Kossioni A E, Karkazis H C, Molivdas P A
Experimental EMG Laboratory, Department of Removable Prosthodontics, Dental School, University of Athens, Greece.
Gerodontology. 1995 Jul;12(1):31-6. doi: 10.1111/j.1741-2358.1995.tb00127.x.
The aim of the present study was to investigate any variations in the jaw-jerk reflex in edentulous subjects wearing complete dentures, compared to an age and sex-matched dentate group. The reflex was elicited by chin taps in 22 older dentate subjects with mean age 61.3 years and in 22 denture wearers with mean age 63.1 years. Surface electromyographic recordings were obtained from the masseter muscle of the preferred chewing side during mandibular rest and at moderate clenching (40% of the individual maximum clenching masseteric EMG activity). A jaw-jerk reflex was recorded in all subjects at least once, and its occurrence during clenching was reduced compared to rest. The occurrence of the reflex was however increased in the denture wearers in both experimental conditions, while minor differences were observed in the values for latency, duration and amplitude between the two dental status groups. These results suggest that under the present experimental conditions the periodontal ligament receptors might inhibit reflex activity. Multiple sensory interactions are expected in denture wearing. However a particular source of sensory feedback is provided by the stimulation of mucosal receptors from the acrylic denture base. Since the occurrence of the jaw-jerk at clench in the denture wearers was also reduced compared to the rest experiments, a potential inhibitory effect of the mucosal receptors can be speculated. According to the findings in the present study the loss of teeth and the rehabilitation with complete dentures do not severely disrupt the reflex activity investigated.
本研究的目的是调查与年龄和性别匹配的有牙列组相比，佩戴全口义齿的无牙颌受试者的下颌反射是否存在差异。通过轻叩22名平均年龄61.3岁的老年有牙列受试者和22名平均年龄63.1岁的义齿佩戴者的下巴来引出该反射。在下颌休息和中度咬紧（个体最大咬肌肌电图活动的40%）时，从偏好咀嚼侧的咬肌获取表面肌电图记录。所有受试者至少记录到一次下颌反射，与休息时相比，咬紧时反射的发生率降低。然而，在两种实验条件下，义齿佩戴者的反射发生率均增加，而两个牙列状态组之间在潜伏期、持续时间和幅度值上观察到微小差异。这些结果表明，在当前实验条件下，牙周韧带感受器可能会抑制反射活动。佩戴义齿时预计会有多种感觉相互作用。然而，丙烯酸义齿基托对黏膜感受器的刺激提供了一种特殊的感觉反馈来源。由于与休息实验相比，义齿佩戴者在咬紧时下颌反射的发生率也降低，因此可以推测黏膜感受器具有潜在的抑制作用。根据本研究的结果，牙齿缺失和全口义齿修复不会严重干扰所研究的反射活动。
