[Investigation of teeth number and morphology abnormalities in children at the mixed dentition stage]

This study aims to investigate the prevalence and distribution of teeth number and morphology abnormalities in Chinese pediatric patients' permanent teeth at the mixed dentition stage by performing panoramic radiographs analysis.

A total of 4 347 panoramic radiographs of pediatric patients aged 5 years to 15 years who were admitted to the hospitals from September 2011 to September 2013 were reviewed. The presence of teeth number and morphology abnormalities were recorded as follows: congenitally absent teeth, supernumerary teeth, odontoma, microdontia, fused teeth, dilaceations, and cusp deformity. SPSS 16.0 software was used for statistical analysis.

The prevalence of teeth number and morphology abnormalities in pediatric patients' permanent teeth was 31.79% (1,382/4,347). The prevalence was higher in males. Significant difference between the genders was observed (P < 0.05). Tooth agenesis, the most frequent dental anomaly (15.00%, 652/4,347), was considerably common in females; supernumerary teeth (12.61%, 548/4,347) followed, which was significantly common in males. Both differences were statistically significant (P < 0.05). The levels of prevalence of both microdontia and dilacerations were 4.00% (174/4,347) and 2.16% (94/4,347). The prevalence of cusp deformity, odontoma, and fused teeth were relatively low at 0.74% (32/4,347), 0.51% (22/4,347), and 0.39% (17/4,347), respectively.

The prevalence of teeth number and morphology abnormalities in children's permanent teeth at the mixed dentition stage is apparently high. Tooth agenesis and supernumerary teeth are the most frequent. Panoramic radiograph is an efficient method for the early diagnosis of teeth number and morphology abnormalities. This method can assist pediatric dentists to formulate treatment plans for children at the appropriate time.