Morphological measurement and differential analysis of anterior teeth basing on cone beam computed tomography / 中华医学美学美容杂志

ABSTRACT

Objective:To investigate the labial surface angle and Collum angle of anterior teeth using cone-beam computed tomography (CBCT), and to provide guidance for proper setting of torque for avoiding alveolar fenestration and dehiscence.Methods:CBCT data of 200 patients (66 males, age ranging from 18 to 40 years, with average 26.7 years) were screened and imported into Invivo 5.4, the middle labio-lingual sections of anterior teeth were obtained, and the Collum angle and labial surface angle were measured respectively. One-way ANOVA was used to analyze the discrepancies of the two measurements among teeth. Pearson correlation analysis was performed to detect the association between the two measurements.Results:The Collum angles (labial surface angles) in upper central incisor, lateral incisor, canine and lower central incisor, lateral incisor and canine were 0.17±5.11° (15.50±2.91°), -5.67±5.74° (15.52±3.50°), -5.56±4.67° (20.07±3.66°), -3.97±4.49° (14.40±3.20°), -6.50±4.03° (14.76±3.25°), -3.70±4.91° (18.27±3.07°) respectively; the positive Collum angles indicated the lingually bent root relative to crown, while the negative indicated the labially bent root. The labial surface angles in upper and lower canine were significantly larger than that of intra-arch central and lateral incisors ( P<0.001). On the contrary, no significant differences were detected between central and lateral incisors in the maxilla and mandible ( P>0.05, P>0.05). Moreover, except for the maxillary central incisor, the Collum angle and labial surface angle were positively correlated. Conclusions:The values of Collum angle among anterior teeth are significantly different, and the obvious lingual-bent root are more likely accompanied with the greater labial surface curve, which might cause variable torqueing and be necessary to elevate before treatment.