Characteristics of premaxillary supernumerary teeth in non-syndromic Chinese children

This study aimed to identify the characteristics of supernumerary teeth (ST) in the premaxillary region of non-syndromic Chinese children and analyse their association with eruption. Oral examination and periapical radiographs were used to diagnose patients with ST at first visit. Clinical information was collected including age, gender, dentition of premaxillae, as well as number, morphology, orientation, and eruption status of ST based on periapical radiographs for analysis. Frequencies of characteristics were counted and influences of ST numbers and eruption status were analysed. Pearson Chi-square tests, Fisher’s exact test and binary logistic regression were used to analyse differences in frequency. A total of 2864 premaxillary ST were found in 2119 children, with a male to female ratio of 3.26:1 (M: F) and an average age of 7.0 years (first quartile 5.7 years, median 6.9 years, third quartile 8.0 years). Most of the cases (98.3%) were with partial or no permanent teeth eruption in premaxillae. More than half (65.6%) of the cases had one ST. Patients with partial permanent teeth eruption (β = -0.609, OR = 0.544) or gender of female (β = -0.247, OR = 0.781) had negative relationship with multiple ST occurrence. Morphology of conical, tuberculate, and supplemental accounted for 77.3%, 20.6%, and 2.1% of all ST, respectively. More than half of the ST (54.2%) had a normal orientation. Tuberculate- or supplemental-shaped ST were more found in normal orientation. 990 (34.6%) ST had erupted and the peak of eruption occurred around the age of 5 years old (46.5%). Orientation of inverted (β = -3.980, OR = 0.019), horizontal (β = -1.150, OR = 0.318), and sagittal (β = -1.030, OR = 0.356) was negatively related to ST eruption. ST in the premaxillae of children and adolescents under 14 years old were more found in males. Most cases had one ST. Conical shaped and normal orientated ST were most common type. ST with tuberculate and supplemental-shaped were more found in normal orientation. The peak of ST eruption occurred around the age of 5 years old and orientation of inverted was the most risk factor for ST eruption.