Department of Orthodontics, Peking University School and Hospital of Stomatology, Beijing, China.
Division of Paediatric Dentistry and Orthodontics, Faculty of Dentistry, the University of Hong Kong, Hong Kong SAR, China.
Eur J Orthod. 2024 Jan 1;46(1). doi: 10.1093/ejo/cjad077.
BACKGROUND/OBJECTIVES: To compare the biomechanical characteristics of maxillary molar distalization with clear aligners in conjunction with three types of miniscrew anchorage.
MATERIALS/METHODS: Three-dimensional (3D) finite element models of maxillary molar distalization with clear aligners and three types of miniscrew anchorage were established, including (A) control group, (B) direct buccal miniscrew anchorage group, (C) direct palatal miniscrew anchorage group, and (D) indirect buccal miniscrew anchorage group. The 3D displacement of maxillary teeth and the principal stress (maximum tensile and compressive stress) on the root and periodontal ligament (PDL) during molar distalization were recorded.
The tooth displacement pattern during maxillary molar distalization in the four groups showed similarities, including labial tipping of anterior teeth, mesial and buccal tipping of premolars, and distal and buccal tipping of molars, but with varying magnitudes. Group C exhibited the greatest molar distalization, with the first molar achieving 0.1334 mm of crown distalization. Group D demonstrated a notable buccal crown movement (0.0682 mm) and intrusion (0.0316 mm) of the first premolar. Compared to Groups A and B, Groups C and D showed less labial crown tipping of the central incisor. Group B showed the greatest amount of maxillary incisor intrusion (central incisor: 0.0145 mm, lateral incisor: 0.0094 mm). Moreover, Groups C and D displayed significantly lower levels of compressive and tensile stress in the roots and PDL of the maxillary central and lateral incisors.
Molar distalization is a dynamic process involving sequential tooth movement stages; however, our research primarily examined the tooth movement patterns in the initial aligner.
CONCLUSIONS/IMPLICATIONS: The use of miniscrew anchorage, especially direct palatal miniscrew anchorage, may enhance the treatment efficacy of maxillary molar distalization with clear aligners, leading to increased molar distalization, reduced mesial movement of premolars, and minimized labial tipping of anterior teeth.
背景/目的：比较使用隐形矫治器结合三种微型种植体支抗进行上颌磨牙远移的生物力学特征。
材料/方法：建立了使用隐形矫治器结合三种微型种植体支抗进行上颌磨牙远移的三维（3D）有限元模型，包括（A）对照组、（B）直接颊侧微型种植体支抗组、（C）直接腭侧微型种植体支抗组和（D）间接颊侧微型种植体支抗组。记录上颌牙齿的三维位移和磨牙远移过程中牙根和牙周膜（PDL）的主应力（最大拉伸和压缩应力）。
四组上颌磨牙远移过程中的牙齿位移模式相似，包括前牙唇倾、前磨牙近中及颊倾、磨牙远中及颊倾，但程度不同。组 C 表现出最大的磨牙远移，第一磨牙实现了 0.1334mm 的冠远移。组 D 显示出第一前磨牙明显的颊侧冠移动（0.0682mm）和内收（0.0316mm）。与组 A 和 B 相比，组 C 和 D 显示出中切牙唇侧冠的倾斜度较小。组 B 显示出上颌切牙最大的内倾量（中切牙：0.0145mm，侧切牙：0.0094mm）。此外，组 C 和 D 显示上颌中切牙和侧切牙的牙根和 PDL 中的压缩和拉伸应力明显降低。
磨牙远移是一个涉及连续牙齿移动阶段的动态过程；然而，我们的研究主要检查了初始矫治器中的牙齿移动模式。
结论/意义：微型种植体支抗的使用，特别是直接腭侧微型种植体支抗的使用，可能增强使用隐形矫治器进行上颌磨牙远移的治疗效果，导致磨牙远移增加、前磨牙近中移动减少和前牙唇倾度最小化。
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