Applicability of Bolton's tooth size ratios to a Japanese orthodontic population

Previous studies have shown that tooth size ratios are ethnicity-, race-, and sex-specific. This study was carried out to determine anterior and overall ratios in a Japanese population and to compare them with Bolton's ratios. Numerical data were obtained from 60 pairs of dental casts of 30 male and 30 female Japanese orthodontic patients. The mesiodistal widths from first molar to first molar were measured on each cast to the nearest 0.01 mm, by using digital calipers, and the anterior and overall ratios were calculated. The Kolmogorov-Smirnov test, the parametric t test, and Student t test were used for statistical analyses. No statistically significant difference between men and women was found in either the anterior or overall ratio. The combined male and female anterior and overall ratios were 78.39 ± 2.18% and 91.60 ± 2.11%, respectively. The combined male and female anterior ratio showed a statistically significant difference from the Bolton standard, whereas the overall ratio showed no statistically significant difference. Significant discrepancies in the anterior and overall ratios were found in 21.6% and 8.3% of patients, respectively. A high prevalence rate of an anterior tooth size discrepancy more than 2SD above Bolton's mean was found. Bolton's anterior ratio was not applicable to the Japanese population, and specific standard tooth size ratios for the Japanese population are needed.     

不同方法治疗牙齿敏感症的疗效分析

目的 :比较激光 ,激光加氟化钙和涂擦Gluma等 3种方法治疗牙齿敏感症的效果。方法 :按就诊顺序 ,随机选择 3组病例 ,分别采用激光、激光加氟化钙、涂擦Gluma进行牙齿敏感症的脱敏治疗。结果 :三种脱敏方法的即刻疗效比较无显著性差异 ,P >0 .0 5 ;一月后 ,Gluma组疗效低于另外两种方法组 ,有显著性差异 ,P <0 .0 5 ;随着观察期的延长 ,三种治疗方法的有效率逐渐降低 ,半年后 ,激光加氟化钙组的有效率为 67.9% ,激光组为 49.4% ,Gluma组为 2 3 .3 % ,差异有显著性 ,P <0 .0 1。结论 :三种方法治疗牙齿敏感症均有较好的即刻效果 ,远期疗效以激光组和激光加氟化钙组为优 ,激光氟化钙组半年后疗效仍为 67.9% ,显示了较好的应用前景。     

Evaluation of self-reported measures for prediction of periodontitis in a sample of Brazilians

Background: Questionnaires including self‐reported measures have become effective as a means of accessing many diseases. The aim of the present study is to evaluate the performance of a set of self‐reported periodontal measures on estimating the prevalence of periodontitis. Methods: The sample comprised 284 individuals, aged 18 to 60 years, from Belo Horizonte, Brazil. Full‐mouth periodontal examinations were performed and periodontal parameters were recorded. Periodontitis was categorized as no or mild, moderate, and severe. Each participant answered 18 questions covering sociodemographic variables, known risk factors, and self‐reported periodontal measures. Questions were globally tested through logistic regression analysis. Results: The complete final model for moderate periodontitis included age, dental flossing, and gum disease (sensitivity = 23.1%; specificity = 98%; area under the receiver operating characteristic curve = 75.4%). The complete final model for severe periodontitis included all previously cited variables in addition to the number of teeth (sensitivity = 36.4%; specificity = 96.9%; area under the receiver operating characteristic curve = 85.3%). Conclusions: Self‐reported periodontal measures showed a moderate predictive value for periodontitis prevalence. The use of these measures could be a good strategy in investigating prevalence of periodontal disease.     

三种桩核冠修复老年人上前牙残根残冠临床效果的比较

目的:比较贵金属桩核+贵金属烤瓷冠、全瓷桩+全瓷冠、纤维桩+全瓷冠修复老年人前牙残根残冠的临床效果.方法:随机选择60--75岁上前牙残根残冠患者39例,其中贵金属桩核+贵金属烤瓷冠、全瓷桩+全瓷冠、纤维桩+全瓷冠各13例.使用Shade-eye电脑比色仪测定、比较三组的Shade值,于治疗完成后3个月,6个月,12个...     

Effectiveness of three age estimation methods based on dental and skeletal development in a sample of young Brazilians

ObjectiveThis study compared three methods designed for age estimation.MethodsA sample of 468 radiographs (234 panoramic and 234 carpal radiographs) collected from patients ranging from 5 to 14 years old (mean age: 11.27 years old ± 2.27 years) was used. Three age estimation methods: were applied: one founded on dental development, one founded on hand and wrist development, and a method combining both measurements. For each method, the mean error (ME), mean absolute error (MAE), root mean square error (RMSE), and mean percentage of absolute error (MPAE) were quantified. The methods: were compared based on their effectiveness for estimating age in relation to sex and age range.ResultsThe data show that the method exclusively using the development of the hand and wrist had the highest error rates (ME: 1.28 M, 1.85F; MAE: 1.64 M, 1.96F; RMSE: 1.94 M, 2.32F) for both males (M) and females (F). In males, the method combining dental and skeletal development obtained outcomes that were slightly better than the method founded on only dental development (MPAE: 6.99% and 7.47%, respectively). In females, the opposite result was observed (MPAE: 8.48% and 6.59%, respectively). The method founded exclusively on skeletal development significantly overestimated (p = 0.001) the age (mean chronological and estimated ages: 11.27 and 12.88, respectively).ConclusionThe methods involving dental development provided more accurate age estimates of chronological age. The method exclusively based on hand and wrist development resulted in outcomes that were highly discrepant from the chronological age.     

Comparison of three anthropometric techniques for tooth selection

The absence of a reliable method to assess the proper dimension of artificial teeth can lead to errors that reduce aesthetic outcomes of the dental treatment. Previous studies indicate facial anthropometric parameters as guides to estimate the width of the six maxillary anterior teeth. Nasal width, distance between the medialis angles of the eyes and mouth width were measured in young subjects Brazilian as well as the width of their six maxillary anterior teeth. Data were analyzed by ANOVA/Tukey's (p < or = 0.05). The distance between the medialis angles of the eyes is a reliable anthropometric method to indicate the width of artificial teeth similar to the natural extracted.     

Deciduous tooth size standards for American blacks.

Normative standards for tooth sizes are valuable for assessing a given patient's status, both clinically and for evaluating intrinsic (e.g., genetic, chromosomal aberrations) and acquired conditions. There are, however, very few published standards for American Blacks and none for the deciduous teeth. Mesiodistal and buccolingual crown diameters are reported here for a series of 100 Black children. As with the permanent dentition, the primary teeth of Blacks are appreciably larger than Whites, though the amount differs by tooth type. In general, while all teeth are larger than norms for Whites, the posterior teeth (m1, m2) are preferentially larger. Applications of these standards are discussed.     

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牙拔除术是口腔颌面外科最常用、最基本的手术,不良的操作方法会造成软、硬组织的创伤,并影响拔牙创的愈合及今后义齿的修复,标准化和规范化的拔牙方法不但可减少拔牙时间和创伤,而且可降低拔牙风险和并发症的发生。     

A model for the prediction of tooth wear in individuals

BACKGROUND: Easily applied, age-specific standards are useful in assisting clinicians to decide whether the extent of tooth wear observed in a given patient at a specific age is acceptable or whether intervention is indicated. METHOD: A simple method of scoring tooth wear and previously established mathematical relationships between tooth wear scores and age, provide the basis of a method for predicting tooth wear scores. In its most specific form, the method can be used to predict tooth wear scores for individual patients at subsequent ages. Alternatively, tables or graphs can be consulted to provide a less precise prediction of tooth wear that can assist clinicians to decide whether the amount of wear reflects high, moderate or low rates of wear at the specified age. CONCLUSION: In cases where there is no reason to believe that aetiological factors have changed significantly over time, data obtained from the methods described can assist clinicians to plan appropriate management for patients presenting with unacceptable levels of tooth wear.     

Comparison of three methods of profile change prediction in the adult orthodontic patient

Potential changes in the contour of the facial profile that accompany tooth movement can be important considerations in developing an orthodontic treatment plan. The objective of this study was to compare the accuracy of three different methods of predicting horizontal soft-tissue changes. Eighty-three nongrowing, orthodontically treated patients comprised the sample. Pretreatment and posttreatment lateral cephalometric hard- and soft-tissue landmark points were digitized. A coordinate system was defined, landmark coordinates were corrected for magnification, and then hard- and soft-tissue, angular, and linear measures were calculated by computer programs developed on a DEC PDP 11/44. The accuracy of prediction of soft-tissue landmark changes was compared for three prediction methods: (1) use of ratios of means of soft-tissue changes to corresponding hard-tissue changes, (2) use of a bivariate regression equation on corresponding hard-tissue landmark changes, and (3) use of stepwise multiple regression with hard-tissue changes and initial hard- and soft-tissue facial characteristics as predictor variables. For predicting changes of four soft-tissue points, multiple regression equations were slightly more accurate than ratio of means predictions. The standard errors of the estimate ranged from 0.7 to 1.1 mm for the multiple regression predictions; these were from 0.2 to 1.4 mm lower than those obtained for ratio of means predictions. The accuracy of the bivariate regression prediction technique fell between that of the other two methods. Examination of the residuals showed that the multiple regression equations consistently underpredicted the most extreme soft-tissue facial changes.     

Comparison of three methods for detection of carious lesions in proximal surfaces versus direct visual examination after tooth separation

The present study aimed to compare clinical, fiber-optic transillumination and bite-wing radiographic assessment of carious lesion depth in contacting proximal surfaces with the results obtained by direct visual inspection after tooth separation of the respective surfaces. It is suggested that when a carious lesion is diagnosed as non-cavitated by clinical examination or restricted to enamel by FOTI or radiographic examinations in a population of children with low caries prevalence, dentists should adopt a preventive approach.     

拔牙止血方法研究现况综述

拔牙后出血是术中及术后极其常见的并发症之一。随着当今三高（高血压、高血脂、高血糖）等各种慢性系统性疾病的高发以及发病人群的低龄化,拔牙后出血发病率逐年增加,且常导致患者生理及心理各种不良后果,尤其伴随“牙医恐惧症”渐被关注,减少甚至避免拔牙出血的方法很有研究价值。本文搜索了CNKI内,1990年-2017年的相关文献,拟用关键词“拔牙”“止血”“并发症”等,经筛选后62篇纳入整理归纳。根据近30年来有关中西医各类拔牙止血方法的机制、利弊及临床疗效的研究作综述,旨在为未来临床新的拔牙止血方法提供科学依据。     

Inhibition of apoptosis in early tooth development alters tooth shape and size

Apoptosis plays important roles in various stages of organogenesis. In this study, we hypothesized that apoptosis would play an important role in tooth morphogenesis. We examined the role of apoptosis in early tooth development by using a caspase inhibitor, z-VAD-fmk, concomitant with in vitro organ culture and tooth germ transplantation into the kidney capsule. Inhibition of apoptosis at the early cap stage did not disrupt the cell proliferation level when compared with controls. However, the macroscopic morphology of mice molar teeth exhibited dramatic alterations after the inhibition of apoptosis. Crown height was reduced, and mesiodistal diameter was increased in a concentration-dependent manner with z-VAD-fmk treatment. Overall, apoptosis in the enamel knot would be necessary for the proper formation of molar teeth, including appropriate shape and size.     

牙体预备形态对烤瓷贴面复合体抗折强度及断裂模式的影响

目的比较三种牙体预备方法对烤瓷贴面复合体（PVCs）抗折强度及断裂模式的影响。方法分别对离体上颌中切牙进行3种形态（I型、L型、U型）牙体预备，制作长石质烤瓷贴面，树脂黏接剂黏接．用MTS力学实验机测试各牙的断裂载荷值，记录瓷贴面的断裂频数，数据作统计学分析。结果I、L、U三型牙体预备的PVCs与天然牙对照组的断裂载荷值分别为278．61±73．86N（n=9）．295．17±71．76N（n=9），303．42±96．87N（n=8），332．29±60．06N（n=10），经统计学分析四组间断裂载荷值及瓷贴面的断裂模式差别无统计学意义（P〉0．05），3组实验组与对照组的牙体断裂模式差异有统计学意义（P〈0．05）。结论在正中[牙合]瓷贴面间接受力的条件下，采用3种牙体预备设计的PVCs均具有良好的的抗折性能．但烤瓷贴面修复改变了牙体组织在加载条件下的力学特性。     

全冠预备体评价指标的计算机辅助量化方法

目的基于三维扫描和逆向工程技术,研究全冠预备体临床评价指标的量化方法,并为专用评价软件的研发建立关键技术路线。方法在教学用标准牙列石膏模型上,对左侧上颌第一磨牙进行全瓷冠牙体预备,用牙颌模型三维激光扫描仪获取预备前牙冠、预备体代型、邻牙以及对骀牙三维点云数据,通过对预备体及预备前牙冠数据进行点云间三维差异分析,得到牙体预备量的量化分布情况。基于点云分割及特征点云提取分析的方法,在所得截面下进行全冠预备体轴壁倾斜度及肩台宽度的定量表示的研究。结果通过对点云数据进行处理分析,得到牙体预备量、预备体轴壁倾斜度及肩台宽度的量化指标。结论本研究应用逆向工程软件,初步建立一种全冠预备体关键评价指标的量化表示方法。     

小型猪发育期牙胚蛋白提取方法探讨

目的：比较不同蛋白质提取方法在牙胚蛋白提取中的效果,寻找适合牙齿发育高通量蛋白质组学分析的蛋白质提取方法。方法：取猪胚胎第40、50、60天第三乳磨牙牙胚,利用碱性碳酸盐溶液提取牙胚初步钙化部分的蛋白,通过聚丙烯酰胺凝胶电泳比较液氮研磨法和电动研磨器研磨法提取牙胚总蛋白效果,BCA（bicinchoninic acid）蛋白浓度测定法比较 RIPA 裂解液与尿素溶液提取牙胚总蛋白含量。结果：与液氮研磨法相比,电动研磨法提取蛋白后的聚丙烯酰胺电泳图谱蛋白条带明显更深,蛋白含量高。尿素溶液对牙胚总蛋白的提取量高于 RIPA 裂解液组,蛋白电泳分离效果均可。结论：采用电动研磨器研磨牙胚,组织损失量小,提取蛋白效果好于液氮研磨;采用尿素溶液提取牙胚总蛋白效果优于 RIPA 裂解液。初步找到适合下游高通量蛋白质组学分析的牙胚蛋白提取方法。