A Bolton Analysis Comparison of Hispanic vs. Caucasian Samples in Indianapolis, Indiana

Abstract

Although many studies examining tooth size discrepancy have been conducted, many were originally done on unknown populations and genders. They were also conducted on Class I ideal occlusions. Since that time, there have been many studies of the Caucasian population, but little has been done to compare the differences between Caucasian and Hispanic patients. The objective of this study was to establish whether there is a greater incidence of Bolton tooth mass discrepancies in the Hispanic population than in the Caucasian population of Indianapolis, Indiana. Secondly, the objective was to examine possible differences in the incidence of tooth mass discrepancy according to gender and dental malocclusion in the same sample. A sample of 292 pretreatment casts was measured to determine the incidence in both populations. The sample was composed of 146 Caucasian patients and 146 Hispanic patients. The patient sample was composed of 86 Caucasian females, 60 Caucasian males, 87 Hispanic females, and 59 Hispanic males. Patient's ethnicity was defined by photos and patient history. Individuals with a known mixed ethnicity were excluded. The sample was taken from patients in both the pre- and postdoctoral clinics at Indiana University School of Dentistry Section of Orthodontics, and the offices of selected private practitioners. Mesio-distal width of all teeth from first molar to first molar was measured with the mesio-buccal and disto-buccal contact areas normally being the widest area. The inter-incisal angle was evaluated utilizing lateral cephalometric radiographs. The molar and cuspid classification, overjet, overbite, and maxillary central incisor anterior-posterior dimension was measured from the dental casts. Results demonstrated that overjet, overbite, interincisal angle, molar class, and cuspid class did not have a significant effect on the Bolton discrepancy with each gender or between the two ethnic groups. Ethnicity did have a significant effect on the overall and anterior Bolton discrepancy with the ratio the Hispanics showing a significantly higher proportion of cases outside normal. Exploratory analysis also demonstrated which teeth were most discrepant. Clinicians are faced daily with the challenge of trying to produce ideal occlusions with optimal esthetics. Tooth mass discrepancies present an impediment to the clinician in trying to achieve this goal. By studying malocclusions common to a population, the clinician can more effectively treat his/her patients by being aware of potential problems that might compromise the final outcome. With the burgeoning Hispanic population in the US, this study was indicated using the Hispanic population as a patient base to ascertain how commonly used norms relate to the Hispanic population. This study demonstrated Hispanics have a significantly greater proportion of patients with a significant Bolton discrepancy. Being aware of this will allow the clinician to treat his/her patients more effectively and obtain an optimum esthetic and functional result.