Morphological evaluation of enamel and dentin irradiated with 9.6 μm CO 2 and 2.94 μm Er:YAG lasers

• Published in: Laser physics letters 2005-11, Vol.2 (11), p.551-555
• Main Authors: Marraccini, T M, Bachmann, L, Wigdor, H A, Walsh Jr, J T, Stabholtz, A, Zezell, D M
• Format: Article
• Language: English
• ISSN: 1612-2011; 1612-202X
• DOI: 10.1002/lapl.200510040

Background: The objective was to evaluate the morphology of enamel and dentin irradiated with Er:YAG (2.94 μm) and CO 2 (9.6 μm) lasers. Methods: Six groups were evaluated: G1 – CO 2 irradiated enamel (3 W); G2 – CO 2 irradiated dentin (3 W); G3 – CO 2 irradiated enamel (7 W); G4 – CO 2 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 CO 2 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 CO 2 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.