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

Background and Objective: The purpose of the present study was to assess wh ether "scan irradiation" with a pulsed Nd:YAG laser could produce changes i n intrapulpal nerve activities and pulpal blood flow and to investigate whe ther it would cause tissue damage in the pulp. Study Design/Materials and Methods: The pulsed Nd:YAG: laser was used to ir radiate, in a scanning manner, the canine tooth pulp in sodium pentobarbito ne 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 obser vation was performed to detect lasing-induced tissue changes. Results: Pulpal compound action potentials evoked by various external stimu li were significantly reduced (P < 0.05) and unit firings were observed in both functional single A delta- and C-fibers during irradiation. Unit respo nses to external mechanical stimulation of the dentin completely disappeare d after "scan irradiation" with the pulsed Nd:YAG laser. Histologic observa tion 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. (C) 2000 Wiley-Liss, Inc.