Morpho-structural aspects of Er:YAG-prepared class V cavities.
OBJECTIVE
The aim of this study was to evaluate the ability of an Er:YAG laser (2960nm) to prepare class V cavities as compared with rotary instruments.


METHODS
Twenty-six freshly extracted human molars were selected and randomly distributed in two groups. Non standardized class V cavities were prepared using (group 1) a diamond bur for enamel, plus a tungsten bur for dentin with water irrigation and (group 2) an Er:YAG laser (output parameters, enamel: 1000 mJ, 12Hz, dentin: 500 mJ, 20Hz) with a continuous flow of water.


RESULTS
The SEM examination revealed characteristic micro-irregularities of the lased samples as compared with the conventional prepared cavities: group 1, the walls of the cavities were slightly curved and a smear layer plus muds covered peripheric walls as well as the depth of the cavity; rare dentinal tubules were opened; linear and circular surface irregularities were observed on the dentin; and group 2, the walls of the cavities were irregular, jagged; photo-ablation creates a real cleavage of hydroxyapatite prisms with respect to the enamel prism pathway; an homogeneous dentin with opened dentinal tubules covered the depth of the cavities; intertubular dentin is selectively more ablated than Er-YAG the peritubular dentin.


CONCLUSIONS
Jagged outline as well as opened dentinal tubules are the main characteristics of the Er-YAG prepared class V cavities. Further investigations (ulstrastructural, histochemical properties of the lased dentin, resistance to traction of bonded resins) should be conducted.
Curti
Manlio
M
Laboratory Surfaces Interfaces. UFR Odontologie. Université de Nice Sophia Antipolis, Nice Cedex, France.
Rocca
Jean-Paul
JP
Bertrand
Marie-France
MF
Nammour
Samir
S
D003737:Dental Cavity Preparation / Q000379:methods*; D003743:Dental Enamel / Q000473:pathology; D003804:Dentin / Q000473:pathology; D006801:Humans; D066298:In Vitro Techniques; D053685:Laser Therapy; D008964:Molar, Third / Q000473:pathology