Root canal and nasopalatine canal morphology in a Guangxi population: a cone-beam CT study on regional variations.

OBJECTIVE: To characterize the root canal morphology of premolars, mandibular second molars and the anatomical parameters of the nasopalatine canal (NPC) in the Guangxi Zhuang Autonomous Region, China, using cone-beam computed tomography (CBCT), and to explore regional variations. METHODS: This retrospective study analyzed CBCT imaging data from a large population in Guangxi, focusing on the anatomical characteristics of maxillary and mandibular premolars, mandibular second molars, and the NPC. High-resolution CBCT slices and three-dimensional reconstruction techniques were used to quantitatively assess the number, classification, and symmetry of root canals, as well as the linear parameters of the NPC. Statistical analyses were conducted to examine correlations between anatomical variations and factors such as gender, age, and tooth position. RESULTS: A total of 550 patients were included. The results shown that maxillary first premolars have a high prevalence of multiple canals, with a rate of 86.5%. Females exhibited more complex premolar canal systems than males (ρ = 0.180, P < 0.001). C-shaped canals in mandibular second molars occur at a rate of 39.8%, with 28.0% showing bilateral symmetry. It was negatively correlated with the presence of multiple canals in premolars, as evidenced by a correlation coefficient of ρ=–0.141 (P < 0.001). NPCs were predominantly of the single-canal type (75.6%). Canal diameter increased with age (ρ = 0.227, P < 0.001) and was larger in males (P < 0.001). CONCLUSIONS: The Guangxi population exhibits substantial premolar canal variation and a notable prevalence of C-shaped canals in mandibular second molars, indicating distinct regional anatomical patterns. Preoperative CBCT evaluation is essential for endodontic and implant procedures. The age-related increase in NPC diameter provides important anatomical considerations for anterior maxillary implant safety.