Comparison in mandibular movement between subjects with deep bite and normal occlusion

• Main Authors: Pao-Chieh Lee, 李寶傑
• Other Authors: 余建宏
• Format: Others
• Language: zh-TW
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/4xsk8p

碩士 === 中國醫藥大學 === 牙醫學系碩士班 === 102 === Introduction and Objective Generally, we often evaluate the success of orthodontic treatment by dentition pattern and static images, however, we didn''t objectively evaluate if the oral function has been enhanced or not. A long existing question is that, is it relevant when patients’ appearance gets improved, the masticatory function of jaw also improves correspondingly? We have been long taking this question into account. Therefore we planned to compare jaw movement of two types of dentition pattern and to observe how differently the results display. Clinically, we often think of deep bite as a pathologic occlusion and its function should be worse than normal occlusion''s. Due to the limitation of deep bite subjects'' oral anatomy, in the past, there were few researches of deep bite subjects'' jaw movement using incisors as landmarks. Therefore the purpose of this study is to compare the mastication and border movements of jaw between subjects with deep bite and normal occlusion objectively. Expecting to figure out the myths and differences of jaw movement between deep bite and normal subjects, we hope to help deep bite patients get better quality of life after a period of orthodontic treatment. Materials and Methods Twenty-seven subjects were chosen from the students and staffs at the School of Dentistry and Hospital, China Medical University in Taiwan respectively. There were two study groups, one was normal occlusion containing 11 individuals, and the other was deep bite group containing 16 individuals. When they perform mastication and border movements of the jaw, their movements were recorded by using the clinical digital camera, and then we used DigiGnatho V1.3(Rise Corporation, SENDAI, JAPAN) to collect and analyze those movements. Results There were no much significant differences in mastication of right side or left side between the two groups, but we can still find out that the range and speed of mastication in deep bite group was lower than the control group. From the results of masticatory pattern we can also see that the pattern of deep bite group was different from that of the control group when lower jaw got approaching final occlusal phase. In the aspect of border movements, the values in the deep bite group were all much lower than those of control group, especially in the movement of jaw protrusion. Conclusion The mastication movement of normal occlusion subjects is tend to be better than that of the deep bite group, meanwhile, as if the deep bite subjects produced less grinding movement. It was obvious that the movement of jaw protrusion was affected by overbite itself much more prominently, and the relationship of upper and lower incisors would also influence the expression of jaw movements.