Authors:
M. Sivakumar
V Oliveira
R. Vilar
Depto. Engenharia Materiais, Instituto Superior Te´cnico, Universidade Te´cnica Lisboa, Av. Rovisco Pais n. 1, 1049-001 Lisboa, Portugal

S. Oliveira
Faculdade Medicina Denta´ria, Universidade Lisboa, Cidade Universita´ria, 1648-003 Lisboa, Portugal

The aim of this work was to study the bond strength of resin composite bonded to dentin surfaces treated with KrF excimer laser radiation, untreated surfaces, and acid-etched surfaces using a single-plane shear method. Dentin specimens cut from freshly extracted permanent molar teeth were subjected to laser treatment with a KrF excimer laser (248 nm) using a fluence of 1 J/cm². The bond strength was greater for acid-etched specimens than for laser treated or untreated specimens. The low strength of the bond to laser treated surfaces is probably due to a shift from a mixed to a cohesive rupture mechanism. It was concluded from this study that surface treatment of dentin surfaces with KrF excimer laser under the conditions described does not significantly improve the shear bond strength to composites.