Evaluation of the Selected Mechanical and Aesthetic Properties of Experimental Resin Dental Composites Containing 1-phenyl-1,2 Propanedione or Phenylbis(2,4,6-trimethylbenzoyl)-phosphine Oxide as a Photoinitiator

Abstract

The goal of this study was to compare the mechanical properties of experimental resin dental composites containing a conventional photoinitiating system (camphorquinone CQ and 2-(dimethylami-no)ethyl methacrylate (DMAEMA)) to a photoinitiator system containing 1-phenyl-1,2 propanedione (PPD) with 2-(dimethylami-no)ethyl methacrylate) or acting alone phenylbis(2,4,6-trimethylbenzoyl)-phosphine oxide (BAPO). The manually produced composites consisted of an organic matrix: bis-GMA (60 wt. %), TEGDMA (40 wt. %), and silanized silica filler (45 wt. %). The composites contained 0.4/0.8 wt. %, 0.8/1.6 wt. %, and 1/2 wt. % of PPD/DMAEMA and another group included 0.25, 0.5, or 1 wt. % of BAPO. Vickers hardness, microhardness (in the nanoindentation test), diametral tensile strength, and flexural strength were assessed, and CIE L* a* b* colorimetric analysis was conducted for each composite produced. The highest average Vickers hardness values were obtained for the composite containing 1 wt. % BAPO (43.73 ± 3.52 HV). There was no statistical difference in the results of diametral tensile strength for the experimental composites tested. The results of 3-point bending tests were the highest for composites containing CQ (77.3 ± 8.84 MPa). Despite the higher hardness of experimental composites including PPD or BAPO, compared with composites with CQ, the overall results indicate that the composite with CQ still represents a better solution when used as a photoinitiator system. Moreover, the composites containing PPD and DMAEMA are not promising in terms of color or mechanical properties, especially as they require significantly longer irradiation times.