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

The aim of this study was to evaluate the influence of alpha-tricalcium phosphate (alpha-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 alpha-TCP group. An experimental adhesive resin was formulated with BisGMA, HEMA (66.66:33.33 wt%), and a photoinitiator system. alpha-TCP was added at 2 wt% into this base resin, and one group remained without alpha-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 (mu-TBS), Knoop hardness of dentin, and mineral deposition by microRaman spectroscopy. The experimental adhesive resin with alpha-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 alpha-TCP group was higher than the control. There was no difference for mu-TBS between groups (p > 0.05). The hardness of CAD increased in 100 and 200 mu m from the adhesive interface after three months (p < 0.05), and both groups indicated higher mineral content on CAD by micro-Raman spectroscopy. The alpha-TCP addition did not affect the dental adhesives' properties and did not change the mineral deposition and mu-TBS.

Automated summary

The study evaluated the influence of alpha-TCP on the physical-chemical properties of an experimental adhesive resin and the immediate and long-term properties of caries-affected dentin. The addition of alpha-TCP increased the initial Knoop hardness of the adhesive resin and the hardness of caries-affected dentin. There was no significant difference in other properties such as softening in solvent, polymerization rate, degree of conversion, microtensile bond strength, and mineral deposition.