The crown-root morphology of central incisors in different skeletal malocclusions assessed with cone-beam computed tomography

Progress in Orthodontics

Hui Xue¹  Ling-zhi Ma²  Jing Wang³  Xiao-ming Wang⁴ 

[1] 0000 0000 9255 8984, grid.89957.3a, Department of Stomatology, The Affiliated Suzhou Hospital of Nanjing Medical University, 215000, Suzhou, Jiangsu Province, China;0000 0000 9588 0960, grid.285847.4, Department of Orthodontics, Stomatological Hospital of Kunming Medical University, 650032, Kunming, China;0000 0001 0599 1243, grid.43169.39, Department of Orthodontics, Xi’an JiaoTong University Hospital of Stomatology, 710004, Xi’an, Shaanxi Province, China;0000 0001 0807 1581, grid.13291.38, State Key Laboratory of Oral Diseases, Department of Cleft Lip and Palate Surgery, West China Hospital of Stomatology, Sichuan University, 610041, Chengdu, China;

关键词: Crown-root morphology;    Skeletal malocclusion;    Collum angle;    Labial surface angle;    Cone-beam CT;   

DOI  :  10.1186/s40510-019-0272-2

来源: publisher

【 摘 要 】

BackgroundTo determine the discrepancy of crown-root morphology of central incisors among different types of skeletal malocclusion using cone-beam computed tomography (CBCT) and to provide guidance for proper torque expression of anterior teeth and prevention of alveolar fenestration and dehiscence.MethodsIn this retrospective study, a total of 108 CBCT images were obtained (ranging from 18.0 to 30.0 years, mean age 25.8 years). Patients were grouped according to routine sagittal and vertical skeletal malocclusion classification criteria. The patients in sagittal groups were all average vertical patterns, with Class I comprised 24 patients—14 females and 10 males; Class II comprised 20 patients—13 females and 7 males; and Class III comprised 22 subjects—13 females and 9 males. The patients in vertical groups were all skeletal Class I malocclusions, with low angle comprised 21 patients—12 females and 9 males; average angle comprised 24 patients; and high angle comprised 21 patients—11 females and 10 males. All the CBCT data were imported into Invivo 5.4 software to obtain a middle labio-lingual section of right central incisors. Auto CAD 2007 software was applied to measure the crown-root angulation (Collum angle), and the angle formed by a tangent to the central of the labial surface of the crown and the long axis of the crown (labial surface angle). One-way analysis of variance (ANOVA) and Scheffe’s test were used for statistical comparisons at the P < 0.05 level, and the Pearson correlation analysis was applied to investigate the association between the two measurements.ResultsThe values of Collum angle and labial surface angle in maxillary incisor of Class II and mandibular incisor of Class III were significantly greater than other types of sagittal skeletal malocclusions (P < 0.05); no significant difference was detected among vertical skeletal malocclusions. Notably, there was also a significant positive correlation between the two measurements.ConclusionsThe maxillary incisor in patients with sagittal skeletal Class II malocclusion and mandibular incisor with Class III malocclusion present remarkable crown-root angulation and correspondingly considerable labial surface curvature. Equivalent deviation during bracket bonding may cause greater torque expression error and increase the risk of alveolar fenestration and dehiscence.

【 授权许可】

CC BY