanning electron microscopic observations established that the stainless steel Gates Glidden and Peeso drills failed by ductile fracture, whereas the carbon steel Peeso drills failed by brittle fracture. Instrument fracture was always near the handpiece shank with this test, and the length of the fractured drills was measured from the working tip. It is recommended that this additional test be adopted to determine fatigue properties of engine-driven rotary endodontic instruments in establishing international performance standards.

  9. The efficacy of two rotary NiTi instruments and H-files to remove gutta-percha from root canals

    Science.gov (United States)

    Akpınar, Kerem E.; Altunbaş, Demet

    2012-01-01

    Objective: The aim of this study was to evaluate the efficacy of R-Endo® and K3® rotary nickel-titanium instruments compared with manual instrumentation with H-files, with use of a solvent, for removal of gutta-percha during retreatment. Study design: Forty five freshly extracted human single-rooted teeth, each with one root canal, were instrumented with K-files and filled using cold lateral compaction of gutta-percha and AH 26® sealer. The teeth were randomly divided into three groups of 15 specimens each. Removal of gutta-percha was performed with the following devices and techniques: Group 1 (H-files), Group 2 (R-Endo®), and Group 3 (K3®). The specimens were rendered transparent for the evaluation of the area of remaining gutta-percha/sealer in buccolingual and mesiodistal directions. Statistical analysis as performed by using one-way ANOVA and Kruskal-Wallis tests (p=0.05). Results: All retreatment techniques used in this study left some filling material inside the root canal. Images in buccolingual and mesiodistal directions showed no significant differences between the groups (p>0.05). Conclusions: Under the experimental conditions, the remaining filling material after retreatment was similar for each group. Key words:Gutta-percha removal, K3®, NiTi, R-Endo®. PMID:22143729

  10. Do NiTi instruments show defects before separation? Defects caused by torsional fatigue in hand and rotary nickel-titanium (NiTi) instruments which lead to failure during clinical use.

    Science.gov (United States)

    Chakka, N V Murali Krishna; Ratnakar, P; Das, Sanjib; Bagchi, Anandamy; Sudhir, Sudhir; Anumula, Lavanya

    2012-11-01

    Visual and microscopic evaluation of defects caused by torsional fatigue in hand and rotary nickel titanium (NiTi) instruments. Ninety-six NiTi greater taper instruments which were routinely used for root canal treatment only in anterior teeth were selected for the study. The files taken include ProTaper for hand use, ProTaper Rotary files and Endowave rotary files. After every use, the files were observed visually and microscopically (Stereomicroscope at 10×) to evaluate the defects caused by torsional fatigue. Scoring was given according to a new classification formulated which gives an indication of the severity of the defect or damage. Data was statistically analyzed using KruskallWallis and Mann-Whitney U test. Number of files showing defects were more under stereomicroscope than visual examination. But, the difference in the evaluation methods was not statistically significant. The different types of defects observed were bent instrument, straightening/stretching of twist contour and partial reverse twisting. Endowave files showed maximum number of defects followed by ProTaper for hand use and least in ProTaper Rotary. Visible defects due to torsional fatigue do occur in NiTi instruments after clinical use. Both visual and microscopic examinations were efficient in detecting defects caused due to torsional fatigue. This study emphasizes that all files should be observed for any visible defects before and after every instrumentation cycle to minimize the risk of instrument separation and failure of endodontic therapy.

  11. ProFile Vortex and Vortex Blue Nickel-Titanium Rotary Instruments after Clinical Use.

    Science.gov (United States)

    Shen, Ya; Zhou, Huimin; Coil, Jeffrey M; Aljazaeri, Bassim; Buttar, Rene; Wang, Zhejun; Zheng, Yu-feng; Haapasalo, Markus

    2015-06-01

    The aim of this study was to analyze the incidence and mode of ProFile Vortex and Vortex Blue instrument defects after clinical use in a graduate endodontic program and to examine the impact of clinical use on the instruments' metallurgical properties. A total of 330 ProFile Vortex and 1136 Vortex Blue instruments from the graduate program were collected after each had been used in 3 teeth. The incidence and type of instrument defects were analyzed. The lateral surfaces and fracture surfaces of the fractured files were examined by using scanning electron microscopy. Unused and used instruments were examined by full and partial differential scanning calorimetry. No fractures were observed in the 330 ProFile Vortex instruments, whereas 20 (6.1%) revealed bent or blunt defects. Only 2 of the 1136 Vortex Blue files fractured during clinical use. The cause of fracture was shear stress. The fractures occurred at the tip end of the spirals. Only 1.8% (21 of 1136) of the Vortex Blue files had blunt tips. Austenite-finish temperatures were very similar for unused and used ProFile Vortex files and were all greater than 50°C. The austenite-finish temperatures of used and unused Vortex Blue files (38.5°C) were lower than those in ProFile Vortex instruments (P Vortex Blue files had an obvious 2-stage transformation, martensite-to-R phase and R-to-austenite phase. The trends of differential scanning calorimetry plots of unused Vortex Blue instruments and clinically used instruments were very similar. The risk of ProFile Vortex and Vortex Blue instrument fracture is very low when instruments are discarded after clinical use in the graduate endodontic program. The Vortex Blue files have metallurgical behavior different from ProFile Vortex instruments. Copyright © 2015 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  12. Conditioning of root canal anatomy on static and dynamics of nickel-titanium rotary instruments

    Directory of Open Access Journals (Sweden)

    Italo Di Giuseppe

    2015-11-01

    Conclusions: Therefore, in some cases, we would need an instrument that can reconcile efficiency with a reduction of mass and torque; the ideal instrument should have a very contained working part, combining efficiency with the decrease of mass and, consequently, of torsional stresses too.

  13. A comparison of nickel-titanium rotary instruments manufactured using different methods and cross-sectional areas: ability to resist cyclic fatigue.

    Science.gov (United States)

    Oh, So-Ram; Chang, Seok-Woo; Lee, Yoon; Gu, Yu; Son, Won-Jun; Lee, Woocheol; Baek, Seung-Ho; Bae, Kwang-Shik; Choi, Gi-Woon; Lim, Sang-Min; Kum, Kee-Yeon

    2010-04-01

    This study examined the effect of the manufacturing methods (ground, electropolished, and twisted) and the cross-sectional area (CSA) of nickel-titanium (NiTi) rotary instruments on their cyclic fatigue resistance. A total of 80 NiTi rotary instruments (ISO 25/.06 taper) from 4 brands (K3, ProFile, RaCe, and TF) were rotated in a simulated root canal with pecking motion until fracture. The number of cycles to failure (NCF) was calculated. The CSA at 3 mm from the tip of new instruments of each brand was calculated. The correlation between the CSA and NCF was evaluated. All fractured surfaces were analyzed using a scanning electron microscope to determine the fracture mode. The TF instruments were the most resistant to fatigue failure. The resistance to cyclic failure increased with decreasing CSA. All fractured surfaces showed the coexistence of ductile and brittle properties. The CSA had a significant effect on the fatigue resistance of NiTi rotary instruments. Copyright 2010 Mosby, Inc. All rights reserved.

  14. Comparative Evaluation of Smear Layer and Debris on the Canal Walls prepared with a Combination of Hand and Rotary ProTaper Technique using Scanning Electron Microscope.

    Science.gov (United States)

    Kiran, S; Prakash, Sandeep; Siddharth, Pujari R; Saha, Supradip; Geojan, Naiza E; Ramachandran, Mookambika

    2016-07-01

    The effect of smear layer and debris on the success rate of endodontic treatment has not yet been definitely determined. So the present study was aimed to evaluate the amount of smear layer and debris on the canal walls prepared with a combination of hand and rotary ProTaper technique using NaOCl and ethylenediaminetetraacetic acid (EDTA) alternately as root canal irrigants using scanning electron microscope (SEM). Eighty intact freshly extracted human permanent mandibular premolar teeth were collected and randomly divided equally into four groups. In group I canals were prepared with hand K-Flexofiles; group II with rotary ProTaper instruments; group III with rotary ProTaper instruments and final instrumentation was done with hand K-Flexofile; group IV with rotary ProTaper instruments and final instrumentation was done with RC-Prep and irrigated with 1 mL of normal saline. In all groups canals were irrigated using NaOCl and EDTA alternately. After instrumentation, the teeth were prepared for SEM examination using five-score indices for debris and smear layer at coronal, middle, and apical third levels. Statistical analysis was performed using chi-square test (p hand files after automated rotary preparation could result in cleaner canal walls. Alternate irrigation with NaOCl and EDTA is effective in the removal of debris and smear layer in the coronal and middle level, but the effectiveness in the apical third is less.

  15. Effect of environment on fatigue failure of controlled memory wire nickel-titanium rotary instruments.

    Science.gov (United States)

    Shen, Ya; Qian, Wei; Abtin, Houman; Gao, Yuan; Haapasalo, Markus

    2012-03-01

    This study examined the fatigue behavior of 2 types of nickel-titanium (NiTi) instruments made from a novel controlled memory NiTi wire (CM wire) under various environment conditions. Three conventional superelastic NiTi instruments of ProFile (Dentsply Maillefer, Ballaigues, Switzerland), Typhoon (Clinician's Choice Dental Products, New Milford, CT), and DS-SS0250425NEYY (Clinician's Choice Dental Products) and 2 new CM wire instruments of Typhoon CM and DS-SS0250425NEYY CM were subjected to rotational bending at the curvature of 35° in air, deionized water, 17% EDTA, or deionized water after immersion in 6% sodium hypochlorite for 25 minutes, and the number of revolutions of fracture (N(f)) was recorded. The fracture surface of all fragments was examined by a scanning electron microscope. The crack-initiation sites and the percentage of dimple area to the whole fracture cross-section were noted. Two new CM Wire instruments yielded an improvement of >4 to 9 times in N(f) than conventional NiTi files with the same design under various environments (P Wire instruments was significantly longer in liquid media than in air (P wire had one crack origin. The values of the area fraction occupied by the dimple region were significantly smaller on CM NiTi instruments than in conventional NiTi instruments under various environments (P < .05). Within the limitations of this study, the type of NiTi metal alloy (CM files vs conventional superelastic NiTi files) influences the cyclic fatigue resistance under various environments. The fatigue life of CM instruments is longer in liquid media than in air. Copyright © 2012 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  16. Metallurgical characterization of M-Wire nickel-titanium shape memory alloy used for endodontic rotary instruments during low-cycle fatigue.

    Science.gov (United States)

    Ye, Jia; Gao, Yong

    2012-01-01

    Rotary instruments made of a new nickel-titanium (NiTi) alloy (M-Wire) have shown improved cyclic fatigue resistance and mechanical properties compared with those made of conventional superelastic NiTi wires. The objective of this study was to characterize microstructural changes of M-Wire throughout the cyclic fatigue process under controlled strain amplitude. The average fatigue life was calculated from 30 M-Wire samples that were subjected to a strain-controlled (≈ 4%) rotating bend fatigue test at room temperature and rotational speed of 300 rpm. Microstructural evolution of M-Wire has been investigated by different metallurgical characterization techniques, including differential scanning calorimetry, Vickers microhardness, and transmission electron microscopy at 4 different stages (as-received state, 30%, 60%, and 90% of average fatigue life). During rotating bend fatigue test, no statistically significant difference (P > .05) was found on austenite finish temperatures between as-received M-Wire and fatigued samples. However, significant differences (P Wire are expected to have higher strength and wear resistance than similar instruments made of conventional superelastic NiTi wires because of its unique nano-crystalline martensitic microstructure. Copyright © 2012 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  17. A new method for the assessment of the surface topography of NiTi rotary instruments.

    Science.gov (United States)

    Ferreira, F; Barbosa, I; Scelza, P; Russano, D; Neff, J; Montagnana, M; Zaccaro Scelza, M

    2017-09-01

    To describe a new method for the assessment of nanoscale alterations in the surface topography of nickel-titanium endodontic instruments using a high-resolution optical method and to verify the accuracy of the technique. Noncontact three-dimensional optical profilometry was used to evaluate defects on a size 25, .08 taper reciprocating instrument (WaveOne ® ), which was subjected to a cyclic fatigue test in a simulated root canal in a clear resin block. For the investigation, an original procedure was established for the analysis of similar areas located 3 mm from the tip of the instrument before and after canal preparation to enable the repeatability and reproducibility of the measurements with precision. All observations and analysis were taken in areas measuring 210 × 210 μm provided by the software of the equipment. The three-dimensional high-resolution image analysis showed clear alterations in the surface topography of the examined cutting blade and flute of the instrument, before and after use, with the presence of surface irregularities such as deformations, debris, grooves, cracks, steps and microcavities. Optical profilometry provided accurate qualitative nanoscale evaluation of similar surfaces before and after the fatigue test. The stability and repeatability of the technique enables a more comprehensive understanding of the effects of wear on the surface of endodontic instruments. © 2016 International Endodontic Journal. Published by John Wiley & Sons Ltd.

  18. The effect of educational intervention on the adoption of nickel-titanium rotary instrumentation in a Public Dental Service.

    Science.gov (United States)

    Reit, C; Bergenholtz, G; Caplan, D; Molander, A

    2007-04-01

    To study the influence of two educational programmes on the adoption of nickel-titanium rotary instrumentation (NTRI) amongst general dental practitioners in a short-term as well as a long-term perspective. All dentists employed in the Gothenburg Dental service (n = 148) were enrolled in the study. The clinics in the organization were randomly assigned to one of two educational programmes. In the first programme a 4-h lecture on root canal instrumentation was given. In the second programme the lecture course was supplemented by a 6-h hands-on training session. The short-term effect was measured by a questionnaire distributed 6 months after completed education. The long-term effect was evaluated 4 years later. The overall utilization rate of NTRI increased from 4% to 73%. However, lectures in combination with hands-on training resulted in a better short-term acceptance rate (94%) than if teaching was given only in lecture-format (53%) (P = 0.000). As a consequence, all staff were offered hands-on training. The long-term adoption rate was 88%. Reasons for accepting the new technology usually were found within the 'relative advantage' category. Common reasons for dentists not to adopt NTRI were that they could not get started or that they found no advantage over the old technology. The short-term adoption of a new technology might be influenced by the design of an introductory educational programme. For clinical procedures, such as root canal instrumentation, the inclusion of hands-on training sessions seems to be important to reach a high acceptance rate.

  19. The Effects of NiTi Hand and Rotary Canal Master U and K-Flex Instrumentation of Root Canal Morphology

    Science.gov (United States)

    1992-09-01

    Rotary Canal Master "U" and K-Flex Instrumentation of Root Canal Morphology 6. AUTHOR(S) Robert H. Haller 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES... endodontic failure. B. STATET OF THE PREL]2U Conventional endodontic instruments have re.nained basically unchanged since the introduction of the K-type...F;hcw"e that this nO𔃾 instruneent destim tended ti- produce rounder pr rMticns with • t!-rnnVortaticn than c rnvrnticnal 4 endodontic instruments

  20. Evaluation of the resistance to cyclic fatigue among ProTaper Next, ProTaper Universal, and Vortex Blue rotary instruments.

    Science.gov (United States)

    Nguyen, Harrison H; Fong, Hanson; Paranjpe, Avina; Flake, Natasha M; Johnson, James D; Peters, Ove A

    2014-08-01

    The purpose of this study was to compare the fracture resistance to cyclic fatigue of ProTaper Next (PTN; Dentsply Tulsa Dental Specialties, Tulsa, OK), ProTaper Universal (PTU, Dentsply Tulsa Dental Specialties), and Vortex Blue (VB, Dentsply Tulsa Dental Specialties) rotary instruments. Twenty instruments each of PTN X1-X5, PTU S1-F5, and VB 20/04-50/04 were rotated until fracture in a simulated canal of 90° and a 5-mm radius using a custom-made testing platform. The number of cycles to fracture (NCF) was calculated. Weibull analysis was used to predict the maximum number of cycles when 99% of the instrument samples survive. VB 20/04-30/04 had significantly higher NCF than PTU S1-F5 and PTN X1-X5. VB 35/04-45/04 had significantly higher NCF than PTU S2-F5 and PTN X2-X5. PTN X1 had higher NCF than PTU S1-F5. PTN X2 had higher NCF than PTU F2-F5. The Weibull distribution predicted the highest number of cycles at which 99% of instruments survive to be 766 cycles for VB 25/04 and the lowest to be 50 cycles for PTU F2. Under the limitations of this study, VB 20/04-45/04 were more resistant to cyclic fatigue than PTN X2-X5 and PTU S2-F5. PTN X1 and X2 were more resistant to cyclic fatigue than PTU F2-F5. The Weibull distribution appears to be a feasible and potentially clinically relevant model to predict resistance to cyclic fatigue. Copyright © 2014 American Association of Endodontists. All rights reserved.

  1. Micro-computed Tomographic Analysis of Apical Microcracks before and after Root Canal Preparation by Hand, Rotary, and Reciprocating Instruments at Different Working Lengths.

    Science.gov (United States)

    de Oliveira, Bruna Paloma; Câmara, Andréa Cruz; Duarte, Daniel Amancio; Heck, Richard John; Antonino, Antonio Celso Dantas; Aguiar, Carlos Menezes

    2017-07-01

    This study aimed to compare apical microcrack formation after root canal shaping by hand, rotary, and reciprocating files at different working lengths using micro-computed tomographic analysis. Sixty mandibular incisors were randomly divided into 6 experimental groups (n = 10) according to the systems and working lengths used for the root canal preparation: ProTaper Universal for Hand Use (Dentsply Maillefer, Ballaigues, Switzerland), HyFlex CM (Coltene-Whaledent, Allstetten, Switzerland), and Reciproc (VDW, Munich, Germany) files working at the apical foramen (AF) and 1 mm short of the AF (AF - 1 mm). The teeth were imaged with micro-computed tomographic scanning at an isotropic resolution of 14 μm before and after root canal preparation, and the cross-sectional images generated were assessed to detect microcracks in the apical portion of the roots. Overall, 17 (28.3%) specimens presented microcracks before instrumentation. Apical microcracks were present in 1 (ProTaper Universal for Hand Use), 3 (Hyflex CM), and 2 (Reciproc) specimens when the instrumentation terminated at the AF. When instrumentation was terminated at AF - 1 mm, apical microcracks were detected in 3 (ProTaper Universal for Hand Use) and 4 (Hyflex CM and Reciproc) specimens. All these microcracks detected after root canal preparation were already present before instrumentation, and no new apical microcrack was visualized. For all groups, the number of slices presenting microcracks after root canal preparation was the same as before canal preparation. Root canal shaping with ProTaper Universal for Hand Use, HyFlex CM, and Reciproc systems, regardless of the working length, did not produce apical microcracks. Copyright © 2017 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  2. A comparison of root surface instrumentation using manual, ultrasonic and rotary instruments: An in vitro study using scanning electron microscopy

    Directory of Open Access Journals (Sweden)

    Preeti Marda

    2012-01-01

    Results and Conclusion: The RCI and LTSI showed nonsignificant differences between the three groups. RLTSI showed a significant difference between Slimline™ and hand curette as well as Slimline™ and Desmo-Clean™. Slimline™ showed the least mean scores for RCI, LTSI, and RLTSI. Thus, even though the difference was not statistically significant, Slimline™ insert was shown to be better than the other methods as assessed by the indices scores and the instrumentation time.

  3. Cross-sectional evaluation of post-operative pain and flare-ups in endodontic treatments using a type of rotary instruments.

    Science.gov (United States)

    Tanalp, Jale; Sunay, Hakki; Bayirli, Gündüz

    2013-01-01

    The purpose of this clinical study was to evaluate the general incidence of post-operative pain and flare-ups in patients who were endodontically treated by two endodontics specialists using rotary instruments (Hero 642, Micro Mega, France) with the same treatment protocol. Records of 382 teeth belonging to 268 patients treated by two endodontics specialists during a 6-month period were kept and evaluated. Post-operative pain between treatment visits was categorized using a pre-established scoring system. Ninety-five patients were males, whereas 173 were females. Pulpal necrosis without periapical pathosis was determined as the most common indication for endodontic treatment (21.7%) followed by irreversible pulpitis and re-treatment without periapical lesions (18.3%, 18.3%, respectively). The general prevalence of post-operative pain and flare-ups was determined as 8.1%, whereas cases that could be classified as real flare-ups which were severe and required an unscheduled visit (scores 2 and 3) comprised 3.4% of the cases. No statistically significant correlation was determined between gender and post-operative pain and flare-up (p = 0.05). There was a significant correlation between number of appointments and the presence of pain and flare-ups. Teeth undergoing multiple visits had a higher risk of developing post-operative pain and flare-ups compared to those with single appointments with a statistical significance (p = 0.03). Teeth with pre-operative pain were more prone to developing post-operative pain and discomfort with a statistically significant difference (p = 0.02). While no significant correlation was determined between tooth vitality and pain and flare-ups (p = 0.5), a statistically significant relationship existed between the presence of a periapical pathosis and post-operative pain and flare-ups. Cases with a periapical lesion had a higher risk of developing pain and flare-ups compared to those with no periapical involvement (p = 0.0001). Future

  4. In vitro evaluation of apical extrusion of bacteria following use of new rotary instrumentation system.

    Science.gov (United States)

    Mohammadi, Zahed

    2009-04-01

    The aim of this study was to evaluate the number of bacteria extruded apically from extracted teeth ex vivo after canal instrumentation using two engine-driven nickel-titanium instruments (Flex Master and V-Taper). Seventy extracted maxillary central incisor teeth were used. After preparing access cavities, root canals were contaminated with a suspension of Enterococcus faecalis, then dried. The contaminated roots were divided into two experimental groups of 30 teeth each and one control group of 10 teeth. Bacteria extruded from the apical foramen during instrumentation were collected into vials. The microbiological samples from the vials were incubated in culture media for 24 hours. Colonies of bacteria were counted, and the results were given as number of colony-forming units. The data obtained were analyzed using the Kruskal-Wallis one-way analysis of variance and Mann-Whitney U-tests, with alpha = 0.05 as the level for statistical significance. Results showed that there was no significant difference as to the number of extruded bacteria between the two engine-driven systems (P > 0.05). Both engine-driven nickel-titanium systems extruded bacteria through the apical foramen.

  5. Efficacy of two rotary retreatment systems in removing Gutta-percha and sealer during endodontic retreatment with or without solvent: A comparative in vitro study.

    Science.gov (United States)

    Bhagavaldas, Moushmi Chalakkarayil; Diwan, Abhinav; Kusumvalli, S; Pasha, Shiraz; Devale, Madhuri; Chava, Deepak Chowdary

    2017-01-01

    The aim of this in vitro study was to compare the efficacy of two retreatment rotary systems in the removal of Gutta-percha (GP) and sealer from the root canal walls with or without solvent. Forty-eight extracted human mandibular first premolars were prepared and obturated with GP and AH Plus sealer. Samples were then randomly divided into four groups. Group I was retreated with MtwoR rotary system without solvent, Group II was retreated with MtwoR rotary system with Endosolv R as the solvent, Group III with D-RaCe rotary system without solvent, and Group IV with D-RaCe rotary system and Endosolv R solvent. The cleanliness of canal walls was determined by stereomicroscope (×20) and AutoCAD software. Kruskal-Wallis test and Mann-Whitney U-test were used to compare the data. Results showed that none of the retreatment systems used in this study was able to completely remove the root canal filling material. D-RaCe with or without solvent showed significantly ( P > 0.05) less filling material at all levels compared to MtwoR with/without solvent. Within the limitation of the current study, D-RaCe rotary retreatment system is more effective in removing filling material from root canal walls when compared to MtwoR rotary retreatment system.

  6. Evaluation of debris extruded apically during the removal of root canal filling material using ProTaper, D-RaCe, and R-Endo rotary nickel-titanium retreatment instruments and hand files.

    Science.gov (United States)

    Topçuoğlu, Hüseyin Sinan; Aktı, Ahmet; Tuncay, Öznur; Dinçer, Asiye Nur; Düzgün, Salih; Topçuoğlu, Gamze

    2014-12-01

    The aim of this study was to evaluate the amount of debris extruded apically during the removal of root canal filling material using ProTaper (Dentsply Maillefer, Ballaigues, Switzerland), D-RaCe (FKG Dentaire, La Chaux-de-Fonds, Switzerland), and R-Endo (Micro-Mega, Besançon, France) nickel-titanium (NiTi) rotary retreatment instruments and hand files. Sixty extracted single-rooted mandibular premolar teeth were prepared with K-files and filled with gutta-percha and AH Plus sealer (Dentsply DeTrey, Konstanz, Germany). The teeth were then randomly assigned to 4 groups (n = 15 for each group) for retreatment. The removal of canal filling material was performed as follows: hand files, ProTaper, D-RaCe, and R-Endo retreatment instruments. Debris extruded apically during the removal of canal filling material was collected into preweighed Eppendorf tubes. The tubes were then stored in an incubator at 70°C for 5 days. The weight of the dry extruded debris was established by subtracting the preretreatment and postretreatment weight of the Eppendorf tubes for each group. The data obtained were analyzed using 1-way analysis of variance and Tukey post hoc tests. All retreatment techniques caused the apical extrusion of debris. Hand files produced significantly more debris when compared with ProTaper, D-RaCe, and R-Endo rotary systems (P ProTaper, D-RaCe, and R-Endo retreatment systems (P > .05). The findings showed that during the removal of root canal filling material, rotary NiTi retreatment instruments used in this study caused less apical extrusion of debris compared with hand files. Copyright © 2014 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  7. Influence of the geometry of curved artificial canals on the fracture of rotary nickel-titanium instruments subjected to cyclic fatigue tests.

    Science.gov (United States)

    Lopes, Hélio P; Vieira, Márcia V B; Elias, Carlos N; Gonçalves, Lucio S; Siqueira, José F; Moreira, Edson J L; Vieira, Victor T L; Souza, Letícia C

    2013-05-01

    This study evaluated the influence of different features of canal curvature geometry on the number of cycles to fracture of a rotary nickel-titanium endodontic instrument subjected to a cyclic fatigue test. BioRaCe BR4C instruments (FKG Dentaire, La Chaux-de Fonds, Switzerland) were tested in 4 grooves simulating curved metallic artificial canals, each one measuring 1.5 mm in width, 20 mm in total length, and 3.5 mm in depth with a U-shaped bottom. The parameters of curvature including the radius and arc lengths and the position of the arc differed in the 4 canal designs. Fractured surfaces and helical shafts of the separated instruments were analyzed by scanning electron microscopy. The Student's t test showed that a significantly lower number of cycles to fracture values were observed for instruments tested in canals with the smallest radius, the longest arc, and the arc located in the middle portion of the canal. Scanning electron microscopic analysis of the fracture surfaces revealed morphologic characteristics of ductile fracture. Plastic deformation was not observed in the helical shaft of the fractured instruments. Curvature geometry including the radius and arc lengths and the position of the arc along the root canal influence the number of cycles to fracture of rotary nickel-titanium instruments subjected to flexural load. Copyright © 2013 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  8. A comparative evaluation of gutta percha removal and extrusion of apical debris by rotary and hand files.

    Science.gov (United States)

    Chandrasekar; Ebenezar, A V Rajesh; Kumar, Mohan; Sivakumar, A

    2014-11-01

    The aim of this study was to evaluate the efficacy of Protaper retreatment files in comparison with RaCe, K3 and H-files for removal of gutta-percha and apically extruded debris using volumetric analysis. Forty extracted single rooted maxillary incisor teeth with straight canals and mature apices were selected for the study. After access cavity preparation, apical patency was confirmed with a size 10 K-file extending 1mm beyond the point at which it was first visible at the apical end. Working lengths were determined with the use of size 15 K-file. The canals were prepared in a step-back technique and the master apical file was size 30 for all teeth. 3% sodium hypochlorite was used as an irrigant after each instrumentation. Before final rinse, size 20 K-file was passed 1mm beyond the apex to remove any dentinal shaving plugs and maintain the apical patency. Then the canals were dried with paper points. The root canal was filled using standard gutta-percha points and zinc oxide eugenol sealer under lateral condensation technique. The teeth were then randomly divided into four groups of ten teeth each based on the instrument used for gutta percha removal. All the rotary instruments used in this study were rotated at 300rpm. The instruments used were: Group 1 - RaCe Files, Group 2 - ProTaper retreatment Files, Group 3 - K3 Files and Group 4 - H Files. The volume of the obturating material was calculated before and after removal using volumetric analysis with spiral CT. The removal efficacy with each instrument was calculated and statistically analysed. The results of the study show that the ProTaper retreatment files (Group 2) (97.4%) showed the highest efficiency in the removal of obturating material, which was followed by RaCe (95.74%), K3 (92.86%) and H files (90.14%) with the efficiency in the decreasing order. Similarly the mean apical extrusion in H files (0.000 ± 0.002) was significantly lower than all the rotary instruments. However, the difference among the

  9. Fracture resistance of dental nickel–titanium rotary instruments with novel surface treatment: Thin film metallic glass coating

    Directory of Open Access Journals (Sweden)

    Chih-Wen Chi

    2017-05-01

    Conclusion: The novel surface treatment of Ti-Zr-B thin film metallic glass on dental NiTi rotary files can effectively improve the fatigue fracture resistance by offering a smooth coated surface with amorphous microstructure.

  10. The influence of torque and manual glide path on the defect or separation rate of NiTi rotary instruments in root canal therapy

    Directory of Open Access Journals (Sweden)

    Zarrabi M

    2010-01-01

    Full Text Available Introduction: One of the effecting factors in prognosis of root canal therapy is accidental procedure as broken files that may be unpreventable. Many manufacturers have designed and marketed various electromotors that can control rotational speed and torque. On the other hand, some studies have recommended applying a manual glide path to diminish contact area between the file and canal walls. The purpose of this study was evaluation of the effect of torque and a manual glide path on defects as separation of Nickel-titanium (NiTi rotary files. Materials and Methods: This ex vivo randomized controlled trial study was carried out on 160 canals of human′s matured molars with mild curvature (15-338. After initial preparation of samples and checking for inclusion criteria, in first group, preparation was carried out with air-driven handpiece, and in group two, Endo IT was used as electromotor. In both groups, Mtwo files with simultaneous technique were used for preparation. Then all data were collected and analyzed with Mann Whitny, Mantel Cox, and t-test. Results: No significant differences between two groups (P < 0.05 were observed. Based on survival analysis, safety probability of files after preparation of nine canals is 64% in group one and 69.9% in group two. There was no significant differences between this safety probability in two groups (P = 0.272. Conclusion: Usage of torque control handpiece is not an important factor, comparing instrumentation technique.

  11. Wear analysis and cyclic fatigue resistance of electro discharge machined NiTi rotary instruments

    Directory of Open Access Journals (Sweden)

    F. Iacono

    2016-06-01

    Conclusions: The typical irregular surface of HyFlex EDM remained unaffected after multiple uses, confirming a high wear resistance. The new manufacturing process of electrical discharge machining had a substantial impact on fatigue lifetime of EDM files when compared with HyFlex CM. Within limitations of the present in vitro results, EDM files appeared suitable in shaping severely curved canals.

  12. The influence of simulated clinical use on the flexibility of rotary ProTaper Universal, K3 and EndoSequence nickel-titanium instruments.

    Science.gov (United States)

    Viana, A C D; Pereira, E S J; Bahia, M G A; Buono, V T L

    2013-09-01

    To investigate the influence of cyclic flexural and torsional loading on the flexibility of ProTaper Universal, K3 and EndoSequence nickel-titanium instruments, in view of the hypothesis that these types of loading would decrease the flexibility of the selected NiTi rotary files. The instruments evaluated were S2 and F1 ProTaper Universal, sizes 20 and 25, .06 taper K3, and sizes 20 and 25, .06 taper EndoSequence. Flexibility was determined by 45° bending tests according to ISO 3630-1 specification. Values of the bending moment (MB ) obtained with new instruments were considered as the control group (CG). Bending tests were then conducted in instruments previously fatigued to one-fourth and three-fourths of their average fatigue life (fatigue groups, FG¼ and FG¾), as well as after cyclic torsional loading (torsional group, TG). Fatigue tests were carried out in a bench device that allowed the files to rotate freely inside an artificial canal with an angle of curvature of 45° and a radius of 5 mm. Cyclic torsional loading tests were performed that entailed rotating the instrument from zero angular deflection to 180° and then returning to zero applied torque in 20 cycles. Data were analysed using one-way analysis of variance at a significance level of 5%. Simulated clinical use by means of flexural fatigue tests did not affect the flexibility of the instruments, except for a significant increase in flexibility observed in a few instruments (P instruments and after cyclic torsional loading showed no significant differences between them (P > 0.05). The flexibility of rotary ProTaper Universal, K3 and EndoSequence NiTi instruments, measured in bending tests, was not adversely affected by simulated clinical use in curved root canals. © 2013 International Endodontic Journal. Published by John Wiley & Sons Ltd.

  13. Micro-CT evaluation of the effectiveness of the combined use of rotary and hand instrumentation in removal of Resilon.

    Science.gov (United States)

    Asheibi, Fatma; Qualtrough, Alison J E; Mellor, Anthony; Withers, Philip J; Lowe, Tristan

    2014-01-01

    This study compares the effectiveness of ProTaper rotary files with ProTaper retreatment and K-files in the removal of Resilon or gutta percha (GP) from canals filled either by cold lateral condensation or thermal obturation using micro-CT. Ninety-six teeth were prepared using ProTaper files and allocated into four groups (n=24): Group-1 was filled with GP/AH-Plus and Group-2 with Resilon/RealSeal using cold lateral condensation. Group-3 was filled with GP/AH-Plus and Group-4 with Resilon/RealSeal using System B and Obtura II. The roots were scanned by micro-CT. Each group was divided into two subgroups (n=12): A, retreated using ProTaper files and B, using ProTaper retreatment and K-files. The roots were scanned to calculate the volume of the remaining material. With thermal obturation, roots filled with Resilon had significantly more remaining material than GP. Obturation using thermal technique resulted in significantly less remaining material than cold condensation except Resilon retreated using ProTaper retreatment and K-files.

  14. Comparison of Manual and Rotary Instrumentation on Postoperative Pain in Teeth with Asymptomatic Irreversible Pulpitis: A Randomized Clinical Trial

    Science.gov (United States)

    Talebzadeh, Bita; Nezafati, Saeed; Rahimi, Saeed; Shahi, Shahriar; Lotfi, Mehrdad; Ghasemi, Negin

    2016-01-01

    Introduction: One of the most common complications of root canal treatment is postoperative pain. The aim of the present clinical trial was to compare the severity of postoperative pain after root canal preparation with RaCe rotary system and hand K-Flexofile. Methods and Materials: A total of 96 mandibular first and second molars were divided into two groups (n=48) based on root canal preparation technique. The teeth in both groups underwent one-session root canal treatment and the severity of postoperative pain was evaluated using visual analog scale (VAS) at 4-, 8-, 12-, 24- and 48-h and 1-week intervals. In addition, the type and dosage of analgesics were recorded. Data were analyzed with repeated-measures ANOVA. Statistical significance was set at 0.05. Results: The difference between the two groups during this period and at subsequent intervals were not significant (P>0.05). There were no significant differences between the two groups in type and the number of analgesics in pain-free subjects (P=0.12 and P=0.61, respectively). Conclusion: There were no statistically significant differences in pain severity between the two groups at any intervals. PMID:27790255

  15. Flexibility and torsional behaviour of rotary nickel-titanium PathFile, RaCe ISO 10, Scout RaCe and stainless steel K-File hand instruments.

    Science.gov (United States)

    Nakagawa, R K L; Alves, J L; Buono, V T L; Bahia, M G A

    2014-03-01

    To assess and compare the flexibility and torsional resistance of PathFile, RaCe ISO 10 and Scout RaCe instruments in relation to stainless steel K-File hand instruments. Rotary PathFile (sizes 13, 16 and 19; .02 taper), Race ISO 10 (size 10; 0.02, 0.04 and 0.06 tapers), Scout RaCe (sizes 10, 15 and 20; 0.02 taper) and hand K-File (sizes 10, 15 and 20; 0.02 taper) instruments were evaluated. Alloy chemical composition, phases present and transformation temperatures were determined for the NiTi instruments. For all instruments, diameters at each millimetre from the tip as well as cross-sectional areas at 3 mm from the tip were measured based on ANSI/ADA Specification No. 101 using image analysis software. Resistance to bending and torsional resistance were determined according to specification ISO 3630-1. Vickers microhardness measurements were also taken in all instruments to assess their strength. Data were analysed using analysis of variance (α = 0.05). The alloys used in the manufacture of the three types of NiTi instruments had approximately the same chemical composition, but the PathFile instruments had a higher Af transformation temperature and contained a small amount of B19' martensite. All instruments had diameter values within the standard tolerance. The bending and torsional resistance values were significantly increased relative to the instrument diameter and cross-sectional area. PathFile instruments were the most flexible and the least torque resistant, whilst the stainless steel instruments were the least flexible although they were more torque resistant than the NiTi instruments. © 2013 International Endodontic Journal. Published by John Wiley & Sons Ltd.

  16. An In Vitro Comparative Study of Intracanal Fluid Motion and Wall Shear Stress Induced by Ultrasonic and Polymer Rotary Finishing Files in a Simulated Root Canal Model

    OpenAIRE

    Koch, Jon; Borg, John; Mattson, Abby; Olsen, Kris; Bahcall, James

    2012-01-01

    Objective. This in vitro study compared the flow pattern and shear stress of an irrigant induced by ultrasonic and polymer rotary finishing file activation in an acrylic root canal model. Flow visualization analysis was performed using an acrylic canal filled with a mixture of distilled water and rheoscopic fluid. The ultrasonic and polymer rotary finishing file were separately tested in the canal and activated in a static position and in a cyclical axial motion (up and down). Particle moveme...

  17. Cyclic fatigue resistance of XP-endo Shaper compared with different nickel-titanium alloy instruments.

    Science.gov (United States)

    Elnaghy, Amr; Elsaka, Shaymaa

    2018-04-01

    The aims of this study were to assess and compare the resistance to cyclic fatigue of XP-endo Shaper (XPS; FKG Dentaire, La Chaux-de-Fonds, Switzerland) instruments with TRUShape (TRS; Dentsply Tulsa Dental Specialties, Tulsa, OK, USA), HyFlex CM (HCM; Coltene, Cuyahoga Falls, OH, USA), Vortex Blue (VB; Dentsply Tulsa Dental Specialties), and iRace (iR; FKG Dentaire) nickel-titanium rotary instruments at body temperature. Size 30, 0.01 taper of XPS, size 30, 0.04 taper of HCM, VB, iR, and size 30, 0.06 taper of TRS instruments were immersed in saline at 37 ± 1 °C during cyclic fatigue testing. The instruments were tested with 60° angle of curvature and a 3-mm radius of curvature. The number of cycles to failure (NCF) was calculated and the length of the fractured segment was measured. Fractographic examination of the fractured surface was performed using a scanning electron microscope. The data were analyzed statistically using Kruskal-Wallis H test and Mann-Whitney U tests. Statistical significance was set at P ductile fracture of cyclic fatigue failure. XPS instruments exhibited greater cyclic fatigue resistance compared with the other tested instruments. XP-endo Shaper instruments could be used more safely in curved canals due to their higher fatigue resistance.

  18. A comparative evaluation of efficacy of protaper universal rotary retreatment system for gutta-percha removal with or without a solvent.

    Science.gov (United States)

    Kumar, M Sita Ram; Sajjan, Girija S; Satish, Kalyan; Varma, K Madhu

    2012-09-01

    The aim was to evaluate and compare the efficacy of ProTaper Universal rotary retreatment system with or without solvent and stainless steel hand files for endodontic filling removal from root canals and also to compare retreatment time for each system. Thirty extracted mandibular premolars with single straight canals were endodontically treated. Teeth were divided into three major groups, having 10 specimens each. Removal of obturating material in group 1 by stainless steel hand files with RC Solve, group 2 by ProTaper Universal retreatment instruments and group 3 by ProTaper Universal retreatment instruments along with RC solve was done. Retreatment was considered complete for all groups when no filling material was observed on the instruments. The retreatment time was recorded for each tooth. All specimens were grooved longitudinally in a buccolingual direction. The split halves were examined under a stereomicroscope and images were captured and analyzed. The remaining filling debris area ratios were considered for statistical analysis. With ANOVA test, statistical analysis showed that there was statistically no significant difference regarding the amount of filling remnants between the groups (P ProTaper Universal retreatment system files alone proved to be faster than the other experimental groups.

  19. A comparative evaluation of efficacy of protaper universal rotary retreatment system for gutta-percha removal with or without a solvent

    Directory of Open Access Journals (Sweden)

    M Sita Ram Kumar

    2012-01-01

    Full Text Available Aim: The aim was to evaluate and compare the efficacy of ProTaper Universal rotary retreatment system with or without solvent and stainless steel hand files for endodontic filling removal from root canals and also to compare retreatment time for each system. Materials and Methods: Thirty extracted mandibular premolars with single straight canals were endodontically treated. Teeth were divided into three major groups, having 10 specimens each. Removal of obturating material in group 1 by stainless steel hand files with RC Solve, group 2 by ProTaper Universal retreatment instruments and group 3 by ProTaper Universal retreatment instruments along with RC solve was done. Retreatment was considered complete for all groups when no filling material was observed on the instruments. The retreatment time was recorded for each tooth. All specimens were grooved longitudinally in a buccolingual direction. The split halves were examined under a stereomicroscope and images were captured and analyzed. The remaining filling debris area ratios were considered for statistical analysis. Results: With ANOVA test, statistical analysis showed that there was statistically no significant difference regarding the amount of filling remnants between the groups (P < 0.05. Differences between the means of groups are statistically significant regarding the retreatment time. Conclusion: Irrespective of the technique used, all the specimens had some remnants on the root canal wall. ProTaper Universal retreatment system files alone proved to be faster than the other experimental groups.

  20. Effect of rotary or manual instrumentation, with or without a calcium hydroxide/1% chlorhexidine intracanal dressing, on the healing of experimentally induced chronic periapical lesions.

    Science.gov (United States)

    De Rossi, Andiara; Silva, Léa A B; Leonardo, Mario R; Rocha, Lenaldo B; Rossi, Marcos A

    2005-05-01

    To evaluate the healing of experimentally induced chronic periapical lesions in dogs at 30, 75, and 120 days after root canal instrumentation with rotary NiTi files or manual K-files, with or without a calcium hydroxide/1% chlorhexidine paste intracanal dressing. The second, third, and fourth mandibular premolars and the second and third maxillary premolars of 5 dogs (12 to 18 months of age, weighing 8 to 15 kg) were selected for treatment (a total of 82 root canals). After pulp removal, the root canals were left exposed to the oral cavity for 7 days to allow microbial contamination, after which the root canals were sealed with ZOE cement until periapical lesions were confirmed with radiography. Group I and II teeth were instrumented with manual K-files using the crown-down technique. In group III and IV teeth, NiTi rotary files were used. The apical delta was perforated by using #20 to #30 K-files at the length of the tooth, thus creating a standardized apical opening. The apical stop was enlarged to size 70, with 2.5% sodium hypochlorite irrigation at each file change. Teeth in groups II and IV were dressed with calcium hydroxide (Ca(OH) 2 )/1% chlorhexidine (CHX) paste for 15 days before root filling. Group I and III teeth did not receive an intracanal dressing. The access openings of the teeth were permanently restored with silver amalgam condensed on a glass ionomer cement base. Pairs of standardized periapical radiographs were taken at the beginning of the treatment (0 days) and at 30, 75, and 120 days after filling. There was no significant difference in the rate of radiographic healing of the periapical lesions between manual and rotary instrumentation. Radiographs taken at 120 days showed that the treatment with Ca(OH) 2 /1% CHX paste resulted in a significant reduction in mean size of the periapical lesions in comparison to single-session treatment. These findings were also true for histologic observations. The findings support the hypothesis that

  1. Structural characterisation and mechanical FE analysis of conventional and M-Wire Ni-Ti alloys used in endodontic rotary instruments.

    Science.gov (United States)

    Montalvão, Diogo; Alçada, Francisca Sena; Braz Fernandes, Francisco Manuel; de Vilaverde-Correia, Sancho

    2014-01-01

    The purpose of this study is to understand how the M-Wire alloy conditions the mechanical flexibility of endodontic rotary files at body temperature.Two different rotary instruments, a Profile GT 20/.06 and a Profile GT Series X 20/.06, were selected due to their geometrical similarity and their different constituent alloy. GT series X files are made from M-Wire, a Ni-Ti alloy allegedly having higher flexibility at body temperature. Both files were analysed by X-Ray Diffraction and Differential Scanning Calorimetry to investigate phase transformations and the effects of working temperature on these different alloys. Mechanical behaviour was assessed by means of static bending and torsional Finite Element simulations, taking into account the nonlinear superelastic behaviour of Ni-Ti materials. It was found that GT files present austenitic phase at body temperature, whereas GT series X present R-phase at temperatures under 40 °C with a potential for larger flexibility. For the same load conditions, simulations showed that the slight geometrical differences between the two files do not introduce great disagreement in the instruments' mechanical response. It was confirmed that M-Wire increases the instrument's flexibility, mainly due to the presence of R-phase at body temperature.

  2. Wall thickness measurements of tubes by Internal Rotary Inspection System (IRIS)- a comparative study with metallography

    International Nuclear Information System (INIS)

    Subramanian, C.V.; Joseph, A.; Ramesh, A.S.; Jayakumar, T.; Kalyanasundaram, P.; Baldev Raj

    1996-01-01

    Internal Rotary Inspection System (IRIS) is a relatively new ultrasonic system of heat exchanger/ steam condenser tubes and pipelines for measurement of wall thinning and pitting due to corrosion. The wall thickness measurements made during a scan around the circumference of the tube are displayed as a stationary rectilinear display of circumferential cross section (Bscan) of the tube. The paper describes the results obtained on tubes of various materials used in process industries having corrosion on inner and outer surfaces of the tube. (author)

  3. Cyclic Fatigue Testing of Three Different Rotary Nickel Titanium Endodontic Instruments in Simulated Curved Canals - An in Vitro Sem Analysis

    OpenAIRE

    Reddy Y., Pallavi; S., Kavita; Subbarao, C.V.

    2014-01-01

    Introduction: Instrument separation is a serious concern in endodontics. Stainless steel instruments usually deform before they separate whereas Nickel Titanium instruments do not show any sign of deformation.

  4. Dynamic Torsional and Cyclic Fracture Behavior of ProFile Rotary Instruments at Continuous or Reciprocating Rotation as Visualized with High-speed Digital Video Imaging.

    Science.gov (United States)

    Tokita, Daisuke; Ebihara, Arata; Miyara, Kana; Okiji, Takashi

    2017-08-01

    This study examined the dynamic fracture behavior of nickel-titanium rotary instruments in torsional or cyclic loading at continuous or reciprocating rotation by means of high-speed digital video imaging. The ProFile instruments (size 30, 0.06 taper; Dentsply Maillefer, Ballaigues, Switzerland) were categorized into 4 groups (n = 7 in each group) as follows: torsional/continuous (TC), torsional/reciprocating (TR), cyclic/continuous (CC), and cyclic/reciprocating (CR). Torsional loading was performed by rotating the instruments by holding the tip with a vise. For cyclic loading, a custom-made device with a 38° curvature was used. Dynamic fracture behavior was observed with a high-speed camera. The time to fracture was recorded, and the fractured surface was examined with scanning electron microscopy. The TC group initially exhibited necking of the file followed by the development of an initial crack line. The TR group demonstrated opening and closing of a crack according to its rotation in the cutting and noncutting directions, respectively. The CC group separated without any detectable signs of deformation. In the CR group, initial crack formation was recognized in 5 of 7 samples. The reciprocating rotation exhibited a longer time to fracture in both torsional and cyclic fatigue testing (P rotary instruments, as visualized with high-speed digital video imaging, varied between the different modes of rotation and different fatigue testing. Reciprocating rotation induced a slower crack propagation and conferred higher fatigue resistance than continuous rotation in both torsional and cyclic loads. Copyright © 2017 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  5. Comparative analysis of torsional and bending behavior through finite-element models of 5 Ni-Ti endodontic instruments.

    Science.gov (United States)

    Arbab-Chirani, Reza; Chevalier, Valérie; Arbab-Chirani, Shabnam; Calloch, Sylvain

    2011-01-01

    The objectives of this study were to compare numerically the bending and torsional mechanical behavior of 5 endodontic rotary Ni-Ti instruments with equivalent size and various designs for tapers, pitch, and cutting blades.First, the geometries of Hero (20/0.06), HeroShaper (20/0.06), ProFile (20/0.06), Mtwo (20/0.06), and ProTaper F1 were generated by finite element code. Then, the 2 most representative clinical loadings, i.e., bending and torsion, were studied with an ad hoc model for the superelasticity of Ni-Ti. Bending was generated by tip deflection and torsion by a constant twist-angle of the tip. Mechanical behavior of these 5 endodontic rotary Ni-Ti instruments could be evaluated and compared. Protaper F1 presented the greatest level of bending stress and torque. Hero and HeroShaper were more rigid than ProFile and Mtwo. This numerical comparison evaluated the effects of the geometrical parameters on the instrumental mechanical behavior. The 5 endodontic instruments, investigated in the present study, do not have the same bending and torsional mechanical behavior. Each clinician must be aware of these behavior differences so as to use the adequate file according to the clinical situation and to the manufacturer's recommendations. Copyright © 2011 Mosby, Inc. All rights reserved.

  6. Three-dimensional evaluation of effectiveness of hand and rotary instrumentation for retreatment of canals filled with different materials.

    Science.gov (United States)

    Hammad, Mohammad; Qualtrough, Alison; Silikas, Nick

    2008-11-01

    The aim of this study was to measure the remaining filling volume of different obturation materials from root-filled extracted teeth by using 2 removal techniques. Eighty single-rooted teeth were collected and decoronated, and the root canal was prepared by using the ProTaper nickel-titanium rotary files. The teeth were randomly allocated into 4 groups, and each group was obturated by using a different material. Group 1 was filled with gutta-percha and TubliSeal sealer, group 2 was filled with EndoRez points and EndoRez sealer, group 3 was filled with RealSeal points and RealSeal sealer, and Group 4 was filled with a gutta-percha point and GuttaFlow sealer. Teeth were scanned with a micro-computed tomography scan, and then root fillings were removed by using ProTaper retreatment files or hand K-files. Teeth were scanned again, and volume measurements were carried out with micro-computed tomography software. Statistical analysis showed significant differences between the 2 removal techniques for gutta-percha and for both techniques between gutta-percha and the other groups. The present study showed that all tested filling materials were not completely removed during retreatment by using hand or rotary files. Gutta-percha was more efficiently removed by using hand K-files.

  7. Root Canal Transportation and Centering Ability of Nickel-Titanium Rotary Instruments in Mandibular Premolars Assessed Using Cone-Beam Computed Tomography.

    Science.gov (United States)

    Mamede-Neto, Iussif; Borges, Alvaro Henrique; Guedes, Orlando Aguirre; de Oliveira, Durvalino; Pedro, Fábio Luis Miranda; Estrela, Carlos

    2017-01-01

    The aim of this study was to evaluate, using cone-beam computed tomography (CBCT), transportation and centralization of different nickel-titanium (NiTi) rotary instruments. One hundred and twenty eight mandibular premolars were selected and instrumented using the following brands of NiTi files: WaveOne, WaveOne Gold, Reciproc, ProTaper Next, ProTaper Gold, Mtwo, BioRaCe and RaCe. CBCT imaging was performed before and after root canal preparation to obtain measurements of mesial and distal dentin walls and calculations of root canal transportation and centralization. A normal distribution of data was confirmed by the Kolmogorov-Smirnov and Levene tests, and results were assessed using the Kruskal-Wallis test. Statistical significance was set at 5%. ProTaper Gold produced the lowest canal transportation values, and RaCe, the highest. ProTaper Gold files also showed the highest values for centering ability, whereas BioRaCe showed the lowest. No significant differences were found across the different instruments in terms of canal transportation and centering ability (P > 0.05). Based on the methodology employed, all instruments used for root canal preparation of mandibular premolars performed similarly with regard to canal transportation and centering ability.

  8. Radiological evaluation of the morphological changes of root canals shaped with ProTaper for hand use and the ProTaper and RaCe rotary instruments.

    Science.gov (United States)

    Aguiar, Carlos M; Câmara, Andréa C

    2008-12-01

    This study evaluated, by means of the radiography examination, the occurrence of deviations in the apical third of root canals shaped with hand and rotary instruments. Sixty mandibular human molars were divided into three groups. The root canals in group 1 were instrumented with ProTaper (Dentsply/Maillefer, Ballaigues, Switzerland) for hand use, group 2 with ProTaper and group 3 with RaCe. The images obtained by double superimposition of the pre- and postoperative radiographs were evaluated by two endodontists with the aid of a magnifier-viewer and a fivefold magnifier. Statistical analysis was performed using the Fisher-Freeman-Halton. The instrumentation using the ProTaper for hand use showed 25% of the canals with a deviation in the apical third, as did the ProTaper, while the corresponding figure for the RaCe (FKG Dentaire, La-Chaux-de-Fonds, Switzerland) was 20%, but these results were not statistically significant. There was no correlation between the occurrence of deviations in the apical third and the systems used.

  9. Comparative analysis of efficacy and cleaning ability of hand and rotary devices for gutta-percha removal in root canal retreatment: an in vitro study.

    Science.gov (United States)

    Reddy, Narender; Admala, Shilpa Reddy; Dinapadu, Sainath; Pasari, Srikanth; Reddy, Manoranjan P; Rao, M S Rama

    2013-07-01

    To evaluate the efficacy and cleaning ability of Hedstrom files, and ProTaper retreatment instruments in removing gutta-percha from root canals with and without xylene as solvent. Sixty extracted single rooted human teeth were selected and decoronated, straight access established working length determined 1 mm short of canal, chemomechanical preparation done and obturated with guttapercha and AH plus sealer. Samples were stored for 1 week in humidifier divided into four groups of 15 teeth each. • Group I: Hedstrom files without xylene. • Group II: Hedstrom files with xylene. • Group III: ProTaper retreatment instruments without xylene. • Group IV: ProTaper retreatment instruments with xylene. and the following criteria were assessed - Time taken for initial plunge of instrument into guttapercha. - Time taken for complete removal of gutta-percha to reach working length - Ability of H files and ProTaper retreatment files with/ without xylene to remove gutta-percha in coronal, middle and apical 1/3 of canal. The teeth were grooved in labiolingual cross section, observed under a steromicroscope and scored according to gutta-percha debris left in the canal. Results were evaluated using ANOVA test and multiple comparisons done using Scheffe test. The least time to reach working length was found with group IV followed by groups III, II and group I respectively. Also the fastest way to remove maximum gutta-percha was group IV followed by groups III, II, and I respectively with a statistically significant difference among all groups. Apical 1/3 has more amount of remaining gutta-percha debris than middle and coronal 1/3 in all groups. The amount of gutta-percha debris in apical 1/3 was least in group IV followed by groups III, II and I respectively. The better performance of ProTaper rotary instruments has been attributed to their special flute design which tends to pull gutta-percha coronally directing it toward orifice. Also the movements of engine driven

  10. In Vivo and In Vitro Effectiveness of Rotary Nickel-Titanium vs Manual Stainless Steel Instruments for Root Canal Therapy: Systematic Review and Meta-analysis.

    Science.gov (United States)

    Del Fabbro, Massimo; Afrashtehfar, Kelvin Ian; Corbella, Stefano; El-Kabbaney, Ahmed; Perondi, Isabella; Taschieri, Silvio

    2018-03-01

    This systematic review evaluated the effectiveness of nickel-titanium (NiTi) rotary files compared to stainless-steel (SST) hand files. An electronic search was performed on Medline, EMBASE, CENTRAL and Scopus databases up to February 2016. An additional hand searching was performed in 13 journals. The studies were classified according to study type and the outcome variables. Two reviewers independently applied eligibility criteria, extracted data, and three reviewers independently assessed the quality of the evidence of each included study according to The Cochrane Collaboration's procedures. A meta-analysis was performed whenever it was possible. The electronic and hand search strategies yielded 1155 references of studies after removal of duplicates. Four clinical studies (two prospective and two retrospective studies) and 18 in vitro studies (on extracted teeth) were included for the qualitative synthesis after full-text evaluation of the eligible studies. The overall level of methodological quality of the studies included can be considered inadequate. Only one clinical study was judged at low risk of bias, whereas most non-clinical studies had a low risk of bias. Three meta-analyses, based on a very limited number of studies, could be performed. Each meta-analysis contained two studies. Of these, one meta-analysis was based on clinical studies. The results of this systematic review suggested that NiTi rotary instruments were associated with lower canal transportation and apical extrusion when compared to SST hand files, whereas both groups had similar outcomes in terms of success of therapy, amount of residual bacteria, and cleansing ability after treatment. However, due to the limited evidence available, these results should be interpreted with caution. Consequently, more randomized control trials using standardized protocols are needed in order to provide more solid recommendations. Copyright © 2017 Elsevier Inc. All rights reserved.

  11. Evaluation of surface preparation and maintenance of canal curvature following instrumentation with hand 'K' file and three different Ni-Ti rotary systems: A radiographic and SEM study.

    Science.gov (United States)

    Bhatti, Namrata; Sroa, Renu; Sikri, Vimal K

    2010-04-01

    To determine the shaping ability and cleaning efficiency of hand K-flexofiles, ProTaper, LightSpeed and Mtwo instruments during the preparation of curved root canals in extracted human teeth. A total of 120 root canals of mandibular and maxillary molars with curvature more than 20° were divided into four groups of 30 each. In group A, canals were prepared using hand K-flexofiles following the crown down technique. In group B LightSpeed, in group C ProTaper, and in group D Mtwo rotary instruments were used to prepare the root canals. Using pre- and post-instrumentation radiographs, straightening of the canal curvature was determined with Corel Draw 9.0 software tools. The amount of debris and smear layer were quantified at three different areas (coronal, middle, and apical thirds) of root canal using SEM. The collected data were analyzed statistically using Student's paired 't' test. The mean change in curvature for hand K-files was 7.71°, for ProTaper files 6.03°, for Mtwo 5.43°, and for LightSpeed instruments were found to be 4.57°. The percentage change in the curvature for all the four groups was statistically highly significant (PProTaper (65.48%) followed by Mtwo (66.22%), LightSpeed (71.67%) and the maximum with hand K-files (74.16%). However, the difference in mean leftover debris between ProTaper and Mtwo was not significant. ProTaper and Mtwo resulted in good cleaning, and LightSpeed maintained the original canal curvature better than the ProTaper, Mtwo, or Hand K-files.

  12. Rotary capacitor

    CERN Multimedia

    CERN PhotoLab

    1971-01-01

    The rotating wheel of the rotary capacitor representing the most critical part of the new radio-frequency system of the synchro-cyclotron. The three rows of teeth on the circumference of the wheel pass between four rows of stator blades with a minimum clearance of 1 mm at a velocity of 1700 rev/min.

  13. Falsification Testing of Instrumental Variables Methods for Comparative Effectiveness Research.

    Science.gov (United States)

    Pizer, Steven D

    2016-04-01

    To demonstrate how falsification tests can be used to evaluate instrumental variables methods applicable to a wide variety of comparative effectiveness research questions. Brief conceptual review of instrumental variables and falsification testing principles and techniques accompanied by an empirical application. Sample STATA code related to the empirical application is provided in the Appendix. Comparative long-term risks of sulfonylureas and thiazolidinediones for management of type 2 diabetes. Outcomes include mortality and hospitalization for an ambulatory care-sensitive condition. Prescribing pattern variations are used as instrumental variables. Falsification testing is an easily computed and powerful way to evaluate the validity of the key assumption underlying instrumental variables analysis. If falsification tests are used, instrumental variables techniques can help answer a multitude of important clinical questions. © Health Research and Educational Trust.

  14. Comparing surgical trays with redundant instruments with trays with reduced instruments: a cost analysis.

    Science.gov (United States)

    John-Baptiste, A; Sowerby, L J; Chin, C J; Martin, J; Rotenberg, B W

    2016-01-01

    When prearranged standard surgical trays contain instruments that are repeatedly unused, the redundancy can result in unnecessary health care costs. Our objective was to estimate potential savings by performing an economic evaluation comparing the cost of surgical trays with redundant instruments with surgical trays with reduced instruments ("reduced trays"). We performed a cost-analysis from the hospital perspective over a 1-year period. Using a mathematical model, we compared the direct costs of trays containing redundant instruments to reduced trays for 5 otolaryngology procedures. We incorporated data from several sources including local hospital data on surgical volume, the number of instruments on redundant and reduced trays, wages of personnel and time required to pack instruments. From the literature, we incorporated instrument depreciation costs and the time required to decontaminate an instrument. We performed 1-way sensitivity analyses on all variables, including surgical volume. Costs were estimated in 2013 Canadian dollars. The cost of redundant trays was $21 806 and the cost of reduced trays was $8803, for a 1-year cost saving of $13 003. In sensitivity analyses, cost savings ranged from $3262 to $21 395, based on the surgical volume at the institution. Variation in surgical volume resulted in a wider range of estimates, with a minimum of $3253 for low-volume to a maximum of $52 012 for high-volume institutions. Our study suggests moderate savings may be achieved by reducing surgical tray redundancy and, if applied to other surgical specialties, may result in savings to Canadian health care systems.

  15. Evaluation of apical canal shapes produced sequentially during instrumentation with stainless steel hand and Ni-Ti rotary instruments using Micro-computed tomography

    Directory of Open Access Journals (Sweden)

    Woo-Jin Lee

    2011-05-01

    Full Text Available Objectives The purpose of this study was to determine the optimal master apical file size with minimal transportation and optimal efficiency in removing infected dentin. We evaluated the transportation of the canal center and the change in untouched areas after sequential preparation with a #25 to #40 file using 3 different instruments: stainless steel K-type (SS K-file hand file, ProFile and LightSpeed using microcomputed tomography (MCT. Materials and Methods Thirty extracted human mandibular molars with separated orifices and apical foramens on mesial canals were used. Teeth were randomly divided into three groups: SS K-file, Profile, LightSpeed and the root canals were instrumented using corresponding instruments from #20 to #40. All teeth were scanned with MCT before and after instrumentation. Cross section images were used to evaluate canal transportation and untouched area at 1- , 2- , 3- , and 5- mm level from the apex. Data were statistically analyzed according to' repeated nested design'and Mann-Whitney test (p = 0.05. Results In SS K-file group, canal transportation was significantly increased over #30 instrument. In the ProFile group, canal transportation was significantly increased after preparation with the #40 instrument at the 1- and 2- mm levels. LightSpeed group showed better centering ability than ProFile group after preparation with the #40 instrument at the 1 and 2 mm levels. Conclusions SS K-file, Profile, and LightSpeed showed differences in the degree of apical transportation depending on the size of the master apical file.

  16. Evaluation of the efficacy of rotary vs. hand files in root canal preparation of primary teeth in vitro using CBCT.

    Science.gov (United States)

    Musale, P K; Mujawar, S A V

    2014-04-01

    This in vitro study aimed to evaluate the efficacy of rotary ProFile, ProTaper, Hero Shaper and K-files in shaping ability, cleaning efficacy, preparation time and instrument distortion in primary molars. Sixty extracted primary mandibular second molars were divided into four equal groups: Group I K-file, Group II ProFile, Group III ProTaper file and Group IV Hero Shaper file. The shaping ability was determined by comparing pre- and post-instrumentation CBCT scans and data analysed with SPSS program using the Chi-square test. Cleaning efficacy was evaluated by the degree of India ink removal from the canal walls under stereomicroscopy. Instrumentation times were calculated for each tooth and instrument distortion was visually checked and duly noted. The cleaning efficacy and instrumentation time were determined using ANOVA with Tukey's correction. Instrument distortion was analysed using Chi-square test. The canal taper was significantly more conical for rotary files as compared to K-files with Chi-square test (p < 0.05). Cleaning efficacy of rotary files with average scores (Groups II- 0.68, III- 0.48 and IV- 0.58) was significantly better than K-files (Group I- 0.93) (p < 0.05). Mean instrumentation time with K-file (20.7 min) was significantly higher than rotary files (Groups II 8.9, III 5.6, and IV 8.1 min) (p < 0.05). Instrument distortion was observed in Group I (4.3%), while none of the rotary files were distorted. Rotary files prepared more conical canals in primary teeth than manual instruments. Reduced preparation time with rotary files enhances patient cooperation especially in young children.

  17. Rotary endodontics in primary teeth - A review.

    Science.gov (United States)

    George, Sageena; Anandaraj, S; Issac, Jyoti S; John, Sheen A; Harris, Anoop

    2016-01-01

    Endodontic treatment in primary teeth can be challenging and time consuming, especially during canal preparation, which is considered one of the most important steps in root canal therapy. The conventional instrumentation technique for primary teeth remains the "gold-standard" over hand instrumentation, which makes procedures much more time consuming and adversely affects both clinicians and patients. Recently nickel-titanium (Ni-Ti) rotary files have been developed for use in pediatric endodontics. Using rotary instruments for primary tooth pulpectomies is cost effective and results in fills that are consistently uniform and predictable. This article reviews the use of nickel-titanium rotary files as root canal instrumentation in primary teeth. The pulpectomy technique is described here according to different authors and the advantages and disadvantages of using rotary files are discussed.

  18. Mechanical behavior of M-Wire and conventional NiTi wire used to manufacture rotary endodontic instruments.

    Science.gov (United States)

    Pereira, Erika S J; Gomes, Renata O; Leroy, Agnès M F; Singh, Rupinderpal; Peters, Ove A; Bahia, Maria G A; Buono, Vicente T L

    2013-12-01

    Comparison of physical and mechanical properties of one conventional and a new NiTi wire, which had received an additional thermomechanical treatment. Specimens of both conventional (NiTi) and the new type of wire, called M-Wire (MW), were subjected to tensile and three-point bending tests, Vickers microhardness measurements, and to rotating-bending fatigue tests at a strain-controlled level of 6%. Fracture surfaces were observed by scanning electron microscopy and the non-deformed microstructures by transmission electron microscopy. The thermomechanical treatment applied to produce the M-Wire apparently increased the tensile strength and Vickers microhardness of the material, but its apparent Young modulus was smaller than that of conventionally treated NiTi. The three-point bending tests showed a higher flexibility for MW which also exhibited a significantly higher number of cycles to failure. M-Wire presented mechanical properties that can render endodontic instruments more flexible and fatigue resistant than those made with conventionally processed NiTi wires. Copyright © 2013 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  19. Incidence of apical crack initiation and propagation during the removal of root canal filling material with ProTaper and Mtwo rotary nickel-titanium retreatment instruments and hand files.

    Science.gov (United States)

    Topçuoğlu, Hüseyin Sinan; Düzgün, Salih; Kesim, Bertan; Tuncay, Oznur

    2014-07-01

    The aim of this study was to determine the incidence of crack initiation and propagation in apical root dentin after retreatment procedures performed by using 2 rotary retreatment systems and hand files with additional instrumentation. Eighty extracted mandibular premolars with single canals were selected. One millimeter from the apex of each tooth was ground perpendicular to the long axis of the tooth, and the apical surface was polished. Twenty teeth served as the control group, and no preparation was performed. The remaining 60 teeth were prepared to size 35 with rotary files and filled with gutta-percha and AH Plus sealer. Specimens were then divided into 3 groups (n = 20), and retreatment procedures were performed with the following devices and techniques: ProTaper Universal retreatment files, Mtwo retreatment files, and hand files. After retreatment, the additional instrumentation was performed by using size 40 ProTaper, Mtwo, and hand files. Digital images of the apical root surface were recorded before preparation, after instrumentation, after filling, after retreatment, and after additional instrumentation. The images were then inspected for the presence of any new apical cracks and propagation. Data were analyzed with the logistic regression and Fisher exact tests. All experimental groups caused crack initiation and propagation after use of retreatment instruments. The ProTaper and Mtwo retreatment groups caused greater crack initiation and propagation than the hand instrument group (P ProTaper and Mtwo instruments after the use of retreatment instruments caused crack initiation and propagation, whereas hand files caused neither crack initiation nor propagation (P < .05). This study showed that retreatment procedures and additional instrumentation after the use of retreatment files may cause crack initiation and propagation in apical dentin. Copyright © 2014 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  20. Instrumental variable methods in comparative safety and effectiveness research.

    Science.gov (United States)

    Brookhart, M Alan; Rassen, Jeremy A; Schneeweiss, Sebastian

    2010-06-01

    Instrumental variable (IV) methods have been proposed as a potential approach to the common problem of uncontrolled confounding in comparative studies of medical interventions, but IV methods are unfamiliar to many researchers. The goal of this article is to provide a non-technical, practical introduction to IV methods for comparative safety and effectiveness research. We outline the principles and basic assumptions necessary for valid IV estimation, discuss how to interpret the results of an IV study, provide a review of instruments that have been used in comparative effectiveness research, and suggest some minimal reporting standards for an IV analysis. Finally, we offer our perspective of the role of IV estimation vis-à-vis more traditional approaches based on statistical modeling of the exposure or outcome. We anticipate that IV methods will be often underpowered for drug safety studies of very rare outcomes, but may be potentially useful in studies of intended effects where uncontrolled confounding may be substantial.

  1. Instrumental variable methods in comparative safety and effectiveness research†

    Science.gov (United States)

    Brookhart, M. Alan; Rassen, Jeremy A.; Schneeweiss, Sebastian

    2010-01-01

    Summary Instrumental variable (IV) methods have been proposed as a potential approach to the common problem of uncontrolled confounding in comparative studies of medical interventions, but IV methods are unfamiliar to many researchers. The goal of this article is to provide a non-technical, practical introduction to IV methods for comparative safety and effectiveness research. We outline the principles and basic assumptions necessary for valid IV estimation, discuss how to interpret the results of an IV study, provide a review of instruments that have been used in comparative effectiveness research, and suggest some minimal reporting standards for an IV analysis. Finally, we offer our perspective of the role of IV estimation vis-à-vis more traditional approaches based on statistical modeling of the exposure or outcome. We anticipate that IV methods will be often underpowered for drug safety studies of very rare outcomes, but may be potentially useful in studies of intended effects where uncontrolled confounding may be substantial. PMID:20354968

  2. SEM evaluation of the morphological changes in hard dental tissues prepared by Er: YAG laser and rotary instruments

    Directory of Open Access Journals (Sweden)

    Tomov Georgi

    2010-09-01

    Full Text Available Effective ablation of dental hard tissues by means of the erbium:yttrium-aluminum garnet (Er: YAG laser has been reported recently, and its application to caries removal and cavity preparation has been expected. However, few studies have investigated the morphological changes in hard dental tissues after Er: YAG laser caries treatment. In the present study the morphological changes in hard dental tissues after Er: YAG laser caries ablation in vitro was compared with that of conventional mechanical treatment. Thirty extracted human teeth with caries were used. Ten tooth was treated with the Er: YAG laser, and the other was treated with a conventional steel and diamond burs. Laser treatment was performed by means of a non-contact irradiation modes with cooling water spray, with a new Er: YAG laser (LiteTouch. Conventional bur treatment was conducted by means of a low-speed micromotor and air turbine with water cooling. Scanning electron microscope (SEM observations were performed for each treatment. The Er: YAG laser ablated carious dentin effectively with minimal thermal damage to the surrounding intact dentin, and removed infected and softened carious dentin to the same degree as the burtreatment. In addition, a lower degree of vibration was noted with the Er: YAG laser treatment. The SEM examination revealed characteristic micro-irregularities of the lased dentin and enamel surfaces with potential benefits for adhesive restorations. Our results show that the Er: YAG laser is promising as a new technical modality for caries treatment

  3. An Improved Rotary Interpolation Based on FPGA

    Directory of Open Access Journals (Sweden)

    Mingyu Gao

    2014-08-01

    Full Text Available This paper presents an improved rotary interpolation algorithm, which consists of a standard curve interpolation module and a rotary process module. Compared to the conventional rotary interpolation algorithms, the proposed rotary interpolation algorithm is simpler and more efficient. The proposed algorithm was realized on a FPGA with Verilog HDL language, and simulated by the ModelSim software, and finally verified on a two-axis CNC lathe, which uses rotary ellipse and rotary parabolic as an example. According to the theoretical analysis and practical process validation, the algorithm has the following advantages: firstly, less arithmetic items is conducive for interpolation operation; and secondly the computing time is only two clock cycles of the FPGA. Simulations and actual tests have proved that the high accuracy and efficiency of the algorithm, which shows that it is highly suited for real-time applications.

  4. Effect of piezoelectric instruments on healing propensity of alveolar sockets following mandibular third molar extraction

    OpenAIRE

    Shang-Jye Tsai; Yen-Liang Chen; Hao-Hueng Chang; Yow-Chyun Shyu; Chun-Pin Lin

    2012-01-01

    Background/purpose: The purpose of this study was to investigate whether the use of piezoelectric instruments affected the healing propensity of alveolar sockets after mandibular third molar extraction, compared with conventional rotary instruments. Materials and methods: Thirty patients with impacted bilateral symmetrical mandibular third molars participated in this investigation. We conducted a randomized, crossover study using conventional rotary instruments for extraction on one side a...

  5. Comparison of apical debris extrusion using a conventional and two rotary techniques.

    Science.gov (United States)

    Adl, Alireza; Sahebi, Safoora; Moazami, Fariborz; Niknam, Mahnaz

    2009-01-01

    Preparation techniques and instruments produce and push debris out of canals. This can induce inflammation within the periapical area. Therefore, instrumentation that causes less extrusion of debris is more desirable. The purpose of this in vitro study was to evaluate the quantity of debris extruded from the apical foramen during root canal preparation by using one hand, and two rotary instrumentation techniques. Three different groups each with 12 mesiobuccal roots of human maxillary first molar were instrumented using either step-back technique with hand instruments, FlexMaster or Mtwo rotary system. Debris extruded from the apical foramen during canal preparation was collected. The mean dry weights of debris were compared using one-way ANOVA. Step-back group had a significantly greater mean weight of debris compared to the other two groups (Pengine driven techniques were associated with less apical debris extrusion. [Iranian Endodontic Journal 2009;4(4):135-8].

  6. A smart rotary technique versus conventional pulpectomy for primary teeth: A randomized controlled clinical study.

    Science.gov (United States)

    Mokhtari, Negar; Shirazi, Alireza-Sarraf; Ebrahimi, Masoumeh

    2017-11-01

    Techniques with adequate accuracy of working length determination along with shorter duration of treatment in pulpectomy procedure seems to be essential in pediatric dentistry. The aim of the present study was to evaluate the accuracy of root canal length measurement with Root ZX II apex locator and rotary system in pulpectomy of primary teeth. In this randomized control clinical trial complete pulpectomy was performed on 80 mandibular primary molars in 80, 4-6-year-old children. The study population was randomly divided into case and control groups. In control group conventional pulpectomy was performed and in the case group working length was determined by electronic apex locator Root ZXII and instrumented with Mtwo rotary files. Statistical evaluation was performed using Mann-Whitney and Chi-Square tests ( P <0.05). There were no significant differences between electronic apex locator Root ZXII and conventional method in accuracy of root canal length determination. However significantly less time was needed for instrumenting with rotary files ( P =0.000). Considering the comparable results in accuracy of root canal length determination and the considerably shorter instrumentation time in Root ZXII apex locator and rotary system, it may be suggested for pulpectomy in primary molar teeth. Key words: Rotary technique, conventional technique, pulpectomy, primary teeth.

  7. Shaping abilities of two different engine-driven rotary nickel titanium systems or stainless steel balanced-force technique in mandibular molars.

    Science.gov (United States)

    Matwychuk, Michael J; Bowles, Walter R; McClanahan, Scott B; Hodges, Jim S; Pesun, Igor J

    2007-07-01

    The purpose of this study was to compare apical transportation, working-length changes, and instrumentation time by using nickel-titanium (Ni-Ti) rotary file systems (crown-down method) or stainless steel hand files (balanced-force technique) in mesiobuccal canals of extracted mandibular molars. The curvature of each canal was determined and teeth placed into three equivalent groups. Group 1 was instrumented with Sequence (Brasseler USA, Savannah, GA) rotary files, group 2 with Liberator (Miltex Inc, York, PA) rotary files, and group 3 with Flex-R (Union Broach, New York, NY) files. Pre- and postoperative radiographs were superimposed to measure loss of working length and apical transportation as shown by changes in radius of curvature and the long-axis canal angle. Sequence rotary files, Liberator rotary files, and Flex-R hand files had similar effects on apical canal transportation and changes in working length, with no significant differences detected among the 3 groups. Hand instrumentation times were longer than with either Ni-Ti rotary group, whereas the rotary NiTi groups had a higher incidence of fracture.

  8. Influence of NiTi alloy on the root canal shaping capabilities of the ProTaper Universal and ProTaper Gold rotary instrument systems

    Directory of Open Access Journals (Sweden)

    Jussaro Alves DUQUE

    Full Text Available Abstract Objective This study aimed to evaluate the influence of the NiTi wire in Conventional NiTi (ProTaper Universal PTU and Controlled Memory NiTi (ProTaper Gold PTG instrument systems on the quality of root canal preparation. Material and Methods Twelve mandibular molars with separate mesial canals were scanned using a high-definition microcomputed tomography system. The PTU and PTG instruments were used to shape twelve mesial canals each. The canals were scanned after preparation with F2 and F3 instruments of the PTU and PTG systems. The analyzed parameters included the remaining dentin thickness at the apical and cervical levels, root canal volume and untouched canal walls. Data was analyzed for statistical significance by the Friedman and Dunn’s tests. For the comparison of data between groups, the Mann-Whitney test was used. Results In the pre-operative analysis, there were no statistically significant differences between the groups in terms of the area and volume of root canals (P>.05. There was also no statistically significant difference between the systems with respect to root canal volume after use of the F2 and F3 instruments. There was no statistical difference in the dentin thickness at the first apical level between, before and after instrumentation for both systems. At the 3 cervical levels, the PTG maintained centralization of the preparation on the transition between the F2 and F3 instruments, which did not occur with the PTU. Conclusion The Conventional NiTi (PTU and Controlled Memory NiTi (PTG instruments displayed comparable capabilities for shaping the straight mesial root canals of mandibular molars, although the PTG was better than the PTU at maintaining the centralization of the shape in the cervical portion.

  9. Influence of NiTi alloy on the root canal shaping capabilities of the ProTaper Universal and ProTaper Gold rotary instrument systems

    Science.gov (United States)

    DUQUE, Jussaro Alves; VIVAN, Rodrigo Ricci; CAVENAGO, Bruno Cavalini; AMOROSO-SILVA, Pablo Andrés; BERNARDES, Ricardo Affonso; de VASCONCELOS, Bruno Carvalho; DUARTE, Marco Antonio Hungaro

    2017-01-01

    Abstract Objective This study aimed to evaluate the influence of the NiTi wire in Conventional NiTi (ProTaper Universal PTU) and Controlled Memory NiTi (ProTaper Gold PTG) instrument systems on the quality of root canal preparation. Material and Methods Twelve mandibular molars with separate mesial canals were scanned using a high-definition microcomputed tomography system. The PTU and PTG instruments were used to shape twelve mesial canals each. The canals were scanned after preparation with F2 and F3 instruments of the PTU and PTG systems. The analyzed parameters included the remaining dentin thickness at the apical and cervical levels, root canal volume and untouched canal walls. Data was analyzed for statistical significance by the Friedman and Dunn’s tests. For the comparison of data between groups, the Mann-Whitney test was used. Results In the pre-operative analysis, there were no statistically significant differences between the groups in terms of the area and volume of root canals (P>.05). There was also no statistically significant difference between the systems with respect to root canal volume after use of the F2 and F3 instruments. There was no statistical difference in the dentin thickness at the first apical level between, before and after instrumentation for both systems. At the 3 cervical levels, the PTG maintained centralization of the preparation on the transition between the F2 and F3 instruments, which did not occur with the PTU. Conclusion The Conventional NiTi (PTU) and Controlled Memory NiTi (PTG) instruments displayed comparable capabilities for shaping the straight mesial root canals of mandibular molars, although the PTG was better than the PTU at maintaining the centralization of the shape in the cervical portion. PMID:28198973

  10. Satisfaction of undergraduate students at University of Jordan after root canal treatment of posterior teeth using rotary or hand preparation.

    Science.gov (United States)

    Abu-Tahun, Ibrahim; El-Ma'aita, Ahmad; Khraisat, Ameen

    2016-08-01

    The aim of this study was to report the satisfaction of fifth year undergraduate students on the clinical use of rotary endodontic preparation compared with stainless steel standard technique and to evaluate the impact of rotary nickel-titanium instruments on undergraduate teaching. This study was carried out by the fifth year undergraduate students attending peer review sessions as a part of their training program using a questionnaire to assess their satisfaction with these two techniques. The overall results indicated a statistically significant satisfaction of the undergraduate students with the use of the nickel-titanium system (P ProTaper rotary files and the need for undergraduate teaching of rotary nickel-titanium systems in Jordan. © 2015 Australian Society of Endodontology Inc.

  11. Comparison of the mechanical properties of rotary instruments made of conventional nickel-titanium wire, M-wire, or nickel-titanium alloy in R-phase.

    Science.gov (United States)

    Lopes, Hélio P; Gambarra-Soares, Thaiane; Elias, Carlos N; Siqueira, José F; Inojosa, Inês F J; Lopes, Weber S P; Vieira, Victor T L

    2013-04-01

    This study compared the mechanical properties of endodontic instruments made of conventional nickel-titanium (NiTi) wire (K(3) and Revo-S SU), M-Wire (ProFile Vortex), or NiTi alloy in R-phase (K(3)XF). The test instruments were subjected to mechanical tests to evaluate resistance to bending (flexibility), cyclic fatigue, and torsional load in clockwise rotation. Data were statistically evaluated by the analysis of variance test and the Student-Newman-Keuls test for multiple comparisons. In the bending resistance test, flexibility decreased in the following order: K(3)XF > Revo-S SU > ProFile Vortex > K(3). The ranking in the fatigue resistance test was the following: K(3)XF > K(3) > ProFile Vortex > Revo-S SU. In the torsional assay, the angular deflection at failure decreased in the following order: K(3)XF > Revo-S SU > K(3) > ProFile Vortex. For the maximum torque values, the ranking was K(3) > K(3)XF > ProFile Vortex > Revo-S SU. The results showed that the K(3)XF instrument, which is made of NiTi alloy in R-phase, had the overall best performance in terms of flexibility, angular deflection at failure, and cyclic fatigue resistance. In addition to the alloy from which the instrument is manufactured, the design and dimensions are important determinants of the mechanical performance of endodontic instruments. Copyright © 2013 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  12. HyFlex EDM: superficial features, metallurgical analysis and fatigue resistance of innovative electro discharge machined NiTi rotary instruments.

    Science.gov (United States)

    Pirani, C; Iacono, F; Generali, L; Sassatelli, P; Nucci, C; Lusvarghi, L; Gandolfi, M G; Prati, C

    2016-05-01

    To evaluate the surface and microstructural alterations of new and used HyFlex EDM prototypes and to test their fatigue resistance. Fifteen HyFlex EDM prototypes were used for in vitro instrumentation of severely curved root canals. Surface and microstructural characteristics of new and used files were compared by ESEM analysis equipped with energy dispersive X-ray spectrophotometry (EDS) and optical metallographic imaging. Usage-induced degradation was assessed. Thirty additional HyFlex EDM prototypes and 20 standard manufactured HyFlex CM files were subjected to cyclic fatigue tests. Time to fracture was recorded, and results were validated using the Kruskal-Wallis test (α-level 0.05). Fatigued files were analysed by ESEM for fractographic evaluation. Surface and microstructural characterization of EDM prototypes revealed the typical spark-machined surface of a NiTi EDM alloy. No fractures were registered during root canal instrumentation. No evident surface alterations and minor degradation were observed between new and used instruments. The metallographic analysis of new and used files disclosed a homogeneous structure, mostly composed of lenticular martensite grains, and some residual austenite. The cyclic fatigue test showed an increase of fatigue resistance up to 700% on the EDM compared to CM files. Spark-machined peculiar surface is the main feature of HyFlex EDM. Low degradation was observed after multiple canal instrumentations. Prototypes exhibited surprising high values of cyclic fatigue resistance and a safe in vitro use in severely curved canals. © 2015 International Endodontic Journal. Published by John Wiley & Sons Ltd.

  13. Effectiveness of ProTaper Universal retreatment instruments used with rotary or reciprocating adaptive motion in the removal of root canal filling material.

    Science.gov (United States)

    Capar, I D; Arslan, H; Ertas, H; Gök, T; Saygılı, G

    2015-01-01

    To compare the effectiveness of ProTaper Universal retreatment instruments with continuous rotation and adaptive motion (AM; a modified reciprocating motion that combines rotational and reciprocating motion) in the removal of filling material. Mesiobuccal root canals in 36 mandibular first molars were instrumented up to size F2 with the ProTaper Universal instrument (Dentsply Maillefer, Ballaigues, Switzerland) and filled using sealer and ProTaper Universal F2 gutta-percha cones. Gutta-percha was then down-packed and the root canal backfilled using the extruder hand-piece of the Elements Obturation System (SybronEndo, Orange, CA, USA). The teeth were assigned to two groups (n = 18), and removal of the root fillings was performed using one of the following techniques: group 1) ProTaper Universal retreatment files used with rotational motion (RM) and group 2) ProTaper Universal retreatment files used with adaptive motion (AM) (600° clockwise/0° counter-clockwise to 370° clockwise/50° counter-clockwise). The teeth were sectioned, and both halves were analysed at 8 × magnification. The percentage of remaining filling material was recorded. The data were analysed statistically using the Student's t-test at a 95% confidence level (P ProTaper Universal retreatment files with adaptive motion removed more filling materials from root canals than the rotational movement. © 2014 International Endodontic Journal. Published by John Wiley & Sons Ltd.

  14. Glass: Rotary Electric Glass Furnace

    Energy Technology Data Exchange (ETDEWEB)

    Recca, L.

    1999-01-29

    Compared to conventional gas-fired furnaces, the new rotary electric furnace will increase energy efficiency while significantly reducing air emissions, product turnaround time, and labor costs. As this informative new fact sheet explains, the thousand different types of glass optical blanks produced for the photonics industry are used for lasers, telescopes, cameras, lights, and many other products.

  15. Apical extrusion of debris during the preparation of oval root canals: a comparative study between a full-sequence SAF system and a rotary file system supplemented by XP-endo finisher file.

    Science.gov (United States)

    Kfir, Anda; Moza-Levi, Rotem; Herteanu, Moran; Weissman, Amir; Wigler, Ronald

    2018-03-01

    The purpose of this study was to assess the amount of apically extruded debris during the preparation of oval canals with either a rotary file system supplemented by the XP-endo Finisher file or a full-sequence self-adjusting file (SAF) system. Sixty mandibular incisors were randomly assigned to two groups: group A: stage 1-glide path preparation with Pre-SAF instruments. Stage 2-cleaning and shaping with SAF. Group B: stage 1-glide path preparation with ProGlider file. Stage 2-cleaning and shaping with ProTaper Next system. Stage 3-Final cleaning with XP-endo Finisher file. The debris extruded during each of the stages was collected, and the debris weights were compared between the groups and between the stages within the groups using t tests with a significance level set at P file followed by XP-endo Finisher file extruded significantly more debris than a full-sequence SAF system. Each stage, in either procedure, had its own contribution to the extrusion of debris. Final preparation with XP-endo Finisher file contributes to the total amount of extruded debris, but the clinical relevance of the relative difference in the amount of apically extruded debris remains unclear.

  16. Comparative evaluation of cyclic fatigue resistance of D-RaCe and ProTaper retreatment instruments in curved artificial canals.

    Science.gov (United States)

    Topçuoğlu, H S; Topçuoğlu, G; Aktı, A

    2016-06-01

    To compare the cyclic fatigue resistance of D-RaCe and ProTaper rotary nickel-titanium (NiTi) retreatment files when used in curved artificial canals. A total of 120 new D-RaCe DR2 and ProTaper D3 retreatment files were tested in stainless steel artificial canals having 45° and 60° angles of curvature. Thirty instruments of each of the file systems were tested in both angles of curvature (n = 30). The retreatment instruments were rotated until fracture to calculate the number of cycles to failure. The length of each fractured fragment was recorded. Data were analysed by independent sample t-test. Fractured surfaces of the instruments were analysed by scanning electron microscopy. In the canal with 45° angle of curvature, no significant difference was observed between the retreatment systems (P > 0.05); on the other hand, in the canal with 60° angle of curvature, D-RaCe DR2 instruments had greater cyclic fatigue resistance than ProTaper D3 (P  0.05). The fracture surfaces of the instruments had morphologic characteristics of ductile fracture. D-RaCe DR2 instrument exhibited greater cyclic fatigue resistance than ProTaper D3 only in root canals with 60° angle of curvature. © 2015 International Endodontic Journal. Published by John Wiley & Sons Ltd.

  17. The impact of a continuing education programme on the adoption of nickel-titanium rotary instrumentation and root-filling quality amongst a group of Swedish general dental practitioners.

    Science.gov (United States)

    Dahlström, L; Molander, A; Reit, C

    2015-02-01

    The aim of the study was to test the hypothesis that a further education programme relating to nickel-titanium rotary instrumentation (NTRI), with the concurrent activation of social/professional networks amongst all general dental practitioners (GDPs) in a public dental service in Sweden, would increase the adoption rate and improve root-filling quality. To activate the networks, the GDPs at the 25 clinics elected training coaches from amongst themselves. The coaches were educated by a specialist and were then free to organise and conduct the training of the local GDPs. However, collective hands-on training and discussions were mandatory. Lectures were held by an endodontist. The rate of adoption and root-filling quality was evaluated just before and 6 months after the education. Statistical tests were performed with chi-square using a 95% confidence interval. Nickel-titanium rotary instrumentation was adopted by 88%. Excellent root fillings (score 1) increased from 45% to 59% (P = 0.003). The rate of poor-quality root fillings (score 4 and score 5) was not affected. The quality ratio (score 1/score 5) increased from 5.36 (118/22) to 9.5 (133/14). Eleven dentists (17%) at nine different clinics produced 49% of the poor-quality root fillings (score 4 and score 5). Seventy-three per cent of these dentists stated that they had adopted NTRI. The introduction of NTRI will increase the adoption rate and the frequency of good-quality root fillings. However, it will not overcome the problems associated with dentists producing a low-quality level, even if a local professional network is activated. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  18. Advanced rotary engines

    Science.gov (United States)

    Jones, C.

    1983-01-01

    The broad objectives of this paper are the following: (1) to summarize the Curtiss-Wright design, development and field testing background in the area of rotary aircraft engines; (2) to briefly summarize past activity and update development work in the area of stratified charge rotary combustion engines; and (3) to discuss the development of a high-performance direct injected unthrottled stratified charge rotary combustion aircraft engine. Efficiency improvements through turbocharging are also discussed.

  19. Multifuel rotary aircraft engine

    Science.gov (United States)

    Jones, C.; Berkowitz, M.

    1980-01-01

    The broad objectives of this paper are the following: (1) to summarize the Curtiss-Wright design, development and field testing background in the area of rotary aircraft engines; (2) to briefly summarize past activity and update development work in the area of stratified charge rotary combustion engines; and (3) to discuss the development of a high-performance direct injected unthrottled stratified charge rotary combustion aircraft engine. Efficiency improvements through turbocharging are also discussed.

  20. Effect of the size of the apical enlargement with rotary instruments, single-cone filling, post space preparation with drills, fiber post removal, and root canal filling removal on apical crack initiation and propagation.

    Science.gov (United States)

    Çapar, İsmail Davut; Uysal, Banu; Ok, Evren; Arslan, Hakan

    2015-02-01

    The purpose of this study was to investigate the incidence of apical crack initiation and propagation in root dentin after several endodontic procedures. Sixty intact mandibular premolars were sectioned perpendicular to the long axis at 1 mm from the apex, and the apical surface was polished. Thirty teeth were left unprepared and served as a control, and the remaining 30 teeth were instrumented with ProTaper Universal instruments (Dentsply Maillefer, Ballaigues, Switzerland) up to size F5. The root canals were filled with the single-cone technique. Gutta-percha was removed with drills of the Rebilda post system (VOCO, Cuxhaven, Germany). Glass fiber-reinforced composite fiber posts were cemented using a dual-cure resin cement. The fiber posts were removed with a drill of the post system. Retreatment was completed after the removal of the gutta-percha. Crack initiation and propagation in the apical surfaces of the samples were examined with a stereomicroscope after each procedure. The absence/presence of cracks was recorded. Logistic regression was performed to analyze statistically the incidence of crack initiation and propagation with each procedure. The initiation of the first crack and crack propagation was associated with F2 and F4 instruments, respectively. The logistic regression analysis revealed that instrumentation and F2 instrument significantly affected apical crack initiation (P .05). Rotary nickel-titanium instrumentation had a significant effect on apical crack initiation, and post space preparation with drills had a significant impact on crack propagation. Copyright © 2015 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  1. Comparative evaluation of surface changes in four Ni-Ti instruments with successive uses - An SEM study.

    Science.gov (United States)

    Subha, N; Sikri, Vimal K

    2011-07-01

    To evaluate the surface alterations seen in four kinds of Nickel-Titanium (Ni-Ti) instruments using a scanning electron microscope (SEM) for five successive uses in preparing root canals of extracted human molars and also to determine whether the design of the instrument influenced the appearance of defects on the instrument surface. Four different types of instruments namely; ProFile, ProTaper Rotary, ProTaper Hand and K3 Endo were used in 300 mesio-buccal canals. The instruments were examined under the SEM, after every use, to assess the progress of changes on their surfaces for a maximum of five uses. Chi-square test. The most prevalent defects observed were pitting, followed by metal strips. Signs of discontinuity, microfractures and disruption of cutting edge were also evident. Number of defects increased with successive uses. ProTaper Hand showed significantly more microfractures and metal strips than other instruments from third use onwards. ProTaper Rotary and K3 Endo also showed significant changes.

  2. An in-vitro comparison of canal debridement efficiency between three systems of Rotary, Reciprocal and Vertical

    Directory of Open Access Journals (Sweden)

    Sheykhrezaee MS.

    2004-08-01

    Full Text Available Statement of Problem: Total removal of tissues and remnant microorganisms as well as canal shaping are the essential objectives of endodontic therapy. A successful endodontic treatment is obtained through Shilder’s principals, however; complete observation of this technique using stainless steel files manually is problematic and time-consuming. Modern technology, in order to eliminate such problems, has presented new facilities such as Nickel-Titanium (NiTi files and engine driven instruments. Purpose: The aim of this in-vitro study was to compare the canal debridement efficiency of three engine driven instruments: Rotary, Reciprocal and Vertical. Materials and Methods: In this experimental study, 60 mesial roots of human first and second mandibular molars were divided into three groups randomly. In each sample, one canal was considered as case, the other one as control. Files used in Reciprocal and vertical groups were of handy Ni-Ti type and in rotary group, rotary Ni-Ti files were used. After debridement, the roots were sectioned at 3mm and 5mm from anatomic apex, stained and examined under light microscope. Comparison criteria between case and control groups were based on residual debris and predentin and the level of root canal preparation and shaping after debridement. Data were subjected to kruskal-Wallis non-parametric test. Results: There was no significant difference between the efficiency of debridement at 3mm and 5mm sections between all groups. But difference in time consumption was significant ranked from the shortest to the longest as rotary, reciprocal and vertical. Conclusion: The efficiency of debridement between the three automated instruments was approximately equal, however; the instrumentation time was different between three groups. Rotary system was the fastest one, as compared with reciprocal (second and vertical (last. It may be concluded that rotary system has a superiority over the other two groups in conventional

  3. Rotary endodontics in primary teeth – A review

    Science.gov (United States)

    George, Sageena; Anandaraj, S.; Issac, Jyoti S.; John, Sheen A.; Harris, Anoop

    2015-01-01

    Endodontic treatment in primary teeth can be challenging and time consuming, especially during canal preparation, which is considered one of the most important steps in root canal therapy. The conventional instrumentation technique for primary teeth remains the “gold-standard” over hand instrumentation, which makes procedures much more time consuming and adversely affects both clinicians and patients. Recently nickel–titanium (Ni–Ti) rotary files have been developed for use in pediatric endodontics. Using rotary instruments for primary tooth pulpectomies is cost effective and results in fills that are consistently uniform and predictable. This article reviews the use of nickel–titanium rotary files as root canal instrumentation in primary teeth. The pulpectomy technique is described here according to different authors and the advantages and disadvantages of using rotary files are discussed. PMID:26792964

  4. Rotary endodontics in primary teeth – A review

    Directory of Open Access Journals (Sweden)

    Sageena George

    2016-01-01

    Full Text Available Endodontic treatment in primary teeth can be challenging and time consuming, especially during canal preparation, which is considered one of the most important steps in root canal therapy. The conventional instrumentation technique for primary teeth remains the “gold-standard” over hand instrumentation, which makes procedures much more time consuming and adversely affects both clinicians and patients. Recently nickel–titanium (Ni–Ti rotary files have been developed for use in pediatric endodontics. Using rotary instruments for primary tooth pulpectomies is cost effective and results in fills that are consistently uniform and predictable. This article reviews the use of nickel–titanium rotary files as root canal instrumentation in primary teeth. The pulpectomy technique is described here according to different authors and the advantages and disadvantages of using rotary files are discussed.

  5. Rotary combustion device

    NARCIS (Netherlands)

    2008-01-01

    Rotary combustion device (1) with rotary combustion chamber (4). Specific measures are taken to provide ignition of a combustible mixture. It is proposed that a hollow tube be provided coaxially with the axis of rotation (6), so that a small part of the mixture is guided into the combustion chamber.

  6. Comparative analysis of three screening instruments for autism spectrum disorder in toddlers at high risk.

    NARCIS (Netherlands)

    Oosterling, I.J.; Swinkels, S.H.N.; Gaag, R.J. van der; Visser, J.C.; Dietz, C.; Buitelaar, J.K.

    2009-01-01

    Several instruments have been developed to screen for autism spectrum disorders (ASD) in high-risk populations. However, few studies compare different instruments in one sample. Data were gathered from the Early Screening of Autistic Traits Questionnaire, Social Communication Questionnaire,

  7. Piezoelectric Versus Conventional Rotary Techniques for Impacted Third Molar Extraction

    Science.gov (United States)

    Jiang, Qian; Qiu, Yating; Yang, Chi; Yang, Jingyun; Chen, Minjie; Zhang, Zhiyuan

    2015-01-01

    Abstract Impacted third molars are frequently encountered in clinical work. Surgical removal of impacted third molars is often required to prevent clinical symptoms. Traditional rotary cutting instruments are potentially injurious, and piezosurgery, as a new osteotomy technique, has been introduced in oral and maxillofacial surgery. No consistent conclusion has been reached regarding whether this new technique is associated with fewer or less severe postoperative sequelae after third molar extraction. The aim of this study was to compare piezosurgery with rotary osteotomy techniques, with regard to surgery time and the severity of postoperative sequelae, including pain, swelling, and trismus. We conducted a systematic literature search in the Cochrane Library, PubMed, Embase, and Google Scholar. The eligibility criteria of this study included the following: the patients were clearly diagnosed as having impacted mandibular third molars; the patients underwent piezosurgery osteotomy, and in the control group rotary osteotomy techniques, for removing impacted third molars; the outcomes of interest include surgery time, trismus, swelling or pain; the studies are randomized controlled trials. We used random-effects models to calculate the difference in the outcomes, and the corresponding 95% confidence interval. We calculated the weighted mean difference if the trials used the same measurement, and a standardized mean difference if otherwise. A total of seven studies met the eligibility criteria and were included in our analysis. Compared with rotary osteotomy, patients undergoing piezosurgery experienced longer surgery time (mean difference 4.13 minutes, 95% confidence interval 2.75–5.52, P piezosurgery groups. The number of included randomized controlled trials and the sample size of each trial were relatively small, double blinding was not possible, and cost analysis was unavailable due to a lack of data. Our meta-analysis indicates that although patients

  8. Comparing Binaural Pre-processing Strategies I: Instrumental Evaluation.

    Science.gov (United States)

    Baumgärtel, Regina M; Krawczyk-Becker, Martin; Marquardt, Daniel; Völker, Christoph; Hu, Hongmei; Herzke, Tobias; Coleman, Graham; Adiloğlu, Kamil; Ernst, Stephan M A; Gerkmann, Timo; Doclo, Simon; Kollmeier, Birger; Hohmann, Volker; Dietz, Mathias

    2015-12-30

    In a collaborative research project, several monaural and binaural noise reduction algorithms have been comprehensively evaluated. In this article, eight selected noise reduction algorithms were assessed using instrumental measures, with a focus on the instrumental evaluation of speech intelligibility. Four distinct, reverberant scenarios were created to reflect everyday listening situations: a stationary speech-shaped noise, a multitalker babble noise, a single interfering talker, and a realistic cafeteria noise. Three instrumental measures were employed to assess predicted speech intelligibility and predicted sound quality: the intelligibility-weighted signal-to-noise ratio, the short-time objective intelligibility measure, and the perceptual evaluation of speech quality. The results show substantial improvements in predicted speech intelligibility as well as sound quality for the proposed algorithms. The evaluated coherence-based noise reduction algorithm was able to provide improvements in predicted audio signal quality. For the tested single-channel noise reduction algorithm, improvements in intelligibility-weighted signal-to-noise ratio were observed in all but the nonstationary cafeteria ambient noise scenario. Binaural minimum variance distortionless response beamforming algorithms performed particularly well in all noise scenarios. © The Author(s) 2015.

  9. Comparison between high concentration EDTA (24%) and low concentration EDTA (3%) with surfactant upon removal of smear layer after rotary instrumentation: a SEM study.

    Science.gov (United States)

    Daghustani, Mohsen; Alhammadi, Ahmad; Merdad, Khalid; Ohlin, Johan; Erhardt, Fredrik; Ahlquist, Michael

    2011-01-01

    This in vitro study compare cleanliness of tooth canal walls regarding smear layer after final treatment with 24% ethylenediaminetetraaceticacid (EDTA) and 3% EDTA with or without surfactant. Sixty extracted teeth, randomly distributed into four groups, were prepared using ProFile instruments (DENTSPLY, Maillefer, Ballaigues, Switzerland), and subjected to different final irrigation solutions: group A, 24% EDTA; group B, 3% EDTA with surfactant; group C (positive control), 3% EDTA; and group D (negative control), 0.5% sodium hypochlorite. Roots were sectioned, examined and evaluated under scanning electron microscope; microphotographs were taken for the coronal, middle and apical third of each specimen. Statistical analysis showed no difference regarding presence of smear layer between test groups in the coronal and apical sections. They were cleaned in the coronal sections and uncleaned in the apical sections. In the middle section, group B was significantly cleaner (p EDTA did not improve root canal cleanliness and there is no difference between different EDTA concentrations in removing the smear layer.

  10. A novel approach to determine the effect of irrigation on temperature and failure of Ni-Ti endodontic rotary files

    Science.gov (United States)

    Mousavi, Sayed Ali; Kargar-Dehnavi, Vida; Mousavi, Sayed Amir

    2012-01-01

    Background: Nickel-titanium (Ni-Ti) rotary instrument files are important devices in Endodontics in root canal preparation. Ni-Ti file breakage is a critical and problematic issue and irrigation techniques were applied to decrease risk of file failure root. The aim of the present study was to compare the temperature gradient change of different irrigation solutions with Ni-Ti rotary instrument system during root canal preparation and also to define their effects on the file failure. Materials and Methods: A novel computerized instrumentation was utilized and thirty standard (ProFile #25/.04) files were divided into three groups and subjected to a filing in the root canal test. Changes in temperature on teeth under constant instrumental conditions with custom-designed computerized experimental apparatus were measured by using a temperature sensor bonded to the apical hole. A rotary instrument for canal preparation in three series of solution was used and the changes in temperature after each solution were compared. Finally, the file failure results were mentored according to each step of test. Comparisons were performed between group status clinically by using ANOVA (t) test, once the sample showed up normal and differences of Pinstruments, which were immersed in 5% NaOCl, when compared with the water group (Pinstruments immersed in water, when compared with the no solution group (Pinstruments. Conclusion: By immersing the file in 5% NaOCl, the temperature gradient decreased and instrument failure was reduced. PMID:23087732

  11. Evaluation of deformation and fracture of three single-file NiTi rotary instruments: ProTaper F2, WaveOne Primary and OneShape in simulated curved canals

    Directory of Open Access Journals (Sweden)

    Mina A. Shenouda

    2018-06-01

    Full Text Available Purpose. The aim of the current study was to compare the incidence of deformation and fracture in three single-file NiTi instruments: ProTaper F2, WaveOne Primary and OneShape. Methods. Fifteen instruments were equally divided into three groups: ProTaper F2 in reciprocation, WaveOne Primary in reciprocation and OneShape in continuous rotation. Each instrument was used to prepare standardized simulated curved canals in resin blocks until fracture had occurred. Following each canal preparation, the instruments were examined for deformation both by naked eye inspection and stereomicroscopic examination. The average number of canals prepared until the first incidence of cracks and the average lifespan of the instruments were calculated. Data were analysed using one-way ANOVA and two-sample t-test. Results. There was no statistically significant difference between ProTaper and WaveOne instruments in both the incidence of cracks and the average lifespan (P > 0.05. OneShape instruments had a significantly delayed incidence of cracks and a longer lifespan than both ProTaper and WaveOne instruments (P < 0.05; however, OneShape instruments showed a noticeable early plastic deformation. Conclusion: PT F2 instrument was comparable to WO Primary instrument in terms of fracture resistance, while OS instrument had more fracture resistance than both PT F2 and WO Primary instruments.

  12. Evaluation of surface preparation and maintenance of canal curvature following instrumentation with hand ′K′ file and three different Ni-Ti rotary systems: A radiographic and SEM study

    Directory of Open Access Journals (Sweden)

    Namrata Bhatti

    2010-01-01

    Full Text Available Aim: To determine the shaping ability and cleaning efficiency of hand K-flexofiles, ProTaper, LightSpeed and Mtwo instruments during the preparation of curved root canals in extracted human teeth. Materials and Methods: A total of 120 root canals of mandibular and maxillary molars with curvature more than 20° were divided into four groups of 30 each. In group A, canals were prepared using hand K-flexofiles following the crown down technique. In group B LightSpeed, in group C ProTaper, and in group D Mtwo rotary instruments were used to prepare the root canals. Using pre- and post-instrumentation radiographs, straightening of the canal curvature was determined with Corel Draw 9.0 software tools. The amount of debris and smear layer were quantified at three different areas (coronal, middle, and apical thirds of root canal using SEM. The collected data were analyzed statistically using Student′s paired ′t′ test. Results: The mean change in curvature for hand K-files was 7.71°, for ProTaper files 6.03°, for Mtwo 5.43°, and for LightSpeed instruments were found to be 4.57°. The percentage change in the curvature for all the four groups was statistically highly significant (P< 0.01. LightSpeed instruments maintained the original canal curvature significantly (P< 0.01 better than the other instruments. For leftover debris, the minimum percentage was found to be associated with ProTaper (65.48% followed by Mtwo (66.22%, LightSpeed (71.67% and the maximum with hand K-files (74.16%. However, the difference in mean leftover debris between ProTaper and Mtwo was not significant. Conclusion: ProTaper and Mtwo resulted in good cleaning, and LightSpeed maintained the original canal curvature better than the ProTaper, Mtwo, or Hand K-files.

  13. Equations For Rotary Transformers

    Science.gov (United States)

    Salomon, Phil M.; Wiktor, Peter J.; Marchetto, Carl A.

    1988-01-01

    Equations derived for input impedance, input power, and ratio of secondary current to primary current of rotary transformer. Used for quick analysis of transformer designs. Circuit model commonly used in textbooks on theory of ac circuits.

  14. Advanced rotary engine studies

    Science.gov (United States)

    Jones, C.

    1980-01-01

    A review of rotary engine developments relevant to a stratified charge rotary aircraft engine is presented. Advantages in module size and weight, fuel efficiency, reliability, and multi-fuel capability are discussed along with developments in turbocharging, increased mean effective pressure, improved apex seal/trochoid wear surfacing materials, and high strength and temperature aluminum casting alloys. A carbureted prototype aircraft engine is also described.

  15. Quantitative evaluation of apical extrusion of intracanal bacteria using rotary ProTaper, K3XF, twisted and hand K-file system: An ex vivo study

    Directory of Open Access Journals (Sweden)

    Priyanka Ghogre

    2015-01-01

    Conclusions: Both the rotary and hand instrumentation systems extruded intracanal bacteria through the apical foramen. K3XF file system showed least bacterial extrusion amongst all instrumentation groups.

  16. Mechanical reduction of the intracanal Enterococcus faecalis population by Hyflex CM, K3XF, ProTaper Next, and two manual instrument systems: an in vitro comparative study.

    Science.gov (United States)

    Tewari, Rajendra K; Ali, Sajid; Mishra, Surendra K; Kumar, Ashok; Andrabi, Syed Mukhtar-Un-Nisar; Zoya, Asma; Alam, Sharique

    2016-05-01

    In the present study, the effectiveness of three rotary and two manual nickel titanium instrument systems on mechanical reduction of the intracanal Enterococcus faecalis population was evaluated. Mandibular premolars with straight roots were selected. Teeth were decoronated and instrumented until 20 K file and irrigated with physiological saline. After sterilization by ethylene oxide gas, root canals were inoculated with Enterococcus faecalis. The specimens were randomly divided into five groups for canal instrumentation: Manual Nitiflex and Hero Shaper nickel titanium files, and rotary Hyflex CM, ProTaper Next, and K3XF nickel titanium files. Intracanal bacterial sampling was done before and after instrumentation. After serial dilution, samples were plated onto the Mitis Salivarius agar. The c.f.u. grown were counted, and log10 transformation was calculated. All instrumentation systems significantly reduced the intracanal bacterial population after root canal preparation. ProTaper Next was found to be significantly more effective than Hyflex CM and manual Nitiflex and Hero Shaper. However, ProTaper Next showed no significant difference with K3XF. Canal instrumentation by all the file systems significantly reduced the intracanal Enterococcus faecalis counts. ProTaper Next was found to be most effective in reducing the number of bacteria than other rotary or hand instruments. © 2014 Wiley Publishing Asia Pty Ltd.

  17. Assessment of the role of cross section on fatigue resistance of rotary files when used in reciprocation.

    Science.gov (United States)

    Sekar, Vadhana; Kumar, Ranjith; Nandini, Suresh; Ballal, Suma; Velmurugan, Natanasabapathy

    2016-01-01

    The purpose of this study was to assess the role of cross section on cyclic fatigue resistance of One Shape, Revo-S SU, and Mtwo rotary files in continuous rotation and reciprocating motion in dynamic testing model. A total of 90 new rotary One Shape, Revo-S SU, and Mtwo files (ISO size 25, taper 0.06, length 25 mm) were subjected to continuous rotation or reciprocating motion. A cyclic fatigue testing device was fabricated with 60° angle of curvature and 5 mm radius. The dynamic testing of these files was performed using an electric motor which permitted the reproduction of pecking motion. All instruments were rotated or reciprocated until fracture occurred. The time taken for each instrument to fracture was recorded. All the fractured files were analyzed under a scanning electron microscope (SEM) to detect the mode of fracture. Statistical analysis was performed using one-way ANOVA, followed by Tukey's honestly significant difference post hoc test. The time taken for instruments in reciprocating motion to fail under cyclic loading was significantly longer when compared with groups in continuous rotary motion. There was a statistically significant difference between Mtwo rotary and the other two groups in both continuous and reciprocating motion. One Shape rotary files recorded significantly longer duration to fracture resistance when compared with Revo-S SU files in both continuous and reciprocating motion. SEM observations showed that the instruments of all groups had undergone a ductile mode of fracture. Reciprocating motion improved the cyclic fatigue resistance of all tested groups.

  18. Instrumentation

    International Nuclear Information System (INIS)

    Prieur, G.; Nadi, M.; Hedjiedj, A.; Weber, S.

    1995-01-01

    This second chapter on instrumentation gives little general consideration on history and classification of instrumentation, and two specific states of the art. The first one concerns NMR (block diagram of instrumentation chain with details on the magnets, gradients, probes, reception unit). The first one concerns precision instrumentation (optical fiber gyro-meter and scanning electron microscope), and its data processing tools (programmability, VXI standard and its history). The chapter ends with future trends on smart sensors and Field Emission Displays. (D.L.). Refs., figs

  19. A comparative evaluation of root canal area increase using three different nickel-titanium rotary systems: An ex vivo cone-beam computed tomographic analysis

    Directory of Open Access Journals (Sweden)

    Adrija Deka

    2015-01-01

    Full Text Available Background and Objectives: The present study was undertaken to compare and evaluate the area increase of root canals with ProTaper, iRaCe and Revo-S systems using cone beam computed tomography for analysis. Materials and Methodology: Forty five extracted human mandibular premolars having single canal and straight root were collected. Teeth were randomly assigned to three groups (n=15. Samples were decoronized by maintaining root length at 14 mm. Pre-instrumentation cone beam computed tomography scan was done after stabilizing the samples on wax blocks. The working length was determined at 1 mm short from the apical foramen by using a ISO 15 K-file tip protruding at apical foramen. Preparation was carried out according to the manufacturer′s instructions. Finally, canals were instrumented upto 30/.06 apically for each group. After each instrumentation, root canals were irrigated with 2ml of 3% sodium hypochlorite solution followed by 2 ml of 17% EDTA solution. Final irrigation was done with 5ml of saline. Post instrumentation cone beam computed tomography scans of all samples in the 3 groups were acquired. Results: Mean percentage of area increase in different thirds of the canal was highest for ProTaper followed by i-RaCe and Revo-s system which was statistically significant. Interpretation and Conclusion: Root canal area increase was highest for ProTaper followed by i-Race and Revo-S systems.

  20. Apical displacement produced by rotary nickel-titanium instruments and stainless steel files Deslocamento apical produzido por instrumentos de níquel-titânio acionados a motor e limas de aço inoxidável

    Directory of Open Access Journals (Sweden)

    José Roberto Vanni

    2004-03-01

    Full Text Available The aim of this study was to evaluate the apical displacement produced by different rotary nickel-titanium instruments, testing the hypothesis that rotary systems with nickel-titanium instruments produce lower mean values of apical displacement than stainless steel hand instruments. A total of 100 maxillary permanent first molars were selected for the study. The mesiobuccal roots were sectioned at the top cervical third and embedded in blocks of self-curing resin. The specimens were randomly divided into 5 groups and the root canals were prepared using the following nickel-titanium instruments: Group 1 - Quantec system 2000 (Analytic Endodontics, Mexico; Group 2 - Pro-File T.0.04 (Dentsply/Maillefer, Switzerland; Group 3 - Pro-File Series 29 T.0.04 (Dentsply Tulsa, Switzerland; Group 4 - Pow-R T.0.02 (Moyco-Union Broach, USA. Specimens in Group 5 were prepared using stainless steel hand instruments Flexofile (Dentsply/Maillefer, Switzerland. All root canals were previously submitted to cervical preparation using Orifice Shaper instruments #1, 2, 3 and 4 (Dentsply/Maillefer, Switzerland. After odontometry, the remaining root canal was shaped employing increasingly larger instruments, so that the final instrument corresponded to Quantec #9, Pro-File Series 29 #6, and #35 for the other groups. Specimens in Groups 1 to 4 were prepared using an electric handpiece with 16:1 reduction at 350 rpm. The specimens in Group 5 were manually prepared. Apical displacement was measured and recorded by means of radiographic superimposition on a specific desk. Statistical analysis (ANOVA of the results revealed that all groups presented apical displacements. Considering only the nickel-titanium instruments, Group 4 showed the lowest mean value while Groups 2 and 3 produced the highest mean apical displacement values (pO objetivo deste trabalho foi avaliar o deslocamento apical produzido por diferentes instrumentos de níquel-titânio acionadas a motor testando a

  1. Instrumentation

    International Nuclear Information System (INIS)

    Decreton, M.

    2000-01-01

    SCK-CEN's research and development programme on instrumentation aims at evaluating the potentials of new instrumentation technologies under the severe constraints of a nuclear application. It focuses on the tolerance of sensors to high radiation doses, including optical fibre sensors, and on the related intelligent data processing needed to cope with the nuclear constraints. Main achievements in these domains in 1999 are summarised

  2. Instrumentation

    Energy Technology Data Exchange (ETDEWEB)

    Decreton, M

    2001-04-01

    SCK-CEN's research and development programme on instrumentation involves the assessment and the development of sensitive measurement systems used within a radiation environment. Particular emphasis is on the assessment of optical fibre components and their adaptability to radiation environments. The evaluation of ageing processes of instrumentation in fission plants, the development of specific data evaluation strategies to compensate for ageing induced degradation of sensors and cable performance form part of these activities. In 2000, particular emphasis was on in-core reactor instrumentation applied to fusion, accelerator driven and water-cooled fission reactors. This involved the development of high performance instrumentation for irradiation experiments in the BR2 reactor in support of new instrumentation needs for MYRRHA, and for diagnostic systems for the ITER reactor.

  3. Instrumentation

    International Nuclear Information System (INIS)

    Decreton, M.

    2001-01-01

    SCK-CEN's research and development programme on instrumentation involves the assessment and the development of sensitive measurement systems used within a radiation environment. Particular emphasis is on the assessment of optical fibre components and their adaptability to radiation environments. The evaluation of ageing processes of instrumentation in fission plants, the development of specific data evaluation strategies to compensate for ageing induced degradation of sensors and cable performance form part of these activities. In 2000, particular emphasis was on in-core reactor instrumentation applied to fusion, accelerator driven and water-cooled fission reactors. This involved the development of high performance instrumentation for irradiation experiments in the BR2 reactor in support of new instrumentation needs for MYRRHA, and for diagnostic systems for the ITER reactor

  4. Simulation and Optimization of Contactless Power Transfer System for Rotary Ultrasonic Machining

    Directory of Open Access Journals (Sweden)

    Wang Xinwei

    2016-01-01

    Full Text Available In today’s rotary ultrasonic machining (RUM, the power transfer system is based on a contactless power system (rotary transformer rather than the slip ring that cannot cope with high-speed rotary of the tool. The efficiency of the rotary transformer is vital to the whole rotary ultrasonic machine. This paper focused on simulation of the rotary transformer and enhancing the efficiency of the rotary transformer by optimizing three main factors that influence its efficiency, including the gap between the two ferrite cores, the ratio of length and width of the ferrite core and the thickness of ferrite. The finite element model of rotary transformer was built on Maxwell platform. Simulation and optimization work was based on the finite element model. The optimization results compared with the initial simulation result showed an approximate 18% enhancement in terms of efficiency, from 77.69% to 95.2%.

  5. Rotary mechanical latch

    Science.gov (United States)

    Spletzer, Barry L.; Martinez, Michael A.; Marron, Lisa C.

    2012-11-13

    A rotary mechanical latch for positive latching and unlatching of a rotary device with a latchable rotating assembly having a latching gear that can be driven to latched and unlatched states by a drive mechanism such as an electric motor. A cam arm affixed to the latching gear interfaces with leading and trailing latch cams affixed to a flange within the drive mechanism. The interaction of the cam arm with leading and trailing latch cams prevents rotation of the rotating assembly by external forces such as those due to vibration or tampering.

  6. Rotary engine research

    Science.gov (United States)

    1992-06-01

    A development history is presented for NASA's 1983-1991 Rotary Engine Enablement Program, emphasizing the CFD approaches to various problems that were instituted from 1987 to the end of the program. In phase I, a test rig was built to intensively clarify and characterize the stratified-charge rotary engine concept. In phase II, a high pressure, electronically controlled fuel injection system was tested. In phase III, the testing of improved fuel injectors led to the achievement of the stipulated 5 hp/cu inch specific power goal. CFD-aided design of advanced rotor-pocket shapes led to additional performance improvements.

  7. Instrumentation

    International Nuclear Information System (INIS)

    Decreton, M.

    2002-01-01

    SCK-CEN's R and D programme on instrumentation involves the development of advanced instrumentation systems for nuclear applications as well as the assessment of the performance of these instruments in a radiation environment. Particular emphasis is on the use of optical fibres as umbilincal links of a remote handling unit for use during maintanance of a fusion reacor, studies on the radiation hardening of plasma diagnostic systems; investigations on new instrumentation for the future MYRRHA accelerator driven system; space applications related to radiation-hardened lenses; the development of new approaches for dose, temperature and strain measurements; the assessment of radiation-hardened sensors and motors for remote handling tasks and studies of dose measurement systems including the use of optical fibres. Progress and achievements in these areas for 2001 are described

  8. Instrumentation

    Energy Technology Data Exchange (ETDEWEB)

    Decreton, M

    2002-04-01

    SCK-CEN's R and D programme on instrumentation involves the development of advanced instrumentation systems for nuclear applications as well as the assessment of the performance of these instruments in a radiation environment. Particular emphasis is on the use of optical fibres as umbilincal links of a remote handling unit for use during maintanance of a fusion reacor, studies on the radiation hardening of plasma diagnostic systems; investigations on new instrumentation for the future MYRRHA accelerator driven system; space applications related to radiation-hardened lenses; the development of new approaches for dose, temperature and strain measurements; the assessment of radiation-hardened sensors and motors for remote handling tasks and studies of dose measurement systems including the use of optical fibres. Progress and achievements in these areas for 2001 are described.

  9. Instrumentation

    Energy Technology Data Exchange (ETDEWEB)

    Decreton, M

    2000-07-01

    SCK-CEN's research and development programme on instrumentation aims at evaluating the potentials of new instrumentation technologies under the severe constraints of a nuclear application. It focuses on the tolerance of sensors to high radiation doses, including optical fibre sensors, and on the related intelligent data processing needed to cope with the nuclear constraints. Main achievements in these domains in 1999 are summarised.

  10. Instrumentation

    International Nuclear Information System (INIS)

    Umminger, K.

    2008-01-01

    A proper measurement of the relevant single and two-phase flow parameters is the basis for the understanding of many complex thermal-hydraulic processes. Reliable instrumentation is therefore necessary for the interaction between analysis and experiment especially in the field of nuclear safety research where postulated accident scenarios have to be simulated in experimental facilities and predicted by complex computer code systems. The so-called conventional instrumentation for the measurement of e. g. pressures, temperatures, pressure differences and single phase flow velocities is still a solid basis for the investigation and interpretation of many phenomena and especially for the understanding of the overall system behavior. Measurement data from such instrumentation still serves in many cases as a database for thermal-hydraulic system codes. However some special instrumentation such as online concentration measurement for boric acid in the water phase or for non-condensibles in steam atmosphere as well as flow visualization techniques were further developed and successfully applied during the recent years. Concerning the modeling needs for advanced thermal-hydraulic codes, significant advances have been accomplished in the last few years in the local instrumentation technology for two-phase flow by the application of new sensor techniques, optical or beam methods and electronic technology. This paper will give insight into the current state of instrumentation technology for safety-related thermohydraulic experiments. Advantages and limitations of some measurement processes and systems will be indicated as well as trends and possibilities for further development. Aspects of instrumentation in operating reactors will also be mentioned.

  11. The Effect of Canal Preparation with Four Different Rotary Systems on Formation of Dentinal Cracks: An In Vitro Evaluation.

    Science.gov (United States)

    Khoshbin, Elham; Donyavi, Zakiyeh; Abbasi Atibeh, Erfan; Roshanaei, Ghodratollah; Amani, Faranak

    2018-01-01

    Endodontic rotary systems may result in dentinal cracks. They may propagate to vertical root fracture that compromises the outcome of endodontic treatment. This study aimed to compare Neolix and Reciproc (single-file systems), Mtwo and ProTaper (conventional rotary systems) in terms of dentinal crack formation in root canal walls. This in vitro study was conducted on 110 extracted human single-rooted teeth. The teeth were randomly divided into four experimental groups ( n =25) for root canal preparation with Neolix, Reciproc, Mtwo and ProTaper systems and two control groups ( n =5). The first control group underwent root canal instrumentation with hand files while the second control group received no preparation and was only irrigated. After instrumentation, root canals were horizontally sectioned at 3, 6 and 9 mm from the apex and inspected under a stereomicroscope under 12× magnification for detection of cracks. The data were analyzed using Chi-square, GEE test and Bonferroni tests ( P ProTaper, Reciproc, Mtwo and Neolix caused cracks in 92%, 80%, 68% and 48% of samples. ProTaper caused significantly more cracks than Neolix and Mtwo ( P 0.05). All rotary systems cause dentinal cracks and it is significantly different in apical, middle and coronal third of the root. Neolix appears to be a suitable alternative to other rotary systems since use of this single-file system saves time and cost and minimizes trauma to dentinal walls.

  12. Evaluation of the root canal shaping ability of two rotary nickel-titanium systems.

    Science.gov (United States)

    Al-Manei, K K; Al-Hadlaq, S M S

    2014-10-01

    The aim was to investigate the canal shaping abilities of the twisted file (TF) and GT series X file (GTX) systems. Sixty mesial root canals of mandibular molars with curvatures of 15-50° were divided randomly into two groups of 30 canals each. The teeth were sectioned horizontally at 3, 6 and 9 mm from the apex. Root canals were prepared with TF and GTX files, respectively, and the shaping abilities of the systems were evaluated at three levels (coronal, middle and apical) based on the comparison of pre- and post-instrumentation photographs using AutoCAD software. Preparation time was also assessed. Data from the two groups were compared statistically using the Student's t-test. There was no significant difference between the rotary systems in terms of change in root canal cross-sectional area, root canal transportation, centring ability or minimum dentine thickness. Remaining dentine thickness at the coronal and middle levels was similar in the TF and GTX groups, but GTX instruments left significantly less dentine than TF instruments on the mesial aspects of root canals at the apical level. Root canal preparation with TF instruments required significantly less time than with GTX instruments. The TF and GTX NiTi rotary instruments showed similar shaping abilities, but root canal preparation was more rapid with the TF than with the GTX system. © 2014 International Endodontic Journal. Published by John Wiley & Sons Ltd.

  13. Rotary magnetic heat pump

    Science.gov (United States)

    Kirol, L.D.

    1987-02-11

    A rotary magnetic heat pump constructed without flow seals or segmented rotor accomplishes recuperation and regeneration by using split flow paths. Heat exchange fluid pumped through heat exchangers and returned to the heat pump splits into two flow components: one flowing counter to the rotor rotation and one flowing with the rotation. 5 figs.

  14. Rotary pneumatic valve

    Science.gov (United States)

    Hardee, Harry C.

    1991-01-01

    A rotary pneumatic valve which is thrust balanced and the pneumatic pressure developed produces only radial loads on the valve cylinder producing negligible resistance and thus minimal torque on the bearings of the valve. The valve is multiplexed such that at least two complete switching cycles occur for each revolution of the cylinder spindle.

  15. Rotary jagas stipendiume

    Index Scriptorium Estoniae

    2009-01-01

    Pärnu Rotary klubi aastapäevapeol 11. mail Ammende villas anti stipendium viiele Pärnumaa noorele, teiste seas pälvis preemia Pärnu Ülejõe Gümnaasiumi muusikaõpetaja Fred Rõigas ja Pärnu Muusikakoolis trompetit õppiv Chris Sommer

  16. Instruments

    International Nuclear Information System (INIS)

    Buehrer, W.

    1996-01-01

    The present paper mediates a basic knowledge of the most commonly used experimental techniques. We discuss the principles and concepts necessary to understand what one is doing if one performs an experiment on a certain instrument. (author) 29 figs., 1 tab., refs

  17. Comparison of apical transportation and change of working length in K3, NRT AND PROFILE rotary instruments using transparent resin block

    Directory of Open Access Journals (Sweden)

    Min-Jung Yoon

    2011-01-01

    Full Text Available Objectives The purpose of this study is to compare the apical transportation and working length change in curved root canals created in resin blocks, using 3 geometrically different types of Ni-Ti files, K3, NRT, and Profile. Materials and Methods The curvature of 30 resin blocks was measured by Schneider technique and each groups of Ni-Ti files were allocated with 10 resin blocks at random. The canals were shaped with Ni-Ti files by Crown-down technique. It was analyzed by Double radiograph superimposition method (Backman CA 1992, and for the accuracy and consistency, specially designed jig, digital X-ray, and CAD/CAM software for measurement of apical transportation were used. The amount of apical transportation was measured at 0, 1, 3, 5 mm from 'apical foramen - 0.5 mm' area, and the alteration of the working length before and after canal shaping was also measured. For statistics, Kruskal-Wallis One Way Analysis was used. Results There was no significant difference between the groups in the amount of working length change and apical transportation at 0, 1, and 3 mm area (p = 0.027, however, the amount of apical transportation at 5 mm area showed significant difference between K3 and Profile system (p = 0.924. Conclusions As a result of this study, the 3 geometrically different Ni-Ti files showed no significant difference in apical transportation and working length change and maintained the original root canal shape.

  18. Comparison of Piezosurgery and Conventional Rotary Instruments for Removal of Impacted Mandibular Third Molars: A Randomized Controlled Clinical and Radiographic Trial

    Science.gov (United States)

    Shokry, Mohamed; Aboelsaad, Nayer

    2016-01-01

    The purpose of this study was to test the effect of the surgical removal of impacted mandibular third molars using piezosurgery versus the conventional surgical technique on postoperative sequelae and bone healing. Material and Methods. This study was carried out as a randomized controlled clinical trial: split mouth design. Twenty patients with bilateral mandibular third molar mesioangular impaction class II position B indicated for surgical extraction were treated randomly using either the piezosurgery or the conventional bur technique on each site. Duration of the procedure, postoperative edema, trismus, pain, healing, and bone density and quantity were evaluated up to 6 months postoperatively. Results. Test and control sites were compared using paired t-test. There was statistical significance in reduction of pain and swelling in test sites, where the time of the procedure was statistically increased in test site. For bone quantity and quality, statistical difference was found where test site showed better results. Conclusion. Piezosurgery technique improves quality of patient's life in form of decrease of postoperative pain, trismus, and swelling. Furthermore, it enhances bone quality within the extraction socket and bone quantity along the distal aspect of the mandibular second molar. PMID:27597866

  19. Comparison of Piezosurgery and Conventional Rotary Instruments for Removal of Impacted Mandibular Third Molars: A Randomized Controlled Clinical and Radiographic Trial

    Directory of Open Access Journals (Sweden)

    Hani Arakji

    2016-01-01

    Full Text Available The purpose of this study was to test the effect of the surgical removal of impacted mandibular third molars using piezosurgery versus the conventional surgical technique on postoperative sequelae and bone healing. Material and Methods. This study was carried out as a randomized controlled clinical trial: split mouth design. Twenty patients with bilateral mandibular third molar mesioangular impaction class II position B indicated for surgical extraction were treated randomly using either the piezosurgery or the conventional bur technique on each site. Duration of the procedure, postoperative edema, trismus, pain, healing, and bone density and quantity were evaluated up to 6 months postoperatively. Results. Test and control sites were compared using paired t-test. There was statistical significance in reduction of pain and swelling in test sites, where the time of the procedure was statistically increased in test site. For bone quantity and quality, statistical difference was found where test site showed better results. Conclusion. Piezosurgery technique improves quality of patient’s life in form of decrease of postoperative pain, trismus, and swelling. Furthermore, it enhances bone quality within the extraction socket and bone quantity along the distal aspect of the mandibular second molar.

  20. Measuring Medical Housestaff Teamwork Performance Using Multiple Direct Observation Instruments: Comparing Apples and Apples.

    Science.gov (United States)

    Weingart, Saul N; Yaghi, Omar; Wetherell, Matthew; Sweeney, Megan

    2018-04-10

    To examine the composition and concordance of existing instruments used to assess medical teams' performance. A trained observer joined 20 internal medicine housestaff teams for morning work rounds at Tufts Medical Center, a 415-bed Boston teaching hospital, from October through December 2015. The observer rated each team's performance using 9 teamwork observation instruments that examined domains including team structure, leadership, situation monitoring, mutual support, and communication. Observations recorded on paper forms were stored electronically. Scores were normalized from 1 (low) to 5 (high) to account for different rating scales. Overall mean scores were calculated and graphed; weighted scores adjusted for the number of items in each teamwork domain. Teamwork scores were analyzed using t-tests, pair-wise correlations, and the Kruskal-Wallis statistic, and team performance was compared across instruments by domain. The 9 tools incorporated 5 major domains, with 5-35 items per instrument for a total of 161 items per observation session. In weighted and unweighted analyses, the overall teamwork performance score for a given team on a given day varied by instrument. While all of the tools identified the same low outlier, high performers on some instruments were low performers on others. Inconsistent scores for a given team across instruments persisted in domain-level analyses. There was substantial variation in the rating of individual teams assessed concurrently by a single observer using multiple instruments. Since existing teamwork observation tools do not yield concordant assessments, researchers should create better tools for measuring teamwork performance.

  1. Instrumentation

    International Nuclear Information System (INIS)

    Muehllehner, G.; Colsher, J.G.

    1982-01-01

    This chapter reviews the parameters which are important to positron-imaging instruments. It summarizes the options which various groups have explored in designing tomographs and the methods which have been developed to overcome some of the limitations inherent in the technique as well as in present instruments. The chapter is not presented as a defense of positron imaging versus single-photon or other imaging modality, neither does it contain a description of various existing instruments, but rather stresses their common properties and problems. Design parameters which are considered are resolution, sampling requirements, sensitivity, methods of eliminating scattered radiation, random coincidences and attenuation. The implementation of these parameters is considered, with special reference to sampling, choice of detector material, detector ring diameter and shielding and variations in point spread function. Quantitation problems discussed are normalization, and attenuation and random corrections. Present developments mentioned are noise reduction through time-of-flight-assisted tomography and signal to noise improvements through high intrinsic resolution. Extensive bibliography. (U.K.)

  2. Clinical outcome of stand-alone ALIF compared to posterior instrumentation for degenerative disc disease

    DEFF Research Database (Denmark)

    Udby, Peter M.; Bech-Azeddine, Rachid

    2015-01-01

    The objective of the article was to: a) present results from a case cohort pilot study comparing stand-alone ALIF and TLIF and, b) review the literature on studies comparing the clinical outcome of stand-alone ALIF with posterior instrumentation including TLIF or PLIF, in patients with disabling...... low back pain resulting from degenerative disc disease. ALIF surgery has previously been linked with certain high risk complications and unfavorable long term fusion results. Newer studies suggest that stand-alone ALIF can possibly be advantageous compared to other types of posterior instrumented...

  3. Rotary plug seal

    International Nuclear Information System (INIS)

    Ito, Koji; Abiko, Yoshihiro.

    1981-01-01

    Purpose: To enable fuel exchange even upon failure of regular seals and also to enable safety seal exchange by the detection of the reduction in the contact pressure of a rotary plug seal. Constitution: If one of a pair of regular tube seals for the rotary plug is failed during ordinary operation of a FBR type reactor, the reduction in the contact pressure of the seal to the plug gibbousness is detected by a pressure gauge and a solenoid valve is thereby closed. Thus, a back-up-tube seal provided above or below the tube seal is press-contacted by way of argon gas to the gibbousness to enter into operation state and lubricants are supplied from an oil tank. In such a structure, the back-up-tube seal is operated before the failure of the tube seal to enable to continue the fuel exchange work, as well as safety exchange for the tube seal. (Moriyama, K.)

  4. A rotary drive

    International Nuclear Information System (INIS)

    Causer, R.

    1983-01-01

    A rotary drive for a manipulator or teleoperator comprises a ring member freely rotatable about an eccentric boss extending from an input driver shaft. The ring member has a tapered rim portion wedged between two resiliently biassed friction rings of larger diameter than the ring member and coaxial with the driver shaft, and the ring member is rotatably connected to an output driven shaft. The rotary drive provides a considerable velocity ratio, and also provides a safety feature in that friction between the rim portion and the friction rings only causes rotation of the driven shaft if the load on the driven shaft is less than a certain limiting value. This limiting value may be varied by adjusting the resilient bias on the friction rings. (author)

  5. Rotary deformity in degenerative spondylolisthesis

    International Nuclear Information System (INIS)

    Kang, Sung Gwon; Kim, Jeong; Kho, Hyen Sim; Yun, Sung Su; Oh, Jae Hee; Byen, Ju Nam; Kim, Young Chul

    1994-01-01

    We studied to determine whether the degenerative spondylolisthesis has rotary deformity in addition to forward displacement. We have made analysis of difference of rotary deformity between the 31 study groups of symptomatic degenerative spondylolisthesis and 31 control groups without any symptom, statistically. We also reviewed CT findings in 15 study groups. The mean rotary deformity in study groups was 6.1 degree(the standard deviation is 5.20), and the mean rotary deformity in control groups was 2.52 degree(the standard deviation is 2.16)(p < 0.01). The rotary deformity can be accompanied with degenerative spondylolisthesis. We may consider the rotary deformity as a cause of symptomatic degenerative spondylolisthesis in case that any other cause is not detected

  6. Rotary drum for centrifuge

    International Nuclear Information System (INIS)

    Sakurai, Mitsuo; Ichinoto, Seiichi.

    1972-01-01

    An outwardly concaved metallic end plate is fitted into each end of a metallic rotary drum for a centrifuge until each end face of the drum is brought to bear upon a section of the end plate radially projected in a direction perpendicular to the axis of rotation of the drum, said section being provided at the marginal edge of the end plate. Following completion of the fitting operation, the end plate is welded to the rotary drum. During high speed rotation, the drum contracts axially and expands radially, while the concave end plate, radially tensioned due to the radial expansion of the drum, undergoes a reduction in its degree of concavity resulting in outwardly directed axial displacement of the end plate proper its marginal edge remaining unaffected relative to the drum. Such displacement conpensates for axial contraction of the drum. Since displacement of the end plate and contraction of the drum depend upon the speed of rotation, substantial axial distortion of the drum can be avoided relative to the end plates at both low and high speeds to permit a high degree of balance for the rotary drum. (Ohno, Y.)

  7. Comparing NICU teamwork and safety climate across two commonly used survey instruments.

    Science.gov (United States)

    Profit, Jochen; Lee, Henry C; Sharek, Paul J; Kan, Peggy; Nisbet, Courtney C; Thomas, Eric J; Etchegaray, Jason M; Sexton, Bryan

    2016-12-01

    Measurement and our understanding of safety culture are still evolving. The objectives of this study were to assess variation in safety and teamwork climate and in the neonatal intensive care unit (NICU) setting, and compare measurement of safety culture scales using two different instruments (Safety Attitudes Questionnaire (SAQ) and Hospital Survey on Patient Safety Culture (HSOPSC)). Cross-sectional survey study of a voluntary sample of 2073 (response rate 62.9%) health professionals in 44 NICUs. To compare survey instruments, we used Spearman's rank correlation coefficients. We also compared similar scales and items across the instruments using t tests and changes in quartile-level performance. We found significant variation across NICUs in safety and teamwork climate scales of SAQ and HSOPSC (pteamwork scales (teamwork climate and teamwork within units) of the two instruments correlated strongly (safety r=0.72, pteamwork r=0.67, p<0.001). However, the means and per cent agreements for all scale scores and even seemingly similar item scores were significantly different. In addition, comparisons of scale score quartiles between the two instruments revealed that half of the NICUs fell into different quartiles when translating between the instruments. Large variation and opportunities for improvement in patient safety culture exist across NICUs. Important systematic differences exist between SAQ and HSOPSC such that these instruments should not be used interchangeably. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

  8. Cyclic fatigue resistance, torsional resistance, and metallurgical characteristics of M3 Rotary and M3 Pro Gold NiTi files

    Science.gov (United States)

    2018-01-01

    Objectives To evaluate the mechanical properties and metallurgical characteristics of the M3 Rotary and M3 Pro Gold files (United Dental). Materials and Methods One hundred and sixty new M3 Rotary and M3 Pro Gold files (sizes 20/0.04 and 25/0.04) were used. Torque and angle of rotation at failure (n = 20) were measured according to ISO 3630-1. Cyclic fatigue resistance was tested by measuring the number of cycles to failure in an artificial stainless steel canal (60° angle of curvature and a 5-mm radius). The metallurgical characteristics were investigated by differential scanning calorimetry. Data were analyzed using analysis of variance and the Student-Newman-Keuls test. Results Comparing the same size of the 2 different instruments, cyclic fatigue resistance was significantly higher in the M3 Pro Gold files than in the M3 Rotary files (p Rotary files showed 1 small peak on the heating curve and 1 small peak on the cooling curve. Conclusions The M3 Pro Gold files showed greater flexibility and angular rotation than the M3 Rotary files, without decrement of their torque resistance. The superior flexibility of M3 Pro Gold files can be attributed to their martensite phase. PMID:29765904

  9. Environmental policy instruments and technological change in the energy sector: findings from comparative empirical research

    International Nuclear Information System (INIS)

    Skjaerseth, J.B.; Christiansen, A.C.

    2006-01-01

    This article explores the extent to which and in what ways environmental policy instruments may affect patterns of environmental friendly technological change in the energy sector. Our argument is based on the assumption, however, that technological change is also affected by the political context in which the instruments are applied and by the nature of the problem itself. Comparative empirical research involving different European countries, sectors and policy fields were examined, including climate change, air pollution and wind power. The relationship between environmental policy instruments and technological change is extremely complex, not least due to the impact of other factors that may be more decisive than environmental ones. Against this backdrop, it was concluded that: 1) a portfolio of policy instruments works to the extent that different types of policy instruments affect the different drivers and stages behind technological change needed to solve specific problems. The need for a portfolio of policy instruments depends on the technological challenge being faced; 2) voluntary approaches facilitated constructive corporate strategies, but mandatory approaches tended to be more effective in stimulating short term major technological change; 3) voluntary approaches work well in the short term when the problem to be solved is characterized by lack of information and coordination. (author)

  10. Lumbar lordosis restoration following single-level instrumented fusion comparing 4 commonly used techniques.

    Science.gov (United States)

    Dimar, John R; Glassman, Steven D; Vemuri, Venu M; Esterberg, Justin L; Howard, Jennifer M; Carreon, Leah Y

    2011-11-09

    A major sequelae of lumbar fusion is acceleration of adjacent-level degeneration due to decreased lumbar lordosis. We evaluated the effectiveness of 4 common fusion techniques in restoring lordosis: instrumented posterolateral fusion, translumbar interbody fusion, anteroposterior fusion with posterior instrumentation, and anterior interbody fusion with lordotic threaded (LT) cages (Medtronic Sofamor Danek, Memphis, Tennessee). Radiographs were measured preoperatively, immediately postoperatively, and a minimum of 6 months postoperatively. Parameters measured included anterior and posterior disk space height, lumbar lordosis from L3 to S1, and surgical level lordosis.No significant difference in demographics existed among the 4 groups. All preoperative parameters were similar among the 4 groups. Lumbar lordosis at final follow-up showed no difference between the anteroposterior fusion with posterior instrumentation, translumbar interbody fusion, and LT cage groups, although the posterolateral fusion group showed a significant loss of lordosis (-10°) (Plordosis and showed maintenance of anterior and posterior disk space height postoperatively compared with the other groups. Instrumented posterolateral fusion produces a greater loss of lordosis compared with anteroposterior fusion with posterior instrumentation, translumbar interbody fusion, and LT cages. Maintenance of lordosis and anterior and posterior disk space height is significantly better with anterior interbody fusion with LT cages. Copyright 2011, SLACK Incorporated.

  11. Lightweight Low Force Rotary Percussive Coring Tool for Planetary Applications, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Alliance Spacesystems, LLC produced a rotary percussive drill designed for space use under a NASA-funded Mars Instrument Development Program (MIDP) project -- the...

  12. BIOMATERIALS FOR ROTARY BLOOD PUMPS

    NARCIS (Netherlands)

    VANOEVEREN, W

    Rotary blood pumps are used for cardiac assist and cardiopulmonary support since mechanical blood damage is less than with conventional roller pumps. The high shear rate in the rotary pump and the reduced anticoagulation of the patient during prolonged pumping enforces high demands on the

  13. Rotary core drills

    Energy Technology Data Exchange (ETDEWEB)

    1967-11-30

    The design of a rotary core drill is described. Primary consideration is given to the following component parts of the drill: the inner and outer tube, the core bit, an adapter, and the core lifter. The adapter has the form of a downward-converging sleeve and is mounted to the lower end of the inner tube. The lifter, extending from the adapter, is split along each side so that it can be held open to permit movement of a core. It is possible to grip a core by allowing the lifter to assume a closed position.

  14. Rotary engine cooling system

    Science.gov (United States)

    Jones, Charles (Inventor); Gigon, Richard M. (Inventor); Blum, Edward J. (Inventor)

    1985-01-01

    A rotary engine has a substantially trochoidal-shaped housing cavity in which a rotor planetates. A cooling system for the engine directs coolant along a single series path consisting of series connected groups of passages. Coolant enters near the intake port, passes downwardly and axially through the cooler regions of the engine, then passes upwardly and axially through the hotter regions. By first flowing through the coolest regions, coolant pressure is reduced, thus reducing the saturation temperature of the coolant and thereby enhancing the nucleate boiling heat transfer mechanism which predominates in the high heat flux region of the engine during high power level operation.

  15. High speed rotary drum

    Energy Technology Data Exchange (ETDEWEB)

    Sagara, H

    1970-03-25

    A high speed rotary drum is disclosed in which the rotor vessel is a double-wall structure comprising an inner wave-shaped pipe inserted coaxially within an outer straight pipe, the object being to provide a strengthened composite light-weight structure. Since force induced axial deformation of the straight pipe and radial deformation of the corrugated pipe are small, the composite effectively resists external forces and, if the waves of the inner pipe are given a sufficient amplitude, the thickness of both pipes may be reduced to lower the overall weight. Thus high angular velocities can be obtained to separate U/sup 235/ from gaseous UF/sub 6/.

  16. Rotary kiln arrangements

    International Nuclear Information System (INIS)

    Hayes, M.R.

    1983-01-01

    In a rotary kiln arrangement in which a reaction is to occur between counterflowing reactants and material is discharged through a hopper, an injector for at least one reactant extends into a reaction zone of the kiln, means being provided for the reaction zone to be maintained within a desired temperature range. The said means includes heating elements for adjusting the temperature of the injected reactant to a temperature within the desired range while it is in the injector. The arrangement may be used in the production of uranium oxides from uranium hexafluoride. (author)

  17. Apical extrusion of debris using reciprocating files and rotary ...

    African Journals Online (AJOL)

    Procedure: Sixty extracted human mandibular premolars were used. The root canals were instrumented using reciprocating (WaveOne, Reciproc, SafeSider) or rotary ... and cross‑sections, and kinematics, and this situation may influence the amount of apically extruded debris through the apical foramen.[15]. The aim of this ...

  18. Performing T-tests to Compare Autocorrelated Time Series Data Collected from Direct-Reading Instruments.

    Science.gov (United States)

    O'Shaughnessy, Patrick; Cavanaugh, Joseph E

    2015-01-01

    Industrial hygienists now commonly use direct-reading instruments to evaluate hazards in the workplace. The stored values over time from these instruments constitute a time series of measurements that are often autocorrelated. Given the need to statistically compare two occupational scenarios using values from a direct-reading instrument, a t-test must consider measurement autocorrelation or the resulting test will have a largely inflated type-1 error probability (false rejection of the null hypothesis). A method is described for both the one-sample and two-sample cases which properly adjusts for autocorrelation. This method involves the computation of an "equivalent sample size" that effectively decreases the actual sample size when determining the standard error of the mean for the time series. An example is provided for the one-sample case, and an example is given where a two-sample t-test is conducted for two autocorrelated time series comprised of lognormally distributed measurements.

  19. Diabetes and quality of life: Comparing results from utility instruments and Diabetes-39.

    Science.gov (United States)

    Chen, Gang; Iezzi, Angelo; McKie, John; Khan, Munir A; Richardson, Jeff

    2015-08-01

    To compare the Diabetes-39 (D-39) with six multi-attribute utility (MAU) instruments (15D, AQoL-8D, EQ-5D, HUI3, QWB, and SF-6D), and to develop mapping algorithms which could be used to transform the D-39 scores into the MAU scores. Self-reported diabetes sufferers (N=924) and members of the healthy public (N=1760), aged 18 years and over, were recruited from 6 countries (Australia 18%, USA 18%, UK 17%, Canada 16%, Norway 16%, and Germany 15%). Apart from the QWB which was distributed normally, non-parametric rank tests were used to compare subgroup utilities and D-39 scores. Mapping algorithms were estimated using ordinary least squares (OLS) and generalised linear models (GLM). MAU instruments discriminated between diabetes patients and the healthy public; however, utilities varied between instruments. The 15D, SF-6D, AQoL-8D had the strongest correlations with the D-39. Except for the HUI3, there were significant differences by gender. Mapping algorithms based on the OLS estimator consistently gave better goodness-of-fit results. The mean absolute error (MAE) values ranged from 0.061 to 0.147, the root mean square error (RMSE) values 0.083 to 0.198, and the R-square statistics 0.428 and 0.610. Based on MAE and RMSE values the preferred mapping is D-39 into 15D. R-square statistics and the range of predicted utilities indicate the preferred mapping is D-39 into AQoL-8D. Utilities estimated from different MAU instruments differ significantly and the outcome of a study could depend upon the instrument used. The algorithms reported in this paper enable D-39 data to be mapped into utilities predicted from any of six instruments. This provides choice for those conducting cost-utility analyses. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  20. Rotary spin echoes

    Energy Technology Data Exchange (ETDEWEB)

    Solomon, I. [Commissariat a l' energie atomique et aux energies alternatives - CEA, Centre d' Etudes Nucleaires de Saclay, BP2, Gif-sur-Yvette (France)

    1959-07-01

    Torrey has observed the free precession of nuclear spins around an r-f field H{sub 1}, fixed in a frame rotating at the Larmor frequency ω{sub 0} = γH{sub 0} around a large d-c magnetic field H{sub 0}. He showed that for an H{sub 1}, much larger than inhomogeneity of H{sub 0}, the latter has a negligible effect on the decay of the spin magnetization which is mainly due to the inhomogeneity of H{sub 1}. We report here on a method of overcoming the inhomogeneity of H{sub 1}, by production of echoes in the rotating frame ('rotary echoes'). These echoes are obtained by a 180 deg. phase shift at t = τ on the r-f field so that H{sub 1}, is suddenly reversed, producing a re-focussing of the magnetization vectors at the time t = 2 τ. The rotary echoes so obtained are very similar to the usual spin-echoes with, however some specific features that make them particularly suitable for the measurement of long relaxation times. Reprint of a paper published in Physical Review Letters, vol. 2, no. 7, Apr 1959, p. 301-302.

  1. Rotary spin echoes

    International Nuclear Information System (INIS)

    Solomon, I.

    1959-01-01

    Torrey has observed the free precession of nuclear spins around an r-f field H 1 , fixed in a frame rotating at the Larmor frequency ω 0 = γH 0 around a large d-c magnetic field H 0 . He showed that for an H 1 , much larger than inhomogeneity of H 0 , the latter has a negligible effect on the decay of the spin magnetization which is mainly due to the inhomogeneity of H 1 . We report here on a method of overcoming the inhomogeneity of H 1 , by production of echoes in the rotating frame ('rotary echoes'). These echoes are obtained by a 180 deg. phase shift at t = τ on the r-f field so that H 1 , is suddenly reversed, producing a re-focussing of the magnetization vectors at the time t = 2 τ. The rotary echoes so obtained are very similar to the usual spin-echoes with, however some specific features that make them particularly suitable for the measurement of long relaxation times. Reprint of a paper published in Physical Review Letters, vol. 2, no. 7, Apr 1959, p. 301-302

  2. Ex Vivo Comparison of Mtwo and RaCe Rotary File Systems in Root Canal Deviation: One File Only versus the Conventional Method.

    Science.gov (United States)

    Aminsobhani, Mohsen; Razmi, Hasan; Nozari, Solmaz

    2015-07-01

    Cleaning and shaping of the root canal system is an important step in endodontic therapy. New instruments incorporate new preparation techniques that can improve the efficacy of cleaning and shaping. The aim of this study was to compare the efficacy of Mtwo and RaCe rotary file systems in straightening the canal curvature using only one file or the conventional method. Sixty mesial roots of extracted human mandibular molars were prepared by RaCe and Mtwo nickel-titanium (NiTi) rotary files using the conventional and only one rotary file methods. The working length was 18 mm and the curvatures of the root canals were between 15-45°. By superimposing x-ray images before and after the instrumentation, deviation of the canals was assessed using Adobe Photoshop CS3 software. Preparation time was recorded. Data were analyzed using three-way ANOVA and Tukey's post hoc test. There were no significant differences between RaCe and Mtwo or between the two root canal preparation methods in root canal deviation in buccolingual and mesiodistal radiographs (P>0.05). Changes of root canal curvature in >35° subgroups were significantly more than in other subgroups with smaller canal curvatures. Preparation time was shorter in one file only technique. According to the results, the two rotary systems and the two root canal preparation methods had equal efficacy in straightening the canals; but the preparation time was shorter in one file only group.

  3. Technical quality of root canal treatment of posterior teeth after rotary or hand preparation by fifth year undergraduate students, The University of Jordan.

    Science.gov (United States)

    Abu-Tahun, Ibrahim; Al-Rabab'ah, Mohammad A; Hammad, Mohammad; Khraisat, Ameen

    2014-12-01

    The aim of this study was to investigate the technical quality of root canal treatment provided by the undergraduate students as their first experience in molar endodontics using nickel-titanium (NiTi) files in a crown-down approach compared with stainless steel standard technique. This study was carried out by the fifth year undergraduate students attending peer review sessions as a part of their training programme, using two different questionnaires to assess the overall technical quality and potential problems regarding endodontic complications after root canal preparation with these two techniques. The overall results indicated a statistically significant difference in the performance of the two instrument techniques in difficult cases showing better performance of the NiTi system and mean rotary preparation time (P ProTaper rotary files, were able to prepare root canals faster with more preparation accuracy compared with canals of same teeth prepared with hand instruments. © 2014 Australian Society of Endodontology.

  4. Rotary endodontics in primary teeth – A review

    OpenAIRE

    Sageena George; S. Anandaraj; Jyoti S. Issac; Sheen A. John; Anoop Harris

    2016-01-01

    Endodontic treatment in primary teeth can be challenging and time consuming, especially during canal preparation, which is considered one of the most important steps in root canal therapy. The conventional instrumentation technique for primary teeth remains the “gold-standard” over hand instrumentation, which makes procedures much more time consuming and adversely affects both clinicians and patients. Recently nickel–titanium (Ni–Ti) rotary files have been developed for use in pediatric endod...

  5. Intercomparison of two comparative reactivity method instruments inf the Mediterranean basin during summer 2013

    Science.gov (United States)

    Zannoni, N.; Dusanter, S.; Gros, V.; Sarda Esteve, R.; Michoud, V.; Sinha, V.; Locoge, N.; Bonsang, B.

    2015-09-01

    The hydroxyl radical (OH) plays a key role in the atmosphere, as it initiates most of the oxidation processes of volatile organic compounds (VOCs), and can ultimately lead to the formation of ozone and secondary organic aerosols (SOAs). There are still uncertainties associated with the OH budget assessed using current models of atmospheric chemistry and direct measurements of OH sources and sinks have proved to be valuable tools to improve our understanding of the OH chemistry. The total first order loss rate of OH, or total OH reactivity, can be directly measured using three different methods, such as the following: total OH loss rate measurement, laser-induced pump and probe technique and comparative reactivity method. Observations of total OH reactivity are usually coupled to individual measurements of reactive compounds in the gas phase, which are used to calculate the OH reactivity. Studies using the three methods have highlighted that a significant fraction of OH reactivity is often not explained by individually measured reactive compounds and could be associated to unmeasured or unknown chemical species. Therefore accurate and reproducible measurements of OH reactivity are required. The comparative reactivity method (CRM) has demonstrated to be an advantageous technique with an extensive range of applications, and for this reason it has been adopted by several research groups since its development. However, this method also requires careful corrections to derive ambient OH reactivity. Herein we present an intercomparison exercise of two CRM instruments, CRM-LSCE (Laboratoire des Sciences du Climat et de l'Environnement) and CRM-MD (Mines Douai), conducted during July 2013 at the Mediterranean site of Ersa, Cape Corsica, France. The intercomparison exercise included tests to assess the corrections needed by the two instruments to process the raw data sets as well as OH reactivity observations. The observation was divided in three parts: 2 days of plant

  6. Rotary shaft seal

    International Nuclear Information System (INIS)

    Langebrake, C.O.

    1984-01-01

    The invention is a novel rotary shaft seal assembly which provides positive-contact sealing when the shaft is not rotated and which operates with its sealing surfaces separated by a film of compressed ambient gas whose width is independent of the speed of shaft rotation. In a preferred embodiment, the assembly includes a disc affixed to the shaft for rotation therewith. Axially movable, non-rotatable plates respectively supported by sealing bellows are positioned on either side of the disc to be in sealing engagement therewith. Each plate carries piezoelectric transducer elements which are electrically energized at startup to produce films of compressed ambient gas between the confronting surfaces of the plates and the disc. Following shutdown of the shaft, the transducer elements are de-energized. A control circuit responds to incipient rubbing between the plate and either disc by altering the electrical input to the transducer elements to eliminate rubbing

  7. Comparative evaluation of rotary ProTaper, Profile, and conventional stepback technique on reduction in Enterococcus faecalis colony-forming units and vertical root fracture resistance of root canals.

    Science.gov (United States)

    Singla, Mamta; Aggarwal, Vivek; Logani, Ajay; Shah, Naseem

    2010-03-01

    The purpose of this in vitro study was to evaluate the effect of various root canal instrumentation techniques with different instrument tapers on cleaning efficacy and resultant vertical root fracture (VRF) strength of the roots. Fifty human mandibular first premolar roots were enlarged to ISO size 20, inoculated with Enterococcus faecalis [ATCC2912] for 72 hours and divided into 5 groups: group I: prepared with .02 taper hand instruments ISO size 40; group II: Profile .04 taper size 40; group III: Profile .06 taper size 40; group IV: ProTaper size F4; and group V (control group) further divided into: Va: with bacterial inoculation and no mechanical instrumentation; and Group Vb: neither bacterial inoculation nor mechanical instrumentation. Cleaning efficacy was evaluated in terms of reduction of colony forming units (CFUs). The VRF strength was evaluated using D11 spreader as wedge in an Instron testing machine. Root canals instrumented with ProTaper and 6% Profile instruments showed maximum reduction in CFUs, with statistically insignificant difference between them. The VRF resistance decreased in all instrumented groups. The difference of VRF between 2% and 4% taper Profile groups was statistically insignificant (P = .195). One-way analysis of variance showed that canals instrumented with ProTaper F4 showed maximum reduction in VRF resistance compared with control uninstrumented group. Profile 6% taper instruments offer the advantage of maximum debridement without significant reduction in root fracture resistance. Copyright 2010 Mosby, Inc. All rights reserved.

  8. Incidence of microcracks in maxillary first premolars after instrumentation with three different mechanized file systems: a comparative ex vivo study.

    Science.gov (United States)

    Kfir, A; Elkes, D; Pawar, A; Weissman, A; Tsesis, I

    2017-01-01

    The objective of this study is to determine the potential for microcracks in the radicular dentin of first maxillary premolars using three different mechanized endodontic instrumentation systems. Eighty extracted maxillary first premolars with two root canals and no externally visible microcracks were selected. Root canal instrumentation was performed with either the ProTaper file system, the WaveOne primary file, or the self-adjusting file (SAF). Teeth with intact roots served as controls. The roots were cut into segments and examined with an intensive, small-diameter light source that was applied diagonally to the entire periphery of the root slice under ×20 magnification; the presence of microcracks and fractures was recorded. Pearson's chi-square method was used for statistical analysis, and significance was set at p systems, respectively, while no microcracks were present in the roots treated with the SAF (p = 0.008 and p = 0.035, respectively). Intact teeth presented with cracks in 5 % of the roots. The intensive, small-diameter light source revealed microcracks that could not be detected when using the microscope's light alone. Within the limitations of this study, it could be concluded that mechanized root canal instrumentation with the ProTaper and WaveOne systems in maxillary first premolars causes microcracks in the radicular dentin, while the use of the SAF file causes no such microcracks. Rotary and reciprocating files with large tapers may cause microcracks in the radicular dentin of maxillary first premolars. Less aggressive methods should be considered for these teeth.

  9. Experimental analysis of IMEP in a rotary combustion engine

    Science.gov (United States)

    Schock, H. J.; Rice, W. J.; Meng, P. R.

    1981-01-01

    A real time indicated mean effective pressure measurement system is described which is used to judge proposed improvements in cycle efficiency of a rotary combustion engine. This is the first self-contained instrument that is capable of making real time measurements of IMEP in a rotary engine. Previous methods used require data recording and later processing using a digital computer. The unique features of this instrumentation include its ability to measure IMEP on a cycle by cycle, real time basis and the elimination of the need to differentiate volume function in real time. Measurements at two engine speeds (2000 and 3000 rpm) and a full range of loads are presented, although the instrument was designed to operate to speeds of 9000 rpm.

  10. Comparing Diagnostic Accuracy of Cognitive Screening Instruments: A Weighted Comparison Approach

    Directory of Open Access Journals (Sweden)

    A.J. Larner

    2013-03-01

    Full Text Available Background/Aims: There are many cognitive screening instruments available to clinicians when assessing patients' cognitive function, but the best way to compare the diagnostic utility of these tests is uncertain. One method is to undertake a weighted comparison which takes into account the difference in sensitivity and specificity of two tests, the relative clinical misclassification costs of true- and false-positive diagnosis, and also disease prevalence. Methods: Data were examined from four pragmatic diagnostic accuracy studies from one clinic which compared the Mini-Mental State Examination (MMSE with the Addenbrooke's Cognitive Examination-Revised (ACE-R, the Montreal Cognitive Assessment (MoCA, the Test Your Memory (TYM test, and the Mini-Mental Parkinson (MMP, respectively. Results: Weighted comparison calculations suggested a net benefit for ACE-R, MoCA, and MMP compared to MMSE, but a net loss for TYM test compared to MMSE. Conclusion: Routine incorporation of weighted comparison or other similar net benefit measures into diagnostic accuracy studies merits consideration to better inform clinicians of the relative value of cognitive screening instruments.

  11. Cyclic fatigue resistance of RaCe and Mtwo rotary files in continuous rotation and reciprocating motion.

    Science.gov (United States)

    Vadhana, Sekar; SaravanaKarthikeyan, Balasubramanian; Nandini, Suresh; Velmurugan, Natanasabapathy

    2014-07-01

    The purpose of this study was to evaluate and compare the cyclic fatigue resistance of RaCe (FKG Dentaire, La Chaux-de-Fonds, Switzerland) and Mtwo (VDW, Munich, Germany) rotary files in continuous rotation and reciprocating motion. A total of 60 new rotary Mtwo and RaCe files (ISO size = 25, taper = 0.06, length = 25 mm) were selected and randomly divided into 4 groups (n = 15 each): Mtc (Mtwo NiTi files in continuous rotation), Rc (RaCe NiTi files in continuous rotation), Mtr (Mtwo NiTi files in reciprocating motion), and Rr (RaCe NiTi files in reciprocating motion). A cyclic fatigue testing device was fabricated with a 60° angle of curvature and a 5-mm radius. All instruments were rotated or reciprocated until fracture occurred. The time taken for each instrument to fracture and the length of the broken fragments were recorded. All the fractured files were analyzed under a scanning electron microscope to detect the mode of fracture. The Kolmogorov-Smirnov test was used to assess the normality of samples distribution, and statistical analysis was performed using the independent sample t test. The time taken for the instruments of the Mtr and Rr groups to fail under cyclic loading was significantly longer compared with the Mtc and Rc groups (P ductile mode of fracture. The length of the fractured segments was between 5 and 6 mm, which was not statistically significant among the experimental groups. Mtwo and RaCe rotary instruments showed a significantly higher cyclic fatigue resistance in reciprocating motion compared with continuous rotation motion. Copyright © 2014 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  12. Apical extrusion of intracanal debris using two engine driven and step-back instrumentation techniques: an in-vitro study.

    Science.gov (United States)

    Kustarci, Alper; Akdemir, Neslihan; Siso, Seyda Herguner; Altunbas, Demet

    2008-10-01

    The purpose of this study was to compare in-vitro the amount of debris extruded apically from extracted teeth, using K3, Protaper rotary instruments and manual step-back technique. Forty five human single-rooted mandibular premolar teeth were randomly divided into 3 groups. The teeth in 3 groups were instrumented until reaching the working length with K3, Protaper rotary instruments and K-type stainless steel instruments with manual step-back technique, respectively. Debris extruded from the apical foramen was collected into centrifuge tubes and the amount was determined. The data obtained were analyzed using Kruskal-Wallis one-way analysis of variance and Mann-Whitney U tests, with P=.05 as the level for statistical significance. Statistically significant difference was observed between K3, Protaper and step-back groups in terms of debris extrusion (PStep-back group had the highest mean debris weight, which was significantly different from the K3 and Protaper groups (Pengine-driven Ni-Ti systems extruded significantly less apical debris than step-back technique. However, Protaper rotary instruments extruded significantly more debris than K3 rotary instruments.

  13. Comparative instrumental evaluation of efficacy and safety between a binary and a ternary system in chemexfoliation.

    Science.gov (United States)

    Cameli, Norma; Mariano, Maria; Ardigò, Marco; Corato, Cristina; De Paoli, Gianfranco; Berardesca, Enzo

    2017-09-20

    To instrumentally evaluate the efficacy and the safety of a new ternary system chemo exfoliating formulation (water-dimethyl isosorbide-acid) vs traditional binary systems (water and acid) where the acid is maintained in both the systems at the same concentration. Different peelings (binary system pyruvic acid and trichloroacetic acid-TCA, and ternary system pyruvic acid and TCA) were tested on the volar forearm of 20 volunteers of both sexes between 28 and 50 years old. The outcomes were evaluated at the baseline, 10 minutes, 24 hours, and 1 week after the peeling by means of noninvasive skin diagnosis techniques. In vivo reflectance confocal microscopy was used for stratum corneum evaluation, transepidermal waterloss, and Corneometry for skin barrier and hydration, Laser Doppler velocimetry in association with colorimetry for irritation and erythema analysis. The instrumental data obtained showed that the efficacy and safety of the new ternary system peel compounds were significantly higher compared with the binary system formulations tested. The new formulation peels improved chemexfoliation and reduced complications such as irritation, redness, and postinflammatory pigmentation compared to the traditional aqueous solutions. The study showed that ternary system chemexfoliation, using a controlled delivery technology, was able to provide the same clinical effects in term of stratum corneum reduction with a significantly reduced barrier alteration, water loss, and irritation/erythema compared to traditional binary system peels. © 2017 Wiley Periodicals, Inc.

  14. Dynamic Torque and Vertical Force Analysis during Nickel-titanium Rotary Root Canal Preparation with Different Modes of Reciprocal Rotation.

    Science.gov (United States)

    Tokita, Daisuke; Ebihara, Arata; Nishijo, Miki; Miyara, Kana; Okiji, Takashi

    2017-10-01

    The purpose of the present study was to compare 2 modes of reciprocal movement (torque-sensitive and time-dependent reciprocal rotation) with continuous rotation in terms of torque and apical force generation during nickel-titanium rotary root canal instrumentation. A custom-made automated root canal instrumentation and torque/force analyzing device was used to prepare simulated canals in resin blocks and monitor the torque and apical force generated in the blocks during preparation. Experimental groups (n = 7, each) consisted of (1) torque-sensitive reciprocal rotation with torque-sensitive vertical movement (group TqR), (2) time-dependent reciprocal rotation with time-dependent vertical movement (group TmR), and (3) continuous rotation with time-dependent vertical movement (group CR). The canals were instrumented with TF Adaptive SM1 and SM2 rotary files (SybronEndo, Orange, CA), and the torque and apical force were measured during instrumentation with SM2. The mean and maximum torque and apical force values were statistically analyzed using 1-way analysis of variance and the Tukey test (α = 0.05). The recordings showed intermittent increases of upward apical force and clockwise torque, indicating the generation and release of screw-in forces. The maximum upward apical force values in group TmR were significantly smaller than those in group CR (P forces when compared with continuous rotation. Copyright © 2017 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  15. MEMS Rotary Engine Power System

    Science.gov (United States)

    Fernandez-Pello, A. Carlos; Pisano, Albert P.; Fu, Kelvin; Walther, David C.; Knobloch, Aaron; Martinez, Fabian; Senesky, Matt; Stoldt, Conrad; Maboudian, Roya; Sanders, Seth; Liepmann, Dorian

    This work presents a project overview and recent research results for the MEMS Rotary Engine Power System project at the Berkeley Sensor & Actuator Center of the University of California at Berkeley. The research motivation for the project is the high specific energy density of hydrocarbon fuels. When compared with the energy density of batteries, hydrocarbon fuels may have as much as 20x more energy. However, the technical challenge is the conversion of hydrocarbon fuel to electricity in an efficient and clean micro engine. A 12.9 mm diameter Wankel engine will be shown that has already generated 4 Watts of power at 9300rpm. In addition, the 1mm and 2.4 mm Wankel engines that BSAC is developing for power generation at the microscale will be discussed. The project goal is to develop electrical power output of 90milliwatts from the 2.4 mm engine. Prototype engine components have already been fabricated and these will be described. The integrated generator design concept utilizes a nickel-iron alloy electroplated in the engine rotor poles, so that the engine rotor also serves as the generator rotor.

  16. Rotary Power Transformer and Inverter Circuit

    Science.gov (United States)

    Mclyman, C. W. T.; Bridgeforth, A. O.

    1985-01-01

    Noise lower than with sliprings. Rotary transformer transfers electric power across rotary joint. No wearing contacts, no contact noise, and no contamination from lubricants or wear debris. Because additional inductor not required, size and complexity of circuit reduced considerably.

  17. Comparison of canal transportation and centering ability of rotary protaper, one shape system and wave one system using cone beam computed tomography: An in vitro study

    Science.gov (United States)

    Tambe, Varsha Harshal; Nagmode, Pradnya Sunil; Abraham, Sathish; Patait, Mahendra; Lahoti, Pratik Vinod; Jaju, Neha

    2014-01-01

    Aim: The aim of the present study was to compare the canal transportation and centering ability of Rotary ProTaper, One Shape and Wave One systems using cone beam computed tomography (CBCT) in curved root canals to find better instrumentation technique for maintaining root canal geometry. Materials and Methods: Total 30 freshly extracted premolars having curved root canals with at least 10 degrees of curvature were divided into three groups of 10 teeth each. All teeth were scanned by CBCT to determine the root canal shape before instrumentation. In Group 1, the canals were prepared with Rotary ProTaper files, in Group 2 the canals were prepared with One Shape files and in Group 3 canals were prepared with Wave One files. After preparation, post-instrumentation scan was performed. Pre-instrumentation and post-instrumentation images were obtained at three levels, 3 mm apical, 3 mm coronal and 8 mm apical above the apical foramen were compared using CBCT software. Amount of transportation and centering ability were assessed. The three groups were statistically compared with analysis of variance and Tukey honestly significant. Results: All instruments maintained the original canal curvature with significant differences between the different files. Data suggested that Wave One files presented the best outcomes for both the variables evaluated. Wave One files caused lesser transportation and remained better centered in the canal than One Shape and Rotary ProTaper files. Conclusion: The canal preparation with Wave One files showed lesser transportation and better centering ability than One Shape and ProTaper. PMID:25506145

  18. Developing Instruments to Assess and Compare the Quality of Engineering Education: The Case of China and Russia

    Science.gov (United States)

    Kardanova, Elena; Loyalka, Prashant; Chirikov, Igor; Liu, Lydia; Li, Guirong; Wang, Huan; Enchikova, Ekaterina; Shi, Henry; Johnson, Natalie

    2016-01-01

    Relatively little is known about differences in the quality of engineering education within and across countries because of the lack of valid instruments that allow for the assessment and comparison of engineering students' skill gains. The purpose of our study is to develop and validate instruments that can be used to compare student skill gains…

  19. How comparable are size-resolved particle number concentrations from different instruments?

    Science.gov (United States)

    Hornsby, K. E.; Pryor, S. C.

    2012-12-01

    The need for comparability of particle size resolved measurements originates from multiple drivers including: (i) Recent suggestions that air quality standards for particulate matter should migrate from being mass-based to incorporating number concentrations. This move would necessarily be predicated on measurement comparability which is absolutely critical to compliance determination. (ii) The need to quantify and diagnose causes of variability in nucleation and growth rates in nano-particle experiments conducted in different locations. (iii) Epidemiological research designed to identify key parameters in human health responses to fine particle exposure. Here we present results from a detailed controlled laboratory instrument inter-comparison experiment designed to investigate data comparability in the size range of 2.01-523.3 nm across a range of particle composition, modal diameter and absolute concentration. Particle size distributions were generated using a TSI model 3940 Aerosol Generation System (AGS) diluted using zero air, and sampled using four TSI Scanning Mobility Particle Spectrometer (SMPS) configurations and a TSI model 3091 Fast Mobility Particle Sizer (FMPS). The SMPS configurations used two Electrostatic Classifiers (EC) (model 3080) attached to either a Long DMA (LDMA) (model 3081) or a Nano DMA (NDMA) (model 3085) plumbed to either a TSI model 3025A Butanol Condensed Particle Counting (CPC) or a TSI model 3788 Water CPC. All four systems were run using both high and low flow conditions, and were operated with both the internal diffusion loss and multiple charge corrections turned on. The particle compositions tested were sodium chloride, ammonium nitrate and olive oil diluted in ethanol. Particles of all three were generated at three peak concentration levels (spanning the range observed at our experimental site), and three modal particle diameters. Experimental conditions were maintained for a period of 20 minutes to ensure experimental

  20. Effects of multiple root canal usage on the surface topography and fracture of two different Ni-Ti rotary file systems.

    Science.gov (United States)

    Kottoor, Jojo; Velmurugan, Natanasabapathy; Gopikrishna, Velayutham; Krithikadatta, Jogikalmat

    2013-01-01

    The purpose of this study was to evaluate the effect of multiple root canal usage on the surface topography and fracture of Twisted File (TF) and ProTaper (PT) rotary Ni-Ti file systems, using scanning electron microscope (SEM). Ten sets of PT and TF instruments were used to prepare the mesial canals of mandibular first molars. TF 25, 0.06 taper and PT F1 instruments were analyzed by SEM when new and thereafter every three root canal usages. This sequence was repeated for both the TF and PT groups until 12 uses. Two images of the instrument were recorded, one of the instrument tip and the other 5 mm from the tip, both at × 100 magnification. The sequential use was continued till the instrument fractured and the number of root canal usages for the file to fracture was noted. All fracture surfaces were examined under the SEM. Fresh TF instruments showed no surface wear when compared to PT instruments (P 0.05), while at the 9 th usage TF showed a steep increase in the spiral distortion score when compared to PT (P < 0.05). PT instruments fractured at a mean root canal usage of 17.4, while TF instruments showed a mean root canal usage of 11.8. Fractographically, all the TF instruments failed due to torsion, while all the PT instruments failed because of cyclic fatigue. PT instruments showed more resistance to fracture than TF instruments.

  1. Adiabatic Wankel type rotary engine

    Science.gov (United States)

    Kamo, R.; Badgley, P.; Doup, D.

    1988-01-01

    This SBIR Phase program accomplished the objective of advancing the technology of the Wankel type rotary engine for aircraft applications through the use of adiabatic engine technology. Based on the results of this program, technology is in place to provide a rotor and side and intermediate housings with thermal barrier coatings. A detailed cycle analysis of the NASA 1007R Direct Injection Stratified Charge (DISC) rotary engine was performed which concluded that applying thermal barrier coatings to the rotor should be successful and that it was unlikely that the rotor housing could be successfully run with thermal barrier coatings as the thermal stresses were extensive.

  2. Risk-free assets: Are they truly risk-free? A comparative study of South African rates and instruments

    Directory of Open Access Journals (Sweden)

    Oosthuizen, A.V.

    2013-10-01

    Full Text Available Determining the price of a financial instrument is something that happens every day in the financial markets. Every price starts off with a spot price adjusted for interest until maturity of the particular instrument. The interest is usually described as risk-free interest. The price so determined is the most basic price that an investor is willing to pay if not risk is involved. Risk-free assets, then, are securities of which the future rates of return are known with certainty. An exceptional degree of confidence in the issuer of the security brings about this certainty. Risk-free assets are normally in the fixed income securities (capital markets investment category or in the liquid money market instruments such as treasury bills, category. This study attempts to determine whether the risk-free rates used by treasury managers and traders in South Africa to formulate their bond yield curves and which are used in valuation models, may be deemed risk-free. The study specifies certain criteria that an asset must satisfy in order to be used as a risk-free asset. Short term and long term South African instruments are compared to the US counterpart instruments, to gain an understanding of the South African instruments relative to the US ones. The behaviour of the risk-free instruments used in South Africa is also compared to the FTSE/JSE All Share Index and gold spot prices, which are perceived to be a risky asset classes. To gain some understanding of the behaviour of these instruments, analyses were done from different angles. The standard deviations of the daily percentage changes of the R157 were significantly lower than that of the ALSI and the gold spot price change. Compared to the ALSI and gold spot price, therefore, the R157 may be deemed a “low risk” instrument. The JIBAR was even less volatile that the R157. Interestingly, the US instruments were substantially more risky than the SA instruments over the analysis period. Also the JIBAR

  3. Comparison of canal transportation and centering ability of hand Protaper files and rotary Protaper files by using micro computed tomography

    OpenAIRE

    Amit Gandhi; Taru Gandhi

    2011-01-01

    Introduction and objective: The aim of the present study was to compare root canal preparation with rotary ProTaper files and hand ProTaper files to find a better instrumentation technique for maintaining root canal geometry with the aid of computed tomography. Material and methods: Twenty curved root canals with at least 10 degree of curvature were divided into 2 groups of 10 teeth each. In group I the canals were prepared with hand ProTaper files and in group II the canals were prepared wit...

  4. Piezoelectric Versus Conventional Rotary Techniques for Impacted Third Molar Extraction: A Meta-analysis of Randomized Controlled Trials.

    Science.gov (United States)

    Jiang, Qian; Qiu, Yating; Yang, Chi; Yang, Jingyun; Chen, Minjie; Zhang, Zhiyuan

    2015-10-01

    Impacted third molars are frequently encountered in clinical work. Surgical removal of impacted third molars is often required to prevent clinical symptoms. Traditional rotary cutting instruments are potentially injurious, and piezosurgery, as a new osteotomy technique, has been introduced in oral and maxillofacial surgery. No consistent conclusion has been reached regarding whether this new technique is associated with fewer or less severe postoperative sequelae after third molar extraction.The aim of this study was to compare piezosurgery with rotary osteotomy techniques, with regard to surgery time and the severity of postoperative sequelae, including pain, swelling, and trismus.We conducted a systematic literature search in the Cochrane Library, PubMed, Embase, and Google Scholar.The eligibility criteria of this study included the following: the patients were clearly diagnosed as having impacted mandibular third molars; the patients underwent piezosurgery osteotomy, and in the control group rotary osteotomy techniques, for removing impacted third molars; the outcomes of interest include surgery time, trismus, swelling or pain; the studies are randomized controlled trials.We used random-effects models to calculate the difference in the outcomes, and the corresponding 95% confidence interval. We calculated the weighted mean difference if the trials used the same measurement, and a standardized mean difference if otherwise.A total of seven studies met the eligibility criteria and were included in our analysis. Compared with rotary osteotomy, patients undergoing piezosurgery experienced longer surgery time (mean difference 4.13 minutes, 95% confidence interval 2.75-5.52, P piezosurgery groups.The number of included randomized controlled trials and the sample size of each trial were relatively small, double blinding was not possible, and cost analysis was unavailable due to a lack of data.Our meta-analysis indicates that although patients undergoing piezosurgery

  5. Detailed characterizations of a Comparative Reactivity Method (CRM) instrument: experiments vs. modelling

    Science.gov (United States)

    Michoud, V.; Hansen, R. F.; Locoge, N.; Stevens, P. S.; Dusanter, S.

    2015-04-01

    The Hydroxyl radical (OH) is an important oxidant in the daytime troposphere that controls the lifetime of most trace gases, whose oxidation leads to the formation of harmful secondary pollutants such as ozone (O3) and Secondary Organic Aerosols (SOA). In spite of the importance of OH, uncertainties remain concerning its atmospheric budget and integrated measurements of the total sink of OH can help reducing these uncertainties. In this context, several methods have been developed to measure the first-order loss rate of ambient OH, called total OH reactivity. Among these techniques, the Comparative Reactivity Method (CRM) is promising and has already been widely used in the field and in atmospheric simulation chambers. This technique relies on monitoring competitive OH reactions between a reference molecule (pyrrole) and compounds present in ambient air inside a sampling reactor. However, artefacts and interferences exist for this method and a thorough characterization of the CRM technique is needed. In this study, we present a detailed characterization of a CRM instrument, assessing the corrections that need to be applied on ambient measurements. The main corrections are, in the order of their integration in the data processing: (1) a correction for a change in relative humidity between zero air and ambient air, (2) a correction for the formation of spurious OH when artificially produced HO2 react with NO in the sampling reactor, and (3) a correction for a deviation from pseudo first-order kinetics. The dependences of these artefacts to various measurable parameters, such as the pyrrole-to-OH ratio or the bimolecular reaction rate constants of ambient trace gases with OH are also studied. From these dependences, parameterizations are proposed to correct the OH reactivity measurements from the abovementioned artefacts. A comparison of experimental and simulation results is then discussed. The simulations were performed using a 0-D box model including either (1) a

  6. Comparation of instrumental and sensory methods in fermented milk beverages texture quality analysis

    Directory of Open Access Journals (Sweden)

    Jovica Hardi

    2001-04-01

    Full Text Available The texture of the curd of fermented dairy products is one of the primary factors of their overall quality. The flow properties of fermented dairy products have characteristic of thixotropic (pseudoplastic type of liquids. At the same time, these products are viscoelastic systems, i.e. they are capable of texture renewal after applied deformation. Complex analysis of some of the properties is essentional for the system description . The aim of the present work was to completely describe the texture of fermented milk beverages . Three basic parameters were taken into consideration: structure, hardness (consistency and stability of the curd. The description model of these three parameters was applied on the basis of the experimental results obteined. Results obtained by present model were compared with the results of sensory analysis. Influence of milk fat content and skimmed milk powder addition on acidophilus milk texture quality was also examined using this model. It was shawn that, by using this model – on the basis of instrumental and sensory analyses, a complete and objective determination of texture quality of the fermented milk beverages can be obtained. High degree of correlation between instrumental and sensory results (r =0.8975 is obtained results of this work indicated that both factors (milk fat content and skimmed milk powder addition had an influence on texture quality. Samples with higher milk fat content had a better texture properties in comparsion with low fat content samples. Texture of all examined samples was improved by increasing skimmed milk powder content. Optimal amounts of skimmed milk powder addition with regard to milk fat content, in milk, is determined using the proposed model.

  7. Development of a natural gas stratified charge rotary engine

    Energy Technology Data Exchange (ETDEWEB)

    Sierens, R.; Verdonck, W.

    1985-01-01

    A water model has been used to determine the positions of separate inlet ports for a natural gas, stratified charge rotary engine. The flow inside the combustion chamber (mainly during the induction period) has been registered by a film camera. From these tests the best locations of the inlet ports have been obtained, a prototype of this engine has been built by Audi NSU and tested in the laboratories of the university of Gent. The results of these tests, for different stratification configurations, are given. These results are comparable with the best results obtained by Audi NSU for a homogeneous natural gas rotary engine.

  8. Rotary condenser for SC2

    CERN Multimedia

    1975-01-01

    During 1975 the SC2 performance was improved among other things by redesigning some of the elements of the ROTCO (Annual Report 1975, p. 55). The photo shows an interior wiew of the housing of the rotary condenser and of the sixteen sets of shaped stator blades.

  9. Design of angular position detector for rotary stepping motor of CEDM

    International Nuclear Information System (INIS)

    Park, Seok Ha; Kim, Jong In; Kim, Ji Ho; Huh, Hyung; Yu, Je Yong

    2000-11-01

    The position of control rod must be detected continuously to control CEDM control rod used in SMART. The up-and-down movement of control rod can be detected approximately by using a position indicator, but an additionary sensor should be required because the accuracy of it is low. And because the rotary stepping motor for SMART CEDM is to work at harsh conditions of high temperature, pressure and radiation, it is difficult to select an adequate sensor from commercially available products. Therefore, a sensor to monitor the position of control rod by detecting the position of rotary angle for stepping motor should studied. This paper analyzes and compares the techniques of Synchro, Resolver, and Magnesyn being used as a rotary angle detector for stepping motor. The rotary angle detector by using our unique concept is designed on the basis of upper work. The prototype of rotary angle detector is produced and the results of test and valuation is presented

  10. A comparative review of measurement instruments to inform and evaluate effectiveness of disability inclusive development.

    Science.gov (United States)

    Goujon, Nicolas; Devine, Alexandra; Baker, Sally M; Sprunt, Beth; Edmonds, Tanya J; Booth, Jennifer K; Keeffe, Jill E

    2014-01-01

    A review of existing measurement instruments was conducted to examine their suitability to measure disability prevalence and assess quality of life, protection of disability rights and community participation by people with disabilities, specifically within the context of development programs in low and middle-income countries. From a search of PubMed and the grey literature, potentially relevant measurement instruments were identified and examined for their content and psychometric properties, where possible. Criteria for inclusion were: based on the WHO's International Classification of Functioning Disability and Health (ICF), used quantitative methods, suitable for population-based studies of disability inclusive development in English and published after 1990. Characteristics of existing instruments were analysed according to components of the ICF and quality of life domains. Ten instruments were identified and reviewed according to the criteria listed above. Each version of instruments was analysed separately. Only three instruments included a component on quality of life. Domains from the ICF that were addressed by some but not all instruments included the environment, technology and communication. The measurement instruments reviewed covered the range of elements required to measure disability-inclusion within development contexts. However no single measurement instrument has the capacity to measure both disability prevalence and changes in quality of life according to contemporary disability paradigms. The review of measurement instruments supports the need for developing an instrument specifically intended to measure disability inclusive practice within development programs. Implications for Rehabilitation Surveys and tools are needed to plan disability inclusive development. Existing measurement tools to determine prevalence of disability, wellbeing, rights and access to the community were reviewed. No single validated tool exists for population

  11. Designing Chemistry Practice Exams for Enhanced Benefits: An Instrument for Comparing Performance and Mental Effort Measures

    Science.gov (United States)

    Knaus, Karen J.; Murphy, Kristen L.; Holme, Thomas A.

    2009-01-01

    The design and use of a chemistry practice exam instrument that includes a measure for student mental effort is described in this paper. Use of such an instrument can beneficial to chemistry students and chemistry educators as well as chemical education researchers from both a content and cognitive science perspective. The method for calculating…

  12. Endodontic retreatment: clinical comparison of reciprocating systems versus rotary system in disinfecting root canals.

    Science.gov (United States)

    Martinho, Frederico C; Freitas, Lilian F; Nascimento, Gustavo G; Fernandes, Aleteia M; Leite, Fabio R M; Gomes, Ana P M; Camões, Izabel C G

    2015-07-01

    This clinical study was conducted to compare the effectiveness of single-file reciprocating systems and rotary systems in removing endotoxins and cultivable bacteria in endodontic retreatment. Thirty endodontically treated teeth with post-treatment apical periodontitis were selected. The specimens were divided into three groups according to the system used: WaveOne (n = 10), Reciproc instrument (n = 10), and ProTaper Universal Retreatment system (n = 10). Samples were collected before and after chemomechanical preparation. The irrigation was performed by using 2.5% sodium hypochlorite. A chromogenic limulus amebocyte lysate assay test was used to quantify endotoxins. Culture techniques were used to determine bacterial colony-forming unit counts. At baseline, endotoxins and cultivable bacteria were recovered from 100% of the root canal samples in a median value of 5.84 EU/mL and 4.98 × 10(3) CFU/mL, respectively. After CMP, no differences were found in the median percentage values of endotoxin reduction achieved with reciprocating systems-WaveOne [94.11%] and Reciproc [93.29%] and with rotary systems-ProTaper [94.98%] (P > 0.05). Both single-file reciprocating systems [WaveOne (98.27%) and Reciproc (99.54%)] and rotary system [ProTaper (98.73%)] were effective in reducing bacterial load (P > 0.05). Moreover, no differences were found among the systems tested. The Reciproc and WaveOne reciprocating systems were as effective as the ProTaper system for removal of endotoxins and bacteria in endodontic retreatment. All systems tested were effective to remove cultivable bacteria and endotoxin in endodontic retreatment. As no differences among systems were observed, it is possible to suggest that clinicians should choose the preferred technique to perform endodontic.

  13. Stratified charge rotary engine critical technology enablement. Volume 2: Appendixes

    Science.gov (United States)

    Irion, C. E.; Mount, R. E.

    1992-01-01

    This second volume of appendixes is a companion to Volume 1 of this report which summarizes results of a critical technology enablement effort with the stratified charge rotary engine (SCRE) focusing on a power section of 0.67 liters (40 cu. in.) per rotor in single and two rotor versions. The work is a continuation of prior NASA Contracts NAS3-23056 and NAS3-24628. Technical objectives are multi-fuel capability, including civil and military jet fuel and DF-2, fuel efficiency of 0.355 Lbs/BHP-Hr. at best cruise condition above 50 percent power, altitude capability of up to 10Km (33,000 ft.) cruise, 2000 hour TBO and reduced coolant heat rejection. Critical technologies for SCRE's that have the potential for competitive performance and cost in a representative light-aircraft environment were examined. Objectives were: the development and utilization of advanced analytical tools, i.e. higher speed and enhanced three dimensional combustion modeling; identification of critical technologies; development of improved instrumentation; and to isolate and quantitatively identify the contribution to performance and efficiency of critical components or subsystems. A family of four-stage third-order explicit Runge-Kutta schemes is derived that required only two locations and has desirable stability characteristics. Error control is achieved by embedding a second-order scheme within the four-stage procedure. Certain schemes are identified that are as efficient and accurate as conventional embedded schemes of comparable order and require fewer storage locations.

  14. Rotary and radial forcing effects on center-of-mass locomotion dynamics

    International Nuclear Information System (INIS)

    Shen, Z H; Larson, P L; Seipel, J E

    2014-01-01

    Rotary and radial forcing are two common actuation methods for legged robots. However, these two orthogonal methods of center-of-mass (CoM) forcing have not been compared as potentially alternative strategies of actuation. In this paper, we compare the CoM stability and energetics of running with rotary and radial actuation through the simulation of two models: the rotary-forced spring-loaded inverted pendulum (rotary-forced-SLIP), and the radially-forced-SLIP. We model both radial and rotary actuation in the simplest way, applying them as a constant force during the stance portion of the gait. A simple application of constant rotary forcing throughout stance is capable of producing fully-asymptotically stable motion; however, a similarly constant application of radial forcing throughout the stance is not capable of producing stable solutions. We then allow both the applied rotary and radial forcing functions to turn on or off based on the occurrence of the mid-stance event, which breaks the symmetry of actuation during stance towards a net forward propulsion. We find that both a rotary force applied in the first half of stance and a radial force applied in the second half of stance, are capable of stabilizing running. Interestingly, these two forcing methods improve the motion stability in different ways. Rotary forcing first reduces then greatly increases the size of the stable parameter region when gradually increased. Radial forcing expands the stable parameter region, but only in a moderate way. Also, it is found that parameter region stabilized by rotary and radial forcing are largely complementary. Overall, rotary forcing can better stabilize running for both constant and event-based forcing functions that were attempted. This indicates that rotary forcing has an inherent capability of stabilizing running, even when minimal time-or-event-or-state feedback is present. Radial forcing, however, tends to be more energy efficient when compared to rotary forcing

  15. Rotary and radial forcing effects on center-of-mass locomotion dynamics.

    Science.gov (United States)

    Shen, Z H; Larson, P L; Seipel, J E

    2014-09-01

    Rotary and radial forcing are two common actuation methods for legged robots. However, these two orthogonal methods of center-of-mass (CoM) forcing have not been compared as potentially alternative strategies of actuation. In this paper, we compare the CoM stability and energetics of running with rotary and radial actuation through the simulation of two models: the rotary-forced spring-loaded inverted pendulum (rotary-forced-SLIP), and the radially-forced-SLIP. We model both radial and rotary actuation in the simplest way, applying them as a constant force during the stance portion of the gait. A simple application of constant rotary forcing throughout stance is capable of producing fully-asymptotically stable motion; however, a similarly constant application of radial forcing throughout the stance is not capable of producing stable solutions. We then allow both the applied rotary and radial forcing functions to turn on or off based on the occurrence of the mid-stance event, which breaks the symmetry of actuation during stance towards a net forward propulsion. We find that both a rotary force applied in the first half of stance and a radial force applied in the second half of stance, are capable of stabilizing running. Interestingly, these two forcing methods improve the motion stability in different ways. Rotary forcing first reduces then greatly increases the size of the stable parameter region when gradually increased. Radial forcing expands the stable parameter region, but only in a moderate way. Also, it is found that parameter region stabilized by rotary and radial forcing are largely complementary. Overall, rotary forcing can better stabilize running for both constant and event-based forcing functions that were attempted. This indicates that rotary forcing has an inherent capability of stabilizing running, even when minimal time-or-event-or-state feedback is present. Radial forcing, however, tends to be more energy efficient when compared to rotary forcing

  16. A comparative analysis of the effects of economic policy instruments in promoting environmentally sustainable transport

    DEFF Research Database (Denmark)

    Elvik, Rune; Ramjerdi, Farideh

    2014-01-01

    ; (3) Toll schemes; (4) Reward systems giving incentives to reduce driving or change driver behaviour. The effects of these policy instruments are stated in terms of elasticities. All four economic policy instruments have negative elasticities, which means that they do promote environmentally...... sustainable transport. Long-term elasticities tend to be larger than short term elasticities. The long-term elasticities of reward systems are unknown. (C) 2014 Elsevier Ltd. All rights reserved....

  17. A quantitative analysis of rotary, ultrasonic and manual techniques to treat proximally flattened root canals

    Directory of Open Access Journals (Sweden)

    Fabiana Soares Grecca

    2007-04-01

    Full Text Available OBJECTIVE: The efficiency of rotary, manual and ultrasonic root canal instrumentation techniques was investigated in proximally flattened root canals. MATERIAL AND METHODS: Forty human mandibular left and right central incisors, lateral incisors and premolars were used. The pulp tissue was removed and the root canals were filled with red die. Teeth were instrumented using three techniques: (i K3 and ProTaper rotary systems; (ii ultrasonic crown-down technique; and (iii progressive manual technique. Roots were bisected longitudinally in a buccolingual direction. The instrumented canal walls were digitally captured and the images obtained were analyzed using the Sigma Scan software. Canal walls were evaluated for total canal wall area versus non-instrumented area on which dye remained. RESULTS: No statistically significant difference was found between the instrumentation techniques studied (p<0.05. CONCLUSION: The findings of this study showed that no instrumentation technique was 100% efficient to remove the dye.

  18. Linear rotary optical delay lines

    Science.gov (United States)

    Guerboukha, Hichem; Qu, Hang; Skorobogatiy, Maksim

    2016-03-01

    We present a semi-analytical solution for the design of a high-speed rotary optical delay line that use a combination of two rotating curvilinear reflectors. We demonstrate that it is possible to design an infinite variety of the optical delay lines featuring linear dependence of the optical delay on the rotation angle. This is achieved via shape optimization of the rotating reflector surfaces. Moreover, a convenient spatial separation of the incoming and outgoing beams is possible. For the sake of example, we present blades that fit into a circle of 10cm diameter. Finally, a prototype of a rotary delay line is fabricated using CNC machining, and its optical properties are characterized.

  19. Comparative Analysis of Various Aspects of Plateletpheresis on the Fenwal Amicus and Fresenius COM.TEC Cell Separator Instruments.

    Science.gov (United States)

    Philip, Joseph; Biswas, Amit Kumar; Chatterjee, Tathagata; Mallhi, Rajiv Singh

    2014-01-01

    To compare the Fenwal Amicus and the Fresenius COM.TEC apheresis instruments regarding donor peripheral blood parameters, operational variables of the instruments, and quality control parameters of the product obtained. We performed 100 platelet collections from 100 voluntary donors using the 2 studied devices. We measured platelet count using an automated analyzer and analyzed the activation statuses using a flow cytometer. The median time needed to perform the procedures was significantly longer with the COM.TEC. However, the product we obtained using the Amicus instrument showed higher degrees of platelet-activation. All products we obtained with both instruments had white blood cell counts of less than 5 × 10(6) per bag. We observed no statistical difference regarding collection efficiency and collection rates between the devices. Both instruments collected platelets efficiently, with minimal donor discomfort. Compared with the COM.TEC instrument, the Amicus reached the platelet target yield more quickly; however, it displayed an increase in platelet activation. Copyright© by the American Society for Clinical Pathology (ASCP).

  20. Feeding device for rotary retorts

    Energy Technology Data Exchange (ETDEWEB)

    Hutchins, T W.S.

    1923-04-25

    A horizontal rotary retort is heated externally with a feeding-worm or the like for distilling coal, oil shale, etc. It is characterized in that the shaft of the feeder moves adjustably lengthwise, so that, under the hopper more or less of the worm comes for action on the feed, so that the hopper is withdrawn through the retort while it projects into the retort and is secured in a position against the rotation.

  1. Rotary piston blood pumps: past developments and future potential of a unique pump type.

    Science.gov (United States)

    Wappenschmidt, Johannes; Autschbach, Rüdiger; Steinseifer, Ulrich; Schmitz-Rode, Thomas; Margreiter, Raimund; Klima, Günter; Goetzenich, Andreas

    2016-08-01

    The design of implantable blood pumps is either based on displacement pumps with membranes or rotary pumps. Both pump types have limitations to meet the clinical requirements. Rotary piston blood pumps have the potential to overcome these limitations and to merge the benefits. Compared to membrane pumps, they are smaller and with no need for wear-affected membranes and valves. Compared to rotary pumps, the blood flow is pulsatile instead of a non-physiological continuous flow. Furthermore, the risk of flow-induced blood damage and platelet activation may be reduced due to low shear stress to the blood. The past developments of rotary piston blood pumps are summarized and the main problem for long-term application is identified: insufficient seals. A new approach with seal-less drives is proposed and current research on a simplified rotary piston design is presented. Expert commentary: The development of blood pumps focuses mainly on the improvement of rotary pumps. However, medical complications indicate that inherent limitations of this pump type remain and restrict the next substantial step forward in the therapy of heart failure patients. Thus, research on different pump types is reasonable. If the development of reliable drives and bearings succeeds, rotary piston blood pumps become a promising alternative.

  2. Capacity control of rotary vane apparatus

    International Nuclear Information System (INIS)

    Roberts, R. W.

    1985-01-01

    A capacity control arrangement for a rotary vane fluid displacement apparatus, such as a rotary vane compressor, having a vane retaining means that normally engages and retains the vanes in their retracted or nonworking position within the rotor defined guide slits of such rotary vane compressor. The retaining means are actuated to the vane-disengaged position by hydraulic control fluid which is communicated to the retaining means in response to an external parameter sensed by a control means

  3. Modificações da curvatura de canais simulados após emprego de instrumentos rotatórios Curvature modification of simulated root canals after use of rotary instruments

    Directory of Open Access Journals (Sweden)

    Suely Maria Santos LAMARÃO

    1999-01-01

    Full Text Available É a partir da instrumentação que o canal radicular adquire a forma necessária à adaptação perfeita do material obturador. Durante essa fase, é necessário que ocorra uma interação entre instrumento e canal radicular com vistas a reduzir o número de alterações decorrentes desse passo improcedente. Neste estudo, procurou-se observar a ação de dois tipos de instrumentos endodônticos mecânico-rotatórios: as limas Quantec series 2000 tipo SC, com ponta cortante, e tipo LX, com ponta embotada, na instrumentação de canais simulados com curvaturas entre 20 e 35 graus, valendo-se da técnica Quantec Graduating TapersTM. Os resultados evidenciaram que a média de alteração da curvatura dos canais do Grupo I, que foram instrumentados com limas SC, foi 2,15%; para os canais do Grupo II, instrumentados com limas LX, foi de 2,61%. Embora tenha-se verificado que os canais do Grupo I apresentaram menor percentagem de alteração da curvatura, o teste estatístico pertinente de Mann-Whitney demonstrou não existir diferença significante para ± 5% entre os dois grupos experimentais.After instrumentation, the root canal acquires the necessary shape for a perfect adaptation of filling material. During this phase cutting end and LX type an interaction between instrument and root canal is necessary in order to reduce alterations that could occur at this point. This study evaluated the action of two mechanical-rotatory endodontic instruments, Quantec files 2000 serie type SC with blunt end, during the instrumentation of simulated canals curved between 20 and 35 degrees, using quantec graduating tapers. Results showed that the mean curvature alteration of group I canals that were instrumented with SC files, was 2,15%, and for group II instrumented with LX files, was 2,61%. Furthermore group I canals showed lower percentage of curvature alteration. Mann-Whitney tests showed no significant statistical difference at 5% between experimental groups.

  4. Lignite chemical conversion in an indirect heat rotary kiln gasifier

    Directory of Open Access Journals (Sweden)

    Hatzilyberis Kostas S.

    2006-01-01

    Full Text Available The results on the gasification of Greek lignite using two indirect heat (allothermal pilot rotary kiln gasifiers are reported in the present work. The development of this new reactor-gasifier concept intended for solid fuels chemical conversion exploits data and experience gained from the following two pilot plants. The first unit A (about 100 kg/h raw lignite demonstrated the production of a medium heating value gas (12-13 MJ/Nm3 with quite high DAF (dry ash free coal conversions, in an indirect heat rotary gasifier under mild temperature and pressure conditions. The second unit B is a small pilot size unit (about 10 kg/h raw lignite comprises an electrically heated rotary kiln, is an operation flexible and exhibits effective phase mixing and enhanced heat transfer characteristics. Greek lignite pyrolysis and gasification data were produced from experiments performed with pilot plant B and the results are compared with those of a theoretical model. The model assumes a scheme of three consecutive-partly parallel processes (i. e. drying, pyrolysis, and gasification and predicts DAF lignite conversion and gas composition in relatively good agreement with the pertinent experimental data typical of the rotary kiln gasifier performance. Pilot plant B is currently being employed in lime-enhanced gasification studies aiming at the production of hydrogen enriched synthesis gas. Presented herein are two typical gas compositions obtain from lignite gasification runs in the presence or not of lime. .

  5. Convective heat transfer analysis in aggregates rotary drum reactor

    International Nuclear Information System (INIS)

    Le Guen, Laurédan; Huchet, Florian; Dumoulin, Jean; Baudru, Yvan; Tamagny, Philippe

    2013-01-01

    Heat transport characterisation inside rotary drum dryer has a considerable importance linked to many industrial applications. The present paper deals with the heat transfer analysis from experimental apparatus installed in a large-scale rotary drum reactor applied to the asphalt materials production. The equipment including in-situ thermal probes and external visualization by mean of infrared thermography gives rise to the longitudinal evaluation of inner and external temperatures. The assessment of the heat transfer coefficients by an inverse methodology is resolved in order to accomplish a fin analysis of the convective mechanism inside baffled (or flights) rotary drum. The results are discussed and compared with major results of the literature. -- Highlights: ► A thermal and flow experimentation is performed on a large-scale rotary drum. ► Four working points is chosen in the frame of asphalt materials production. ► Evaluation of the convective transfer mechanisms is calculated by inverse method. ► The drying stage is performed in the combustion area. ► Wall/aggregates heat exchanges have a major contribution in the heating stage

  6. Canal Centring Ability of ProTaper and Mtwo Rotary Systems in Curved Canals

    Directory of Open Access Journals (Sweden)

    Turkaydin Dilek Erbay

    2014-07-01

    Full Text Available The purpose of this investigation was to compare centring ratio of ProTaper and Mtwo rotary systems. 60 mandibular molar teeth which had 25, 30 and 35 degree curvature in mesio-buccal root canal were used. Group 1 had 25°, Group 2 had 30°, and Group 3 had 35° curvatures. The roots were sectioned horizontally at 2 mm away from the apex. The apical region was then observed under a stereo-microscope. In each group, teeth were instrumented using ProTaper and Mtwo systems. After canal preparation, digital images of apical part of canals were taken. These images were then superimposed by using Adobe Photoshop CS2 programme. The data were analyzed using ANOVA and Student’s t-test.

  7. Comparing instrumental and deliberative paradigms underpinning the assessment of social values for cultural ecosystem services

    DEFF Research Database (Denmark)

    Raymond, Christopher M.; Kenter, Jasper O.; Plieninger, Tobias

    2014-01-01

    Despite rapid advancements in the development of non-monetary techniques for the assessment of social values for ecosystem services, little research attention has been devoted to the evaluation of their underpinning paradigms. This study evaluates two contrasting paradigms for the assessment...... of social values in non-monetary terms: an instrumental paradigm involving an objective assessment of the distribution, type and/or intensity of values that individuals assign to the current state of ecosystems and a deliberative paradigm involving the exploration of desired end states through group...... discussion. We present and then justify through case examples two approaches for assessing social values for ecosystem services using the instrumental paradigm and two approaches using the deliberative paradigm. Each approach makes different assumptions about: the underlying rationale for values assessment...

  8. Instrumentation for comparing night sky quality and atmospheric conditions of CTA site candidates

    Czech Academy of Sciences Publication Activity Database

    Fruck, C.; Gaug, M.; Ernenwein, J.-P.; Mandát, Dušan; Schweizer, T.; Häfner, D.; Bulik, T.; Cieslar, M.; Costantini, H.; Dominik, M.; Ebr, Jan; Garczarczyk, M.; Lorentz, E.; Pareschi, I.; Pech, Miroslav; Puerto-Giménez, I.; Teshima, M.

    2015-01-01

    Roč. 10, Apr (2015), P04012 ISSN 1748-0221 R&D Projects: GA MŠk(CZ) 7AMB12AR013; GA MŠk LE13012; GA MŠk LG14019 Institutional support: RVO:68378271 Keywords : large detector systems for particle and astroparticle physics * gamma telescopes * instrument optimisation * gamma detectors Subject RIV: BF - Elementary Particles and High Energy Physics Impact factor: 1.310, year: 2015

  9. Precision of GNSS instruments by static method comparing in real time

    Directory of Open Access Journals (Sweden)

    Slavomír Labant

    2009-09-01

    Full Text Available Tablet paper describes comparison of measuring accuracy two apparatus from the firm Leica. One of them recieve signals onlyfrom GPS satelites and another instrument is working with GPS and also with GLONASS satelites. Measuring is carry out by RTK staticmethod with 2 minutes observations. Measurement processing is separated to X, Y (position and h (heigh. Adjustment of directobservations is used as a adjusting method.

  10. 21 CFR 872.4840 - Rotary scaler.

    Science.gov (United States)

    2010-04-01

    ... DENTAL DEVICES Surgical Devices § 872.4840 Rotary scaler. (a) Identification. A rotary scaler is an abrasive device intended to be attached to a powered handpiece to remove calculus deposits from teeth during dental cleaning and periodontal (gum) therapy. (b) Classification. Class II. ...

  11. Rotary-atomizer electric power generator

    NARCIS (Netherlands)

    Nguyen, Trieu; Tran, Tuan; de Boer, Hans L.; van den Berg, Albert; Eijkel, Jan C.T.

    2015-01-01

    We report experimental and theoretical results on a ballistic energy-conversion method based on a rotary atomizer working with a droplet acceleration-deceleration cycle. In a rotary atomizer, liquid is fed onto the center of a rotating flat surface, where it spreads out under the action of the

  12. Split Coil Forms for Rotary Transformers

    Science.gov (United States)

    Mclyman, C. W. T.

    1982-01-01

    Split cores for rotor and stator windings of rotary transformer mounted around their respective coils (which are in bobbins) and cemented together. This arrangement simplifies winding of stator coil to go in a slot in inner diameter of stator coil. One practical application of rotary transformers fabricated according to this technique is for centrifuges, in which conventional sliprings are of uncertain reliability.

  13. A Comparative Analysis of Policy Instruments Promoting Green Electricity under Uncertainty

    International Nuclear Information System (INIS)

    Carlen, Bjoern

    2006-07-01

    The paper presented here studies, in a more systematic way than previous literature, the implications uncertainty regarding i.a. future production costs of green as well as conventional electricity has on the optimal choice of instrument to promote production of green electricity. The objective is to identify relevant effects the regulator need to assess before being able to make an informed choice. The instruments studied are (i) a feed-in tariff, i.e., an obligation for retailers of electricity to buy whatever quantity of green electricity that is supplied at a price determined by the regulator, (ii) a so-called environmebonus; , i.e., a fixed premium to producers of green electricity over and above the market price on electricity, (iii) an obligation for the retailers to procure a certain quantity of green electricity, and (iv) green electricity certificates, i.e., an obligation for retailers to purchase green electricity in an amount equal to a given share of their total electricity sale. It has been suggested, in the literature on instruments to promote production of green electricity, that price-based policies (e.g., fixed-in tariffs) would be superior to quantity-based policies (e.g., an obligation on retailers of electricity to procure a given amount of green electricity). The stated reason is that quantity-based policies tend to induce too much (little) green electricity whenever production costs turn out to be higher (lower) than expected. However, price-based policies, on the other hand, induces too little (much) green electricity, and, as shown here quantity-based policies can be designed in ways making them superior to a fixed feed-in tariff in the sense of yielding a smaller expected efficiency loss. It is also shown here that green electricity certificate system and systems with so-called environmental bonuses are more complicated policy instruments than so far has been recognized. If future electricity prices are highly uncertain, an environmental

  14. Artificial weathering of oils by rotary evaporator

    International Nuclear Information System (INIS)

    Fieldhouse, B.; Hollebone, B.P.; Singh, N.R.; Tong, T.S.; Mullin, J.

    2009-01-01

    Oil weathering has a considerable affect on the behaviour, impact and ultimate fate of an oil spill. As such, efforts have been made to study weathering as a whole using bench-scale procedures. The studies are generally divided into individual processes where the effect of other major processes are introduce as an amended sample input rather than a concurrent process. The weathering process that has the greatest effect immediately following an oil spill is evaporation, particularly for lighter oils. The rotary evaporator apparatus offers a convenient means of producing artificially weathered oil for laboratory studies. This paper reported on a study that examined the representativeness of samples obtained by this method compared to pan evaporation and the impact of changes to the apparatus or method parameters on sample chemistry. Experiments were performed on Alberta Sweet Mixed Blend no. 5 in a rotary evaporator under varying conditions of temperature and air flow at ambient pressure using 2 apparatus. The rate of mass loss increased with temperature and air flow rate as expected, but the quantitative relationships could not be defined from the data due to contributions by other uncontrolled factors. It was concluded that the rotary evaporator is not suited for evaporation rate studies, but rather for producing samples suitable for use in other studies. Chemical analysis showed that the relative abundance distributions of target n-alkane hydrocarbons varied with the degree of weathering of an oil in a consistent manner at ambient pressure, regardless of the temperature, rate of air exchange or other factors related to the apparatus and procedure. The composition of the artificially weathered oil was also consistent with that from an open pan simulation of a weathered oil slick. Loss of water content varied with the conditions of evaporation because of the differential rates of evaporation due to relative humidity considerations. It was concluded that weathering

  15. Testing Of The Dual Rotary Filter System

    International Nuclear Information System (INIS)

    Herman, D.; Fowley, M.; Stefanko, D.

    2011-01-01

    The Savannah River National Laboratory (SRNL) installed and tested two hydraulically connected SpinTek rotary microfilter (RMF) units to determine the behavior of a multiple filter system. Both units were successfully controlled by a control scheme written in DELTA-V architecture by Savannah River Remediation (SRR) Process Control Engineering personnel. The control system was tuned to provide satisfactory response to changing conditions during the operation of the multi-filter system. Stability was maintained through the startup and shutdown of one of the filter units while the second was still in operation. The installation configuration originally proposed by the Small Colum Ion Exchange (SCIX) project of independent filter and motor mountings may be susceptible to vibration. Significant stiffening of the filter and motor mounts was required to minimize the vibration. Alignment of the motor to the filter was a challenge in this test configuration. The deployment configuration must be easy to manipulate and allow for fine adjustment. An analysis of the vibration signature of the test system identified critical speeds. Whether it corresponds to the resonance frequency of a rotor radial vibration mode that was excited by rotor unbalance is uncertain based upon the measurements. A relative motion series should be completed on the filter with the final shaft configuration to determine if the resonances exist in the final filter design. The instrumentation selected for deployment, including the concentrate discharge control valve and flow meters, performed well. Automation of the valve control integrated well with the control scheme and when used in concert with the other control variables, allowed automated control of the dual RMF system. The one area of concern with the instrumentation was the condition resulting when the filtrate flow meter operated with less than three gpm. This low flow was at the lower range of performance for the flow meter. This should not be

  16. TESTING OF THE DUAL ROTARY FILTER SYSTEM

    Energy Technology Data Exchange (ETDEWEB)

    Herman, D.; Fowley, M.; Stefanko, D.

    2011-08-29

    The Savannah River National Laboratory (SRNL) installed and tested two hydraulically connected SpinTek rotary microfilter (RMF) units to determine the behavior of a multiple filter system. Both units were successfully controlled by a control scheme written in DELTA-V architecture by Savannah River Remediation (SRR) Process Control Engineering personnel. The control system was tuned to provide satisfactory response to changing conditions during the operation of the multi-filter system. Stability was maintained through the startup and shutdown of one of the filter units while the second was still in operation. The installation configuration originally proposed by the Small Colum Ion Exchange (SCIX) project of independent filter and motor mountings may be susceptible to vibration. Significant stiffening of the filter and motor mounts was required to minimize the vibration. Alignment of the motor to the filter was a challenge in this test configuration. The deployment configuration must be easy to manipulate and allow for fine adjustment. An analysis of the vibration signature of the test system identified critical speeds. Whether it corresponds to the resonance frequency of a rotor radial vibration mode that was excited by rotor unbalance is uncertain based upon the measurements. A relative motion series should be completed on the filter with the final shaft configuration to determine if the resonances exist in the final filter design. The instrumentation selected for deployment, including the concentrate discharge control valve and flow meters, performed well. Automation of the valve control integrated well with the control scheme and when used in concert with the other control variables, allowed automated control of the dual RMF system. The one area of concern with the instrumentation was the condition resulting when the filtrate flow meter operated with less than three gpm. This low flow was at the lower range of performance for the flow meter. This should not be

  17. Efficacy of D-RaCe and ProTaper Universal Retreatment NiTi instruments and hand files in removing gutta-percha from curved root canals - a micro-computed tomography study.

    Science.gov (United States)

    Rödig, T; Hausdörfer, T; Konietschke, F; Dullin, C; Hahn, W; Hülsmann, M

    2012-06-01

    To compare the efficacy of two rotary NiTi retreatment systems and Hedström files in removing filling material from curved root canals. Curved root canals of 57 extracted teeth were prepared using FlexMaster instruments and filled with gutta-percha and AH Plus. After determination of root canal curvatures and radii in two directions, the teeth were assigned to three identical groups (n = 19). The root fillings were removed with D-RaCe instruments, ProTaper Universal Retreatment instruments or Hedström files. Pre- and postoperative micro-CT imaging was used to assess the percentage of residual filling material as well as the amount of dentine removal. Working time and procedural errors were recorded. Data were analysed using analysis of covariance and analysis of variance procedures. D-RaCe instruments were significantly more effective than ProTaper Universal Retreatment instruments and Hedström files (P ProTaper group, four instrument fractures and one lateral perforation were observed. Five instrument fractures were recorded for D-RaCe. D-RaCe instruments were associated with significantly less residual filling material than ProTaper Universal Retreatment instruments and hand files. Hedström files removed significantly less dentine than both rotary NiTi systems. Retreatment with rotary NiTi systems resulted in a high incidence of procedural errors. © 2012 International Endodontic Journal.

  18. A Comparative study on the Role of Energy Efficiency in Urban Planning Instruments of Iran and Germany

    Directory of Open Access Journals (Sweden)

    Mahta Mirmoghtadaee

    2015-12-01

    Full Text Available In recent years energy efficiency in different levels become of prime importance. Studies have been shown that urban planning can play a critical role in this area. At the same time in oil-producing countries like Iran, energy efficiency has not been considered as a national priority. However, in recent years with increase in the population growth, rapid urbanization and acceleration of environmental degradation, the issue is gaining more importance. Iran has adopted its first national building code on energy efficiency in 90’s. However, as the country lacks a hierarchical energy planning system, its achievements were below the expectations. To improve the situation, it is important to study the experiences of other countries. Germany with a solid and successful energy planning in different scales can be considered as one of the pioneering countries, and its programs could be used as a guideline to achieve similar goals in other countries. Recently the German government has adopted a highly ambitious energy program, called “Energy transition” (Energiewende. The program will affect all planning instruments and ordinances in the country. As a comprehensive and upper level plan, "Energy transition" can be studied form different viewpoints. In the current study, its influence on urban planning instruments will be the main focus. The main objective is to compare the role of energy in urban planning instruments of Iran and Germany, and to develop some solutions and strategies to be considered in Iran. The first step in this study is the introduction of urban planning systems and instruments in the two countries, then the role of energy in each country will be introduced and with an analytical review, some suggestion for Iranian planning instruments will be made. Using comparative study as the research methodology, the study will focus on "comprehensive plan" and "detailed plan" as two main urban planning instruments in Iran, and "binding land

  19. [Comparison of effectiveness and safety between Twisted File technique and ProTaper Universal rotary full sequence based on micro-computed tomography].

    Science.gov (United States)

    Chen, Xiao-bo; Chen, Chen; Liang, Yu-hong

    2016-02-18

    To evaluate the efficacy and security of two type of rotary nickel titanium system (Twisted File and ProTaper Universal) for root canal preparation based on micro-computed tomography(micro-CT). Twenty extracted molars (including 62 canals) were divided into two experimental groups and were respectively instrumented using Twisted File rotary nickel titanium system (TF) and ProTaper Universal rotary nickel titanium system (PU) to #25/0.08 following recommended protocol. Time for root canal instrumentation (accumulation of time for every single file) was recorded. The 0-3 mm root surface from apex was observed under an optical stereomicroscope at 25 × magnification. The presence of crack line was noted. The root canals were scanned with micro-CT before and after root canal preparation. Three-dimensional shape images of canals were reconstructed, calculated and evaluated. The amount of canal central transportation of the two groups was calculated and compared. The shorter preparation time [(0.53 ± 0.14) min] was observed in TF group, while the preparation time of PU group was (2.06 ± 0.39) min (Pvs. (0.097 ± 0.084) mm, P<0.05]. No instrument separation was observed in both the groups. Cracks were not found in both the groups either based in micro-CT images or observation under an optical stereomicroscope at 25 × magnification. Compared with ProTaper Universal, Twisted File took less time in root canal preparation and exhibited better shaping ability, and less canal transportation.

  20. Comparative effectiveness of manipulation, mobilisation and the Activator instrument in treatment of non-specific neck pain: a systematic review

    Directory of Open Access Journals (Sweden)

    Miller Peter

    2006-04-01

    Full Text Available Abstract Background Neck pain is a common problem and different forms of manual therapy are used in its treatment. The purpose of this systematic review was to critically appraise the literature that directly compared manipulation, mobilisation and the Activator instrument for non-specific neck pain. Methods Electronic databases (MEDLINE, MANTIS and CINAHL were searched from their inception to October 2005 for all English language randomised clinical trials that directly compared manipulation, mobilisation and the Activator instrument. Inclusion and exclusion criteria were applied to select the studies and these studies were then evaluated using validated criteria. Results Five such studies were identified. The methodological quality was mostly poor. Findings from the studies were mixed and no one therapy was shown to be more effective than the others. Conclusion Further high quality research has to be done before a recommendation can be made as to the most effective manual method for non-specific neck pain.

  1. Elemental analysis using instrumental neutron activation analysis and inductively coupled plasma atomic emission spectrometry: a comparative study

    International Nuclear Information System (INIS)

    Chung, Yong Sam; Choi, Kwang Soon; Moon, Jong Hwa; Kim, Sun Ha; Lim, Jong Myoung; Kim, Young Jin; Quraishi, Shamshad Begum

    2003-05-01

    Elemental analyses for certified reference materials were carried out using instrumental neutron activation analysis and inductively coupled plasma-atomic emission spectrometry. Five Certified Reference Materials (CRM) were selected for the study on comparative analysis of environmental samples. The CRM are Soil (NIST SRM 2709), Coal fly ash (NIST SRM 1633a), urban dust (NIST SRM 1649a) and air particulate on filter media (NIST SRM 2783 and human hair (GBW 09101)

  2. The tenure gap in electoral participation: Instrumental motivation or selection bias? Comparing homeowners and tenants across four housing regimes

    OpenAIRE

    André, S.C.H.; Dewilde, C.L.; Luijkx, R.

    2017-01-01

    Integrating housing tenure in Instrumental Motivation Theory predicts a tenure gap in electoral participation, as homeowners would be more motivated to vote compared with tenants. The empirical question is whether this effect is causal or rather due to selection into different housing tenures. This question is tackled using coarsened exact matching (CEM) on data for 19 countries, allowing us to better control for endogeneity. Even then, homeowners are found to vote more often than tenants. Th...

  3. The balanced scorecard as a potential instrument for supporting planning and improvement in accounting education: Comparative survey findings

    Directory of Open Access Journals (Sweden)

    CJ Cronje

    2004-04-01

    Full Text Available This paper is firstly a comparison of the components of a potential balanced scorecard for accounting departments of universities in South Africa and Australia. Secondly, the various suggested measurement criteria of the balanced scorecard components are also compared. The findings of the research paper indicate no significant differences. The conclusion is that the balanced scorecard constitutes a potential instrument for supporting the planning and improvement of the accounting education environment.

  4. Miniaturization limitations of rotary internal combustion engines

    International Nuclear Information System (INIS)

    Wang, Wei; Zuo, Zhengxing; Liu, Jinxiang

    2016-01-01

    Highlights: • Developed a phenomenological model for rotary internal combustion engines. • Presented scaling laws for the performance of micro rotary engines. • Adiabatic walls can improve the cycle efficiency but result in higher charge leakage. • A lower compression ratio can increase the efficiency due to lower mass losses. • Presented possible minimum engine size of rotary internal combustion engines. - Abstract: With the rapid development of micro electro-mechanical devices, the demands for micro power generation systems have significantly increased in recent years. Traditional chemical batteries have energy densities much lower than hydrocarbon fuels, which makes internal-combustion-engine an attractive technological alternative to batteries. Micro rotary internal combustion engine has drawn great attractions due to its planar design, which is well-suited for fabrication in MEMS. In this paper, a phenomenological model considering heat transfer and mass leakage has been developed to investigate effects of engine speed, compression ratio, blow-by and heat transfer on the performance of micro rotary engine, which provide the guidelines for preliminary design of rotary engine. The lower possible miniaturization limits of rotary combustion engines are proposed.

  5. Floating seal system for rotary devices

    Science.gov (United States)

    Banasiuk, H.A.

    1983-08-23

    This invention relates to a floating seal system for rotary devices to reduce gas leakage around the rotary device in a duct and across the face of the rotary device to an adjacent duct. The peripheral seal bodies are made of resilient material having a generally U-shaped cross section wherein one of the legs is secured to a support member and the other of the legs forms a contacting seal against the rotary device. The legs of the peripheral seal form an extended angle of intersection of about 10[degree] to about 30[degree] in the unloaded condition to provide even sealing forces around the periphery of the rotary device. The peripheral seal extends around the periphery of the support member except where intersected by radial seals which reduce gas leakage across the face of the rotary device and between adjacent duct portions. The radial seal assembly is fabricated from channel bars, the smaller channel bar being secured to the divider of the support member and a larger inverted rigid floating channel bar having its legs freely movable over the legs of the smaller channel bar forming therewith a tubular channel. A resilient flexible tube is positioned within the tubular channel for substantially its full length to reduce gas leakage across the tubular channel. A spacer extends beyond the face of the floating channel near each end of the floating channel a distance to provide desired clearance between the floating channel and the face of the rotary device. 5 figs.

  6. CFD analysis of a rotary kiln using for plaster production and discussion of the effects of flue gas recirculation application

    Science.gov (United States)

    Gürtürk, Mert; Oztop, Hakan F.; Pambudi, Nugroho Agung

    2018-04-01

    In this study, the CFD analysis of the rotary kiln is carried out for examining effects of various parameters on energy consumption and efficiency of the rotary kiln. The flue gas recirculation using in many applications is a useful method for combusting of fuel unburned in the flue gas. Also, effects of flue gas recirculation on the combusting of fuel, operating temperature and efficiency of the rotary kiln are discussed in this study. The rotary kiln, which is considered in this study, is used in plaster plant. Two different CFD models were created and these models are compared according to many parameters such as temperature distribution, mixture fraction, the mass fraction of O2, CO, CO and CH4 in the combustion chamber. It is found that the plaster plant has a great potential for an increase in energy efficiency. Results obtained for producers of rotary kiln and burner will be useful for determining better design parameters.

  7. Rotary Stirling-Cycle Engine And Generator

    Science.gov (United States)

    Chandler, Joseph A.

    1990-01-01

    Proposed electric-power generator comprises three motor generators coordinated by microprocessor and driven by rotary Stirling-cycle heat engine. Combination offers thermodynamic efficiency of Stirling cycle, relatively low vibration, and automatic adjustment of operating parameters to suit changing load on generator. Rotary Stirling cycle engine converts heat to power via compression and expansion of working gas between three pairs of rotary pistons on three concentric shafts in phased motion. Three motor/generators each connected to one of concentric shafts, can alternately move and be moved by pistons. Microprocessor coordinates their operation, including switching between motor and generator modes at appropriate times during each cycle.

  8. Hand and nickel-titanium root canal instrumentation performed by dental students: a micro-computed tomographic study.

    Science.gov (United States)

    Peru, M; Peru, C; Mannocci, F; Sherriff, M; Buchanan, L S; Pitt Ford, T R

    2006-02-01

    The aim of this study was to evaluate root canals instrumented by dental students using the modified double-flared technique, nickel-titanium (NiTi) rotary System GT files and NiTi rotary ProTaper files by micro-computed tomography (MCT). A total of 36 root canals from 18 mesial roots of mandibular molar teeth were prepared; 12 canals were prepared with the modified double-flared technique, using K-flexofiles and Gates-Glidden burs; 12 canals were prepared using System GT and 12 using ProTaper rotary files. Each root was scanned using MCT preoperatively and postoperatively. At the coronal and mid-root sections, System GT and ProTaper files produced significantly less enlarged canal cross-sectional area, volume and perimeter than the modified double-flared technique (P ProTaper (P ProTaper and System GT were able to prepare root canals with little or no procedural error compared with the modified double-flared technique. Under the conditions of this study, inexperienced dental students were able to prepare curved root canals with rotary files with greater preservation of tooth structure, low risk of procedural errors and much quicker than with hand instruments.

  9. Instrumentation for comparing night sky quality and atmospheric conditions of CTA site candidates

    International Nuclear Information System (INIS)

    Fruck, C.; Schweizer, T.; Häfner, D.; Lorentz, E.; Teshima, M.; Gaug, M.; Ernenwein, J.-P.; Costantini, H.; Mandát, D.; Pech, M.; Bulik, T.; Cieslar, M.; Dominik, M.; Ebr, J.; Garczarczyk, M.; Pareschi, G.; Puerto-Giménez, I.

    2015-01-01

    Many atmospheric and climatic criteria have to be taken into account for the selection of a suitable site for the next generation of imaging air-shower Cherenkov telescopes, the ''Cherenkov Telescope Array'' CTA. Such data are not available with sufficient precision, thus a comparison of the proposed sites and final decision based on a comprehensive characterization is impossible. Identical cross-calibrated instruments have been developed which allow for precise comparison between sites, the cross-validation of existing data, and the ground-validation of satellite data. The site characterization work package of the CTA consortium opted to construct and deploy 9 copies of an autonomous multi-purpose weather sensor, incorporating an infrared cloud sensor, a newly developed sensor for measuring the light of the night sky, and an All-Sky-Camera, the whole referred to as Autonomous Tool for Measuring Observatory Site COnditions PrEcisely (ATMOSCOPE). We present here the hardware that was combined into the ATMOSCOPE and characterize its performance

  10. Ultrasonic rotary-hammer drill

    Science.gov (United States)

    Bar-Cohen, Yoseph (Inventor); Badescu, Mircea (Inventor); Sherrit, Stewart (Inventor); Bao, Xiaoqi (Inventor); Kassab, Steve (Inventor)

    2010-01-01

    A mechanism for drilling or coring by a combination of sonic hammering and rotation. The drill includes a hammering section with a set of preload weights mounted atop a hammering actuator and an axial passage through the hammering section. In addition, a rotary section includes a motor coupled to a drive shaft that traverses the axial passage through the hammering section. A drill bit is coupled to the drive shaft for drilling by a combination of sonic hammering and rotation. The drill bit includes a fluted shaft leading to a distal crown cutter with teeth. The bit penetrates sampled media by repeated hammering action. In addition, the bit is rotated. As it rotates the fluted bit carries powdered cuttings helically upward along the side of the bit to the surface.

  11. Rotary Valve FY 2016 Highlights

    Energy Technology Data Exchange (ETDEWEB)

    Fitsos, P. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2016-12-07

    The fiscal year started with the Rotary Valve (RV) being reassembled after having crashed in June of 2015. The crash occurred when the RV inner surface contacted the housing. The cause of the crash was never confirmed. No particles were found in the 2.5 thousandths of an inch gap and the filters the helium gas passed through were all clean. There were marks on the bearings that looked like electrostatic discharge as shown below in Figure 1. These marks hadn’t been seen before and there were similar discharge marks on some of the ball bearings. Examples of this were found in a literature search of bearing failures. This leads to a possible cause due to this arcing affecting the rotational accuracy of the bearings driving the RV into the housing.

  12. Rotary wave-ejector enhanced pulse detonation engine

    Science.gov (United States)

    Nalim, M. R.; Izzy, Z. A.; Akbari, P.

    2012-01-01

    The use of a non-steady ejector based on wave rotor technology is modeled for pulse detonation engine performance improvement and for compatibility with turbomachinery components in hybrid propulsion systems. The rotary wave ejector device integrates a pulse detonation process with an efficient momentum transfer process in specially shaped channels of a single wave-rotor component. In this paper, a quasi-one-dimensional numerical model is developed to help design the basic geometry and operating parameters of the device. The unsteady combustion and flow processes are simulated and compared with a baseline PDE without ejector enhancement. A preliminary performance assessment is presented for the wave ejector configuration, considering the effect of key geometric parameters, which are selected for high specific impulse. It is shown that the rotary wave ejector concept has significant potential for thrust augmentation relative to a basic pulse detonation engine.

  13. Effects of multiple root canal usage on the surface topography and fracture of two different Ni-Ti rotary file systems

    Directory of Open Access Journals (Sweden)

    Jojo Kottoor

    2013-01-01

    Full Text Available Aim: The purpose of this study was to evaluate the effect of multiple root canal usage on the surface topography and fracture of Twisted File (TF and ProTaper (PT rotary Ni-Ti file systems, using scanning electron microscope (SEM. Materials and Methods: Ten sets of PT and TF instruments were used to prepare the mesial canals of mandibular first molars. TF 25, 0.06 taper and PT F1 instruments were analyzed by SEM when new and thereafter every three root canal usages. This sequence was repeated for both the TF and PT groups until 12 uses. Two images of the instrument were recorded, one of the instrument tip and the other 5 mm from the tip, both at ×100 magnification. The sequential use was continued till the instrument fractured and the number of root canal usages for the file to fracture was noted. All fracture surfaces were examined under the SEM. Results: Fresh TF instruments showed no surface wear when compared to PT instruments (P 0.05, while at the 9 th usage TF showed a steep increase in the spiral distortion score when compared to PT (P < 0.05. PT instruments fractured at a mean root canal usage of 17.4, while TF instruments showed a mean root canal usage of 11.8. Fractographically, all the TF instruments failed due to torsion, while all the PT instruments failed because of cyclic fatigue. Conclusion: PT instruments showed more resistance to fracture than TF instruments.

  14. Studies on the instrumental neutron activation analysis by cadmium ratio method and pair comparator method

    Energy Technology Data Exchange (ETDEWEB)

    Chao, H E; Lu, W D; Wu, S C

    1977-12-01

    The cadmium ratio method and pair comparator method provide a solution for the effects on the effective activation factors resulting from the variation of neutron spectrum at different irradiation positions as usually encountered in the single comparator method. The relations between the activation factors and neutron spectrum in terms of cadmium ratio of the comparator Au or of the activation factor of Co-Au pair for the elements, Sc, Cr, Mn, Co, La, Ce, Sm, and Th have been determined. The activation factors of the elements at any irradiation position can then be obtained from the cadmium ratio of the comparator and/or the activation factor of the comparator pair. The relations determined should be able to apply to different reactors and/or different positions of a reactor. It is shown that, for the isotopes /sup 46/Sc, /sup 51/Cr, /sup 56/Mn, /sup 60/Co, /sup 140/La, /sup 141/Ce, /sup 153/Sm and /sup 233/Pa, the thermal neutron activation factors determined by these two methods were generally in agreement with theoretical values. Their I/sub 0//sigma/sub th/ values appeared to agree with literature values also. The methods were applied to determine the contents of elements Sc, Cr, Mn, La, Ce, Sm, and Th in U.S.G.S. Standard Rock G-2, and the results were also in agreement with literature values. The cadmium ratio method and pair comparator method improved the single comparator method, and they are more suitable to analysis for multi-elements of a large number of samples.

  15. Conceptual Study of Rotary-Wing Microrobotics

    National Research Council Canada - National Science Library

    Chabak, Kelson D

    2008-01-01

    This thesis presents a novel rotary-wing micro-electro-mechanical systems (MEMS) robot design. Two MEMS wing designs were designed, fabricated and tested including one that possesses features conducive to insect level aerodynamics...

  16. Rotary drum for distilling bituminous material

    Energy Technology Data Exchange (ETDEWEB)

    1921-11-02

    A rotary drum with insert tubes for distilling bituminous materials, like mineral coal, brown coal, wood, peat, and oil-shale, is characterized in that the insert tube is heated also by superheated steam introduced into the drum.

  17. Apical extrusion of debris in four different endodontic instrumentation systems: A meta-analysis.

    Science.gov (United States)

    Western, J Sylvia; Dicksit, Daniel Devaprakash

    2017-01-01

    All endodontic instrumentation systems tested so far, promote apical extrusion of debris, which is one of the main causes of postoperative pain, flare ups, and delayed healing. Of this meta-analysis was to collect and analyze in vitro studies quantifying apically extruded debris while using Hand ProTaper (manual), ProTaper Universal (rotary), Wave One (reciprocating), and self-adjusting file (SAF; vibratory) endodontic instrumentation systems and to determine methods which produced lesser extrusion of debris apically. An extensive electronic database search was done in PubMed, Scopus, Cochrane, LILACS, and Google Scholar from inception until February 2016 using the key terms "Apical Debris Extrusion, extruded material, and manual/rotary/reciprocating/SAF systems." A systematic search strategy was followed to extract 12 potential articles from a total of 1352 articles. The overall effect size was calculated from the raw mean difference of weight of apically extruded debris. Statistically significant difference was seen in the following comparisons: SAF ProTaper. Apical extrusion of debris was invariably present in all the instrumentation systems analyzed. SAF system seemed to be periapical tissue friendly as it caused reduced apical extrusion compared to Rotary ProTaper and Wave One.

  18. The Comparative Ratings and Indices as the Instruments of Measurement of Political Stability

    Directory of Open Access Journals (Sweden)

    Анна Олеговна Ярославцева

    2012-06-01

    Full Text Available In the given article the main comparative ratings and indices of measurement of political stability in different countries are analyzed. The author proves that despite the broad acknowledgement and heuristic value of these ratings they often lack objectivity when depict situation in Russia.

  19. Third Graders Explore Sound Concepts through Online Research Compared to Making Musical Instruments

    Science.gov (United States)

    Borsay, Kyrie D.; Foss, Page

    2016-01-01

    This study is an exploration of several lessons on sound taught to third grade students using one of the Next Generation Science Standards (3-5-ETS1) and arts integration. A counterbalanced, pretest- posttest- distal posttest design experiment was conducted to compare student knowledge and attitudes between the control and experimental conditions.…

  20. Encapsulated Ball Bearings for Rotary Micro Machines

    Science.gov (United States)

    2007-01-01

    occurrence as well as the overall tribological properties of the bearing mechanism. Firstly, the number of stainless steel balls influences not only the load...stacks.iop.org/JMM/17/S224 Abstract We report on the first encapsulated rotary ball bearing mechanism using silicon microfabrication and stainless steel balls...The method of capturing stainless steel balls within a silicon race to support a silicon rotor both axially and radially is developed for rotary micro

  1. Rotary drum dryers for coal slurries

    Energy Technology Data Exchange (ETDEWEB)

    Baunack, F

    1983-04-01

    The suitability, sizing and internal equipment of rotary drum dryers for high-ash coal slurries are discussed. Rotary dryers will handle also difficult slurries; by suitable drum sizes, lifter blades and chains not only high specific evaporation capacities can be achieved but also very high throughputs of up to 400 tons/h of finished product and high evaporation capacities of 60 tons/h.

  2. Evaluation of Root Canal Cleaning and Shaping Efficacy of Three Engine-driven Instruments: SafeSider, ProTaper Universal and Lightspeed LSX.

    Science.gov (United States)

    Wigler, Ronald; Koren, Tal; Tsesis, Igor

    2015-11-01

    To compare the cleaning effectiveness and shaping ability of SafeSider, ProTaper Universal and Lightspeed rotary instruments during the preparation of curved root canals in extracted human teeth. A total of 63 roots with curved root canals were divided into three groups. Canals were prepared using SafeSider, ProTaper Universal or Lightspeed LSX. Using pre- and post-instrumentation radiographs, straightening of the canal curvatures and loss of working length were determined with a computer image analysis program. The amounts of debris at the apical 5 mm were quantified on the basis of a numerical evaluation scale. The data were analyzed statistically using the two-way analysis of variance (ANOVA). There was significantly more transportation among the Lightspeed LSX group compared to the SafeSider and ProTaper Universal groups only at the 4 mm level (p engine-driven instruments with regards to debris removal. SafeSider, ProTaper Universal and Lightspeed LSX rotary instruments maintained the original canal curvature well at the apical 3 mm and were safe to use. No difference was found in cleaning efficacy and none rendered the apical part of the canal free of debris. SafeSider, ProTaper Universal and Lightspeed LSX rotary instruments are safe to use in curved root canals.

  3. Experimental analysis of IMEP in a rotary combustion engine. [Indicated Mean Effective Pressure

    Science.gov (United States)

    Schock, H. J.; Rice, W. J.; Meng, P. R.

    1981-01-01

    This experimental work demonstrates the use of a NASA designed, real time Indicated Mean Effective Pressure (IMEP) measurement system which will be used to judge proposed improvements in cycle efficiency of a rotary combustion engine. This is the first self-contained instrument that is capable of making real time measurements of IMEP in a rotary engine. Previous methods used require data recording and later processing using a digital computer. The unique features of this instrumentation include its ability to measure IMEP on a cycle by cycle, real time basis and the elimination of the need to differentiate the volume function in real time. Measurements at two engine speeds (2000 and 3000 RPM) and a full range of loads are presented, although the instrument was designed to operate to speeds of 9000 RPM.

  4. Cleaning efficacy of reciprocal and rotary systems in the removal of root canal filling material

    Science.gov (United States)

    Koçak, Mustafa Murat; Koçak, Sibel; Türker, Sevinç Aktemur; Sağlam, Baran Can

    2016-01-01

    Aim: The aim of this study was to compare the efficacy of hand file, nickel titanium rotary instrument, and two reciprocating instruments for removing gutta-percha and sealer from the root canals. Materials and Methods: Eighty-eight mandibular premolar teeth were used. The root canals were shaped and filled with gutta-percha and a resin-based sealer. The specimens were divided into four groups according to the technique by which the root filling material was removed: Group 1 — Wave One; Group 2 — Reciproc; Group 3 — ProTaper; and Group 4 — Gates-Glidden burs and stainless steel hand file. Then teeth were split longitudinally and photographed. The images were transferred to a computer. The ratio of remaining filling material to the root canal periphery was calculated with the aid of ImageJ software. Statistical analysis was performed using Kruskal–Wallis and Mann–Whitney tests. Results: A significant difference was found among all groups (P hand file. Conclusion: The reciprocating files were found to be significantly more effective in removing the filling material from the canal walls compared to the rotational file and hand file. PMID:27099429

  5. Comparative study of conditions and instruments of economic regulation of networked public services

    International Nuclear Information System (INIS)

    Henry, Claude; Curien, Nicolas; Gassner, Katharina; Krom, Hans de

    1999-11-01

    In order to provide a comparative view on implemented regulations regarding networked public services like electric power distribution, train transport, telecommunications, or mail services, this collective publication gathers six studies which respectively address the cases of Germany, Spain, Italy, the Netherlands, the United Kingdom, and Sweden. For each of them, the authors report, analyse and discuss the evolution and implementation of regulation or deregulation processes, the content of the relevant laws which can be specific to a sector, the role and the importance of public and private actors, and the market status and operation

  6. Study of advanced rotary combustion engines for commuter aircraft

    Science.gov (United States)

    Berkowitz, M.; Jones, C.; Myers, D.

    1983-01-01

    Performance, weight, size, and maintenance data for advanced rotary aircraft engines suitable for comparative commuter aircraft system evaluation studies of alternate engine candidates are provided. These are turbocharged, turbocompounded, direct injected, stratified charge rotary engines. Hypothetical engines were defined (an RC4-74 at 895 kW and an RC6-87 at 1490 kW) based on the technologies and design approaches used in the highly advanced engine of a study of advanced general aviation rotary engines. The data covers the size range of shaft power from 597 kW (800 hp) to 1865 kW (2500 hp) and is in the form of drawings, tables, curves and written text. These include data on internal geometry and configuration, installation information, turbocharging and turbocompounding arrangements, design features and technologies, engine cooling, fuels, scaling for weight size BSFC and heat rejection for varying horsepower, engine operating and performance data, and TBO and maintenance requirements. The basic combustion system was developed and demonstrated; however the projected power densities and performance efficiencies require increases in engine internal pressures, thermal loading, and rotative speed.

  7. Multi-Fuel Rotary Engine for General Aviation Aircraft

    Science.gov (United States)

    Jones, C.; Ellis, D. R.; Meng, P. R.

    1983-01-01

    Design studies, conducted for NASA, of Advanced Multi-fuel General Aviation and Commuter Aircraft Rotary Stratified Charge Engines are summarized. Conceptual design studies of an advanced engine sized to provide 186/250 shaft KW/HP under cruise conditions at 7620/25,000 m/ft. altitude were performed. Relevant engine development background covering both prior and recent engine test results of the direct injected unthrottled rotary engine technology, including the capability to interchangeably operate on gasoline, diesel fuel, kerosene, or aviation jet fuel, are presented and related to growth predictions. Aircraft studies, using these resultant growth engines, define anticipated system effects of the performance and power density improvements for both single engine and twin engine airplanes. The calculated results indicate superior system performance and 30 to 35% fuel economy improvement for the Rotary-engine airplanes as compared to equivalent airframe concept designs with current baseline engines. The research and technology activities required to attain the projected engine performance levels are also discussed.

  8. Design and multi-physics optimization of rotary MRF brakes

    Science.gov (United States)

    Topcu, Okan; Taşcıoğlu, Yiğit; Konukseven, Erhan İlhan

    2018-03-01

    Particle swarm optimization (PSO) is a popular method to solve the optimization problems. However, calculations for each particle will be excessive when the number of particles and complexity of the problem increases. As a result, the execution speed will be too slow to achieve the optimized solution. Thus, this paper proposes an automated design and optimization method for rotary MRF brakes and similar multi-physics problems. A modified PSO algorithm is developed for solving multi-physics engineering optimization problems. The difference between the proposed method and the conventional PSO is to split up the original single population into several subpopulations according to the division of labor. The distribution of tasks and the transfer of information to the next party have been inspired by behaviors of a hunting party. Simulation results show that the proposed modified PSO algorithm can overcome the problem of heavy computational burden of multi-physics problems while improving the accuracy. Wire type, MR fluid type, magnetic core material, and ideal current inputs have been determined by the optimization process. To the best of the authors' knowledge, this multi-physics approach is novel for optimizing rotary MRF brakes and the developed PSO algorithm is capable of solving other multi-physics engineering optimization problems. The proposed method has showed both better performance compared to the conventional PSO and also has provided small, lightweight, high impedance rotary MRF brake designs.

  9. Geometric analysis of root canals prepared by four rotary NiTi shaping systems.

    Science.gov (United States)

    Hashem, Ahmed Abdel Rahman; Ghoneim, Angie Galal; Lutfy, Reem Ahmed; Foda, Manar Yehia; Omar, Gihan Abdel Fatah

    2012-07-01

    A great number of nickel-titanium (NiTi) rotary systems with noncutting tips, different cross-sections, superior resistance to torsional fracture, varying tapers, and manufacturing method have been introduced to the market. The purpose of this study was to evaluate and compare the effect of 4 rotary NiTi preparation systems, Revo-S (RS; Micro-Mega, Besancon Cedex, France), Twisted file (TF; SybronEndo, Amersfoort, The Netherlands), ProFile GT Series X (GTX; Dentsply, Tulsa Dental Specialties, Tulsa, OK), and ProTaper (PT; Dentsply Maillefer, Ballaigues, Switzerland), on volumetric changes and transportation of curved root canals. Forty mesiobuccal canals of mandibular molars with an angle of curvature ranging from 25° to 40° were divided according to the instrument used in canal preparation into 4 groups of 10 samples each: group RS, group TF, group GTX, and group PT. Canals were scanned using an i-CAT CBCT scanner (Imaging Science International, Hatfield, PA) before and after preparation to evaluate the volumetric changes. Root canal transportation and centering ratio were evaluated at 1.3, 2.6, 5.2, and 7.8 mm from the apex. The significance level was set at P ≤ .05. The PT system removed a significantly higher amount of dentin than the other systems (P = .025). At the 1.3-mm level, there was no significant difference in canal transportation and centering ratio among the groups. However, at the other levels, TF maintained the original canal curvature recording significantly the least degree of canal transportation as well as the highest mean centering ratio. The TF system showed superior shaping ability in curved canals. Revo-S and GTX were better than ProTaper regarding both canal transportation and centering ability. Copyright © 2012 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  10. ACCELERATED SITE TECHNOLOGY DEPLOYMENT COST AND PERFORMANCE REPORT COMPARABILITY OF ISOCS INSTRUMENT IN RADIONUCLIDE CHARACTERICATION AT BROOKHAVEN NATIONAL LABORATORY

    Energy Technology Data Exchange (ETDEWEB)

    KALB,P.; LUCKETT,L.; MILLER,K.; GOGOLAK,C.; MILIAN,L.

    2001-03-01

    This report describes a DOE Accelerated Site Technology Deployment project being conducted at Brookhaven National Laboratory to deploy innovative, radiological, in situ analytical techniques. The technologies are being deployed in support of efforts to characterize the Brookhaven Graphite Research Reactor (BGRR) facility, which is currently undergoing decontamination and decommissioning. This report focuses on the deployment of the Canberra Industries In Situ Object Counting System (ISOCS) and assesses its data comparability to baseline methods of sampling and laboratory analysis. The battery-operated, field deployable gamma spectrometer provides traditional spectra of counts as a function of gamma energy. The spectra are then converted to radionuclide concentration by applying innovative efficiency calculations using monte carlo statistical methods and pre-defined geometry templates in the analysis software. Measurement of gamma emitting radionuclides has been accomplished during characterization of several BGRR components including the Pile Fan Sump, Above Ground Ducts, contaminated cooling fans, and graphite pile internals. Cs-137 is the predominant gamma-emitting radionuclide identified, with smaller quantities of Co-60 and Am-241 detected. The Project used the Multi-Agency Radiation Survey and Site Investigation Manual guidance and the Data Quality Objectives process to provide direction for survey planning and data quality assessment. Analytical results have been used to calculate data quality indicators (DQI) for the ISOCS measurements. Among the DQIs assessed in the report are sensitivity, accuracy, precision, bias, and minimum detectable concentration. The assessment of the in situ data quality using the DQIs demonstrates that the ISOCS data quality can be comparable to definitive level laboratory analysis when the field instrument is supported by an appropriate Quality Assurance Project Plan. A discussion of the results obtained by ISOCS analysis of

  11. ACCELERATED SITE TECHNOLOGY DEPLOYMENT COST AND PERFORMANCE REPORT COMPARABILITY OF ISOCS INSTRUMENT IN RADIONUCLIDE CHARACTERICATION AT BROOKHAVEN NATIONAL LABORATORY

    International Nuclear Information System (INIS)

    KALB, P.; LUCKETT, L.; MILLER, K.; GOGOLAK, C.; MILIAN, L.

    2001-01-01

    This report describes a DOE Accelerated Site Technology Deployment project being conducted at Brookhaven National Laboratory to deploy innovative, radiological, in situ analytical techniques. The technologies are being deployed in support of efforts to characterize the Brookhaven Graphite Research Reactor (BGRR) facility, which is currently undergoing decontamination and decommissioning. This report focuses on the deployment of the Canberra Industries In Situ Object Counting System (ISOCS) and assesses its data comparability to baseline methods of sampling and laboratory analysis. The battery-operated, field deployable gamma spectrometer provides traditional spectra of counts as a function of gamma energy. The spectra are then converted to radionuclide concentration by applying innovative efficiency calculations using monte carlo statistical methods and pre-defined geometry templates in the analysis software. Measurement of gamma emitting radionuclides has been accomplished during characterization of several BGRR components including the Pile Fan Sump, Above Ground Ducts, contaminated cooling fans, and graphite pile internals. Cs-137 is the predominant gamma-emitting radionuclide identified, with smaller quantities of Co-60 and Am-241 detected. The Project used the Multi-Agency Radiation Survey and Site Investigation Manual guidance and the Data Quality Objectives process to provide direction for survey planning and data quality assessment. Analytical results have been used to calculate data quality indicators (DQI) for the ISOCS measurements. Among the DQIs assessed in the report are sensitivity, accuracy, precision, bias, and minimum detectable concentration. The assessment of the in situ data quality using the DQIs demonstrates that the ISOCS data quality can be comparable to definitive level laboratory analysis when the field instrument is supported by an appropriate Quality Assurance Project Plan. A discussion of the results obtained by ISOCS analysis of

  12. Comparative measurement of inorganic elements in Korean space foods using instrumental neutron activation analysis

    International Nuclear Information System (INIS)

    Chung, Yong Sam; Kim, Sun Ha; Baek, Sung Ryel; Sun, Gwang Min; Moon, Jong Hwa; Choi, Jong Il; Lee, Joo Eun

    2012-01-01

    In April 2008, Korea's first astronaut became a crew member of the international space station and she brought special space versions of traditional Korean dishes such as kimchi, boiled rice, hot red pepper paste, soybean paste soup, ginseng tea, green tea, and ramyun. To date, seventy kinds of Korean space foods (KSFs) have been developed by KAERI. The information and role of trace mineral elements from an intake of created and processed foodstuff are important as a indicator of human health and nutrition, as well as a quality control of food and diet. In particular, special food created for consumption by astronauts in outer space may differ with common food on the earth to compensate a decrease in taste and nutrition by hygienic sterilization processing as well as strong cosmic rays, a state of non gravitation, low pressure, and an enclosed space environment. An accurate quantitative analysis of trace elements in various kinds of biological samples is serious work for analytical data quality. An neutron activation analysis is a sensitive, non destructive, multi elemental analytical method without loss and contamination of a sample by chemical pre treatment. The aim of this study is to identify and to compare the distribution of concentrations for essential and functional inorganic elements in six kinds of Korean space foods developed by KAERI in 2011 using INAA

  13. Comparative measurement of inorganic elements in Korean space foods using instrumental neutron activation analysis

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Yong Sam; Kim, Sun Ha; Baek, Sung Ryel; Sun, Gwang Min; Moon, Jong Hwa; Choi, Jong Il; Lee, Joo Eun [KAERI, Daejeon (Korea, Republic of)

    2012-10-15

    In April 2008, Korea's first astronaut became a crew member of the international space station and she brought special space versions of traditional Korean dishes such as kimchi, boiled rice, hot red pepper paste, soybean paste soup, ginseng tea, green tea, and ramyun. To date, seventy kinds of Korean space foods (KSFs) have been developed by KAERI. The information and role of trace mineral elements from an intake of created and processed foodstuff are important as a indicator of human health and nutrition, as well as a quality control of food and diet. In particular, special food created for consumption by astronauts in outer space may differ with common food on the earth to compensate a decrease in taste and nutrition by hygienic sterilization processing as well as strong cosmic rays, a state of non gravitation, low pressure, and an enclosed space environment. An accurate quantitative analysis of trace elements in various kinds of biological samples is serious work for analytical data quality. An neutron activation analysis is a sensitive, non destructive, multi elemental analytical method without loss and contamination of a sample by chemical pre treatment. The aim of this study is to identify and to compare the distribution of concentrations for essential and functional inorganic elements in six kinds of Korean space foods developed by KAERI in 2011 using INAA.

  14. Performance and efficiency evaluation and heat release study of a direct-injection stratified-charge rotary engine

    Science.gov (United States)

    Nguyen, H. L.; Addy, H. E.; Bond, T. H.; Lee, C. M.; Chun, K. S.

    1987-01-01

    A computer simulation which models engine performance of the Direct Injection Stratified Charge (DISC) rotary engines was used to study the effect of variations in engine design and operating parameters on engine performance and efficiency of an Outboard Marine Corporation (OMC) experimental rotary combustion engine. Engine pressure data were used in a heat release analysis to study the effects of heat transfer, leakage, and crevice flows. Predicted engine data were compared with experimental test data over a range of engine speeds and loads. An examination of methods to improve the performance of the rotary engine using advanced heat engine concepts such as faster combustion, reduced leakage, and turbocharging is also presented.

  15. Performance characterization of Watson Ahumada motion detector using random dot rotary motion stimuli.

    Directory of Open Access Journals (Sweden)

    Siddharth Jain

    Full Text Available The performance of Watson & Ahumada's model of human visual motion sensing is compared against human psychophysical performance. The stimulus consists of random dots undergoing rotary motion, displayed in a circular annulus. The model matches psychophysical observer performance with respect to most parameters. It is able to replicate some key psychophysical findings such as invariance of observer performance to dot density in the display, and decrease of observer performance with frame duration of the display.Associated with the concept of rotary motion is the notion of a center about which rotation occurs. One might think that for accurate estimation of rotary motion in the display, this center must be accurately known. A simple vector analysis reveals that this need not be the case. Numerical simulations confirm this result, and may explain the position invariance of MST(d cells. Position invariance is the experimental finding that rotary motion sensitive cells are insensitive to where in their receptive field rotation occurs.When all the dots in the display are randomly drawn from a uniform distribution, illusory rotary motion is perceived. This case was investigated by Rose & Blake previously, who termed the illusory rotary motion the omega effect. Two important experimental findings are reported concerning this effect. First, although the display of random dots evokes perception of rotary motion, the direction of motion perceived does not depend on what dot pattern is shown. Second, the time interval between spontaneous flips in perceived direction is lognormally distributed (mode approximately 2 s. These findings suggest the omega effect fits in the category of a typical bistable illusion, and therefore the processes that give rise to this illusion may be the same processes that underlie much of other bistable phenomenon.

  16. Fabrication works on rotary kiln fluidized bed

    International Nuclear Information System (INIS)

    Shahazrin Mohd Nasir; Mohamad Azman Che Mat Isa; Mohamad Puad Haji Abu; Mohd Fairus Abdul Farid

    2005-01-01

    Rotary kiln has been widely used in incineration and studied by many researches. Solid wastes of various shapes, sizes and heat value can be fed into rotary kiln either in batches or continually. Waste combustion in rotary kiln involves rotation method and the residence time depends on the length and diameter of the rotary kiln and the total stichomythic air given to the system.Rocking system is another technology used in incinerator. In the rocking system, internal elements in the combustion chamber move to transports and mix the burning waste so that all combustible material in the waste is fully burnt. Another technology in incinerator is the fluidized bed. This method uses air to fluidized the sand thus enhancing the combustion process. The total air is controlled in order to obtain a suitable fluidized condition.This preliminary study was conducted to study the feasibility of an incinerator system when three components viz. the rotary kiln, rocking system and fluidized bed are combined. This research was also conducted to obtain preliminary data parameters of the three components such as the suitable temperature, the angle of the kiln, residence time, total air for fluidization, rocking speed and the devolatilization rate. The samples used in this research were the palm oil kernel shells. (Author)

  17. Postoperative pain relief using intrathecal morphine for lumbar spine decompression and instrumentation surgery: A comparative study of two different doses

    Directory of Open Access Journals (Sweden)

    Priyanka Dhir

    2017-01-01

    Full Text Available Background and Aims: Patients undergoing lumbar spine instrumentation surgery suffer severe postoperative pain which is difficult to treat by conventional multimodal analgesic methods. We aimed to compare the analgesic effect of two different doses of intrathecal morphine (ITM 0.2 mg and 0.3 mg in patients undergoing lumbar spine decompression and instrumentation surgery. Design: This was a randomized, prospective, double-blinded study. Materials and Methods: After approval from the Institutional Ethics Committee, forty American Society of Anesthesiologists 1 and 2 patients of either sex aged 18 years or older undergoing lumbar spine surgery were randomly assigned to receive ITM either 0.2 mg (Group A, n = 20 or 0.3 mg (Group B, n = 20 in 2 ml saline before general anesthesia. A morphine intravenous patient-controlled analgesia (PCA device was used for rescue analgesia in the postoperative period. Assessment parameters included hemodynamics, sedation score, pain using numeric rating scale (NRS, total consumption of PCA morphine recorded for 24 h, and patient's satisfaction score. The data were analyzed using Chi-square test for categorical variables and Student's t-test for quantitative variables. Results: NRS score was significantly low in Group B at 4, 8, 12, and 24 h as compared to Group A (P < 0.05. Group B also had decreased requirement for rescue analgesia (P = 0.001 with higher patient satisfaction. There was no significant difference between the two groups in other studied parameters. Conclusions: 0.3 mg ITM provided superior analgesia postoperatively in terms of NRS score and higher patient satisfaction compared to 0.2 mg with no significant difference in the incidence of side effects.

  18. Cone-beam Computed Tomographic Assessment of Canal Centering Ability and Transportation after Preparation with Twisted File and Bio RaCe Instrumentation.

    Directory of Open Access Journals (Sweden)

    Kiamars Honardar

    2014-08-01

    Full Text Available Use of rotary Nickel-Titanium (NiTi instruments for endodontic preparation has introduced a new era in endodontic practice, but this issue has undergone dramatic modifications in order to achieve improved shaping abilities. Cone-beam computed tomography (CBCT has made it possible to accurately evaluate geometrical changes following canal preparation. This study was carried out to compare canal centering ability and transportation of Twisted File and BioRaCe rotary systems by means of cone-beam computed tomography.Thirty root canals from freshly extracted mandibular and maxillary teeth were selected. Teeth were mounted and scanned before and after preparation by CBCT at different apical levels. Specimens were divided into 2 groups of 15. In the first group Twisted File and in the second, BioRaCe was used for canal preparation. Canal transportation and centering ability after preparation were assessed by NNT Viewer and Photoshop CS4 software. Statistical analysis was performed using t-test and two-way ANOVA.All samples showed deviations from the original axes of the canals. No significant differences were detected between the two rotary NiTi instruments for canal centering ability in all sections. Regarding canal transportation however, a significant difference was seen in the BioRaCe group at 7.5mm from the apex.Under the conditions of this in vitro study, Twisted File and BioRaCe rotary NiTi files retained original canal geometry.

  19. Effect of rotary instrumentation and of the association of calcium hydroxide and chlorhexidine on the antisepsis of the root canal system in dogs Efeito da instrumentação automatizada e da associação hidróxido de cálcio e clorexidina na anti-sepsia de canais radiculares de cães

    Directory of Open Access Journals (Sweden)

    Janir Alves Soares

    2006-04-01

    Full Text Available This study aimed at evaluating the antisepsis of the root canal system (RCS and periapical region (PR provided by rotary instrumentation associated with chlorhexidine + calcium hydroxide as intracanal medicament. Chronic periapical lesions were induced in 26 pre-molar roots in two dogs. After microbiological sampling, automatic instrumentation using the Profile system and irrigation with 5.25% sodium hypochlorite solution, with a final rinse of 14.3% EDTA followed by profuse irrigation with physiological saline were carried out in 18 root canals. After drying the canals, a paste based on calcium hydroxide associated with a 2% chlorhexidine digluconate solution was placed inside them. After 21 days, the medication was removed, leaving the root canals empty and coronally sealed. After 96 hours, a final microbiological sample was obtained, followed by histomicrobiological processing by the Brown & Brenn method. Eight untreated root canals represented the control group (C-G. Based on the Mann-Whitney test at a confidence level of 5% (p Este estudo objetivou avaliar a anti-sepsia do sistema de canais radiculares (SCR e da região periapical (RP proporcionada pela instrumentação automatizada associada a medicação intracanal à base de hidróxido de cálcio + clorexidina. Lesões periapicais crônicas foram induzidas em 26 raízes de pré-molares de dois cães. Após amostragem microbiológica, procedeu-se à instrumentação automatizada de 18 canais radiculares (CR utilizando-se o sistema Profile e a solução de hipoclorito de sódio a 5,25%, com irrigação final com EDTA a 14,3%, seguida de irrigação profusa com soro fisiológico. Após se secarem os canais, foi colocada em seu interior uma pasta à base de hidróxido de cálcio P.A. associada à solução de digluconato de clorexidina a 2%. Transcorridos 21 dias, removeu-se a medicação, deixando-se os CR vazios e selados coronariamente. Após 96 horas, obteve-se a amostra microbiol

  20. Rotary bayonets for cryogenic and vacuum service

    International Nuclear Information System (INIS)

    Rucinski, R.A.; Dixon, K.D.; Krasa, R.; Krempetz, K.J.; Mulholland, G.T.; Trotter, G.R.; Urbin, J.B.

    1993-07-01

    Rotary bayonets were designed, tested, and installed for liquid nitrogen, liquid argon, and vacuum service. This paper will present the design, testing, and service record for two sizes of vacuum jacketed cryogenic rotary bayonets and two sizes of vacuum service rotary bayonets. Materials used in construction provide electrical isolation across the bayonet joint. The joint permits 360 degrees of rotation between the male and female pipe sections while maintaining integrity of service. Assemblies using three such joints were built to allow end connection points to be translated through at least 1 meter of horizontal travel while kept in service. Vacuum jacketed sizes built in-house at Fermi National Accelerator Laboratory are 1-1/2 in. inner pipe size, 3 in. vacuum jacket, and 4 in. inner pipe size, 6 in. vacuum jacket The single wall vacuum service bayonets are in 4 in. and 6 in. pipe sizes. The bayonets have successfully been in active service for over one year

  1. A bistable electromagnetically actuated rotary gate microvalve

    International Nuclear Information System (INIS)

    Luharuka, Rajesh; Hesketh, Peter J

    2008-01-01

    Two types of rotary gate microvalves are developed for flow modulation in microfluidic systems. These microvalves have been tested for an open flow rate of up to 100 sccm and operate under a differential pressure of 6 psig with flow modulation of up to 100. The microvalve consists of a suspended gate that rotates in the plane of the chip to regulate flow through the orifice. The gate is suspended by a novel fully compliant in-plane rotary bistable micromechanism (IPRBM) that advantageously constrains the gate in all degrees of freedom except for in-plane rotational motion. Multiple inlet/outlet orifices provide flexibility of operating the microvalve in three different flow configurations. The rotary gate microvalve is switched with an external electromagnetic actuator. The suspended gate is made of a soft magnetic material and its electromagnetic actuation is based on the operating principle of a variable-reluctance stepper motor

  2. Rotary bayonets for cryogenic and vacuum service

    International Nuclear Information System (INIS)

    Rucinski, R.A.; Dixon, K.D.; Krasa, R.; Krempetz, K.J.; Mulholland, G.T.; Trotter, G.R.; Urbin, J.B.

    1994-01-01

    Rotary bayonets were designed, tested, and installed for liquid nitrogen, liquid argon, and vacuum service. This paper will present the design, testing, and service record for two sizes of vacuum jacketed cryogenic rotary bayonets and two sizes of vacuum service rotary bayonets. Materials used in construction provide electrical isolation across the bayonet joint. The joint permits 360 degrees of rotation between the male and female pipe sections while maintaining integrity of service. Assemblies using three such joints were built to allow end connection points to be translated through at least 1 meter of horizontal travel while kept in service. Vacuum jacketed sizes built in-house at Fermi National Accelerator Laboratory are 1 1/2 inches inner pipe size, 3 inches vacuum jacket, and 4 inches inner pipe size, 6 inches vacuum jacket. The single wall vacuum service bayonets are in 4 inch and 6 inch pipe sizes. The bayonets have successfully been in active service for over one year

  3. A study on FlexMaster : a Ni-Ti rotary engine driven system for root canal preparation.

    Science.gov (United States)

    Alam, M S; Bashar, A K; Begumr, J A; Kinoshita, J I

    2006-07-01

    In the present study, the effectiveness of recently introduced rotary Nickel Titanium FlexMaster engine driven system was evaluated for cleaning and shaping of root canals in extracted human teeth and compared with that done by the Nickel Titanium Flexofile hand instruments. A total of 40 root canals from 36 extracted mandibular and maxillary teeth with curvature ranging between 20 and 30 degree were divided into two groups, consisting 20 canals in each. FlexMaster instrumentation was done in 20 canals, using crown-down technique and manual filing with Flexofile was done in other 20 canals, using conventional and step-back techniques. 5.25% sodium hypochlorite (NaOCl) solution and 17% ethelene di-amine tetra-acetic acid (EDTA) were used alternatively for irrigation after canal preparation by each instrument size. Time needed for canal preparation of individual canal was recorded. A procedural error such as instrument breakage was also noted. After preparation, all the roots were cut longitudinally by using diamond burs in turbine handpiece and examined under scanning electron microscope. Apical region was quantified for debris and smear layer based on a 5-score numerical evaluation scale. The data established for scoring the debris and smear layer and preparation time of individual canal were analyzed statistically using the Mann-Whitney U test. Completely cleaned root canals were not found with any of the two instruments and none of the instruments maintained the original canal uniformity and regular dentine surface. Because significantly less debris was found in the apical region using the manual filing technique (p< 0.05). Thus the flexmaster system was found to produce less cleaner root canal walls than manual technique. Only one FlexMaster finishing file sized 30 was separated in the apical region during preparation of 30 degree curved canal. The time taken by FlexMaster was significantly better (p< 0.01) than that of hand instruments.

  4. Fundamental principles of rotary displacement meters

    Energy Technology Data Exchange (ETDEWEB)

    Rosen, J. [Schlumberger Industries, Owenton, KY (United States)

    1995-12-01

    The gas meter exists to continually and accurately measure the volume of gas supplied over the complete flow range of the load. In effect the gas meter serves as the {open_quotes}cash register{close_quotes} of the gas industry; its accurate and dependable performance ensures fair dealings for both the supplier and the user. An investment both in and of itself, the gas meter should be chosen as a function of its usefullness both over the short term and the long term. Thus in addition to initial cost, one must take into account various associated factors, costs and benefits, including the following: Design Characteristics Application, suitability, Meter features and options, Operation constraints, Installation, Service and maintenance, Repair and replacement, Life expectancy, Compatibility with complimentary products, Correcting devices, Remote reading capabilities, Data generation and gathering, Upgradeabilty. This paper will look at one positive displacement meter, the Rotary meter, and address the fundamentals principals of the technology as well as looking at some of the benefits derived from its application. Rotary positive displacement meters were introduced at the end of last century. Used primarily for metering transmission sized loads, the meters` measuring capabilities have extended to cover nearly all areas of distribution with exception of domestic applications. Rotary meters are available in rated capacities from 800 cfh to 102,000 cfh and operating pressures from 175 PSIG to 1440 PSIG. The use of rotary meters on load ranges in the 800 to 10,000 cfh category has increased and is replacing the use of diaphragm meters because of the smaller relative size of rotaries, and improvements in rangeabilities in the last few years. Turbine meters are usually the meter of choice on loads over 16,000 cfh unless a meter with high rangeability is required because of varying load characteristics, in which case a large foot mounted rotary might still be selected.

  5. Methods and apparatus for controlling rotary machines

    Science.gov (United States)

    Bagepalli, Bharat Sampathkumaran [Niskayuna, NY; Jansen, Patrick Lee [Scotia, NY; Barnes, Gary R [Delanson, NY; Fric, Thomas Frank [Greer, SC; Lyons, James Patrick Francis [Niskayuna, NY; Pierce, Kirk Gee [Simpsonville, SC; Holley, William Edwin [Greer, SC; Barbu, Corneliu [Guilderland, NY

    2009-09-01

    A control system for a rotary machine is provided. The rotary machine has at least one rotating member and at least one substantially stationary member positioned such that a clearance gap is defined between a portion of the rotating member and a portion of the substantially stationary member. The control system includes at least one clearance gap dimension measurement apparatus and at least one clearance gap adjustment assembly. The adjustment assembly is coupled in electronic data communication with the measurement apparatus. The control system is configured to process a clearance gap dimension signal and modulate the clearance gap dimension.

  6. Stratified charge rotary engine for general aviation

    Science.gov (United States)

    Mount, R. E.; Parente, A. M.; Hady, W. F.

    1986-01-01

    A development history, a current development status assessment, and a design feature and performance capabilities account are given for stratified-charge rotary engines applicable to aircraft propulsion. Such engines are capable of operating on Jet-A fuel with substantial cost savings, improved altitude capability, and lower fuel consumption by comparison with gas turbine powerplants. Attention is given to the current development program of a 400-hp engine scheduled for initial operations in early 1990. Stratified charge rotary engines are also applicable to ground power units, airborne APUs, shipboard generators, and vehicular engines.

  7. Rotary magnetic refrigerator for superfluid helium production

    International Nuclear Information System (INIS)

    Hakuraku, Y.; Ogata, H.

    1986-01-01

    A new rotary-magnetic refrigerator designed to obtain superfluid helium temperatures by executing a magnetic Carnot cycle is developed. A rotor containing 12 magnetic refrigerants (gadolinium-gallium-garnet) is immersed in liquid helium at 4.2 K and rotated at constant speed in a steady magnetic field distribution. Performance tests demonstrate that the new rotary refrigerator is capable of obtaining a temperature of 1.48 K. The maximum useful cooling power obtained at 1.8 K is 1.81 W which corresponds to a refrigeration efficiency of 34%

  8. Ka-band waveguide rotary joint

    KAUST Repository

    Yevdokymov, Anatoliy

    2013-04-11

    The authors present a design of a waveguide rotary joint operating in Ka-band with central frequency of 33 GHz, which also acts as an antenna mount. The main unit consists of two flanges with a clearance between them; one of the flanges has three circular choke grooves. Utilisation of three choke grooves allows larger operating clearance. Two prototypes of the rotary joint have been manufactured and experimentally studied. The observed loss is from 0.4 to 0.8 dB in 1.5 GHz band.

  9. A Thermoelectric Waste-Heat-Recovery System for Portland Cement Rotary Kilns

    Science.gov (United States)

    Luo, Qi; Li, Peng; Cai, Lanlan; Zhou, Pingwang; Tang, Di; Zhai, Pengcheng; Zhang, Qingjie

    2015-06-01

    Portland cement is produced by one of the most energy-intensive industrial processes. Energy consumption in the manufacture of Portland cement is approximately 110-120 kWh ton-1. The cement rotary kiln is the crucial equipment used for cement production. Approximately 10-15% of the energy consumed in production of the cement clinker is directly dissipated into the atmosphere through the external surface of the rotary kiln. Innovative technology for energy conservation is urgently needed by the cement industry. In this paper we propose a novel thermoelectric waste-heat-recovery system to reduce heat losses from cement rotary kilns. This system is configured as an array of thermoelectric generation units arranged longitudinally on a secondary shell coaxial with the rotary kiln. A mathematical model was developed for estimation of the performance of waste heat recovery. Discussions mainly focus on electricity generation and energy saving, taking a Φ4.8 × 72 m cement rotary kiln as an example. Results show that the Bi2Te3-PbTe hybrid thermoelectric waste-heat-recovery system can generate approximately 211 kW electrical power while saving 3283 kW energy. Compared with the kiln without the thermoelectric recovery system, the kiln with the system can recover more than 32.85% of the energy that used to be lost as waste heat through the kiln surface.

  10. Evaluation of the Self-Adjusting File system (SAF) for the instrumentation of primary molar root canals: a micro-computed tomographic study.

    Science.gov (United States)

    Kaya, E; Elbay, M; Yiğit, D

    2017-06-01

    The Self-Adjusting File (SAF) system has been recommended for use in permanent teeth since it offers more conservative and effective root-canal preparation when compared to traditional rotary systems. However, no study had evaluated the usage of SAF in primary teeth. The aim of this study was to evaluate and compare the use of SAF, K file (manual instrumentation) and Profile (traditional rotary instrumentation) systems for primary-tooth root-canal preparation in terms of instrumentation time and amounts of dentin removed using micro-computed tomography (μCT) technology. Study Design: The study was conducted with 60 human primary mandibular second molar teeth divided into 3 groups according to instrumentation technique: Group I: SAF (n=20); Group II: K file (n=20); Group III; Profile (n=20). Teeth were embedded in acrylic blocks and scanned with a μCT scanner prior to instrumentation. All distal root canals were prepared up to size 30 for K file,.04/30 for Profile and 2 mm thickness, size 25 for SAF; instrumentation time was recorded for each tooth, and a second μCT scan was performed after instrumentation was complete. Amounts of dentin removed were measured using the three-dimensional images by calculating the difference in root-canal volume before and after preparation. Data was statistically analysed using the Kolmogorov-Smirnov and Kruskal-Wallis tests. Manual instrumentation (K file) resulted in significantly more dentin removal when compared to rotary instrumentation (Profile and SAF), while the SAF system generated significantly less dentin removal than both manual instrumentation (K file) and traditional rotary instrumentation (Profile) (psystems. Within the experimental conditions of the present study, the SAF seems as a useful system for root-canal instrumentation in primary molars because it removed less dentin than other systems, which is especially important for the relatively thin-walled canals of primary teeth, and because it involves less

  11. An overview of the NASA rotary engine research program

    Science.gov (United States)

    Meng, P. R.; Hady, W. F.

    1984-01-01

    A brief overview and technical highlights of the research efforts and studies on rotary engines over the last several years at the NASA Lewis Research Center are presented. The test results obtained from turbocharged rotary engines and preliminary results from a high performance single rotor engine were discussed. Combustion modeling studies of the rotary engine and the use of a Laser Doppler Velocimeter to confirm the studies were examined. An in-house program in which a turbocharged rotary engine was installed in a Cessna Skymaster for ground test studies was reviewed. Details are presented on single rotor stratified charge rotary engine research efforts, both in-house and on contract.

  12. Pneumatic Rotary Actuator Position Servo System Based on ADE-PD Control

    Directory of Open Access Journals (Sweden)

    Yeming Zhang

    2018-03-01

    Full Text Available In order to accurately control the rotation position of a pneumatic rotary actuator, the flow state of the gas and the motion state of the pneumatic rotary actuator in the pneumatic rotary actuator position servo system are analyzed in this paper. The mathematical model of the system and the experiment platform are established after that. An Adaptive Differential Evolution (ADE algorithm which adaptively ameliorates the scaling factor and crossover probability in the process of individual evolution is proposed and applied to the parameter optimization of PD controller. The experimental platform is used to compare the controller with Differential Evolution (DE algorithm and NCD-PID controller. Finally, the characteristics of the system are tested by increasing the inertial load. The experimental results illustrate that system using ADE-PD control strategy has greater position precision and faster response than using DE-PD and NCD-PID strategies, and shows great robustness.

  13. Design analysis and comparison between standard and rotary porting systems for IC engine

    Energy Technology Data Exchange (ETDEWEB)

    Palmisano, R.; Ng, H.D. [Concordia Univ., Montreal, PQ (Canada). Dept. of Mechanical and Industrial Engineering

    2009-07-01

    A method of improving the efficiency of an internal combustion engine was presented. The proposed design used a new sealing technology to optimize a rotary valve design. The design was compared with standard poppet porting system using a computer aided engineering (CAE) method. A double port cylinder configuration was used in order to allow continuous flow into the chamber and minimize the exposed surface area in the combustion chamber. The design also minimized distortion on the component when exposed to high condensation pressures. A transfer case was used to allow for easy adaptation of the configuration to a multi-cylinder engine. A mechanism dynamics extension (MDO) program was used to conduct dynamic analyses on the rotary and standard valve porting systems. The study showed that the poppet system required 62 times more torque than the new rotary valve design. It was concluded that further research is needed to examine the flow properties of both designs. 2 refs., 6 figs.

  14. Evaluation of Two New Electronic Apex-Locator-Controlled Handpieces Using a NiTi Rotary File: An In Vitro Study.

    Directory of Open Access Journals (Sweden)

    Kiumarz Nazarimoghadam

    2013-12-01

    Full Text Available The aim of this in-vitro study was to compare the accuracy of two new electronic apex-locator controlled handpieces (EALHs using the first rotary Mtwo file while rotating in the canal.A total of 36 extracted mandibular molar teeth were selected. The lengths of the mesio-buccal canals to the major foramina were measured directly using a size 10 K-file introduced in the canal until the tip was visible under a loupe and then 0.5 mm was subtracted from the recorded lengths as the actual working lengths (AWLs. Subsequently, the teeth were randomly assigned to two groups and embedded in an alginate model. Auto-stop function of the EALHs was preset at "0.5" mark and then electrical working lengths (EWLs in groups 1 and 2 were recorded by VDW GOLD and Dentaport ZX, respectively. Analysis of variance (ANOVA, 1-way and Tukey pairwise multiple comparison intervals (0.05 were used to compare the accuracy of the two electronic devices.For VDW GOLD, 61.1% of the measurements were within ±0.5 mm and 88.9% were within ±1 mm of the AWL. For Dentaport ZX, 88.9% of the measurements were within ±0.5 mm and 94.4% were within ±1mm of the AWL. There was no significant difference between AWLs and EWLs (p=0.466 for Dentaport ZX and p=0.283 for VDW Gold and between the accuracy of the two devices in determining the EWL (p=0.8.Both Dentaport ZX and VDW Gold were suitable for determining working length using a rotary file. To avoid over instrumenting the canal, we recommend setting the devices to automatically stop or reverse the rotary file at 1 mm level.

  15. Rotary retort for carbonizing bituminous materials

    Energy Technology Data Exchange (ETDEWEB)

    Meguin, A G; Muller, W

    1920-09-05

    A process of carbonizing bituminous materials, such as coal and oil shale at a low temperature in a rotary retort with simultaneous compressing the material especially of the semicoke formed that is characterized in that the material during the distillation through rapid rotation of the retort is exposed to the action of centrifugal force and thereby it is compressed.

  16. Numerical Modeling of Rotary Kiln Productivity Increase

    NARCIS (Netherlands)

    Romero-Valle, M.A.; Pisaroni, M.; Van Puyvelde, D.; Lahaye, D.J.P.; Sadi, R.

    2013-01-01

    Rotary kilns are used in many industrial processes ranging from cement manufacturing to waste incineration. The operating conditions vary widely depending on the process. While there are many models available within the literature and industry, the wide range of operating conditions justifies

  17. Precision Model for Microwave Rotary Vane Attenuator

    DEFF Research Database (Denmark)

    Guldbrandsen, Tom

    1979-01-01

    A model for a rotary vane attenuator is developed to describe the attenuator reflection and transmission coefficients in detail. All the parameters of the model can be measured in situ, i.e., without diassembling any part. The tranmission errors caused by internal reflections are calculated from ...

  18. Ka-band waveguide rotary joint

    KAUST Repository

    Yevdokymov, Anatoliy; Sirenko, Kostyantyn; Kryzhanovskiy, Volodymyr; Pazynin, Vadim

    2013-01-01

    The authors present a design of a waveguide rotary joint operating in Ka-band with central frequency of 33 GHz, which also acts as an antenna mount. The main unit consists of two flanges with a clearance between them; one of the flanges has three

  19. Deformation analysis of rotary combustion engine housings

    Science.gov (United States)

    Vilmann, Carl

    1991-01-01

    This analysis of the deformation of rotary combustion engine housings targeted the following objectives: (1) the development and verification of a finite element model of the trochoid housing, (2) the prediction of the stress and deformation fields present within the trochoid housing during operating conditions, and (3) the development of a specialized preprocessor which would shorten the time necessary for mesh generation of a trochoid housing's FEM model from roughly one month to approximately two man hours. Executable finite element models were developed for both the Mazda and the Outboard Marine Corporation trochoid housings. It was also demonstrated that a preprocessor which would hasten the generation of finite element models of a rotary engine was possible to develop. The above objectives are treated in detail in the attached appendices. The first deals with finite element modeling of a Wankel engine center housing, and the second with the development of a preprocessor that generates finite element models of rotary combustion engine center housings. A computer program, designed to generate finite element models of user defined rotary combustion engine center housing geometries, is also included.

  20. Influence of the rotary and/or oscillatory reciprocating systems in the morphological changes of narrow and curved molar root canals anatomy

    Directory of Open Access Journals (Sweden)

    Joedy Maria Costa Santa Rosa

    Full Text Available OBJECTIVE: This study evaluated four mechanized Endodontic systems, ProTaper Universal, K3 Endo, Twisted file (rotary and the oscillatory reciprocating system Endo - Eze TiLOS, in order to verify and measure alterations in original anatomy with deviations at cervical, medium and apical root canal thirds. MATERIAL AND METHOD: It was used MB root canals of 60 extract human lower molars, to produce a line of severe angles, according to the classification of Schneider. Samples were included in Ester vinyl resin, mounted in the Teflon Furnace, transversally sectioned at the cervical, middle and apical thirds, which were subsequently photographed using a digital camera Cyber Shot DSC-TX10,attached to an operating microscope 3101XY DFVasconcelos with 40× magnification in order to measure the anatomical transversal area of the root canal, using the software AutoCAD 2008, comparing pre and post-instrumentation. All samples assembled in the Furnace also were submitted to x-ray in a standardized way to enable the comparison of the angle of Schneider pre-and post-instrumentation. Once collected the data, they were compared statistically using the program BioEstat 5.0. RESULT: The analysis of the results showed that in the cervical third, rotary systems were more effective than Endo-Eze TiLOS System with statistically significant differences (p ≤ 0,05. Apical and middle third changes in anatomy were similar, but apically, the ProTaper system caused more deviations when comparing the angle of Schneider,and areas before and after instrumentation(p ≤ 0,05. CONCLUSION: It was concluded that all the systems caused alteration in the original anatomy of the root canal when parameters as angle of Schneider and areas before and after preparation were used.

  1. Microtomography-based comparison of reciprocating single-file F2 ProTaper technique versus rotary full sequence

    OpenAIRE

    Paqué, F; Zehnder, Matthias; De-Deus, G

    2011-01-01

    Introduction A preparation technique with only 1 single instrument was proposed on the basis of the reciprocating movement of the F2 ProTaper instrument. The present study was designed to quantitatively assess canal preparation outcomes achieved by this technique. Methods Twenty-five extracted human mandibular first molars with 2 separate mesial root canals were selected. Canals were randomly assigned to 1 of the 2 experimental groups: group 1, rotary conventional preparation by us...

  2. Stratified charge rotary engine combustion studies

    Science.gov (United States)

    Shock, H.; Hamady, F.; Somerton, C.; Stuecken, T.; Chouinard, E.; Rachal, T.; Kosterman, J.; Lambeth, M.; Olbrich, C.

    1989-07-01

    Analytical and experimental studies of the combustion process in a stratified charge rotary engine (SCRE) continue to be the subject of active research in recent years. Specifically to meet the demand for more sophisticated products, a detailed understanding of the engine system of interest is warranted. With this in mind the objective of this work is to develop an understanding of the controlling factors that affect the SCRE combustion process so that an efficient power dense rotary engine can be designed. The influence of the induction-exhaust systems and the rotor geometry are believed to have a significant effect on combustion chamber flow characteristics. In this report, emphasis is centered on Laser Doppler Velocimetry (LDV) measurements and on qualitative flow visualizations in the combustion chamber of the motored rotary engine assembly. This will provide a basic understanding of the flow process in the RCE and serve as a data base for verification of numerical simulations. Understanding fuel injection provisions is also important to the successful operation of the stratified charge rotary engine. Toward this end, flow visualizations depicting the development of high speed, high pressure fuel jets are described. Friction is an important consideration in an engine from the standpoint of lost work, durability and reliability. MSU Engine Research Laboratory efforts in accessing the frictional losses associated with the rotary engine are described. This includes work which describes losses in bearing, seal and auxillary components. Finally, a computer controlled mapping system under development is described. This system can be used to map shapes such as combustion chamber, intake manifolds or turbine blades accurately.

  3. Comparative study of fix-installed monitoring instruments and its application in detecting uncontrolled trafficking of radioactive materials at airports

    International Nuclear Information System (INIS)

    Pujol, L.; Suarez-Navarro, M. J.; Gonzalez-Gonzalez, J. A.; Garcia-Galludo, M.

    2010-01-01

    In this paper we analyze the response of three commercial equipment designed to detect illicit trafficking or inadvertent movement of radioactive materials at airports when carried by passengers. We compared three fix-installed instruments: APM (Bicron), GR-606 (Exploranium), and FHT-1372 (Thermo Eberline). In this initial evaluation conducted at the Laboratory of Nuclear engineering of the School of Civil Engineering, it was observed that the FHT-1372 introduced a fester detection response, sensitive and allowed the measurement of total dose rate and artificial dose rate. This equipment was installed at the exit from customs passenger of Barajas international airport operating for a period of 108 days in 2002 with a total number of 1,339,931 people. this period was divided into 5 sessions to establish suitable investigation levels to detect a possible incident of radioactive material, which was finally set at 110 nSv/h to total dose rate and 25 nSv/h for artificial dose rate. During this period 39 possible incidents were detected above the investigation level established, 5 of them with a value 10 times the environmental background of the room where the equipment was installed (about 90 nSv/h), and no level exceeded 100 μSv/h at 1 m distance, which is the limit for legal transport of radioactive materials from the International Atomic Energy Agency (IAEA). (Author) 17 refs.

  4. Comparative Assessment of the Heart's Functioning by Using the Akabane Test and Classical Methods of Instrumental Examination

    Directory of Open Access Journals (Sweden)

    Valery Muzhikov

    2017-06-01

    Full Text Available Acupuncture physicians have studied the application of reflexotherapy to cardiology. However, no one has investigated the connection of ancient Chinese diagnostic methods with modern tools. A total of 102 patients (54 men and 48 women with heart pathology, namely, sick-sinus syndrome, Wolff–Parkinson–White syndrome, and atrioventricular blockade, were studied using the usual instrumental methods (transesophageal electrophysiological study of the heart, echocardiography, after which they underwent Akabane thermopuncture testing as in traditional Chinese medicine. The results of cardio examination from one side of the Akabane test with that from the other side were compared by means of a multiple stepwise regression analysis. We revealed the effects on the characteristic pattern of acupuncture channel lesions inherent in a definite heart pathology, i.e., the most vulnerable acupuncture channel (AC, of such factors as disturbances of the contractile, conductive, or automatic heart functions, and changes in the chambers' size or circulation volume. Сhanges in the indices of the left and the right branches of these channels usually reflect the opposing natures of the changes in these indicators, which should be considered in reflexotherapy. The main value of the Akabane test along with the use of mathematical analysis lies in early, quick, and inexpensive detection of the above-mentioned heart disturbances.

  5. Update of development on the new Audi NSU rotary engine generation. [for application to aircraft engines

    Science.gov (United States)

    Vanbasshuysen, R.

    1978-01-01

    Rotary engines with a chamber volume of 750 cc as a two rotor automotive powerplant, called KKM 871 are described. This engine is compared to a 3 liter or 183 cubic inch, six-cylinder reciprocating engine. Emphasis is placed on exhaust emission control and fuel economy.

  6. Evaluation of the incidence of microcracks caused by Mtwo and ProTaper Next rotary file systems versus the self-adjusting file: A scanning electron microscopic study.

    Science.gov (United States)

    Saha, Suparna Ganguly; Vijaywargiya, Neelam; Saxena, Divya; Saha, Mainak Kanti; Bharadwaj, Anuj; Dubey, Sandeep

    2017-01-01

    To evaluate the incidence of microcrack formation canal preparation with two rotary nickel-titanium systems Mtwo and ProTaper Next along with the self-adjusting file system. One hundred and twenty mandibular premolar teeth were selected. Standardized access cavities were prepared and the canals were manually prepared up to size 20 after coronal preflaring. The teeth were divided into three experimental groups and one control group ( n = 30). Group 1: The canals were prepared using Mtwo rotary files. Group 2: The canals were prepared with ProTaper Next files. Group 3: The canals were prepared with self-adjusting files. Group 4: The canals were unprepared and used as a control. The roots were sectioned horizontally 3, 6, and 9 mm from the apex and examined under a scanning electron microscope to check for the presence of microcracks. The Pearson's Chi-square test was applied. The highest incidence of microcracks were associated with the ProTaper Next group, 80% ( P = 0.00), followed by the Mtwo group, 70% ( P = 0.000), and the least number of microcracks was noted in the self-adjusting file group, 10% ( P = 0.068). No significant difference was found between the ProTaper Next and Mtwo groups ( P = 0.368) while a significant difference was observed between the ProTaper Next and self-adjusting file groups ( P = 0.000) as well as the Mtwo and self-adjusting file groups ( P = 0.000). All nickel-titanium rotary instrument systems were associated with microcracks. However, the self-adjusting file system had significantly fewer microcracks when compared with the Mtwo and ProTaper Next.

  7. Development of a Computerized Multifunctional Form and Position Measurement Instrument

    International Nuclear Information System (INIS)

    Liu, P; Tian, W Y

    2006-01-01

    A model machine of multifunctional form and position measurement instrument controlled by a personal computer has been successfully developed. The instrument is designed in rotary table type with a high precision air bearing and the radial rotation error of the rotary table is 0.08 μm. Since a high precision vertical sliding carriage supported by an air bearing is used for the instrument, the straightaway motion error of the carriage is 0.3 μm/200 mm and the parallelism error of the motion of the carriage relative to the rotation axis of the rotary table is 0.4 μm/200 mm. The mathematical models have been established for assessing planar and spatial straightness, flatness, roundness, cylindricity, and coaxality errors. By radial deviation measurement, the instrument can accurately measure form and position errors of such workpieces as shafts, round plates and sleeves of medium or small dimensions with the tolerance grades mostly used in industry

  8. Apical Extrusion of Intracanal Bacteria following use of Two Engine-driven Instrumentation Techniques: An in vitro Study.

    Science.gov (United States)

    Mohammed, Niyaz; Noushad, M C; Balan, Biji; Dhanesh, N; Jayasheelan, Nishi; Revankar, Vanita D

    2016-11-01

    The aim of the present study was to compare in vitro the amount of debris extruded apically from extracted teeth, using Twisted files and ProTaper rotary during two different instrumentation systems. Forty-five human single-rooted mandibular premolar teeth were randomly divided into three groups and contaminated with Enterococcus faecalis. The teeth in experimental groups were instrumented until reaching the working length with ProTaper rotary instruments and Twisted files with XSmart and XSmart Dual groups. Debris extruded from the apical foramen was collected into glass vials and the amount of bacteria was calculated. The data obtained were analyzed using Kruskal-Wallis one-way analysis of variance and Mann-Whitney U tests, with p = 0.05 as the level for statistical significance. The XSmart Dual group extruded comparatively lesser bacteria compared to the XSmart group. Lesser amount of bacterial extrusion was seen when Twisted files were used compared to the ProTaper files (p endodontic care for our patients. The newer instrument designs, including noncutting tips, different cross sections, radial lands, and variable tapers, are better for the clinicians to improve working safety, to reduce the working time, and to create a greater flare within the preparations.

  9. Apically extruded dentin debris by reciprocating single-file and multi-file rotary system.

    Science.gov (United States)

    De-Deus, Gustavo; Neves, Aline; Silva, Emmanuel João; Mendonça, Thais Accorsi; Lourenço, Caroline; Calixto, Camila; Lima, Edson Jorge Moreira

    2015-03-01

    This study aims to evaluate the apical extrusion of debris by the two reciprocating single-file systems: WaveOne and Reciproc. Conventional multi-file rotary system was used as a reference for comparison. The hypotheses tested were (i) the reciprocating single-file systems extrude more than conventional multi-file rotary system and (ii) the reciprocating single-file systems extrude similar amounts of dentin debris. After solid selection criteria, 80 mesial roots of lower molars were included in the present study. The use of four different instrumentation techniques resulted in four groups (n = 20): G1 (hand-file technique), G2 (ProTaper), G3 (WaveOne), and G4 (Reciproc). The apparatus used to evaluate the collection of apically extruded debris was typical double-chamber collector. Statistical analysis was performed for multiple comparisons. No significant difference was found in the amount of the debris extruded between the two reciprocating systems. In contrast, conventional multi-file rotary system group extruded significantly more debris than both reciprocating groups. Hand instrumentation group extruded significantly more debris than all other groups. The present results yielded favorable input for both reciprocation single-file systems, inasmuch as they showed an improved control of apically extruded debris. Apical extrusion of debris has been studied extensively because of its clinical relevance, particularly since it may cause flare-ups, originated by the introduction of bacteria, pulpal tissue, and irrigating solutions into the periapical tissues.

  10. Intraoperative discomfort associated with the use of a rotary or reciprocating system: a prospective randomized clinical

    Directory of Open Access Journals (Sweden)

    Aline Cristine Gomes

    2017-05-01

    Full Text Available Objectives The aim of this randomized, controlled, prospective clinical study was to evaluate patients' intraoperative discomfort during root canal preparations in which either multi-file rotary (Mtwo or single-file reciprocating (Reciproc systems were used. Materials and Methods Fifty-five adult patients, aged between 25 and 69 years old, with irreversible pulpitis or pulp necrosis participated in this study. Either the mesiobuccal or the distobuccal canals for maxillary molars and either the mesiobuccal or the mesiolingual canals for mandibular molars were randomly chosen to be instrumented with Mtwo multi-file rotary or Reciproc single-file reciprocating systems. Immediately after each canal instrumentation under anesthesia, patient discomfort was assessed using a 1 - 10 visual analog scale (VAS, ranging from ‘least possible discomfort’ (1 to ‘greatest possible discomfort’ (10. The Wilcoxon signed-rank test was used to determine significant differences at p< 0.05. Results Little intraoperative discomfort was found in all cases. No statistically significant differences in intraoperative discomfort between the 2 systems were found (p = 0.660. Conclusions Root canal preparation with multi-file rotary or single-file reciprocating systems had similar and minimal effects on patients' intraoperative discomfort.

  11. Clinical outcome of root caries restorations using ART and rotary techniques in institutionalized elders

    Directory of Open Access Journals (Sweden)

    Alberto Carlos CRUZ GONZALEZ

    2016-01-01

    Full Text Available Abstract The aim of this study was to compare the clinical performance of root caries restorations after a six-month period using two methods, a conventional technique with rotary instruments and an atraumatic restorative technique (ART, in an institutionalized elderly population in the city of Bogotá, Colombia. Root caries represents a multifactorial, progressive, chronic lesion with softened, irregular and darkened tissue involving the radicular surface; it is highly prevalent in the elderly, especially in those who are physically or cognitively impaired. A quasi-experimental, double-blind, longitudinal study was carried out after cluster randomization of the sample. Two different experienced dentists, previously trained, performed the restorations using each technique. After six months, two new investigators performed a blind evaluation of the condition of the restorations. The results showed a significantly higher rate of success (92.9% using the conventional technique (p < 0.03. However, we concluded that ART may have been the preferred technique in the study population because 81% of those restorations survived or were successful during the observation period.

  12. 76 FR 11200 - Application(s) for Duty-Free Entry of Scientific Instruments

    Science.gov (United States)

    2011-03-01

    .... In particular, the instrument will be applied during the last step of the synthesis--the calcination... study high temperature combustion occurring in a rotary type engine called a ``wave disk engine.'' The...

  13. Environmental policy and economic efficiency: tradable permits versus regulatory instrument to control air pollution: a comparative approach USA/France

    International Nuclear Information System (INIS)

    Cros, Ch.

    1998-12-01

    The key issue of the thesis paradox of the weak implementation of economic instruments whereas 1) they are theoretically and also empirically considered as efficient; 2) the market imposes itself as the central reference to modem economies; and 3) economic efficiency is nowadays a legitimacy measure of public policies. Two different answers can be given: either theoretical analysis does not enable to explain the real economic efficiency of a political instrument, or environmental policies do not have economic efficiency as their main objective. The analysis take place in a context of a limited rationality and an inter-temporal consistency of public policies. The purpose is to understand the role of economic efficiency criteria during the adoption, building, and evolution of an environmental policy with an analytical point of view, and not a normative one. The institutional analysis of the American and the French pollution control policies, representative of the implementation of a trading permit system for the first, and of a regulatory instrument for the second, prove that the theoretical analysis of an instrument can not explain a real coordination, but only one organizational form among others. An institutional trajectory is the interpretation of policy instruments of policy instruments from 5 fundamental elements: the nature of the legitimacy of the policy; the nature of the regulator hypothesis on the information; the nature of the decision-making basis; the nature of the collective action. A coordination changes when the occurrence of an event moves one of the fundamental elements, and disorganizes the satisfying equilibrium of the agents. Then, the economic efficiency becomes a negotiation point. A political instrument is adopted for its own ability to solve a dysfunction without disrupting the coordination. (author)

  14. Micro- and macrostructural characterization of polyvinylpirrolidone rotary-spun fibers.

    Science.gov (United States)

    Sebe, István; Kállai-Szabó, Barnabás; Kovács, Krisztián Norbert; Szabadi, Enikő; Zelkó, Romána

    2015-01-01

    The application of high-speed rotary spinning can offer a useful mean for either preparation of fibrous intermediate for conventional dosage forms or drug delivery systems. Polyvinylpyrrolidone (PVP) and poly(vinylpyrrolidone-vinylacetate) (PVP VA) micro- and nanofibers of different polymer concentrations and solvent ratios were prepared with a high-speed rotary spinning technique. In order to study the influence of parameters that enable successful fiber production from polymeric viscous solutions, a complex micro- and macrostructural screening method was implemented. The obtained fiber mats were subjected to detailed morphological analysis using scanning electron microscope (SEM), and rheological measurements while the microstructural changes of fiber samples, based on the free volume changes, was analyzed by positron annihilation lifetime spectroscopy (PALS) and compared with their mechanical characteristics. The plasticizing effect of water tracked by ortho-positronium lifetime changes in relation to the mechanical properties of fibers. A concentration range of polyvinylpyrrolidone solutions was defined for the preparation of fibers of optimum fiber morphology and mechanical properties. The method enabled fiber formulation of advantageous functionality-related properties for further formulation of solid dosage forms.

  15. A study of the displacement of a Wankel rotary engine

    Science.gov (United States)

    Beard, J. E.; Pennock, G. R.

    1993-03-01

    The volumetric displacement of a Wankel rotary engine is a function of the trochoid ratio and the pin size ratio, assuming the engine has a unit depth and the number of lobes is specified. The mathematical expression which defines the displacement contains a function which can be evaluated directly and a normal elliptic integral of the second type which does not have an explicit solution. This paper focuses on the contribution of the elliptic integral to the total displacement of the engine. The influence of the elliptic integral is shown to account for as much as 20 percent of the total displacement, depending on the trochoid ratio and the pin size ratio. Two numerical integration techniques are compared in the paper, namely, the trapezoidal rule and Simpson's 1/3 rule. The bounds on the error, associated with each numerical method, are analyzed. The results indicate that the numerical method has a minimal effect on the accuracy of the calculated displacement for a practical number of integration steps. The paper also evaluates the influence of manufacturing tolerances on the calculated displacement and the actual displacement. Finally. a numerical example of the common three-lobed Wankel rotary engine is included for illustrative purposes.

  16. Grafton and local bone have comparable outcomes to iliac crest bone in instrumented single-level lumbar fusions.

    Science.gov (United States)

    Kang, James; An, Howard; Hilibrand, Alan; Yoon, S Tim; Kavanagh, Eoin; Boden, Scott

    2012-05-20

    Prospective multicenter randomized clinical trail. The goal of our 2-year prospective study was to perform a randomized clinical trial comparing the outcomes of Grafton demineralized bone matrix (DBM) Matrix with local bone with that of iliac crest bone graft (ICBG) in a single-level instrumented posterior lumbar fusion. There has been extensive research and development in identifying a suitable substitute to replace autologous ICBG that is associated with known morbidities. DBMs are a class of commercially available grafting agents that are prepared from allograft bone. Many such products have been commercially available for clinical use; however, their efficacy for spine fusion has been mostly based on anecdotal evidence rather than randomized controlled clinical trials. Forty-six patients were randomly assigned (2:1) to receive Grafton DBM Matrix with local bone (30 patients) or autologous ICBG (16 patients). The mean age was 64 (females [F] = 21, males [M] = 9) in the DBM group and 65 (F = 9, M = 5) in the ICBG group. An independent radiologist evaluated plain radiographs and computed tomographic scans at 6-month, 1-year, and 2-year time points. Clinical outcomes were measured using Oswestry Disability Index (ODI) and Medical Outcomes Study 36-Item Short Form Health Survey. Forty-one patients (DBM = 28 and ICBG = 13) completed the 2-year follow-up. Final fusion rates were 86% (Grafton Matrix) versus 92% (ICBG) (P = 1.0 not significant). The Grafton group showed slightly better improvement in ODI score than the ICBG group at the final 2-year follow-up (Grafton [16.2] and ICBG [22.7]); however, the difference was not statistically significant (P = 0.2346 at 24 mo). Grafton showed consistently higher physical function scores at 24 months; however, differences were not statistically significant (P = 0.0823). Similar improvements in the physical component summary scores were seen in both the Grafton and ICBG groups. There was a statistically significant greater mean

  17. Rotary Mode Core Sample System availability improvement

    International Nuclear Information System (INIS)

    Jenkins, W.W.; Bennett, K.L.; Potter, J.D.; Cross, B.T.; Burkes, J.M.; Rogers, A.C.

    1995-01-01

    The Rotary Mode Core Sample System (RMCSS) is used to obtain stratified samples of the waste deposits in single-shell and double-shell waste tanks at the Hanford Site. The samples are used to characterize the waste in support of ongoing and future waste remediation efforts. Four sampling trucks have been developed to obtain these samples. Truck I was the first in operation and is currently being used to obtain samples where the push mode is appropriate (i.e., no rotation of drill). Truck 2 is similar to truck 1, except for added safety features, and is in operation to obtain samples using either a push mode or rotary drill mode. Trucks 3 and 4 are now being fabricated to be essentially identical to truck 2

  18. Hole history, rotary hole DC-3

    International Nuclear Information System (INIS)

    1977-10-01

    Purpose of hole DC-3 was to drill into the Umtanum basalt flow using both conventional rotary and core drilling methods. The borehole is to be utilized for geophysical logging, future hydrological testing, and the future installation of a borehole laboratory for long-term pressure, seismic, and moisture migration or accumulation recording in the Umtanum basalt flow in support of the Basalt Waste Isolation Program. Hole DC-3 is located east of the 200 West barricaded area on the Hanford reservation

  19. Control of Rotary Cranes Using Fuzzy Logic

    Directory of Open Access Journals (Sweden)

    Amjed A. Al-mousa

    2003-01-01

    Full Text Available Rotary cranes (tower cranes are common industrial structures that are used in building construction, factories, and harbors. These cranes are usually operated manually. With the size of these cranes becoming larger and the motion expected to be faster, the process of controlling them has become difficult without using automatic control methods. In general, the movement of cranes has no prescribed path. Cranes have to be run under different operating conditions, which makes closed-loop control attractive.

  20. The Wankel rotary engine a history

    CERN Document Server

    Hege, John B

    2007-01-01

    "It stands apart from the crowd as the only history of the Wankel rotary engine that brings the story into the 21st Century"--SAH Journal; "this book continues to excel...terrific...technophiles will love this"--Hemmings Motor News; "excellent"--Hemmings Sports & Exotic Car; "a complete history...guaranteed to delight"--Old Cars Weekly; "definitive…a must-read"--Choice; "informative"--SciTech Book News; "goes a long way to explaining everything"--The Automobile. This complete and well-illustrated account traces the full history of the Wankel rotary engine and its use in various cars, motorcycles, snowmobiles and other applications. It clearly explains the working of the engine and the technical challenges it presented--the difficulty of designing effective and durable seals, early emissions troubles, high fuel consumption, and others. The work done by several companies to overcome these problems is described in detail, as are the economic and political troubles that nearly killed the rotary in the 19...

  1. Rotary-Atomizer Electric Power Generator

    Science.gov (United States)

    Nguyen, Trieu; Tran, Tuan; de Boer, Hans; van den Berg, Albert; Eijkel, Jan C. T.

    2015-03-01

    We report experimental and theoretical results on a ballistic energy-conversion method based on a rotary atomizer working with a droplet acceleration-deceleration cycle. In a rotary atomizer, liquid is fed onto the center of a rotating flat surface, where it spreads out under the action of the centrifugal force and creates "atomized" droplets at its edge. The advantage of using a rotary atomizer is that the centrifugal force exerted on the fluid on a smooth, large surface is not only a robust form of acceleration, as it avoids clogging, but also easily allows high throughput, and produces high electrical power. We successfully demonstrate an output power of 4.9 mW and a high voltage up to 3120 V. At present, the efficiency of the system is still low (0.14%). However, the conversion mechanism of the system is fully interpreted in this paper, permitting a conceptual understanding of system operation and providing a roadmap for system optimization. This observation will open up a road for building power-generation systems in the near future.

  2. Elimination of intracanal infection in dogs' teeth with induced periapical lesions after rotary instrumentation: influence of different calcium hydroxide pastes Eliminação da infecção intracanal em dentes de cães com lesões periapicais induzidas após instrumentação automatizada: influência de diferentes pastas de hidróxido de cálcio

    Directory of Open Access Journals (Sweden)

    Janir Alves Soares

    2006-06-01

    Full Text Available The aim of this study was to evaluate the antiseptic efficacy of rotary instrumentation associated with calcium hydroxide-based pastes prepared with different vehicles and antiseptics. Chronic periapical lesions were experimentally induced in 72 premolar root canals of four dogs. Under controlled asepsis, after initial microbiological sampling (A1, the root canals were instrumented using the ProFile system in conjunction with 5.25% sodium hypochlorite and the intracanal medication was placed. Four experimental groups were formed according to the pastes used: group 1- Calen (n=18, group 2- Calen+CPMC (n=20, group 3- Ca(OH2 p.a.+ anaesthetic solution (n=16 and group 4- Ca(OH2 p.a.+ 2% chlorhexidine digluconate (n=18. After 21 days, the pastes were removed; the canals were emptied and 96 hours later a second microbiological sample was obtained (A2. The incidence of positive microbiological cultures and the number of cfus in stages A1 and A2 were compared statistically by the Wilcoxon test while the influence of the different treatments in intracanal infection was evaluated by Kruskal-Wallis test at 5% significance level (pO objetivo deste estudo foi avaliar a eficácia anti-séptica da instrumentação rotatória associada às pastas à base de hidróxido de cálcio [Ca(OH2] contendo diferentes veículos e anti-sépticos. Lesões periapicais crônicas foram experimentalmente induzidas em 72 canais radiculares de pré-molares de 4 cães. Sob controlada assepsia, após amostras microbiológicas iniciais (A1, fez-se a instrumentação com o sistema ProFile coadjuvado pela solução de hipoclorito de sódio a 5,25%, seguido de medicação intracanal. Em função das pastas utilizadas obtiveram-se 4 grupos: grupo 1- Calen (n=18, grupo 2- Calen+PMCC (n=20, grupo 3- Ca(OH2 p.a.+ solução anestésica (n=16 e grupo 4- Ca(OH2 p.a.+ solução de digluconato de clorexidina a 2% (n=18. Transcorridos 21 dias, removeram-se as pastas, deixando os canais

  3. Analysis of Apex Seal Friction Power Loss in Rotary Engines

    Science.gov (United States)

    Handschuh, Robert F.; Owen, A. Karl

    2010-01-01

    An analysis of the frictional losses from the apex seals in a rotary engine was developed. The modeling was initiated with a kinematic analysis of the rotary engine. Next a modern internal combustion engine analysis code was altered for use in a rotary engine to allow the calculation of the internal combustion pressure as a function of rotor rotation. Finally the forces from the spring, inertial, and combustion pressure on the seal were combined to provide the frictional horsepower assessment.

  4. Working length changes in curved canals after coronal flaring by using rotary files and hand file: An in vitro study.

    Science.gov (United States)

    Kumar, Rahul; Khambete, Neha; Patil, Suvarna; Hoshing, Upendra; Medha, Ashish; Shetty, Roshan

    2013-09-01

    This in vitro investigation examined the effect of early coronal flaring (CF) and late CF on the working length (WL) in curved root canals. The objective of this study was to determine if canal length is altered as a result of CF in curved canals of molar roots. The conditions compared were combinations of (a) stainless steel hand files using Gates Glidden (G. G.) drills (SS) versus nickel-titanium rotary files (Ni-Ti); and (b) early CF (flaring completed before WL determination) versus late CF (flaring completed after WL determination). Selected were 90 canals of extracted maxillary or mandibular first molars (mesial root of mandibular molars and the mesiobuccal root of the maxillary molars) from three groups. CF was accomplished for the SS group using G. G. drills and for the Ni-Ti group using rotary ProTaper and Hero Shaper files. WL was determined by a digital vernier caliper before CF, immediately after CF, and again after canal preparation. A repeated measures analysis of variance (ANOVA) test and a Tukey's multiple prosthoc test were used for this study. Results indicated that WL decreased for all canals as a result of canal preparation. The mean decrease in WL was significantly greater for the SS group (-0.77 ± 0.42 mm) than for the Ni-Ti groups (-0.33 mm ± 0.44). Less change in WL occurred in all groups when initial WL was determined after CF. WL in curved canals consistently decreases during the course of instrumentation. Clinician should keep this in mind for better treatment outcome.

  5. Evaluation of apically extruded debris during removal of gutta-percha and ResilonTM using different instrumentation techniques

    Directory of Open Access Journals (Sweden)

    Pešić Dragana

    2018-01-01

    Full Text Available Background/Aim. Apical extrusion of material is considered as one of the very important factor for endodontic treatment success. Microorganisms, necrotic tissue, filling material and irrigants, which can be extruded apically during endodontic retreatment, may jeopardize the success of the therapy. The aim of this in vitro study was to quantitatively evaluate the amount of apically extruded debris during endodontic retreatment of teeth obturated with two different materials, using one hand and three rotary instrumentation techniques. Methods. Ninety-six extracted single-rooted teeth were endodontically treated and enlarged to size 40 using BioRaCe system, and then randomly divided into 8 groups of 12 specimens each. Half of the specimens were obturated with gutta-percha and AH Plus® sealer and another half with RealSeal SE system, using lateral condensation technique. Retreatment was performed using: Hedström files; ProFile rotary files; ProTaper Retreatment system and D-RaCe system. Apically extruded debris was collected in pre-weighed Eppendorf tubes and evaluated using an electronic microbalance. Data were analyzed statistically using t-test and analysis of variance. Results. In the AH Plus/gutta-percha group, all tested rotary instruments gave significantly less extruded debris compared with Hedström files (p < 0.05. In theRealSeal group, there was significant difference between DRaCe and Hedström instruments (p < 0.05. Conclusion. All retreatment techniques resulted in apical extrusion. DRaCe system produced significantly less extruded debris compared to hand files. No significant difference was found when comparing two instruments specially designed for retreatment: D-RaCe and ProTaper systems.

  6. Tallinna Rotary klubi valis aasta politseiniku ja narkokoera

    Index Scriptorium Estoniae

    2006-01-01

    Tallinna Rotary klubi autasustas parima narkopolitseiniku preemiaga Lõuna politseiprefektuuri narkokuritegude talituse vaneminspektorit Jarek Pavlihhinit ning parima narkokoera tiitliga vene spanjelit Allrighti

  7. The Rotary Combustion Engine: a Candidate for General Aviation. [conferences

    Science.gov (United States)

    1978-01-01

    The state of development of the rotary combustion engine is discussed. The nonturbine engine research programs for general aviation and future requirements for general aviation powerplants are emphasized.

  8. Detailed characterization of a Comparative Reactivity Method (CRM) instrument for ambient OH reactivity measurements: experiments vs. modeling

    Science.gov (United States)

    Michoud, Vincent; Locoge, Nadine; Dusanter, Sébastien

    2015-04-01

    The Hydroxyl radical (OH) is the main daytime oxidant in the troposphere, leading to the oxidation of Volatile Organic Compounds (VOCs) and the formation of harmful pollutants such as ozone (O3) and Secondary Organic Aerosols (SOA). While OH plays a key role in tropospheric chemistry, recent studies have highlighted that there are still uncertainties associated with the OH budget, i.e the identification of sources and sinks and the quantification of production and loss rates of this radical. It has been demonstrated that ambient measurements of the total OH loss rate (also called total OH reactivity) can be used to identify and reduce these uncertainties. In this context, the Comparative Reactivity Method (CRM), developed by Sinha et al. (ACP, 2008), is a promising technique to measure total OH reactivity in ambient air and has already been used during several field campaigns. This technique relies on monitoring competitive reactions of OH with ambient trace gases and a reference compound (pyrrole) in a sampling reactor to derive ambient OH reactivity. However, this technique requires a complex data processing chain that has yet to be carefully investigated in the laboratory. In this study, we present a detailed characterization of a CRM instrument developed at Mines Douai, France. Experiments have been performed to investigate the dependence of the CRM response on humidity, ambient NOx levels, and the pyrrole-to-OH ratio inside the sampling reactor. Box modelling of the chemistry occurring in the reactor has also been performed to assess our theoretical understanding of the CRM measurement. This work shows that the CRM response is sensitive to both humidity and NOx, which can be accounted for during data processing using parameterizations depending on the pyrrole-to-OH ratio. The agreement observed between laboratory studies and model results suggests a good understanding of the chemistry occurring in the sampling reactor and gives confidence in the CRM

  9. Pre-bent instruments used in single-port laparoscopic surgery versus conventional laparoscopic surgery: comparative study of performance in a dry lab.

    Science.gov (United States)

    Miernik, Arkadiusz; Schoenthaler, Martin; Lilienthal, Kerstin; Frankenschmidt, Alexander; Karcz, Wojciech Konrad; Kuesters, Simon

    2012-07-01

    Different types of single-incision laparoscopic surgery (SILS) have become increasingly popular. Although SILS is technically even more challenging than conventional laparoscopy, published data of first clinical series seem to demonstrate the feasibility of these approaches. Various attempts have been made to overcome restrictions due to loss of triangulation in SILS by specially designed SILS-specific instruments. This study involving novices in a dry lab compared task performances between conventional laparoscopic surgery (CLS) and single-port laparoscopic surgery (SPLS) using newly designed pre-bent instruments. In this study, 90 medical students without previous experience in laparoscopic techniques were randomly assigned to undergo one of three procedures: CLS, SPLS using two pre-bent instruments (SPLS-pp), or SPLS using one pre-bent and one straight laparoscopic instrument (SPLS-ps). In the dry lab, the participants performed four typical laparoscopic tasks of increasing difficulty. Evaluation included performance times or number of completed tasks within a given time frame. All performances were videotaped and evaluated for unsuccessful attempts and unwanted interactions of instruments. Using subjective questionnaires, the participants rated difficulties with two-dimensional vision and coordination of instruments. Task performances were significantly better in the CLS group than in either SPLS group. The SPLS-ps group showed a tendency toward better performances than the SPLS-pp group, but the difference was not significant. Video sequences and participants` questionnaires showed instrument interaction as the major problem in the single-incision surgery groups. Although SILS is feasible, as shown in clinical series published by laparoscopically experienced experts, SILS techniques are demanding due to restrictions that come with the loss of triangulation. These can be compensated only partially by currently available SILS-designed instruments. The future of

  10. Development of Rotary-Wing UAS for Use in Atmospheric Sensing of Near-Storm Environments

    Science.gov (United States)

    Greene, B. R.; Chilson, P. B.; Salazar-Cerreno, J.; Duthoit, S.; Doyle, B.; Wolf, B.; Segales, A.; Fiebrich, C. A.; Waugh, S.; Fredrickson, S.; Oncley, S.; Tudor, L.; Semmer, S.

    2017-12-01

    The capabilities of small unmanned aircraft systems (sUAS) to make atmospheric observations is rapidly being realized as a means to collect previously unobtainable observations in the lowest part of Earth's atmosphere. However, in order for these systems to provide meaningful kinematic and thermodynamic data, it is imperative to establish an understanding of the strengths and limitations of the sensors and retrieval algorithms implemented in both controlled and realistic conditions. This initial objective is comprised of two experimental stages, the first of which is calibration of thermodynamic sensors against references from the Oklahoma Mesonet and the National Center for Atmospheric Research in order to understand their quasi-ideal response characteristics. Furthermore, efforts have been made to calculate horizontal wind fields using Euler angles derived from the sUAS's autopilot. The second stage is validation of these sensor performances once mounted onto a rotary-wing sUAS by comparing measurements with instrumented towers, radiosondes, and other sUAS. It appears that these measurements are robust provided that instrument packages are mounted such that they receive adequate air flow and proper solar shielding. Moreover, experiments to locate this optimal location have been performed, and involved systematically displacing the sensors and wind probe underneath the rotor wash in an isolated chamber using a linear actuator. Once a platform's atmospheric sensing capabilities are optimized, its utility has been proven in applications from turbulence to providing forecasters with quasi-real time profiles in convective environments deemed by the Storm Prediction Center to be of highest risk for severe thunderstorms. After addressing the development of platforms operated by the University of Oklahoma, results from recent field campaigns, Collaboration Leading Operational UAS Development for Meteorology and Atmospheric Physics (CLOUD-MAP) and Environmental Profiling

  11. A study of particle motion in rotary dryer

    Directory of Open Access Journals (Sweden)

    M. H. Lisboa

    2007-09-01

    Full Text Available The purpose of this work was to study the performance of a rotary dryer in relation to number of flights. In this work an equationing was proposed to calculate the area used by the solids in two-segment flights of with any angle between the segments. From this area, the flight holdup and the length of fall of the particles were calculated for different angle positions and the results obtained were compared to experimental values. The results show an increase in dryer efficiency with the increase in number of flights up to a limit value, for ideal operational conditions. The experimental data on average residence time were compared to results obtained by calculations using equations proposed in the literature. The equation proposed for predicting flight holdup and length of fall of particles generated very accurate estimations.

  12. A dynamic analysis of rotary combustion engine seals

    Science.gov (United States)

    Knoll, J.; Vilmann, C. R.; Schock, H. J.; Stumpf, R. P.

    1984-01-01

    Real time work cell pressures are incorporated into a dynamic analysis of the gas sealing grid in Rotary Combustion Engines. The analysis which utilizes only first principal concepts accounts for apex seal separation from the crochoidal bore, apex seal shifting between the sides of its restraining channel, and apex seal rotation within the restraining channel. The results predict that apex seals do separate from the trochoidal bore and shift between the si