RESUMO
OBJECTIVE: The effect of different staining solutions and a bleaching procedure on color stability and surface roughness of a nanohybrid resin composite were evaluated with or without liquid resin polishing (RP). MATERIALS AND METHODS: Ninety-six disc-shaped resin composite specimens (A1 Shade, Z550 Filtek 3M ESPE, St. Paul, MN, USA) were prepared and divided randomly into two groups (n = 48). Liquid RP (BisCover LV, Bisco Inc., Schaumburg, IL, USA) was applied in one group (RP) and not in the other (P). Specimen color and surface roughness were determined using a colorimeter and profilometer, respectively. After baseline measurements, each group was divided into four subgroups (n = 12) for immersion in a control (distilled water) or three different staining solutions (ice tea, red wine, and cola) for 1 week. Color and surface roughness were then reevaluated. After measurements, all specimens were bleached using a 35% hydrogen peroxide gel. The color and surface roughness of the specimens were reevaluated. STATISTICAL ANALYSIS: Data were subjected to an analysis of variance for repeated measurements among the groups (P < 0.05). RESULTS: Staining and bleaching did not change the surface roughness of the RP and P groups (P > 0.05). Discoloration in the red wine group was higher than for the other staining solutions for the RP (P < 0.001) and P groups (P = 0.018). CONCLUSION: Application of liquid RP did not enhance the color stability and surface roughness of the composite resin restoration.
RESUMO
OBJECTIVES: The aim was to determine the effect of blood contamination and haemostatic agent application on the shear bond strength (SBS) of different adhesives to dentin. MATERIALS AND METHODS: Seventy-two extracted human molars were used in this study. Teeth were mounted acrylic in moulds. Mesial and distal surfaces were removed to obtain flat dentin surfaces (n=144) and grinded with a 600 grit sandpaper. The samples were randomly divided into three main groups (N=48) based on the adhesive system and application procedures. GROUP 1: No contamination (control), GROUP 2: Blood contamination, GROUP 3: Blood Contamination+Haemostatic agent application. Each group was further divided into four subgroups: SUBGROUP I: Single Bond 2 (etch-and-rinse) Subgroup II: Clearfil SE Bond (two-step self-etch) Subgroup III: Single Bond Universal (multimode, etch-and-rinse) subgroup IV: Single Bond Universal (multimode, all-in-one self-etch) (n=12). Resin cylinders (Filtek Z550) were bonded to the dentin surfaces according to the manufacturers' instructions. A shear load was applied to the specimens using universal testing machine at a cross-head speed of 0.5 mm/min until failure. Data were analyzed statistically (p<0.05). RESULTS: Statistically significant differences were observed between no contamination (control) and blood + haemostatic agent contamination groups for both Single Bond 2 (etch-and-rinse) and Single Bond Universal (multimode, all-in-one self-etch) (p<0.05). When the adhesive systems were compared to each other, no statistically significant differences were found in all contamination groups and control group for the mean SBS values (p>0.05). CONCLUSION: When blood contamination is inevitable two step self- etching adhesive systems may be the choice of adhesive system in terms of shear bond strength.
