Kinematic Analysis of Jaw Function in Young Adults in Taiwan
摘要
Background: Temporomandibular disorder (TMD) is a multifactorial disease diagnosed based on comprehensive history and clinical examination nowadays. Maximal mouth opening (MMO) has traditionally been used as an important parameter in evaluating the function of temporomandibular joint (TMJ) and masticatory muscle. However, there is still lack of an ideal method and standardized evaluation device for measurement of dynamic function of the TMJ and mandible. Aim and Objectives: The purpose of this study was to develop a clinically applicable, reliable, quantitative and noninvasive system to measure the kinematic TMJ function and jaw movement, in a dynamic and continuous way. Materials and Methods: The study group consisted of 30 young healthy adults, 18 male and 12 female. Zebris jaw motion analyzer (JMA) was used to evaluate their jaw functions, including maximum mouth opening capacity (MOC), condylar path length (CPL), and opening/closing ratio (OCR). Results: The MOC was 46.70 ± 11.8 mm in men and 46.70 ± 6.3 mm in female group (p = 0.783). For condylar range of motion, the mean CPL during mouth opening was 11.10±3.1 mm over right side and 11.80 ± 3.0 mm over left side (p = 0.076). There is no significant difference between bilateral condylar and incisal movement. The zebris JMA system showed different kinematic movement and duration of opening and closing phase in a TMJ motion cycle, with OCR about 6:4 in the study group. Conclusion: The zebris JMA system can evaluate jaw movement in a dynamic and continuous way, and it can offer the kinematic information and also has characteristics of biofeedback. In all, the JMA is a reliable, quantitative and noninvasive system to measure the TMJ function and jaw movement.