Miao Yaoqiang, Liu Conghua
Department of Orthodontics, Guangdong Provincial Stomatological Hospital, Guangzhou 510260, China.
Zhonghua Kou Qiang Yi Xue Za Zhi. 2002 May;37(3):216-8.
To investigate the correlative factors influencing the stability of orthodontic treatment out of retention.
Pre-treatment, post-treatment and 2 approximately 8 years out of retention study models of 74 cases with malocclusion were assessed by the PAR (Peer Assessment Rating) index.
(1) Out of retention, the relapse rate was 13.01% in weighted PAR total scores and the relapse rate was 6.38%, 15.56%, 28.86%, 22.41% in alignment, overjet, overbite and transverse buccal occlusion respectively. (2) The rate of great improvement was decreased from 77.03% after treatment to 64.86% out of retention. The PAR score increased in 53 cases (71.62%), unchanged in 6 cases (8.11%) and reduced in 15 cases (20.27%) out of retention. (3) The weighted total scores in the Begg appliance were higher than that in Edgewise out of retention (P < 0.05). (4) The alignment and PAR total scores out of retention were higher in class II malocclusion than in class I malocclusion (P < 0.05). (5) The weighted PAR total scores post-retention were higher in unilateral extraction than in other groups (P < 0.01).
(1) There was a trend that teeth relapsed to original position out of retention. The relapse rate was greater in alignment, overjet, overbite and transverse buccal occlusion. (2) The stability out of retention was not related to patient's age and sex, but was related to the types of appliance, malocclusion and extraction.
探讨影响正畸治疗保持期后稳定性的相关因素。
采用PAR（同行评估等级）指数对74例错牙合畸形患者治疗前、治疗后及保持约8年的研究模型进行评估。
（1）保持期后，加权PAR总分的复发率为13.01%，牙列排齐、覆盖、覆牙合及颊侧横向牙合的复发率分别为6.38%、15.56%、28.86%、22.41%。（2）显著改善率从治疗后的77.03%降至保持期后的64.86%。保持期后，53例（71.62%）PAR评分增加，6例（8.11%）不变，15例（20.27%）降低。（3）保持期后，Begg矫治器的加权总分高于方丝弓矫治器（P<0.05）。（4）安氏II类错牙合畸形保持期后的牙列排齐和PAR总分高于安氏I类错牙合畸形（P<0.05）。（5）单侧拔牙组保持期后的加权PAR总分高于其他组（P<0.01）。
（1）保持期后牙齿有恢复到原始位置的趋势。牙列排齐、覆盖、覆牙合及颊侧横向牙合的复发率更高。（2）保持期后的稳定性与患者年龄和性别无关，但与矫治器类型、错牙合畸形及拔牙有关。
