A Study on the Mechanism of Pain Elicited from the Dentin

Abstract

Dry absorbent paper applied on freshly exposed dentin surfaces produced pain in 54 of 54 tests on 18 premolars. Paper soaked in isotonic KC1 solution produced short-lasting pain in only 4 of 54 tests. On dentin surfaces exposed 1 wk. earlier, dry paper produced pain in 2 of 7 cases; but scraping with a probe regularly evoked pain. The pain produced by absorbent paper is probably elicited by a hydrodynamic mechanism and, on the basis of histological evidence, the odontoblasts play no import role in the pain response. The pulp with its nerve fibers extending into the pulpo-dentinal zone may function as a mechanorecep-tor. Most painful stimuli applied to the intact tooth or to the exposed dentin stimulate this receptor structure mechanically.