Frequencies of Clinically Significance Tooth Size Discrepancies Among Different Ethnicity in Malaysia

Abstract

Abstract Background: The Bolton analysis is one of the commonly used tooth size analysis or diagnostic tools in deriving a treatment plan for orthodontic patient. Many studies have indicated and concluded that normal measurements for one group should not be considered normal for other ethnic groups. The aims and objectives of this study were to investigate the applicability of Bolton’s ratios in orthodontic population of Malaysian main ethnics; Malay, Chinese and Indians. Comparisons were made in term of size and distribution of tooth size discrepancy in Malaysian orthodontic population and the findings were converted in terms of millimetres. Methods: Hundred fifty pre-orthodontic study casts comprised of 52 Malay, 54 Chinese and 44 Indian patients were selected. Digital callipers (Fowler Pro-Max) link to Hamilton Tooth Arch Software were used to measure the tooth width and ratios. Statistical analysis was carried out to test for gender differences (independent t-test), to identify the effects of malocclusion and ethnic groups (Two-way ANOVA) and to compare the means of current study with Bolton’s standards (one sample t-test). Results: This study showed that there was no significant difference between genders of sample of each ethnic. There was no correlation found between ethnic groups and malocclusion classes. There was a significant difference when comparing Bolton values with Malay sample for both ratios. It was found that more Malay subjects presented with maxillary excess contrary to Chinese and Indian which presented more maxillary deficiency for the anterior and overall ratio. Conclusion: there were 20.7% of Malaysian sample fall beyond suggested 2SD of clinically significant for anterior ratio and 4.7% which fall in this definition for overall ratio. The Bolton standards can be applied to Malaysian Chinese and Indians but not to Malays ethnic group. Subsequently, a specific standard should be used for the Malays orthodontic population.