Mixed dentition analysis for black Americans.

The mixed dentition analysis described by Moyers, and later validated by Tanaka, was performed on 80 American blacks to compare prediction equations between Caucasians and blacks. For the black sample, separate regression formulas were determined for the 39 males and 41 females and the combined black sample. Although sexual dimorphism of tooth size was not a consideration in the Moyers prediction charts, this research evaluated the effect of sexual dimorphism in the mixed dentition analysis. Regression equations were generated by the method of least squares, and the 2-tailed t-test was used to determine significant differences between 2 equations for the same arch. The findings include a significant difference for the mandibular regression equation for black males when compared with (1) the Tanaka equation for Caucasians, and (2) the regression equation for black females. Maxillary regression equations were not significantly different between the Caucasian and black samples or between black males and females. Frequently in pediatric dental practice the dentist must manage and guide the mixed dentition of a child into the permanent occlusion, with space available and tooth size intimately being involved in treatment planning. A reliable method of determining tooth size while the tooth is still within the dental follicle and surrounded by bone will aid treatment planning. There have been reports in the literature on methods for predicting the mesiodistal dimension of unerupted canines and premolars in Caucasians. 1-11 Sexual dimorphism has been investigated with respect to tooth size prediction, 12,~3 and radiographic 4,5, 7,14-18 as well as combination19,2° techniques are available for Caucasians. There are, however, few reported studies concerning the mesiodistal dimension of the buccal teeth in the American black 21-23 and only 1 study to evaluate the widely used mixed dentition analysis of Moyers for the black child. 24 Sexual dimorphism was not considered for this investigation. 25 Recent comparisons among the alternative methods for prediction of tooth size in Caucasians has been researched. 26-28 In the present study, a statistical analysis for blacks was performed and the sample also was segregated into male and female groups to determine the effect of sexual dimorphism of tooth size on the mixed dentition analysis. Methods and Materials The materials for this study consisted of stone casts of the dentition of 80 black children (39 males, 41 females) who presented with complete eruption of permanent mandibular incisors, canines, and premolars, as well as maxillary canines and premolars. These children were selected from the population of patients seen at the Children’s Hospital of Pittsburgh Dental Clinic. Criteria for selection were based on complete fulfillment of the following. 1. The patient had to be of probable American black heritage for at least 2 prior generations. 2. None of the teeth to be measured could show proximal caries, restorations, or fractures as determined by bite-wing radiographs. 3. The patient had to be free of systemic disease; however, 1 female was diagnosed with juvenile diabetes mellitus at age 12. 4. There was to be no clinical evidence of hypoplasia or hypocalc~fication to the teeth being measured. 5. A maximum of 19 years of age was used in order to preclude any discrepancies based on secular trends or significant proximal wear. All individuals selected for this study were between 12 and 17 years without prior orthodontic treatment. Impressions were made with a fast-set irreversible hydrocolloid material a and poured with white dental stone within 1 hr. The mesiodistal width of a tooth was obtained by a jeltrate®_L. D. Caulk Co., Milford, DE. 226 MIXED DENTITION ANALYSIS: Frankel and Benz Table 1. Mean, Range, and Standard Deviation of Tooth Sizes from Black Population Sample from this Study in Millimeters