Our results supported the use of single-component adhesive systems in cavities prepared using Er:YAG laser. The step of acid etching must be maintained for the whole cavity walls in regard of the microleakage values.

The application of Fortify (Bisco, Lombard, IL), an unfilled resin, to the surface of composite resin restorations is intended to fill in defects in the surface that persist despite polishing, improve marginal integrity, and increase these materials' resistance to abrasion. The aim of this study was to observe the surface texture by scanning electron microscopy and measure the microhardness of the surface. For each sample of composite resin covered with glaze, 40 measurements were made of the thickness of the resin. Measurements of the Vickers microhardness included three samples of composite resin, three samples of glaze, and six samples of composite resin covered with glaze. A relationship was established between microhardness and thickness. Scanning electron microscopy showed a noticeable improvement in the surface texture. Nevertheless, areas were seen in which glaze seemed very thin or even completely absent. Measurements of the thickness ranged from 0-70 microm. The mean microhardness of composite resin was 65.8 +/- 0.7, while the mean hardness of glaze was 7.3 +/- 0.7. The microhardness of the double layer was reduced, depending on the thickness of the glazing resin. The capacity of glaze to mask surface defects of composite resin was shown, but it was difficult to obtain a regular surface with liquid resin. The application of this product caused a decrease of the microhardness of the composite resin's surface.

Our systematic review could not specify which type of post and core system should be used when two or three dentine walls remain. More RCTs are needed to confirm whether fibre-reinforced post and core systems are superior and to clarify the influence of the remaining tooth structure on the treatment outcome of the different post and core systems available. Well-defined inclusion criteria focusing on the number of dentine walls (two or three) should be used.

No abstract

This study was conducted to compare the shear bond strengths of composite resin bonded to Er:YAG laser or bur-prepared dentin surfaces using three self-etching adhesive systems. The occlusal surfaces of 120 human third molars were ground flat to expose dentin. The dentin was prepared using either a carbide bur or an Er:YAG laser at 350 mJ/pulse and 10 Hz (fluence, 44.5 J/cm(2)). Three different self-etching adhesive systems were applied: iBond, Xeno III and Clearfil SE Bond. Rods of composite resin were bonded to dentin surfaces and shear bond tests were carried out. Both dentin surfaces after debonding and resin rods were observed using a scanning electron microscope. When the Xeno III was used, no difference was observed on shear bond strength values when bur and Er:YAG laser were compared. When using iBond and Clearfil SE Bond, bond strength values measured on Er:YAG-laser-prepared surfaces were lower than those observed on bur-prepared surfaces. The absence of smear layer formation during the preparation of the dentin by the Er:YAG laser did not improve the adhesion values of self-etching adhesive systems.