The Mmaticatory Muscles Activity Changes with Different Bite Height Activators During Dry and Night

本研究旨在探讨激活器的构造咬合高度的不同对功能性下颌骨突出症患者治疗过程中咀嚼肌活动的影响。它们被两种不同类型的活化剂处理。一种活化剂采用高结构咬合（HBA），约有10mm的内切距离，如Woodside型活化剂，另一种类型采用低结构咬合（LBA），约有2mm的内切距离。分别在治疗开始、矫正前交叉咬合1个月、5个月后，记录患者最大咬合、牙龈咀嚼、轻叩牙齿运动的肌电图记录。结果表明，与LBA患者相比，HBA患者在矫治后实现磨牙区咬合接触和稳定咬合所需的时间更短。在稳定期，LBA患者出现暂时性不稳定闭塞。这一发现得到了以下事实的支持：HBA组咀嚼肌在最大咬合时的综合肌电图值没有减少，而LBA组有一些减少，HBA组咀嚼肌肌电图沉默期的持续时间比LBA组有更少的延长趋势。在夜间睡眠的咀嚼肌活动与激活器的位置也进行了调查。单独正常咬合的成人在夜间睡眠时佩戴HBA样咬合块和LBA样咬合块，分别记录咀嚼肌肌电图。在分析结果中，综合肌电图值与咬高的大小没有明显的差异。

This study was conducted to investigate how the difference of the construction bite height of the activator would make effects on the masticatory muscles activity of functional mandibular protrusion patients during their treatment. They were treated by two different types of activators. One type of the activators employed high construction bite (HBA) which had about 10mm interincisal distance, such as Woodside type activator, and the other type employed low construction bite (LBA) which had about 2mm interincisal distance. The EMG records of the maximum clenching, the gum chewing and the tooth tapping movement were taken at the beginning of the treatment, one month after and five months after the correction of the anterior crossbite. As the results, after the crossbite correction, HBA cases took less time to achieve occlusal contacts in molar area and to stabilize the occlusion than LBA cases. During stabilizing phase, some unstable occlusions were temporarily observed at LBA cases. This finding was supported by the facts that the integrated EMG values of the masticatory muscles of HBA cases during the maximum clenching showed no reduction while some reductions were seen of LBA cases, and the duration of the silent period of the masticatory muscles EMG of HBA cases showed less prolonged tendency than of LBA cases. The masticatory muscles activity with an activator in place during night time sleep was also investigated. HBA like bite block and LBA like bite block were worn by the adults who had the individual normal occlusion during night time sleep and the EMG records of masticatory muscles were taken respectively. In the result of the analysis, no clear differences of the integrated EMG values with the amount of the bite height were observed.