Effect of Dentin Surface Pretreatment With Chitosan Nanoparticles on Immediate and Prolonged Shear Bond Strength of Resin Composite: An in Vitro Study

Introduction: The objective of this study was to evaluate the impact of chitosan nanoparticles’ pretreatment of dentin surface on the macro shear bond strength of resin composite, both immediately and over an extended period. Methods: Thirty caries-free, unrestored human premolars were randomly assigned to six study groups. The dentin surface of the intervention groups underwent pretreatment with 0.2% chitosan and 0.05% NaF solutions for 1 minute. A standard etch-and-rinse adhesive procedure was performed for all the study groups. After 24 hours, half of the specimens underwent a macro shear bond strength test at a crosshead speed of 1 mm/min, whereas the other specimens underwent the same procedure after 300 thermal cycles between 5 and 55°C with a 30-second dwell time in the thermocycling device. Results: The study found that the type of dentin surface treatment agents did not significantly affect the shear bond strength (P = 0.52). However, there were statistically significant differences between immediate and prolonged shear bond strength in the chitosan (P < 0.01) and the control groups (P = 0.005). On the other hand, there were no significant differences between the immediate and prolonged shear bond strength in the NaF group (P = 0.997). Conclusion: Dentin pretreatment with 0.2% chitosan solution did not significantly affect the shear bond strength of the etch-and-rinse adhesive system. Pretreatment with NaF maintained the shear bond strength of the adhesive to dentin after 300 thermal cycles.