EFFECTS OF ND-YTTRIUM-ALUMINUM-GARNET AND HO-YTTRIUM-ALUMINUM-GARNET LASERS ON HUMAN DENTIN FLUID-FLOW AND DENTAL PULP-CHAMBER TEMPERATURE IN-VITRO

Dentine specimens were prepared from freshly extracted third molars an d initial permeability measured. Each specimen was subjected to Nd:ytt rium-aluminium-garnet (YAG) (1.06 or 1.32 mu m wavelength) or Ho:YAG ( 2.10 mu m wavelength) laser energy while temperatures in the pulp cham bers were recorded. Permeability was again measured and the surfaces e xamined by scanning electron microscopy. Six crown segments were used for each laser variable and eight permeability measurements were taken before and eight after laser exposure, while temperature was recorded during treatment. All wavelengths reduced permeability but temperatur e rises were high enough to have caused pulpal damage, indicating that shorter treatment times and lower power settings may be necessary if used in vivo. (C) 1997 Published by Elsevier Science Ltd. All rights r eserved.