Variability and Patterning in Permanent Tooth Dimensions among Four Ethnic Groups from the North-eastern States of India

Abstract

Background and Objectives. Tooth dimensions provide a wealth of information about human evolution and have forensic and clinical dentistry applications. The present study aimed to assess the mesiodistal (MD), buccolingual (BL), and cervico-incisal (C-I) dimensions of permanent teeth up to the second molars in four ethnic groups of North-eastern India and to compare them with existing standard data. Methods. The study was a comparative cross-sectional study among four different ethnic groups of North-east India among the age group of 20-30 years. Dimensions of the maxillary and mandibular teeth were measured with a digital Vernier calliper using the dental casts of 50 male and 50 female subjects from each of the four ethnic groups under study. The data were statistically analyzed using a Student’s $t$ -test and one-way analysis of variance. Statistical significance was set at $p<0.05$ . Results. The tooth dimensions of all four ethnic groups were significantly lower than the standard values except for the MD dimension of the maxillary second molars of the Singpho group (9.13 mm vs. 9.0 mm); mandibular central incisors of the Meitei group (5.01 mm vs. 5.0 mm); and mandibular lateral incisors of the Meitei, Ao, and Singpho groups (>standard value of 5.5 mm) and BL dimension of the mandibular first premolars of the Meitei and Ao groups (>standard value of 7.5 mm); mandibular second premolars of the Meitei and Singpho groups (>standard value of 8.0 mm); and mandibular second molars of the Ao group (10.04 mm vs. 10.0 mm). In some instances, the comparative analysis revealed group variations in different tooth dimensions among the four ethnic groups ( $p<0.05$ ). Conclusion. Variations were observed in the tooth dimensions among the four ethnic groups and within the same population. Unlike other parts of India, the North-eastern population belongs to a distinct ethnic race of indigenous people of East Asia, Southeast Asia, and the Arctic region of North America. Hence, population-specific data for India’s North-eastern region are necessary for forensic odontology, dental anthropology, routine dental practice, and effective treatment planning.