Janson Guilherme, Araki Janine, Estelita Sérgio, Camardella Leonardo T
Department of Orthodontics, Bauru Dental School, University of São Paulo, Alameda Octávio Pinheiro Brisolla 9-75, Bauru 17012-901, São Paulo , Brazil.
Prog Orthod. 2014 Dec 30;15(1):67. doi: 10.1186/s40510-014-0067-4.
The purpose of this study was to compare the occlusal stability of class II subdivision malocclusion treatment with 3 and 4 first premolar extractions. A sample of 156 dental casts from 52 patients with class II subdivision malocclusion was divided into two groups according to the extraction protocol. Group 1 comprised 24 patients treated with 3 premolar extractions and group 2 included 28 patients treated with 4 premolar extractions.
Peer assessment rating (PAR) indexes were measured on the dental casts obtained before (T1) and after treatment (T2) and at a mean of 6.9 years after the end of treatment (T3). The groups were matching regarding sex distribution, pretreatment, posttreatment and long-term posttreatment ages, and treatment and long-term posttreatment times. They were also comparable concerning the initial malocclusion severity and the occlusal results at the end of treatment. Stability evaluation was calculated by subtracting the posttreatment from the long-term posttreatment index values (T3 - T2). T tests were used to compare the amount and percentage of long-term posttreatment changes.
There were no intergroup differences regarding the amount and percentage of long-term posttreatment changes.
Treatment of class II subdivision malocclusion with 3 and 4 premolar extractions have a similar long-term posttreatment occlusal stability.
本研究的目的是比较拔除3颗和4颗第一前磨牙治疗安氏II类亚类错牙合的咬合稳定性。从52例安氏II类亚类错牙合患者中选取156个牙模样本，根据拔牙方案分为两组。第1组包括24例接受3颗前磨牙拔除治疗的患者，第2组包括28例接受4颗前磨牙拔除治疗的患者。
在治疗前（T1）、治疗后（T2）以及治疗结束后平均6.9年（T3）获取的牙模上测量同侪评估等级（PAR）指数。两组在性别分布、治疗前、治疗后及治疗后长期的年龄，以及治疗和治疗后长期的时间方面相匹配。在初始错牙合严重程度和治疗结束时的咬合结果方面也具有可比性。通过用治疗后长期指数值减去治疗后指数值（T3 - T2）来计算稳定性评估。采用t检验比较治疗后长期变化的量和百分比。
治疗后长期变化的量和百分比在组间无差异。
拔除3颗和4颗前磨牙治疗安氏II类亚类错牙合具有相似的治疗后长期咬合稳定性。
