Bioinspired remineralization of dentine by designed lightcuring calcium-silicate material

Objectives: Bioactive calcium-releasing composites able to remineralize dentine surface represent attractive preventive and therapeutic materials in restorative dentistry. The hypothesis of the study was that experimental restorative/ composite materials containing tailored calcium-silicate particles are able to remineralize artificially demineralized dentine. Materials and methods: Calcium-aluminosilicate powder (wTC-Ba) consisting of tri- and dicalcium-silicate, tricalcium aluminate, calcium sulphate, barium sulphate, was mixed with an experimental resin (HTP-M) containing HEMA, TEGDMA and polyacrylic acid. Gradia Direct LoFlo (GC, Japan) and Vitrebond (3M ESPE, Germany) were tested as controls. Dentin disks (0.8mm±0.2mm thick and 5.0mm±1.0mm length) were prepared from human third molars following extraction by using a saw microtome. Dentin disks were demineralized by immersion in sterile 17% EDTA solution (Ogna, Italy) for 2h, standing in vertical position using a PVC support to demineralize both the major surfaces. FTIR analysis was performed on each demineralized dentine to confirm the occurred demineralization. Each demineralized dentin disk was placed in close contact with a cement sample and stored in 20mL of simulated body fluid (DPBS) at 37 ◦C. After 7 days of soaking, all dentine disks were separated from the cement, washed with 5mL of deionized water to remove the cement deposit, and analyzed by FTIR and ESEM/EDX. Results: The experimental composite released calcium (500ppm at 3h) and formed carbonated apatite (Ap) on its surface, and induced the in situ formation of a different carbonated apatite (Ap) on the surface of demineralized dentine. Control materials did not support apatite formation or dentine remineralization. Conclusions: The released calcium was adsorbed on the dentine surface and enhances its mineralization in simulated body fluid. The study supports the concept that a calciumsilicate filled composite is a smart material able to induce apatite formation for remineralization of caries-like dentine lesions. These properties may extend the range clinical applications of composite materials