Effect of the photoinitiator system on the properties of a dental material based on a hybrid polymer

Abstract

<p><strong>Objective:</strong> In this study, the effects of two different cure protocols upon the properties of composites using a hybrid-polymer as dental resin were evaluated. <strong>Material and Methods:</strong> Two distinct dental composites were prepared, one containing a mixture of TEGDMA/bis-GMA (50:50) and, another containing a mixture of TEGDMA/p-MEMO (50:50), [p-MEMO: oligomeric inorganic precursor]. Both composites were polymerized with lucirin and canphorquinone as photoinitiators. The composites were made with a 70 % wt of inorganic filler. Flexural strength was evaluated with a universal test machine and the degree of conversion was measured by infrared spectroscopy. A helium pycnometer was used to obtain polymer shrinkage data. Sorption tests were performed and SEM microscopy was used to show deleterious effects upon the resins’ surfaces. <strong>Results:</strong> The sample base on TEGDMA/p-MEMO polymerized with lucirin (L-T/p) showed the best values of the monitored properties. <strong>Conclusion</strong>: Lucirin is the most suitable photoinitiator for dental composites containing hybrid polymers.</p><p><strong>Keywords</strong></p><p><strong></strong>Dental resins; Flexural strength; Hybrid polymer; Photoinitiator system; Polymerization shrinkage.</p>