Shimazaki Aya, Kimura Hitoshi, Inou Norio, Maki Koutaro
Department of Orthodontics, School of Dentistry, Showa University, Tokyo, Japan.
Department of Mechanical Engineering, School of Engineering, Tokyo Institute of Technology, Tokyo, Japan.
J Biomech. 2017 Oct 3;63:197-202. doi: 10.1016/j.jbiomech.2017.08.022. Epub 2017 Aug 24.
Devices called functional appliances are commonly used in orthodontics for treating maxillary protrusion. These devices mechanically force the mandible forward to apply traction force to the mandibular condyle. This promotes cartilaginous growth in the small mandible. However, no studies have clarified how much traction force is applied to the mandibular condyle. Moreover, it remains unknown as to how anatomical characteristics affect this traction force. Therefore, in this study, we developed a device for measuring the amount of force generated while individual patients wore functional appliances, and we investigated the relationship between forces with structures surrounding the mandibular condyle. We compared traction force values with cone-beam computed tomography image data in eight subjects. The functional appliance resulted in a traction force of 339-1477gf/mm, with a mean value of 196.5gf/mm for the elastic modulus of the mandible. A comparison with cone-beam computed tomography image data suggested that the mandibular traction force was affected by the mandibular condyle and shape of the articular eminence. This method can contribute to discovering efficient treatment techniques more suited to individual patients.
一种称为功能性矫治器的装置在正畸治疗上颌前突时常用。这些装置通过机械方式迫使下颌骨向前，从而对下颌髁突施加牵引力。这促进了小下颌骨的软骨生长。然而，尚无研究阐明施加在下颌髁突上的牵引力有多大。此外，解剖学特征如何影响这种牵引力仍不清楚。因此，在本研究中，我们开发了一种用于测量个体患者佩戴功能性矫治器时产生的力大小的装置，并研究了这些力与下颌髁突周围结构之间的关系。我们在八名受试者中比较了牵引力值与锥形束计算机断层扫描图像数据。功能性矫治器产生的牵引力为339 - 1477gf/mm，下颌骨弹性模量的平均值为196.5gf/mm。与锥形束计算机断层扫描图像数据的比较表明，下颌牵引力受下颌髁突和关节结节形状的影响。这种方法有助于发现更适合个体患者的有效治疗技术。
