Private Practice, Bad Essen, Germany.
Private Practice, Svendborg, Denmark.
Head Face Med. 2024 Oct 11;20(1):57. doi: 10.1186/s13005-024-00459-5.
The aim of the investigation was to evaluate if the inclination of the lower anterior teeth can be controlled reliably after lower premolar extraction for Class III camouflage treatment with completely customized lingual appliances (CCLAs). Treatment outcome was tested against the null hypothesis that lower premolar extractions for non-surgical camouflage treatment of a Class III malocclusion will lead to further compensation by retroclining mandibular incisors during CCLA treatment.
This retrospective study included 25 patients (f/m 12/13; mean age 20.7 years, SD 9.5 years) with uni- or bilateral Class III molar relationship and a Wits value of ≤ -2 mm. In all consecutively debonded patients, lower premolars were extracted to correct the sagittal relationship with a non-surgical camouflage approach. Lateral head films prior to (T1) and at the end of lingual orthodontic treatment (T2) were used to evaluate skeletal and dentoalveolar effects. A paired t-test with alpha = 5% was used to define differences between the endpoints. The linear correlation between the inclination of the mandibular incisors at T1 and the achieved correction was measured with the Pearson correlation coefficient (PCC). A Schuirmann's TOST equivalence test was used to check if the final lower incisor inclination was within the defined norms.
The null hypothesis was rejected as the mean lower incisor inclination was improved by 1.8° despite lower premolar extractions (T1: 86.8°/ T2: 88.6°). There was a strong correlation (-0.75) between the lower incisor inclination at T1 and the achieved correction indicating a controlled correction towards the norm regardless of the initial incisor position. At T2, the interincisal angle as well as the lower incisor inclination were within the norm.
Lower premolar extractions for non-surgical camouflage treatment of a Class III malocclusion will not lead to undesired retroclining of mandibular incisors during CCLA treatment even in severe cases.
本研究旨在评估对于 III 类错颌的掩饰性治疗，在下前磨牙拔除后，使用完全定制舌侧矫治器（CCLA）能否可靠地控制下切牙的倾斜度。该治疗结果通过以下零假设进行检验：对于 III 类错颌的非手术掩饰性治疗，下前磨牙拔除后，在 CCLA 治疗过程中，下颌切牙会进一步后倾代偿。
本回顾性研究纳入了 25 名患者（男女比 12/13；平均年龄 20.7 岁，标准差 9.5 岁），均存在单侧或双侧 III 类磨牙关系和 Wits 值≤-2mm。所有连续拆除固定矫治器的患者均拔除下前磨牙，以非手术掩饰性方法矫正矢状关系。在治疗前（T1）和结束时（T2）拍摄侧位头颅片，以评估骨骼和牙颌的影响。采用双侧 t 检验（alpha=0.05）来定义终点之间的差异。采用 Pearson 相关系数（PCC）测量 T1 时下颌切牙倾斜度与获得的矫正效果之间的线性相关性。采用 Schuirmann 的 TOST 等效性检验来检查最终下颌切牙倾斜度是否在定义的范围内。
尽管下前磨牙拔除，但下切牙平均倾斜度改善了 1.8°（T1：86.8°/T2：88.6°），这表明零假设被拒绝。T1 时的下切牙倾斜度与获得的矫正效果之间存在很强的相关性（-0.75），这表明在矫正过程中，下切牙会朝着正常方向倾斜，而与初始切牙位置无关。T2 时，切牙间角和下切牙倾斜度均在正常范围内。
对于 III 类错颌的非手术掩饰性治疗，在下前磨牙拔除后，使用 CCLA 治疗时，下颌切牙不会发生不可控的后倾，即使是在严重的情况下。
