Effects of solvent evaporation on water sorption/solubility and nanoleakage of adhesive systems

Abstract

ObjectiveTo evaluate the influence of solvent evaporation in the kinetics of water diffusion (water sorption-WS, solubility-SL, and net water uptake) and nanoleakage of adhesive systems. Material and MethodsDisk-shaped specimens (5.0 mm in diameter x 0.8 mm in thickness) were produced (N=48) using the adhesives: Clearfil S3 Bond (CS3)/Kuraray, Clearfil SE Bond - control group (CSE)/Kuraray, Optibond Solo Plus (OS)/Kerr and Scotchbond Universal Adhesive (SBU)/3M ESPE. The solvents were either evaporated for 30 s or not evaporated (N=24/per group), and then photoactivated for 80 s (550 mW/cm2). After desiccation, the specimens were weighed and stored in distilled water (N=12) or mineral oil (N=12) to evaluate the water diffusion over a 7-day period. Net water uptake (%) was also calculated as the sum of WS and SL. Data were submitted to 3-way ANOVA/Tukey's test (α=5%). The nanoleakage expression in three additional specimens per group was also evaluated after ammoniacal silver impregnation after 7 days of water storage under SEM. ResultsStatistical analysis revealed that only the factor "adhesive" was significant (p<0.05). Solvent evaporation had no influence in the WS and SL of the adhesives. CSE (control) presented significantly lower net uptake (5.4%). The nanoleakage was enhanced by the presence of solvent in the adhesives. ConclusionsAlthough the evaporation has no effect in the kinetics of water diffusion, the nanoleakage expression of the adhesives tested increases when the solvents are not evaporated.

Efeito da temperatura de evaporação do solvente na longevidade da adesão de adesivos autocondicionantes à dentina

“…Hydrophilic adhesives including the all-in-one system in the present study can attract water that plasticizes polymers, reducing their mechanical properties 20,21 . The nanoleakage was enhanced by the presence of solvent in Clearfil SE Bond and Clearfil S 3 Bond dental adhesives 22 . The type of solvent (acetone, butanol, or ethanol/water) has shown to prioritarialy affect the evaporation rate of the adhesive, despite the time needed to do it 23 .…”

Glycerol-dimethacrylate as alternative hydrophilic monomer for HEMA replacement in simplified adhesives

“…Specimens were created with standardized silicone molds and were individually light-cured by the LED unit DB85 (Dabi Atlante, Ribeirão Preto, Brazil) with 1100 mW/cm 2 irradiance 40 s. After 24 h, the specimens were placed in a desiccator device containing silica gel and stored at 37 °C under vacuum. The specimens were repeatedly weighed on an analytical balance ± 0,0001 g (Metter-Toledo AG285, São Paulo, Brazil) every 24 h, until a constant mass in which variation was less than 0.2 mg within a 24 h period (m1) was obtained (Chimeli et al, 2014). The thickness and diameter of the specimens were measured at three different points to the nearest 0.01 mm using a digital caliper, and these measurements were used to calculate the volume (V) of each specimen (in mm 3 ).…”

The effect of acrylate-based dental adhesive solvent content on microleakage in composite restorations

“…[ 4 5 ] The purpose of adding a solvent to the dental bonding agent is to dilute it to create a thin layer on the surface of etched tooth, and displacement of water from the collagenous network and penetration of resin monomers into these spaces. [ 6 7 8 ] Although the presence of the solvent in bonding agent is necessary, the entire solvent must be completely eliminated from bonding before curing the bonding agent because its presence can have adverse effects on polymerization of the resin monomers. [ 9 10 ] When the solvent's concentration is too high, reduced photoinitiator concentration and occupation of spaces between the monomer molecules will cause a reduction in the conversion of monomers to polymers and reduces the mechanical properties and strength of the bonding.…”