engleski

Dentin Bond Strength of Experimental Composites Containing Bioactive Glass

Objectives To investigate the bond strength of novel bioactive composites capable of precipitating hydroxyapatite on their surface. Methods Five light-curable composites were prepared by blending a Bis-GMA/TEGDMA comonomer with 45S5 bioactive glass (BG), barium glass and silica. Total filler load was 70wt% and the ratio of BG was varied from 0-40wt%. The commercial composite Beautifil Bulk Flowable (Shofu) was used as a reference. Mid-coronal dentin slabs (n=360) were obtained from intact third molars, embedded in a cold-cure acrylic resin, wet ground with P600 SiC paper and randomly divided into 6 groups (n=60 per material). Composite cylinders (d=3mm, h=4mm) were bonded on the dentin slabs with a two-step self-etch bonding agent (Clearfil SE Bond 2, Kuraray). After aqueous storage at 37°C for 1 week, 1 month and 3 months, n=20 specimens per material and storage time were randomly withdrawn for shear bond strength testing at the crosshead speed of 0.5mm/min. Bond strength data were analyzed using the two-way ANOVA, Pearson correlation and Weibull statistics. Results Material composition had a higher influence on bond strength (partial η2=0.817, p<0.001) than storage time (partial η2=0.054, p<0.001), with a significant interaction of both factors (p<0.001). Increasing the amount of BG decreased the bond strength in a linear manner (Pearson’s R: 0.996, 0.994 and 0.955, for 1 week, 1 month and 3 months respectively, p<0.01). Material reliability represented by the Weibull modulus decreased with higher amount of BG, but increased with aging. Only the composites with BG loading of 20wt% or more showed a decline in bond strength with aging. The failure mode was mostly mixed (61.7%) or adhesive (36.9%), with a low number of cohesive (1.4%) and no pre-failures. Conclusions Experimental composites with up to 10wt% of BG showed acceptable bond strength that did not deteriorate during aging up to 3 months.

bond strenght, bioactive composites, bioactive glass

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