Inclination of Mandibular Incisors and Symphysis in Severe Skeletal Class III Malocclusion

Overview

Journal Head Face Med

Publisher Biomed Central

Specialties Dentistry
General Medicine
Orthopedics

Date 2023 May 10

PMID 37165461

Authors

Jieni Zhang

Yuqi Liang

Rui Chen

Si Chen

Jiuxiang Lin

Bing Han

Xiaomo Liu

Affiliations

Soon will be listed here.

Abstract

Objective: The aim of this study was to systematically explore the inclination of the lower central incisor and symphysis in alveolar bone in severe skeletal class III patients.

Materials And Methods: A total of 198 severe skeletal class III patients (ANB ≤ -4°) who underwent combined orthodontic and orthognathic treatment were divided into three groups based on the mandibular plane angle (MP-SN). Pretreatment lateral cephalograms were analysed and compared among the three groups. We also assessed cone-beam computed tomography (CBCT) images of 11 samples to investigate the reliability of the cephalometric analysis.

Results: ANOVA showed no statistically significant differences in the angle between the long axis of the mandibular symphysis and the long axis of the lower central incisor (MIA) among the low-angle, normal-angle and high-angle groups (P > 0.05), while significant differences were found in the angle between the axis of the lower incisor and the mandibular plane (IMPA) among the three groups (P < 0.001). The mean IMPA decreased with increasing MP-SN in the 198 patients. The mean MIA in the low-angle and normal-angle groups was 3.70° and 3.52°, respectively, while the value (2.33°) was smaller in the high-angle group. Paired-samples t test showed no statistically significant differences between the cephalometric and CBCT measurements of the MP-SN, the angle between the mandibular plane and the Frankfort plane (FH-MP) and the MIA (P > 0.05).

Conclusions: In severe skeletal class III patients, the long axis of the lower central incisor was highly consistent with the long axis of the mandibular symphysis, which was more obvious in the high-angle subjects. The MIA reflects the physiological inclination of the lower central incisor better than the IMPA.

Citing Articles

Lower incisor position in skeletal Class III malocclusion patients: a comparative study of orthodontic camouflage and orthognathic surgery.

Liu H, Zhang Y, Lu W, Yang Y, Liu X, Chen S Angle Orthod. 2024; 94(5):504-511.

PMID: 39230016 PMC: 11363981. DOI: 10.2319/122523-856.1.

Radiographic Imaging for the Diagnosis and Treatment of Patients with Skeletal Class III Malocclusion.

Li Z, Hung K, Ai Q, Gu M, Su Y, Shan Z Diagnostics (Basel). 2024; 14(5).

PMID: 38473016 PMC: 10931164. DOI: 10.3390/diagnostics14050544.

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