Sorption, solubility and cytotoxicity of novel antibacterial nanofilled dental adhesive resins

Dental adhesives hydrolyze in the mouth. This study investigated the water sorption (SOR), solubility (SOL) and cytotoxicity (CYTO) of experimental adhesives containing nitrogen-doped titanium dioxide nanoparticles (N_TiO2). Specimens (n=15/group [SOR, SOL]; n=10/group [CYTO]) of unaltered Clearfil SE Protect (CSP), OptiBond Solo Plus (OSP), Adper Scotchbond (ASB) and experimental adhesives (OSP+25% or 30% of N_TiO2) were fabricated, desiccated (37 degrees C) and tested for SOR and SOL according to ISO Specification 4049 (2009). CYTO specimens were UV-sterilized (8 J/cm(2)) and monomer extracted in growth medium (1, 3 or 7 days). Human pulp cells were isolated and seeded (0.5x10(4)) for MTT assay. SOR and SOL data was analyzed using GLM and SNK (alpha =0.05) and CYTO data was analyzed with Kruskal-Wallis and SNK tests (alpha =0.05). SOR and SOL values ranged from 25.80 mu g/mm(3) (30% N_TiO2) to 28.01 mu g/mm(3) (OSP) and 23.88 mu g/mm(3) (30% N_TiO2) to 25.39 mu g/mm(3) (25% N_TiO2). CYTO results indicated that pulp cells exposed to experimental materials displayed comparable viabilities (p>0.05) to those of OSP. Experimental materials displayed comparable SOR, SOL and CYTO values (p>0.05) when compared to unaltered materials. N_TiO2 incorporation have not adversely impacted SOR, SOL and CYTO properties of unaltered adhesives.