State Key Laboratory of Oral & Maxillofacial Reconstruction and Regeneration, National Clinical Research Center for Oral Diseases, Shaanxi Clinical Research Center for Oral Diseases, Department of Orthodontics, School of Stomatology, Air Force Medical University, Xi'an, China.
BMC Oral Health. 2024 Jan 20;24(1):115. doi: 10.1186/s12903-024-03867-w.
To investigate the effect of sequential distalization on increasing gaps in the maxillary anterior teeth, focusing on the control of torque and three-dimensional teeth movement during anterior retraction with clear aligners in extraction cases.
We recruited 24 patients who were undergoing extraction bilateral maxillary first premolars with clear aligners. According to a predetermined increment in the spaces between the maxillary anterior teeth, the patients were divided into three groups: those with no gap (9 cases), a 0.5 mm gap (6 cases) and a 1.0 mm gap (9 cases). In each group, a 2.0 mm en-mass retraction was applied on the anterior teeth. Plaster casts of the upper full dentition were obtained both before and after a 2 mm retraction. The palatal folds were used to overlap each pair of models. The three-dimensional movement of the teeth and the change of torque for the anterior teeth were subsequently analyzed using Geomagic Studio 2014 software.
The change in torque in the groups with added gaps was significantly smaller than that in the group with no gaps (P < 0.05). There was no significant difference in this respect when comparing the group with a 0.5 mm gap added to the group with a 1.0 mm gap was added (P > 0.05). In the labial-lingual and vertical directions, the displacements of the central and lateral incisors were smaller in the groups with additional gaps compared to those in the groups without gaps (P < 0.05). However, there was no significant difference observed when comparing the group with a 0.5 mm added gap to the group with a 1.0 mm added gap (P > 0.05). Then, a comparison was made between the displacement of the second premolar to the second molar in the mesial-distal direction across all groups. The study revealed that the anchorage molars in the group without gaps demonstrated significantly smaller displacement compared to those in the group with additional gaps (P < 0.05).
Advantages were observed in controlling the torque of the anterior teeth and achieving a desired pattern closer to normal bodily movement by sequentially distalizing the maxillary anterior teeth gaps. Increasing the gaps between the maxillary anterior teeth also resulted in improved control of the vertical direction of the anterior teeth. However, this retraction strategy necessitates substantial protection of the anchorage molars.
探讨在使用透明牙套进行上颌前牙整体内收时，通过序列远移增加上颌前牙间隙，控制转矩和牙齿三维移动的效果。
我们招募了 24 名使用透明牙套进行上颌双侧第一前磨牙拔牙的患者。根据上颌前牙间隙的预定增量，患者被分为三组：无间隙组（9 例）、0.5mm 间隙组（6 例）和 1.0mm 间隙组（9 例）。每组在前牙上施加 2.0mm 的整体内收。在 2mm 内收后，获取上颌全牙列石膏模型。使用腭皱襞将每对模型重叠。随后使用 Geomagic Studio 2014 软件分析牙齿的三维运动和前牙转矩的变化。
增加间隙组的转矩变化明显小于无间隙组（P<0.05）。添加 0.5mm 间隙组与添加 1.0mm 间隙组之间在这方面没有显著差异（P>0.05）。在唇舌向和垂直向，与无间隙组相比，添加间隙组的中切牙和侧切牙的位移较小（P<0.05）。然而，添加 0.5mm 间隙组与添加 1.0mm 间隙组之间没有观察到显著差异（P>0.05）。然后，比较了所有组中近远中向第二前磨牙到第二磨牙的位移。结果表明，无间隙组的支抗磨牙的位移明显小于添加间隙组（P<0.05）。
通过序列远移上颌前牙间隙，可以控制前牙转矩，使牙齿移动模式更接近正常生理运动，从而获得优势。增加上颌前牙间隙也可以更好地控制前牙的垂直向。然而，这种内收策略需要对支抗磨牙进行充分保护。
