Morphological evaluation of enamel and dentin irradiated with 9.6μm CO2 and 2.94μm Er:YAG lasers

T.M. Marraccini,  L. Bachmann,, H.A. Wigdor,  J.T. Walsh Jr. A. Stabholtz,  and D.M. Zezell 1

Laser Physics. Lett. 2, No. 11, 551–555 (2005)

Abstract: Background: The objective was to evaluate the morphology of enamel and dentin irradiated with Er:YAG (2.94 μm) and CO2 (9.6 μm) lasers. Methods: Six groups were evaluated: G1 – CO2 irradiated enamel (3 W); G2 – CO2 irradiated dentin (3 W); G3 – CO2 irradiated enamel (7 W); G4 – CO2 irradiated dentin (7 W); G5 – Er:YAG irradiated enamel (0.16 W); G6 – Er:YAG irradiated dentin (0.16 W). Results: The morphological pattern of Er:YAG laser irradiated enamel and dentin has a rough aspect with a clear exposition of the prisms and dentinal tubules. The melted surfaces covering the CO2 laser irradiated enamel and dentin, occlude the dentinal tubules and the enamel prisms. Conclusion: The rough pattern after Er:YAG laser irradiation, which originates from the micro-explosion of water, does not occlude the dentinal tubules, whereas the surface morphology after CO2 laser irradiation, which originated from the temperature rise above hydroxyapatite melting point, shows dentinal tubules occlusion and tissue melting. Clinical implications: These changes influence the tissue properties such as increase of the enamel acid resistance or decrease the bond strength between the tissue and composite resin.