Gelatinolytic Activity and Adhesion to Bacterial Induced Caries-affected Dentin

Objectives: The aim of this in vitro study was to investigate if the interfacial enzymatic activity and adhesion performance of artificial caries-affected dentin (ACAD) simulate those of natural caries-affected dentin (NCAD).
Methods: Thirty dentin specimens were prepared from human molars to determine the interfacial gelatinolytic activity using in situ zymography and adhesion studies [micro-permeability and bond strength (µTBS)]. Groups were assigned according to the type of dentin: artificially formed caries CAD (ACAD), natural caries (NCAD) or sound. ACAD was produced by incubating dentin with Streptococcus mutans in a chemically defined medium (CDM) with 1% sucrose for 7 days at 37 ⁰C under anaerobic condition. Daily replacement of fresh CDM and the sterility and the pH of the culture was monitored. Adhesion studies employed Single Bond Universal bonding system in self-etch mode. Data were individually processed and analyzed by ANOVA and post-hoc tests (α=0.05).
Results: Enzymatic activity of ACAD was similar to sound dentin, while lower than NCAD that elicited the highest activity (p<0.05). Interfacial micro-permeability intensity, at the HL or underlying dentin (5 µm below interface), was similar to all types of dentin (p>0.05). On the other hand, substrate permeability was higher for NCAD than for ACAD. The higher sealing ability was detected in sound dentin. Bond strengths to ACAD was higher than to NCAD. However, the highest µTBS was observed in sound dentin (p<0.05).
Conclusions: Artificial caries-affected simulate neither gelatinolytic activity nor bonding performance found in natural caries-affected dentin.