Mineral-to-matrix ratio of caries-affected dentin treated with biomimetic analogs using the dentin fluid and a remineralizing solution as ion donors

Abstract

OBJECTIVES: To evaluate the remineralizing potential of biomimetic analogs applied to caries-affected dentin (CAD) using the simulated body fluid (SBF) and a remineralization solution as Ca²⁺ and PO₄^3- ions sources. METHODS: Flat dentin surfaces from caries-free molars (N = 111) were subjected to a biological protocol (Streptococcus mutans) to induce dentin caries in vitro. The mineral and organic content of sound (SD), infected (ID), CAD, and CAD etched with phosphoric acid (CAD-PA) were determined to validate the protocol. After that, CAD-PA was treated with 100,000 µg/mL sodium trimetaphosphate (STMP) and 500 µg/mL polyacrylic acid (PAA), alone or combined (n = 6/group), applied for 1 min. Teeth were kept under intrapulpal pressure with SBF for 14 days. Next, the mineral-to-matrix ratio (MMR) and surface morphology were evaluated by ATR-FTIR and SEM. Statistical analyses were performed using RM-ANOVA/Sidak and Kruskal-Wallis (α = 5%). RESULTS: The MMR was statistically different among the dentin substrates (p < 0.001). CAD showed a lower MMR than SD; the lowest MMR was seen when CAD was etched with PA (CAD-PA). However, no change in MMR was observed 14 days after the application of STMP, PAA, or STMP+PAA on CAD-PA. CONCLUSIONS: The microbiological protocol produced a carious dentin that could be partially removed, resulting in a CAD-like substrate. Also, the application of the biomimetic analogs was ineffective in increasing the surface mineral content of the etched CAD after 14 days, even when a REM solution was used as a source of calcium and phosphate ions. CLINICAL SIGNIFICANCE: The functional remineralization of caries-affected dentin using the dentin fluid and a mineralizing solution as sources of calcium and phosphate ions did not improve using biomimetic analogs of non-collagenous dentin proteins.