Analysis of Interarch Tooth Size Relationship in Nepalese Subjects with Normal Occlusion and Malocclusions

Abstract

Introduction A proportional relationship between the maxillary and mandibular teeth size is required for achieving good finish with proper overjet and overbite postorthodontic treatment. The aims and objectives of this study were to determine the anterior and overall Bolton's ratio in Nepalese population, to compare Bolton's ratio between subjects with normal occlusion, Class I malocclusion, and Class II malocclusion, to compare these results with Bolton's norm, and to determine the frequency of clinically significant (beyond 2 SD) tooth size discrepancy compared to Bolton's norm. Materials and Methods The study models of the subjects with normal occlusion and Angle's Class I malocclusion and Class II malocclusion and fulfilling the inclusion criteria were retrieved from department archives. An electronic digital caliper was used to measure mesiodistal tooth size of the maxillary and mandibular teeth anterior to the second molars. The study sample of 120 study models consisted of the normal occlusion group (n = 31), Class I malocclusion group (n = 47), and Class II malocclusion group (n = 42). These measurements were then used to obtain Bolton's ratio in three groups of subjects. Bolton's ratio of study groups was compared with each other and with Bolton's original ratio. Results The differences in tooth size ratio of the study groups were not significant statistically, when the groups were compared on the basis of malocclusion or gender. Statistically significant differences were exclusively observed between the study groups and Bolton's original sample for the anterior ratio. The frequency of the clinically significant tooth size ratio discrepancy was lower for the overall ratio (9.1%) compared to the anterior ratio (22.5%). Conclusions Bolton's analysis on the Nepalese population sample shows that there was no significant difference observed on the anterior and overall tooth size ratios when these were compared based on Angle's malocclusion classes or gender. The clinically significant anterior tooth size discrepancy was more prevalent than that of the overall ratio.

Bolton tooth size discrepancy among different malocclusion groups in two different ethnic groups of Nepalese population

“…This is in accordance to the study done by O' Mahony et al 22 and Uysal and Sari 7 . This is also in accordance to study done by Mishra et al 20 in Nepalese population who compared the tooth size discrepancies in normal occlusion, Class I malocclusion and Class II malocclusion groups. Our study showed that there was no difference in both anterior and overall ratio as compared between males and females (Table 3).…”

“…Our study showed that there was no difference in both anterior and overall ratio as compared between males and females (Table 3). This is in agreement with the study done by Mishra et al 20 and Hong et al 23 in Nepalese population, M.A Ismail et al 24 and Mahmound NM et al 4 in Sudanese population, Endo et al 25 in Japanese population. This finding is in contrary to the study done in Nepalese population by Jaiswal A et al 26 They found the males have significantly higher anterior ratio as compared to females.…”

“…4 The anterior and overall ratios of both the ethnic groups as compared to Bolton's norms was higher but showed no significant differences (Table 2). The finding for the overall ratio was consistent with a study done in Nepalese population by Mishra et al 20 but the finding for anterior ratio was contradicting. The anterior ratio in the study done by Mishra et al showed significant greater ratio as compared to Bolton's norms.…”

Bolton tooth size analysis in a sample of Sudanese adults

“…The presence of (TSD) should be identified during the initial diagnosis and treatment planning stage. Thus appropriate mechanisms can be applied for resolving the discrepancy [7]. The treatment alternatives for tooth-size discrepancies include the restoration of relatively small teeth, interproximal stripping of relatively large teeth, modification of crown angulations or inclination, and extraction [4].…”

“…The perfect percentage of the upper and lower tooth material had been suggested by several studies [7][8][9][10]. Among these, Bolton's ratios are the most usually used methods to decide inter-arch (TSD) in orthodontic patients [11].…”