Effect of Er,Cr:YSGG on bond strength and microleakage of dentin bonded to resin composite with different distance and irradiation time

Background: To explore the surface modification of dentin using Er,Cr:YSGG phototherapy and bonding system on the shear bond strength and microleakage scores at two different distances and times of laser irradiation. Materials and Methods: Ninety disease-free third molars were collected for the experiment. The four laser groups were divided on the basis of non-contact mode distance and time of irradiation: Group-I: Distance of 1 mm with duration of 60 s; Group-II: Distance of 1 mm with duration of 120 s; Group-III: Distance of 2 mm with duration of 60 s and; Group-IV: Distance of 2 mm with duration of 120 s. The surface for control group (Group-EB: Etch & bond group) was treated with etch and rinse bonding regime. Specimens from all the groups were assessed for shear bond strength and microleakage scores. Samples from all groups were immersed in 2% methylene blue for 24 h and assessed under a digital microscope for microleakage. Results: The lowest bond strength and microleakage was observed in the control group EB. The maximum bond strength score was observed in Group-IV with mean scores 23.41 +/- 1.83, while the maximum microleakage scores were observed in Group-II and Group-IV with mean scores 1.0 +/- 0.36 and 1.0 +/- 0.11, respectively. The lowest bond strength and microleakage among laser groups was observed in Group-II and Group-Ill, respectively. However, specimens in laser groups showed comparable bond strength and microleakge scores (p > 0.05). For bond strength and microleakage values, analysis of variance showed significant difference among the study groups (p < 0.001). Using Tukey post hoc test, bond strength and microleakage of laser groups showed statistically significant values than EB group. Conclusion: Use of phototherapy using Er,Cr:YSGG for dentin surface treatment has the potential for clinical application in comparison to conventional conditioning technique. Increasing the distance of laser application and time of irradiation has significant effect on the shear bond strength and microleakage scores of dentin bonded to resin composite. However, further in-vitro analysis should be undertaken in order to prove such findings.