Evaluation of mechanical, optical, and fluoride-releasing properties of a translucent bulk fill glass hybrid restorative dental material.

OBJECTIVE: Measure and compare the mechanical properties, translucency, and fluoride-releasing capabilities of EQUIA Forte HT against Fuji IX GP and ChemFil Rock. MATERIALS AND METHODS: Ten specimens of each material were fabricated for compressive strength (CS), flexural strength (FS), and surface hardness analysis at 24 h and 7 days. The L*a*b* values were measured against a black-and-white background using a spectrophotometer to analyze the translucency parameter (TP). Fluoride release was recorded after 2 months of immersion in distilled water. The mean data was analyzed by 1- and 2-way ANOVA (α = 0.5). RESULTS: EQUIA Forte HT showed higher CS, surface hardness, and FS values (p < 0.05) compared with Fuji IX GIC, while no significant difference was found in FS values between EQUIA Forte HT and Chemfil Rock (p > 0.05). The EQUIA Forte HT exhibited significantly higher translucency in comparison to both ChemFil Rock (p < 0.001) and Fuji IX GICs (p < 0.05). An increase (p > 0.05) of fluoride release was observed for EQUIA Forte HT. CONCLUSION: The EQUIA Forte HT Glass-ionomer cements (GIC) offers enhanced translucency, improved strength, and enhanced fluoride-releasing properties compared to the traditionally used Fuji IX GIC and ChemFil Rock GICs. This material might have a wide range of clinical applications due to its improved strength and optical properties. CLINICAL SIGNIFICANCE: Glass-ionomer dental restorative materials possess unique advantageous characteristics. However, its poor mechanical and optical properties have typically limited its clinical applications. Efforts to improve these properties have resulted in enhanced GICs. EQUIA Forte HT GIC offers enhanced mechanical and optical properties with potential applications in posterior and anterior restorative procedures.

In vitro analysis of monomer leaching in modern dental materials: CAD milled, printed, traditional heat-processed, and auto-polymerizing denture base resins.

PURPOSE: Denture fabrication has shifted from traditional heat-processed and auto-polymerizing materials to computer-aided design and computer-aided manufacturing (CAD-CAM) milled and printed materials. The monomer in traditional materials can induce an allergic reaction in some patients. With the rise in the edentulous population and increasing demand for the fabrication of dentures, these newer materials should be studied for monomer leaching. The purpose of this study was to evaluate the ratio of residual monomer in materials being used for denture bases: CAD-milled polymethylmethacrylate (PMMA), printed denture base resin, heat-processed PMMA, and auto-polymerizing PMMA comparatively. MATERIALS AND METHODS: Milled, printed, heat-activated, and auto-polymerizing denture base specimens (n = 3 for each group, each test run three times) were fabricated according to manufacturer recommendations. Specimens were first immersed in deuterated chloroform (CDCl3), a deuterated organic solvent, to evaluate monomer leaching and to observe physical properties of the materials. NMR spectroscopy was used to evaluate the dissolution of materials and residual monomer to crosslinked polymer ratios at 1, 4, and 9 days. A second group of specimens was then immersed in deuterium oxide (D2O) to evaluate if the residual monomers would leach out of the system. The solution was then analyzed using nuclear magnetic resonance (NMR) spectroscopy for 1 month. The deuterated forms of chloroform (CDCl3) and water (D2O) were used to enable sample characterization by NMR. RESULTS: While the heat-processed, auto-polymerizing, and milled specimens possessed residual monomers, no significant monomer leaching was noted in the printed specimen, while immersed in CDCl3. Similarly, the printed specimen was most resistant to dissolution, as compared to the rest; dissolution of the specimen is indicative of little to no cross-linking. No detectable dissolution of monomer was seen when all specimens were immersed in D2O for up to 1 month. CONCLUSIONS: Residual monomers were not found in the printed denture material in this study in either CDCl3 or D2O, whereas CAD-milled and traditionally processed denture bases still have residual monomers within their respective systems when immersed in organic solvent. None of the specimens tested leached monomers into D2O.