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


METHODS
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.


RESULTS
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.


CONCLUSIONS
Different Er:YAG laser parameters were effective for ablation of hard tissues, creating an irregular and microretentive morphological pattern without hard tissue damage.
Freitas
Patricia Moreira
PM
Department of Restorative Dentistry, School of Dentistry, University of São Paulo, São Paulo, Brazil.
Navarro
Ricardo Scarparo
RS
Barros
Juliana Almeida
JA
de Paula Eduardo
Carlos
C
D003737:Dental Cavity Preparation / Q000379:methods*; D003743:Dental Enamel / Q000648:ultrastructure*; D003804:Dentin / Q000648:ultrastructure*; D006801:Humans; D053844:Lasers, Solid-State; D008855:Microscopy, Electron, Scanning; D008963:Molar