Pulsed Nd:YAG laser irradiation of the tooth pulp in the cat: II. Effect of scanning lasing

Abstract

Background and Objective The purpose of the present study was to assess whether “scan irradiation” with a pulsed Nd:YAG laser could produce changes in intrapulpal nerve activities and pulpal blood flow and to investigate whether it would cause tissue damage in the pulp. Study Design/Materials and Methods The pulsed Nd:YAG laser was used to irradiate, in a scanning manner, the canine tooth pulp in sodium pentobarbitone anesthetized cats. The compound action potentials and spike response in the functional single afferent nerve fibers were recorded while responding to various external stimuli applied to the exposed dentin. Histologic observation was performed to detect lasing-induced tissue changes. Results Pulpal compound action potentials evoked by various external stimuli were significantly reduced (P < 0.05) and unit firings were observed in both functional single A delta- and C-fibers during irradiation. Unit responses to external mechanical stimulation of the dentin completely disappeared after “scan irradiation” with the pulsed Nd:YAG laser. Histologic observation revealed that irradiation with the laser produced tissue damage in the pulp. Conclusion “Scan irradiation” with the pulsed Nd:YAG laser of cat's teeth produced alterations in the intrapulpal nerve activities, as well as caused tissue damage in the pulp. Lasers Surg. Med. 26:477–484, 2000. © 2000 Wiley-Liss, Inc.