Yau Hong-Tzong, Liao Shu-Wei, Chang Chia-Hao
National Chung Cheng University, Department of Mechanical Engineering, Chiayi, Taiwan; School of Dentistry, Kaohsiung Medical University, Kaohsiung, Taiwan.
National Chung Cheng University, Department of Mechanical Engineering, Chiayi, Taiwan.
Comput Methods Programs Biomed. 2020 Nov;196:105646. doi: 10.1016/j.cmpb.2020.105646. Epub 2020 Jul 9.
Temporomandibular joint has been considered one of the most complex joints in human body. Dental articulation hinged upon temporomandibular joint is essential and fundamentally important for dental restoration design and prosthetic/orthodontic occlusion analysis. As digital dentistry rapidly grows, a complete digital work flow requires the use of a digital articulator for occlusion analysis. However, commercial CAD/CAM systems do not provide any method to verify the modeling accuracy of a digital articulator. There is also a lack of detail and generalized mathematical modeling of the digital articulator for simulating the jaw movement.
This paper presents the development of a digital articulator by mathematically modeling a general dental articulator which simulates the relative jaw motion between the maxilla and mandible. As the digital articulator moves, the digital upper teeth move relatively to the digital lower teeth, thus simulating the occlusal path with teeth collision detection function. To verify the accuracy of our modeled digital articulator, an improved optical tracking method is proposed to measure the pose of a mechanical articulator with 6 degrees of freedom and compare that with the digital articulator.
The digital articulator system proposed in this paper achieves the following functions: 1. Digitalize the dental articulator with verified precision. Combined with dental design software, restorations can be designed with more efficiency and accuracy. 2. Provide an improved optical tracking method which can compare the movement error between the mechanical articulator and digital articulator. Thus the accuracy of the digital articulation can be verified. The result shows the error of our system is controlled under sub-millimeter which provides sufficient accuracy for the design of restoration under static and dynamic occlusion conditions.
We develop a general digital articulator which can simulate jaw movement between opposing teeth and an improved optical tracking method to verify the accuracy of the digital articulator. The modeling and accuracy verification of the digital articulator shows that there is a systematic and reliable way to replace traditional mechanical articulator and can close the gap for digital restoration fabrication.
颞下颌关节被认为是人体最复杂的关节之一。基于颞下颌关节的牙合关系对于牙齿修复设计以及修复/正畸咬合分析至关重要且具有根本意义。随着数字牙科的迅速发展，完整的数字工作流程需要使用数字牙合架进行咬合分析。然而，商业计算机辅助设计/计算机辅助制造（CAD/CAM）系统并未提供任何方法来验证数字牙合架的建模精度。同时，也缺乏用于模拟颌骨运动的数字牙合架的详细且通用的数学模型。
本文通过对通用牙合架进行数学建模来开发数字牙合架，该模型模拟上颌骨和下颌骨之间的相对颌骨运动。随着数字牙合架的移动，数字上牙相对于数字下牙相对移动，从而通过牙齿碰撞检测功能模拟咬合路径。为了验证我们建模的数字牙合架的准确性，提出了一种改进的光学跟踪方法来测量具有六个自由度的机械牙合架的位姿，并将其与数字牙合架进行比较。
本文提出的数字牙合架系统实现了以下功能：1. 以经过验证的精度将牙合架数字化。与牙科设计软件相结合，可以更高效、准确地设计修复体。2. 提供一种改进的光学跟踪方法，该方法可以比较机械牙合架和数字牙合架之间的运动误差。从而可以验证数字咬合的准确性。结果表明，我们系统的误差控制在亚毫米范围内，这为静态和动态咬合条件下的修复设计提供了足够的精度。
我们开发了一种通用的数字牙合架，可模拟相对牙齿之间的颌骨运动，并提出了一种改进的光学跟踪方法来验证数字牙合架的准确性。数字牙合架的建模和准确性验证表明，存在一种系统且可靠的方法来替代传统机械牙合架，并可以弥合数字修复制造的差距。
