A Micro-Raman Spectroscopic Comparison of the Dentin/Resin Interface of Laser- and Mechanically-prepared Tooth Cavities.

Purpose: To investigate in vitro the receptivity to the resin bonding process of Er:YAG-laser-prepared dentin surfaces compared to that of tooth cavities prepared with a conventional diamond bur. Materials and Methods: Fifty extracted human teeth free of caries were divided into two preparation groups of 25 teeth each. An Er:YAG laser was used to prepare cavities in one group, and a conventional diamond bur was used in the other. In each preparation group, 13 teeth were filled with the composite Diamond Crown and 12 with Z100 MP. The dentin/resin interface properties of the two different restorative compounds were investigated by visible light micro-Raman spectroscopy (μRS) and scanning electron microscopy (SEM). Results: The measured Raman spectra showed typical resonance peaks of dentin. Resin contributions to the Raman spectra were also detected and were used to monitor the interface properties of the boundary region. In both mechanically and laser prepared samples, the diffusion depth of the Diamond Crown composite in dentin was limited to ca 10 μm. Deeper diffusion was observed at the boundary of dentin and Z100 MP. Conclusion: Under the conditions of this study, there were no appreciable differences between mechanically and laser-prepared samples in terms of dentin/resin interface characteristics. The obtained results again confirmed the validity of micro-Raman spectroscopy as a noninvasive method of examining the interaction between dentin surface and biomaterials. Knowledge thus gained is valuable in planning new dental materials to be employed specifically when laser technology is used. [ABSTRACT FROM AUTHOR]