Introduction: This study aimed to enhance the mechanical properties and bioactivity of dentin through the development of an innovative dentin booster: a hydroxyapatite and gelatin-based matrix containing L-Ascorbic Acid 2-Phosphate (AA2P) and a controlled-release system. The matrix was further fortified with fluoride ions and Dentin Matrix Protein 1 (DMP1) to improve remineralization and biological response.
Materials and
Methods: A total of 186 cylindrical dentin specimens from 93 extracted human teeth were divided into five groups and treated with the following formulations: • Control group: Saline solution • Experimental groups: Hydroxyapatite nanoparticles (10 wt%) and gelatin (5 wt%) in combination with AA2P, incorporated in a controlled-release system using Poly(lactic-co-glycolic acid) (PLGA). Additionally, fluoride ions (1-2 ppm) and DMP1 (100 ng/mL) were included. The specimens underwent a 3-day pH cycling process to simulate dentin caries formation through repeated sequences of demineralization and remineralization. Mechanical and bioactivity tests were conducted, including surface microhardness at 100 and 500 µm depths, compressive strength, diametral tensile strength (DTS), solubility, and scanning electron microscopy (SEM) analysis.
Results, Conclusions, and Discussions: The control group exhibited significantly lower microhardness at both depths (p < 0.001), reduced DTS (p < 0.001), decreased compressive strength (p < 0.001), and higher weight loss (p < 0.001) compared to all experimental groups. Among the treated groups, the hydroxyapatite and gelatin-based matrix showed significantly higher compressive strength and surface microhardness (p < 0.001). The controlled-release system ensured sustained delivery of AA2P and metal cations, leading to enhanced remineralization. Fluoride ions provided additional resistance to demineralization, while DMP1 promoted dentin regeneration and improved the biological response. The microhardness was significantly higher at the 500 µm depth compared to the 100 µm depth (p < 0.001), although the difference in microhardness between depths across groups was not significant (p = 0.211).
