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The use of Er:YAG laser for cavity preparation: an SEM evaluation.

Research paper by Patricia Moreira PM Freitas, Ricardo Scarparo RS Navarro, Juliana Almeida JA Barros, Carlos C de Paula Eduardo

Indexed on: 20 Jun '07Published on: 20 Jun '07Published in: Microscopy Research and Technique



Abstract

The purpose of this study was to evaluate morphological changes in cavities prepared by the Er:YAG laser (2.94 mum) at different parameters of irradiation and by a diamond bur.Cavities were prepared on 27 human molars (n = 3): G1, 15 Hz/160 mJ enamel/6 Hz/200 mJ dentin; G2, 15 Hz/180 mJ enamel/6 Hz/200 mJ dentin; G3, 15 Hz/160 mJ enamel/6 Hz/250 mJ dentin; G4, 15 Hz/180 mJ enamel/6 Hz/250 mJ dentin; G5, 15 Hz/180 mJ enamel/10 Hz/180 mJ dentin; G6, 15 Hz/160 mJ enamel/10 Hz/180 mJ dentin; G7, 15 Hz/160 mJ enamel/10 Hz/160 mJ dentin; G8, 15 Hz/180 mJ enamel/10 Hz/160 mJ dentin; G9, diamond bur. For SEM analysis, samples were fixed (2.5% glutaraldheyde, 12 h, 4 degrees C), dehydrated (25-100% ethanol), dried, and sputter-coated with gold.Despite the changes on energy and repetition-rate settings, all laser-treated samples showed no evidence of thermal damage or signs of burning and melting. Er:YAG laser ablated dental hard tissues showed exposed enamel prisms, dentin surface without smear layer, and opened dentinal tubules.Different Er:YAG laser parameters were effective for ablation of hard tissues, creating an irregular and microretentive morphological pattern without hard tissue damage.