Determination of downs hard tissue cephalometric norms for Himachali Mongoloid tribes

Objective

The purpose of this study was (a) to establish hard tissue cephalometric norms for the population of Himachali Mongoloid tribes, (b) to study the sexual dimorphism in hard tissue cephalometric norms of this population and (c) to compare the Himachali Mongoloid norms with the norms established by Downs.

Material and method

Sixty Himachali Mongoloid subjects were selected on the basis of Angle’s Class I molar relationship, well aligned arches, full complement of teeth, having clinically acceptable facial esthetics, no previous history of Orthodontic treatment, subjects native of the tribal belt of Himachal Pradesh. Lateral head films were traced and Downs cephalometric parameters were recorded. Statistical analysis was done to compare the difference between the established norm and the norm established by Downs for the Caucasian population.

Result

Significant difference was seen in the Angle of convexity, with Himachali Mongoloid tribe population having a more forwardly positioned middle part of the face. This population had less steeper cant of occlusal plane, more acute interincisal angle, more inclined lower incisors in relation to the mandibular and the occlusal plane and more forwardly positioned maxillary incisor in relation to the A-pog line.

Conclusion

These findings suggested that ethnic differences in the facial traits exist and awareness of dentofacial pattern of each ethnic group will ensure better success of the treatment in establishing optimal facial harmony.