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

ABSTRACT

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.

The material used in the study consisted of study casts collected from 936 randomly selected 5- year-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.

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.

Higher prevalences of seventh accessory cusp, distal trigonid crest and metaconid ridge can be considered to be characteristics of the southern Chinese primary dentition.

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