Clinical Study of Mandibular Movement Pre and Post RPD Treatment among Subjects with Dentition Defects of KennedyⅠorⅡ

［Abstract］Objective To provide an objective reference to evaluate the efficacy of the RPD restoration. Methods According to the RPD restored history, patients were divided into 2 groups：groupⅠand groupⅡ．Patients in groupⅠhad never restored their missing teeth before．The SAM axioquick recorder was used to record mandibular motion track and rang pre and post RPD treatment. Simultaneously，we recorded the surficial myoelectricity of bilateral masseter and temporalis. At last，we measured one minute masticatory efficiency of each subject by light absorption method．Results（1）The range of chewing movement increased 6 months after RPD treatment，the incisal path showed a good regularity and repeatability in the frontal plane. The width of chewing ring increased from（0.73±0.34）mm to（2.58±1.01）mm（P＜0.05）in group Ⅰ. （2）During border movement，the motion track showed a better smoothness，repetitiveness than previous. The range of opening increased from（31.51±6.37）mm to（61.95±12.42）mm while protrusion increasing from（4.22±2.85）mm to 8.38±1.13mm（P＜0.05） among the subjects with restorative history. （3）All cases' abnormal EMG activity were relieved， while the coordination improving. （4）Two groups' chewing efficiency were improved obviously（P＜<0.05）. Conclusion Clinical application of mandibular trajectory and EMG of masticatory muscle can provide an objective reference to evaluate the efficacy of the RPD restoration.