Intermaxillary Mesiodistal Tooth Size Ratio of Permanent Dentition

Although the Bolton tooth size analysis is an important diagnostic tool for orthodontic patients, there is lacking of information about the tooth size ratios of Bama (Major race of Myanmar). Objective: The purpose of this study was to determine the intermaxillary mesiodistal tooth size ratio of Bama. Methods: It was conducted on 43 male and 55 female Bama subjects, having Angle's class I occlusion, normal overjet and overbite. The mesiodistal diameter of individual tooth were calibrated by Mitutoyo digimatic caliper from left first molar to right first molar on both maxillary and mandibular stone casts. Then (1) anterior, (2) posterior and (3) overall tooth size ratios were calculated by dividing (1) sum of mandibular anterior 6 teeth by sum of maxillary anterior 6 teeth, (2) sum of mandibular premolars and first molar by sum of maxillary premolars and first molar and (3) sum of mandibular 12 teeth by sum of maxillary 12 teeth. Results: The mean anterior tooth size ratio was 78.43, posterior tooth size ratio was 103.08 and overall tooth size ratio was 91.07. There was no significant difference between the tooth size ratios of male and female groups (t test, p>0.05). Moreover, the overall tooth size ratio of Bama (91.07) was not significantly different from Bolton's value (91.3) (t test, p>0.05). However, the anterior ratio of Bama (78.43) was significantly different from that of Bolton (77.2) (t test, p<0.05). Conclusion: So, this study generates certain reference for Bama population to be used for orthodontic treatment.