Micro-computed tomography evaluation of the prevalence and morphological features of apical bifurcations

BACKGROUND/PURPOSE: Apical bifurcation, as a common variation in root canal morphology, has great clinical significance for root canal treatment. The aim of this study was to investigate the morphological characteristics of the apical bifurcated canal in Chinese teeth based on a large sample size using micro-CT. MATERIALS AND METHODS: One thousand and four hundred Chinese permanent teeth were scanned by using micro-CT with the resolution of 15 μm. The number of apical bifurcations was calculated and the vertical distance of apical bifurcations was recorded. The diameter and angles of the apical bifurcated canals were further measured using the centerline algorithm method. RESULTS: Ninety-two apical bifurcations were detected in 15 anterior teeth, 27 premolars, and 46 M. The median vertical distance of apical bifurcations was 1.1 mm from the apex (ranging from 0.3 to 3.5 mm). Ninety-eight-point nine percent of the apical bifurcations were located less than 3 mm from the apex. The smaller angle of apical bifurcated canals with the main canal was 20.4°. The larger angle of the apical bifurcated canals with the main canal was 32.9°. The median diameter of apical bifurcated canals was 195.0 μm. CONCLUSION: A high prevalence of apical bifurcation can be detected in the human permanent teeth, especially in posterior teeth. Most apical bifurcations locate within the apical 3 mm with a diameter more than 200 μm.