Study on the effect of chin morphology on orthodontic treatment.
10.7518/hxkq.2023.2022508
- Author:
Yu FU
1
;
Ziwei LI
1
;
Menghan ZHAO
1
;
Ruixin SHI
1
Author Information
1. Dept. of Orthodontics, Hospital of Stomatology, Jilin University, Changchun 130021, China.
- Publication Type:Journal Article
- Keywords:
Angle classⅠ;
chin morphology;
soft tissue profile
- MeSH:
Adult;
Humans;
Female;
Chin;
Lip;
Cephalometry/methods*;
Esthetics, Dental;
Mandible
- From:
West China Journal of Stomatology
2023;41(4):443-449
- CountryChina
- Language:English
-
Abstract:
OBJECTIVES:To investigate the effect of different soft-tissue morphologies on the treatment of skeletal class Ⅰ malocclusion patients by analyzing measurement data before and after treatment.
METHODS:Pre- and post-treatment lateral cephalograms of 55 adult female Angle class Ⅰ patients were collected in the Department of Orthodontics, Hospital of Stomatology, Jilin University from January 2012 to December 2020. Chin soft-tissue morphologies in the lateral cranial radiographs were used to divide the patients into an abnormal chin morphology group (flat and retracted chins, n=27) and a normal chin morphology group (rounded and prominent chins, n=28). Relevant soft- and hard-tissue indexes were selected to study in-group varieties and intergroup differences in the varying chin morphologies before and after treatment.
RESULTS:The chin-lip angle, mandibular chin angle, mandibular chin vertex angle, PP-MP, LL-E, UL-E, Po-Pos, and B-B' thickness in the abnormal chin morphology group were significantly higher than those in the normal chin morphology group (P<0.05). Furthermore, m∶BMe and n∶B'Mes in the abnormal chin morphology group were signi-ficantly lower than those in the normal chin morphology group (P<0.05). After treatment, the mandibular chin angle, mandibular chin vertex angle, U1-SN, L1-MP, LL-E, UL-E, SNA, SNB, and B-B' thickness of the abnormal chin morphology group significantly decreased (P<0.05), whereas the nasolabial angle, m∶BMe, n∶B' Mes, and Po-Pos significantly increased (P<0.05). In the normal chin morphology group, the U1-SN, L1-MP, LL-E, UL-E, and B-B' thicknesses decreased significantly (P<0.05), whereas the nasolabial angle significantly increased (P<0.05). Among them, m∶BMe and n∶B' Mes were positively correlated.
CONCLUSIONS:Chin morphology affects the formulation of treatment plans. Compared with the normal chin morphology group, the abnormal chin morphology group required a larger retraction of incisors. Although the chin of soft-tissue morphology is related to the morphology of bones, the changes in soft tissue chin after treatment cannot be directly predicted according to the bone changes. Soft-tissue chin morphology affects the aesthetic assessment of the soft-tissue lateral profile and the change in soft tissue before and after treatment. The method of predicting the change in soft-tissue chin after treatment should consider the morphology of the soft-tissue chin.
