Morphological and Numerical Characteristics of the Southern Chinese Dentitions. Part IV: Traits in the Primary Dentition

Aim: To investigate the prevalence of twelve dental traits in the primary dentition of southern Chinese and compare to these figures with those from different ethnic groups. Materials and Methods: The material used in the study consisted of study casts collected from 936 randomly selected 5year-old children (493 males and 443 females) in Hong Kong. The anomalies were assessed using diagnostic criteria that have been most often been cited in the published literature. Results: Of the twelve dental traits studied, the prevalence figures of seventh accessory cusp (89.0%), distal trigonid crest (33.5%) and metaconid ridge (84.0%) in the southern Chinese children were higher than reported for other ethnic groups. The prevalence figures for distinct and strong types of protostylid (13.7% and 0.9%), in this study, were also found to be higher than for other populations. However, the prevalence of deflecting wrinkle was 63.0% which was the lowest reported for Mongoloids. The prevalences of double lingual tubercle (22.5%) and “Y” type of occlusal groove pattern (80.1%) in southern Chinese children were found to be lower then for other ethnic groups. Conclusion: Higher prevalences of seventh accessory cusp, distal trigonid crest and metaconid ridge can be considered to be characteristics of the southern Chinese primary dentition.