Mechanical/physical properties and fluoride release of a novel fluorapatite filled dental composite material

Abstract

Objective: To produce a bioactive composite that is less vulnerable to demineralization, possess remineralization activity and has antimicrobial properties to prevent recurrent caries but still has acceptable mechanical properties. Methods and materials: Fluorapatite (FA) crystals were synthesized and 50wt% was ground. Fifty wt% of the ground and intact crystals were silanized with 1.0 vol% of 3- methacryloxypropyltrimethoxysilane(MPS), analyzed with X-ray Photoelectron Spectroscopy(XPS). A 60 wt% FA were mixed with 40 wt% bisGMA/TEGDMA to produce a composite and were divide into 4 groups: ground silane FA, ground non-silane FA, intact silane FA, intact non-silane FA. Flexural strength (FS), water absorption (Wsp), water solubility (SI), Knoop microhardness (KH) and fluoride release at pH 7 and 4 were measured. A silanated glass 60wt % filled composite was the positive control. Results: XPS confirmed the salinization of FA, ground and intact.The control group showed significantly higher FS than all the FA groups (p<0.001). No significant differences in FS observed between the four FA groups (p>0.05). No significant differences in KH observed when silane ground and intact FA groups compared to control group (P>0.05). There were significant differences in KH within the FA groups. The control group after 28 days, showed significantly less Wsp (P< 0.001) compared to all other groups, and ground non silane showed the highest amount. The control group dissolved the least while the highest SI was in the ground non silane FA. There were significant differences in Sl within the FA groups (P<0.001). All FA composites, release the fluoride under pH4. Conclusion: Although the FS measurements did not reach the value that would allow the FA crystal filled composites to be used as a posterior restorative, the FS, KH, Wsp and Sl complied with the ISO standard and did reach the value for anterior composites. All FA composites, release the fluoride under pH4. The silane intact and ground FA crystal filled novel prototype composite has the most potential as a smart bioactive anterior composite material.