Surface Roughness and Hardness of Dental Resin-Composites Intended for Bulk-fill Placement

Abstract

Objective: To evaluate the surface roughness and hardness of high and low consistency bulk-fill resin-composites and to compare them with other conventional resin-composites.Materials and Methods: The study was divided into five groups according to type of resin-composite as follows: group I: Low consistency bulk-fill SureFil SDR Flow (SF), group II: Low consistency bulk-fill Venus Bulk Fill (VB), group III: High viscosity bulk-fill Tetric EvoCeram, group IV: Conventional Beautifil Flow Plus F03 (BF) and group V: Conventional GrandioSo (GS). A total of 10 disc-shaped specimens (15 mm diameter × 2 mm thickness) were prepared from each material for both surface roughness and hardness testing. Specimens were stored in distilled water for 24 hours before testing. For the determination of surface roughness values, Surface Profile Gage (Positector, SPG, Deflesko Corporation, New York, USA) was used. Hardness testing was carried out using Digital Microhardness Tester (Zwick/Roell, IDENTEC, ZHVµ-S, West Midlands, England). Data were analyzed using a One-way ANOVA and Bonferroni post-hoc test. P < 0.05 was considered statistically significant. Results: Considering different filler loading, monomer system and consistency of the material, the hardness values ranged between 49.8 and 97.3 (VHN) and the surface roughness ranged between 5.6 and 17.1 (µm). One way ANOVA revealed a significant differences between the studied materials for surface roughness (P = 0.000) and microhardness (P = 0.000). Bonferroni post-hoc test revealed significant differences between surface roughness results of all studied resin-composites (p < 0.05). There was also significant differences between hardness values of all investigated resin-composites (P = 0.000) except between SF and VB (P = 0.701). Significantly greater hardness and surface roughness were recorded for materials with higher filler loading than those with lower filler loading.Conclusions: Within the range of studied resin-composites, the values of surface roughness and hardness were principally dependent on the extent of filler loading, the type of resin system and the material consistency.