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

本研究旨在探讨功能性下颌前突患者在矫治过程中，不同的促动器结构咬合高度对咀嚼肌活动的影响。它们被两种不同类型的活化剂处理。一种是采用高结构咬合（HBA），约10 mm，如伍德赛德型，另一种是低结构咬合（LBA），约2 mm。分别于治疗前、矫治后1个月和5个月记录患者最大咬牙强度、咀嚼口香糖和叩击牙齿运动的肌电变化。结果表明，在反牙合矫治后，HBA病例在磨牙区实现咬合接触和稳定咬合所需的时间比LBA病例短。在稳定期，在LBA病例中暂时观察到一些不稳定的闭塞。最大紧咬时HBA患者咀嚼肌肌电积分值无降低，而LBA患者咀嚼肌肌电积分值有所降低，且HBA患者咀嚼肌肌电静默期延长的趋势小于LBA患者。还研究了在夜间睡眠期间在适当位置具有激活剂的咀嚼肌活动。分别在夜间睡眠时佩戴HBA型和LBA型牙垫，记录咀嚼肌肌电。在分析的结果中，没有观察到积分EMG值与咬合高度的量的明显差异。

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.