[Use of the CO2 laser in enamel-dentin bonding procedures: experimental findings]

The objective of this study is to verify if laser (CO2) preparation of dental tissues has an effect on the quality of the seal of composite fillings. Forty-eight cavities were filled with the Scotchprep/Scotchbond 2 system, using P 50 (3M) as filling material, following the clinical protocol of the system; 40 cavities had previously been treated with a CO2 laser Sharplan 1020 (SBM). The teeth were thermocycled (240 cycles 4 degrees C/55 degrees C), then placed in a 0.5% basic fuschine solution for 48 hours after isolation of the root dentin. After inclusion and section, the penetration of the coloring agent was examined at the interface tooth-filling. This was followed by examination of the interface composite-tooth with the Scan Electronic Microscope. In order to visualize a possible alteration of the dentinal seal, 4 cavities treated with laser were placed in a 0.5% basic fuschine solution for 48 hours after isolation of the root dentin. Four reference cavities were cut with a diamond bur on a high speed handpiece. The following results were obtained: 1) the dentinal permeability of the laser-treated samples increases markedly in comparison with the reference group. 2) the filling-tooth junction of the laser-treated samples were never dye-tight (contrary to the reference samples). 3) fissures were created in the enamel and the dentin. The Scan Electron Microscopy confirms these results.