Analysis of composite type and different sources of polymerization light on in vitro toothbrush/dentifrice abrasion resistance

Objectives: This study examined toothbrush/dentifrice abrasion of a photo-activated prosthetic composite (dentin and enamel variations) for the purpose of evaluating the influence of polymerization sources on abrasive wear. Methods: A photo-activated prosthetic composite material (Artglass) was assessed. Dentin and enamel variations were polymerized using a proprietary photo-curing unit with two xenon stroboscopic lamps (UniXS), and other enamel specimens were polymerized either with a laboratory photo-curing unit with three fluorescent tubes or with a high intensity unit with two metal halide lamps. All specimens were stored in water for 14 days and subjected to toothbrush/dentifrice abrasion (350 g vertical load) using an abrasive slurry (Colgate Fluoriguard) and a toothbrush (Oral-B 40). The amount of vertical loss and the surface roughness of the specimens after 20,000 strokes were determined by profilometer. Average values of groups of five specimens were compared using analysis of variance (ANOVA) and Sheffeʹs S intervals (p<0.05). Results: When polymerizing with the proprietary unit, the abrasion and surface roughness of the enamel material required respective means of 34.08 μm (±3.66) and 1.00 μm (±0.08), and the those of the dentin material required means of 42.02 μm (±5.62) and 1.23 μm (±0.20). Both abrasion and surface roughness after toothbrushing of the enamel material were significantly smaller than were those of the dentin material. The abrasion of specimens polymerized with the metal halide unit required a mean of 23.89 μm (±6.17) and demonstrated minimal wear. Conclusions: The use of a high intensity metal halide photo-curing unit effectively enhanced the abrasion resistance of the composite. Surfaces of restorations should be covered with the enamel material in order to achieve smoothness and wear resistance.