Adaptation to the cavity floor of the light-cured glass ionomer cement base under a composite restoration.

The study attempted to assess methods of prevention of the formation of a contraction gap in a cylindrical enamel and dentine cavity. The influence has been investigated of the tensile bond strength of cement/dentine and cement/composite resin and the direct tensile strength during setting of light-cured glass-ionomer cements. The interface between composite resin/cement and cement/dentine were viewed and photographed by replica techniques under an SEM (Scanning Electron Microscope). The most noticeable finding was that an enamel and dentine cavity applicated with light- and auto-cured glass-ionomer cement generally presented with a small construction gap at the tooth restoration interface. However, the light-cured glass-ionomer base (Vitrabond) exhibited significantly better tensile bond strength to dentine and resin performance than the conventional glass-ionomer tested. This study revealed that there was no clear relationship between the adhesion to dentine and the adaptation to the dentine cavity floor.