3种方法确定水平颌位关系的全口义齿咀嚼肌肌电活动及咀嚼效率分析

Evaluation of electromyogram activity and masticatory efficiency in edentulous individuals whose maxillomandibular horizontal relationship records were obtained with three different methods

目的通过肌电图及吸光光度法比较3种方法确定水平颌位关系的全口义齿的咬肌和颞肌前束的肌电活动以及义齿的咀嚼效率。方法对10例口颌系统基本正常的无牙颌患者在适宜的垂直距离条件下,同时制作由哥特式弓轨迹顶点、哥特式弓轨迹顶点前1 mm以及直接咬合法确定水平颌位关系的3副全口义齿,分别记作义齿A、B和C。用肌电诱发电位仪分别记录患者戴用3副义齿在正中大力咬合及咀嚼过程中的咬肌和颞肌前束肌电图,记录肌电幅值,计算左右两侧咬肌和颞肌前束的不对称指数;用吸光光度法评价3副义齿的咀嚼效率;通过SPSS 17.0软件对所得数据进行统计学分析。结果在正中大力咬合及咀嚼运动过程中,义齿B和义齿C的肌电幅值明显高于义齿A(P<0.05),义齿C的不对称指数最高,明显高于义齿A和B(P<0.05)。义齿B和C咀嚼效率的差异无统计学意义(P>0.05),均高于义齿A(P<0.05)。结论在哥特式弓轨迹顶点前1 mm处建立水平颌位关系的全口义齿的肌电活动更强且更加平衡,有利于咀嚼肌功能的发挥,咀嚼效率较高。

Objective This study was performed to investigate the electromyographic （EMG） activity of the masseter muscle and the anterior temporalis muscle, as well as the masticatory efficiency after insertion of the dentures in edentulous individuals whose maxillomandibular horizontal relationship records were obtained with three different methods. Methods Ten edentulous individuals were enrolled in this study. Three types of complete dentures for these 10 edentulous patients were made according to their different maxillomandibular horizontal relationship records. The maxillomandibular horizontal relationship of complete dentures was recorded by three methods. In the first method （A）, the maxillomandibular horizontal relationship was determined at the gothic arch tracing apex. In the second method （B）, the relationship was 1 mm anterior to the tracing apex with the gothic arch. In the last method （C）, the horizontal jaw relation was recorded by natural chewing. The muscular activities of the three complete dentures were examined by EMG. The masticatory efficiency was evaluated based on the absorbance. The differences among the dentures were statistically analyzed with SPSS 17.0. Results The muscular activities of dentures B and C were much higher than that of denture A during clenching in the center occlusion and during chewing （P〈0.05）. The highest asymmetry index was found indenture C, which was significantly higher than those of dentures A and B （P〈0.05）. A statistically significant increase in the absorbance was observed between dentures B and C （P〈0.05）; otherwise, no statistically significant differences were observed （P〉0.05） between B and C. Conclusion Given the limitations of this experimental design, in edentulous individuals the maxillomandibular horizontal relationship recorded at 1 mm anterior to the tracing apex with the gothic arch can improve the function of masticatory muscles and strengthen masticatory performance.