The Aga Khan University Hospital, Department of Surgery, Section of Dentistry, P.O Box 3500, Stadium Road, 74800 Karachi, Pakistan.
The Aga Khan University Hospital, Department of Surgery, Section of Dentistry, P.O Box 3500, Stadium Road, 74800 Karachi, Pakistan.
Int Orthod. 2021 Dec;19(4):641-651. doi: 10.1016/j.ortho.2021.08.002. Epub 2021 Aug 24.
The aim of this retrospective study was to identify cephalometric predictors associated with favourable soft tissue profile outcomes after premolars extraction and non-extraction in class I malocclusion subjects.
A total of 80 subjects, treated with non-extraction and premolars extraction (40 subjects each), were equally divided into favourable (FG) and unfavourable (UFG) groups using subjective and objective soft tissue profile outcome assessment methods. An independent t-test was utilized for the comparison of cephalometric measurements between the non-extraction (NE) and premolars extraction (PME) treatment modalities. Cox proportional hazard algorithm regression analysis was performed to identify cephalometric factors associated with favourable soft tissue outcomes.
The pre-treatment mean age of the NE group was 20.2±2.3 and PME group was 20.2±2.5 years. After dividing the sample of the NE and PME groups according to subjective and objective soft-tissue outcome assessment criteria, FG and UFG consisted of 20 subjects each. Cox proportional hazard algorithm regression analysis found upper incisor to NA angle (95% CI: 1.033, 1.196) to be associated with FG in NE and upper incisor to SN (95% CI: 1.018, 1.206) and ANB angle (95% CI:1.165, 3.608) in PME. There was a statistically significant strong correlation between subjective and objective evaluation methods (P≤0.001).
Cephalometric analysis is a valuable tool to predict soft-tissue outcomes after NE and PME. Increased upper incisors inclinations at the start of NE treatment result in favourable soft tissue profile outcomes. Slightly convex profile and proclined maxillary incisors are the predictors of favourable soft tissue profile outcome after PME. There was a statistically significant association between subjective and objective evaluation criteria of soft tissue outcomes.
本回顾性研究旨在确定与 I 类错颌畸形患者拔牙和非拔牙后软组织侧貌改善相关的头影测量学预测因子。
本研究共纳入 80 名患者（40 名非拔牙患者和 40 名拔牙患者），分别采用主观和客观软组织侧貌评估方法将其分为改善组（FG）和非改善组（UFG）。采用独立 t 检验比较非拔牙（NE）和拔牙（PME）治疗组的头影测量值。采用 Cox 比例风险回归分析确定与软组织改善相关的头影测量学因素。
NE 组的治疗前平均年龄为 20.2±2.3 岁，PME 组为 20.2±2.5 岁。根据主观和客观软组织评估标准将 NE 和 PME 组的样本进行分组后，FG 和 UFG 组各包含 20 名患者。Cox 比例风险回归分析发现，NE 组中，上切牙与 NA 角（95%CI：1.033，1.196）相关，而在 PME 组中，上切牙与 SN（95%CI：1.018，1.206）和 ANB 角（95%CI：1.165，3.608）相关。主观和客观评估方法之间存在显著的强相关性（P≤0.001）。
头影测量分析是预测 NE 和 PME 后软组织侧貌结果的一种有价值的工具。NE 治疗开始时上切牙倾斜度增加可导致软组织侧貌改善。轻度凸面型和上颌切牙前倾是 PME 后软组织侧貌改善的预测因子。主观和客观软组织侧貌评估标准之间存在显著的统计学关联。
