Congenitally missing permanent canines in a sample of Chinese population: a retrospective study.

Background: Congenitally missing permanent canines (CMPC) have a significant impact on function and aesthetics. The prevalence is low, and the availability of rigorous studies on this issue in China is limited. This study was designed to investigate the prevalence and distribution of CMPC in patients and concomitant anomalies. Additionally, we aimed to compare the prevalence of CMPC between two age groups.

Methods: A total of 10,447 patient's panoramic radiograph (PR) images from August 2021 to December 2023 were reviewed and data regarding the location and number of CMPCs were recorded. Age and gender were obtained from the clinical records. Additionally, concomitant anomalies such as persistent primary canines, congenitally missing other permanent teeth, supernumerary teeth and microdontia were also recorded in patients with CMPC. 10,447 patients were divided into two groups: group A (< 121 months of age) and group B (≥ 121 months of age) to record the number of patients with CMPC. The data were presented as counts (n) and percentages (%), and statistically analysed using the Chi-square test.

Results: The average age of patients with CMPC was 9.2 years, with a prevalence of 0.69% (n = 72). The difference between genders was not statistically significant (p = 0.950). The prevalence of CMPC in group B (1.08%, 26/2400) was significantly greater than that in group A (0.57%, 46/8047) (p = 0.008). 89.42% (93/104) of the missing permanent canines had visible primary canines in patients. CMPC were more likely to occur in the maxilla (91.67%) than in the mandible (6.94%) (p<0.001). No significant difference was found between the left and right sides (p = 0.844). With respect to concomitant anomalies among those with CMPC, 22 patients had 58 congenitally other permanent teeth missing, 3 patients had 3 supernumerary teeth, and 12 maxillary lateral incisors from 7 patients presented with microdontia.

Conclusions: The prevalence of CMPC was 0.69%. CMPC were more likely to occur in the maxilla in the presence of persistent primary canines and were not influenced by gender or side. Early panoramic radiographs can improve the detection rate of CMPC, thereby facilitating prompt intervention and timely management.