Franzén O G, Ahlquist M L
Department of Psychology, University of Uppsala, Sweden.
Behav Brain Res. 1989 May 1;33(1):1-11. doi: 10.1016/s0166-4328(89)80013-0.
The tooth pulp has many attractive features for the study of peripheral pain mechanisms because of its rich innervation, its unique distribution of nerve fibers and its general disposition to give rise to pain upon stimulation. An experimental model has been developed for simultaneous recordings of intradental multi-unit A-delta nerve activity and the subjective intensity and quality of pain evoked by tooth pulp stimulation in conscious, alert humans. The only teeth to be considered for this kind of investigations are those having such a periodontal condition that they have to be extracted. The nerve activity was recorded from two electrodes placed in the dentin on the labial tooth surface, one at the level of the most incisal part of the pulp, and the other as far apically as possible. Brief cold stimulation was produced by using evaporating ethyl chloride administered between the recording electrodes. The magnitude of perceived pain was estimated by means of an intermodal matching technique (finger span) in combination with verbal descriptors. Of three response criteria selected--average response amplitude, peak amplitude and area under the response curve (integral)--for describing the relationship between intradental nerve activity and sharp, shooting pain, the integral yielded the highest mean correlation coefficient.
牙髓因其丰富的神经支配、独特的神经纤维分布以及受到刺激时通常会引发疼痛的特性，成为研究外周疼痛机制的理想对象。目前已建立了一种实验模型，用于同时记录清醒、警觉的人类在牙髓受到刺激时，牙内多单位A-δ神经活动以及所诱发疼痛的主观强度和性质。这类研究中唯一可考虑的牙齿是那些因牙周状况必须拔除的牙齿。神经活动通过置于唇侧牙面牙本质上的两个电极进行记录，一个位于牙髓最切端部分的水平，另一个尽可能靠近根尖。通过在记录电极之间喷洒蒸发的氯乙烷来产生短暂的冷刺激。借助多模态匹配技术（手指跨度）结合语言描述来估计疼痛感知的程度。在用于描述牙内神经活动与尖锐、刺痛之间关系的三个选定反应标准——平均反应幅度、峰值幅度和反应曲线下面积（积分）——中，积分产生了最高的平均相关系数。
