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Sample records for clinical crown length

  1. Influence of implant position on clinical crown length and peri-implant soft tissue dimensions at implant-supported single crowns replacing maxillary central incisors

    DEFF Research Database (Denmark)

    Peng, Min; Fei, Wei; Hosseini, Mandana;

    2013-01-01

    The aims of the present study were to evaluate the influence of implant position on clinical crown length and marginal soft tissue dimensions at implant-supported single crowns of maxillary central incisors, and to validate the papilla index score (PIS). Twenty-five patients, who had lost one...

  2. Evaluation of changes in clinical crown length of lower anterior teeth after treatment with Frankel-2′s appliance

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    Arthur C Vasconcelos

    2014-01-01

    Conclusion: It can be concluded that there is a tendency to increase the clinical crown of lower anterior teeth throughout the years after the mandibular advancement treatment by using functional devices, rejecting the null hypotheisis.

  3. Crown lengthening: a clinical review.

    Science.gov (United States)

    Talbot, T R; Briggs, P F; Gibson, M T

    1993-09-01

    The use of crown lengthening surgery as an adjunct to restorative therapy was first suggested by Rosen and Gitnick. This technique is designed to increase the clinical crown heights of teeth requiring restoration following extensive wear through attrition, abrasion and erosion. This loss of tooth tissue and resulting clinical crown height may be localized to a few teeth or affect the entire dentition. This clinical problem is reflected by the increasing number of reports of treatment of the worn dentition.

  4. Comparison of Implant-Supported Crown Length Measured on Digitized Casts and Intraoral Radiographs

    NARCIS (Netherlands)

    Meijer, Henny J. A.; Telleman, Gerdien; Gareb, Chawan; Den Hartog, Laurens; Vissink, Arjan; Raghoebar, Gerry M.

    2012-01-01

    Correct measurement of crown length is important for calculating the crown-implant ratio. The aim of this study was to compare the length of implant-supported crowns measured on digitized casts and intraoral radiographs. Crown lengths were studied in 50 patients with 86 implant-supported crowns in t

  5. Clinical crown lengthening to improve implant results.

    Science.gov (United States)

    Kohner, J

    1992-01-01

    Clinical crown lengthening is used as an adjunct to implant procedures, and can help provide a better long-term prognosis by establishing proper occlusal planes and aiding in preparation of the abutment teeth. Crown lengthening procedures may be especially useful when caries or a fracture extends below the gingival margin, compromising impression taking and marginal fit.

  6. Clinical crown lengthening in the esthetic zone.

    Science.gov (United States)

    Camargo, Paulo M; Melnick, Philip R; Camargo, Luciano M

    2007-07-01

    Periodontal surgical procedures consisting of gingival flaps and osseous recontouring are indicated for crown lengthening of several contiguous teeth in the esthetic zone; both in cases where restorations are required and in cases where no restorations are planned, such as in patients with excessive gingival display due to altered passive eruption. Forced tooth eruption via orthodontic extrusion is the technique of choice when clinical crown lengthening is necessary on isolated teeth in the esthetic zone.

  7. Changes of Root Length and Root-to-Crown Ratio after Apical Surgery

    DEFF Research Database (Denmark)

    von Arx, Thomas; Jensen, Simon S; Bornstein, Michael M

    2015-01-01

    the length of apicectomy and calculated the loss of root length and changes of RCR after apical surgery. METHODS: In a prospective clinical study, cone-beam computed tomography scans were taken preoperatively and postoperatively. From these images, the crown and root lengths of 61 roots (54 teeth in 47.......58 ± 1.43 mm (relative to the CBL). This amounted to a loss of 33.2% of clinical and 26% of anatomic root length. There was an overall significant difference between the tooth groups (P

  8. Clinical crown lengthening - a case report.

    Science.gov (United States)

    Lipska, Weronika; Lipski, Marcin; Lisiewicz, Małgorzata; Gala, Andrzej; Gronkiewicz, Krzysztof; Darczuk, Dagmara; Chomyszyn-Gajewska, Maria

    2015-01-01

    Maintaining healthy parodontium during teeth restoration procedures is an indispensable condition for obtain- ing regular functionning and esthetics. Thus, the knowledge of correct anatomy and the influence of filling and complement on paradontium tissue is vital. Difficulty in maintaining appropriate gingival biological width (GBW) is a frequent problem encountered in this type of reconstruction. Preservation of unchanged biological width conditions predictible treatment result and, what is more, lack of inflammatory lesions in marginal parodontium. The ideal situation for parodontium is localizing the filling/complement border supragingivaly, which is at least 3 mm from alveolar process edge. In the case, when the above conditions are impossible to fulfil, elongation of clinical crown is a metod of choice. The effect is possible to achieve by surgical treatment or combined orthodontic - surgical treatment. Surgical treatment is faster and preferred procedure for indirect reconstruction, where achieving high clinical crown is necessary. Three clinical cases of performing method of surgical clinical crown elongation were presented in the article. Performing the described procedure enables correct tooth crown reconstruction and, what is most important, keeping individual toothing.

  9. Surgical lengthening of the clinical tooth crown.

    Science.gov (United States)

    Planciunas, Liudvikas; Puriene, Alina; Mackeviciene, Grazina

    2006-01-01

    To understand why the crown lengthening may be desirable, a review of periodontal anatomy is in order. The odontologists know, but often underestimate importance of periodontal tissues health to restoration of defected teeth or dental arches. In order to avoid pathological changes, to predict treatment results more precisely, it is necessary to keep gingival biological width unaltered during teeth restoration. If there are less than 2 mm from restoration's margin to marginal bone clinical crown lengthening possibility should be considered in dental treatment plan. The choice depends on relationship of crown-root-alveolar bone and esthetical expectations. In order to keep margins of restoration supragingivally the distance from marginal bone to margins of restoration should not be less than 3 mm. Ideally the margins of restoration should be supragingivally or in the same level as marginal gingiva. When the margins of restoration are prepared subgingivally, the distance from marginal gingiva to margins of restoration should not be more than 0.7 mm. To continue dental treatment in operated area is recommended not earlier than in 4 weeks, and making restorations in esthetical area--not earlier than in 6 weeks.

  10. Crown lengthening: basic principles, indications, techniques and clinical case reports.

    Science.gov (United States)

    Yeh, Simon; Andreana, Sebastiano

    2004-11-01

    Sometimes, in order to properly restore teeth, surgical intervention in the form of a crown-lengthening procedure is required. Crown lengthening is a periodontal resective procedure, aimed at removing supporting periodontal structures to gain sound tooth structure above the alveolar crest level. Periodontal health is of paramount importance for all teeth, both sound and restored. For the restorative dentist to utilize crown lengthening, it is important to understand the concept of biologic width, indications, techniques and other principles. This article reviews these basic concepts of clinical crown lengthening and presents four clinical cases utilizing crown lengthening as an integral part of treatments, to restore teeth and their surrounding tissues to health.

  11. Crown lengthening in the maxillary anterior region: a 6-month prospective clinical study.

    Science.gov (United States)

    Deas, David E; Mackey, Scott A; Sagun, Ruben S; Hancock, Raymond H; Gruwell, Scott F; Campbell, Casey M

    2014-01-01

    The purpose of this study was to assess osseous parameters and stability of maxillary anterior teeth following crown lengthening surgery. Thirty-six patients requiring facial crown lengthening of 277 maxillary anterior and first premolar teeth were included. Presurgical and intraoperative clinical measurements were recorded at baseline and 1, 3, and 6 months postsurgery at midfacial, mesiofacial, and distofacial line angles. The data presented here suggest that when crown lengthening anterior maxillary teeth, the distance between the desired gingival margin and alveolar crest is usually insufficient to allow for biologic width. In addition, there is significant tissue rebound that may stabilize by 6 months. Tissue rebound appears related to flap position relative to the alveolar crest at suturing. These findings suggest that clinicians should establish proper anterior crown length with osseous resection.

  12. [An esthetic crown lengthening technic of the clinical crown. Rapid orthodontic extrusion].

    Science.gov (United States)

    Blase, D; Bercy, P

    1993-01-01

    Rapid orthodontic root extrusion is an esthetic technique for clinical crown lengthening. Associated with periodontal surgery, it exposes subgingival lesions and preserves an harmonious gingivo-osseous morphology. This conservative technique is easy to apply by the general dentist as it requires non specialised material.

  13. An Update on Crown Lengthening. Part 2: Increasing Clinical Crown Height to Facilitate Predictable Restorations.

    Science.gov (United States)

    Kalsi, Harpoonam Jeet; Bomfim, Deborah Iola; Darbar, Ulpee

    2015-04-01

    This is the second paper in this two-part series. Paper one provided an overview of managing gingival tissue excess and paper two will focus on increasing clinical crown height to facilitate restorative treatment. Crown lengthening is a surgical procedure aimed at the removal of gingival tissue with or without adjunctive bone removal. The different types of procedure undertaken will be discussed over the two papers. In order to provide predictable restorations, care must be taken to ensure the integrity of the margins. If this is not taken into account it can lead to an impingement on the biologic width, which may in turn lead to chronic inflammation resulting in recession or the development of periodontal problems which can be hard to manage. Clinical Relevance: This paper aims to reinforce the need for thorough diagnosis and treatment planning and provides an overview of the various procedures that can be undertaken.

  14. Odontoplasty associated with clinical crown lengthening in management of extensive crown destruction

    Directory of Open Access Journals (Sweden)

    Márcio K da Cruz

    2012-01-01

    Full Text Available Aim: The aim of this study was to evaluate the clinical outcome of teeth submitted to odontoplasty during clinical crown lengthening surgery (CCLS, when compared to their contralateral non-operated teeth. Materials and Methods: Fourteen patients submitted to odontoplasty during CCLS were evaluated according to plaque index, bleeding on probing, probing depth and final restoration outcome (total success, relative success and failure. Results: The mean follow-up period was 13.57 (± 8.00 months, and ranged from 6 to 24 months. Twelve cases presented total success of the final rehabilitation and 2 cases presented relative success. The cases of relative success were due to the necessity for a new periodontal intervention (scalling. No differences were observed with respect to periodontal parameters (P>0.05 and the patients that showed relative success presented generalized poor oral hygiene. Conclusions: The odontoplasty during clinical crown lengthening surgery is a feasible procedure in the management of extensive crown destruction.

  15. Aesthetic Surgical Crown Lengthening Procedure

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    Pablo Santos de Oliveira

    2015-01-01

    Full Text Available The aim of this case report was to describe the surgical sequence of crown lengthening to apically reposition the dentogingival complex, in addition to an esthetic restorative procedure. Many different causes can be responsible for short clinical crown. In these cases, the correct execution of a restorative or prosthetic rehabilitation requires an increasing of the crown length. According to the 2003 American Academy of Periodontology (Practice Profile Survey, crown lengthening is the most habitual surgical periodontal treatment.

  16. Aesthetic Surgical Crown Lengthening Procedure.

    Science.gov (United States)

    de Oliveira, Pablo Santos; Chiarelli, Fabio; Rodrigues, José A; Shibli, Jamil A; Zizzari, Vincenzo Luca; Piattelli, Adriano; Iezzi, Giovanna; Perrotti, Vittoria

    2015-01-01

    The aim of this case report was to describe the surgical sequence of crown lengthening to apically reposition the dentogingival complex, in addition to an esthetic restorative procedure. Many different causes can be responsible for short clinical crown. In these cases, the correct execution of a restorative or prosthetic rehabilitation requires an increasing of the crown length. According to the 2003 American Academy of Periodontology (Practice Profile Survey), crown lengthening is the most habitual surgical periodontal treatment.

  17. Estimation of Gestational Age According to Crown-Rump Length in Nepalese Population: A Comparison with Previously Published Nomograms

    OpenAIRE

    B. Raj Joshi

    2009-01-01

    Background/Objective: This study was performed to construct an institution specific crown-rump length (CRL) nomogram and to compare its ability to predict gestational age with previously published nomograms. "nPatients and Methods: A regression model was developed for estimation of gestational age using CRL measurements of 123 singleton fetuses in the Nepalese population. Measurements were obtained by placing the calipers of the ultrasound machine from the crown to the rump. The appropri...

  18. Photoelastic Analysis of Fixed Partial Prosthesis Crown Height and Implant Length on Distribution of Stress in Two Dental Implant Systems

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    Evandro Portela Figueirêdo

    2014-01-01

    Full Text Available The aim of this study was to evaluate by photoelastic analysis stress distribution on short and long implants of two dental implant systems with 2-unit implant-supported fixed partial prostheses of 8 mm and 13 mm heights. Sixteen photoelastic models were divided into 4 groups: I: long implant (5×11 mm (Neodent, II: long implant (5×11 mm (Bicon, III: short implant (5×6 mm (Neodent, and IV: short implants (5×6 mm (Bicon. The models were positioned in a circular polariscope associated with a cell load and static axial (0.5 Kgf and nonaxial load (15°, 0.5 Kgf were applied to each group for both prosthetic crown heights. Three-way ANOVA was used to compare the factors implant length, crown height, and implant system (α=0.05. The results showed that implant length was a statistically significant factor for both axial and nonaxial loading. The 13 mm prosthetic crown did not result in statistically significant differences in stress distribution between the implant systems and implant lengths studied, regardless of load type (P>0.05. It can be concluded that short implants showed higher stress levels than long implants. Implant system and length was not relevant factors when prosthetic crown height were increased.

  19. Crown-rump length discordance in the first trimester: a predictor of adverse outcome in twin pregnancies?

    DEFF Research Database (Denmark)

    Johansen, Mathias; Oldenburg, A.; Rosthøj, Susanne;

    2014-01-01

    OBJECTIVES: To evaluate the usefulness of first-trimester crown-rump length (CRL) discordance in predicting adverse outcome in twin pregnancies. METHODS: This retrospective study included a large cohort retrieved from local ultrasound databases at 14 obstetric departments in Denmark, comprising a...

  20. [Clinical evaluation of gingival tissue restored with stainless steel crown].

    Science.gov (United States)

    Chao, D D; Tsai, T P; Chen, T C

    1992-12-01

    The use of stainless steel crown for the restoration of primary molars is widely accepted in pediatric dentistry. There has been a concern regarding their effect on the health of the gingival tissue. It is a possibility that the preformed crown may be a contributing cause of gingivitis. This study evaluated one hundred and thirty-seven crowns in forty-five patients who had received pedodontic treatment at Chang Gung Memorial Hospital. The results indicated that the majority of stainless steel crowns had one or more defects, with crown crimping being the most common error. According to what the paired t-test showed, non-ideal crowns indicated that the gingival index was significantly higher than the entire mouth and control teeth. However the supragingival plaque accumulation of these teeth was significant lower than the entire mouth and control teeth. There was only a moderate positive correlation between supragingival plaque and gingivitis. The operator is necessary to adapt the stainless steel crown margin as closely as possible to the tooth and to avoid the mechanical defect of a crown. It minimizes the irritation of gingival tissue and diminishes the bacterial adherence of subgingival plaque, therefore preserving the health of gingival tissue.

  1. Intrauterine position affects fetal weight and crown-rump length throughout gestation.

    Science.gov (United States)

    Jang, Y D; Ma, Y L; Lindemann, M D

    2014-10-01

    To investigate the effect of intrauterine positions on fetal growth throughout gestation, data from a total of 65 gilts (n = 784 fetuses) that were slaughtered at assigned days of gestation (d 43, 58, 73, 91, 101, and 108) on a project to evaluate fetal mineral deposition were used. Placenta units were removed from the uterus, and position, sex, weight, and crown-rump length (CRL) of each fetus were recorded. Fetuses were classified into 5 categories within a uterine horn for the absolute intrauterine position: the ovarian end (OE) of the uterine horn, next to the ovarian end (NOE), the middle (MD), next to the cervical end (NCE), and the cervical end (CE), and also classified for the relative fetal position with respect to the sex of adjacent fetuses. Fetuses at the OE and NOE of the uterine horn tended to be heavier (P = 0.06) and longer (P gestation. Fetuses at the OE of the uterine horn were also heavier and longer than those at the MD and NCE of the uterine horn at d 101 and 108 of gestation (P gestation (P gestation. Fetal weight was highly correlated with CRL at all gestational ages (P pigs grow faster than female pigs even before birth.

  2. Comparison of Clinical Effects of Au-Pt Based and Ni-Cr Based Porcelain Crowns

    Institute of Scientific and Technical Information of China (English)

    Li-chun Wu; Ye Shi; Teng Ma

    2012-01-01

    Objective To compare the long-term clinical effects of two kinds of crowns and bridges made of porcelain fused to Au-Pt alloy and Ni-Cr alloy.Methods A total of 131 teeth (64 patients) were rehabilitated using porcelain-fused-to-metal crowns,among which 59 were rehabilitated with Au-Pt alloy metal ceramic crown and 72 with Ni-Cr alloy metal ceramic crown.The porcelain fracture,shade,marginal adaptation,gingival discoloration,and gingival status after finishing restoration and 36 months of follow-up were evaluated.Results After 36 months of restoration,porcelain fused to Au-Pt alloy crown showed better clinical effects than porcelain fused to Ni-Cr alloy crown in shade,marginal adaptation,gingival discoloration,as well as gingival status (all P<0.05).Conclusion The Au-Pt alloy ceramic crown is superior to Ni-Cr alloy ceramic crown in long-term clinical effects.

  3. Clinical assessment of enamel wear caused by monolithic zirconia crowns.

    Science.gov (United States)

    Stober, T; Bermejo, J L; Schwindling, F S; Schmitter, M

    2016-08-01

    The purpose of this study was to measure enamel wear caused by antagonistic monolithic zirconia crowns and to compare this with enamel wear caused by contralateral natural antagonists. Twenty monolithic zirconia full molar crowns were placed in 20 patients. Patients with high activity of the masseter muscle at night (bruxism) were excluded. For analysis of wear, vinylpolysiloxane impressions were prepared after crown incorporation and at 6-, 12-, and 24-month follow-up. Wear of the occlusal contact areas of the crowns, of their natural antagonists, and of two contralateral natural antagonists (control teeth) was measured by use of plaster replicas and a 3D laser-scanning device. Differences of wear between the zirconia crown antagonists and the control teeth were investigated by means of two-sided paired Student's t-tests and linear regression analysis. After 2 years, mean vertical loss was 46 μm for enamel opposed to zirconia, 19-26 μm for contralateral control teeth and 14 μm for zirconia crowns. Maximum vertical loss was 151 μm for enamel opposed to zirconia, 75-115 μm for control teeth and 60 μm for zirconia crowns. Statistical analysis revealed significant differences between wear of enamel by zirconia-opposed teeth and by control teeth. Gender, which significantly affected wear, was identified as a possible confounder. Monolithic zirconia crowns generated more wear of opposed enamel than did natural teeth. Because of the greater wear caused by other dental ceramics, the use of monolithic zirconia crowns may be justified.

  4. Clinical assessment of enamel wear caused by monolithic zirconia crowns.

    Science.gov (United States)

    Stober, T; Bermejo, J L; Schwindling, F S; Schmitter, M

    2016-08-01

    The purpose of this study was to measure enamel wear caused by antagonistic monolithic zirconia crowns and to compare this with enamel wear caused by contralateral natural antagonists. Twenty monolithic zirconia full molar crowns were placed in 20 patients. Patients with high activity of the masseter muscle at night (bruxism) were excluded. For analysis of wear, vinylpolysiloxane impressions were prepared after crown incorporation and at 6-, 12-, and 24-month follow-up. Wear of the occlusal contact areas of the crowns, of their natural antagonists, and of two contralateral natural antagonists (control teeth) was measured by use of plaster replicas and a 3D laser-scanning device. Differences of wear between the zirconia crown antagonists and the control teeth were investigated by means of two-sided paired Student's t-tests and linear regression analysis. After 2 years, mean vertical loss was 46 μm for enamel opposed to zirconia, 19-26 μm for contralateral control teeth and 14 μm for zirconia crowns. Maximum vertical loss was 151 μm for enamel opposed to zirconia, 75-115 μm for control teeth and 60 μm for zirconia crowns. Statistical analysis revealed significant differences between wear of enamel by zirconia-opposed teeth and by control teeth. Gender, which significantly affected wear, was identified as a possible confounder. Monolithic zirconia crowns generated more wear of opposed enamel than did natural teeth. Because of the greater wear caused by other dental ceramics, the use of monolithic zirconia crowns may be justified. PMID:27198539

  5. [Long-term clinical results with Procera AllCeram full-ceramic crowns].

    Science.gov (United States)

    Galindo, Martha L; Hagmann, Edgar; Marinello, Carlo P; Zitzmann, Nicola U

    2006-01-01

    The aim of this prospective clinical study was to investigate the long-term survival rate of Procera AllCeram full-ceramic crowns, which were fabricated with aluminiumoxide cores. In 50 patients, 155 Procera crowns with a conventional or reduced core (porcelain collar) were placed on natural abutment teeth. 78% of this group (39 patients with 135 crowns) were examined between May and August 2005 according to the modified USPHS-Criteria. These crowns had been in place for a period of one to 92 months (mean 55 months). Almost half of the crowns were located in the molar region, while 28% were premolars and 24% anterior crowns. Due to one crown fracture the cumulative survival rate was 99% after five and seven years. The clinical success was achieved irrespective of the tooth position, tooth vitality, the preparation margin and the cementum medium used (composite resin or glasionomer cement). In addition, survival was neither influenced by the core design with reduced or conventional margin nor by the core thickness, which measured regularly 0.6 mm in the majority of the specimens. Based on the present findings, it can be concluded that Procera AllCeram is a predictable technique for metal-free, esthetic full-ceramic crowns in the anterior and posterior region. PMID:16989114

  6. Clinical effectiveness and periodontal index analysis of crown lengthening surgery for molar crown restoration%牙冠延长术用于磨牙冠修复的临床疗效及牙周指标分析

    Institute of Scientific and Technical Information of China (English)

    杜莉莉; 林晓萍; 靳赢; 韩佳佳; 张春辉

    2011-01-01

    Objective To analyse clinical effectiveness and periodontal index changes of crown lengthening surgery for molar crown restoration. Methods Choose 26 molar cases whose clinical crown length could rot satisfy the complete coronal restoration requirements, and whose crown prosthesis repeatedly fell off or whose broken biological width lead to gum inflammation, implement crown lengthening surgery,and perform crown restoration 6 weeks after surgery. At different time we observe changes in clinical crown length, record relevant periodontal index and analyse and evaluate clinical effect of the postoperative crown restoration. Results Postoperative clinical crown length had obvious short-term effect. The experiment groups postoperative periodontal index were superior to preoperative index(P0.05) .and remained relatively stable in one-year observation period (P>0.05). The retention of crown prosthesis was better, and the margin was fitted well and relatively stable to the margin of gingival. Conclusions For clinical short-crown molars, crown lengthening surgery is an effective method which can improve the full crown repairing effect and promote health of periodontal tissue.%目的 分析牙冠延长术用于磨牙全冠修复的临床疗效及牙周指数变化.方法 选择26颗临床冠长度过小无法满足全冠修复固位要求的磨牙,以及固位不良反复脱落,破坏了生物学宽度造成牙龈炎症的全冠修复失败病例,施以牙冠延长术,术后6周行固定全冠修复.观察不同时段临床冠长度的变化,记录各相关牙周指数并进行分析,评估术后全冠修复的临床效果.结果 术后短期内临床冠长度增加效果确切;试验组术后的各项牙周指数均优于术前(P0.05),在1年的观察期内保持相对稳定(P>0.05);全冠修复体的固位良好,边缘密合,龈缘与冠缘的位置关系相对稳定.结论 对于临床冠过短的磨牙,冠延长术是改善全冠修复效果,促进牙周组织健康的有效方法.

  7. Surgical extrusion technique for clinical crown lengthening: report of three cases.

    Science.gov (United States)

    Kim, Chang-Sung; Choi, Seong-Ho; Chai, Jung-Kiu; Kim, Chong-Kwan; Cho, Kyoo-Sung

    2004-10-01

    Although a number of techniques have been proposed for clinical crown lengthening procedures, all have some limitation in terms of function and esthetics. This report presents the clinical and radiographic results of a surgical extrusion technique for clinical crown lengthening. Atraumatic surgical extrusion using a specially designed instrument (Periotome) was performed in three cases in which it was expected that extensive resective osseous surgery would have to be used for crown lengthening. Full-thickness mucoperiosteal flaps were raised both labially and palatally. The tooth was carefully luxated and extruded to the desired position without damaging the marginal bone area or root apex. No rigid splint was applied. Clinical examinations performed for more than 1 year after surgery revealed probing depths crown lengthening; it does not induce functional or esthetic deformities, especially in the anterior region.

  8. Multidisciplinary and esthetic approach to clinical crown lengthening: report of a case.

    Science.gov (United States)

    Ngan, P; Knobloch, L

    1993-12-01

    This paper describes the combined efforts of an orthodontist, periodontist, and a restorative dentist to save an unrestorable tooth by clinical crown lengthening. A maxillary lateral incisor, originally treatment planned for extraction, was treated with orthodontic extrusion, circumferential fiberotomy, and metal-ceramic crown restoration. To maximize the esthetic appearance of the tooth during orthodontic treatment, an acrylic resin facing was designed together with the orthodontic appliance used to facilitate vertical extrusion. Clinical crown lengthening may be used as an alternative approach to the treatment of severely broken down anterior teeth.

  9. Maxillary and mandibular anterior crown width/height ratio and its relation to various arch perimeters, arch length, and arch width groups

    Science.gov (United States)

    Shahid, Fazal; Alam, Mohammad Khursheed; Khamis, Mohd Fadhli

    2015-01-01

    Objective: To investigate the maxillary and mandibular anterior crown width/height ratio and its relation to various arch perimeters, arch length, and arch width (intercanine, interpremolar, and intermolar) groups. Materials and Methods: The calculated sample size was 128 subjects. The crown width/height, arch length, arch perimeter, and arch width of the maxilla and mandible were obtained via digital calliper (Mitutoyo, Japan). A total of 4325 variables were measured. The sex differences in the crown width and height were evaluated. Analysis of variance was applied to evaluate the differences between arch length, arch perimeter, and arch width groups. Results: Males had significantly larger mean values for crown width and height than females (P ≤ 0.05) for maxillary and mandibular arches, both. There were no significant differences observed for the crown width/height ratio in various arch length, arch perimeter, and arch width (intercanine, interpremolar, and intermolar) groups (P ≤ 0.05) in maxilla and mandible, both. Conclusions: Our results indicate sexual disparities in the crown width and height. Crown width and height has no significant relation to various arch length, arch perimeter, and arch width groups of maxilla and mandible. Thus, it may be helpful for orthodontic and prosthodontic case investigations and comprehensive management. PMID:26929686

  10. Comparing Laser and Scalpel for Soft Tissue Crown Lengthening: A Clinical Study.

    Science.gov (United States)

    Farista, Sana; Kalakonda, Butchibabu; Koppolu, Pradeep; Baroudi, Kusai; Elkhatat, Esam; Dhaifullah, Essam

    2016-02-24

    Crown lengthening procedure is aimed at exposure of sufficient crown structure accomplished by a gingivectomy, an apically positioned flap with osseous resection or the use of lasers. Our present clinical study is aimed to assess the clinical effectiveness of a diode laser for functional crown lengthening procedure and to compare it with the conventional procedure using the scalpel. Fourteen patients including males and females, aged 20- 40 years were recruited and divided into two groups to undergo crown lengthening either with the scalpel or the laser. The data obtained was analyzed for intergroup comparison with an Unpaired t-test and intragroup comparison was determined by ANOVA.Analysis of the intergroup results for pain showcased that there was a significant difference (Pcrown lengthening performed with the scalpel.

  11. Enamel wear caused by monolithic zirconia crowns after 6 months of clinical use.

    Science.gov (United States)

    Stober, T; Bermejo, J L; Rammelsberg, P; Schmitter, M

    2014-04-01

    The purpose of this study was to evaluate enamel wear caused by monolithic zirconia crowns and to compare this with enamel wear caused by contralateral natural antagonists. Twenty monolithic zirconia crowns were placed in 20 patients requiring full molar crowns. For measurement of wear, impressions of both jaws were made at baseline after crown cementation and at 6-month follow-up. Mean and maximum wear of the occlusal contact areas of the crowns, of their natural antagonists and of the two contralateral natural antagonists were measured by the use of plaster replicas and 3D laser scanning methods. Wear differences were investigated by the use of two-sided paired Student's t-tests and by linear regression analysis. Mean vertical loss (maximum vertical loss in parentheses) was 10 (43) μm for the zirconia crowns, 33 (112) μm for the opposing enamel, 10 (58) μm for the contralateral teeth and 10 (46) μm for the contralateral antagonists. Both mean and maximum enamel wear were significantly different between the antagonists of the zirconia crowns and the contralateral antagonists. Gender and activity of the masseter muscle at night (bruxism) were identified as possible confounders which significantly affected wear. Under clinical conditions, monolithic zirconia crowns seem to be associated with more wear of opposed enamel than are natural teeth. With regard to wear behaviour, clinical application of monolithic zirconia crowns is justifiable because the amount of antagonistic enamel wear after 6 months is comparable with, or even lower than, that caused by other ceramic materials in previous studies.

  12. Clinical and Radiographic Evaluation of Pulpotomized Primary Molars Restored with Stainless Steel Crown and Amalgam

    Directory of Open Access Journals (Sweden)

    Haghgoo R.

    2011-08-01

    Full Text Available Statement of Problem: Pulpotomy is the most common pulp treatment in primary teeth. Final restoration of the pulpotomized primary molar can affect the success rate of treatment. Purpose: The aim of this study was to evaluate the success rate of formocresol pulpotomy in primary molars restored with stainless steel crowns as compared to those restored with amalgam.Materials and Method: In this randomized clinical trial study, 110 primary molars to be treated with pulpotomy were treated by a conventional pulpotomy technique. Then these teeth were randomly divided into 2 groups: amalgam and crown. 55 teeth were restored by stainless steel crown and 55 by amalgam. The clinical and radiographic evaluation was done at 6-12-24 months. The data were analyzed by Exact Fisher test.Results: During the 6 months of evaluation, no clinical and radiographic failure was seen. In the 12 months of follow up in the amalgam group, 1 case showed swelling and furcal radiolucency. During the 24 months of evaluation, mobility was seen in 2 teeth in the crown group, and in the amalgam group radiolucency was seen in 1 case, mobility in 1 case, and internal resorption in 1 tooth. Exact Fisher test showed that there was no significant difference in the success rate of pulpotomized molars restored by stainless steel crown and amalgam.Conclusion: If the tooth is selected correctly for pulpotomy, SSC and amalgam restoration can be used as the final restoration.

  13. Effect of preparation surface area on the clinical outcome of full veneer crowns in dogs.

    Science.gov (United States)

    Riehl, Jessica; Soukup, Jason W; Collins, Caitlyn; Siverling, Sarah; Ploeg, Heidi-Lynn; Snyder, Christopher J

    2014-01-01

    Crown therapy is commonly used in veterinary medicine to provide support to teeth which have previously fractured, received root canal therapy, have significant wear, or experienced other detrimental removal of tooth substance. As with several aspects of veterinary medicine, many of the recommendations or guidelines for crown therapy originate from human dentistry, which are then transferred to veterinary patients. Due to the significant difference in the anatomy of teeth and function of the oral cavity between humans and dogs, these guidelines need to be studied to determine the appropriateness of their use in veterinary patients. This article evaluates the relationship between surface area of the preparation and clinical outcome of full veneer crown therapy of the canine tooth in dogs. Although there appeared to be a positive relationship between preparations with greater surface area and successful clinical outcome, it was not found to be statistically significant.

  14. Clinical performance - a reflection of damage accumulation in ceramic dental crowns

    Energy Technology Data Exchange (ETDEWEB)

    Rekow, D.E. [Univ. of Medicine and Dentistry of New Jersey, Newark, NJ (United States). Dept. of Orthodontics; Thompson, V.P. [Univ. of Medicine and Dentistry of New Jersey, Newark, NJ (United States). New Jersey Dental School

    2001-07-01

    All-ceramic dental crowns have tremendous appeal for patients - their esthetics nearly match those of natural teeth. Unfortunately, the most esthetic materials are brittle and, consequently, are vulnerable to damage relating to shaping which is exacerbated during cyclic loading during normal chewing. Clinical performance of all-ceramic dental prostheses are directly dependent on damage introduced during fabrication and during fatigue loading associated with function. The accumulation of damage results in unacceptably high failure rates (where failure is defined as a complete fracture requiring replacement of the prosthesis). The relation between shaping damage and fatigue damage on clinical performance of all-ceramic dental crowns was investigated. Materials used commercially for all-ceramic crowns and investigated in this study included a series of different microstructures of machinable glass ceramics (Corning), aluminas and porcelains (Vita Zahnfabrik), and zirconia (Norton). As monolithic materials, strong, tough, fatigue-resistant materials are not sufficiently esthetic for crowns. Crowns fabricated from monolithic esthetic materials have high failure rates. Layering ceramics could provide acceptable strength through management of damage accumulation. (orig.)

  15. Estimation of Gestational Age According to Crown-Rump Length in Nepalese Population: A Comparison with Previously Published Nomograms

    Directory of Open Access Journals (Sweden)

    B. Raj Joshi

    2009-11-01

    Full Text Available Background/Objective: This study was performed to construct an institution specific crown-rump length (CRL nomogram and to compare its ability to predict gestational age with previously published nomograms. "nPatients and Methods: A regression model was developed for estimation of gestational age using CRL measurements of 123 singleton fetuses in the Nepalese population. Measurements were obtained by placing the calipers of the ultrasound machine from the crown to the rump. The appropriateness of previously established CRL nomograms for predicting the gestational age was assessed in the Nepalese population to determine comparability between nomograms. "nResults: CRL corresponds to Robinson's nomogram up to 9 weeks of gestational age. There is a deficiency of 2mm at 10 weeks, 5 mm at 11 weeks and 8 mm at 12 weeks. "nConclusion: CRL measurements are used as a reliable method for estimation of the gestational age as well as a baseline for comparing gestational ages later. CRL corresponds to Robinson's nomogram up to 9 weeks gestational age. There is a deficiency of 2-8 mm from 10-12 weeks gestational age. Difference with the established nomograms may be due to ethnic differences of the fetal development. After 12 weeks, CRL measurement is unreliable due to flexion of the fetus.

  16. Observation of clinical effect of the short crown molars with short-post inlay-crown restoration%短桩钉嵌体冠修复短冠磨牙的临床效果观察

    Institute of Scientific and Technical Information of China (English)

    徐建红; 张蓉

    2012-01-01

    Objective To investigate the indications and restorative applications of a short-post inlay-crown restoration, and to observe the clinical significance of the short crown molar restoration using a short-post inlay-crown. Methods 270 endodontic -treated molars with an occlusogingival distance less than 4mm (i.e. the short crown molar) were randomly divided into the followingthree groups: Group A - short -post inlay -crown restoration; Group B -conventional post inlay-crown restoration; and Group C - inlay-crown restoration with pulp chamber retention. All cases were followed up regularly from two to five years. Results The clinical outcome of 270 molars with inlay -crown restorations was satisfactory. However, gingivitis and/or the lack of edge adhesion was observed in a few cases. The prosthetic effect of Group A and Group B was significantly better than Group C (P0.05). The two groups of inlay-crowns with different lengths of post presented a similar prosthetic effect, and were both better than those in Group C -subjects with inlay-crown restorations with pulp chamber retention. Conclusion The short-post inlay-crown restoration seems to be a simple, affordable and reliable method to restore short crown molars.%目的 探讨短桩钉嵌体冠修复的适应证和修复方法,观察短桩钉嵌体冠修复短冠磨牙的临床意义.方法 对270颗经完善根管治疗的合龈距<4mm的短冠磨牙,随机分为3组,A组:短桩钉嵌体冠修复;B组:常规桩钉预备的嵌体冠修复;C组:对照组不作桩钉预备的利用髓腔固位的嵌体冠修复,每组90颗,定期复查,随访观察2~5年,评价修复效果.结果 270颗磨牙经嵌体冠修复治疗后获得满意效果,个别病例出现牙龈炎和或边缘不密合的情况.A组和B组修复效果明显高于C组,(分别为P<0.01和P<0.05)有显著差异性;A组和B组修复效果比较,(P>0.05)没有显著性差异.表明两组不同桩长度的嵌体冠修复效果并无统计学

  17. Individual lithium disilicate crowns in a full-arch, implant-supported rehabilitation: a clinical report.

    Science.gov (United States)

    Maló, Paulo; de Sousa, Sérgio Tavares; De Araújo Nobre, Miguel; Moura Guedes, Carlos; Almeida, Ricardo; Roma Torres, António; Legatheaux, João; Silva, António

    2014-08-01

    This clinical report presents the clinical outcome of a maxillary full-arch implant-supported fixed rehabilitation with lithium disilicate reinforced glass ceramic monolithic crowns opposing a mandibular metal-acrylic implant-supported fixed rehabilitation in a 62-year-old woman. Eight implants were successfully placed (four maxillary, four mandibular), and no complications occurred in the postoperative or maintenance periods. Six months after delivery, the maxillary and mandibular prostheses were found to be clinically, biologically, and mechanically stable, and the patient was satisfied with the esthetics and her ability to function. Although the present indications for the use of lithium disilicate are still restricted to tooth-borne restorations, it is possible to successfully rehabilitate edentulous patients through implant-supported fixed prostheses using lithium disilicate reinforced glass ceramic monolithic crowns.

  18. Estimation of gestational age from measurement of crown-rump length with transvaginal sonography in early pregnancy

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Hyun Ju; Lee, Young Ho; Kim, Young Hwa [Cheil General Hospital, Seoul (Korea, Republic of)

    1994-12-15

    Estimation of gestational age using crown-rump length (CRL) has been considered to be relatively accurate. The purpose of this study was to determine the relationship between the gestational age (GA) and the CRL seen ontransvaginal sonography and to improve the gestational dating creteria. One hundred and ninety five patients with known date of conception, who were pregnant between February 1990 and December 1992, were examined with high resolution transvaginal ultrasonography. There was a linear relationship between the CRL and the GA from the 27th to the 56th day of ovulation. It was defined by equation, as GA=0.97xCRL+42.4 (r=0.95, p<0.0001). Regression values with 95% confidence limit for CRL were +3.9-4.0 days. Comparison of regression lines between the data from the natural cycle group (N=53) and those from the hormonally treated group (N=142) was performed. There was no statistically significant difference between the two groups (analysis of convariance, p>0.05) In conclusion, trasvaginal sonography was useful in the determination of the GA in the early pregnancy from the 27th day of ovulation up to the 56th day. A new reference chart is provided for the estimation of gestational age according to the CRL

  19. Five-year results of a prospective randomised controlled clinical trial of posterior computer-aided design-computer-aided manufacturing ZrSiO4 -ceramic crowns.

    Science.gov (United States)

    Passia, N; Stampf, S; Strub, J R

    2013-08-01

    The aim of this prospective randomised controlled clinical trial was to evaluate the clinical outcome of shrinkage-free ZrSiO4 -ceramic full-coverage crowns on premolars and molars in comparison with conventional gold crowns over a 5-year period. Two hundred and twenty-three patients were included and randomly divided into two treatment groups. One hundred and twenty-three patients were restored with 123 ZrSiO4 -ceramic crowns, and 100 patients received 100 gold crowns, which served as the control. All crowns were conventionally cemented with glass-ionomer cement. After an observation period of 6, 12, 24, 36, 48 and 60 months, the survival probability (Kaplan-Meier) for the shrinkage-free ZrSiO4 -ceramic crowns was 98·3%, 92·0%, 84·7%, 79% and 73·2% and for the gold crowns, 99%, 97·9%, 95·7%, 94·6% and 92·3%, respectively. The difference between the test and control group was statistically significant (P = 0·0027). The gold crowns showed a better marginal integrity with less marginal discoloration than the ceramic crowns. The most common failure in the ceramic crown group was fracture of the crown. The 60-month results of this prospective randomised controlled clinical trial suggest that the use of these shrinkage-free ZrSiO4 -ceramic crowns in posterior tooth restorations cannot be recommended.

  20. Effect of continuing or stopping smoking during pregnancy on infant birth weight, crown-heel length, head circumference, ponderal index, and brain:body weight ratio.

    Science.gov (United States)

    Lindley, A A; Becker, S; Gray, R H; Herman, A A

    2000-08-01

    The objective of this study was to determine whether stopping smoking between the first prenatal care visit and the 32nd week of pregnancy affects the smoking-associated changes in five infant anthropometric indices. The study population consisted of 15,185 births in the Swedish Medical Birth Register from 1991 and 1992. The associations between birth weight, crown-heel length, head circumference, ponderal index, brain:body weight ratio, maternal smoking status at the first prenatal care visit and at 32 weeks' gestation, and other maternal and infant characteristics were assessed using multivariate linear regression. The infants of 946 women who stopped smoking before week 32 of pregnancy were statistically indistinguishable from the 9,802 infants of nondaily smokers in terms of birth weight, head circumference, and brain:body weight ratio, but they retained a significant deficit in crown-heel length of 0.23 cm (standard error, 0.08) and a significant elevation in ponderal index of 0.027 (standard error, 0.009). In this study, stopping smoking between the first prenatal care visit and week 32 of pregnancy prevented smoking-associated deficits in infant birth weight, head circumference, and brain:body weight ratio, but did not completely prevent deficits in crown-heel length in comparison with nonsmokers' infants of the same age, and did not prevent elevation of ponderal index in comparison with nonsmokers' infants of the same weight and age. PMID:10933268

  1. Biologic rationale of esthetic crown lengthening using innovative proportion gauges.

    Science.gov (United States)

    Fletcher, Paul

    2011-01-01

    Research shows that practitioners tend to underestimate the amount of tooth structure that must be exposed during a crown lengthening procedure. In the anterior portion of the mouth, this can lead to biologic width problems and subsequent cosmetic issues. This paper presents a biologically based, step-by-step approach to periodontal esthetic crown lengthening. Using a series of innovative measuring gauges, the ideal clinical crown length of a tooth as well as the proper occlusogingival placement of the interproximal papilla will be determined based on established, documented tooth proportion relationships. The biologic crown length of the tooth, defined as the distance from the incisal edge to the bone crest, will subsequently be determined as a function of the clinical crown length, with the ultimate goals being adequate tooth structure for the placement of a restorative margin, establishment of a healthy dentogingival complex, and the placement of an esthetically pleasing definitive restoration.

  2. Crown lengthening procedures

    Directory of Open Access Journals (Sweden)

    AA. Khoshkhonejad

    1994-06-01

    Full Text Available Nowadays, due to recent developments and researches in dental science, it is possible to preserve and restore previously extracted cases such as teeth with extensive caries, fractured or less appropriate cases for crown coverage as well as teeth with external perforation caused by restorative pins. In order to restore the teeth with preservation of periodontium, we should know thoroughly physiological aspects of periodontium and protection of Biologic Width which is formed by epithelial and supracrestal connective tissue connections. Considering biologic width is one of the principal rules of teeth restoration, otherwise we may destruct periodontal tissues. Several factors are involved in placing a restoration and one of the most important ones is where the restoration margin is terminated. Many studies have been conducted on the possible effects of restoration margin on the gingiva and due to the results of these studies it was concluded that restoration margin should be finished supragingivally. However, when we have to end the restoration under Gingival Crest, First a healthy gingival sulcus is required. Also, we should not invade the biological width. Since a normal biologic with is reported 2 mm and sound tooth tissue should be placed at least 2 mm coronal to the epithelial tissue, the distance between sound tooth tissue and crown margin should be at least 4mm. Thus, performing crown lengthening is essential to increase the clinical crown length. Basically, two objectives are considered: 1 restorative 2 esthetic (gummy smile Surgical procedure includes gingivectomy and flap procedure. Orthodontic procedure involves orthodontic extrusion or force eruption technique which is controlled vertical movements of teeth into occlusion. Besides, this procedure can also used to extrude teeth defects from the gingival tissue. By crown lengthening, tooth extraction is not required and furthermore, adjacent teeth preparation for placing a fixed

  3. Three different surgical techniques of crown lengthening: A comparative study

    Directory of Open Access Journals (Sweden)

    Ramya Nethravathy

    2013-01-01

    Full Text Available Introduction: A short clinical crown may lead to poor retention form thereby leading to improper tooth preparation. Surgical crown lengthening procedure is done to increase the clinical crown length without violating the biologic width. Several techniques have been proposed for clinical crown lengthening which includes gingivectomy, apically displaced flap with or without resective osseous surgery, and surgical extrusion using periotome. Objective: The aim of this paper is to compare clinically the three different surgical techniques of crown lengthening procedures. Materials and Methods: Fifteen patients who reported to the department of Periodontology, were included in the study. Patients were randomly divided into three groups, which include patients who underwent gingivectomy (Group A, apically repositioned flap (Group B and surgical extrusion using periotome (Group C. Clinical measurements such as clinical crown length, gingival zenith, interdental papilla height were taken at baseline and at 3 rd month post-operatively. Results: Clinical and radiographic evaluation at 3 rd month suggest that surgical extrusion technique offers several advantages over the other conventional surgical techniques such as preservation of the interproximal papilla, gingival margin position and no marginal bone loss. Conclusions: This technique can be used to successfully treat a grossly damaged crown structure as a result of tooth fracture, dental caries and iatrogenic factors especially in the anterior region, where esthetics is of great concern.

  4. Dental crowns

    Science.gov (United States)

    ... you. The different types of crowns include: Stainless steel crowns: Are pre-made Work well as temporary crowns, especially for young children. The crown falls off when the child loses the baby tooth. Metal crowns: Hold up to chewing and teeth ...

  5. 牙冠延长术的临床应用%Clinical application of crown lengthening surgery

    Institute of Scientific and Technical Information of China (English)

    付兆江; 韩晓红

    2012-01-01

    牙冠延长术是近年来临床研究和推广的热门课题.临床上经常遇到因龋病、冠折等原因造成龈上牙体组织过短,给冠修复带来困难;如果冠边缘延伸至龈下过深,侵犯了生物学宽度,则易引起牙周问题.牙冠延长术利用生物学宽度的原理,应用翻瓣术联合牙槽骨修整的方法,延长牙冠或暴露龈下的牙体断端,其重点在于切除牙龈的同时,去除部分牙槽骨,以便在更根方的位置重建健康的牙周组织.%Crown lengthening surgery is a hot topic in clinic research. We often encountere too short teeth structures caused by caries or crown fracture. If the denture crown margin violate the biologic width periodontal problems will occur. Crown lengthening surgery, abide by the principle of biological width, using flap surgery combined with alveolar bone trimming can extend crown or expose the subgingival teeth structure by removing part of the alveolar bone and gum so as to reestablish healthy periodontal tissue in apical direction.

  6. Comparison of different methods involved in the planning of clinical crown lengthening surgery

    Directory of Open Access Journals (Sweden)

    Fabricio Batistin Zanatta

    2010-12-01

    Full Text Available There is little material in the literature that compares biological width measurements in periapical and bite-wings radiographs with clinical measurements. The purpose of this study was to compare measurements of biological width taken by three different methods which are frequently used for planning periodontal surgery - periapical radiograph, bite-wing radiograph and transperiodontal probing - with the trans-surgical measurements. Thirty-four sites from twenty-one subjects were analyzed. The intra-class correlation coefficients between measurements obtained trans-surgically (gold standard and those obtained by transperiodontal probing, periapical radiography and bite-wing radiography were determined. Average measurements were compared using the Wilcoxon test at a significance level of 0.05. Also, the frequency distribution of differences between test measurements and the gold standard was calculated. The results showed that transperiodontal probing (mean 2.05 mm was the most accurate measurement, as compared to the gold standard (mean 1.97 mm, with no statistically significant difference observed. On the other hand, periapical and bite-wing radiographic mean values (1.56 mm and 1.72 mm, respectively were smaller than the gold standard, with statistically significant differences (p < 0.05. It was concluded that transperiodontal probing was the most accurate measurement, as compared to the gold standard, followed by that obtained with the bite-wing radiograph. The clinical relevance of these results could be that planning for crown lengthening surgery should, preferably, include transperiodontal probing.

  7. Clinical evaluation of the biological width following surgical crown-lengthening procedure: A prospective study

    Directory of Open Access Journals (Sweden)

    Shobha K

    2010-01-01

    Full Text Available Background and Objectives: The purpose of this study was to evaluate the positional changes of the periodontal tissues, particularly the biological width, following surgical crown-lengthening in human subjects. Materials and Methods: A clinical trial study involving 15 patients was carried out for a period of 6 months. Sites were divided into 3 groups: treated (TT sites, adjacent (AD sites and nonadjacent (NAD sites. Free gingival margin [FGM], attachment level, pocket depth, bone level, biological width [BW] were recorded at baseline, 1, 3 and 6 months. Direct bone level after flap reflection was recorded before and after osseous resection at baseline only. Level of osseous crest was lowered based on BW, and supracrestal tooth structure needed using a combination of rotary and hand instruments. Statistical Analysis: Student t test and ANOVA were used. Results: Overall, apical displacement of FGM at TT, AD and NAD sites was statistically significant compared to baseline. The apical displacement of FGM at TT site was more when compared to that at AD and NAD sites at 3 and 6 months. The BW at the TT site was smaller at 1, 3 and 6 months compared to that at baseline. However, at all sites, BW was reestablished to the baseline value at the end of 6 months. Interpretation and Conclusion: The BW at TT sites was reestablished to its original vertical dimension by 6 months. In addition, a consistent 2-mm gain of coronal tooth structure was observed at the 1, 3 and 6-month examinations.

  8. Comparison of different methods involved in the planning of clinical crown lengthening surgery.

    Science.gov (United States)

    Zanatta, Fabricio Batistin; Giacomelli, Bruno Rodrigues; Dotto, Patricia Pasquali; Fontanella, Vânia Regina Camargo; Rosing, Cassiano Kuchenbecker

    2010-01-01

    There is little material in the literature that compares biological width measurements in periapical and bite-wings radiographs with clinical measurements. The purpose of this study was to compare measurements of biological width taken by three different methods which are frequently used for planning periodontal surgery - periapical radiograph, bite-wing radiograph and transperiodontal probing - with the trans-surgical measurements. Thirty-four sites from twenty-one subjects were analyzed. The intra-class correlation coefficients between measurements obtained trans-surgically (gold standard) and those obtained by transperiodontal probing, periapical radiography and bite-wing radiography were determined. Average measurements were compared using the Wilcoxon test at a significance level of 0.05. Also, the frequency distribution of differences between test measurements and the gold standard was calculated. The results showed that transperiodontal probing (mean 2.05 mm) was the most accurate measurement, as compared to the gold standard (mean 1.97 mm), with no statistically significant difference observed. On the other hand, periapical and bite-wing radiographic mean values (1.56 mm and 1.72 mm, respectively) were smaller than the gold standard, with statistically significant differences (p crown lengthening surgery should, preferably, include transperiodontal probing.

  9. First-trimester screening in pregnancies conceived by assisted reproductive technology: significance of gestational dating by oocyte retrieval or sonographic measurement of crown-rump length

    DEFF Research Database (Denmark)

    Gjerris, A.C.; Loft, A.; Pinborg, A.;

    2008-01-01

    OBJECTIVES: To evaluate, in pregnancies conceived by assisted reproductive technology, whether determination of gestational age (GA) by date of oocyte aspiration (DOA) or crown-rump length (CRL) at first-trimester screening influences the distribution of serum and sonographic markers or the...... performance of first-trimester screening for chromosomal abnormalities. METHODS: GA was calculated using either DOA or CRL at blood sampling and nuchal translucency thickness (NT) measurement in 729 singleton pregnancies conceived by in-vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI......). Weight-corrected log multiples of the median (MoM) marker distributions specific for IVF pregnancy were established using multiple log regression and compared for DOA- and CRL-based GA calculation. RESULTS: GA determined by CRL was significantly larger, albeit slightly, than was GA determined by DOA...

  10. Lateral cane lengths affect yield components in 'Triple Crown' blackberry on rotating cross-arm trellis and cane training system

    Science.gov (United States)

    Three primocanes of mature ‘Triple Crown’ blackberry plants were trained on the rotating cross-arm trellis (RCA) trellis. By the end of the summer, as many as 30 lateral canes with lengths greater than 3.5 m had developed on three primocanes that had been bent at a 0.50-m height and allowed to exte...

  11. Surgical crown lengthening for function and esthetics.

    Science.gov (United States)

    Allen, E P

    1993-04-01

    Clinical crown lengthening is a useful procedure to provide tooth length for proper restoration of a tooth without compromising the periodontium or the retentive qualities of the restoration. It is also useful for enhancing maxillary anterior esthetics. Crown lengthening may be as simple as a limited removal of soft tissue or as complex as orthodontic extrusion followed by flap with osseous surgery on a tooth requiring endodontic therapy. Total treatment could thus involve endodontic, orthodontic, periodontic, and restorative procedures. Careful evaluation, case selection, treatment planning, and surgical treatment following the principles outlined in this article can achieve results that meet the functional and esthetic challenges of current dental practice.

  12. WITHDRAWN: Clinical fitting of CAD/CAM zirconia single crowns generated from digital intraoral impressions based on active wavefront sampling.

    Science.gov (United States)

    Scotti, Roberto; Cardelli, Paolo; Baldissara, Paolo; Monaco, Carlo

    2011-10-17

    OBJECTIVES: The aim of this clinical trial was to test the accuracy of single all-ceramic zirconia crowns resulting from digital intraoral impressions with active wavefront sampling technology by measuring the marginal and internal fits of the crowns. MATERIALS AND METHODS: Thirty-seven teeth (24 anterior and 13 posterior) in fifteen patients were restored with single zirconia-ceramic crowns (Lava/Lava Ceram; 3M ESPE) generated from a digital intraoral scanner (Lava Chairside Oral Scanner; 3M ESPE). Before definitive insertion, silicone replicas were produced for all 37 crowns. The sample was cut in four sections; each section was evaluated in four points: marginal gap, mid-axial wall, axio-occlusal edge and centro-occlusal. A total of 592 measurements (148 for each evaluation point) was examined using stereomicroscopy with a magnification of 50×. The Mann-Whitney U test was used to evaluate whether there were differences between anterior and posterior values (alpha=0.05). RESULTS: The mean values for each point were: 48.65μm (SD 29.45μm) for the marginal gap, 112.25μm (SD 55.54μm) at the mid-axial wall, 137.81μm (SD 71.31μm) at the axio-occlusal edge of the abutments, and 157.25μm (SD 75.51μm) at the centro-occlusal location. No statistical differences were found between the anterior and posterior group for each point (p-values: P1=0.39; P2=0.38; P3=0.07; P4=0.30). CONCLUSIONS: The marginal and internal fitting values obtained were within literature agreed as clinically acceptable for both anterior and posterior teeth. CLINICAL RELEVANCE: Single crown restorations obtained using digital intraoral impressions based on active wavefront sampling technology presented enough accuracy to be used as an alternative to the conventional impression techniques. PMID:22027653

  13. Clinical evaluation of the fiber post and direct composite resin restoration for fixed single crowns on endodontically treated teeth

    Science.gov (United States)

    Murali Mohan, S.; Mahesh Gowda, E.; Shashidhar, M.P.

    2015-01-01

    Background The restoration of an endodontically treated fractured tooth has been a challenge for restorative dentists for decades. The performance of fiber posts when used in conjunction with direct composite resin restorations have been largely unreported. This study was conducted with the aim of evaluating the survival rate of endodontically treated teeth restored with adhesive bonded fiber reinforced resin posts and direct composite core with additional crown coverage. Methods Sixty patients who required endodontic treatment with post core crown were selected from outpatient department of Air Force Institute of Dental Sciences, Bangalore. Sixty-four teeth were endodontically treated and restored with fiber post and direct resin composite core restoration. Patients were evaluated immediately after restoration and reevaluated at the end of first, second and third months. After 3 months of clinical evaluation, if teeth were asymptomatic they were restored with complete coverage porcelain fused to metal restorations and evaluated immediately, and again reevaluated at the end of first, third, and sixth months. Results After 3 months of clinical evaluation, only two teeth exhibited periapical lesion with clinical symptoms and three teeth without any clinical symptoms. Five teeth exhibited slight marginal staining, three teeth showed partial loss of restoration, and two teeth exhibited complete loss of restoration with the fracture of the post. At the end of sixth month after restoration with full coverage crown, two teeth had dislodged restoration due to fracture of post and two teeth exhibited displacement of the post. Conclusion Fiber posts are the best alternative for restoration of fractured endodontically treated teeth. Fiber posts and direct composite resin core materials are strongly recommended for restoration of endodontically treated mutilated teeth among the dental establishments of Armed Forces. PMID:26288494

  14. Fabrication of a metal-ceramic crown to fit an existing partial removable dental prosthesis using ceramic pressed to metal technique: a clinical report

    OpenAIRE

    Seo, Jae-Min; Ahn, Seung-Geun

    2014-01-01

    Fabricating a crown to retrofit an existing abutment tooth for a partial removable dental prosthesis (PRDP) is one of the most time-consuming and labor-intensive clinical procedures. In particular, when the patient is concerned with esthetic aspects of restoration, the task of fabricating becomes more daunting. Many techniques for the fabrication of all-metallic or metal-ceramic crowns have been discussed in the literature. This article was aimed to describe a simple fabrication method in whi...

  15. Effectiveness of Crown Preparation Assessment Software As an Educational Tool in Simulation Clinic: A Pilot Study.

    Science.gov (United States)

    Tiu, Janine; Cheng, Enxin; Hung, Tzu-Chiao; Yu, Chuan-Chia; Lin, Tony; Schwass, Don; Al-Amleh, Basil

    2016-08-01

    The aim of this pilot study was to evaluate the feasibility of a new tooth preparation assessment software, Preppr, as an educational tool for dental students in achieving optimal parameters for a crown preparation. In February 2015, 30 dental students in their fourth year in a five-year undergraduate dental curriculum in New Zealand were randomly selected from a pool of volunteers (N=40) out of the total class of 85. The participants were placed into one of three groups of ten students each: Group A, the control group, received only written and pictorial instructions; Group B received tutor evaluation and feedback; and Group C performed self-directed learning with the aid of Preppr. Each student was asked to prepare an all-ceramic crown on the lower first molar typodont within three hours and to repeat the exercise three times over the next four weeks. The exercise stipulated a 1 mm finish line dimension and total convergence angles (TOC) between 10 and 20 degrees. Fulfillment of these parameters was taken as an acceptable preparation. The results showed that Group C had the highest percentage of students who achieved minimum finish line dimensions and acceptable TOC angles. Those students also achieved the stipulated requirements earlier than the other groups. This study's findings provide promising data on the feasibility of using Preppr as a self-directed educational tool for students training to prepare dental crowns. PMID:27480712

  16. A practice-based clinical evaluation of the survival and success of metal-ceramic and zirconia molar crowns: 5-year results.

    Science.gov (United States)

    Rinke, S; Kramer, K; Bürgers, R; Roediger, M

    2016-02-01

    This practice-based study evaluates the survival and success of conventionally luted metal-ceramic and zirconia molar crowns fabricated by using a prolonged cooling period for the veneering porcelain. Fifty-three patients were treated from 07/2008 to 07/2009 with either metal-ceramic crowns (MCC) or zirconia crowns (ZC). Forty-five patients (26 female) with 91 restorations (obser-vational period: 64.0 ± 4.8 months) participated in a clinical follow-up examination and were included in the study. Estimated cumulative survival (ECSv), success (ECSc) and veneering ceramic success (ECVCSc) were calculated (Kaplan-Meier) and analysed by the crown fabrication technique and the position of the restoration (Cox regression model) (P zirconia molar crowns demonstrated a 5-year ECSv, ECSc and ECVCSc comparable to MCCs. Irrespective of the fabrication technique, crowns on terminal abutments bear a significantly increased risk for VCFs. Clinical investigations with an increased number of restorations are needed.

  17. Evaluation of Clinical Effect of Procera Allceram Crown%高纯铝瓷Procera ALLceram全冠修复的临床效果

    Institute of Scientific and Technical Information of China (English)

    杨旭; 任英华; 邓燕; 郭照中; 郑蓉; 艾红军

    2011-01-01

    Objective To olserve and evaluate the clinical effect of procera allceram crown. Methods 81 procera allceram crowns were fabricated for 58 patients who needed crown therapy for pulpitis, periapical periodontitis, dental trauma, abnormal tooth and dental stain. The crowns were examined with a modified USPHS criteria 3~24 months after dental repairation. Results 2 crowns had undergone a fracture of the veneering porcelain. Color matches to adjacent for 3 crowns were graded B. 93.8% of the remaining crowns in color match, marginal discoloration, marginal integrity, secondary dental caries, visible cracks were graded A. Conclusion A satisfying repair effect could be obtained by using procera allceram crown.%目的 观察和评估高纯铝瓷Procera ALLceram全冠修复体临床应用效果.方法 对因牙髓炎、根尖周炎、外伤、牙畸形、牙变色等各种原因造成需行牙冠修复的58例门诊患者,采用81个高纯铝瓷Procera ALLceram全冠修复体,修复3~24个月后按照美国公共健康协会的修正标准(USPHS)进行评估.结果 81件修复体,2件出现饰面瓷崩裂,3件修复体颜色为B级,余93.8%修复体在颜色、边缘着色、边缘密合度、继发龋及修复体碎裂等各项检查指标中均为A级.结论 高纯铝瓷Procera ALLceram全冠修复体具有良好的修复效果.

  18. CAD/CAM ZIRCONIA VS. SLIP-CAST GLASS-INFILTRATED ALUMINA/ZIRCONIA ALL-CERAMIC CROWNS: 2-YEAR RESULTS OF A RANDOMIZED CONTROLLED CLINICAL TRIAL

    OpenAIRE

    Murat Cavit Çehreli; Ali Murat Kökat; Kivanç Akça

    2009-01-01

    The aim of this randomized controlled clinical trial was to compare the early clinical outcome of slip-cast glass-infiltrated Alumina/Zirconia and CAD/CAM Zirconia all-ceramic crowns. A total of 30 InCeram® Zirconia and Cercon® Zirconia crowns were fabricated and cemented with a glass ionomer cement in 20 patients. At baseline, 6-month, 1-year, and 2-year recall appointments, Californian Dental Association (CDA) quality evaluation system was used to evaluate the prosthetic replacements, and p...

  19. Effects of dry period length on clinical mastitis and other major clinical health disorders

    DEFF Research Database (Denmark)

    Enevoldsen, Carsten; Sørensen, J.T.

    1992-01-01

    Four, 7-, and 10-wk dry periods were randomly assigned to 366 dairy cows in eight herds. A multiple polytomous logistic regression analysis was conducted with the objective to reveal possible important effects of the dry period on the risk of contracting major clinical health disorders. Several...... calving intervals, the risk of occurrence of complications at calving decreased with the length of the dry period. This relation was reversed at longer calving intervals. Dry period lengths of approximately 7 wk appear to be associated with the lowest risk of clinical health disorders, but other factors...

  20. 全瓷冠与金属烤瓷冠的临床应用分析%Clinical application on all ceramic crowns and metal ceramic crowns

    Institute of Scientific and Technical Information of China (English)

    代伟; 刘阳

    2015-01-01

    Objective:To investigate the aesthetic effect and the change of periodontal tissue in the restoration of all ceramic crowns and metal ceramic crowns.Methods:108 cases of dental restoration restoration on a total of 168 teeth were selected,they were divided into two groups,with 84 teeth in each group,patients in the observation group were treated with zirconia all ceramic dental restoration,while in the control with Ni Cr alloy porcelain dental restoration.Results:After 1 years,the observation group did not appear cervical margin black line,while 39 teeth in the control group had appear black or marginal discoloration problem. Conclusion:Compared with metal ceramic crowns,all ceramic crowns can reduce the damage to the periodontal tissues,and the appearance and color are excellent,with higher simulation,however,in the crown and bridge it is not as good as the metal porcelain teeth.%目的:探讨全瓷冠与金属烤瓷冠修复的美学效果及牙周组织变化.方法:收治牙齿修复患者 108 例,共计168颗牙,随机分为两组,各84颗,观察组进行二氧化锆全瓷牙修复,对照组进行镍铬合金烤瓷牙修复.结果:1年后,观察组未出现颈缘黑线情况,对照组有39颗出现颈缘发黑、变色问题.结论:全瓷冠相较于金属烤瓷冠用于牙体修复可减少对牙周组织的损伤,而且外观与色泽较为优良,有更高的仿真性,然而在冠桥折断方面不如金属烤瓷牙.

  1. Crown lengthening: the periodontal-restorative connection.

    Science.gov (United States)

    Becker, W; Ochsenbein, C; Becker, B E

    1998-03-01

    Crown lengthening procedures are based on biologic principles that can be determinants for successful treatment. These procedures are fixed on an understanding of the biologic width. A few of the indications for crown lengthening are caries beneath the gingival margin, fractured teeth with insufficient clinical crown exposure, and teeth with excessive occlusal or incisal wear. This article describes flap designs, the use of a new bur probe for precise measurement of clinical crown exposure, and suturing methods for flap stabilization. Clinical documentation of patients with various clinical situations requiring crown lengthening is presented.

  2. CAD/CAM Zirconia vs. slip-cast glass-infiltrated Alumina/Zirconia all-ceramic crowns: 2-year results of a randomized controlled clinical trial

    Directory of Open Access Journals (Sweden)

    Murat Cavit Çehreli

    2009-02-01

    Full Text Available The aim of this randomized controlled clinical trial was to compare the early clinical outcome of slip-cast glass-infiltrated Alumina/Zirconia and CAD/CAM Zirconia all-ceramic crowns. A total of 30 InCeram® Zirconia and Cercon® Zirconia crowns were fabricated and cemented with a glass ionomer cement in 20 patients. At baseline, 6-month, 1-year, and 2-year recall appointments, Californian Dental Association (CDA quality evaluation system was used to evaluate the prosthetic replacements, and plaque and gingival index scores were used to explore the periodontal outcome of the treatments. No clinical sign of marginal discoloration, persistent pain and secondary caries was detected in any of the restorations. All InCeram® Zirconia crowns survived during the 2-year period, although one nonvital tooth experienced root fracture coupled with the fracture of the veneering porcelain of the restoration. One Cercon® Zirconia restoration fractured and was replaced. According to the CDA criteria, marginal integrity was rated excellent for InCeram® Zirconia (73% and Cercon® Zirconia (80% restorations, respectively. Slight color mismatch rate was higher for InCeram® Zirconia restorations (66% than Cercon® Zirconia (26% restorations. Plaque and gingival index scores were mostly zero and almost constant over time. Time-dependent changes in plaque and gingival index scores within and between groups were statistically similar (p>0.05. This clinical study demonstrates that single-tooth InCeram® Zirconia and Cercon® Zirconia crowns have comparable early clinical outcome, both seem as acceptable treatment modalities, and most importantly, all-ceramic alumina crowns strengthened by 25% zirconia can sufficiently withstand functional load in the posterior zone.

  3. CAD/CAM ZIRCONIA VS. SLIP-CAST GLASS-INFILTRATED ALUMINA/ZIRCONIA ALL-CERAMIC CROWNS: 2-YEAR RESULTS OF A RANDOMIZED CONTROLLED CLINICAL TRIAL

    Science.gov (United States)

    Çehreli, Murat Cavit; Kökat, Ali Murat; Akça, Kivanç

    2009-01-01

    The aim of this randomized controlled clinical trial was to compare the early clinical outcome of slip-cast glass-infiltrated Alumina/Zirconia and CAD/CAM Zirconia all-ceramic crowns. A total of 30 InCeram® Zirconia and Cercon® Zirconia crowns were fabricated and cemented with a glass ionomer cement in 20 patients. At baseline, 6-month, 1-year, and 2-year recall appointments, Californian Dental Association (CDA) quality evaluation system was used to evaluate the prosthetic replacements, and plaque and gingival index scores were used to explore the periodontal outcome of the treatments. No clinical sign of marginal discoloration, persistent pain and secondary caries was detected in any of the restorations. All InCeram® Zirconia crowns survived during the 2-year period, although one nonvital tooth experienced root fracture coupled with the fracture of the veneering porcelain of the restoration. One Cercon® Zirconia restoration fractured and was replaced. According to the CDA criteria, marginal integrity was rated excellent for InCeram® Zirconia (73%) and Cercon® Zirconia (80%) restorations, respectively. Slight color mismatch rate was higher for InCeram® Zirconia restorations (66%) than Cercon® Zirconia (26%) restorations. Plaque and gingival index scores were mostly zero and almost constant over time. Time-dependent changes in plaque and gingival index scores within and between groups were statistically similar (p>0.05). This clinical study demonstrates that single-tooth InCeram® Zirconia and Cercon® Zirconia crowns have comparable early clinical outcome, both seem as acceptable treatment modalities, and most importantly, all-ceramic alumina crowns strengthened by 25% zirconia can sufficiently withstand functional load in the posterior zone. PMID:19148406

  4. Clinical effects of modified surgical crown lengthening%改良牙冠延长术临床疗效的观察

    Institute of Scientific and Technical Information of China (English)

    章彦彦; 陈才展; 邓燕; 杨旭; 黄继洪; 高丽萍

    2013-01-01

    AIM:To observe the clinical effects of modified crown lengthening surgery.METHODS:Modified crown lengthening was performed on 31 teeth with crown defects involved more than 3 mm subgingivally.Plaque index (PLI),bleeding index (BI),probing depth (PD) and tooth mobility (TM) were measured before and 1,3,9 and 15 months after operation at follow-up.RESULTS:PLI,BI,PD and TM were significantly decreased at 1,3,9and 15 months after modified crown lengthening (P < 0.05).Gingival health and gingival margin coordination were improved,prosthetic replacements were stable in all patienrs.CONCLUSION:Modified surgical crown lengthening is an effective surgical method for conventional crown lengthening.%目的:观察改良牙冠延长术的临床疗效.方法:对31例患者的31个牙体缺损延伸至龈下3.0 mm以上患牙行改良牙冠延长术,术后1、3、9、15个月随访,比较患牙术前后的菌斑指数(PLI)、出血指数(BI)、牙周探诊深度(PD)和松动度(TM).结果:31个患牙术后1,3,9,15个月的PD、BI、PLI、TM较术前改善明显(均为P<0.05);术后无松动、牙龈健康、龈缘协调;修复体稳定;患者自诉功能良好,疗效满意.结论:改良牙冠延长术可作为常规牙冠延长术不足的一种弥补.

  5. Clinical Observations on Crown Lengthening Surgery with Piezosurgery.%超声骨刀在牙冠延长术中的应用效果观察

    Institute of Scientific and Technical Information of China (English)

    杨萍; 高永波; 李绍岳; 骆伟燕; 周利文; 韩琼

    2011-01-01

    目的:评价超声骨刀在牙冠延长术中的应用效果.方法:应用超声骨刀对20例患者的30颗患牙作牙冠延长术,检测术前、术后1周、术后4周患牙龈沟出血指数、缺损最低处探诊深度.结果:30颗患牙在观察期内均获得良好效果,患牙达到桩冠修复的条件.结论:超声骨刀应用于牙冠延长术可获得良好的疗效.%Objective: To evaluate the clinical effects of crown lengthening surgery by piezosurgery.Methods:Thirty teeth from twenty patients underwent crown lengthening surgery by piezosurgery.The sulcus bleeding index (SBI) and maximal defect probing depth (PD) were measured before the surgery as well as 7 days and 28 days later.Results: The clinical effects of surgery were good.The thirty teeth had achieved the indications for post crown.Conclusion: Piezosurgery is an ideal therapeutic method for crown lengthening surgery.

  6. Removal of failed crown and bridge.

    Science.gov (United States)

    Sharma, Ashu; Rahul, G R; Poduval, Soorya T; Shetty, Karunakar

    2012-07-01

    Crown and bridge have life span of many years but they fail for a number of reasons. Over the years, many devices have been designed to remove crowns and bridges from abutment teeth. While the removal of temporary crowns and bridges is usually very straightforward, the removal of a definitive cast crown with unknown cement is more challenging. Removal is often by destructive means. There are a number of circumstances, however, in which conservative disassembly would aid the practitioner in completing restorative/endodontic procedures. There are different mechanisms available to remove a failed crown or bridge. But there is no information published about the classification of available systems for crown and bridge removal. So it is logical to classify these systems into different groups which can help a clinician in choosing a particular type of system depending upon the clinical situation. The aim of this article is to provide a classification for various crown and bridge removal systems; describe how a number of systems work; and when and why they might be used. A PubMed search of English literature was conducted up to January 2010 using the terms: Crown and bridge removal, Crown and bridge disassembly, Crown and bridge failure. Additionally, the bibliographies of 3 previous reviews, their cross references as well as articles published in various journals like International Endodontic Journal, Journal of Endodontics and were manually searched. Key words:Crown and bridge removal, Crown and bridge disassembly, Crown and bridge failure. PMID:24558549

  7. Crowning corals

    Digital Repository Service at National Institute of Oceanography (India)

    Raghukumar, C.

    such as giant clams, sea cucumbers, sea anemones, sea urchins, sea fans, crown-of-thorns starfish and a variety of coloured fishes. Each of these animals have a special niche in this system. The three major types of reefs are the fringing reefs, barrier reefs...

  8. Clinical effect of crown lengthening surgery on the residual root and crown%牙冠延长术在残根残冠治疗中的疗效分析

    Institute of Scientific and Technical Information of China (English)

    方道文; 郑炜; 陈青蓝

    2012-01-01

    Objective To explore the clinical effect of treatment methods to restore the residual crown and root. Methods We collected 30 residual crown and roots teeth whose profile are located in the subgingival due to caries and tooth fracture. Then we randomly divided them into two groups, Gingival excision and surgical crown lengthening were applied respectively for repair of anterior gingival surgery treatment. Results The teeth sections were exposed well immediately. The gingival of the two groups had mild edema 1 week after operation , then improved obviously after 2 weeks. In the surgical crown lengthening group the gingival margin was in good shape after 6 weeks, and the gingival was return to normal after 6 months. The periodontal status improved obviously at each time point after operation. Some teeth sections of the gingival excision group were covered by the gingival after 6 weeks to 6 months. The periodontal conditions improved after 2 to 6 weeks,but the gingival sulcus bleeding index increased obviously after 6 monthes. Conclusion Compared to gingival excision , crown lengthening surgery is more advantageous to the residual crown and residual root preservation and restoration, but the choice of indication should be carefully considered.%目的 观察牙冠延长术在残根、残冠保留治疗中的临床效果.方法 收集因龋坏、牙折等所致牙齿断面位于龈下的残根、残冠30颗,随机分成两组,分别应用牙龈切除术及牙冠延长术进行修复前的牙龈外科处理.结果 所有患牙龈下断端在术后即刻均得以暴露.两组术后1周术区龈缘均轻度水肿,2周明显好转.冠延长术组术后6周龈缘外形良好,术后6月基本恢复正常,断端平齐龈缘或位于龈缘冠方;术后各时间点牙周状况均有明显改善.牙龈切除术组术后6周~6月部分患牙龈下断端被牙龈覆盖;术后2~6周牙周状况有所改善,但术后6月龈沟出血指数加重明显.结论 牙冠延长术较牙

  9. Porcelain fractures in implant borne fixed dental prostheses and single crowns A retrospective clinical study

    OpenAIRE

    Mikeli, Aikaterini

    2015-01-01

    Introduction: Porcelain fractures belong to the most frequent technical complications in implant borne fixed restorations. Aim of this retrospective clinical study was to determine the prevalence and extent of porcelain fractures and to detect possible risk indicators. Methods: The study was designed by the Department of Prosthetic Dentistry, Dental School, University Hospital Carl Gustav Carus of Technical University of Dresden (TUD). Only adult patients (age ≥ 18 years) having previous...

  10. UK National Clinical Guidelines in Paediatric Dentistry: stainless steel preformed crowns for primary molars.

    Science.gov (United States)

    Kindelan, S A; Day, P; Nichol, R; Willmott, N; Fayle, S A

    2008-11-01

    This revised Clinical Guideline in Paediatric Dentistry replaces the previously published sixth guideline (Fayle SA. Int J Paediatr Dent 1999; 9: 311-314). The process of guideline production began in 1994, resulting in first publication in 1997. Each guideline has been circulated widely for consultation to all UK consultants in paediatric dentistry, council members of the British Society of Paediatric Dentistry (BSPD), and to people of related specialities recognized to have expertise in the subject. The final version of this guideline is produced from a combination of this input and thorough review of the published literature. The intention is to encourage improvement in clinical practice and to stimulate research and clinical audit in areas where scientific evidence is inadequate. Evidence underlying recommendations is scored according to the SIGN classification and guidelines should be read in this context. Further details regarding the process of paediatric dentistry guideline production in the UK is described in the Int J Paediatr Dent 1997; 7: 267-268.

  11. Surface roughness of zirconia for full-contour crowns after clinically simulated grinding and polishing.

    Science.gov (United States)

    Hmaidouch, Rim; Müller, Wolf-Dieter; Lauer, Hans-Christoph; Weigl, Paul

    2014-12-01

    The aim of this study was to evaluate the effect of controlled intraoral grinding and polishing on the roughness of full-contour zirconia compared to classical veneered zirconia. Thirty bar-shaped zirconia specimens were fabricated and divided into two groups (n=15). Fifteen specimens (group 1) were glazed and 15 specimens (group 2) were veneered with feldspathic ceramic and then glazed. Prior to grinding, maximum roughness depth (Rmax) values were measured using a profilometer, 5 times per specimen. Simulated clinical grinding and polishing were performed on the specimens under water coolant for 15 s and 2 N pressure. For grinding, NTI diamonds burs with grain sizes of 20 µm, 10 µm, and 7.5 µm were used sequentially. The ground surfaces were polished using NTI kits with coarse, medium and fine polishers. After each step, Rmax values were determined. Differences between groups were examined using one-way analysis of variance (ANOVA). The roughness of group 1 was significantly lower than that of group 2. The roughness increased significantly after coarse grinding in both groups. The results after glazing were similar to those obtained after fine grinding for non-veneered zirconia. However, fine-ground veneered zirconia had significantly higher roughness than venerred, glazed zirconia. No significant difference was found between fine-polished and glazed zirconia, but after the fine polishing of veneered zirconia, the roughness was significantly higher than after glazing. It can be concluded that for full-contour zirconia, fewer defects and lower roughness values resulted after grinding and polishing compared to veneered zirconia. After polishing zirconia, lower roughness values were achieved compared to glazing; more interesting was that the grinding of glazed zirconia using the NTI three-step system could deliver smooth surfaces comparable to untreated glazed zirconia surfaces.

  12. Surface roughness of zirconia for full-contour crowns after clinically simulated grinding and polishing.

    Science.gov (United States)

    Hmaidouch, Rim; Müller, Wolf-Dieter; Lauer, Hans-Christoph; Weigl, Paul

    2014-12-01

    The aim of this study was to evaluate the effect of controlled intraoral grinding and polishing on the roughness of full-contour zirconia compared to classical veneered zirconia. Thirty bar-shaped zirconia specimens were fabricated and divided into two groups (n=15). Fifteen specimens (group 1) were glazed and 15 specimens (group 2) were veneered with feldspathic ceramic and then glazed. Prior to grinding, maximum roughness depth (Rmax) values were measured using a profilometer, 5 times per specimen. Simulated clinical grinding and polishing were performed on the specimens under water coolant for 15 s and 2 N pressure. For grinding, NTI diamonds burs with grain sizes of 20 µm, 10 µm, and 7.5 µm were used sequentially. The ground surfaces were polished using NTI kits with coarse, medium and fine polishers. After each step, Rmax values were determined. Differences between groups were examined using one-way analysis of variance (ANOVA). The roughness of group 1 was significantly lower than that of group 2. The roughness increased significantly after coarse grinding in both groups. The results after glazing were similar to those obtained after fine grinding for non-veneered zirconia. However, fine-ground veneered zirconia had significantly higher roughness than venerred, glazed zirconia. No significant difference was found between fine-polished and glazed zirconia, but after the fine polishing of veneered zirconia, the roughness was significantly higher than after glazing. It can be concluded that for full-contour zirconia, fewer defects and lower roughness values resulted after grinding and polishing compared to veneered zirconia. After polishing zirconia, lower roughness values were achieved compared to glazing; more interesting was that the grinding of glazed zirconia using the NTI three-step system could deliver smooth surfaces comparable to untreated glazed zirconia surfaces. PMID:25059249

  13. Surface roughness of zirconia for full-contour crowns after clinically simulated grinding and polishing

    Institute of Scientific and Technical Information of China (English)

    Rim Hmaidouch; Wolf-Dieter Mu ller; Hans-Christoph Lauer; Paul Weigl

    2014-01-01

    The aim of this study was to evaluate the effect of controlled intraoral grinding and polishing on the roughness of full-contour zirconia compared to classical veneered zirconia. Thirty bar-shaped zirconia specimens were fabricated and divided into two groups (n515). Fifteen specimens (group 1) were glazed and 15 specimens (group 2) were veneered with feldspathic ceramic and then glazed. Prior to grinding, maximum roughness depth (Rmax) values were measured using a profilometer, 5 times per specimen. Simulated clinical grinding and polishing were performed on the specimens under water coolant for 15 s and 2 N pressure. For grinding, NTI diamonds burs with grain sizes of 20 mm, 10 mm, and 7.5 mm were used sequentially. The ground surfaces were polished using NTI kits with coarse, medium and fine polishers. After each step, Rmax values were determined. Differences between groups were examined using one-way analysis of variance (ANOVA). The roughness of group 1 was significantly lower than that of group 2. The roughness increased significantly after coarse grinding in both groups. The results after glazing were similar to those obtained after fine grinding for non-veneered zirconia. However, fine-ground veneered zirconia had significantly higher roughness than venerred, glazed zirconia. No significant difference was found between fine-polished and glazed zirconia, but after the fine polishing of veneered zirconia, the roughness was significantly higher than after glazing. It can be concluded that for full-contour zirconia, fewer defects and lower roughness values resulted after grinding and polishing compared to veneered zirconia. After polishing zirconia, lower roughness values were achieved compared to glazing;more interesting was that the grinding of glazed zirconia using the NTI three-step system could deliver smooth surfaces comparable to untreated glazed zirconia surfaces.

  14. A technique for retrofitting a metal ceramic crown to an attachment-retained removable partial denture: a clinical report.

    Science.gov (United States)

    Uludag, Bulent; Gonuldas, Fehmi; Tokar, Emre; Sahin, Volkan

    2015-02-01

    In dental applications, precision attachments have been used to retain removable partial dentures (RPDs) for several decades. Various types of extracoronal attachments are commonly used in combination with fixed partial dentures and RPDs to achieve retention and stability. Fracture of the framework, fracture of the roots or teeth, and irretrievable decrease of retention are common reasons for a failed attachment-retained RPD. Another complication of metal ceramic crowns with precision attachment is decementation of the crowns. When fixed components of the attachment-retained RPD fail, the traditional treatment approach requires remaking both the fixed and removable components of the attachment-retained RPD. This technique describes retrofitting of a metal ceramic crown to a resilient attachment-retained RPD. PMID:25066428

  15. 前牙全瓷冠饰瓷崩裂断口形貌分析%Fractographic analysis of clinically failed anterior all ceramic crowns

    Institute of Scientific and Technical Information of China (English)

    杜倩; 周敏波; 张新平; 赵克

    2012-01-01

    Objective To identify the site of crack initiation and propagation path of clinically failed all ceramic crowns by fractographic analysis.Methods Three clinically failed anterior IPS Empress Ⅱ crowns and two anterior In-Ceram alumina crowns were retrieved.Fracture surfaces were examined using both optical stereo and scanning electron microscopy.Fractographic theory and fracture mechanics principles were applied to disclose the damage characteristics and fracture mode.Results All the crowns failed by cohesive failure within the veneer on the labial surface.Critical crack originated at the incisal contact area and propagated gingivally. Porosity was found withiu the veneer because of slurry preparation and the sintering of veneer powder.Conclusions Cohesive failure within the veneer is the main failure mode of all ceramic crown.Veneer becomes vulnerable when flaws are present. To reduce the chances of chipping,multi-point occlusal contacts are recommended,and layering and sintering technique of veneering layer should also be improved.%目的 通过断口形貌观察分析临床失效的前牙全瓷冠,分析疲劳损伤的起源和发展,以期为优化全瓷冠桥修复体的临床设计及修复工艺提供依据.方法 收集临床失效前牙二硅酸锂基瓷冠( IPS EmpressⅡ)3例,玻璃渗透氧化铝瓷冠(In-Ceram)2例,采用体视显微镜和扫描电子显微镜观察断裂面,分析特征形貌.结果 5例全瓷冠主要失效模式均为唇侧饰瓷内聚破坏,裂纹起源于切端咬合接触区,并由切端向龈端扩展,裂纹源附近饰瓷内部见较多气孔缺陷.结论 饰瓷内聚破坏是全瓷修复失效的重要原因;饰瓷内部易出现制作缺陷,成为双层瓷修复体的薄弱环节;改良饰瓷制作及烧结工艺,设计多点咬合接触将有助于减少饰瓷崩瓷.

  16. Observation for the Clinical Effect of Post-and-Core Crown` Prosthesis to Residual Root and Residual Crown of Quiquagenarian%桩核冠修复中老年残根、残冠的临床疗效观察

    Institute of Scientific and Technical Information of China (English)

    王素艳

    2014-01-01

    目的:观察应用玻璃纤维桩、树脂桩核冠修复中老年残根、残冠的临床疗效。方法:对204例中老年患者共计255颗残根、残冠,采用玻璃纤维桩、树脂桩核冠修复和利用。其中,67颗牙用作固定桥修复牙列缺损的基牙,38颗牙用作可摘局部义齿支架修复的基牙。结果:255颗残根、残冠桩核冠修复后经过1~2年的临床随访观察,245颗牙临床疗效可靠,修复体咀嚼功能能满足患者的要求,成功率为96.1%。结论:应用玻璃纤维桩和树脂构建的树脂桩核冠对中老年患者残根、残冠的修复和利用,能达到良好的修复效果,具有广泛的应用前景。%Objective:To observe the clinical effect of quinquagenarian,who constructed by glass fiber post and resin treating residual root and crown.Method:A total of 255 residual roots and crowns for 204 cases of quinquagenarian patients were treated and utilized in use of full crown and resin post and core crown constructed by glass fiber post and resin .Among 255 teeth above,67 were functioning as the abutment of fixed bridge repairing dentition defect.And 38 were as the abutment to remore the surpport of partical denture roots and resdual crowns in use of resin post and core crown. Result:255 residualroots and residual crowns treatmented of resin post and core crown.1-2 years of follow-up clinical observation later,the clinical curatire effect of 245 was relsable and restoration of chewing function could meet the requirements of patients,with the success rate of 96.1%.Conclusion:It is able to achieve favorable result to apply resin post-and-core built by glass fiber post and resin and full crown to restore and utilize the quinquagenarian with residual roots and readual crowns,enjoying a potential and bright prospect.

  17. 牙冠延长术用于前牙修复再治疗的疗效分析%Clinic effects of crown lengthening in the re-therapy for anterior teeth restoration

    Institute of Scientific and Technical Information of China (English)

    桂盠; 唐丽琴; 冯琛琛

    2014-01-01

    目的:评价牙冠延长术应用于前牙修复再治疗的疗效。方法:选择因前牙烤瓷修复后牙龈肿胀出血,要求重新修复治疗的患者45例(72个前牙)。基线检查后,拆除原有烤瓷冠,完善根管治疗及牙周基础治疗,然后行牙冠延长术。术后8周行永久性修复并进行牙周检查;术后8周、6个月、1、2年复诊,分别记录出血指数和探诊深度,并进行疗效分析。结果:术后各时间点牙周指数分别与术前相比,数值下降差异有统计学意义(P<0.05);各时间点牙周指数之间相比,差异无统计学意义(P>0.05)。术后6个月、1、2年有效率分别与术后8周相比无统计学差异(P>0.05),8周后各时间点有效率无统计学差异(P>0.05)。结论:牙冠延长术用于前牙修复再治疗疗效良好。%AIM:To evaluate the clinical effects of surgical crown lengthening in the re-treatment of anteri-or teeth restoration.METHODS:45 patients complaining of gum edema after anterior teeth restoration (72 teeth) were included.After baseline examination,the previous ceramic crowns were removed,root canal therapy and perio-dontal therapy were done as indicated.Then,surgical crown lengthening was performed.8 weeks after crown lengthe-ning,permanent restorations were made.Sulcus bleeding index (SBI)and probing depth (PD)were recorded at 8week,6month,1year and 2 year follow-up.RESULTS:Significantly lower values of SBI and PD were found at all time points post crown lengthening as compared with that of pre-surgery (P0.05 ).CONCLUSION:Surgical crown lengthening is an effective method for the re-therapy of anterior teeth restoration.

  18. 金属烤瓷冠修复技术的临床效果观察%Clinical effect observation of metal-ceramic crown remediation technique

    Institute of Scientific and Technical Information of China (English)

    崔秀萍

    2015-01-01

    Objective To explore the clinical effect of metal-ceramic crown remediation technique and sum up the op-timal remediation of varieties of metal-ceramic crown. Methods Clinical data of 120 patients who visited our depart-ment and agreed on metal-ceramic crown remediation technique from July 2012 to June 2013 were retrospectively ana-lyzed and studied.Based on different remediation material,they were divided into observation group and control group,60 cases in each group.In observation group,inner crown in gold alloy was adopted for dental rehabilitation,while in control group,nichrome was chosen.One year after remediation,clinical therapeutic effect,occurrence of complications,advantage and disadvantage of two methods between two groups was analyzed and compared respectively. Results The total clini-cal therapeutic effect in observation group was 96.67%,much higher than that in control group accounting for 81.67%, with statistical difference (P<0.05).In observation group,incidence of complications like gingivitis,swelling and aching of gum,gingival bleeding,gingival discoloration,bad breath,and full crown loose was remarkably lower than that in control group,with statistical difference(P<0.05). Conclusion In the technique of metal-ceramic crown remediation,inner crown in gold alloy and nichrome both obtain satisfying effects,but the effect in the former is better than that in latter.Inner crown in gold alloy,at advantages of small damage to periodontium,few complications such as gingivitis,swelling and aching of gum,gingival bleeding,gingival discoloration,bad breath,and full crown loose and so forth,and high aesthetic perception,is a relatively ideal remediation,which is worthy of adoption and expansion.%目的:探讨金属烤瓷冠修复技术临床效果,总结金属烤瓷冠的最佳修复方法。方法选取2012年7月~2013年6月在本院口腔科就诊并选择金属烤瓷冠修复技术的120例患者的临床资料进行回顾性分析研究,根据

  19. Crown lengthening: a surgical flap approach.

    Science.gov (United States)

    Lundergan, W; Hughes, W R

    1996-09-01

    In many instances it is not possible to place a restoration margin without encroaching on the periodontal attachment apparatus. A surgical crown-lengthening procedure can provide a good solution to this common clinical problem. This article discusses indication and contraindication for surgical crown-lengthening procedures and presents an appropriate surgical technique.

  20. Clinical therapeutic effect comparison between Sirona Cerec 3D all-ceramic crowns and porcelain fused to metal crown in anterior teeth restoration%Sirona Cerec3D全瓷冠与金属烤瓷冠修复前牙的临床对比

    Institute of Scientific and Technical Information of China (English)

    汤琼

    2012-01-01

    目的 评价Sirona Cerec 3D全瓷冠进行前牙修复的临床效果.方法 将81例(145颗前牙)患者进行随机分组,参照美国加利福尼亚牙科协会(CDA)评价标准,对使用1年的牙冠进行评价,并与同期治疗的金属烤瓷冠进行对比.结果 Sirona Cerec 3D全瓷冠修复组在边缘完整性、解剖外形、颜色和表面的成功率分别为97.5%、95%、100%、97.5%,而金属烤瓷冠对照组成功率为97.6%、92.6%、87.8%和95.1%.修复组在解剖外形和颜色方面明显优于对照组(P<0.05),且牙龈炎等副反应发生率小.结论Sirona Cerec 3D全瓷冠进行前牙修复效果良好,值得临床广泛推广.%Objective To evaluate the clinical therapeutic effect ofSirona Cerec 3D all-ceramic crowns in anterior teeth restoration.Methods 81 patients(145 anterior teeth) were divided randomly into two groups.The clinical evaluation criteria of CDA was performed 6 months to two years after wearing.And we compared the effects with porcelain fused to metal (PFM) crowns in the same period.Results On the integrity of crown margin,anatomical shape,color and surface,the succeed rate of all-ceramic crowns group were 97.5%,95%,100% and 97.5% respectively while PFM crowns group were 97.6%,92.6%,87.8% and 95.1% respectively.All-ceramic crowns group was better than PFM crowns group on the anatomical shape and color ( P < 0.05 ) and had less side effects.Conclusion Sirona Cerec 3D all-ceramic crowns has a good effect in anterior teeth restoration,worthy in expanded clinical use.

  1. 超声骨刀在牙冠延长术中的临床应用%Clinical application of the piezosurgery for surgical crown lengthening

    Institute of Scientific and Technical Information of China (English)

    高秀秋; 王冠楠; 张卓

    2012-01-01

    Surgical crown lengthening can reduce the position of the gingival margin, expose health tooth structure, lengthen the clinical crown and favor the denture repair or help to solve aesthetic problems. We conducted surgical corown lengthening operation by piezosurgery in 11 paitnets involving 36 teeth. Health gingiva, stable and coordinatie gingival margin were observed in all cases with all teeth in 6-month follow- up.%牙冠延长术是通过手术的方法,降低龈缘位置、暴露健康的牙齿结构,使临床牙冠加长,从而利于义齿的修复或解决美观问题的一种牙周外科手术.我科采用超声骨刀行牙冠延长术11 例,术后观察6 个月,患牙牙龈健康、稳定、龈缘协调.

  2. Marginal and Internal Fit of Conventional Metal-Ceramic and Lithium Disilicate CAD/CAM Crowns.

    Science.gov (United States)

    Nam, Se-Jin; Yoon, Mi-Jung; Kim, Won-Hee; Ryu, Gil-Ju; Bang, Min-Ki; Huh, Jung-Bo

    2015-01-01

    This study aimed to evaluate and compare the marginal and internal gap widths of lithium disilicate computer-aided design / computer-assisted manufacture (LDC) crowns and conventionally produced porcelain-fused-to-metal (PFM) crowns. A convenience sample of 21 patients treated with a single restoration was selected. PFM and LDC crowns were fabricated for each selected abutment tooth, following traditional crown preparation. Silicone replicas were produced, and internal gaps and marginal gaps were measured. Internal gaps were significantly larger for the axial and occlusal surfaces of LDC crowns than for those of PFM crowns (P .05). Both LDC crowns and PFM crowns showed clinically acceptable marginal fit. PMID:26340013

  3. 前牙残根冠延长术后纤维桩核冠修复的临床研究%Clinical research of fiber post-core crown restoration after crown lengthening for upper anterior teeth residual root

    Institute of Scientific and Technical Information of China (English)

    罗永宏; 尹丽媚; 李慧; 刘青; 冯建国

    2016-01-01

    Objective To investigate curative effect by fiber post-core crown restoration after crown lengthening for upper anterior teeth residual root. Methods A total of 20 upper anterior fractured, or decayed to subgingival 2~4 mm teeth were repaired by fiber post-core and all-ceramic crown restoration on subgingival fracture surface after crown lengthening. Results There were 12 patients (19 teeth) received successful operation, along with good postoperative condition and successful crown restoration. Shallow defect group (10 teeth) had higher instant satisfaction degree as (9.5±0.3) points than (9.3±0.3) points of deep defect group (9 teeth) (P>0.05). The difference of mean plaque index and periodontal pocket depth had no statistical significance between shallow defect group and deep defect group (P>0.05), while the difference of their mean bleeding index and gingival index had statistical significance (P0.05)。浅缺损组和深缺损组残根修复后的平均菌斑指数、牙周袋深度比较(P>0.05);平均出血指数、牙龈指数比较(P<0.05)。结论前牙残根冠冠延长术能暴露根面,纤维桩及瓷全冠后可以达到良好地修复效果。

  4. Clinic treatment experience on crown fracture of young permanent incisors%年轻恒前牙冠折后的临床治疗体会

    Institute of Scientific and Technical Information of China (English)

    陈敏

    2013-01-01

    Objective To summarize young permanent incisors with crown fracture in clinical methods,to explore the most beneficial development of young permanent teeth a good way.Methods 30 young crown fracture of permanent incisors trauma cases is based on the pulp exposure,pulp without lesions,X ray shows the root development was specific conditions such as different disposal methods,and followed up after treatment for analysis.Results The review 1 week after treatment,direct pulp capping group 2 patients,indirect pulp capping,there were 2 cases of pulpotomy group,1 patient had pain.After 6 months later,indirect pulp capping success in 9 cases,1 case of failure;direct pulp capping success in 4 cases,2 cases failed;pulpotomy success in 5 cases,1 case of failure;apical surgery group induced a successful 8 cases,failure in 1 case.Conclusion The traumatic crown fracture of young permanent teeth should be handled as soon as possible.Not exposed pulp of crown fracture of young permanent incisor using the indirect pulp capping;on the exposed pulp of the young crown fracture of permanent incisors of time under treatment,pulp status,and root development was to take direct pulp capping,pulpotomy,Apexification the different treatment methods,the periodic review after treatment is not missing,until observed for root development and timely completion of root canal treatment.%目的:通过总结年轻恒前牙冠折的临床治疗方法,探讨最有益于年轻恒前牙良好发育的方法.方法:对30颗年轻恒前牙外伤冠折病例根据牙髓是否暴露、牙髓有无病变、X线片显示的根尖发育情况等具体情况采取不同处置方法,治疗后进行随访观察并作分析研究.结果:治疗后1周复查,直接盖髓术组有2例、间接盖髓术组有2例、活髓切断术组有1例出现疼痛.术后6个月复查,间接盖髓术成功9例,失败1例;直接盖髓术成功4例,失败2例;活髓切断术成功5例,失败1例;根尖诱导术组成功8

  5. Orthodontic crown lengthening.

    Science.gov (United States)

    Hohlt, W F

    1992-01-01

    As comprehensive dentistry becomes more complex, procedures must be developed to save teeth once considered unsuitable for crown restoration due to inaccessible finishing lines. Orthodontic crown lengthening is less invasive than a flap procedure and does not result in crestal bone reduction. The crown lengthening procedure is a simple and time-saving remedy for a difficult restorative problem.

  6. Modeling Crown Biomass for Four Pine Species in China

    Directory of Open Access Journals (Sweden)

    Wen-Tao Zou

    2015-02-01

    Full Text Available To analyze the main variables affecting crown biomass, we measured crown biomass and a number of variables describing tree size, such as stem diameter at breast height (D, tree height (H, crown width (Cw and crown length (Cl, from 754 sample trees of four pine species in China, specifically, Pinus massoniana, P. yunnanensis, P. tabulaeformis and P. elliottii. In addition, we developed individual tree crown biomass equations and compatible branch and needle biomass equations based on one-, two- and multi-variable models using nonlinear mixed-effects modeling and error-in-variable simultaneous equations. The results showed that: (i crown biomass was strongly correlated to D and H, and the new combined variables (D4/H and (D2/H were suitable for modeling two- and multi-variable crown biomass equations, respectively; (ii the four species were ranked as P. yunnanensis, P. massoniana, P. elliottii and P. tabulaeformis from small to large based on estimates from crown biomass equations, and the crown biomass estimate of P. tabulaeformis was about 60% greater than that of P. yunnanensis; (iii the ratio of branch to crown biomass increased with increasing D, and the four species were ranked as P. elliottii, P. tabulaeformis, P. massoniana and P. yunnanensis from small to large by the proportion of the branch to crown biomass; (iv the mean prediction errors (MPE’s of the crown biomass equations for the four species were less than 10%, which could meet precision needs for biomass estimation.

  7. 前牙龈下残根改良牙冠延长术后纤维桩联合全瓷冠修复的临床疗效评估%Evaluation of the clinical ef ect of fiber post combined with al ceramic crown after modified crown lengthening on subgingival residual root

    Institute of Scientific and Technical Information of China (English)

    陈燕芳; 班建东; 李军科; 孙红蕾; 梁建华; 吴晓宇

    2015-01-01

    目的:评价前牙龈下残根改良牙冠延长术后纤维桩联合全瓷冠修复的应用效果。方法:选择24例33颗上前牙因外伤、重度龋坏等造成只剩龈下残根的患者,行完善的根管治疗后,采用改良牙冠延长术延长临床牙冠长度后再应用纤维桩系统进行桩核及全瓷冠修复。通过临床检查和 x 线检查,评估纤维桩联合全瓷冠修复的临床应用效果。结果:随访12个月,24例患者的基牙无松动,未发生根折,纤维桩树脂核桩冠完好,无松动,无脱落,牙龈组织健康,牙槽骨无吸收,骨硬板连续一致。结论:对于因外伤、重度龋坏等造成只剩龈下残根的病例,采用改良牙冠延长术后纤维桩核联合全瓷冠进行桩冠修复有较好的治疗效果。%Objective:To evaluate the clinical ef ect of fiber post combined with al ceramic crown in the subgingival residual root of anterior teeth after modified crown lengthening sur-gery.Methods:24 patients whose maxil ary anterior teeth were fractured under gingiva because of trauma or odontonecrosis were repaired.After completely root canal therapy,the teeth were treated by modified crown lengthening surgery to increase the height of crown.Then,the teeth were treated with fiber post system and al ceramic crown.Periodontal condition,radiographic signs and pros-thodontic results were recorded.Results:According to the 12 months’clinical observation,the restoration was stable,the posts and roots had no movement or fracture,and the periodontal tissue was healthy.Conclusion:The fiber post system combined with al ceramic crown after modified crown lengthening are ef ective to treat the subgingival residual roots .

  8. Paediatric renal length measurements from ultrasound and DMSA scans: does clinical practice reflect theoretical normal values?

    International Nuclear Information System (INIS)

    Full text: Renal length measurement is a routine part of ultrasound examination in children and those results are plotted on a normogram style graph, so that each child's results are compared to a normal range (mean ± 2 S.D.). Renal length measurements from the posterior oblique views of dimercaptosuccinic acid (DMSA) scans in our department have not always correlated well with the ultrasound measurements on the same patients. Renal lengths from the DMSA scans of 120 patients with apparently normal kidneys were recorded and used to generate a normogram of renal length at different ages (0.5-7 years). This DMSA normogram was compared to the ultrasound (US) normogram used in the Paediatric Radiology Department, and it showed slight differences in renal lengths (3-8 mm), but that the US normogram had smaller coefficients of variation (US = 6.6%, NM 8.3%), implying a 'tighter' normal range. 39 of these patients had DMSA and ultrasound measurements of renal length within 3 months, and these were studied first by calculating the mean and CV values for different age groups, and then by plotting individual renal lengths on the appropriate normograms. The measured data produced much greater variability in the ultrasound measurements than the DTPA measurements, and the individual points produced 4/78 (5.1%) abnormal results for DMSA, but 21/78 (26.9%) abnormal results for ultrasound. Thus, in routine clinical use, using patients with apparently normal kidneys, ultrasound was unable to match the 'normal range' set by their current normogram, but the nuclear medicine showed 5.1% of values outside the normal (DMSA) range, which was completely appropriate for a range of ± 2 standard deviations

  9. 插销固位一体式金属桩部分冠修复磨牙的临床观察%Clinical observation of molar restoration by bolt fastening integrated metal pile partial crown

    Institute of Scientific and Technical Information of China (English)

    杨勃; 李少萍; 刘名; 梁瑞玲; 刘长虹

    2013-01-01

    Objective To evaluate the clinical effect of molar restoration with short clinical crowns and tooth defect by bolt pile retaining integrated metal pile partial crown.Methods Thiry-eight molars with short clinical crown,tooth defeet,intermaxillary insufficient clearance were repaired by bolt fastening integrated metal pile partial crown.The crowns were examined immediately,1 years,2 years,3 years after the restoration,and the tooth integrity,secondary caries,crown integrity,crown retention,marginal fit and adjacent relation were evaluated.Results Compare the restorations effect of 38 teeth in immediately,1 years,2 years and 3 years after restoration,bolt fastening integrated metal pile partial crown always had excellent retention force,marginal fit,tooth integrity and crown integrity,no secondary caries,and 2 cases of mild food impaction with a ratio of 5.3%.Conclusion The restoration effect of molars with short clinical crowns and tooth defect by bolt fastening integrated metal pile partial crown is excellent and has some practical value in clinical practice.%目的 评价插销固位一体式金属桩部分冠修复牙冠短伴牙体缺损磨牙的临床效果.方法 采用插销固位一体式金属桩部分冠,修复38颗临床牙冠短伴牙体缺损、颌间修复间隙不足的磨牙.修复后即刻、1年、2年、3年进行检查,从牙齿完整性、牙体有无继发龋、修复体完整性、修复体固位、修复体边缘适合性及修复体的邻接关系等进行评价.结果 38颗患牙修复后即刻、1年、2年及3年检查显示,插销固位一体式金属桩部分冠固位良好,牙体及修复体的完整性好,边缘适合性好,没有出现继发龋;有2颗出现轻度食物嵌塞,占5.3%.各项评价指标在修复后即刻、1年、2年、3年的差异均无统计学意义(P>0.05).结论 采用插销固位一体式金属桩部分冠修复临床牙冠短伴牙体缺损的磨牙,修复效果好,在临床上有一定的实用价值.

  10. Clinical application of temporary crown and cement materials: physical properties and biological safety%临时冠材料及黏结材料的临床应用:物理性能与生物安全性

    Institute of Scientific and Technical Information of China (English)

    聂二民; 姜瑞; 张春元; 曾尽娣; 谈济州

    2015-01-01

    背景:临时冠在临床应用较为广泛,临时冠及其黏结材料随着材料科学的发展不断更新,其临床应用、物理学性能及生物安全性方面也越来越优越.目的:综述临时冠及其黏结材料的临床应用现状、物理性能及生物安全性.方法:以"temporary crown,provisional crown,temporary restoration,provisional restoration,interim restoration"为英文检索词,应用计算机检索PubMed数据库中2004年1月至2014年12月发表的相关文章.纳入与临时冠及其黏结材料相关的研究文献,排除重复性研究.结果与结论:通过临床评价和实验研究得出,临时冠材料自身聚合收缩、聚合产热、单体释放等物理特性和细胞毒性、对软组织的刺激性等生物安全性方面是临床要克服的关键问题.临时冠材料和黏结材料在临床上应用广泛,随着新材料筛选和新制作方法的出现其具有巨大的应用前景和较高的临床价值,但在其实验室研究和临床应用的探索过程中,还有许多亟待解决和深入探究的问题.%BACKGROUND:Temporary crown has been used widely in clinic. The physical properties and biological safety of temporary crown and cement materials are more superior along with the development of material science. OBJECTIVE:To summarize clinical application, physical properties and biological safety of the temporary crown and cement materials. METHODS:PubMed database was searched by the key words of "temporary crown, provisional crown, temporary restoration, provisional restoration, interim restoration" in English to retrieve relevant articles published from January 2004 to December 2014. Literatures addressing the temporary crown and cement materials were included, and the repetitive researches were excluded. RESULTS AND CONCLUSION:Through the clinical evaluation and experimental study, the physical properties (polymerization shrinkage, polymerization heat production, polymerization monomer release) and

  11. Clinical common problems after restoration with telescopic crown-retained removable partial dentures%圆锥形套筒冠义齿修复后常见临床问题

    Institute of Scientific and Technical Information of China (English)

    吴琼; 胡伟平

    2015-01-01

    背景:圆锥形套筒冠义齿具有能够自行摘戴、清洁方便、固定义齿异物感小、功能恢复良好等优点,所以近年来应用广泛,但随之也出现了一些问题。目的:综述分析圆锥形套筒冠义齿修复的常见问题并提出对策。方法:应用计算机检索1980至2013年中国知网及PubMed数据库,中文检索词为“圆锥形套筒冠,基牙,临床观察”,英文检索词为“Cone sleeve crown,abutment,Clinical observation”,并且利用主题词补充扩展,广泛查阅近年来有关套筒冠的文献,限定文献语言为英语及中文。结果与结论:圆锥形套筒冠义齿作为修复牙周病伴发牙列缺损的较为理想修复方式,总体来说效果良好,但维持长期稳定的临床效果是套筒冠修复技术面临的主要难题。近年来学者也通过多种方法提高其长期稳定性,例如改变内冠材料效果最为突出,但这些方法在实际临床应用中的远期效果还需要长期观察。圆锥形套筒冠义齿修复后出现的基牙折裂、内冠脱落、基托折裂、牙周问题、固位力降低等为常见症状,通过修理一般不影响套筒冠义齿的继续使用。%BACKGROUND:Telescopic crown-retained removable partial dentures are characterized as pick to wear voluntarily, convenient to clean, smal foreign body sensation of the fixed denture, and good functional recovery, and have been widely used in recent years. However, there are also some problems existing. OBJECTIVE:To review the common problems of the telescopic crown-retained removable partial dentures and to raise the countermeasures. METHODS: A computer-based search of CNKI and PubMed (1980-2013) was performed for relevant articles addressing the telescopic crown using the keywords of “cone sleeve crown, abutment, clinical observation” in Chinese and English, respectively. RESULTS AND CONCLUSION:Telescopic crown-retained removable partial dentures

  12. Marginal Strength of Collarless Metal Ceramic Crown

    Directory of Open Access Journals (Sweden)

    Sikka Swati

    2010-01-01

    fracture strength at margins of metal ceramic crowns cemented to metal tooth analogs. Crowns evaluated with different marginal configurations, shoulder and shoulder bevel with 0 mm, 0.5 mm, 1 mm, and 1.5 mm, were selected. Methods. Maxillary right canine typhodont tooth was prepared to receive a metal ceramic crown with shoulder margin. This was duplicated to get 20 metal teeth analogs. Then the same tooth was reprepared to get shoulder bevel configuration. These crowns were then cemented onmetal teeth analogs and tested for fracture strength atmargin on an Instron testing machine. A progressive compressive load was applied using 6.3 mm diameter rod with crosshead speed of 2.5 mm per minute. Statisticaly analysis was performed with ANOVA, Student's “t” test and “f” test. Results. The fracture strength of collarless metal ceramic crowns under study exceeded the normal biting force. Therefore it can be suggested that collarless metal ceramic crowns with shoulder or shoulder bevel margins up to 1.5 mm framework reduction may be indicated for anteriormetal ceramic restorations. Significance. k Collarless metal ceramic crowns have proved to be successful for anterior fixed restorations. Hence, it may be subjected to more clinical trials.

  13. 牙冠延长术应用于后牙残根的临床研究%Clinical Report of Application in Residual Root of Molar Crown Lengthening Surgery

    Institute of Scientific and Technical Information of China (English)

    莫浩勋; 卢建峰; 李衬眉

    2011-01-01

    Objective To observe the clinical effect of restoration of residual root of molar with crown lengthening surgery. Methods Fifteen residual roots were included in this study. Crown lengthening surgery was first conducted and then post-core crowns were fabricated in all the cases. Then clinical effects were evaluated. Results All cases succeeded. The color of the gingival margin looked normal and the crowns were in good periodontal condition. Conclusion Crown lengthening surgery is an effective method for the protection and restoration of residual root,but should be used properly.%目的 观察牙冠延长术应用于后牙残根保留的效果.方法 选取远中缺损的后牙残根15颗,患者15例,应用牙冠延长术完成牙周软组织和牙槽骨硬组织的外科治疗,形成牙本质肩领,术后1周拆线,3个月后行桩核及冠桥修复.永久修复后2周复查,观察疗效.结果 15颗后牙残根无不适症状,术区牙龈颜色、形态和质地恢复正常,修复体无松动、脱落,基本恢复咀嚼功能,患者满意.结论 牙冠延长术有利于后牙残根的保留和修复,但要注意适应证的选择.

  14. Clinical evaluation of periodontal disease caused by anterior tooth crown restoration%前牙不良冠修复引发牙周病的临床治疗评估

    Institute of Scientific and Technical Information of China (English)

    刘京津

    2016-01-01

    目的:探讨和研究前牙不良冠修复所致牙周病的临床疗效。方法:选取自2014年2月到2015年2月在我院进行治疗的前牙不良冠修复所致牙周病患者40例作为研究对象,患牙共230颗,对所有的患者在采用牙周基础治疗与牙冠延长术的基础之上,再进行全瓷冠修复,并对患者的临床治疗状况进行观察。结果:术前患者的探针深度与探针出血和术后两个月的临床记录差异明显,差异有统计学意义(P<0.05)。结论:医护人员对患者在采用牙周基础治疗与牙冠延长术的基础上,再进行全瓷冠修复,可以促进牙周病的快速康复,对于促进牙周健康成长,具有良好的临床治疗效果,值得在临床上进一步推广和利用。%Objective To explore and crowns of anterior teeth due to adverse clinical effects of periodontal disease.Methods From February 2014 to February 2015 in our hospital for treatment of anterior teeth due to periodontal bad crowns of 40 patients for the study, a total of 230 teeth, for all patients in the use of dental base-week baseline and crown lengthening surgery above, then all-ceramic crowns, and clinical status of patients was observed.Results The probe depth probe with the clinical records of patients with bleeding and postoperative months preoperative significant difference, and the difference was statistically significant (P <0.05).Conclusion On the basis of the use of health care for patients with periodontal therapy on crown lengthening surgery, and then the all-ceramic crowns, periodontal disease can contribute to a quick recovery for the promotion of periodontal healthy growth, with good clinical results worthy of further promotion and use in clinical practice.

  15. Efficiency of 2 electronic apex locators on working length determination: A clinical study

    Directory of Open Access Journals (Sweden)

    Sibel Koçak

    2013-01-01

    Full Text Available Aims: The aim of this clinical study was to evaluate the clinical accuracy of two electronic apex locators (EALs. Materials and Methods: A total of 120 patients with 283 roots were randomized into three groups including, traditional radiographic method, EAL (Root ZX mini, and apex locating endodontic motor (VDW Gold for working length (WL determination. Root canals were instrumented to a size ProTaper F3 nickel titanium file. The obturation quality of matched tapered master cone (ProTaper F3 was determined for the accuracy of WL. Statistical Analysis Used: Descriptive statistics were expressed as numbers and percentages. Pearson Chi-square test was used to determine for differences between groups. P < 0.05 was considered statistically significant for all tests. Results: There was no statistically significant difference between the three tested groups ( P = 0.894. Conclusions: The success of both apex locators was similar to the radiographic WL determination technique.

  16. 折裂和龋坏形成的残冠残根牙冠延长术后的临床效果比较%Comparison of clinical effect of crown lengthening surgery between residual crowns and roots caused by teeth fracture or caries

    Institute of Scientific and Technical Information of China (English)

    范亚贤; 刘桂荣

    2014-01-01

    Objective To investigate the clinical effect of crown lengthening surgery of different kinds of residual crowns and roots and its influencing factors. Methods A total of 120 residual crowns and roots of 96 patients were selected for crown lengthening in this study. The 120 teeth were divided into two groups according to the reasons that lead to residual crowns and roots,group F ( caused by fracture) and group C ( caused by caries) . The locations of defects and probing depths of subgingival margin of the residual crowns and roots were recorded and compared before surgery. The patients were followed up for 4 to 6 weeks after surgery and the clinical effects evaluated and compared. Results In group F,the teeth defects were mainly located on palatal( lingual) sides,and in group C,the teeth defects were located on proximal or labial ( buccal ) sides. Probing depths of teeth margin before surgery in group F were much higher than those in group C(P<0. 01). Thirty-four teeth(54. 8%) in group F (total 62) and 48 teeth (82. 8%) in group C (total 58)obtained satisfactory effect(P<0. 01). Conclusion Residual crowns and roots caused by caries could achieved better clinical effect than those caused by fracture for crown lengthening.%目的:比较不同类型残冠、残根行牙冠延长术后的临床疗效及影响因素。方法选取来我科就诊,需行牙冠延长术的96名患者,行牙冠延长术的残冠、残根120颗。根据残冠残根形成的原因分为2组,折裂组和龋坏组。记录并比较2组牙体缺损所累及的牙面,及术前断缘的探诊深度,观察术后4~6周根断面暴露情况。结果2组缺损累及牙面不同,折裂组多发生在腭(舌)侧,龋坏组多发生在邻面或唇(颊)侧( P<0.01);折裂组术前断缘的探诊深度明显高于龋坏组(P<0.01);62颗牙因折裂行冠延长术后满意者34颗牙(54.8%),58颗牙因龋坏行冠延长术后满意者48颗牙(82.8%),差异有统计学意义(P<0.01)

  17. The clinical effect of minimally invasive crown lengthening%微创牙冠延长术的临床疗效评价

    Institute of Scientific and Technical Information of China (English)

    汪涌; 陈莹; 姚莉莉

    2016-01-01

    Objective:The goal of this investigation was to evaluate the clinical effect of minimally inva-sive technique in crown lengthening.Method:Thirty-nine patients with 45 teeth defects 1.5-4 mm below gingiva were randomly divided into two groups.The crowns were lengthened with traditional method in control groud(22 patients with 24 teeth),and experimental group(17 patients with 21 teeth) used minimally invasive technique:surgery was performed with the aid of an operating microscope and microsurgical instrument, the crown were lengthened with piezosurgery,5-0 stitches in suture.Probing depth( PD) ,sulcus bleeding index( SBI) and mobili-ty degree( MD) were measured before surgery and one week,8 weeks after surgery,and 6 months after prosthodon-tic.Gingival recession( GR) was measured at 6 months after prosthodontic treatment,and recorded the postopera-tive adverse reactions.Results:SBI,PD at one week after surgery in two groups were obviously improved which compared with presurgical(P0.05) .At 1 week after surgery experimental group the SBI and PD is better than that of control group,the differences between two groups was statistically significant(P<0.01).At 8 weeks postsurgery and 6 months after prosthodontic treatment PD in experimental group is lower than control group(P<0.01),the improvement of SBI is superior to the control group(P<0.05).GR was observed in 6 teeth of control group 6 month after prosthodontic,and there are 4 cases with postoperative swelling and 3 cases with postoperative pain in control group,but not observed in experimental group(P<0.05)Conclusion:Minimally invasive technol-ogy in crowns lengthening can obviously improve the clinical indicators, reduce postoperative adverse reactions and gingival recession.%目的:评价微创技术应用于牙冠延长术的临床效果。方法:将39例患者的45颗冠缺损达龈下最深位点1.5~4 mm患牙进行随机分组。对照组24颗患牙施行常规牙冠延长术;实验组21颗患牙是

  18. The clinical application of Cerec3D inlay crown in restoring extensively damaged molar%Cerec3D嵌体冠修复后牙大面积牙体缺损的临床应用

    Institute of Scientific and Technical Information of China (English)

    吕晶; 李东霞; 杨捷绯; 邓天政; 柯杰

    2015-01-01

    ObjectiveTo compare the clinical effect of Cerec3D inlay crown with post crown in restoration of extensively damaged molar and provide basis for clinical use in future.MethodsPatients were divided into 2 groups randomly. In group 1, teeth were restored using Cerec 3D inlay crown (inlay crown group). In group 2, teeth were restored using Cerec3D post crown (post crown group). All patients were evaluated based on USPHS measure and gingival index. Statistical analysis with SPSS 15.0 package was carried out.ResultsThere were 53 patients with 63 teeth in inlay crown group, of which 4 patients (5 teeth) were lost. There were 47 patients with 63 teeth in post crown group, of which 4 patients (4 teeth) were lost. No significant differences were observed in the two groups.ConclusionCerec3D inlay crown is suitable for restoring extensively damaged molar, and could perform masticatory function.%目的:本研究利用Cerec3D嵌体冠修复系统修复后牙大面积牙体缺损,并与传统桩冠修复进行临床比较,为今后的临床应用提供研究基础。方法选择行后牙冠修复的患者并随机分为2组。一组采用嵌体冠修复患牙(嵌体冠组),另一组采用桩冠修复患牙(桩冠组),2组进行对比追踪观察,所有入组患者在修复后不同时间点进行改良USPHS检查指标、分级标准和牙龈指数评价。采用SPSS 15.0统计学软件包进行数据统计学分析。结果嵌体冠组53例(63颗患牙),失访4例(5颗患牙);桩冠组47例(63颗患牙),失访4例(4颗患牙)。2组修复后复查,各项指标各时间段组间及组内比较差异均无统计学意义(P>0.05)。结论 Cerec3D嵌体冠适用于后牙大面积牙冠缺损的修复治疗,能够正常行使口颌功能。

  19. Clinical Frailty Scale in an Acute Medicine Unit: a Simple Tool That Predicts Length of Stay

    Science.gov (United States)

    Juma, Salina; Taabazuing, Mary-Margaret; Montero-Odasso, Manuel

    2016-01-01

    Background Frailty is characterized by increased vulnerability to external stressors. When frail older adults are admitted to hospital, they are at increased risk of adverse events including falls, delirium, and disability. The Clinical Frailty Scale (CFS) is a practical and efficient tool for assessing frailty; however, its ability to predict outcomes has not been well studied within the acute medical service. Objective To examine the CFS in elderly patients admitted to the acute medical ward and its association with length of stay. Design Prospective cohort study in an acute care university hospital in London, Ontario, Canada, involving 75 patients over age 65, admitted to the general internal medicine clinical teaching units (CTU). Measurements Patient demographics were collected through chart review, and CFS score was assigned to each patient after brief clinician assessment. The CFS ranges from 1 (very fit) to 9 (terminally ill) based on descriptors and pictographs of activity and functional status. The CFS was collapsed into three categories: non-frail (CFS 1–4), mild-to-moderately frail (CFS 5–6), and severely frail (CFS 7–8). Outcomes of length of stay and 90-day readmission were gathered through the LHSC electronic patient record. Results Severe frailty was associated with longer lengths of stay (Mean = 12.6 ± 12.7 days) compared to mild-to-moderate frailty (mean = 11.2 ± 10.8 days), and non-frailty (mean = 4.1 ± 2.1 days, p = .014). This finding was significant after adjusting for age, sex, and number of medications. Participants with higher frailty scores showed higher readmission rates when compared with those with no frailty (31.2% for severely frail, vs. 34.2% for mild-to-moderately frail vs. 19% for non-frail) although there was no significant difference in the adjusted analysis. Conclusion The CFS helped identify patients that are more likely to have prolonged hospital stays on the acute medical ward. The CFS is an easy to use tool which

  20. Clinical application of the surgical crown lengthening combining all ceramic crown after failure of the anterior teeth PFM crown restoration%牙冠延长术结合全瓷冠修复在前牙烤瓷冠失败病例的应用

    Institute of Scientific and Technical Information of China (English)

    李雪峰

    2013-01-01

    目的:探讨应用牙冠延长术结合全瓷冠技术治疗前牙生物学宽度不足导致不良烤瓷冠修复的临床疗效。方法选取26例因生物学宽度不足导致的前牙修复失败病例,进行完善牙周治疗,根管治疗,并进行牙冠延长术后全瓷冠修复,观察术前,术后六周以及修复后三个月以及修复六个月的PD(探诊深度), SBI(出血指数)并予以记录。结果24例患者治疗效果较好,两例术后牙龈高度不对称,患者不甚满意。结论牙冠延长术结合全瓷冠修复可以较好的解决前牙不良烤瓷冠修复的再治疗问题。%Objective To investigate the effect after crown lengthening surgery combining all ceramic crown on anterior teeth failure of PFM crown restoration because of insufficient biological width Methods Select 26 failure cases of anterior teeth caused by insufficient biological width , repair to perfect the periodontal treatment, root canal treatment, and crown lengthening surgery. After treatment all teeth were restored by all ceramic crown, At baseline, 6 weeks after surgery and 3 months and 6 months after the restoration BOP and PD were recorded and analyzed. Results 24 patients treatment effect is good, two cases of postoperative were not very satisfied because of gum hight asymmetric. Conclusion Crown lengthening sursery combining all ceramic crown restoration can solve the failure PFM restoration on anterior teeth.

  1. 冠延长术在前牙桩核冠修复失败后的临床应用%Clinical application of the surgical crown lengthening after failure of the anterior teeth post crown restoration

    Institute of Scientific and Technical Information of China (English)

    彭蓓; 储雯; 季娟娟; 张婉丽; 杨杨; 王祥芸; 张晓渝

    2012-01-01

    20 subjects with tooth defect 3 nun below gingival margin underwent surgical crown lengthening SCL) after complete periodental non-surgical treatment. Probing depth(PD) and sulcus bleeding index(SBI) were measured before and after operation. PD decreased 2 weeks after operation (P 0.05). SBI decreased step by step 2-6 weeks after operation(f <0.05). 6 weeks after SCL gingival margin was stable, Dowel crown was restored and satisfied results were obtained.%纳入20例牙体缺损达龈下(≤3 mm)修复失败的前牙,经完善牙周基础治疗后行冠延长术,记录术前、术后2、4、6周牙周袋探诊深度(PD)、龈沟出血指数(SBI).PD值术后2周减小(p<0.05),术后2、4、6周间差异无显著性(p>0.05);SBI值术后减小,2周与术前、术后4、6周差异存在显著性(p<0.05).术后6周龈缘位置相对稳定,此时行桩核冠修复,成功率较高.牙冠延长术可提高残根的修复质量和效果.

  2. Anatomic and functional leg-length inequality: A review and recommendation for clinical decision-making. Part I, anatomic leg-length inequality: prevalence, magnitude, effects and clinical significance

    Directory of Open Access Journals (Sweden)

    Knutson Gary A

    2005-07-01

    Full Text Available Abstract Background Leg-length inequality is most often divided into two groups: anatomic and functional. Part I of this review analyses data collected on anatomic leg-length inequality relative to prevalence, magnitude, effects and clinical significance. Part II examines the functional "short leg" including anatomic-functional relationships, and provides an outline for clinical decision-making. Methods Online database – Medline, CINAHL and MANTIS – and library searches for the time frame of 1970–2005 were done using the term "leg-length inequality". Results and Discussion Using data on leg-length inequality obtained by accurate and reliable x-ray methods, the prevalence of anatomic inequality was found to be 90%, the mean magnitude of anatomic inequality was 5.2 mm (SD 4.1. The evidence suggests that, for most people, anatomic leg-length inequality does not appear to be clinically significant until the magnitude reaches ~ 20 mm (~3/4". Conclusion Anatomic leg-length inequality is near universal, but the average magnitude is small and not likely to be clinically significant.

  3. Crown lengthening and restorative treatment in mutilated molars.

    Science.gov (United States)

    Parashis, A; Tripodakis, A

    1994-03-01

    Crown lengthening has been advocated as a treatment modality to restore teeth with a clinical crown reduced subsequent to different kinds of trauma. Multirooted teeth, however, present certain anatomic features, such as the furcation area and corresponding interradicular bone, the retromolar area, and the external oblique ridge, that may limit the possibility for soft tissue and bone reduction and minimize the effectiveness of crown-lengthening procedures. This article describes surgical modifications to overcome the anatomic difficulties that multirooted teeth present when crown lengthening is required. Furthermore, root resection is discussed as an alternative to conventional surgery when the latter is not possible.

  4. Crown Fire Potential

    Data.gov (United States)

    Earth Data Analysis Center, University of New Mexico — Crown fire potential was modeled using FlamMap, an interagency fire behavior mapping and analysis program that computes potential fire behavior characteristics. The...

  5. IPSe.max Press铸瓷全冠修复效果的临床观察%A short term clinical evaluation of IPS e.max Press all-ceramic crowns

    Institute of Scientific and Technical Information of China (English)

    吴文生; 徐培成; 周曼莉

    2011-01-01

    目的:评价IPS e.max Press铸瓷全冠的临床修复效果.方法:对41例患者127颗前牙和前磨牙进行IPS e.maxPress热压铸瓷全冠修复,修复后12~42个月(平均28个月),参照美国公共卫生服务修正标准对修复体的颜色匹配、边缘着色、修复体折裂、继发龋、边缘适合度以及牙龈健康情况进行评价.结果:在颜色匹配方面,94.49%的修复体表现为A级,5.51%表现为B级;1.57%的全冠出现边缘着色;1颗(0.79%)修复体出现饰面瓷折裂;未发现继发龋;94.49%的修复体边缘适合度表现为A级,5.51%表现为B级;在牙龈健康方面,93.70%的修复体表现为A级,4.72%表现为B级,1.58%表现为C级.结论:在平均28个月的临床观察中,IPS e.max Press铸瓷全冠临床修复效果优良.%PURPOSE: The aim of this study was to evaluate the clinical effect of IPS e.max Press crowns. METHODS: A total of 127 IPS e.max Press crowns was placed in forty-one patients from 2007 to 2009. The crowns were evaluated with a modified USPHS criteria for color match, marginal discoloration, fracture, secondary caries, marginal adaptation and gingival health for a period of 12 to 42 months, with a mean of 28 months after insertion. A,B,C and D ratings were assigned. RESULTS: 94.49% of the crowns were rated as A and 5.51% rated as B for color match and marginal adaptation. 1.57% of the crowns was detected with marginal discoloration and one crown (0.79%) was detected with veneer chipping. No secondary caries was detected, and 93.70% of the crowns were rated as A, 4.72% rated as B and 1.58% rated as C for gingival health. CONCLUSION: IPS e.max Press crowns exhibit excellent clinical performance over a mean evaluation period of 28 months.

  6. Observation on the clinical curative effect of porcelain fused to metal crown restoration of dental fluorosis%金属烤瓷冠修复氟斑牙临床疗效观察

    Institute of Scientific and Technical Information of China (English)

    唐春科

    2014-01-01

    Objective:To investigate the clinical application effect of porcelain fused to metal crown for restoration of dental fluorosis and the appearance of anterior teeth repair.Methods:16 patients with dental fluorosis were required aesthetics of anterior teeth.They were taken porcelain fused metal crown to restorate 98 dental fluorosis of cosmetic repair,then followed-up for 3 years and comprehensive evaluated the therapy effect.Results:After 3 years of follow-up,the shape and color of all the 98 teeth did not change,and also kept a good function.Conclusion:Using porcelain fused to metal crown restoration of anterior teeth can provide beautiful appearance,vivid color,smooth and wear characteristics,so we can concluded that metal porcelain crown has a good effect on the restoration of dental fluorosis cosmetic repair.%目的:探讨金属烤瓷冠用于修复氟斑牙的临床应用效果及对前牙的美观修复情况。方法:16例氟斑牙患者要求前牙美观,采用金属烤瓷冠对98颗氟斑牙进行美容修复,进行3年随访,综合评价。结果:随访3年,98颗金属烤瓷冠修复后色泽形态良好,功能良好。结论:金属烤瓷冠修复前牙具有美观、色泽逼真、光滑耐磨等特点,金属烤瓷冠对氟斑牙美容修复有着良好的修复效果。

  7. Orthodontic traction of post crown restoration of traumatic anterior tooth after crown lengthening effect evaluation of clinical%正畸牵引联合冠延长术后桩冠修复外伤前牙的临床效果评价

    Institute of Scientific and Technical Information of China (English)

    曾翠敏; 赵世俊; 马东湘; 于兰; 胡姝娥

    2013-01-01

    目的:观察正畸牵引与冠延长术后桩冠修复前牙龈下根折的治疗效果.方法:选择60颗断端位于龈下3mm以上的外伤前牙进行正畸牵引至平龈后行冠延长术,分别记录术前、桩冠修复前、修复后3个月、6个月及12个月的牙周探诊深度(PD)、龈沟出血指数(SBI)、牙齿松动度(TM),观察临床效果.结果:所有病例术前、修复前、修复后3个月、6个月及12个月的PD、SBI、TM值均有显著改善,差异有统计学意义,TM在修复前明显增加,但随时间延长逐渐稳定.结论:正畸牵引与冠延长术、桩冠修复外伤前牙断端位于龈下3 mrn以上的患牙,取得较好的临床效果.%Objective:Observation of orthodontic traction with post Crown restoration after Crown lengthening surgery prior to the trauma treatment effect of root fracture under gingiva.Method:Select more than 60 off-side in the Sub-gingival 3mm traumatic anterior tooth for orthodontic traction to gingivitis down Crown lengthening,recorded before and after post Crown restoration,repair,before a three-month,six-month and one-year observation of periodontal probing depth,PD (PD),the gingival sulcus bleeding index (SBI),loose teeth (TM),and observe the clinical effects.Result:All cases before and after before restoration,repair of the year in March,June,and PD,SBI,TM values has significantly improved,differences are statistically significant,TM significantly increased before the repair,but gradually stabilizing over time.Conclusion:This method for traumatic anterior teeth broken ends in Sub-gingival teeth of 3mm reserved for better clinical results.

  8. Care and Aftercare Related to Implant-Retained Dental Crowns in the Maxillary Aesthetic Region : A 5-Year Prospective Randomized Clinical Trial

    NARCIS (Netherlands)

    Visser, Anita; Raghoebar, Gerry M.; Meijer, Henny J. A.; Meijndert, Leo; Vissink, Arjan

    2011-01-01

    Aim: To prospectively assess surgical and prosthetic care and aftercare related to the placement of implant-retained dental crowns after local bone augmentation in patients missing one tooth in the maxillary aesthetic region. Methods: Ninety-three patients were randomly allocated to one of three loc

  9. Clinical Comparison of Root Length Measurements with Electronic Apex Locator and Conventional Radiography in Mandibular Deciduous Teeth

    OpenAIRE

    Eskandarian T; Sahebi S.; Amirabadi F.; Alipour A

    2011-01-01

    Statement of Problem: Success in pulpectomy of deciduous teeth greatly depends on the accuracy of root length measurements which have mostly been done radiographically. However, X-ray risks and patient cooperation have usually been a challenge for the clinicians.Purpose: The clinical comparison of root length measurements with electronic apex locator and conventional radiography in 4-6 year old children's mandibular deciduous teeth was the aim of the present study.Materials and Method: In the...

  10. Telomere length in non-neoplastic colonic mucosa in ulcerative colitis (UC) and its relationship to the severe clinical phenotypes.

    Science.gov (United States)

    Tahara, Tomomitsu; Shibata, Tomoyuki; Okubo, Masaaki; Kawamura, Tomohiko; Sumi, Kazuya; Ishizuka, Takamitsu; Nakamura, Masakatsu; Nagasaka, Mitsuo; Nakagawa, Yoshihito; Ohmiya, Naoki; Arisawa, Tomiyasu; Hirata, Ichiro

    2015-08-01

    Telomere shortening occurs with human aging in many organs and tissues and is accelerated by rapid cell turnover and oxidative injury. To clarify the clinical importance of telomere shortening in colonic mucosa in ulcerative colitis (UC), we measured average telomere length using quantitative real-time PCR in non-neoplastic colonic mucosa in UC patients and assessed its relationship to various clinical subtypes. Relative telomere length in genomic DNA was measured in colonic biopsies obtained from rectal inflammatory mucosa from 86 UC patients as well as paired non-inflammatory proximal colonic mucosae from 10 patients. Data were correlated with various clinical phenotypes. In paired samples, average relative telomere length of rectal inflammatory mucosa was shortened compared to normal appearing proximal colon in eight out of ten cases (p = 0.01). Telomere length shortening was significantly associated with more severe Mayo endoscopic subscore (p telomere length was significantly shortened in the same phenotypes than the others (p = 0.003). Telomere shortening is associated with more severe clinical phenotypes of UC, reflecting severe inflammatory state in the colonic mucosa.

  11. Clinical study on periodontal assessment of three different porcelain crowns/bridges%三种烤瓷冠桥修复后牙周状况分析

    Institute of Scientific and Technical Information of China (English)

    刘惠莉

    2011-01-01

    Objective To evaluate the effect of Co - Cr alloy PFM, Au - Pt alloy PFM, zirconia all ceramic crowns/bridges on periodontal health. Methods Totally 278 teeth from 152 patients were respectively restored by Co - Cr alloy, Au - Pt alloy and zirconia all ceramic crowns/bridges. Follow up three years and compare the color of gingival, gingival index (Gl), plaque index (PLI) , and the change of probing depth (PD). Results After three years, 27.2% cases restored by Co - Cr alloy PFM crowns/bridges and 5.15% Au - Pt alloy PFM crowns/bridges showed the change of gingival color. But the effect of zirconia all ceramic crowns/bridges on gingival color was none. Cases restored by Co- Cr alloy PFM crowns/bridges and Au -Pt alloy PFM crowns/bridges showed significant difference in GI and PLI between pre- and post -restoration ,while no significant difference in PD. There are no significant difference in zireonia all ceramic crowns/bridges of the GI, PLI and PD. Conclusions CoCr alloy PFM of periodontal tissue, the biggest influence , Au -Pt alloy PFM next, zirconia all ceramic crowns/bridges of periodontal tissue affect the minimum, but it still need to be observed further.%目的 观察钴铬合金烤瓷冠、金铂合金烤瓷冠和氧化锆全瓷冠对牙周组织的影响.方法 对152例患者的278颗牙分别经钴铬合金烤瓷、金铂合金烤瓷和氧化锆全瓷冠桥修复后3年复查,观察修复前后基牙牙龈色泽、牙龈指数、菌斑指数和牙周探诊深度的变化.结果 27.2%钴铬合金烤瓷冠和5.15%的金铂合金烤瓷在修复后3年牙龈变色,氧化锆全瓷冠组牙龈无变色;钴铬合金组和金铂合金组的牙龈指数、菌斑指数与修复前比较有显著差异(P0.05).氧化锆全瓷组牙周指数与修复前比较均无显著差异(P>0.05).结论 钴铬合金烤瓷冠对牙周组织影响最大,金铂合金烤瓷冠次之,氧化锆全瓷冠对牙周组织影响最小,但其远期效果还需进一步观察.

  12. A comparative study of the clinical effects on the treatment of the subgingival defects of the upper anterior teeth by modified crown lengthening surgery and by crown lengthening surgery with orthodontic traction%改良牙冠延长术与正畸牵引加牙冠延长术治疗上前牙龈下牙体缺损的疗效比较

    Institute of Scientific and Technical Information of China (English)

    雷琼; 陈燕

    2012-01-01

    Objective The purpose of the study is to compare the clinical effects on the treatment of the subgingival defect of the upper anterior teeth by modified crown lengthening surgery and by crown lengthening surgery with Orthodontic traction. Methods 54 upper anterior teeth from 46 patients were divided into two groups randomly, including 27 teeth in the observation group treated by crown lengthening surgery with orthodontic traction and 27 in the control group treated by modified crown lengthening surgery. The difference of indexes before and after treatment in the two groups. Results The indexes such as PPD, GI and TM were improved statistically after treatment ( P 0.05 ) . Conclusion Both the modified crown lengthening surgery and the crown lengthening surgery with orthodontic traction can be applied to treat the subgingival defect of the upper anterior teeth.[ Key words ] modified crown lengthening surgery; crown lengthening surgery with orthodontic traction; subgingival defects%目的 比较改良牙冠延长术与正畸牵引加牙冠延长术对上前牙龈下牙体缺损的治疗效果.方法 选择上前牙龈下牙体缺损患者46例(54颗牙),随机均分为两组.对照组采用改良牙冠延长术治疗,观察组采用正畸牵引加牙冠延长术治疗.比较治疗前后两组患者治疗后各指标的差异.结果 与治疗前比较,两组患者PPD、GI、TM等指标均有不同程度的改善,差异有统计学意义(P<0.05).两组患者之间比较,差异无统计学意义(P>0.05).结论 改良牙冠延长术与正畸牵引加牙冠延长术对上前牙龈下牙体缺损均有较好的治疗效果,临床工作中可根据患者情况选择使用.

  13. [Surgical crown lengthening procedures. Preparatory step for fixed prosthesis].

    Science.gov (United States)

    Parashis, A O; Tripodakis, A P

    1990-04-01

    Necessary restorative requirements for full coverage are adequate axial wall height of the preparation for retention as well as sufficient vertical width of sound tooth structure cervically for the crown margins. In cases where adequate healthy tooth structure does not exist coronally to the epithelial attachment due to various crown damages, the margins of the crown might traumatize the periodontal attachment and the periodontium will be jeopardized iatrogenically. Teeth with inadequate axial Reight of the clinical crown, subgingival caries, vertical or horizontal fractures will require surgical crown lengthening procedures before prosthetic treatment is performed. These procedures may either involve only the soft tissues or bone remodeling as well. Irrespective of the procedure, crown lengthening must be performed with the objective of at least 3 mm. of healthy tooth structure coronally to the bone. This width will permit the formation of a new dentinogingival junction and the existence of 1-2 m.m. of sound tooth structure coronally to the new attachment line for the construction of a biologically acceptable crown margin. The purpose of this article is to discuss the clinical problem and underline the importance of crown lengthening procedures as a preparatory step for prosthetic treatment in fixed partial dentures.

  14. Crown lengthening revisited.

    Science.gov (United States)

    Rosenberg, E S; Cho, S C; Garber, D A

    1999-06-01

    Over the last 37 years, crown-lengthening procedures have been used predictably to restore teeth broken down from caries, trauma, and extensive wear. With crown lengthening, the dentogingival junction is "re-created" at a more apical level on the root to accommodate the junctional epithelium and the connective tissue attachment. Forced eruption can be used in addition, or as an alternative, to tooth lengthening. The authors discuss the indications for tooth lengthening, forced eruption, and orthodontic extrusion, as well as the treatment planning for these procedures.

  15. 牙冠延长术用于劈裂牙修复中的临床研究%Clinical study of broken tooth restored with crown lengthening surgery

    Institute of Scientific and Technical Information of China (English)

    周娟; 杜姗姗; 解龙川; 罗志晓; 柴红波

    2011-01-01

    Objective It is to evaluate the clinical effect of crown lengthening surgery on restoration of broken tooth.Methods 43 teeth from 38 patients with subgingivally involved defect were divided into two groups : group A ( 24 teeth, 1 mm < depth < 3 mm ), Group B ( 19 teeth, 3 mm≤ depth≤4 mm ). All teeth were treated by crown lengthening first and then accepted crown prosthesis at 6 weeks postoperatively. The PLI, SBI, PD and odontoseisis degree of pre - and post - operative were recorded, and the clinical effect was observed. Results After 6 weeks, the teeth sections of two groups were exposed well and the color of gingival margin of two groups looked normal, there was no tooth loosed in Group A and were 42% teeth with loose at degree Ⅰ in Group B. After 6 months, there was no tooth in Group A, the effect was satisfactory; and there were 47% teeth with loose at degree Ⅰ, the effect wan not satisfactory. There was significant difference between both groups ( P < 0. 01 ).Postoperative PLI, SBI and PD were better than those preoperatively ( P < 0. 05 ), but there was no significant difference between both groups ( P > 0. 05 ). The effective rate was 100 % of both groups, and satisfactory rate was 100% in Group A and 53% in Group B. Conclusion Crown lengthening surgery can rebuild the biological width of broken teeth; it is a good method for the protection and restoration of broken tooth, but should he strictly grasped the clinical indication.%目的 评价牙冠延长术在劈裂牙修复中的临床效果.方法 对38例43颗劈裂牙,按断端位于龈下最深距离分为A组(24颗患牙,1mm0.05).术后2组修复有效率100%;A组满意率100%,B组53%.结论 牙冠延长术能重建劈裂牙的生物学宽度,有利于劈裂牙的保存和修复,但要严格把握临床适应证.

  16. Clinical effect on the subgingival tooth defect of the anterior teeth crown after surgical crown lengthening%牙体缺损达龈下前牙行牙冠延长术后冠修复的临床效果

    Institute of Scientific and Technical Information of China (English)

    卢文博; 王京阳

    2015-01-01

    subgingival tooth defect located 2-4 mm, treated with boneless and bone flap angioplasty. They were given full crown restoration after 6-8 weeks. The repair effects, sulcus bleeding index (SBI), plaque index (PLI), loose degrees (TM), extend the height of the crown, black triangle incidence before and after restoration were compared. Results①There were 41 teeth of defects section exposed, no loose after operation; only 1 case occurred teeth crown off, the rest was good 1 year after restoration.②SBI (0.98, 0.76), PLI (0.70, 0.44) 6 weeks after surgery, 12 weeks after surgery were lower than before surgery (2.35,1.52), TM (0.65, 0.52) was higher than before surgery (0.37), the differences were statistically significant (P<0.05).③The height of the prolonged crown 6 weeks after surgery [(3.02±0.51) mm], 12 weeks after surgery [(3.24±0.59) mm] were higher than 2 weeks after surgery [(2.35±0.46) mm], the differences were statisti-cally significant (P<0.05).④There were significant differences in the incidence of black triangle among repair imme-diately (78.05%), 6 months after repair (21.95%), 12 months after repair (19.51%), the difference was statistically sig-nificant (P< 0.05). ⑤12 months after repair SBI (1.14), PLI (0.71) were higher than repaired immediately (0.76, 0.44), the differences were statistically significant (P< 0.05). Conclusion Under strict control of surgical crown lengthening and postoperative indications repair methods and the proper periodontal care, subgingival tooth defect of the anterior teeth crown can obtain satisfactory clinical results.

  17. 金属预成冠修复儿童乳磨牙大面积缺损的临床疗效观察%Clinical therapeutic effects of metal crown for massive destruction in deciduous molar

    Institute of Scientific and Technical Information of China (English)

    邓卓峰; 周峥

    2013-01-01

    OBJECTIVE To investigate therapeutic effect of metal crown for massive destruction in deciduous molar. METHODS 80 teeth of 76 patients with massive destruction in deciduous molar were chosen in the period from January 2007 to September 2011 in our hospital and randomly divided into two groups including the control group (40 teeth of 38 patients) treated with cured resin and the treatment group (40 teeth of 38 patients) treated with metal crown; and the clinical success rate in 6 and 12 months after operation of both groups and the gingival index of metal crown treatment group before and after operation were compared. RESULTS There was no significant difference in the clinical success rate in 6 months after operation between control group and metal crown treatment group (P> 0.05). The clinical success rate in 12 months after operation of metal crown treatment group were significantly better than control group (P 0.05). CONCLUSION Compared with cured resin treatment, metal crown for massive destruction in deciduous molar can efficiently promote occlusion recovery, improve the success rate, and has no significant effect on the gums state.%目的 探讨金属预成冠修复儿童乳磨牙大面积缺损临床效果.方法 选取某院2007年1月~2011年9月收治乳磨牙大面积缺损患儿76例80颗牙,采用随机数字表法分为两组,其中对照组38例40颗牙,采用固化树脂修复;金属预成冠组38例40颗牙,采用金属预成冠修复.比较两组患儿术6个月、12个月临床治疗成功率;同时比较金属预成冠组患儿手术前后牙龈指数组间差异.结果 对照组与金属预成冠组患儿术后6个月临床治疗成功率组间比较差异无统计学意义(P>0.05);但金属预成冠组患儿术后12个月临床治疗成功率均合关系恢复,提高修复成功率,且对于牙龈状态无明显影响.结论 相较于固化树脂修复,金属预成冠修复儿童乳磨牙大面积缺损能够有效促进咬属预成

  18. Evaluation of bone remodeling around single dental implants of different lengths: a mechanobiological numerical simulation and validation using clinical data.

    Science.gov (United States)

    Sotto-Maior, Bruno Salles; Mercuri, Emílio Graciliano Ferreira; Senna, Plinio Mendes; Assis, Neuza Maria Souza Picorelli; Francischone, Carlos Eduardo; Del Bel Cury, Altair Antoninha

    2016-01-01

    Algorithmic models have been proposed to explain adaptive behavior of bone to loading; however, these models have not been applied to explain the biomechanics of short dental implants. Purpose of present study was to simulate bone remodeling around single implants of different lengths using mechanoregulatory tissue differentiation model derived from the Stanford theory, using finite elements analysis (FEA) and to validate the theoretical prediction with the clinical findings of crestal bone loss. Loading cycles were applied on 7-, 10-, or 13-mm-long dental implants to simulate daily mastication and bone remodeling was assessed by changes in the strain energy density of bone after a 3, 6, and 12 months of function. Moreover, clinical findings of marginal bone loss in 45 patients rehabilitated with same implant designs used in the simulation (n = 15) were computed to validate the theoretical results. FEA analysis showed that although the bone density values reduced over time in the cortical bone for all groups, bone remodeling was independent of implant length. Clinical data showed a similar pattern of bone resorption compared with the data generated from mathematical analyses, independent of implant length. The results of this study showed that the mechanoregulatory tissue model could be employed in monitoring the morphological changes in bone that is subjected to biomechanical loads. In addition, the implant length did not influence the bone remodeling around single dental implants during the first year of loading. PMID:26249362

  19. IPS e.max Press全瓷冠和三单位固定桥的临床评价%Clinical evaluation of IPS e.max Press all-ceramic crowns and three-unit fixed partial dentures

    Institute of Scientific and Technical Information of China (English)

    郭玲; 郑树灿; 罗祖凤; 覃峰; 徐亚娟; 付强

    2009-01-01

    Objective To evaluate the clinical performance of IPS e.max Press all-ceramic crowns and three-unit fixed partial dentures(FPDs)and to investigate the periodontal response to the presence of the restorations.Methods According to the inclusion criteria,19 patients with dental defects or singletooth loss were recruited,including 25 crowns and 6 all-ceramic FPDs.The modified United States Public Health Service criteria were used for follow-up evaluation.Plaque index(PI)and sulcus bleeding index (SBI)were recorded for the ceramic restorations and the control teeth.Results No crown and FPD fractures were observed during the evaluation period.There was no statistically significant difference regarding PLI and SBI scores between restorative teeth and the control teeth.And the difference between different recalled times of PLI and SBI of the restorations was no statistically significant.Conclusion IPS e.max Press crowns and three-unit fixed partial dentures exhibit a satisfactory clinical performance.%目的 探讨在牙科美容修复中应用IPS e.max Press全瓷冠桥的临床疗效及其对基牙牙周组织的影响,总结相关影响因素.方法 采用前瞻性研究的方法,对符合纳入标准的19例患者行IPS e.max Press全瓷冠或全瓷三单位固定桥修复,其中全瓷冠25例,全瓷三单位固定桥6例,参照改良美国公共健康协会标准,对其临床效果进行追踪评价,并记录修复体及对照牙菌斑指数(plague index,PLI)及龈沟出血指数(suleus bleading index,SBI).结果 经过3~12个月的临床追踪观察,无1例IPS e.maxPress修复体松动、折裂、脱落或被替换,修复体组和对照牙组的PLI及SBI的差异无统计学意义,修复体组在不同复诊时间PLI及SBI前后差异无统计学意义.结论 IPS e.max Press全瓷冠桥可获良好的近期临床效果.

  20. Development and clinical application of a length-adjustable water phantom for total body irradiation.

    Science.gov (United States)

    Chen, Zhi-Wei; Yao, Sheng-Yu; Zhang, Tie-Ning; Zhu, Zhen-Hua; Hu, Zhe-Kai; Lu, Xun

    2012-08-01

    A new type of water phantom which would be specialised for the absorbed dose measurement in total body irradiation (TBI) treatment is developed. Ten millimetres of thick Plexiglas plates were arranged to form a square cube with 300 mm of edge length. An appropriate sleeve-type piston was installed on the side wall, and a tabular Plexiglas piston was positioned inside the sleeve. By pushing and pulling the piston, the length of the self-made water phantom could be varied to meet the required patients' physical sizes. To compare the international standard water phantom with the length-adjustable and the Plexiglas phantoms, absorbed dose for 6-MV X ray was measured by an ionisation chamber at different depths in three kinds of phantoms. In 70 cases with TBI, midplane doses were metered using the length-adjustable and the Plexiglas phantoms for simulating human dimensions, and dose validation was synchronously carried out. There were no significant statistical differences, p > 0.05, through statistical processing of data from the international standard water phantom and the self-designed one. There were significant statistical differences, p body width. Obviously, the difference had a positive correlation with the body width. The results proved that the new length-adjustable water phantom is more accurate for simulating human dimensions than Plexiglas phantom.

  1. 牙冠延长术用于前牙冠修复的牙周指标分析%Periodontal index analysis of crown lengthening surgery for anterior teeth crown restoration

    Institute of Scientific and Technical Information of China (English)

    李隽; 刘晓峰

    2014-01-01

    目的:评价牙周基础治疗及牙冠延长术治疗前牙不良冠修复所致牙周病的临床疗效。方法:选取30例前牙冠修复所致牙周病患者共105颗患牙,均采用牙周基础治疗及牙冠延长术后再行冠修复,观察不同时段临床冠长度的变化,记录各相关牙周指数并进行分析,评估术后全冠修复的临床效果。结果:术后短期内临床冠长度增加效果确切,治疗组术后的各项牙周指数均优于术前(P<0.05),与对照组比较无明显差异(P>0.05),在1年的观察期内保持相对稳定(P>0.05);全冠修复体的固位良好,边缘密合,龈缘与冠缘的位置关系相对稳定。结论:牙周基础治疗及牙冠延长术有利于不良冠修复所致牙周病的治疗,且冠延长术解决了生物学宽度的问题,确保了牙周健康的长期稳定。%Objective:To evaluate the clinical effect of initial therapy and crown lengthening surgery on anterior teeth involved with periodontal disease after crown restored. Method:Initial therapy and crown lengthening surgery were applied to 105 anterior teeth of 30 cases. After treatment all teeth were restored by crowns. At different time we observe changes in clinical crown length,record relevant periodontal index and analyse and evaluate clinical effect of the postoperative crown restoration. Result:Postoperative clinical crown length had obvious short-term effect.The experiment group's postoperative periodontal index were superior to preoperative index(P0.05),and remained relatively stable in one-year observation period (P >0.05).The retention of crown prosthesis was bet-ter,and the margin was fitted well and relatively stable to the margin of gingival. Conclusion:Crown lengthening surgery solved the problem of biologic width. Therefore,right selection of indications,initial therapy,crown lengthening surgery and accurate restoration design contribute to the treatment of periodontal

  2. 不同材料修复残根、残冠的疗效评价%Evaluation of clinical effecs of the repairing residual roots and residual crowns with different materials

    Institute of Scientific and Technical Information of China (English)

    徐赏

    2001-01-01

    目的:比较银汞合金与复合树脂修复磨牙残根、残冠的疗效。方法:选取因患龋而成残根、残冠的下颌第一磨牙100个,在根管治疗术后,采用钉固位,分别以银汞合金或复合树脂修复,各50个牙,比较其疗效。追踪复查2年后的治疗效果。结果:银汞合金修复者,优45牙(90%),一般4牙(8%),失败1牙(92%)。复合树脂修复者,优40牙(80%),一般6牙(10%),失败4牙(8%)。两者成功率χ2检验,P>0.05。结论:银汞合金修复与复合树脂修复残根、残冠的疗效相差无显著性。%AIM:To compare the clinical effects of repairing the residual roots and residual crowns of molar teeth with silver amalgam or composite resin. METHODS: 100 lower first molars with residual roots or residual crowns by caries were chosen. After root canal therapy, pin retention was adopted, 50 were repaired ones with silver amalgam and 50 ones with composite resin. Then compare their clinical effects for two years. RESULTS: The clinical effects of silver amalgam group showed 45 teeth best or better(90%), 4 teeth good(8%), 1 tooth bad(2%). The clinical effects of composite resin group showed 40 teeth best or better (80%), 6 teeth good(10%), 4 teeth bad(8%) Both successful rates were checked by χ2, P>0.05. CONCLUSION: The clinical effects of repairing residual roots and residual crowns silver amalgam or composite resin are no differece obviously.

  3. Association of Donor and Recipient Telomere Length with Clinical Outcomes following Lung Transplantation

    Science.gov (United States)

    Courtwright, Andrew M.; Fried, Sabrina; Villalba, Julian A.; Moniodis, Anna; Guleria, Indira; Wood, Isabelle; Milford, Edgar; Mallidi, Hari H.; Hunninghake, Gary M.; Raby, Benjamin A.; Agarwal, Suneet; Camp, Philip C.; Rosas, Ivan O.; Goldberg, Hilary J.; El-Chemaly, Souheil

    2016-01-01

    Background Patients with short telomere syndromes and pulmonary fibrosis have increased complications after lung transplant. However, the more general impact of donor and recipient telomere length in lung transplant has not been well characterized. Methods This was an observational cohort study of patients who received lung transplant at a single center between January 1st 2012 and January 31st 2015. Relative donor lymphocyte telomere length was measured and classified into long (third tertile) and short (other tertiles). Relative recipient lung telomere length was measured and classified into short (first tertile) and long (other tertiles). Outcome data included survival, need for modification of immunosuppression, liver or kidney injury, cytomegalovirus reactivation, and acute rejection. Results Recipient lung tissue telomere lengths were measured for 54 of the 79 patients (68.3%) who underwent transplant during the study period. Donor lymphocyte telomeres were measured for 45 (83.3%) of these recipients. Neither long donor telomere length (hazard ratio [HR] = 0.58, 95% confidence interval [CI], 0.12–2.85, p = 0.50) nor short recipient telomere length (HR = 1.01, 95% CI = 0.50–2.05, p = 0.96) were associated with adjusted survival following lung transplant. Recipients with short telomeres were less likely to have acute cellular rejection (23.5% vs. 58.8%, p = 0.02) but were not more likely to have other organ dysfunction. Conclusions In this small cohort, neither long donor lymphocyte telomeres nor short recipient lung tissue telomeres were associated with adjusted survival after lung transplantation. Larger studies are needed to confirm these findings. PMID:27589328

  4. Changes in the periodontal condition after replacement of swaged crowns by metal.

    Science.gov (United States)

    Plotniece-Baranovska, Anita; Soboleva, Una; Rogovska, Irena; Apse, Peteris

    2006-01-01

    Evidence based clinical studies have shown exact recommended design for artificial crown reconstruction with acceptable long-term results taking into an account the biological price. Previous histological and clinical studies proved that fixed prostheses might influence the periodontal condition of crowned teeth, if not all biological criteria have been considered. The aim of the present study was to assess the periodontal condition of the crowned teeth after stainless steel swaged crowns were replaced by cast metal ceramic crowns. Participants were selected at the Institute of Stomatology, Stradin's University. Selection criteria included need to replace existing swaged crowns by metal ceramic crowns for patients with absence of any systemic disease. Following symptoms of periodontal condition were examined - presence of inflammation (clinical signs, probing) and pocket depth. Assessments were carried out at four different points of time (first appointment after replacement existing swaged crowns by temporary crowns; two weeks after cementation of permanent metal ceramic restoration; after three month; after six month). Overall bleeding score "2" and "3" at the first measurement was observed in majority of study population. Bleeding scores between the 1st and the 4th measurement was significantly lower (pcrowns by metal ceramic improves gingival health and leads to better long-term prognosis for restored teeth. It is recommended that swaged crowns be replaced with more biologically friendly crowns.

  5. Comparative fracture strength analysis of Lava and Digident CAD/CAM zirconia ceramic crowns

    OpenAIRE

    Kwon, Taek-Ka; Pak, Hyun-Soon; Yang, Jae-Ho; Han, Jung-Suk; Lee, Jai-Bong; Kim, Sung-Hun; Yeo, In-Sung

    2013-01-01

    PURPOSE All-ceramic crowns are subject to fracture during function. To minimize this common clinical complication, zirconium oxide has been used as the framework for all-ceramic crowns. The aim of this study was to compare the fracture strengths of two computer-aided design/computer-aided manufacturing (CAD/CAM) zirconia crown systems: Lava and Digident. MATERIALS AND METHODS Twenty Lava CAD/CAM zirconia crowns and twenty Digident CAD/CAM zirconia crowns were fabricated. A metal die was also ...

  6. Clinical Comparison of Root Length Measurements with Electronic Apex Locator and Conventional Radiography in Mandibular Deciduous Teeth

    Directory of Open Access Journals (Sweden)

    Eskandarian T.

    2011-04-01

    Full Text Available Statement of Problem: Success in pulpectomy of deciduous teeth greatly depends on the accuracy of root length measurements which have mostly been done radiographically. However, X-ray risks and patient cooperation have usually been a challenge for the clinicians.Purpose: The clinical comparison of root length measurements with electronic apex locator and conventional radiography in 4-6 year old children's mandibular deciduous teeth was the aim of the present study.Materials and Method: In the current clinical trial, 15 mandibular molars with 60 canals in 4-6 year old patients who had the treatment plan of pulpectomy were chosen. The measured root lengths with apex locator and parallel technique radiography were evaluated with the same reference point. Data were analyzed using simple linear regression, coefficient of correlation, coefficient of variability and also graphic Bland Altman Plot.Results: The accuracy of electronic apex locator measurements in ±0/5 from apical foramen was 85%. In all cases without considering pulp situation, the difference between the two techniques was not significant.Conclusion: The electronic apex locators are recommended for root length measurements of the deciduous mandibular molars without apical resorption, disregarding the pulp status, especially when initial radiographic films are available.

  7. Clinical observation of the use of mutation type porcelain crown on the anti-bite of lateral incisor%变异式烤瓷冠修复上侧切牙反(牙合)的临床观察

    Institute of Scientific and Technical Information of China (English)

    汤雅; 陈必新

    2012-01-01

    Objective To investigate the clinical design, tooth preparation and restoration effects of the use of mutation type precious metal ceramic crowns on the anti-bite of lateral incisor. Methods We used mutation type precious metal ceramic crown to restore 30(15 cases) anti-bite of lateral incisor. Then after 6 months to 3 years follow-up.we observed the periodontal conditions of the teeth and patients' satisfaction. Results After the restoration of mutation type precious metal ceramic crown, there was no inflammation of the abutment gums.no collapse and crack of porcelain.The appearance of teeth was significantly improved.the patients had no discomfort.and the results were satisfactory. Conclusion Mutation type precious metal ceramic crown on the lateral incisor can be effective in restoring anti-bite of lateral incisor,improving the appearance.and can be used as an alternative to orthodontic treatment.%目的:探讨运用变异式贵金属烤瓷冠修复上侧切牙反(牙合)的临床设计、牙体预备及修复效 果.方法:对30颗(15例)上侧切牙反(牙合)采用变异式贵金属烤瓷冠进行修复,修复后经6个月~3年随访,观察修复后牙周情况和患者满意度 .结果:变异式贵金属烤瓷冠修复后,基牙牙龈无明显炎症,无崩瓷、瓷裂发生,前牙美观程度明显改善,患者无不适,效果满意. 结论:变异式贵金属烤瓷冠可以有效纠正上侧切牙反(牙合),改善美观,可作为正畸治疗的替代手段.

  8. Comparative fracture strength analysis of Lava and Digident CAD/CAM zirconia ceramic crowns

    Science.gov (United States)

    Kwon, Taek-Ka; Pak, Hyun-Soon; Han, Jung-Suk; Lee, Jai-Bong; Kim, Sung-Hun

    2013-01-01

    PURPOSE All-ceramic crowns are subject to fracture during function. To minimize this common clinical complication, zirconium oxide has been used as the framework for all-ceramic crowns. The aim of this study was to compare the fracture strengths of two computer-aided design/computer-aided manufacturing (CAD/CAM) zirconia crown systems: Lava and Digident. MATERIALS AND METHODS Twenty Lava CAD/CAM zirconia crowns and twenty Digident CAD/CAM zirconia crowns were fabricated. A metal die was also duplicated from the original prepared tooth for fracture testing. A universal testing machine was used to determine the fracture strength of the crowns. RESULTS The mean fracture strengths were as follows: 54.9 ± 15.6 N for the Lava CAD/CAM zirconia crowns and 87.0 ± 16.0 N for the Digident CAD/CAM zirconia crowns. The difference between the mean fracture strengths of the Lava and Digident crowns was statistically significant (P<.001). Lava CAD/CAM zirconia crowns showed a complete fracture of both the veneering porcelain and the core whereas the Digident CAD/CAM zirconia crowns showed fracture only of the veneering porcelain. CONCLUSION The fracture strengths of CAD/CAM zirconia crowns differ depending on the compatibility of the core material and the veneering porcelain. PMID:23755332

  9. Oplevelseskommunikation hos Danish Crown

    OpenAIRE

    Mosbæk, Malene; Ralph Vogelius, Christina; Tranberg-Hansen, Morten Sejer; Møller Bøttiger, Jakob; Axelsen, Lykke Vils

    2011-01-01

    With this report we wish to discover the meaning and use of the phrase experience communication. To investigate experience communication in action, we teamed up with Danish Crown who within recent years has used experience communication as part of their communication strategy. Based on experience communication theory and empirical studies we made an analysis of their campaign “Vi ses i køkkenet”. Our report demonstrates that experiences are a useful way of communicating. Participants co...

  10. The relationship between trinucleotide (GAA) repeat length and clinical features in Friedreich ataxia

    Energy Technology Data Exchange (ETDEWEB)

    Filla, A.; De Michele, G.; Cavalcanti, F. [Federico II Univ., Naples (Italy)] [and others

    1996-09-01

    Friedreich ataxia (FA) is associated with the expansion of a GAA trinucleotide repeat in the first intron of the X25 gene. We found both alleles expanded in 67 FA patients from 48 Italian families. Five patients from three families were compound heterozygotes with expansion on one allele and an isoleucine{r_arrow}phenylalanine change at position 154 on the other one. We found neither expansions nor point mutations in three patients. The length of FA alleles ranged from 201 to 1,186 repeat units, with no overlap with the normal range, and showed a negatively skewed distribution with a peak between 800 and 1,000 repeats. The FA repeat showed meiotic instability with a median variation of 150 repeats. The lengths of both larger and smaller alleles in each patient inversely correlated with age at onset of the disorder. Smaller alleles showed the best correlation, accounting for {approximately}50% of the variation of age at onset. Mean allele length was significantly higher in patients with diabetes and in those with cardiomyopathy. 16 refs., 3 figs., 1 tab.

  11. Wear of metal-free resin composite crowns after three years in service.

    Science.gov (United States)

    Zenthöfer, Andreas; Rammelsberg, Peter; Schmitt, Clemens; Ohlmann, Brigitte

    2013-01-01

    To compare differences between the wear behavior of two types of metal-free resin composite crown with a control after three years in clinical service. Sixty-six participants needing one to three posterior single crowns were fitted with 120 crowns. Abutment teeth were randomly assigned to three groups: 40 resin composite crowns with fiber-reinforced framework, 40 resin composite crowns without fiber-reinforced framework, and 40 metal-ceramic crowns. To assess wear, gypsum replicas of the crowns were fabricated and scanned with a 3D laser scanner at baseline and after three years. Differences between the groups were analyzed by use of mixed-effects regression models. Wear of resin composite crowns with fiber-reinforced framework (p=0.0043) and resin composite crowns without framework (p=0.0246) was significantly greater than in the metal-ceramic group. Wear of metal-free resin composite crowns after three years was significantly greater than that of metal-ceramic crowns, but the wear was still clinically acceptable.

  12. Cementing porcelain-fused-to-metal crowns.

    Science.gov (United States)

    Vadachkoria, D

    2009-12-01

    The clinical success of fixed prosthodontic restorations can be complex and involve multifaceted procedures. Preparation design, oral hygiene/micro flora, mechanical forces, and restorative materials are only a few of the factors which contribute to overall success. One key factor to success is choosing the proper cement. Popular use of cements for PFM crowns has shifted from zinc phosphate and glass ionomer cements to resin-reinforced glass ionomer, or RRGI, cements. This change has been rapid and profound. Dental cements have always been less than ideal materials, but this is shift to the relatively new RRGI category justified. Resin-reinforced glass ionomer (RRGI) cements appear to be better than zinc phosphate and glass ionomer cements when placing porcelain-to-metal crowns. RRGI cements, such as RelyX Luting, Fuji Plus and Vitremer Luting Cement, satisfy more of the ideal characteristics of PFM cementation than any other previous cement. Expansion of all three cements has not caused any apparent problems with the cements when used with PFM or metal crowns, but these cements, however, should be avoided when cementing all-ceramic crowns. PMID:20090144

  13. Impact of stent length on clinical outcomes of first-generation and new-generation drug-eluting stents.

    Science.gov (United States)

    Konishi, Hirokazu; Miyauchi, Katsumi; Dohi, Tomotaka; Tsuboi, Shuta; Ogita, Manabu; Naito, Ryo; Kasai, Takatoshi; Tamura, Hiroshi; Okazaki, Shinya; Isoda, Kikuo; Daida, Hiroyuki

    2016-04-01

    The aim of this study is to compare first- and new-generation drug-eluting stents (DESs) which are implanted in long lesion. Stent length is known to be a predictor of adverse events after percutaneous coronary intervention (PCI), even with the first-generation DESs. The introduction of new-generation DESs has reduced the rates of adverse clinical events. However, the impact of stent length on long-term clinical outcomes is not well known. A total of 1181 consecutive patients who underwent PCI using either a first-generation DES (n = 885) or a new-generation DES (n = 296) between 2004 and 2011 were investigated. In each of the stent groups, the patients were divided into two groups by stent length (>32 and ≤32 mm) and compared. During the follow-up period, the incidence of major adverse cardiac events (MACEs) was significantly higher for patients with long stents implanted than with short stents (P stent groups in the new-generation DES group (P = 0.24; log-rank test). On multivariate Cox regression analysis, stent length was not associated with adverse events in the new-generation DES groups [hazard ratio (HR) 0.87; 95 % confidence interval (95 % CI) 0.71-1.04; P = 0.14]. Implanted stent length was significantly associated with a higher risk of MACEs in patients who received first-generation DESs, but not in patients who received the new-generation DESs.

  14. Infant bone age estimation based on fibular shaft length: model development and clinical validation

    International Nuclear Information System (INIS)

    Bone age in infants (<1 year old) is generally estimated using hand/wrist or knee radiographs, or by counting ossification centers. The accuracy and reproducibility of these techniques are largely unknown. To develop and validate an infant bone age estimation technique using fibular shaft length and compare it to conventional methods. We retrospectively reviewed negative skeletal surveys of 247 term-born low-risk-of-abuse infants (no persistent child protection team concerns) from July 2005 to February 2013, and randomized them into two datasets: (1) model development (n = 123) and (2) model testing (n = 124). Three pediatric radiologists measured all fibular shaft lengths. An ordinary linear regression model was fitted to dataset 1, and the model was evaluated using dataset 2. Readers also estimated infant bone ages in dataset 2 using (1) the hemiskeleton method of Sontag, (2) the hemiskeleton method of Elgenmark, (3) the hand/wrist atlas of Greulich and Pyle, and (4) the knee atlas of Pyle and Hoerr. For validation, we selected lower-extremity radiographs of 114 normal infants with no suspicion of abuse. Readers measured the fibulas and also estimated bone ages using the knee atlas. Bone age estimates from the proposed method were compared to the other methods. The proposed method outperformed all other methods in accuracy and reproducibility. Its accuracy was similar for the testing and validating datasets, with root-mean-square error of 36 days and 37 days; mean absolute error of 28 days and 31 days; and error variability of 22 days and 20 days, respectively. This study provides strong support for an infant bone age estimation technique based on fibular shaft length as a more accurate alternative to conventional methods. (orig.)

  15. Infant bone age estimation based on fibular shaft length: model development and clinical validation

    Energy Technology Data Exchange (ETDEWEB)

    Tsai, Andy; Stamoulis, Catherine; Bixby, Sarah D.; Breen, Micheal A.; Connolly, Susan A.; Kleinman, Paul K. [Boston Children' s Hospital, Harvard Medical School, Department of Radiology, Boston, MA (United States)

    2016-03-15

    Bone age in infants (<1 year old) is generally estimated using hand/wrist or knee radiographs, or by counting ossification centers. The accuracy and reproducibility of these techniques are largely unknown. To develop and validate an infant bone age estimation technique using fibular shaft length and compare it to conventional methods. We retrospectively reviewed negative skeletal surveys of 247 term-born low-risk-of-abuse infants (no persistent child protection team concerns) from July 2005 to February 2013, and randomized them into two datasets: (1) model development (n = 123) and (2) model testing (n = 124). Three pediatric radiologists measured all fibular shaft lengths. An ordinary linear regression model was fitted to dataset 1, and the model was evaluated using dataset 2. Readers also estimated infant bone ages in dataset 2 using (1) the hemiskeleton method of Sontag, (2) the hemiskeleton method of Elgenmark, (3) the hand/wrist atlas of Greulich and Pyle, and (4) the knee atlas of Pyle and Hoerr. For validation, we selected lower-extremity radiographs of 114 normal infants with no suspicion of abuse. Readers measured the fibulas and also estimated bone ages using the knee atlas. Bone age estimates from the proposed method were compared to the other methods. The proposed method outperformed all other methods in accuracy and reproducibility. Its accuracy was similar for the testing and validating datasets, with root-mean-square error of 36 days and 37 days; mean absolute error of 28 days and 31 days; and error variability of 22 days and 20 days, respectively. This study provides strong support for an infant bone age estimation technique based on fibular shaft length as a more accurate alternative to conventional methods. (orig.)

  16. Vancouver Transcatheter Aortic Valve Replacement Clinical Pathway: Minimalist Approach, Standardized Care, and Discharge Criteria to Reduce Length of Stay.

    Science.gov (United States)

    Lauck, Sandra B; Wood, David A; Baumbusch, Jennifer; Kwon, Jae-Yung; Stub, Dion; Achtem, Leslie; Blanke, Philipp; Boone, Robert H; Cheung, Anson; Dvir, Danny; Gibson, Jennifer A; Lee, Bobby; Leipsic, Jonathan; Moss, Robert; Perlman, Gidon; Polderman, Jopie; Ramanathan, Krishnan; Ye, Jian; Webb, John G

    2016-05-01

    We describe the development, implementation, and evaluation of a standardized clinical pathway to facilitate safe discharge home at the earliest time after transfemoral transcatheter aortic valve replacement. Between May 2012 and October 2014, the Heart Team developed a clinical pathway suited to the unique requirements of transfemoral transcatheter aortic valve replacement in contemporary practice. The components included risk-stratified minimalist periprocedure approach, standardized postprocedure care with early mobilization and reconditioning, and criteria-driven discharge home. Our aim was to reduce variation in care, identify a subgroup of patients suitable for early discharge (≤48 hours), and decrease length of stay for all patients. We addressed barriers related to historical practices, complex multidisciplinary stakeholder engagement, and adoption of length of stay as a quality indicator. We retrospectively reviewed the experiences of 393 consecutive patients; 150 (38.2%) were discharged early. At baseline, early discharge patients had experienced less previous balloon aortic valvuloplasty, had higher left ventricular ejection fraction, better cognitive function, and were less frail than the standard discharge group (>48 hours). Early discharge was associated with the use of local anesthesia, implantation of balloon expandable device, avoidance of urinary catheter, and early removal of temporary pacemaker. Median length of stay was 1 day for early discharge and 3 days for other patients; 97.7% were discharged home. There were no differences in 30-day mortality (1.3%), disabling stroke (0.8%), or readmission (10.7%). The implementation of a transcatheter aortic valve replacement clinical pathway shifted the program's approach to combine standardized processes and individual risk stratification. The Vancouver transcatheter aortic valve replacement clinical pathway requires a rigorous assessment to determine its efficacy, safety, and reproducibility. PMID

  17. [Ready-made crowns in the deciduous dentition].

    Science.gov (United States)

    Schulte, A

    1999-01-01

    The following review of the literature on "prefabricated crowns for deciduous teeth" attempts to highlight the benefits and limitations of this treatment modality. The use of prefabricated crowns is indicated in the following situations: severe destruction of the clinical crown, deep approximal cavities, bilateral approximal cavities, circumferential caries, history of root canal treatment, and need for fixed space retention. Compared to amalgam restorations involving two or more surfaces, prefabricated crowns on deciduous molar teeth gave very high survival rates. They consist of a chromium-nickel-steel alloy and are reported to have an acceptable gingival tolerance profile. In contrast to the Anglo-American countries this treatment modality is quite uncommon in Germany. A probable reason for this reservation could be that many clinicians often fail to see the need for a filling in the deciduous dentition. Besides, many dentists are reluctant to use local anesthesia in children, which is inevitable in preparing and fitting a prefabricated crown. In the United States and UK dentists are less frequently confronted with this problem, as complex treatments are often carried out under nitrous oxide sedation or insufflation anesthesia. Modern filling materials have been introduced which have the potential to narrow the indications for prefabricated stainless steel crowns. Against this background, future studies are necessary to compare the survival rates of prefabricated crowns and modern filling materials.

  18. Marginal Assessment of Crowns by the Aid of Parallel Radiography

    Directory of Open Access Journals (Sweden)

    Farnaz Fattahi

    2015-03-01

    Full Text Available Introduction: Marginal adaptation is the most critical item in long-term prognosis of single crowns. This study aimed to assess the marginal quality as well asthe discrepancies in marginal integrity of some PFM single crowns of posterior teeth by employing parallel radiography in Shiraz Dental School, Shiraz, Iran. Methods: In this descriptive study, parallel radiographies were taken from 200 fabricated PFM single crowns of posterior teeth after cementation and before discharging the patient. To calculate the magnification of the images, a metallic sphere with the thickness of 4 mm was placed in the direction of the crown margin on the occlusal surface. Thereafter, the horizontal and vertical space between the crown margins, the margin of preparations and also the vertical space between the crown margin and the bone crest were measured by using digital radiological software. Results: Analysis of data by descriptive statistics revealed that 75.5% and 60% of the cases had more than the acceptable space (50µm in the vertical (130±20µm and horizontal (90±15µm dimensions, respectively. Moreover, 85% of patients were found to have either horizontal or vertical gap. In 77% of cases, the margins of crowns invaded the biologic width in the mesial and 70% in distal surfaces. Conclusion: Parallel radiography can be expedient in the stage of framework try-in to yield some important information that cannot be obtained by routine clinical evaluations and may improve the treatment prognosis

  19. Effect of interprofessional clinical education programme length on students' attitudes towards teamwork.

    Science.gov (United States)

    Renschler, Lauren; Rhodes, Darson; Cox, Carol

    2016-05-01

    This article reports on a study involving a range of health professions students who participated in similar one-semester (short) or two-semester (long) interprofessional clinical education programmes that focused on clinical assessment of senior citizens living independently in the community. Students' attitudes towards teamwork skills and perceptions of their own teamwork skills both before and after the programmes were assessed using two validated scales. Osteopathic medical student participants reported no significant changes in attitudes towards interprofessional healthcare teamwork skills or their perceptions of their own interprofessional teamwork skills after either the one- or two-semester programmes. For athletic training, speech-language pathology, exercise sciences, public health, and nursing students, though, attitudes towards teamwork skills significantly improved (p attitude change, but with a significant difference between medical as compared to nursing, allied health, and public health students. PMID:27152538

  20. Effect of interprofessional clinical education programme length on students' attitudes towards teamwork.

    Science.gov (United States)

    Renschler, Lauren; Rhodes, Darson; Cox, Carol

    2016-05-01

    This article reports on a study involving a range of health professions students who participated in similar one-semester (short) or two-semester (long) interprofessional clinical education programmes that focused on clinical assessment of senior citizens living independently in the community. Students' attitudes towards teamwork skills and perceptions of their own teamwork skills both before and after the programmes were assessed using two validated scales. Osteopathic medical student participants reported no significant changes in attitudes towards interprofessional healthcare teamwork skills or their perceptions of their own interprofessional teamwork skills after either the one- or two-semester programmes. For athletic training, speech-language pathology, exercise sciences, public health, and nursing students, though, attitudes towards teamwork skills significantly improved (p teamwork attitude change, but with a significant difference between medical as compared to nursing, allied health, and public health students.

  1. 氧化铝渗透陶瓷全冠色差可接受性的临床评价%Clinical assessment of acceptability of shade mismatch of infiltrated alumina ceramic crowns

    Institute of Scientific and Technical Information of China (English)

    董正杰; 徐侃

    2011-01-01

    PURPOSE: To measure and evaluate the acceptability of shade mismatch of infiltrated alumina ceramic crowns directly in clinic. METHODS: Ten cases with restoration of hot casting alumina ceramic crown were collected in clinic. L*, a*, b*, C, H, ΔE values of hot casting alumina ceramic crowns and corresponding natural teeth in natural light were surveyed and calculated,then analyzed with CIE1976L*a*h* color system, digital photography and Photoshop CS2.All statistical analyses and calculations were completed in paired t test with SAS6.12 software package. RESULTS: In cervical 1/3 region, significant statistical difference in lightness, a*, hue angle parameter value between alumina allceramic crown and natural tooth (P<0.01) was found; in middle 1/3 region, significant difference in a*, b*, saturation parameter value (P<0.01) existed; in incisory 1/3 region, the parameters had no significant difference (P>0.05). To parameter ΔE, there was significant difference in every region, but it was in the acceptable range. CONCLUSIONS: The acceptability of shade mismatch is about 6 Δ E units, we can analyse the color difference between the restoration and natural teeth directly in clinic through symmetry of central incisor.%目的:测量和评价氧化铝渗透陶瓷全冠临床色差的可接受性.方法:收集10个氧化铝渗透陶瓷全冠修复病例,应用CIE1976L*a*b*颜色系统,采用数码摄影和Photoshop软件电腩处理技术,在自然光线下,对各全瓷冠及其相对称的天然牙测量、分析,计算L、a、b、C、H和△E各参数值.所得数据运用SAS6.12软件包进行配对t检验.结果:在颈1/3区域,氧化铝渗透陶瓷全冠和天然牙在明度、a色品值、色相角上有显著差异;在中1/3区域,参数a、b色品值和饱和度有显著差异:在切1/3区域,各参数值均无显著差异.参数△E值在各区域都有显著差异,但其差异值在患者可接受范围内.结论:氧化铝渗透陶瓷全冠色差可接受

  2. Preformed posterior stainless steel crowns: an update.

    Science.gov (United States)

    Croll, T P

    1999-02-01

    For almost 50 years, dentists have used stainless steel crowns for primary and permanent posterior teeth. No other type of restoration offers the convenience, low cost, durability, and reliability of such crowns when interim full-coronal coverage is required. Preformed stainless steel crowns have improved over the years. Better luting cements have been developed and different methods of crown manipulation have evolved. This article reviews stainless steel crown procedures for primary and permanent posterior teeth. Step-by-step placement of a primary molar stainless steel crown is documented and permanent molar stainless steel crown restoration is described. A method for repairing a worn-through crown also is reviewed.

  3. 全冠与高嵌体修复根管治疗后牙牙体缺损的临床观察%Clinical observation of root canal treatment after tooth body defection crown Onlays

    Institute of Scientific and Technical Information of China (English)

    韩风雷

    2014-01-01

    目的:观察磨牙经过根管治疗后对其运用全冠、高嵌体修复的效果。方法:选取经过某门诊完善根管治疗的磨牙240例分两组,每组120例,A组行全冠修复,B组行高嵌体修复,观察其修复的效果。结果:通过对A组120例磨牙的嵌体,B组120例磨牙全冠修复后2~5年随访观察,A组107颗修复成功,咀嚼功能恢复良好,6颗牙出现不同程度的松动,5颗出现牙龈萎缩,2颗因牙周炎拔除。 B组109颗修复成功,咀嚼功能恢复良好,边缘密合,仅5颗牙出现不同程度松动,4颗出现牙龈萎缩,2颗因牙周炎拔除。结论:根管治疗后全冠修复或高嵌体修复在临床上效果无明显差异,但鉴于高嵌体磨除牙体组织少,不破坏患牙与邻牙邻接关系,不涉及牙龈组织的关系等诸多优点,临床应更多推广高嵌体。%Objective:To observe the molars after root canal treatment using crowns, onlays its effects. Methods:after my root canal therapy outpatient perfect teeth 240 cases divided into two groups, 120 cases in each group, a set of rows crowns, onlays a row repair, repair observed effects. Results:A group of 120 cases of molar inlays, group B 120 cases molar crown after 2 to 5 years of follow-up observation repair, A group of 107 successful repair, restore chewing function well, six different degrees of loose teeth, 5 gum recession occurs, two pull out due to periodontitis. Group B 109 teeth repair is successful, chewing can be a good recovery, edge seal, only five different degrees loose teeth, gum recession occurs four, two pull out due to periodontitis.Conclusion:The root canal treatment crowns or on-lays on the clinical effect was no significant difference, but given onlays wear less tooth structure removed, does not destroy the teeth adjacent relationship with adjacent teeth, gum tissue does not involve many advantages relations, which is worthy of more clinical promotion.

  4. 纤维桩用于后牙桩核冠修复的临床疗效评价%Evaluation of the clinical effects of fiber post on the restoration of post core crown in posterior teeth

    Institute of Scientific and Technical Information of China (English)

    贾燕; 李萍

    2015-01-01

    目的 探讨纤维桩用于后牙牙体严重缺损桩核冠修复的临床效果.方法 随机选取2010年1月至2011年4月我院牙科门诊接诊的84例后牙桩核冠修复患者,采用随机数字表法,将患者分成实验组和对照组各42例,实验组采用纤维桩核冠修复,对照组采用金属桩核冠修复,对修复后第6个月和12个月的修复效果采用X线根尖片进行复查评估,对2组的临床效果进行统计学分析.结果 2组在修复后6个月和12个月的修复体边缘适合性、解剖外形、表面、X线根尖评估均为"好",其中实验组在2个时间点分别有1例出现牙龈健康状况评估为"可接受",第12个月有1例评估为"不可接受".实验组的修复成功率为95.83%,仅有2例出现桩冠松动或脱落,对照组修复成功率为81.81%,实验组的修复成功率显著高于对照组(P<0.05).结论 纤维桩用于后牙牙体严重缺损桩核冠修复的临床效果显著优于金属桩核,修复成功率更高,值得临床应用推广.%Objective To explore the clinical effects of fiber post on the restoration of posterior teeth with severe defects. Methods 84 cases of posterior teeth with severe defects randomly selected from January 2010 to 2011 April in our hospital out-patient admissions, were randomly divided into experimental group and control group with 42 cases in each group. The experimental group was restored with fiber post core crown, and the control group was restored with metal post core crown. The clinical effects of two kinds of fiber posts were compared by statistical analysis. At 6 months and 12 months after restoration, the clinical effects were assessed by X-ray peri-apical films. Results The marginal fit, anatomical shape, surface and periapical lesion by X-ray measurement of two groups were"good". In the experimental group, both at 6 months and 12 months, there was respectively 1 case evaluated by gingival health assessment as"acceptable", while there was 1 case

  5. Comparison of standardized clinical evaluation of wounds using ruler length by width and Scout length by width measure and Scout perimeter trace.

    Science.gov (United States)

    Langemo, Diane; Spahn, James; Spahn, Thomas; Pinnamaneni, V Chowdry

    2015-03-01

    The study objective was to examine precision in wound measurement using a recently Food and Drug Administration-approved Scout (WoundVision, LLC, Indianapolis, Indiana) device to measure wound length (L) and width (W). Wound perimeter and a ruler measurement of L and W were also made. Images of 40 actual patient wounds were measured using the Scout device. All 3 techniques (length, width, perimeter) demonstrated acceptable within and between reader precision; however, the best precision was in wound perimeter measurement. PMID:25679463

  6. Protein abundance of clinically relevant multidrug transporters along the entire length of the human intestine.

    Science.gov (United States)

    Drozdzik, Marek; Gröer, Christian; Penski, Jette; Lapczuk, Joanna; Ostrowski, Marek; Lai, Yurong; Prasad, Bhagwat; Unadkat, Jashvant D; Siegmund, Werner; Oswald, Stefan

    2014-10-01

    Intestinal transporters are crucial determinants in the oral absorption of many drugs. We therefore studied the mRNA expression (N = 33) and absolute protein content (N = 10) of clinically relevant transporters in healthy epithelium of the duodenum, the proximal and distal jejunum and ileum, and the ascending, transversal, descending, and sigmoidal colon of six organ donors (24-54 years). In the small intestine, the abundance of nearly all studied proteins ranged between 0.2 and 1.6 pmol/mg with the exception of those of OCT3 (intestinal segment. ABCB1, ABCG2, PEPT1, and ASBT were significantly more abundant in jejunum and ileum than in colon. In contrast to this, the level of expression of ABCC2, ABCC3, and OCT3 was found to be highest in colon. Site-dependent differences in the levels of gene and protein expression were observed for ABCB1 and ASBT. Significant correlations between mRNA and protein levels have been found for ABCG2, ASBT, OCT3, and PEPT1 in the small intestine. Our data provide further physiological pieces of the puzzle required to predict intestinal drug absorption in humans.

  7. Aesthetic treatment on anterior teeth crown fracture caused by dental trauma

    OpenAIRE

    Nanik Zubaidah

    2012-01-01

    Background: Complicated crown fracture is a tooth fracture that involve enamel, dentine and pulp. The incidence of complicated crown fracture ranges from 2% to 13% of all dental injuries and the most commonly involved teeth are the maxillary central incisors. Various treatment modalities are available depending on the clinical, physiological and radiographic examination of the involved teeth. Purpose: The aim of this case report is to present the management of crown fractures with pulpal expo...

  8. CD4+ T-lymphocyte telomere length is related to fibrosis stage, clinical outcome and treatment response in chronic hepatitis C virus infection.

    OpenAIRE

    FLETCHER, JEAN

    2010-01-01

    PUBLISHED BACKGROUND & AIMS: Increasing age is associated with impaired immune function and in chronic HCV infection specifically, with progressive fibrosis, liver failure, HCC and impaired responses to antiviral therapy. T-lymphocyte telomere length declines with age. We hypothesised that shorter T-lymphocyte telomere length would be associated with poor clinical outcome in HCV infection. METHODS: Circulating T-lymphocyte telomere length, an objective measure of immune senescence, was...

  9. Profile根管器械治疗后牙残根残冠的观察%Clinical observation of Profile machine with root canal instrumentation in treatment of posterior residual root and crown

    Institute of Scientific and Technical Information of China (English)

    陈永吉; 郭俊兵; 贺维; 毛敏; 柴红波

    2011-01-01

    目的 比较Profile机用根管器械和传统根管器械进行后牙残根残冠根管治疗的疗效,为临床治疗此类牙体疾病提供参考.方法 临床后牙残根残冠100例,随机数字表法分为治疗组(A组)50例采用Profil.机用根管器械机扩,对照组(B组)50例采用手用器械(K锉)手扩.比较两组间临床成功率、治疗时间和患者满意度.结果 对于弯曲根管,Profile机扩比手扩成功率高;对于普通根管,Profile机扩与手扩成功率无差别.但用Profile机扩技术比K锉手扩降低了患者的疼痛程度,缩短了治疗时间.结论 使用Profile机用根管器械机扩技术治疗后牙残根残冠,特别是对于弯曲根管,能够满足临床需要;同时可以提高患者满意度和缩短治疗时间.%Objective To compare the effect of Profile machine of endodontic instruments and traditional root canal instruments for residual root and crown of posterior tooth root canal treatment, for the clinical treatment of this kind of dental disease to provide reference. Methods Clinical posterior residual crown and root of 100 cases were randomly divided into two groups. Treatment group (A group) were 50 cases of teeth, including root canal curvature in 28 cases, using Profile machine root canal instruments machine. Control group(B group) were 50 cases, including 26 cases of root canal curvature , with hand instruments ( K file) hand extended, statistical its clinical success rate, treatment time, and patient satisfaction. Results For the curved root canal, Profile machine expansion endodontic instruments than hand instruments(K filing) handextended high success rate; For normal root canal, the use of machine Profile machine expansion endodontic instruments and hand instruments ( K filing) hand no difference in success rate of expansion. But the machine used Profile root canal instruments machine expansion technology than hand instruments(K file) hand extended reduces patient pain, shorten the treatment

  10. Delineation of Campylobacter concisus genomospecies by amplified fragment length polymorphism analysis and correlation of results with clinical data

    DEFF Research Database (Denmark)

    Aabenhus, R.; On, Stephen L.W.; Siemer, Berit L.;

    2005-01-01

    phenotypically indistinguishable but genetically distinct taxa (i.e., genornospecies) that may vary in pathogenicity. We examined 62 C concisus strains by amplified fragment length polymorphism (AFLP) profiling and correlated the results with clinical data. All C. concisus strains gave unique AFLP profiles......, and numerical analysis of these data distributed the strains among four clusters. The clustering was of taxonomic significance: two clusters contained, respectively, the type strain (of oral origin) and a reference strain (from diarrhea) of each of the known genomospecies. Genomospecies 2 strains were more....... All genomospecies 4 strains were of the same protein profile group and failed to react with a C concisus species-specific PCR assay based on 23S rRNA gene sequences: the taxonomic position of this group requires closer investigation. Campylobacter concisus is genetically and taxonomically diverse...

  11. Investigating the effect of clinical governess approach on patients' length of stay in emergency department: an action research study.

    Directory of Open Access Journals (Sweden)

    Tahmine Salehi

    2014-02-01

    Full Text Available Over the past decade, clinical governance approach with aims to improve the quality of health services has been proposed in Iran. Considering the obvious problems especially patients' length of stay (LOS in the emergency departments (EDs; the present study has been carried out with the purpose of Investigating the effect of clinical governess approach on patients' LOS in the one of the largest medical centers in the country. After the problem was specified by the 17 interviews with employees and managers of the ED; the emergency clinical governance committee was formed by two academic researchers and seven ED staff (key participants that had the most involvement with the subject of study. The activities of the committee, including planning, acting, observing and reflecting, was organized by using participatory action research approach and action research cycle (Kemmis 1995. During this time, three formal meetings with key participants were held in 6-month intervals. Monthly records of patients' average LOS and interview with ED staff were used to analyze the findings. The research was completed with two cycles in one year. Committee members took the following actions. As a result, the patients' LOS reduced from 2.68 days to 1.73 days. Make regular patients visits by medical groups especially orthopedists and neurologists; Decision making about patients situation by emergency physicians and transferring patients to the relevant units by bed managers; Refusing to admit elective patients during overcrowding times; to regulate the list of patients requiring ICU by anesthesiologists. Prolonged LOS can be due to various causes and a team approach, which is one of the requirements of clinical governance approach, is needed to manage it. The results showed that the multidisciplinary team could make positive changes and reduce LOS in emergency setting.

  12. Evaluation of marginal circumference and marginal thickness changes in precrimped stainless steel crowns, after recrimping

    Directory of Open Access Journals (Sweden)

    Afshar H

    2006-07-01

    Full Text Available Background and Aim: The need for recrimping precrimped stainless steel crowns by the dentist in clinic is controversial. This study aimed to evaluate the rate of marginal circumference and marginal thickness change of precrimped stainless steel crowns after recrimping. Materials and Methods: In this experimental study, 30 primary photos were taken from margins of 30 S.S.Cs (3M, Ni-Cr related to tooth 85 with a digital camera fixed at a determined distance. Margins of crowns were crimped by 114 and 137 pliers with a controlled force (0.2 N and then 30 secondary photos were taken in the same conditions. The circumference of crown margins in primary (group A and secondary (group B photos were assessed by a digitizer system. Comparing the circumferences of crown margins in primary and secondary photos showed a significant decrease after crimping. Thickness of 30 random points on the crown margins of a crown similar to mentioned cases was measured by SEM (×150. Then similar procedures including taking a primary photo, crimping and taking a secondary photo was done for the sample crown. After significant reduction in margin circumference, thickness of 30 other random points on the crown margin were measured by SEM. Data were analyzed by paired sample t-test with p<0.05 as the limit of significance. Results: The mean marginal circumference of precrimped stainless steel crowns was reduced by 7.3% which was significant (P<0.001. On the other hand the mean marginal thickness of sample stainless steel crown showed 18µ increase. Conclusion: According to the results of this study, marginal circumference of precrimped stainless steel crowns (3M, Ni-Cr showed a significant decrease after crimping. It is concluded that crimping the stainless steel crowns even for precrimped ones seems necessary.

  13. Laser-assisted flapless crown lengthening: a case series.

    Science.gov (United States)

    McGuire, Michael K; Scheyer, E Todd

    2011-01-01

    As part of the paradigm shift toward more minimally invasive surgical procedures, increasing numbers of references to laser-mediated flapless crown lengthening are noted in the published literature. The vast majority of these references are noncontrolled case reports or technique-focused articles. Therefore, prospective, randomized controlled studies that objectively examine the safety and efficacy of flapless crown lengthening are lacking. The current case series represents an initial attempt to examine some of the clinical issues posed by this minimally invasive flapless approach. Ultimately, only well-designed controlled clinical trials can yield the type of evidence-based data necessary to categorize this approach to crown lengthening as standard-of-care treatment.

  14. 单个前牙种植体修复——五年的临床观察与分析%Clinical Study of Implant Supported Single Incisor Crown

    Institute of Scientific and Technical Information of China (English)

    石连水; 周汝俊; 朱玉芬

    2001-01-01

    目的:对比分析单个前牙种植体的传统临时冠修复和即刻烤瓷冠修复的临床效果。方法:对1992年10月至1995年5月的我院共39例2组前牙种植患者,采用临床四级评分的半定量方法,观察5年后评估两种修复方法的临床效果。结果:即刻烤瓷冠修复的临床效果明显优于临时冠修复。结论:即刻烤瓷冠修复单个前牙种植体是一种切实可行的方法。%To study the clinical effects of prosthesis in immediatd implant at singe anodontia incisor compared with traditional temporary resin veneer crown. Methods: Four level half-quantitative evaluations were to study two group patients with different kinds of prosthesis. Result: Study showed that there was a significant difference between the two kinds of prosthesis on success rats of dental implant. Conclusion: The prosthesis of incisor immediate implant is practical and effective.

  15. 不同材质桩核冠在前牙美学区修复的临床研究%The clinical study of restoration for anterior aesthetic zone with different material post and core crown

    Institute of Scientific and Technical Information of China (English)

    李慧; 崔广; 伍小臻; 宫琳

    2013-01-01

    Objective To observe the clinical effect of glass fiber pile combined with all-ceramic crown in restoration for dental defects of anterior aesthetic zone compared with cast metal post-core combined with cobalt-chromium PFM crown. Methods The present investigation enrolled 100 patients (150 teeth) who had been treated for dental defects of anterior aesthetic zone. According to the patient's request, they were divided into two groups. After root canal therapy, Group A(50 patients, 70 teeth) was treated by glass fiber pile combined with all-ceramic crown. Group B(50 Patients, 80 teeth) was treated by cast metal post-core combined with cobalt-chromium PFM crown. We detected the periodontal probing depth and the alkaline phosphatase (ALP) levels in gingival crevicular fluid (GCF) in the preoperation and postoperation.We observed the fitness of prosthesis edge and the aesthetic manifestations of anterior zone. Followed up for 1 to 3 years, we observed the success rate for restoration and evaluated the long-term curative effect between two groups. Results There was statistical difference in the success rate for restoration between two groups (88.6%vs.77.5%, P0.05). The levels of ALP in GCF of group B was significantly higher than that in the preoperation (P<0.05). Conclusion Glass fiber pile combined with all-ceramic crown has relatively small stimulation on periodontium, has a good biocompatibility and aesthetics, which can be used as an ideal restoration method for anterior aesthetic restorations.%目的:观察玻璃纤维桩联合全瓷冠与铸造金属桩联合钴铬烤瓷冠在前牙美学区牙体缺损修复中的临床疗效。方法将前牙美学区牙体缺损需行桩核修复的患者100例(150颗牙),按照患者的选择意愿,分为玻璃纤维桩联合全瓷冠修复组(A组,50例70颗)和铸造金属桩联合钴铬烤瓷冠修复组(B组,50例80颗)。对修复前后牙周探诊深度、龈沟液碱性磷酸酶(ALP

  16. Clinical evaluation of selective double gingival retraction technique for anterior all-ceramic crown prosthesis%选择性双线排龈技术在前牙全瓷冠修复中的应用研究

    Institute of Scientific and Technical Information of China (English)

    刘思言; 牟雁东

    2016-01-01

    目的:评价选择性双线排龈技术在前牙全瓷冠修复中的临床应用效果。方法选择126例门诊患者258颗前牙行全瓷冠修复,简单随机法分为两组各63例,试验组130颗基牙采用选择性双线排龈技术排龈,对照组128颗采用单线排龈技术排龈,评价牙龈止血效果满意率、预备体边缘和肩台暴露、游离龈与牙面分离满意率。结果选择性双线排龈技术的牙龈止血效果满意率、预备体边缘和肩台暴露、游离龈与牙面分离满意率分别为96.92%、96.15%及95.38%,明显高于单线排龈技术的83.59%、82.03%及81.25%。差异有统计学意义( P<0.05)。结论在前牙全瓷冠修复中,选择性双线排龈技术有很好的临床应用效果。%Objective To evaluate the clinical application effect of selective double gingival retraction technique for anterior all-ceramic crown prosthesis .Methods Two hundred and fifty-eight anterior all-ceramic crowns from 126 patients were randomly divid-ed into experimental or control groups ,63 cases in each group.Selective gingival retraction technique was used in the experimental group (130 teeth) while singlet gingival retraction technique was used in the control group (128 teeth).The effect on satisfaction rates of gingival hemostasis ,prepared teeth margins and shoulder exposure ,and satisfaction rates of separation of free gingiva and tooth sur-face were evaluated .Results The rates of satisfaction of gingival hemostasis ,prepared teeth margins and shoulder exposure and separa-tion of free gingiva and tooth surface in the selective double gingival retraction group were 96.92%,96.15%and 95.38%,respective-ly,that were significantly higher than that with singlet gingival retraction technique (83.59%,82.03%and 81.25%,respectively) (P<0.05 ) .Conclusion Selective double gingival retraction technique is an effective method for anterior all -ceramic crown prosthesis .

  17. Prosthetic crowns and other clinical risk indicators of caries among old-old Swedish adults: findings from the KEOHS Project. Kungsholmen Elders Oral Health Study

    DEFF Research Database (Denmark)

    Morse, Douglas E; Holm-Pedersen, Poul; Holm-Pedersen, Jytte;

    2002-01-01

    The Kungsholmen Elders Oral Health Study (KEOHS) evaluated the oral health status of generally healthy, community-dwelling persons over the age of 80 living in Kungsholmen, Sweden. This paper explored possible clinical risk indicators of coronal and root caries among the KEOHS subjects....

  18. Release and systemic accumulation of heavy metals from preformed crowns used in restoration of primary teeth.

    Science.gov (United States)

    Kodaira, Hiroe; Ohno, Kohachiro; Fukase, Naoko; Kuroda, Midori; Adachi, Shiki; Kikuchi, Motohiro; Asada, Yoshinobu

    2013-01-01

    Preformed crowns for restoration of primary teeth are used in various treatments and are essential for restoring the crowns of primary molars. However, there are concerns that mechanical, chemical, and thermal stimulation may cause release of components of such crowns. We examined systemic accumulation of heavy metals associated with preformed crowns (3M Stainless Steel Primary Molar Crowns) used in primary tooth restoration. The participants were 37 children who had visited the Pediatric Dental Clinic of Tsurumi University Dental Hospital. They were divided into two groups: 22 participants without a history of being fitted with a preformed crown for primary tooth restoration (controls), and 15 participants with preformed crowns for primary tooth restoration. Analysis of hair samples showed a significant difference in the level of the trace element Cr - an important component of the preformed crowns - between children with and without preformed crowns, but no significant differences in Fe or Ni levels. Levels of the trace elements Ni, Cr, and Fe were within allowable ranges, indicating that these minerals were not likely to be harmful.

  19. 3D statistical failure analysis of monolithic dental ceramic crowns.

    Science.gov (United States)

    Nasrin, Sadia; Katsube, Noriko; Seghi, Robert R; Rokhlin, Stanislav I

    2016-07-01

    For adhesively retained ceramic crown of various types, it has been clinically observed that the most catastrophic failures initiate from the cement interface as a result of radial crack formation as opposed to Hertzian contact stresses originating on the occlusal surface. In this work, a 3D failure prognosis model is developed for interface initiated failures of monolithic ceramic crowns. The surface flaw distribution parameters determined by biaxial flexural tests on ceramic plates and point-to-point variations of multi-axial stress state at the intaglio surface are obtained by finite element stress analysis. They are combined on the basis of fracture mechanics based statistical failure probability model to predict failure probability of a monolithic crown subjected to single-cycle indentation load. The proposed method is verified by prior 2D axisymmetric model and experimental data. Under conditions where the crowns are completely bonded to the tooth substrate, both high flexural stress and high interfacial shear stress are shown to occur in the wall region where the crown thickness is relatively thin while high interfacial normal tensile stress distribution is observed at the margin region. Significant impact of reduced cement modulus on these stress states is shown. While the analyses are limited to single-cycle load-to-failure tests, high interfacial normal tensile stress or high interfacial shear stress may contribute to degradation of the cement bond between ceramic and dentin. In addition, the crown failure probability is shown to be controlled by high flexural stress concentrations over a small area, and the proposed method might be of some value to detect initial crown design errors. PMID:27215334

  20. Biologic width and crown lengthening: case reports and review.

    Science.gov (United States)

    Oh, Se-Lim

    2010-01-01

    The biologic width includes both the connective tissue attachment and the junctional epithelium and has a mean dimension of approximately 2 mm. Invading the biologic width with a restoration can result in localized crestal bone loss, gingival recession, localized gingival hyperplasia, or a combination of these three. When restoring teeth that have subgingival caries or fractures below the gingival attachment, a clinical crown-lengthening procedure is needed to establish the biologic width. This article presents three case reports that utilized crown-lengthening procedures.

  1. Digital modeling technology for full dental crown tooth preparation.

    Science.gov (United States)

    Dai, Ning; Zhong, Yicheng; Liu, Hao; Yuan, Fusong; Sun, Yuchun

    2016-04-01

    A dental defect is one of the most common oral diseases, and it often requires a full crown restoration. In this clinical operation, the dentist must manually prepare the affected tooth for the full crown so that it has a convergence angle between 4° and 10°, no undercuts, and uniform and even shoulder widths and depths using a high speed diamond bur in the patient׳s mouth within one hour, which is a difficult task that requires visual-manual operation. The quality of the tooth preparation has an important effect on the success rate of the subsequent prosthodontic treatment. This study involved research into digital modeling technology for full dental crown tooth preparation. First, the margin line of the tooth preparation was designed using a semi-automatic interactive process. Second, the inserting direction was automatically computed. Then, the characteristic parameters and the constraints on the tooth preparation were defined for the model. Next, the shoulder and axial surface of the tooth preparation were formed using parametric modeling. Finally, the implicit surface of a radial basis function was used to construct the tooth preparation׳s occlusal surface. The experimental results verified that the method of digital modeling for full crown preparation proposed in this study can quickly and accurately implement personalized designs of various parameters, such as the shoulder width and the convergence angle; it provides a digital design tool for full crown preparation.

  2. Digital modeling technology for full dental crown tooth preparation.

    Science.gov (United States)

    Dai, Ning; Zhong, Yicheng; Liu, Hao; Yuan, Fusong; Sun, Yuchun

    2016-04-01

    A dental defect is one of the most common oral diseases, and it often requires a full crown restoration. In this clinical operation, the dentist must manually prepare the affected tooth for the full crown so that it has a convergence angle between 4° and 10°, no undercuts, and uniform and even shoulder widths and depths using a high speed diamond bur in the patient׳s mouth within one hour, which is a difficult task that requires visual-manual operation. The quality of the tooth preparation has an important effect on the success rate of the subsequent prosthodontic treatment. This study involved research into digital modeling technology for full dental crown tooth preparation. First, the margin line of the tooth preparation was designed using a semi-automatic interactive process. Second, the inserting direction was automatically computed. Then, the characteristic parameters and the constraints on the tooth preparation were defined for the model. Next, the shoulder and axial surface of the tooth preparation were formed using parametric modeling. Finally, the implicit surface of a radial basis function was used to construct the tooth preparation׳s occlusal surface. The experimental results verified that the method of digital modeling for full crown preparation proposed in this study can quickly and accurately implement personalized designs of various parameters, such as the shoulder width and the convergence angle; it provides a digital design tool for full crown preparation. PMID:26945598

  3. Wave Forces on Crown Walls

    DEFF Research Database (Denmark)

    Pedersen, Jan; Burcharth, H. F.

    1993-01-01

    This paper presents some of the results from a large parametric laboratory study including more than 200 long-duration model tests. The study addresses both the wave forces imposed on the breakwater crown wall as well as the performance of the structure in reducing the wave overtopping. The testing...... programme includes variations of the sea state parameters and of the geometrical configuration of the breakwater and crown wall. Basic relations between forces/overtopping and the varied parameters are examined and preliminary design guidelines for structures within the tested range of variations are...

  4. The effect of manipulating root mean square window length and overlap on reliability, inter-individual variability, statistical significance and clinical relevance of electromyograms.

    Science.gov (United States)

    Mark Burden, Adrian; Lewis, Sandra Elizabeth; Willcox, Emma

    2014-12-01

    Numerous ways exist to process raw electromyograms (EMGs). However, the effect of altering processing methods on peak and mean EMG has seldom been investigated. The aim of this study was to investigate the effect of using different root mean square (RMS) window lengths and overlaps on the amplitude, reliability and inter-individual variability of gluteus maximus EMGs recorded during the clam exercise, and on the statistical significance and clinical relevance of amplitude differences between two exercise conditions. Mean and peak RMS of 10 repetitions from 17 participants were obtained using processing window lengths of 0.01, 0.15, 0.2, 0.25 and 1 s, with no overlap and overlaps of 25, 50 and 75% of window length. The effect of manipulating window length on reliability and inter-individual variability was greater for peak EMG (coefficient of variation [CV] mean EMG (CV mean EMG was affected by manipulation of window length. Statistical significance of peak EMG was more sensitive to changes in window length, with lower p-values generally being recorded for the 1 s window. As use of different window lengths has a greater effect on variability and statistical significance of the peak EMG, then clinicians should use the mean EMG. They should also be aware that use of different numbers of exercise repetitions and participants can have a greater effect on EMG parameters than length of processing window.

  5. 钢丝结扎配合全冠修复根管治疗术后纵折牙58例临床疗效观察%Wire ligation with full crown restoration after root canal treatment longitudinal fold teeth 58 cases of clinical curative effect observation

    Institute of Scientific and Technical Information of China (English)

    张学兵; 付金华

    2015-01-01

    Objective: to observe the wire ligature with full crown restoration after root canal treatment the clinical curative effect of longitudinal fold teeth.Methods:Stainless steel wire in the champions league first eight ligation, coupled with use full crown restoration root canal treatment.Results:in all 58 patients with longitudinal fold the tooth repair, there are 56 patients effectively, effective rate was 96.6%.Conclusion:wire ligation with full crown restoration treatment teeth of vertical root canal therapy of postoperative fracture clinical curative effect, worth extending application.%目的:观察钢丝结扎配合全冠修复根管治疗术后纵折牙的临床疗效。方法先采用不锈钢丝冠内8字结扎,再配合使用全冠修复根管治疗。结果全部58例纵折牙修复患者中,有56例患者有效,有效率为96.6%。结论钢丝结扎配合全冠修复治疗根管治疗术后纵折牙的临床疗效确切,值得推广运用。

  6. Mechanical Analysis of Dead Load Crown and Structure Parameter of Hydraulic Elastic Bulging Roll

    Institute of Scientific and Technical Information of China (English)

    ZHAO Chang-cai; LI Wei-min; LIU Zhu-bai

    2003-01-01

    The dead load crown of hydraulic elastic bulging roll was discussed using the theory of elastically supported beam, and the dead load experiment was carried out. The theoretical calculation is consistent with the experimental result. The structure parameters for the thickness of roll sleeve, the length of the oil groove and the crown of roll were discussed. The fundamental principle of determining the parameters was put forward. The theoretical basis of the application of the hydraulic elastic bulging roll was established.

  7. A Simple Chairside Technique of Removing Crown and Fixed Partial Denture Restorations

    Directory of Open Access Journals (Sweden)

    Abhinav Gupta

    2014-03-01

    Full Text Available Retrieving failed cemented crowns and fixed partial dentures with minimum discomfort to the patient has always been a clinical concern. This article describes a technique which will allow easy and predictable removal of these restorations.

  8. A Simple Chairside Technique of Removing Crown and Fixed Partial Denture Restorations

    OpenAIRE

    Abhinav Gupta

    2014-01-01

    Retrieving failed cemented crowns and fixed partial dentures with minimum discomfort to the patient has always been a clinical concern. This article describes a technique which will allow easy and predictable removal of these restorations.

  9. Analysis of association among clinical features and shorter leukocyte telomere length in mitochondrial diabetes with m.3243A>G mitochondrial DNA mutation

    OpenAIRE

    Zhou, Mei-Cen; Min, Rui; Ji, Jian-Jun; Zhang, Shi; Tong, An-li; Xu, Jian-Ping; Li, Zeng-Yi; Zhang, Hua-Bing; Li, Yu-xiu

    2015-01-01

    Background Mitochondrial diabetes is a kind of rare diabetes caused by monogenic mutation in mitochondia. The study aimed to summarize the clinical phenotype profiles in mitochondrial diabetes withm.3243A>G mitochondrial DNA mutation and to investigate the mechanism in this kind of diabetes by analyzing the relationship among clinical phenotypes and peripheral leukocyte DNA telomere length. Methods Fifteen patients with maternally inherited diabetes in five families were confirmed as carrying...

  10. Earth Pressure on Tunnel Crown

    DEFF Research Database (Denmark)

    Andersen, Lars

    Two different analyses have been carried out in order to find the vertical earth pressure, or overburden pressure, at the crown of a tunnel going through a dike. Firstly, a hand calculation is performed using a simple dispersion of the stresses over depth. Secondly, the finite‐element program...

  11. Elimination of a "Gummy Smile" With Crown Lengthening and Lip Repositioning.

    Science.gov (United States)

    Mahn, Douglas H

    2016-01-01

    Excessive gingival display is considered unattractive by many patients. A combination of surgical approaches may be required to correct this problem. Clinical crown lengthening involves recontouring crestal bone levels and moving the gingival margin in an apical direction. Lip repositioning reduces gingival display by limiting upper lip movement when smiling. This article describes a case in which a combination of clinical crown lengthening and lip repositioning was used to correct excessive gingival display when smiling.

  12. Implementing a clinical pathway for hip fractures; Effects on hospital length of stay and complication rates in five hundred and twenty six patients

    NARCIS (Netherlands)

    P.T.P.W. Burgers (Paul T. P. W.); E.M.M. van Lieshout (Esther); J. Verhelst (Joost); I. Dawson (Imro); P.A.R. Rijcke (Piet)

    2014-01-01

    textabstractPurpose: Modern management of the elderly with a hip fracture is complex and costly. The aim of this study was to compare the treatment-related hospital length of stay (HLOS) before and after implementing a clinical pathway for patients undergoing hip fracture surgery. Methods: This was

  13. Reflectance signature on sunlit crown of conifers

    Institute of Scientific and Technical Information of China (English)

    王锦地; 李小文; 项月琴

    1997-01-01

    Based on the field measurements of the reflected radiation distribution on sunlit crown surface and crown structure, the analytical approximation model of path-scattering of light in a homogeneous layer is applied to the calculation of the reflectance signature of sunlit crown. The reflectance on the sunlit crown surface is considered as the weighted sum of the direct-to-hemisphere reflectance and the hemisphere-to-hemisphere reflectance. The validation results show that the calculated reflectance signature fits the field measurement very well This paper presents details of the validation and the feasibility of the model application to nonuniform medium, such as tree crown canopies.

  14. Strength and marginal fit of full and partial porcelain crowns on Brånemark implants.

    Science.gov (United States)

    Kersten, S; Tiedemann, C

    2000-02-01

    The aim of the present study was to evaluate strength and marginal fit of different designed single crowns screwed on titanium implants (Brånemark) without the usage of any abutment. Seven test groups with 10 specimens each (standardized maxillary central incisor crowns) were fabricated of Empress (staining/veneering technique), metal-based Empress (staining/veneering technique), metal-based In-Ceram and metal ceramic (with/without cervical porcelain margin). The marginal fit of 5 specimens of each group was evaluated (SEM-Analysis) and the crowns were incisally loaded at a 30 degrees angle in a Zwick testing machine until fracture. The 5 remaining specimens underwent a marginal evaluation (SEM-analyses) before and after thermo-mechanical stressing (tms) and were loaded in the Zwick testing machine as well. All Empress ceramic crowns without metal reinforcement fractured during fixing procedure on the implant (32 N cm). The gap medians of the fixed crowns ranged from 11 microns (metal ceramic crowns) to 34 microns (metal ceramic crowns with porcelain margin). No significant differences in gap width were observed before and after tms. In the strength analyses screw-binding forces (SBF) of about 135 N were registered in all test groups. Fracture failure forces (FFF) reached up to 280 N. The indication of the crown designs presented in this study is limited in clinical use because of low stability and esthetics.

  15. Modelling initial mortality of Abies religiosa in a crown fire in Mexico

    Directory of Open Access Journals (Sweden)

    Salomé Temiño-Villota

    2016-04-01

    Full Text Available Aim of study: The objectives of this work were to determine which morphological and fire severity variables may help explain the mortality of adult Abies religiosa (Kunth Schltdl. & Cham., to model the probability of this species after being affected by crown fire, and to obtain more elements to classify the sacred fir in terms of fire resistance. This type of studies are relevant to estimate the impact of crown fires on the climax forests that forms this species.Area of study: The burned forest was located in the southern Mexico City, borough.Material and methods: Morphological variables and fire severity indicators were collected for 335 Abies religiosa trees burned by a mixed severity fire. Logistic regression was used to analyze data and develop models that best explained tree mortality.Main results: Survival was 26.9%. The models for height (p≤0.0001, diameter at breast height (p=0.0082, crown length (p≤0.0001 and crown base height (p≤0.0001 were significant, with a negative relationship between each one of these variables and probability of mortality. The significant severity variables were lethal scorch height (p≤0.0001 and crown kill (p≤ 0.0001, which have a direct relationship with probability of mortality.Highlights: This species is moderately fire-resistant. Crown kill ≥ 70% markedly increases mortality. Silvicultural activities such as pruning, thinning and fuel management can reduce the risk of crown fires.

  16. Early complications and performance of 327 heat-pressed lithium disilicate crowns up to five years

    Science.gov (United States)

    2016-01-01

    PURPOSE The prospective follow-up aimed to assess the performance of lithium disilicate crowns and clinical reasons of adverse events compromising survival and quality. MATERIALS AND METHODS 58 patients were treated with 375 heat-pressed monolithic crowns, which were bonded with resin cement. Annual recalls up to five years included a complete dental examination as well as quality assessment using CDA-criteria. Any need for clinical intervention led to higher complication rate and any failure compromised the survival rate. Kaplan-Meier-method was applied to all crowns and a dataset containing one randomly selected crown from each patient. RESULTS Due to drop-outs, 45 patients (31 females, 14 males) with the average age of 43 years (range = 17–73) who had 327 crowns (176 anterior, 151 posterior; 203 upper jaw, 124 lower jaw) were observed and evaluated for between 4 and 51 months (median = 28). Observation revealed 4 chippings, 3 losses of retention, 3 fractures, 3 secondary caries, 1 endodontic problem, and 1 tooth fracture. Four crowns had to be removed. Survival and complication rate was estimated 98.2% and 5.4% at 24 months, and 96.8% and 7.1% at 48 months. The complication rate was significantly higher for root canal treated teeth (12%, Poral hygiene) to reach full success with these crowns. PMID:27350853

  17. Ex vivo fracture resistance of direct resin composite complete crowns with and without posts on maxillary premolars.

    NARCIS (Netherlands)

    Fokkinga, W.A.; Bell, A.M. Le; Kreulen, C.M.; Lassila, L.V.; Vallittu, P.K.; Creugers, N.H.J.

    2005-01-01

    AIM: To investigate ex vivo the fracture resistance and failure mode of direct resin composite complete crowns with and without various root canal posts made on maxillary premolars. METHODOLOGY: The clinical crowns of 40 human extracted single-rooted maxillary premolars were sectioned at the cemento

  18. Fracture behavior of structurally compromised non-vital maxillary premolars restored using experimental fiber reinforced composite crowns.

    NARCIS (Netherlands)

    Fokkinga, W.A.; Kreulen, C.M.; Bell-Ronnlof, A.M. Le; Lassila, L.V.; Vallittu, P.K.; Creugers, N.H.J.

    2006-01-01

    PURPOSE: To study the fracture behavior of direct resin composite crowns with or without experimental fiber reinforcement. METHODS: Clinical crowns of single-rooted maxillary premolars were cut off at the cemento-enamel junction. Canals were prepared with Gates Glidden drills up to size 4. No additi

  19. Evaluation of marginal circumference and marginal thickness changes in precrimped stainless steel crowns, after recrimping

    OpenAIRE

    Afshar H; Mozafari Kojidi M

    2006-01-01

    Background and Aim: The need for recrimping precrimped stainless steel crowns by the dentist in clinic is controversial. This study aimed to evaluate the rate of marginal circumference and marginal thickness change of precrimped stainless steel crowns after recrimping. Materials and Methods: In this experimental study, 30 primary photos were taken from margins of 30 S.S.Cs (3M, Ni-Cr) related to tooth 85 with a digital camera fixed at a determined distance. Margins of crowns were crimped by 1...

  20. A clinical study on ultrasonographic measurement of cervical length at 18-24 weeks of gestation and pregnancy outcome

    Directory of Open Access Journals (Sweden)

    Jayati Nath

    2016-04-01

    Conclusions: Shorter cervices lead to shorter gestations and early labour. Thus ultrasonographic measurement of cervical length at 18-24 weeks of gestation is very important, more so in asymptomatic women and can be utilized as a tool for predicting adverse pregnancy outcome especially preterm labour and delivery. [Int J Reprod Contracept Obstet Gynecol 2016; 5(4.000: 1088-1092

  1. Identification of cultured isolates of clinically important yeast species using fluorescent fragment length analysis of the amplified internally transcribed rRNA spacer 2 region

    Directory of Open Access Journals (Sweden)

    Muylaert An

    2002-07-01

    Full Text Available Abstract Background The number of patients with yeast infection has increased during the last years. Also the variety of species of clinical importance has increased. Correct species identification is often important for efficient therapy, but is currently mostly based on phenotypic features and is sometimes time-consuming and depends largely on the expertise of technicians. Therefore, we evaluated the feasibility of PCR-based amplification of the internally transcribed spacer region 2 (ITS2, followed by fragment size analysis on the ABI Prism 310 for the identification of clinically important yeasts. Results A rapid DNA-extraction method, based on simple boiling-freezing was introduced. Of the 26 species tested, 22 could be identified unambiguously by scoring the length of the ITS2-region. No distinction could be made between the species Trichosporon asteroides and T. inkin or between T. mucoides and T. ovoides. The two varieties of Cryptococcus neoformans (var. neoformans and var. gattii could be differentiated from each other due to a one bp length difference of the ITS2 fragment. The three Cryptococcus laurentii isolates were split into two groups according to their ITS2-fragment lengths, in correspondence with the phylogenetic groups described previously. Since the obtained fragment lengths compare well to those described previously and could be exchanged between two laboratories, an internationally usable library of ITS2 fragment lengths can be constructed. Conclusions The existing ITS2 size based library enables identification of most of the clinically important yeast species within 6 hours starting from a single colony and can be easily updated when new species are described. Data can be exchanged between laboratories.

  2. Relationships of Chamaecyparis formosensis crown shape and parameters with thinning intensity and age

    Directory of Open Access Journals (Sweden)

    Tian-Ming Yen

    2015-12-01

    Full Text Available Taiwan red cypress (Chamaecyparis formosensis Matsum is an indigenousand important cypress conifer with a broad area of natural forests and plantations in Taiwan. Because of the high economic value and multiple uses of the species, numerous researchers have studied its growth and yield within plantation forests. However, few studies have examined how the crown characteristics of the tree respond to different thinning regimes, particularly in the long run. The crown is a dominant outline of aboveground component of a tree that can sensitively reflect competitions from trees located nearby. This study evaluated the crown form of Taiwan red cypress at three different growth stages with different thinning intensities over 20 years. The study began in 1982, when the three plantations examined were aged 7, 15, and 21 years, and when thinning treatments began. In 2002, crown form parameters (CFPs and crown profile equations (CPEs were used to analyze the thinning effects at the tree level. Two-way analysis of variance (ANOVA revealed that age class influenced most CFPs and that thinning treatments influenced all CFPs, indicating that both factors could simultaneously affect the CFPs. Moreover, the CPEs fit the observed data well for all age classes, demonstrating that the equation had a high capacity for predicting crown form. The CPEs were used to determine the mean crown shape profile for each thinning treatment and age class. According to the mean crown profile predicted by CPEs, we found that crown length and width increased with thinning intensity for all aged trees, especially after a heavy thinning treatment.

  3. Genetic Diversity of Trichomonas vaginalis Clinical Isolates Determined by EcoRI Restriction Fragment Length Polymorphism of Heat-Shock Protein 70 Genes

    OpenAIRE

    Meade, John C.; de Mestral, Jacqueline; Jonathan K Stiles; Secor, W. Evan; Finley, Richard W.; Cleary, John D.; Lushbaugh, William B.

    2009-01-01

    Restriction fragment length polymorphism (RFLP) analysis using a multilocus heat-inducible cytoplasmic heat-shock protein 70 (Hsp70) hybridization probe with EcoRI-digested genomic DNA was used in molecular typing of 129 Trichomonas vaginalis isolates. Results indicate that Trichomonas organisms exhibit considerable polymorphism in their Hsp70 RFLP patterns. Analysis of seven American Type Culture Collection reference strains and 122 clinical isolates, including 84 isolates from Jackson, Miss...

  4. Pemakaian Crown Loop dan Band Loop di Rahang Bawah Anak Usia Enam Tahun (Laporan Kasus

    Directory of Open Access Journals (Sweden)

    Rivi Isabela

    2015-11-01

    Full Text Available The function of space maintainer is to preserve arch length following the premature loss of a primary teeth. Early loss of primary tooth may compromise the eruption of succedaneous teeth if there is a reduction in the arch length. The Band and Crown Loop are used to maintain the loss of primary molar. The report describe a 6 year old girl who has premature loss of second left mandibular primary molar and first right mandibular primary molar treated using crown and band loop space maintainer. The patient still has mastication function from other posterior primary teeth.

  5. Marginal accuracy of temporary composite crowns.

    Science.gov (United States)

    Tjan, A H; Tjan, A H; Grant, B E

    1987-10-01

    An in vitro study was conducted to quantitatively compare the marginal adaptation of temporary crowns made from Protemp material with those made from Scutan, Provisional, and Trim materials. A direct technique was used to make temporary restorations on prepared teeth with an impression as a matrix. Protem, Trim, and Provisional materials produced temporary crowns of comparable accuracy. Crowns made from Scutan material had open margins. PMID:2959770

  6. Crown lengthening to facilitate restorative treatment in the presence of incomplete passive eruption.

    Science.gov (United States)

    Hempton, T J; Esrason, F

    2000-04-01

    Crown-lengthening surgery can be utilized to expose subgingival caries. In this clinical case, a patient presented with incomplete passive eruption in the maxillary anterior sextant. This case illustrates that when incomplete passive eruption is present and restorative treatment is necessary in the maxillary anterior sextant, crown-lengthening surgery not only provides exposure of subgingival caries but can also result in a more esthetic therapeutic outcome.

  7. Full mouth rehabilitation of partially and fully edentulous patient with crown lengthening procedure: a case report

    OpenAIRE

    Seol, Hyon-Woo; Koak, Jai-Young; Kim, Seong-Kyun; Heo, Seong-Joo

    2010-01-01

    BACKGROUND In order to restore severely attrited teeth properly, surgical intervention in the form of a crown-lengthening procedure may be required. And also, proper diagnosis and treatment sequencing is critical to obtain a successful results. Adequate diagnostic wax-up ensures good esthetics and healthy periodontal tissue. CASE DESCRIPTION This clinical case report describes a diagnostically based protocol for restoration on mandibular anterior teeth with crown lengthening procedure and the...

  8. Avaliação das condutas adotadas por profissionais na utilização de coroas metalo-cerâmicas Assessment of clinical proceedings adopted by dental professionals regarding the employment of ceramic fused to metal crowns

    Directory of Open Access Journals (Sweden)

    Carlos Neanes Santos

    2003-12-01

    Full Text Available A fim de avaliar a opinião da classe odontológica sobre a utilização das coroas metalo-cerâmicas na prática odontológica, aplicou-se um questionário de 20 questões a cirurgiões-dentistas da cidade de Aracaju - SE, e a cirurgiões-dentistas e estudantes de pós-graduação em odontologia, na área de prótese dental, da cidade de Bauru-SP. Concluiu-se que: 1. As coroas metalo-cerâmicas são o tipo de restauração protética mais empregado em Odontologia. 2. A maioria dos dentistas refere-se às coroas metalo-cerâmicas como restaurações bem sucedidas, indicando superfícies oclusais metálicas para a maioria dos pacientes. 3. Apesar da maior parte dos profissionais utilizar as ligas de níquel-cromo nas coroas metalo-cerâmicas de seus pacientes, os mesmos prefeririam que ligas nobres ou semi-nobres fossem empregadas em suas próprias restaurações. 4. A maioria dos entrevistados emprega as coroas metalo-cerâmicas na restauração de dentes anteriores (57,23%. Entretanto, esse valor se deve à preferência dos dentistas de Aracaju (78% por esse tipo de restauração, ao passo que, em Bauru, prevaleceu o número de respostas favoráveis às coroas de porcelana pura. 5. O cimento de fosfato de zinco foi o cimento de escolha da maioria dos profissionais. 6. A preferência da maior parte dos entrevistados, com relação à porcelana utilizada foi pela porcelana Vita (34,34%, em comparação às porcelanas Noritake e Dulceram Plus (13,86%. 6. Ficou evidente o desejo dos entrevistados quanto ao desenvolvimento de mecanismos que facilitem o reparo das coroas metalo-cerâmicas.The current features of ceramic fused to metal crowns were evaluated by means of a questionnaire composed by 20 questions concerning the use of this type of restoration in the daily dental practice of professionals from Aracaju, Bauru and post-graduation students in the area of dental prosthesis. The conclusions were as follows: 1. Ceramic fused to metal crowns are

  9. Pericoronal radiolucency associated with incomplete crown

    Energy Technology Data Exchange (ETDEWEB)

    Nah, Kyung Soo [Dept. of Oral and Maxillofacial Radiology, School of Dentistry, Pusan National University, Yangsan (Korea, Republic of)

    2013-12-15

    The author experienced 8 cases of pericoronal radiolucency involving an incomplete tooth crown that had not developed to form the cemento-enamel junction, and the underdeveloped crown sometimes appeared to be floating within the radiolucency radiographically. The first impression was that these cystic lesions had odontogenic keratocysts, but half of them turned out to be dentigerous cysts histopathologically. There has been no report concerning odontogenic cysts involving an incompletely developed crown. The purpose of this paper is to report that dentigerous cysts may develop before the completion of the cemento-enamel junction of a developing crown.

  10. Preliminary evaluation of clinical effect of computer aided design and computer aided manufacture zirconia crown%计算机辅助设计与辅助制作氧化锆全瓷冠的临床效果初探

    Institute of Scientific and Technical Information of China (English)

    王宇光; 邢燕西; 孙玉春; 赵一姣; 吕培军; 王勇

    2013-01-01

    Objective To evaluate clinical effects of computer aided design and computer aided manufacturing (CAD/CAM) milled zirconia crown in three aspects:aesthetic,contact wear and fracture.Methods Sixty patients were devided into two groups.In one group,35 full contour CAD/CAM zirconia crown were made on molars of 30 patients.The manufacturing process of zirconia crown was as follow.First,the three dimensional(3-D) data of working models,antagonist impression and check records were acquired by 3-D laser scanning Dentalwings S50.Then full contour zirconia crowns,which had functional occlusal contacts with antagonistic teeth,and appropriate contact with adjacent teeth were designed with Zeno-CAD (V4.2.5.5.12919) software.ZENOSTAR Zr pure zirconia material was milled in digital controlled machine WIELAND 4030 M1.In the end,the zirconia crown were completed with the method of second sintering and polishing.After clinical try-in,the crown was cemented.In the control group,thirty gold alloy full crown were made and cemented on molars of 30 patients.According to the modified U S Public Health Service Criteria(USPHS) evaluation standard,all crowns were evaluated on the same day,at three months,half a year,one year and two years following delivery.There were three aspects we were focusing on in the evaluation:aesthetic,contact wear (restoration and antagonist),and fracture.Results In all the prosthesis we evaluated during the 24 months,no fracture was found.Contact wear of crowns varies according to different antagonist teeth.Conclusions The zirconia crowns show privilege in aesthesis,toughness and anti-wearing.However,there is contact wear on antagonistic natural teeth.Thus it is a good choice when full zirconia crowns are indicated on two antagonistic teeth in both jaws.%目的 评价计算机辅助设计与辅助制作氧化锆全瓷冠的临床修复效果,为其临床应用提供参考.方法 选择于北京大学口腔医学院·口腔医院修复科就

  11. Clinical analysis of the influence of temporary crowns on abutment and implant after tooth preparation%牙体制备后临时冠桥修复对基牙及修复体影响的临床分析

    Institute of Scientific and Technical Information of China (English)

    吴启建; 徐敏; 李桂苓

    2015-01-01

    Objective Analysis the effect of temporary crown and bridge repair on the abutment and dental restoration. Methods Randomly selected 80 patients between 2013-2014 a clinical investigation, using retrospective analysis method, the application of direct or indirect method, improve the function, cosmetic repair effect.Results All patients were back on time,within the given time line PFM, casting crown and bridge repair, clinical observation, try effect is good,smooth in place restoration,restoration margin closed closed, try occlusal height is normal, no displacement of abutment teeth, no missing area, elongation polices jaw teeth.Temporary crown bridge can protect the abutment teeth, protect fix clearance and occlusal relationship, avoid teeth mobile embedded plug caused by food, maintain a healthy oral and periodontal tissue. Play a good role.Conclusion The temporary crown and bridge of protect teeth, worth clinical promotion.%目的:分析牙体制备后临时冠桥修复对基牙及修复体的影响。方法选取2013~2014年我院收治的患者80例,采用回顾分析法,应用直接或间接制作方法,提高功能,美观的修复效果。结果本组患者均在规定时间内按时复诊,行烤瓷、铸造冠桥的修复,临床观察,试戴效果良好,顺利就位修复体,修复体边缘封闭密合,试戴咬合高度正常,无基牙移位,无缺失区,対颌牙伸长。临时冠桥的制作能保护基牙,保护修复间隙和咬合关系,避免牙齿移动引起食物嵌塞,维护口腔牙周组织健康。结论临时冠桥所起到的保护牙齿作用,值得临床推广使用。

  12. Clinical research of long-term aesthetic results of the anterior region of zirconia all-ceramic crown%氧化锆全瓷冠在前牙美学修复中的临床应用研究

    Institute of Scientific and Technical Information of China (English)

    王红梅; 杨永进; 蔡兴伟; 郭军; 吕晓宁

    2012-01-01

    目的:探讨氧化锆全瓷冠在前牙美学修复中的应用效果和美学效果的稳定性及其相关影响因素.方法:应用CAD/CAM技术,对20例前牙要求美学修复的患者,共44颗前牙进行氧化锆全瓷冠修复,修复后定期随访2年,通过观察患者对全瓷冠颜色的满意程度,全瓷冠颜色的口内适应情况,颜色的改变情况及牙龈组织的健康状况等,来综合评价氧化锆全瓷冠在前牙美学修复中的应用效果.结果:氧化锆的比色效果在口内的适应性较好,自然美观;两年内患者对其美学效果的评价一致,满意程度高;两年随访观察中只有2例吸烟的男性患者发生颜色改变,其余患者颜色均未发生明显改变,牙龈健康状况良好.结论:氧化锆全瓷冠的前牙美学修复效果良好且稳定,患者满意,具有广阔的应用前景.%Objective To study the repair effect, stability of aesthetic effect and its related factors of zirconia all-ceramic crowns in the anterior dental esthetics restoration. Methods 20 patients who with requirements of anterior teeth aesthetics restoration, a total of 44 anterior teeth of zirconia all-ceramic crown restoration using the CAD/CAM tecnolory, and regular follow-up of 2 years after repair. Then compare the patients' satisfactions on all-ceramic crown color, all-ceramic crown color intraoral adaptation, color changes and the gum tissue health to evaluate the application effect of zirconia all-ceramic crowns in the anterior dental esthetics repair comprehensively. Results The colorimetric effect of zirconia is natural appearance in the mouth; all the patients show high levels of satisfaction during two years follow-up observation on the aesthetic evaluation of the effect of consistent.Only two smoking male patients with color change and the remaining patients had no obvious color change.and the gingival health is good. Conclusion The repair effect of zirconia all-ceramic crown of anterior dental esthetics is

  13. Clinical study of telescopic crown retained denture on the restoration of dentition defect in patients with light, modertate periodontal disease%筒冠义齿修复轻中度牙周炎伴多数牙缺失的疗效观察

    Institute of Scientific and Technical Information of China (English)

    王红梅; 杨永进; 蔡兴伟; 吕晓宁; 李雅彬; 李晖

    2012-01-01

    目的:探讨多数牙缺失伴牙周病的牙列缺损患者应用套筒冠修复的临床效果.方法:选择多数牙缺失并有可摘局部义齿修复史的轻中度牙周炎患者36例,行牙周基础治疗和根管治疗后设计、制作套筒冠义齿,比较分析修复前和修复后6、12、24个月菌斑指数(PLI)、牙龈指数(GI)、探诊深度(PD)、龈沟出血指数(SBI)、牙齿松动度,并进行问卷调查.结果:36例患者在修复后3次复查时牙齿松动度和牙周袋深度(PD)逐渐变小(P0.05);随访问卷调查结果显示,患者对套筒冠义齿满意度明显高于活动义齿.结论:套筒冠义齿修复轻中度牙周炎伴多数牙缺失的牙列缺损具有较好的临床效果.%Objective: To explore the clinical result of using telescopic crown retained denture to restore dentition defect in patients with most teeth missing and periodontal disease. Methods: Thirty-six cases with dentition defect and periodontal disease were recruited. After the comprehensive periodontal therapy and root canal treatment, telescopic crown retained partial dentures were made and tried in. Plaque index (PLI), gingival index (GI), probing index(PD), sulcus bleeding index (SBI) and mobility of teeth were checked and recorded before and 6, 12, 24 months after restoration. The patients were investigated with questionnaires concerning the results. Results: Teeth mobility and PD were significantly improved (P0.05). The results of questionnaires indicated that the patients were much more satisfied with telescopic crown dentures than their original removable partial dentures. Conclusion: Using telescopic crown retained dentures to repair dentition defect in patients with periodontal disease could ensure good clinical results.

  14. Seal capability of interim post and core crown with temporary cements

    Directory of Open Access Journals (Sweden)

    Guilherme Bönecker-Valverde

    2010-06-01

    Full Text Available The purpose of the present study was to evaluate the in vitro seal capability of interim post and core crown restorations. Eighty teeth were selected and divided into 8 groups. Four experimental groups received interim posts and core crowns. Half of each group was decoronated at the cementum-enamel junction, groups PCCH and PCZO. The other half was sectioned 2 mm coronal to the cementum-enamel junction, groups PCrZO and PCrCH. The interim post and core crowns were luted with Rely X Temp NE, groups PCrZO and PCZO; Hydro C was used for Groups PCrCH and PCCH. The control groups, PC and PCr, received uncoated post and core crowns; groups OTg and OT were left without interim post and core crowns and were totally open. Infiltration was accessed by dye exposure followed by demineralization of the teeth. The length of the infiltration was measured using digital images taken from the specimens. The images were inserted into the Image Tool 3.0 software. Kruskal-Wallis analysis of variance and Dunn's multiple comparison method were used to test for significant differences among test groups (P < .05. Groups PCrZO and PCrCH showed the least dye penetration, followed by groups PCZO and PCCH. Teeth restored with interim post and core crowns will be subject to leakage. Ethics Committee: 095/2008.

  15. The use of tree crown variables in over-bark diameter and volume prediction models

    Directory of Open Access Journals (Sweden)

    Özçelik R

    2014-06-01

    Full Text Available Linear and nonlinear crown variable functions for 173 Brutian pine (Pinus brutia Ten. trees were incorporated into a well-known compatible volume and taper equation to evaluate their effect in model prediction accuracy. In addition, the same crown variables were also incorporated into three neural network (NN types (Back-Propagation, Levenberg-Marquardt and Generalized Regression Neural Networks to investigate their applicability in over-bark diameter and stem volume predictions. The inclusion of crown ratio and crown ratio with crown length variables resulted in a significant reduction of model sum of squared error, for all models. The incorporation of the crown variables to these models significantly improved model performance. According to results, non-linear regression models were less accurate than the three types of neural network models tested for both over-bark diameter and stem volume predictions in terms of standard error of the estimate and fit index. Specifically, the generated Levenberg-Marquardt Neural Network models outperformed the other models in terms of prediction accuracy. Therefore, this type of neural network model is worth consideration in over-bark diameter and volume prediction modeling, which are some of the most challenging tasks in forest resources management.

  16. Wear of double crown systems: electroplated vs. casted female part

    Directory of Open Access Journals (Sweden)

    Stefan Bayer

    2012-06-01

    Full Text Available OBJECTIVES: The wear of telescopic crowns is a common problem often reducing the patient's satisfaction with the denture and resulting in a renewal of the denture. The study aims to compare the wear behavior of conical crowns using electroplated copings (group E with standard telescopic crowns with cast female parts (group C. MATERIAL AND METHODS: 10 conical crowns were milled for each group of a cast gold alloy. The specimen of group E had a conicity of 2º. The cast secondary crowns of group C had a 0º design. The electroplated coping was established by direct electroforming. An apparatus accomplishing 10,000 wear cycles performed the wear test. The retentive forces and the correlating distance during insertion and separation were measured. The wear test was separated in a start phase, an initial wear phase and the long term wear period. The retention force value and the force-distance integral of the first 0.33 mm of each cycle were calculated. RESULTS: The retentive forces were significantly higher for group E and the integrals were significantly lower for this group except the integral at cycle 10,000. The changes of retention force and integral did not differ significantly between both groups in all phases. The change of the integrals as well as the integral at the particular cycles showed higher interquartile distances for group C. CONCLUSIONS: Within the limitations of this study the tested conical crowns showed clinically acceptable retentive properties. The values reached a range comparable to retentive elements tested in recent literature. The values of group C showed higher ranges. The force measured for group E was significantly higher than for group C but the integrals showed an opposite tendency. The results indicate that an exclusive analysis of the force is not sufficient as the integral is not equivalent to the force although it describes the retentive property of the system in a better way than the force over a distance is

  17. Esthetic crown lengthening for maxillary anterior teeth.

    Science.gov (United States)

    Sonick, M

    1997-08-01

    In the maxillary anterior region, the gingival labial margin position is an important parameter in the achievement of an ideal smile. The relationship between the periodontium and the restoration is critical if gingival health and esthetics are to be achieved. Periodontal therapy is a necessary and useful adjunct when any anterior restoration is undertaken. Anterior surgical crown lengthening may be undertaken to avoid restorative margin impingement on the biologic width. Crown lengthening is also used to alter the gingival labial profiles. This article discusses the esthetic parameters of ideal gingival labial positions and presents a classification of crown-lengthening procedures and the procedure for a two-stage crown-lengthening technique. The two-stage crown-lengthening technique is surgically precise because healing is predictable.

  18. The clinical study on abutment dentin hypersensitivity after preparation for crown and bridge%冠桥基牙制备后牙本质敏感的临床治疗研究

    Institute of Scientific and Technical Information of China (English)

    邓文正; 郭庆; 陆辉; 邱伟芳

    2013-01-01

    Objective To evaluate the effects of professional oral allergy desensitization paste for treating abutment dentin hypersensitivity after preparation for Crown and bridge.Methods 226 patients,repaired by porcelain Crown and bridge,were randomly divided into test group and control group,n =113.Test group:Professional oral allergy desensitization paste was used after tooth preparation and before bonding the ceramic Crown and bridge,for 113 cases.Control group:Gluma desensitizer was used after tooth preparation and before bonding the ceramic Crown and bridge,for 113 cases.Adopted cold air blowing,dentin sensitivity was evaluated by recording the value of visual analogue pain scores (VAS).Results The abutment sensitivity of the test group,by using desensitizing paste therapy after tooth preparation,significantly reduced.The abutment sensitivity after desensitizing paste therapy was statistically significant compared with that of before using desensitization paste and control group (P<0.001).The abutment sensitivity of test group was statistically significant compared with that of control group after the ceramic Crown and bridge was bonded (P<O.O01).Conclusion Professional oral allergy desensitization paste has good effect on treating abutment dentin hypersensitivity after preparation for Crown and bridge.%目的:评价抗敏口腔专业用脱敏膏对于烤瓷冠桥基牙制备后牙本质过敏的治疗疗效.方法:选取做烤瓷冠桥修复的226例患者,随机分为实验组和对照组,各113例.实验组:113例备牙后和烤瓷冠桥粘固前使用抗敏口腔专业用脱敏膏进行脱敏.对照组:113例备牙后、烤瓷冠桥粘固前使用Gluma脱敏剂脱敏.牙本质敏感度的评价采用冷空气喷吹法,记录视觉模拟疼痛评分(visual analogue scale,VAS)值.结果:实验组于备牙后使用脱敏膏治疗基牙敏感显著降低,与使用前对照组比较差异有统计学意义(P<0.001);与对照组相比,实验组粘固后基牙敏

  19. A new flapless technique for crown lengthening after orthodontic extrusion.

    Science.gov (United States)

    Braga, Giovanni; Bocchieri, Anna

    2012-02-01

    Orthodontic extrusion (OE), which is performed in many different clinical situations to move a tooth or its periodontal tissues coronally, is often associated with supracrestal fiberotomy and root planing (OEFRP) or followed by surgical crown lengthening. The OEFRP procedure must be carried out every 2 weeks during the entire extrusive orthodontic phase, and precise control of the technique itself can be quite difficult, especially when this approach is to be performed on a limited portion of the root perimeter in teeth affected by angular defects. The aim of this study was to show a new nonsurgical crown-lengthening technique, performed shortly after the completion of OE, to simultaneously achieve proper hard and soft tissue architecture. Three different illustrative situations (periodontal pocket, root fracture, and root perforation) are described.

  20. Fabrication of all-ceramic crowns by a new method.

    Science.gov (United States)

    Masuda, Takayuki; Kakimoto, Kazutoshi; Takahashi, Kazuya; Komasa, Yutaka

    2016-01-01

    A new method of all-ceramic production using alumina coping has been developed. The present study investigates the influence of secondary firing (glass infiltration firing) conditions. Samples of porcelain build-up without secondary firing were also assessed. The suitability of coping that included secondary firing was found to be affected by the rate of temperature increase during the secondary firing. However, cracking developed in the fired porcelain if porcelain was built up onto secondarily-fired coping. In contrast, cracking did not occur with coping that was not secondarily fired. The bending strength after porcelain build-up was 70 MPa or higher, suggesting the possibility of clinical applications as an anterior crown. These findings establish that this is method of producing all-ceramic crowns that allows for low-cost manufacture in a short period of about 1 h. PMID:27041020

  1. 不同高度全口覆盖义齿短冠基牙根面临床观察%Clinical observation of different short crown root surface height complete overlay denture base

    Institute of Scientific and Technical Information of China (English)

    田丽; 杨军成

    2012-01-01

    目的探讨全口覆盖义齿基牙根面不同高度牙龈病的发病率.方法随机选择30例口内有多个残根残冠的中老年患者,选择符合条件的残根或残冠共126个基牙经治疗后.将残根残冠根面预备平整,上颌残根根面平齐龈缘,下颌残根根面高出龈缘1-2mm.根管口及根面均采用光固化树脂充填,然后进行常规全口义齿修复.观察两种不同方法牙龈炎的发病率.结果30例全口覆盖义齿患者中平齐龈缘的残根龈炎发病率较高.结论选择全口覆盖义齿修复方式时,短冠基牙残根根面高度预备最好高出龈缘1-2mm,可以预防牙周炎的发生.%Objective : Study of complete overdenture based on root surface in different height of gingival disease incidence rate Methods: In 30 randomly selected patients with a number of residual root and crown in the elderly patients, Selection of eligible residual roots or crowns in a total of 126 abutment teeth after the treatment, The residual crown and root to root surface preparation leveling, maxillary residual root surface flush gingival margin, Mandibular residual root surface above the gingival margin 1-2mm, Root canal orifice and root surface using light curing resin filling, then the conventional complete denture restoration. Observe the effect of two different methods the incidence of gingivitis. Results:In 30 patients with complete overlay denture patients with gingival margin in a higher incidence of residual root gingivitis. Conclusion: Selection of overlay denture repairing mode, Short crown abutment teeth residual root surface height above the gingival margin 1-2mm is the better mode, it can prevent the onset of periodontitis.

  2. Evaluation of the marginal and internal gap of metal-ceramic crown fabricated with a selective laser sintering technology: two- and three-dimensional replica techniques

    OpenAIRE

    Kim, Ki-Baek; Kim, Jae-Hong; Kim, Woong-Chul; Kim, Hae-Young; Kim, Ji-Hwan

    2013-01-01

    PURPOSE One of the most important factors in evaluating the quality of fixed dental prostheses (FDPs) is their gap. The purpose of this study was to compare the marginal and internal gap of two different metal-ceramic crowns, casting and selective laser sintering (SLS), before and after porcelain firing. Furthermore, this study evaluated whether metal-ceramic crowns made using the SLS have the same clinical acceptability as crowns made by the traditional casting. MATERIALS AND METHODS The 10 ...

  3. Influence of different post core materials on the color of Empress 2 full ceramic crowns

    Institute of Scientific and Technical Information of China (English)

    GE Jing; WANG Xin-zhi; FENG Hai-lan

    2006-01-01

    Background For esthetic consideration, dentin color post core materials were normally used for all-ceramic crown restorations. However, in some cases, clinicians have to consider combining a full ceramic crown with a metal post core. Therefore, this experiment was conducted to test the esthetical possibility of applying cast metal post core in a full ceramic crown restoration.Methods The color of full ceramic crowns on gold and Nickel-Chrome post cores was compared with the color of the same crowns on tooth colored post cores. Different try-in pastes were used to imitate the influence of a composite cementation on the color of different restorative combinations. The majority of patients could not detect any color difference less than △E 1.8 between the two ceramic samples. So, △E 1.8 was taken as the objective evaluative criterion for the evaluation of color matching and patients' satisfaction.Results When the Empress 2 crown was combined with the gold alloy post core, the color of the resulting material was similar to that of a glass fiber reinforced resin post core (△E = 0.3). The gold alloy post core and the try-in paste did not show a perceptible color change in the full ceramic crowns, which indicated that the color of the crowns might not be susceptible to change between lab and clinic as well as during the process of composite cementation. Without an opaque covering the Ni-Cr post core would cause an unacceptable color effect on the crown (△E = 2.0), but with opaque covering, the color effect became more clinically satisfactory (△E=1.8).Conclusions It may be possible to apply a gold alloy post core in the Empress 2 full ceramic crown restoration when necessary. If a non-extractible Ni-Cr post core exists in the root canal, it might be possible to restore the tooth with an Empress 2 crown after coveting the labial surface of the core with one layer of opaque resin cement.

  4. RTD MACRO-LOCK POST固位增强型石英纤维桩与金属桩修复上颌前牙残冠的临床疗效比较%Clinical Effect Contrast Between RTD MACRO-LOCK POST Retentive Enhanced Quartz Fiber Post and Metal Post In Restoration Of Residual Crown Of Maxillary Anterior Teeth

    Institute of Scientific and Technical Information of China (English)

    韩凉; 袁方; 应王贵

    2012-01-01

    Objective Clinical effect contrast between RTD MACRO-LOCK POST retentive enhanced quartz fiber post and metal post in restoration of residual crown of maxillary anterior teeth. Methods Select 200 cases with maxillary anterior teeth defect, randomly divide into 2 groups. Use RTD MACRO-LOCK POST retentive enhanced quartz fiber post and metal post for post core crown, observe and compare the clinical effects after 3 years. Results There is no significant difference between 2 groups after 6 months (P>0.05). The clinical success rate of fiber post group is higher than that of the metal post group after 3 years (P<0.05 ). Conclusion With correct choice of indications, the clinical effect of RTD MACRO-LOCK POST retentive enhanced quartz fiber post is better than that of the metal post.%目的 观察RTD MACRO-LOCK POST固位增强型石英纤维桩与金属桩修复上颌前牙残冠的临床疗效.方法 选取上颌前牙牙体缺损患者200例,随机分为两组,分别采用RTD MACRO-LOCK POST固位增强型石英纤维桩与金属桩进行桩核冠修复,随访观察3年.结果 纤维桩组患者修复后6个月临床成功率与金属桩组无明显区别(P>0.05),修复后3年临床成功率高于金属桩组(P<0.05).结论 在正确选择适应证前提下,RTD MACRO-LOCK POST固位增强型石英纤维桩修复效果优于金属桩.

  5. 分根术加全冠修复大面积髓室底穿孔磨牙的临床疗效观察%Clinical effectiveness of root separation and full crown rapair on treatment of large areas perforation of dental pulp floor of molars

    Institute of Scientific and Technical Information of China (English)

    汪文银; 朱友家

    2013-01-01

    Objective:To investigate the clinical effectiveness of root separation and full crown rapair on treatment of large areas perforation of dental pulp floor of molars. Method: 120 out patients that had large areas perforation of dental pulp floor of molars were randomly dived into the experimental group and control group 60 cases. Experimental group use the treatment of root separation and full crown rapair,control group use the treatment of light-cured calcium hydratide and zinic phosphate cement basing with amalgam restoration and full crown repair. Result:Successful rate of experimental group was 83.33 %,response rate was 96.67 %. Successful rate of control group was 43.33 %,response rate was 83.33 %,there was a significant difference between two groups(P <0.01). Conclusion:The use of root separation and full crown rapair can obtain a better effect for treatment of large areas perforation of dental pulp floor of molars.%目的:观察分根术加全冠修复大面积髓室底穿孔磨牙的临床疗效.方法:门诊收治陈旧性大面积髓室底穿孔(直径>3 mm)的磨牙病例120例.随机分成实验组60例,对照组60例.实验组采用分根术加全冠修复治疗,对照组采用光固化型氢氧化钙,磷酸锌粘固粉垫底,银汞充填.全冠修复治疗.结果:随访3~5年,实验组成功率83.33%,有效率96.67%,对照组成功率43.33%,有效率83.33%.实验组临床疗效明显优于对照组(P<0.01).结论:分根术加全冠修复大面积髓室底穿孔磨牙具有较好的临床疗效.

  6. Flame Length

    Data.gov (United States)

    Earth Data Analysis Center, University of New Mexico — Flame length was modeled using FlamMap, an interagency fire behavior mapping and analysis program that computes potential fire behavior characteristics. The tool...

  7. Effect of Luting Cement Space on the Strain Response of Gold Crowns Under Static Compressive Loading.

    Science.gov (United States)

    Asbia, S; Ibbetson, R; Reuben, B

    2015-03-01

    The aim the work was to investigate the effect of varying degrees of luting cement thickness on the strain of the cemented gold alloy crowns under compression. Five dies with their corresponding crowns were fabricated using a lost wax technique. Three gold crowns for each die were fabricated under the control of specific die spacer layers to provide a space of 40 µm (10 layers of die-spacer thickness) and 80 µm (20 layers of die-spacer thickness). The crowns were subsequently cemented using zinc phosphate cement. The crowns were subjected to gradual static compressive loading between 10N to 250N (Newton) and the strain measured simultaneously. The results were statistically analysed using Independent t-test for the different die-spacer thickness at the 95% confidence interval (p = 0.05). It was found that a significant relationship in the three thicknesses. It was concluded that the absence of die-spacer significantly reduced strain response, whereas a very little change in the strain recorded as the die spacer layers has increased. Clinically, decreasing the number of die-spacer layers is advantageous as it provides a lower strain response under static compressive loading that would improve the longevity of the cemented full crowns inside the patient's mouth. PMID:26415332

  8. The aesthetic treatment for anterior teeth with lost crown by endorestoration

    Directory of Open Access Journals (Sweden)

    Nanik Zubaidah

    2009-06-01

    Full Text Available Background: The aesthetic has an important role in social life, especially the anterior teeth. The aesthetic abnormality of anterior teeth i.e. discoloration, malpotition or the anterior teeth with crown damage for more than one third or all part of crown is lost due to caries or other causes, will influence its appearance especially during smile. Purpose: The aim of this case report, therefore, is to show how teeth with clinical crown lost or only the root left still can be treated by endorestoration treatment in order to reconstruct the shape and function of the teeth similar to the original ones. Case: Female 52 years old with the lost crown of anterior teeth. The patient did not want her teeth to be extracted. Case Management: The abnormality of these teeth are still able to be reconstructed by endorestoration i.e. endodontic treatment with post and core insertion in the root canal will increase its retention and recovery by the porcelain crown fused to metal to recover the original formation and aesthetic and thus has the normal refunction. The treatment, it improve the confidence of the patient, and also can function normally. The patient did not feel pain. Ronsenography showed the periapical lesion diminished, the neighbor gingival was going better in both function and color. Conclusion: Endorestoration treatment on the anterior teeth with lost crown could recover the normal function, dental aesthetic and self confidence.

  9. Calix[4] crowns with Methoxynaphthoylmethyl Pendant Groups

    Institute of Scientific and Technical Information of China (English)

    金传明; 陆国元; 张超智; 施证伟; 游效曾

    2003-01-01

    The novel calix [4] crowns with two pendant groups were prepared by the alkylation of calix 141 crowns with 6-methoxy-2-bromoacetylnaphthalene. 1H NMR titration and picrate extraction experiments indicated that they exhibit higher complexing efficiency than their parent compounds and possess obvious selectivity for Na+ or K+ , respetively, and that the cation is encapsulated inside the preorganized ionophoric cavity defined by carbonyl oxygens, the crown ether and the phenoxy oxygens.From UV and fluorescent spectra it is revealed that calix [4]crown-4 3a with 6-methoxy-2-naphthoylmethyl pedant groups exhibits remarkable cation-induced photophysical effects and it could be utilized as a selective fluorescent sensor for Ca2+.

  10. Activity relationships for aromatic crown ethers

    CERN Document Server

    Wilson, M J

    1998-01-01

    This thesis involves an investigation of aromatic crown ethers and a study of their binding constants for alkali metals. The study was motivated by the current needs of the semiconductor industry to improve the scavenging of mobile ions from fabricated circuits. A number of aromatic crown ethers have been sulphonated in an attempt to improve their water solubility and cation binding activity. These materials have been extensively studied and their binding activity determined. In collaboration with a molecular modelling study, the effect of ionisable sulphonate groups on the macrocycles' behaviour has been investigated. The broader issue of the effect of substituents in aromatic crown ethers has also been studied with the preparation of a wide range of substituted crown ethers. The cation binding activity of these materials has been found to bear a simple relationship to the electron withdrawing nature of the aromatic substituents. This relationship can be accurately monitored using electronic charge densities...

  11. Treatment of crown dilaceration: an interdisciplinary approach.

    Science.gov (United States)

    Subramaniam, P; Naidu, P

    2010-01-01

    Trauma to primary teeth can result in a wide range of disturbances to the underlying permanent teeth, such as dilaceration. Root dilacerations occur more commonly than crown dilacerations. This paper is a report of an 11-year-old girl with a missing maxillary left anterior tooth. Past history revealed premature loss of primary maxillary anterior teeth due to trauma. Radiographic examination revealed crown dilaceration of permanent maxillary left central incisor. An interdisciplinary approach in the management of this child is presented herewith.

  12. In vitro morphogenetic competence of basal sprouts and crown branches of mature chestnut.

    Science.gov (United States)

    Sánchez, M C; Vieitez, A M

    1991-01-01

    Basal shoots of five clones of mature chestnut tree (Castanea sativa Mill. and C. sativa x C. crenata Siebold & Zucc.) had a greater capacity for in vitro establishment, multiplication and rooting than crown branches of the same trees. Cultures from basal shoots were more responsive than crown-derived cultures in terms of in vitro reactivity (proportion of the explants with shoot development), the mean number of shoots formed per explant, the length of the tallest shoot in each culture, and the multiplication coefficient (defined as the product of the reactivity and the mean number of shoots per explant). Multiplication coefficients were greatest between subcultures 6 and 12, but subculturing failed to increase the rooting potential of shoots of crown origin. Multiplication and rooting rates were also determined for clones derived from seeds of mature trees. Genotype influenced the in vitro performance of clones of both adult and seedling origins.

  13. 超声骨刀行冠延长术后纤维桩修复上颌前牙的临床应用%Clinical application of fiber posts in restoring maxillary anterior teeth after surgical crown lengthening by piezosurgery

    Institute of Scientific and Technical Information of China (English)

    李张维; 康成容; 吴妹娟; 王玉栋; 潘宣

    2015-01-01

    目的 观察保留冠折位于龈下的上颌前牙残根残冠,使用超声骨刀行冠延长术后纤维桩修复的临床疗效.方法 27例患者共32颗患牙,经完善的根管治疗后使用超声骨刀行冠延长术,术后6周复诊,采用纤维桩、双固化树脂水门汀及复合树脂材料恢复桩核,二氧化锆烤瓷冠修复.术后通过临床和X线片检查评估修复体的临床疗效.结果 27例患者的32颗患牙经过1~3年期间的随访检查,成功29颗(90.6%),失败3颗(9.4%).结论 超声骨刀应用于上颌前牙冠延长术,并联合纤维桩修复,可取得良好的治疗效果.%Objective To observe the clinical effects of fiber posts in restoring maxillary anterior teeth after surgical crown lengthening by piezosurgery. Methods After root canal therapy, 32 teeth from 27 patients were lengthened with piezosurgery. After 6 weeks, they were restored by fiber posts, dual cure resin cement, composite res-in material. And then, zirconia crowns were applied to restore them. The patients were observed the restoration effects by clinical results and X-ray. Results The 32 teeth from 27 patients were followed up for 1~3 years, with 29 teeth successfully restored (90.6%) and 3 teeth unsuccessfully restored (9.4%). Conclusion A satisfactory treatment ef-fects could be achieved by surgical crown lengthening with piezosurgery and fiber posts in restoring maxillary ante-rior teeth.

  14. The clinical effect of direct pulp capping with multi-cal in crown fracture with pulp exposure in incisors%氢氧化钙糊剂治疗前牙冠折露髓的短期疗效观察

    Institute of Scientific and Technical Information of China (English)

    张文奎; 刘勇

    2011-01-01

    目的 观察氢氧化钙糊剂治疗前牙冠折露髓的短期治疗效果.方法 回顾性分析14例使用氢氧化钙糊剂+爱诺赛光固化复合体+可乐丽菲露树脂修补前牙冠折露髓(≤2 mm)患者的临床资料,评价此方法的短期治疗效果.结果 14例患者共16颗患牙1例患者的1颗患牙因冠髓部分切除行直接盖髓术后第2天出现自发痛及夜间痛复诊,诊断为急性牙髓炎,局部麻醉下行一次性根管治疗;其余13例患者的15颗患牙3个月内均无自发疼痛,临床及X线检查无异常.短期观察治疗成功率为93.8%.结论 氢氧化钙糊剂在前牙冠折露髓中有较好的治疗效果.%Objective To evaluate the method in treatment pulp exposure caused by crown fracture with Multi-cal and the its clinical effect. Methods In the retrospective study, 14 cases ( 16 teeth)were treated to repair pulp exposure with Multi-cal, Ionosit-Baseliner, SE-BOUND and AP-X after debridement. To evaluate the result in short-term with pulp vitality detection and X-ray after three months. Results One tooth treated with direct pulp capping after partial crown-pulptomy appeared spontaneous pain and night pain. The tooth was diagnosed with acute pulpitis and treated with one-step root canal therap under local anesthesia. Other 15 teeth were successfully treated.in 3 months with no spontaneous pain. Clinical and X-ray examination were normal. The success rate was 93.8% in short-term. Conclusion Multi-cal is an effective material in treatment of crown fracture with pulp exposure.

  15. Genetic diversity of Trichomonas vaginalis clinical isolates determined by EcoRI restriction fragment length polymorphism of heat-shock protein 70 genes.

    Science.gov (United States)

    Meade, John C; de Mestral, Jacqueline; Stiles, Jonathan K; Secor, W Evan; Finley, Richard W; Cleary, John D; Lushbaugh, William B

    2009-02-01

    Restriction fragment length polymorphism (RFLP) analysis using a multilocus heat-inducible cytoplasmic heat-shock protein 70 (Hsp70) hybridization probe with EcoRI-digested genomic DNA was used in molecular typing of 129 Trichomonas vaginalis isolates. Results indicate that Trichomonas organisms exhibit considerable polymorphism in their Hsp70 RFLP patterns. Analysis of seven American Type Culture Collection reference strains and 122 clinical isolates, including 84 isolates from Jackson, Mississippi, 18 isolates from Atlanta, Georgia, and 20 isolates from throughout the United States, showed 105 distinct Hsp70 RFLP pattern subtypes for Trichomonas. Phylogenetic analysis of the Hsp70 RFLP data showed that the T. vaginalis isolates were organized into two clonal lineages. These results illustrate the substantial genomic diversity present in T. vaginalis and indicate that a large number of genetically distinct Trichomonas isolates may be responsible for human trichomoniasis in the United States. PMID:19190222

  16. Clinical Evaluation on Crown Lengthening Surgery Adapted in Aesthetic Restoration for Individual Upper Anterior Tooth with Palatal Incline%牙冠延长术应用于个别腭侧倾斜上前牙美容修复的临床效果评价

    Institute of Scientific and Technical Information of China (English)

    符镇南; 陈儒娜; 邹康元

    2011-01-01

    Objective To evaluate the clinical effect of crown lengthening surgery adapted in aesthetic restoration for individual upper anterior tooth with palatal incline. Methods Thirty-six upper anterior teeth were treated by crown lengthening surgery and restored with metal porcelain crown. After 2 years follow-up,the esthetics and gingival health were by examining oral adaptability of crown margin,cervical margin,GI,PD and TM. Results During the 2 years,all of the cervical margins were good,and all of the teeth did not have peridentioelasia. The aesthetic effects of the restorations were all satisfactory. Conclusion Crown lengthening surgery adapted in aesthetic restoration for individual upper anterior tooth with palatal incline can achieve a good cosmetic restoration purpose.%目的 评价牙冠延长术应用于个别腭侧倾斜上前牙美容修复的临床疗效.方法 36例36颗腭侧倾斜的上颌前牙,21颗采用单纯切龈后冠修复,15颗采用切龈翻瓣去骨后冠修复.修复后6个月、2年随访,检查冠颈缘适合性、龈缘协调性,回访患者对咀嚼功能的主观评价,评价患牙牙周健康状况,包括牙龈指数、牙周探诊深度和牙齿松动度.结果 36例患者于术后6个月及2年复诊检查,患者对术牙功能的主观评价均满意,临床检查36个烤瓷冠的颈缘适合性好,龈缘协调性均满意,术牙均无松动.21颗单纯切龈后冠修复的患牙(x2=0.43,P>0.05)和15颗切龈翻瓣去骨后冠修复的患牙(x2=1.45,P>0.05)牙龈指数与术前比较差异均无统计学意义.单纯切龈后冠修复的患牙(F=2.98,P>0.05)和切龈翻瓣去骨后冠修复的患牙(F= 1.52,P>0.05)牙周探诊深度与术前比较差异均无统计学意义.结论 牙冠延长术应用于个别腭侧倾斜上前牙美容修复可以达到良好的临床疗效.

  17. Clinical study of crown shape control effect of horizontal food impaction in implant supported fixed denture in elderly patients%牙冠形态对老年种植修复患者水平型食物嵌塞防治效果的临床研究

    Institute of Scientific and Technical Information of China (English)

    崔广; 刘宇; 郑洁; 宫琳

    2014-01-01

    目的:观察不同邻面形态的种植单冠修复后对老年种植患者后牙水平型食物嵌塞的防治效果。方法:将80例老年患者第一磨牙种植冠按修复间隙的大小分成两组(A组距离<10.0mm, B组≥10.0mm),组内再随机分为对照组和试验组各20例,分别按照不同邻面形态制作硬质树脂临时冠并戴入,两两对比并进行随访观察。所有病例在观察6个月后拆除硬质树脂临时冠,使用全解剖形态氧化锆种植冠完成最终修复。结果:不同大小的修复间隙,对照组食物嵌塞情况均严重于试验组,两者存在显著性差异(P<0.05)。结论:针对不同大小的修复间隙,特殊的种植冠邻面形态短期内有利于防治老年患者后牙水平型食物嵌塞,长期的临床效果需进一步研究证实。%Objective:Food impaction is one of the main complications of fixed partial denture restoration, and implant supported fixed partial denture is no exception, especially horizontal food impaction. The current study aim to examine the treatment effects of food impaction by adjusting the interproximal contour of the implant crowns.Method:80 cases of posterior teeth restored with implant crowns were randomly divided into group A(<10.0mm), and group B(≥10.0mm), according to the edentulous space. Each group was then subdivided into two groups, each with 20 cases, that were restored with temporary resin crown of different interproximal contour, replaced by zirconia-ceramic crowns 6 month later. Proximal contact, the occurrence of horizontal food impaction and clinical parameters were recorded at each time point. All results were futher compared and analyzed statistically.Results:In group A, the food impaction rate of the control group and experimental group was 80% and 25%, respectively. In group B, the food impaction rate of the control group and experimental group was 100% and 15%, respectively. The food impaction rates of both experiment

  18. BAY 81-8973, a full-length recombinant factor VIII: Human heat shock protein 70 improves the manufacturing process without affecting clinical safety.

    Science.gov (United States)

    Maas Enriquez, Monika; Thrift, John; Garger, Stephen; Katterle, Yvonne

    2016-11-01

    BAY 81-8973 is a full-length, unmodified recombinant human factor VIII (FVIII) approved for the treatment of hemophilia A. BAY 81-8973 has the same amino acid sequence as the currently marketed sucrose-formulated recombinant FVIII (rFVIII-FS) product and is produced using additional advanced manufacturing technologies. One of the key manufacturing advances for BAY 81-8973 is introduction of the gene for human heat shock protein 70 (HSP70) into the rFVIII-FS cell line. HSP70 facilitates proper folding of proteins, enhances cell survival by inhibiting apoptosis, and potentially impacts rFVIII glycosylation. HSP70 expression in the BAY 81-8973 cell line along with other manufacturing advances resulted in a higher-producing cell line and improvements in the pharmacokinetics of the final product as determined in clinical studies. HSP70 protein is not detected in the harvest or in the final BAY 81-8973 product. However, because this is a new process, clinical trial safety assessments included monitoring for anti-HSP70 antibodies. Most patients, across all age groups, had low levels of anti-HSP70 antibodies before exposure to the investigational product. During BAY 81-8973 treatment, 5% of patients had sporadic increases in anti-HSP70 antibody levels above a predefined threshold (cutoff value, 239 ng/mL). No clinical symptoms related to anti-HSP70 antibody development occurred. In conclusion, addition of HSP70 to the BAY 81-8973 cell line is an innovative technology for manufacturing rFVIII aimed at improving protein folding and expression. Improved pharmacokinetics and no effect on safety of BAY 81-8973 were observed in clinical trials in patients with hemophilia A.

  19. BAY 81-8973, a full-length recombinant factor VIII: Human heat shock protein 70 improves the manufacturing process without affecting clinical safety.

    Science.gov (United States)

    Maas Enriquez, Monika; Thrift, John; Garger, Stephen; Katterle, Yvonne

    2016-11-01

    BAY 81-8973 is a full-length, unmodified recombinant human factor VIII (FVIII) approved for the treatment of hemophilia A. BAY 81-8973 has the same amino acid sequence as the currently marketed sucrose-formulated recombinant FVIII (rFVIII-FS) product and is produced using additional advanced manufacturing technologies. One of the key manufacturing advances for BAY 81-8973 is introduction of the gene for human heat shock protein 70 (HSP70) into the rFVIII-FS cell line. HSP70 facilitates proper folding of proteins, enhances cell survival by inhibiting apoptosis, and potentially impacts rFVIII glycosylation. HSP70 expression in the BAY 81-8973 cell line along with other manufacturing advances resulted in a higher-producing cell line and improvements in the pharmacokinetics of the final product as determined in clinical studies. HSP70 protein is not detected in the harvest or in the final BAY 81-8973 product. However, because this is a new process, clinical trial safety assessments included monitoring for anti-HSP70 antibodies. Most patients, across all age groups, had low levels of anti-HSP70 antibodies before exposure to the investigational product. During BAY 81-8973 treatment, 5% of patients had sporadic increases in anti-HSP70 antibody levels above a predefined threshold (cutoff value, 239 ng/mL). No clinical symptoms related to anti-HSP70 antibody development occurred. In conclusion, addition of HSP70 to the BAY 81-8973 cell line is an innovative technology for manufacturing rFVIII aimed at improving protein folding and expression. Improved pharmacokinetics and no effect on safety of BAY 81-8973 were observed in clinical trials in patients with hemophilia A. PMID:27436242

  20. Tooth wear against ceramic crowns in posterior region:a systematic literature review

    Institute of Scientific and Technical Information of China (English)

    Rim Hmaidouch; Paul Weigl

    2013-01-01

    The objective of this systematic review was to assess tooth wear against ceramic crowns in posterior region in vitro and in vivo. An electronic PubMed search was conducted to identify studies on tooth wear against ceramic crowns in posterior region. The selected studies were analyzed in regard to type of crowns, natural antagonist, measuring protocol and outcome. From a yield of 1 000 titles, 43 articles were selected for full-text analysis;finally, no in vitro and only five in vivo studies met the inclusion criteria. As there is heterogeneity in design, used measuring method, ceramics and analysis-form, a meta-analysis was not possible. Results of these studies are very controversial which makes a scientifically valid comparison impossible. This review indicated that some all-ceramic crowns are as wear friendly as metal-ceramic crowns. Up to now, it has been impossible to associate tooth wear with any specific causal agent. The role of ceramic surface treatment that might be responsible for the changing in rate of tooth wear seems undetermined as yet through clinical trials. The literature reveals that studies on this topic are subject to a substantial amount of bias. Therefore, additional clinical studies, properly designed to diminish bias, are warranted.

  1. Clinical analysis on removable partial denture in Kennedy Ⅰ dentition defect after Loose abutments were fixed by combined crowns%联冠固定松动基牙后可摘义齿修复肯氏I类牙列缺损的临床疗效观察

    Institute of Scientific and Technical Information of China (English)

    顾斌; 李萍; 刘娜; 刘洪臣

    2012-01-01

    Objective: To evaluate clinical therapeutic effect of removable partial denture on Kennedy I dentition defect after loose abutment were fixed by combined crowns or stabilized by continuous clasp. Methods: Forty patients of Kennedy I dentition defect with loose premolars were collected and divided into 2 groups randomly. Before the restoration with removable partial denture, loose abutments in one group were fixed with combined porcelain fused to metal crowns, while those in the other group were repaired with continuous clasp. Effects of two kinds of treatment were evaluated respectively after 1-5 years follow-up period. Statistic analysis was performed. Results: At 5 years, the success ration of combined porcelain fused to metal crowns group was better than continuous clasp group. The differences of satisfaction rate, plaque control record, probing depth, clinical attachment loss, bleeding on probing and bone support were significant (P<0.05). Conclusion: Good clinical effect of RPD in Kennedy I dentition defect might be obtained after loose abutments were fixed by combined crowns combined with complete periodontal therapy.%目的:分别用烤瓷联冠固定基牙和连续高位卡环稳定基牙,利用可摘局部义齿(removable partial denture,RPD)修复双侧磨牙缺失,比较两者间的临床疗效.方法:选取肯氏Ⅰ类牙列缺损近缺失端基牙I-II度松动病例40例,在进行完善的牙周基础治疗后,分别采用烤瓷联冠固定基牙和连续高位卡环稳定基牙,行可摘局部义齿修复.术后复查,随访1-5年,通过比较患者的主观感受和临床检查结果进行疗效评价.结果:烤瓷联冠组5年临床成功率高于连续高位卡环组,两组患者的满意率、牙周菌斑指数、牙周袋探诊深度、临床附着水平、探诊后出血指数、牙槽骨支持指数差异有统计学意义(P<0.05).结论:对肯氏I类牙列缺损伴前磨牙松动的患牙,经完善的牙周治疗后,烤瓷联冠固定松动

  2. Skin conductance, Marlowe-Crowne defensiveness, and dental anxiety.

    Science.gov (United States)

    Benjamins, C; Schuurs, A H; Hoogstraten, J

    1994-08-01

    The present study assesses the relationship between self-reported dental anxiety (Dental Anxiety Inventory, Dental Anxiety Scale, and Duration of Psychophysiological Fear Reactions), electrodermal activity (skin-conductance level and frequency of spontaneous responses), and Marlowe-Crowne defensiveness. All measurements were made twice. The first session was scheduled immediately before a semi-annual dental check-up (stress condition), and baseline measurements were made two months later without the prospect of a dental appointment. Subjects were male dental patients who regularly attended a university dental clinic and a clinic for Special Dental Care. The main findings were that the low anxious-high defensive-scoring (Marlowe-Crowne Denial subscale) university patients showed significantly higher skin-conductance levels and frequency of nonspecific fluctuations than the low anxious-low defensive-scoring subjects. Besides, the conductance values of the low anxious-high defensive-scoring subjects resembled those of the high anxious-low defensive-scoring patients of the clinic for Special Dental Care, the baseline frequency of nonspecific fluctuations excepted. PMID:7808902

  3. Fracture resistance of monolithic zirconia crowns: The importance of the compressive strength of the dental cements used.

    OpenAIRE

    Lægreid, Solveig Jenssen; Nergård, John Magnus

    2014-01-01

    Background: Monolithic zirconia crowns have not been used for a very long period in dentistry even though zirconia with veneering porcelain, as crown and bridge material has been used for several years with great clinical success. Several different luting materials have been purposed for zirconia but concerning monolithic zirconia the knowledge of the influence of the cement seem to be limited. The aim of the study was to investigate three different cements (one phosphate, one self adhesive a...

  4. Foot posture, leg length discrepancy and low back pain--their relationship and clinical management using foot orthoses--an overview.

    Science.gov (United States)

    Kendall, Julie C; Bird, Adam R; Azari, Michael F

    2014-06-01

    Mechanical low back pain (LBP) is a very common, expensive, and significant health issue in the western world. Functional musculoskeletal conditions are widely thought to cause mechanical low back pain. The role of foot posture and leg length discrepancy in contributing to abnormal biomechanics of the lumbopelvic region and low back pain is not sufficiently investigated. This critical review examines the evidence for the association between foot function, particularly pronation, and mechanical LBP. It also explores the evidence for a role for foot orthoses in the treatment of this condition. There is a body of evidence to support the notion that foot posture, particularly hyperpronation, is associated with mechanical low back pain. Mechanisms that have been put forward to account for this finding are based on either mechanical postural changes or alterations in muscular activity in the lumbar and pelvic muscles. More research is needed to explore and quantify the effects of foot orthoses on chronic low back pain, especially their effects on lumbopelvic muscle function and posture. The clinical implications of this work are significant since foot orthoses represent a simple and potentially effective therapeutic measure for a clinical condition of high personal and social burden.

  5. 改良型牙冠延长术应用于病损达龈下的后牙临床评价%Clinical Evaluation of A Modified Technioue for Surgical Crown Lengthening to the Molars Destroyed Below the Gingiva

    Institute of Scientific and Technical Information of China (English)

    文萍; 安志国; 吴敏; 刘寿桃; 李蕙君

    2011-01-01

    目的 评价改良式牙冠延长术应用于治疗龋坏或劈裂达龈下的后牙的临床效果.方法 7颗龋损或劈裂达龈下的后牙,采用仅降低病损部位牙槽骨高度的方法来恢复丧失的生物学宽度,3个月后全冠修复,定期随访检查牙齿松动度、菌斑指数、牙龈指数和探诊深度.结果 7例患者追踪观察15 ~24个月,平均21.7个月,患牙牙龈健康、美观、稳定.结论 作为传统术式的一种改良,后牙改良式牙冠延长术在满足患区修复学要求的同时,又减少了其他部位由于主动性去骨而造成的不良后果.%Objective To evaluate the clinical effect of a modified technique for surgical crown lengthening implemented the molars destroyed below the gingiva. Methods The alternative to the traditional method involves lowering the height of alveolar bone in the destroyed region to rebuild the biological width. All of these 7 molars,with certain region destroyed below the gingiva by caries or fracture were considered as not suitable for the traditional prosthetics methods. They were treated by this modified method of surgical crown lengthening. Restoration was accomplished on these teeth three month later. Periodontal index such as tooth mobility,plaque index,probing depth and bleeding index were recor-ded and followed up for more than 15 months. Results The mean follow-up period was 21.7 months (ranged from 15 to 24 months). Result of surgery and restoration of these 7 teeth was satisfactory. The gingival tissue remained healthy and esthetic with good function. Conclusion As an alternative to the traditional method,this modified surgical crown lengthening can not only meet the demand of prosthetics in the destroyed region,but also reduce the negative consequences for excessive lowering the bone height in the other region.

  6. A retrospective clinical, radiographic and microbiological study of periodontal conditions of teeth with and without crowns Um estudo retrospectivo clínico, radiográfico e microbiológico das condições periodontais de dentes com e sem coroas

    Directory of Open Access Journals (Sweden)

    Marcio Dias Giollo

    2007-12-01

    Full Text Available The aim of this study was to evaluate retrospectively the periodontal conditions of teeth with fixed crowns that had been in place from 3 to 5 years before the study was conducted. Forty individuals were recalled for a follow-up visit. Full-mouth clinical examinations were carried out and Visible Plaque Index (VPI, Gingival Bleeding Index (GBI, Probing Pocket Depth (PPD, and clinical attachment level (CAL were assessed in 6 sites per tooth. Parallel radiographs were also taken and blindly analyzed by a digital caliper (distance between the apex and the bone crest. BANA tests were performed. A contra-lateral sound tooth was considered the control. Mean values were obtained and Wilcoxon and paired sample t tests were used to compare the test and control sites. Crowns had a mean VPI value of 30.42% as compared to 49.17% for sound teeth. The GBI was 33.33% and 26.25% for test and control teeth respectively. Assessment of PPD revealed values of 2.30 and 2.14 mm, and assessment of CAL revealed averages of 2.02 and 1.89 mm for test and control teeth respectively. The mean values for radiographic distances were 12.73 and 13.67 mm, and for the BANA test, 67.50 and 50.00 for sound and crowned teeth, respectively. Statistically significant differences were observed for all parameters except for CAL and for the BANA test. It may be concluded that, with the methods used in the present study, crowns may be associated with more signs of inflammation, however not with periodontal breakdown.O objetivo deste estudo foi avaliar retrospectivamente as condições periodontais de pacientes com coroas fixas colocadas de 3 a 5 anos antes da realização da pesquisa. Quarenta indivíduos foram rechamados. Exames clínicos de toda a boca foram realizados avaliando-se Índice de Placa Visível (IPV, Índice de Sangramento Gengival (ISG, Profundidade de Sondagem (PS e Nível Clínico de Inserção (NCI em 6 sítios por dente. Radiografias paralelas foram obtidas e

  7. A Comparative Evaluation for Biologic Width following Surgical Crown Lengthening Using Gingivectomy and Ostectomy Procedure

    Directory of Open Access Journals (Sweden)

    Kiran Kumar Ganji

    2012-01-01

    Full Text Available Surgical crown lengthening has been proposed as a means of facilitating restorative procedures and preventing injuries in teeth with structurally inadequate clinical crown or exposing tooth structure in the presence of deep, subgingival pathologies which may hamper the access for proper restorative measures. Histological studies utilizing animal models have shown that postoperative crestal resorption allowed reestablishment of the biologic width. However, very little has been done in humans. Aims. The purpose of the study was to evaluate the potential changes in the periodontal tissues, particularly the biologic width, following surgical crown lengthening by two surgical procedures before and after crown placement. Methods and Material. Twenty (20 patients who needed surgical crown lengthening to gain retention necessary for prosthetic treatment and/or to access caries, tooth fracture, or previous prosthetic margins entered the study. The following parameters were obtained from line angles of treated teeth (teeth requiring surgical crown lengthening and adjacent sites: Plaque and Gingival Indices (PI & (GI, Position of Gingival Margin from reference Stent (PGMRS, Probing depth (PD, and Biologic Width (BW. Statistical Analysis Used. Student “t” Test. Results. Initial baseline values of biologic width were 2.55 mm (Gingivectomy procedure B1 Group and 1.95 mm (Ostectomy procedure B2 Group and after surgical procedure the values were 1.15 mm and 1.25 mm. Conclusions. Within the limitations of the study the biologic width, at treated sites, was re-established to its original vertical dimension by 3 months. Ostectomy with apically positioned flap can be considered as a more effective procedure than Gingivectomy for Surgical Crown Lengthening.

  8. A Comparative Evaluation for Biologic Width following Surgical Crown Lengthening Using Gingivectomy and Ostectomy Procedure.

    Science.gov (United States)

    Ganji, Kiran Kumar; Patil, Veena Ashok; John, Jiji

    2012-01-01

    Surgical crown lengthening has been proposed as a means of facilitating restorative procedures and preventing injuries in teeth with structurally inadequate clinical crown or exposing tooth structure in the presence of deep, subgingival pathologies which may hamper the access for proper restorative measures. Histological studies utilizing animal models have shown that postoperative crestal resorption allowed reestablishment of the biologic width. However, very little has been done in humans. Aims. The purpose of the study was to evaluate the potential changes in the periodontal tissues, particularly the biologic width, following surgical crown lengthening by two surgical procedures before and after crown placement. Methods and Material. Twenty (20) patients who needed surgical crown lengthening to gain retention necessary for prosthetic treatment and/or to access caries, tooth fracture, or previous prosthetic margins entered the study. The following parameters were obtained from line angles of treated teeth (teeth requiring surgical crown lengthening) and adjacent sites: Plaque and Gingival Indices (PI) & (GI), Position of Gingival Margin from reference Stent (PGMRS), Probing depth (PD), and Biologic Width (BW). Statistical Analysis Used. Student "t" Test. Results. Initial baseline values of biologic width were 2.55 mm (Gingivectomy procedure B1 Group) and 1.95 mm (Ostectomy procedure B2 Group) and after surgical procedure the values were 1.15 mm and 1.25 mm. Conclusions. Within the limitations of the study the biologic width, at treated sites, was re-established to its original vertical dimension by 3 months. Ostectomy with apically positioned flap can be considered as a more effective procedure than Gingivectomy for Surgical Crown Lengthening.

  9. 牙冠延长术结合少量去骨在保存斜折上颌第一磨牙中的临床应用%Clinical Application of Crown Lengthening Combined with a Small Amount of Alveolectomy Preserved Oblique Odontagma Maxillary First Molar.

    Institute of Scientific and Technical Information of China (English)

    赵峰; 陈红亮; 孙勇

    2011-01-01

    Objective: To explore the clinical application of oblique odontagma molar preservation.Methods:Crown lengthening combined with a small amount of alveolectomy and trimmed gum forman approach to restore the lost biological width as a result of oblique odontagma.Repair material with good biocompatibility was used to restore function.Both tooth mobility and periodontal pocket depth were periodically reviewed.The patients were kept track of for more than 6 months and the results were recorded.Results: 10 patients were tracked for 12 months,with one case of failure and 9 cases of well preserved teeth.Conclusion: Crown lengthening combined with a small amount of alveolectomy can restore biological width, safeguarding the integrity of the dentition.%目的:探索保存斜折磨牙的保存方法.方法:采用牙冠延长术并结合少量去骨,修整牙龈形态的方法来恢复由于牙折丧失的生物学宽度.采用生物相容性好的修复材料恢复功能,定期复查牙松动度及牙周袋深度,追踪6个月以上并记录结果.结果:10例患者追踪12个月,1例失败,9例患牙良好.结论:牙冠延长术结合少量去骨能有效恢复重建斜折磨牙丧失的生物学宽度,维护牙列的完整性.

  10. An update on crown lengthening. Part 1: Gingival tissue excess.

    Science.gov (United States)

    Kalsi, Harpoonam Jeet; Hussain, Zahra; Darbar, Ulpee

    2015-03-01

    This is the first article in a two-part series which aims to provide an overview of the different techniques used to increase clinical crown height. In the first paper, the focus will be on the management of patients who present with gingival tissue excess. The different aetiologies are discussed and illustrated with clinical cases, following which a range of procedures that may be employed in the management of these patients are presented. With an increasingly ageing population, more patients are taking regular medications prescribed from their general medical practitioner, and so having a working knowledge of the specific drugs that may cause gingival enlargement is essential. Clinical Relevance: When patients with gingival tissue excess present in primary or secondary care, a clinician must have a good knowledge of the possible causes of the condition, as well as an idea of how the patient may be managed.

  11. Zirconia Crown as Single Unit Tooth Restoration: A Literature Review.

    Science.gov (United States)

    Alfawaz, Yasser

    2016-01-01

    Ceramics has become increasingly popular as a dental restorative material because of its superior esthetics, as well as its inertness and biocompatibility. Among dental ceramics, zirconia is used as a dental biomaterial and it is the material of choice in contemporary restorative dentistry. Zirconia ceramics has both clinical popularity and success due to its outstanding mechanical properties and ease of machining in the green stage via computer-aided design and computer-aided manufacturing technology. Zirconia is one of the most promising restorative biomaterial because it has favorable mechanical and chemical properties suitable for medical application. Zirconia ceramics is becoming a prevalent biomaterial in dentistry. Clinical evaluations also indicate a good success rate for zirconia with minimal complications. This article reviews the current literature on dental zirconia with respect to basic properties, biocompatibility, and clinical applications in aesthetic dentistry as single unit crown. PMID:27443370

  12. Multidisciplinary Approach to the Management of Complicated Crown-Root Fracture: A Case Report

    Science.gov (United States)

    Bajaj, Pavan; Chordiya, Rashmi; Rudagi, Kavitarani; Patil, Nitin

    2015-01-01

    Oblique crown-root fracture in the cervical third of the root is a common event following trauma to the anterior region of the mouth. As a result, sound tooth structure coronal to the attachment apparatus may not be available for restorative needs. Invasion of biological width by fracture line presents a clinical challenge in restorative planning. Placing a restoration margin on sound tooth structure within the dentogingival biological width might result in violation of biological width and should be considered a restorative failure. Maintaining a healthy periodontal attachment apparatus is crucial for long term prognosis and esthetics of the restored tooth. Surgical crown lengthening, surgical extrusion or orthodontic extrusions are the few alternative modalities to expose the fracture line. This case presentation demonstrates a predictable solution in overcoming an oblique crown-root fracture caused by trauma during a road accident. Orthodontic extrusion was used to elevate the fractured tooth from within the alveolar socket to allow the placement of crown margins on sound tooth structure without harming the biologic width. Combining fiberotomy with the extrusion procedure in this case eliminated the need for the surgical procedure. This allowed proper fabrication of post and core and the placement of the crown on sound tooth structure, fulfilling the biological and mechanical principles including obligatory ferrule effect. PMID:25954080

  13. Accuracy of Digital Impressions and Fitness of Single Crowns Based on Digital Impressions

    Directory of Open Access Journals (Sweden)

    Xin Yang

    2015-06-01

    Full Text Available In this study, the accuracy (precision and trueness of digital impressions and the fitness of single crowns manufactured based on digital impressions were evaluated. #14-17 epoxy resin dentitions were made, while full-crown preparations of extracted natural teeth were embedded at #16. (1 To assess precision, deviations among repeated scan models made by intraoral scanner TRIOS and MHT and model scanner D700 and inEos were calculated through best-fit algorithm and three-dimensional (3D comparison. Root mean square (RMS and color-coded difference images were offered. (2 To assess trueness, micro computed tomography (micro-CT was used to get the reference model (REF. Deviations between REF and repeated scan models (from (1 were calculated. (3 To assess fitness, single crowns were manufactured based on TRIOS, MHT, D700 and inEos scan models. The adhesive gaps were evaluated under stereomicroscope after cross-sectioned. Digital impressions showed lower precision and better trueness. Except for MHT, the means of RMS for precision were lower than 10 μm. Digital impressions showed better internal fitness. Fitness of single crowns based on digital impressions was up to clinical standard. Digital impressions could be an alternative method for single crowns manufacturing.

  14. A Review of the Positive Influence of Crown Contours on Soft-Tissue Esthetics.

    Science.gov (United States)

    Kinsel, Richard P; Pope, Bryan I; Capoferri, Daniele

    2015-05-01

    Successful crown restorations duplicate the natural tooth in hue, chroma, value, maverick colors, and surface texture. Equally important is the visual harmony of the facial and proximal soft-tissue contours, which requires the collaborative skills of the restorative dentist, periodontist, and dental technician. The treatment team must understand the biologic structures adjacent to natural dentition and dental implants. This report describes the potential for specifically designed restorative contours to dictate the optimal gingival profile for tooth-supported and implant-supported crowns. Showing several cases, the article explains how esthetic soft-tissue contours enhance the definitive crown restoration, highlights the importance of clinical evaluation of adjacent biologic structures, and discusses keys to predicting when the proximal papilla has the potential to return to a favorable height and shape. PMID:26053638

  15. Evaluation of the Effect of Surgical Crown Lengthening on Periodontal Parameters

    Directory of Open Access Journals (Sweden)

    Farzane Vaziri

    2015-09-01

    Full Text Available Background: Surgical crown lengthening is needed for teeth with subgingival caries, fractured teeth, insufficient crown length, and deep subgingival margin of failed restorations. Since there is no agreement on the effects of crown lengthening surgery on gingival parameters, the purpose of this study was to evaluate periodontal parameters in patients who needed crown lengthening surgery. Methods: Twenty patients who had healthy periodontium and needed surgical crown lengthening were included in this study. After professional dental cleaning, gingival parameters including gingival index (GI, probing depth (PD, bone level (BL, and transsulcular probing (TSP were recorded in interproximal and keratinized gingiva (KG in mid buccal portion. The patients were evaluated one and three months after the surgery. Results: After one and three months of the surgery, the amount of PD reduced from 2.32 mm to 1.25 mm and 1.17 mm, respectively (P=0.001. The mean of BL reduction was 0.88 mm after one month (P=0.001, but there was no reduction between 1 month and 3 months. Amounts of KG at baseline andone month later were 4.2 mm and 2.9 mm, respectively (P=0.001, and remained at the same level up to three months. TSP significantly reduced (from 3.67 mm at baseline to 2.62 mm after 1 month, and to 2.27 mm after 3 months (P=0.001, P=0.005. Conclusion: The present  study suggests that in the presence of good oral hygiene, except BW (biological width, other parameters including PD, BL, KG, and TSP had significant changes after crown lengthening surgery in the period of 1 month and 3 months (P

  16. EL CROWN HALL. CONTEXTO Y PROYECTO

    Directory of Open Access Journals (Sweden)

    Laura Lizondo Sevilla

    2010-05-01

    Full Text Available RESUMEN El artículo enmarca el edificio del Crown Hall en el contexto docente y arquitectónico de Mies van der Rohe. Revisa sus inicios en la Bauhaus con su primera intervención en un espacio docente para la Bauhaus de Berlín en 1932, así como su marcha a Estados Unidos, los planteamientos arquitectónicos del campus del IIT y el proyecto del Crown Hall. El texto incide en el estudio del proceso proyectual del Crown Hall analizando la evolución de su concepción arquitectónica a través de las diferentes versiones del proyecto. Se constata la transición desde los primeros planteamientos arquitectónicos de los edificios del campus del IIT proyectados por Mies hacia el planteamiento del gran espacio unitario del Crown Hall. Este proyecto se puede entender desde la creciente importancia de la estructura, la claridad constructiva y el manejo del acero y vidrio como únicos materiales de la imagen del edificio y el carácter flexible y unitario del espacio. Finalmente se hace referencia al concepto del "espacio universal" en la arquitectura de Mies, como un concepto abstracto que supera los de flexibilidad de uso o unidad espacial, insinuando, a modo de reflexión, las principales variables que definirían el espacio universal miesiano.SUMMARY The article showcases the Crown Hall building in the educational and architectural context of Mies van der Rohe. It reviews his beginnings in the Bauhaus with his first intervention in an educational space for the Bauhaus of Berlin in 1932, as well as his sojourn to the United States, and the architectural approaches to the IIT campus and the Crown Hall project. The text touches on the study of the planning process for the Crown Hall, analysing the evolution of its architectural conception, through the different versions of the project. The article covers the transition from the first architectural approaches for the IIT campus buildings, planned by Mies, to the approach of the large unitary space of

  17. Treatment of crown dilaceration: An interdisciplinary approach

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    Subramaniam P

    2010-03-01

    Full Text Available Trauma to primary teeth can result in a wide range of disturbances to the underlying permanent teeth, such as dilaceration. Root dilacerations occur more commonly than crown dilacerations. This paper is a report of an 11-year-old girl with a missing maxillary left anterior tooth. Past history revealed premature loss of primary maxillary anterior teeth due to trauma. Radiographic examination revealed crown dilaceration of permanent maxillary left central incisor. An interdisciplinary approach in the management of this child is presented herewith.

  18. Subtype-independent near full-length HIV-1 genome sequencing and assembly to be used in large molecular epidemiological studies and clinical management

    Directory of Open Access Journals (Sweden)

    Sebastian Grossmann

    2015-06-01

    Full Text Available Introduction: HIV-1 near full-length genome (HIV-NFLG sequencing from plasma is an attractive multidimensional tool to apply in large-scale population-based molecular epidemiological studies. It also enables genotypic resistance testing (GRT for all drug target sites allowing effective intervention strategies for control and prevention in high-risk population groups. Thus, the main objective of this study was to develop a simplified subtype-independent, cost- and labour-efficient HIV-NFLG protocol that can be used in clinical management as well as in molecular epidemiological studies. Methods: Plasma samples (n=30 were obtained from HIV-1B (n=10, HIV-1C (n=10, CRF01_AE (n=5 and CRF01_AG (n=5 infected individuals with minimum viral load >1120 copies/ml. The amplification was performed with two large amplicons of 5.5 kb and 3.7 kb, sequenced with 17 primers to obtain HIV-NFLG. GRT was validated against ViroSeqTM HIV-1 Genotyping System. Results: After excluding four plasma samples with low-quality RNA, a total of 26 samples were attempted. Among them, NFLG was obtained from 24 (92% samples with the lowest viral load being 3000 copies/ml. High (>99% concordance was observed between HIV-NFLG and ViroSeqTM when determining the drug resistance mutations (DRMs. The N384I connection mutation was additionally detected by NFLG in two samples. Conclusions: Our high efficiency subtype-independent HIV-NFLG is a simple and promising approach to be used in large-scale molecular epidemiological studies. It will facilitate the understanding of the HIV-1 pandemic population dynamics and outline effective intervention strategies. Furthermore, it can potentially be applicable in clinical management of drug resistance by evaluating DRMs against all available antiretrovirals in a single assay.

  19. Validation of Transient Elastography and Comparison with Spleen Length Measurement for Staging of Fibrosis and Clinical Prognosis in Primary Sclerosing Cholangitis

    Science.gov (United States)

    Ehlken, Hanno; Wroblewski, Raluca; Corpechot, Christophe; Arrivé, Lionel; Rieger, Tim; Hartl, Johannes; Lezius, Susanne; Hübener, Peter; Schulze, Kornelius; Zenouzi, Roman; Sebode, Marcial; Peiseler, Moritz; Denzer, Ulrike W.; Quaas, Alexander; Weiler-Normann, Christina; Lohse, Ansgar W.; Chazouilleres, Olivier; Schramm, Christoph

    2016-01-01

    Background Patients with primary sclerosing cholangitis (PSC) develop progressive liver fibrosis and end-stage liver disease. Non-invasive and widely available parameters are urgently needed to assess disease stage and the risk of clinical progression. Transient elastography (TE) has been reported to predict fibrosis stage and disease progression. However, these results have not been confirmed in an independent cohort and comparison of TE measurement to other non-invasive means is missing. Methods In a retrospective study we collected data from consecutive PSC patients receiving TE measurements from 2006 to 2014 (n = 139). Data from 62 patients who also underwent a liver biopsy were used to assess the performance of TE and spleen length (SL) measurement for the staging of liver fibrosis. Follow-up data from this cohort (n = 130, Hamburg) and another independent cohort (n = 80, Paris) was used to compare TE and SL as predictors of clinical outcome applying Harrel’s C calculations. Results TE measurement had a very good performance for the diagnosis and exclusion of higher fibrosis stages (≥F3: AUROC 0.95) and an excellent performance for the diagnosis and exclusion of cirrhosis (F4 vs. < F4: AUROC 0.98). Single-point TE measurement had very similar predictive power for patient outcome as previously published. In a combined cohort of PSC patients (n = 210), SL measurements had a similar performance as TE for the prediction of patient outcome (5 x cross-validated Harrel’s C 0.76 and 0.72 for SL and TE, respectively). Conclusions Baseline TE measurement has an excellent performance to diagnose higher fibrosis stages in PSC. Baseline measurements of SL and TE have similar usefulness as predictive markers for disease progression in patients with PSC. PMID:27723798

  20. Clinical results of large defect teeth or flared roots restored by fiber posts and resin composites core in combination with full crowns%纤维桩核冠修复牙体严重缺损的临床效果观察

    Institute of Scientific and Technical Information of China (English)

    王贯新; 白保晶; 魏永杰

    2011-01-01

    目的 观察纤维桩树脂核全冠修复牙体严重缺损和薄弱根管的临床修复效果.方法 选择牙体大面积缺损和薄弱根管患者165例219个患牙为研究对象.患牙经根管治疗后行纤维桩树脂核伞冠修复,修复完成后6个月、1年、2年进行临床复查,其中牙体缺损达龈下行牙龈切除术或冠延长术的患牙,增加修复后1个月和3个月临床复查,评价其临床修复效果.结果 165例的219个患牙中,有4例出现纤维桩与根管壁完整脱落,均未见根折、根裂,重新粘固后未见异常.其余215个患牙修复体未出现脱落,冠边缘密合,牙周正常,219个患牙均未出现基牙松动.结论 应用纤维桩树脂核全冠修复牙体严重缺损和薄弱根管可以达到满意的临床修复效果.%Objective To observe the clinical results of fiber post and resin composite core for the repair of large defect teeth or flared roots. Methods A total of 219 large defect teeth or flared roots from 165 patients were restored by fiber posts and resin composite core as well as full crowns. The clinical results of the restorations were followed up for a minimum of six months. Results Four of the 219 restorations failed but the roots remained intact and re-bonded with the previous post-and-core crowns. The restorations and periodontal tissues of the other 215 teeth were normal and successful. Conclusion Fiber post and resin composite core system is reliable for restoring large defect teeth or flared roots with satisfactory clinical results.

  1. Fracture resistance of monolithic zirconia molar crowns with reduced thickness

    OpenAIRE

    Nakamura, Keisuke; Harada, A.; Inagaki, R.; Kanno, Taro; Niwano, Y; Milleding, Percy; Ørtengren, Ulf Thore

    2015-01-01

    Objectives. The purpose of the present study was to analyze the relationship between fracture load of monolithic zirconia crowns and axial/occlusal thickness, and to evaluate the fracture resistance of monolithic zirconia crowns with reduced thickness in comparison with that of monolithic lithium disilicate crowns with regular thickness. Materials and methods. Monolithic zirconia crowns (Lava Plus Zirconia, 3M/ESPE) with specified axial/occlusal thicknesses and lithium disilica...

  2. Cambios dimensionales de los tejidos en los procedimientos de alargamiento coronario Dimensional changes in tissues after crown lengthening procedures

    Directory of Open Access Journals (Sweden)

    C. Álvarez-Novoa García

    2012-08-01

    : We performed a search in PubMed with the keyword "crown lengthening", limited to English language articles, that were published between the years 1990-2009, which were clinical trials. The recovery of documents was held in the periodicals of the Faculty of Dentistry in UCM, and in Compludoc database. Two evaluators reviewed the papers individually. Results and Discussion: The seven articles, including studies in both animals and humans, which were included in the review, analyzing gingival index, bone level, probing depth, attachment level and biological width, and crown length and the position of the gingival margin. Conclusions: Bone level is altered during the first 3 months, but thereafter remains constant. The longer-term studies found no significant differences in bone probing depth at 6 and 12 months after the surgery.

  3. Clinically Significant Contrast Induced Acute Kidney Injury after Non-Emergent Cardiac Catheterization - Risk Factors and Impact on Length of Hospital Stay

    International Nuclear Information System (INIS)

    Objective: To evaluate the frequency and risk factors associated with clinically significant contrast-induced nephropathy (CIN) in patients undergoing non-emergent coronary angiography. Study Design: Descriptive study. Place and Duration of Study: The Aga Khan University Hospital, Karachi, from January 2005 to December 2007. Methodology: Case records of patients who underwent coronary angiography with a serum creatinine of >= 1.5 mg/dl at the time of procedure were evaluated. Clinically significant contrast induced nephropathy (CSCIN) was defined as either doubling of serum creatinine from baseline value within a week following the procedure or need for emergency hemodialysis after the procedure. Results: One hundred and sixteen patients met the inclusion criteria. Mean age was 64.0 +- 11.5 years, 72% were males. Overall prevalence of CIN was 17% (rise of serum creatinine by A= 0.5 mg/dl) while that of clinically significant CIN (CSCIN) was 9.5% (11 patients). Patients with CSCIN had significantly lower left ventricular ejection fraction (p = 0.03, OR: 0.24; 95% CI = 0.06 A= 0.91) and higher prevalence of cerebrovascular disease (p < 0.001, OR: 14.66; 95% CI = 3.30 - 65.08). Mean baseline serum creatinine was significantly higher, 3.0 +- 1.5 vs. 2.0 +- 1.1 mg/dl (p = 0.03, OR: 1.47; 95% CI = 1.03 - 2.11) whereas mean GFR estimated by Cockcroft-Gault formula was significantly lower at 25 +- 7.4 vs. 41.0 +- 14.6 ml/minute (p = 0.001, OR = 0.89, 95% CI = 0.84 A= 0.95) at the time of procedure in patients with CSCIN. Mean length of hospital stay was significantly higher in this group compared to those without CIN, 9.0 +- 5.1 vs. 3.0 +- 3.2 days (p = 0.001, OR = 1.31, 95% CI = 1.12 - 1.54). Multivariate analysis revealed low GFR (p = 0.001, OR = 0.88; 95% CI = 0.82 - 0.95) and low ejection fraction (p = 0.03, OR = 0.20; 95% CI = 0.04 - 0.91) to be independent factors associated with CSCIN. No significant differences were noted between the two groups in patients with

  4. Finkelstein Reaction in Functionalized Crown-ether Ionic Liquids

    Institute of Scientific and Technical Information of China (English)

    Xiao Hua WANG; Han Zhi WANG; Hui LIU; Yuan KOU

    2006-01-01

    Functional crown-ether ionic liquids were used as catalytic green solvents of Finkelstein reaction of 1-bromooctane and iodide. The rate and yield of the reaction were obvious improved compared with that using crown ether in water. No free crown ether loss was observed after reaction.

  5. Evaluation of wild juglans species for crown gall resistance

    Science.gov (United States)

    A. tumefaciens is a soil-borne Gram-negative bacterium which causes crown gall on many dicotyledonous plant species including walnut. Crown gall symptoms on walnut are characterized by large tumors located near the crown of the tree but can occur near wounds caused by bleeding cuts or at the graft u...

  6. 21 CFR 872.3770 - Temporary crown and bridge resin.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Temporary crown and bridge resin. 872.3770 Section... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3770 Temporary crown and bridge resin. (a) Identification. A temporary crown and bridge resin is a device composed of a material, such...

  7. Branch architecture, light interception and crown development in saplings of a plagiotropically branching tropical tree, Polyalthia jenkinsii (Annonaceae).

    Science.gov (United States)

    Osada, Noriyuki; Takeda, Hiroshi

    2003-01-01

    To investigate crown development patterns, branch architecture, branch-level light interception, and leaf and branch dynamics were studied in saplings of a plagiotropically branching tree species, Polyalthia jenkinsii Hk. f. & Thoms. (Annonaceae) in a Malaysian rain forest. Lengths of branches and parts of the branches lacking leaves ('bare' branches) were smaller in upper branches than in lower branches within crowns, whereas lengths of 'leafy' parts and the number of leaves per branch were larger in intermediate than in upper and lower branches. Maximum diffuse light absorption (DLA) of individual leaves was not related to sapling height or branch position within crowns, whereas minimum DLA was lower in tall saplings. Accordingly, branch-level light interception was higher in intermediate than in upper and lower branches. The leaf production rate was higher and leaf loss rate was smaller in upper than in intermediate and lower branches. Moreover, the branch production rate of new first-order branches was larger in the upper crowns. Thus, leaf and branch dynamics do not correspond to branch-level light interception in the different canopy zones. As a result of architectural constraints, branches at different vertical positions experience predictable light microenvironments in plagiotropic species. Accordingly, this pattern of carbon allocation among branches might be particularly important for growth and crown development in plagiotropic species. PMID:12495920

  8. Recommendations for conducting controlled clinical studies of dental restorative materials. Science Committee Project 2/98--FDI World Dental Federation study design (Part I) and criteria for evaluation (Part II) of direct and indirect restorations including onlays and partial crowns.

    Science.gov (United States)

    Hickel, Reinhard; Roulet, Jean-François; Bayne, Stephen; Heintze, Siegward D; Mjör, Ivar A; Peters, Mathilde; Rousson, Valentin; Randall, Ros; Schmalz, Gottfried; Tyas, Martin; Vanherle, Guido

    2007-01-01

    About 35 years ago, Ryge provided a practical approach to the evaluation of the clinical performance of restorative materials. This systematic approach was soon universally accepted. While that methodology has served us well, a large number of scientific methodologies and more detailed questions have arisen that require more rigor. Current restorative materials have vastly improved clinical performance, and any changes over time are not easily detected by the limited sensitivity of the Ryge criteria in short-term clinical investigations. However, the clinical evaluation of restorations not only involves the restorative material per se but also different operative techniques. For instance, a composite resin may show good longevity data when applied in conventional cavities but not in modified operative approaches. Insensitivity, combined with the continually evolving and nonstandard investigator modifications of the categories, scales, and reporting methods, has created a body of literature that is extremely difficult to interpret meaningfully. In many cases, the insensitivity of the original Ryge methods leads to misinterpretation as good clinical performance. While there are many good features of the original system, it is now time to move on to a more contemporary one. The current review approaches this challenge in two ways: (1) a proposal for a modern clinical testing protocol for controlled clinical trials, and (2) an in-depth discussion of relevant clinical evaluation parameters, providing 84 references that are primarily related to issues or problems for clinical research trials. Together, these two parts offer a standard for the clinical testing of restorative materials/procedures and provide significant guidance for research teams in the design and conduct of contemporary clinical trials. Part 1 of the review considers the recruitment of subjects, restorations per subject, clinical events, validity versus bias, legal and regulatory aspects, rationales for

  9. Engineering properties and performance of dental crowns.

    Science.gov (United States)

    Mitchell, C A; Orr, J F

    2005-07-01

    Dental crowns are used to replace damaged natural crowns of teeth and are fixed to prepared teeth with luting cements, which should provide an adhesive bond to the tooth structure giving reliable retention and minimal microleakage. Mechanical testing of crowns in vitro gives failure load distributions that are well described by Weibull models, comparing probabilities of survival and reliability. Fatigue testing of crowns is time consuming, but regression analysis to interpolate functions through data points quoting probability limits or applying Weibull analysis is achievable. A complementary approach is to conduct materials tests with appropriate interfacial geometries. Luting cements are used in thin layers of 40-150 microm. Contraction during polymerization is restrained by adhesion to substrates, allowing little relaxation of stresses. Conventional and resin-modified glass ionomer cements create thin zones of interaction with dentine and fail cohesively. The chevron notch short rod technique has been used to measure fracture toughness and rank cements. A development of this method, using chevron notch short bar specimens, permitted fracture toughness to be determined for luting cement--dentine substrate interfaces. Representative fracture experiments need to be developed to apply mixed mode conditions. The basic challenge to predict long-term performance from short-term laboratory tests remains.

  10. Everbearing strawberry cultivars - susceptibility to crown rot

    OpenAIRE

    Parikka, Päivi; Karhu, Saila; Hietaranta, Tarja

    2009-01-01

    Studies on the production of everbearing strawberry cultivars were started at MTT Plant Production Research in 2007. MTT Horticulture makes trials in tunnel and open fields to study the growth, yield and overwintering of cultivars in northern conditions. Resistance to crown rot is also being tested.

  11. Solvent Effects on Cesium Complexation with Crown Ethers from Liquid to Supercritical Fluids

    International Nuclear Information System (INIS)

    Nuclear magnetic resonance (NMR) techniques were used to study crown ether-water interactions in solvents of low dielectric constants such as chloroform and carbon tetrachloride. Water forms a 1:1 complex with a number of crown ethers including 12-crown-4, 15-crown-5, 18-crown-6, dicyclohexano-18=crown-6, dicyclohexano-24-crown 8, and dibenzl-24-crown-8 in chloroform. Among these crown ethers, the 18-crown-6-H2 complex has the largest equilibrium constant (K=545) and 97% of the crown is complexed to water in chloroform. Addition of carbon tetrachloride to chloroform lowers the equilibrium constants of the crown-water complexes. The partition coefficients of crown ethers (D=crown in water/crown in solvent) between water and organic solvent also vary with solvent composition

  12. 镍铬合金烤瓷牙的肾毒性:理论研究与临床验证%Renal toxicity of dental porcelain crown containing Ni-Cr alloy: Theoretical study and clinical verification

    Institute of Scientific and Technical Information of China (English)

    樊灿灿; 宁静; 孟松; 李应龙; 彭鹏; 刘斌

    2010-01-01

    背景:镍铬合金烤瓷牙是广泛应用于临床的修复体,对其安全性的争论通常限于口腔及邻近组织器官,而与全身范围内疾病如肾中毒的关联性尚未被重视.目的:分析镍铬合金烤瓷牙导致肾病的可能性及长期应用临床的安全性.方法:以"镍铬合金,烤瓷牙,肾中毒"为中文检索词,以"nickle chromium alloy,porcelain crown,nephridium toxicosis"为英文检索词,采用计算机检索1989-01/2009-10维普中文科技期刊数据库、中国CNKI学术总库、万方数据库、中国生物医学文献数据库、Biosis Previews数据库及BioOne生物全文期刊数据库相关文献.纳入与镍铬合金烤瓷牙及金属离子毒性相关研究,排除重复研究.结果与结论:通过查阅国内外文献,文章从镍铬合金的腐蚀性及其在口腔和全身范围的蓄积和影响,镍铬烤瓷合金在体内所释放金属元素及其衍生物的直接毒性和肾中毒的易感性,以及镍铬离子造成肾脏损害的可能途径几方面分析了镍铬合金烤瓷牙的重金属离子腐蚀、扩散以及导致肾中毒的可能性,为进一步研究镍铬合金烤瓷牙的安全性提供依据.

  13. Internal adaptation of cast titanium crowns

    Directory of Open Access Journals (Sweden)

    Sicknan Soares da Rocha

    2007-08-01

    Full Text Available As the adaptation of titanium crowns obtained by Rematitan Plus investment, specific for titanium, is not recognized to be suitable, this study evaluated the effect of the concentration of the specific liquid and the temperature of the mold of investments on the internal misfit of crowns cast on commercially pure titanium. Individual dies of epoxy resin were obtained, representing teeth prepared for full-crown restoration with a 6-degree axial surface convergence angle and shoulder (1.0 mm. For the waxing of each crown, a ring-shaped stainless steel matrix (8.0mm internal diameter; 7.5 mm height was adapted above the individual dies of epoxy resin. The Rematian Plus investment was mixed according to the manufacturer's instructions using two different concentrations of the specific liquid: 100%, 75%. Casting was performed in a Discovery Plasma Ar-arc vacuum-pressure casting machine with molds at temperatures of 430ºC, 515ºC and 600ºC. The crowns were cleaned individually in a solution (1% HF + 13% HNO3 for 10 min using a ultrasonic cleaner, with no internal adaptations, and luted with zinc phosphate cement under a 5 kg static load. The crown and die assemblies were embedded in resin and sectioned longitudinally. The area occupied by cement was observed using stereoscopic lens (10X and measured by the Leica Qwin image analysis system (mm². The data for each experimental condition (n=8 were analyzed by Kruskal-Wallis non-parametric test (á=0.05. The results showed that liquid dilution and the increase in mold temperature did not significantly influence the levels of internal fit of the cast titanium crowns. The lowest means (±SD of internal misfit were obtained for the 430ºC/100%: (7.25 mm² ±1.59 and 600ºC/100% (8.8 mm² ±2.25 groups, which presented statistically similar levels of internal misfit.

  14. 牙冠延长术临床应用及牙龈缘短期内位置变化观察%Clinical application of crown lengthening surgery and the change of gingiva margin position initial study in a short time

    Institute of Scientific and Technical Information of China (English)

    王如; 李秋红; 罗蓉

    2013-01-01

    目的:观察以生物学宽度为原则的改良牙冠延长术临床效果以及术后短期内牙龈缘位置变化的情况。方法收集17例行牙冠延长术患者22颗患牙的临床资料,对比观察术前及术后牙龈健康状况,牙龈缘位置变化情况、前牙美观效果。结果14例19颗牙齿患者主观评价良好,患牙无松动、叩痛,牙龈无炎症,X线片影像无异常。牙龈缘位置在术后1周为轻度水肿位于预期位置的冠方;在术后4周,6周龈缘位置稳定健康位于预期位置。结论以生物学宽度为基准开展的改良牙冠延长术能满足修复的要求及牙龈的稳定和健康,同时可以满足美观的需求。%Objective To observe the clinic result of crown lengthening surgery by the biological principle and the location -al change of gingival margin .Methods We collected the clinic dates of 17 cases 22 teeth and compared with the sanitary condition and the location of gingival margin between dates of pre -surgery and post -surgery.Results For 14 cases 19 teeth the subjective evaluation was well , the degree of tooth mobilization was normal , touching tooth showed no pain , it was no gingival infection and X -ray picture showed no abnormal image .The location of the gingival margin showed a little edematous at 1 week pose-surgery;at 4 week and 6 week post -surgery, the location of the gingival margin showed the prospective site .Conclusion The crown lengthening surgery by biological width principle could get stable location of gingi -val margin and health , simultaneously , it could meet the demand of aesthetics .

  15. Clinical impact of antimicrobial resistance in European hospitals: excess mortality and length of hospital stay related to methicillin-resistant Staphylococcus aureus bloodstream infections.

    LENUS (Irish Health Repository)

    de Kraker, Marlieke E A

    2011-04-01

    Antimicrobial resistance is threatening the successful management of nosocomial infections worldwide. Despite the therapeutic limitations imposed by methicillin-resistant Staphylococcus aureus (MRSA), its clinical impact is still debated. The objective of this study was to estimate the excess mortality and length of hospital stay (LOS) associated with MRSA bloodstream infections (BSI) in European hospitals. Between July 2007 and June 2008, a multicenter, prospective, parallel matched-cohort study was carried out in 13 tertiary care hospitals in as many European countries. Cohort I consisted of patients with MRSA BSI and cohort II of patients with methicillin-susceptible S. aureus (MSSA) BSI. The patients in both cohorts were matched for LOS prior to the onset of BSI with patients free of the respective BSI. Cohort I consisted of 248 MRSA patients and 453 controls and cohort II of 618 MSSA patients and 1,170 controls. Compared to the controls, MRSA patients had higher 30-day mortality (adjusted odds ratio [aOR] = 4.4) and higher hospital mortality (adjusted hazard ratio [aHR] = 3.5). Their excess LOS was 9.2 days. MSSA patients also had higher 30-day (aOR = 2.4) and hospital (aHR = 3.1) mortality and an excess LOS of 8.6 days. When the outcomes from the two cohorts were compared, an effect attributable to methicillin resistance was found for 30-day mortality (OR = 1.8; P = 0.04), but not for hospital mortality (HR = 1.1; P = 0.63) or LOS (difference = 0.6 days; P = 0.96). Irrespective of methicillin susceptibility, S. aureus BSI has a significant impact on morbidity and mortality. In addition, MRSA BSI leads to a fatal outcome more frequently than MSSA BSI. Infection control efforts in hospitals should aim to contain infections caused by both resistant and susceptible S. aureus.

  16. Comparative study on the microbial adhesion to preveneered and stainless steel crowns

    Directory of Open Access Journals (Sweden)

    Waleed M Bin AlShaibah

    2012-01-01

    Full Text Available Context: The extensive plaque formation on dental restorations may contribute to secondary caries or periodontal inflammation. Therefore, it is important to know how different types of dental restorations may prevent or promote the accumulation of microorganisms. Aims: The aim of this in vivo study was to evaluate the adhesion of Streptococcus mutans to preveneered and stainless steel crowns (SSCs and to evaluate the effects of these restorations on the gingival health and oral hygiene. Materials and Methods: Twenty patients (age 3-5 years were selected from the outpatient clinic of the pedodontics department, Faculty of Oral and Dental Medicine, Cairo University. The selected patients had (dmf index for primary dentition ≤4, including lower right and left first primary molars. Each tooth was pulpotomy-treated and restored with either type of crowns (split-mouth technique. Then, ten swabs from the buccal mucosa, preveneered crown, and SSC surfaces were taken from each patient. Also, the gingival index (GI and oral hygiene index (OHI-S were measured at different times during the study. Mitis Salivarius Bacitracin agar (MSBA was used as a selective medium for S. mutans growth. MSBA plates were taken in candle jar and incubated aerobically in 37°C for 48 h. Finally, bacteria were counted and expressed in colony forming unit (CFU. Results: After 1, 2, and 4 weeks, mucosa and crown swabs of preveneered crown showed statistically significant higher mean CFU counts than SSC. Through the whole study period, the two restorations revealed a statistically significant decrease in mean CFU counts. Also, there was a statistically significant positive (direct correlation between OHI-S, GI, and S. mutans counts on both restorations. Conclusions: The adhesion of S. mutans to preveneered crowns was higher than to SSC. Full mouth rehabilitation led to significant decrease in S. mutans count in the short term. An increase in S. mutans counts is associated with

  17. Elliptic Fourier analysis of crown shapes in Quercus petraea trees

    Directory of Open Access Journals (Sweden)

    Ovidiu Hâruţa

    2011-06-01

    Full Text Available Shape is a fundamental morphological descriptor, significant in taxonomic research as well as in ecomorphology, one method of estimation being from digitally processed images. In the present study, were analysed shapes of Q. petraea crowns, pertaining to five different stem diameter classes, from three similar stands. Based on measurements on terrestrial digital vertical photos, crown size analysis was performed and correlations between crown and stem variables were tested. Linear regression equations between crown volumes and dbh, and crown volumes and stem volumes were derived, explaining more than half of data variability. Employment of elliptic Fourier analysis (EFA, a powerful analysis tool, permitted the extraction of the mean shape from crowns, characterized by high morphological variability. The extracted, most important, coefficients were used to reconstruct the average shape of the crowns, using Inverse Fourier Transform. A mean shape of the crown, corresponding to stand conditions in which competition is added as influential shaping factor, aside genetic program of the species, is described for each stem diameter class. Crown regions with highest shape variability, from the perspective of stage development of the trees, were determined. Accordingly, the main crown shape characteristics are: crown elongation, centroid position, asymmetry with regard to the main axis, lateral regions symmetrical and asymmetrical variations. 

  18. Elliptic Fourier analysis of crown shapes in Quercus petraea trees

    Directory of Open Access Journals (Sweden)

    Ovidiu Hâruţa

    2011-02-01

    Full Text Available Shape is a fundamental morphological descriptor, significant in taxonomic research as well as in ecomorphology, one method of estimation being from digitally processed images. In the present study, were analysed shapes of Q. petraea crowns, pertaining to five different stem diameter classes, from three similar stands. Based on measurements on terrestrial digital vertical photos, crown size analysis was performed and correlations between crown and stem variables were tested. Linear regression equations between crown volumes and dbh, and crown volumes and stem volumes were derived, explaining more than half of data variability. Employment of elliptic Fourier analysis (EFA, a powerful analysis tool, permitted the extraction of the mean shape from crowns, characterized by high morphological variability. The extracted, most important, coefficients were used to reconstruct the average shape of the crowns, using Inverse Fourier Transform. A mean shape of the crown, corresponding to stand conditions in which competition is added as influential shaping factor, aside genetic program of the species, is described for each stem diameter class. Crown regions with highest shape variability, from the perspective of stage developmentof the trees, were determined. Accordingly, the main crown shape characteristics are: crown elongation, mass center, asymmetry with regard to the main axis, lateral regions symmetrical and asymmetrical variations.

  19. Cerec anterior crowns: restorative options with monolithic ceramic materials.

    Science.gov (United States)

    Reich, Sven; Fiedlar, Kurt

    2013-01-01

    The aim of this article is to discuss the different types of monolithic ceramic crowns that can be placed on anterior teeth with existing shoulder preparations. Anterior crowns were indicated for the teeth 12 to 22 in the present case. The patient, a 65-year-old male, had received all-ceramic crowns 20 years earlier, which had started to develop cracks and palatal fractures over the last few years. The patient's teeth were prepared and four sets of crowns were fabricated using different monolithic ceramic materials: IPS e.max CAD, Cerec Blocs C In, VITABLOCS Real Life, and ENAMIC. Both shade characterization and crystallization firing were performed on the monolithic lithium disilicate glass ceramic crowns. The silicate ceramic crowns received glaze firing alone. The crowns made of hybrid ceramic (ENAMIC) were treated with a polymer sealant. PMID:24555406

  20. An analysis of clinical activity, admission rates, length of hospital stay, and economic impact after a temporary loss of 50% of the non-operative podiatrists from a tertiary specialist foot clinic in the United Kingdom

    Directory of Open Access Journals (Sweden)

    Catherine Gooday

    2013-09-01

    Full Text Available Introduction: Podiatrists form an integral part of the multidisciplinary foot team in the treatment of diabetic foot–related complications. A set of unforeseen circumstances within our specialist diabetes foot service in the United Kingdom caused a loss of 50% of our non-operative podiatry team for almost 7 months during 2010. Some of this time was filled by non-specialist community non-operative podiatrists. Methods: We assessed the economic impact of this loss by examining data for the 5 years prior to this 7-month interruption, and for the 2 years after ‘normal service’ was resumed. Results: Our data show that the loss of the non-operative podiatrists led to a significant rise in the numbers of admissions into hospital, and hospital length of stay also increased. At our institution a single bed day cost is £275. During the time that the numbers of specialist non-operative podiatry staff were depleted, and for up to 6 months after they returned to normal activities, the extra costs increased by just less than £90,000. The number of people admitted directly from specialist vascular and orthopaedic clinics is likely to have increased due to the lack of capacity to manage them in the diabetic foot clinic. Our data were unable to assess these individuals and did not look at the costs saved from avoiding surgery. Thus the actual costs incurred are likely to be higher. Conclusions: Our data suggest that specialist non-operative podiatrists involved in the treatment of the diabetic foot may prevent unwarranted hospital admission and increased hospitalisation rates by providing skilled assessment and care in the outpatient clinical settings.

  1. Adsorption of rare earths with crown ether adsorbents

    International Nuclear Information System (INIS)

    Crown ether - phosphotungstic acid (PW) and crown ether -phosphomolybdic acid (PMo) precipitates, and also the granular entrapped crown ether - PMo (or PW) in polyacrylamide, were prepared and applied as adsorbents for rare earth metal ions. Adsorbents containing 15-crown-5, such as 15-crown-5 - PMo, were better adsorbents than the other crown ether precipitates. The adsorption capacity of 15-crown-5 - PMo for Eu3+ was determined and corresponded to about 0.166 mmol of Eu3+ per gram of the absorbent. The effects of pH and metal ion concentration on adsorption were also investigated. Crown ether - PMo (or PW) precipitates underwent hydrolysis at pH >= 1, but the granular entrapped crown ether - PMo (or PW) - polyacrylamide adsorbents were not hydrolysed at pH >= 1. The adsorption of individual rare earth ions with 15-crown-5 - PMo - polyacrylamide showed that Tb3+, Nd3+, Eu3+ and Gd3+ were readily adsorbed, but adsorption was difficult for Ce4+, Sm3+ and Dy3+. (author)

  2. [Combined crown lengthening surgery with restorative therapy for inducing papilla growth: a case report].

    Science.gov (United States)

    Le, Di; Hu, Wen-jie; Zhang, Hao

    2013-04-18

    A young lady with unsatisfied restorations of upper anterior teeth and swollen gum wanted to improve aesthetics. Oral examination showed that 12-22 were provisional crowns with normal occlusion, poorly gingival contour and gummy smile. The gingiva was red, light swollen and bleeding on probing. X-ray showed the roots of 11, 21 were short and the alveolar bone absorbed. After the periodontal initial treatment, an ideal location of gingival margin was determined. Then, an esthetic periodontal surgery was performed to recover the biology width and the gingival margin was fitted with the anterior teeth. The temporary restorations were made twice to guide the gingiva growth by changing the shape of the restorations and moving up the contact points of the restorations. The ceramic crowns were completed 3 months after the operation. The gummy smile disappeared and the gingival margin was filled well with the upper anterior ceramic crowns. The 14-month follow-up presented a satisfied effect. Crown lengthening surgery combined restorative therapy could lead papilla to grow well. This process is beneficial for the future treatment plan and clinical esthetic evaluation.

  3. Winter habitat selection of red-crowned crane (Grus japonensis)

    Institute of Scientific and Technical Information of China (English)

    张洪海; 杨月伟

    2000-01-01

    This paper studied the winter habitat selection of red-crowned cranes (Grus japonensis) in Yancheng National Natural Reserve, Jiangsu Province. There were six types of habitat used by red-crowned cranes, i.e. salt-works, aquiculture ponds, reed lands, grassy tidal lands, salting wormwood lands and wheat fields. The wheat field was a new type of habitat used by red-crowned cranes. More than 70 percent of red-crowned cranes chose grassy tidal lands, salting wormwood lands, and reed lands as their most important habitats. In recent years, the distribution of red-crowned cranes moved southward gradually. Red-crowned cranes prefer artificial or semi-artificial wetlands rather than original wetlands, successive distribution was broken into fragments.

  4. Microwave-assisted fast and efficient synthesis of some crown ethers

    Institute of Scientific and Technical Information of China (English)

    Ahmad Ziafati; Hossein Eshghi; Omolbanin Sabzevari

    2009-01-01

    13-Crown-4, 16-crown-5, dibenzo-12-crown-4 and dibenzo-14-crown-4 were synthesized by a one-pot microwave-assisted procedure in good yields. Irradiation of diols and dichlorides in the presence of sodium hydroxide in DMSO gave title crown ethers presumably within a template effect.

  5. Can hyaluronan injections augment deficient papillae at implant-supported crowns in the anterior maxilla?

    DEFF Research Database (Denmark)

    Bertl, Kristina; Gotfredsen, Klaus; Jensen, Simon S;

    2016-01-01

    OBJECTIVES: The present randomized controlled trial aimed to assess the effect of hyaluronan (HY) injections to augment deficient interproximal papillae at implant-supported crowns in the anterior maxilla. METHODS: Twenty-two patients with a deficient papilla in the anterior maxilla next to an im......OBJECTIVES: The present randomized controlled trial aimed to assess the effect of hyaluronan (HY) injections to augment deficient interproximal papillae at implant-supported crowns in the anterior maxilla. METHODS: Twenty-two patients with a deficient papilla in the anterior maxilla next...... index score (MPIS), and standard clinical periodontal parameters. Pain level after injection was recorded on a visual analogue scale (VAS). The deficient area was evaluated on clinical photographs, and the esthetic appearance was recorded on a VAS. Differences in mucosal volume were assessed after 3...

  6. Zirconia crowns - the new standard for single-visit dentistry?

    Science.gov (United States)

    Wiedhahn, Klaus; Fritzsche, Günter; Wiedhahn, Claudine; Schenk, Olaf

    2016-01-01

    Zirconia crowns combine the advantages of metal restorations, such as minimally invasive tooth preparation and ease of cementation, with those of full ceramic crowns, such as low thermal conductivity and tooth color. With the introduction of a high-speed sintering procedure, it is possible to produce and cement zirconia crowns and small monolithic bridges in a Cerec Single Visit procedure. This new procedure is compared to established chairside methods.

  7. Two Mathematical Models for Generation of Crowned Tooth Surface

    OpenAIRE

    Laszlo Kelemen; Jozsef Szente

    2014-01-01

    Gear couplings are mechanical components to connect shaft ends and eliminate the misalignments. The most important element of the gear coupling is the hub which is an external gear having crowned teeth. The crowned teeth on the hub are typically produced by hobbing. The resulting tooth surface depends on several parameters. It is influenced by the size of the hob and the feed. In this paper two mathematical models of the crowned tooth surface are introduced for the generation of the idealized...

  8. Elliptic Fourier analysis of crown shapes in Quercus petraea trees

    OpenAIRE

    Ovidiu Hâruţa

    2011-01-01

    Shape is a fundamental morphological descriptor, significant in taxonomic research as well as in ecomorphology, one method of estimation being from digitally processed images. In the present study, were analysed shapes of Q. petraea crowns, pertaining to five different stem diameter classes, from three similar stands. Based on measurements on terrestrial digital vertical photos, crown size analysis was performed and correlations between crown and stem variables were tested. Linear regression ...

  9. The reparation of residual roots and residual crowns and masticatory function%残根和残冠的修复与咀嚼功能

    Institute of Scientific and Technical Information of China (English)

    张俊杰

    2002-01-01

    @@ 1 The evidences of the reparation of residual roots and residual crowns and the clinical significances Lots of patients have severe physical and mental pain and life quality decrease resulted from the extraction of residual roots and residual crowns. With science development, new material application and designing method promotion, several artificial teeth have replaced the extraction of teeth. In some degree, the method have relieved the pain of no teeth.

  10. [Estimating nonstructural carbon content of tree crown considering its spatial variability: A case study on Juglans mandshurica and Ulmus japonica].

    Science.gov (United States)

    Cheng, Fang-yan; Wang, Chuan-kuan

    2015-08-01

    Using Juglans mandshurica and Ulmus japonica as test materials, we examined the variability in nonstructural carbohydrates (NSC) concentrations in the branches with different basal diameters with a branch analysis method and explored potential errors in estimating the crown-scale NSC content introduced from various sampling protocols. The results showed that organs significantly influenced the crown NSC concentrations for both species. The mean concentrations of the sum of soluble sugars and starch (TNC) of the leaves, new twigs, old branches, and dead branches were 17.6%, 12.6%, 5.7% and 2.9%, respectively. Most of the NSC concentrations in leaves and new twigs varied insignificantly with basal diameter, age, length and height of the branch. However, the NSC concentration in old branches increased significantly with decreasing the basal diameter, age and length of the branch, and with increasing the relative height of the branch. Among the branch traits, basal diameter was the best predictor for the NSC concentration of the old branch (the R2 between 0.87 and 0.95). The mean TNC contents of leaves, new branches, and old branches for the two species accounted for 28%, 2% and 70% of the crown TNC content, respectively. Considering the effect of the spatial variability in the estimation of NSC content, we recommend the sampling protocol that applies the NSC concentration of new twigs and old branches with a diameter of 3 cm to up-scale the crown NSC content as a simple and practical method.

  11. Aesthetic treatment on anterior teeth crown fracture caused by dental trauma

    Directory of Open Access Journals (Sweden)

    Nanik Zubaidah

    2012-12-01

    Full Text Available Background: Complicated crown fracture is a tooth fracture that involve enamel, dentine and pulp. The incidence of complicated crown fracture ranges from 2% to 13% of all dental injuries and the most commonly involved teeth are the maxillary central incisors. Various treatment modalities are available depending on the clinical, physiological and radiographic examination of the involved teeth. Purpose: The aim of this case report is to present the management of crown fractures with pulpal exposure caused by traumatic injury, through endorestoration approach to reconstruct the shape and function of the teeth. Case: A 17 years old male with complicated crown fractures of anterior teeth #11 #21 and #22. The patient wish for aesthetic dental treatment in both of its form and function. Case management: Crown fractures of anterior teeth with exposed pulp caused by traumatic injury were reconstructed by endorestoration approach. The endodontic treatment with post and core insertion in the root canal which will increase its retention and porcelain fused to metal crown which will aesthetically recover its original form and function. After restoration the patient feel very glad and confident with the result. Conclusion: Endorestoration treatment on anterior teeth with complicated crown fractures and exposed pulp is able to recover the normal form, function and dental aesthetic in accordance with stomatognatic system and self confidence.Latar belakang: Fraktur mahkota kompleks (complicated adalah fraktur pada mahkota gigi yang melibatkan enamel, dentin dan pulpa. Kejadian dari fraktur mahkota kompleks bervariasi antara 2-13% dari semua trauma gigi dan sebagian besar gigi yang terkena adalah gigi insisif pertama rahang atas. Berbagai macam cara perawatan yang dilakukan tergantung pada hasil pemeriksaan klinis, psikologis dan radiografis dari gigi yang terkena. Tujuan: Laporan kasus ini menjelaskan penatalaksanaan fraktur mahkota gigi dengan pulpa terbuka

  12. Basal ganglia - thalamus and the crowning enigma

    Directory of Open Access Journals (Sweden)

    Marianela eGarcia-Munoz

    2015-11-01

    Full Text Available When Hubel (1982 referred to layer 1 of primary visual cortex as …a ‘crowning mystery’ to keep area-17 physiologists busy for years to come... he could have been talking about any cortical area. In the 80’s and 90’s there were no methods to examine this neuropile on the surface of the cortex: a tangled web of axons and dendrites from a variety of different places with unknown specificities and doubtful connections to the cortical output neurons some hundreds of microns below. Recently, three changes have made the crowning enigma less of an impossible mission: the clear presence of neurons in layer 1 (L1, the active conduction of voltage along apical dendrites and optogenetic methods that might allow us to look at one source of input at a time. For all of those reasons alone, it seems it is time to take seriously the function of L1. The functional properties of this layer will need to wait for more experiments but already L1 cells are GAD67 positive, i.e., inhibitory! They could reverse the sign of the thalamic glutamate (GLU input for the entire cortex. It is at least possible that in the near future normal activity of individual sources of L1 could be detected using genetic tools. We are at the outset of important times in the exploration of thalamic functions and perhaps the solution to the crowning enigma is within sight. Our review looks forward to that solution from the solid basis of the anatomy of the basal ganglia output to motor thalamus. We will focus on L1, its afferents, intrinsic neurons and its influence on responses of pyramidal neurons in layers 2/3 and 5. Since L1 is present in the whole cortex we will provide a general overview considering evidence mainly from the somatosensory cortex before focusing on motor cortex.

  13. The influence of tooth preparation and crown manipulation on the mechanical retention of stainless steel crowns.

    Science.gov (United States)

    Rector, J A; Mitchell, R J; Spedding, R H

    1985-01-01

    The belief that close adaptation of the metal margins to tooth surfaces in the undercut areas is the most important retentive feature, was borne out in this study. The type of preparation did not affect the retention of stainless steel crowns.

  14. A Rare Case of Crowned Dens Syndrome Mimicking Aseptic Meningitis

    Directory of Open Access Journals (Sweden)

    Teruyuki Takahashi

    2013-03-01

    Full Text Available Background: Crowned dens syndrome (CDS, related to microcrystalline deposition in the periodontoid process, is the main cause of acute or chronic cervical pain. Microcrystal-line deposition most often consists of calcium pyrophosphate dehydrate crystals and/or hydroxyapatite crystals. Case Presentation: This report describes the case of an 89-year-old woman who presented with sudden onset, high fever, severe occipital headache, and neck stiffness. A laboratory examination revealed a markedly elevated white blood cell count (11,100/µl and C-reactive protein level (23.8 mg/dl. These clinical findings suggested severe infection such as meningitis with sepsis. However, the results of blood culture, serum endotoxin, and procalcitonin were all negative, and cerebrospinal fluid studies revealed only a slight abnormality. The patient was first diagnosed with meningitis and treated with antiviral and antibiotic agents as well as non-steroidal anti-inflammatory drugs, but they only had limited effects. A cervical plain computed tomography (CT scan and its three-dimensional (3D reconstruction detected a remarkable crown-like calcification surrounding the odontoid process. On the basis of the CT findings, the patient was diagnosed as a severe case of CDS and was immediately treated with corticosteroids. The patient's condition drastically improved within a week after one course of corticosteroid therapy. Conclusion: Some atypical symptoms of CDS are misleading and may be misdiagnosed as meningitis, as happened in our case. A CT scan, especially a 3D-CT scan, is necessary and useful for a definitive diagnosis of CDS. CDS should be considered as a differential diagnosis of a possible etiology for fever, headache, and cervical pain of unknown origin.

  15. Guided esthetic crown lengthening: case reports.

    Science.gov (United States)

    Borges, Ivan; Ribas, Tania Rocha Cabral; Duarte, Poliana Mendes

    2009-01-01

    It is well-recognized that excessive gingival display can have a negative impact on a patient's smile. Excessive gingival display due to gingival enlargement or altered passive eruption (dentogingival cause) can be corrected effectively through periodontal surgeries. This article describes two successful esthetic crown-lengthening surgeries that were guided by an acetate template to better predict the outcomes of the surgical procedures in relation to the symmetry and harmony of the gingival contour. This article also highlights the importance of utilizing an interdisciplinary approach to obtain an optimum esthetic result for restorative treatments in the anterior maxilla.

  16. 人工全髋关节置换术后双下肢长度的变化%Clinical changes of leg length after total hip arthroplasty

    Institute of Scientific and Technical Information of China (English)

    王义生; 陈宾; 李军伟; 张弛

    2012-01-01

    目的:观察人工全髋关节置换术后双下肢长度的变化.方法:2009年1月至2011年6月接受单侧和双侧人工全髋关节置换术的患者117例(152髋),术前下肢等长35例,不等长82例.所有病例均使用生物型假体关节行全髋关节置换.测量术后1周内的下肢长度,计算术后双下肢长度之差,视双下肢长度之差≤10 mm者为等长.结果:117例患者中,术后下肢等长116例(99.2%),双下肢长度相差11 mm者1例(0.9%);116例中术后双下肢完全等长108例(92.3%),相差<6 mm者5例,相差6~10 mm者3例.结论:充分掌握各种术中测量下肢长度的方法,综合运用于平衡下肢长度,术中多次比对可降低术后下肢不等长的发生率.%Aim:To investigate the changes of leg length after total hip arthroplasty. Methods: A total of 117 patients ( 152 hip joints ) from January 2009 to June 2011 were followed up routinely. Before the operation there were 35 cases whose lower limbs were defined as the equal length, and 82 cases, unequal length. The artificial joints of all the cases were cement-less prosthesis. The leg length after the operation( within a week ) were measured. Results:In all the 117 cases, there were 116 cases whose lower limbs were equal long,and 1 case whose leg length discrepancy( LLD ) was 11 mm;among the 116cases,108 cases( 92. 3% ) whose LLD was 0 mm,5 cases whose LLD was less than 6 mm,and 3 cases whose LLD was between 6 ~ 10 mm. Conclusion: The various intraoperative methods of measuring leg length can significantly reduce the incidence of postoperative LLD.

  17. Simplified Fabrication of an Esthetic Implant-Supported Crown With a Novel CAD/CAM Glass Ceramic.

    Science.gov (United States)

    Conejo, Julián; Blatz, Markus B

    2016-06-01

    Implant therapy and CAD/CAM technologies are advancing quickly, providing predictable esthetic and functional treatment options. A recent development involves the use of zirconia-reinforced lithium-silicate ceramic for fabrication of implant-supported restorations. Suitable for monolithic crowns, the material provides the optical advantages of a silicate ceramic with improved physical strength. Several prerequisites, however, are necessary to fabricate screw-retained monolithic restorations in the anterior maxilla. This case report demonstrates the clinical steps to fabricate a monolithic ceramic CAD/CAM crown on an immediately placed dental implant in the esthetic zone. PMID:27517477

  18. Functional aspects of treatment with implant-supported single crowns: a quality control study in subjects with tooth agenesis

    DEFF Research Database (Denmark)

    Goshima, Kenichi; Lexner, Michala O; Thomsen, Carsten Eckhart;

    2010-01-01

    after implant placement shortly before crown cementation, and again 1 month after cementation. It consisted of questionnaires [including Oral Health Impact Profile (OHIP-49)] and functional examination with plastic strips, the Dental Prescale Film and the Occluzer system, Xylitol color-changeable gum......BACKGROUND: No comprehensive patient-centered and clinical evaluations of the functional effect of treatment with implant-supported single crowns (ISSC) have been reported previously. OBJECTIVE: To investigate whether and how treatment with ISSC affects masticatory function and Oral Health...

  19. Multidisciplinary approach for the treatment of a complicated crown-root fracture in a young patient: a case report.

    Science.gov (United States)

    de Castro, José Carlos Monteiro; Poi, Wilson Roberto; Pedrini, Denise; Tiveron, Adelisa Rodolfo Ferreira; Brandini, Daniela Atili; de Castro, Mara Antônio Monteiro

    2011-10-01

    Crown-root fractures in permanent teeth cause esthetic and functional problems. This paper reports the case of a complicated crown-root fracture in the maxillary right central incisor of a young patient who was treated with a multidisciplinary approach in two phases. A modified Widman flap, root canal therapy, glass fiber post cementation, and adhesive tooth fragment reattachment were performed shortly after an accident. Satisfactory esthetic and functional outcomes were obtained. However, the patient did not attend follow-up visits and returned after 7 years. During this second phase, the clinical and radiographic examination showed stability and adaptation of the fragment and good periodontal health conditions, but crown darkening and a radiolucent image associated with the root apex of the fractured tooth were also observed. The periapical lesion was surgically removed by apicoectomy, and the esthetics were recovered with a direct composite resin veneer on the traumatized tooth. PMID:21909497

  20. Clinical Impact of Antimicrobial Resistance in European Hospitals : Excess Mortality and Length of Hospital Stay Related to Methicillin-Resistant Staphylococcus aureus Bloodstream Infections

    NARCIS (Netherlands)

    de Kraker, Marlieke E. A.; Wolkewitz, Martin; Davey, Peter G.; Grundmann, Hajo

    2011-01-01

    Antimicrobial resistance is threatening the successful management of nosocomial infections worldwide. Despite the therapeutic limitations imposed by methicillin-resistant Staphylococcus aureus (MRSA), its clinical impact is still debated. The objective of this study was to estimate the excess mortal

  1. Metal ion complexation by ionizable crown ethers: Progress report, January 1, 1985-December 31, 1987

    Energy Technology Data Exchange (ETDEWEB)

    Bartsch, R.A.

    1987-06-01

    A variety of lipophilic crown ethers with pendant ionizable groups has been prepared. Several lipophilic acyclic polyethers bearing either one or two ionizable groups have also been synthesized. Complexation of alkali metal and alkaline earth cations by such novel ligands has been probed using NMR and solvent extraction. Effects of ring size, side arm length, ionizable group identity and other structural variations, as well as the effect of the solvent, the competitive alkali metal cation solvent extraction has been assessed. Investigations of heavy metal and transition metal cation complexation by ionizable crown ethers have been conducted. The influence of structural variations within acyclic polyether carboxylic acids and dicarboxylic acids on the alkali metal and alkaline earth cation solvent extraction has also been probed. New ligands have been developed which exhibit high selectivities for Cs/sup +/ and Ra/sup 2 +/ in solvent extraction processes. The ability of ionizable crown ethers to function as selective metal cation carriers in liquid membrane transport processes has been examined in both bulk liquid membrane and polymer-supported liquid membrane transport systems.

  2. Reduction of HCCI combustion noise through piston crown design

    DEFF Research Database (Denmark)

    Pedersen, Troels Dyhr; Schramm, Jesper

    2010-01-01

    Seven shapes of piston crowns have been evaluated for their ability to reduce HCCI knock and transmission of combustion noise to the engine. The performance of each piston crown was evaluated with measurements of cylinder pressure, engine vibration and acoustic sound pressure measured one meter a...

  3. Isotope effects of hafnium in solvent extraction using crown ethers

    Energy Technology Data Exchange (ETDEWEB)

    Fujii, Toshiyuki; Moriyama, Hirotake [Research Reactor Institute, Kyoto University, Osaka (Japan); Hirata, Takafumi [Laboratory for Planetary Sciences, Tokyo Institute of Technology, Tokyo (Japan); Nishizawa, Kazushige [Department of Nuclear Engineering, Graduate School of Engineering, Osaka University, Osaka (Japan)

    2001-06-01

    Hafnium isotopes were fractionated in a liquid-liquid extraction system by using seven types of crown ethers, tributyl phosphate, or {omicron}-diethoxybenzene. The largest isotope effect was observed in the isotope pair of {sup 177}Hf-{sup 179}Hf with dibenzo-24-crown-8; the isotope enrichment factor was observed to be 0.0129{+-}0.0032. (author)

  4. Estimation of genome length

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The genome length is a fundamental feature of a species. This note outlined the general concept and estimation method of the physical and genetic length. Some formulae for estimating the genetic length were derived in detail. As examples, the genome genetic length of Pinus pinaster Ait. and the genetic length of chromosome Ⅵ of Oryza sativa L. were estimated from partial linkage data.

  5. An interdisciplinary approach to treat crown-root-fractured tooth

    Directory of Open Access Journals (Sweden)

    Ying Chun Sun

    2013-01-01

    Full Text Available Restoration of a crown-root subgingival fractured tooth, especially at anterior aesthetic zones is still a great challenge for restorative dentists. Crown lengthening procedure alone has the disadvantage of high gingival curve of the final restoration, which was not discontinuous to adjacent teeth and thus compromise cosmetic outcomes. The objective of this report is to display a new interdisciplinary approach which combining endodontic root canal treatment, orthodontic extrusion, periodontal crown lengthening surgery and prosthodontic post-core-crown restoration procedures to restore a crown-root subgingival fractured maxillary central incisor and achieved a satisfied cosmetic result. Computer-based spectrophotometer was also used to accurately select colour without objective interference to achieve ideal cosmetic effects.

  6. An interdisciplinary approach to treat crown-root-fractured tooth.

    Science.gov (United States)

    Sun, Ying Chun; Li, Ying; Tong, Jian; Gao, Ping

    2013-07-01

    Restoration of a crown-root subgingival fractured tooth, especially at anterior aesthetic zones is still a great challenge for restorative dentists. Crown lengthening procedure alone has the disadvantage of high gingival curve of the final restoration, which was not discontinuous to adjacent teeth and thus compromise cosmetic outcomes. The objective of this report is to display a new interdisciplinary approach which combining endodontic root canal treatment, orthodontic extrusion, periodontal crown lengthening surgery and prosthodontic post-core-crown restoration procedures to restore a crown-root subgingival fractured maxillary central incisor and achieved a satisfied cosmetic result. Computer-based spectrophotometer was also used to accurately select colour without objective interference to achieve ideal cosmetic effects.

  7. Calorimetric study of binding of some disaccharides with crown ethers

    Energy Technology Data Exchange (ETDEWEB)

    Davydova, Olga I.; Lebedeva, Nataliya Sh.; Parfenyuk, Elena V

    2004-11-01

    Isothermal titration calorimetry has been applied to the determination of the thermodynamic parameters of binding of {beta}-lactose, {alpha},{alpha}-trehalose and sucrose with 15-crown-5 and 18-crown-6 in water at 298.15 K. The formation of 1:1 molecular associates has been found for the systems studied except 18-crown-6 and {beta}-lactose. The associates are preferentially or completely entropy stabilized. The most stable associate is formed between {alpha},{alpha}-trehalose and 18-crown-6. The obtained values of thermodynamic parameters of binding are discussed from the point of view of solute-solvent interactions as well as conformational and structural peculiarities of the disaccharides (DS) and crown ethers (CE)

  8. Effect of Initial Crown on Shape of Hot Rolled Strip

    Institute of Scientific and Technical Information of China (English)

    HU Yu; GONG Dian-yao; JIANG Zheng-yi; XU Jian-zhong; ZHANG Dian-hua; LIU Xiang-hua

    2009-01-01

    Based on the influence coefficient method, the effect of entry strip crown on the shape of hot rolled strip was analyzed using the software of roll elastic deformation simulation. According to the practical condition of a domestic hot roiled strip plant, the unit strip crown change from the first stand to the last stand was calculated when the entry crown of hot strip varies. The calculated result shows that the entry strip crown does not significantly affect the target strip crown at the exit of the last finishing stand in respect to a fixed strip shape control reference (such as bending force). The calculation was analyzed, and the research is helpful in modeling strip shape setup and shape control.

  9. 前牙龈下冠根折正畸牵引联合修复的治疗分析%Treatment analysis of anterior subgingival crown-root fracture with traction of orthodontic treatment and repairing

    Institute of Scientific and Technical Information of China (English)

    郭爱军; 李向荣; 孔锐

    2011-01-01

    目的:观察冠根折至龈下的前牙正畸牵引联合修复治疗方法的临床疗效.方法:将患牙进行完善根管治疗后在根管内粘固长度小于根长1/2的0.5mm的不锈钢丝,在两侧健康牙面上粘托槽,采用不锈钢方丝作主弓丝并加牵引钩,链状橡皮圈牵引.3个月后牙根牵引到位,6个月后行桩冠修复.结果:2005~2009年共治疗36颗患牙,其中1颗失败,其余治疗效果满意.结论:对于前牙冠根折至龈下的病例,采用正畸牵引后桩冠修复的方法可以增加保留机会,获得较为满意的功能和美学效果.%Objective To investigate the subgingival crown-root fracture to the anterior joint repair orthodontic treatment of clinical efficacy. Methods To perfect teeth after root canal therapy root canal cements in the length of the root length is less than 1/2 0.5mm stainless steel wire,the surface of healthy teeth on both sides stick brackets, stainless steel arch wire square wire decide plus towing hooks,chain rubber band traction. After the root traction in place in March,six months underwent post crown. Results 36 teeth were treated in 2005 to 2009,of which one failed, the other therapeutic effect. Conclusion For the first to subgingival crown-root fracture cases, the use of orthodontic traction after the crown after ways to increase the retention opportunities, access to satisfactory functional and aesthetic results.

  10. Using 15-crown-5, 18-crown-6 and dicyclohexano-18-crown-6 for Am, Ce, Eu and Cm extraction from acid solutions

    International Nuclear Information System (INIS)

    The extraction from nitric acid of Am, Eu, Ce, Cm(III) tracers by 15-crown-5 (15C5), 18-crown-6 (18C6), dicyclohexano-18-crown-6 (DCH18C6) as well as mixtures of crown ethers and chlorinated cobalt dicarbollide (ChCoD) in nitrobenzene solutions has been investigated. It was revealed that 18C6 is selective for Ce, Am and Cm compared with Eu. The addition of 18C6 to a solution of ChCoD allows Am and Cm to be separated from lanthanides by using this extractant more efficiently. The separation factors of Ce, Am, Cm and Eu are increased as a function of the ionic strength of the aqueous phase for extraction by mixtures of 18C6 and ChCoD and of DCH18C6 and ChCoD

  11. Scattered radiation from dental metallic crowns in head and neck radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Shimozato, T; Tabushi, K; Obata, Y; Komori, M [Department of Radiological Technology, Nagoya University School of Health Sciences, 1-1-20 Daikohminami, Higashi-ku, Nagoya, Aichi 461-8673 (Japan); Igarashi, Y [Department of Radiological Technology, Nagoya University Graduate School of Medicine, 1-1-20 Daikohminami, Higashi-ku, Nagoya, Aichi 461-8673 (Japan); Itoh, Y; Naganawa, S [Department of Radiology, Nagoya University Graduate School of Medicine, 65 Tsuruma-chou, Shouwa-ku, Nagoya, Aichi 466-8560 (Japan); Yamamoto, N; Ueda, M [Department of Oral and Maxillofacial Surgery, Nagoya University Graduate School of Medicine, 65 Tsuruma-chou, Shouwa-ku, Nagoya, Aichi 466-8560 (Japan); Okudaira, K, E-mail: shimo-p@umin.ac.jp [Department of Radiology, Nagoya University Hospital, 65 Tsuruma-chou, Shouwa-ku, Nagoya, Aichi 466-8560 (Japan)

    2011-09-07

    We aimed to estimate the scattered radiation from dental metallic crowns during head and neck radiotherapy by irradiating a jaw phantom with external photon beams. The phantom was composed of a dental metallic plate and hydroxyapatite embedded in polymethyl methacrylate. We used radiochromic film measurement and Monte Carlo simulation to calculate the radiation dose and dose distribution inside the phantom. To estimate dose variations in scattered radiation under different clinical situations, we altered the incident energy, field size, plate thickness, plate depth and plate material. The simulation results indicated that the dose at the incident side of the metallic dental plate was approximately 140% of that without the plate. The differences between dose distributions calculated with the radiation treatment-planning system (TPS) algorithms and the data simulation, except around the dental metallic plate, were 3% for a 4 MV photon beam. Therefore, we should carefully consider the dose distribution around dental metallic crowns determined by a TPS.

  12. Establishment of crown-root domain borders in mouse incisor.

    Science.gov (United States)

    Juuri, Emma; Saito, Kan; Lefebvre, Sylvie; Michon, Frederic

    2013-10-01

    Teeth are composed of two domains, the enamel-covered crown and the enamel-free root. The understanding of the initiation and regulation of crown and root domain formation is important for the development of bioengineered teeth. In most teeth the crown develops before the root, and erupts to the oral cavity whereas the root anchors the tooth to the jawbone. However, in the continuously growing mouse incisor the crown and root domains form simultaneously, the crown domain forming the labial and the root domain the lingual part of the tooth. While the crown-root border on the incisor distal side supports the distal enamel extent, reflecting an evolutionary diet adaptation, on the incisor mesial side the root-like surface is necessary for the attachment of the interdental ligament between the two incisors. Therefore, the mouse incisor exhibits a functional distal-mesial asymmetry. Here, we used the mouse incisor as a model to understand the mechanisms involved in the crown-root border formation. We analyzed the cellular origins and gene expression patterns leading to the development of the mesial and distal crown-root borders. We discovered that Barx2, En1, Wnt11, and Runx3 were exclusively expressed on the mesial crown-root border. In addition, the distal border of the crown-root domain might be established by cells from a different origin and by an early Follistatin expression, factor known to be involved in the root domain formation. The use of different mechanisms to establish domain borders gives indications of the incisor functional asymmetry.

  13. The sensitivity of length of pregnancy using clinical estimate of gestation versus last menstrual period: an example with particulate matter and preterm birth

    Science.gov (United States)

    Estimating gestational age is usually based on last menstrual period date (LMP) or clinical estimation (CGA); both approaches introduce error and potential bias. Differences in the two methods of gestational age assignment may lead to misclassification and differences in risk est...

  14. Synthesis, characterization and antibacterial activity of new complexes of some lanthanide ions with 15-crown-5 and 18-crown-6

    Directory of Open Access Journals (Sweden)

    Hussein Al-Amery

    2016-05-01

    Full Text Available Complexes of some lanthanide picrates (Ln3+ = Pr3+, Nd3+ and Dy3+ with 15-crown-5 and 18-crown-6 were synthesized and characterized by elemental analysis, ICP-AES, FTIR, 1H-NMR, 13C-NMR and UV-Visible spectrophotometric methods, thermal analysis (TGA & DTG, magnetic susceptibility , molar conductance and melting points. Also an in-vitro study on pathogenic gram positive (Staphylococcus aureus and pathogenic gram negative bacteria (Escherichia coli, Salmonella and pseudomonas aeruginosa was performed and the results were compared to those of a broad spectrum antibiotic (Chloramphinicol. The complexes of 15-crown-5 have the general formula [Ln(15C52(Pic]Pic2.nH2O where (Ln3+ = Nd3+ and Dy3+, (Pic = Picrate anion and (n = 2 or 4 except for Pr3+ complex which has the formula [Pr(15C5]Pic3.H2O , the 18-crown-6 complexes have the general formula [Ln(18C6]Pic3 where (Ln3+ = Pr3+ and Nd3+ except for Dy3+ complex which has the formula [Dy(18C6(Pic]Pic2.3H2O. In 15-crown-5 complexes both Nd3+ and Dy3+ were coordinated with two 15-crown-5 ligands and one picrate anion through its phenolic oxygen and the oxygen of it’s ortho nitro group, except for Pr3+ which was coordinated with only one 15-crown-5 ligand leaving three picrate anions as counter ions. In 18-crown-6 complexes both Pr3+ and Nd3+ were coordinated with one 18-crown-6 ligand leaving all the three picrate anions as counter ions outside the coordination sphere, except for the Dy3+ complex which was coordinated with one 18-crown-6 ligand and one picrate anion.

  15. Triaquachlorido(18-crown-6barium chloride

    Directory of Open Access Journals (Sweden)

    Min-Min Zhao

    2012-03-01

    Full Text Available In the title compound, [BaCl(C12H24O6(H2O3]Cl, the BaII atom, the coordinating and free Cl− anions, one coordinating water molecule and two O atoms of an 18-crown-6 molecule lie on a mirror plane. The environment of the ten-coordinate Ba2+ ion is defined by one Cl atom, three water molecules and six O atoms from the macrocyclic ether. The macrocycle adopts a conformation with an approximate D3d symmetry. In the crystal, O—H...Cl hydrogen bonds link the complex cations and Cl− anions into a two-dimensional network parallel to (010. An intramolecular O—H...Cl hydrogen bond is also present.

  16. A biometric approach to predictable treatment of clinical crown discrepancies.

    Science.gov (United States)

    Chu, Stephen J

    2007-08-01

    Dental professionals have long been guided by mathematical principles when interpreting aesthetic and tooth proportions for their patients. While many acknowledge that such principles are merely launch points for a smile design or reconstructive procedure, their existence appears to indicate practitioners' desire for predictable, objective, and reproducible means of achieving success in aesthetic dentistry. This article introduces innovative aesthetic measurement gauges as a means of objectively quantifying tooth size discrepancies and enabling the clinician to perform aesthetic restorative dentistry with success and predictability.

  17. Silica crown refractory corrosion in glass melting furnaces

    Directory of Open Access Journals (Sweden)

    Balandis A.

    2011-01-01

    Full Text Available The critical parameters of silica refractories, such as compressive strength, bulk, density, quantity of silica, microstructure and porosity were evaluated of unused and used bricks to line the crowns of glass furnaces, when the rate of corrosion of crowns were about 2 times greater. The change of these parameters, the chemical composition and formation of the microcracks in the used silica refractories material were studied. It was established that the short time at service of container glass furnace crown can be related to low quality of silica brick: high quantity of CaO and impurities, low quantity of silica, low quantity of silica, transferred to tridymite and cristobalite and formation of 5-10 μm and more than 100 μm cracks in the crown material. The main reason of corrosion high quality silica bricks used to line the crown of electrovacuum glass furnace is the multiple cyclic change of crown temperature at 1405 - 1430°C range in the initial zone of crown and at 1575 - 1605°C range in the zone of highest temperatures.

  18. Review of Alberta Crown Crude Oil Marketing Program

    International Nuclear Information System (INIS)

    This report contains an independent evaluation of the operations of the private marketing agents that are currently marketing the Alberta Crown's share of royalty crude oil. The evaluation includes a review of pricing performance, working relationship, current issues and the overall performance of the marketing arrangements during the fiscal years of 1997 and 1998. Overall, the outsourcing of sales of Crown production to agents is judged to be successful. For example, it has been noted that agents are becoming more aggressive in maintaining and increasing their margins. On the other hand, the increased level of aggressiveness in marketing, while tending to maximize Crown revenues, is also creating a potential conflict on how margins should be shared between the Crown and its agents. Also, there has been evidence of some management issues between the agents and the Crown concerning the extent to which the Crown should share in any increased value which the agent generates by increased third party marketing activities. These differences need to be addressed in order to maintain the strong performance of the marketing program. The consultants also recommend additional guidelines on risk management issues that more clearly define the Crown's risk tolerance. 2 tabs., 4 figs

  19. Investigation of the time-dependent wear behavior of veneering ceramic in porcelain fused to metal crowns during chewing simulations.

    Science.gov (United States)

    Guo, Jiawen; Tian, Beimin; Wei, Ran; Wang, Weiguo; Zhang, Hongyun; Wu, Xiaohong; He, Lin; Zhang, Shaofeng

    2014-12-01

    The excessive abrasion of occlusal surfaces in ceramic crowns limits the service life of restorations and their clinical results. However, little is known about the time-dependent wear behavior of ceramic restorations during the chewing process. The aim of this in vitro study was to investigate the dynamic evolution of the wear behavior of veneering porcelain in PFM crowns as wear progressed, as tested in a chewing simulator. Twenty anatomical metal-ceramic crowns were prepared using Ceramco III as the veneering porcelain. Stainless steel balls served as antagonists. The specimens were dynamically loaded in a chewing simulator with 350N up to 2.4×10(6) loading cycles, with additional thermal cycling between 5 and 55°C. During the testing, several checkpoints were applied to measure the substance loss of the crowns' occlusal surfaces and to evaluate the microstructure of the worn areas. After 2.4×10(6) cycles, the entire wear process of the veneering porcelain in the PFM crowns revealed three wear stages (running-in, steady and severe wear stages). The occlusal surfaces showed traces of intensive wear on the worn areas during the running-in wear stage, and they exhibited the propagation of cracks in the subsurface during steady wear stage. When the severe wear stage was reached, the cracks penetrated the ceramic layer, causing the separation of porcelain pieces. It also exhibited a good correlation among the microstructure, the wear loss and the wear rate of worn ceramic restorations. The results suggest that under the conditions of simulated masticatory movement, the wear performance of the veneering porcelain in PFM crowns indicates the apparent similarity of the tribological characteristics of the traditional mechanical system. Additionally, the evaluation of the wear behavior of ceramic restorations should be based on these three wear stages.

  20. Effect of the Crystallization Process on the Marginal and Internal Gaps of Lithium Disilicate CAD/CAM Crowns

    Directory of Open Access Journals (Sweden)

    Jae-Hong Kim

    2016-01-01

    Full Text Available The aim of this study is to quantify the effect of the crystallization process on lithium disilicate ceramic crowns fabricated using a computer-aided design/computer-aided manufacturing (CAD/CAM system and to determine whether the effect of crystallization is clinically acceptable by comparing values of fit before and after the crystallization process. The mandibular right first molar was selected as the abutment for the experiments. Fifteen working models were prepared. Lithium disilicate crowns appropriate for each abutment were prepared using a commercial CAD/CAM system. Gaps in the marginal area and 4 internal areas of each crown were measured twice—before and after crystallization—using the silicone replica technique. The mean values of fit before and after crystallization were analyzed using a paired t-test to examine whether the conversion that occurred during crystallization affected marginal and internal gaps (α=0.05. Gaps increased in the marginal area and decreased in the internal areas after crystallization. There were statistically significant differences in all of the investigated areas (P<0.05. None of the values for marginal and internal fit of lithium disilicate CAD/CAM crowns after crystallization exceeded 120 μm, which is the clinically acceptable threshold.

  1. Effect of the Crystallization Process on the Marginal and Internal Gaps of Lithium Disilicate CAD/CAM Crowns.

    Science.gov (United States)

    Kim, Jae-Hong; Oh, Seunghan; Uhm, Soo-Hyuk

    2016-01-01

    The aim of this study is to quantify the effect of the crystallization process on lithium disilicate ceramic crowns fabricated using a computer-aided design/computer-aided manufacturing (CAD/CAM) system and to determine whether the effect of crystallization is clinically acceptable by comparing values of fit before and after the crystallization process. The mandibular right first molar was selected as the abutment for the experiments. Fifteen working models were prepared. Lithium disilicate crowns appropriate for each abutment were prepared using a commercial CAD/CAM system. Gaps in the marginal area and 4 internal areas of each crown were measured twice-before and after crystallization-using the silicone replica technique. The mean values of fit before and after crystallization were analyzed using a paired t-test to examine whether the conversion that occurred during crystallization affected marginal and internal gaps (α = 0.05). Gaps increased in the marginal area and decreased in the internal areas after crystallization. There were statistically significant differences in all of the investigated areas (P < 0.05). None of the values for marginal and internal fit of lithium disilicate CAD/CAM crowns after crystallization exceeded 120 μm, which is the clinically acceptable threshold. PMID:27123453

  2. Analysis of CVC roll contour and determination of roll crown

    Institute of Scientific and Technical Information of China (English)

    Guang Xu; Xianjun Liu; Jiarong Zhao; Junwei Xiong

    2007-01-01

    Mathematical analysis of continuous variable crown (CVC) roll contour used in CSP production line was conducted and the roll contour function of CVC roll was obtained. The validation with actual CVC roll contour shows that the calculation values of the roll contour function and the actual roll contour parameters given by equipment provider are the same, which proves that the roll contour function of CVC rolls given in this article is correct. The nonlinear relationship between the roll crown of CVC rolls and roll shift amounts was deduced. The concept of crown extremum was given.

  3. Crown lengthening procedure in the management of amelogenesis imperfecta.

    Science.gov (United States)

    Kalaivani, S; Manohar, Jenish; Shakunthala, P; Sujatha, S; Rajasekaran, S A; Karthikeyan, B; Kalaiselvan, S

    2015-08-01

    Full mouth rehabilitation includes a promising treatment planning and execution thus fulfilling esthetic, occlusal, and functional parameters maintaining the harmony of the stomatognathic system. Crown lengthening procedures have become an integral component of the esthetic armamentarium and are utilized with increasing frequency to enhance the appearance of restorations placed in the esthetic zone. Crown lengthening plays a role to create healthy relationship of the gingiva and bone levels so as to gain access to more of the tooth which can be restored, if it is badly worn, decayed or fractured, below the gum line. This paper highlights the full mouth crown lengthening procedure performed on a patient with amelogenesis imperfecta.

  4. Crown lengthening procedure in the management of amelogenesis imperfecta

    Science.gov (United States)

    Kalaivani, S.; Manohar, Jenish; Shakunthala, P.; Sujatha, S.; Rajasekaran, S. A.; Karthikeyan, B.; Kalaiselvan, S.

    2015-01-01

    Full mouth rehabilitation includes a promising treatment planning and execution thus fulfilling esthetic, occlusal, and functional parameters maintaining the harmony of the stomatognathic system. Crown lengthening procedures have become an integral component of the esthetic armamentarium and are utilized with increasing frequency to enhance the appearance of restorations placed in the esthetic zone. Crown lengthening plays a role to create healthy relationship of the gingiva and bone levels so as to gain access to more of the tooth which can be restored, if it is badly worn, decayed or fractured, below the gum line. This paper highlights the full mouth crown lengthening procedure performed on a patient with amelogenesis imperfecta. PMID:26538965

  5. Chromatographic zinc isotope separation by phenol formaldehyde benzo crown resin.

    Science.gov (United States)

    Ding, Xingcheng; Nomura, Masao; Suzuki, Tatsuya; Sugiyama, Yuichi; Kaneshiki, Toshitaka; Fujii, Yasuhiko

    2006-04-28

    New types of phenol formaldehyde resin having benzo crown as a functional group were synthesized and applied to zinc isotope chromatographic operation. Zinc adsorption and isotope separation capacities were dramatically improved by using phenol formaldehyde benzo-15-crown-5 resin. Zinc batch adsorption tests were performed by various dehydrated organic solvents. Separation coefficient, epsilon 8.1 x 10(-4) and height equivalent to a theoretical plate (HETP) 0.105 cm for the isotopic pair of 68Zn/64Zn in phenol formaldehyde benzo-15-crown-5 resin were obtained in the case of acetone as the solvent at 298+/-1K.

  6. INTEGRATION OF FLUORESCENCE DIFFERENTIAL PATH-LENGTH SPECTROSCOPY TO PHOTODYNAMIC THERAPY OF THE HEAD AND NECK TUMORS IS USEFUL IN MONITORING CLINICAL OUTCOME

    Directory of Open Access Journals (Sweden)

    Baris eKarakullukcu

    2015-04-01

    Full Text Available The use of fluorescence differential pathlength spectroscopy (FDPS has the potential to provide real-time information on photosensitiser pharmacokinetics, vascular physiology and photosensitizer photobleaching based dosimetry of tumors in the oral cavity receiving m-tetrahydroxyphenylchlorin (mTHPC photodynamic therapy (PDT. Reflectance spectra can be used provide quantitative values of oxygen saturation, blood volume fraction, blood vessel diameter, and to determine the local optical properties that can be used to correct raw fluorescence for tissue absorption. Patients and methods: Twenty-seven lesions in the oral cavity, either dysplasias or cancer were interrogated using FDPS, before and immediately after the therapeutic illumination. The average tumor center to normal mucosa ratio of fluorescence was 1.50 ± 0.66. mTHPC photobleaching was observed in 24 of the lesions treated. The average extent of photobleaching was 81% ± 17%. Information from FDPS spectroscopy coupled with the clinical results of the treatment identified 3 types of correctable errors in the application of mTHPC-PDT: Two patients exhibited very low concentrations of photosensitizer in tumour center, indicating an ineffective i.v. injection of photosensitiser or an erroneous systemic distribution of mTHPC. In one in tumor we observed no photobleaching accompanied by a high blood volume fraction in the illuminated tissue, suggesting that the presence of blood prevented therapeutic light reaching the target tissue. All 3 of the these lesions had no clinical response to PDT. In four patients we observed less than 50% photobleaching at the tumor margins , suggesting a possible geographic miss. One patient in this group had a recurrence within 2 months after PDT even though the initial response was good. The integration of FDPS to clinical PDT yields data on tissue physiology, photosensitiser content and photobleaching that can help identify treatment errors that can

  7. Integration of Fluorescence Differential Path-Length Spectroscopy to Photodynamic Therapy of the Head and Neck Tumors is Useful in Monitoring Clinical Outcome

    Science.gov (United States)

    Karakullukcu, Baris; Kanick, Stephen; Aans, Jan Bonne; Sterenborg, Henricus; Tan, Bing; Amelink, Arjen; Robinson, Dominic

    2015-04-01

    The use of fluorescence differential pathlength spectroscopy (FDPS) has the potential to provide real-time information on photosensitiser pharmacokinetics, vascular physiology and photosensitizer photobleaching based dosimetry of tumors in the oral cavity receiving m-tetrahydroxyphenylchlorin (mTHPC) photodynamic therapy (PDT). Reflectance spectra can be used provide quantitative values of oxygen saturation, blood volume fraction, blood vessel diameter, and to determine the local optical properties that can be used to correct raw fluorescence for tissue absorption. Patients and methods: Twenty-seven lesions in the oral cavity, either dysplasias or cancer were interrogated using FDPS, before and immediately after the therapeutic illumination. The average tumor center to normal mucosa ratio of fluorescence was 1.50 ± 0.66. mTHPC photobleaching was observed in 24 of the lesions treated. The average extent of photobleaching was 81% ± 17%. Information from FDPS spectroscopy coupled with the clinical results of the treatment identified 3 types of correctable errors in the application of mTHPC-PDT: Two patients exhibited very low concentrations of photosensitizer in tumour center, indicating an ineffective i.v. injection of photosensitiser or an erroneous systemic distribution of mTHPC. In one in tumor we observed no photobleaching accompanied by a high blood volume fraction in the illuminated tissue, suggesting that the presence of blood prevented therapeutic light reaching the target tissue. All 3 of the these lesions had no clinical response to PDT. In four patients we observed less than 50% photobleaching at the tumor margins , suggesting a possible geographic miss. One patient in this group had a recurrence within 2 months after PDT even though the initial response was good. The integration of FDPS to clinical PDT yields data on tissue physiology, photosensitiser content and photobleaching that can help identify treatment errors that can potentially be corrected.

  8. Crown lengthening procedure following intentional endodontic therapy for correction of supra-erupted posterior teeth: Case series with long-term follow-up

    Directory of Open Access Journals (Sweden)

    Shruti Arun Patil

    2016-01-01

    Full Text Available Context: The crown lengthening procedure (CLP is routinely carried out to correct gingival levels and achieve esthetic contours and adequate crown lengths for restorative purposes. Though the short-term outcomes have been found to be stable, long-term results are not much reported. Aims: To evaluate the long-term stability of the marginal bone levels, gingival levels, and the status of the teeth, which underwent endodontic therapy, followed by CLP and final restorations. Settings and Design: Institutional setting, long-term case series. Materials and Methods: Case records of the patients who underwent CLP and endodontic therapy for corrections of the supra-erupted teeth to regain the lost interocclusal spaces were retrieved, and the cases with complete set of the clinical and radiographs were taken. All the cases were recalled and bone levels on the radiographs, bleeding on probing, probing pocket depths, and changes in the soft tissue margins were evaluated. Statistical Analysis Used: Descriptive analysis. Results: A total of 25 teeth had undergone CLP and endodontic therapy and final restorations for a minimum of 24 months. The mean post-restorative duration was 50.8 ± 22.48 months (range 24–96 months. All the teeth were functional and asymptomatic with 100% survival. Interdental bone loss of 1 mm, probing pockets of 5 mm, and 1 mm buccal recession were observed in 16% of the sites. The amount of interocclusal space regained was adequate to restore the missing teeth in the opposing arch. Conclusions: The CLP is a predictive procedure for correction of supra-erupted teeth. The survival of the teeth that underwent the procedure in the present study was 100% over 24–96 months.

  9. Challenges in reconstructing an isolated anterior tooth with a metal-free crown

    Directory of Open Access Journals (Sweden)

    Max Doria Costa

    2013-01-01

    Full Text Available Introduction: Currently, new esthetic treatments are available to the dentist due to the advent of ceramic-ceramic prostheses. A new option has become part of daily clinical practice, with the promise of esthetic optimization through the elimination of metal in prosthetic crowns. The translucence of these new systems allows the transmission of light through the tooth structure, minimizing gingival darkness and producing a vibrant and natural appearance. Case Report: The patient, 30 years old, female, showed with a fractured tooth crown at the cervical level in the right lateral incisive. It was observed that the tooth had prior adequate endodontic treatment. A metal-free restorative system was selected. A plaster model was obtained for subsequent tooth preparative scanning and manufacture of ceramic framework. After receiving the framework, adjustments were made and the color choice of covering ceramic, following the protocol of choice for a chroma suboptimal aiming further characterization. After the ceramics application, adjustments in shape, texture, and occlusion were made. The crown was characterized by exterior paint, getting a favorable result, restoring esthetics and function. Discussion : The metal-free systems are a viable alternative to the restorative treatment when esthetics is desired, allowing a natural and harmonious smile, combined with the reliability of the restorative material.

  10. Stress distribution in implant-supported prostheses using different connection systems and cantilever lengths: digital photoelasticity.

    Science.gov (United States)

    Goiato, Marcelo Coelho; Shibayama, Ricardo; Gennari Filho, Humberto; de Medeiros, Rodrigo Antonio; Pesqueira, Aldiéris Alves; dos Santos, Daniela Micheline; de Araújo, Cleudmar Amaral

    2016-01-01

    Photoelastic analysis was used to evaluate the biomechanical behaviour of implant-supported, double-screwed crowns with different connection systems and cantilever lengths. Three models were made in PL-2 photoelastic resin and divided into six groups, on the basis of the implant connection system (external hexagon [EH] or Morse taper [MT]), type of abutment (Mini Pilar [Neodent, Curitiba, Paraná, Brazil] or "UCLA") and number of crowns in the cantilever (one or two). The implant-prosthesis unit was placed in a circular polariscope. Occlusal surfaces of the crowns were subjected to 100-N loads in the axial and oblique (45°) directions in a universal testing machine (EMIC). Generated stresses were recorded and analysed qualitatively in a graphics program (Adobe Photoshop). Under axial loading, all of the groups had similar numbers of fringes, which were increased when the crowns were subjected to oblique loading. The highest number of fringes was found during oblique loading in the EH + Mini Pilar group. In conclusion, although the type of implant connection system did not have a direct influence on the stress distribution for axial loading, the cantilever length did have a direct influence on stress distribution. Models with two crowns in the cantilever showed more stress, with a greater concentration of force on the cervical part of the implant. PMID:26783652

  11. Stress distribution in implant-supported prostheses using different connection systems and cantilever lengths: digital photoelasticity.

    Science.gov (United States)

    Goiato, Marcelo Coelho; Shibayama, Ricardo; Gennari Filho, Humberto; de Medeiros, Rodrigo Antonio; Pesqueira, Aldiéris Alves; dos Santos, Daniela Micheline; de Araújo, Cleudmar Amaral

    2016-01-01

    Photoelastic analysis was used to evaluate the biomechanical behaviour of implant-supported, double-screwed crowns with different connection systems and cantilever lengths. Three models were made in PL-2 photoelastic resin and divided into six groups, on the basis of the implant connection system (external hexagon [EH] or Morse taper [MT]), type of abutment (Mini Pilar [Neodent, Curitiba, Paraná, Brazil] or "UCLA") and number of crowns in the cantilever (one or two). The implant-prosthesis unit was placed in a circular polariscope. Occlusal surfaces of the crowns were subjected to 100-N loads in the axial and oblique (45°) directions in a universal testing machine (EMIC). Generated stresses were recorded and analysed qualitatively in a graphics program (Adobe Photoshop). Under axial loading, all of the groups had similar numbers of fringes, which were increased when the crowns were subjected to oblique loading. The highest number of fringes was found during oblique loading in the EH + Mini Pilar group. In conclusion, although the type of implant connection system did not have a direct influence on the stress distribution for axial loading, the cantilever length did have a direct influence on stress distribution. Models with two crowns in the cantilever showed more stress, with a greater concentration of force on the cervical part of the implant.

  12. Clinical significance of telomerase and its associate genes expression in the maintenance of telomere length in squamous cell carcinoma of the esophagus

    Institute of Scientific and Technical Information of China (English)

    Chung-Ping Hsu; Li-Wen Lee; Sen-Ei Shai; Chih-Yi Chen

    2005-01-01

    AIM: To observe the interaction between the expression of telomerase activity (TA) and its associate genes in regulation of the terminal restriction fragment length(TRFL) in esophageal squamous cell carcinoma (SCC).METHODS: Seventy-four specimens of esophageal SCC were examined. The TA was measured by telomeric repeat amplification protocol (TRAP) assay, and the associated genes [human telomerase-specific reverse transcriptase (hTERT), hTERC, TP1, c-Myc, TRF1,and TRF2] were detected using RT-PCR method. The TRFL was measured by Telomere Length Assay Kit and Southern blotting. The correlations between the expression of telomerase and its associated genes with the TRFL and survivals were examined.RESULTS: Expressions of the TA, hTERT, hTERC, TP1,c-Myc, TRF1, and TRF2 genes were observed in 85.1%,64.9%, 79.7%, 100.0%, 94.6%, 82.4%, and 91.9% of the tumor tissues, respectively. The TRFL of the tumor and normal esophageal tissues were 2.70±1.42 and 4.93±1.74 kb, respectively (P<0.0001). The TRFL of the telomerase positive and telomerase negative tumor tissues were 2.72±1.44 and 2.58±1.32 kb, respectively (P = 0.767).The TRFL ratios (TRFLR) of the telomerase positive and telomerase negative tumor tissues were 0.55±0.22 and 0.59±0.41, respectively (P = 0.742). The expression rates of h-TERT (P = 0.0002), hTERC (P<0.0001), and TRF1(P = 0.002) in the tumor tissues are higher than those of the normal paired tissues. Though TA is markedly activated in tumor tissues (P<0.0001), its expression is not related to clinicopathological parameters including gender, tumor differentiation, and TNM stages. The cumulative 4-year survival rates of telomerase positive and telomerase negative cases were 35.86% and 31.2%,respectively (P = 0.8442). The cumulative 4-year survival rates of patients with their TRFLR ≤85% and >85%were 38.7% and 15.7%, respectively (P = 0.1307).CONCLUSION: Though telomerase expression is not related to tumor stages and prognosis, our data support

  13. ATRAUMATIC SURGICAL EXTRUSION OF COMPLETE CROWN FRACTURED TOOTH USING PERIOTOME IN ESTHETIC ZONE: REPORT OF THREE CASES

    Directory of Open Access Journals (Sweden)

    Prashant

    2014-06-01

    Full Text Available BACKGROUND: Restoring traumatically injured teeth is a clinical challenge and often requires a multidisciplinary approach for predictable esthetic outcome. Although a number of techniques have been proposed for clinical crown lengthening procedures, all have some limitations in terms of function and esthetic. AIM: This report presents the clinical and radiographic results of surgical extrusion technique for clinical crown lengthening. MATERIAL & METHODS: Atraumatic surgical extrusion using a specially designed instrument (Periotome was performed in three cases in which it was expected that extensive respective osseous surgery would have to be used for crown lengthening. After luxation the teeth were extruded to the desired position and stabilized with sutures without rigid splinting. Two months after stabilization the teeth were treated by root canal treatment and firmly restored after 4months. RESULTS: Clinical examination performed after 6 months revealed probing depth ≤3mm around the teeth at all sites without bleeding on probing. Radiographs showed normal periodontal contour with new bone formation in periapical region without any evidence of root or crestal bone resorption or endodontic problems. CONCLUSION: The outcome of the treatment within a short duration has very good results without any esthetic and functional deformities.

  14. Laser all-ceramic crown removal and pulpal temperature--a laboratory proof-of-principle study.

    Science.gov (United States)

    Rechmann, P; Buu, N C H; Rechmann, B M T; Finzen, F C

    2015-11-01

    The objective of this proof-of-principle laboratory pilot study was to evaluate the temperature increase in the pulp chamber in a worst case scenario during Er:YAG laser debonding of all-ceramic crowns. Twenty extracted molars were prepared to receive all-ceramic IPS E.max CAD full contour crowns. The crowns were bonded to the teeth with Ivoclar Multilink Automix. Times for laser debonding and temperature rise in the pulp chamber using micro-thermocouples were measured. The Er:YAG was used with 560 mJ/pulse. The irradiation was applied at a distance of 5 mm from the crown surface. Additional air-water spray for cooling was utilized. Each all-ceramic crown was successfully laser debonded with an average debonding time of 135 ± 35 s. No crown fractured, and no damage to the underlying dentin was detected. The bonding cement deteriorated, but no carbonization at the dentin/cement interface occurred. The temperature rise in the pulp chamber averaged 5.4° ± 2.2 °C. During 8 out of the 20 crown removals, the temperature rise exceeded 5.5 °C, lasting 5 to 43 s (average 18.8 ± 11.6 s). A temperature rise of 11.5 °C occurred only once, while seven times the temperature rise was limited to 6.8 ± 0.5 °C. Temperature rises above 5.5 °C occurred only when the laser was applied from one side and additional cooling from the side opposite the irradiation. Er:YAG laser energy can successfully be used to efficiently debond all-ceramic crowns from natural teeth. Temperature rises exceeding 5.5 °C only occur when an additional air/water cooling from a dental syringe is inaccurately directed. To avoid possible thermal damage and to allow further heat diffusion, clinically temperature-reduced water might be applied.

  15. Influence of porcelain veneering on the marginal fit of Digident and Lava CAD/CAM zirconia ceramic crowns

    Science.gov (United States)

    Pak, Hyun-Soon; Han, Jung-Suk; Lee, Jai-Bong; Kim, Sung-Hun

    2010-01-01

    PURPOSE Marginal fit is a very important factor considering the restoration's long-term success. However, adding porcelain to copings can cause distortion and lead to an inadequate fit which exposes more luting material to the oral environment and causes secondary caries. The purpose of this study was to compare the marginal fit of 2 different all-ceramic crown systems before and after porcelain veneering. This study was also intended to verify the marginal fit of crowns originated from green machining of partially sintered blocks of zirconia (Lava CAD/CAM system) and that of crowns obtained through machining of fully sintered blocks of zirconia (Digident CAD/CAM system). MATERIALS AND METHODS 20 crowns were made per each system and the marginal fit was evaluated through a light microscope with image processing (Accura 2000) at 50 points that were randomly selected. Each crown was measured twice: the first measurement was done after obtaining a 0.5 mm coping and the second measurement was done after porcelain veneering. The means and standard deviations were calculated and statistical inferences among the 2 groups were made using independent t-test and within the same group through paired t-test. RESULTS The means and standard deviations of the marginal fit were 61.52 ± 2.88 µm for the Digident CAD/CAM zirconia ceramic crowns before porcelain veneering and 83.15 ± 3.51 µm after porcelain veneering. Lava CAD/CAM zirconia ceramic crowns showed means and standard deviations of 62.22 ± 1.78 µm before porcelain veneering and 82.03 ± 1.85 µm after porcelain veneering. Both groups showed significant differences when analyzing the marginal gaps before and after porcelain veneering within each group. However, no significant differences were found when comparing the marginal gaps of each group before porcelain veneering and after porcelain veneering as well. CONCLUSION The 2 all-ceramic crown systems showed marginal gaps that were within a reported clinically

  16. Fractal approach to computer-analytical modelling of tree crown

    International Nuclear Information System (INIS)

    In this paper we discuss three approaches to the modeling of a tree crown development. These approaches are experimental (i.e. regressive), theoretical (i.e. analytical) and simulation (i.e. computer) modeling. The common assumption of these is that a tree can be regarded as one of the fractal objects which is the collection of semi-similar objects and combines the properties of two- and three-dimensional bodies. We show that a fractal measure of crown can be used as the link between the mathematical models of crown growth and light propagation through canopy. The computer approach gives the possibility to visualize a crown development and to calibrate the model on experimental data. In the paper different stages of the above-mentioned approaches are described. The experimental data for spruce, the description of computer system for modeling and the variant of computer model are presented. (author). 9 refs, 4 figs

  17. Surgical crown lengthening: a periodontal and restorative interdisciplinary approach.

    Science.gov (United States)

    Parwani, Simran R; Parwani, Rajkumar N

    2014-01-01

    Surgical crown lengthening helps to provide an adequate retention form for proper tooth preparation, thus enabling dentists to create esthetically pleasing and healthy restorations. Long-term stability requires accurate diagnosis and development of a comprehensive treatment plan in each case. This sequence of events stresses the importance of communication between the restorative dentist and the periodontist. This article presents 2 cases that involve surgical crown lengthening (including mucoperiosteal flap and ostectomy) for the restoration of teeth.

  18. Point processes in forestry : an application to tree crown detection

    OpenAIRE

    Perrin, Guillaume; Descombes, Xavier; Zerubia, Josiane

    2006-01-01

    In this research report, we aim at extracting tree crowns from remotely sensed images using marked point processes of discs and ellipses. Our approach is indeed to consider that the data are some realizations of a marked point process. Once a geometrical object is defined, we sample a marked point process defined by a density with a Reversible Jump Markov Chain Monte Carlo dynamics and simulated annealing to get the maximum a posteriori estimator of the tree crown distribution on the image. I...

  19. An interdisciplinary approach to treat crown-root-fractured tooth

    OpenAIRE

    Ying Chun Sun; Ying Li; Jian Tong; Ping Gao

    2013-01-01

    Restoration of a crown-root subgingival fractured tooth, especially at anterior aesthetic zones is still a great challenge for restorative dentists. Crown lengthening procedure alone has the disadvantage of high gingival curve of the final restoration, which was not discontinuous to adjacent teeth and thus compromise cosmetic outcomes. The objective of this report is to display a new interdisciplinary approach which combining endodontic root canal treatment, orthodontic extrusion, periodontal...

  20. The analysis of the application of crown lengthening surgery in the dental restoration of traumatic anterior teeth%牙冠延长术在外伤前牙修复中的临床应用

    Institute of Scientific and Technical Information of China (English)

    刘赟; 高婵; 吴佩; 汪春仙; 熊贵忠; 刘心

    2014-01-01

    Objective:To investigate the clinical efficacy of crown lengthening of shortening or subgingival teeth on restoration of the traumatic anterior. Method:The front 50 teeth choice of trauma cases after loosening degree less than or e-qual to the first degree,subgingival crown fracture was above or equal 3 mm,after complete periodontal therapy,using method of flap combined with excision of bone turnover and root crown repositioned flap operation for lengthening surgery, routine repair in patients according to their oral cavity after 4~6 weeks operation. Result:All traumatic anterior teeth after operation may obtain enough clinical crown length,which resulting ferrule effect effective. Follow-up with traumatic anterior teeth after operation,gingival color is normal,its height is adjust with neighbor teeth,and all coordination is meet with crown edge sealing. Patient is satisfy with the function and elegant appearance of the traumatic anterior teeth after operation. Con-clusion:Crown lengthening is great significance of successful repair surgery of traumatic anterior teeth. In the process of op-eration and repair,we need to pay further attention to detail and time selection of repair surgery.%目的:探讨牙冠延长术在外伤前牙牙冠过短或缺损至龈下的患牙进行修复的临床疗效。方法:选择外伤后松动度≤Ⅰ度,牙冠折断至龈下≥3 mm的前牙52颗,对患牙完成根管治疗及牙周基础治疗后,采用翻瓣联合骨切除的方法及根向复位瓣手术行牙冠延长术,术后4~6周根据患者的口腔情况进行常规桩核冠修复。结果:所有患牙术后获得足够的临床冠长度,残根断端产生有效的箍效应。术后对患牙进行跟踪随访,患牙龈缘色泽正常、高度与邻牙相协调、全冠边缘密合。患者对患牙的功能、美观满意。结论:牙冠延长术对于外伤前牙的成功修复有重要意义,治疗过程中应注重手术的细节及修复时机的选择。

  1. The Convergence Angle of Full-coverage Crown Preparations Made by Dental Students

    Directory of Open Access Journals (Sweden)

    R. Baghai Naini

    2008-03-01

    Full Text Available Objective: A clinically feasible convergence angle in full-coverage crown preparations, meeting the requirements for proper retention and resistance forms, has always been a matter of interest for laboratory and clinical researches. This study aims to evaluate the angle in teeth prepared by both under- and post-graduate students at Tehran University of Medical Sciences, Faculty of dentistry, Department of Prosthodontics.Materials and Methods: Samples consisted of 196 prepared teeth for full-coverage crown restoration by third year postgraduate and fifth year undergraduate students in the Department of Prosthodontics. Two images were obtained from each die by a scanner and both bucco-lingual and mesio-distal convergence angles were measured, by two different assessors, via Auto CAD 14 software. The data were analyzed using analysis of variance.Results: There were statistically significant differences between the teeth prepared by un-der- and post-graduate students in mesio-distal convergence angles of all maxillary teeth, except for canines. Significant differences were found between bucco-lingual convergence angles of the maxillary canines and molars.Conclusion: The recently recommended convergence angles are more clinically feasible compared to the classic 4 to 10 degrees that was previously suggested for all teeth. It also seems that clinical experience does not necessarily lead to a decrease in convergence an-gles during preparation.

  2. Consequences of crown shortening canine teeth in Greenland sled dogs

    DEFF Research Database (Denmark)

    Kortegaard, H E; Anthony Knudsen, T; Dahl, S;

    2015-01-01

    OBJECTIVES: To evaluate the consequences of crown shortening, focusing on the prevalence of pulp exposure and periapical pathology in Greenland sled dogs that had had their canine crowns shortened at an early age. METHODS: Five cadaver heads and 54 sled dogs underwent an oral examination for dental...... fractures and pulp exposure of canines. All canines were radiographed and evaluated for periapical pathology. RESULTS: The prevalence of canine pulp exposure in 12 (5 heads and 7 dogs) crown shortened dogs was 91 · 7%, and 21 · 3% in 47 not-crown shortened dogs. A significant (P ... exposure of the canines in the crown shortened group compared to the not-crown shortened group was seen with a relative risk of 4 · 3 on a dog basis and a relative risk of 12 · 2 on a tooth basis. In dogs with pulp exposure of canines (n = 51) the prevalence of periapical pathology was 82 · 4%, but only 0...

  3. Smart Crown 技术的研究与应用%Study and Application of Smart Crown Technology

    Institute of Scientific and Technical Information of China (English)

    王振华; 王玲珑; 焦广亮

    2012-01-01

    The work principle and technological characteristics of Smart Crown profile control technology were introduced. The roll equivalent crown equation was deduced by Smart Crown roll shape curve equivalent. Production practice proves that the plate profile control capability is greatly improved, roll wear is uniformity and working time is longer after using Smart Crown technology.%介绍了Smart Crown板形控制技术的原理及技术特点,根据Smart Crown辊型曲线方程推导了轧辊等效凸度方程.生产实践证明,使用Smart Crown工作辊后,轧机板形控制能力显著提高,轧辊磨损均匀,工作周期显著延长.

  4. Evaluation of fracture resistance of indirect composite resin crowns by cyclic impact test: influence of crown and abutment materials.

    Science.gov (United States)

    Sakoguchi, Kenji; Minami, Hiroyuki; Suzuki, Shiro; Tanaka, Takuo

    2013-01-01

    This study evaluated the effect of abutment materials on the fracture resistance of composite crowns for premolars. Composite crowns were fabricated using two different indirect composite resin materials (Meta Color Prime Art or Estenia C&B) and cemented onto either a metal (Castwell M.C. 12) or composite resin (Build-It FR and FibreKor) abutment with resin cement (Panavia F2.0). Twenty-four specimens were fabricated for four groups (n=6 each) and subjected to 280-N cyclic impact loading at 1.0 Hz. The number of cycles which caused the composite crown to fracture was defined as its fracture resistance. All data were statistically analyzed using ANOVA and the Bonferroni test (α=0.05). Composite crowns cemented onto resin abutments showed higher fracture resistance than those cemented onto metal abutments.

  5. Microbiological and microscopic analysis of the pulp of non-vital traumatized teeth with intact crowns

    Directory of Open Access Journals (Sweden)

    Kely Firmino Bruno

    2009-10-01

    Full Text Available OBJECTIVE: This study evaluated the presence of microorganisms and analyzed microscopically the pulp of 20 traumatized human teeth with intact crowns and clinical diagnosis of pulp necrosis, based on the association of at least three of the clinical criteria: crown discoloration, negative response to thermal and electric pulp vitality tests, positive response to vertical and horizontal percussion, pain on palpation or mobility. MATERIAL AND METHODS: Microbiological collection was performed from the root canals to evaluate the presence of microorganisms. The pulp samples were stained with hematoxylin and eosin (H.E. for histological evaluation of possible morphological alterations. RESULTS: Analysis of results was performed by statistical tests (linear regression test and diagnostic analysis and subjective analysis of the sections stained with H.E. and revealed that only 15% of the sample did not exhibit microbial development. The time elapsed between dental trauma and onset of endodontic intervention ranged from 15 days to 31 months; the percussion test presented high sensitivity (80% for detection of microorganisms in the root canal of traumatized teeth; 3 teeth (15% did not present pulp tissue, being characterized as complete autolysis; analysis of pulp samples was performed on the other 17 cases, among which 3 (15% exhibited partial necrosis without possibility of repair and 14 presented complete necrosis; none of the clinical criteria employed for the diagnosis of pulp necrosis in traumatized teeth was pathognomonic. CONCLUSIONS: The present results allowed the following conclusions: with regard to microbiological findings, 85% of teeth presented microorganisms in the root canal, despite the presence of an intact crown. Concerning the microscopic findings, 100% of traumatized teeth presented pulp necrosis; the pulp vitality tests based on pulp response to heat, cold and vertical percussion were the most reliable to diagnose pulp necrosis in

  6. Comparative photophysical behaviour of naphthalene-linked crown ethers and aza crown ethers of varying cavity dimensions

    Indian Academy of Sciences (India)

    Subhodip Samanta; Pinki Saha Sardar; Shyam Sundar Maity; Anirban Pal; Maitrayee Basu Roy; Sanjib Ghosh

    2007-03-01

    A comparative time-resolved emission studies of several naphtho-crown ethers I-V, where metal ions can be complexed in a predetermined orientation with respect to the naphthalene (Naph) - plane and naphthalene-linked aza crown ethers (L1 and L2) have been presented. In both the systems, crown ethers and aza crown ethers, naphthalene fluorescence gets quenched. In the systems I to V, the quenching is mainly due to efficient spin-orbit coupling (SOC) leading to greater population of the lowest triplet state of naphthalene. This SOC depends on the orientation of the crown ring with respect to the Naph--plane. However, in the systems L1 and L2, the quenching is due to photoinduced electron transfer (PET) from nitrogen lone pair of the aza crown ring to naphthalene moiety and consequent exciplex formation. The results have been interpreted using the time-resolved emission studies of all the compounds in various solvents, their alkali metal ion complexes, and protonated ligands.

  7. Measuring Thermodynamic Length

    Energy Technology Data Exchange (ETDEWEB)

    Crooks, Gavin E

    2007-09-07

    Thermodynamic length is a metric distance between equilibrium thermodynamic states. Among other interesting properties, this metric asymptotically bounds the dissipation induced by a finite time transformation of a thermodynamic system. It is also connected to the Jensen-Shannon divergence, Fisher information, and Rao's entropy differential metric. Therefore, thermodynamic length is of central interestin understanding matter out of equilibrium. In this Letter, we will consider how to denethermodynamic length for a small system described by equilibrium statistical mechanics and how to measure thermodynamic length within a computer simulation. Surprisingly, Bennett's classic acceptance ratio method for measuring free energy differences also measures thermodynamic length.

  8. Retention of esthetic veneers on primary stainless steel crowns.

    Science.gov (United States)

    Baker, L H; Moon, P; Mourino, A P

    1996-01-01

    The purpose of this study was to ascertain the amount of shearing force necessary to fracture, dislodge or deform the esthetic veneer facings of four commercially available veneered primary incisor stainless steel crowns. The four types tested were: Cheng Crowns, [Peter Cheng Orthodontic Laboratory]; Whiter Biter Crown II, [White Bite Inc.]; Kinder Krowns, [Mayclin Dental Studio, Inc]; and NuSmile Primary Crowns, [Orthodontic Technologies, Inc]. The crowns (#4 right central incisor) from each manufacturer were obtained with the facings attached. The crowns were soaked for ninety days and thermocycled at 4 degrees C and 55 degrees C for 500 45-second cycles. The crowns were cemented to standardized chromium cobalt metal dies. Each die was placed in to a custom holder on the Instron Universal testing machine. A force was applied at the incisal edge of the veneer at 148 degrees, (the primary interincisal angle), with a crosshead speed of 0.05 inches/minute until the veneer either fractured, dislodged or deformed. The mean force (Ibs) required +/- SD to produce failure, in descending order, was as follows: Cheng (107.8 +/- 17.3); NuSmile (100.2 +/- 18.2); KinderKrown (91.3 +/- 27.4)d Whiter Biter (81.5 +/- 21.7). To test the hypothesis of no difference among the four manufacturers, an analysis of variance was performed using PROC GLM. The resultant F statistic was 2.79 (p < 0.0543), indicating a marginally statistically significant difference in the response variable "pressure" among the four groups. A posthoc test was then performed to ascertain where these differences occurred. These results, using Turkey's studentized range test for pairwise comparisons, suggested that the only difference was between the Cheng and Whiter Biter manufacturers. PMID:8853822

  9. The fit of crowns produced using digital impression systems.

    Science.gov (United States)

    Vennerstrom, Micael; Fakhary, Mobin; Von Steyern, Per Vult

    2014-01-01

    Compare the marginal and internal fit of crowns manufactured using four different digital impression systems with crowns manufactured using conventional impression technique, that served as a control group. Fifty all-ceramic crowns were fabricated using 50 standardized dies divided into five groups, each group representing one impression system. Each crown was cemented onto its respective model and sectioned into four segments.The marginal and internal fit were measured at 8 predefined points. A total of 1567 measurements were made, statistically analyzed and compared with crowns fabricated using the five systems. The following was found: (1) No significant difference was found with regard to mar ginal gap when comparing the control group to any of the digital systems. (2) Lava™ had smaller marginal gaps than CEREC® and iTero®, (3) CEREC and Lava had smaller gaps in the chamfer compared to iTero and the control, (4) E4D® showed smaller gaps than CEREC at measuring points 4-8 and CEREC a smaller gap at point 2, (5) Lava showed smaller gaps than CEREC at measuring points 1,3 and 5-8. (6) Lava had smaller gaps than iTero at measuring points 1-4,7 and 8. All differences presented were significant. In conclusions, crowns manufactured using digital impressions present a marginal and internal fit equal to, or better than, crowns made using a conventional impression method.The marginal and internal fit of reconstructions made using digital impression techniques could improve with a lower initial setting of the spacer.

  10. Apical crown technique to model canal roots. A review of the literature.

    Science.gov (United States)

    Tortini, D; Colombo, M; Gagliani, M

    2007-09-01

    The goals of endodontic therapy are to shape and clean the root canal system in order to receive a three-dimensional and hermetic filling of the entire endodontic space. The aim of this review is to analyze the development of the different canal shaping techniques from the manual stainless-steel instruments to the recently developed rotary Ni-Ti systems. The need to provide instruments of a suitable size to reach the apex of curved root canals drove the development of preparation techniques with a greater focus on the apical part. The Crown-Down technique involves the widening of the canal orifices with Gates-Glidden drills followed by the incremental removal of organic canal contents proceeding from the canal orifice to the apical portion using manual files. Files are used from larger to smaller with no apical pressure. Nevertheless, the term ''Crown-Down'' does not define the technique in the strictest sense, nor does it provide a specific sequence for the use of instruments, but rather defines a way to use the instruments. The preparation of root canals has been revolutionised by the development of Ni-Ti alloys. The features of this alloy give instruments profound flexibility and allow the manufacture of more tapered instruments compared with traditional stainless-steel instruments. In the second part of this review, numerous examples are provided concerning the comparison between different Ni-Ti systems and their techniques for use. A Crown-Down approach provides certain advantages including early organic debris removal, the creation of a large reservoir for irrigating solutions, a straighter access to the apical region of curved canals, and greater precision with regard to the exact working length and apical size.

  11. Influence of mandibular length on mouth opening

    NARCIS (Netherlands)

    Dijkstra, PU; Hof, AL; Stegenga, B; De Bont, LGM

    1999-01-01

    Theoretically, mouth opening not only reflects the mobility of the temporomandibular joints (TMJs) but also the mandibular length. Clinically, the exact relationship between mouth opening, mandibular length, and mobility of TMJs is unclear. To study this relationship 91 healthy subjects, 59 women an

  12. Intensive field phenotyping of maize (Zea mays L.) root crowns identifies phenes and phene integration associated with plant growth and nitrogen acquisition.

    Science.gov (United States)

    York, Larry M; Lynch, Jonathan P

    2015-09-01

    Root architecture is an important regulator of nitrogen (N) acquisition. Existing methods to phenotype the root architecture of cereal crops are generally limited to seedlings or to the outer roots of mature root crowns. The functional integration of root phenes is poorly understood. In this study, intensive phenotyping of mature root crowns of maize was conducted to discover phenes and phene modules related to N acquisition. Twelve maize genotypes were grown under replete and deficient N regimes in the field in South Africa and eight in the USA. An image was captured for every whorl of nodal roots in each crown. Custom software was used to measure root phenes including nodal occupancy, angle, diameter, distance to branching, lateral branching, and lateral length. Variation existed for all root phenes within maize root crowns. Size-related phenes such as diameter and number were substantially influenced by nodal position, while angle, lateral density, and distance to branching were not. Greater distance to branching, the length from the shoot to the emergence of laterals, is proposed to be a novel phene state that minimizes placing roots in already explored soil. Root phenes from both older and younger whorls of nodal roots contributed to variation in shoot mass and N uptake. The additive integration of root phenes accounted for 70% of the variation observed in shoot mass in low N soil. These results demonstrate the utility of intensive phenotyping of mature root systems, as well as the importance of phene integration in soil resource acquisition.

  13. Predicting tree crown defoliation using color-infrared orthophoto maps

    Directory of Open Access Journals (Sweden)

    Eigirdas M

    2013-01-01

    Full Text Available Orthophoto maps based on color-infrared aerial photography have been used by the Lithuanian forest inventory since 2001. This study aimed to investigate the opportunities for using these orthophoto maps to predict tree crown defoliation at the single tree and sample plot levels. The test area was located in the Aukstaitija National Park, eastern Lithuania, and it was photographed in the summer of 2008 using a Vexcel UltraCam D digital frame aerial camera to produce digital orthophoto maps with a 0.5 x 0.5 m ground sampling density. Some 1721 tree crowns (mainly pine, spruce and birch, located in 166 permanent sample plots, were identified and delineated on the orthophoto maps. Crown defoliation and other dendrometric characteristics were field-estimated for all of these trees in summer 2008. Judgments on the suitability of using color-infrared aerial photography based orthophotos to estimate tree crown defoliation were based on the accuracy of the defoliation prediction. Defoliation for each crown was predicted using the non-parametric k-Nearest Neighbor (k-NN method and characteristics extracted from the digital orthophoto maps as the auxiliary variables for prediction. Prediction accuracies were validated using the “Leave One Out” technique by comparing the predicted data with data from field-assessed crown defoliations. The lowest root mean square errors for the predicted tree crown defoliation values were 7.564 for pine trees, 9.166 for spruce and 7.712 for birch and the highest coefficients of correlation between field-estimated and predicted crown defoliations were 0.576, 0.600 and 0.386, respectively. However, there was no best performing solution for using the k-NN prediction found, as the best results were achieved using different approaches. Next, predicted and field estimated tree crown defoliation values were aggregated up to the sample plot level by taking an averaging of trees in the same sample plot. The root mean square error

  14. Crown sealing and buckling instability during water entry of spheres

    KAUST Repository

    Marston, J. O.

    2016-04-05

    We present new observations from an experimental investigation of the classical problem of the crown splash and sealing phenomena observed during the impact of spheres onto quiescent liquid pools. In the experiments, a 6 m tall vacuum chamber was used to provide the required ambient conditions from atmospheric pressure down to of an atmosphere, whilst high-speed videography was exploited to focus primarily on the above-surface crown formation and ensuing dynamics, paying particular attention to the moments just prior to the surface seal. In doing so, we have observed a buckling-type azimuthal instability of the crown. This instability is characterised by vertical striations along the crown, between which thin films form that are more susceptible to the air flow and thus are drawn into the closing cavity, where they atomize to form a fine spray within the cavity. To elucidate to the primary mechanisms and forces at play, we varied the sphere diameter, liquid properties and ambient pressure. Furthermore, a comparison between the entry of room-temperature spheres, where the contact line pins around the equator, and Leidenfrost spheres (i.e. an immersed superheated sphere encompassed by a vapour layer), where there is no contact line, indicates that the buckling instability appears in all crown sealing events, but is intensified by the presence of a pinned contact line. © 2016 Cambridge University Press.

  15. An interdisciplinary approach to reconstruct a fractured tooth under an intact all ceramic crown: Case report with four years follow up

    Directory of Open Access Journals (Sweden)

    Sudhir Bhandari

    2011-01-01

    Full Text Available Trauma causing the fracture of a restored tooth with the extracoronal full coverage prosthesis remaining intact is a common occurrence in dental practice. Reconstruction of the damaged tooth foundation and recementation of the crown can pose quite a challenge for the restorative dentist. This case report describes an innovative interdisciplinary chairside technique for the recementation of an all-ceramic crown on a fractured maxillary central incisor. The course of care described is effective, affordable, and saves time in comparison with other treatment options for such clinical situations.

  16. Crown-formation time of a fossil hominid premolar tooth.

    Science.gov (United States)

    Beynon, A D; Dean, M C

    1987-01-01

    Studies using surface or internal enamel growth indicators in hominids have suggested that crown-formation times were shorter than those in modern man. The crown-formation time in a robust australopithecine premolar tooth was calculated by counting enamel cross-striations, which correspond to daily increments of formation, on a replica of the fractured internal enamel surface of cuspal enamel using scanning electron microscopy. Cervical enamel completion time was estimated using other growth indicators including striae, and using measured and calculated cross-striation repeat intervals, giving a completion time of approx. 2.4 yr. This is much shorter than reported premolar crown formation times in modern man. These findings support the concept of an abbreviated period of dental development, with implications on the duration of the growth period in early hominids. PMID:3130039

  17. Effect of screw access hole preparation on fracture load of implant-supported zirconia-based crowns: an in vitro study.

    Science.gov (United States)

    Mokhtarpour, Hadi; Eftekhar Ashtiani, Reza; Mahshid, Minoo; Tabatabaian, Farhad; Alikhasi, Marzieh

    2016-01-01

    Background. Fracture load of implant-supported restorations is an important factor in clinical success. This study evaluated the effect of two techniques for screw access hole preparation on the fracture load of cement-screw-retained implant-supported zirconia-based crowns. Methods. Thirty similar cement-screw-retained implant-supported zirconia-based maxillary central incisor crowns were evaluated in three groups of 10. Group NH: with no screw access holes for the control; Group HBS: with screw access holes prepared with a machine before zirconia sintering; Group HAS: with screw access holes prepared manually after zirconia sintering. In group HBS, the access holes were virtually designed and prepared by a computer-assisted design/computer-assisted manufacturing system. In group HAS, the access holes were manually prepared after zirconia sintering using a diamond bur. The dimensions of the screw access holes were equal in both groups. The crowns were cemented onto same-size abutments and were then subjected to thermocycling. The fracture load values of the crowns were measured using a universal testing machine. Data were analyzed with ANOVA and Tukey test (P implant-supported zirconia-based crowns decreased the fracture load. PMID:27651885

  18. Effect of screw access hole preparation on fracture load of implant-supported zirconia-based crowns: an in vitro study

    Science.gov (United States)

    Mokhtarpour, Hadi; Eftekhar Ashtiani, Reza; Mahshid, Minoo; Tabatabaian, Farhad; Alikhasi, Marzieh

    2016-01-01

    Background. Fracture load of implant-supported restorations is an important factor in clinical success. This study evaluated the effect of two techniques for screw access hole preparation on the fracture load of cement-screw-retained implant-supported zirconia-based crowns. Methods. Thirty similar cement-screw-retained implant-supported zirconia-based maxillary central incisor crowns were evaluated in three groups of 10. Group NH: with no screw access holes for the control; Group HBS: with screw access holes prepared with a machine before zirconia sintering; Group HAS: with screw access holes prepared manually after zirconia sintering. In group HBS, the access holes were virtually designed and prepared by a computer-assisted design/computer-assisted manufacturing system. In group HAS, the access holes were manually prepared after zirconia sintering using a diamond bur. The dimensions of the screw access holes were equal in both groups. The crowns were cemented onto same-size abutments and were then subjected to thermocycling. The fracture load values of the crowns were measured using a universal testing machine. Data were analyzed with ANOVA and Tukey test (P zirconia-based crowns decreased the fracture load. PMID:27651885

  19. Effect of various putty-wash impression techniques on marginal fit of cast crowns.

    Science.gov (United States)

    Nissan, Joseph; Rosner, Ofir; Bukhari, Mohammed Amin; Ghelfan, Oded; Pilo, Raphael

    2013-01-01

    Marginal fit is an important clinical factor that affects restoration longevity. The accuracy of three polyvinyl siloxane putty-wash impression techniques was compared by marginal fit assessment using the nondestructive method. A stainless steel master cast containing three abutments with three metal crowns matching the three preparations was used to make 45 impressions: group A = single-step technique (putty and wash impression materials used simultaneously), group B = two-step technique with a 2-mm relief (putty as a preliminary impression to create a 2-mm wash space followed by the wash stage), and group C = two-step technique with a polyethylene spacer (plastic spacer used with the putty impression followed by the wash stage). Accuracy was assessed using a toolmaker microscope to measure and compare the marginal gaps between each crown and finish line on the duplicated stone casts. Each abutment was further measured at the mesial, buccal, and distal aspects. One-way analysis of variance was used for statistical analysis. P values and Scheffe post hoc contrasts were calculated. Significance was determined at .05. One-way analysis of variance showed significant differences among the three impression techniques in all three abutments and at all three locations (P < .001). Group B yielded dies with minimal gaps compared to groups A and C. The two-step impression technique with 2-mm relief was the most accurate regarding the crucial clinical factor of marginal fit.

  20. Uniform versus asymmetric shading mediates crown recession in conifers.

    Directory of Open Access Journals (Sweden)

    Amanda L Schoonmaker

    Full Text Available In this study we explore the impact of asymmetrical vs. uniform crown shading on the mortality and growth of upper and lower branches within tree crowns, for two conifer species: shade intolerant lodgepole pine (Pinus contorta and shade tolerant white spruce (Picea glauca. We also explore xylem hydraulics, foliar nutrition, and carbohydrate status as drivers for growth and expansion of the lower and upper branches in various types of shading. This study was conducted over a two-year period across 10 regenerating forest sites dominated by lodgepole pine and white spruce, in the lower foothills of Alberta, Canada. Trees were assigned to one of four shading treatments: (1, complete uniform shading of the entire tree, (2 light asymmetric shading where the lower 1/4-1/3 of the tree crown was shaded, (3 heavy asymmetric shading as in (2 except with greater light reduction and (4 control in which no artificial shading occurred and most of the entire crown was exposed to full light. Asymmetrical shading of only the lower crown had a larger negative impact on the bud expansion and growth than did uniform shading, and the effect was stronger in pine relative to spruce. In addition, lower branches in pine also had lower carbon reserves, and reduced xylem-area specific conductivity compared to spruce. For both species, but particularly the pine, the needles of lower branches tended to store less C than upper branches in the asymmetric shade, which could suggest a movement of reserves away from the lower branches. The implications of these findings correspond with the inherent shade tolerance and self-pruning behavior of these conifers and supports a carbon based mechanism for branch mortality--mediated by an asymmetry in light exposure of the crown.

  1. Synthesis and adsorption properties of chitosan-crown ether resins

    Institute of Scientific and Technical Information of China (English)

    彭长宏; 陈艺锋; 唐谟堂

    2003-01-01

    Two kinds of novel chitosan-crown ether resins, Schiff base type chitosan-benzo-15-crown-5 (CTS-B15)and chitosan-benzo-18-crown-6 (CTS-B18), were synthesized through the reaction between -NH2 in chitosan and -CHO in 4′-formyl benzo-crown ethers. Their structures were characterized by elemental analysis and FT-IR spectra analysis. The elemental analysis results show that the mass fractions of nitrogen in CTS-B15 and CTS-B18 are much lower than those of chitosan. The results of FT-IR spectra of CTS-B15 and CTS-B18 reveal that there exist characteristic peak of C= N, N-H and Ar, and characteristic peak of pyr anoside in the chain of chitosan-crown ether resins, showing that the structures of chitosan-crown ethers are as expected. The adsorption properties of CTS-B15 and CTS-B18 for Pd2+ , Cu2 + and Hg2+ were studied and the experimental results show that these adsorbents have both good adsorption characterization and especially high particular adsorption selectivity for Pd2+ when Cu2+ and Hg2+ are in coexistence, and the coefficients of selectivity of CTS-B15 and CTS-B18 for metal ions are KPd2+/cu2+ =7.56, KPd2+/Hg2+ = 68.00, Kcu2+/Hg2+ = 9.00 and KPd2+/cu2+ = 6.00, KPd2+/Hg2+ = 19. 00, Kcu2+/Hg2+ = 3.00, respectively.

  2. Evaluation of the onset of failure under mechanical and thermal stresses on luting agent for metal-ceramic and metal crowns by finite element analysis

    Directory of Open Access Journals (Sweden)

    Hema Agnihotri

    2010-01-01

    Full Text Available Long-term clinical failures of cemented prosthesis depend, to a large extent, on the integrity of the luting agent. The causative factors that lead to microfracture and, hence, failure of the luting agents are the stresses acting inside the oral cavity. Therefore, the present study was designed to develop an understanding of the relationship between stresses in the tooth and the failure potential of the luting agent. Two-dimensional finite element stress analysis was performed on the mandibular second premolar. The behavior of zinc-phosphate and glass-ionomer were studied under different crowns (metal-ceramic and metal crown and loading conditions (mechanical force of 450 N acting vertically over the occlusal surface, thermal loads of 60° and 0°C. It was observed from the study that failure threshold of the luting agent was influenced both by the elastic modulus of the luting agent and by the type of the crown.

  3. Museum security and the Thomas Crown Affair.

    Energy Technology Data Exchange (ETDEWEB)

    Michaud, E. C. (Nuclear Engineering Division)

    2010-01-01

    Over the years, I've daydreamed about stealing a Vermeer, a Picasso, or Rembrandt. It tickles me, as much as watching the reboot of The Thomas Crown Affair. Why is it, do you suppose, so much fun to think about stealing a world renowned piece off the wall of a major metropolitan museum? Is it the romantic thoughts of getting away with it, walking past infrared detectors, and pressure sensors ala Indiana Jones with the sack of sand to remove the idol without triggering the security system? Is it the idea of snatching items with such fantastic prices, where the romance of possessing an item of such value is less intoxicating than selling it to a private collector for it to never be seen again? I suspect others share my daydreams as they watch theater or hear of a brazen daylight heist at museums around the world, or from private collections. Though when reality sets in, the mind of the security professional kicks in. How could one do it, why would one do it, what should you do once it's done? The main issue a thief confronts when acquiring unique goods is how to process or fence them. They become very difficult to sell because they are one-of-a-kind, easy to identify, and could lead to the people involved with the theft. The whole issue of museum security takes up an ironic twist when one considers the secretive British street artist 'Banksy'. Banksy has made a name for himself by brazenly putting up interesting pieces of art in broad daylight (though many critics don't consider his work to be art) on building walls, rooftops, or even museums. I bring him up for a interesting take on what may become a trend in museum security. In March of 2005, Banksy snuck a piece of his called 'Vandalized Oil Painting' into the Brooklyn Museum's Great Historical Painting Wing, plus 3 other pieces into major museums in New York. Within several days, 2 paintings had been torn down, but 2 stayed up much longer. In his home country of the UK, a

  4. Synthesis of Schiff Base Calix[4]arene Crowns

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    This letter reports the synthesis of Schiff base calix[4]arene crowns containing m-xylylene phenol subunit, in which calix[4]arene Schiff base crowns 2a, 2b and 2c were formed by 1:1 condensation of calix[4]arene diamine 1 with dialdehydes (2, 6-diformyl-4-chlorophenol 3a, 2, 6-diformyl-4-methylphenol 3b, 2, 6-diformyl-4-tert-butylphenol 3c) under high dilute condition in refluxing anhydrous ethanol in 65-70% yield.

  5. CROWN: A service grid middleware with trust management mechanism

    Institute of Scientific and Technical Information of China (English)

    HUAI Jinpeng; HU Chunming; LI Jianxin; SUN Hailong; WO Tianyu

    2006-01-01

    Based on a proposed Web service-based grid architecture, a service grid middleware system called CROWN is designed in this paper. As the two kernel points of the middleware, the overlay-based distributed grid resource management mechanism is proposed, and the policy-based distributed access control mechanism with the capability of automatic negotiation of the access control policy and trust management and negotiation is also discussed in this paper. Experience of CROWN testbed deployment and application development shows that the middleware can support the typical scenarios such as computing-intensive applications, data-intensive applications and mass information processing applications.

  6. Immediate esthetic crown with a facet of the extracted element.

    Science.gov (United States)

    Di Giacomo, Giovanni de Almeida Prado; Magalhães, Amanda; Ajzen, Sergio

    2014-07-01

    The present report describes a case of implant loading with an immediate temporary crown. The buccal crown surface was removed from the extracted tooth to obtain an aesthetically satisfactory result. After periodontal treatment, tooth 21 appeared proclined and showed Grade 3 mobility, indicating the need for its extraction. The remaining bone was imaged using computed tomography, and virtual surgical planning was performed using these results. The implant was immediately loaded postextraction into the fresh alveolus without a graft and flap procedure. The temporary tooth, which was manufactured using the extracted buccal surface, was a simple, fast, and low cost procedure that produced an excellent esthetic outcome. PMID:25202225

  7. Fungicide seed treatment and host resistance for the management of wheat crown rot caused by Fusarium culmorum

    Directory of Open Access Journals (Sweden)

    Shree R Pariyar

    2014-11-01

    Full Text Available Seed treatment of wheat with the fungicide thiabendazole on the development of crown rot caused by Fusarium culmorum was evaluated on six wheat genotypes with different genetic sources of resistance under controlled conditions in a growth chamber. Seed of three susceptible (S cultivars, Seri 82 (Spring bread wheat, Kiziltan 91 (Winter durum Wheat, and Demir 2000 (Winter bread wheat and three moderately resistant (MR wheat lines, 2-49 (Spring bread wheat, Altay 2000 (Winter bread wheat, and Burbot-6 (Winter bread wheat were treated with thiabendazole at concentrations of 25, 50 and 100 g ai per 100 kg seeds. Thiabendazole seed treatment caused a significant (P< 0.05 reduction in severity of crown rot on 4 out of the 6 wheat genotypes. The highest crown score reduction was recorded on S genotypes Seri 82 and Demir 2000. Thiabendazole at 100 g ai per 100 kg seed gave the highest CS reduction on both the S and MR wheat genotypes. Seed coating with thiabendazole did not show any effect on plant height, plant weight, root length and root weight. No phytotoxicity symptoms were observed at any concentration of the fungicide.

  8. Bis[(18-crown-6-κ6Osodium] (18-crown-6-1κ6O-μ-thiocyanato-1:2κ2S:N-pentathiocyanato-2κ5N-indate(IIIsodium 1,2-dichloroethane sesquisolvate

    Directory of Open Access Journals (Sweden)

    Lingqian Kong

    2009-11-01

    Full Text Available The title complex, [Na(C12H24O6]2[InNa(NCS6(C12H24O6]·1.5C2H4Cl2, has been synthesized by the reaction of 18-crown-6 with InCl3 and NaSCN. The In atom has a six-coordinate octahedral environment, being bonded to the N atoms of six thiocyanate groups. The bond lengths and angles show normal values. The crystal packing exhibits no significantly short intermolecular contacts.

  9. Influence of cervical finish line type on the marginal adaptation of zirconia ceramic crowns.

    Science.gov (United States)

    Comlekoglu, Muharrem; Dundar, Mine; Ozcan, Mutlu; Gungor, Mehmet; Gokce, Bulent; Artunc, Celal

    2009-01-01

    The current study evaluated the effect of different cervical finish line designs on the marginal adaptation of a zirconia ceramic. Four different marginal finish lines (c: chamfer, mc: mini-chamfer, fe: feather-edge and s: rounded shoulder) were prepared on phantom incisors. Die models for each preparation group (N = 28, n = 7 per finish line design group) were made of epoxy resin. Y-TZP (ICE Zirkon) frameworks were manufactured by a copy-milling system (Zirconzahn) using prefabricated blanks and tried on the master models for initial adaptation of the framework; they were then sintered, followed by veneering (Zirconzahn). The finished crowns were cemented with a polycarboxylate cement (Poly F) under 300 g load and ultrasonically cleaned. The specimens were sliced and the marginal gap was measured, considering absolute marginal opening (AMO) and marginal opening (MO) for each coping under a stereomicroscope with image processing software (Lucia). The measurements were statistically analyzed using the Kruskal Wallis, Mann Whitney and Wilcoxon Signed Ranks tests at a significance level of alpha = 0.01. Means of AMO measurement (microm) for the feather-edge finish line (87 +/- 10) was significantly lower than that of the chamfer (144 +/- 14), shoulder (114 +/- 16) and mini-chamfer finish line types (114 +/- 11) (p zirconia ceramic. Although the feather-edge finish line resulted in lower AMO and MO values, with its proven mechanical disadvantage, it cannot be recommended in clinical applications of zirconia crowns. This type of finish line has acted solely as a control group to test the null hypothesis in the current study. For better marginal adaptation, both shoulder and mini-chamfer finish line types could be suggested for zirconia crowns. PMID:19830974

  10. Internal fit of two all-ceramic systems and metal-ceramic crowns

    Directory of Open Access Journals (Sweden)

    Leandro Moura Martins

    2012-04-01

    Full Text Available OBJECTIVES: The aim of this study was to investigate the internal fit (IF of glass-infiltrated alumina (ICA - In-Ceram Alumina, yttria-stabilized tetragonal zirconia polycrystals (Y-TZP - IPS e.max ZirCAD, and metal-ceramic (MC - Ni-Cr alloy crowns. MATERIAL AND METHODS: Sixty standardized resin-tooth replicas of a maxillary first molar were produced for crown placement and divided into 3 groups (n=20 each according to the core material used (metal, ICA or Y-TZP. The IF of the crowns was measured using the replica technique, which employs a light body polyvinyl siloxane impression material to simulate the cement layer thickness. The data were analyzed according to the surfaces obtained for the occlusal space (OS, axial space (AS and total mean (TM using two-way ANOVA with Tukey ’s multiple comparison test (p<0.05. RESULTS: No differences among the different areas were detected in the MC group. For the Y-TZP and ICA groups, AS was statistically lower than both OS and TM. No differences in AS were observed among the groups. However, OS and TM showed significantly higher values for ICA and Y-TZP groups than MC group. Comparisons of ICA and Y-TZP revealed that OS was significantly lower for Y-TZP group, whereas no differences were observed for TM. CONCLUSIONS: The total mean achieved by all groups was within the range of clinical acceptability. However, the metal-ceramic group demonstrated significantly lower values than the all-ceramic groups, especially in OS.

  11. Response to Proximal Restorations Placed Either Subgingivally or Following Crown Lengthening in Patients with No History of Periodontal Disease.

    Science.gov (United States)

    Oppermann, Rui Vicente; Gomes, Sabrina Carvalho; Cavagni, Juliano; Cayana, Ezymar Gomes; Conceição, Ewerton Nocchi

    2016-01-01

    The purpose of this study was to compare the impact of resin restorations placed supragingivally or impinging periodontal biologic width (PBW). Ten patients (aged 19 to 35 years) with at least two contralateral teeth (premolars and molars) in need of proximal subgingival restorations participated. Test group (TG) (impingement of PBW with transsurgical restorations) and control croup (CG) (supragingival restorations after crown lengthening) were randomly assigned. Visible plaque (VP), bleeding on probing (BOP), periodontal probing depth (PPD), and clinical attachment loss (CAL) were evaluated at baseline and at 45, 90, and 180 days, and by transperiodontal probing at baseline and 180 days. Generalized estimating equations, Wald test, and t test were used (P ≤ .05). VP and BOP were reduced and maintained at low levels (less than 10% from day 45 on). PPD initially reduced in the TG. At day 180, no intra- or intergroup differences were observed (P > .05). CAL was higher in the CG after surgery (P crown lengthening.

  12. Significance of crown-down root canal preparation technique in endodontic therapy by using the hydroxylapatite sealer

    Directory of Open Access Journals (Sweden)

    Teodorović Nevenka

    2005-01-01

    Full Text Available Aim.To evaluate the crown-down preparation technique, and the use of hydroxylapatite based material for the definitive root canal obturation. Methods. The investigation included 20 single-canal roots with chronic periapical inflammatory lesion. Biomechanical medicamentous canal preparation was done using the double flared technique with balanced force, and the obturation was performed with hydroxylapatite sealer (unicone technique. Clinical and radiographic check-up performed 12 months after the treatment, used the following parameters: pain, swelling, percussion and palpation sensitivity, and the presence of fistula. Results. The obtained results showed a successful treatment in 18 cases, while in the 2 cases the treatment failed. Conclusion. These findings suggested that the crown-down preparation technique efficiently cleaned and shaped the root canal, and that the hydroxylapatite-based material created the homogenous and hermetic root canal obturation, so this methodology could be recommended for the endodontic therapy.

  13. PVC-Membrane Electrodes Based on 18-Crown-6 and Dibenzo-18-Crown-6 Ethers for Determination of Silver

    OpenAIRE

    ZAREH, Mohsen Mousa; AKL, Magda A.; and, Ahmd Khlil GOHNEIM

    2007-01-01

    PVC-membrane electrodes for Ag+ based on either 18-crown-6 (I) or di-benzo-18-crown-6 ether (II) were applied for the first time. The effect of solvent mediator on the electrode performance was discussed. Nernstian slope values were 59 and 58.9 mV/decade for both I and II electrode types, respectively. The linear concentration range was 10-5-10-1M. The detection limit was 7.9 \\times 10-6 M. The working pH ranges were 5-9 or 4-9, depending on the concentration of Ag+ ion. The electr...

  14. Preformed resin-veneered stainless steel crowns for restoration of primary incisors.

    Science.gov (United States)

    Croll, T P; Helpin, M L

    1996-05-01

    Stainless steel crown forms with bonded resin veneers for primary incisors are commercially available to dentists. This type of preveneered crown was developed to serve as a convenient, durable, reliable, and esthetic solution to the difficult challenge of restoring severely carious primary incisors. This article describes preveneered crowns, reviews their advantages and disadvantages, and details a technique for placement of such restorations.

  15. Field evaluation of switchgrass seedlings divergently selected for crown node placement

    NARCIS (Netherlands)

    Elbersen, H.W.; Ocumpaugh, W.R.; Hussey, M.A.; Sanderson, M.A.; Tischler, C.R.

    1999-01-01

    Excessive crown node elevation of warm-season grass seedlings is a major limitation to successful establishment. Crown node placement at or above the soil surface limits the opportunity for adventitious root development at the crown node. Switchgrass (Panicum virgatum L.) germplasm selected for low-

  16. Myofilament length dependent activation

    Energy Technology Data Exchange (ETDEWEB)

    de Tombe, Pieter P.; Mateja, Ryan D.; Tachampa, Kittipong; Mou, Younss Ait; Farman, Gerrie P.; Irving, Thomas C. (IIT); (Loyola)

    2010-05-25

    The Frank-Starling law of the heart describes the interrelationship between end-diastolic volume and cardiac ejection volume, a regulatory system that operates on a beat-to-beat basis. The main cellular mechanism that underlies this phenomenon is an increase in the responsiveness of cardiac myofilaments to activating Ca{sup 2+} ions at a longer sarcomere length, commonly referred to as myofilament length-dependent activation. This review focuses on what molecular mechanisms may underlie myofilament length dependency. Specifically, the roles of inter-filament spacing, thick and thin filament based regulation, as well as sarcomeric regulatory proteins are discussed. Although the 'Frank-Starling law of the heart' constitutes a fundamental cardiac property that has been appreciated for well over a century, it is still not known in muscle how the contractile apparatus transduces the information concerning sarcomere length to modulate ventricular pressure development.

  17. Telomere Length and Mortality

    DEFF Research Database (Denmark)

    Kimura, Masayuki; Hjelmborg, Jacob V B; Gardner, Jeffrey P;

    2008-01-01

    Leukocyte telomere length, representing the mean length of all telomeres in leukocytes, is ostensibly a bioindicator of human aging. The authors hypothesized that shorter telomeres might forecast imminent mortality in elderly people better than leukocyte telomere length. They performed mortality...... analysis in 548 same-sex Danish twins (274 pairs) aged 73-94 years, of whom 204 pairs experienced the death of one or both co-twins during 9-10 years of follow-up (1997-2007). From the terminal restriction fragment length (TRFL) distribution, the authors obtained the mean TRFL (mTRFL) and the mean values...... of the shorter 50% (mTRFL(50)) and shortest 25% (mTRFL(25)) of TRFLs in the distribution and computed the mode of TRFL (MTRFL). They analyzed the proportions of twin pairs in which the co-twin with the shorter telomeres died first. The proportions derived from the intrapair comparisons indicated that the shorter...

  18. A Characteristic Particle Length

    CERN Document Server

    Roberts, Mark D

    2015-01-01

    It is argued that there are characteristic intervals associated with any particle that can be derived without reference to the speed of light $c$. Such intervals are inferred from zeros of wavefunctions which are solutions to the Schr\\"odinger equation. The characteristic length is $\\ell=\\beta^2\\hbar^2/(8Gm^3)$, where $\\beta=3.8\\dots$; this length might lead to observational effects on objects the size of a virus.

  19. Zirconia- versus metal-based, implant-supported abutments and crowns

    DEFF Research Database (Denmark)

    Hosseini, Mandana

    was to test the reliability and validity of six aesthetic parameters used at the Copenhagen Dental School to assess the aesthetic outcome of implant-supported restorations. The aims of study III and IV were to compare the influence of different abutment and crown materials on biological, biomechanical......To restore oral functions in patients with missing teeth, single-tooth implants are a well-documented treatment option. Along with high survival rates, aesthetic factors have become an important clinical outcome variable for evaluating treatment success of implant-supported restorations. Thus...... studies have reported on aesthetic, biological, biomechanical and patient-reported outcomes of implant-supported single-tooth restorations of various biomaterials. The aim of the present thesis was to investigate the clinical performance of zirconia-based implant-supported single-tooth restorations...

  20. Zinc isotope effects in complex formation with a crown ether

    International Nuclear Information System (INIS)

    Isotope effects for zinc upon complex formation with dicyclohexano-18-crown-6 were investigated. The single stage separation factor for unit mass difference (α = 1.013) was great compared with that of calcium isotopes. One of the isotopes, 67Zn, showed a larger isotope effect than the other isotopes of even mass number. 7 refs., 1 fig

  1. SIERPIENSKI & CROWN SQUARE FRACTAL SHAPES SLOTTED MICROSTRIP PATCH ANTENNA

    Directory of Open Access Journals (Sweden)

    Dr. Yogesh Bhomia

    2014-01-01

    Full Text Available A new Sierpienski & Crown Square Fractal Shapes Slotted Microstrip Patch Antenna is proposed. A patch antenna is a narrowband, wide-beam antenna. These antennas are low profile, conformal to planar and non-planar surface, simple and inexpensive to manufacture using modern printed circuit technology, mechanically robust when mounted on rigid surface, compatible with MMIC designs and when the particular shape and mode are selected they are very versatile in terms of resonant frequency, polarization, field pattern and impedance. Microstrip patch antenna consist of a very thin metallic strip (patch placed a small fraction of a wavelength above a ground plane. The patch is generally made of conducting material such as copper or gold and can take any possible shape. This paper presents a design of Sierpienski & Crown Square Fractal Shapes Slotted Microstrip Patch Antenna and experimentally studied on IE3D software. This design is achieved by cutting Sierpienski & Crown Square Fractal Shapes Slottes in a patch. With Sierpienski & Crown Square Fractal Shapes patch antenna is designed on a FR4 substrate of thickness 1.524 mm and relative permittivity of 4.4 and mounted above the ground plane at a height of 6 mm. Bandwidth as high as 36.6% are achieved with stable pattern characteristics, such as gain and cross polarization, within its bandwidth. Impedance bandwidth, antenna gain and return loss are observed for the proposed antenna. Details of the measured and simulated results are presented and discussed.

  2. Why do crown ethers activate enzymes in organic solvents?

    NARCIS (Netherlands)

    Unen, van Dirk-Jan; Engbersen, Johan F.J.; Reinhoudt, David N.

    2002-01-01

    One of the major drawbacks of enzymes in nonaqueous solvents is that their activity is often dramatically low compared to that in water. This limitation can be largely overcome by crown ether treatment of enzymes. In this paper, we describe a number of carefully designed new experiments that have im

  3. Synthesis of new indolyl crown ethers catalyzed with ferric hydrogensulfate

    Institute of Scientific and Technical Information of China (English)

    Hossein Eshghi; Mohammad Rahimizadeh; Zahra Bakhtiarpoor; Mehdi Pordel

    2012-01-01

    Efficient reaction of bis-indolyl podand with different aldehydes using Fe(HSO4)3 as catalyst to afford the corresponding new indolyl crown ethers is described.The structures of three distinct isomers have been optimized using HyperChem geometry optimizations.Also percentage of each isomer was obtained with 1H NMR spectroscopy.

  4. Primate molar crown formation times and life history evolution revisited.

    Science.gov (United States)

    Macho, G A

    2001-12-01

    Comparative studies have convincingly demonstrated that the pattern and timing of tooth emergence are highly correlated with life-history variables and brain size. Conversely, a firm relationship between molar formation time and life-history variables has not yet been established. It seems counterintuitive that one aspect of dental development should be correlated with life-history variables, whereas the other should not. In order to shed light on this apparent discrepancy this study analyzed all data on primate molar crown formations available in the published literature in relation to life-history variables, brain size, and female body mass. Crown formation times were found to be particularly highly correlated with both female body mass and brain size. Species that depart from the overall brain/body allometry by being relatively large-bodied, e.g., Gorilla gorilla and later Theropithecus oswaldi, also have shorter molar crown formation times than expected. The reverse is not found for species that depart from the overall brain/body allometry due to their larger brains, i.e., Homo sapiens. This finding is interpreted within an evolutionary and ecological framework. Specifically, by focusing on ecological commonalities, a scenario is proposed which may allow predictions to be made about the evolutionary history of other extinct primates also. If confirmed in future studies, crown formation time may again become a powerful tool in evolutionary enquiry. PMID:11748692

  5. Classification system for conventional crown and fixed partial denture failures.

    Science.gov (United States)

    Manappallil, John Joy

    2008-04-01

    The dental literature is replete with reports on the many aspects of failure encountered with traditional fixed prosthodontic treatment, including longitudinal survival studies of crowns and fixed partial dentures and reasons for failures. However, criteria for grading or classifying the type and severity of these failures are inadequate. A classification system for conventional fixed prosthodontic failures based on severity is presented.

  6. Bio-inspired ion selective crown-ether polymer membranes

    NARCIS (Netherlands)

    Tas, Sinem

    2016-01-01

    Development of unctional membranes that are capable of selectively recognizing and transporting ions have key importance for the recovery and separation of specific icons (e.d. K+, Li+, Na+) from multicomponent mixtures. In this thesis, new membrane materials based on crown ether-metal ion host-gues

  7. Displacement of Monolithic Rubble-Mound Breakwater Crown-Walls

    DEFF Research Database (Denmark)

    Nørgaard, Jørgen Harck; Andersen, Lars Vabbersgaard; Andersen, Thomas Lykke;

    2012-01-01

    studies on caisson breakwaters, but correction terms are suggested in the present paper to obtain almost equal measured and estimated displacements. This is of great practical importance since many existing rubble-mound crown-walls are subjected to increasing wave loads due to rising sea water level from...

  8. Restoration of decayed primary incisors using strip crowns.

    Science.gov (United States)

    Pollard, M A; Curzon, J A; Fenlon, W L

    1991-05-01

    Caries of the primary incisors is a common problem that can be arrested if recognized early enough. However, the arrested decay is unsightly. Celluloid 'strip' crown forms, used with composite resin, now allow the restoration of even the most badly decayed primary incisors. The authors describe this quick and efficient technique. PMID:1884866

  9. Application of insertion-type separate inlay crown in the restoration of molar residual roots and crowns with low occlusogingival distance%插销式金瓷嵌体冠在低(牙合)龈距磨牙修复中的应用

    Institute of Scientific and Technical Information of China (English)

    陈勇; 李素贞; 李光武; 陈向琼

    2013-01-01

    Objective To estimate the clinical effect of insertion-type separate porcelain-fused-to-metal inlay crown on molar residual roots and crowns with low occlusogingival distance. Methods Thirty molar residual roots and crowns with low occlusogingival distance (<5 mm) were restored with insertion-type separate porcelain-fused-to-metal inlay crown, which is consist of the porcelain-fused-to-metal inlay crown and cast anatomy inser post. Results During the follow-up of 6~28 months, none of prostheses was loose and fractured. All the prostheses were found with good marginal fitness and well masticatory fuction without sign of gingivitis. Conclusion The insertion-type separate porcelain-fused-to-metal inlay crown is a effective method for restoring molar residual roots and crowns with low occlusogingival distance.%目的 评价插销式金瓷嵌体冠修复低(猞)龈距短冠磨牙的效果.方法 应用金瓷嵌体冠和插销桩一体的插销式金瓷嵌体冠对13例短冠磨牙进行修复.结果 经过6~28个月观察,1 3例插销式金瓷嵌体冠固位良好,均无松动脱落,边缘密合,咀嚼功能良好,无牙龈炎症.结论 插销式金瓷嵌体冠可用于短冠磨牙的修复

  10. Equilibrium CO bond lengths

    Science.gov (United States)

    Demaison, Jean; Császár, Attila G.

    2012-09-01

    Based on a sample of 38 molecules, 47 accurate equilibrium CO bond lengths have been collected and analyzed. These ultimate experimental (reEX), semiexperimental (reSE), and Born-Oppenheimer (reBO) equilibrium structures are compared to reBO estimates from two lower-level techniques of electronic structure theory, MP2(FC)/cc-pVQZ and B3LYP/6-311+G(3df,2pd). A linear relationship is found between the best equilibrium bond lengths and their MP2 or B3LYP estimates. These (and similar) linear relationships permit to estimate the CO bond length with an accuracy of 0.002 Å within the full range of 1.10-1.43 Å, corresponding to single, double, and triple CO bonds, for a large number of molecules. The variation of the CO bond length is qualitatively explained using the Atoms in Molecules method. In particular, a nice correlation is found between the CO bond length and the bond critical point density and it appears that the CO bond is at the same time covalent and ionic. Conditions which permit the computation of an accurate ab initio Born-Oppenheimer equilibrium structure are discussed. In particular, the core-core and core-valence correlation is investigated and it is shown to roughly increase with the bond length.

  11. Peri-implant biomechanical responses to standard, short-wide, and mini implants supporting single crowns under axial and off-axial loading (an in vitro study).

    Science.gov (United States)

    Kheiralla, Lamia Sayed; Younis, Jihan Farouk

    2014-02-01

    This study compared the biomechanical responses of 3 single crowns supported by 3 different implants under axial and off-axial loading. A standard implant (3.75 mm diameter, 13 mm length), a mini implant (3 mm diameter, 13 mm length), and a short-wide implant (5.7 mm diameter, 8 mm length) were embedded in epoxy resin by the aid of a surveyor to ensure their parallelism. Each implant supported a full metal crown made of Ni-Cr alloy with standardized dimensions. Strain gauges and finite element analysis (FEA) were used to measure the strain induced under axial and off-axial functional loads of 300 N. Results showed that mini implants recorded the highest microstrains, under both axial and off-axial loading. All implants showed a considerable increase in strain values under off-axial loading. Standard and short-wide implants proved to be preferable in supporting crowns, as the standard implant showed the lowest strains under axial and off-axial loading using FEA simulation, while the short-wide implant showed the lowest strains under nonaxial loading using strain gauge analysis.

  12. PEEK Primary Crowns with Cobalt-Chromium, Zirconia and Galvanic Secondary Crowns with Different Tapers—A Comparison of Retention Forces

    Directory of Open Access Journals (Sweden)

    Veronika Stock

    2016-03-01

    Full Text Available In prosthetic dentistry, double crown systems have proved their suitability as retainers for removable partial dentures. However, investigations in this context, regarding polyetheretherketone, are scarce. Therefore, the aim of this study was to test the retention force (RF between polyetheretherketone (PEEK primary and cobalt-chromium (CoCr, zirconia (ZrO2 and galvanic (GAL secondary crowns with three different tapers. Primary PEEK-crowns were milled with the tapers 0°, 1°, and 2° (n = 10/taper, respectively. Afterwards, 90 secondary crowns were fabricated: (i 30 CoCr-crowns milled from Ceramill Sintron (AmannGirrbach, Koblach, Austria (n = 10/taper, (ii 30 ZrO2-crowns milled from Ceramill ZI (AmannGirrbach, Koblach, Austria (n = 10/taper, and (iii 30 GAL-crowns made using electroforming (n = 10/taper. RF was measured in a pull-off test (20 pull-offs/specimen and data were analyzed using 2-/1-way Analysis of Variance (ANOVA followed by the Tukey-Honestly Significant Difference (HSD post hoc test and linear regression analyses (p < 0.05. The measured mean RF values ranged between 9.6 and 38.2 N. With regard to the 0°, 1°, and 2° tapered crowns, no statistically significant differences between CoCr and ZrO2 were observed (p > 0.141. At 0° taper, no differences in retention forces between GAL, CrCr, and ZrO2 crowns were found (p = 0.075. However, at 1° and 2° taper, lower RF for GAL-crowns were observed (p < 0.009, p < 0.001, respectively. According to this laboratory study, PEEK might be a suitable material for primary crowns, regardless of the taper and the material of secondary crown. Long-term results, however, are still necessary.

  13. Comparison of Primary Molar Crown Dimensions with Stainless Steel Crowns in a Sample of Iranian Children.

    Science.gov (United States)

    Afshar, Hossein; Kamali Sabeti, Arghavan; Shahrabi, Mahdi

    2015-01-01

    Background and aims. Due to anatomic variation in tooth anatomy between populations, this study compared the buccolingual (BL) and mesiodistal (MD) dimensions of primary molars with those of stainless steel crowns (SSCs) in anIranian population. Materials and methods. Impressions were taken from both dental arches of children, and casts were poured. Teeth with caries, restoration, hypoplasia or other dental anomalies were excluded. 216 primary molars were selected and divided into 4 groups of 54 each (maxillary and mandibular first and second primary molars). MD/BL dimensions were measured using a digital caliper with 0.01 mm precision on casts and SCCs (3M brand). Data were assessed using paired t-test, post hoc test and ANOVA. P < 0.05 was considered statistically significant. Results. The MD dimension of the lower first molar SSC and the BL dimension of the lower second molar SSC had the least difference with the corresponding values of the respective teeth. The MD dimension of the upper second molar SSC and the BL dimension of the upper first molar SSC had the greatest difference with the corresponding values in the respective teeth. Comparison of the two different brands of SSCs for the upper first molar revealed that both types had significant differences with the teeth in terms of both MD (P = 0.0) and BL (P = 0.0) dimensions. Conclusion. In the studied population, best adaptation was seen in second lower molars and the least adaptationswere seen in first and second upper molars.

  14. Supramolecular dimerization of crown-substituted lutetium(3) monophthalocyaninate of the host--guest type

    International Nuclear Information System (INIS)

    The reaction of tetra(15-crown-5)substituted lutetium acetate phthalocyaninate with potassium and sodium acetates in mixed CHCl3-DMSO solvent is investigated by spectrometry and PMR methods. Crown ether fragment of tetra(15-crown-5)substituted lutetium acetate phthalocyaninate was established to chelate of K+ and Na+ ions. As this takes place, the reaction of tetra(15-crown-5)substituted lutetium acetate phthalocyaninate with K+ ions may result in formation of coaxial dimers of host--guest type, whereas assuming the reaction of tetra(15-crown-5)substituted lutetium acetate phthalocyaninate with Na+ the similar dimers have no precedent

  15. Canopy Fuel Load Mapping of Mediterranean Pine Sites Based on Individual Tree-Crown Delineation

    Directory of Open Access Journals (Sweden)

    Giorgos Mallinis

    2013-12-01

    Full Text Available This study presents an individual tree-crown-based approach for canopy fuel load estimation and mapping in two Mediterranean pine stands. Based on destructive sampling, an allometric equation was developed for the estimation of crown fuel weight considering only pine crown width, a tree characteristic that can be estimated from passive imagery. Two high resolution images were used originally for discriminating Aleppo and Calabrian pines crown regions through a geographic object based image analysis approach. Subsequently, the crown region images were segmented using a watershed segmentation algorithm and crown width was extracted. The overall accuracy of the tree crown isolation expressed through a perfect match between the reference and the delineated crowns was 34.00% for the Kassandra site and 48.11% for the Thessaloniki site, while the coefficient of determination between the ground measured and the satellite extracted crown width was 0.5. Canopy fuel load values estimated in the current study presented mean values from 1.29 ± 0.6 to 1.65 ± 0.7 kg/m2 similar to other conifers worldwide. Despite the modest accuracies attained in this first study of individual tree crown fuel load mapping, the combination of the allometric equations with satellite-based extracted crown width information, can contribute to the spatially explicit mapping of canopy fuel load in Mediterranean areas. These maps can be used among others in fire behavior prediction, in fuel reduction treatments prioritization and during active fire suppression.

  16. OsCAND1 Is Required for Crown Root Emergence in Rice

    Institute of Scientific and Technical Information of China (English)

    Xiao-Fei Wang; Fen-Fang He; Xiao-Xia Ma; Chuan-Zao Mao; Charlie Hodgman; Chun-Gui Lu; Ping Wu

    2011-01-01

    Crown roots are main components of the fibrous root system and important for crops to anchor and absorb water and nutrition. To understand the molecular mechanisms of crown root formation,we isolated a rice mutant defective in crown root emergence designated as Oscand1 (named after the Arabidopsis homologous gene AtCAND1). The defect of visible crown root in the Oscand1 mutant is the result of cessation of the G2/M cell cycle transition in the crown root meristem. Map-based cloning revealed that OsCAND1 is a homolog of Arabidopsis CAND1. During crown root primordium development,the expression of OsCAND1 is confined to the root cap after the establishment of fundamental organization. The transgenic plants harboring DR5::GUS showed that auxin signaling in crown root tip is abnormal in the mutant. Exogenous auxin application can partially rescue the defect of crown root development in Oscand1. Taken together,these data show that OsCAND1 is involved in auxin signaling to maintain the G2/M cell cycle transition in crown root meristem and,consequently,the emergence of crown root. Our findings provide new information about the molecular regulation of the emergence of crown root in rice.

  17. Marginal-internal adaptation and fracture resistance of CAD/CAM crown restorations.

    Science.gov (United States)

    Yildiz, Coşkun; Vanlioğlu, Burçin Akoglu; Evren, Buket; Uludamar, Altay; Ozkan, Yasemin Kulak

    2013-01-01

    This study evaluated the marginal adaptation and fracture resistance of CAD/CAM-fabricated zirconia crowns luted using different luting agents. Twenty crown restorations were produced using IPS ZirCAD zirconium oxide blocks (IZC), and another 20 using Lava zirconium oxide blocks (L). Ten teeth were used as control. Luting agents used were an etch-and-rinse adhesive (Variolink II) and a self-etch adhesive (Multilink Automix). Internal and marginal adaptation was evaluated using silicone replica technique. Fracture resistance was evaluated using a compression test. Marginal discrepancy was 89.26 μm for L crowns and 88.84 μm for IZC crowns, and difference was statistically insignificant. However, L crowns showed significantly larger axial and occlusal gaps than IZC crowns (pCAD/CAM-fabricated crowns showed acceptable in vitro marginal discrepancies and fracture strengths. PMID:23370869

  18. Success of 6-mm Implants with Single-Tooth Restorations: A 3-year Randomized Controlled Clinical Trial.

    Science.gov (United States)

    Sahrmann, P; Naenni, N; Jung, R E; Held, U; Truninger, T; Hämmerle, C H F; Attin, T; Schmidlin, P R

    2016-06-01

    The aim of the study was to test whether implants of 6 mm in length perform equally well as 10-mm implants in terms of survival and marginal bone-level changes when supporting single crowns. Patients with a posterior single-tooth gap were randomly allocated to either the placement of a 6-mm (test) or 10-mm implant (control). The treatment protocol allowed for internal sinus lift but not for lateral bone augmentation. After a healing period of 10 wk, implants were loaded with screw-retained single crowns. Survival rates, number of pockets ≥5 mm, and bleeding-on-probing were assessed clinically. The change of marginal bone level and crown-to-implant ratios were analyzed by 2 examiners. Longitudinal intragroup analyses for marginal bone levels were performed applying the Wilcoxon signed rank test. Intergroup differences at baseline and at 3 y were compared using the Mann-Whitney U test. The effect of implant length and crown-to-implant ratio on changes of marginal bone level also was determined. Of 94 implants placed (47 test and 47 control), 78 implants (40 test and 38 control) were available for follow-up examination at 3 y of loading. One test implant was lost during the second year. Hence, implant survival was not significantly different between the 2 groups after 3 y (98% test; 100% control). We found no significant change in the crestal bone level from baseline to 3 y for test and control implants with -0.19 ± 0.62 mm and -0.33 ± 0.71 mm, respectively. The intergroup difference was not significant. Crown-to-implant ratios were not associated with a statistically significant difference in marginal bone loss. However, the number of sites with pockets ≥5 mm was significantly higher in the test group. Based on the 3-y assessment, the use of 6-mm implants can be considered a viable option when reconstructing posterior single tooth gaps (German Clinical Trials Registry: DRKS00006290). PMID:26917439

  19. Fracture resistance of computer-aided design/computer-aided manufacturing-generated composite resin-based molar crowns.

    Science.gov (United States)

    Harada, Akio; Nakamura, Keisuke; Kanno, Taro; Inagaki, Ryoichi; Örtengren, Ulf; Niwano, Yoshimi; Sasaki, Keiichi; Egusa, Hiroshi

    2015-04-01

    The aim of this study was to investigate whether different fabrication processes, such as the computer-aided design/computer-aided manufacturing (CAD/CAM) system or the manual build-up technique, affect the fracture resistance of composite resin-based crowns. Lava Ultimate (LU), Estenia C&B (EC&B), and lithium disilicate glass-ceramic IPS e.max press (EMP) were used. Four types of molar crowns were fabricated: CAD/CAM-generated composite resin-based crowns (LU crowns); manually built-up monolayer composite resin-based crowns (EC&B-monolayer crowns); manually built-up layered composite resin-based crowns (EC&B-layered crowns); and EMP crowns. Each type of crown was cemented to dies and the fracture resistance was tested. EC&B-layered crowns showed significantly lower fracture resistance compared with LU and EMP crowns, although there was no significant difference in flexural strength or fracture toughness between LU and EC&B materials. Micro-computed tomography and fractographic analysis showed that decreased strength probably resulted from internal voids in the EC&B-layered crowns introduced by the layering process. There was no significant difference in fracture resistance among LU, EC&B-monolayer, and EMP crowns. Both types of composite resin-based crowns showed fracture loads of >2000 N, which is higher than the molar bite force. Therefore, CAD/CAM-generated crowns, without internal defects, may be applied to molar regions with sufficient fracture resistance. PMID:25683749

  20. 21 CFR 872.6660 - Porcelain powder for clinical use.

    Science.gov (United States)

    2010-04-01

    ... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Miscellaneous Devices § 872.6660 Porcelain powder for clinical use... removable dentures, of jacket crowns, facings, and veneers. The device is used in prosthetic dentistry...

  1. Fracture toughness of zirconia ceramic crowns made by feather-edge tooth preparation design

    Directory of Open Access Journals (Sweden)

    Mirković Nemanja

    2012-01-01

    Full Text Available Background/Aim. Fracture toughness determines functional crown strenght and prevents damages on ceramics during mastication. There is a lack of relevant literature data about fracture toughness of crowns made by feather-edge preparation. Mechanical testing of ceramic samples is supposed to show if feather-edge tooth preparation is a successful method for making ceramic crowns without any risk of reduction of their mechanical properties. This research was done to establish effects of feather-edge tooth preparation on fracture toughness of single zirconia ceramic crowns. Methods. The research was performed as an experimental study. Sixty (60 ceramic crowns were made on non-carious extracted human premolars. Thirty (30 crowns were made on the basis of feather-edge preparation (experimental group I. The group II included 30 crowns made on 1 mm rounded shoulder. Crowns fabrication was executed on a copy mill production system “Zirkonzahn” (Zirkonzahn GMBH, Gais, Germany. The spherical compression test was used to determine fracture toughness, using 6 mm diameter ceramic ball. Fracture load for damaging ceramic crown was recorded on a universal testing machine - Zwick, type 1464, with the speed of 0.05 mm/min. Results. The results of this research introduced significant differences between fracture toughness of ceramic samples in every examined group. However, fracture toughness of crowns from both group was above 2 000 N, what was double beyond a recommended value. The mean value of fracture toughness in the feather-edge group was 2 090 N, and in shoulder group it was 2 214 N. Conclusion. This research showed a high fracture toughness of zirconia crowns made on feather-edge preparation. The examined crowns showed a fracture resistance at a sufficient distance in relation to the minimum values of functional loads. Further research of functional loads of these crown is necessary, as well as research of marginal adaptation of cemented crowns and

  2. Mappability and Read Length

    Directory of Open Access Journals (Sweden)

    Wentian eLi

    2014-11-01

    Full Text Available Power-law distributions are the main functional form forthe distribution of repeat size and repeat copy number in the human genome. When the genome is broken into fragments for sequencing, the limited size offragments and reads may prevent an unique alignment of repeatsequences to the reference sequence. Repeats in the human genome canbe as long as $10^4$ bases, or $10^5-10^6$ bases when allowing for mismatches between repeat units. Sequence reads from these regions are therefore unmappable when the read length is in the range of $10^3$ bases.With the read length of exactly 1000 bases, slightly more than 1% of theassembled genome, and slightly less than 1% of the 1kbreads, are unmappable, excluding the unassembled portion of the humangenome (8% in GRCh37. The slow decay (long tail ofthe power-law function implies a diminishing return in convertingunmappable regions/reads to become mappable with the increase of theread length, with the understanding that increasing read length willalways move towards the direction of 100% mappability.

  3. 针灸配合康复训练治疗脑卒中后半身不遂的临床研究%Clinic Analysis of Half- length - flabbiness After Hemiplegic Stroke Treated by Acupuncture Combined with Rehabilitation Training

    Institute of Scientific and Technical Information of China (English)

    黄振俊; 陈建新; 常智跃

    2011-01-01

    目的:探索针灸配合康复训练治疗脑卒中后半身不遂的有效方法.方法:将81例脑卒中后半身不遂患者随机随机分为3组,针灸治疗组27例,取头颈部和体穴治疗;康复治疗组27例,给予一对一肢体训练治疗;综合治疗组27例.结果:经过3月的治疗,针灸治疗组基本治愈3例,康复治疗组基本治愈2例,针灸配合康复治疗组基本治愈6例.结论:针灸配合康复训练治疗脑卒中后半身不遂疗效确切.%Objective:To observe and investigate the treatment of acupuncture combined with rehabilitation training for half - length -flabbiness after hemiplegic stroke clinical efficacy. Methods:60 patients with hemiplegic stroke were randomly into 3 groups,The acupuncture group,Rehebitlitation trailing group and acupuncture combined with rehabilition group;Results:During the 3months treatment, acupunture group recoverd3persons,rehabilitation grouprecoverd 2 persons,acuouncture combined rehabilition traning group recovred 6 persons;Conclusion;Acuouncture combined rehabilition traning is most effictive method to treat hemiplegic stroke.

  4. 长学制临床医学专业学生预防医学社会实践效果评价%The evaluation of preventive medicine practice effect in long-length of schooling clinical medical students

    Institute of Scientific and Technical Information of China (English)

    刘宝花; 康凤娥; 张桂芝; 岳川; 张华明; 王培玉

    2008-01-01

    To evaluate the teaching effect of preventive medicine society practice in long-length of schooling clinical medical students, the 643 students who had taken part in preventive medicine society practice were investigated with questionnaire. After society practice, we found that the students considered society practice strengthen collectivity conception and the basic opinion in preventive medicine, they would like to do health education in patients and public, they thought they got much knowledge in subject design, collecting data, writing paper and analyzing data by computer. Preventive medicine society practice can strengthen the basic opinion in preventive medicine and enhance the basic skill in scientific research for the students, which achieved the previous teaching purpose.%本文采用问卷调查方法,对本校长学制临床医学专业643名学生进行了调查,以评价其预防医学社会实践的教学效果.调查结果显示,预防医学社会实践加强了学生的群体和预防为主的观念;学生毕业后愿意向病人和人群进行健康教育;学生在课题设计、资料收集、论文撰写、计算机处理资料方面有较大收获.预防医学社会实践能够加强学生的预防医学基本观念,全面提高学生科研的基本技能,达到了预期的教学目的.

  5. Zinc isotope separation with crown ether by column chromatography

    International Nuclear Information System (INIS)

    Depleted 64Zn is a new useful material and can be widely used in the cooling water treatment in light water nuclear power plants. In the present work, column chromatographic zinc isotope separation was performed by crown ether resin which was synthesized by ourselfs, the experimental results shown that benzo-15-crown-5 resin could effectively separate the zinc isotopes. High temperature could improve the separation coefficient, while the migration distance has no effect on separation coefficient. The height equivalent to a theoretical plate increase with the increasing of the migration distance. The separation coefficients (68Zn/64Zn=6.03 x 10-4, 66Zn/64Zn=3.52 x 10-4, respectively) and the height equivalent to a theoretical plate (0.204 cm) were obtained by 20 meters chromatographic operation with the temperature of 328 K. (authors)

  6. Modeling tree crown dynamics with 3D partial differential equations.

    Science.gov (United States)

    Beyer, Robert; Letort, Véronique; Cournède, Paul-Henry

    2014-01-01

    We characterize a tree's spatial foliage distribution by the local leaf area density. Considering this spatially continuous variable allows to describe the spatiotemporal evolution of the tree crown by means of 3D partial differential equations. These offer a framework to rigorously take locally and adaptively acting effects into account, notably the growth toward light. Biomass production through photosynthesis and the allocation to foliage and wood are readily included in this model framework. The system of equations stands out due to its inherent dynamic property of self-organization and spontaneous adaptation, generating complex behavior from even only a few parameters. The density-based approach yields spatially structured tree crowns without relying on detailed geometry. We present the methodological fundamentals of such a modeling approach and discuss further prospects and applications.

  7. Gilded Silver Crown with Double-dragon Pattern

    Institute of Scientific and Technical Information of China (English)

    1996-01-01

    Unearthed from a Liao tomb at Zhangjia Yingzi, Jianping County, Liaoning Province in 1956, this gilded silver crown with double-dragon pattern is 19 cm high and 20.9 cm in diameter. Its shape is suggestive of a mountain: higher in the middle and lower on both sides. On the front is a carving in the shape of a pearl surrounded by an S-shape pattern symbolizing good fortune. There is a lively dragon on either side. The complete design is based on the old theme "two dragons play with a pearl." Traditions of the Qidan, an ancient nationality of northern China, are evident in the design of the crown. It is recorded in

  8. Fracture resistance of teeth restored with dentin-bonded crowns.

    Science.gov (United States)

    Burke, F J; Watts, D C

    1994-05-01

    While dentin-bonded crowns may hold esthetic advantages over metal-ceramic restorations, and minimal tooth preparation may also be appropriate, resistance to fracture of the restored unit is an important consideration. Dentin-bonded crowns were placed on standardized preparations in two groups of 10 maxillary premolar teeth in vitro. The preparations differed only in degree of taper. The restored specimens were subjected to compressive loading at 1 mm/min from a steel bar placed along the midline fissure. Mean fracture loads of 0.77 kN (6-degree taper) and 0.71 kN (8-degree taper) were recorded for the groups of prepared teeth, and a mean fracture load of 0.97 kN was obtained for a group of unprepared controls. Statistical analysis indicated that there was no significant difference between the fracture load of the 6-degree taper group and that of the sound control teeth.

  9. Rayleigh-Plateau instability causes the crown splash

    CERN Document Server

    Deegan, Robert D; Eggers, Jens

    2008-01-01

    The impact of a drop onto a liquid layer and the subsequent splash has important implications for diverse physical processes such as air-sea gas transfer, cooling, and combustion. In the {\\it crown splash} parameter regime, the splash pattern is highly regular. We focus on this case as a model for the mechanism that leads to secondary droplets, and thus explain the drop size distribution resulting from the splash. We show that the mean number of secondary droplets is determined by the most unstable wavelength of the Rayleigh-Plateau instability. Variations from this mean are governed by the width of the spectrum. Our results for the crown splash will provide the basis for understanding more complicated splashes.

  10. Modeling Tree Crown Dynamics with 3D Partial Differential Equations

    Directory of Open Access Journals (Sweden)

    Robert eBeyer

    2014-07-01

    Full Text Available We characterize a tree's spatial foliage distribution by the local leaf area density. Considering this spatially continuous variable allows to describe the spatiotemporal evolution of the tree crown by means of 3D partial differential equations. These offer a framework to rigorously take locally and adaptively acting effects into account, notably the growth towards light. Biomass production through photosynthesis and the allocation to foliage and wood are readily included in this model framework. The system of equations stands out due to its inherent dynamic property of self-organization and spontaneous adaptation, generating complex behavior from even only a few parameters. The density-based approach yields spatially structured tree crowns without relying on detailed geometry. We present the methodological fundamentals of such a modeling approach and discuss further prospects and applications.

  11. Dental ceramics and the molar crown testing ground

    OpenAIRE

    Thompson, P.; Dianne E. Rekow

    2004-01-01

    All ceramic crowns are highly esthetic restorations and their popularity has risen with the demand for life-like and cosmetic dentistry. Recent ceramic research has concentrated on developing a fundamental understanding of ceramic damage modes as influenced by microstructure. Dental investigations have elucidated three damage modes for ceramic layers in the 0.5-2 mm thickness using point contacts that duplicate tooth cuspal radii; classic Hertzian cone cracking, yield (pseudo-plastic behavior...

  12. Repertory Migration in the Czech Crown Lands, 1570-1630

    OpenAIRE

    Edwards, Scott Lee

    2012-01-01

    This dissertation studies the production and transmission of musical repertories in the Czech Crown Lands between 1570 and 1630. The region had long been closely linked to bordering lands, but immigration from other countries to the region escalated in the final decades of the sixteenth century with the arrival of the imperial court in Prague, particularly from Spain, Italy, and the Low Lands. The period I have chosen for study thus encompasses this time of unusually intensive travel, migrati...

  13. Aestheric effect of zirconia crown on the anterior tooth%前牙二氧化锆全瓷冠美容修复疗效的临床观察

    Institute of Scientific and Technical Information of China (English)

    毕鹏; 刘宝娟; 张红

    2012-01-01

    目的:探讨二氧化锆全瓷冠在前牙美容修复的临床综合修复效果.方法:选择64例患者的122颗前牙,二氧化锆全瓷冠修复,参照美国公共健康协会的修正标准,对临床结果进行追踪观察1年.结果:122颗二氧化锆全瓷冠在修复完成第1天6项评价指标均达到A级(100%),3个月边缘着色(96.7%)和修复体颜色(96.7%),6个月边缘着色(93.2%)和边缘密合度(98.3%),1年边缘着色(91.4%)和边缘密合度(96.6%).结论:二氧化锆全瓷冠在前牙美学修复中的临床效果较理想.%Objective To investigate the clinical results of zirconia crown on the anterior tooth. Methods All 64 patients treated with zirconia single crowns for 122 anterior teeth,r followed up and after 1 yea. Results The clinical outcome of the 122 all-ceramic zirconia crowns at a rank A in all six aspects betweenO-3months (100%),only four zirconia crowns in marginal color (96.7%) and the color of zirconia crowns (96.7%)in 3 months,eight zirconia crowns in marginal color (93.2%)and two zirconia crowns in marginal fitness (98.3% )in 6 months.ten zirconia crowns in marginal cofor (91.4%)and four zirconia crowns in marginal fitness (96.6%)in 1 year. Conclusion Porcelain-veneered zirconia single crown contribute to the aesthetic effect of the anterior teeth.

  14. Shear bond strength of self-ligating orthodontic brackets on different types of porcelain crowns

    Directory of Open Access Journals (Sweden)

    Karamdeep Singh Ahluwalia

    2013-01-01

    Full Text Available Aim: The aim of this study is to compare shear bond strength (SBS and adhesive remnant index (ARI of self-ligating orthodontic brackets bonded to different porcelain crowns. Materials and Methods: Three groups of different types of porcelain crowns, each containing 12 crowns were fabricated by the same technician and allocated to one of the study groups as follows: Group I - IPS porcelain crowns (Ivoclar Vivadent AG, Schaan, Liechtenstein, Group II - Porcelain fused to zirconia crowns (Zirkonzahn GmbH, Gais, Italy, Noritake Co., Tokyo, Japan and Group III - Conventional porcelain fused to metal crowns (Ceramco3, Densply, PA, USA. The orthodontic brackets were bonded to these crowns using hydrofluoric acid (HFA + silane etching protocol. After bonding, the SBS of the brackets were tested with a universal testing machine under standard test conditions. Results: Statistical evaluation using analysis of variance showed a significant difference between the groups (P 0.05. Chi-square comparison revealed no significant difference in ARI scores between groups (P > 0.05. Conclusions: When HFA + silane etching protocol were used, IPS crowns showed the greatest SBS of orthodontic brackets. The ARI score was non-significant. Therefore, if there is a need to place crowns over teeth then these crowns can be used for restoration of teeth before orthodontic treatment.

  15. Functional crown lengthening surgery in the aesthetic zone; periodontic and prosthodontic considerations.

    Science.gov (United States)

    Patel, Rajiv M; Baker, Paul

    2015-01-01

    Crown lengthening surgery aims to increase the amount of supragingival tooth tissue by resection of the soft and/or hard tissues to enable otherwise unrestorable teeth to be restored by increasing the retention and resistance forms of the teeth. Restoration of the worn dentition may require significant prosthodontic knowledge and skill. A prosthodontist should be involved from the beginning of the management of the patient. A number of key stages should be considered for correct management. Although the periodontist may guide the prosthodontist with regards to what may or may not be possible surgically, the overall treatment plan should be prosthodontically driven. Clinical Relevance: Toothwear of the anterior dentition provides a unique challenge to restore not only function but also to manage the aesthetic demands of the patient. To ensure that the correct outcome is reached, clinicians should be familiar with the normal anatomical proportions and relationships to enable planning and treatment to take place.

  16. Plant responses to Agrobacterium tumefaciens and crown gall development

    Directory of Open Access Journals (Sweden)

    Jochen eGohlke

    2014-04-01

    Full Text Available Agrobacterium tumefaciens causes crown gall disease on various plant species by introducing its T-DNA into the genome. Therefore, Agrobacterium has been extensively studied both as a pathogen and an important biotechnological tool. The infection process involves the transfer of T-DNA and virulence proteins into the plant cell. At that time the gene expression patterns of host plants differ depending on the Agrobacterium strain, plant species and cell-type used. Later on, integration of the T-DNA into the plant host genome, expression of the encoded oncogenes, and increase in phytohormone levels induce a fundamental reprogramming of the transformed cells. This results in their proliferation and finally formation of plant tumours. The process of reprogramming is accompanied by altered gene expression, morphology and metabolism. In addition to changes in the transcriptome and metabolome, further genome-wide (‘omic’ approaches have recently deepened our understanding of the genetic and epigenetic basis of crown gall tumour formation. This review summarizes the current knowledge about plant responses in the course of tumor development. Special emphasis is placed on the connection between epigenetic, transcriptomic, metabolomic and morphological changes in the developing tumor. These changes not only result in abnormally proliferating host cells with a heterotrophic and transport-dependent metabolism, but also cause differentiation and serve as mechanisms to balance pathogen defense and adapt to abiotic stress conditions, thereby allowing the coexistence of the crown gall and host plant.

  17. Surgical crown lengthening: a 12-month study - radiographic results

    Directory of Open Access Journals (Sweden)

    Daniela Eleutério Diniz

    2007-08-01

    Full Text Available OBJECTIVE: The purpose of this study was to perform a radiographic follow-up evaluation after a 12-month healing period, following crown lengthening surgery. MATERIAL AND METHODS: Twenty-three periodontally healthy subjects (mean age 32.5 years that required crown lengthening surgery in premolars were recruited. In a total of 30 premolars, full thickness flaps, osseous resection, and flap suturing were performed. The restorative margin was defined in the pre-surgical phase and maintained unaltered during the healing period, serving as a reference point. Standardized bitewing radiographs were taken before and after osseous reduction, and at 2, 3, 6, and 12-month healing periods. RESULTS: Intact lamina dura was observed at both mesial and distal alveolar crests only from the 3rd month. At 12-months, all alveolar crests presented lamina dura. The overall mean distance from the restorative margin to the alveolar crest achieved after osseous resection was 3.28±0.87 mm at mesial and 2.81±0.51 mm at distal sites. No significant radiographic changes in the bone crest were observed during a 12-month healing period. CONCLUSION: The findings of this study suggest that the radiographic proximal bone level observed on bitewing radiographs following crown lengthening surgery can be used as a reference to predict the future level of the healed alveolar crest.

  18. Slide crown lengthening procedure using wide surface incisions and cyanoacrylate.

    Science.gov (United States)

    Szymaitis, Dennis W

    2011-01-01

    This article introduces the slide crown lengthening procedure (SCLP), which incorporates surgical design features to overcome present crown lengthening procedure (CLP) shortcomings. The result is a 75% decrease in required surgery on adjacent teeth and a corresponding 75% reduction in surgical time. Other advantages include a reduction in surgical morbidity, improvement in terminal esthetics, and fewer teeth subject to papillae removal and apically repositioned gingiva. The 20 to 30 degree incision forming the slide is the pivotal feature; it allows effortless flap positioning. This incision angle enables wide surface incisions to adhere flaps together by producing stronger fibrin clots, decreasing tissue retraction angles, and reforming disrupted fibrin clots as incision sides slide while maintaining contact. This enhanced fibrin clot eliminates the need for sutures. The slide produced by the 20 to 30 degree incision functions for crown lengthening on all sites (facial, lingual, or palatal). This versatile surgical design introduces a new healing dimension that adapts to and provides benefits for other dental surgeries, such as gingival grafts, endodontic surgery, implants, and extractions.

  19. SURGICAL CROWN LENGTHENING: A 12-MONTH STUDY - RADIOGRAPHIC RESULTS*

    Science.gov (United States)

    Diniz, Daniela Eleutério; Okuda, Kalizia Marcela; Fonseca, Clarissa Ribeiro; Gonzalez, Marly Kimie Sonohara; Greghi, Sebastião Luiz Aguiar; do Valle, Accácio Lins; Lauris, José Roberto Pereira

    2007-01-01

    Objective The purpose of this study was to perform a radiographic follow-up evaluation after a 12-month healing period, following crown lengthening surgery. Material and methods Twenty-three periodontally healthy subjects (mean age 32.5 years) that required crown lengthening surgery in premolars were recruited. In a total of 30 premolars, full thickness flaps, osseous resection, and flap suturing were performed. The restorative margin was defined in the pre-surgical phase and maintained unaltered during the healing period, serving as a reference point. Standardized bitewing radiographs were taken before and after osseous reduction, and at 2, 3, 6, and 12-month healing periods. Results Intact lamina dura was observed at both mesial and distal alveolar crests only from the 3rd month. At 12-months, all alveolar crests presented lamina dura. The overall mean distance from the restorative margin to the alveolar crest achieved after osseous resection was 3.28±0.87 mm at mesial and 2.81±0.51 mm at distal sites. No significant radiographic changes in the bone crest were observed during a 12-month healing period. Conclusion The findings of this study suggest that the radiographic proximal bone level observed on bitewing radiographs following crown lengthening surgery can be used as a reference to predict the future level of the healed alveolar crest. PMID:19089145

  20. In vitro study of fracture strength of provisional crown materials

    Science.gov (United States)

    Sayin, Gulsum; Kara, Ozlem

    2015-01-01

    PURPOSE The purpose of this report was to evaluate the effect of the fabrication method and material type on the fracture strength of provisional crowns. MATERIALS AND METHODS A master model with one crown (maxillary left second premolar) was manufactured from Cr-Co alloy. The master model was scanned, and the data set was transferred to a CAD/CAM unit (Yenamak D50, Yenadent Ltd, Istanbul, Turkey) for the Cercon Base group. For the other groups, temporary crowns were produced by direct fabrication methods (Imident, Temdent, Structur Premium, Takilon, Systemp c&b II, and Acrytemp). The specimens were subjected to water storage at 37℃ for 24 hours, and then they were thermocycled (TC, 5000×, 5-55℃) (n=10). The maximum force at fracture (Fmax) was measured in a universal test machine at 1 mm/min. Data was analyzed by non-parametric statistics (α=.05). RESULTS Fmax values varied between 711.09-1392.1 N. In the PMMA groups, Takilon showed the lowest values (711.09 N), and Cercon Base showed the highest values (959.59 N). In the composite groups, Structur Premium showed the highest values (1392.1 N), and Acrytemp showed the lowest values (910.05 N). The composite groups showed significantly higher values than the PMMA groups (P=.01). CONCLUSION Composite-based materials showed significantly higher fracture strengths than PMMA-based materials. The CAD-CAM technique offers more advantages than the direct technique. PMID:25722834

  1. Reliability of metalloceramic and zirconia-based ceramic crowns.

    Science.gov (United States)

    Silva, N R F A; Bonfante, E A; Zavanelli, R A; Thompson, V P; Ferencz, J L; Coelho, P G

    2010-10-01

    Despite the increasing utilization of all-ceramic crown systems, their mechanical performance relative to that of metal ceramic restorations (MCR) has yet to be determined. This investigation tested the hypothesis that MCR present higher reliability over two Y-TZP all-ceramic crown systems under mouth-motion fatigue conditions. A CAD-based tooth preparation with the average dimensions of a mandibular first molar was used as a master die to fabricate all restorations. One 0.5-mm Pd-Ag and two Y-TZP system cores were veneered with 1.5 mm porcelain. Crowns were cemented onto aged (60 days in water) composite (Z100, 3M/ESPE) reproductions of the die. Mouth-motion fatigue was performed, and use level probability Weibull curves were determined. Failure modes of all systems included chipping or fracture of the porcelain veneer initiating at the indentation site. Fatigue was an acceleration factor for all-ceramic systems, but not for the MCR system. The latter presented significantly higher reliability under mouth-motion cyclic mechanical testing. PMID:20660796

  2. Study of an NC system of machining crown gears

    Science.gov (United States)

    Xu, Xiaogang; Wang, Huaqing; Yan, Jian; Gao, Shenyou

    2005-12-01

    Crown gear couplings are usually used in metallurgy and steel rolling equipments, which is manufactured by duplicating processing in common. The method makes the manipulator work hard, and the efficiency is low. The machining precision is limited to the shape of the mold and it is difficult to control the movement of machines table. This work stated an NC system to use hobbing machine. It consists of an industrial control computer, grating sensor, servo- motor and its driver source, servo driver card and other I/O equipments of inputting and outputting. The grating sensor was installed in the axial direction to trace the instantaneous position of gob rest. The radial movement of the machine table was controlled by a servomotor. When the computer captures the axial signal, this system controls the machine table by moving ahead or backwards according to the calculated value of interpolation theory. Thus, two dimensions (axial and radial) associated movement was realized while the crown gear was processed. The feature of the system is that a grating sensor used in the axial direction replaces the servomotor. By making a little change in the mechanism of the machine, NC can be implement and its redesign cost is very low. The design software has an interpolation function for a circular arc and line. The system has been used on a Y1380 gear hobbing machine, and the correlative software of machining crown gear has been designed as well. Satisfactory results have been obtained, showing facility and reliability in practical operation.

  3. Negatively charged crown ethers for binding paraquat in water

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    A water soluble negatively charged fluorescent 1,4-benzo-1,5-naphtho-36-crown-10-based host has been devised and synthesized.As shown by proton NMR,ESI mass spectrometry and UV-vis spectroscopy,it binds paraquat with a 1:1 stoichiometry and an association constant of 4.50(±0.02) ×103 M-1 in water.Its complexation with paraquat in water was further investigated by fluorescence emission spectroscopy.The results revealed that when paraquat was added to the water solution of the host,the fluorescence emission of the host was quenched by the charge transfer between the crown ether host and paraquat guest.A similar bis-p-phenylene-34-crown-10-based host was synthesized as a contrasting host.Lacking the naphthalene unit,the second host binds paraquat with a 1:1 stoichiometry and a lower association constant,1.04(±0.04) ×103 M-1,in water.This demonstrated that the naphthalene unit could not only act as a strong fluorescence group but also improve the π-πstacking interactions between the host and guest.

  4. Prosthetic and Surgical Approach for Oral Rehabilitation in a Patient with Amelogenesis Imperfecta: A Clinical Report

    Directory of Open Access Journals (Sweden)

    H. Sazegara

    2007-06-01

    Full Text Available Amelogenesis imperfecta is a heterogeneous group of hereditary disorders. Its treatment continues throughout the patients’ childhood and adolescence and consists of advanced restorative care in severe cases.A thorough prosthodontic treatment plan including orthognatic surgery, full veneer crowns and all ceramic anterior crowns is presented in this clinical report.

  5. Modeling of contact theories for the manipulation of biological micro/nanoparticles in the form of circular crowned rollers based on the atomic force microscope

    International Nuclear Information System (INIS)

    This article has dealt with the development and modeling of various contact theories for biological nanoparticles shaped as cylinders and circular crowned rollers for application in the manipulation of different biological micro/nanoparticles based on Atomic Force Microscope. First, the effective contact forces were simulated, and their impact on contact mechanics simulation was investigated. In the next step, the Hertz contact model was simulated and compared for gold and DNA nanoparticles with the three types of spherical, cylindrical, and circular crowned roller type contact geometries. Then by reducing the length of the cylindrical section in the circular crowned roller geometry, the geometry of the body was made to approach that of a sphere, and the results were compared for DNA nanoparticles. To anticipatory validate the developed theories, the results of the cylindrical and the circular crowned roller contacts were compared with the results of the existing spherical contact simulations. Following the development of these contact models for the manipulation of various biological micro/nanoparticles, the cylindrical and the circular crowned roller type contact theories were modeled based on the theories of Lundberg, Dowson, Nikpur, Heoprich, and Hertz for the manipulation of biological micro/nanoparticles. Then, for a more accurate validation, the results obtained from the simulations were compared with those obtained by the finite element method and with the experimental results available in previous articles. The previous research works on the simulation of nanomanipulation have mainly investigated the contact theories used in the manipulation of spherical micro/nanoparticles. However since in real biomanipulation situations, biological micro/nanoparticles of more complex shapes need to be displaced in biological environments, this article therefore has modeled and compared, for the first time, different contact theories for use in the biomanipulation of

  6. Quantitative comparison of mathematical models to measure surface area of canine teeth prepared to receive full veneer crowns in dogs

    Directory of Open Access Journals (Sweden)

    Caitlyn eCollins

    2015-09-01

    Full Text Available Objective: This study was performed in order to determine if mathematical modeling of the canine teeth in dogs could be utilized to provide an accurate and reliable estimation of crown surface area that could be used in both a research and clinical setting.Materials and methods: Actual surface area (aSA calculations for 32 stone dies of clinical crown preparations were acquired utilizing a tridimensional (3D laser scanner and 3D computer-aided design and manufacturing (CAD/CAM software applications. These calculations were used as a control. Seventeen unique mathematical models from 8 geometric shapes were used to calculate estimated surface area (eSA of each stone die. Linear association and agreement between eSA and aSA calculations were assessed with multiple statistical methods. Results: All methods of eSA showed a significant linear association with aSA. Five of the mathematical models [right elliptical frustum (H3, right elliptical cone (G3, right pyramidal cone (A3, right circular frustum (F2 and right circular cone (E1] were superior to the other 12 models.Conclusions: The H3 mathematical model based on the right elliptical frustum provided the most accurate estimate of crown surface area of dog teeth. However, H3 requires the use of laser scans and a 3D CAD software program. As a result, this model would be recommended for research applications. The E1 mathematical model was similar in accuracy to H3 and, given it requires only two measurements and a comparatively simple equation for calculation, this method would be recommended for clinical chair-side use.

  7. The effect of root preparation technique and instrumentation length on the development of apical root cracks.

    Science.gov (United States)

    Adorno, Carlos G; Yoshioka, Takatomo; Suda, Hideaki

    2009-03-01

    The purpose of this study was to compare the effects of root canal preparation techniques and instrumentation length on the development of apical root cracks. Forty extracted mandibular premolars with straight roots were randomly selected and mounted on resin blocks with simulated periodontal ligaments, and the apex was exposed. The teeth were divided into four groups of 10 teeth each for different canal preparation techniques and instrumentation lengths: group A: step-back preparation (SB) with stainless steel files (SF) using root canal length (RCL) to guide instrumentation length; group B: SB using RCL - 1 mm; group C: crown-down preparation (CD) with Profile using RCL; and group D: CD with PF using RCL - 1 mm. Digital images of the instrumentation sequence were compared for each tooth. Statistical analysis revealed a significant effect of instrumentation length (p 0.05) on the development of apical cracks.

  8. Ion-Pair Complexation with Dibenzo[21]Crown-7 and Dibenzo[24]Crown-8 bis-Urea Receptors.

    Science.gov (United States)

    Mäkelä, Toni; Kiesilä, Anniina; Kalenius, Elina; Rissanen, Kari

    2016-09-26

    Synthesis and ion-pair complexation properties of novel ditopic bis-urea receptors based on dibenzo[21]crown-7 (R(1) ) and dibenzo[24]crown-8 (R(2) ) scaffolds have been studied in the solid state, solution, and gas phase. In a 4:1 CDCl3 /[D6 ]DMSO solution, both receptors clearly show positive heterotropic cooperativity toward halide anions when complexed with Rb(+) or Cs(+) , with the halide affinity increasing in order I(-) studied anions compared to the corresponding cationic complexes of R(1) . Similar selectivity of the receptors toward the studied ion pairs was also observed also in the gas phase by competition experiments with mass spectrometry. A total of eight crystal structures with different rubidium and caesium halides and oxyanions were obtained in addition to the crystal structure of R(2) ⋅BaCl2 . The selectivity observed in solution and in the gas phase is explainable by the conformational differences observed in the crystal structures of ion-pair complexes with R(1) and R(2) . In the solid state, R(1) has an open conformation due to the asymmetric crown-ether scaffold, whereas R(2) has a compact, folded conformation. Computational studies of the ion-pair complexes of R(2) show that the interaction energies of the complexes increase in the order CsI

  9. A Technique to Transfer the Emergence Profile Contours of a Provisional Implant Crown to the Definitive Impression.

    Science.gov (United States)

    Shah, Karnik; Yilmaz, Burak

    2016-01-01

    This clinical report describes a method to create a proper emergence profile and accurately transfer it to the definitive impression, using an indirectly fabricated modified impression post. A provisional screwretained crown was indexed with a polyvinyl siloxane material. An autopolymerizing acrylic resin was used to modify an impression post on the polyvinyl siloxane index, which was then screwed onto the implant for the definitive impression after proper soft tissue healing. The indirectly fabricated modified impression post helped to transfer the contours to the definitive impression with minimal soft tissue irritation. PMID:27004296

  10. A Technique to Transfer the Emergence Profile Contours of a Provisional Implant Crown to the Definitive Impression.

    Science.gov (United States)

    Shah, Karnik; Yilmaz, Burak

    2016-01-01

    This clinical report describes a method to create a proper emergence profile and accurately transfer it to the definitive impression, using an indirectly fabricated modified impression post. A provisional screwretained crown was indexed with a polyvinyl siloxane material. An autopolymerizing acrylic resin was used to modify an impression post on the polyvinyl siloxane index, which was then screwed onto the implant for the definitive impression after proper soft tissue healing. The indirectly fabricated modified impression post helped to transfer the contours to the definitive impression with minimal soft tissue irritation.

  11. RICHMOND CROWN - FOR RESTORATION OF BADLY MUTILATED POSTERIOR TEETH : A CASE REPORT

    Directory of Open Access Journals (Sweden)

    Yadav

    2015-07-01

    Full Text Available Restoration of badly broken endodontically treated teeth is a common problem in restorative dentistry. Such teeth often require additional support from the root canal by means of a post and core restoration. In cases where tooth structure is significantly lost full coverage restorations for posterior teeth are necessary to achieve proper tooth form and function. Badly broken teeth with minimal or no crown structure require added retention and support. The Richmond crown can be a good treatment alternative for restoration of such teeth. The Richmond crown was introduced in 1878 and incorporated a threaded tube in the canal with a screw retained crown. It was later modified to eliminate the threaded tube and was redesigned as a one piece dowel and crown. This case report shows restoration of badly mutilated posterior teeth with Richmond crown.

  12. Crown color match of implant-supported zirconia and Porcelain-Fused-to-Metal restorations:

    DEFF Research Database (Denmark)

    Peng, Min; Fei, Wei; Hosseini, Mandana;

    2014-01-01

    Objectives: The aim of the present study was to compare the crown color match of implant supported zirconia restorations and Porcelain-Fused-to-Metal (PFM) restorations in anterior maxillary region by spectrophotometric evaluation. Materials and Methods: Eighteen patients with 29 implant......-supported single crowns in anterior maxillary area were recruited, 11 of the implant crowns were zirconia restorations and 18 were PFM restorations. Color match of the implant crown with contra-lateral/neighboring tooth at the position of body 1/3 of the crown were assessed using spectrophotometer (Spectro......ShadeTM, Micro Dental) in CIEL¿a¿b¿ coordinates. Subjective crown color match scores were evaluated. Independent sample t test of SPSS17.0 was used to compare the difference between zirconia restoration and PFM restoration. Spearman correlation was used to analyze the relationship between the spectrophotometric...

  13. Stress and Deformation Analysis of Cylinder-Crown Integrated Hydraulic Press with Large Capacity

    Institute of Scientific and Technical Information of China (English)

    Weiwei Zhang; Xiaosong Wang; Zhongren Wang

    2015-01-01

    Cylinder⁃crown integrated hydraulic press ( CCIHP ) is a new press structure. The hemispherical hydraulic cylinder also functions as a main portion of crown, which has lower weight and higher section modulus compared with the conventional hydraulic cylinder and press crown. In order to design cylinder⁃crown integrated hydraulic press with large capacity, the theoretical design of hemispherical hydraulic cylinder was first proposed, and the structural parameters of 150 MN CCIHP were listed. Then the simulation was carried out to analyze the stress and deformation of CCIHP , and weight comparison was conducted between CCIHP and conventional press. It is shown that the weight reduction for hydraulic cylinder and press crown is about 20%compared with that for conventional press, and the stress and deformation are both within the range of constraints including strength and stiffness conditions. It is possible to manufacture cylinder⁃crown integrated hydraulic press with large capacity.

  14. Analysis of Temperature Field and Thermal Crown of Roll During Hot Rolling by Simplified FEM

    Institute of Scientific and Technical Information of China (English)

    GUO Zhong-feng; LI Chang-sheng; XU Jian-zhong; LIU Xiang-hua; WANG Guo-dong

    2006-01-01

    Thermal crown of roll is an important factor, which affects strip profile. It is necessary to analyze the temperature field and thermal crown of roll for hot strip mill. A new simplified finite element method (FEM) was used to analyze the temperature field and thermal crown of roll, and corresponding models were built according to the practical boundary conditions. Transient roll temperature field and thermal crown were simulated by ANSYS FEM software with considering transient thermal contact and complex boundary condition. Temperature and thermal crown variations on roll surface nodes were obtained. The thermal crown results of roll obtained by FEM simulation were in good agreement with the measured data, indicating that simplified FEM models and results were correct.

  15. Model Building of the Initial Crown Effect Rate in 4-High Mill

    Institute of Scientific and Technical Information of China (English)

    Jianzhong XU; Dianyao GONG; Wencai ZHANG; Xianwen CHANG; Xianghua LIU; Guodong WANG

    2005-01-01

    The code for calculating the crown effect rate of hot strip steel was developed using the effect function method.The effect of the initial crown on the crown of the product in hot strip rolling was investigated. The coefficients of a polynomial of degree six for calculating the base value of initial crown effect rate in 4-high mill were determined and the compensation factors of per unit width rolling force, bending force, work roll crown and draft on the initial crown effect rate were given. The difference between the calculation result by established model and theoretical value obtained by effect function method was 4.88 μm when the strip width was 1.85 m.

  16. Forest Crown Cover Estimation in Northern Boreal and Temperate European Forest

    Science.gov (United States)

    Sirro, Laura; Hame, Tuomas; Ahola, Heikki; Lonnqvist, Anne

    2012-04-01

    A method for forest crown cover estimation using high resolution optical earth observation data was developed and tested at four study sites in Europe. Crown cover was estimated using the probability estimation method of VTT and Image2006 data. The accuracy of the crown cover predictions was assessed using reference data that were collected by visual interpretation of very high resolution aerial and space borne imagery. The average crown cover values in the reference data varied from 17 % to 86 % and in the predictions from 18 % to 80 %. The absolute root mean square error of the crown cover predictions varied between 14 % and 33 %. The results of the study showed that it is possible to map forest crown cover with twenty to thirty meter spatial resolution optical earth observation data using the single pixel values. However, understanding the variable results at different sites requires further investigation.

  17. Effect of Load Distribution on Strip Crown in Hot Strip Rolling

    Institute of Scientific and Technical Information of China (English)

    Hongshuang DI; Jianzhong XU; Dianyao GONG; Xianghua LIU; Guodong WANG; Xiaoming HE; Liying BA

    2004-01-01

    In order to establish precision model, a software to calculate the strip crown of four-high hot rolling mill was developed by using affecting function method according to the strip crown calculation theory. The effect of work roll diameter, unit width rolling load, roll bending force, work roll crown, initial strip crown and reduction, etc, on load distribution effect rate was simulated by using the software. The results show that the load distribution effect rate increases with the increase of strip width, work roll diameter, unit width rolling load, roll bending force, work roll crown, initial strip crown and reduction. Based on the simulation results, base value of load distribution effect rate and fitting coefficients of six power polynomial of load distribution effect rate modification coefficient were determined considering all of the above parameters. A simplified mathematical model for calculating load distribution effect rate was established.

  18. discouraged by queue length

    Directory of Open Access Journals (Sweden)

    P. R. Parthasarathy

    2001-01-01

    Full Text Available The transient solution is obtained analytically using continued fractions for a state-dependent birth-death queue in which potential customers are discouraged by the queue length. This queueing system is then compared with the well-known infinite server queueing system which has the same steady state solution as the model under consideration, whereas their transient solutions are different. A natural measure of speed of convergence of the mean number in the system to its stationarity is also computed.

  19. Biomechanical three-dimensional finite element analysis of monolithic zirconia crown with different cement type

    OpenAIRE

    Ha, Seung-Ryong

    2015-01-01

    PURPOSE The objective of this study was to evaluate the influence of various cement types on the stress distribution in monolithic zirconia crowns under maximum bite force using the finite element analysis. MATERIALS AND METHODS The models of the prepared #46 crown (deep chamfer margin) were scanned and solid models composed of the monolithic zirconia crown, cement layer, and prepared tooth were produced using the computer-aided design technology and were subsequently translated into 3-dimens...

  20. Comparison of crown fire modeling systems used in three fire management applications

    OpenAIRE

    Scott, J. H.

    2006-01-01

    The relative behavior of surface-crown fire spread rate modeling systems used in three fire management applications—CFIS (Crown Fire Initiation and Spread), FlamMap and NEXUS— is compared using fire environment characteristics derived from a dataset of destructively measured canopy fuel and associated stand characteristics. Although the surface-crown modeling systems predict the same basic fire behavior characteristics (type of fire, spread rate) using the same basic fire environment characte...

  1. Fracture Strength of Aged Monolithic and Bilayer Zirconia-Based Crowns

    Directory of Open Access Journals (Sweden)

    Deborah Pacheco Lameira

    2015-01-01

    Full Text Available The purpose of this study was to evaluate the effect of design and surface finishing on fracture strength of yttria-tetragonal zirconia polycrystal (Y-TZP crowns in monolithic (1.5 mm thickness and bilayer (0.8 mm zirconia coping and 0.7 mm porcelain veneer configuration after artificial aging. Bovine incisors received crown preparation and Y-TZP crowns were manufactured using CAD/CAM technique, according to the following groups (n=10: Polished monolithic zirconia crowns (PM; Glazed monolithic zirconia crowns (GM; Bi-layer crowns (BL. Crowns were cemented with resin cement, submitted to artificial aging in a chewing simulator (2.5 million cycles/80 N/artificial saliva/37°C, and tested for fracture strength. Two remaining crowns referring to PM and GM groups were submitted to a chemical composition analysis to measure the level of yttrium after aging. One-way ANOVA and Tukey’s test (P=.05 indicated that monolithic zirconia crowns presented similar fracture strength (PM=3476.2 N ± 791.7; GM=3561.5 N ± 991.6, which was higher than bilayer crowns (2060.4 N ± 810.6. There was no difference in the yttrium content among the three surfaces evaluated in the monolithic crowns. Thus, monolithic zirconia crowns present higher fracture strength than bilayer veneered zirconia after artificial aging and surface finishing does not affect their fracture strength.

  2. Aesthetic Rehabilitation of a Complicated Crown-Root Fracture of the Maxillary Incisor: Combination of Orthodontic and Implant Treatment

    Directory of Open Access Journals (Sweden)

    Érica Dorigatti de Avila

    2014-01-01

    Full Text Available The aim of this paper is to present a complex rehabilitation, of fractured tooth, with implants in anterior region considering the orthodontics extrusion to clinical success. At 7 years old, the patient fractured the maxillary left central incisor and the dentist did a crown with the fragment. Twenty years later, the patient was referred to a dental clinic for orthodontic treatment, with the chief complaint related to an accentuated deep bite, and a professional started an orthodontic treatment. After sixteen months of orthodontic treatment, tooth 21 fractured. The treatment plan included an orthodontic extrusion of tooth 21 and implant placement. This case has been followed up and the clinical and radiographic examinations show excellence esthetic results and satisfaction of patient. The forced extrusion can be a viable treatment option in the management of crown root fracture of an anterior tooth to gain bone in a vertical direction. This case emphasizes that to achieve the esthetic result a multidisciplinary approach is necessary.

  3. 18-Crown[6]ether functionalized reduced graphene oxide for membrane-free ion selective sensing

    DEFF Research Database (Denmark)

    Olsen, Gunnar; Ulstrup, Jens; Chi, Qijin

    + , with a detection limit of 10-5 M without inference from other ions (Na+ , Li+ , NH4+ and Ca2+) in concentrations up to 2.5 × 10-2 M. Similar sensing was achieved with functionalized disposable SPE electrodes. The results demonstrate that RGO-crown[6] is a conductive material full of promise for application......The focus of this work is on the synthesis of a 1-Aza-18-crown[6]ether functionalized reduced graphene oxide (RGO-crown[6]) with specific K+ binding sites on the RGO surface. Glassy carbon electrodes (GCE) functionalized with RGO-crown[6] weretested for selective potentiometric sensing of K...

  4. A tree canopy height delineation method based on Morphological Reconstruction—Open Crown Decomposition

    Science.gov (United States)

    Liu, Q.; Jing, L.; Li, Y.; Tang, Y.; Li, H.; Lin, Q.

    2016-04-01

    For the purpose of forest management, high resolution LIDAR and optical remote sensing imageries are used for treetop detection, tree crown delineation, and classification. The purpose of this study is to develop a self-adjusted dominant scales calculation method and a new crown horizontal cutting method of tree canopy height model (CHM) to detect and delineate tree crowns from LIDAR, under the hypothesis that a treetop is radiometric or altitudinal maximum and tree crowns consist of multi-scale branches. The major concept of the method is to develop an automatic selecting strategy of feature scale on CHM, and a multi-scale morphological reconstruction-open crown decomposition (MRCD) to get morphological multi-scale features of CHM by: cutting CHM from treetop to the ground; analysing and refining the dominant multiple scales with differential horizontal profiles to get treetops; segmenting LiDAR CHM using watershed a segmentation approach marked with MRCD treetops. This method has solved the problems of false detection of CHM side-surface extracted by the traditional morphological opening canopy segment (MOCS) method. The novel MRCD delineates more accurate and quantitative multi-scale features of CHM, and enables more accurate detection and segmentation of treetops and crown. Besides, the MRCD method can also be extended to high optical remote sensing tree crown extraction. In an experiment on aerial LiDAR CHM of a forest of multi-scale tree crowns, the proposed method yielded high-quality tree crown maps.

  5. Sex Identification of Red-crowned Crane by the Polymerase Chain Reaction

    Institute of Scientific and Technical Information of China (English)

    LI Jian-hong; LI Shu-ling; BAO Jun; BAI Xiu-juan

    2004-01-01

    Sex determining gene primers of Oriental White Stork were used to amplify sex-linked gene of the Red-crowned Crane's W chromosome-specific by PCR for sex identification. The sexes of 7 couples of grown Red-crowned Cranes and 15 youngs were identified. Through DNA sequence analysis, the identity is 94.77% between Red-crowned Crane and Oriental White Stork. The results of this study suggest that the application of the polymerase chain reaction technique is practicable for determining sex in the Red-crowned Crane.

  6. LINEAR POLYSILOXANE WITH DIBENZO-18-CROWN-6 MOIETIES AS LIQUID MEMBRANE CARRIER

    Institute of Scientific and Technical Information of China (English)

    GONG Shuling; LU Xueran; LU Xianming; CHEN Yuanyin

    1995-01-01

    A modified method of preparing crown functionalized linear polysiloxane has beendescribed. 4'-Allyldibenzo- 18-crown-6 was subjected to hydrosilylation withmethyldichlorosilane, followed by polycondensation with silanol-terminatedpolydimethylsiloxane to give the title crown functionalized linear polysiloxane. Thetransport properties of sodium, potassium, and ammonium salt through a bulk liquidmembrane system using the new type of crown functionalized linear polysiloxane as acarrier were investigated. It is worthy to point out that the carrier can be used repeatedlyat least six runs with no apparent change in the transport rate of potassium ion.

  7. Polyaza crown ether as non-nucleosidic building blocks in DNA-conjugates

    DEFF Research Database (Denmark)

    Jakobsen, Ulla; Rohr, Katja; Madsen, Rasmus K;

    2007-01-01

    The synthesis of amphiphilic polyaza crown ether monomers X (palmityl-substituted), Y (cholesteryl-substituted) and Z (dipalmityl-subtituted) and their incorporation into oligonucleotides are described. Their effects on thermal duplex stability were investigated by UV melting curve analysis....... Thermal denaturation experiments showed remarkable stabilization of dsDNA by polyaza crown ether monomers when incorporated in opposite positions. The series of polyaza crown ether monomers (X, Y, and Z) with different lipophilicity showed a trend of increased stability of the corresponding ds......DNA with increasing lipophilicity of the polyaza crown ether monomer....

  8. Estimation of stand crown cover using a generalized crown diameter model: application for the analysis of Portuguese cork oak stands stocking evolution

    Directory of Open Access Journals (Sweden)

    Paulo JA

    2016-06-01

    Full Text Available A generalized non-linear tree crown diameter model was developed with the aim of allowing the computation of tree crown diameter over a large range of tree dimensions, and allowing its inclusion in forest growth and yield models. The model was formulated to provide biological meaning to the predicted values. Due to the nested structure of the data analyzed (trees within stands, both mixed- and fixed-effect models were developed. Since tree crown diameter is not frequently measured in forest inventories, the validation of the mixed model was carried out by considering the population specific response. The results demonstrate that when the measurements required for the mixed model calibration are not available, the use of the fixed effect model results in less biased and more accurate estimates. The fixed model was applied to the data from the two last Portuguese National Forest Inventories (NFI to analyze the change in stand crown cover and assess the stocking evolution of cork oak stands in Portugal between 1996 and 2006. Results showed an increase in the frequency of stands with crown cover lower than 20%, as well as a decrease in the frequency of stands with crown cover between 20 and 40%. Average crown cover values were significantly different in the two NFI, with a decrease from 28.0 to 26.5% over the considered period.

  9. Digital Device in Postextraction Implantology: A Clinical Case Presentation

    Directory of Open Access Journals (Sweden)

    A. E. Borgonovo

    2014-01-01

    Full Text Available Aim. The aim of this work is to describe a case of immediate implant placement after extraction of the upper right first premolar, with the use of CAD/CAM technology, which allows an early digital impression of the implant site with an intraoral scanner (MHT 3D Progress, Verona, Italy. Case Report. A 46-year-old female was referred with a disorder caused by continuous debonding of the prosthetic crown on the upper right first premolar. Clinically, there were no signs, and the evaluation of the periapical radiograph showed a fracture of the root, with a mesial well-defined lesion of the hard tissue of the upper right first premolar, as the radiolucent area affected the root surface of the tooth. It was decided, in accordance with the patient, that the tooth would be extracted and the implant (Primer, Edierre implant system, Genoa, Italy with diameter of 4.2 mm and length of 13 mm would be inserted. After the insertion of the implant, it was screwed to the scan abutment, and a scan was taken using an intraoral scanner (MHT 3D Progress, Verona, Italy. The scanned images were processed with CAD/CAM software (Exocad DentalCAD, Darmstadt, Germany and the temporary crown was digitally drawn (Dental Knowledge, Milan, Italy and then sent to the milling machine for production with a composite monoblock. After 4 months, when the implant was osteointegrated, it was not necessary to take another dental impression, and the definitive crown could be screwed in. Conclusion. The CAD/CAM technology is especially helpful in postextraction implant for aesthetic rehabilitation, as it is possible to immediately fix a provisional crown with an anatomic shape that allows an optimal healing process of the tissues. Moreover, the removal of healing abutments, and the use of impression copings, impression materials, and dental stone became unnecessary, enabling the reduction of the chair time, component cost, and patient’s discomfort. However, it is still necessary

  10. Unicuspid and bicuspid tooth crown formation in squamates.

    Science.gov (United States)

    Handrigan, Gregory R; Richman, Joy M

    2011-12-15

    The molecular and developmental factors that regulate tooth morphogenesis in nonmammalian species, such as snakes and lizards, have received relatively little attention compared to mammals. Here we describe the development of unicuspid and bicuspid teeth in squamate species. The simple, cone-shaped tooth crown of the bearded dragon and ball python is established at cap stage and fixed in shape by the differentiation of cells and the secretion of dental matrices. Enamel production, as demonstrated by amelogenin expression, occurs relatively earlier in squamate teeth than in mouse molars. We suggest that the early differentiation in squamate unicuspid teeth at cap stage correlates with a more rudimentary tooth crown shape. The leopard gecko can form a bicuspid tooth crown despite the early onset of differentiation. Cusp formation in the gecko does not occur by the folding of the inner enamel epithelium, as in the mouse molar, but by the differential secretion of enamel. Ameloblasts forming the enamel epithelial bulge, a central swelling of cells in the inner enamel epithelium, secrete amelogenin at cap stage, but cease to do so by bell stage. Meanwhile, other ameloblasts in the inner enamel epithelium continue to secrete enamel, forming cusp tips on either side of the bulge. Bulge cells specifically express the gene Bmp2, which we suggest serves as a pro-differentiation signal for cells of the gecko enamel organ. In this regard, the enamel epithelial bulge of the gecko may be more functionally analogous to the secondary enamel knot of mammals than the primary enamel knot. PMID:21932327

  11. On the radiation stability of crown ethers in ionic liquids.

    Energy Technology Data Exchange (ETDEWEB)

    Shkrob, I.; Marin, T.; Dietz, M. (Chemical Sciences and Engineering Division); (Benedictine Univ.); (Univ. of Wisconsin at Milwaukee)

    2011-04-14

    Crown ethers (CEs) are macrocyclic ionophores used for the separation of strontium-90 from acidic nuclear waste streams. Room temperature ionic liquids (ILs) are presently being considered as replacements for traditional molecular solvents employed in such separations. It is desirable that the extraction efficacy obtained with such solvents should not deteriorate in the strong radiation fields generated by decaying radionuclides. This deterioration will depend on the extent of radiation damage to both the IL solvent and the CE solute. While radiation damage to ILs has been extensively studied, the issue of the radiation stability of crown ethers, particularly in an IL matrix, has not been adequately addressed. With this in mind, we have employed electron paramagnetic resonance (EPR) spectroscopy to study the formation of CE-related radicals in the radiolysis of selected CEs in ILs incorporating aromatic (imidazolium and pyridinium) cations. The crown ethers have been found to yield primarily hydrogen loss radicals, H atoms, and the formyl radical. In the low-dose regime, the relative yield of these radicals increases linearly with the mole fraction of the solute, suggesting negligible transfer of the excitation energy from the solvent to the solute; that is, the solvent has a 'radioprotective' effect. The damage to the CE in the loading region of practical interest is relatively low. Under such conditions, the main chemical pathway leading to decreased extraction performance is protonation of the macrocycle. At high radiation doses, sufficient to increase the acidity of the IL solvent significantly, such proton complexes compete with the solvent cations as electron traps. In this regime, the CEs will rapidly degrade as the result of H abstraction from the CE ring by the released H atoms. Thus, the radiation dose to which a CE/IL system is exposed must be maintained at a level sufficiently low to avoid this regime.

  12. Crown dimensions and proximal enamel thickness of mandibular second bicuspids

    Directory of Open Access Journals (Sweden)

    Sérgio Augusto Fernandes

    2011-08-01

    Full Text Available To achieve proper recontouring of anterior and posterior teeth, to obtain optimal morphology during enamel stripping, it is important to be aware of dental anatomy. This study aimed at evaluating crown dimensions and proximal enamel thickness in a sample of 40 extracted sound, human, mandibular, second bicuspids (20 right and 20 left. Mesiodistal, cervico-occlusal and buccolingual crown dimensions were measured using a digital caliper, accurate to 0.01 mm. Teeth were embedded in acrylic resin and cut along their long axes through the proximal surfaces to obtain 0.7 mm-thick central sections. Enamel thickness on the cut sections was measured using a perfilometer. Comparative analyses were carried out using the Student's-t test (α= 5%. The mean mesiodistal crown widths for right and left teeth were 7.79 mm (± 0.47 and 7.70 mm (± 0.51, respectively. Mean cervico-occlusal heights ranged from 8.31 mm (± 0.75 on the right to 8.38 mm (± 0.85 on the left teeth. The mean values for the buccolingual dimension were 8.67 mm (± 0.70 on the right and 8.65 mm (± 0.54 on the left teeth. The mean enamel thickness on the mesial surfaces ranged from 1.35 mm (± 0.22 to 1.40 mm (± 0.17, on the left and right sides, respectively. On the distal surfaces, the corresponding values were 1.44 mm (± 0.21 and 1.46 mm (± 0.12. No significant differences were found between measurements for right and left teeth. However, enamel thickness was significantly greater on the distal surfaces, compared with the mesial surfaces.

  13. Isotope effects of zinc in crown ether chromatography

    International Nuclear Information System (INIS)

    Isotope separation of zinc has been studied with a polymer-supported crown ether resin packed in glass columns. Chromatography was performed in a break-through manner by feeding a zinc chloride solution into the columns. The mass analysis revealed that the heavier isotope was enriched at the front part of the zinc adsorption band. This result means that the heavier isotopes are preferentially fractionated into the solution phase. The largest single-stage separation coefficient (ε) in the present work is 1.0 x 10-3 for the isotopic pair of 64Zn and 66Zn at 35degC. (author)

  14. Effect of cements on fracture resistance of monolithic zirconia crowns

    OpenAIRE

    Nakamura, Keisuke; Mouhat, Mathieu; Nergård, John Magnus; Lægreid, Solveig Jenssen; Kanno, Taro; Milleding, Percy; Örtengren, Ulf

    2016-01-01

    Abstract Objectives The present study investigated the effect of cements on fracture resistance of monolithic zirconia crowns in relation to their compressive strength. Materials and methods Four different cements were tested: zinc phosphate cement (ZPC), glass-ionomer cement (GIC), self-adhesive resin-based cement (SRC) and resin-based cement (RC). RC was used in both dual cure mode (RC-D) and chemical cure mode (RC-C). First, the compressive strength of each cement was tested according to a...

  15. FEM Calculation of Work Roll Temperature and Thermal Crown

    Institute of Scientific and Technical Information of China (English)

    KONG Xiang-wei; XU Jian-zhong; YE He-zhou; WANG Guo-dong; LIU Xiang-hua; HE Xiao-ming; BA Li-ying

    2004-01-01

    The simulation of the work roll temperature field was carried out by means of ANSYS software, and the thermal crown of the roll along its axis was obtained. The thermal-structural coupled element and contact element were introduced. In the simulation of work roll temperature field, the convert boundary condition and the transient thermal contact between the roll and strip were studied. Besides, the dynamic variation of the work roll temperature and the transient temperature distribution of the work roll during hot rolling were investigated. The calculated results were in good agreement with the measured data.

  16. Effect of sandblasting on fracture load of titanium ceramic crowns

    OpenAIRE

    Moldi, Arvind I.; Bhandari, Kishor Singh; Nagral, Sharanbassapa; Deshpandey, Sumit; Kulkarni, Pawan

    2015-01-01

    Purpose of the Study: It is difficult to achieve a reliable bond between the titanium and veneering porcelain. The aim of this study was to evaluate the bond strength between titanium ceramic crowns. Materials and Methods: The surfaces of titanium copings were divided in two groups. Group A sandblasted with 250 um (n = 10) and Group B without sandblasting (n = 10). Low-fusing porcelain was bonded over copings. A universal testing machine was used to determine the fracture load (N) of the crow...

  17. Electric field gradient and electronic properties of crown thioether compounds

    Energy Technology Data Exchange (ETDEWEB)

    Camargo Dalmatti Alves Lima, Filipe, E-mail: flima@if.usp.br; Rodrigues do Nascimento, Rafael; Brown Goncalves, Marcos [Universidade de Sao Paulo, Instituto de Fisica (Brazil); Cottenier, Stefaan [Ghent University, Center for Molecular Modeling (Belgium); Caldas, Marilia Junqueira; Petrilli, Helena Maria [Universidade de Sao Paulo, Instituto de Fisica (Brazil)

    2010-04-15

    We compare published TDPAC experiments on {sup 111}Cd in the crown thioether C{sub 6}H{sub 12}S{sub 3}AgCl with ab-initio electronic structure calculations performed within the framework of the Density Functional Theory using the Projector Augmented Wave method. We conclude from this comparison that the Cd atom at the very moment of the TDPAC experiment is positively charged, and we point out to a methodological difference between reproducing experimental electric-field gradients in molecules versus solid metals.

  18. Infrared Imagery of Crown-Fire Dynamics during FROSTFIRE.

    Science.gov (United States)

    Coen, Janice; Mahalingam, Shankar; Daily, John

    2004-09-01

    A thorough understanding of crown-fire dynamics requires a clear picture of the three-dimensional winds in and near the fire, including the flaming combustion zone and the convective updrafts produced by the fire. These observations and analyses present a unique high-spatial-resolution and high-temporal-resolution perspective of the motions within crown fires propagating up a forested 20° slope under light winds of 3 m s-1 during the FROSTFIRE experiment in interior Alaska. The purpose of this work is to calculate combustion-zone winds and examine mechanisms for the rapid propagation of crown fires. An infrared imager was used to detect high-temperature regions produced by incandescent soot particles in and near the fire and to produce a sequence of high-frequency (60 Hz), high-resolution (0.375 m × 0.8 m) two-dimensional images of temperature. An image-flow-analysis technique was applied to these data to derive wind fields in the image plane. Maximum updrafts of 32 60 m s-1 accompany maximum downdrafts of 18 30 m s-1. Horizontal wind speeds of 12 28 m s-1 show strong inflow into the base of the convective updrafts and imply recirculation of air and incomplete combustion products from the fire. Motions were more complex than a single large convective plume or many buoyant tree-scale plumes rising separately. Instead, repeated examples of narrow flaming fingers, representing a scale larger than individual trees, initially burst upslope along the ground for tens of meters at speeds up to 28 48 m s-1 before turning upward. These bursts exceeded ambient environmental winds, those considered to be driving the fire, by a factor of 10 and were low enough to propagate the crown fire actively by both igniting and preheating/ drying canopy fuel ahead of the fire. Average spread rates were 0.75 1.11 m s-1, with a peak 10-s spread rate of 1.26 m s-1. This powerful, dynamic mechanism of fire spread could explain firefighter reports of being overtaken by “fireballs.”

  19. Clinical observation of Hybrid Coat dental adhesive resin cement on postoperative hypersensitivity in vital teeth preparation for crown restoration%劲润牙本质保护膜防治牙体预备后牙本质敏感的近期疗效观察

    Institute of Scientific and Technical Information of China (English)

    牛薇

    2012-01-01

    目的 评价劲润牙本质保护膜(Hybrid coat)对活髓基牙预备后牙本质敏感的防治效果.方法 将54例(共115颗)进行固定桥修复行牙体预备的基牙,对缺牙区两侧基牙随机分组,试验组在牙体预备后表面用劲润牙本质保护膜处理,对照组牙体预备后不做任何处理,所有基牙均采用暂时冠修复,备牙后和10天试戴修复体时观察治疗效果,评定疗效,并对戴牙前评定的疗效进行统计学分析.结果 经劲润牙本质保护膜处理过的基牙牙本质敏感症状明显改善,两次疗效比价,有效率差别有统计学意义(P<0.05).结论 劲润牙本质保护膜可以有效防治活髓基牙预备后的牙本质敏感症状,值得在临床上推广应用.%Objective To evaluate the effect in preventing dentin hypersentivity by using Hybrid coat dental adhesive resin cement on prepared vital pulp abutment teeth. Methods 115 prepared vital pulp abutment teeth of 54 cases were randomly divided into experiment group and control group: One was treated with Hybrid coat dental adhesive resin cement, and the other was without any treatment as control. All of the prepared abutment teeth were protected by temporary crown or bridge. To evaluate the effect of hypersensitivity wheri try in the terminal restotations 10 days later. Then the results were analyzed using statistics software. Results After 10 days, the symptom of dentin hypersentivity by using Hybrid coat dental adhesive resin cement in experiment group was obviously alleviated. Conclusion Conclusion: Dentin hypersentivity can be effectively released by using Hybrid coat dental adhesive resin cement after tooth prepartion.

  20. [Retention of crowns as affected by film thickness of zinc phosphate cement and taper angle of crowns (author's transl)].

    Science.gov (United States)

    Otani, H; Goto, T

    1979-10-01

    Dependence of the retention of crowns at their axial wall on the film thickness of zinc phosphate cement and the taper angle was investigated. Stainless steel dies, composed of a preparation and an occlusally perforated crown the taper angle of which was 2.9, 5.7, 8.5 and 11.3 degrees respectively (Fig. 1, (a) and (b)), were cemented within three min. after the start of mix with a Shofu Micro Cement having a powder-liquid ratio of 1.5 g/0.5 cc. The thickness of the cement layer at the axial wall was regulated to a given value between 9 and 55 mu through the use of a discrepancy measurer. A Shimazu Autograph tensile test machine was employed to measure 48-hr retention (kg/cm2). The retention of the crowns was strongly dependent on the cement film thickness and the taper angle when the film thickness was below a critical value (15 mu in this experiment), but not when the film thickness was above this value (Fig. 3). This may be explained by the term of mechanical interlocking of either of the unreacted powder grains and the matrix phase in the luting cement, as schematically drawn in Fig. 6. The same findings were more evidently appeared on the semilogarythmic diagram in Fig. 4. In this diagram, the critical value was shown as intersection of two straight lines which could be drawn through all the measurements for four taper angles, using the least squares. PMID:295065

  1. Ion-Pair Complexation with Dibenzo[21]Crown-7 and Dibenzo[24]Crown-8 bis-Urea Receptors.

    Science.gov (United States)

    Mäkelä, Toni; Kiesilä, Anniina; Kalenius, Elina; Rissanen, Kari

    2016-09-26

    Synthesis and ion-pair complexation properties of novel ditopic bis-urea receptors based on dibenzo[21]crown-7 (R(1) ) and dibenzo[24]crown-8 (R(2) ) scaffolds have been studied in the solid state, solution, and gas phase. In a 4:1 CDCl3 /[D6 ]DMSO solution, both receptors clearly show positive heterotropic cooperativity toward halide anions when complexed with Rb(+) or Cs(+) , with the halide affinity increasing in order I(-) crown-ether scaffold, whereas R(2) has a compact, folded conformation. Computational studies of the ion-pair complexes of R(2) show that the interaction energies of the complexes increase in the order CsI

  2. Development of high-performance ion sensors based on the functions of crown ethers and synthetic bilayer membranes; Kurauneteru oyobi goseinibunshimaku no kino wo kiban to shita koseino ion denkyoku no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Yanagi, H.; Sakai, T.; Ogata, T. [Tokuyama Corp., Tokyo (Japan)

    1999-10-10

    High-Performance Na{sup +}, K{sup +} and Cl{sup -} ion selective electrodes (ISEs) are reported. These are based on a new concept, which is an ion recognition site formed by molecular interaction. In the case of Na and K ISEs, crown ether compounds connecting with planar substituents were used as the ionophores. The selectivities depend on the structure of substituents. It is found that the intermolecular interaction of the planar substituent plays an important role on the improvement of selectivity. The selectivities of interactive mono (crown ether) are equal to that of bis (crown ether). It means that ion recognition site like a bis (crown ether) is formed by the interaction of mono (crown ehter)s. In the case of C1 ISE, immobilized synthetic bilayer membrane with quaternary ammonium salts was used as the ion sensitive membrane. in the immobilized synthetic bilayer membrane, ordered molecular aggregates is formed. It is found that the molecular orientation improved the Cl selectivity. The insufficient selectivity over lipophilic anions can be addition of alphatic alcohol. These resulting ISEs exhibit high speed response and long life time, and they are applicable to clinical use which demands both accurate measurement and high speed processing. (author)

  3. Photoelastic Analysis of Fixed Partial Prosthesis Crown Height and Implant Length on Distribution of Stress in Two Dental Implant Systems

    OpenAIRE

    Evandro Portela Figueirêdo; Eder Alberto Sigua-Rodriguez; Marcele Jardim Pimentel; Ana Regina Oliveira Moreira; Mauro Antônio de Arruda Nóbilo; José Ricardo de Albergaria-Barbosa

    2014-01-01

    The aim of this study was to evaluate by photoelastic analysis stress distribution on short and long implants of two dental implant systems with 2-unit implant-supported fixed partial prostheses of 8 mm and 13 mm heights. Sixteen photoelastic models were divided into 4 groups: I: long implant (5 × 11 mm) (Neodent), II: long implant (5 × 11 mm) (Bicon), III: short implant (5 × 6 mm) (Neodent), and IV: short implants (5 × 6 mm) (Bicon). The models were positioned in a circular polariscope assoc...

  4. Transcript profiling of crown rootless1 mutant stem base reveals new elements associated with crown root development in rice

    Directory of Open Access Journals (Sweden)

    Van Anh Le Thi

    2011-08-01

    Full Text Available Abstract Background In rice, the major part of the post-embryonic root system is made of stem-derived roots named crown roots (CR. Among the few characterized rice mutants affected in root development, crown rootless1 mutant is unable to initiate crown root primordia. CROWN ROOTLESS1 (CRL1 is induced by auxin and encodes an AS2/LOB-domain transcription factor that acts upstream of the gene regulatory network controlling CR development. Results To identify genes involved in CR development, we compared global gene expression profile in stem bases of crl1 mutant and wild-type (WT plants. Our analysis revealed that 250 and 236 genes are down- and up-regulated respectively in the crl1 mutant. Auxin induces CRL1 expression and consequently it is expected that auxin also alters the expression of genes that are early regulated by CRL1. To identify genes under the early control of CRL1, we monitored the expression kinetics of a selected subset of genes, mainly chosen among those exhibiting differential expression, in crl1 and WT following exogenous auxin treatment. This analysis revealed that most of these genes, mainly related to hormone, water and nutrient, development and homeostasis, were likely not regulated directly by CRL1. We hypothesized that the differential expression for these genes observed in the crl1 mutant is likely a consequence of the absence of CR formation. Otherwise, three CRL1-dependent auxin-responsive genes: FSM (FLATENNED SHOOT MERISTEM/FAS1 (FASCIATA1, GTE4 (GENERAL TRANSCRIPTION FACTOR GROUP E4 and MAP (MICROTUBULE-ASSOCIATED PROTEIN were identified. FSM/FAS1 and GTE4 are known in rice and Arabidopsis to be involved in the maintenance of root meristem through chromatin remodelling and cell cycle regulation respectively. Conclusion Our data showed that the differential regulation of most genes in crl1 versus WT may be an indirect consequence of CRL1 inactivation resulting from the absence of CR in the crl1 mutant. Nevertheless

  5. Alkali-crown ether complexes at metal surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Thontasen, Nicha; Deng, Zhitao; Rauschenbach, Stephan [Max Planck Institute for Solid State Research, Stuttgart (Germany); Levita, Giacomo [University of Trieste, Trieste (Italy); Malinowski, Nikola [Max Planck Institute for Solid State Research, Stuttgart (Germany); Bulgarian Academy of Sciences, Sofia (Bulgaria); Kern, Klaus [Max Planck Institute for Solid State Research, Stuttgart (Germany); EPFL, Lausanne (Switzerland)

    2010-07-01

    Crown ethers are polycyclic ethers which, in solution, selectively bind cations depending on the size of the ring cavity. The study of a single host-guest complex is highly desirable in order to reveal the characteristics of these specific interactions at the atomic scale. Such detailed investigation is possible at the surface where high resolution imaging tools like scanning tunneling microscopy (STM) can be applied. Here, electrospray ion beam deposition (ES-IBD) is employed for the deposition of Dibenzo-24-crown-8 (DB24C8)-H{sup +}, -Na{sup +} and -Cs{sup +} complexes on a solid surface in ultrahigh vacuum (UHV). Where other deposition techniques have not been successful, this deposition technique combines the advantages of solution based preparation of the complex ions with a highly clean and controlled deposition in UHV. Single molecular structures and the cation-binding of DB24C8 at the surface are studied in situ by STM and MALDI-MS (matrix assisted laser desorption ionization mass spectrometry). The internal structure of the complex, i.e. ring and cavity, is observable only when alkali cations are incorporated. The BD24C8-H{sup +} complex in contrast appears as a compact feature. This result is in good agreement with theoretical models based on density functional theory calculations.

  6. Metabolic changes in Avena sativa crowns recovering from freezing.

    Directory of Open Access Journals (Sweden)

    Cynthia A Henson

    Full Text Available Extensive research has been conducted on cold acclimation and freezing tolerance of fall-sown cereal plants due to their economic importance; however, little has been reported on the biochemical changes occurring over time after the freezing conditions are replaced by conditions favorable for recovery and growth such as would occur during spring. In this study, GC-MS was used to detect metabolic changes in the overwintering crown tissue of oat (Avena sativa L. during a fourteen day time-course after freezing. Metabolomic analysis revealed increases in most amino acids, particularly proline, 5-oxoproline and arginine, which increased greatly in crowns that were frozen compared to controls and correlated very significantly with days after freezing. In contrast, sugar and sugar related metabolites were little changed by freezing, except sucrose and fructose which decreased dramatically. In frozen tissue all TCA cycle metabolites, especially citrate and malate, decreased in relation to unfrozen tissue. Alterations in some amino acid pools after freezing were similar to those observed in cold acclimation whereas most changes in sugar pools after freezing were not. These similarities and differences suggest that there are common as well as unique genetic mechanisms between these two environmental conditions that are crucial to the winter survival of plants.

  7. Purification and characterization of a pineapple crown leaf thiol protease.

    Science.gov (United States)

    Singh, L Rupachandra; Devi, Th Premila; Devi, S Kunjeshwori

    2004-02-01

    A thiol protease was isolated and purified from the crown leaf of pineapple, Ananas comosus (L.) Merr. cv. Queen, by an immunoaffinity procedure. After the purification to electrophoretic homogeneity, the enzyme was characterized with respect to some of its physico-chemical and kinetic properties. The molecular weight of the protease (22.4-22.9 kDa), Km (97 microM) and kcat (8.8 s(-1)) for its esterolytic cleavage of the synthetic protease substrate N(alpha)-CBZ-L-lysine p-nitrophenyl ester, the concentration of its thiol activator L-cysteine required for half maximal activation A0.5 (9.9 microM), optimum pH (6.5) for its proteolytic action on azocasein, T(1/2) (60 degrees C) for inactivation by heating the enzyme (35.5 microg protein/mL) in citrate buffer pH 6.0 for 15 min, and SH-group content (0.98 mol/mol enzyme) were determined. Most of these physicochemical and kinetic properties were found to be similar to those of the already well-characterized stem bromelain (EC 3.4.22.32). Thus, the immunoaffinity purified crown leaf protease appeared to be closely related to stem bromelain.

  8. Research on work roll thermal crown in cold rolling mill

    Science.gov (United States)

    Song, Lei; Shen, Mingang; Chen, Xuebo; Wang, Junsheng

    2013-05-01

    The factors which have influence on the work roll thermal crown in cold strip rolling are discussed. The heat transferring in three directions (radial axis and circumference) were considered for calculating the work roll thermal deformation. Therefore, it is a three dimensions unstable system for the work roll temperature calculation. The plastic deformation work and friction heat are calculated by the divided element and digital integration method. The simplified calculation model is built for the heat transferring along work roll. There are four zones for work roll heat transferring: roll gap zone air cooling zone emulsion zone rolls contact zone. The heat transferring between the zones is decided by the temperature difference. The inter temperature field and thermal deformation of work roll can be calculated by two-dimension finite difference method. The work roll temperature and thermal crown of actual application cold rolling mill are analyzed by the model. By the comparison between calculated values and measured values, the work roll thermal calculation model can meet the accuracy requirement of on-line control.

  9. Metabolic changes in Avena sativa crowns recovering from freezing.

    Science.gov (United States)

    Henson, Cynthia A; Duke, Stanley H; Livingston, David P

    2014-01-01

    Extensive research has been conducted on cold acclimation and freezing tolerance of fall-sown cereal plants due to their economic importance; however, little has been reported on the biochemical changes occurring over time after the freezing conditions are replaced by conditions favorable for recovery and growth such as would occur during spring. In this study, GC-MS was used to detect metabolic changes in the overwintering crown tissue of oat (Avena sativa L.) during a fourteen day time-course after freezing. Metabolomic analysis revealed increases in most amino acids, particularly proline, 5-oxoproline and arginine, which increased greatly in crowns that were frozen compared to controls and correlated very significantly with days after freezing. In contrast, sugar and sugar related metabolites were little changed by freezing, except sucrose and fructose which decreased dramatically. In frozen tissue all TCA cycle metabolites, especially citrate and malate, decreased in relation to unfrozen tissue. Alterations in some amino acid pools after freezing were similar to those observed in cold acclimation whereas most changes in sugar pools after freezing were not. These similarities and differences suggest that there are common as well as unique genetic mechanisms between these two environmental conditions that are crucial to the winter survival of plants.

  10. Genetic variation between Phytophthora cactorum isolates differing in their ability to cause crown rot in strawberry

    NARCIS (Netherlands)

    Eikemo, H.; Klemsdal, S.S.; Riisberg, I.; Bonants, P.J.M.; Stensvand, A.; Tronsmo, A.M.

    2004-01-01

    Analysis of 44 isolates of Phytophthora cactorum, isolated from strawberry and other hosts, by AFLP showed that the crown rot pathotype is different from leather rot isolates and from P. cactorum isolated from other hosts. 16 of 23 crown rot isolates, including isolates from Europe, Japan, Australia

  11. Dynamic spatial patterns of leaf traits affect total respiration on the crown scale

    Science.gov (United States)

    Wang, Xiaolin; Zhou, Hongxuan; Han, Fengsen; Li, Yuanzheng; Hu, Dan

    2016-05-01

    Temporal and spatial variations of leaf traits caused conflicting conclusions and great estimating errors of total carbon budget on crown scales. However, there is no effective method to quantitatively describe and study heterogeneous patterns of crowns yet. In this study, dynamic spatial patterns of typical ecological factors on crown scales were investigated during two sky conditions, and CEZs (crown ecological zones) method was developed for spatial crown zoning, within which leaf traits were statistically unchanged. The influencing factors on hourly and spatial variations of leaf dark respiration (Rd) were analysed, and total crown respiration (Rt) was estimated based on patterns of CEZs. The results showed that dynamic spatial patterns of air temperature and light intensity changed significantly by CEZs in special periods and positions, but not continuously. The contributions of influencing factors on variations of Rd changed with crown depth and sky conditions, and total contributions of leaf structural and chemical traits were higher during sunny days than ecological factors, but lower during cloudy days. The estimated errors of Rt may be obviously reduced with CEZs. These results provided some references for scaling from leaves to crown, and technical foundations for expanding lab-control experiments to open field ones.

  12. A Reliability Generalization Study of the Marlowe-Crowne Social Desirability Scale.

    Science.gov (United States)

    Beretvas, S, Natasha; Meyers, Jason L.; Leite, Walter L.

    2002-01-01

    Conducted a reliability generalization study of the Marlowe-Crowne Social Desirability Scale (D. Crowne and D. Marlowe, 1960). Analysis of 93 studies show that the predicted score reliability for male adolescents was 0.53, and reliability for men's responses was lower than for women's. Discusses the need for further analysis of the scale. (SLD)

  13. Rapid crown root development confers tolerance to zinc deficiency in rice

    Directory of Open Access Journals (Sweden)

    Amrit Kaur eNanda

    2016-03-01

    Full Text Available Zinc (Zn deficiency is one of the leading nutrient disorders in rice (Oryza sativa. Many studies have identified Zn efficient rice genotypes, but causal mechanisms for Zn deficiency tolerance remain poorly understood. Here we report a detailed study of the impact of Zn deficiency on crown root development of rice genotypes, differing in their tolerance to this stress. Zn deficiency delayed crown root development and plant biomass accumulation in both Zn efficient and inefficient genotypes, with the effects being much stronger in the latter. Zn efficient genotypes had developed new crown roots as early as three days after transplanting (DAT to a Zn deficient field and that was followed by a significant increase in total biomass by 7 DAT. Zn-inefficient genotypes developed few new crown roots and did not increase biomass during the first seven days following transplanting. This correlated with Zn efficient genotypes retranslocating a higher proportion of shoot Zn to their roots, compared to Zn inefficient genotypes. These latter genotypes were furthermore not efficient in utilizing the limited Zn for root development. Histological analyses indicated no anomalies in crown tissue of Zn-efficient or inefficient genotypes that would have suggested crown root emergence was impeded. We therefore conclude that the rate of crown root initiation was differentially affected by Zn deficiency between genotypes. Rapid crown root development, following transplanting, was identified as a main causative trait for tolerance to Zn deficiency and better Zn retranslocation from shoot to root was a key attribute of Zn-efficient genotypes.

  14. Tree crown delineation from high resolution airborne LiDAR based on densities of high points

    NARCIS (Netherlands)

    Rahman, M.Z.A.; Gorte, B.G.H.

    2009-01-01

    Tree detection and tree crown delineation from Airborne LiDAR has been focusing mostly on utilizing the canopy height model (CHM). This paper presents a method for individual tree crown delineation based on densities of high points (DHP) from the high resolution Airborne LiDAR. The DHP method relies

  15. Large acceleration of α-chymotrypsin-catalyzed dipeptide formation by 18-crown-6 in organic solvents

    NARCIS (Netherlands)

    Unen, van Dirk-Jan; Engbersen, Johan F.J.; Reinhoudt, David N.

    1998-01-01

    The effects of 18-crown-6 on the synthesis of peptides catalyzed by α-chymotrypsin are reported. Lyophilization of the enzyme in the presence of 50 equivalents of 18-crown-6 results in a 425-fold enhanced activity when the reaction between the 2-chloroethylester of N-acetyl-L-phenylalanine and L-phe

  16. Investigating assumptions of crown archetypes for modelling LiDAR returns

    NARCIS (Netherlands)

    Calders, K.; Lewis, P.; Disney, M.; Verbesselt, J.; Herold, M.

    2013-01-01

    LiDAR has the potential to derive canopy structural information such as tree height and leaf area index (LAI), via models of the LiDAR signal. Such models often make assumptions regarding crown shape to simplify parameter retrieval and crown archetypes are typically assumed to contain a turbid mediu

  17. Retention force of differently fabricated telescopic PEEK crowns with different tapers.

    Science.gov (United States)

    Stock, Veronika; Wagner, Christina; Merk, Susanne; Roos, Malgorzata; Schmidlin, Patrick R; Eichberger, Marlis; Stawarczyk, Bogna

    2016-01-01

    To assess the retention force between primary and secondary PEEK crowns made by different fabrication methods. Primary crowns with different tapers (0°, 1°, and 2°) were fabricated and secondary crowns that were either milled from breCam BioHPP blanks, pressed from pellets (BioHPP Pellet) or granules (BioHPP Granulat) were produced. Each specimen was measured 20 times in a pulloff-test and results were analyzed using 2-/1-way ANOVA and linear regression analyses (ptapered crowns milled secondary crowns showed lower retention forces compared to pressed pellet crowns. Crowns with a 1° taper, however, showed no impact of the fabrication method on retention force. At a 2° taper, granular pressed crowns displayed lower values than their milled counterparts. Within the milled group, a 0° taper showed lower retention values than the higher tapers, whereas in the pressed groups, no impact of taper angle on retention force was found. PMID:27477224

  18. Evaluation of the occlusal contact of crowns fabricated with the bite impression method.

    Science.gov (United States)

    Makino, Sachi; Okada, Daizo; Shin, Chiharu; Ogura, Reiko; Ikeda, Masaomi; Miura, Hiroyuki

    2013-09-30

    In prosthodontic treatment, reconstruction of a proper occlusal contact relationship is very important as well as reconstruction of a proper interproximal relationship and marginal fitness. Unfortunately, occlusal relationships are sometimes lost in the process of occlusal adjustment of crowns. The purpose of this study was to compare the occlusal contacts of single crown fabricated by two different types of impression techniques. Nine subjects, whose molars required treatment with crown restoration, were enrolled in this study. Full cast crowns were fabricated using two types of impression techniques: the conventional impression method (CIM) and the bite impression method (BIM). The occlusal contacts of crowns were precisely evaluated at the following stages: after occlusal adjustment on the articulator (Step 0), before occlusal adjustment in the mouth (Step 1), after occlusal adjustment at the intercuspal position (Step 2), and after occlusal adjustment during lateral and protrusive excursions (Step 3). The number of occlusal contacts of the crowns on the functional cusps fabricated with BIM was significantly greater than that with CIM after occlusal adjustment. For this reason, the crowns fabricated with BIM might have a more functionally desirable occlusal surface compared to the crowns fabricated with CIM.

  19. 氧化锆全瓷与金属烤瓷冠修复牙体缺损:8个月后牙周状况随访%Zirconia all-ceramic crown and porcelain fused to metal crown for dental defects: an 8-month follow-up of periodontal conditions

    Institute of Scientific and Technical Information of China (English)

    胡芳

    2015-01-01

    BACKGROUND:Zirconia al-ceramic crown restoration has good biocompatibility and corrosion resistance, and has little irritation to the human periodontal tissue. OBJECTIVE:To compare the clinical curative effects of zirconia al-ceramic and porcelain fused to metal crowns in the repair of dental defects. METHODS: Twenty patients (120 teeth) scheduled for crown lengthening+crown repair were enroled, including 7 males and 13 females, aged 19-60 years, and then randomly divided into observation group and control group. In the observation group, zirconia al-ceramic crown was used; and in the control group, porcelain fused to metal crown was used. Periodontal conditions, coordination of gingival margin height, and crown edge concealment were compared between the two groups at 8 months after restoration. RESULTS AND CONCLUSION: At 8 months after restoration, the observation group had better periodontal conditions and crown edge concealment than the control group (P < 0.05), and the time of wearing a temporary crown and recovery time were also shorter in the observation group than the control group (P < 0.05). There was no significant difference in the gingival margin height between the two groups at 1, 3 and 8 months after restoration. These findings indicate that after crown lengthening, the zirconia al-ceramic restoration for dental defect repair has better therapeutic effects than the porcelain fused to metal restoration, which can have better marginal adaptation, improve crown edge concealment, reduce gingivitis, decrease plaque adhesion ability, and preferably maintain the periodontal health.%背景:氧化锆全瓷冠修复体具有良好的生物相容性及耐腐蚀性,并且对人体牙周组织刺激较小.目的:对比氧化锆全瓷和金属烤瓷冠两种材料修复牙体缺损的临床疗效.方法:纳入20例(120颗牙)拟行牙冠延长联合牙冠修复患者,其中男7例,女13例,年龄19-60岁,采用随机数字表法均分为观察组和对照组,观

  20. A delayed hypersensitivity reaction to a stainless steel crown: a case report.

    Science.gov (United States)

    Yilmaz, A; Ozdemir, C E; Yilmaz, Y

    2012-01-01

    Stainless steel crowns are commonly used to restore primary or permanent teeth in pediatric restorative dentistry. Here, we describe a case of a delayed hypersensitivity reaction, which manifested itself as perioral skin eruptions, after restoring the decayed first permanent molar tooth of a 13-year-old Caucasian girl with a preformed stainless steel crown. The eruptions completely healed within one week after removal of the stainless steel crown. The decayed tooth was then restored with a bis-acryl crown and bridge. Since no perioral skin eruptions occurred during the six-month follow-up, we presume that the cause of the perioral skin eruptions was a delayed hypersensitivity reaction, which was triggered by the nickel in the stainless steel crown.

  1. QTL analysis of crown rust resistance in perennial ryegrass under conditions of natural and artificial infection

    DEFF Research Database (Denmark)

    Schejbel, Britt; Jensen, Louise Friis Bach; Xing, Yongzhong;

    2007-01-01

    Crown rust is an economically devastating disease of perennial ryegrass. Both artificial crown rust inoculations, with the possibility of several selection cycles in one year, as well as marker-assisted selection can be used for more efficient breeding of new resistant cultivars. The objective...... of this study was to map quantitative trait loci (QTL) for response to crown rust infection in perennial ryegrass. In order to identify relevant markers for response to crown rust infection, QTL mapping was performed on a ryegrass mapping population which was evaluated for resistance in the field for two years...... as well as by artificial pathogen inoculations using a detached leaf assessment. The broad sense heritability values for the field, detached leaf and combined assays were 0.42, 0.56, and 0.64, respectively, indicating a good potential for selection for crown rust resistance. A total of six QTLs were...

  2. Sorbents based on crown ethers: preparation and application for the sorption of strontium

    Science.gov (United States)

    Bezhin, N. A.; Dovhyi, I. I.

    2015-12-01

    The key approaches to the synthesis of crown ether-based sorbents, including immobilization both with and without covalent bonding, are reviewed. Examples of sorbent preparation using anodic oxidation, chemical modification of polymers, polycondensation reactions, chemical modification of inorganic supports and radiochemical synthesis for covalent bonding of crown ether moieties are considered. Immobilization methods without covalent bonding including support synthesis in the presence of crown ethers, impregnation of supports with a crown ether solution and the use of powdered crown ether as a sorbent are presented. The applications of sorbents for selective removal of strontium from solutions of radioactive waste and spent nuclear fuel, for radiochemical analysis (determination of strontium in water, soil and biological materials) and for separation of strontium and yttrium isotopes are discussed. The bibliography includes 114 references.

  3. Visualization of the trimeric P2X2 receptor with a crown-capped extracellular domain.

    Science.gov (United States)

    Mio, Kazuhiro; Kubo, Yoshihiro; Ogura, Toshihiko; Yamamoto, Tomomi; Sato, Chikara

    2005-11-25

    The P2X2 purinergic receptor permeates cationic ions in response to stimulation by ATP and mediates fast synaptic transmission. Here, we purified the P2X2 receptor using baculovirus-Sf9 cell expression system and observed its structure using electron microscopy. The FLAG-tagged P2X2 receptor, which has intact ion channel function, was purified to be a single peak by affinity purification and gel filtration chromatography. It was confirmed to be a trimer by introducing cross-linking. Negatively stained P2X2 protein images were homogeneous and picked up by automated pick-up programs, aligned, and classified using the modified growing neural gas network method. Similarly oriented projections were averaged to decrease the signal-to-noise ratio. These images demonstrate an inverted three-sided pyramid with the dimensions of 215 A in height and 200 A in side length. It is composed of a high-density trunk and a stain-permeable swollen extracellular domain of a crown-shaped structure. The internal cavities and constituent segments were clearly demonstrated in both the raw images and the averaged images. The threefold symmetrical top view demonstrates the first visual evidence of the trimeric composition of the P2X receptor family. PMID:16219297

  4. [An automatic extraction algorithm for individual tree crown projection area and volume based on 3D point cloud data].

    Science.gov (United States)

    Xu, Wei-Heng; Feng, Zhong-Ke; Su, Zhi-Fang; Xu, Hui; Jiao, You-Quan; Deng, Ou

    2014-02-01

    Tree crown projection area and crown volume are the important parameters for the estimation of biomass, tridimensional green biomass and other forestry science applications. Using conventional measurements of tree crown projection area and crown volume will produce a large area of errors in the view of practical situations referring to complicated tree crown structures or different morphological characteristics. However, it is difficult to measure and validate their accuracy through conventional measurement methods. In view of practical problems which include complicated tree crown structure, different morphological characteristics, so as to implement the objective that tree crown projection and crown volume can be extracted by computer program automatically. This paper proposes an automatic untouched measurement based on terrestrial three-dimensional laser scanner named FARO Photon120 using plane scattered data point convex hull algorithm and slice segmentation and accumulation algorithm to calculate the tree crown projection area. It is exploited on VC+6.0 and Matlab7.0. The experiments are exploited on 22 common tree species of Beijing, China. The results show that the correlation coefficient of the crown projection between Av calculated by new method and conventional method A4 reaches 0.964 (ppoint or sixteen-point projection with fixed angles to estimate crown projections, and (2) different regular volume formula to simulate crown volume according to the tree crown shapes. Based on the high-resolution 3D LIDAR point cloud data of individual tree, tree crown structure was reconstructed at a high rate of speed with high accuracy, and crown projection and volume of individual tree were extracted by this automatical untouched method, which can provide a reference for tree crown structure studies and be worth to popularize in the field of precision forestry.

  5. A comparison of crown attributes for six genotypes on Pinus taeda as affected by site and management intensity

    OpenAIRE

    Carbaugh, Eric Douglas

    2015-01-01

    This study was designed to investigate the development of the crown architecture of six genotypes of loblolly pine across a variety of growing conditions, and also to investigate the stability of the crown ideotype for these genotypes over a range of site and silvicultural management regimes. The objectives were to determine whether the crown dimensions that determine the crown ideotype of four clones, a mass-control-pollinated family, and an open-pollinated family of Pinus taeda L. are cons...

  6. Restoration of Anterior Dental Erosion with a Combination of Veneers and Crowns: A 3-Year Case Report.

    Science.gov (United States)

    Abreu, Amara; Rucker, M Bryan; Loza, María A; Brackett, William W

    2015-12-01

    This report describes the conservative management of a 40-year-old female patient with smooth, eroded facial enamel affecting her maxillary anterior and some posterior teeth. Using conventional enamel bonding, pressed leucite-reinforced laminate veneers were used to restore the length, contour, and esthetics of the maxillary right canine, as well as of the right lateral and both central incisors; at the same time, it was necessary to restore the maxillary left lateral incisor, canine, and first premolar of the same quadrant with all-ceramic crowns of the same material. The patient has been followed for 3 years and demonstrates a good esthetic outcome with no shade discrepancy between the two types of restoration. Apparently, the tooth structure, though eroded, was able to provide an adequate bonding substrate for these adhesive restorations. PMID:26602583

  7. Use of modified lip repositioning technique associated with esthetic crown lengthening for treatment of excessive gingival display: A case report of multiple etiologies

    Directory of Open Access Journals (Sweden)

    Matheus Bortoluzzi Mantovani

    2016-01-01

    Full Text Available Excessive gingival display during smile can result in compromised esthetics. This study aims to report a case of excessive gingival display with multiple etiologies treated by means of modified lip repositioning technique associated with esthetic crown lengthening. A 23-year-old female patient, with 5-mm gingival display during smile caused by altered passive eruption and hypermobility of the upper lip, underwent the modified lip repositioning technique associated with gingivectomy followed by flap elevation and ostectomy/osteoplasty. Seven months after the second procedure, the patient had her esthetic complaint solved appearing stable in the observation period. The modified lip repositioning technique is an effective procedure employed to reduce gingival display and when associated with esthetic clinical crown lengthening, can appropriately treat cases of gummy smile.

  8. Use of modified lip repositioning technique associated with esthetic crown lengthening for treatment of excessive gingival display: A case report of multiple etiologies.

    Science.gov (United States)

    Mantovani, Matheus Bortoluzzi; Souza, Eduardo Clemente; Marson, Fabiano Carlos; Corrêa, Giovani Oliveira; Progiante, Patrícia Saram; Silva, Cléverson Oliveira

    2016-01-01

    Excessive gingival display during smile can result in compromised esthetics. This study aims to report a case of excessive gingival display with multiple etiologies treated by means of modified lip repositioning technique associated with esthetic crown lengthening. A 23-year-old female patient, with 5-mm gingival display during smile caused by altered passive eruption and hypermobility of the upper lip, underwent the modified lip repositioning technique associated with gingivectomy followed by flap elevation and ostectomy/osteoplasty. Seven months after the second procedure, the patient had her esthetic complaint solved appearing stable in the observation period. The modified lip repositioning technique is an effective procedure employed to reduce gingival display and when associated with esthetic clinical crown lengthening, can appropriately treat cases of gummy smile.

  9. Use of modified lip repositioning technique associated with esthetic crown lengthening for treatment of excessive gingival display: A case report of multiple etiologies.

    Science.gov (United States)

    Mantovani, Matheus Bortoluzzi; Souza, Eduardo Clemente; Marson, Fabiano Carlos; Corrêa, Giovani Oliveira; Progiante, Patrícia Saram; Silva, Cléverson Oliveira

    2016-01-01

    Excessive gingival display during smile can result in compromised esthetics. This study aims to report a case of excessive gingival display with multiple etiologies treated by means of modified lip repositioning technique associated with esthetic crown lengthening. A 23-year-old female patient, with 5-mm gingival display during smile caused by altered passive eruption and hypermobility of the upper lip, underwent the modified lip repositioning technique associated with gingivectomy followed by flap elevation and ostectomy/osteoplasty. Seven months after the second procedure, the patient had her esthetic complaint solved appearing stable in the observation period. The modified lip repositioning technique is an effective procedure employed to reduce gingival display and when associated with esthetic clinical crown lengthening, can appropriately treat cases of gummy smile. PMID:27041845

  10. Genetic linkage map construction and QTL mapping of seedling height, basal diameter and crown width of Taxodium 'Zhongshanshan 302' × T. mucronatum.

    Science.gov (United States)

    Wang, Ziyang; Cheng, Yanli; Yin, Yunlong; Yu, Chaoguang; Yang, Ying; Shi, Qin; Hao, Ziyuan; Li, Huogen

    2016-01-01

    Taxodium is a genus renowned for its fast growth, good form and tolerance of flooding, salt, alkalinity, disease and strong winds. In this study, a genetic linkage map was constructed using sequence-related amplified polymorphism (SRAP) and simple sequence repeat (SSR) markers based on an F1 population containing 148 individuals generated from a cross between T. 'Zhongshanshan 302' and T. mucronatum. The map has a total length of 976.5 cM, with a mean distance of 7.0 cM between markers, and contains 34 linkage groups with 179 markers (171 SRAPs and 8 SSRs). Quantitative trait loci (QTLs) affecting growth traits, such as seedling height, basal diameter and crown width, were detected based on the constructed linkage map. Four significant QTLs were identified, three of which, namely qtSH-1 for seedling height, qtBD-1 for basal diameter and qtCW-1 for crown width, were located at 2.659 cM of LG7 with logarithm odds values of 3.72, 3.49 and 3.93, respectively, and explained 24.9, 27.0 and 21.7 % of the total variation of the three grown traits, respectively. Another QTL for crown width (qtCW-2) was detected at 1.0 cM on LG13, with a logarithm of odds value of 3.15, and explained 31.7 % of the total variation of crown width. This is the first report on the construction of a genetic linkage map and QTL analysis in Taxodium, laying the groundwork for the construction of a high-density genetic map and QTL mapping in the genus Taxodium.

  11. The importance of crown dimensions to improve tropical tree biomass estimates.

    Science.gov (United States)

    Goodman, Rosa C; Phillips, Oliver L; Baker, Timothy R

    2014-06-01

    Tropical forests play a vital role in the global carbon cycle, but the amount of carbon they contain and its spatial distribution remain uncertain. Recent studies suggest that once tree height is accounted for in biomass calculations, in addition to diameter and wood density, carbon stock estimates are reduced in many areas. However, it is possible that larger crown sizes might offset the reduction in biomass estimates in some forests where tree heights are lower because even comparatively short trees develop large, well-lit crowns in or above the forest canopy. While current allometric models and theory focus on diameter, wood density, and height, the influence of crown size and structure has not been well studied. To test the extent to which accounting for crown parameters can improve biomass estimates, we harvested and weighed 51 trees (11-169 cm diameter) in southwestern Amazonia where no direct biomass measurements have been made. The trees in our study had nearly half of total aboveground biomass in the branches (44% +/- 2% [mean +/- SE]), demonstrating the importance of accounting for tree crowns. Consistent with our predictions, key pantropical equations that include height, but do not account for crown dimensions, underestimated the sum total biomass of all 51 trees by 11% to 14%, primarily due to substantial underestimates of many of the largest trees. In our models, including crown radius greatly improves performance and reduces error, especially for the largest trees. In addition, over the full data set, crown radius explained more variation in aboveground biomass (10.5%) than height (6.0%). Crown form is also important: Trees with a monopodial architectural type are estimated to have 21-44% less mass than trees with other growth patterns. Our analysis suggests that accounting for crown allometry would substantially improve the accuracy of tropical estimates of tree biomass and its distribution in primary and degraded forests.

  12. Influence of anatomic reference on the buccal contour of prosthetic crowns

    Directory of Open Access Journals (Sweden)

    Flávia Sabrina Queirós Vasconcelos

    2009-09-01

    Full Text Available During clinical practice, when performing prosthetic rehabilitation with single crowns, improper reproduction of the dental contour by the dental laboratory is a common occurrence. Therefore, the present study evaluated the fidelity of the reproduction of the buccal contour in an upper left canine performed by three Dental Prosthesis Technicians (DPT using the indirect laminate veneer technique. First, the DPTs confected the veneers based on a model obtained from the upper arch of a dental dummy, containing a replica of an upper left canine with a prosthetic preparation for a laminate veneer. Then, the same DPTs received other identical models, now with the replica of the upper left canine with no preparation, to be used as an anatomical reference for confecting the laminate veneers. The laminate veneers were then bonded to the plaster models and had their buccal contour individually measured. Measurements were also made of the buccal contour of the reference canine. The data were analyzed by ANOVA and the t-test (p = 0.05. Results showed 100% of buccal overcontour when the laminate veneers were compared to the reference canine, regardless of which DPT confected the veneer and regardless of using or not the anatomical reference. The DPTs who participated in the present study were unable to acomplish a faithful anatomical reproduction of the buccal contour, creating an overcontour in all samples. This situation may be responsible for increasing the probability of periodontal and esthetic harm in clinical practice.

  13. Clinical outcome of a two-piece implant system with an internal hexagonal connection: a prospective study.

    Science.gov (United States)

    Andreasi Bassi, M; Lopez, M A; Confalone, L; Gaudio, R M; Lombardo, L; Lauritano, D

    2016-01-01

    The purpose of this prospective clinical study was to evaluate the survival rate (SVR - i.e. fixtures still in place at the end of the observation period) and success rate (SCR - i.e. bone resorption around implant neck) of an implant system characterized by cylindrical and tapered implants, both provided with an internal hexagonal connection. In the period between January 1996 and October 2011, 52 implants with internal hexagonal connection were inserted in 21 females and 31 males, mean age 54±11 years. The mean post-surgical follow-up was 44.6±34.4 months. Several parameters were evaluated as potential outcome conditioners: age, gender, smoking, replaced tooth, periodontal disease, fixture shape (i.e. cylindrical or tapered), jaw location (i.e. maxilla or mandible), bone graft, immediate loading, post-extractive placement, type of prosthesis (i.e. single crown or bridge), edentulism, implant diameter and length. An SPSS statistical program was used and Cox regression analysis performed. SVR was 100% since no fixtures were lost. SCR, expressed through the mean marginal bone loss, was 77%. No significant differences were found, for most of the parameters analyzed, with the exception of prosthetic bridges, where implants supporting this type of rehabilitation showed a worse clinical outcome in comparison to single crown rehabilitations. Internal hexagonal connection is a reliable tool for oral rehabilitation. PMID:27469542

  14. AMELOGENESIS IMPERFECTA: A CLINICAL REPORT

    Directory of Open Access Journals (Sweden)

    Veena

    2015-01-01

    Full Text Available AIM: This clinical case report describes the oral rehabilitation of a young adult female patient diagnosed with hypoplastic Amelogenesis imperfecta. SUMMARY : Amelogenesis Imperfecta is a hereditary condition that affects the formation of the enamel mineralization process of both the primary and secondary dentition. It is clinically and genetically heterogeneous grou p of condition that affects both the quantity and quality of the enamel structure resulting in extensive loss of tooth tissue , poor esthetics and tooth sensitivity. The main objective for the selected treatment was to enhance the esthetics , and restoring m asticatory function. Treatment was divided into phases which included removal of impacted canine , lengthening of the maxillary and mandibular clinical crowns , and placement of anterior and posterior crowns.

  15. Zinc isotope effects in benzo crown resin by displacement chromatography

    International Nuclear Information System (INIS)

    The isotope effects of zinc were studied by displacement chromatography with a polymer-supported benzo crown resin packed in glass columns. The influence of migration distance on the zinc isotope effect was investigated. Migration distances from one to thirty meters were performed by feeding zinc chloride in dehydrated acetone solvent into the columns. The migration distance was proved to have no effect on the separation coefficient (ε); however, the migration distance clearly affected the slope coefficient (ks). The height equivalent to a theoretical plate (HETP) was variable for each migration distance in the present work. The slope coefficient ks and HETP were 0.035 and 0.29 cm, respectively, at the 30 m chromatographic operation under 298±1 K in the present work. (author)

  16. The stainless steel crown debate: friend or foe?

    Science.gov (United States)

    Uston, Karen A; Estrella, Maria Regina P

    2011-01-01

    In this article, we will explore the use of the stainless steel crown (SSC) in dentistry today. For the pediatric population, many factors can affect the choice of restoration, such as the variations between primary and permanent tooth morphology, oral environment, and patient selection. The current literature and dentistry guidelines encourage dentists to make an informed decision when determining the restoration recommended for a carious primary molar. To further help educate dental providers on the topic of SSCs the following items will be reviewed: the indications; techniques for placement; advantages; and drawbacks when compared to alternative restorative materials. Regardless of personal opinion, the SSC should continue to be recognized for its efficiency, cost-effectiveness, and successful treatment modality.

  17. Management of Crown Root Fracture by Interdisciplinary Approach

    Directory of Open Access Journals (Sweden)

    K. Radhakrishnan Nair

    2013-01-01

    Full Text Available Fracture of tooth after trauma is distressing to a person because of the discomfort and pain due to pulpal injury. Crown root fractures of anterior teeth cause concomitant periodontal injury and there will be concern about appearance, and aesthetics. Management of pulpal and periodontal tissue relieves pain and restoration of tooth form regains patients confidence. Restoration of fractured tooth will be accepted readily if it is minimally invasive, less expensive, and aesthetically acceptable. Reattachment is an option for restoration of anterior teeth compared to other artificial replacements because of its appearance as natural. This method is favourable when the fractured fragment is intact and available. Utilization of pulp space for retention of fragment is achieved by the insertion of a dentine bonding post. This case report describes a case of tooth reattachment after trauma in which the pulp space is utilized to bond a fiber-reinforced post for retention after periodontal tissue management.

  18. Automatic Tree-Crown Detection in Challenging Scenarios

    Science.gov (United States)

    Bulatov, Dimitri; Wayand, Isabell; Schilling, Hendrik

    2016-06-01

    In this paper, a new procedure for individual tree detection and modeling is presented. The input of this procedure consists of a normalized digital surface model NDSM, and a possibly error-prone classification result. The procedure is modular so that the functionality, the advantages and the disadvantages for every single module will be explained. The most important technical contributions of the paper are: Employing watershed transformation combined with classification results, applying hotspots detectors for identifying treetops in groups of trees, and correcting NDSM by detecting and geometric reconstruction of small anomalies, such as earth walls. Two minor contributions are made up by a detailed literature research on available methods for individual tree detection and estimation of tree-crowns for clearly identified trees in order to reduce arbitrariness by assigning trees to one of the few types in the output model.

  19. Vonlays: a conservative esthetic alternative to full-coverage crowns.

    Science.gov (United States)

    McLaren, Edward A; Figueira, Johan; Goldstein, Ronald E

    2015-04-01

    Porcelain veneers have long been a popular restorative option that have evolved into a well-accepted treatment that can be fabricated in various ways. Onlays are another common treatment modality used in contemporary dentistry to restore large areas of decay and to replace old restorations. With the availability of newer high-strength materials such as lithium disilicate and processing technologies like CAD/CAM and heat pressing, dental professionals are now able to produce highly esthetic, high-strength restorations that blend seamlessly with the natural dentition while also withstanding posterior occlusal forces. This has resulted in innovative methods of providing minimally invasive dentistry. One such approach is a combination restoration the authors call a "vonlay," which, as demonstrated in this case report, can be used as an alternative to coverage crowns to restore damaged posterior teeth. PMID:25821940

  20. 4 '-acetyl benzo-15-crown-5 2-naphthyloxyacetyl hydrazone

    Institute of Scientific and Technical Information of China (English)

    ZHOU Yan-qing; WEI Tai-bao; ZHANG You-ming; ZONG Guo-qiang

    2004-01-01

    Aryloxyacetic acid and its derivatives often possess many important biological activities.Some of them are used as herbicides and plant-growth regulators. In continuation of our previous work on synthesis and biological activities1,2,3, we decided to design series of compounds containing the aryloxyacetyl group and crown ether to study the variation of bioactivities and the effect of the substituents on the ability of the crown ether to bind metal ions4,5. Recently, we determined related crystal structures6,7,8 , in order to study both bioactivities and coordination behaviour. In view of these encouraging results, the structure of the title compound (Figure 1), was obtained and is reported here.Figure 1 The molecule configuration and atom-numbering schem for the title compound,showing ellipsoids at the 50% probability level.Crystals of the ritle compound, C28H32N2O7, is monoclinic, space group P2(1)/c, a = 8.808(3), b =24.579(7), c =11.984(4), α = 90.00, β = 97.248(6), γ = 90.00, Z = 4, Dx= 1. 313 Mg m-3 ,Mo K α, λ =0.71073 , = 9.5mm-1 , F(000) = 1080, T =293(2) K, R = 0.0594, wR=0.1184 for 2575reflections [I>2 σ (Ⅰ) ] .The title compound adopts a syn-anti conformation, which enables N2-H...O6 intermolecule hydrogen bonds to be formed between centrosymmetrically related molecules. The resulting eight-membered rings join these molecules together as characteristic dimmers.

  1. Effect of Different Luting Agents on the Retention of Lithium Disilicate Ceramic Crowns

    Directory of Open Access Journals (Sweden)

    Nicola Mobilio

    2015-04-01

    Full Text Available No studies are available that evaluate the retention of disilicate crowns according to different cementation procedures. The purpose of this study was to measure the retention of lithium disilicate crowns cemented using two different cementation systems. Twenty extracted mandibular premolars were prepared. Anatomic crowns were waxed and hot pressed using lithium disilicate ceramic. Teeth were divided into two groups (n = 10: (1 self-curing luting composite and (2 glass-ionomer cement (GIC. After cementation, the crowns were embedded in acrylic resin block with a screw base. Each specimen was pulled along the path of insertion in Universal Testing Machine. Failure load in Newtons (N and failure mode were recorded for each specimen. Failure mode was classified as decementation or fracture. Failure load data were analyzed using one-way analysis of variance (ANOVA. Failure modes were compared using Pearson’s Chi-square test. Mean failure load was 306.6(±193.8 N for composite group and 94.7(±48.2 N for GIC group (p = 0.004. Disilicate crown cemented with luting composite most often failed by fracture; otherwise, crown cemented with glass-ionomer cement most often failed by decementation (p = 0.02. Disilicate full crown cemented with luting composite showed higher failure load compared with conventional cementation with glass-ionomer cement.

  2. Comparative in vitro evaluation of CAD/CAM vs conventional provisional crowns

    Science.gov (United States)

    ABDULLAH, Adil Othman; TSITROU, Effrosyni A; POLLINGTON, Sarah

    2016-01-01

    ABSTRACT Objective This study compared the marginal gap, internal fit, fracture strength, and mode of fracture of CAD/CAM provisional crowns with that of direct provisional crowns. Material and Methods An upper right first premolar phantom tooth was prepared for full ceramic crown following tooth preparation guidelines. The materials tested were: VITA CAD-Temp®, Polyetheretherketone “PEEK”, Telio CAD-Temp, and Protemp™4 (control group). The crowns were divided into four groups (n=10), Group1: VITA CAD-Temp®, Group 2: PEEK, Group 3: Telio CAD-Temp, and Group 4: Protemp™4. Each crown was investigated for marginal and internal fit, fracture strength, and mode of fracture. Statistical analysis was performed using GraphPad Prism software version 6.0. Results The average marginal gap was: VITA CAD-Temp® 60.61 (±9.99) µm, PEEK 46.75 (±8.26) µm, Telio CAD-Temp 56.10 (±5.65) µm, and Protemp™4 193.07(±35.96) µm (P0.05). Conclusions CAD/CAM fabricated provisional crowns demonstrated superior fit and better strength than direct provisional crowns. PMID:27383707

  3. A ferric-cyanide-bridged one-dimensional dirhodium complex with (18-crown-6)potassium cations.

    Science.gov (United States)

    Kim, Y; Kim, S J; Nam, W

    2001-03-01

    The crystal structure of the title compound, catena-poly[bis[aqua(18-crown-6)potassium] diaqua(18-crown-6)potassium [[tetra-mu-benzoato-2:3 kappa(8)O:O'-mu-cyano-1:2 kappa(2)C:N-tetracyano-1 kappa C-irondirhodium(Rh-Rh)]-mu-cyano-1 kappa C:3' kappa N] octahydrate], [K(18-crown-6)(H(2)O)](2)[K(18-crown-6)(H(2)O)(2)][FeRh(2)(C(7)H(5)O(2))(4)(CN)(6)] x 8H(2)O, where (18-crown-6) is 1,4,7,10,13,16-hexaoxacyclooctadecane (C(12)H(24)O(6)), has been determined. Ferric cyanides connect the dirhodium units to form a one-dimensional chain compound. [K(18-crown-6-ether)(H(2)O)(2)] cations (with inversion symmetry) and [K(18-crown-6-ether)(H(2)O)] cations (in general positions) are located between the chains. PMID:11250572

  4. Olive Crown Porosity Measurement Based on Radiation Transmittance: An Assessment of Pruning Effect

    Science.gov (United States)

    Castillo-Ruiz, Francisco J.; Castro-Garcia, Sergio; Blanco-Roldan, Gregorio L.; Sola-Guirado, Rafael R.; Gil-Ribes, Jesus A.

    2016-01-01

    Crown porosity influences radiation interception, air movement through the fruit orchard, spray penetration, and harvesting operation in fruit crops. The aim of the present study was to develop an accurate and reliable methodology based on transmitted radiation measurements to assess the porosity of traditional olive trees under different pruning treatments. Transmitted radiation was employed as an indirect method to measure crown porosity in two olive orchards of the Picual and Hojiblanca cultivars. Additionally, three different pruning treatments were considered to determine if the pruning system influences crown porosity. This study evaluated the accuracy and repeatability of four algorithms in measuring crown porosity under different solar zenith angles. From a 14° to 30° solar zenith angle, the selected algorithm produced an absolute error of less than 5% and a repeatability higher than 0.9. The described method and selected algorithm proved satisfactory in field results, making it possible to measure crown porosity at different solar zenith angles. However, pruning fresh weight did not show any relationship with crown porosity due to the great differences between removed branches. A robust and accurate algorithm was selected for crown porosity measurements in traditional olive trees, making it possible to discern between different pruning treatments. PMID:27213391

  5. MnBr2/18-crown-6 coordination complexes showing high room temperature luminescence and quantum yield.

    Science.gov (United States)

    Hausmann, David; Kuzmanoski, Ana; Feldmann, Claus

    2016-04-12

    The reaction of manganese(ii) bromide and the crown ether 18-crown-6 in the ionic liquid [(n-Bu)3MeN][N(Tf)2] under mild conditions (80-130 °C) resulted in the formation of three different coordination compounds: MnBr2(18-crown-6) (), Mn3Br6(18-crown-6)2 () and Mn3Br6(18-crown-6) (). In general, the local coordination and the crystal structure of all compounds are driven by the mismatch between the small radius of the Mn(2+) cation (83 pm) and the ring opening of 18-crown-6 as a chelating ligand (about 300 pm). This improper situation leads to different types of coordination and bonding. MnBr2(18-crown-6) represents a molecular compound with Mn(2+) coordinated by two bromine atoms and only five oxygen atoms of 18-crown-6. Mn3Br6(18-crown-6)2 falls into a [MnBr(18-crown-6)](+) cation - with Mn(2+) coordinated by six oxygen atoms and Br - and a [MnBr(18-crown-6)MnBr4](-) anion. In this anion, Mn(2+) is coordinated by five oxygen atoms of the crown ether as well as by two bromine atoms, one of them bridging to an isolated (MnBr4) tetrahedron. Mn3Br6(18-crown-6), finally, forms an infinite, non-charged [Mn2(18-crown-6)(MnBr6)] chain. Herein, 18-crown-6 is exocyclically coordinated by two Mn(2+) cations. All compounds show intense luminescence in the yellow to red spectral range and exhibit remarkable quantum yields of 70% (Mn3Br6(18-crown-6)) and 98% (Mn3Br6(18-crown-6)2). The excellent quantum yield of Mn3Br6(18-crown-6)2 and its differentiation from MnBr2(18-crown-6) and Mn3Br6(18-crown-6) can be directly correlated to the local coordination. PMID:26956783

  6. Fracture resistance of a selection of full-contour all-ceramic crowns: an in vitro study.

    Science.gov (United States)

    Zesewitz, Tim F; Knauber, Andreas W; Northdurft, Frank P

    2014-01-01

    This study aimed to evaluate the fracture resistance of monolithic single crowns made from zirconia (ZI), lithium disilicate (LS2), or feldspar ceramic (FC). Five groups of crowns representing a maxillary first molar were made with the appropriate dimensions according to the manufacturer's instructions. The ZI and LS2 crowns were luted adhesively or cemented conventionally on a metal abutment tooth analog. The feldspar ceramic crowns were luted adhesively. All specimens underwent axial loading until fracture. The crowns in the ZI groups possessed the highest fracture resistance independent of the mode of fixation.

  7. Clinical evaluation of residual crowns and roots restored by glass fiber post and core, cast metal post and core or directly%玻璃纤维桩核与铸造金属桩核修复残根残冠及无桩修复牙体的临床效果评价

    Institute of Scientific and Technical Information of China (English)

    马洪学; 申丽丽; 刘琨; 苏林旺

    2013-01-01

    目的 评价玻璃纤维桩核与铸造金属桩核修复残根残冠及无桩修复根管治疗后残冠的生存率和并发症.方法 96名患者共142颗患牙进行根管充填,然后依据不同的情况进行玻璃纤维桩核、铸造纯钛桩核、无桩固位的全冠修复.结果 在89名患者的135颗牙齿中,73颗牙齿(54.1%)使用玻璃纤维桩修复、复合树脂桩核,最后进行金瓷冠或全瓷冠修复,在(5.7±1.9)年平均观察期内的留存率达到97.3%; 40颗牙齿采用铸造纯钛桩核修复,在(6.2±2.2)年平均观察期内的留存率达到了87.5%;22颗牙齿采用无桩修复,在(54±1.8)年平均观察期内的留存率是90.9%.玻璃纤维桩、铸造纯钛桩核、无桩修复的患牙三者间的成功率差异无统计学意义.修复最常见的并发症包括:根折(6.7%)、固位丧失(2.2%)、继发龋(1.5%)、根尖周炎(0.7%).结论 在实施高质量的根管治疗和规范的修复操作技术的前提下,无论是玻璃纤维桩修复还是铸造金属桩核修复或无桩修复的基牙在超过5年的观察期内均能获得较高的留存率,但并发症尤其是根折裂应引起必要的重视.%Objective To evaluate the survival rate and complications of endodontically treated residual crowns and roots restored directly or by glass fiber post and core or cast metal post and core. Methods In this study, 96 patients with a total of 142 teeth were selected. All the teeth were undergone root canal therapy. And then, according to different situations, some of them were restored with glass fiber post and core, another with cast metal post and core, the rest were restored directly in the strict controlled indications. Results The teeth (135) in 89 patients were divided into three groups. The first group contained 73(54.1%) teeth restored with glass fiber post and composite resin core. The survival rate reached 97.3% in the average observation period of (5.7±1.9) years. The second group

  8. Evaluation of different sterilization and disinfection methods on commercially made preformed crowns.

    Science.gov (United States)

    Yilmaz, Y; Guler, C

    2008-12-01

    The aim of this study was to evaluate the changes caused by different sterilization or disinfection methods on the vestibular surface of four commercially made preformed crowns using stereomicroscopy and scanning electron microscopy (SEM). Preformed crowns (NuSmile Primary Anterior Crown (NSC), Kinder Krowns (KK), Pedo Pearls (PP) and polycarbonate crowns (PC)) were sterilized and/or disinfected by one of the following techniques: no sterilization or disinfection (G1 control group); steam autoclaving at 134 degrees C (30 psi) for 4 min (G2); steam autoclaving at 134 degrees C (30 psi) for 12 min (G3); steam autoclaving at 121 degrees C (15 psi) for 30 min (G4); and ultrasonication in a bath containing 4% Lysetol AF for 5 min at room temperature (chemical disinfection) (G5). Scanning electron micrographs of the crowns were taken before and after their sterilization or disinfection. The changes on the vestibular surface were then scored for the presence or absence of crazing, contour alteration, fracturing, and vestibular surface changes. The data were analyzed statistically using the chi-square test. No changes were observed before and after sterilization or disinfection in the stereomicroscopic evaluation of the vestibular surface of the crowns. However, all methods in which steam autoclaving was used to sterilize the crowns caused significant (P < 0.05) crazing and contour alterations of the vestibular surface of the crowns when they were examined by SEM. Chemical disinfection using an aldehyde-free disinfectant is the preferred method of disinfection for crowns that have been used previously in other dental patients. PMID:19008625

  9. Evaluation of different sterilization and disinfection methods on commercially made preformed crowns

    Directory of Open Access Journals (Sweden)

    Yilmaz Y

    2008-01-01

    Full Text Available The aim of this study was to evaluate the changes caused by different sterilization or disinfection methods on the vestibular surface of four commercially made preformed crowns using stereomicroscopy and scanning electron microscopy (SEM. Preformed crowns (NuSmile Primary Anterior Crown (NSC, Kinder Krowns (KK, Pedo Pearls (PP and polycarbonate crowns (PC were sterilized and/or disinfected by one of the following techniques: no sterilization or disinfection (G1 control group; steam autoclaving at 134 °C (30 psi for 4 min (G2; steam autoclaving at 134 °C (30 psi for 12 min (G3; steam autoclaving at 121 °C (15 psi for 30 min (G4; and ultrasonication in a bath containing 4% Lysetol ® AF for 5 min at room temperature (chemical disinfection (G5. Scanning electron micrographs of the crowns were taken before and after their sterilization or disinfection. The changes on the vestibular surface were then scored for the presence or absence of crazing, contour alteration, fracturing, and vestibular surface changes. The data were analyzed statistically using the chi-square test. No changes were observed before and after sterilization or disinfection in the stereomicroscopic evaluation of the vestibular surface of the crowns. However, all methods in which steam autoclaving was used to sterilize the crowns caused significant (P < 0.05 crazing and contour alterations of the vestibular surface of the crowns when they were examined by SEM. Chemical disinfection using an aldehyde-free disinfectant is the preferred method of disinfection for crowns that have been used previously in other dental patients.

  10. Evaluation of different sterilization and disinfection methods on commercially made preformed crowns.

    Science.gov (United States)

    Yilmaz, Y; Guler, C

    2008-12-01

    The aim of this study was to evaluate the changes caused by different sterilization or disinfection methods on the vestibular surface of four commercially made preformed crowns using stereomicroscopy and scanning electron microscopy (SEM). Preformed crowns (NuSmile Primary Anterior Crown (NSC), Kinder Krowns (KK), Pedo Pearls (PP) and polycarbonate crowns (PC)) were sterilized and/or disinfected by one of the following techniques: no sterilization or disinfection (G1 control group); steam autoclaving at 134 degrees C (30 psi) for 4 min (G2); steam autoclaving at 134 degrees C (30 psi) for 12 min (G3); steam autoclaving at 121 degrees C (15 psi) for 30 min (G4); and ultrasonication in a bath containing 4% Lysetol AF for 5 min at room temperature (chemical disinfection) (G5). Scanning electron micrographs of the crowns were taken before and after their sterilization or disinfection. The changes on the vestibular surface were then scored for the presence or absence of crazing, contour alteration, fracturing, and vestibular surface changes. The data were analyzed statistically using the chi-square test. No changes were observed before and after sterilization or disinfection in the stereomicroscopic evaluation of the vestibular surface of the crowns. However, all methods in which steam autoclaving was used to sterilize the crowns caused significant (P < 0.05) crazing and contour alterations of the vestibular surface of the crowns when they were examined by SEM. Chemical disinfection using an aldehyde-free disinfectant is the preferred method of disinfection for crowns that have been used previously in other dental patients.

  11. Curve Length Estimation using Vertix Chain Code Curve Length Estimation

    Directory of Open Access Journals (Sweden)

    Habibollah Haron

    2010-09-01

    Full Text Available Most of the applications in image analysis are based on Freeman chain code. In this paper, for the first time, vertex chain code (VCC proposed by Bribiesca is applied to improve length estimation of the 2D digitized curve. The chain code has some preferences such as stable in shifting, turning, mirroring movement of image and has normalized starting point. Due to the variety of length estimator methods, we focused on the three specific techniques. First, the way Bribiesca proposed which is based on counting links between vertices; second, based on maximum length digital straight segments (DSSs and lastly local metrics. The results of these length estimators with the real perimeter are compared. Results thus obtained exhibits thatlength estimation using VCC is nearest to the actual length.

  12. Polyketide chain length control by chain length factor.

    Science.gov (United States)

    Tang, Yi; Tsai, Shiou-Chuan; Khosla, Chaitan

    2003-10-22

    Bacterial aromatic polyketides are pharmacologically important natural products. A critical parameter that dictates product structure is the carbon chain length of the polyketide backbone. Systematic manipulation of polyketide chain length represents a major unmet challenge in natural product biosynthesis. Polyketide chain elongation is catalyzed by a heterodimeric ketosynthase. In contrast to homodimeric ketosynthases found in fatty acid synthases, the active site cysteine is absent from the one subunit of this heterodimer. The precise role of this catalytically silent subunit has been debated over the past decade. We demonstrate here that this subunit is the primary determinant of polyketide chain length, thereby validating its designation as chain length factor. Using structure-based mutagenesis, we identified key residues in the chain length factor that could be manipulated to convert an octaketide synthase into a decaketide synthase and vice versa. These results should lead to novel strategies for the engineered biosynthesis of hitherto unidentified polyketide scaffolds.

  13. Complexation between Methyl Viologen (Paraquat) Bis(Hexafluorophosphate) and Dibenzo[24]Crown-8 Revisited

    DEFF Research Database (Denmark)

    Gasa, Travis B.; Spruell, Jason M.; Dichtel, William R.;

    2009-01-01

    Paraquat bis(hexafluorophosphate) undergoes stepwise dissociation in acetone. All three species - the neutral molecule, and the mono- and dications - are represented significantly under the experimental conditions typically used in host-guest binding studies. Paraquat forms at least four host...... toward dibenzo[24]crown-8. Thus, the relative abundance of neutral, singly, and doubly charged pseudorotaxanes is identical to the relative abundance of neutral, singly, and doubly charged paraquat unbound with respect to the crown ether in acetone. In the specific case of paraquat/dibenzo[24]crown-8...

  14. Formation of the biologic width following crown lengthening in nonhuman primates.

    Science.gov (United States)

    Oakley, E; Rhyu, I C; Karatzas, S; Gandini-Santiago, L; Nevins, M; Caton, J

    1999-12-01

    The purpose of this study was to determine if and how the biologic width is reestablished following surgical crown lengthening. Crown-lengthening surgery was performed on the right or left maxillary and mandibular central and lateral incisors of three adult monkeys, with contralateral teeth serving as unoperated controls. Twelve weeks after surgery, tissue blocks were removed for histologic analysis. The results of a histometric evaluation indicate that the biologic width is reestablished following surgical crown lengthening. The junctional epithelium generally migrates to the apical level of root planing. Space for the supracrestal connective tissue fiber groups is created by crestal resorption of alveolar bone.

  15. Evaluation of various Crown ethers for the supercritical fluid extraction of uranium from nitric acid medium

    International Nuclear Information System (INIS)

    Various crowns have been evaluated for supercritical fluid extraction of uranium from nitric acid medium employing HPFOA as counter ion. Uranium extraction efficiency was found to be influenced by cavity size of crown ether and nature of substituents. Complexation tendency of UO22+ increases with increasing cavity size of crown ether. Electron withdrawing substituents decreased the extraction efficiency which could be attributed to decrease in the basicity of four oxygen atoms and hence their bonding ability. Whereas electron donating substituents increased the efficiency due to increases in basicity of oxygen atoms and hence in increase in bonding ability. (author)

  16. Study and application of crown feedback control in hot strip rolling

    Institute of Scientific and Technical Information of China (English)

    Xiaodong Wang; Anrui He; Quan Yang; Zhi Xie; Hongtao Yang

    2007-01-01

    Crown feedback control is one part of the automatic shape control (ASC) system. On the basis of large simulation researches conducted, a linear crown feedback control model was put forward and applied in actual strip rolling. According to its successful operation in the ASP 1700 hot strip mill of Angang Group for one year and also from the statistical results of several crown measurements, it can be definitely said that this control model is highly effective and shows stable performance. The control effectiveness of different gauges of strips with the feedback control is found to increase by 10%-30% compared with that without feedback control.

  17. Were king Stefan the First-Crowned and his son Radoslav co-rulers?

    OpenAIRE

    Bubalo Đorđe

    2009-01-01

    The Serbian historiography considers the issue of the co-ruling of King Stefan the First-Crowned and his son Radoslav as the one finally resolved. The suggested solution on the co-rule of Stefan and Radoslav may be most succinctly expressed as following: as early as in the year of 1220, due to the frail health of Stefan the First-Crowned and Radoslav's marriage to Anne the Epirus princess, Radoslav was crowned to be the king and positioned to co-rule with his father after the Byzantine model ...

  18. Strength of CAD/CAM-generated esthetic ceramic molar implant crowns

    OpenAIRE

    Wolf, D; Bindl, A; Schmidlin, P R; Lüthy, H; Mörmann, W H

    2008-01-01

    PURPOSE: One-visit in-office CAD/CAM fabrication of esthetic ceramic crowns as a superstructure for posterior implants is quite new. The aim of the study was to evaluate the strength of esthetic ceramic CAD/CAM crowns with varied occlusal thickness and seated with adhesive and nonadhesive cements on titanium and zirconia abutments. MATERIALS AND METHODS: Esthetic ceramic CAD/CAM-generated molar crowns (n = 15 per group) with occlusal thicknesses of 0.5 mm and 1.5 mm were seated on titanium (1...

  19. A biological approach to crown fracture: Fracture reattachment: A report of two cases

    Science.gov (United States)

    Vijayaprabha, K.; Marwah, Nikhil; Dutta, Samir

    2012-01-01

    The development of adhesive dentistry has allowed dentists to use the patient's own fragment to restore the fractured tooth, which is considered to be the most conservative method of treatment of crown fracture allowing restoration of original dental anatomy, thus rehabilitating function and esthetics in a short time by preserving dental tissues. The tooth fragment reattachment is preferred over full coverage crowns or composite resin restoration because it conserves sound tooth structure, and is more esthetic, maintaining the original anatomy and translucency, and the rate of incisal wear also matches that of original tooth structure. Presented here is a report of two cases of crown fracture managed by reattachment procedures. PMID:23230362

  20. Wave Forces and Overtopping on Crown Walls of Rubble Mound Breakwaters

    DEFF Research Database (Denmark)

    Pedersen, Jan

    in the coastal laboratory at Aalborg University. Based on analyses of experimental data a design method for assessing the maximum wave forces on the vertical face of the crown wall structures has been developed as well as new and more versatile design equation for the related overtopping discharges...... of rubble mound breakwater crown walls. This background motivated the initialization of the present study on wave imposed forces and wave overtopping on crown wall structures. The two subjects where investigated through an excessive parametric model study involving more than 370 long duration test series...