Effect of Er-YAG laser on acid resistance of hybrid layer

Aim: The aim of this study was to evaluate the acid resistance of the hybrid layers formed with self-etch and total-etch adhesive systems to Er-YAG laser and SiC paper treated dentin surfaces using scanning electron microscopy. Method: Occlusal enamel of 16 third molars were ground flat using 600 grid SiC paper to obtain superficial dentin surfaces. Strong (Xeno III), intermediate strong (AdheSE) and mild (TriS Bond) self-etch and total- etch (XP Bond) adhesive systems were bonded directly to the SiC paper or ER:YAG laser (Versa Wave; 3Hz /160mJ) treated dentin surfaces. Specimens were restored with composite resin (Filtek Z250) and then sectioned perpendicular to the bonded surfaces into two halves using Isomet. Following immersion in 10% neutral formalin for 24 hours, the specimens were polished and were treated with 10% H3P04 for 5 sec and 5% NaOCl for 5 min. Then the specimens were gold sputter coated and observed using SEM (JSM 6335F JEOL). Results: Regardless of the Er:YAG laser application, self etch and total etch adhesives produced acid resistant hybrid layers with various thickness. Resin tags produced with Xeno III, AdheSE and XP Bond were longer in Er:YAG laser treated dentin whereas with TriS Bond resin tags could only be achieved after laser application. Conclusion: Er:YAG laser application did not affect the acid resistance of the hybrid layers formed with strong, intermediate strong self-etch and total-etch adhesive systems however increased the resin tag formation of the mild self-etch adhesive TriS Bond.