Bond stability of conventional adhesive system with MMP inhibitors to superficial and deep dentin

To evaluate the microshear bond strength (μSBS) to deep (DD) or superficial (SD) dentin (μSBS) overtime, nanoleakage (AG%), degree of conversion (DC%), water sorption (WSp), and solubility (WSl) of an adhesive system [Adper Single Bond 2(ASB)] containing matrix metalloproteinases (MMP) inhibitors [GM1489 (ASB-GM), Batimastat (ASB-BAT), or Chlorhexidine diacetate (ASB-CHX)]. ASB without inhibitor was used as control (CONTROL).

WSp and WSL were calculated based on ISO4049. DC% was analyzed using FT-IR spectroscopy. Dentin discs were used for μSBS evaluation. For AG%, resin-dentin beams were analyzed under scanning electronic microscopy. Data were analyzed using three-way ANOVA (AG% and μSBS) or ANOVA (DC%, WSp, WSl) and Tukey's HSD test.

ASB-CHX presented the lowest DC%, lowest WSp, and highest WSl. ASB-GM reached the highest immediate μSBS in SD, only different from ASB-CHX. In DD, ASB-BAT and ASB-GM had the highest μSBS, statistically different from ASB-CHX. After twelve months, ASB-GM and ASB-BAT presented higher μSBS in SD when compared to CONTROL and ASB-CHX. In DD, ASB-GM reached the highest value, which was statistically different from CONTROL and ASB-CHX. CONTROL at both dentin depths and ASB-CHX at DD did not maintain bond stability. In SD after 12 months, ASB-BAT and ASB-GM decreased AG%. In DD, only ASB-GM reduced AG%.

The ASB containing Batimastat and GM1489 maintained resin-dentin bond stability after 12 months for both dentin depths, without jeopardizing WSp, WSl, or DC% of the adhesive system. The ASB-GM presented greater μSBS after 12 months when compared with ASB.

Batimastat and GM1489 could be suitable for inclusion as an MMP-inhibitor into Single Bond to improve the bond stability to superficial and deep dentin, without jeopardize the physic-mechanical proprieties.