Résumé
@#This study aims to compare flexural strength and flexural modulus of different resin-based composites (RBCs) and to determine the impact of dietary solvents on flexural properties. Forty specimens (12x2x2mm) for each of two conventional (Aura Easy [AE]; Harmonize [HN]) and one bulk fill (Sonic Fill 2 [SF2]) were fabricated using customised plastic moulds. Specimens were light-cured, measured and randomly divided into four groups. The groups (n=10) were conditioned for 7 days at 37°C: in one of media: air (control), artificial saliva (SAGF), 0.02N citric acid and 50% ethanol–water solution. After conditioning, the specimens subjected to flexural testing. Two-way ANOVA and one-way ANOVA (post hoc: Tukey’s or Dunnett T3 tests) were used at =0.05. Significant differences in flexural properties were observed between materials and conditioning media. Flexural strength and modulus values ranged from 124.85MPa to 51.25MPa; and 6.76GPa to 4.03GPa, respectively. The highest flexural properties were obtained with conditioning in air. Exposure to aqueous solutions generally reduced flexural properties. In conclusion, the effect of dietary solvents on flexural properties were material and medium dependent. For functional longevity of restorations, patients’ alcohol intake should be considered during material selection. Dietary advice (reduce alcohol consumption) should be given to patients post operatively.
Résumé
ABSTRACT@#High viscous glass ionomer cement (HVGIC) was recently developed for atraumatic restorative treatment (ART). However, its moisture sensitivity remains a limitation thus protective coating application is recommended. This study investigated the effect of resin coating on the surface roughness and microhardness of two HVGICs (Riva Self Cure HVGIC [RV] and Equia® Forte Fil [EQ]) conditioned in food-simulating liquids (FSLs). Fifty standard disc-shaped samples were fabricated using customised stainless-steel mould (10 × 2 mm). Coating was applied on top surface of all samples and subsequently divided into five groups: air (control), distilled water, 0.02 N citric acid, heptane and 50% ethanol-water solution. The samples were conditioned in FSLs at 37°C for seven days. Subsequently, the surface roughness and microhardness of samples were measured using optical profilometry and microhardness tester, respectively. SEM analysis was done for qualitative observation of surface morphological changes. Data were analysed using one-way ANOVA, two-way ANOVA and posthoc Tukey’s test (α = 0.05). Interestingly, the results revealed that surface roughness was significantly influenced by FSLs immersion, presence of coating and the materials itself (p < 0.001). The lowest surface roughness was found on control coated samples: RV (50.98±4.25) nm and EQ (62.77±3.92) nm, while the highest values seen on uncoated surfaces in citric acid: RV (505.26±31.10) nm and EQ (350.33±15.36) nm. RV samples had the lowest microhardness of 54.97±2.48 Vickers hardness number (VHN) post-immersion in citric acid. In conclusion, with the exception of RV conditioned in heptane and ethanol, the uncoated HVGICs generally had higher surface roughness than the coated HVGICs. HVGICs conditioned in citric acid showed the most significant increase in surface roughness and reduction in microhardness.