Xiong Jing, Zhang Ying, Liu Lei
Department of Stomatology, Hanzhong Central Hospital Hanzhong 723000, Shaanxi, China.
Medical Record Statistics Section, Hanzhong Central Hospital Hanzhong 723000, Shaanxi, China.
Am J Transl Res. 2025 Aug 15;17(8):6275-6290. doi: 10.62347/YGFV7405. eCollection 2025.
To investigate the effects of different stress application methods of invisible aligners on anterior tooth retraction using three-dimensional finite element analysis.
An adult patient with maxillary protrusion undergoing orthodontic treatment with the extraction of the first premolars was selected for modeling. Five working conditions were simulated: ① Invisible aligner applying force for overall retraction of the maxillary anterior teeth; ② Invisible aligner combined with a micro - implant placed at the canine region's precise cutting site, applying a 1N force for overall anterior retraction; ③ Same as condition 2, with an additional 1 N force applied between the anchorage micro-implant near the maxillary central incisors and the aligner; ④ Invisible aligner applying a 1 N force at the canine region's precise cutting site for overall retraction; ⑤ Invisible aligner applying force combined with power ridge technology for root - controlled retraction of anterior teeth. Displacement and stress measurements-including displacement and stress at the coronal-radicular junction and periodontal ligament, as well as their components along the X (mesiodistal), Y (labiolingual), and Z (vertical) axes under different working conditions-were compared.
Total tooth displacements were similar across all conditions (range: 0.23197-0.23276 mm), with conditions ③ and ⑤ showing slightly lower displacement, though differences were not statistically significant. Stress at the coronal-radicular junction varied between 63.298-63.964 MPa, with conditions ② and ④ exhibiting slightly higher values. Condition ⑤ demonstrated a slight reduction in junction stress (63.703 MPa), attributed to root - control technology. Periodontal ligament stress showed a gradual increase from 0.41426 MPa (condition ①) to 0.41634 MPa (condition ⑤), representing a minimal overall change. Displacement was predominantly along the Y axis (approximately 0.205-0.206 mm), with smaller movements in the X (0.055-0.056 mm) and Z (0.095-0.096 mm) directions.
All 5 working conditions produced comparable displacement outcomes, with condition ⑤ offering an advantage in reducing stress at the coronal-radicular junction, suggesting a benefit of root-controlled retraction in clinical application.
采用三维有限元分析方法，研究隐形矫治器不同加力方式对上颌前牙内收的影响。
选取1例拔除第一前磨牙进行正畸治疗的成人上颌前突患者进行建模。模拟5种工况：①隐形矫治器整体加力内收上颌前牙；②隐形矫治器联合微种植体置于尖牙区精确切割位点，施加1N力整体前牙内收；③同工况2，在上颌中切牙附近的支抗微种植体与矫治器之间额外施加1N力；④隐形矫治器在尖牙区精确切割位点施加1N力整体内收；⑤隐形矫治器加力联合动力嵴技术进行前牙根控内收。比较不同工况下包括牙冠-牙根交界处和牙周膜的位移和应力，以及它们沿X（近远中）、Y（唇舌）和Z（垂直）轴的分量。
所有工况下的总牙位移相似（范围：0.23197 - 0.23276mm），工况③和⑤的位移略低，尽管差异无统计学意义。牙冠-牙根交界处的应力在63.298 - 63.964MPa之间变化，工况②和④的值略高。工况⑤的交界处应力略有降低（63.703MPa），归因于根控技术。牙周膜应力从工况①的0.41426MPa逐渐增加到工况⑤的0.41634MPa，总体变化极小。位移主要沿Y轴（约0.205 - 0.206mm），在X轴（0.055 - 0.056mm）和Z轴（0.095 - 0.096mm）方向的移动较小。
所有5种工况产生的位移结果相当，工况⑤在降低牙冠-牙根交界处应力方面具有优势，表明根控内收在临床应用中有益处。
