ElNaghy Rahma, Grossman Stephanie, Hasanin Majd, Al-Qawasmi Riyad
Associate Professor, Director of Craniofacial and Special Care Orthodontics Clinic, Graduate Orthodontics Division, University of Detroit Mercy School of Dentistry, Detroit, Michigan, USA.
Orthodontist, Private Practice, Vaughan, Ontario, Canada.
J World Fed Orthod. 2025 Apr;14(2):76-83. doi: 10.1016/j.ejwf.2024.09.009. Epub 2024 Oct 24.
This study used cone-beam computed tomography (CBCT) via voxel-based superimposition to evaluate lip and incisor changes after orthodontic treatment with four premolar extractions (Ext) versus nonextraction (Non-Ext) among African American (AA) and White (W) patients.
A total of 240 CBCTs of 120 adolescent orthodontic patients with Class I skeletal/dental relationships were included. Patients were initially divided according to treatment, and then each group was subdivided according to patients' ethnicity (Ext/W = 30, Ext/AA = 30, Non-Ext/W = 30, and Non-Ext/AA = 30). CBCTs were imported into Invivo6 for voxel-based superimposition. Lip and incisor measurements were recorded. Independent t tests and two-way ANOVA were used for statistical assessment.
The Non-Ext/W group had a greater increase in all outcome variables compared with the Non-Ext/AA group, with a significant change in volume and position of upper (UL) and lower lips (LL), inclination of upper (U1) and lower incisors (L1), and position of U1. The Ext/AA group had a greater decrease in all measured outcomes compared with the Ext/W group, with significant change in inclination of U1 and L1, and position and volume of LL. W patients had more crowding than AA patients in both treatment approaches. Retraction ratios of 6.5:1 and 2.1:1 were recorded between the U1 and UL positions, and L1 and LL positions, respectively. There were no direct interaction effects between ethnicity and treatment, nor were there any significant effects of ethnicity after controlling for the covariates.
Ethnicity alone has no impact on incisor and lip position after treatment. However, ethnicity in the form of initial presentation of malocclusion can have a significant influence.
本研究采用基于体素叠加的锥形束计算机断层扫描（CBCT），评估非裔美国（AA）和白人（W）患者在拔除四颗前磨牙（拔牙组）与不拔牙（非拔牙组）正畸治疗后唇部和切牙的变化。
纳入120例具有Ⅰ类骨骼/牙性关系的青少年正畸患者的240份CBCT。患者最初根据治疗方法分组，然后每组再根据患者种族细分（拔牙/W组 = 30例，拔牙/AA组 = 30例，非拔牙/W组 = 30例，非拔牙/AA组 = 30例）。将CBCT导入Invivo6进行基于体素的叠加。记录唇部和切牙的测量数据。采用独立t检验和双向方差分析进行统计学评估。
与非拔牙/AA组相比，非拔牙/W组所有结局变量的增加幅度更大，上唇（UL）和下唇（LL）的体积和位置、上切牙（U1）和下切牙（L1）的倾斜度以及U1的位置均有显著变化。与拔牙/W组相比，拔牙/AA组所有测量结局的减少幅度更大，U1和L1的倾斜度、LL的位置和体积均有显著变化。在两种治疗方法中，W患者比AA患者拥挤程度更高。U1与UL位置、L1与LL位置之间记录的内收比分别为6.5:1和2.1:1。种族与治疗之间没有直接的交互作用，在控制协变量后种族也没有任何显著影响。
单独种族因素对治疗后切牙和唇部位置没有影响。然而错牙合初始表现形式中的种族因素可能有显著影响。
