Dentin Bonding Agent Volatility in Relation to Shear Bond Strength

Objectives: Compare evaporation/mass loss of bonding agents (BA) as a function of time, and determine the impact of mass loss on micro-shear bond strength (MSBS) of dentin bonding.
Methods: BAs evaluated: 3 simplified (AdheSE Universal, Optibond Solo Plus, Scotchbond Universal); 1 non-simplified (Clearfil SE2).
Massing BA: 4 BAs (n=5) dispensed and massed using a digital scale (Ohaus Pioneer PA64) at 10-minute intervals: immediate, 10, 20, 30 minutes (66.7°F, 55% RH). Statistical analysis: ANOVA repeated measures with Fisher’s Test.
MSBS Test: Followed ISO 29022, 192 human third-molar specimens mounted and surfaces prepared. Specimens randomly divided into 20 groups (n=12), utilizing 4 BAs at 4 time intervals. Time intervals: BA dispensed and immediately used, dispensed and waited 10, 20, 30 minutes before use. BAs applied per manufacturer instructions to dentin of each specimen. Bonding jigs used for composite bonding (Filtek Supreme Ultra). High-powered LED for curing processes (Bluephase G2). Specimens stored in 0.2M physiologic phosphate buffered solution for 24hrs then tested until failure using a testing jig on universal testing machine (1mm/min). Statistical analysis: Kruskal-Wallis with Dunn’s test.
Results: There was significant mass loss of 3 simplified BAs and Clearfill primer. No significant change in MSBS noted for individual BA across dispense times. Optibond’s MSBS was significantly less compared to other BAs.
Conclusions: Within limitations of this study, significant loss of BA mass occurred after just 10 minutes in room air for 3 simplified BAs and Clearfill primer; loss of mass did not negatively affect MSBS.