Dentin treatment with MMPs inhibitors does not alter bond strengths to caries-affected dentin

Abstract

Objectives This study aimed to investigate if the use of protease inhibitors (EDTA and chlorhexidine) may influence microtensile bond strength (MTBS) of an etch-and-rinse adhesive system to caries-affected human dentin. Methods Flat middle coronal dentin surfaces with a central region of caries-affected dentin surrounded by sound dentin were bonded with Adper Scotchbond 1 after: (1) etching with 35% H 3PO 4; (2) etching with 0.1 M EDTA and (3) 35% H 3PO 4-etching followed by 5% chlorhexidine application. Resin composite build-ups were constructed incrementally and trimmed to yield hourglass specimens (0.8 mm 2 bonded area) that contained sound or caries-affected dentin (confirmed after debonding by microhardness measurements – KHN). Bonded specimens were tensioned at 0.5 mm/min. Data were analyzed by ANOVA and multiple comparisons tests ( p < 0.05). Failure mode analysis was performed by scanning electron microscopy (SEM). Results H 3PO 4, EDTA and chlorhexidine pre-treatments yielded similar MTBS values, in both dentin substrates. Bond strength to sound dentin was significantly higher than that to caries-affected dentin after H 3PO 4-etching. Caries-affected dentin exhibited lower KHN than sound dentin. Conclusions Conditioning of caries-affected dentin with EDTA or a combined use with H 3PO 4 and chlorhexidine may be proposed as these protease inhibitors do not reduce MTBS to caries-affected dentin if compared to conventional H 3PO 4 treatment.