Louca C, Vidgeon S D, Cadden S W, Linden R W
Craniofacial Biology Research Unit, King's College London, Strand, England, U.K.
Arch Oral Biol. 1998 Jan;43(1):55-63. doi: 10.1016/s0003-9969(97)00085-x.
Electromyographic (EMG) experiments were undertaken to investigate the jaw reflexes evoked by activation of gingival receptors in 12 humans. EMG recordings were made from an active masseter muscle whilst ramp-plateau mechanical stimuli were applied to the gingiva. Stimuli with a constant rate of rise (0.2 N/msec) and a variable plateau force (up to 2 N), evoked a complex set of short- and long-latency inhibitory and excitatory responses. These occurred as a sequence of inhibition-excitation-inhibition-excitation, although not all of these elements were seen on every occasion. The median thresholds of these four responses ranged from 0.5 to 1 N but overall there were no significant differences between them (p > 0.05, Friedman's ANOVA). In other experiments, the same reflexes were recorded in response to application to the gingiva of 1 N ramp-plateau stimuli (5 msec rise time) and 1 N tap stimuli applied to the adjacent tooth. The application of a local anaesthetic agent to the stimulated gingiva produced reductions in the mean magnitude of almost all the responses but these were significant (p < 0.05; ANOVA) only for the long-latency inhibitions evoked by ramping the gingiva and the long-latency excitations evoked by either stimulus. It is concluded that mechanoreceptors in the gingiva can mediate long-latency inhibitory and excitatory jaw reflexes, and that these receptors may also contribute to long-latency reflexes evoked by tapping teeth. The scarcity of effects of gingival anaesthesia on the short-latency reflexes may be due to such responses being mediated by receptors deeper in the periodontium.
进行了肌电图（EMG）实验，以研究12名受试者中牙龈感受器激活所诱发的下颌反射。在向牙龈施加斜坡-平台机械刺激时，从活动的咬肌进行EMG记录。具有恒定上升速率（0.2N/毫秒）和可变平台力（高达2N）的刺激诱发了一系列复杂的短潜伏期和长潜伏期抑制性和兴奋性反应。这些反应以抑制-兴奋-抑制-兴奋的顺序出现，尽管并非每次都能观察到所有这些成分。这四种反应的中位数阈值范围为0.5至1N，但总体而言它们之间没有显著差异（p>0.05，弗里德曼方差分析）。在其他实验中，记录了对牙龈施加1N斜坡-平台刺激（上升时间5毫秒）以及对相邻牙齿施加1N轻敲刺激时的相同反射。向受刺激的牙龈局部应用麻醉剂后，几乎所有反应的平均幅度均降低，但仅对牙龈斜坡刺激诱发的长潜伏期抑制和任何一种刺激诱发的长潜伏期兴奋有显著影响（p<0.05；方差分析）。得出的结论是，牙龈中的机械感受器可介导长潜伏期抑制性和兴奋性下颌反射，并且这些感受器也可能有助于牙齿轻敲诱发的长潜伏期反射。牙龈麻醉对短潜伏期反射影响较小可能是由于此类反应由牙周膜中更深层的感受器介导。
