Effect of pretreatment with different MMP inhibitors on shear bond strength of composite to primary teeth dentin after six months of aging

Background loss of hybrid layer integrity compromises the resin-dentin bond stability. Subsequent release and activation of matrix metalloproteinase enzymes during dental restorative procedures or caries development are contributing factors to dentin-adhesive bond failure. Aim To investigate the effect of pre-treatment with different MMP inhibitors on the shear bond strength (SBS) of an etch-and-rinse adhesive (Adper Single Bond 2) to primary teeth dentin after six months of aging. Methods Sixty extracted anterior primary teeth, due to orthodontic reasons, were selected. A dentin block (6.0 mm × 6.0 mm × 2.0 mm) was obtained from each tooth. All the dentin blocks (n = 60) were pretreated for 60 s with either 0.01 M phosphate buffered saline (PBS, pH 7.2) in the control group, 2%: Chlorhexidine (CHX) solution, 2% Doxycycline (DO)solution and EDTA 17% after etching and before applying etch-and-rinse adhesive system (Adper Single Bond 2). Then composite was applied in clear teflon cylinders. The specimens were stored in artificial saliva for 6 months at 37°C and then the SBS values were determined with a universal testing machine. Representative samples were selected for visualization of the failure mode under stereomicroscope and SEM. Results No statistically significant difference observed between the SBS of the EDTA group, DO group and the control group (P value>0.05). CHX showed significantly higher SBS values compared to the other groups of the study after six months(P value=0.011). Conclusion Chlorhexidine significantly preserved the SBS of composite resin to deciduous dentin using etch and rinse adhesive Adper Single Bond 2 after 6 months of aging in artificial saliva.