Tanaka-Johnston dentition analysis for northern Chinese

目的 分析北方汉族青少年下颌切牙总宽度与尖牙、双尖牙总宽度之间的相关性,探寻适合目标人群的Tanaka-Johnston预测方程.方法 从就诊于首都医科大学口腔医学院正畸科的病例中选取记存模型127副.研究下颌切牙总宽度与尖牙、双尖牙总宽度之间的相关性,建立北方汉族人的Tanaka-Johnston预测方程,并评价不同预测方程的准确性.结果 男性组下颌切牙总宽度与上、下颌尖牙双尖牙总宽度之间相关系数r为0.71、0.77,女性组r为0.50、0.56.除本研究得出的方程外,其他预测方程普遍存在低估倾向.男性组实测值与预测值之差小于1mm的以北方汉族人方程上颌84%、下颌88%为最高;女性组以成都汉族人方程上颌74%,下颌81%为最高.结论 与女性相比,男性下颌切牙总宽度与尖牙、双尖牙总宽度存在较强的正相关关系.预测准确度最高的方程分别为:男性上颌Y=11.8+0.5X,下颌Y=10.9+0.5X;女性上颌Y=11.1+0.5X,下颌Y=10.0+0.5X.     

替牙期未萌尖牙、前磨牙宽度和预测方程的建立

目的优化选择针对未萌尖牙、前磨牙宽度预测的基牙组合。方法取正畸科初诊患者的研究模型,按一定标准随机选出恒牙列模型180副,利用电子游标卡尺(精度0.01 mm)测量牙冠近远中径,并对测量值进行相关与回归分析。结果得到了与未萌尖牙、前磨牙宽度相关度较高的基牙组合,即,上颌第一磨牙和上、下颌中切牙联合;此组合与上、下颌预测牙的相关度分别为0.753和0.834,具有统计学意义(P≤0.001)。以此为基础进行回归分析,建立了预测上、下颌尖牙、前磨牙宽度之和的回归方程。结论建立了一组适合中国北方地区替牙期儿童未萌尖牙、前磨牙宽度的预测方程:男性Y=0.64X+6.89(上颌),Y=0.79X+2.45(下颌);女性Y=0.64X+6.86(上颌),Y=0.72X+3.90(下颌)(Y代表一侧未萌尖牙、前磨牙近远中宽度和,X代表双侧上颌第一磨牙及上、下颌中切牙的近远中宽度和的一半)。     

错畸形患者未萌尖牙、前磨牙牙冠宽度的预测

目的通过对错畸形患者的尖牙、前磨牙与其他牙(组)牙冠宽度的相关性分析,为错畸形人群的尖牙、前磨牙的牙冠宽度的预测提供科学依据。方法选择南京医科大学附属口腔医院正畸科就诊的江苏籍错畸形患者模型382副,按照安氏Ⅰ、Ⅱ1、Ⅱ2、Ⅲ类分组,测量牙冠宽度,进行尖牙、前磨牙与其他牙(组)的相关性分析,并建立预测方程。结果建立错畸形人群的尖牙、前磨牙牙冠宽度之和的预测方程:男性U3U4U5=0.270X+3.504(r2=0.5821),L3L4L5=0.272X+2.390(r2=0.5977);女性U3U4U5=0.221X+6.884(r2=0.4951),L3L4L5=0.230X+5.173(r2=0.5000)。X为上、下颌中切上、下颌第一磨牙牙冠宽度之和。结论本研究所建立的回归预测方程要优于Moyers预测法,回归预测方程不因错畸形安氏分类的不同而有差别。     

研究上前牙区角化龈宽度和牙龈组织厚度之间的关联

本研究的目的是为了评价角化龈的宽度和厚度之间是否为正相关。纳入了60位20-35岁的患者（30位男性,30位女性）,对其右上尖牙、侧切牙和中切牙的软组织进行检查。使用一个带有橡皮止动片的牙髓探针和一个分辨率为0.01mm的数字化卡尺进行数据测量。获得的数据包括角化龈的宽度和厚度。结果显示,侧切牙的平均角化龈宽度最宽（5.54±1.09mm）,中切牙次之（4.62±1.02mm）,尖牙最窄（4.32±1.33mm）。中切牙的平均牙龈厚度最厚（1.17±0.20mm）,侧切牙次之（1.04±0.24mm）,尖牙最薄（0.87±0.27mm）。男性与女性之间的角化龈宽度和厚度的差异没有统计学意义。上颌尖牙（Pearson r=0.398,P〈0.05）、侧切牙（Pearson r=0.369,P〈0.05）和中切牙（Pearson r=0.492,P〈0.05）区域的角化龈宽度和厚度之间为正相关。初步得出结论,对于20-35岁的患者,右上尖牙、侧切牙、中切牙的角化龈宽度和厚度之间为正相关。     

安氏Ⅱ^1类错He上颌尖牙远中移位后切牙及磨牙位置变化的研究

目的探讨安氏Ⅱ1类错拔牙矫治中,上下颌磨牙及切牙的位置变化。方法选择15名11－16岁拔除四个第一双尖牙的安氏Ⅱ1类错病例,用方丝弓矫治技术,口外力加强上颌磨牙支抗,治疗前及以间断力后移上颌尖牙到与第二双尖牙接触时,进行X线头影测量及统计分析。结果上颌磨牙前移了0.9mm,比下颌磨牙整体前移少约2mm;上切牙舌侧斜移动了4.1mm;下切牙舌向移动了1.8mm,比上颌磨牙前移少1mm。结论控制上颌磨牙支抗并增大弓丝的滑动,可使上颌切牙在未主动内收前舌向移动;减少下颌尖牙的后移则有利于下颌磨牙的前移。     

安氏Ⅱ~1类错上颌尖牙远中移位后切牙及磨牙位置变化的研究

目的　探讨安氏Ⅱ1类错拔牙矫治中 ,上下颌磨牙及切牙的位置变化。方法　选择 15名11— 16岁拔除四个第一双尖牙的安氏Ⅱ1类错病例 ,用方丝弓矫治技术 ,口外力加强上颌磨牙支抗 ,治疗前及以间断力后移上颌尖牙到与第二双尖牙接触时 ,进行X线头影测量及统计分析。结果　上颌磨牙前移了 0 9mm ,比下颌磨牙整体前移少约 2mm ;上切牙舌侧斜移动了 4 1mm ;下切牙舌向移动了 1 8mm ,比上颌磨牙前移少 1mm。结论　控制上颌磨牙支抗并增大弓丝的滑动 ,可使上颌切牙在未主动内收前舌向移动 ;减少下颌尖牙的后移则有利于下颌磨牙的前移     

蒙古族和汉族正常牙人群恒牙牙齿大小的比较研究

本研究旨在建立正常牙蒙古族人群牙齿大小和Bolton指数的测量标准,并比较与其他种族和国内其了民族测量值的差异.选取正常牙蒙古族人102名,正常牙汉族人76名,采用模型测量法.结果与分析男性蒙古族人群的上颌第二恒磨牙牙冠宽度明显大于汉族人的测量值,而下尖牙和下第一恒磨牙匠牙冠宽度明显大于汉族人的测量值,而下尖牙和下第一恒磨牙的牙冠宽度测量值则明显小于汉族人相应牙齿的测量均值.女性与汉族正常牙合,女性牙冠宽度测量值比较,蒙古族女性的上颌第二恒磨牙、下颌中切牙及第一恒磨牙的牙冠宽度测量值大,有显著性差别.     

西安地区正常(牙合)牙冠宽度及上、下颌牙量相关性研究

目的:测量西安地区汉族人正常(牙合)牙冠宽度,并对上下颌牙量的相关性进行研究.方法:选取符合纳入标准的个别正常(牙合)共计107例(男52例女55例),测量各个牙齿的最大近远中径宽度,然后依据测量值进行上、下颌牙量的相关性研究.结果:得出了西安地区正常(牙合)各个牙牙冠宽度,其中上颌中切牙、侧切牙、尖牙、第一恒磨牙以及下颌的尖牙、前磨牙牙冠宽度男性明显大于女性,存在着显著的统计学差异.上、下颌前牙量之间及上下颌总牙量间均存在着显著的相关性(γ前牙=0.754,γ全牙=0.851),Bolton指数的正常值分布范围为78.32±3.01,全牙比正常值分布范围为91.10±2.27;根据这种上、下颌牙量间的相关性得出了用于计算牙量不调量的直线回归方程.结论:西安地区部分牙冠宽度男大于女,上下颌牙量间存在相关性.     

双侧上颌尖牙与第二双尖牙易位1例报告

双侧上颌尖牙与第二双尖牙易位１例报告牙易位通常为相邻牙的位置发生交换。常见于上颌尖牙与第一双尖牙位置更换,也有侧切牙与尖牙发生易位者。而双侧上颌尖牙与第二双尖牙隔位易换,实属少见,报告如下。患者女性,３３岁。右上颌牙位不正,嵌食３年,要求拔牙而就诊。...     

复盖桩托牙15例体会

本组15例,男性12例,女性3例;年龄在51～81岁间,平均60岁。上颌7例,下颌8例,15例共复盖桩20枚。上颌7例中,切牙单桩1例,尖牙单桩5例,切牙、尖牙双桩1例。下颌8例中,切牙单桩2例,尖牙单桩1例,切牙双桩1例,尖牙双桩4例。15例均经2年以上观察,其中下颌单桩1例一月后因根尖周炎而拔除牙根,另1例上颌单桩二月后牙根自行脱落。     

恒尖牙双尖牙近远中径预测方程

目的：为口腔正畸临床混合牙列间隙分析提供简捷,便利的诊断依据。方法：在模型上测量牙冠近远中径,对测量值进行直线回归与相关分析。结果：下切牙与尖牙,双尖牙近远中径存在直线相关关系。结论：建立了汉族人群上,下颌尖牙双尖牙近远中径观测方程。     

Mixed dentition analysis in a Moroccan population.

The aims of this study were to produce odontometric data for a Moroccan population, to test Tanaka and Johnston and Moyers methods, to derive regression equations and elaborate a specific orthodontic prediction table for Moroccan children. 50 dental casts of Moroccan students (25 males, 25 females, mean age 22.6 years sd 1.35) were used to perform measurements of the greatest mesiodistal widths of all mandibular and maxillary canines and premolars and mandibular incisors with an orthodontic calliper. Significant sexual dimorphism was found in tooth sizes (p = .001). The study revealed close relationships between the total mesiodistal widths of the mandibular permanent incisors and that of the maxillary and mandibular canines and premolars. The correlation coefficients (r) and the coefficient of determination (R2) were better sexes combined for the maxilla (r = 0.60 ; R2 = 0.36 ) and for the mandible (r = 0.61 ; R2= 0.37). The regression equations elaborated for males and females were used as a basis for establishing an orthodontic prediction table for Moroccan children.     

Mixed dentition space analysis in a Jordanian population: comparison of two methods

AIMS: To test the reliability of the Moyers charts and the Tanaka and Johnston equations in Jordanians and to derive coefficients of correlation between the combined mesiodistal widths of the four permanent mandibular incisors and the combined widths of the canine and premolars of the maxillary and mandibular quadrants. METHODS: The dental models of the dentition of 130 male and 96 female Jordanian subjects (age range is 14-16 years) with complete permanent dentition were randomly selected. The mesiodistal width of the four permanent mandibular incisors, maxillary and mandibular canines, and premolar teeth were measured using a vernier gauge caliper to the nearest 0.1 mm. The actual teeth measurements were then compared with the predicted values derived from the Tanaka and Johnston equations and Moyers probability tables. Correlation and linear regression analyses were performed between the predicted and actual tooth size for Jordanian children and standard regression equations were developed. RESULTS: Except for the maxillary arch in male subjects, Tanaka and Johnston regression equations underestimated the mesiodistal widths of permanent canines and premolars. On the other hand, there were no statistically significant differences between actual mesiodistal widths of canines and premolars and the predicted widths from Moyers charts at the 65% and 75% level for the lower and upper arches in male subjects and at the 85% level for the upper and lower arches in female subjects. For the newly developed regression equations, the correlation coefficients between the sum of the mandibular four incisors and the sum of the canine and premolars were 0.60 (for lower) and 0.51 (for upper) in male subjects and 0.59 and 0.64, respectively, in female subjects. CONCLUSIONS: (1) Tanaka and Johnston prediction method was not accurate when applied to a Jordanian population. (2) Moyers method for prediction can be used for Jordanian children at different probability levels for male and female subjects.     

New regression equations for mixed dentition space analysis in Nepalese mongoloids

Background

Mixed dentition space analysis methods using regression equations, namely, Moyers’ analysis and Tanaka-Johnston analysis are commonly used around the world. However, the applicability of these analyses among different racial groups have been questioned. The primary objective of this study was to assess the applicability of the Moyers’ and Tanaka-Johnston analyses among Nepalese Mongoloids and to develop regression equations for the same population if needed.

Methods

One hundred (50 males and 50 females) pre-treatment study models of the Nepalese Mongoloid patients undergoing orthodontic treatment were retrieved from the archives of the department of Orthodontics. The mesiodistal widths of mandibular incisors and widths of canines and premolars of all 4 quadrants were measured by a single investigator using a digital caliper to the nearest 0.01?mm. Predicted widths of canines and premolars were obtained using standard Moyers’ and Tanaka-Johnston analyses and then compared with the measured widths.

Results

The measured widths of canines and premolars were significantly different from the predicted widths obtained from Moyers’ and Tanaka-Johnston analyses. Strong and positive correlations were found between the sum of mesiodistal widths of mandibular incisors and the sum of mesiodistal widths of canines and premolars in males (0.73 for maxillary arch and 0.68 for mandibular arch) and females (0.64 for maxillary arch and 0.79 for mandibular arch).

Conclusions

The Moyers’ and Tanaka-Johnston analyses did not accurately predict the mesiodistal width of unerupted canines and premolars for Nepalese Mongoloid population. Hence, new regression equations have been developed for this population. However, validation studies should be conducted to confirm the applicability and accuracy of these equations.

     

Mixed dentition analysis in a Senegalese population: elaboration of prediction tables.

Estimating the size of unerupted teeth is an essential aspect of orthodontic diagnosis and treatment planning in the mixed dentition. Three main methods have been used to estimate the mesiodistal crown widths of unerupted canines and premolars: direct measurements on radiographs; calculations from prediction equations and tables; and a combination of radiographic measurements and prediction tables. Because there are clear racial differences in tooth sizes, the objectives of this study were to produce odontometric data, correlation coefficients between the combined mesiodistal widths of the permanent mandibular incisors and the canine and premolars for each quadrant, and prediction tables with the regression equations, specifically for Senegalese children. Fifty black Senegalese students (25 women, 25 men, mean age 23.50 years) were selected from the University Cheikh Anta Diop in Dakar, Senegal. The mesiodistal crown diameters of the permanent teeth were measured with calipers. Significant sexual dimorphism was found in tooth sizes. The correlation coefficients between the total mesiodistal width of the mandibular permanent incisors and that of the maxillary and mandibular canines and premolars were found to be 0.53 and 0.70, respectively. The standard error of the estimate was better (0.66) for women in the maxilla, and the r(2) values ranged from 0.46 to 0.57 for both sexes. Prediction tables were prepared. The accuracy of the prediction tables should be tested in a larger sample including more ethnic groups.     

Treatment outcomes for adolescent ectodermal dysplasia patients treated with dental implants

To evaluate dental implant survival in patients with ectodermal dysplasia (ED). To assess patterns of hypodontia in this patient group. METHOD:. A retrospective analysis of the use of dental implants in ED patients treated at the Royal Children's Hospital, Melbourne. RESULTS: Sixty-one implants were placed into 14 patients (nine male and five female). The mean age of patients receiving maxillary implants was 18 years 6 months (range 17 years 9 months-20 years 0 months) and mandibular implants was 17 years 5 months (range 12 years 2 months-21 years 11 months). The mean follow-up period was 3 years 4 months (range 1 year 18 months-5 years 1 month). Forty-three implants were placed in the anterior mandible, three in the posterior mandible and the remaining 15 in the anterior maxilla. Of the 61 implants placed, 54 [88.5%] successfully integrated and were able to be restored. Three of the 15 implants placed into the anterior maxilla [20%] failed, while four of the 46 in the anterior mandible failed [8.7%]. Five of the 14 patients [35.7%] had at least one implant fail prior to abutment connection. At the 12-month review appointments, 41 of the integrated 54 implants [76%] were reviewed and classed as successful, giving an overall success at follow up of 67.2%. Thirteen implants [21.3%] were unable to be reviewed owing to geographical reasons. Teeth most likely to be present in the maxilla were the central incisors [71%], first molars [54%] and canines [43%], whereas in the mandible they were the canines [53%] and the first premolars and first molars [40%]. CONCLUSIONS: Dental implants can be placed, restored and loaded in ED patients. Maxillary teeth most likely to be present are the central incisors, canines and first molars, whereas in the mandible the canines, first premolars and molars are most likely to be present. Prior to cessation of growth, implant placement in the symphyseal region of the anterior mandible may be performed with caution. Despite the limited numbers and with due consideration to jaw development, the results support the continual use of endosseous dental implants in this group of patients for optimal clinical outcomes.     

Mixed dentition analysis in a Jordanian population

OBJECTIVE: To examine the applicability of the Tanaka and Johnston method of prediction in a Jordanian population and to develop a new prediction method for this specific population if necessary. MATERIALS AND METHODS: Three-hundred and sixty-seven Jordanians (193 female, 174 male, mean age 15.5 years) were randomly selected to represent 0.1% of 10th grade schoolchildren from Amman, Jordan. The mesiodistal crown diameters of the permanent teeth were measured and compared with the predicted values derived from the Tanaka and Johnston equations. RESULTS: Significant sexual dimorphism was found in tooth sizes. The correlation coefficients between the total mesiodistal width of the mandibular permanent incisors and that of the maxillary and mandibular canines and premolars were found to be 0.60 and 0.66, respectively. There were significant differences between the actual measurements and measurements derived from the Tanaka and Johnston equations. New linear regression equations were derived for both genders to allow tooth size prediction in Jordanians. CONCLUSIONS: There is a limitation in the application of the Tanaka and Johnston's prediction method to a Jordanian population. It is important to use separate equations for male and female patients.     

Predicting the size of unerupted canines and premolars of the maxillary and mandibular quadrants in an Iranian population

The aim of this investigation was to examine the accuracy of Moyers probability tables and the Tanaka and Johnston prediction equations in predicting the size of unerupted canines and premolars of the maxillary and mandibular quadrants in an Iranian population and to derive a standard formula for it. METHODS: Out of a sample of 280 subjects, 50 (25 males and 25 females) were selected by specific inclusion criteria. An electronic digital caliper was used to read the nearest 0.01 mm. The teeth measurements derived were compared with those predicted from Tanaka Johnston equations and Moyers probability tables and then standard regression were developed. RESULTS: Tanaka and Johnston regression equations overestimate the mesiodistal width of permanent canines and premolars. There were no statistically significant differences between actual mesiodistal width of canines and premolars and the predicted width from Moyers charts at 65% for the lower and upper arches in male subjects and for the lower arch in females but none of the probabilities has good accuracy for the upper arch in females. For the newly developed regression equations, the correlation coefficients between the sum of the mandibular incisors and the sum of the canine and premolars were 0.709 (for lower) and 0.539 (for upper) in subjects. CONCLUSIONS: Tanaka and Johnston overestimate the actual size for Iranian teeth widths. Moyers method can be used at 65% probability level for male subjects and at the 75% and 85% level for upper arch and the 50% and 65% level for lower arch in female subjects.     

Design and implementation of a hybrid genetic algorithm and artificial neural network system for predicting the sizes of unerupted canines and premolars

The aim of this study was to develop a novel hybrid genetic algorithm and artificial neural network (GA-ANN) system for predicting the sizes of unerupted canines and premolars during the mixed dentition period. This study was performed on 106 untreated subjects (52 girls, 54 boys, aged 13-15 years). Data were obtained from dental cast measurements. A hybrid GA-ANN algorithm was developed to find the best reference teeth and the most accurate mapping function. Based on a regression analysis, the strongest correlation was observed between the sum of the mesiodistal widths of the mandibular canines and premolars and the mesiodistal widths of the mandibular first molars and incisors (r = 0.697). In the maxilla, the highest correlation was observed between the sum of the mesiodistal widths of the canines and premolars and the mesiodistal widths of the mandibular first molars and maxillary central incisors (0.742). The hybrid GA-ANN algorithm selected the mandibular first molars and incisors and the maxillary central incisors as the reference teeth for predicting the sum of the mesiodistal widths of the canines and premolars. The prediction error rates and maximum rates of over/underestimation using the hybrid GA-ANN algorithm were smaller than those using linear regression analyses.