Preparation and Characterization of Sodium Aluminum Silicate-Polymer Composites and Effects of Surface Roughness and Scratch Directions on Their Flexural Strengths

Abstract

Although efforts have been put into the research in polymer-infiltrated ceramic network composites (PICNs), data are needed to understand the relationship between surface roughness and flexural strength. In this work, a novel dental restorative composite was fabricated via infiltrating mixtures of Bis-GMA/TEGDMA and UDMA/TEGDMA into partially sintered porous sodium aluminum silicate blocks and curing. Bars with different surface conditions were produced by sanding with abrasive and polishing. Flexural strength was measured using three-point-bending. Scanning electron microscopy (SEM) was employed to observe the microstructure of surface areas. One-way analysis of variance was applied for statistical calculations, with p < 0.05 being considered significant. Weibull plots were used to evaluate the reliability of flexural strength. The results demonstrated that the flexural strength of the resultant composites was affected by the scratch direction and the value of roughness. The flexural strength increased with decrease of surface roughness. A higher strength value was found for parallel types than for vertical types with nearly the same surface roughness. A large roughness value and a scratch direction perpendicular to tensile stress produced a low Weibull modulus. Of particular importance with this work is that these factors should be taken into consideration when using PICNs as dental restorative composites.

Characterization of Heat-Polymerized Monomer Formulations for Dental Infiltrated Ceramic Networks

“…As a result, degree of conversion is independent of the amount of TEGDMA (as long as this is over 30 wt% when formulated with BisGMA). A study by Cui et al showed comparable monomer conversion of 81.9%DC for BisGMA:TEGDMA (5:5) and 81.7%DC for UDMA:TEGDMA (8:2) mixtures [47]. This study used comparable experimental settings as they heat-polymerized with 1 wt% BPO at 70 • C for 8 h. (5:5) and 81.7%DC for UDMA:TEGDMA (8:2) mixtures [47].…”

“…A study by Cui et al showed comparable monomer conversion of 81.9%DC for BisGMA:TEGDMA (5:5) and 81.7%DC for UDMA:TEGDMA (8:2) mixtures [47]. This study used comparable experimental settings as they heat-polymerized with 1 wt% BPO at 70 • C for 8 h. (5:5) and 81.7%DC for UDMA:TEGDMA (8:2) mixtures [47]. This study used comparable experimental settings as they heat-polymerized with 1 wt% BPO at 70 °C for 8 h.…”

“…Cui et al used similar formulations for infiltration of silica-based ceramic networks [47]. They measured an elastic modulus for the final PICN material of 18.7 GPa for BisGMA:TEGDMA (5:5) and 18.9 GPa for UDMA:TEGDMA (8:2) formulations, both values closely matching the dentin elasticity.…”