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

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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.

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

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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.

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

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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.

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

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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.

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

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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.

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

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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.

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

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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.

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

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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.

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.

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

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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.

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

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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.

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

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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

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

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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.

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

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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.

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

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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

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

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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

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

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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.

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

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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

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.

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

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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.

Mechanical and Metallurgical Properties of Various Nickel-Titanium Rotary Instruments

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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...

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

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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

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

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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

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.

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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.

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

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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.

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

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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.

Comparison of removed dentin thickness with hand and rotary instruments

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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

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

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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.

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

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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.

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

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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.

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

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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.

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

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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.

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

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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.

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

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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.

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

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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.

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

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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

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

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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.

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

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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.

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

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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

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

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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.

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

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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.

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

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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

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

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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.

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

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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.

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

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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.

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

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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

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

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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.

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

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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.

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

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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.

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

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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.

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

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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.

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

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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.

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

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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.

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.

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

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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

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

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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.

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

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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.

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

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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.

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

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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

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

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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.

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

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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.

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

Directory of Open Access Journals (Sweden)

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.

[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.

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

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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.

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.

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

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.

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.

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.

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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.

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

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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

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

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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.

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

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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

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

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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.

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

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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.

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

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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.

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

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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

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

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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).

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

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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

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

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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.

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...

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

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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.

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

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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.

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

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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.

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

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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.

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

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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.

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.

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

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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.

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

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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.

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

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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

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

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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.

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

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.

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

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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

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...

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

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.

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.

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.

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...

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...

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.

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

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.

[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.

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.

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

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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.

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

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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.

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

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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.

Rotary Transformer

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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.

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

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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].

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

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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.

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

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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.

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.

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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.

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

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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.

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

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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

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

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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.

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

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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.

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

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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.

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

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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.

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

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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.

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

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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

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

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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.

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

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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.

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

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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.

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

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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.

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

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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

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

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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.

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

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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.

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

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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.

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.

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

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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.

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...

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

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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.

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

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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.

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

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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.

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.

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.

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

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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.

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.

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

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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

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

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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.

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.

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

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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

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.

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.

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...

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

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.

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

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

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.

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.

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

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.

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.

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

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.

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

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.

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.

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.

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

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.

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.

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.

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.

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 ...

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.

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.

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)

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

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.

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%.

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

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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.

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

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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.

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

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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.

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

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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.

An Improved Rotary Interpolation Based on FPGA

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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.

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

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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

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

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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.

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

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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.

Rotary endodontics in primary teeth – A review

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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...

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

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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.

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

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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.

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

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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.

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.

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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.

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

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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.

Experimental analysis of IMEP in a rotary combustion engine. [Indicated Mean Effective Pressure

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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.

[Comparison of effectiveness and safety between Twisted File technique and ProTaper Universal rotary full sequence based on micro-computed tomography].

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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.

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

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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.

Evaluation of the Self-Adjusting File system (SAF) for the instrumentation of primary molar root canals: a micro-computed tomographic study.

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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

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

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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...

A quantitative analysis of rotary, ultrasonic and manual techniques to treat proximally flattened root canals

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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.

Rotary and radial forcing effects on center-of-mass locomotion dynamics.

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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

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 ...

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

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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.

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

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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.

Safety Assessment of Two Hybrid Instrumentation Techniques in a Dental Student Endodontic Clinic: A Retrospective Study.

Science.gov (United States)

Coelho, Marcelo Santos; Card, Steven John; Tawil, Peter Zahi

2017-03-01

The aim of this study was to retrospectively assess the safety potential of a hybrid technique combining nickel-titanium (NiTi) reciprocating and rotary instruments by third- and fourth-year dental students in the predoctoral endodontics clinic at one U.S. dental school. For the study, 3,194 root canal treatments performed by 317 dental students from 2012 through 2015 were evaluated for incidence of ledge creation and instrument separation. The hybrid reciprocating and rotary technique (RRT) consisted of a glide path creation with stainless steel hand files up to size 15/02, a crown down preparation with a NiTi reciprocating instrument, and an apical preparation with NiTi rotary instruments. The control was a traditional rotary and hand technique (RHT) that consisted of the same glide path procedure followed by a crown down preparation with NiTi rotary instruments and an apical preparation with NiTi hand instruments. The results showed that the RHT technique presented a rate of ledge creation of 1.4% per root and the RRT technique was 0.5% per root (protary technique for root canal instrumentation by these dental students provided good safety. This hybrid technique offered a low rate of ledge creation along with no NiTi instrument separation.

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

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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%.

Cleaning capacity promoted by motor-driven or manual instrumentation using ProTaper Universal system: Histological analysis.

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da Frota, Matheus Franco; Filho, Idomeo Bonetti; Berbert, Fábio Luiz Camargo Villela; Sponchiado, Emilio Carlos; Marques, André Augusto Franco; Garcia, Lucas da Fonseca Roberti

2013-01-01

The aim of this study was to assess the cleaning capacity of the Protaper system using motor-driven or manual instrumentation. Ten mandibular molars were randomly separated into 2 groups (n = 5) according to the type of instrumentation performed, as follows: Group 1 - instrumentation with rotary nickel-titanium (Ni-Ti) files using ProTaper Universal System (Dentsply/Maillefer); and, Group 2 - instrumentation with Ni-Ti hand files using ProTaper Universal (Dentsply-Maillefer). Afterwards, the teeth were sectioned transversely and submitted to histotechnical processing to obtain histological sections for microscopic evaluation. The images were analyzed by the Corel Photo-Paint X5 program (Corel Corporation) using an integration grid superimposed on the image. Statistical analysis (U-Mann-Whitney - P < 0.05) demonstrated that G1 presented higher cleaning capacity when compared to G2. The rotary technique presented better cleaning results in the apical third of the root canal system when compared to the manual technique.

Piezoelectric Versus Conventional Rotary Techniques for Impacted Third Molar Extraction

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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

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

Apical extrusion of debris in four different endodontic instrumentation systems: A meta-analysis.

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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.

Evaluation of Root Canal Cleaning and Shaping Efficacy of Three Engine-driven Instruments: SafeSider, ProTaper Universal and Lightspeed LSX.

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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.

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.

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.

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.

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.

Perawatan Satu\tKunjungan\tpada\tPremolar Pertama Atas Menggunakan Protaper Rotary dan Restorasi Resin Komposit

Directory of Open Access Journals (Sweden)

Sherli Diana

2013-06-01

Full Text Available Preparasi kemomekanik pada saluran akar meliputi instrumentasi mekanis dan irigasi antibakteri yang secara prinsip dapat langsung mengeliminasi mikroorganisme pada sistem saluran akar. sejak diperkenalkan pada tahun 1988, instrumen rotary nikel-titanium (niti telah digunakan secara umum dalam perawatan endodontik karena kemampuannya membentuk saluran akar dengan prosedur komplikasi yang minimal. Tujuan dari laporan kasus ini adalah untuk memaparkan perawatan saluran akar satu kunjungan menggunakan protaper rotary dan restorasi resin komposit gigi premolar. Penderita pria 21 tahun datang ke RSGM Prof. Soedomo UGM Yogyakarta mengeluhkan gigi belakang atas kiri yang berlubang tapi tidak sakit dan pasien ingin  dirawat.Gigi  Premolar satu atas  kiri terdapat kavitas disto oklusal dengan pulpa terbuka. Pemeriksan objektif pada gigi 24 sondasi, perkusi, palpasi, dan tes termal menunjukkan hasil negatif.Pemeriksaan radiografis tidak terdapat lesi, lamina dura tidak terputus dan saluran akar jelas dan lurus. Pada kasus ini dilakukan perawatan saluran akar dengan menggunakan ProTaper rotary ( X-Smart, Dentsply. Pasca perawatan saluran akar, gigi premolar satu atas kiri dilakukan tumpatan resin komposit kelas II.Hasil evaluasi klinik saat kontrol tidak ada keluhan rasa sakit, pemeriksaan objektif juga tidak ada rasa sakit, warna gigi serasi dengan warna gigi tetangga.prognosis pada kasus ini baik dan tidak ada keluhan. Kesimpulan paska perawatan saluran akar satu kunjungan dengan instrumenrotary, tidak terdapat keluhan.Penggunaan Instrumen rotary Nikel-Titanium (NiTi sangat flexible dengan prosedur komplikasi yang minimal, dan hemat waktu. One Visit Treatment of Upper Premolar Tooth Using Rotary Protaper and Composite Resin Restoration. Chemomechanical preparation for root canal including mechanic instrumentation and anti-bacterial irrigation principally could eliminate microorganisms in root canal system. Many instruments and techniques have been

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

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

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

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.

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

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.

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%.

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.

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.

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.

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.

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.

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.

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.

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.

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

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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.

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.

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.

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.

Comparison of working length control consistency between hand K-files and Mtwo NiTi rotary system.

Science.gov (United States)

Krajczár, Károly; Varga, Enikő; Marada, Gyula; Jeges, Sára; Tóth, Vilmos

2016-04-01

The purpose of this study was to investigate the consistency of working length control between hand instrumentation in comparison to engine driven Mtwo nickel-titanium rotary files. Forty extracted maxillary molars were selected and divided onto two parallel groups. The working lengths of the mesiobuccal root canals were estimated. The teeth were fixed in a phantom head. The root canal preparation was carried out group 1 (n=20) with hand K-files, (VDW, Munich, Germany) and group 2 (n=20) with Mtwo instruments (VDW, Munich, Germany). Vestibulo-oral and mesio-distal directional x-ray images were taken before the preparation with #10 K-file, inserted into the mesiobuccal root canal to the working length, and after preparation with #25, #30 and #40 files. Working lenght changes were detected with measurements between the radiological apex and the instrument tips. In the Mtwo group a difference in the working competency (protary files. Mtwo NiTi rotary file did therefore proved to be more accurate in comparison to the conventional hand instrumentation. Working length, Mtwo, nickel-titanium, hand preparation, engine driven preparation.

Evaluation of apically extruded debris during removal of gutta-percha and ResilonTM using different instrumentation techniques

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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.

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.

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.

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.

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.

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

Canal preparation with nickel-titanium or stainless steel instruments without the risk of instrument fracture: preliminary observations

OpenAIRE

Ghassan Yared

2015-01-01

This report introduces a novel technique that allows a safe and predictable canal negotiation, creation of a glide path and canal preparation with reciprocating nickel-titanium or stainless steel engine-driven instruments in canals where the use of rotary and the newly developed reciprocating instruments is contraindicated. In this novel technique, the instruments are used in reciprocating motion with very small angles. Hand files are not used regardless of the complexity of the canal anatomy...

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.

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.

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.

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.

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

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.

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...

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.

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.

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.

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

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.

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.

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.

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.

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...

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

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

Canal preparation with nickel-titanium or stainless steel instruments without the risk of instrument fracture: preliminary observations

Directory of Open Access Journals (Sweden)

Ghassan Yared

2015-02-01

Full Text Available This report introduces a novel technique that allows a safe and predictable canal negotiation, creation of a glide path and canal preparation with reciprocating nickel-titanium or stainless steel engine-driven instruments in canals where the use of rotary and the newly developed reciprocating instruments is contraindicated. In this novel technique, the instruments are used in reciprocating motion with very small angles. Hand files are not used regardless of the complexity of the canal anatomy. It also allows achieving predictable results in canal negotiation and glide path creation in challenging canals without the risk of instrument fracture.

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...

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.

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.

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

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.

In vitro evaluation of the effectiveness of ProTaper universal rotary retreatment system for gutta-percha removal with or without a solvent.

Science.gov (United States)

Takahashi, Cristiane Midori; Cunha, Rodrigo Sanches; de Martin, Alexandre Sigrist; Fontana, Carlos Eduardo; Silveira, Cláudia Fernandes M; da Silveira Bueno, Carlos Eduardo

2009-11-01

Effective removal of gutta-percha in endodontic retreatment is a significant factor to ensure a favorable outcome from failed procedures. The purpose of this study was to evaluate the efficacy of a nickel-titanium rotary instrument system with or without a solvent versus stainless steel hand files for gutta-percha removal. Forty extracted human maxillary anterior teeth were prepared and filled. They were divided into 4 groups: Gates-Glidden and K-files, Gates-Glidden and K-files with chloroform, ProTaper Universal rotary retreatment system, and ProTaper Universal rotary retreatment system with chloroform. The operating time was recorded. The teeth were longitudinally sectioned and photographed. The images were analyzed and the filling remnants were quantified by using the IMAGE TOOL software. With Kruskall-Wallis test, statistical analysis showed that there was no significant difference between the techniques in regard to the amount of the endodontic filling remnants (P ProTaper Universal rotary retreatment system was faster than the hand files (P ProTaper Universal rotary retreatment system without chloroform was faster.

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.

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.

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.

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

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. ...

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

Science.gov (United States)

Ghogre, Priyanka; Chourasia, Hemant Ramesh; Agarwal, Manish; Singh, M P; Gurav, Sandeep; Ghogre, Rahul

2015-01-01

The aim of this study was to evaluate the number of intracanal bacteria extruded apically during root canal preparation using rotary ProTaper, K3XF, twisted, and hand K-file system. Seventy extracted single-rooted human mandibular premolar teeth were used. Access cavities were prepared and the teeth were mounted in glass vials. Root canals were then contaminated with a pure culture of Enterococcus faecalis (ATCC 29212) and incubated at 37°C for 24 h. The contaminated roots were divided into four experimental groups of 15 teeth each and one control group of 10 teeth. Group 1: ProTaper; Group 2: K3XF; Group 3: Twisted file; Group 4: Hand K-file; Group 5: Control group. Bacteria extruded from the apical foramen during instrumentation were collected into vials. The microbiological samples were incubated in culture media for 24 h. Colonies of bacteria were counted and the results were given as number of colony-forming units (CFU)/ml. The obtained data were analyzed using the Kruskal-Wallis one-way analysis of variance and Mann-Whitney U-tests. There was a significant difference between the rotary and hand instrumentation system related to the apically extruded intracanal bacteria. 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.

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.

Quantitative evaluation of apically extruded debris with different single-file systems: Reciproc, F360 and OneShape versus Mtwo.

Science.gov (United States)

Bürklein, S; Benten, S; Schäfer, E

2014-05-01

To assess in a laboratory setting the amount of apically extruded debris associated with different single-file nickel-titanium instrumentation systems compared to one multiple-file rotary system. Eighty human mandibular central incisors were randomly assigned to four groups (n = 20 teeth per group). The root canals were instrumented according to the manufacturers' instructions using the reciprocating single-file system Reciproc, the single-file rotary systems F360 and OneShape and the multiple-file rotary Mtwo instruments. The apically extruded debris was collected and dried in pre-weighed glass vials. The amount of debris was assessed with a micro balance and statistically analysed using anova and post hoc Student-Newman-Keuls test. The time required to prepare the canals with the different instruments was also recorded. Reciproc produced significantly more debris compared to all other systems (P file rotary systems and the multiple-file rotary system (P > 0.05). Instrumentation with the three single-file systems was significantly faster than with Mtwo (P systems caused apical debris extrusion. Rotary instrumentation was associated with less debris extrusion compared to reciprocal instrumentation. © 2013 International Endodontic Journal. Published by John Wiley & Sons Ltd.

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.

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.

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.

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.

Microtomography-based comparison of reciprocating single-file F2 ProTaper technique versus rotary full sequence.

Science.gov (United States)

Paqué, Frank; Zehnder, Matthias; De-Deus, Gustavo

2011-10-01

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. 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 using ProTaper, and group 2, reciprocate instrumentation with 1 single ProTaper F2 instrument. Specimens were scanned initially and after root canal preparation with an isotropic resolution of 20 μm by using a micro-computed tomography system. The following parameters were assessed: changes in dentin volume, percentage of shaped canal walls, and degree of canal transportation. In addition, the time required to reach working length with the F2 instrument was recorded. Preoperatively, there were no differences regarding root canal curvature and volume between experimental groups. Overall, instrumentation led to enlarged canal shapes with no evidence of preparation errors. There were no statistical differences between the 2 preparation techniques in the anatomical parameters assessed (P > .01), except for a significantly higher canal transportation caused by the reciprocating file in the coronal canal third. On the other hand, preparation was faster by using the single-file technique (P ProTaper technique and conventional ProTaper full-sequence rotary approach were similar. However, the single-file F2 ProTaper technique was markedly faster in reaching working length. Copyright © 2011 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

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.

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.

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.

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)

Cone-beam Computed Tomographic Assessment of Canal Centering Ability and Transportation after Preparation with Twisted File and Bio RaCe Instrumentation.

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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.

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

Mechanical and geometric features of endodontic instruments and its clinical effect

Directory of Open Access Journals (Sweden)

Hyeon-Cheol Kim

2011-01-01

Full Text Available Introduction The aim of this paper is to discuss the mechanical and geometric features of Nickel-titanium (NiTi rotary files and its clinical effects. NiTi rotary files have been introduced to the markets with their own geometries and claims that they have better ability for the root canal shaping than their competitors. The contents of this paper include the (possible interrelationship between the geometries of NiTi file (eg. tip, taper, helical angle, etc and clinical performance of the files as follows; - Fracture modes of NiTi rotary files - Non-cutting guiding tip and glide path - Taper and clinical effects - Cross-sectional area and clinical effects - Heat treatments and surface characteristics - Screw-in effect and preservation of root dentin integrity - Designs for reducing screw-in effect Conclusions Based on the reviewed contents, clinicians may have an advice to use various brands of NiTi rotary instruments regarding their advantages which would fit for clinical situation.

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.

Pneumatic Rotary Actuator Position Servo System Based on ADE-PD Control

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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.

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.

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.

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)

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.)

Computed tomography evaluation of rotary systems on the root canal transportation and centering ability

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André PAGLIOSA

2015-01-01

Full Text Available Abstract : The endodontic preparation of curved and narrow root canals is challenging, with a tendency for the prepared canal to deviate away from its natural axis. The aim of this study was to evaluate, by cone-beam computed tomography, the transportation and centering ability of curved mesiobuccal canals in maxillary molars after biomechanical preparation with different nickel-titanium (NiTi rotary systems. Forty teeth with angles of curvature ranging from 20° to 40° and radii between 5.0 mm and 10.0 mm were selected and assigned into four groups (n = 10, according to the biomechanical preparative system used: Hero 642 (HR, Liberator (LB, ProTaper (PT, and Twisted File (TF. The specimens were inserted into an acrylic device and scanned with computed tomography prior to, and following, instrumentation at 3, 6 and 9 mm from the root apex. The canal degree of transportation and centering ability were calculated and analyzed using one-way ANOVA and Tukey’s tests (α = 0.05. The results demonstrated no significant difference (p > 0.05 in shaping ability among the rotary systems. The mean canal transportation was: -0.049 ± 0.083 mm (HR; -0.004 ± 0.044 mm (LB; -0.003 ± 0.064 mm (PT; -0.021 ± 0.064 mm (TF. The mean canal centering ability was: -0.093 ± 0.147 mm (HR; -0.001 ± 0.100 mm (LB; -0.002 ± 0.134 mm (PT; -0.033 ± 0.133 mm (TF. Also, there was no significant difference among the root segments (p > 0.05. It was concluded that the Hero 642, Liberator, ProTaper, and Twisted File rotary systems could be safely used in curved canal instrumentation, resulting in satisfactory preservation of the original canal shape.

Computed tomography evaluation of rotary systems on the root canal transportation and centering ability

International Nuclear Information System (INIS)

Pagliosa, Andre; Raucci-Neto, Walter; Silva-Souza, Yara Teresinha Correa; Alfredo, Edson; Sousa-Neto, Manoel Damiao; Versiani, Marco Aurelio

2015-01-01

The endodontic preparation of curved and narrow root canals is challenging, with a tendency for the prepared canal to deviate away from its natural axis. The aim of this study was to evaluate, by cone-beam computed tomography, the transportation and centering ability of curved mesiobuccal canals in maxillary molars after biomechanical preparation with different nickel-titanium (NiTi) rotary systems. Forty teeth with angles of curvature ranging from 20° to 40° and radii between 5.0 mm and 10.0 mm were selected and assigned into four groups (n = 10), according to the biomechanical preparative system used: Hero 642 (HR), Liberator (LB), ProTaper (PT), and Twisted File (TF). The specimens were inserted into an acrylic device and scanned with computed tomography prior to, and following, instrumentation at 3, 6 and 9 mm from the root apex. The canal degree of transportation and centering ability were calculated and analyzed using one-way ANOVA and Tukey’s tests (α = 0.05). The results demonstrated no significant difference (p > 0.05) in shaping ability among the rotary systems. The mean canal transportation was: -0.049 ± 0.083 mm (HR); -0.004 ± 0.044 mm (LB); -0.003 ± 0.064 mm (PT); -0.021 ± 0.064 mm (TF). The mean canal centering ability was: -0.093 ± 0.147 mm (HR); -0.001 ± 0.100 mm (LB); -0.002 ± 0.134 mm (PT); -0.033 ± 0.133 mm (TF). Also, there was no significant difference among the root segments (p > 0.05). It was concluded that the Hero 642, Liberator, ProTaper, and Twisted File rotary systems could be safely used in curved canal instrumentation, resulting in satisfactory preservation of the original canal shape. (author)

Computed tomography evaluation of rotary systems on the root canal transportation and centering ability

Energy Technology Data Exchange (ETDEWEB)

Pagliosa, Andre; Raucci-Neto, Walter; Silva-Souza, Yara Teresinha Correa; Alfredo, Edson, E-mail: ysousa@unaerp.br [Universidade de Ribeirao Preto (UNAERP), SP (Brazil). Fac. de Odontologia; Sousa-Neto, Manoel Damiao; Versiani, Marco Aurelio [Universidade de Sao Paulo (USP), Ribeirao Preto, SP (Brazil). Fac. de Odoentologia

2015-03-01

The endodontic preparation of curved and narrow root canals is challenging, with a tendency for the prepared canal to deviate away from its natural axis. The aim of this study was to evaluate, by cone-beam computed tomography, the transportation and centering ability of curved mesiobuccal canals in maxillary molars after biomechanical preparation with different nickel-titanium (NiTi) rotary systems. Forty teeth with angles of curvature ranging from 20° to 40° and radii between 5.0 mm and 10.0 mm were selected and assigned into four groups (n = 10), according to the biomechanical preparative system used: Hero 642 (HR), Liberator (LB), ProTaper (PT), and Twisted File (TF). The specimens were inserted into an acrylic device and scanned with computed tomography prior to, and following, instrumentation at 3, 6 and 9 mm from the root apex. The canal degree of transportation and centering ability were calculated and analyzed using one-way ANOVA and Tukey’s tests (α = 0.05). The results demonstrated no significant difference (p > 0.05) in shaping ability among the rotary systems. The mean canal transportation was: -0.049 ± 0.083 mm (HR); -0.004 ± 0.044 mm (LB); -0.003 ± 0.064 mm (PT); -0.021 ± 0.064 mm (TF). The mean canal centering ability was: -0.093 ± 0.147 mm (HR); -0.001 ± 0.100 mm (LB); -0.002 ± 0.134 mm (PT); -0.033 ± 0.133 mm (TF). Also, there was no significant difference among the root segments (p > 0.05). It was concluded that the Hero 642, Liberator, ProTaper, and Twisted File rotary systems could be safely used in curved canal instrumentation, resulting in satisfactory preservation of the original canal shape. (author)

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...

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.

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

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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.

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.

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.

Performance characterization of Watson Ahumada motion detector using random dot rotary motion stimuli.

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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.

Cyclic fatigue resistance of ProTaper Universal instruments when subjected to static and dynamic tests.

Science.gov (United States)

Lopes, Hélio P; Britto, Izabelle M O; Elias, Carlos N; Machado de Oliveira, Julio C; Neves, Mônica A S; Moreira, Edson J L; Siqueira, José F

2010-09-01

This study evaluated the number of cycles to fracture of ProTaper Universal S2 instruments when subjected to static and dynamic cyclic fatigue tests. ProTaper Universal S2 instruments were used until fracture in an artificial curved canal under rotational speed of 300 rpm in either a static or a dynamic test model. Afterward, the length of the fractured segments was measured and fractured surfaces and helical shafts analyzed by scanning electron microscopy (SEM). The number of cycles to fracture was significantly increased when instruments were tested in the dynamic model (Pductile mode. Plastic deformation was not observed in the helical shaft of fractured instruments. The number of cycles to fracture ProTaper Universal S2 instruments significantly increased with the use of instruments in a dynamic cyclic fatigue test compared with a static model. These findings reinforce the need for performing continuous pecking motions during rotary instrumentation of curved root canals. Copyright (c) 2010 Mosby, Inc. All rights reserved.

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.

Cell Attachment Following Instrumentation with Titanium and Plastic Instruments, Diode Laser, and Titanium Brush on Titanium, Titanium-Zirconium, and Zirconia Surfaces.

Science.gov (United States)

Lang, Melissa S; Cerutis, D Roselyn; Miyamoto, Takanari; Nunn, Martha E

2016-01-01

The aim of this study was to evaluate the surface characteristics and gingival fibroblast adhesion of disks composed of implant and abutment materials following brief and repeated instrumentation with instruments commonly used in procedures for implant maintenance, stage-two implant surgery, and periimplantitis treatment. One hundred twenty disks (40 titanium, 40 titaniumzirconium, 40 zirconia) were grouped into treatment categories of instrumentation by plastic curette, titanium curette, diode microlaser, rotary titanium brush, and no treatment. Twenty strokes were applied to half of the disks in the plastic and titanium curette treatment categories, while half of the disks received 100 strokes each to simulate implant maintenance occurring on a repetitive basis. Following analysis of the disks by optical laser profilometry, disks were cultured with human gingival fibroblasts. Cell counts were conducted from scanning electron microscopy (SEM) images. Differences in surface roughness across all instruments tested for zirconia disks were negligible, while both titanium disks and titaniumzirconium disks showed large differences in surface roughness across the spectrum of instruments tested. The rotary titanium brush and the titanium curette yielded the greatest overall mean surface roughness, while the plastic curette yielded the lowest mean surface roughness. The greatest mean cell counts for each disk type were as follows: titanium disks with plastic curettes, titanium-zirconium disks with titanium curettes, and zirconia disks with the diode microlaser. Repeated instrumentation did not result in cumulative changes in surface roughness of implant materials made of titanium, titanium-zirconium, or zirconia. Instrumentation with plastic implant curettes on titanium and zirconia surfaces appeared to be more favorable than titanium implant curettes in terms of gingival fibroblast attachment on these surfaces.

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.

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.

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. .

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

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.

Multi-functional hinge equipped with a magneto-rheological rotary damper for solar array deployment system

Science.gov (United States)

Wen, Mingfu; Yu, Miao; Fu, Jie; Wu, Zhengzhong

2015-02-01

This article describes the design and simulation of a novel multi-functional hinge equipped with a rotary magnetorheological damper for solar array deployment system, which is comprised of a hinge, an angular sensor, a positioning and locking mechanism and a rotary damper. In order to achieve the compact design in structure, some components were reused in different function modules. It's the first to use magnet-rheological fluid (MRF) to dissipate the energy in solar array deployment system. The main advantage in using MR rotary damper instead of a viscous fluid rotary damper is that the damping force of MR damper can be adjusted according to the external magnetic field environment excited. A mechanic model was built and the structure design was focused on the MR rotary damper, a damping force model of this damper is deduced based on hydromechanics with Bingham plastic constitutive model. A simulation of deployment motion was taken to validate the motion sequence of various components during the unfolding and locking process. It can be obtained that a constant damping coefficient can hardly balance the different performance of solar deployment system, then a simulation of the proposed deployment system equipped with rotary MR damper was carried out. According to the simulation, it can be obtained that the terminal velocity decreased by 75.81% and the deployment time decreased by 72.37% compared with a given constant damping coefficients. Therefore, the proposed new type of rotary damper can reach a compromise with different performance utilizing an on-off control strategy.

Note: A novel rotary actuator driven by only one piezoelectric actuator.

Science.gov (United States)

Huang, Hu; Fu, Lu; Zhao, Hongwei; Shi, Chengli; Ren, Luquan; Li, Jianping; Qu, Han

2013-09-01

This paper presents a novel piezo-driven rotary actuator based on the parasitic motion principle. Output performances of the rotary actuator were tested and discussed. Experiment results indicate that using only one piezoelectric actuator and simple sawtooth wave control, the rotary actuator reaches the rotation velocity of about 20,097 μrad/s when the driving voltage is 100 V and the driving frequency is 90 Hz. The actuator can rotate stably with the minimum resolution of 0.7 μrad. This paper verifies feasibility of the parasitic motion principle for applications of rotary actuators, providing new design ideas for precision piezoelectric rotary actuators.

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.

Rotary compression process for producing toothed hollow shafts

Directory of Open Access Journals (Sweden)

J. Tomczak

2014-10-01

Full Text Available The paper presents the results of numerical analyses of the rotary compression process for hollow stepped shafts with herringbone teeth. The numerical simulations were performed by Finite Element Method (FEM, using commercial software package DEFORM-3D. The results of numerical modelling aimed at determining the effect of billet wall thickness on product shape and the rotary compression process are presented. The distributions of strains, temperatures, damage criterion and force parameters of the process determined in the simulations are given, too. The numerical results obtained confirm the possibility of producing hollow toothed shafts from tube billet by rotary compression methods.

Control and data acquisition system for rotary compressor

Directory of Open Access Journals (Sweden)

Buczaj Marcin

2017-01-01

Full Text Available The rotary compressor (crimping machine is a machine designed for making hollow forgings. The rotary compressor is a prototype device designed and built at the Technical University of Lublin. The compressor is dedicated to perform laboratory tests related to the hollow forgings of various shapes using different materials. Since the rotary compressor is an experimental device, there is no control and acquisition data system available. The article presents the concept and the capabilities of the computer control and data acquisition system supporting rotary compressing process. The main task of software system is acquisition of force and kinetic parameters related to the analysed process of the rotary forging compression. The software allows the user to declare the course of the forming forgings. This system allows current recording and analysis of four physical values: feed rate (speed of working head movement, hydraulic oil pressure at inlet and outlet of hydraulic cylinder and the torque of engine. Application functions can be divided into three groups: the configuration of the pressing process, the acquisition and analysis of data from the pressing process and the recording and presentation of stored results. The article contains a detailed description about hardware and software implementation of mentioned functions.

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.

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.

Miniaturized Rotary Actuators Using Shape Memory Alloy for Insect-Type MEMS Microrobot

Directory of Open Access Journals (Sweden)

Ken Saito

2016-03-01

Full Text Available Although several types of locomotive microrobots have been developed, most of them have difficulty locomoting on uneven surfaces. Thus, we have been focused on microrobots that can locomote using step patterns. We are studying insect-type microrobot systems. The locomotion of the microrobot is generated by rotational movements of the shape memory alloy-type rotary actuator. In addition, we have constructed artificial neural networks by using analog integrated circuit (IC technology. The artificial neural networks can output the driving waveform without using software programs. The shape memory alloy-type rotary actuator and the artificial neural networks are constructed with silicon wafers; they can be integrated by using micro-electromechanical system (MEMS technology. As a result, the MEMS microrobot system can locomote using step patterns. The insect-type MEMS microrobot system is 0.079 g in weight and less than 5.0 mm in size, and its locomotion speed is 2 mm/min. The locomotion speed is slow because the heat of the shape memory alloy conducts to the mechanical parts of the MEMS microrobot. In this paper, we discuss a new rotary actuator compared with the previous model and show the continuous rotation of the proposed rotary actuator.

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.)

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...

Grating exchange system of independent mirror supported by floating rotary stage

Science.gov (United States)

Zhang, Jianhuan; Tao, Jin; Liu, Yan; Nan, Yan

2015-10-01

The performance of The Grating Exchange System can satisfy the Thirty Meter Telescope - TMT for astronomical observation WFOS index requirements and satisfy the requirement of accuracy in the grating exchange. It is used to install in the MOBIE and a key device of MOBIE. The Wide Field Optical Spectrograph (WFOS) is one of the three first-light observing capabilities selected by the TMT Science Advisory Committee. The Multi-Object Broadband Imaging Echellette (MOBIE) instrument design concept has been developed to address the WFOS requirements as described in the TMT Science-Based Requirements Document (SRD). The Grating Exchange System uses a new type of separate movement way of three grating devices and a mirror device. Three grating devices with a mirror are able to achieve independence movement. This kind of grating exchange system can effectively solve the problem that the volume of the grating change system is too large and that the installed space of MOBIE instruments is too limit. This system adopts the good stability, high precision of rotary stage - a kind of using air bearing (Air bearing is famous for its ultra-high precision, and can meet the optical accuracy requirement) and rotation positioning feedback gauge turntable to support grating device. And with a kind of device which can carry greater weight bracket fixed on the MOBIE instrument, with two sets of servo motor control rotary stage and the mirror device respectively. And we use the control program to realize the need of exercising of the grating device and the mirror device. Using the stress strain analysis software--SolidWorks for stress and strain analysis of this structure. And then checking the structure of the rationality and feasibility. And prove that this system can realize the positioning precision under different working conditions can meet the requirements of imaging optical grating diffraction efficiency and error by the calculation and optical performance analysis.

Seismic qualification of the rotary relay for use in the Trojan and Diablo Canyon Auxiliary Safeguards Cabinets

International Nuclear Information System (INIS)

Riggio, M.D.; Jarecki, S.J.

1977-10-01

This report presents the results of the analysis performed for the seismic qualification of the rotary relay for use in the Trojan and Diablo Canyon Auxiliary Safeguards Cabinets. A finite element model of the cabinet was developed from seismic test results. This model was analytically subjected to a simulated 3D floor acceleration time history that enveloped, simultaneously, the Trojan and the June 1969 Diablo Canyon Safe Shutdown Earthquake requirements. The dynamic response of the cabinet at the mounting location of the rotary relays was determined. The calculated acceleration time histories were converted to response spectra and these response spectra were compared to the test response spectra successfully achieved during the rotary relay seismic qualification tests. It was found that the dynamic motion levels at the rotary relays, when mounted in the Trojan or Diablo Canyon Auxiliary Safeguards Cabinets, do not exceed the levels for which they were previously seismically qualified by tests. Consequently, the rotary relays are seismically qualified for use in the Trojan or Diablo Canyon Auxiliary Safeguards Cabinets

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.

A cost-minimization analysis of root canal treatment before and after education in nickel-titanium rotary technique in general practice.

Science.gov (United States)

Koch, M; Tegelberg, A; Eckerlund, I; Axelsson, S

2012-07-01

To compare root canal treatments performed before and after education in a nickel-titanium rotary technique (NiTiR) with respect to costs for instrumentation and number of instrumentation sessions in a County Public Dental Service in Sweden.   Following education, 77% of the general dental practitioners adopted completely the NiTiR. The randomly selected sample comprised 850 root canal treatments: 425 performed after the education, mainly using the NiTiR-technique (group A) and 425 performed before, using mainly stainless steel hand instrumentation (SSI) (group B). The number of instrumentation sessions in root canal treatments in group A and B was calculated. A CMA was undertaken on the assumption that treatment outcome was identical in group A and B. Direct costs associated with SSI and NiTiR were estimated and compared. Investment costs required for implementation of NiTiR were calculated, but not included in the CMA. Instrumentation sessions were counted in 418 (98%) root canal treatments performed in group A and 419 (99%) in group B. The number of instrumentation sessions in group A was significantly lower; 2.38, compared with 2.82 in group B (P session was saved. Root canal treatments in teeth with one canal, and three or more canals, were completed in significantly fewer instrumentation sessions after the education (P sessions were SEK 2587 (USD 411) for group A and SEK 2851 (USD 453) for group B, for teeth with one canal, and SEK 2946 (USD 468) for group A and SEK 3510 (USD 558) for group B, for teeth with three or more canals (year 2011). Root canal treatments of teeth with two canals showed no significant difference with respect to number of instrumentation sessions and costs. Significantly fewer instrumentation sessions were required in group A, and root canal instrumentation therefore costs less than in group B. On the assumption that treatment outcome is identical in group A and B, root canal instrumentation performed after the education was more

Effect of the sterilization on the cutting efficiency of ProTaper® and K3® endodontic instruments

Directory of Open Access Journals (Sweden)

Alex Niederauer Becker

2009-12-01

Full Text Available Objective: This objective of this study was to evaluate the effect of sterilization on the cutting efficiency of rotary endodontic instruments, ProTaper® (Dentsply Maillefer Instruments S.A., Ballaigues, Suíça and K3® (Sybron/Kerr, Orange, CA, USA, by the time X weighing method. Method: For this purpose, 60 simulated canals and 66 instruments were used (36 of the ProTaper® system, (Dentsply Maillefer Instruments S.A., Ballaigues, Switzerland and 30 of the K3® system (Sybron/Kerr, Orange, CA, USA. The rotary instruments were divided into four experimental groups. The instruments in Group A (K3®, Sybron/Kerr, Orange, CA, USA and Group B (ProTaper®, Dentsply Maillefer Instruments S.A., Ballaigues, Switzerland, were subjected to a process of cleaning and sterilization. Whereas the instruments in Group C (K3®, Sybron/Kerr, Orange, CA, USA and Group D (ProTaper®, Dentsply Maillefer Instruments S.A., Ballaigues, Switzerland, were subjected to the cleanness process only, and were not sterilized. Results: As regards analysis of the results, the Student’s-t test was used, by which it was verified that the instruments in Group had greater cutting efficiency in comparison with those in Group B. Similarly the instruments in Group C had greater cutting efficiency in comparison with those in Group D, nevertheless, there was no statistically significant difference. Moreover, as regards the number times of use, there was also no statistically significant difference between the experimental groups. However in all the groups there was a decrease in the cutting efficiency with an increasing number of times of use. Conclusion: Thus, the cutting efficiency of rotary endodontic instruments K3® (Sybron/Kerr, Orange, CA, USA and ProTaper® (Dentsply Maillefer Instruments S.A., Ballaigues, Suição was not statistically affected after the use of 6 autoclave sterilization cycles.

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

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

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.

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.

Research on dynamic balancing simulation of rotary shaft based on ADAMS

Science.gov (United States)

Zheng, Weiqiang; Rui, Chengjie; Yang, Jie; Liu, Pingyi

2018-02-01

Due to the design and processing technology of rotary shaft, the mass center of it does not coincide with the rotating axis of the rotary shaft and there is an unbalanced mass. The unbalanced mass can have some disadvantages, such as the centrifugal force, the vibration and so on. Those disadvantages could reduce the accuracy and service life of the equipment.In this paper, the dynamic balance of the rotary shaft is analysed by the theory analysis combined with the dynamic simulation software. This method ensures that the rotary shaft meets the dynamic balancing requirements during the design stage. It effectively supports the structural design of the rotary shift, and provides a way of thinking and method for the design and development of the same type of products.

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.

Efficacy of CM-Wire, M-Wire, and Nickel-Titanium Instruments for Removing Filling Material from Curved Root Canals: A Micro-Computed Tomography Study.

Science.gov (United States)

Rodrigues, Clarissa Teles; Duarte, Marco Antonio Hungaro; de Almeida, Marcela Milanezi; de Andrade, Flaviana Bombarda; Bernardineli, Norberti

2016-11-01

The aim of this ex vivo study was to evaluate the removal of filling material after using CM-wire, M-wire, and nickel-titanium instruments in both reciprocating and rotary motions in curved canals. Thirty maxillary lateral incisors were divided into 9 groups according to retreatment procedures: Reciproc R25 followed by Mtwo 40/.04 and ProDesign Logic 50/.01 files; ProDesign R 25/.06 followed by ProDesign Logic 40/.05 and ProDesign Logic 50/.01 files; and Gates-Glidden drills, Hedström files, and K-files up to apical size 30 followed by K-file 40 and K-file 50 up to the working length. Micro-computed tomography scans were performed before and after each reinstrumentation procedure to evaluate root canal filling removal. Statistical analysis was performed with Kruskal-Wallis, Friedman, and Wilcoxon tests (P < .05). No significant differences in filling material removal were found in the 3 groups of teeth. The use of Mtwo and ProDesign Logic 40/.05 rotary files did not enhance filling material removal after the use of reciprocating files. The use of ProDesign Logic 50/.01 files significantly reduced the amount of filling material at the apical levels compared with the use of reciprocating files. Association of reciprocating and rotary files was capable of removing a large amount of filling material in the retreatment of curved canals, irrespective of the type of alloy of the instruments. The use of a ProDesign Logic 50/.01 file for apical preparation significantly reduced the amount of remnant material in the apical portion when compared with reciprocating instruments. Copyright © 2016 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

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.

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

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.

Apical instrumentation in endodontic therapy

Directory of Open Access Journals (Sweden)

Kurniasri Darliana

2007-07-01

Full Text Available Cleaning and shaping of the root canal as the foundation for successful endodontic therapy. Cleaning of the root canal as the removal of all the contents of the root canal systems before and during shaping. Mechanical cleaning as the most important part of the root canal therapy. Instrumentation of the apical region has long been considered to be an essential component in the cleaning and shaping process. The apical area as the critical zone for instrumentation. The apical portion of the root canal system can retain microorganisms that could potentially cause periradicular inflammation. The nickel-titanium rotary instrumentation system to facilitate the cleaning and shaping process. Larger instrumentation sizes not only allow proper irrigation but also significantly decrease remaining bacteria in the canal system. How the larger apical sizes preparation must be achieved to clinical success. This paper will describe the major factors impacting the selection of final apical size, the factors are the anatomy of the apical constriction, root canal diameter, apical instrumentation, and bacteria in dentin tubuli.

Effectiveness of ProTaper, D-RaCe, and Mtwo retreatment files with and without supplementary instruments in the removal of root canal filling material.

Science.gov (United States)

Marques da Silva, B; Baratto-Filho, F; Leonardi, D P; Henrique Borges, A; Volpato, L; Branco Barletta, F

2012-10-01

To assess the efficacy of different retreatment rotary files in removing gutta-percha and endodontic sealer from canals. Ninety straight single-rooted premolars were prepared up to a size 30 and filled with gutta-percha and sealer and then randomly assigned to six retreatment groups (n = 15). Groups I, III, and V were retreated using rotary systems ProTaper Universal Retreatment (PTUR), D-RaCe, and Mtwo Retreatment, respectively. Groups II, IV, and VI were retreated using the additional instruments F4, size 40, .04 taper RaCe, and size 40, .04 taper Mtwo, respectively. The roots were split vertically, and images of the halves were obtained using a high-resolution scanner and evaluated with AutoCAD software to calculate the percentage of residual material. Data were analyzed with Kruskal-Wallis and Student-Newman-Keuls tests using a 5% significance cutoff (P 0.05) between groups when additional instruments were used. The percentage of residual material was lowest in the PTUR group and was statistically significant only when compared to the D-RaCe system (P = 0.0038). All root canals had residual filling material after retreatment even when additional instruments were used. © 2012 International Endodontic Journal.

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.

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.

A Review of Heavy-Fueled Rotary Engine Combustion Technologies

Science.gov (United States)

2011-05-01

Triangle Park, NC, 2009. 17. Shimizu, R.; Tadokoro, T.; Nakanishi, T.; Funamoto, J. Mazda 4-Rotor Rotary Engine for the Le Mans 24-Hour Endurance...2000. 102. Schock, H.; Hamady, F.; Somerton , C. Stratified Charge Rotary Engine Combustion Studies; NASA-CR-197985; National Aeronautics and

Shaping ability of two M-wire and two traditional nickel-titanium instrumentation systems in S-shaped resin canals.

Science.gov (United States)

Ceyhanli, K T; Kamaci, A; Taner, M; Erdilek, N; Celik, D

2015-01-01

The aim of this study was to evaluate the shaping effects of two M-wire and two traditional nickel-titanium (NiTi) rotary systems in simulated S-shaped resin canals. Forty simulated S-shaped canals in resin blocks were instrumented with two traditional (ProTaper, Sendoline S5) and two M-wire (WaveOne, GT series X) NiTi systems according to the manufacturers' instructions. Ten resin blocks were used for each system. Pre- and post-instrumentation images were captured using a stereomicroscope and superimposed with an image program. Canal transportation, material removal, and aberrations were evaluated and recorded as numeric parameters. Data were analyzed using one-way ANOVA and post-hoc Tukey tests with a 95% confidence interval. There were significant differences between systems in terms of transportation and material removal (Pwire or traditional NiTi) and kinematics (rotary or reciprocating motion) did not affect the shaping abilities of the systems. The extended file designs of highly tapered NiTi systems (ProTaper, WaveOne) resulted in greater deviations from the original root canal trace and more material removal when compared to less tapered systems (Sendoline S5, GT series X).

Comparison of the shaping ability of Twisted Files with ProTaper and RevoS nickel-titanium instruments in simulated canals

Directory of Open Access Journals (Sweden)

Cumhur Aydin

2012-09-01

Conclusion: According to the results of this study, TFs respected the original canal curvature better than did ProTaper and RevoS rotary NiTi instruments. TF instruments also provided a more-centered apical preparation of the simulated canals at the apical third.

A survey of experience-based preference of Nickel-Titanium rotary files and incidence of fracture among general dentists

Directory of Open Access Journals (Sweden)

WooCheol Lee

2012-11-01

Full Text Available Objectives The purpose was to investigate the preference and usage technique of NiTi rotary instruments and to retrieve data on the frequency of re-use and the estimated incidence of file separation in the clinical practice among general dentists. Materials and Methods A survey was disseminated via e-mail and on-site to 673 general dentists. The correlation between the operator's experience or preferred technique and frequency of re-use or incidence of file fracture was assessed. Results A total of 348 dentists (51.7% responded. The most frequently used NiTi instruments was ProFile (39.8% followed by ProTaper. The most preferred preparation technique was crown-down (44.6%. 54.3% of the respondents re-used NiTi files more than 10 times. There was a significant correlation between experience with NiTi files and the number of reuses (p = 0.0025. 54.6% of the respondents estimated experiencing file separation less than 5 times per year. The frequency of separation was significantly correlated with the instrumentation technique (p = 0.0003. Conclusions A large number of general dentists in Korea prefer to re-use NiTi rotary files. As their experience with NiTi files increased, the number of re-uses increased, while the frequency of breakage decreased. Operators who adopt the hybrid technique showed less tendency of separation even with the increased number of re-use.

Cleaning capacity promoted by motor-driven or manual instrumentation using ProTaper Universal system: Histological analysis

OpenAIRE

da Frota, Matheus Franco; Filho, Idomeo Bonetti; Berbert, F?bio Luiz Camargo Villela; Sponchiado, Emilio Carlos; Marques, Andr? Augusto Franco; Garcia, Lucas da Fonseca Roberti

2013-01-01

Aim: The aim of this study was to assess the cleaning capacity of the Protaper system using motor-driven or manual instrumentation. Materials and Methods: Ten mandibular molars were randomly separated into 2 groups (n = 5) according to the type of instrumentation performed, as follows: Group 1 - instrumentation with rotary nickel-titanium (Ni-Ti) files using ProTaper Universal System (Dentsply/Maillefer); and, Group 2 - instrumentation with Ni-Ti hand files using ProTaper Universal (Den...

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

Streaming current of a rotary atomizer for energy harvesting

NARCIS (Netherlands)

Nguyen, Trieu; de Boer, Hans L.; Tran, T.; van den Berg, Albert; Eijkel, Jan C.T.; Zengerle, R.

2013-01-01

We present the experimental results of an energy conversion system based on a rotary atomizer and the streaming current phenomenon. The advantage of using a rotary atomizer instead of a channel or membrane micropore as in conventional pressure-driven approached is that the centrifugal force exerted

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.

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.

Assessment of a lubricant based nanofluid application in a rotary system

International Nuclear Information System (INIS)

Hajmohammadi, M.R.

2017-01-01

Highlights: • Application of metallic nanoparticles in a rotary system is evaluated. • Evaluations are based on first and second laws of thermodynamics. • Two-phase numerical method is used and lubricant is considered inhomogeneous. • Nanoparticles with limited concentricity in lowspeed rotary system are recommended. - Abstract: Rotary systems and nanofluids are frequently used in energy conversion and management systems. In this paper, a numerical study is performed to evaluate the application of metallic nano-particles in a rotary system filled with a lubricant from first and second laws of thermodynamics points of view. The nano-lubricant (lubricant based nanofluid) is considered inhomogeneous with dependent transport properties on nano-particles volume fraction, nano-particles size and the temperature. A two-phase model is undertaken to account for the Brownian motion and thermophoresis diffusion. The principal objective centers in the advantages and penalties of using nano-lubricant over the pure lubricant on the basis of first and second law (of thermodynamics). The numerical results demonstrate that the nano-particles enhance the thermal performance of the rotary system. However, undesirable aspect from hydro-dynamical and second law (of thermodynamic) perspectives are reported. While a nano-lubricant with limited volume fraction in low speed rotary system is recommended, the disadvantages of nano-lubricants with high volume fractions and/or used in a high-speed rotary system are dominant to nano-lubricants advantages and must be avoided.

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.

Computational experience with a three-dimensional rotary engine combustion model

Science.gov (United States)

Raju, M. S.; Willis, E. A.

1990-04-01

A new computer code was developed to analyze the chemically reactive flow and spray combustion processes occurring inside a stratified-charge rotary engine. Mathematical and numerical details of the new code were recently described by the present authors. The results are presented of limited, initial computational trials as a first step in a long-term assessment/validation process. The engine configuration studied was chosen to approximate existing rotary engine flow visualization and hot firing test rigs. Typical results include: (1) pressure and temperature histories, (2) torque generated by the nonuniform pressure distribution within the chamber, (3) energy release rates, and (4) various flow-related phenomena. These are discussed and compared with other predictions reported in the literature. The adequacy or need for improvement in the spray/combustion models and the need for incorporating an appropriate turbulence model are also discussed.

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.

Comparative Analysis of Canal Centering Ability of Different Single File Systems Using Cone Beam Computed Tomography- An In-Vitro Study.

Science.gov (United States)

Agarwal, Rolly S; Agarwal, Jatin; Jain, Pradeep; Chandra, Anil

2015-05-01

The ability of an endodontic instrument to remain centered in the root canal system is one of the most important characteristic influencing the clinical performance of a particular file system. Thus, it is important to assess the canal centering ability of newly introduced single file systems before they can be considered a viable replacement of full-sequence rotary file systems. The aim of the study was to compare the canal transportation, centering ability, and time taken for preparation of curved root canals after instrumentation with single file systems One Shape and Wave One, using cone-beam computed tomography (CBCT). Sixty mesiobuccal canals of mandibular molars with an angle of curvature ranging from 20(o) to 35(o) were divided into three groups of 20 samples each: ProTaper PT (group I) - full-sequence rotary control group, OneShape OS (group II)- single file continuous rotation, WaveOne WO - single file reciprocal motion (group III). Pre instrumentation and post instrumentation three-dimensional CBCT images were obtained from root cross-sections at 3mm, 6mm and 9mm from the apex. Scanned images were then accessed to determine canal transportation and centering ability. The data collected were evaluated using one-way analysis of variance (ANOVA) with Tukey's honestly significant difference test. It was observed that there were no differences in the magnitude of transportation between the rotary instruments (p >0.05) at both 3mm as well as 6mm from the apex. At 9 mm from the apex, Group I PT showed significantly higher mean canal transportation and lower centering ability (0.19±0.08 and 0.39±0.16), as compared to Group II OS (0.12±0.07 and 0.54±0.24) and Group III WO (0.13±0.06 and 0.55±0.18) while the differences between OS and WO were not statistically significant. It was concluded that there was minor difference between the tested groups. Single file systems demonstrated average canal transportation and centering ability comparable to full sequence

Comparative Analysis of Canal Centering Ability of Different Single File Systems Using Cone Beam Computed Tomography- An In-Vitro Study

Science.gov (United States)

Agarwal, Jatin; Jain, Pradeep; Chandra, Anil

2015-01-01

Background The ability of an endodontic instrument to remain centered in the root canal system is one of the most important characteristic influencing the clinical performance of a particular file system. Thus, it is important to assess the canal centering ability of newly introduced single file systems before they can be considered a viable replacement of full-sequence rotary file systems. Aim The aim of the study was to compare the canal transportation, centering ability, and time taken for preparation of curved root canals after instrumentation with single file systems One Shape and Wave One, using cone-beam computed tomography (CBCT). Materials and Methods Sixty mesiobuccal canals of mandibular molars with an angle of curvature ranging from 20o to 35o were divided into three groups of 20 samples each: ProTaper PT (group I) – full-sequence rotary control group, OneShape OS (group II)- single file continuous rotation, WaveOne WO – single file reciprocal motion (group III). Pre instrumentation and post instrumentation three-dimensional CBCT images were obtained from root cross-sections at 3mm, 6mm and 9mm from the apex. Scanned images were then accessed to determine canal transportation and centering ability. The data collected were evaluated using one-way analysis of variance (ANOVA) with Tukey’s honestly significant difference test. Results It was observed that there were no differences in the magnitude of transportation between the rotary instruments (p >0.05) at both 3mm as well as 6mm from the apex. At 9 mm from the apex, Group I PT showed significantly higher mean canal transportation and lower centering ability (0.19±0.08 and 0.39±0.16), as compared to Group II OS (0.12±0.07 and 0.54±0.24) and Group III WO (0.13±0.06 and 0.55±0.18) while the differences between OS and WO were not statistically significant Conclusion It was concluded that there was minor difference between the tested groups. Single file systems demonstrated average canal

A rotary pneumatic actuator for the actuation of the exoskeleton knee joint

Directory of Open Access Journals (Sweden)

Jobin Varghese

2017-07-01

Full Text Available Rotary pneumatic actuators that are made out of linear one are always best suited for exoskeleton joint actuation due to its inherent power to weight ratio. This work is a modified version of knee actuation system that has already been developed and major modifications are made in order to make it more suitable for human wearing and also to reduce its bulkiness and complexity. The considered actuator system is a rotary actuator where a pulley converts the linear motion of the standard pneumatic piston into the rotary motion. To prove the capability of the actuator, its performance characteristics such as torque and power produced are compared to the required torque and power at the knee joint of the exoskeleton in swing phase and are found to be excellent. The two-way analysis of variance (ANOVA is performed to find the effect of the throat area valve on knee angle. The ANOVA shows the significant effect of the throat area variation on the knee angle flexion made by the proposed actuator. A relationship between the throat area of flow control valve, that is connected to the exit port of the direction control valve, and angular displacement of the knee joint has been formulated. This relationship can be used to design a control system to regulate the mass flow rate of air at the exit and hence the angular velocity of the knee joint can be controlled. Keywords: Driven pulley, Flow control valve, Rotary, Pneumatic cylinder

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

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

[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.

EVALUATION OF ALTERNATIVE FILTER MEDIA FOR THE ROTARY MICROFILTER

Energy Technology Data Exchange (ETDEWEB)

Poirier, M.; Herman, D.; Bhave, R.

2011-09-13

SRS is currently developing and testing several processes to treat high level radioactive liquid waste. These processes include the Integrated Salt Disposition Process (ISDP), the Salt Waste Processing Facility (SWPF), and the Small Column Ion Exchange Process (SCIX). Each of these processes has a solid-liquid separation process that limits its throughput. SRNL researchers identified and tested the rotary microfilter as a technology to increase solid-liquid separation throughput. The testing showed significant improvement in filter flux with the rotary microfilter over the baseline crossflow filter (i.e., 2.5-6.5X during scoping tests, as much as 10X in actual waste tests, and approximately 3X in pilot-scale tests). SRNL received funding from DOE EM-21, and subsequently DOE EM-31 to develop the rotary microfilter for high level radioactive service. The work has included upgrading the rotary microfilter for radioactive service, testing with simulated SRS waste streams, and testing it with simulated Hanford waste streams. While the filtration rate is better than that obtained during testing of crossflow filters, the authors believe the rotary microfilter throughput can be improved by using a better filter membrane. The rotary microfilter membrane is made of stainless steel (Pall PMM050). Previous testing, funded by DOE EM-21, showed that asymmetric filters composed of a ceramic membrane on top of a stainless steel support produced higher filter flux than 100% stainless steel symmetric filters in crossflow filter tests. In that testing, the Pall Accusep and Graver filters produced 13-21% larger filter flux than the baseline 0.1 {micro}m Mott filter. While the improvement in flux is not as dramatic as the improvement of the rotary filter over a crossflow filter, a 13-21% increase could reduce the lifetime of a 30 year process by 4-6 years, with significant cost savings. Subsequent rotary filter testing showed the Pall PMM050 stainless steel filter membrane produced

A rotary multimodal hybrid energy harvesting device powered by human motion

Science.gov (United States)

Larkin, Miles R.

This thesis presents a novel hybrid multimodal energy harvesting device consisting of an unbalanced rotary disk that supports two transduction methods, piezoelectric and electromagnetic. The device generates electrical energy from oscillatory motion either orthogonal or parallel to the rotary axis to power electronic devices. Analytical models of the device were developed, from which numerical simulations were performed for several different generator sizes. Two prototypes, 180 mm and 100 mm in diameter, respectively, were fabricated and characterized experimentally with a modal shaker. The 180 mm prototype generated 120 mW from the electromagnetic system at 5 Hz and 0.8g, and 4.23 mW from the piezoelectric system at 20.2 Hz and 0.4g excitation acceleration. Finally, the power generation capabilities of the two prototypes were compared to other similar devices.

An in vitro study to determine fracture resistance of tooth roots after different instrumentation techniques

Directory of Open Access Journals (Sweden)

Marri Shilpa Reddy

2016-01-01

Conclusion: Preparation of canals with a conventional hand instrumentation technique using 0.02 taper K-files showed highest fracture resistance with least amount of dentin removed at all levels followed by Endowave, ProTaper Hand, and Rotary files.

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.

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

Controlled-air and rotary-kiln proof-of-principle tests

International Nuclear Information System (INIS)

Hedahl, T.G.

1982-05-01

Although the incinerator tests did not represent optimized processing, general system design characteristics were established. The test results indicated that the rotary kiln incinerator would be most applicable in the Transuranic Waste Treatment Facility (TWTF) for the following reasons: (1) The rotary kiln is more capable of achieving near-complete combustion of the combustibles in the waste mixed with a high proportion of metal and noncombustible waste. Complete combustion of the combustible waste is preferred in order to reduce waste volume and ensure the production of a stable, immobilized waste form. (2) The rotary kiln processing appears to be more flexible. Kiln rotation rate, kiln incline, and waste feed rate and method are system variables which can be altered to meet the needs of processing variable waste compositions. The advantages of the rotary kiln system allow for a practical concept for processing a majority of the radioactive waste at the INEL. However, further engineering tests must be performed to determine the necessary processing angles and design information for TWTF waste processing

A review of Curtiss-Wright rotary engine developments with respect to general aviation potential

Science.gov (United States)

Jones, C.

1979-01-01

Aviation related rotary (Wankel-type) engine tests, possible growth directions and relevant developments at Curtiss-Wright have been reviewed. Automotive rotary engines including stratified charge are described and flight test results of rotary aircraft engines are presented. The current 300 HP engine prototype shows basic durability and competitive performance potential. Recent parallel developments have separately confirmed the geometric advantages of the rotary engine for direct injected unthrottled stratified charge. Specific fuel consumption equal to or better than pre- or swirl-chamber diesels, low emission and multi-fuel capability have been shown by rig tests of similar rotary engine.

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.

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%

Lift Production on Flapping and Rotary Wings at Low Reynolds Numbers

Science.gov (United States)

2016-02-26

AFRL-AFOSR-VA-TR-2016-0098 Flapping and Rotary Wing Lift at Low Reynolds Number Anya Jones MARYLAND UNIV COLLEGE PARK Final Report 02/26/2016...Lift Production on Flapping and Rotary Wings at Low Reynolds Numbers (YIP) 5a. CONTRACT NUMBER 5b. GRANT NUMBER FA9550-12-1-0251 5c. PROGRAM...necessary if the abstract is to be limited. Standard Form 298 Back (Rev. 8/98) Lift Production on Flapping and Rotary Wings at Low Reynolds Numbers

Leaching from waste incineration bottom ashes treated in a rotary kiln

DEFF Research Database (Denmark)

Hyks, Jiri; Nesterov, Igor; Mogensen, Erhardt

2011-01-01

Leaching from municipal solid waste incineration bottom ash treated in a rotary kiln was quantified using a combination of lab-scale leaching experiments and geochemical modelling. Thermal treatment in the rotary kiln had no significant effect on the leaching of Al, Ba, Ca, Mg, Si, Sr, Zn, sulfate...... the thermal treatment. Overall, rotary kiln thermal treatment of bottom ashes can be recommended to reduce the leaching of Cu, Pb, Cl and DOC; however, increased leaching of Cr and Mo should be expected....

Effectiveness of various irrigation activation protocols and the self-adjusting file system on smear layer and debris removal.

Science.gov (United States)