J Adhes Dent 20 (2018), No. 1 16. Mar. 2018
J Adhes Dent 20 (2018), No. 1 (16.03.2018)
Page 57-64, doi:10.3290/j.jad.a39880, PubMed:29457156
Effect of Calcium Hydroxide on Bonding Performance of an Experimental Self-etch Adhesive
Garcia, Marcelle Gonçalves / Poskus, Laiza Tatiana / Hass, Viviane / Amaral, Cristiane Mariote / Noronha-Filho, Jaime Dutra / Silva, Eduardo Moreira da
Purpose: To investigate the effect of Ca(OH)2 concentration on pH neutralization, degree of conversion (DC%), and bonding performance of experimental self-etch adhesives (SEAs).
Materials and Methods: Four different concentrations of Ca(OH)2 (0 wt%, 1 wt%, 2 wt%, and 4 wt%) were added to the bond of an experimental two-step SEA consisting of primer (10-MDP [30 wt%], TEG-DMA [30 wt%], ethanol [35 wt%], water [5 wt%], camphorquinone [0.5 wt%], and tertiary amine [0.5 wt%]) and bond (bis-GMA [50 wt%], TEG-DMA [30 wt%], HEMA [20 wt%], camphorquinone [0.5 wt%], and tertiary amine [0.5 wt%]) to form four groups: E0, E1, E2 and E4. pH neutralization was evaluated until it reached equilibrium, and DC% within the hybrid layer was analyzed by micro-Raman spectroscopy. Human molars were wet ground until the occlusal dentin was exposed, SEAs were applied, and composite buildups were constructed. After storage in distilled water at 37°C for 24 h, the teeth were cut into composite-dentin beams. Microtensile bond strength (µTBS) was evaluated after 24 h of water storage at 37°C. Nanoleakage was evaluated by SEM. Data were analyzed using ANOVA and Tukey's HSD test (a = 0.05).
Results: All the SEAs reached pH equilibrium after thirteen days, with E1 and E4 presenting the highest pH (p < 0.05). E0 and E1 presented lower DC% than did E2 and E4 (p < 0.05). All the SEAs showed statistically similar mTBS and nanoleakage (p > 0.05).
Conclusion: The incorporation of Ca(OH)2 endowed the SEAs with pH-neutralization ability and improved their DC%, without interfering with the bond strength to dentin or nanoleakage extent.
Keywords: self-etch adhesives, pH neutralization, calcium hydroxide, degree of conversion, bond strength, nanoleakage