Biosilicate as a dentin pretreatment for total-etch and self-etch adhesives: In vitro study

Purpose: To evaluate the effect of dentin pre-treatment using biosilicate microparticle suspension prior to the application of total-etch and self-etch adhesives on dentin microtensile bond strength. Material and methods: The labial enamel of forty bovine central incisors was removed using 600-grit SiC disks to expose the flat dentin surface. Six bonding protocols were evaluated (n=10): Group 1 (etching with 35% phosphoric acid+adhesive Adper Single Bond (TM) 2 Control group); Group 2 (10% biosilicate suspension prior to etching with 35% phosphoric acid+adhesive Adper Single Bond (TM) 2); Group 3 (10% biosilicate suspension after etching with 35% phosphoric acid + adhesive Adper Single Bond 2); Group 4 (self-etch adhesive Adper Easy One (TM) Control group); Group 5 (10% biosilicate suspension prior to the self-etch adhesive Adper Easy One (TM)); Group 6 (10% biosilicate suspension after the self-etch adhesive Adper Easy One (TM)). Composite build-ups were performed with Filtek (TM) Z350. The specimens were stored in distilled water for 24 h at 37 degrees C and sectioned into sticks with a 1.0 mm(2) cross-sectional area. Each stick was tested in a Universal testing machine (0.5 mm/min), and the mean microtensile bond strength data (MPa) were analyzed by two-way ANOVA and Bonferroni's multiple comparisons test (alpha=0.05). Representative SEM micrographs were taken to compare the microstructure of different treatments of dentin. The relative amounts of calcium (Ca) and phosphorus (P) were determined by EDS. Results: Group 3 (10% biosilicate suspension after acid etching with 35% phosphoric acid+adhesive Adper Single BondTM 2) showed the highest bonding values (p < 0.05). Regarding the self-etch adhesive, there was no difference (p > 0.05) between Group 5 and Group 6. SEM images demonstrated biosilicate microparticles in groups 2 and 4. EDS data analysis showed higher amounts of Ca and P ions in groups treated with biosilicate than control groups. Conclusion: The application of biosilicate microparticle suspension as dentin pre-treatment positively influenced the bond strength of the total-etch adhesive when used after acid etching; meanwhile, it does not interfere with the bonding ability of self-etch adhesive to dentin. (C) 2016 Elsevier Ltd. All rights reserved. (AU)