Effect of a chemo-mechanical caries removal system (CarisolvTM) on dentin topography of non-carious dentin

The purpose of the present study was to examine the morphology of healthy dentin surfaces after treatment with CarisolvTM followed by conditioning with phosphoric acid and EDTA, since surface morphology may be of interest for dentin bonding. Another purpose was to evaluate the effect of treatment with CarisolvTM on healthy non-carious dentin surfaces with exposed collagen fibers. Scanning electron microscopy was utilized to carry out a detailed morphological examination of the dentin surfaces with regard to presence or absence of both smear layer and collagen fibers. Twelve premolars extracted for orthodontic reasons from young adults were used. The two etchants appeared to have produced two distinctly different surfaces. Etching with phosphoric acid following CarisolvTM treatment resulted in a porous dentin surface, while EDTA etching without prior CarisolvTM treatment appeared to have uncovered an intact collagen network. In contrast, the surfaces treated with CarisolvTM prior to EDTA etching displayed smooth intertubular surfaces with only occasional fibers. Apparently, the ability of EDTA to expose collagen in the dentin surface is counteracted or inhibited by the CarisolvTM treatment. Furthermore, it cannot be excluded that the CarisolvTM treatment in itself may have dissolved collagen fibers. Since most bonding systems claim bonding to the collagenous component of dentin, the question arises which of the etched surfaces is preferable and to what degree the collagenous component contributes to bonding strength. Further studies are thus needed to evaluate the micromechanical retention of a restoration to the different surfaces described in the present study.