[A survey of number and morphology anomalies in permanent teeth of 6 453 youths between 17 to 21 years old].

OBJECTIVE

To investigate the status of number and morphology anomalies in the permanent teeth.

METHODS

A survey of anomalies of number and morphology in the permanent teeth was carried out in 6 453 students who were 17 to 21 years old in 3 colleges during 2002 to 2004. Chi-square test was used to analyze the sex distribution, the involved tooth types and the associated anomalies.

RESULTS

The overall prevalence of dental number and morphology anomalies was 16.07%. The prevalence rates of peg-shape (conical) tooth, dens evaginatus and hypodontia were higher in females compared to males (P < 0.05). Dens evaginatus and peg-shape teeth often involved maxillary lateral incisors, Dens evaginatus often involved mandibular second premolars. Fused teeth and hypodontia often involved mandibular incisors. The prevalence of hypodontia coincident with peg-shaped teeth was higher than other associated anomalies (P < 0.01).

CONCLUSIONS

The result was similar to other investigations, but peg-shape teeth and dens evaginatus were more prevalent in females than in males.