Study of tooth loss in an adolescent Brazilian population

Abstract Data concerning tooth loss in developing countries may indicate the dental health status in young people and serve as baseline data for evaluation of future dental health programs. The study population consisted of 304 schoolchildren (145 males, 159 females) from Belo Horizonte, M.G. Brazil. The mean age was 14.5, ranging from 13 to 16 yr. The number of teeth already lost and teeth indicated for extraction were assessed from two posterior bitewing radiographs and one frontal color photo which were obtained from all participants. The results showed that 2/3 of the studied population had lost one or more permanent teeth. The average number of missing teeth was 1.8 in both males and females. Of the various teeth, the mandibular first molars had most frequently been lost. Differences between the sexes concerning amount and pattern of lost teeth were small.     

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.     

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.     

Prediction of the size of un-erupted permanent cuspids and bicuspids in a Saudi sample: a pilot study

The purpose of this study was to produce an estimated equation for the prediction of unerupted cuspids and bicuspids for the Saudi population. In this study, dental casts of 65 Saudi subjects (37 males and 28 females) were used. The subjects' age ranged from 18 to 25 years. The mesiodistal width of all permanent teeth was measured. The data was subjected to regression analysis. Results showed the Tanaka and Johnston equations overestimate the predicted tooth width of the un-erupted cuspids and bicuspids in Saudis. Results showed the predicted tooth width of Saudis (males and females) is closer to the 50% level of confidence in Moyer's chart. Multiple regression equations were estimated including the sex factor. Accordingly, two equations were estimated for the prediction of the tooth width of the un-erupted cuspids and bicuspids for the Saudi males and females. Based on the results, it can be concluded the 50% data is more accurate than the commonly used percentage Moyer's table (75%) when both sexes are combined. Further studies are needed to confirm the findings of this study.     

The B.S.S.O. M.Orth. prize of the Royal College of Surgeons of England: 1997.

Abstract

Objectives: To test the use of Moyers prediction method and Tanaka and Johnston’s equations for use in a Nepalese population and to construct new probability tables and prediction formulae based on the actual tooth sizes in a sample of the Nepalese population.

Design: Cross-sectional.

Source and setting: Dental, medical and nursing science students at the B.P. Koirala Institute of Health Sciences, Dharan, Nepal.

Subjects and methods: The sample consisted of 100 Nepalese males and 100 females aged between 17 and 23 years. Subjects without any previous orthodontic treatment, fully erupted permanent teeth and with no dental anomalies were recruited. Dental study models were taken and measurements of the mesio-distal widths of teeth were carried out using digital caliper. The measured values were compared with predicted values derived from Moyers method and Tanaka and Johnston equations. Independent t tests were used to examine differences between genders. Correlation coefficients and linear regression equations were used to compare the actual Nepalese tooth widths with predicted values

Results: Moyers method at 50% tends to underestimate the actual width of the canine and premolars in males by 0.3 mm and overestimate the width in females by 0.2 mm. The Tanaka and Johnston method tends to overestimate the actual width of the canine and premolars in both males (0.7 mm) and females 1.0 mm.

Conclusion: The newly developed regression equations are more accurate for prediction of width of unerupted permanent teeth in a Nepalese population. Further studies are required based on larger sample size, to confirm the applicability of the new regression equations proposed.     

An adaptation of the Moyers mixed dentition space analysis for a Western Cape Caucasian population.

200 dental plaster casts of Western Cape Caucasoid subjects, all of whom were under the age of 21 years, were used in this study. Mesio-distal measurements (MD lengths) were obtained of all the teeth, disregarding the third molars. This data was used to develop regression equations, for maxillary and for mandibular arches, to enable the prediction of the mesio-distal lengths of the canine and two premolars. The study identified the sum of the MD lengths of the permanent lower incisors as the best predictor. It appears that separate predictions for male and female are not warranted. The equations and the predicted values were compared with those of Moyers (1973 and 1988) and some significant differences were found. The Prediction Tables will be useful in analysis of the mixed dentition phase in patients from this population group.     

The lower incisors as a predictor for the size of unerupted canine and premolars in the Iranian ethnicity

The purpose of this study was to find the correlation coefficients between the mesiodistal widths of the permanent mandibular incisors and the permanent canine and premolars for each quadrant and establish a regression equation for prediction of the sum of canine and premolars based on the dimension of the lower incisors. 90 patients 12–20 years old (45 females and 45 males) were selected. The mesiodistal crown diameters of the permanent teeth were measured. The correlation coefficients between the permanent mandibular incisors and the permanent canine and premolars sizes varied from 0.63 to 0.8. An Iranian mixed dentition analysis based on the Tanaka and Johnston method was constructed with linear regression equations; for maxillary arch y = 6.3 + 0.65x (SEE = 0.8 mm) and for mandibular arch y = 5.1 + 0.67x (SEE = 0.8 mm). No significant sexual dimorphism was found in tooth sizes. This study revealed that Iranian population has smaller teeth than white North American. We found that prediction equations of Tanaka and Johnston or Moyers charts cannot accurately predict the size of buccal segment in Iranian population.     

Relationships between dental and skeletal maturity in Turkish subjects

The aim of this study was to investigate the relationships between the stages of calcification of various teeth and skeletal maturity stages among Turkish subjects. The samples were derived from dental panoramic and hand-wrist radiographs of 500 subjects (215 males and 285 females). Calcification of the mandibular canines, first and second premolars, and second and third molars was rated according to the system of Demirjian. To evaluate the stage of skeletal maturation of each hand-wrist radiograph, nine ossification events were determined according to the systems of Bj?rk, and Grave and Brown. Statistically significant relationships were determined between dental calcification and skeletal maturity stages according to Spearman rank-order correlation coefficients. Correlations between dental development and skeletal maturity ranged from .490 to 0.826 for females and .414 to .706 for males (P < .01). The second molar showed the highest correlation and the third molar showed the lowest correlation for female and male subjects. For both sexes, root formation of the canine as well as the first premolar was completed in the majority of the subjects at the MP3cap, PP1cap, Rcap stages. Because of the high correlation coefficients, this study suggests that tooth calcification stages from panoramic radiographs might be clinically useful as a maturity indicator of the pubertal growth period. It is appropriate to put these skeletal and dental maturation relationships into daily orthodontic diagnostic practice, when treating a Turkish patient.     

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)。     

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.     

The mesiodistal crown diameters of primary dentition in Indonesian Javanese children

Dentition analysis of primary teeth is necessary for recognising and correcting occlusal problems in every stage of dental development to enable normal adult occlusion. To do this, normative data of mesiodistal tooth crown diameters from the same ethnic population are needed. The aims of this study were to gather normative data of mesiodistal crown diameters of primary dentition in Indonesian Javanese children and to compare this normative data with published data of other ethnic populations. Dental casts of 160 males and 137 females with acceptable occlusion, aged 3.25-6.58 years, were taken in Yogyakarta, Indonesia. Mesiodistal diameter was measured as the distance between the anatomic contact points using calipers with accuracy to within 0.05 mm. Each measurement was taken twice on different occasions. The results indicated that the magnitude of asymmetry between right and left teeth was larger in distal teeth within a tooth field, larger in males than females, and larger in mandibular than maxillary teeth. The stability of mesiodistal tooth crown diameters was less in males than in females, and was most prominent in the mandibular central incisor. Sexual dimorphisms were found in, the lateral incisor and first molar in the maxilla, and the canine, first and second molars in the mandible. Compared with other ethnic populations, Indonesian Javanese falls between Hong Kong Chinese and Australian Aboriginal.     

Volume analysis of second molar pulp chamber using cone beam computed tomography for age estimation in Egyptian adults

AimThe present work aimed to evaluate age-related variations in the dental pulp chamber volume of second molars using cone beam computed tomography (CBCT) imaging, in order to establish a specific mathematical model for second molars and measure its accuracy, especially in the case of Egyptian adults.Subjects and methodsFrom 187 subjects between 21–50 years of age, CBCT images of 257 maxillary and 248 mandibular second molars were included. A mathematical model for human age estimation was established. An independent additional set of CBCT images was obtained to test the model''s accuracy.ResultsFor maxillary and mandibular teeth, R² for the pooled sexes were 0.51 and 0.52, and SEE were 5.92 and 5.71, respectively. A model for each sex was established, due to the significant difference between them, where R² was equal to 0.668 and 0.650 in males and 0.46 and 0.48 in females, concerning maxillary and mandibular teeth, respectively. When testing the validation samples, the mean absolute error (MAE) between the actual and estimated ages from the pooled sex model were 4.89 and 4.61 for maxillary and mandibular teeth, respectively.ConclusionThe pulp chamber volume of second molars is a relatively accurate indicator for age estimation in Egyptian adults.     

江苏地区正常的牙及牙弓测量研究

目的 测量125名江苏地区正常人群的模型,建立江苏地区正常牙及牙列指数的平均值。方法 选取正常模型125副(男61副,女64副),用电子游标卡尺测量牙冠宽度、牙弓宽度及长度、腭盖高度,对测量结果进行统计分析。结果 江苏地区正常人群的牙冠宽度、牙弓宽度及长度、腭盖高度均为男性大于女性,Bolton指数及Pont指数无性别差异。上下颌6个前牙牙冠宽度总和、全部牙冠宽度总和具有相关性,上颌中切牙与上颌前段牙弓宽度之间亦存在相关性,且建立了直线回归方程。结论 牙冠形态、牙列指数存在种族、地区和性别的差异,临床上应参照本民族、本地区的标准。     

下颌前牙唇侧骨壁厚度及倾斜角度对即刻种植术前设计的影响

目的: 利用锥形束CT（cone-beam CT,CBCT）对下颌前牙唇侧骨壁厚度及倾斜角度进行测量分析,为下颌前牙区的即刻种植术前设计提供参考依据。方法: 选取青岛大学附属医院口腔科135例（男67例,女68例）下颌恒牙列完整的CBCT资料,分别测量牙槽嵴顶处（P1）、牙根中点处（P2）、根尖处（P3）3个位点的唇侧骨壁厚度、下前牙长轴与牙槽骨长轴的角度。采用SPSS 23.0软件包对数据进行统计学分析。结果: 下颌中切牙、侧切牙、尖牙唇侧牙槽嵴顶处骨板厚度分别为（0.65±0.24）mm、（0.66±0.28）mm、（0.57±0.29）mm,根中处骨板厚度分别为（0.58±0.35）mm、（0.47±0.23）mm、（0.58±0.30）mm,根尖处骨板厚度分别为（3.45±1.28）mm、（3.87±1.25）mm、（4.60±1.32）mm;下颌中切牙、侧切牙、尖牙牙体长轴与牙槽骨长轴角度分别为5.43°±2.30°、7.22°±3.12°、6.28°±2.65°;相同牙位左右侧之间、不同性别之间各测量值之间无显著差异。结论: 下颌前牙唇侧骨壁厚度菲薄,下颌前牙倾斜角度较小,可为下颌前牙区的即刻种植术前设计的制定提供参考依据。     

Primary Canine Hypoplasia in Head Start Children

Primary canine hypoplasia is an incomplete or defective development of the enamel matrix. The lesion is located on the labial surface and is seen more frequently on mandibular teeth. The purpose of this preliminary study was to determine the prevalence of this lesion among Head Start children. During a dental needs assessment of Mississippi Head Start children, 371 children from 11 centers were examined for this lesion. Of the centers, four were located in optimally fluoridated communities, and six were located in fluoride-deficient communities. Ages ranged from three to five years. There were 206 males and 165 females, 334 black and 37 white children. At ten centers all children were black, while all children at one center were white. Results indicated no significant differences in the black population between fluoridated (38.2%) and fluoride-deficient (36.3%) communities (P = .729) or between males (36.8%) and females (37.6%) (P = .877). When data were collapsed on sex and fluoridation status, the racial differences were highly significant (P = .001). The prevalence rate of dental caries associated with primary canine hypoplasia was 26.0 percent. These preliminary data indicate that the presence of primary canine hypoplasia may result in an increased potential for the tooth becoming carious.     

The Prevalence of Three-rooted Mandibular Permanent First Molars in a German Population

The purpose of this retrospective study was to assess the prevalence of three-rooted mandibular first molars among a German dental school patient population. A total of 800 patients' full-mouth periapical radiographs were screened, and, out of these, 524 patients possessing at least one mandibular first molar were selected. The radiographs of these cases were evaluated under optimal conditions using double magnifying glasses. The incidence of three-rooted mandibular first molars and the correlation between left- and right-side occurrences and between males and females were recorded and analyzed using the chi-square test. A total of 1,024 mandibular first molars were evaluated. Left molars comprised 500 teeth and right molars 524 teeth. Seven patients were found to have a three-rooted mandibular first molar, three females and four males (p = 0.981). The overall incidence of patients with three-rooted mandibular first molars was 1.35%. All three-rooted molars occurred unilaterally. The prevalence of teeth showing an extra root from all teeth examined was 0.68%. The right first molar had an incidence of 0.57% and the left molar of 0.80%, respectively (p = 0.953). In conclusion, the occurrence of three-rooted mandibular first molars among this German population was rare.     

Metric and morphologic characteristics of the dentition in beta thalassaemia major in man.

Twenty-two thalassaemia major patients (11 males and 11 females) and their parents and their healthy siblings were examined, dental impressions taken in alginate and casts in plaster were studied. Thalassaemics were compared with like sexed parents and siblings, many of whom were affected by beta thalassaemia minor. Morphological traits of the teeth were examined. Length (M-D) and width (B-L) of the teeth were measured and comparisons made between the right teeth of thalassaemics and parents and between the right teeth of thalassaemics and siblings. Right-left asymmetry was also compared for thalassaemics, parents and sibling groups.The main differences found were: (1) More fissures, pits, tubercles and other elevations and prominences in the thalassaemics. (2) Significantly smaller teeth (p < 0.01) for thalassaemics (males) as compared with their siblings in the maxillary B-L dimension and the mandibular M-D dimension and in the females in the mandibular BL dimension (p < 0.03) but significantly larger teeth (p < 0.01) for thalassaemic females in the maxillary M-D dimension as compared with their sisters, but not in comparison with tooth size in their mothers. (3) Second molars in both sexes were greatly reduced in size. (4) Teeth of males were affected more than females. This was reflected in both tooth size and morphology.     

Timing of permanent tooth emergence in Danish children

abstract Mean times of emergence of the permanent teeth, except the third molars, and mean times of onset of specific dental stages were studied cross-sectionally in nearly 8,000 Danish children. In both sexes, a tendency for grouped emergence was observed, the teeth within a group showing similar mean times of emergence. The following groups were distinguishable: (1) the first molar in each jaw and the mandibular central incisor, (2) the maxillary central and mandibular lateral incisor, (3) the mandibular canine and the first premolar in each jaw, and (4) the maxillary canine and the second premolar in each jaw. The sex difference in emergence timing ranged from 2–11 months. In Denmark, the first visit to the Child Dental Services usually takes place when the children enter school in the year they attain the age of 7 years. The present findings indicate that, in order to include the initial phase of permanent tooth emergence, organized dental care should be introduced at least 1 year earlier.     

Timing of permanent tooth emergence in Danish children

abstract Mean times of emergence of the permanent teeth, except the third molars, and mean times of onset of specific dental stages were studied cross-sectionally in nearly 8,000 Danish children. In both sexes, a tendency for grouped emergence was observed, the teeth within a group showing similar mean times of emergence. The following groups were distinguishable: (1) the first molar in each jaw and the mandibular central incisor, (2) the maxillary central and mandibular lateral incisor, (3) the mandibular canine and the first premolar in each jaw, and (4) the maxillary canine and the second premolar in each jaw. The sex difference in emergence timing ranged from 2–11 months. In Denmark, the first visit to the Child Dental Services usually takes place when the children enter school in the year they attain the age of 7 years. The present findings indicate that, in order to include the initial phase of permanent tooth emergence, organized dental care should be introduced at least 1 year earlier.