Adhesive system with alpha-tricalcium phosphate addition for mineral deposition on caries-affected dentin

Abstract

The aim of this study was to evaluate the influence of alpha-tricalcium phosphate (α-TCP) in the physical-chemical properties of an experimental adhesive resin and to analyze the immediate and long-term properties of caries-affected dentin (CAD) after selective removal to soft dentin restored with or without the α-TCP group. An experimental adhesive resin was formulated with BisGMA, HEMA (66.66:33.33 wt%), and a photoinitiator system. α-TCP was added at 2 wt% into this base resin, and one group remained without α-TCP as control. The adhesives were analyzed for softening in solvent, polymerization kinetics, and degree of conversion (DC). Human teeth naturally affected by caries were submitted to selective removal of carious dentin and were restored with the experimental adhesives. The teeth were evaluated by immediate and long-term (storage in simulated body fluid) tests: microtensile bond strength (μ-TBS), Knoop hardness of dentin, and mineral deposition by micro-Raman spectroscopy. The experimental adhesive resin with α-TCP showed higher initial Knoop hardness than the control group (p < 0.05). There was no difference regarding the softening in solvent (p > 0.05) and the DC (p > 0.05). The polymerization rate of α-TCP group was higher than the control. There was no difference for μ-TBS between groups (p > 0.05). The hardness of CAD increased in 100 and 200 μm from the adhesive interface after three months (p < 0.05), and both groups indicated higher mineral content on CAD by micro-Raman spectroscopy. The α-TCP addition did not affect the dental adhesives’ properties and did not change the mineral deposition and μ-TBS.