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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

    as controls. Paired sample t-testand Pearson´s correlation analysis were used to analyze implant position, dimension of crownand papilla fill.Cohen’s ¿ andSpearman correlation were used to validate the PIS.The implant-supported crown was statistically longer than the contra-lateral tooth......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......, and there was significant correlation between the oro-facial position of the implant and the crown length difference (r=.607, p=.001). The distalpapilla was significantly shorter than the mesialpapilla at implant-supported crowns (p

  2. Gingival contour and clinical crown length: their effect on the esthetic appearance of maxillary anterior teeth.

    Science.gov (United States)

    Kokich, V G; Nappen, D L; Shapiro, P A

    1984-08-01

    Fractured, congenitally missing, or avulsed maxillary incisors can often jeopardize the esthetic appearance of the remaining maxillary anterior teeth after orthodontic treatment. In many cases the unesthetic appearance is related to the irregular clinical crown lengths of either the fractured teeth or those that have been substituted for the missing teeth. The results of five cases with either fractured or traumatically avulsed central incisors are reported. Selective tooth intrusion and restorative techniques were used during the finishing stages of orthodontic treatment to improve the final esthetic result. The advantages and disadvantages of the intrusion technique are discussed.

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

    Directory of Open Access Journals (Sweden)

    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.

  4. 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.

  5. Short clinical crowns (SCC) – treatment considerations and techniques

    OpenAIRE

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

    2012-01-01

    When the clinical crowns of teeth are dimensionally inadequate, esthetically and biologically acceptable restoration of these dental units is difficult. Often an acceptable restoration cannot be accomplished without first surgically increasing the length of the existing clinical crowns; therefore, successful management requires an understanding of both the dental and periodontal parameters of treatment. The complications presented by teeth with short clinical crowns demand a comprehensive tre...

  6. FETAL FOOT LENGTH AND HAND LENGTH: RELATIONSHIP WITH CROWN RUMP LENGTH AND GESTATIONAL AGE

    Directory of Open Access Journals (Sweden)

    Garima

    2015-12-01

    Full Text Available BACKGROUND Estimation of gestational age of fetus is of great medicolegal importance. Multiple parameters of the fetal anatomical measurements are in use. However, gestational age assessment may be difficult in fetus with anencephaly, hydrocephalus, short limb dysplasia, post mortem destruction or in mutilated case. Study of literature suggests that fetal foot has a characteristic pattern of normal growth and the fetal foot shows gradual increase in length relative to the length of the embryo and could be used to estimate gestational age. The purpose of the present study is to determine the accuracy in estimating gestational age using fetal foot and hand length by studying its relation with crown rump length in the foetuses of Manipuri origin. AIMS AND OBJECTIVES 1 To study the relationship between fetal crown rump length and fetal hand and foot length, thereby determining the accuracy in estimating gestational age by a cross-sectional study. MATERIALS AND METHODS A total of 100 formalin fixed fetuses of Manipuri origin, obtained from the Department of Obstetrics and Gynaecology, Regional Institute of Medical Sciences, Imphal, were included in the study, carried out in the Department of Anatomy, from February 2015 to July 2015. The parameters studied were crown rump length, foot length and hand length of fetuses. The data was analysed using SPSS software by regression analysis. Graphs were also plotted to determine pattern of growth and their correlation with crown rump length if any. RESULTS A total of 100 fetuses were studied, of which 43 were females and 57 were males. The mean foot length and hand length progressively increased with increase in crown rump length. Measurements were not significantly different in right or left side or among male and female fetuses. A statistically significant linear relationship was seen between foot length and crown rump length of the fetus (r=0.980, p<0.0001 and hand length and crown rump length of the fetus

  7. 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

  8. Classifying stages of third molar development: crown length as a predictor for the mature root length.

    Science.gov (United States)

    Altalie, Salem; Thevissen, Patrick; Willems, Guy

    2015-01-01

    Multiple tooth development staging techniques were reported based on arbitrarily set borderlines between succeeding stages. Anatomic tooth features or predictions of future tooth part dimensions were described to identify the thresholds between the established stages. The need to predict mature tooth dimensions, while the tooth considered is still in development, is a drawback to use this staging technique for dental age estimations. Using the fully mature crown length as a predictor for the future root length could provide a tool for undisputable staging. The aim of this study was first to measure the crown and root length of fully mature third molars and second to investigate whether the crown length could be used as a predictor of the root length, in order to classify the observed root length as a proportion of the future mature root. The crown and root lengths of all present third molars were digitally measured on dental panoramic radiographs of 1,000 subjects. The included subjects were equally distributed in gender, and their age ranged between 22 and 40 years. Two occlusal borders, the cement enamel junction and the root apices, were defined as landmarks for standardized measurements. Regression models with root length as response and crown length as predictor were established and revealed low R (2) and high RMSE values. Due to the small explained variance by the prediction models and the high variation in prediction errors, the observed crown length cannot be used to predict the final root length of a developing third molar.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. [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.

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

    OpenAIRE

    2012-01-01

    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....

  17. 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.

  18. 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.

  19. 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. PMID:26609452

  20. Aesthetic Surgical Crown Lengthening Procedure

    Directory of Open Access Journals (Sweden)

    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.

  1. 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.

  2. Aesthetic Surgical Crown Lengthening Procedure

    OpenAIRE

    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 h...

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

    OpenAIRE

    Ramya Nethravathy; Santhana Krishnan Vinoth; Ashwin Varghese Thomas

    2013-01-01

    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 clinical...

  4. 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.

  5. [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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. Complication rate of molar crowns: a practice-based clinical evaluation.

    Science.gov (United States)

    Rinke, S; Schäfer, S; Roediger, M

    2011-01-01

    This practice-based study evaluates the initial clinical performance of conventionally luted metal-ceramic and zirconia molar crowns fabricated with a prolonged cooling period of the veneering porcelain. Forty-nine patients were treated (group A: high precious alloy + low fusing porcelain; group B: zirconia crowns). All zirconia crowns were veneered with a modified porcelain firing cycle including a 6-minute cooling period. Ninety-two restorations (74 vital abutments/18 nonvital abutments) were evaluated after a mean observation period of 18.2 +/- 4.6 months. No complete failures or loss of vitality were recorded in either group. Two events were recorded in group A (1 loss of retention/1 minor ceramic chipping zirconia crowns fabricated with a modified porcelain firing. The modified firing of the zirconia porcelain seems to decrease the risk for early ceramic chipping in the molar area, leading to a technical complication rate comparable to that of metal-ceramic crowns.

  12. 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

    INTRODUCTION: Apical surgery is an important treatment option for teeth with post-treatment periodontitis. Although apical surgery involves root-end resection, no morphometric data are yet available about root-end resection and its impact on the root-to-crown ratio (RCR). The present study assess...

  13. Mirror-image anterior crown fabrication with computer-aided design and rapid prototyping technology: a clinical report.

    Science.gov (United States)

    Cho, Seok-Hwan; Chang, Won-Gun

    2013-02-01

    This clinical report describes the fabrication of a maxillary central incisor single crown with rapid prototyping (RP) technology. A patient with a recently replaced metal ceramic crown had discomfort due to the nonanatomic lingual contour of the crown. With computer-aided design (CAD) software and rapid prototyping (RP) technology, the shape of the contralateral central incisor was duplicated and reproduced to make a mirror-image for a new crown. The prosthodontic planning and treatment approach are discussed.

  14. 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

    2016-10-01

    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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.)

  19. 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

  20. 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 all...... twin pregnancies with two live fetuses scanned between 11 and 14 weeks' gestation during the period 1 January 2004 to 31 December 2006. The association between CRL discordance ≥ 10 % and adverse outcome was evaluated. RESULTS: Among 1993 twin pregnancies, 1733 were dichorionic (156 (9%) discordant......; 1577 (91%) concordant) and 260 were monochorionic (32 (12%) discordant; 228 (88%) concordant). In dichorionic twin pregnancies we found an association between CRL discordance ≥ 10% and preterm delivery before 34 weeks' gestation (P=0.007), birth weight discordance (P=0.001) and mean birth weight (P=0...

  1. Metal-ceramic dowel crown restorations for severely damaged teeth: A clinical report

    Directory of Open Access Journals (Sweden)

    Yuzugullu Bulem

    2009-01-01

    Full Text Available This clinical report describes an alternative prosthodontic treatment of a patient who had severely damaged endodontically-treated first molar teeth in all quadrants of her mouth. The young patient′s severely damaged permanent molar teeth were treated with a restoration combining the advantage of the esthetics of dental porcelain, reinforced with the underlying cast gold dowel crown. Using this technique, the remaining sound tooth structure was preserved with function and esthetics accomplished. The described metal-ceramic one piece dowel crown restoration seemed to perform without any problems for the 12 month evaluation time.

  2. Clinical management of crown-root fracture due to occlusal interference

    OpenAIRE

    2015-01-01

    This clinical report describes a crown-root fracture of the upper right central incisor associated with compromised anterior dental aesthetics. Occlusal adjustment and aesthetic rehabilitation were achieved by using single-tooth restorations with IPS e.max Press®. The precepts of occlusion were observed to establish an optimal occlusion in terms of static and dynamic mandibular movement. Five-year follow-up demonstrated that the clinical protocol used was successful, providing periodontal tis...

  3. 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.

  4. Clinical Acceptability of the Internal Gap of CAD/CAM PD-AG Crowns Using Intraoral Digital Impressions.

    Science.gov (United States)

    Kim, Tae-Gyung; Kim, Sungtae; Choi, Hyunmin; Lee, Jae-Hoon; Kim, Jae-Hong; Moon, Hong-Seok

    2016-01-01

    The purpose of this study was to compare the internal gap between CAD/CAM palladium-silver crowns and cast gold crowns generated from intraoral digital versus conventional impressions and to determine the clinical acceptability. Nickel-chrome master dies were made from the prepared resin tooth with the conventional impression method (n = 40). For ICC (Intraoral, CAD/CAM) group, 10 intraoral digital impressions were made, and 10 CAD/CAM crowns of a PD-AG (palladium-silver) machinable alloy were generated. For IC (Intraoral, Cast) group, 10 gold crowns were cast from ten intraoral digital impressions. For CCC (Conventional, CAD/CAM) group, 10 CAD/CAM PD-AG crowns were made using the conventional impression method. For CC (Conventional, Cast) group, 10 gold crowns were fabricated from 10 conventional impressions. One hundred magnifications of the internal gaps of each crown were measured at 50 points with an optical microscope and these values were statistically analyzed using a two-way analysis of variance (α = 0.05). The internal gap of the intraoral digital impression group was significantly larger than in the conventional impression group (P CAD/CAM group and the cast group (P > 0.05). Within the limitations of this in vitro study, crowns from intraoral digital impressions showed larger internal gap values than crowns from conventional impressions.

  5. Clinical Acceptability of the Internal Gap of CAD/CAM PD-AG Crowns Using Intraoral Digital Impressions

    Directory of Open Access Journals (Sweden)

    Tae-Gyung Kim

    2016-01-01

    Full Text Available The purpose of this study was to compare the internal gap between CAD/CAM palladium-silver crowns and cast gold crowns generated from intraoral digital versus conventional impressions and to determine the clinical acceptability. Nickel-chrome master dies were made from the prepared resin tooth with the conventional impression method (n=40. For ICC (Intraoral, CAD/CAM group, 10 intraoral digital impressions were made, and 10 CAD/CAM crowns of a PD-AG (palladium-silver machinable alloy were generated. For IC (Intraoral, Cast group, 10 gold crowns were cast from ten intraoral digital impressions. For CCC (Conventional, CAD/CAM group, 10 CAD/CAM PD-AG crowns were made using the conventional impression method. For CC (Conventional, Cast group, 10 gold crowns were fabricated from 10 conventional impressions. One hundred magnifications of the internal gaps of each crown were measured at 50 points with an optical microscope and these values were statistically analyzed using a two-way analysis of variance (α=0.05. The internal gap of the intraoral digital impression group was significantly larger than in the conventional impression group (P0.05. Within the limitations of this in vitro study, crowns from intraoral digital impressions showed larger internal gap values than crowns from conventional impressions.

  6. Practice-based clinical evaluation of metal-ceramic and zirconia molar crowns: 3-year results.

    Science.gov (United States)

    Rinke, S; Schäfer, S; Lange, K; Gersdorff, N; Roediger, M

    2013-03-01

    This practice-based study evaluates the clinical performance of conventionally luted metal-ceramic and zirconia molar crowns fabricated with pronounced anatomical core design and a prolonged cooling period of the veneering porcelain. Fifty-three patients were treated from 07/2008 until 07/2009 with either metal-ceramic crowns (MCC) (high-noble alloy + low-fusing porcelain) or zirconia crowns (Cercon System, DeguDent, Germany). Forty-nine patients (30 women/19 men) with 100 restorations (metal-ceramic: 48/zirconia: 52, mean observational period: 36·5 ± 6 months) participated in a clinical follow-up examination and were included in the study. Time-dependent survival (in situ criteria), success (event-free restorations) and chipping rates (defects of the veneering ceramics) were calculated according to the Kaplan-Meier method and analysed in relation to the crown fabrication technique, using a Cox regression model (P zirconia: 2) were recorded (survival rate after 3 years: metal-ceramic: 97·6%, zirconia: 95·2%). Of the metal-ceramic restorations, 90·9% remained event-free (two ceramic fractures, one endodontic treatment), whereas the success rate for the zirconia was 86·8% (two ceramic fractures, one endodontic treatment, one secondary caries). No significant differences in survival (P = 0·53), success (P = 0·49) and ceramic fracture rates (P = 0·57) were detected. The combination of a pronounced anatomical core design and a modified firing of the veneering porcelain for the fabrication of zirconia molar crowns resulted in a 3-year survival, success and chipping rate comparable to MCC.

  7. 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

  8. Probabilistic divergence time estimation without branch lengths: dating the origins of dinosaurs, avian flight and crown birds

    Science.gov (United States)

    2016-01-01

    Branch lengths—measured in character changes—are an essential requirement of clock-based divergence estimation, regardless of whether the fossil calibrations used represent nodes or tips. However, a separate set of divergence time approaches are typically used to date palaeontological trees, which may lack such branch lengths. Among these methods, sophisticated probabilistic approaches have recently emerged, in contrast with simpler algorithms relying on minimum node ages. Here, using a novel phylogenetic hypothesis for Mesozoic dinosaurs, we apply two such approaches to estimate divergence times for: (i) Dinosauria, (ii) Avialae (the earliest birds) and (iii) Neornithes (crown birds). We find: (i) the plausibility of a Permian origin for dinosaurs to be dependent on whether Nyasasaurus is the oldest dinosaur, (ii) a Middle to Late Jurassic origin of avian flight regardless of whether Archaeopteryx or Aurornis is considered the first bird and (iii) a Late Cretaceous origin for Neornithes that is broadly congruent with other node- and tip-dating estimates. Demonstrating the feasibility of probabilistic time-scaling further opens up divergence estimation to the rich histories of extinct biodiversity in the fossil record, even in the absence of detailed character data. PMID:28336787

  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 perfo......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......-trimester screening. The correct method of GA dating for other purposes (e.g. estimated time of delivery) in IVF/ICSI pregnancies is still unresolved Udgivelsesdato: 2008/10...

  10. 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.

  11. 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.

  12. 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

  13. 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.

  14. 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 ...

  15. 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.

  16. The rehabilitation of an edentulous mandible with a CAD/CAM zirconia framework and heat-pressed lithium disilicate ceramic crowns: a clinical report.

    Science.gov (United States)

    Cho, Youngwook; Raigrodski, Ariel J

    2014-06-01

    This clinical report describes a complete arch, implant-supported prosthesis with a zirconia framework and monolithic lithium disilicate crowns. The design of the computer-aided design/computer-aided manufacturing zirconia framework with cemented crowns with screw access is useful in facilitating retrievability and adequate fit, and may reduce the likelihood of porcelain chipping.

  17. 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.

  18. Age, CAG repeat length, and clinical progression in Huntington's disease.

    Science.gov (United States)

    Rosenblatt, Adam; Kumar, Brahma V; Mo, Alisa; Welsh, Claire S; Margolis, Russell L; Ross, Christopher A

    2012-02-01

    The objective of this study was to further explore the effect of CAG repeat length on the rate of clinical progression in patients with Huntington's disease. The dataset included records for 569 subjects followed prospectively at the Baltimore Huntington's Disease Center. Participants were seen for a mean of 7.1 visits, with a mean follow-up of 8.2 years. Subjects were evaluated using the Quantified Neurologic Examination and its Motor Impairment subscale, the Mini-Mental State Examination, and the Huntington's disease Activities of Daily Living Scale. By itself, CAG repeat length showed a statistically significant but small effect on the progression of all clinical measures. Contrary to our previous expectations, controlling for age of onset increased the correlation between CAG repeat length and progression of all variables by 69% to 159%. Graphical models further supported the idea that individuals with smaller triplet expansions experience a more gradual decline. CAG repeat length becomes an important determinant of clinical prognosis when accounting for age of onset. This suggests that the aging process itself influences clinical outcomes in Huntington's disease. Inconsistent results in prior studies examining CAG repeat length and progression may indeed reflect a lack of age adjustment.

  19. 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.

  20. 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.

  1. Clinical evaluation of IPS e.max Press all-ceramic crown and porcelain fused metal crown restorations%IPS e.max Press铸瓷与烤瓷全冠修复效果的临床观察

    Institute of Scientific and Technical Information of China (English)

    朱政; 高姗; 陈金华

    2012-01-01

    目的:评价比较IPS e.max Press铸瓷全冠、贵金属烤瓷全冠、镍铬合金烤瓷全冠的临床修复效果.方法:选择IPS e.max Press铸瓷全冠、贵金属烤瓷全冠、镍铬合金烤瓷全冠等3种材料修复上中切牙的患者各90例,参照美国公共卫生服务的相关标准对完成修复后即刻与12个月的修复体进行临床检查和相关评价,内容包括修复体颜色、牙龈边缘着色、继发龋、边缘密合度、牙龈健康状况等.结果:在修复体颜色与牙龈健康状况方面,IPS e.max Press铸瓷全冠与贵金属烤瓷全冠均显著优于镍铬合金烤瓷全冠(P<0.05);在牙龈边缘着色和边缘密合度方面,IPS e.max Press铸瓷全冠、贵金属烤瓷全冠与镍铬合金烤瓷全冠均存在显著性差异(P<0.05),IPS e.max Press铸瓷全冠最佳,贵金属烤瓷全冠次之;3组修复体均未发生继发龋.结论:IPSe.max Press铸瓷全冠修复的临床效果优良,贵金属烤瓷全冠次之,均优于镍铬合金烤瓷全冠.%Objective:To observe the clinical outcome of IPS e. max Press all-ceramic crown,gold alloy porcelain fused metal (PFM) crown and Ni-Cr alloy PFM crown restorations. Methods: Three groups of patients were treated with IPS e. max Press all-ceramic crown,gold alloy PFM crown or Ni-Cr alloy PFM crown restorations separately. The crown restorations were evaluated with the USPHS criteria for color match, marginal discoloration, secondary caries, marginal adaptation and gingival health immediately and after a period of 12 months. Results:The clinical outcome of both IPS e. max Press all-ceramic crown and gold alloy PFM crown restorations was better than Ni-Cr alloy PFM crown restorations for color match and gingival health. There was statistically significant difference in 3 groups for marginal discoloration and marginal adaptation, in which IPS e. max Press all-ceramic crown restoration was the best and gold alloy PFM crown restoration was better than Ni-Cr alloy

  2. 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.

  3. 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 crowns placed on tooth-neighboured abutments (n = 47), (5-year VCF-rate: 4.3%). In the present study, 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.

  4. Clinical value of core length in contemporary multicore prostate biopsy.

    Directory of Open Access Journals (Sweden)

    Sangchul Lee

    Full Text Available There is little data about the clinical value of core length for prostate biopsy (PBx. We investigated the clinical values of various clinicopathological biopsy-related parameters, including core length, in the contemporary multi-core PBx.Medical records of 5,243 consecutive patients who received PBx at our institution were reviewed. Among them, 3,479 patients with prostate-specific antigen (PSA ≤ 10 ng/ml level who received transrectal ultrasound (TRUS-guided multi (≥ 12-core PBx at our institution were analyzed for prostate cancer (PCa. Gleason score upgrading (GSU was analyzed in 339 patients who were diagnosed with low-risk PCa and received radical prostatectomy. Multivariate logistic regression analyses for PCa detection and prediction of GSU were performed.The mean age and PSA of the entire cohort were 63.5 years and 5.4 ng/ml, respectively. The overall cancer detection rate was 28.5%. There was no statistical difference in core length between patients diagnosed with PCa and those without PCa (16.1 ± 1.8 vs 16.1 ± 1.9 mm, P = 0.945. The core length was also not significantly different (16.4 ± 1.7 vs 16.4 ± 1.6mm, P = 0.889 between the GSU group and non-GSU group. Multivariate logistic regression analyses demonstrated that the core length of PBx did not affect PCa detection in TRUS-guided multi-core PBx (P = 0.923 and was not prognostic for GSU in patients with low-risk PCa (P = 0.356.In patients undergoing contemporary multi-core PBx, core length may not have significant impact on PCa detection and also GSU following radical prostatectomy among low-risk PCa group.

  5. Clinical success of implant-supported and tooth-implant-supported double crown-retained dentures.

    Science.gov (United States)

    Bernhart, Gunda; Koob, Andreas; Schmitter, Marc; Gabbert, Olaf; Stober, Thomas; Rammelsberg, Peter

    2012-08-01

    The objective of this retrospective study was to compare biological and technical complications of implant-supported and tooth-implant-supported double crown-retained dentures (DCRDs) with those of tooth-supported DCRDs. Sixty-three DCRDs were monitored. One study group included 16 prostheses with a combination of implants and natural teeth as double crowns (ti group), whereas in the second study group, 19 dentures were retained exclusively on implants (ii group); a third study group with 28 exclusively tooth-supported dentures served as controls (tt group). Tooth loss, implant failure, and technical complications (loss of retention of primary crown, abutment screw loosening, loss of facing, fracture of resin denture teeth and fracture of saddle resin) were analysed. During the observation period of 24 months, no implants or teeth were lost in the ti group and three technical complications were recorded. In the ii group, two implants were lost, two cases of peri-implantitis occurred and four technical complications were observed. In the tt group, two cases of tooth loss and seven technical complications were observed. At the time of the last examination, all prostheses of the ti group and the ii group were functional. Patients of these two study groups reported high satisfaction with both function and aesthetics with no significant difference between the two groups. Treatment with DCRDs showed comparable results in the three study groups. The 2-year results indicate that double crowns can be recommended for implant and combined tooth-implant-retained dentures.

  6. 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

  7. Flapless implant placement with crown lengthening procedure to correct crown height: a case report.

    Science.gov (United States)

    Jacobson, Nancy; Starr, Cliff

    2009-10-01

    Bone loss and soft tissue loss are common problems after tooth extraction and that can lead to excessive length of clinical crowns. This problem can be exacerbated by delaying implant placement after tooth extraction. In this case the opposite occurred. After flapless placement of a NobelDirect implant with immediate loading there was not enough vertical space for an esthetic restoration. Surgical crown lengthening was performed to create vertical space to place an esthetically pleasing restoration in harmony with the patient's existing dentition.

  8. CROWN LENGTHENING

    OpenAIRE

    2014-01-01

    2014 Latar Belakang: Penampilan jaringan gingiva disekitar gigi memegang peranan penting secara estetis. Abnormalitas dalam simetris dan kontur akan memiliki efek harmonisasi penampilan gigi-geligi. Prosedur yang dapat memberikan solusi untuk masalah estetik, periodontal dan restoratif ini adalah crown lengthening. Crown lengthening adalah prosedur bedah yang bertujuan dalam pengambilan dari jaringan periodontal untuk peningkatan panjang klinis ma...

  9. 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...

  10. [Analysis of ambulatory consultation length in medical clinics].

    Science.gov (United States)

    Outomuro, Delia; Actis, Andrea Mariel

    2013-03-01

    Planning a schedule for medical appointments in health services must be efficient and flexible, but also it has to meet the needs of patients, health professionals and non-medical staff. There are large differences in the opinión about the optimal duration to meet these objectives, across countries. In this paper we propose to perform a review of the literature to estímate the appropriate length ofa medical consultation in primary care, based on international standards. We conclude that managers of health systems should rethink the way they organize the agenda for medical appointments. Medical and bioethical reasons suggest assigning a lapse cióse to 20 minutes for consultations in medical clinics.

  11. 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.

  12. 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.

  13. 二氧化锆全瓷冠与镍铬合金烤瓷冠临床应用比较%Comparison of clinical application of zirconia all-ceramic crowns and Ni-Cr alloy crowns

    Institute of Scientific and Technical Information of China (English)

    周俊红

    2015-01-01

    Objective To observe and compare clinical effects of the zirconia all-ceramic crowns and Ni-Cr alloy crowns. Methods 80 patients of dentistry with 106 tooth in Department of Stomatology, Zhongguancun Hospital from February 2011 to February 2012 were selected, 40 patients with 56 tooth were treated with zirconia all-ceramic crowns and were chosen as zirconia all-ceramic crowns group; 40 patients with 50 tooth were treated with Ni-Cr alloy crowns and were chosen as Ni-Cr alloy crowns group. The items of restoration retainer, restoration contour, marginal accuracy, gingival situation, secondary caries between the two groups at repairmen time and 1 year after the repairmen were compared. Results①The two groups were all reached grade A in each indicator at repairmen time. The gingival tissue of grade A in zirconia all-ceramic crowns group [96.4% (54/56)] was higher than that in Ni-Cr alloy crowns group [86.0% (43/50)] 1 year after the repairmen, the difference was statistically significant (P0.05).②The differences of plaque index in the zirconia all-ceramic crowns group and the Ni-Cr alloy crowns group between 1 year after the repairmen [(0.92±0.36), (0.89±0.40)] and before the repairmen [(0.88±0.41), (0.88±0.41)] were all not statistically significant (P> 0.05). The differences of periodontal probing depth in the zirconia all-ceramic crowns group and the Ni-Cr alloy crowns group between 1 year after the repairmen [(2.41±0.20), (2.40±0.20) mm] and before the repairmen [(2.26±0.23), (2.28±0.21) mm] were all not statistically significant (P>0.05). Con-clusion The clinical effect of Zirconia all-ceramic crowns is better than Ni-Cr alloy crowns.%目的:观察比较镍铬合金烤瓷冠和二氧化锆全瓷冠的临床应用效果。方法选取中关村医院口腔科2011年2月~2012年2月治疗的牙科患者80例106颗患牙,其中40例患者共56颗牙采用二氧化锆全瓷冠修复,设为二氧化锆全瓷冠组;40例患者50颗牙采用镍铬合

  14. 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...

  15. 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.

  16. Clinical evaluation comparing the fit of all-ceramic crowns obtained from silicone and digital intraoral impressions

    NARCIS (Netherlands)

    Zarauz, C.; Valverde, A.; Martinez-Rus, F.; Hassan, B.; Pradies, G.

    2016-01-01

    Objectives The aim of this study is to compare the fit of all-ceramic crowns fabricated from conventional silicone impressions with the fit of all-ceramic crowns fabricated from intraoral digital impressions. Methods Twenty patients with 26 posterior teeth with a prosthetic demand were selected for

  17. Clinical Comparison of Zirconia All - ceramic Crown and Porcelain Fused to Metal Crown Restoration%二氧化锆全瓷冠与普通金属烤瓷冠修复的临床比较

    Institute of Scientific and Technical Information of China (English)

    张武

    2014-01-01

    目的:探讨临床使用二氧化锆全瓷冠与普通金属烤瓷冠修复的治疗效果对比。方法选择110例患者共146颗牙,随机分成两组,每组73颗牙。实验组采用二氧化锆全瓷冠进行修复;对照组采用普通金属烤瓷冠进行修复。按照美国公共健康协会制定标准评估修复情况。结果实验组全瓷冠的边缘完整性,牙龈状态,颜色等方面均表现良好,全瓷冠出现崩瓷占5.5%;对照组边缘完整性占93.15%,牙龈形态良好占95.9%,颜色表现良好占2.7%,冠出现崩瓷占8.2%。结论二氧化锆全瓷冠临床上的修复效果良好,值得临床推广使用。%Objective To comPare the theraPeutic effects of zirconia all - ceramic crown and Porcelain fused to metal crown restoration. Methods 110 Patients with a total of 146 teeth were randomly assigned into two grouPs with 73 teeth in each grouP. Zirconia all - ceramic crown restoration was used in exPerimental grouP,and Porcelain fused to metal crown restoration was used in the control grouP. Restorations were assessed according to the criteria established by United States Public Health Service(USPHS). Results Marginal integrity,gingival state and color were good in exPerimental grouP with 5. 5% fractured Porcelain. 93. 15% were good in marginal integrity,95. 9% were good in gin-gival state,2. 7% were good in color with 8. 2% fractured Porcelain in control grouP. Conclusion RePairing effects of zirconia all - ceramic crown are good,which is worth of clinical Promotion.

  18. 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.

  19. 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.

  20. Clinical Associations of Leukocyte Telomere Length in a Cohort of Repatriated Prisoners of War

    Science.gov (United States)

    2014-07-01

    1 RPW TELOMERE LENGTH 1. Title Page Clinical Associations of Leukocyte Telomere Length in a Cohort of Repatriated Prisoners of War Authors...Reprints will not be available from the authors Short Title: RPW Telomere Length Manuscript metrics: Word count for abstract - 200 Word count for...to 01-07-2014 4. TITLE AND SUBTITLE Clinical Associations of Leukocyte Telomere Length in a Cohort of Repatriated Prisoners of War 5a. CONTRACT

  1. Clinical study of zirconia all-ceramic crown and zirconia crown in molar fix prothesis%氧化锆全瓷冠与全锆冠后牙固定修复的临床研究

    Institute of Scientific and Technical Information of China (English)

    彭利辉; 钟爱喜; 潘小波; 刘光雪; 李荣婷

    2014-01-01

    目的比较氧化锆全瓷冠与全锆冠在后牙固定修复中的临床综合修复效果。方法36例后牙缺失需修复的患者,其中19例66颗牙行氧化锆全瓷冠桥修复,17例60颗牙行氧化锆全锆冠桥修复。追踪观察1~3年,由修复科医师对义齿的边缘适合性、牙龈健康情况、牙冠外形、色泽、是否崩瓷、破裂等进行评价。结果两组病例修复效果在所检查的指标中比较差异均无统计学意义( P>0.05)。结论氧化锆全瓷冠与全锆冠在边缘密合性、美观性及抗折强度方面,均能满足临床要求。但在合龈距离较短的病例中,全锆冠的修复更具优势。%Objective To compare the repairing effects between the zirconia all-ceramic crown bridge and zirconia bridge in aesthetics restoration of molars .Methods Thirty-six patients were restorated with the all-ceramic crown bridge(19 patients 66 molars) and zirconia ( bridge 17 patients 60 molars), followed up for 1 ~3 years, checked and appraised the marginal adaptation ,form,colour of the crowns ,the gingiva and crown fracture by one doc-tor.Results There was no statistically difference in the effects between the two kinds of restorations .Conclusion The two kinds of restoration can meet clinical needs in the marginal adaptation ,aesthetics and the flexural strength . The zirconia bridge is better in patients with shorter occlusogingival distance .

  2. 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

  3. Clinical success and survival of indirect resin composite crowns: results of a 3-year prospective study

    NARCIS (Netherlands)

    Jongsma, L.A.; Kleverlaan, C.J.; Feilzer, A.J.

    2012-01-01

    Objectives The aim of this study was to test the new resin composite "NECO" as a material for indirect restorations clinically. Methods Forty-five patients were selected, of which 12 men and 33 women, with a mean age of 53. A total of 91 post-canine indirect resin composite NECO (Heraeus Kulzer, Gmb

  4. 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.

  5. 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.

  6. 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.

  7. Clinical Study of Fiber Post CAD/CAM Zirconia Porcelain Crowns%纤维桩CAD/CAM氧化锆烤瓷冠临床应用研究

    Institute of Scientific and Technical Information of China (English)

    李剑; 陈国平; 江水清

    2013-01-01

    目的:追踪观察纤维桩CAD/CAM氧化锆烤瓷冠与传统的钴铬合金铸造桩钴铬合金烤瓷冠的临床效果,为评价纤维桩CAD/CAM氧化锆烤瓷冠的远期临床效果提供参考。方法:同期制作纤维桩CAD/CAM氧化锆烤瓷冠(A组),钴铬合金铸造桩钴铬合金烤瓷冠各21件(B组)。临床检查42件修复体边缘密合性,随访复查修复体的基牙继发龋和修复体的折裂、折断、脱落情况。结果:42件修复体平均随访3年。A组、B组边缘密合性分别为100%和88%(P0.05)。结论:纤维桩CAD/CAM氧化锆烤瓷冠边缘密合性好,能够达到传统金属固定桥的强度,满足临床应用要求。%Objective:Tracking observation of zirconia fiber pile CAD/CAM of PFM crown with traditional cobalt chromium alloy casting co-cr alloy porcelain crowns, clinical effect. Methods:At the same time production of zirconia fiber pile CAD/CAM porcelain crowns (group A), cobalt chromium alloy casting co-cr alloy porcelain crowns the 21 pieces (group B). And sex, clinical examination restoration margins follow-up review. Results: In group A and group B edge and sex were 100% and 88% respectively (P0.05). Conclusion:CAD/CAM zirconia fiber pile PFM crown edge and sex good, can achieve the strength of the traditional metal fixed bridge, satisfies the requirement of clinical application.

  8. 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.

  9. 氧化锆全瓷冠修复单个后牙的临床观察%Clinical evaluation of zirconia crowns for single posterior teeth

    Institute of Scientific and Technical Information of China (English)

    陈渊华; 孟翔峰; 俞青

    2014-01-01

    目的:观察CERECinLab计算机辅助设计和制造(CAD/CAM)的氧化锆全瓷冠修复复杂后牙的临床效果。方法对于242名需行单个后牙冠修复的患者,采用CERECinLabCAD/CAM设计制作二氧化锆全瓷修复体,共242件。分别在粘接完成时、6个月、12个月、24个月和36个月进行临床观察,采用改良的美国公共卫生署标准评估。结果采用χ2检验分析。结果观察期间有5名患者失访,对于剩余修复体观察发现,随着时间推移,修复体的成功率下降,在36个月时A级成功率在85%以上。结论CERECinLab制作的单个后牙的二氧化锆全瓷修复体,短期成功率良好。%Objective To observe and evaluate the clinical performance of zirconia crowns made by CEREC inLab com-puter aided design/computer aided manufacturing(CAD/CAM) for posterior teeth. Methods A total of 242 patients were implanted with zirconia crowns fabricated by CEREC inLab CAD/CAM. The crowns were evaluated by Modified US Public Health Service criteria at baseline, 6, 12, 24, and 36 months. The chi-square test was used to analyze the survival rate. Results All but five crowns were evaluated by an independent evaluator at baseline, 6, 12, 24, and 36 months. The survival rate de-clined with time. The A score percentage was above 85% at 36 months. Conclusion The single zirconia crowns fabricated by CEREC inLab CAD/CAM demonstrate satisfactory clinical performance during a short period.

  10. 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.

  11. Clinical effect of the CAD/CAM all-ceramic crowns on the anterior tooth restoration%计算机辅助设计和制造全瓷冠在前牙修复的临床效果

    Institute of Scientific and Technical Information of China (English)

    马慕兰; 张俭

    2013-01-01

    目的 比较计算机辅助设计和制造全瓷冠与钴铬合金烤瓷冠在前牙修复的临床效果.方法 采用计算机辅助设计和制造技术制作89件前牙二氧化锆全瓷冠,采用钴铬合金烤瓷冠制作67件前牙修复体,修复后1年复查,对边缘着色、龈缘密合度、修复体颜色、修复体周围龋、修复体折裂、牙龈健康情况进行评价.结果 在边缘着色、龈缘密合性、修复体颜色、牙龈健康状况方面差异有统计学意义(P<0.05),全瓷冠的临床效果优于钴铬合金烤瓷冠.结论 计算机辅助设计和制造全瓷冠的临床修复效果良好,是前牙修复的理想选择.%Objective To observe and compare the clinical effect of CAD/CAM all-ceramic crowns with cobalt-chromium alloy porcelain crowns in the restoration of anterior teeth.Methods Eighty-nine anterior teeth were restored with zirconia all-ceramic crowns,and 67 anterior teeth were restored with conventional cobalt-chromium alloy porcelain crowns.One year after the restoration,the marginal discoloration,change of marginal fit,color,caries around the crown,collapse porcelain and periodontal tissue heath of the two crowns were compared.Results The differences of the marginal discoloration,change of marginal fit,color,periodontal tissue heath between zirconia all-ceramic crowns and cobaltchromium alloy porcelain crowns was statistically significant (P < 0.1).The clinical effect of all-ceramic crowns was better than cobalt-chromium alloy porcelain crowns.Conclusion The clinical effect of CAD/CAM all-ceramic crowns was favourable in restoring anterior teeth.

  12. Clinical management of a complicated crown-root fracture using autogenous tooth fragment: A biological restorative approach

    Directory of Open Access Journals (Sweden)

    Vinaya Kumar Kulkarni

    2013-01-01

    Full Text Available Trauma resulting in crown-root fracture is one of the most challenging fracture types. However, biologic width involvement should be carefully evaluated. Reattachment of tooth fragment to a fractured tooth remains as the treatment of choice because of its simplicity, natural esthetics, and conservation of tooth structure. The reattachment procedure using composite resin should be considered if the subgingival fracture can be exposed to provide isolation. This report presents a case of complicated crown-root fracture of permanent maxillay left central incisor, involving the biologic width in a 10-year-old girl. The traumatized tooth was treated endodontically. Access to the subgingival margins was gained by orthodontic extrusion followed by gingivectomy. The fractured fragment was reattached using bonding system and composite resin.

  13. 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.

  14. 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

  15. CAD/CAM全锆冠与钴铬烤瓷冠修复的临床短期疗效观察%A short term clinical evaluation of CAD/CAM zirconia crown and porcelain Co-Cr crown in restoration of teeth

    Institute of Scientific and Technical Information of China (English)

    刘思璇; 王亮; 王丁

    2016-01-01

    Objective To evaluate the short term clinical performance of crowns, respectively constructed with CAD/CAM zirconia and porcelain Co-Cr.Methods Eighty defected teeth were selected, and then restored with CAD/CAM zirconia and porcelain crowns after endodontically treatment. Each crown was reviewed in six, twelve months after its placement.Results All the crowns were intact, while the color matching and the gingival condition in zirconia crowns were better than the other group.Conclusion The clinical performance of the CAD/CAM zirconia crowns is optimal.%目的:评价氧化锆全瓷冠与钴铬烤瓷冠修复牙体缺损的短期临床效果。方法本研究选取80例牙体缺损的患牙,于牙体治疗后分别采用氧化锆全瓷冠,钴铬烤瓷冠进行修复,在修复后的6、12个月时,观察其临床修复效果。结果观察期间,两组修复体外形均保持良好,而氧化锆全瓷冠在美观效果、牙龈健康状况方面优于钴铬烤瓷冠。结论氧化锆全瓷冠具有更好的临床修复效果。

  16. 树脂短桩结合透明冠修复上颌乳前牙残冠的临床观察%Clinical observation of resin short post combined with strip crown to restore the residual crown of maxillary deciduous anterior teeth

    Institute of Scientific and Technical Information of China (English)

    李文敏; 闫长山; 秦帅华

    2016-01-01

    Objective To observe the clinical effect of resin short post combined with strip crown to restore the residual crown of maxillary deciduous anterior teeth. Methods Select 75 residual crown of maxillary deciduous anterior teeth which were removed all of dental caries and accepted root canal therapy, and then treat them by short post core restoration with composite resin, combined with strip crown to restore the shape. Results Reexamination after 4 years showed 71 cases succeed and 4 cases failed, the success rate is 94.7%. Conclusion The method of the composite resin short pile combined with transparent crown is used to restore the residual crown of maxillary deciduous anterior teeth is reliable and suitable for clinical application.%目的:观察树脂短桩结合透明冠的方式修复上颌乳前牙残冠的临床效果。方法:选择75颗乳上前牙残冠,去净龋坏并行根管充填后,用复合树脂做短桩核修复,再结合透明冠恢复外形。结果:4年后复查,成功71颗,失败4颗,成功率94.7%。结论:采用复合树脂短桩联合透明冠的方式修复上颌乳前牙残冠,效果可靠,适合临床推广使用。

  17. 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.

  18. Analysis of causes of upper incisor metal crown root fracture%分析上切牙金属桩冠根折的原因

    Institute of Scientific and Technical Information of China (English)

    叶莲妹

    2014-01-01

    ABSTRACT:Objective a variety of reasons incisor metal post crown root fracture analysis. Methods in recent yearscollected in our hospital for treatment of upper incisor crown root fracture and 400 cases wereunable to retain metal post crown and root, according to the analysis of root pile is therelationship, and the root length and crown restoration way. Results on metal post crown root fracture length of incisors and the metal pile in the bone related, when the probability ofoccurrence of length rootin the total length of the alveolar bone 1/2, single crown root fracture occurrence rate is higher than the crown crown root fracture. ensure the clinical crown length is greater than or equal tothe pile height should not only . Conclusion Metal pile nuclear crown in the restoration of maxillary incisor teeth, but also make the pile in the bone length is greater than the total length of root inthe alveolar bone 1/2, also want to consider is the single crown or linked crown.%目的:分析上切牙金属桩冠根折的各种原因。方法收集我院近几年治疗的因上切牙桩冠因根折而无法保留金属桩冠及牙根的400例病例,分析根据是根桩与牙根长度关系、冠修复方式。结果上切牙金属桩冠根折与金属桩在骨内的长度有关,当长度<牙根在牙槽骨总长度的1/2时发生牙折的几率要高于>牙根在牙槽骨总长度的1/2时,单个桩冠根折发生率要高于联冠桩冠根折。结论金属桩核冠在修复上切牙时不仅要保证桩的长度≥临床冠的高度,还要使桩在骨内的长度大于牙根在牙槽骨总长度的1/2,同时也要考虑是单冠修复还是联冠修复。

  19. Step-length variability in minimally disabled women with multiple sclerosis or clinically isolated syndrome.

    Science.gov (United States)

    Flegel, Melanie; Knox, Katherine; Nickel, Darren

    2012-01-01

    Gait is one of the most frequently impaired bodily functions in multiple sclerosis (MS). Determining abnormal parameters of gait in early MS could influence MS treatment and rehabilitation. The purpose of this study was to determine whether increased step-length variability could be detected in minimally disabled patients with MS or clinically isolated syndrome (CIS) using a sensored walkway gait analysis system. Nine participants with MS/CIS and nine age- and gender-matched controls were recruited for this study. MS/CIS participants underwent a neurologic examination, and all participants completed a screening interview. Each participant completed three walks at a self-selected pace and three walks at a brisk pace across the GAITRite walkway (MAP/CIR Inc, Havertown, PA). Mean values for step-length variability, step length, and velocity were calculated for each participant's self-selected and brisk trials. Independent t tests were used to compare MS/CIS participants with controls, and effect sizes were calculated. Step-length variability in the left leg at the self-selected pace was found to be greater in participants with MS/CIS than in controls, although no significant differences were found in velocity or step length. Step-length variability measurement shows promise in detecting subtle gait dysfunction. Larger, prospective studies exploring step-length variability may determine its clinical viability for detecting subtle gait dysfunction and could lead to improved prognostication of disability progression in MS.

  20. 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.

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

    OpenAIRE

    2015-01-01

    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 ...

  2. 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。

  3. 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.

  4. Success of Hall technique crowns questioned.

    Science.gov (United States)

    Nainar, S M Hashim

    2012-01-01

    Hall technique is a method of providing stainless steel crowns for primary molars without tooth preparation and requires no local anesthesia. Literature review showed inconclusive evidence and therefore this technique should not be used in clinical practice.

  5. CAD/CAM玻璃陶瓷全冠在后牙义齿修复中的运用%Clinical application of CAD/CAM all ceramic crown in the restoration of the posterior teeth

    Institute of Scientific and Technical Information of China (English)

    胡媛媛; 许琼莉; 周娟; 冷卫东; 陈永吉; 牛玉明

    2015-01-01

    Objective:To investigate the clinical use of CAD/CAM all ceramic crown in the restoration of the poste-rior teeth. Method:Thirty-five patients with forty-seven teeth of residual crown were selected and restored with CAD/CAM all ceramic crown after completely root canal therapy. Result:With 3 to 18 months following study,The retention、marginal adaptation and periodontal tissue of the dental prosthetic restoration of forty-five teeth were satisfactory ,one crowns with occlusion flaws,one crown failed for crown loose. Conclusion:The CAD/CAM all ceramic crown in the restoration for the posterior teeth can provide better effect of retention and esthetics.%目的:研究CAD/CAM全瓷冠在后牙义齿修复中的应用。方法:35例患者47个后牙经完善根管治疗后,使用CAD/CAM氧化锆全冠修复。结果:随访3~18个月,45个牙冠修复体的固位、边缘密合度、牙周状况均良好,1个冠咬合面出现隐裂,1个牙冠修复体出现松动。结论:CAD/CAM氧化锆全冠在后牙义齿修复中能够提供较好的固位及美学效果。

  6. 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

  7. Relationship between the length of the uterine cavity and clinical pregnancy rates after in vitro fertilization or intracytoplasmic sperm injection.

    Science.gov (United States)

    Chun, Sang Sik; Chung, Min Ji; Chong, Gun Oh; Park, Kee Sang; Lee, Taek Hoo

    2010-02-01

    In this prospective clinical study involving 354 IVF-intracytoplasmic sperm injection cycles, we determined the influence of the length of the uterine cavity on clinical pregnancy rates. Our data showed that clinical pregnancy and implantation rates are associated positively with an increased length of the uterine cavity.

  8. 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 .

  9. Clinical observation of the metal-ceramic crowns with shoulder porcelain of anterior teeth%肩台瓷金瓷冠在前牙修复中的临床效果观察

    Institute of Scientific and Technical Information of China (English)

    唐颖; 袁剑鸣; 潘峰

    2013-01-01

      Objective To observe the prosthetic effects of the metal-ceramic crowns with shoulder porcelain of anterior teeth clinically. Methods Forty-two units of metal-ceramic crowns with shoulder porcelain, forty-four u-nits Ni-Cr based porcelain-fuse-metal crowns were observed after one year through clinical methods. Results There were some differences between the two groups in color match, contour, marginal integrity and health of gum. But the difference between the two groups had no statistic significance. The differences of marginal integrity and marginal discoloration between metal-ceramic crowns with shoulder porcelain and Ni-Cr based porcelain-fuse-metal crowns had high statistic significance. Conclusion Using metal-ceramic crowns with shoulder porcelain could progress the esthetics in anterior teeth.%  目的分析肩台瓷金瓷冠在前牙修复中的临床效果。方法根据纳入标准分别对42颗肩台瓷金瓷冠、44颗镍铬合金烤瓷冠修复1年后的临床效果进行观察对比,评价其结果。结果2组间在颜色、外形、边缘密合性、牙龈健康方面有差异但无统计学意义。在牙龈灰线、边缘变色方面有差异,且差异有统计学意义。结论肩台瓷金瓷冠在前牙修复中有较好的美观效果。

  10. 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.

  11. Clinical efficacy of Tenax glass fiber posts on restoration of anterior residual crowns and roots%Tenax玻璃纤维桩修复前牙残冠残根的临床疗效观察

    Institute of Scientific and Technical Information of China (English)

    刘朝明; 曹峰

    2012-01-01

    Objective To investigate the effect of repairing anterior residual crowns and roots with glass fiber posts plus resin cores and all ceramic crowns. Methods 120 teeth with residual crowns and roots from 86 patients were selected and randomly divided into treatment group and control group. 64 teeth from 43 patients in the treatment group were treated with glass fiber posts plus resin cores and all-ceramic crowns, while 56 teeth from 43 patients in the control group were treated with cast metal posts and cores and Ni-Cr PFM crowns. Clinical standards for PFM crown restoration from California Dental Association were adopted to evaluate the efficacy. Results The success rate of the treatment group was 96.5% .while the success rate of the control group was 85%. Conclusions Glass fiber posts and all ceramic crowns are ideal materials to restore the anterior residual crowns and roots.%目的 探讨玻璃纤维桩树脂核加全瓷冠修复前牙残冠残根的临床疗效.方法 选择86例120颗前牙残冠残根,随机分为治疗组43例64颗和对照组43例56颗,治疗组患者采用玻璃纤维桩树脂核加全瓷冠修复,对照组患者采用铸造金属桩核加镍铬烤瓷冠修复.采用美国加州牙科协会的烤瓷冠修复临床标准进行疗效评价.结果 治疗组成功率为96.8%,对照组成功率为83.9%.结论 玻璃纤维桩和全瓷冠是修复前牙残冠残根的理想材料.

  12. 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

  13. Factors influencing the clinical expression of intermediate CAG repeat length mutations of the Huntington's disease gene.

    Science.gov (United States)

    Panegyres, Peter K; Shu, Chen-Chun; Chen, Huei-Yang; Paulsen, Jane S

    2015-02-01

    Our aim is to elucidate the clinical variables associated with the development of manifest HD in patients with intermediate CAG repeat lengths. 2,167 participants were seen throughout 44 research sites in the United States, Canada or Australia over a five-year natural history observational study (2006-2011) (Trial # NCT00313495). The Chi-square test and a generalised linear model were used to examine the differences in demographics and cognitive tests among three groups of CAG repeat length. The mixed model was then used to examine the time effect on cognitive assessments by CAG groups. No patient with CAG repeat length 27-35 developed manifest HD, whereas three patients with 36-39 did. Total motor score, maximal chorea score and maximal dystonia score were significantly different at baseline (p CAG 36-39; those with an associated university degree or higher education were less frequently diagnosed as manifest HD (OR 0.10, 95 % CI 0.02-0.54, p = 0.007). Age, smoking and lower education achievement were found to be significantly associated with higher odds of manifest HD in patients with intermediate CAG repeat length mutations.

  14. 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.

  15. 种植后CEREC Ⅲ全瓷单冠修复的临床研究%Clinical study of CEREC Ⅲ all ceramic crown restorations for implant

    Institute of Scientific and Technical Information of China (English)

    张建英; 赵晓华; 贾丽红; 马艳美

    2012-01-01

    目的:评价种植术后CEREC Ⅲ全瓷单冠修复1年的临床效果.方法:选取2010年1月~ 2010年6月来解放军第264医院数字口腔中心就诊采用CEREC Ⅲ全瓷单冠修复的患者22例.修复后追踪观察1年,按照改良的USPHS标准进行临床评价.结果:各项指标均达到了B标准或以上,其中颜色匹配令人满意,达到A标准者为95.45%.结论:种植后CEREC Ⅲ全瓷单冠修复具有较好的临床效果,值得推广.%Objective To evaluate the practicality and performance of CEREC III all ceramic crown restorations for implant after one year of clinical service. Methods Twenty-two patients with 22 all ceramic crown restorations were involved in the study.These crowns were made from 2010.1 ~2010.6.After one year, the clinical performance of the restorations evaluated by examiners using modified USPHS criteria. Results Crown restorations scored B using modified USPHS criteria. Most satisfactory was color match problem that achieve 95.45% of A criteria. Conclusion It was satisfactory for CEREC III all ceramic crown restorations for implant.

  16. 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.

  17. The relationship between CAG repeat length and clinical progression in Huntington's disease.

    Science.gov (United States)

    Ravina, Bernard; Romer, Megan; Constantinescu, Radu; Biglan, Kevin; Brocht, Alicia; Kieburtz, Karl; Shoulson, Ira; McDermott, Michael P

    2008-07-15

    The objective of this study was to examine the relationship between CAG repeat length (CAGn) and clinical progression in patients with Huntington's disease (HD). There are conflicting reports about the relationship between CAGn and clinical progression of HD. We conducted an analysis of data from the Coenzyme Q10 and Remacemide Evaluation in Huntington's Disease (CARE-HD) clinical trial. We modeled progression over 30 months on the Unified Huntington's Disease Rating Scale (UHDRS) and supplemental neuropsychological and behavioral tests using multiple linear regression. Mean subject age was 47.9 +/- 10.5 years and mean CAGn was 45.0 +/- 4.1. Multiple linear regression revealed statistically significant associations between CAGn and worsening on several motor, cognitive, and functional outcomes, but not behavioral outcomes. Many effects were clinically important; 10 additional CAG repeats were associated with an 81% increase in progression on the Independence Scale. These associations were not observed in the absence of age adjustment. Age at the time of assessment confounds the association between CAGn and progression. Adjusting for age shows that longer CAGn is associated with greater clinical progression of HD. This finding may account for the variable results from previous studies examining CAGn and progression. Adjusting for CAGn may be important for clinical trials.

  18. 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)

  19. Observation on clinical application value of all-ceramic crown of glass ifber post and resin core for residual crown and residual root repair of anterior teeth%玻璃纤维桩树脂核全瓷冠在前牙残冠及残根修复中的临床应用价值探讨

    Institute of Scientific and Technical Information of China (English)

    李伟; 赵国廷; 徐革英

    2014-01-01

    Objective To observe the clinical application value and effect of all-ceramic crown of glass fiber post and resin core for residual crown and residual root repair of anterior teeth. Method 106 cases with residual crown and residual root of anterior teeth treated in our hospital from April 2010 to March 2012 were selected, and the patients received repair after root canal therapy. The patients were divided into two groups according to repair modes, observation group and control group. Observation group received repair of all-ceramic crown of glass ifber post and resin core, and control group received repair of cast metal post-core and baked porcelain crown. The repair effect of two groups was compared and observed. Result After following up for two years, the success rate and satisfactory degree of observation group was evidently higher than that of control group, and the expulsion rate and odontagma rate of restoration was lower than that of control group (P<0.05), which had statical signiifcance. Conclusion Applying all-ceramic crown of glass ifber post and resin core to all-ceramic crown of glass ifber post and resin core for residual crown and residual root repair of anterior teeth not only has good retention, good color and appearance maintenance, and has little stimulation on the surrounding tissues, but also can effectively reduce detachment and fracture of restoration, which evidently improves the success rate of repair and satisfactory degree of patients, which has ideal clinical application value.%目的:探讨在前牙残冠、残根修复中使用玻璃纤维桩树脂核与全瓷冠的临床应用效果及价值。方法选取本院2010年4月至2012年3月收治的前牙残冠、残根患者106例,根管治疗后修复,并根据修复方式分为观察组与对照组,观察组患者使用玻璃纤维桩树脂核与全瓷冠修复,对照组患者使用铸造金属桩核与烤瓷冠或全瓷冠修复,对比观察两

  20. Clinical results of α- Ceramic 88 gold alloy for metal-ceramic-crowns%傲丹特烤瓷用金合金临床试验观察

    Institute of Scientific and Technical Information of China (English)

    李阳; 王新知

    2012-01-01

    Objective To evaluate the clinical effect of metal -ceramic-crowns made of α- Ceramic 88 gold alloy. Methods Fifty-one patients with defected incisors or premolars were restored with α— Ceramic 88 gold alloy PFMs. Fifty cases as control were restored with HERA Bio N gold alloy PFMs. Before cementation, the fitness of the crowns was examined using a polyether indicator paste. The thickness of the polyether films at marginal sites was measured by the GALILEEO EZ image measuring system. All patients were followed up for 6 tol2 months. The clinical index was recorded at the time of delivery and return visit, including casting defects of the copings , marginal polishing performance , porcelain fracture,visual estimation of the marginal fitness ,mucosal allergy and adverse reactions. Results The α-Ceramic 88 gold alloy group showed as good clinical performance and biosafety as the control group . The mean thickness of the polyether films was not significantly different between the two alloys. Conclusion The clinical performance of α— Ceramic 88 gold alloy was as good as the HERA Bio N gold and fulfilled the requirement of clinical application .%目的 评价国产傲丹特α- Ceramic 88烤瓷用金合金的临床应用效果.方法 选取志愿患者101名,对每名患者的1颗缺损前牙或双尖牙进行烤瓷全冠修复,其中试验组51名,采用傲丹特α- Ceramic 88烤瓷用金合金;对照组50名,采用古莎-贺利氏Bio N烤瓷用金合金.两组均制取基底冠与牙体预备体之间的聚醚密合性检测膜,用GALILEO EZ612-300影像测量系统检测聚醚膜厚度,对比两组金合金烤瓷全冠的密合性.在患者试戴基底冠、初次戴牙、戴牙6~12个月复查时,记录各项临床观察指标:烤瓷冠内冠有无铸造缺陷、临床探查内冠边缘密合性、边缘抛光性、有无口腔黏膜过敏反应、牙周组织有无红肿,有无不良事件.结果 试验组及对照组临床观察各项指标均合格,应用

  1. 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.

  2. 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

  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. 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.

  5. 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...

  6. 安氏Ⅱ1错牙合临床牙冠中心高度的测量分析%Study on the center height of the clinical crown in classⅡ1 malocclusion

    Institute of Scientific and Technical Information of China (English)

    徐佳瑛; 马超; 金雪梅

    2016-01-01

    目的:比较正常牙合与安氏Ⅱ1类错牙合模型上下颌临床牙冠中心高度,为安氏Ⅱ1类错牙合矫治设计提供参考。方法:收集正常牙合,安氏Ⅱ1类错牙合模型各50例,用数显游标卡尺分别测量各组模型的临床牙冠高度并计算出临床牙冠中心高度,进行对比分析。结果:安氏Ⅱ1类错牙合组上下颌临床牙冠高度及临床牙冠中心高度均较正常牙合组小,大部分测量值间的差异有统计学意义。结论:安氏Ⅱ1类错牙合畸形患者正畸治疗中应注意托槽定位,以期获得更完美的咬合状态。%Objective:To compare the center height of the clinical crown of Class Ⅱ1 and normal occlusion casts in order to provide reference for the diagnosis and treatment of Class Ⅱ1 malocclusion. Method:50 casts of normal occlusion and Class Ⅱ1 malocclusion were selected as the control group and the experimental group , respectively. The height of the clinical crown and the center height of the clinical crown were measured with a digital vernier caliper and analyzed. R e-sult: The height of the clinical crowns and the center height of the clinical crown of both the maxillary and mandibular arches in class Ⅱ1 malocclusion were smaller than those in the normal occlusion. Most differences were statistically signif-icant. Conclusion: During treating classⅡ1 malocclusion patients, attention should be paid to the correct positioning of brackets for achieving the best occluding relation after treatment.

  7. 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。

  8. 玻璃纤维桩联合氧化锆全瓷冠在残冠残根修复中的临床分析%Clinical application of glass fiber post in combination with a zirconia-ceramic crown in the restoration of residual roots and crowns

    Institute of Scientific and Technical Information of China (English)

    裘松波; 卢礼; 徐昌会; 张萍; 周燕; 张纲

    2011-01-01

    Objective To study the clinical effect of glass fiber post and resin core in combination with a zirconia-ceramic crown in the restoration of residual roots and crowns. Methods Forty-eight patients were enrolled in the study. A total of 65 teeth (26 anterior and 39 posterior with 22 abutment teeth; 18 residual roots and 47 residual crowns) were restored with glass fiber post and resin core in combination with a zirconia ceramic crown. After 6 months to 2 years, all patients were examined and the restoration effect was evaluated. Rtestults In all cases, 3 post debondings occurred after the restoration of residual roots (failure rate 4.62% ), in which 2 cases were restored after re-treatment and 1 case was withdrawn. No fracture of zirconia-ceramic crown was observed. No root or post fracture was observed clinically or on radiographs. No apical or periodontal shadow was observed on radiographs, and no secondary dental caries of tooth neck was found. Conclusion The application of glass fiber post in combination with a zirconia-ceramic crown is feasible in metal-free restora tion of residual roots and crowns.%目的 探讨玻璃纤维桩和树脂核联合氧化锆全瓷冠在残冠残根修复中的临床效果.方法 以玻璃纤维桩和树脂核联合氧化锆全瓷冠修复残冠残根病例48例,共65颗牙(前牙26颗,后牙39颗,其中作为桥基牙的有22颗;残根18颗,残冠47颗).于修复完成6个月至2年,对全部临床病例进行随访、检查和评估.结果 3颗残根修复后纤维桩脱落,失败率为4.62%,其中2颗经再治疗后有效,另1颗被放弃;其余病例氧化锆全瓷冠保持完整,纤维桩无脱落、折断;X线片示牙根和纤维桩无折断,无牙周和根尖的阴影,牙颈部无继发龋.结论 应用玻璃纤维桩树脂核联合氧化锆全瓷冠修复残冠残根,达到了无金属修复的临床要求,是一种较理想的修复方法.

  9. 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.

  10. [The method of esthetic crown restoration with composite resin jacket crown in primary molars].

    Science.gov (United States)

    Doi, K; Shibui, N; Suda, M; Uehara, M; Karibe, H; Kondou, K

    1990-10-01

    The term "esthetics" has recently been also used in the dental field, and a field called esthetic dentistry is increasingly being noted. The number of not only adult but also pediatric patients who visit for treatment aiming at esthetic recovery is being increased. Inpedodontics, composite resin of the coronal color is generally used in the restoration of deciduous incisors. However, the method using metal crowns for the deciduous teeth is used for the deciduous molars at present. We applied a composite resin jacket crown to the deciduous molar in a way similar to that of esthetic crown restoration for the anterior teeth. The surgical procedure before crown preparation varied slightly according to the presence or absence of pulpal treatment of vital teeth and with non-vital teeth, but the application was performed as follows: 1) Desensitization of pulp, pulpal treatment and core construction. 2) Preparation of crown. 3) Selection, trial set and occlusal equilibration of a metal crown for the deciduous tooth. 4) Precision impression with a silicone impression material. 5) Removal of the metal crown for the deciduous tooth from the impression material. 6) Making of an under-cut to the abutment tooth on the buccal lingual side. 7) Filling of the impression with chemical polymerization resin. 8) Application of pressure in the oral cavity. 9) Adjustment of edge and crown forms. Thus, the preparation method for the composite resin jacket crown was relatively simple. Since this surgery, the patient has been followed up for 1 year and 6 months, and no specifically troublesome points have been observed clinically. The patient and her parents are satisfied with the results.(ABSTRACT TRUNCATED AT 250 WORDS)

  11. Lava无饰瓷二氧化锆冠修复后牙的临床疗效初探%Preliminary study of clinical effect of Lava full-contour CAD/CAM zirconia crowns for posterior teeth

    Institute of Scientific and Technical Information of China (English)

    陈磊; 孙强; 廉云敏

    2014-01-01

    Objective To evaluate clinical effects of Lava full-contour CAD/CAM zirconia crowns for posterior teeth. Methods Sixty two patients participated in the present study. Seventy three Lava full-contour CAD/CAM zirconia crowns were made on posterior teeth. All of the crowns were cemented using resin cement. Evaluating the cases of crown fracture, color of the crown, contour, marginal fitness, secondary caries, marginal color change at two weeks, three months, half a year, one year, two years and three years following delivery. Results Lava full-contour zirconia crowns demonstrated good fracture resistance, and no fracture were found. All of 73 crowns were grouped into A-level in color, contour, marginal fitness, secondary caries. There were only 5 crowns suffered from marginal color change. Conclusion The full-contour CAD/CAM zirconia crowns are good restorations for posterior teeth defect. It contributes to avoid the incidence of veneering porcelain fracture, and conserve more residual tooth structure.%目的:评价Lava无饰瓷二氧化锆冠修复后牙牙体缺损的临床疗效。方法在我院口腔修复科门诊选择62例后牙需全冠修复的患者,采用Lava系统制作73颗无饰瓷二氧化锆冠,运用树脂水门汀粘固全冠。修复后,在2周、6个月、1年、2年、3年复诊进行临床检查。评价指标如下:冠的折裂情况、颜色、解剖形态、边缘密合度、冠边缘有无龋、冠边缘着色。结果在73颗无饰瓷二氧化锆冠修复体中,只有5颗冠的边缘着色(C级),采用二氧化锆口内抛光套装成功去除色素沉着。所有无饰瓷二氧化锆冠在破损折裂情况、冠颜色、解剖形态、冠边缘的密合度、冠边缘有无龋均被评为A级。结论采用Lava无饰瓷二氧化锆冠能成功修复后牙牙体缺损,同时避免了饰面瓷的崩瓷问题,此外减少了牙体预备量,保留了更多的残余牙体组织。

  12. 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.

  13. 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.

  14. Restoration of the Severely Decayed Tooth Using Crown Lengthening with Simultaneous Tooth-Preparation

    OpenAIRE

    2010-01-01

    This clinical case describes a treatment approach that combines, in a single appointment, a crown lengthening procedure and the final crown preparation for the restoration of a severely decayed tooth. This approach allows for a more accurate placement of the crown margin in relation to the bone crest while reducing treatment time.

  15. Restoration of the severely decayed tooth using crown lengthening with simultaneous tooth-preparation.

    Science.gov (United States)

    Park, Jun-Beom

    2010-04-01

    This clinical case describes a treatment approach that combines, in a single appointment, a crown lengthening procedure and the final crown preparation for the restoration of a severely decayed tooth. This approach allows for a more accurate placement of the crown margin in relation to the bone crest while reducing treatment time.

  16. 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.

  17. 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。

  18. Clinical Observation on CAD/CAM Zirconia Ceramic Crowns in 50 Cases of the Implant Prosthesis%CAD/CAM氧化锆全瓷冠在50例种植修复中的临床观察

    Institute of Scientific and Technical Information of China (English)

    康振中; 唐吉飞

    2013-01-01

    目的 探讨CAD/CAM氧化锆全瓷冠在50例种植修复中的临床效果.方法 选取种植术后患者50例,共72颗缺失牙.采用CAD/CAM氧化锆全瓷冠修复,随访3a,了解患者全瓷冠完整情况和冠周情况.结果 经3a随访观察发现,50例患者72颗修复体中,2颗修复体周围有轻微炎症,治疗后痊愈.3颗后牙修复体瓷面破损,其余修复体均正常,失败率为4.2%.结论 采用CAD/CAM氧化锆全瓷冠进行种植修复可取得良好效果.%Objective To evaluate the clinical effect of CAD/CAM zirconia ceramic crowns in 50 cases of prosthesis.Method 50 cases with 72 missing teeth after planting operation were fixed with CAD/CAM allceramic crowns.There were 72 missing teeth.All patients were followed up 3 years,in which the intactness of zirconium porcelain crown and the status of gingival prosthesis were checked.Results 72 Missing teeth were fixed among 50 cases.It was found after the follow-up for 3 years that peripheral surfaces of 2 teeth were slightly inflammatory and recovered after treatment.The surfaces of 3 prostheses were damaged and the others were normal.The failure rate was 4.2%.Conclusion Adopting CAD/CAM zirconia ceramic crowns to repair implants teeth can achieve a better therapeutic effect.

  19. 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

  20. 桩核冠在前牙美容性修复中的临床应用%Clinical application of post-core crown in anterior teeth aesthetical restoration

    Institute of Scientific and Technical Information of China (English)

    陈勃; 郑春玉; 刘建军; 方继荣; 杨玲

    2010-01-01

    Objective To investigate the clinical status of post-core crown in anterior teeth aesthetical restoration and to observe its effect. Methods 126 cases of anterior teeth in patients with mild deformity,restored with post-core crown after informed consent meanwhile conducted clinical follow-up observation. Results In addition to 2 cases of disease after root canal treatment, 1 incisal and labial surface of porcelain fracture, other cases achieved desired results in the way of self-satisfaction,clinical efficacy and x-ray observation and periapical films. Conclusion Post-core crown in anterior aesthetical restoration has a unique position and clinical efficacy.%目的 探讨桩核冠在前牙美容性修复治疗中的临床地位,并观察其疗效.方法 对126例前牙区轻度畸形的患者,在知情同意的情况下行桩核冠修复,并进行临床随访观察.结果 除2例发生根管治疗后疾病,1例切端及唇面崩瓷以外,其他病例在自我满意度、临床效果及X线根尖片观察等方面均达到理想预期效果.结论 桩核冠修复技术在前牙美容性修复治疗中有独特的临床地位和疗效.

  1. [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.

  2. 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.

  3. 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.

  4. 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.

  5. Clinical effects of two kinds of porcelain fused to metal crown%两种不同烤瓷冠修复的疗效比较

    Institute of Scientific and Technical Information of China (English)

    薛晋徽

    2012-01-01

    目的 比较全瓷冠修复和金瓷冠修复的优缺点,为患者提供更好的修复方式.方法 选择进行烤瓷全冠修复的患者共计修复义齿258颗,分为全瓷冠组98颗和金属烤瓷冠组160颗,进行基牙预备,取模,比色,送制作.结果 经过2年随访观察,258颗冠修复中有15颗出现了不同程度的牙龈边缘着色,均为金瓷冠修复体,10颗患者对修复体颜色不满意.8颗修复体出现崩瓷现象.结论 金瓷冠修复体金属内冠薄,硬度大,比重轻,抗压强度大,在高温下反复烧烤也很少发生挠曲变形,适合于跨度大的长桥体修复.全瓷冠因其无金属结构,具有良好的光传播和光反射功能,可再现自然牙半透明深度和色深度,层次感强,适合前牙修复.%Objective To compare advantages and disadvantages of ceramic crown and porcelain fused to metal(PFM),provide better rehabilitation ways for patients.Methods 258 porcelains were,divided into two groups:ceramic crown group 98 and metal ceramic crowns group 160,for preparation of abutment,modulus,colorimetric,feed production.Results Follow-up observation for 2 years,the 15 crowns of all appeared the gingival edge coloring with different degree,are PFM,10 patients were not satisfied with the color of restorations.8 repair body porcelain.Conclusion Inner crown metal of PFM is thin and light,with high hardness and compressive strength.It rarely occur deformation since repeated the barbecue at high temperatures,so suitable for large span bridge restoration.Ceramic crown because of no metal structure,good light transmission and light reflecting function,can reproduce the natural teeth translucent depth and color depth,strong sense of hierarchy,suitable for the repair of anterior teeth.

  6. 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.

  7. 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.

  8. 玻璃纤维桩与氧化锆全瓷冠修复磨牙临床分析%Clinical analysis of glass fiber piles and Zirconium all-ceramic crowns repair molar cases

    Institute of Scientific and Technical Information of China (English)

    刘红; 宋志红

    2012-01-01

    Objective To evaluate the clinical application of glass fiber post and resin core combined with zirconia all -ceramic crowns in the restoration of the molar. Methods Totally 70 teeth from 58 patients were restored by glass fiber post and resin core. All the patients were observed, examined and evaluated after 3 months to 2 years of the restoration. Results Totally 2 restoration of the residual root fell off, the failure rate is 3. 4%. One of the two was restored by glass fiber post and the other was restored by implant. Other fiber post have no fell off or broken. Zirconia all - ceramic crowns was preserved perfectly with good marginal adaption. Conclusions Molar restoration with fiber post and resin core combined with zirconia all - ceramic crowns is an ideal clinical method.%目的 探讨玻璃纤维桩树脂核联合氧化锆全瓷冠修复磨牙的临床效果.方法 玻璃纤维桩树脂核联合氧化锆全瓷冠修复磨牙58例,共70颗牙.修复完成3个月至2年,对全部病例进行随访,检查和评估.结果 2颗残根修复后纤维桩脱落,失败率为3.4%,其中1颗再次桩冠修复,一颗拔除后种植修复.其余病例氧化锆全瓷冠保持完整,边缘密合,纤维桩无脱落、折断.结论 纤维桩树脂核联合氧化锆全瓷冠修复磨牙,临床效果好,是一种较理想的修复方法.

  9. 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.

  10. Retrospective Analysis of 200 Anterior All-ceramic Crown Long-term Clinical Effects%200个前牙全瓷冠远期临床效果的回顾性分析

    Institute of Scientific and Technical Information of China (English)

    衡超; 乔梦婷

    2014-01-01

    Objective This study evaluated the long -term clinical effects of 200 feldspathic all-ceramic crown res-toration after 1 to 5 years, in order to provide clinical reference.Methods According to the United States Public Health include 8 indices, such as completeness, abrasion, color satisfaction, edge staining, marginal adaption, secondary caries, dentine hypersensitivity symptoms and gingival index (GI).We used the lifetime table to collect the statistics of the survival rate of porcelain crowns from 1 to 5 years.Results All-ceramic crowns from 1 to 5 years survival rate were 99.5%, 98.0%, 96.4%, 95.2%and 93.9%.Conclusions The long-term clinical effect of all -ceramic crowns is good.%目的:评价完成修复1~5年的200个长石质全瓷冠的远期临床效果,以期为临床效果仅为参考。方法对完成修复1~5年的200个前牙全瓷冠进行修复,参照改良美国公共健康协会( United States Public Health Society ,USPHS)评价标准对全瓷冠的修复体完整度、修复体磨耗、颜色满意度、边缘染色、边缘适合性、继发龋、牙本质敏感症状及牙龈指数(gingival index, GI)8项指标进行评估,寿命表统计烤瓷全冠1~5年存留率。结果全瓷冠1~5年存留率分别为99.5%、98.0%、96.4%、95.2%、93.9%。结论全瓷冠修复技术的远期临床效果良好。

  11. 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

  12. 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

  13. 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.

  14. 218 例残冠用金属烤瓷冠修复效果的临床评价%Evaluation on clinical effect of ceramic alloy crown on treating residual tooth in 218 patients

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Objective: To evaluate the forward clinical effect of ceramic alloy crown on treating residual tooth. Methods: After the treating residual teeth of 218 patients by ceramic alloy crown, to observed the clinical effect for two to seven years after treatment. Results: The rate of forward success was 98% in all of the 218 patients. Conclusion: It is suggest that many different factors that influence forward successful treatment to avoid failing.%目的:评价用金属烤瓷冠修复残冠的临床效果。方法:对 218 例残冠病人用金属烤瓷冠修复治疗后,经过 2~7a 的随访复查,以观察该项治疗的效果。结果:本组病例修复成功率为 98%。讨论:分析了影响修复成功的各种因素,以便进一步完善该项修复治疗。

  15. 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 ...

  16. 石英纤维桩与二氧化锆全瓷冠修复前牙缺损的临床研究%Clinical research of quartz fiber post and zirconia crown on restoration of anterior tooth defect

    Institute of Scientific and Technical Information of China (English)

    周丽华; 何赐丁; 陈蕾

    2013-01-01

    Objective To investigate the clinical effect of quartz fiber post and zirconia crown on restoration of anterior tooth defect. Methods 63 anterior teeth from 52 patients after root canal therapy were restored with quartz fiber posts and zirconia crowns. The effect was evaluated after 1 year, 2 years and 3 years respectively. Results There was no difference after 3 years.One post core got lossen, one crown was lost. The other tooth reached at a rank A in all six aspects among 3 years.Their color matches with the nature teeth excellently The success rate was 96.8%. Conclusion The effect of on restoration of anterior tooth defect is ideal.%目的:探讨石英纤维桩及二氧化锆全瓷冠在前牙缺损修复中的应用.方法:选择52例患者的63颗缺损前牙,用石英纤维桩及二氧化锆全瓷冠修复,分别于1、2、3年复查.结果:修复后3年,1例出现桩核松动,1例出现冠脱落,其余患者6项评价指标均达到A级,颜色匹配无差异,成功率达96.8%.结论:石英纤维桩结合二氧化锆全瓷冠在前牙缺损修复中的临床效果较为理想.

  17. 前牙美学修复中氧化锆全瓷冠的临床应用分析%Analysis of the Clinical Application of the Front Teeth Aesthetic Repair Zirconia All Porcelain Crown

    Institute of Scientific and Technical Information of China (English)

    刘方宇; 丁存善

    2015-01-01

    目的:探讨氧化锆全瓷冠修复体的临床应用注意事项及其美学性、稳定性和生物相容性。方法:选取本院口腔科收治的59例患者(患牙78颗),行CAD/CAM氧化锆全瓷冠修复患牙,随访一年,通过对全瓷冠色彩在口内的匹配度、有无破损和崩瓷、牙龈的健康状况以及与邻牙的接触关系来研究其美学性能、生物性能及稳定性。结果:59例患者对修复的效果整体满意。结论:通过CAD/CAM技术完成的氧化锆全瓷冠在前牙美学修复中增加了全冠的美学效果,提升了冠修复的稳定性和生物相容性。%Objective:To investigate clinical application,aesthetics,stability and bio-compatibility of zirconia all-ceramic crowns.Method:Computeraided design and computer aided manufacturing(CAD/CAM)techniqueswere used to make zirconia all-ceramic crowns for 78 teeth on 59 patients.After one year follow-up,the esthetics,stability bio-compatibility were investigated by examining oral adaptability of crow color,breakage ratio,losing ratio and gingival health..Result:The effect of the 59 patients to repair the overall satisfaction. Conclusion:The esthetics,stability and bio-compatibility of zirconia-veneered crowns were enhanced by CAD/CAM technique.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. CAD/CAM锆瓷冠在后牙种植修复中的临床应用%Clinical application of CAD/CAM zirconia ceramic crowns in the implants repair of back teeth

    Institute of Scientific and Technical Information of China (English)

    郭敏; 刘林

    2012-01-01

    目的 探讨CAD/CAM锆瓷冠在后牙种植体修复中的临床应用.方法 选取种植术后患者30例,采用CAD/CAM 全瓷冠修复,随访2年,检查患者锆瓷冠完整情况及修复体情况.结果 30例患者共修复缺失牙43颗,经2年随访观察发现,1颗磨牙面瓷破损,其余修复体均正常,失败率为2.3%,修复体形态、表面质地,边缘适合性能、修复体颜色等级等修复效果满意.结论 采用CAD/CAM锆瓷冠进行后牙种植修复,种植体周围无不良刺激,咀嚼效果良好,稳定不脱落,舒适美观,患者可取得良好的修复效果.%Objective To investigate the clinical application of CAD/CAM zirconia ceramic crowns in the implants repair of back teeth. Methods 30 cases of patients after planting operation were repaired with CAD/CAM all-ceramic crowns. All patients were followed up 2 years, and the intactness of zirconium porcelain crown and the status of gingival prosthesis were checked. Results 43 missing tooth were repaired among 30 cases of patients, after 2 years of follow-up, porcelain damage of molar surface in one case was observed and the rest prosthesis were normal, the failure rate was 2.3%; repairing effect of shape, surface texture, marginal adaptation, performance and color grade were satisfactory. Conclusion Adopting CAD/CAM zirconia ceramic crowns to repair back teeth implants shows no negative stimulus around the implants, which has good chewing function and stability and is comfortable and beautiful, thus achieves good repair outcomes.

  3. 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.

  4. Infant orthopedics in UCLP: effect on feeding, weight, and length: a randomized clinical trial (Dutchcleft).

    NARCIS (Netherlands)

    Prahl, C.; Kuijpers-Jagtman, A.M.; Hof, M.A. van 't; Prahl-Andersen, B.

    2005-01-01

    OBJECTIVE: To study the effects of infant orthopedics (IO) on feeding, weight, and length. DESIGN: Prospective two-arm randomized controlled trial in three academic Cleft Palate Centers. Treatment allocation was concealed and performed by means of a computerized balanced allocation method. SETTING:

  5. Influence of position and length of uterus on implantation and clinical pregnancy rates in IVF and embryo transfer treatment cycles.

    Science.gov (United States)

    Egbase, P E; Al-Sharhan, M; Grudzinskas, J G

    2000-09-01

    In a prospective study of 807 consecutive women shown to have an apparently normal uterus after hysterosalpingography, hysteroscopy or pelvic ultrasonography prior to IVF or intracytoplasmic sperm injection (ICSI) and embryo transfer, the position and length of the uterine cavity was measured routinely at a pre-treatment mock transfer procedure. The apparent length of the uterine cavity was 9 cm in 85 women (group 3). The uterus was noted to be retroverted in 38. 2% (308) women. The embryo transfer catheter was advanced to 5 mm from the uterine fundus based on the previously determined cavity length in all the embryo transfer procedures at 48 h after oocyte collection. Implantation and clinical pregnancy rates were not significantly different with respect to position of the uterus, difficulties encountered in passage of the catheter, mean age of the women, aetiology or duration of infertility or embryology events. An apparently greater cavity length was seen in older and/or parous women, but the difference was not statistically significant. Although the highest implantation and clinical pregnancy rates were seen in women with a cavity length of 7-9 cm (group 2) the differences were not statistically significant: group 1, 18.9 and 36. 7%; group 2, 21.0 and 46.5%; and group 3, 17.3 and 32.9% respectively. The incidence of ectopic pregnancy per reported clinical pregnancy was highest in group 1 women, being 14.9% (7/47) in comparison with group 2 (1.8%, 5/276) and group 3 (0%, 0/27) (P: size of the uterus is a critical factor in the aetiology of ectopic pregnancy in IVF/ICSI-embryo transfer.

  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. [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.

  8. 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

  9. Clinical effects comparison of zirconia all-ce-ramic crown and zirconia crown in molar fix prosthesis%全锆冠与氧化锆全瓷冠在后牙固定修复中的临床效果比较

    Institute of Scientific and Technical Information of China (English)

    孙庆忠

    2014-01-01

    目的:对牙缺失患者分别进行全锆冠与氧化锆全瓷冠后牙固定修复,比较分析全锆冠与氧化锆全瓷冠用于修复的临床治疗效果.方法:选择本院2013-01/2014-02收治的56例因后牙缺失而需要修复的患者,根据牙齿缺损程度分为对照组和实验组,分别采用不同材料进行固定修复.其中实验组29例90颗后牙进行氧化锆全瓷冠桥修复,对照组27例87颗后牙进行氧化锆全锆冠桥修复,并统一追踪观察1~3年,通过对义齿的边缘适合性、牙冠外形,牙龈健康情况,是否崩瓷、色泽、破裂等情况进行对比评价.结果:对所有检查的指标进行比较发现,两组病例修复效果均无显著性差异(P>0.05),无统计学意义.结论:在边缘美观性、密合性及抗折强度方面,采用氧化锆全锆冠与氧化锆全瓷冠桥修复均能够满足临床的要求.%AIM:To compare the repairing effects between the zirconia all-ceramic crown bridge and zirconia bridge in aesthetics restoration of molars.METHODS:82 cases were divided into two groups according to their damage of teeth,test group and con-trol group.The test group and control group were restorated with the all-ceramic crown bridge (29 patients,90 molars)and zirco-nia bridge (27 patients,87 molars),followed up for 1 ~3 years, checked and appraised the form,marginal adaptation,color of the crowns,the gingiva and crown fracture.RESULTS:After in-spection,there was no statistically difference in the effects be-tween the two kinds of restorations (P <0.05 ).CONCLU-SION:The two kinds of restoration can both meet clinical needs in the aesthetics,marginal adaptation and the flexural strength.

  10. 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.

  11. 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.

  12. Failure modes and fracture origins of porcelain veneers on bilayer dental crowns.

    Science.gov (United States)

    Liu, Yihong; Liu, Guanghua; Wang, Yong; Shen, James Zhijian; Feng, Hailan

    2014-01-01

    The aims of this study were to determine the fracture origins and crack paths in the porcelain of clinically failed bilayer ceramic restorations and to reveal the correlation between the porcelain failures and material properties. Three clinically failed crowns of each material (bilayer zirconia crowns, galvano-ceramic crowns, and porcelain-fused-to-metal crowns) were collected and underwent failure analysis. The fractures found in porcelain veneers showed several characteristics including wear, Hertzian cone crack, chipping off, and delamination. The results indicated that the fracture origins and features of the porcelain in bilayer ceramic restorations might be affected by the rigidity of core materials and thickness of copings.

  13. 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.)

  14. Esthetic restoration of infra-occluded retained primary mandibular incisors with all-ceramic crowns in adult dentition.

    Science.gov (United States)

    Hsu, Kuang-Wei; Shen, Yu-Fu

    2004-12-01

    The prevalence of hypodontia is reported to be between 1.5% to 10% in the permanent dentition. In the anterior teeth, maxillary lateral incisors and mandibular central incisors are the most frequently involved teeth. This causes esthetic problems for the patient. Several reports have focused on restoration of retained maxillary primary anterior teeth, but none have described restoration of retained mandibular primary incisors. This clinical report describes the restoration of infra-occluded retained primary mandibular central incisors of a 17 year-old girl diagnosed with hypodontia. All-ceramic crowns made with computer-aided design/ computer-aided manufacturing technology were used to restore the teeth incisally and interproximally. Due to a relatively short root length and inadequate crown-root ratio, the primary mandibular central incisors were splinted and adjusted to distribute the protrusive force evenly across the maxillary and mandibular incisors. Functional and esthetic results were achieved.

  15. 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.

  16. IPSe.max CAD全瓷冠修复的短期临床评价%Clinical study of short-term restorative effects of IPS e. max CAD ceramic crown

    Institute of Scientific and Technical Information of China (English)

    翟家彬; 黄丽娟; 俞青

    2015-01-01

    目的:对IPS e. max CAD 全瓷冠近期修复效果进行观察和评价。方法共选取469例542颗前、后牙IPS e. max CAD 全瓷冠修复体,修复3~12个月后,按照美国加州牙科协会(CDA)制定的全瓷修复临床评定标准进行修复体评估。结果97.2%的修复体保持完整,未出现破裂、崩瓷、脱落、基牙冠折等并发症,患者满意度较高。结论 IPS e. max CAD 全瓷修复体的近期修复效果良好。%Objective To study and evaluate the short-term restorative effects of IPS e. max CAD ceramic crown. Methods 469 patients with 542 restorations were selected and the satisfactory degree of the patients was investigated. The restorative effect was evalua-ted after 3-12 months. Result The satisfactory rate of IPS e. max CAD full ceramic restorations was 97. 2%,without porcelain frac-ture,loss of crown or abutment broken. Conclusion The short-term clinical behavior of IPS e. max CAD all ceramic restorations is en-couraging.

  17. 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.

  18. 牙冠延长术修复残根残冠的疗效分析%Analysis of the clinical effects of corwn lengthening on residual root and crown repair

    Institute of Scientific and Technical Information of China (English)

    李月华; 李尚峰

    2015-01-01

    目的:探讨牙冠延长术在残根残冠修复中的方法及临床效果.方法:将2011年6月-2014年8月治疗的71例(76颗)残根残冠修复患者,按随机数字表法分为观察组37例(41颗)和对照组34例(35颗).观察组行牙冠延长术,对照组行牙龈切除术,比较两组患者的临床治疗效果.结果:治疗效果观察组满意35颗,欠佳4颗,总有效率95.1%;对照组满意19颗,欠佳10颗,总有效率82.9%,满意率及总有效率组间比较,差异均有统计学意义(P<0.05).治疗后观察组龈沟出血指数(SBI)、牙周袋深度(PD)指标改善均优于对照组;差异均有统计学意义(P<0.05).结论:牙冠延长术用于残根、残冠的修复,避免了活动修复体所致不便及固定修复体引起的邻牙损伤,修复时间短,修复体稳定,且有利于保持修复牙周围组织健康、口腔美观及功能修复,临床效果满意.临床应严格适应证的选择,提高治疗效果.%Objective To explore the methods and clinical effect of corwn lengthening on residual root and crown repair. Methods Divided the 71 patients(76 teeth)with residual root and crown into observation group and control group by random number table,for observation group with 37 patients (41 teeth)and control group with 34 patients(35 teeth).To the patients in observation group treated with corwn lengthening and to the patients in control group treated with gingivectomy,the patients clinical therapeutic effects were compared. Results The therapeutic effects were satisfied in 35 teeth,and poor in 4 teeth in observation group,the total effective rate was 95.1%.In control group,The therapeutic effect was satisfied in 19 teeth,and poor in 10 teeth,the total effective rate was 82.9%, there was a significant difference on satisfaction rate and total effective rate between the two groups( P<0.05).The SBI and PD improve condition in observation group were superior to that in control group after the treatment,there was a significant

  19. Raspberry Crown Borer [Pennisetia marginata

    OpenAIRE

    Alston, Diane

    2015-01-01

    This fact sheet described raspberry crown borer, a pest that attacks raspberry plants in northern Utah, causing cane-wilt and death. It includes life history, host injury, monitoring and thresholds, and management techniques.

  20. Overdenture dengan Pegangan Telescopic Crown

    Directory of Open Access Journals (Sweden)

    Pambudi Santoso

    2014-06-01

    Full Text Available Kaitan presisi merupakan alat retensi mekanis yang menghubungkan antara satu atau lebih pegangan gigi tiruan, yang bertujuan untuk menambah retensi dan/atau stabilisasi. Kaitan presisi dapat digunakan secara luas pada gigi tiruan cekat, gigi tiruan sebagian lepasan, overdenture, implant untuk retensi overdenture, dan protesa maksilo fasial. Overdenture dengan kaitan presisi dapat membantu dalam pembagian beban kunyah, meminimalkan trauma pada gigi pegangan dan jaringan lunak, meminimalkan resorbsi tulang, dan meningkatkan estetik dan pengucapan suara. Salah satu jenis dari kaitan presisi adalah telescopic crown, terdiri dari 2 macam mahkota, yaitu mahkota primer yang melekat secara permanen pada gigi penyangga, dan mahkota sekunder yang melekat pada gigi tiruan. Tujuan pemaparan kasus ini adalah untuk memberikan informasi tentang rehabilitasi pasien edentulous sebagian rahang atas dengan telescopic crown..  Pasien wanita berusia 45 tahun datang ke klinik prostodonsia RSGM Prof.Soedomo dengan keluhan ingin dibuatkan gigi tiruan. Pasien kehilangan gigi 11 12 15 16 17 21 22 24 25 26 dan 27 yang diindikasikan untuk pembuatan overdenture gigi tiruan sebagian lepasan (GTS kerangka logam dengan pegangan telescopic crown pada gigi 13 dan 14 dengan sistem parallel-sided crown. Tahap-tahap pembuatan telescopic crown yaitu mencetak model study dengan catatan gigit pendahuluan. Perawatan saluran dilakukan pada akar gigi 13, dilanjutkan pemasangan pasak fiber serta rewalling dinding bukal. Gigi 13 dan 14 dilakukan preparasi mahkota penuh, dilanjutkan dengan pencetakan model kerja untuk coping primer dan kerangka logam dengan metode double impression. Coping primer disementasi pada gigi penyangga, dilanjutkan pasang coba coping sekunder beserta kerangka logam. Selanjutnya dilakukan pencatatan gigit, pencetakan model kerja, penyusunan gigi dan pasang coba penyusunan gigi pada pasien. Prosedur dilanjutkan dengan proses di laboratorium, serta insersi pada

  1. 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.

  2. Nutritional status influences the length of stay and clinical outcomes in hospitalized patients in internal medicine wards

    Directory of Open Access Journals (Sweden)

    Ana Manuela Ordoñez

    2013-08-01

    Full Text Available Objective: The aim of this study was to investigate the relationship between the nutritional status (NS and clinical outcome and length of stay (LOS among patients admitted to the internal medicine ward. Methods: This is a retrospective observational study performed with the data of clinical patients collected during a one year period. The NS was assessed using: subjective global assessment (SGA, body mass index (BMI, triceps skinfold thickness (TST, muscle arm circumference (MAC and combined tools. Statistical analysis was performed with a confidence interval of 95% (p < 0.05. For categories comparison the chi-square test was used. To examine the association between length of stay and variables related to the NS Mann-Whitney and Kruskal-Wallis tests was used with multiple comparisons. Results: 396 patients were included in the study, 42.2% were over 60 years of age, what was associated with the presence of hypertension (p < 0.001, diabetes mellitus (p = 0.003 and required diet with modifications consistency (p = 0.003. According to combined diagnostic tools, 45.7% of patients were malnourished. Decreased food intake (p = 0.01, malnutrition according to SGA (p = 0.02 and MAC (p = 0.03 were associated with increased mortality. Patients with tertiary level of care (p = 0.01, decreased food intake (p = 0.001, who died (p = 0.004 and diagnosed with malnutrition by SGA (p = 0.001 and by the combined tools (p = 0.001 had a longer LOS. Conclusions: Patients who were malnourished by SGA and who presented decrease food intake at admission had longer LOS and poorer clinical outcomes (highest number of deaths. The diagnosis of malnutrition by MAC was also related to higher mortality.

  3. 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.

  4. Resorption of Lateral Incisors during Canine Eruption: Two Clinical Cases with Focus on Root Lengths and Heredity

    Directory of Open Access Journals (Sweden)

    Mostafa Zargham

    2016-01-01

    Full Text Available Introduction: It is well-known that pressure from orthodontic appliance can provoke root resorption in dentitions with short roots. The purpose of this case report is to demonstrate two clinical cases with focus on root length in dentitions exposed due to pressure from erupting teeth. This is a pilot study aimed to improve diagnostics for avoiding the resorption of lateral maxillary incisors by pressure from erupting canines. Case Report: The first reported case is of a girl who was 11 years and 7 months old when radiographs showed severe resorption of the lateral incisors, along with malformed central incisors and short roots. The intraoral photos demonstrated light crowding in the maxilla. The orthopantomogram of the girl’s mother demonstrated several short roots. The second reported case is of a girl who was 9 years and 5 months old when radiographs demonstrated nearly complete resorption on her lateral incisor roots, extremely short roots in the central incisors, and short roots. The intraoral photos demonstrated light crowding in the maxilla. The orthopantomogram of the girl’s mother demonstrated extremely short roots in general. Conclusion: This pilot study indicates that short root length in general and abnormal incisor morphology are phenotypic traits that were characteristic for both girls who presented with severe lateral incisor resorption due to erupting canines. Furthermore, short roots were also demonstrated in the mothers. Accordingly, short root length in general could be a phenotypic trait, which should be diagnosed early for preventing severe resorption of lateral incisors during canine eruption.

  5. 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...

  6. 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.

  7. 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.

  8. 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 .

  9. Amplified fragment length polymorphism of Streptococcus suis strains correlates with their profile of virulence-associated genes and clinical background.

    Science.gov (United States)

    Rehm, Thomas; Baums, Christoph G; Strommenger, Birgit; Beyerbach, Martin; Valentin-Weigand, Peter; Goethe, Ralph

    2007-01-01

    Amplified fragment length polymorphism (AFLP) typing was applied to 116 Streptococcus suis isolates with different clinical backgrounds (invasive/pneumonia/carrier/human) and with known profiles of virulence-associated genes (cps1, -2, -7 and -9, as well as mrp, epf and sly). A dendrogram was generated that allowed identification of two clusters (A and C) with different subclusters (A1, A2, C1 and C2) and two heterogeneous groups of strains (B and D). For comparison, three strains from each AFLP subcluster and group were subjected to multilocus sequence typing (MLST) analysis. The closest relationship and lowest diversity were found for patterns clustering within AFLP subcluster A1, which corresponded with sequence type (ST) complex 1. Strains within subcluster A1 were mainly invasive cps1 and mrp+ epf+ (or epf*) sly+ cps2+ strains of porcine or human origin. A new finding of this study was the clustering of invasive mrp* cps9 isolates within subcluster A2. MLST analysis suggested that A2 correlates with a single ST complex (ST87). In contrast to A1 and A2, subclusters C1 and C2 contained mainly pneumonia isolates of genotype cps7 or cps2 and epf- sly-. In conclusion, this study demonstrates that AFLP allows identification of clusters of S. suis strains with clinical relevance.

  10. 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.

  11. 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.

  12. 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....

  13. 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.

  14. 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...

  15. Eleven-Year Retrospective Survival Study of 275 Veneered Lithium Disilicate Single Crowns.

    Science.gov (United States)

    Simeone, Piero; Gracis, Stefano

    2015-01-01

    The aim of the present clinical retrospective study was to evaluate the long-term survival and clinical performance of veneered lithium disilicate single restorations in anterior and posterior areas after up to 11 years. Following a rigid protocol, 275 lithium disilicate single crowns (35 IPS Empress II and 240 e.max Press) were cemented over 11 years, in 106 patients, using an adhesive technique; of these 106 were anterior (38.5%) and 169 posterior (61.5%) teeth. Teeth receiving endodontic therapy and composite reconstruction (50%) and teeth with preexisting metalceramic crowns, called prosthetic retreatments (PR; 65%), were included as well. Of the 106 patients enrolled in the study, 25 (23.5%) were diagnosed with bruxism habits, and 7 of these patients (6.6% of all patients) received full-mouth single lithium disilicate restorations (FMR). The exclusion criteria for this retrospective clinical study were: monolithic lithium disilicate crowns, teeth with cast post and cores, implant-supported all-ceramic crowns, active periodontitis, and/or poor oral hygiene. Clinical reevaluation was performed by the clinicians who prepared and luted them during maintenance appointments between January 2012 and October 2013. Number of restoration failures and characteristics of failures were recorded. Marginal adaptation and marginal discoloration were evaluated based on the Cvar-Ryge criteria. The overall cumulative survival rate was 98.2%. The failures recorded were the result of either mechanical failure or debonding. Five crowns failed mechanically-three because of chipping and two because of core fracture-and were replaced. None of the failed crowns was associated with the bruxers with FMR. A total of 15 crowns debonded (5.5% of all crowns); however, 11 belonged to the same patient who had endodontically treated and reconstructed abutments. In this retrospective clinical evaluation of up to 132 months, veneered lithium disilicate single crowns had a low failure rate.

  16. 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。

  17. 纤维桩与金属桩行桩核冠修复的临床疗效观察%The Clinical Effect Observation of Fiber Post and Metal Post on Post-Crown Restoration

    Institute of Scientific and Technical Information of China (English)

    薛雯; 李娟

    2013-01-01

    Objective To compare the clinical effects of fiber post-retained and metal post-retained in crown restorations.Methods One hundred and five patients (130 teeth) admitted to Zhengzhou First People's Hospital from March 2009 to March 2010 were included in this study.130 endodontally treated teeth were divided into two groups (trial group of 55 patients,control group of 50 patients)randomly and each group consisted of 65 teeth.The trial group teeth were restored with fiber post-resin core and porcelain crown and the control group teeth were treated with cast metal post-core and porcelain crown.The teeth were clinically examined regularly for two years and then compared.Results One fiber post dislocated 1 year after restoration and the success rate was 98.5%.Two gingival inflammation cases and one root fracture case occurred among the metal post group in 1 year after restoration,and the success rate was 95.4%.There was no statistically significant difference between the two groups(x2 =0.256,P > 0.05).Two years after restoration,three teeth of fiber post group failed,all because of the post dislocation and the success rate was 95.4%.Seven teeth including three gingival inflammation,three root fracture and one post dislocation of metal post group failed,and the success rate was 89.2%.There was no statistically significant difference between the two groups (x2 =1.73,P > 0.05).Conclusion Fiber post-retained restoration can be used clinically instead of metal post-restained restoration.These restoration methods can be chosen based on individual conditions in clinical application.%目的 比较纤维桩与金属桩在桩核冠修复治疗中的疗效.方法 选择2009年3月至2010年3月在郑州市第一人民医院口腔科行桩核冠修复的患者105例(130颗患牙),随机分为两组:试验组55例(65颗患牙)采用纤维桩+树脂核联合烤瓷冠修复,对照组50例(65颗患牙)采用铸造金属桩核联合烤瓷冠修复.修复后随访观察2年,

  18. Multidisciplinary Management of Complicated Crown-Root Fracture of an Anterior Tooth Undergoing Apexification

    OpenAIRE

    Merve Mese; Merve Akcay; Bilal Yasa; Huseyin Akcay

    2015-01-01

    The purpose of this case report was to present the multidisciplinary management of a subgingival crown-root fracture of a patient undergoing apexification treatment. A 12-year-old male patient was referred to the pediatric dentistry clinic with an extensive tooth fracture of the right permanent maxillary lateral incisor. Clinical and radiographic examinations revealed the presence of a complicated crown-root fracture, which had elongated to the buccal subgingival area. The dental history disc...

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. Identification of genes involved in the response of banana to crown rot disease.

    Science.gov (United States)

    Lassois, Ludivine; Frettinger, Patrick; de Lapeyre de Bellaire, Luc; Lepoivre, Philippe; Jijakli, Haissam

    2011-01-01

    Variations in banana susceptibility to crown rot disease have been observed but the molecular mechanisms underlying these quantitative host-pathogen relationships are still unknown. This study was designed to compare gene expression between crowns of banana fruit showing a high susceptibility (S(+)) and crowns showing a low susceptibility (S(-)) to the disease. Comparisons were performed at two situation times: i) between crowns (S(+) and S(-)) collected 1 h before inoculation and ii) between crowns (S+ and S-) collected 13 days after inoculation. Gene expression comparisons were performed with cDNA-amplified fragment length polymorphism (AFLP) and results were confirmed by real-time reverse-transcription polymerase chain reaction. Among genes identified as differentially expressed between S(+) and S(-) crowns, two were involved in signal transduction, three in proteolytic machinery, two had similarity to pathogenesis-related protein 14, one to a CCR4-associated factor protein, and one to a cellulose synthase. Paradoxically, the overexpression of the cellulose synthase gene was associated with banana showing a high susceptibility in both pre- and post-inoculation situations. Finally, the cDNA-AFLP identified a gene that seems to be associated with the quantitative banana responses to crown rot disease; this gene encodes a dopamine-β-monooxygenase, which is involved in the catecholamine pathway. To our knowledge, this work is the first to address both pre- and post-infection gene expression with the same host-pathogen combination and distinct susceptibility levels.

  4. 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.

  5. [Sunrise gold foil jacket crown].

    Science.gov (United States)

    Lecardonnel, A

    1989-09-01

    This technique permits the preparation of ceramic jacket crowns made on Sunrise laminated precious metal alloy. The Sunrise foil is gold-colored, made of 99% of precious metals and is 50 microns thick. The die is prepared in order to display a moderate and regular undercut beyond the cervical limit. The margin will be underlined with a red pencil. The Sunrise foil is cut according to predetermined templates. Then the foil is applied without burnishing, according to the technique of jacket crowns on platinum foil only by finger pressure. The double folding on closure is preferably done distally or mesially. Then, the metal base is disinserted, sandblasted with 100 microns aluminum oxide, replaced on its die, and placed in a rubber casing before being placed in the isostatic press, to be subjected to a pressure of 2,000 TSI (14 kg par cm2). Sunrise's orange color reinforces rather subtetly the overall color, making these reconstructions particularly esthetic. The color of the Sunrise metal does not require, therefore a too thick opaque. Any ceramic intended to be fired on a metal base, may be used in respecting its firing protocol. Sunrise, as any other technique of this type, require a careful preparation with a shoulder that has a rounded gingivoaxial line angle. Bridges may be built on the "thimbles" crowns, fitted on Sunrise cores, the pontics being made as a ceramo-metal framework.

  6. Evaluation of sampling strategies to estimate crown biomass

    Directory of Open Access Journals (Sweden)

    Krishna P Poudel

    2015-01-01

    Full Text Available Background Depending on tree and site characteristics crown biomass accounts for a significant portion of the total aboveground biomass in the tree. Crown biomass estimation is useful for different purposes including evaluating the economic feasibility of crown utilization for energy production or forest products, fuel load assessments and fire management strategies, and wildfire modeling. However, crown biomass is difficult to predict because of the variability within and among species and sites. Thus the allometric equations used for predicting crown biomass should be based on data collected with precise and unbiased sampling strategies. In this study, we evaluate the performance different sampling strategies to estimate crown biomass and to evaluate the effect of sample size in estimating crown biomass. Methods Using data collected from 20 destructively sampled trees, we evaluated 11 different sampling strategies using six evaluation statistics: bias, relative bias, root mean square error (RMSE, relative RMSE, amount of biomass sampled, and relative biomass sampled. We also evaluated the performance of the selected sampling strategies when different numbers of branches (3, 6, 9, and 12 are selected from each tree. Tree specific log linear model with branch diameter and branch length as covariates was used to obtain individual branch biomass. Results Compared to all other methods stratified sampling with probability proportional to size estimation technique produced better results when three or six branches per tree were sampled. However, the systematic sampling with ratio estimation technique was the best when at least nine branches per tree were sampled. Under the stratified sampling strategy, selecting unequal number of branches per stratum produced approximately similar results to simple random sampling, but it further decreased RMSE when information on branch diameter is used in the design and estimation phases. Conclusions Use of

  7. Biological restoration: A 4/5 crown

    Directory of Open Access Journals (Sweden)

    Monize Ferreira Figueiredo de Carvalho

    2013-01-01

    Full Text Available Dental caries is one of the most prevalent conditions in humans; the purpose of restorative dentistry is to recreate the anatomy of the affected tooth thus the use of fragments from natural teeth as an effective restorative method. A maxillary first premolar left was prepared for an inverted 4/5 crown due to involvement of the vestibular face, after prepared received an allogeneic collage with similar color and dimension. Follow-up after 12 months indicated a stable restoration. Clinically, the site was without signs of caries, migration of the fragment or marginal infiltration. Biological restoration is a viable alternative for reestablishing function and esthetics to damaged/decayed teeth and therefore, biological restoration as an alternative to other restorative options.

  8. Partial Pulpotomy with BioAggregate in Complicated Crown Fractures: Three Case Reports.

    Science.gov (United States)

    Tuloglu, Nuray; Bayrak, Sule

    2016-01-01

    This report describes three cases of complicated crown fractures treated with partial pulpotomy using BioAggregate. Three maxillary permanent central incisors with complicated crown fracture were treated by partial pulpotomy using BioAggregate and reviewed clinically and radiographically for 24 months. Throughout this period, there was no spontaneous pain, periapical radiolucency, and coronal discoloration; the pulp was observed to be vital. Based on these findings, it was concluded that BioAggregate can be used in partial pulpotomy treatment of complicated crown fracture.

  9. 三种基底冠对牙龈缘组织影响的临床比较%Clinical comparoson of three different kinds of ceramic crowns on marginal gingivae

    Institute of Scientific and Technical Information of China (English)

    区韵婵; 温灵; 段昌华

    2012-01-01

    Objective To compare the impact of complete crowns made by three different materials on the gingival health and pigmentation. Methods Forty patients were selected randomly and divided into three gr,oups:metal-ceramic crowns of Ni-Cr alloy;metal -ceramic crowns of Pd-Ag alloy; and zirconia all-ceramic crowns.After1,2 and 3 years follow up, the marginal gingival bleeding index and pigmentation were examined. The data were analyzed by SPSS 13.0 software. Results Givngival inflammation or pigmentation was observed in 15 cases of Ni-Cr group.Two cases of Pd-Ag alloy metal-ceramic crowns with discolored gingivae were observed. No gingival inflammation or pigmentation was observed in zirconia all-ceramic group. Conclusion The metal-ceramic crowns of Pd-Ag alloy and zirconia all -ceramic crowns showed good biocompatibility. There were no adverse effects of all-ceramic crowns on gingival health. The Pd-Ag alloy metal ceramic crowns would not cause obvious harm to the marginal gingival, while the Ni-Cr alloy metal ceramic crowns may increase the risk of gingival bleeding and pigmentation.%目的:观察比较非责金属(镍铬合金)、贵金属(钯银合金)和全瓷(二氧化锆全瓷)内冠三种基底烤瓷冠对牙龈组织的影响.方法:选取3种基底烤瓷冠各40例从牙龈充血和色素沉着等方面进行统计学分析.结果:镍铬合金为基底烤瓷冠修复后出现牙龈异常或龈缘色素沉着15例,钯银合金为基底烤瓷冠修复后出现牙龈异常或龈缘色素沉着2例,全瓷(二氧化锆全瓷)内冠为基底烤瓷冠修复后无1例出现牙龈异常或龈缘色素沉着.结论:贵金属基底烤瓷冠和全瓷烤瓷内冠具有良好的生物相容性,不容易造成牙龈炎及过敏反应,对牙龈无不良影响,减少了龈缘色素沉着的发生,而镍铬合金为基底烤瓷冠可引起龈缘组织异常反应.

  10. 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.

  11. [Artificial crowns influence upon edge parodontium status].

    Science.gov (United States)

    Zhulev, E N; Serov, A B

    2010-01-01

    With the aim of prosthetic treatment efficacy increase study of edge parodontium tissue reaction upon different types of artificial crowns was done and methods of chronic localized parodontitis prevention were developed. Changes of the main gingival fluid characteristics (amount, acidity, interleukine-1beta concentration) and indicators of microcirculation in edge parodontium of the teeth under the artificial crowns influence were disclosed. There were developed methods of chronic localized parodontitis prevention produced by artificial crowns edge.

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

    OpenAIRE

    Kiran Kumar Ganji; Veena Ashok Patil; Jiji John

    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...

  13. 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.

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

    OpenAIRE

    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. ...

  15. 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.

  16. 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

  17. 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

  18. 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

  19. Clinical Effect of Fiber Post Combined With Zirconia Crown in the Treatment of Large Area Defect of Molars%探讨纤维桩联合氧化锆全冠修复磨牙大面积缺损的临床效果

    Institute of Scientific and Technical Information of China (English)

    谭洋

    2016-01-01

    Objective To explore the clinical effect of fiber post combined with zirconia crown in the treatment of large area defect of molars. Methods 30 cases(34 teeth)with large area defect were selected in our hospital from May 2014 to May 2015. All patients were treated with quartz fiber post and zirconia all ceramic crowns. Results After the restoration,the integrity of the restoration,the edge suitability and anatomical shape, color,gingival conditions,there were significant changes. Conclusion Quartz fiber post and zirconia all ceramic crown,used in the repair of large area of molars,clinical effect is better.%目的:探究纤维桩联合氧化锆全冠修复磨牙大面积缺损的临床效果。方法选取我院2014年5月~2015年5月收治的30例(34颗)磨牙牙体组织大面积缺损,所有患者均通过石英纤维桩、氧化锆全瓷冠修复。结果修复后,修复体完整性、边缘适合性和解剖外形、颜色、牙龈情况,均有改变。结论石英纤维桩、氧化锆全瓷冠,应用于磨牙大面积缺损修复中,临床效果较佳。

  20. 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.

  1. Fracture resistance of zirconia-composite veneered crowns in comparison with zirconia-porcelain crowns.

    Science.gov (United States)

    Alsadon, Omar; Patrick, David; Johnson, Anthony; Pollington, Sarah; Wood, Duncan

    2017-02-11

    The objectives were to evaluate the fracture resistance and stress concentration in zirconia/composite veneered crowns in comparison to zirconia/porcelain crowns using occlusal fracture resistance and by stress analysis using finite element analysis method. Zirconia substructures were divided into two groups based on the veneering material. A static load was applied occlusally using a ball indenter and the load to fracture was recorded in Newtons (N). The same crown design was used to create 3D crown models and evaluated using FEA. The zirconia/composite crowns subjected to static occlusal load showed comparable results to the zirconia/porcelain crowns. Zirconia/composite crowns showed higher stress on the zirconia substructure at 63.6 and 50.9 MPa on the zirconia substructure veneered with porcelain. In conclusion, zirconia/composite crowns withstood high occlusal loads similar to zirconia/porcelain crowns with no significant difference. However, the zirconia/composite crowns showed higher stress values than the zirconia/porcelain crowns at the zirconia substructure.

  2. 不同长度的玻璃纤维桩修复对下颌前磨牙抗折强度的影响%Effects of Fracture Resistance on Mandible Premolars Restored with Different Glass Fiber Post Lengths

    Institute of Scientific and Technical Information of China (English)

    李张维; 吴妹娟; 刘雪云; 潘宣; 李梁

    2011-01-01

    Objective To compare the influence of different glass - fiber post lengths on teeth fracture resistance.Metbods Thirty extracted human mandible premolars were endodontically treated after being cut off the crowns from the cemento - enamel junction.The teeth were randomly and equally divided into A, B,C groups which were post lengths of 5mm ( shorter than 1/1 clinical crown length) ,7mm ( 1/1 clinical crown length) , and 9mm ( longer than 1/1 clinical crown length) respectively.And then, all of them were restored with resin cores and metal crowns.All the teeth were fixed in a umversal text machine after embedded in acrylic resin blocks,which were tested for the fracture resistance,and recorded the counts and observed the fracture mode.Results Fracture resistance of group A of restoration was significantly lower than that of B group and C group (P <0.05).Fracture resistances of group B and C,however,were not s]gnificantly different ( P > 0.05 ) .Conclusion Glass fiber post lengths should not be shorter than clinical crowns when we use thcm to restore dcntal defects.%目的 比较玻璃纤维桩长度对牙齿抗折强度的影响.方法 选择30颗近期因正畸完整拔除的下颌前磨牙,自釉牙骨质界处截冠后行完善的根管治疗,随机分为A、B、C 3组,每组10颗.对应每组按5mm(短于修复体牙冠的长度),7mm(等于修复体牙冠的长度),9mm(大于修复体牙冠的长度)长度的纤维桩修复,树脂核加金属冠修复外形.自凝塑料包埋后,固定于万能试验机上测试实验牙的抗折强度,记录读数并观察修复体折裂模式.结果 A组的修复体抗折强度低于B组与C组(P0.05).结论 使用玻璃纤维桩修复缺损牙体时,桩的长度不应短于临床牙冠的长度.

  3. 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.

  4. 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

  5. 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

  6. A preliminary study on the short-term efficacy of chairside computer-aided design/computer-assisted manufacturing- generated posterior lithium disilicate crowns.

    Science.gov (United States)

    Reich, Sven; Fischer, Sören; Sobotta, Bernhard; Klapper, Horst-Uwe; Gozdowski, Stephan

    2010-01-01

    The purpose of this preliminary study was to evaluate the clinical performance of chairside-generated crowns over a preliminary time period of 24 months. Forty-one posterior crowns made of a machinable lithium disilicate ceramic for full-contour crowns were inserted in 34 patients using a chairside computer-aided design/computer-assisted manufacturing technique. The crowns were evaluated at baseline and after 6, 12, and 24 months according to modified United States Public Health Service criteria. After 2 years, all reexamined crowns (n = 39) were in situ; one abutment exhibited secondary caries and two abutments received root canal treatment. Within the limited observation period, the crowns revealed clinically satisfying results.

  7. Dental ceramics and the molar crown testing ground

    Directory of Open Access Journals (Sweden)

    Van P. Thompson

    2004-01-01

    Full Text Available 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, and flexural cracking. Constitutive equations based upon materials properties have been developed that predict the damage modes operational for a given ceramic and thickness. Ceramic thickness or thickness of the stiff supporting core in layer crowns is critical in flexural cracking as well as the flaw state of the inner aspect of the crown. The elastic module of the supporting structure and of the luting cement and its thickness play a role in flexural fracture. Clinical studies of ceramics extending over 16 years are compared to the above relationships and predictions. Recommendations for clinical practice are made based upon the above.

  8. 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.

  9. 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.

  10. Fracture resistance of porcelain veneered zirconia crowns with exposed lingual zirconia for anterior teeth after thermal cycling: An in vitro study

    OpenAIRE

    Amir Rad, Fatemeh A.; Succaria, Faysal G.; Morgano, Steven M.

    2015-01-01

    Statement of problem: In some clinical conditions minimally invasive complete crown tooth preparations are indicated. This is especially true when gross removal of tooth structure would weaken the remaining tooth or violate the vitality of the dental pulp. Objective: The purpose of this study was to investigate the influence of (1) exposed lingual zirconia with veneered zirconia crowns, and (2) reduced lingual thickness of monolithic lithium disilicate crowns on the fracture resistance of ...

  11. A short-term clinical evaluation of effectiveness of the fixed implantation of Ankylos implant system with multiple crowns%Ankylos种植系统多牙固定修复短期临床疗效评价

    Institute of Scientific and Technical Information of China (English)

    郭照中; 张恒; 杨旭; 周婷婷; 刘学

    2012-01-01

    目的 评价Ankylos种植体用于固定修复多牙缺失的临床应用效果.方法 临床选择21例多牙缺失患者完成Ankylos 68枚种植体进行潜入式种植手术,部分骨量不足的患者,同期使用膜引导骨再生术、上颌窦内提升术或上颌窦外提升术.Ⅱ期手术两周后,按照常规方法完成金钯合金烤瓷冠修复.术后随访,检查修复体与基台的稳定性,种植体周围牙龈组织的健康状况;通过X线检查观察骨组织的吸收情况及基台的密合程度;调查患者对种植义齿咀嚼、美观功能的主观满意度.种植后及义齿修复后的临床观察期为1~2.5年.结果 冠桥修复后,1例患者的1枚种植体在种植修复后1个月时,发生种植体周围炎;1例在修复后1年烤瓷冠崩瓷;其余种植体均稳定,无明显骨吸收,种植体基台界面密合,牙龈组织健康.按种植成功标准,修复成功66枚,成功率97.1%;失败2枚,占2.9%.结论 Ankylos种植体用于多牙缺失的固定修复具有良好的临床效果.%Objective To evaluate the clinical effects of Ankylos implant system to restore the loss of more than one teeth. Methods Totally, 21 cases with loss of more than one teeth were investigated, and a total of 68 implants were placed from January, 2008 to May, 2010. All the patients had undergone routinely two-stage surgery. When patients showed deficient alveolar ridge, guided bone regeneration (GBR), osteotome sinus floor elevation, lateral antroslomy surgery with simultaneous placement of implants were applied. They were restored with platinum eeramic crowns. All implants were followed up, and records were kept about stability of the implants and abutments, conditions of the surrounding soft tissues, sealability of implant abutment junction, the marginal bone loss through X-ray checking, satisfaction of the patients to mastication, and other aspects of the restorations. The follow- up time was 1-2.5 years. Results Among all of the

  12. 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.

  13. 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.

  14. Comparison of the clinical value of porcelain veneer and all ceramic crowns in the restoration of anterior teeth%烤瓷贴面和全瓷冠在前牙美容修复中的临床应用价值比较

    Institute of Scientific and Technical Information of China (English)

    刘卫锋; 刘继华; 闫慧鑫; 王生党; 王垚

    2015-01-01

    目的:旨在比较烤瓷贴面和全瓷冠在前牙美容修复中的临床效果。方法选择2012年1月至2013年1月在我院接受烤瓷贴面和全瓷冠前牙美容修复的患者127例(320颗),根据患者的牙齿情况选择修复材料,其中接受烤瓷贴面修复患者70例(144颗),全瓷冠修复患者57例(176颗),320颗前牙均采用耐火代型技术进行修复,对所有患者随访2年。为了评价2种修复方式在前牙美容中的效果,分别在修复后3个月和24月后比较近期的美容效果和远期的完整性效果。结果经烤瓷贴面和全瓷冠修复后,患者均达到较好的近期美容效果,其主观满意度均达到100%,2种修复方式差异无统计学意义(P=0.51);全瓷冠修复的客观满意度为94.7%,高于烤瓷贴面(90.0%),表明全瓷冠的遮色效果优于烤瓷贴面。修复2年后全瓷冠的完好率仍为100%,烤瓷贴面的完好率为96.0%,二者差异有统计学意义(P=0.04),全瓷冠修复的远期完整性效果更佳。结论烤瓷贴面和全瓷冠对于前牙修复均能收到较好的美容效果,全瓷冠修复的远期完整性效果优于烤瓷贴面修复。%Objective To compare the clinical effects of porcelain veneer and all ceramic crowns in the cosmetic restoration of anterior teeth .Methods One hundred and twenty-seven patients ( 320 teeth ) , who received porcelain veneer and all ceramic crowns in the cosmetic restoration of anterior teeth from January , 2012 to January, 2013 in our hospital were chosen for our study .The repair materials for the patients′teeth were selected in accordance with the patient conditions of the teeth .All the 320 anterior teeth were repaired with refractory generation technology , of which 70 cases (144 teeth) were repaired with porcelain veneer and 57 cases (176 teeth) were repaired with all ceramic crowns , and all the patients had medical follow-ups for 2

  15. Clinical Effectiveness of Modified SOFA (MSOFA scoring system for predicting mortality and length of stay in patients hospitalized in intensive care unit

    Directory of Open Access Journals (Sweden)

    Hassan Babamohamadi

    2016-10-01

    Full Text Available Background: The ability to recognize the severity of the disease in those who their survival depend entirely on admission to the intensive care unit, is very valuable clinically. This study aimed to evaluate the clinical effectiveness of MSOFA scale to predict mortality and length of stay in ICU patients respectively. Methods: This was a retrospective cross-sectional study conducted on hospital records of patients admitted to the intensive care unit of Kowsar Hospital of Semnan. The data collection tool was a demographic questionnaire and MSOFA scale. Finally, data were analyzed using SPSS version 16 by logistic regression and ROC curve. Results: The study of 105 patients' records of the intensive care unit in 2015 showed that 45/7% of patients were died, 15/2% and 39% were discharged and moved to other wards respectively. The results of logistic regression analysis and ROC curve showed that this criterion had moderate sensitivity and specificity for prediction of mortality and length of stay in ICU patients (Area=0/635, CI= 0/527-0/743( and each unit increase in MSOFA score is accompanied by increasing 32 percent chance of death (OR=1.325; 95% CI:1.129,1.555; P=0.001(. Also each unit increase in MSOFA score accompanied by increasing 19% length of stay in ICU (OR=1.191; 95% CI: 1.034, 1.371; P=0.015(. Conclusion: The results of this study showed that the MSOFA scale is not useful tool to predict the length of stay and mortality of patients admitted to the intensive care unit.

  16. Clinical evaluation of quartz fiber post and zirconia all-ceramic crowns in restoring extensively damaged molar%纤维桩联合氧化锆全冠修复磨牙大面积缺损的临床评价

    Institute of Scientific and Technical Information of China (English)

    张海燕; 彭利伟; 郭东晓

    2012-01-01

    目的:评价石英纤维桩联合氧化锆全瓷冠在磨牙大面积缺损修复活疗中的短期临床效果.方法:对28例患者32颗已完善的根管治疗的磨牙残根、残冠,采用石英纤维桩联合氧化锆全瓷冠进行修复.修复后1、6、12个月随访检查,包括修复体完整性、边缘适合性、解剖外形、颜色及牙龈.结果:修复体的完整性好(93.75%),有2例因咬过硬食物崩瓷,边缘适合性及解剖外形良好,修复体颜色与邻牙协调一致(84.37%),纤维桩核及冠均无松动、脱落,X线牙片示纤维桩与根管壁密贴,未见折裂等.结论:石英纤维桩联合氧化锆全瓷冠在磨牙大面积缺损修复治疗中可取得良好的近期临床效果.%Objective To evaluate the clinical effect of quartz fiber post and zirconia all-ceramic crowns in restoring extensively damaged molar. Methods A total of 32 molars of 28 patients were included.After complete root canal therapy,the teeth were restored with quartz fiber posts and zirconia all -ceramic crowns. Follow -up survey were conducted 1month,6 months and 12 months later,including the intactness,marginal adaptation,anatomical contour and color of prostheses and gingival health. Results 93.75% of prostheses were found to be intact;little wane was found in two all -ceramic crowns due to hard food biting.Marginal adaptation and anatomical contour was good,color of prostheses in harmony with adjacent teeth (84.37%).No loosening or exfoliation was found among quartz fiber posts and composite resin core.Roentgen diagnosis revealed posts' adaptation to root canal without fracture of posts and cores in any prostheses. Conclusion Quartz fiber posts and zirconia all-ceramic crowns are reliable and ideal materials in the restoration of extensively damaged molar.

  17. 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.

  18. Influence of thermomechanical fatigue loading on the fracture resistance of all-ceramic posterior crowns.

    Science.gov (United States)

    Senyilmaz, Dilek Pinar; Canay, Senay; Heydecke, Guido; Strub, Joerg Rudolf

    2010-06-01

    This study evaluated the fracture resistance and the survival rate of different all-ceramic crowns in-vitro after thermomechanical fatigue loading in comparison to porcelain-fused-to-metal posterior crowns. Sixteen crowns for human mandibular first molars were made of each of the following: Cercon, IPS-Empress 2 In-Ceram Zirconia, Procera AllZircon and porcelain-fused-to-metal. Half of the specimens of each group was thermocycled and dynamically loaded using a chewing simulator All samples were thereafter tested for the maximum fracture resistance. The survival rates after 1-2 million cycles in the artificial mouth were 100% in all the tested crown systems. The chewing simulation and thermocycling did not significantly decrease the fracture strength of the ceramic crowns (P>0.005). The median fracture load of Cercon, Procera AllZircon, In-Ceram Zirconia and PFM was significantly higher than IPS-Empress 2 both for loaded and non loaded groups (PZirconia and PFM was not significant (P>0.005). All-ceramic systems showed fracture load values similar to those of porcelain-fused-to-metal molar crowns and therefore may be considered for use in clinical studies.

  19. 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.

  20. Triple-tray和常规印模技术修复全冠所需的临床与工艺操作时间的对比研究%Comparasion of clinical and technical operating time of full-crown restorations between traditisonal and Triple-tray impression techniques

    Institute of Scientific and Technical Information of China (English)

    邢燕西; 彭东; 王宇光

    2012-01-01

    Objective: To compare the difference of clinical and technical processes of full-crown restorations by using traditional and Triple-tray impression techniques, consumed materials and time estimated in every procedure of these two methods. Methods; Four veteran clinicians were selected to carry out full-crown restorative treatment for 124 patients (130 crowns) . From one impression, dentists could make casts of prepared teeth and the opposing dentition and register the interocclusal relationship. After tooth preparation, Impregum Penta polyether impression was fabricated for 76 cases (80 crowns) by Triple-tray method and 48 cases (50 crowns) by conventional method. During the whole processes, the consumption of impression materials and plaster, the time of fitting on the articulator, manufacturing procedure and try-in in clinical practice were recorded. The differences of material and time consumption in every procedure of these two methods were evaluated by Independent-Samples t test. Results; The consumptionof impression materials and plaster of Triple-tray impression technique was significantly less than that of traditional impression technique ( P < 0.01) , and average time in every procedure of Triple-tray impression technique was remarkablely reduced compared with that of the traditional impression technique (P <0. 01) . Triple-tray impression technique reduces operating costs and the possibility of error. Conclusion: Compared with traditional impression technique, Triple-tray impression technique could reduce the consumption of time and materials in clinical and technical processes.%目的:通过记录全冠修复体临床操作及工艺制作步骤所需的时间,比较常规印模与Triple-tray印模技术的差异.方法:由4名具有3年以上临床经验的医师,对124名患者(130颗患牙)进行全冠修复治疗.口腔医师可以利用一副印模同时制取预备后牙齿及对颌牙列的石膏模型,并记录牙列间的牙尖交错关

  1. 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...

  2. 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...

  3. 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.

  4. 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.

  5. Clinical retrospective analysis of all-ceramic single crown in terms of fracture resistance with CAD/CAM zirconia-base:a four-year follow-up%CAD/CAM氧化锆全瓷单冠抗折裂随访4年临床分析

    Institute of Scientific and Technical Information of China (English)

    郑茜聪; 蔡志斌

    2015-01-01

    Objective To evaluate the fracture resistance of CAD / CAM zirconia all-ceramic crowns. Methods 284 all-ceramic crowns were fabricated for 189 patients. 226 restorations of 156 patients were clinically followed up for 2. 5-5. 5 years. The site of crown, fracture or breakage,loose or dislodgement were observed. Results The fracture rate was 0. 9% at 1 year after the insertion date, 2. 1% after two years,3. 3% after three years,7. 1% after four years. Overall the fracture rate was 9. 7% with 226 restorations. Base crown fracture took place in two cases. A statistically significant difference was found for fractures when the opposing dentition of natural teeth and fixed restorations were compared (P = 0. 034). The fractures were most commonly noted when the opposing dentition was a fixed metal ceramic or other ceramic restorations. Conclusions The fracture resistance of CAD / CAM zirconia all-ceramic crowns was acceptable clinically and it can be a preferred esthetic restoration.%目的:回顾分析评价CAD / CAM 氧化锆全瓷单冠抗折裂性能。方法为189例患者制作CAD / CAM 氧化锆全瓷冠284颗,随访到156例患者的226颗全瓷冠,随访2.5~5.5年,对修复体的位置、崩瓷、基底冠折断、修复体松动脱落等情况进行观察。结果 CAD / CAM 全瓷冠1年的折裂率0.9%,2年的折裂率为2.1%,3年的折裂率为3.3%,4年的折裂率为7.1%,观察期间全瓷冠的总折裂率为9.7%。其中2例患者发生基底冠折裂。当对颌分别为天然牙或瓷修复体时,全瓷冠的折裂率有显著性差异( P =0.034)。全瓷冠的折裂后牙明显高于前牙区(P <0.01)。结论 CAD / CAM 氧化锆全瓷冠整体抗折裂性能临床可接受,可作为临床首选的美学修复体。

  6. Clinical Research of Strip Crowns in Restoration of Multi-Surface Caries Decay in Primary Anterior Teeth%透明成形冠在大面积龋损乳前牙修复中的应用

    Institute of Scientific and Technical Information of China (English)

    李永吉; 滕立群; 张英华; 于惠娟

    2011-01-01

    Objective To study the application of the strip crowns in restoration of multi-surface caries decay in primary anterior teeth. Methods Seventy-two patients with 174 multi-surface caries of primary anterior teeth were divided into group A ( control group, 86 cases), group B ( experimental group, 88 cases). Teeth were restored with composite resin in group A and strip crowns in group B, respectively. 6 months after therapy, restorations were re-examined at 6month and 18-month follow-up. Results 6-month retention rate was 96.51% for group A and 100% for group B, with no significant difference between two groups. 18-month retention rate was 67.44% for group A and 100% for group B,with significant difference (P u 0. 01 ) between two groups. Conclusion Strip crowns is a convenient and effective method to restore the multi-surface caries of primary anterior teeth.%目的 探讨应用Strip crowns透明成形冠对大面积龋损的乳前牙进行复合树脂全冠修复的效果.方法 72例174颗大面积龋损的乳前牙分为试验组和对照组.试验组88颗,应用Strip crowns透明成形冠进行复合树脂全冠修复;对照组86颗,用光固化复合树脂直接充填修复.经6个月、18个月随访观察修复体状态.结果 经6个月观察,修复体保存率试验组和对照组分别为100%、96.51%,两组间差异无统计学意义(P>0.05).经18个月观察,修复体保存率试验组和对照组分别为100%、67.44%,两组间差异有统计学意义(P<0.01).结论 应用Strip crowns透明成形冠对大面积龋损的乳前牙进行复合树脂全冠修复,其疗效可靠,明显优于复合树脂直接充填修复,具有良好的应用前景.

  7. The Crown Bite Jumping Herbst.

    Science.gov (United States)

    Owen, Reuel

    2003-01-01

    The Crown Bite Jumping Herbst Appliance is evaluated and combined with Straight Wire Arch Fixed Orthodontics in treatment of Class II, Division I malocclusions. This article will evaluate a combined orthodontic approach of "straightening teeth" and an orthognathic approach of "moving jaws or making skeletal changes." Orthodontic treatment cannot be accomplished well without establishing a healthy temporomandibular joint. This is defined by Keller as a joint that is "noiseless, painless and has a normal range of motion without deviation and deflection." It is not prudent to separate orthodontic treatment as its own entity without being aware of the changes in the temporomandibular joint before, during and after treatment. In other words, "If you're doing orthodontics you're doing TMJ treatment." One should treat toward a healthy, beautiful face asking, "Will proposed treatment achieve this goal?" Treatment should be able to be carried out in an efficient manner, minimizing treatment time, be comfortable and affordable for the patient, and profitable for the dentist. The finished treatment should meet Andrews' Six Keys of Occlusion, or Loudon's Twelve Commandments. Above all, do no harm to the patient. We think that a specific treatment plan can embrace these tenets. The focus will be to show Class II treatment using a modified Herbst Appliance and fixed straight wire orthodontics.

  8. 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.

  9. Clinical observation on the application of MTA in vital pulpotomy for crown fracture with pulp exposure%矿物三氧化物凝聚体用于冠折露髓活髓切断术临床观察

    Institute of Scientific and Technical Information of China (English)

    韩爱军; 刘盘龙

    2013-01-01

    目的 比较矿物三氧化物凝聚体(MTA)和氢氧化钙用于冠折露髓活髓切断术的临床疗效.方法 选择冠折年轻恒前牙76颗,随机分成2组,每组38颗.实验组MTA用于活髓切断术盖髓,对照组以氢氧化钙盖髓.术后对患者进行2年的临床疗效随访,观察根尖继续发育情况.结果 实验组成功率为94.6%,对照组成功率为71.4%,2组差异有统计学意义(P<0.01).结论 MTA用于冠折露髓活髓切断术的临床疗效优于氢氧化钙.%Objective To compare the clinical effects of vital pulpotomy with mineral trioxide aggregate (MTA) and calcium hydroxide during the treatment of crown fracture with pulp exposure.Methods 76 young permanent teeth with crown fracture and pulp exposure were selected in the study.All selected teeth were randomly divided into control group (treated with calcium hydroxide) and experimental group (treated with MTA),38 cases in each group.All the children were followed up for 2 years to observe the development of apex of root of teeth.Results The rate of successful apex closure on apexification in experimental group was 94.6%,compared to 71.4% in control group.There was statistically significant difference on the success rate of vital pulpotomy with MTA and calcium hydroxide (P < 0.01).Conclusions The clinical effects of vital pulpotomy in crown fracture with pulp exposure with MTA is better than that with calcium hydroxide.

  10. 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.

  11. 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.

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

    OpenAIRE

    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...

  13. Clinical retrospective analysis of All-ceramic crowns and bridges with CAD/CAM Zirconia-base: A Four-year Follow up%CAD/CAM氧化锆全瓷冠桥随访4年的临床分析

    Institute of Scientific and Technical Information of China (English)

    孙凤; 张相皡; 晁春良; 杜阳; 李祎

    2011-01-01

    Objective: To evaluate the clinical performance of CAD/CAM zirconia all-ceramic crowns and fixed partial dentures (FPDs). Methods: 681 all-ceramic crowns or FPDs were fabricated for 267 patients. 562 restorations of 205 patients were clinically followed for 2-6 years. Recalls were made 3 months after cementation. Porcelain fracture performance was compared between restorations in anterior and premolar and molar. Using modified US Public Health Service criteria, judgments were made on marginal integrity and shade and color. Loose or dislodgement, fracture and breakage were reviewed in the annually follow up. Results: Chipping rate is 3.3 l%,Chipping of restorations in molars were higher than the restorations in premolars and in anterior teeth (x2 test, P< 0.01). Different technicians had significant influence (x2 test, P< 0.001) on color match of crowns, while different color of abutments did not (x2 test, P> 0.05). The authors rated 90.8% as good or better in regard to color match, 99.2% of the restorations were ranked as good or better on marginal integrity, Loose or dislodgement0.35%, 0% for fracture of Zirconia-based. Conclusion: Zirconia-based all-ceramic crowns with CAD/CAM show good marginal integrity and shade compatibility with nature teeth, with a clinically acceptable chipping rate, This material can be used in conventional and esthetic prosthetic dentistry and especially is the preferred esthetic restorations in case of abutment teeth discoloration. Further studies are needed to reduce the chipping in molars and to improve the marginal integrity of long bridges.%目的:回顾分析评价CAD/CAM氧化锆全瓷冠桥的修复效果.方法:为267位患者制做CAD/CAM氧化锆全瓷冠或桥681件,随访了205例患者的562件全瓷冠桥,随访时间2-6年.对修复体的崩瓷、全瓷冠的颜色与修复体的边缘密合度进行评价.结果:CAD/CAM氧化锆全瓷冠的崩瓷率3.31%,与修复体部位有明显相关性(P<0.01),不

  14. Mapping the carriage of flaA-restriction fragment length polymorphism Campylobacter genotypes on poultry carcasses through the processing chain and comparison to clinical isolates.

    Science.gov (United States)

    Duffy, Lesley L; Blackall, Patrick J; Cobbold, Rowland N; Fegan, Narelle

    2015-06-01

    Poultry are considered a major source for campylobacteriosis in humans. A total of 1866 Campylobacter spp. isolates collected through the poultry processing chain were typed using flaA-restriction fragment length polymorphism to measure the impact of processing on the genotypes present. Temporally related human clinical isolates (n = 497) were also typed. Isolates were obtained from whole chicken carcass rinses of chickens collected before scalding, after scalding, before immersion chilling, after immersion chilling and after packaging as well as from individual caecal samples. A total of 32 genotypes comprising at least four isolates each were recognised. Simpson's Index of Diversity (D) was calculated for each sampling site within each flock, for each flock as a whole and for the clinical isolates. From caecal collection to after packaging samples the D value did not change in two flocks, decreased in one flock and increased in the fourth flock. Dominant genotypes occurred in each flock but their constitutive percentages changed through processing. There were 23 overlapping genotypes between clinical and chicken isolates. The diversity of Campylobacter is flock dependant and may alter through processing. This study confirms that poultry are a source of campylobacteriosis in the Australian population although other sources may contribute.

  15. 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.

  16. 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.

  17. The 3D Measurement of Chinese Tibia Length and the Clinical Significance%国人胫骨长度的三维测量方法及意义

    Institute of Scientific and Technical Information of China (English)

    李建涛; 周坚锋; 张浩; 李辰; 张立海; 唐佩福

    2016-01-01

    Objective: To accumulate tibia anthropological data of Chinese and explore its clinical significance through Mimics and 3-matic. Methods: Collected the DICOM format data of CT imagine of 199 patients in our hospital. The 3-D model of tibia was reconstructed in Mimics. Then we rotated the tibia model to the standard position in 3-matic software. Statistical analysis was performed by SPSS V.17.0. Results: The mean length of tibia in right sides and left was(358±22)mm samely. The correlation coefficient between tibia length and height was calculated(r=0.84, P=0.000). Simple regression equation for tibia length and height was also obtained. Excluding the height factor to compare the effects of gender factor on tibia length, Covariance analysis showed two groups of men and women tibia length was statistically significant difference(P=0.006). Conclusion: Using Mimics and 3-matic to measure the tibia length is more of precision, easy to operate, and has significant effect to clinical guidance.%目的:通过医学工程学软件对国人胫骨进行三维重建,并进行解剖参数测量,积累国人胫骨人类学资料并探讨其临床意义。方法:收集2013年3月到2014年5月期间在解放军总医院进行下肢动脉造影CT扫描的199例患者数据。通过Mimics软件的阈值分割、区域增长、蒙版编辑等功能重建胫骨三维模型,通过3-matic对重建模型进行标准位置纠正后标记胫骨最近端和最远端端点,并记录其Z轴坐标值,通过SPSS软件对相关参数进行统计学分析。结果:胫骨平均长度为(358±22)mm(295-431mm),左侧胫骨长度为(358±22)mm(296-424mm),右侧胫骨长度为(358±22)mm(295-431mm);男性胫骨长度为(365±19)mm(323-431mm),女性胫骨长度为(342±18)mm(295-397mm)(P=0.000)。胫骨长度与身高成显著的正相关(r=0.84,P=0.000),胫骨长度(mm)为因变量,身高(m)为自变

  18. Working Length Determination Using Cone-Beam Computed Tomography, Periapical Radiography and Electronic Apex Locator in Teeth with Apical Periodontitis: A Clinical Study

    Science.gov (United States)

    de Morais, André Luiz Gomide; de Alencar, Ana Helena Gonçalves; Estrela, Cyntia Rodrigues de Araújo; Decurcio, Daniel Almeida; Estrela, Carlos

    2016-01-01

    Introduction: The purpose of this clinical study was to compare the accuracy of working length (WL) determination using cone-beam computed tomography (CBCT), conventional periapical radiographies and electronic apex locator. Methods and Materials: This study was conducted during root canal treatment of 19 patients with a total of 30 single-rooted teeth diagnosed with apical periodontitis. After taking the initial parallel periapical radiographies, the initial file was advanced into the canal until the WL was detected by the apex locator. Subsequently, the WL was measured and WL radiographies were taken with the file set in the canal. Afterwards, CBCT images were acquired. These three measurements were tabulated and compared and the data were analyzed using the Friedman test. The level of significance was set at 0.05. Results: The mean values for WL determination by electronic apex locator, periapical radiograph and CBCT images were 22.25, 22.43 and 22.65, respectively which was not statistically significant (P>0.05). Conclusion: Working length determination using CBCT images was precise when compared to radiographic method and electronic apex locator. PMID:27471524

  19. 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.

  20. 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.

  1. 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.

  2. 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

  3. 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

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

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    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

  5. 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.

  6. Treatment of crown dilaceration: An interdisciplinary approach

    Directory of Open Access Journals (Sweden)

    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.

  7. 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

  8. 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.

  9. New atraumatic easy removal technique for permanently cemented crown

    Directory of Open Access Journals (Sweden)

    Pravinkumar G Patil

    2012-01-01

    Full Text Available Removal of a permanently cemented crown or fixed partial denture is a cumbersome procedure for a prosthodontist, especially when there is no purchase point available to remove it. The technique described in this article consists of sectioning of a crown on facial surface followed by removal of the crown with orthodontic plier. This technique does not damage the gingival/periodontal tissues or underlying tooth structure as the crown need not to be removed with jerky back-action force.

  10. 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.

  11. A 3-year follow-up study of all-ceramic single and multiple crowns performed in a private practice: a prospective case series

    Directory of Open Access Journals (Sweden)

    Gianluca M. Tartaglia

    2011-01-01

    Full Text Available OBJECTIVES: Zirconia-based prostheses are commonly used for aesthetic crown and fixed restorations, although follow-up data are limited, especially for implant-supported crowns. The aim of this study was to evaluate the threeyear clinical results of the installation of 463 zirconia core crowns by a general dental private practice. METHODS: This study followed 142 patients (69 men and 73 women; aged 28-82 years who had received 248 single crowns (202 tooth-supported, 36 implant-supported and 225 multiple units of up to six elements (81 toothsupported, 144 implant-supported. Clinical events, including fracture and loss of retention, secondary caries, and marginal integrity, were recorded. The overall failure rate was computed for the fractured and lost prostheses. Aesthetic, functional, and biological properties were rated, and patient satisfaction was investigated. RESULTS: During the three-year follow-up period, four patients were lost from the study (18 crowns, 4% of the total crowns. Three of the zirconia prostheses suffered fractures in more than three units (11 crowns; one- vs. three-year follow-up, p,0.05, Wilcoxon signed-rank test, and the cumulative prosthesis survival rate was 98.2%. Twelve units lost retention and were re-cemented, and no secondary caries of the abutment teeth were reported. The aesthetic, functional, and biological properties were generally well-rated, and there were no differences between tooth- and implant-supported crowns. The lowest scores were given regarding the anatomical form of the crowns, as some minor chipping was reported. Relatively low scores were also given for the periodontal response and the adjacent mucosa. Overall, patient satisfaction was high. CONCLUSIONS: At the three-year follow-up, the zirconia-core crowns appeared to be an effective clinical solution as they had favorable aesthetic and functional properties. Only the marginal fit of the prostheses should be improved upon.

  12. 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...

  13. 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.

  14. 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...

  15. 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.

  16. 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.

  17. 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.

  18. Fragment Reattachment after Atypical Crown Fracture in Maxillary Central Incisor

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    Vanessa Torraca Peraro Vaz

    2014-01-01

    Full Text Available Background. Fracture by trauma is one of the most common types of dental injury in the permanent dentition among children and teenagers. Aim. The aim of this study was to report the treatment performed to an atypical dental trauma case in a maxillary central incisor of a young patient by means of reattachment of the tooth fragment. Case Description. A 12-year-old male patient suffered a vertical crown fracture to the maxillary right central incisor. After clinical and radiographic examinations, a conservative restorative treatment which consisted in the reattachment of the tooth fragment with flow resin was performed in order to preserve the dental element and to obtain maximum aesthetics. Conclusion. The reattachment of fractured fragment is a fast and easy technique that can be used successfully as an option to restore dental element which suffered trauma. Clinical Significance. This technique restores the aesthetics and function of the dental element with minimal discomfort to the patient.

  19. Clinical evaluation of restoration of posterior residual crown in low occlusogingival distance with fiber fission post onlay%纤维分体桩高嵌体修复低(牙合)龈距后牙残冠的临床评价

    Institute of Scientific and Technical Information of China (English)

    刘湘宁; 周磊; 赖仁发; 谢黎; 李少冰; 张晔; 熊坤

    2012-01-01

    AIM: To evaluate the clinical effects of restoration of posterior residual crown in low occlusogin- gival distance with porcelain-fused-cobalt-ehromium alloy onlay and zirconium oxide onlay including fiber fission post. METHODS: Fiber fission post porcelain-fused-cobalt-chromium alloy onlay, fiber fission post zirconium oxide onlay and gold alloy fission post onlay were used to restore 90 posterior residual crowns with low occlusogingival distance. Two weeks, 6 months and 24 months after restoration, clinical effects were evaluated based on the Modified United States Public Health Service (USPHS) Criteria. RESULTS; There were no significant differences among three kinds of fission post onlays on each evaluation item and there were no significant differences among 2 weeks, 6 months and 24 months on each evaluation item after each kind of fission post onlay restoration (P≥0.05). CONCLUSION: Fiber fission post porcekin-fused-cobalt-chromium alloy onlay and fiber fission post zirconium oxide onlay showed as good clinical effect as gold alloy fission post onlay when applied for restoration of posterior residual crown with low occlusog-ingival distance. Furthermore, compared with gold alloy onlay, porcelain-fused-metal onlay and full ceramic onlay showed better esthetic effects and could meet various restoration needs.%目的:评价含有纤维分体桩的钴铬合金烤瓷高嵌体以及二氧化锆全瓷高嵌体修复低(牙合)龈距后牙残冠的临床效果.方法:用含纤维分体桩的钴铬合金烤瓷高嵌体、二氧化锆全瓷高嵌体以及金合金分体桩高嵌体修复低(牙合)龈距后牙残冠90个,修复后2周、6个月、24个月随访,对解剖形态、边缘适合性、边缘着色、表面质地、继发龋等临床修复效果进行评价.结果:3种分体桩高嵌体之间以及每种分体桩高嵌体于修复后2周、6个月、24个月之间在各评价项目上均无明显统计学差异(P≥0.05).结论:应用含纤维分体桩的

  20. Effectiveness of the crown polishment as a coadjuvant in periodontal support therapy

    OpenAIRE

    Alvarado Cordero, Jacinto José; Pontificia Universidad Javeriana; Vélez Restrepo, Juan Camilo; Pontificia Universidad Javeriana; Gómez Guzmán, Mauricio; Pontificia Universidad Javeriana; Vieira Ramírez, Andrés Felipe; Pontificia Universidad Javeriana

    2009-01-01

    OBJECTIVE: Determine the effectiveness of crown polishing in the maintenance periodontal support therapy for the control and reduction of the clinical sings of periodontal disease. METHODS: A randomized controlled clinical trial was carried out with 31 patients with diagnosed chronic periodontitis who were under periodontal maintenance phase, with a minimum of 20 teeth in mouth, non smokers and smoking less than 5 cigarrettes/day, without systemic compromise, orthodontic devices or previous a...

  1. 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.

  2. 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

  3. 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.

  4. 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

  5. Genotyping of Candida orthopsilosis clinical isolates by amplification fragment length polymorphism reveals genetic diversity among independent isolates and strain maintenance within patients.

    Science.gov (United States)

    Tavanti, Arianna; Hensgens, Lambert A M; Ghelardi, Emilia; Campa, Mario; Senesi, Sonia

    2007-05-01

    Candida parapsilosis former groups II and III have recently been established as independent species named C. orthopsilosis and C. metapsilosis, respectively. In this report, 400 isolates (290 patients) previously classified as C. parapsilosis by conventional laboratory tests were screened by BanI digestion profile analysis of the secondary alcohol dehydrogenase gene fragment and by amplification fragment length polymorphism (AFLP). Thirty-three strains collected from 13 patients were identified as C. orthopsilosis, thus giving the first retrospective evidence that C. orthopsilosis was responsible for 4.5% of the infections/colonization attributed to C. parapsilosis. AFLP was proven to unambiguously identify C. orthopsilosis at the species level and efficiently delineate intraspecific genetic relatedness. A high percentage of polymorphic AFLP bands was observed for independent isolates collected from each patient. Statistical analysis of the pairwise genetic distances and bootstrapping revealed that clonal reproduction and recombination both contribute to C. orthopsilosis genetic population structure. AFLP patterns of sequential isolates obtained from two patients demonstrated that a successful strain colonization within the same patient occurred, as revealed by strain maintenance in various body sites. No association between AFLP markers and drug resistance was observed, and none of the clinical C. orthopsilosis isolates were found to produce biofilm in vitro.

  6. 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

  7. 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.

  8. 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 .

  9. Comparison of fracture toughness of all-ceramic and metal-ceramic cement retained implant crowns: an in vitro study.

    Science.gov (United States)

    Rao, S; Chowdhary, R

    2014-12-01

    To evaluate the fracture toughness of cement-retained implant-supported metal-ceramic molar crown with that of all-ceramic crowns, fabricated using IPS Empress 2 and yttria-stabilized zirconia copings. An dental implant and abutment was embedded in a clear polymethyl methacrylate model. A wax pattern reproducing the anatomy and dimension of a mandibular molar was made using inlay wax. Copings were made from the manufacturers guidelines for zirconia, metal ceramic and empress crown, in total of 21 copings, which were built for the crowns with metal layering ceramics specified by the manufacturers. The polymethylmethacrylate block-implant abutment complex was mounted on universal testing machine, and a static continuos vertical compressive load with a crosshead speed of 0.5 mm/min was applied. The breaking load and the peak load (in kilo Newtons) were recorded. The fractures for group I (zirconia-ceramic) and group II (metal-ceramic) occurred on the mesio-buccal aspect of the crowns involving the veneered ceramic layer while the catastrophic/bulk fracture was not observed. The mean value of breaking load for zirconia-ceramic, metal-ceramic and IPS-empress 2 was 3.4335, 3.071 and 1.0673 kN respectively. The mean value of peak load for zirconia-ceramic, metal-ceramic and IPS-empress 2 was 4.7365, 3.2757 and 1.566 kN respectively. It can be concluded that the zirconia-ceramic crown with the fracture toughness of 4.7365 ± 2.2676 kN has sufficient strength to allow clinical testing of these crowns as an alternative for metal-ceramic crowns (3.2757 ± 0.4681 kN).

  10. 4′-Formylbenzo-15-crown-5

    Directory of Open Access Journals (Sweden)

    Conrad Fischer

    2008-08-01

    Full Text Available In the title compound (systematic name: 17-formyl-2,5,8,11,14-pentaoxabicyclo[13.4.0]nonadeca-15,17,19-triene, C15H20O6, the 15-crown-5 ring adopts a twisted conformation. The formyl group is coplanar with the benzene ring. The crystal packing is stabilized by C—H...O interactions involving the C=O group and ether O atoms as acceptors and methylene CH groups as donors.

  11. The use of stainless steel crowns.

    Science.gov (United States)

    Seale, N Sue

    2002-01-01

    The stainless steel crown (SSC) is an extremely durable restoration with several clear-cut indications for use in primary teeth including: following a pulpotomy/pulpectomy; for teeth with developmental defects or large carious lesions involving multiple surfaces where an amalgam is likely to fail; and for fractured teeth. In other situations, its use is less clear cut, and caries risk factors, restoration longevity and cost effectiveness are considerations in decisions to use the SSC. The literature on caries risk factors in young children indicates that children at high risk exhibiting anterior tooth decay and/or molar caries may benefit by treatment with stainless steel crowns to protect the remaining at-risk tooth surfaces. Studies evaluating restoration longevity, including the durability and lifespan of SSCs and Class II amalgams demonstrate the superiority of SSCs for both parameters. Children with extensive decay, large lesions or multiple surface lesions in primary molars should be treated with stainless steel crowns. Because of the protection from future decay provided by their feature of full coverage and their increased durability and longevity, strong consideration should be given to the use of SSCs in children who require general anesthesia. Finally, a strong argument for the use of the SSC restoration is its cost effectiveness based on its durability and longevity.

  12. 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.

  13. Spiral implants bearing full-arch rehabilitation: analysis of clinical outcome.

    Science.gov (United States)

    Danza, Matteo; Grecchi, Francesco; Zollino, Ilaria; Casadio, Claudia; Carinci, Francesco

    2011-08-01

    A spiral implant (SPI) is a conical internal helix implant with a variable thread design which confers the characteristic of self drilling, self tapping, and self bone condensing. The effectiveness of this type of implant has been reported in several clinical situations. However, because there are no reports that specifically focus on one of the biggest challenges in oral rehabilitation, that is, full arch rehabilitation, it was decided to perform a retrospective study. The study population was composed of 23 patients (12 women and 11 men, median age 57 years) for evaluation and implant treatment between January 2005 and June 2009. Two-hundred six spiral family implants (SFIs) were inserted with a mean postloading follow-up of 23 months. Several variables were investigated: demographic (age and gender), anatomic (maxilla and mandible, tooth site), implant (type, length, and diameter), surgical (surgeon, postextractive, flapless technique, grafts), and prosthetic (implant/crown ratio, dentition in the antagonist arch, type of loading, and computerized tomography [CT] planning) variables. Implant loss and peri-implant bone resorption were evaluated. Univariate and multivariate tests were performed. Survival and success rates were 97.1% and 82.5%, respectively. Only implant length and implant/crown ratio showed statistical significance in determining a better clinical outcome. In conclusion, SFIs are a reliable tool for the most difficult cases of oral rehabilitation. No differences were detected among implant type. Length and implant/crown ratio can influence the crestal bone resorption with better result for longer fixtures and a higher implant/crown ratio. In addition, banked bone derived from living donors can be used to restore alveolar ridge augmentation without adverse effects. Finally, flapless and CT-planned surgery did not significantly increase the clinical outcome in most complex rehabilitation.

  14. Rehabilitation of complicated crown-root fracture by invisible approach

    Science.gov (United States)

    Rani, V. Leela; Rajalingam, S.; Hemalatha, R.; Jananee, J.

    2016-01-01

    Dental trauma is one of the most common and significant problems met in all dental offices almost every day. In particular, injury to the anterior teeth is more vulnerable as it may affect the psychosocial behavior, severe emotional complications can occur leading to disturbances in their mental attitude. Cosmetic (lingual) orthodontics is the recent development in the field of dentistry in the last few decades. Patients are more concerned about their appearance during the treatment and are affected by psychosocial issues because of labially placed brackets, thus leading to the evolution of lingual orthodontic appliances. In this article, we are sharing our clinical experience treating a complicated crown-root fracture using the lingual orthodontic technique. PMID:27829773

  15. 单个上前牙即刻种植即刻非功能修复的临床疗效观察%The clinic effect of immediate single-tooth implants and non-functional provisional crowns in the anterior maxilla

    Institute of Scientific and Technical Information of China (English)

    罗智斌; 曾融生; 罗志宾; 林丽婷; 徐佳丽

    2009-01-01

    Objective To observe the clinical effect of the restoration of a single upper missing tooth with immediate implant placement and non-functional prosthesis in the aesthetic area. Methods Seven consecutive patients with un-savable single teeth in the aesthetic zone were included. Teeth were extracted and replaced with immediate implant and non-functional provisional crowns. Suitable permanent abutments were chosen and porcelain-fused-metal or all-ceramic restorations were made on the abutments after 6 months. Patients were followed up 1 year after crown insertion. The marginal bone level around the implant and Pink Esthetic Score (PES) value immediately after crown insertion and 1 year later were measured for comparison. Results The success rate of implant was 100%, mesial and distal peri-implant bone changes were (0.79 ± 0.48)mm and (0.71 ± 0.46)mm respectively. The average PES value was (8.6 ± 1.3) and (11.1 ± 1.8), respectively. Significant difference was found by Walcoxon analysis (P=0.027). Conclusions For strictly selected cases, single-tooth immediate implant and immediate non-functional prosthetsis is an effective method. Good appearance can be achieved and the esthetics of peri-implant soft tissue can be improved over time.%目的 探讨美学区单个上前牙即刻种植即刻非功能修复临床疗效.方法 7例上颌单个无法保留患牙,拔除后即刻植入种植体,当日制作并戴入临时树脂冠,6个月后复诊取模,选择合适基台制作永久金属烤瓷或全瓷修复体,最终修复体戴入后1年复诊,比较刚戴入修复体与1年后随诊时种植体周骨组织水平以及红色美学指数(PES)的变化情况.结果 种植体成功率为100%,种植体近、远中周牙槽骨变化分别为(0.79 ± 0.48)mm、(0.71 ± 0.46)mm;刚戴入修复体与1年后随诊时PES值分别为(8.6 ± 1.3)和(11.1 ± 1.8),Walcoxon统计学分析,两者差异有统计学意义(P=0.027).结论 在严格选择病例的情况下,单牙即

  16. Predictable aesthetic replacement of a metal-ceramic crown using CAD/CAM technology: a case report.

    Science.gov (United States)

    Poticny, Daniel; Conrad, Robert

    2005-08-01

    The currently available CAD/CAM technologies present clinicians with various clinical benefits that include durability, marginal adaptation, and precision aesthetics. The clinical and laboratory procedures associated with these CAD/CAM systems differ from one another, and practitioners must understand the indications for each. Office-based systems, as demonstrated in the following case presentation, allow excellent results to be achieved in a single patient visit and provide a viable alternative for today's practice. This case report describes the associated sequences for a posterior CAD/CAM restoration. Learning Objectives This article discusses a protocol for the use of CAD/CAM restorations in the aesthetic replacement of defective posterior crowns. Upon reading this article, the reader should have: * Greater understanding of the in-office CAD/CAM procedures used to fabricate single-visit crowns. * Improved awareness of the bonding protocol used for these all-ceramic crowns.

  17. Reliability of reduced-thickness and thinly veneered lithium disilicate crowns.

    Science.gov (United States)

    Silva, N R F A; Bonfante, E A; Martins, L M; Valverde, G B; Thompson, V P; Ferencz, J L; Coelho, P G

    2012-03-01

    The present investigation hypothesized that the reliability of reduced-thickness monolithic lithium disilicate crowns is high relative to that of veneered zirconia (Y-TZP) and comparable with that of metal ceramic (MCR) systems. CAD/CAM first mandibular molar full-crown preparations were produced with uniform thicknesses of either 1.0-mm or 2.0-mm occlusal and axial reduction, then replicated in composite for standard crown dies. Monolithic 1.0-mm (MON) and 2.0-mm CAD/CAM lithium disilicate crowns, the latter with a buccal thin veneer (BTV) of 0.5 mm, were fabricated and then sliding-contact-fatigued (step-stress method) until failure or suspension (n = 18/group). Crack evolution was followed, and fractography of post mortem specimens was performed and compared with that of clinical specimens. Use level probability Weibull calculation (use load = 1,200 N) showed interval overlaps between MON and BTV. There was no significant difference between the Weibull characteristic failure loads of MON and BTV (1,535 N [90% CI 1,354-1,740] and 1,609 N [90% CI 1,512-1,712], respectively), which were significantly higher than that of Y-TZP (370 N [90% CI 322-427]) and comparable with that of MCR (1,304 N [90% CI 1,203-1,414]), validating the study hypothesis.

  18. Restoring the gingival contour by means of provisional resin crowns after single-implant treatment.

    Science.gov (United States)

    Jemt, T

    1999-02-01

    A consecutive group of 55 patients was treated with 63 single-implant restorations. The soft tissue was allowed to heal to either provisional resin crowns (n = 25) that were placed at the time of second-stage surgery, or to healing abutments (n = 38) before final crown insertion. An index that assessed the size of the interproximal mucosa adjacent to the single-implant restorations was used to evaluate the volume of the papillae 2 years after crown insertion. The results indicated that the use of provisional crowns may restore soft tissue contour faster than healing abutments alone, but the papillae adjacent to single-implant restorations presented similar volume in both groups after 2 years in function. Furthermore, the mean marginal bone loss at the implants was 0.9 mm after 1 year, and no differences were observed between the 2 groups. The present data focus on the need for more scientific data to evaluate different clinical procedures for optimizing esthetic results in implant dentistry.

  19. [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.

  20. 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.

  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

    This is the accepted manuscript version. Published version is available at Acta Odontologica Scandinavica 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 zi...

  2. 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.

  3. Marginal Fit of CEREC Crowns at Different Finish Line Curvatures

    Science.gov (United States)

    2015-06-01

    Mikroleakage - ful crowns and the dental pulp. Journal of Endodontics , 18, 473. Grey, N., Piddock, V., & Wilson, M. {1993). In vitro comparison of...Fox, W. (1989). Compaison of the marginal fit of various ceramic crown systems. Journal of Prosthetic Dentistry, 61 (5), 527-531. Beschnidt, S. M...Strub, J. (1999). Evaluation of the marginal accuracy of different all-ceramic crown systems after simulation in the artificial mouth. Journal of

  4. Characterization of Microsolvated Crown Ethers from Broadband Rotational Spectroscopy

    Science.gov (United States)

    Perez, Cristobal; Schnell, Melanie; Blanco, Susana; Lopez, Juan Carlos

    2016-06-01

    Since they were first synthetized, crown ethers have been extensively used in organometallic chemistry due to their unparalleled binding selectivity with alkali metal cations. From a structural point of view, crown ethers are heterocycles containing oxygen and/or other heteroatoms, although the most common ones are formed from ethylene oxide unit. Crown ethers are conventionally seen as being hydrophilic inside and hydrophobic outside when the structures found for the metal cation complexes are considered. However, crown ethers are extremely flexible and in isolation may present a variety of stable conformations so that their structure may be easily adapted in presence of a strong ligand as an alkali metal cation minimize the energy of the resulting complex. Water can be considered a soft ligand which interacts with crown ethers through moderate hydrogen bonds. It is thus interesting to investigate which conformers are selected by water to form complexes, the preferred interaction sites and the possible conformational changes due to the presence of one or more water molecules. Previous studies identified microsolvated crown ethers but in all cases with a chromophore group attached to the structure. Here we present a broadband rotational spectroscopy study of microsolvated crown ethers produced in a pulsed molecular jet expansion. Several 1:1 and 1:2 crown ether:water aggregates are presented for 12-crown-4, 15-crown-5 and 18-crown-6. Unambiguous identification of the structures has been achieved using isotopic substitution within the water unit. The subtle changes induced in the structures of the crown ether monomer upon complexation and the hydrogen-bonding network that hold them together will be also discussed. F. Gámez, B. Martínez-Haya, S. Blanco,J. C. López and J. L. Alonso, Phys. Chem. Chem. Phys. 2014, 14 12912-12918 V. A. Shubert, C.W. Müller and T. Zwier, J. Phys. Chem. A 2009, 113 8067-8079

  5. CROWN FUNCTIONALIZED LINEAR POLYSILOXANE PLATINUM COMPLEX AS HYDROSILYLATION CATALYST

    Institute of Scientific and Technical Information of China (English)

    CHEN Yuanyin; LU Xueran; GONG Shuling; ZHANG Baolian

    1994-01-01

    A modified method of preparing crown functionalized linear polysiloxane has been described.4'-allylbenzo-15-crown-5 was subjected to hydrosilylation with methyldichlorosilane,followed by polycondensation with silanol-terminated polydimethylsiloxane to give the title crown functionalized linear polysiloxane. It was found that the polysiloxane could be coordinated with platinum salt to form platinum complex, which could catalyze the hydrosilylation of olefins with triethoxysilane efficiently.

  6. 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.

  7. Complexes of Diquat with Dibenzo-24-Crown-8

    Institute of Scientific and Technical Information of China (English)

    LI Shijun; HUANG Feihe; SLEBODNICK Carla; ASHRAF-KHORASSANI Mehdi; GIBSON Harry W.

    2009-01-01

    The complexation between dibenzo-24-crown-8(1)and diquat(2)was investigated in detail by NMR,MS andlated,in which a single molecule of diquat is enclosed in the concave cavity provided by two dibenzo-24-crown-8 host molecules.Both results are different from the previously assumed stoichiometry of the complexation between dibenzo-24-crown-8 and diquat.This result enriches the range of host-guest complexes based on dibenzo-24crown-8 and provides new opportunities for developing more complicated structures and chemosensors for diquat.

  8. [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.

  9. Biomechanical influence of crown-to-implant ratio on stress distribution over internal hexagon short implant: 3-D finite element analysis with statistical test.

    Science.gov (United States)

    Ramos Verri, Fellippo; Santiago Junior, Joel Ferreira; de Faria Almeida, Daniel Augusto; de Oliveira, Guilherme Bérgamo Brandão; de Souza Batista, Victor Eduardo; Marques Honório, Heitor; Noritomi, Pedro Yoshito; Pellizzer, Eduardo Piza

    2015-01-02

    The study of short implants is relevant to the biomechanics of dental implants, and research on crown increase has implications for the daily clinic. The aim of this study was to analyze the biomechanical interactions of a singular implant-supported prosthesis of different crown heights under vertical and oblique force, using the 3-D finite element method. Six 3-D models were designed with Invesalius 3.0, Rhinoceros 3D 4.0, and Solidworks 2010 software. Each model was constructed with a mandibular segment of bone block, including an implant supporting a screwed metal-ceramic crown. The crown height was set at 10, 12.5, and 15 mm. The applied force was 200 N (axial) and 100 N (oblique). We performed an ANOVA statistical test and Tukey tests; p0.05) under axial load. However, crown heights of 12.5 and 15 mm caused statistically significant damage to the stress distribution of screws and to the cortical bone (p<0.001) under oblique load. High crown to implant (C/I) ratio harmed microstrain distribution on bone tissue under axial and oblique loads (p<0.001). Crown increase was a possible deleterious factor to the screws and to the different regions of bone tissue.

  10. Management and Followup of Complicated Crown Fractures in Young Patients Treated with Partial Pulpotomy

    Directory of Open Access Journals (Sweden)

    Francisco Ojeda-Gutierrez

    2013-01-01

    Full Text Available Two cases of young patients with traumatized permanent teeth having complicated crown fractures are reported. Endodontic management included partial pulpotomy by the Cvek technique; restorative management included resin restoration and reattachment of the teeth fragments. Treatments were considered successful in all cases according to the following criteria: absence of clinical symptoms, absence of X-ray signs of pathology, and presence of pulpal vitality 6 to 25 months after treatment.

  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. Trend of traumatic crown injuries and associated factors in preschool children

    Directory of Open Access Journals (Sweden)

    Bernardo Antonio AGOSTINI

    Full Text Available Abstract The aim of this study was to assess trends in traumatic crown injuries (TCIs, their prevalence, and association with socioeconomic and clinical factors in preschool children over a 5-year period. A series of cross-sectional surveys was conducted in Santa Maria, Brazil, on children attending a National Day of Children’s Vaccination. The same protocol was used in all surveys conducted in 2008, 2010, and 2013. Clinical examinations were performed to evaluate types of traumatic crown injuries using the O’brien index. A semi-structured questionnaire was answered by the parents. It provided information about several socioeconomic factors as well as the parents’ perception of their child’s oral health. The chi-square for trends test was used to verify changes in TCI prevalence throughout the years. The association between socioeconomic and clinical factors with TCI was assessed by the Poisson regression analysis. A total of 1,640 children were examined. The prevalence of TCIs decreased significantly from 2008 to 2013 (10.12%; p < 0.001. Central incisors were the most vulnerable to injury, independent of the year. Moreover, older children and those with inadequate lip coverage were more likely to present with some traumatic dental injury (p < 0.001. prevalence of traumatic crown injuries decreased following the years, however TCI remain an important subject to consider when planning oral health policies.

  15. 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.

  16. Pediatric Preformed Metal Crowns - An Update

    Directory of Open Access Journals (Sweden)

    Sangameshwar Sajjanshetty

    2013-01-01

    Full Text Available Stainless Steel crowns (SSC were introduced in 1947 by the Rocky Mountain Company and popularized by Humphrey in 1950. Prefabricated SSC can be adapted to individual primary teeth and cemented in place to provide a definitive restoration. The SSC is extremely durable, relatively inexpensive, subject to minimal technique sensitivity during placement, and offers the advantage of full coronal coverage. SSC are often used to restore primary and permanent teeth in children and adolescents where intracoronal restorations would otherwise fail. This article brings the update of this definitive restoration.

  17. 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.

  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. Comparison of the fit of cast gold crowns fabricated from the digital and the conventional impression techniques

    Science.gov (United States)

    Jeon, Young-Chan; Jeong, Chang-Mo

    2017-01-01

    PURPOSE The purpose of this study was to compare the fit of cast gold crowns fabricated from the conventional and the digital impression technique. MATERIALS AND METHODS Artificial tooth in a master model and abutment teeth in ten patients were restored with cast gold crowns fabricated from the digital and the conventional impression technique. The forty silicone replicas were cut in three sections; each section was evaluated in nine points. The measurement was carried out by using a measuring microscope and I-Soultion. Data from the silicone replica were analyzed and all tests were performed with α-level of 0.05. RESULTS 1. The average gaps of cast gold crowns fabricated from the digital impression technique were larger than those of the conventional impression technique significantly. 2. In marginal and internal axial gap of cast gold crowns, no statistical differences were found between the two impression techniques. 3. The internal occlusal gaps of cast gold crowns fabricated from the digital impression technique were larger than those of the conventional impression technique significantly. CONCLUSION Both prostheses presented clinically acceptable results with comparing the fit. The prostheses fabricated from the digital impression technique showed more gaps, in respect of occlusal surface. PMID:28243386

  20. Resistance in tomato and wild relatives to crown and root rot caused by Phytophthora capsici.

    Science.gov (United States)

    Quesada-Ocampo, L M; Hausbeck, M K

    2010-06-01

    Phytophthora capsici causes root, crown, and fruit rot of tomato, a major vegetable crop grown worldwide. The objective of this study was to screen tomato cultivars and wild relatives of tomato for resistance to P. capsici. Four P. capsici isolates were individually used to inoculate 6-week-old seedlings (1 g of P. capsici-infested millet seed per 10 g of soilless medium) of 42 tomato cultivars and wild relatives of tomato in a greenhouse. Plants were evaluated daily for wilting and death. All P. capsici isolates tested caused disease in seedlings but some isolates were more pathogenic than others. A wild relative of cultivated tomato, Solanum habrochaites accession LA407, was resistant to all P. capsici isolates tested. Moderate resistance to all isolates was identified in the host genotypes Ha7998, Fla7600, Jolly Elf, and Talladega. P. capsici was frequently recovered from root and crown tissue of symptomatic inoculated seedlings but not from leaf tissue or asymptomatic or control plants. The phenotype of the recovered isolate matched the phenotype of the inoculum. Pathogen presence was confirmed in resistant and moderately resistant tomato genotypes by species-specific polymerase chain reaction of DNA from infected crown and root tissue. Amplified fragment length polymorphisms of tomato genotypes showed a lack of correlation between genetic clusters and susceptibility to P. capsici, indicating that resistance is distributed in several tomato lineages. The results of this study create a baseline for future development of tomato cultivars resistant to P. capsici.

  1. Synthesis and Cation Complexation of Lariat Calix[4 ] crowns

    Institute of Scientific and Technical Information of China (English)

    SHI Zheng-Wei; JIN Chuan-Ming; LU Guo-Yuan

    2003-01-01

    @@ Calixcrowns carrying bridging polyethyleneoxy moieties on the lower rim, which combine calixarene and crown ether in a single molecule, are a novel class of host compounds which have attracted increasing attention because of their increased ability for selective complexation of cations and neutral molecules compared with crown ethers or cal ixarenes.

  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. SILICA-BOUND CROWN ETHERS PLATINUM COMPLEX AS HYDROSILYLATION CATALYST

    Institute of Scientific and Technical Information of China (English)

    CHEN Yuanyin; MENG Lingzhi; LI Liping; LUO Jieqi; HU Jinchang

    1993-01-01

    Silica-bound 15-Crown-5, 18-Crown-6 with a spacer of propyloxymethyl and their platinum complexes have been synthesized. It was found that they were efficient catalysts for the hydrosilylation of olefins with triethoxysilane in the temperature range of 60 to 130 ℃ .

  5. Effect of framework design on crown failure.

    Science.gov (United States)

    Bonfante, Estevam A; da Silva, Nelson R F A; Coelho, Paulo G; Bayardo-González, Daniel E; Thompson, Van P; Bonfante, Gerson

    2009-04-01

    This study evaluated the effect of core-design modification on the characteristic strength and failure modes of glass-infiltrated alumina (In-Ceram) (ICA) compared with porcelain fused to metal (PFM). Premolar crowns of a standard design (PFMs and ICAs) or with a modified framework design (PFMm and ICAm) were fabricated, cemented on dies, and loaded until failure. The crowns were loaded at 0.5 mm min(-1) using a 6.25 mm tungsten-carbide ball at the central fossa. Fracture load values were recorded and fracture analysis of representative samples were evaluated using scanning electron microscopy. Probability Weibull curves with two-sided 90% confidence limits were calculated for each group and a contour plot of the characteristic strength was obtained. Design modification showed an increase in the characteristic strength of the PFMm and ICAm groups, with PFM groups showing higher characteristic strength than ICA groups. The PFMm group showed the highest characteristic strength among all groups. Fracture modes of PFMs and of PFMm frequently reached the core interface at the lingual cusp, whereas ICA exhibited bulk fracture through the alumina core. Core-design modification significantly improved the characteristic strength for PFM and for ICA. The PFM groups demonstrated higher characteristic strength than both ICA groups combined.

  6. Structural Study of Mismatched Disila-Crown Ether Complexes

    Directory of Open Access Journals (Sweden)

    Kirsten Reuter

    2017-02-01

    Full Text Available Mismatched complexes of the alkali metals cations Li+ and Na+ were synthesized from 1,2-disila[18]crown-6 (1 and 2 and of K+ from 1,2,4,5-tetrasila[18]crown-6 (4. In these alkali metal complexes, not all crown ether O atoms participate in the coordination, which depicts the coordination ability of the C-, Si/C-, and Si-bonded O atoms. Furthermore, the inverse case—the coordination of the large Ba2+ ion by the relatively small ligand 1,2-disila[15]crown-5—was investigated, yielding the dinuclear complex 5. This structure represents a first outlook on sandwich complexes based on hybrid crown ethers.

  7. 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.

  8. 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)

  9. 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.

  10. 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.

  11. 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.

  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. Management of a Complicated Crown Fracture in a Tertiary Care Hospital

    Directory of Open Access Journals (Sweden)

    Md Abdul Hannan Sheikh

    2017-01-01

    Full Text Available Restoration of a fractured tooth is routinely performed in clinical practice. Many factors are considered in an effort to provide optimal mechanical properties, aesthetics, longevity as well as patient acceptance. In this type of challenging endeavour, main effort should be made to save as much of the coronal tooth structure to increase survival rate of endodontically-treated teeth. This case report presents a 35-year-old male with an oblique complicated crown fracture of maxillary left central incisor tooth. The procedure used to repair the fracture was gingivectomy followed by endodontic treatment. The root canal was filled with a root canal sealer and gutta-percha points. After root canal obturation, the tooth was restored with a glass fiber post and composite resin without additional crown coverage. The restoration made it possible to maintain the remaining tooth structure in a good occlusion and resulted in a high level of patient satisfaction.

  14. 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.

  15. 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.

  16. 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.

  17. Genotyping of Candida orthopsilosis Clinical Isolates by Amplification Fragment Length Polymorphism Reveals Genetic Diversity among Independent Isolates and Strain Maintenance within Patients▿

    OpenAIRE

    Tavanti, Arianna; Hensgens, Lambert A. M.; Ghelardi, Emilia; Campa, Mario; Senesi, Sonia

    2007-01-01

    Candida parapsilosis former groups II and III have recently been established as independent species named C. orthopsilosis and C. metapsilosis, respectively. In this report, 400 isolates (290 patients) previously classified as C. parapsilosis by conventional laboratory tests were screened by BanI digestion profile analysis of the secondary alcohol dehydrogenase gene fragment and by amplification fragment length polymorphism (AFLP). Thirty-three strains collected from 13 patients were identifi...

  18. 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.

  19. Determination of physical height from crown dimensions of deciduous tooth: A dental morphometric study

    Directory of Open Access Journals (Sweden)

    C Ramanna

    2016-01-01

    Full Text Available Background: Dental morphometrics is a subject of great significance in forensic odontology in identification of an individual. Use of teeth to represent a physical profile is valuable for identification of an individual. Aims and Objectives: The present study aims to assess the clinical crown length (CL of erupted deciduous teeth and height of the child. A correlation of these parameters was attempted to arrive at a mathematical equation which would formulate a ratio of tooth CL to individual height that would support in estimating the probable height of the child. Materials and Methods: About 60 children (30 males and 30 females of age ranged from 3–6 years were included in this study. Clinical vertical CLs of the deciduous dentition (tooth numbers 51, 52, 53, 54, and 55 were calculated using digital Vernier calipers (Aerospace Ltd., Bengaluru, Karnataka, India on the cast models. Child height was measured using a standard measuring tape. Ratios of deciduous CL to height of the child were recorded. Linear stepwise forward regression analysis was applied to predict the probability of CL of a tooth most likely to support in prediction of physical height of the child. Results: Tabulated results showed a probable correlation between tooth CL and height of the child. Tooth CLs of deciduous upper right second molar (55 among the males, lateral incisor (52 among females, and canine (53 using the combined male and female data were statistically significant, and they approximately predicted the child height with minimal variations. Mathematically derived equations based on linear stepwise forward regression analysis using sixty children data are height prediction (derived from combined data of male and female children = 400.558 + 90.264 (53 CL, male child height prediction (derived from data of male children = 660.290 + 72.970 (55 CL, and female child height prediction (derived from data of female children = −187.942 + 194.818 (52 CL. Conclusion: In

  20. Earliest known crown-group salamanders.

    Science.gov (United States)

    Gao, Ke-Qin; Shubin, Neil H

    2003-03-27

    Salamanders are a model system for studying the rates and patterns of the evolution of new anatomical structures. Recent discoveries of abundant Late Jurassic and Early Cretaceous salamanders are helping to address these issues. Here we report the discovery of well-preserved Middle Jurassic salamanders from China, which constitutes the earliest known record of crown-group urodeles (living salamanders and their closest relatives). The new specimens are from the volcanic deposits of the Jiulongshan Formation (Bathonian), Inner Mongolia, China, and represent basal members of the Cryptobranchidae, a family that includes the endangered Asian giant salamander (Andrias) and the North American hellbender (Cryptobranchus). These fossils document a Mesozoic record of the Cryptobranchidae, predating the previous record of the group by some 100 million years. This discovery provides evidence to support the hypothesis that the divergence of the Cryptobranchidae from the Hynobiidae had taken place in Asia before the Middle Jurassic period.

  1. 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...

  2. [Restoration of composite on etched stainless steel crowns. (1)].

    Science.gov (United States)

    Goto, G; Zang, Y; Hosoya, Y

    1990-01-01

    Object of investigation The retention of composite resin to etched stainless steel crowns was tested as a possible method for restoring primary anterior teeth. Method employed 1) SEM observation Stainless steel crowns (Sankin Manufacture Co.) were etched with an aqua resia to create surface roughness and undercut to retain the composite resin to the crowns. Etching times were 1, 2, 3, 5, 8, 10 and 20 minutes, then washed in a 70% alcohol solution using an ultrasonic washer and dried. A total of 96 etched samples and non etched control samples were observed through the scanning electron microscope (Hitachi 520). 2) Shear bond strength test Stainless steel crowns were etched in an aqua resia from 1 to 20 minutes, then washed and dried. Composite resin (Photo Clearfil A, Kuraray Co.) with the bonding agent was placed on the crowns and the shear bond strength was tested in 56 samples using an Autograph (DCS-500, Shimazu). Results 1) SEM observation showed that the etching surface of stainless steel crowns created surface roughness and undercut. The most desirable surface was obtained in the 3 to 5 minute etching time specimens. 2) The highest bond strength was obtained in a 3 minute etching specimen. It was 42.12 MPa, although 29.26 MPa in mean value. Conclusion Etching with an aqua resia increased the adherence of composite resin to the surface of stainless steel crowns.

  3. 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.

  4. 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

  5. Survival Predictions of Ceramic Crowns Using Statistical Fracture Mechanics.

    Science.gov (United States)

    Nasrin, S; Katsube, N; Seghi, R R; Rokhlin, S I

    2017-01-01

    This work establishes a survival probability methodology for interface-initiated fatigue failures of monolithic ceramic crowns under simulated masticatory loading. A complete 3-dimensional (3D) finite element analysis model of a minimally reduced molar crown was developed using commercially available hardware and software. Estimates of material surface flaw distributions and fatigue parameters for 3 reinforced glass-ceramics (fluormica [FM], leucite [LR], and lithium disilicate [LD]) and a dense sintered yttrium-stabilized zirconia (YZ) were obtained from the literature and incorporated into the model. Utilizing the proposed fracture mechanics-based model, crown survival probability as a function of loading cycles was obtained from simulations performed on the 4 ceramic materials utilizing identical crown geometries and loading conditions. The weaker ceramic materials (FM and LR) resulted in lower survival rates than the more recently developed higher-strength ceramic materials (LD and YZ). The simulated 10-y survival rate of crowns fabricated from YZ was only slightly better than those fabricated from LD. In addition, 2 of the model crown systems (FM and LD) were expanded to determine regional-dependent failure probabilities. This analysis predicted that the LD-based crowns were more likely to fail from fractures initiating from margin areas, whereas the FM-based crowns showed a slightly higher probability of failure from fractures initiating from the occlusal table below the contact areas. These 2 predicted fracture initiation locations have some agreement with reported fractographic analyses of failed crowns. In this model, we considered the maximum tensile stress tangential to the interfacial surface, as opposed to the more universally reported maximum principal stress, because it more directly impacts crack propagation. While the accuracy of these predictions needs to be experimentally verified, the model can provide a fundamental understanding of the

  6. Cone-beam computed tomography for the assessment of root–crown ratios of the maxillary and mandibular incisors in a Korean population

    Science.gov (United States)

    Choi, Sung-Hwan; Kim, Jung-Suk; Kim, Cheol-Soon; Yu, Hyung-Seog

    2017-01-01

    Objective This retrospective, cross-sectional study aimed to establish reference data for normal crown and root lengths and the root–crown ratios (R/C ratios) for the mature maxillary and mandibular incisors in a Korean population by using cone-beam computed tomography (CBCT). Methods We included 672 Korean patients (141 men and 531 women; mean age, 27.2 ± 7.7 years) who underwent CBCT examinations during various dental treatments. Crown and root lengths and the R/C ratios of the maxillary and mandibular incisors were measured using CBCT data, which were analyzed to detect significant differences between demographic factors as well as sagittal and vertical skeletal or occlusal relationships. Results Teeth of the same type in each half-arch were symmetrical. The mean R/C ratios varied from 1.1 to 1.2 for the maxillary incisors and from 1.3 to 1.4 for the mandibular incisors. Crown and root lengths were greater in men than in women, regardless of tooth type. Root lengths and R/C ratios for the mandibular incisors were significantly greater in patients with skeletal Class II malocclusion or an excessive overjet than in the other patients. The R/C ratios for the mandibular incisors were lower in patients with an open bite than in those with a normal or deep bite. Moreover, the R/C ratios for the mandibular incisors increased with age. Conclusions The data obtained in our study can serve as reference values for crown and root lengths and the R/C ratios for the maxillary and mandibular incisors in the Korean population. PMID:28127538

  7. 肯尼迪病临床特征与CAG重复序列数目关系分析%The clinical features of Kennedy disease and the correlation between clinical features and length of CAG re-peats

    Institute of Scientific and Technical Information of China (English)

    何炳接; 何若洁; 石磊; 叶城辉; 戴佳颖; 梁银杏; 卢锡林; 姚晓黎

    2015-01-01

    had family history. Clinical features included medulla oblongata and spinal muscular atrophy and weakness, limbs tremor, perioral muscles twitch and endocrine function and metabolic disorders in some cases. Creatine kinase, triglyceride, low density lipoprotein, follicle estrogen and prolactin were significantly in⁃creased compared to healthy adults (P:0.000,0.018,0.000,0.000,0.003). The number of CAG repeat was negatively correlated with the onset age (r=-0.549, P=0.001) but not associated with the illness severity (ALS rating scale) (r=0.001, P=0.998). ALS score was negatively correlated with course of disease(r=-0.540, P=0.001).Conclusions Chinese KD pa⁃ tients share similar clinical phenotypes with those of other races but exhibit slightly different clinical characteristics. The length of the CAG repeat influences age at onset but not the severity of disease. Severity of disease is related to the course of disease.

  8. 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.

  9. Achieving optimal outcomes with all-zirconia crowns.

    Science.gov (United States)

    Christensen, John Juel

    2014-01-01

    All-zirconia crowns are enjoying an unprecedented popularity. Dental laboratories are acquiring new equipment and adopting novel techniques, some of which require a learning curve. As a result, some crowns fabricated by computer-aided design/computer-aided manufacturing technology may come back to the dentist with unsatisfactory features. Dentists should carefully examine each crown under magnification prior to delivery to the patient. The dentist and dental laboratory should establish a close partnership with clear communication to yield the most favorable outcome for the patient.

  10. 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

  11. 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.

  12. 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.

  13. 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.

  14. Implant-supported fixed dental prostheses with CAD/CAM-fabricated porcelain crown and zirconia-based framework.

    Science.gov (United States)

    Takaba, Masayuki; Tanaka, Shinpei; Ishiura, Yuichi; Baba, Kazuyoshi

    2013-07-01

    Recently, fixed dental prostheses (FDPs) with a hybrid structure of CAD/CAM porcelain crowns adhered to a CAD/CAM zirconia framework (PAZ) have been developed. The aim of this report was to describe the clinical application of a newly developed implant-supported FDP fabrication system, which uses PAZ, and to evaluate the outcome after a maximum application period of 36 months. Implants were placed in three patients with edentulous areas in either the maxilla or mandible. After the implant fixtures had successfully integrated with bone, gold-platinum alloy or zirconia custom abutments were first fabricated. Zirconia framework wax-up was performed on the custom abutments, and the CAD/CAM zirconia framework was prepared using the CAD/CAM system. Next, wax-up was performed on working models for porcelain crown fabrication, and CAD/CAM porcelain crowns were fabricated. The CAD/CAM zirconia frameworks and CAD/CAM porcelain crowns were bonded using adhesive resin cement, and the PAZ was cemented. Cementation of the implant superstructure improved the esthetics and masticatory efficiency in all patients. No undesirable outcomes, such as superstructure chipping, stomatognathic dysfunction, or periimplant bone resorption, were observed in any of the patients. PAZ may be a potential solution for ceramic-related clinical problems such as chipping and fracture and associated complicated repair procedures in implant-supported FDPs.

  15. 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.

  16. 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.

  17. A photoelastic assessment of residual stresses in zirconia-veneer crowns.

    Science.gov (United States)

    Belli, R; Monteiro, S; Baratieri, L N; Katte, H; Petschelt, A; Lohbauer, U

    2012-03-01

    Residual stresses within the veneer are linked to the high prevalence of veneer chipping observed in clinical trials of zirconia prostheses. We hypothesized that the thermal mismatch between the zirconia infrastructure and the veneer porcelain, as well as the rate used for cooling zirconia-veneer crowns, would be directly proportional to the magnitude of residual stresses built within the veneer layer. Two porcelains with different coefficients of thermal expansion were used to veneer zirconia copings, to create high or low thermal mismatches. The crowns were cooled according to a fast- or a slow-cooling protocol. The retardation of polarized light waves was used to calculate the residual stress magnitude and distribution across the veneer, according to the photoelasticity principle, in 1.0-mm-thick crown sections. While thermal mismatch was an important factor influencing the maximum stress development in the veneer, cooling rate had a minor role. Curved surfaces were preferential sites for stress concentration regardless of thermal mismatch or cooling rate.

  18. 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.

  19. 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.

  20. 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.

  1. 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...

  2. Acetylene–ammonia–18-crown-6 (1/2/1

    Directory of Open Access Journals (Sweden)

    Tobias Grassl

    2012-10-01

    Full Text Available The title compound, C2H2·C12H24O6·2NH3, was formed by co-crystallization of 18-crown-6 and acetylene in liquid ammonia. The 18-crown-6 molecule has threefold rotoinversion symmetry. The acteylene molecule lies on the threefold axis and the whole molecule is generated by an inversion center. The two ammonia molecules are also located on the threefold axis and are related by inversion symmetry. In the crystal, the ammonia molecules are located below and above the crown ether plane and are connected by intermolecular N—H...O hydrogen bonds. The acetylene molecules are additionally linked by weak C—H...N interactions into chains that propagate in the direction of the crystallographic c axis. The 18-crown-6 molecule [occupancy ratio 0.830 (4:0.170 (4] is disordered and was refined using a split model.

  3. 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.

  4. Failure Probability of Three Designs of Zirconia Crowns.

    Science.gov (United States)

    Ramos, Gabriela Freitas; Monteiro, Evelyn Barbosa; Bottino, Marco Antonio; Zhang, Yu; Marques de Melo, Renata

    2015-01-01

    This study used a two-parameter Weibull analysis for evaluation of the lifespan of fully or partially porcelain-/glaze-veneered zirconia crowns after fatigue test. A sample of 60 first molars were selected and prepared for full-coverage crowns with three different designs (n = 20): traditional (crowns with zirconia framework covered with feldspathic porcelain), modified (crowns partially covered with veneering porcelain), and monolithic (full-contour zirconia crowns). All specimens were treated with a glaze layer. Specimens were subjected to mechanical cycling (100 N, 3 Hz) with a piston with a hemispherical tip (Ø = 6 mm) until the specimens failed or up to 2 × 10⁶ cycles. Every 500,000 cycles, the fatigue tests were interrupted and stereomicroscopy (10×) was used to inspect the specimens for damage. The authors performed Weibull analysis of interval data to calculate the number of failures in each interval. The types and numbers of failures according to the groups were: cracking (13 traditional, 6 modified) and chipping (4 traditional) of the feldspathic porcelain, followed by delamination (1 traditional) at the veneer/core interface and debonding (2 monolithic) at the cementation interface. Weibull parameters (β, scale; η, shape), with a two-sided confidence interval of 95%, were: traditional-1.25 and 0.9 × 10⁶ cycles; modified-0.58 and 11.7 × 10⁶ cycles; and monolithic-1.05 and 16.5 × 10⁶ cycles. Traditional crowns showed greater susceptibility to fatigue, the modified group presented higher propensity to early failures, and the monolithic group showed no susceptibility to fatigue. The modified and monolithic groups presented the highest number of crowns with no failures after the fatigue test. The three crown designs presented significantly different behaviors under fatigue. The modified and monolithic groups presented less probability of failure after 2 × 10⁶ cycles.

  5. 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.

  6. Crown lengthening procedure in the management of amelogenesis imperfecta

    OpenAIRE

    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 s...

  7. Polymorph of dibenzo-24-crown-8 and its mercury complex

    OpenAIRE

    Crochet, Aurélien; Kottelat, Emmanuel; Fleury, Antoine; Neuburger, Markus; Fromm, Katharina M.

    2011-01-01

    Dibenzo-24-crown-8 is studied herein as a flexible ligand able to adopt different conformations, as well as for the complexation of mercury. The recrystallization of dibenzo-24-crown-8 (DB24C8) from dry THF gives a new polymorphic structure of this ligand. This new structure is described and compared to the literature compound. Additionally, coordination of this ligand to mercury iodide HgI₂ is studied.

  8. 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.

  9. 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。

  10. 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...

  11. 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.

  12. 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.

  13. 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.

  14. The energetic characterization of pineapple crown leaves.

    Science.gov (United States)

    Braga, R M; Queiroga, T S; Calixto, G Q; Almeida, H N; Melo, D M A; Melo, M A F; Freitas, J C O; Curbelo, F D S

    2015-12-01

    Energetic characterization of biomass allows for assessing its energy potential for application in different conversion processes into energy. The objective of this study is to physicochemically characterize pineapple crown leaves (PC) for their application in energy conversion processes. PC was characterized according to ASTM E871-82, E1755-01, and E873-82 for determination of moisture, ash, and volatile matter, respectively; the fixed carbon was calculated by difference. Higher heating value was determined by ASTM E711-87 and ash chemical composition was determined by XRF. The thermogravimetric and FTIR analyses were performed to evaluate the thermal decomposition and identify the main functional groups of biomass. PC has potential for application in thermochemical processes, showing high volatile matter (89.5%), bulk density (420.8 kg/m(3)), and higher heating value (18.9 MJ/kg). The results show its energy potential justifying application of this agricultural waste into energy conversion processes, implementing sustainability in the production, and reducing the environmental liabilities caused by its disposal.

  15. Suitability of Secondary PEEK Telescopic Crowns on Zirconia Primary Crowns: The Influence of Fabrication Method and Taper

    Directory of Open Access Journals (Sweden)

    Susanne Merk

    2016-11-01

    Full Text Available This study investigates the retention load (RL between ZrO2 primary crowns and secondary polyetheretherketone (PEEK crowns made by different fabrication methods with three different tapers. Standardized primary ZrO2 crowns were fabricated with three different tapers: 0°, 1°, and 2° (n = 10/group. Ten secondary crowns were fabricated (i milled from breCam BioHPP blanks (PM; (ii pressed from industrially fabricated PEEK pellets (PP (BioHPP Pellet; or (iii pressed from granular PEEK (PG (BioHPP Granulat. One calibrated operator adjusted all crowns. In total, the RL of 90 secondary crowns were measured in pull-off tests at 50 mm/min, and each specimen was tested 20 times. Two- and one-way ANOVAs followed by a Scheffé’s post-hoc test were used for data analysis (p < 0.05. Within crowns with a 0° taper, the PP group showed significantly higher retention load values compared with the other groups. Among the 1° taper, the PM group presented significantly lower retention loads than the PP group. However, the pressing type had no impact on the results. Within the 2° taper, the fabrication method had no influence on the RL. Within the PM group, the 2° taper showed significantly higher retention load compared with the 1° taper. The taper with 0° was in the same range value as the 1° and 2° tapers. No impact of the taper on the retention value was observed between the PP groups. Within the PG groups, the 0° taper presented significantly lower RL than the 1° taper, whereas the 2° taper showed no differences. The fabrication method of the secondary PEEK crowns and taper angles showed no consistent effect within all tested groups.

  16. 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

  17. 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.

  18. Composite crown-form crowns for severely decayed primary molars: a technique for restoring function and esthetics.

    Science.gov (United States)

    Ram, D; Peretz, B

    2000-01-01

    Current developments in esthetic dentistry center around new techniques and materials that improve the ability of the clinician to provide esthetic services. This article describes a step-by-step method of placing composite crown-form crowns on severely decayed primary mandibular molars. The described technique allows for restoring, as close as possible, form and function lost to caries in an esthetic mode in cases of severely decayed primary molars that would have required stainless steel crowns had they been treated traditionally. Disadvantages of this treatment mode are that dryness may not be prevented in the proximal margins, especially where subgingival carious involvement is encountered and the margin areas may be contaminated with gingival fluid or blood. Although no long-term follow-up has been reported for the technique, when strong opposition by the parent or child to the stainless steel crown is encountered, and a desire for esthetic restoration is strongly expressed, the composite crown-form crowns may be considered as an alternative.

  19. 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

  20. 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

  1. A prospective study of leukocyte telomere length and risk of phobic anxiety among women.

    Science.gov (United States)

    Ramin, Cody; Wang, Wei; Prescott, Jennifer; Rosner, Bernard; Simon, Naomi M; De Vivo, Immaculata; Okereke, Olivia I

    2015-12-15

    We prospectively examined the relation of relative telomere lengths (RTLs), a marker of biological aging, to phobic anxiety in later-life. RTLs in peripheral blood leukocytes were measured among 3194 women in the Nurses' Health Study who provided blood samples in 1989/90. The Crown-Crisp Phobic Index (CCI, range=0–16) was assessed in 1988 and 2004. Only participants with CCI≤3 (consistent with no meaningful anxiety symptoms) in 1988 were included. We related baseline RTLs to odds ratios (ORs) of incident high phobic anxiety symptoms (CCI≥6). To enhance clinical relevance, we used finite mixture modeling (FMM) to relate baseline RTLs to latent classes of CCI in 2004. RTLs were not significantly associated with high phobic anxiety symptoms after 16 years of follow-up. However, FMM identified 3 groups of phobic symptoms in later-life: severe, minimal/intermediate, and non-anxious. The severe group had non-significantly shorter multivariable-adjusted mean RTLs than the minimal/intermediate and non-anxious groups. Women with shorter telomeres vs. longest telomeres had non-significantly higher likelihood of being in the severe vs. non-anxious group. Overall, there was no significant association between RTLs and incident phobic anxiety symptoms. Further work is required to explore potential connections of telomere length and emergence of severe phobic anxiety symptoms during later-life.

  2. Aesthetic effect of zirconia crown on the anterior tooth%二氧化锆全瓷冠在前牙美容修复中的应用

    Institute of Scientific and Technical Information of China (English)

    邓薇; 杨永进; 蔡兴伟; 张娜; 李颖华; 郑创益

    2011-01-01

    Objective: To investigate the clinical results ofzirconia crown on the anterior tooth. Methods: All 58 patients treated with porcelain-veneered zirconia single crowns for 86 anterior teeth. After 12 months follow up. Results: The clinical outcome of the 86 all-ceramic zirconia crowns at a rank A in all five aspects between 0-6 months (100%), only one zirconia single crowns in marginal fitness (97.6%) and the situation ofgingival (97.6%) at rank B and C after 12 months follow up. Conclusion: Porcelain-veneered zirconia single crown contribute to the aesthetic effect of the anterior teeth.%目的:探讨二氧化锆全瓷冠在前牙美容修复的应用.方法:选择58例患者的86颗前牙,二氧化锆全瓷冠修复,观察1年.结果:86颗二氧化锆全瓷冠在修复完成第1天及6个月五项评价指标均达到A级(100%),12个月边缘完整性(97.6%)和牙龈状况 (97.6%)达到B、C级各1例.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.

  3. Combining monolithic zirconia crowns, digital impressioning, and regenerative cement for a predictable restorative alternative to PFM.

    Science.gov (United States)

    Griffin, Jack D

    2013-03-01

    Advances in indirect esthetic materials in recent years have provided the dental profession higher levels of strength and esthetics than ever before with products like lithium disilicate and zirconium oxide. Providing excellent fit and versatile performance, and because there is no porcelain to delaminate, chip, or fracture, monolithic zirconia crowns have the potential to outperform other layered restorations such as porcelain-fused-to-metal (PFM). This review of monolithic zirconia highlights a clinical case in which all-zirconia restorations were combined with CAD/CAM technology for a successful esthetic restorative outcome.

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

    DEFF Research Database (Denmark)

    Hosseini, Mandana

    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...... 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...

  5. Coronas implantosoportadas: ¿individualizar o ferulizar? Implant-supported crowns: Individualized or splinting?

    Directory of Open Access Journals (Sweden)

    M Gómez Polo

    2007-04-01

    Full Text Available Existen diferentes formas de rehabilitación de coronas sobre implantes adyacentes en un tramo edéntulo. Las opciones que pueden encontrarse son la de restaurar con varias coronas unitarias, o bien unir esas coronas en una sola prótesis. Material y Método: Se llevó a cabo una búsqueda bibliográfica a través de bases de datos en revistas especializadas de Odontología. Resultados: En la bibliografía revisada se observa que existen defensores y detractores de cada una de las técnicas, basándose cada autor en distintos estudios y argumentos. Discusión: Se encontraron ventajas e inconvenientes en ambas opciones prostodóncicas, valorando en base a éstos cuándo utilizar cada una de las técnicas propuestas. Conclusiones: Cuando las condiciones son idóneas, se considera adecuada la restauración con coronas individuales; por otro lado cuando existan condiciones adversas (implantes cortos, hueso de mala calidad, carga inmediata o factores oclusales no adecuados, en las que el reparto de fuerzas pueda comprometer el pronóstico de la restauración, la ferulización será el tratamiento de elección.There are different methods of crown rehabilitation refering to implants adjacent in edentulous sites. The options can be: rehabilitation with several single crowns or the splinting of the crowns in the prostheses. Material and method: A bibliographical research through the data base of the U.C.M. library and a review of clinical files of patients treated under the title implant-prostheses has been carried out. Results: There are supporters and non-supporters of each technique, based on different arguments and studies. Discussion: Advantages and inconvenients have been found in each method, taking these into consideration when it comes to using the appropriate restoration. Conclusions: When conditions are suitable, the implants can be restored by using single crowns. On the other hand, when there are no ideal factors (short implants, low bone

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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

  11. 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.

  12. 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

  13. 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.

  14. 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......This paper evaluates the validity of a simple one-dimensional dynamic analysis as well as a Finite-Element model to determine the sliding of a rubble-mound breakwater crown-wall. The evaluation is based on a case example with real wave load time-series and displacements measured from two...... of the accumulated sliding distance of crown-wall superstructures, which is in contrast to findings from previous similar studies on caisson breakwaters. The calculated sliding distance is approximately three times larger than the measured one when using the original one-dimensional model suggested in previous...

  15. Crowned odontoid process and osteoarthrosis of the anterior atlantoaxial joint

    Energy Technology Data Exchange (ETDEWEB)

    Skaane, P.; Klott, K.J.

    1981-01-01

    Crowned odontoid process and osteoarthrosis of the anterior atlantoaxial joint. The so-called peridentale aureole ( crowned odontoid ), a horseshoelike calcification around the odontoid process, can occasionally be shown on transbuccal views of the occipito-atlantoaxial region, but is commonly only seen on a.p. tomography in patients with osteoarthrosis of the anterior atlantoxial joint. Tomographic examinations reveal that these irregular horseshoe-like calcifications around the odontoid peg represent mainly the osteophyte formation on the superior border of the anterior arch of the atlas. These calcifications are often surrounding a smaller calcification on the tip of the odontoid peg sometimes with a bucket-handle appearance corresponding to the ostephyte formation on the odontoid process. The peridentale aureole or crowned odontoid process is easily overlooked unless tomography is performed, and misinterpretations are possible if the radiologist is not familiar with this appearance of osteoarthrosis and some other joint diseases of the anterior atlantoaxial joint.

  16. Chipping resistance of graded zirconia ceramics for dental crowns.

    Science.gov (United States)

    Zhang, Y; Chai, H; Lee, J J-W; Lawn, B R

    2012-03-01

    A serious drawback of veneering porcelains is a pronounced susceptibility to chipping. Glass-infiltrated dense zirconia structures can now be produced with esthetic quality, making them an attractive alternative. In this study, we examined the hypothesis that such infiltrated structures are much more chip-resistant than conventional porcelains, and at least as chip-resistant as non-infiltrated zirconia. A sharp indenter was used to produce chips in flat and anatomically correct glass-infiltrated zirconia crown materials, and critical loads were measured as a function of distance from the specimen edge (flat) or side wall (crown). Control data were obtained on zirconia specimens without infiltration and on crowns veneered with porcelains. The results confirmed that the resistance to chipping in graded zirconia is more than 4 times higher than that of porcelain-veneered zirconia and is at least as high as that of non-veneered zirconia.

  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 zirconia-based crowns decreased the fracture load.

  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. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  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. Crowning glory: public law, power and the monarchy

    OpenAIRE

    Murphy, Thérèse; Whitty, Noel

    2000-01-01

    ‘New public law’ has a keen interest in the deployment of power and the shifting nature of the public and private. In this article, we argue that the historical legacy of the Crown has hindered the ability of public lawyers to respond to changes in modes of governance in the UK. The constitutional law textbook tradition has played a key role in limiting critiques of the Crown because of the obfuscation that surrounds the legal and political status of the Monarch. However, instead of discounti...

  6. 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.

  7. 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

  8. Reactions of 15-crown-5 and bis-15-crown-5 ethers with metal acetylacetonate ions in the gas phase

    Energy Technology Data Exchange (ETDEWEB)

    Timofeev, O.S.; Bogatskii, A.V.; Gren, A.I.; Lobach, A.V.; Nekarsov, Y.S.; Zagorevskii, D.V.

    1985-05-20

    A study was carried out on the ion-molecule reactions of ions arising in the dissociation of ferric, cobaltic, chromic, manganous, neodymium(II), gallium(III), and indium(III) acetylacetonates upon electron impact with 15-crown-5 and bis-15-crown-5. The ratio of the yields of (acac)x-1 /SUP M+L/ ions is determined by the case of reduction of M /SUP x+1+/ to M /SUP x+/ and for (acac)/sub 3/M complexes, this ratio decreases in the series Nd, In, GA > Cr > Fe, Co. The rate constant for the formation of acacCoL/sup +/ ions is greater than for acacFeL/sup +/ ions. The possibility of fixing transition metals in unstable oxidation states by crown ethers is demonstrated in the case of nickel.

  9. Shading of ceramic crowns using digital tooth shade matching devices.

    Science.gov (United States)

    Baltzer, A; Kaufmann-Jinoian, V

    2005-04-01

    In the 1990s, there was great optimism due to the development of devices for measuring tooth shade. The frequently not so simple, visual determination of the shade of a tooth was to be done with the aid of a device which recognizes the shade and describes it accurately by reference to a color chart. However, the skepticism towards such devices was also great. It is known that the color effect frequently differs strongly when comparing a tooth from the shade guide with a metal ceramic crown, despite identical shade designation. Anyone who considers visual shade determination to be inadequate and places his hopes in digital shade matching devices will be disappointed. It is the shade-generating structures of the metal ceramic and frequently of the veneer layers that turn out to be too thin which, despite correct shade selection, cause a different color perception. Such problems have been reduced decisively with the development of fracture-proof hard porcelain caps (Vita In-Ceram) with optical characteristics similar to teeth. In addition, the Vita System 3D-Master tooth shade system developed in 1998 by Vita in cooperation with Dr. Hall from Australia, leads the practitioner to a better understanding of the primary tooth shade characteristics of "brightness (value)", "color intensity (chroma)" and "color (wave length of the visible light, hue)". These two innovations allow a more accurate estimate of the basic shade of a natural tooth (reference tooth) and the imitation in the laboratory of its natural, shade-generating structures. If digital shade measurement supplements the visual shade estimate, then a further improvement can be expected--especially in the recognition of the basic shade. Qualitative descriptions of subjective shade measurement of a natural tooth and of its imitation in the dental laboratory by ceramics can be found frequently in professional journals and publications. With digital tooth shade matching devices, which apart from the color code of

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

    Science.gov (United States)

    MARTINS, Leandro Moura; LORENZONI, Fabio Cesar; de MELO, Alcides Oliveira; da SILVA, Luciana Mendonça; de OLIVEIRA, José Luiz G.; de OLIVEIRA, Pedro Cesar Garcia; BONFANTE, Gerson

    2012-01-01

    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. PMID:22666843

  11. 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.

  12. 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 crystallization exceeded 120 μm, which is the clinically acceptable threshold.

  13. Dioxygen affinities and catalytic oxidation activities of cobalt complexes with Schiff bases containing crown ether

    NARCIS (Netherlands)

    Sun, B.; Chen, J.R.; Hu, J.Y.; Li, X.J.

    2006-01-01

    The stoichiometry of dioxygen uptake of Co complexes with 4',5'-bis-(5-chloro-2-hydroxyphenylmethylideneimino)benzo-12-crown-4 (la), 4',5'-bis(2-hydroxyphenylmethylideneimino)benzo-12-crown-4(1b), 4',5'-bis-(5-methoxy-2-hydroxyphenylmethylideneimino)benzo-12-crown-4 (1c), 4',5'-bis-(5-chloro-2-hydro

  14. Fracture Strength of Aged Monolithic and Bilayer Zirconia-Based Crowns.

    Science.gov (United States)

    Lameira, Deborah Pacheco; Buarque e Silva, Wilkens Aurélio; Andrade e Silva, Frederico; De Souza, Grace M

    2015-01-01

    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.

  15. Comparison of repair methods for ceramic-fused-to-metal crowns

    NARCIS (Netherlands)

    Ozcan, M.; Van Der Sleen, J.M.; Kurunmaki, H.; Vallittu, P.K.

    2006-01-01

    Purpose: The objective of this study was to evaluate the effect of four repair methods on the fracture load of repaired ceramic-fused-to-metal crowns. Materials and Methods: Metal-ceramic crowns were fractured, and the failure load was measured. The fractured metal-ceramic crowns (n = 9) were assign

  16. 18-Crown[6]ether functionalized reduced graphene oxide for membrane-free ion selective sensing

    DEFF Research Database (Denmark)

    Olsen, Gunnar; Ulstrup, Jens; Chi, Qijin

    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...

  17. First report of Fusarium hostae causing crown rot of wheat (Triticum spp.) in Turkey

    Science.gov (United States)

    Crown rot disease of wheat is caused by a complex of Fusarium species. To identify species associated with crown rot in Turkey, crowns and stems of bread wheat (Triticum aestivum L.) and durum wheat (T. durum Desf.) were collected from the Central and Southeast Anatolia, Black Sea, Aegean, Mediterr...

  18. 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.

  19. 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-

  20. 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.

  1. Stars and Nebulae in the Southern Crown

    Science.gov (United States)

    2000-10-01

    The R Coronae Australis complex of young stars and interstellar gas clouds is one of the nearest star-forming regions, at a distance of approx. 500 light-years from the Sun. It is seen in the southern constellation of that name (The "Southern Crown"). Images of this sky area were recently obtained with the Wide Field Imager (WFI) , a 67-million pixel digital camera that is installed at the 2.2-m MPG/ESO Telescope at ESO's La Silla Observatory. Some of these exposures have been combined into a magnificent colour image, here reproduced as PR Photo 25a/00 . The field shown measures about 4.7 x 4.7 light-years 2. It displays the central part of the complex, its brightest stars, and the nebulosity that they illuminate. The interstellar clouds that are associated with the complex are visible all across this field and also beyond its borders (on other exposures), due to the obscuring effect of the dust particles that "dim" the light of stars behind these clouds. This effect is particularly noticeable in the lower left corner where very few stars are seen. R Coronae Australis , the bright star from which the entire complex is named, is located at the center of the field and illuminates the reddish nebula around it. The bright star in the lower part, illuminating a somewhat bluer nebula, is known as TY Coronae Australis . The brightness of these two stars and several others in the same field is variable. They belong to the so-called "T Tauri" class , a type that is quite common in star-forming regions. T Tauri stars are in the early stages of stellar evolution and display various observable characteristics of this phase, e.g. emission at visible and infrared wavelengths due to the accretion of matter left over from their formation, as well as X-ray emission. The nebulosity seen in this picture is mostly due to reflection of the stellar light by small dust particles. The stars in the R Coronae Australis complex do not emit sufficient ultraviolet light to ionize a substantial

  2. 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

  3. Material choice for restorative dentistry: inlays, onlays, crowns, and bridges.

    Science.gov (United States)

    Small, Bruce W

    2006-01-01

    New materials--specifically the new CAD/CAM zirconia-based systems--are available now for restorative dentistry. When esthetics are not a factor, gold remains the standard, particularly for intracoronal restorations and full posterior coverage. Tooth-colored crowns made with zirconia are new and offer great promise for the future, although more long-term in vivo studies are necessary.

  4. 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

  5. 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.

  6. Analysis of "Babar Loses His Crown." Technical Report No. 169.

    Science.gov (United States)

    Green, G. M.; And Others

    This report presents the text analysis of "Babar Loses His Crown," a story for beginning readers. (The techniques used in arriving at the analysis are presented in a Reading Center Technical Report, Number 168, "Problems and Techniques of Text Analysis.") Tables are given for a statistical lexical analysis and for a syntactic…

  7. 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.

  8. Laser pediatric crowns performed without anesthesia: a contemporary technique.

    Science.gov (United States)

    Jacboson, B; Berger, J; Kravitz, R; Patel, P

    2003-01-01

    Extensive caries resulting in the need for a stainless steel crown in primary teeth may now be prepared with the use of the WaterlaseTM YSGG Laser, (Biolase) hard and soft-tissue laser. The use of the laser eliminates the need for local anesthesia, thereby providing optimal patient comfort and compliance.

  9. 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

  10. 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.

  11. Minimum Length - Maximum Velocity

    CERN Document Server

    Panes, Boris

    2011-01-01

    We study a framework where the hypothesis of a minimum length in space-time is complemented with the notion of reference frame invariance. It turns out natural to interpret the action of the obtained reference frame transformations in the context of doubly special relativity. As a consequence of this formalism we find interesting connections between the minimum length properties and the modified velocity-energy relation for ultra-relativistic particles. For example we can predict the ratio between the minimum lengths in space and time using the results from OPERA about superluminal neutrinos.

  12. Crown-root fracture with pulp exposure: a case report with 16-year follow-up.

    Science.gov (United States)

    Moura, Lucia Fatima Almeida de Deus; Leao, Valeria Leopoldino de Area; de Moura, Marcoeli Silva; de Moura, Carmem Dolores Vilarinho Soares; Goncalves, Alessandro Ribeiro; Lima, Cacilda Castelo Branco; de Lima, Marina de Deus Moura

    2015-01-01

    A 12-year-old boy presented for dental care 35 days after he fell from his bicycle. Clinical and radiographic examinations revealed a longitudinal crown-root fracture with pulp exposure in the maxillary left central incisor. The radiograph also suggested necrosis of the maxillary right central incisor. Urgent treatment of the left central incisor involved gingivectomy followed by autogenous bonding of the tooth fragment with self-curing composite resin. Immediately after bonding, coronal access was prepared, chemical and mechanical preparation was completed, and a calcium hydroxide intracanal dressing was placed. One week after the initial appointment, endodontic treatment was initiated in the right central incisor. The root canal of the maxillary left central incisor was maintained with calcium hydroxide paste (replaced at 45-day intervals) for 1 year and then definitively obturated. At the 16-year follow-up, satisfactory periodontal, esthetic, and clinical conditions were observed, and a radiograph revealed no resorption or periapical changes.

  13. 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...

  14. Spectrophotometric analysis of crown discoloration induced by MTA- and ZnOE-based sealers

    Directory of Open Access Journals (Sweden)

    Konstantinos Ioannidis

    2013-04-01

    Full Text Available Crown discoloration can be induced by root canal sealer remnants following root canal treatment. Objective: The aim of this study was to evaluate chromatic alterations in human tooth crowns induced by a Mineral Trioxide Aggregate-based sealer (MTA Fillapex® and a commonly used ZnOE-based sealer (Roth-811. The tested null hypothesis was that the application of the materials did not induce clinically perceptible crown discoloration (Ho: CIE color difference ΔE<3.7. Material and Methods: Forty five fully developed, intact, mandibular third molars were sectioned 1 mm below the cemento-enamel junction. The pulp chambers were chemomechanically debrided via the cervical access. The specimens were randomly assigned into three groups Group 1: MTA Fillapex, Group 2: Roth 811, Group 3: Negative control (unfilled and immersed in individually marked vials containing distilled water up to the cervix (37±1°C. The spectral reflectance lines were recorded by utilizing a UV-VIS spectrophotometer equipped with integration sphere in the visual spectrum at baseline, 1 week, 1 and 3 months after material placement. Data were transformed into values of the CIE L*a*b* color system and the corresponding ΔE values were calculated. Statistical analysis was performed using two-way mixed ANOVA models, at p=0.05 level of significance. Results: A statistically significant increase in a* and b* chromatic parameters of the MTA Fillapex Group was measured. However, ΔE values did not exceed the human eye perceptibility threshold (set at ΔE<3.7 during the experimental period (ΔEt3=2.88. In Roth-811 Group, a statistically significant decrease in L* and a statistically significant increase in a* and b* chromatic parameters was measured, during all observation periods. Resultant ΔE values exceeded the human eye perceptibility threshold after 1 week (ΔEt1=5.65. Conclusions: Application of MTA Fillapex in tooth crowns resulted in minimal color alterations, while Roth 811

  15. 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.

  16. Unusual extraction behaviour of crown ether when intercalated in bentonite

    Energy Technology Data Exchange (ETDEWEB)

    Sivaiah, M.V.; Krishna, R.M.; Murthy, G.S. [Andhra Univ., Nuclear Chemistry Section, Waltair (India); Venkatesan, K.A. [Indira Gandhi Centre for Atomic Research, Fuel Chemistry Div., Kapakkam (India); Sasidhar, P. [Atomic Energy Regulatory Board, Safety Research Institute, Kalpakkam (India)

    2005-04-01

    Di-cyclo-hexano-18-crown-6 (DCH18C6) has been intercalated in bentonite and the product, Ben-Crown, characterized by micro-elemental analysis, TG-DTA analysis, X-ray diffraction and IR spectroscopy. The permanent negative charge present in the bentonite layer has been exploited for more efficient extraction of cesium and strontium by Ben-Crown at nitric acid concentrations ({<=} 1.0 M) that gave only a meagre extraction when either DCH18C6 or bentonite alone were employed. The extraction of cesium and strontium has been investigated as a function of time, temperature, and the concentrations of nitric acid, metal ion and sodium nitrate. An unusual extraction phenomenon was observed at low concentrations of nitric acid ({<=} 1.0 M) in the absence of any organo-philic agents. Rapid extraction of the metal ion was followed by the establishment of an equilibrium, which occurred after 150 min. Distribution coefficients (K{sub d}) of 599 and 1007 ml g{sup -1} were obtained, respectively, for the extraction of cesium and strontium from 0.1 M nitric acid by Ben-Crown; K{sub d} decreased with an increase in the temperature or in the concentrations of nitric acid and sodium nitrate. The extraction data were fitted by the Langmuir adsorption model and the apparent experimental exchange capacity obtained by linear regression analysis was in good agreement with the amount of crown ether (0.22 mmol g{sup -1}) intercalated in bentonite. The enthalpy change ({delta}H{sup 0}) for the extraction of cesium and strontium was found to be exothermic. (authors)

  17. Telomere length and depression

    DEFF Research Database (Denmark)

    Wium-Andersen, Marie Kim; Ørsted, David Dynnes; Rode, Line

    2016-01-01

    BACKGROUND: Depression has been cross-sectionally associated with short telomeres as a measure of biological age. However, the direction and nature of the association is currently unclear. AIMS: We examined whether short telomere length is associated with depression cross-sectionally as well...... as prospectively and genetically. METHOD: Telomere length and three polymorphisms, TERT, TERC and OBFC1, were measured in 67 306 individuals aged 20-100 years from the Danish general population and associated with register-based attendance at hospital for depression and purchase of antidepressant medication....... RESULTS: Attendance at hospital for depression was associated with short telomere length cross-sectionally, but not prospectively. Further, purchase of antidepressant medication was not associated with short telomere length cross-sectionally or prospectively. Mean follow-up was 7.6 years (range 0...

  18. 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.

  19. 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.

  20. Observations on oesophageal length.

    Science.gov (United States)

    Kalloor, G J; Deshpande, A H; Collis, J L

    1976-01-01

    The subject of oesophageal length is discussed. The great variations in the length of the oesophagus in individual patients is noted, and the practical use of its recognition in oesophageal surgery is stressed. An apprasial of the various methods available for this measurement is made; this includes the use of external chest measurement, endoscopic measurement, and the measurement of the level of the electrical mucosal potential change. Correlative studies of these various methods are made, and these show a very high degree of significance. These studies involved simultaneous measurement of external and internal oesophageal length in 26 patients without a hiatal hernia or gastro-oesophageal length in 26 patients without a hiatal hernia or gastro-oesophageal reflux symptoms, 42 patients with sliding type hiatal hernia, and 17 patients with a peptic stricture in association with hiatal hernia. The method of measuring oesophageal length by the use of the external chest measurement, that is, the distance between the lower incisor teeth and the xiphisternum, measured with the neck fully extended and the patient lying supine, is described in detail, its practical application in oesophageal surgery is illustrated, and its validity tested by internal measurements. The findings of this study demonstrate that the external chest measurement provides a mean of assessing the true static length of the oesophagus, corrected for the size of the individual. Images PMID:941114

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. A Randomized Controlled Trial of Crown Therapy in Young Individuals with Amelogenesis Imperfecta.

    Science.gov (United States)

    Pousette Lundgren, G; Morling Vestlund, G I; Trulsson, M; Dahllöf, G

    2015-08-01

    Amelogenesis imperfecta (AI) is a rare, genetically determined defect in enamel mineralization. Existing treatment recommendations suggest resin-composite restorations until adulthood, although such restorations have a limited longevity. New crown materials allow for minimal preparation techniques. The aim of this study was to compare the quality and longevity of 2 crown types-Procera and IPS e.max Press-in adolescents and young adults with AI. A secondary aim was to document adverse events. We included 27 patients (11 to 22 y of age) with AI in need of crown therapy in a randomized controlled trial using a split-mouth technique. After placing 119 Procera crowns and 108 IPS e.max Press crowns following randomization, we recorded longevity, quality, adverse events, and tooth sensitivity. After 2 y, 97% of the crowns in both crown groups had excellent or acceptable quality. We found no significant differences in quality between Procera and IPS e.max Press crowns. Tooth sensitivity was significantly reduced after crown therapy (P < 0.001). Endodontic complications occurred in 3% of crowns. The results show that it is possible to perform crown therapy with excellent results and without severe complications in young patients with AI. The study is registered at http://www.controlled-trials.com (ISRCTN70438627).

  6. 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

  7. Porcelain crown with light-cured composite resin to repair all the clinical effect of anterior teeth defect%全瓷冠与光固化复合树脂修复前牙缺损的临床效果

    Institute of Scientific and Technical Information of China (English)

    姜守贵

    2016-01-01

    目的:探讨全瓷冠与光固化复合树脂修复前牙缺损的临床效果。方法选取我科2012年3月至2014年12月25例上前牙缺损的患者,对其36颗缺损的上前牙,按病例及年龄分类分为2组,全瓷冠修复组18颗患牙采用氧化锆全瓷冠修复,复合树脂修复组18颗患牙用卡瑞斯玛复合树脂充填修复。修复完成后检查修复体边缘密合性,外观及颜色,随访1年后复查,评价修复体的满意率。结果刚完成全瓷冠修复组的满意率94%,复合树脂组89%,差异无统计学意义(P>0.05)。1年后全瓷冠修复组的满意率89%,复合树脂组61%,差异有统计学意义(P 0.05). 1 years later the whole porcelain crown repair group, the satisfaction rate of 89%, the composite resin group 61%, the difference was statistically significant (P< 0.01).Conclusion the whole porcelain crown repair anterior tooth defect is a kind of ideal repair method.

  8. FEM evaluation of cemented-retained versus screw-retained dental implant single-tooth crown prosthesis

    Science.gov (United States)

    Cicciu, Marco; Bramanti, Ennio; Matacena, Giada; Guglielmino, Eugenio; Risitano, Giacomo

    2014-01-01

    Prosthetic rehabilitation of partial or total edentulous patients is today a challenge for clinicians and dental practitioners. The application of dental implants in order to recover areas of missing teeth is going to be a predictable technique, however some important points about the implant angulation, the stress distribution over the bone tissue and prosthetic components should be well investigated for having final long term clinical results. Two different system of the prosthesis fixation are commonly used. The screw retained crown and the cemented retained one. All of the two restoration techniques give to the clinicians several advantages and some disadvantages. Aim of this work is to evaluate all the mechanical features of each system, through engineering systems of investigations like FEM and Von Mises analyses. The FEM is today a useful tool for the prediction of stress effect upon material and biomaterial under load or strengths. Specifically three different area has been evaluated through this study: the dental crown with the bone interface; the passant screw connection area; the occlusal surface of the two different type of crown. The elastic features of the materials used in the study have been taken from recent literature data. Results revealed an adequate response for both type of prostheses, although cemented retained one showed better results over the occlusal area. PMID:24955150

  9. FEM evaluation of cemented-retained versus screw-retained dental implant single-tooth crown prosthesis.

    Science.gov (United States)

    Cicciu, Marco; Bramanti, Ennio; Matacena, Giada; Guglielmino, Eugenio; Risitano, Giacomo

    2014-01-01

    Prosthetic rehabilitation of partial or total edentulous patients is today a challenge for clinicians and dental practitioners. The application of dental implants in order to recover areas of missing teeth is going to be a predictable technique, however some important points about the implant angulation, the stress distribution over the bone tissue and prosthetic components should be well investigated for having final long term clinical results. Two different system of the prosthesis fixation are commonly used. The screw retained crown and the cemented retained one. All of the two restoration techniques give to the clinicians several advantages and some disadvantages. Aim of this work is to evaluate all the mechanical features of each system, through engineering systems of investigations like FEM and Von Mises analyses. The FEM is today a useful tool for the prediction of stress effect upon material and biomaterial under load or strengths. Specifically three different area has been evaluated through this study: the dental crown with the bone interface; the passant screw connection area; the occlusal surface of the two different type of crown. The elastic features of the materials used in the study have been taken from recent literature data. Results revealed an adequate response for both type of prostheses, although cemented retained one showed better results over the occlusal area.

  10. Aesthetic repair of adult upper anterior teeth by metal-porcelain crown%成人上前牙烤瓷的美容修复

    Institute of Scientific and Technical Information of China (English)

    杨巨莉; 王雁冰; 白艳杰

    2011-01-01

    目的 探讨采用烤瓷熔附金属全冠修复上前牙错(牙合)的方法及美容效果.方法 采用烤瓷熔附金属全冠、桩核冠或桥体,对78例(164颗)上前牙错(牙合)畸形患者在短时间内完成修复治疗.用制作的烤瓷牙冠修复前牙,调整颜色、形态,使其与邻近的前牙排齐,达到美容效果.结果 所有患者获随访1~6年,其中2例(2颗)出现崩瓷,1例(1颗)为桩核冠脱落,1例(2颗)为单冠脱落,2例(2颗)根折;72例患者的前牙烤瓷冠无崩瓷、松动及脱落,其颜色自然,形态美观,功能正常.结论 采用烤瓷熔附金属全冠修复成人上前牙错(牙合)治疗的方法,具有修复时间短,形态逼真,改善美观,恢复咀嚼功能的良好效果,适合在基层医院推广应用.%Objective To explore the method and aesthetic outcome of the metal-porcelain crown for the repair of adult upper anterior teeth. Methods Totally 78 patients ( 164 teeth ) with malocclusion were treated by porcelain fused to metal crown, core crown and pontic which cost a short time. After the porcelain crowns placed, their color and profile of the repaired upper anterior teeth were adjusted according to the adjacent ones to reach the aesthetic outcome. Results After 1 to 6 years follow-up, 72 cases got satisfactory results with nature color. nice contour and normal function without crown craze or loosen, except for 2 cases ( 2 teeth ) with crowns crack. 1 case ( 1 tooth ) with porcelain-fused prosthesis fallen off, 1 case ( 2 teeth ) with single crown fallen off and 2 cases ( 2 teeth ) with root fracture. Conclusion It is an easy and effective method of metalporcelain crown for the repair of adult upper anterior teeth of malocclusion with such advantages as short operating time, nice postoperative contour and normal masticatory function. It worth spreading in clinic.

  11. 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.

  12. 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

  13. 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.

  14. 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.

  15. 二氧化锆全瓷冠对牙龈健康的影响%Effect of zirconia all-ceramic crowns on gingival health

    Institute of Scientific and Technical Information of China (English)

    张非煜; 吕亚林; 董坚; 李俨; 张伟; 李国庆

    2013-01-01

    Objective To compare the effect of anterior teeth clinical restoration with zirconia all-ceramic crowns and cast all-ceramic crowns.Methods All 49 patients with 73 crowns were enrolled in zirconia group.Those anterior teeth were restored with zirconia all-ceramic crowns.The control group were selected with 32 crowns from 25 patients with cast all-ceramic crowns.One day,3 months,6 months,1 year after restoration were the time points.Marginal integrity was observed according to the standards specified by the Califcrnia Dental Association.Results All 73 zirconia ceramic crowns repairs were completed on day 1 and 3 months,6 months after restoration in zirconia group.72 anterior teeth got grade Ⅰ,1 anterior tooth got grade Ⅱ ; 1 year after the repair,70 anterior teeth got grade Ⅰ and 3 anterior teeth got grade Ⅱ.All 32 casting all-ceramic crowns restorations were completed in one day,3 months,6 months,1 year after the restoration.31 anterior teeth got grade Ⅰ,1 anterior teeth got grade Ⅱ.The clinical effects of the two types of all-ceramic crown showed no statistical difference.Conclusion Zirconia all ceramic crown has the similar gingival effect as the cast all-ceramic crowns and both of those kinds of restorations are ideal for anterior teeth repair.%目的 分析前牙美容修复中二氧化锆全瓷冠对牙龈健康的影响.方法 49例患者共73颗前牙采用二氧化锆全瓷冠修复,设为二氧化锆组;对照组选择25例患者共32颗前牙采用铸造全瓷冠修复.分别在修复后1d和3、6、12个月参照美国加利福尼亚州牙科协会制定的标准,观察牙龈健康状况.结果 二氧化锆组在修复完成第1天及第3、6个月时,牙龈健康分级Ⅰ、Ⅱ级均分别为72、1颗;修复后12个月,Ⅰ、Ⅱ级分别为70、3颗.对照组在修复完成第1天及第3、6、12个月时,牙龈健康分级Ⅰ、Ⅱ级均分别为72、1颗.2种全瓷冠的临床效果差异无统计学意义(P>0.05).结论 二氧化

  16. 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.

  17. Bonded composite resin crowns for primary incisors: technique update.

    Science.gov (United States)

    Croll, T P

    1990-02-01

    A technique for restoration of carious primary maxillary incisors with a hybrid visible light-curing composite resin and a dentinal bonding agent is described. Careful use of this technique and the new materials can provide a restoration that is esthetic and resistant to fracture and displacement. The technique requires careful preparation of the operative field and precise handling of the restorative materials. The method is illustrated by the placement of bonded composite resin crowns in a 3-year-old boy.

  18. How resilient are southwestern ponderosa pine forests after crown fires?

    OpenAIRE

    Savage, Van M.; Mast, J N

    2005-01-01

    The exclusion of low-severity surface fire from ponderosa pine (Pinus ponderosa P. & C. Lawson) forests of the Southwest has changed ecosystem structure and function such that severe crown fires are increasingly causing extensive stand mortality. This altered fire regime has resulted from the intersection of natural drought cycles with human activities that have suppressed natural fires for over a century. What is the trajectory of forest recovery after such fires? This study explores the reg...

  19. 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.

  20. 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.

  1. Curative effect analysis of front teeth full crown restoration%前牙全冠修复的疗效分析

    Institute of Scientific and Technical Information of China (English)

    贺燕; 李扬

    2014-01-01

    ObjectiveAnalysis of different metal porcelain crowns and casting porcelain crown in the repair of anterior tooth clinical results.MethodsSelect our hospital from January 2013 to January 2014 line need full crown restoration to 400 teeth of 140 patients, combining the actual requirement of patients respectively production casting four metal porcelain crowns (respectively, gold-plated nickel chromium alloy cobalt chromium alloy, palladium silver alloy, nickel chromium alloy and gold platinum alloy) and casting porcelain crown all the 80 cases, all patients were given clinical follow-up of 2 years. Evaluate each full crown restoration color, edge, surface integrity, gums healthy gums and dyeing conditions.ResultsCasting porcelain crown color effect is signifi cantly better than the metal porcelain crowns, which compare the difference was statistically signifi cant (P<0.05); In terms of marginal fi t, gold platinum alloy was signifi cantly better than several other metal porcelain crowns, compare the difference was statistically signifi cant (P<0.05); On edge coloring, color and gum health, casting porcelain crown, cobalt chromium alloy PFM crown, precious metal alloy PFM crown was signifi cantly better than nickel-chromium alloy PFM crowns, compare the difference was statistically signifi cant (P<0.05).ConclusionIn terms of marginal fi t, gold platinum alloy porcelain crowns the best clinical effect; In terms of aesthetic effect, casting porcelain crown clinical effect is best; In terms of edge coloring and periodontal health, precious metal alloy porcelain teeth and the clinical effect of casting porcelain crown is better.%目的:分析不同金属烤瓷冠和铸瓷冠在前牙修复中的效果。方法选择我院2013年1月~2015年1月收治的需要行全冠修复的140例患者上前牙400颗,结合患者的实际需要分别铸造4种金属烤瓷冠(即为镀金镍铬合金钴铬合金、钯银合金、镍铬合金和金铂合金)和铸瓷冠各80

  2. 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.

  3. 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.

  4. 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

  5. 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.

  6. 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.

  7. 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.

  8. Assessment of nickel release from stainless steel crowns.

    Directory of Open Access Journals (Sweden)

    Nahid Ramazani

    2014-06-01

    Full Text Available Adverse effects of dental materials, especially metals, have been an important issue in recent decades.The purpose of this study was to determine the amount of nickel released from stainless steel crowns in artificial saliva.In this in-vitro study, 270 stainless steel crowns were divided into five groups, each with nine subgroups. Each group (I to V was comprised of four, five, six, seven and eight crowns, respectively. Each subgroup was placed in a polyethylene jar containing artificial saliva and held in an incubator at 37°C for four weeks. The amount of released nickel was determined on days 1, 7, 14, 21 and 28, using an atomic absorption spectrophotometer. Wilcoxon Signed-Rank and Kruskal-Wallis with Dunn's post hoc tests (SPSS software, v. 18 were used for statistical analysis at a significance level of 0.05.The mean level of nickel on day 1 was more than that of day 7; this difference was statistically significant for all groups (P < 0.05, except for group II (P = 0.086. Also, the mean difference of released nickel between the groups was significant on day 1 (P = 0.006 and was insignificant on day 7 (P = 0.620. The nickel levels were zero on days 14, 21, and 28.The amount of nickel was below the toxic level and did not exceed the dietary intake.

  9. 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.

  10. 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.

  11. Effect of GLUMA desensitizer on the retention of full metal crowns cemented with Rely X U200 self-adhesive cement

    Science.gov (United States)

    Lawaf, Shirin; Jalalian, Ezatallah; Roshan, Roshanak

    2016-01-01

    PURPOSE Considering the importance of retention in the success and long-term clinical service of fixed partial dentures (FPDs) as well as the existing controversy regarding the effect of GLUMA desensitizer on the retention of full metal crowns cemented with RelyX U200 self-adhesive cement, this study aimed to assess the effect of GLUMA desensitizer on the retention of full metal crowns cemented using RelyX U200. MATERIALS AND METHODS In this experimental study, 20 sound human premolars were prepared; a 0.5 mm chamfer finish line was prepared above the cementoenamel junction. The teeth were randomly assigned to two groups: a desensitizer group (n = 10, treated with GLUMA desensitizer) and a control (n = 10, no surface treatment). Full metal crowns were fabricated of base metal alloy and had a ring. All crowns were cemented with RelyX U200 and subjected to retention test by using a universal testing machine. The data were analyzed using SPSS version 20 and independent t-test. RESULTS The mean tensile bond strength was significantly higher in the GLUMA desensitizer group (230.63 ± 63.8 N) compared to the control group (164.45 ± 39.3 N) (P≤.012). CONCLUSION GLUMA desensitizer increases the tensile bond strength of RelyX U200 self-adhesive cement to dentin. PMID:27826391

  12. 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.

  13. Changes of Dental Porcelain Fused to Metal Crown, Zirconia all Ceramic Crowns on the Periodontal Tissue%试论前牙金属烤瓷冠、氧化锆全瓷冠修复后牙周组织变化

    Institute of Scientific and Technical Information of China (English)

    谷克晓; 李宁; 刘党利

    2016-01-01

    Objective Changes of dental porcelain fused to metal crown, zirconia all ceramic crowns on the periodontal tissue of the former.Methods selected in our hospital in June 2014 to 2015 December for patients with anterior teeth with PFM crowns 100 cases as the research object,divided into observation and control group. Patients in the control group were treated by the cobalt chromium alloy porcelain crowns, the observation group with zirconia all ceramic crowns, comparative analysis of the clinical therapeutic effect of the two groups.Results observation group of gingival papilla color change, gingival grey line and black line occurred rate of gingivitis was signiifcantly lower than that of the control group. Conclusion zirconia all ceramic crown restoration has a strong aesthetic,can be used to repair the anterior teeth.%目的:研究前牙金属烤瓷冠、氧化锆全瓷冠修复后牙周组织的变化。方法选取我院2014年6月~2015年12月收治的进行前牙烤瓷冠修复患者100例为研究对象,将其分为观察与对照两组,对照组进行钴铬合金烤瓷冠修复,观察组采用氧化锆全瓷冠修复,对比分析两组临床治疗效果。结果观察组的龈乳头颜色改变、牙龈缘灰线、黑线发生率牙龈炎发生率显著低于对照组。结论氧化锆全瓷冠修复具有较强的美观性,临床上可以将其用来修复前牙。

  14. Relativistic length agony continued

    Directory of Open Access Journals (Sweden)

    Redžić D.V.

    2014-01-01

    Full Text Available We made an attempt to remedy recent confusing treatments of some basic relativistic concepts and results. Following the argument presented in an earlier paper (Redžić 2008b, we discussed the misconceptions that are recurrent points in the literature devoted to teaching relativity such as: there is no change in the object in Special Relativity, illusory character of relativistic length contraction, stresses and strains induced by Lorentz contraction, and related issues. We gave several examples of the traps of everyday language that lurk in Special Relativity. To remove a possible conceptual and terminological muddle, we made a distinction between the relativistic length reduction and relativistic FitzGerald-Lorentz contraction, corresponding to a passive and an active aspect of length contraction, respectively; we pointed out that both aspects have fundamental dynamical contents. As an illustration of our considerations, we discussed briefly the Dewan-Beran-Bell spaceship paradox and the ‘pole in a barn’ paradox. [Projekat Ministarstva nauke Republike Srbije, br. 171028

  15. 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.

  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. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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...

  2. Ground Wood Fiber Length Distributions

    OpenAIRE

    Lauri Ilmari Salminen; Sari Liukkonen; Alava, Mikko J.

    2014-01-01

    This study considers ground wood fiber length distributions arising from pilot grindings. The empirical fiber length distributions appear to be independent of wood fiber length as well as feeding velocity. In terms of mathematics the fiber fragment distributions of ground wood pulp combine an exponential distribution for high-length fragments and a power-law distribution for smaller lengths. This implies that the fiber length distribution is influenced by the stone surface. A fragmentation-ba...

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. Variation in needle nutrient concentrations in the crown of Scots pine on peatland.

    OpenAIRE

    Finér, Leena

    1994-01-01

    Variation in needle nutrient concentrations with age and vertical location in the crown was studied in three Scots pine stands growing on peat soils in eastern Finland. The concentrations of N, P, Fe and Zn decreased down the crown and those of Ca and Mn increased. Potassium and magnesium concentration patterns differed between sites. Potassium and Mg concentrations were highest in the current needles at all heights in the crown, which was presumably due to retranslocation from the older nee...

  8. Strategic Marketing Plan For Wedding Store : Case: Golden Crown Wedding Store, China

    OpenAIRE

    Wu, Fan

    2013-01-01

    ABSTRACT Wu, Fan 2012. Strategic Marketing Plan for Golden Crown Wedding Store. Case: Golden Crown Wedding Store, China. Bachelor’s Thesis. Kemi-Tornio University of Applied Sciences. Business and Culture. Pages 39. Appendices 1- 2. The objective of this thesis is to build a strategic marketing plan for the Golden Crown Wedding Store. The strategic marketing plan and the analysis of the situation of the market are the main part of the thesis. This thesis will help the case company to ...

  9. 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.

  10. A Market-Window Analysis for Crown-Cut Broccoli Produced in Southwest Virginia

    OpenAIRE

    Dillard, John; Kmak, Heather; Russ, M.J.; Coale, Charles W., Jr.; Bratsch, Tony; Reaves, Dixie Watts

    2006-01-01

    This research determines the profitability for farmers of marketing film-wrapped Crown-Cut broccoli in Southwest Virginia. Historical price data was collected in three eastern terminal markets (Atlanta, Baltimore, and Philadelphia) for Crown-Cut and bunched broccoli from October 1998 to January 2005. Cost-of-production budgets were estimated for Crown-Cut broccoli. The economic data was entered into a market window analysis and the profitability of each market was evaluated. The profitability...

  11. Fracture Strength of Aged Monolithic and Bilayer Zirconia-Based Crowns

    OpenAIRE

    Deborah Pacheco Lameira; Silva, Wilkens Aurélio Buarque e; Silva, Frederico Andrade e; De Souza, Grace M.

    2015-01-01

    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 mo...

  12. Wear Behavior of Ceramic CAD/CAM Crowns and Natural Antagonists

    Directory of Open Access Journals (Sweden)

    Ella A. Naumova

    2017-02-01

    Full Text Available Objective: Evaluation of wear behavior of computer-aided design/computer-aided manufacturing (CAD/CAM crowns from various restorative materials and natural antagonists. Method: Full CAD/CAM crowns fabricated with nanoceramic resin (Lava Ultimate (LU, a glass ceramic in a resin interpenetrating matrix (Vita Enamic (VE and a lithium silicate reinforced ceramic enriched with zirconia (Vita Suprinity (VS were cemented on human molars. The crown and antagonists were subjected to simulated chewing. 3D data sets, before and after the chewing simulation, were generated and matched. Occlusal surface roughness, vertical and volume loss of the crowns and antagonists were analyzed. Results: Crown roughness was significantly different between the LU and VE groups after chewing simulation. Crown vertical loss differed in all groups. The highest crown volume loss was found in the LU group, and the lowest in the VE group. Comparisons between the LU and VE groups and the LU and VS groups were significantly different. The highest antagonist volume loss was reached in the VE group, the lowest was in the LU group. Conclusion: Roughness increased after chewing simulation. LU crowns are the most natural antagonist-friendly; these were the most susceptible to vertical and volume loss. Of the tested materials, the VE crowns are the most stable regarding occlusion.

  13. 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.

  14. 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