ABSTRACT
Aim: This study was conducted to establish the Bolton’s ratios’ norms ((The mean Overall Ratio (OR) and Anterior Ratio (AR) norms)) in 100 Karnataka subjects and to compare it with the overall ratio and anterior ratio of the Bolton’s analysis which would be an aid in diagnosis and treatment planning of orthodontic cases. It will also help in determining functional and esthetic outcome of the case. Methodology: Epidemiological survey was carried out for 100 subjects (50 males and 50 females), 14-25 years of age. The study groups were from Karnataka state in India. Every individual was assessed for occlusal traits and good quality impressions were taken for 100 selective individuals. Mesiodistal tooth dimensions were measured from right first permanent molar to left first permanent molar in maxillary and mandibular arches. Measurements were taken using digital vernier caliper. Anterior and overall ratio were calculated for each model. Data was statistically analysed by using statistical package for social sciences (SPSS) software. Results: The results showed that the overall ratio was 92.23 for males and 91.78 for females. The anterior ratio was 77.87 for males and 77.69 for females. The study indicated that there was statistically significant difference between the overall ratio and anterior ratio of Karnataka subjects and Caucasian subjects. Conclusion: The study concluded that inter arch tooth size a relationship varies and are specific.
ABSTRACT
The purpose of this study was to measure the average tooth size of Korean with normal occlusion. According to the study, the average tooth ratios between the upper and lower teeth which could assure the proper ovebite, overjet and good interdigitation were calculated. The normal occluson sample of this study consisted of 43 Korean male adults and 51 Korean female adults. Among them, 22 Korean male adults and 51 Korean female adults were from KAO(Korean Association of Orthodontists), 21 Korean male adults were from Department of Orthodontics, College of Dentistry, Yonsei University. The results from this study were as follows : 1. The average tooth size of Korean Norm classified by male and female was measured. 2. The average tooth size of Korean male adults with normal occlusion was significantly larger than that of Korean female adults except upper and lower first molars.(p<0.05) 3. The tooth ratio which could predict the proper overbite and overjet in anterior teeth and proper occlusion in posterior teeth was calculated. 1) Sum of inciosrs = 4 : 2.97 2) Neff's anterior coefficient = 1.22 3) Bolton's anterior ratio = 78.29%, overall ratio = 91.14% 4. A positive correlation was observed between the sum of lower anterior incisors and the sum of unilateral canine and premolars in each jaw. Based this correlation, the regression equation was made which could predict the sum of unerupted unilateral canine and premolars in mixed dentition. 1) Sum of unilateral unerupted upper canine and premolars' width = 10.435018 + 0.513346x(sum of lower 4 incisors' width) 2) Sum of unilateral unerupted lower canine and premolars' width = 9.654002 + 0.502565x(sum of lower 4 incisors' width)