RESUMO
This investigation compared the permeability of dentinal tubules after laser beam and conventional bur apicoectomies. Twenty roots were rountinely instrumented and obturated with laterally condensed gutta-percha. A bur was used to cut the apexes of 10 teeth, while the remaining 10 were cut with a laser beam carried through an optic fiber. A 35-W pulsed Nd:YAG laser system capable of cooling the irradiated area with an air and water spray supplied the power. Except for the apex, the teeth surfaces were coated with a blue wax. The samples were stored for 36 hours in a 2.5% methylene blue solution and were washed, split, and measured for dye penetration. Linear penetration in series 1 averaged 2.4 mm, while series 2 measured 0.9 mm. The laser apicoectomy appears to reduce the permeability of dentinal tubules.