Abstract :Purpose: The aim of this study was to evaluate the shear bond strength (SBS) of glass ionomer and glass carbomer cements on Er,Cr:YSGG laser or acid-etched human dentin surface.
Materials and Methods: One hundred and twenty extracted caries-free human third molar teeth were selected and occlusal enamel was removed until dentinal surface was exposed. The teeth were randomly divided into four main groups (n=30). Then four main groups were divided into three subgroups. For the dentin surface treatment; first group was etched with 37% phosphoric acid or 20% polyacrylic acid, second group was etched with Er,Cr:YSGG laser and third group was not etched served as the control group. Fuji IX GP, Fuji II LC, Dyract XP and GCP restorative materials were applied to dentin surface as 4x4 mm cylindrical block. After storing the specimens in artificial saliva at 37°C for 24 h, SBS of the restorative materials were measured with Shimadzu AGS-X 50 kN testing machine at crosshead speed of 0.5 mm/min. The fractured surfaces were examined in stereomicroscope and SEM. Statistical analysis was made using SPSS program for Windows 21.0 with Post Hoc LCD test.
Results: For Fuji IX, there is no significant difference between acid-control and laser-control groups (p>0.05); the highest bond strength values were observed with etched condition (p< 0.05). For Fuji II, there is no significant difference between acid-control groups (p>0.05); laser application showed the lowest bond strength values compared to other surface conditions (p< 0.05). For Dyract XP, acid and laser groups showed better bond strength values than control group (p< 0.05); no significant difference was found between acid-laser groups (p>0.05). For GCP group, there was no significant difference between in all conditions (p>0.05). Moreover, in all different conditions of the dentin surface treatment, bond strength values were observed highest in Dyract XP specimens and lowest in GCP specimens (p< 0.05).
Conclusions: Application of laser on dentin surface weren’t found effective on bond strengths of the restorative materials than conventional application methods. GCP glass carbomer restorative material showed weaker SBS values than expected.