Mechanical properties and modeling of drug release from chlorhexidine-containing etch-and-rinse adhesives

AbstractObjectives luate the effects of chlorhexidine (CHX) addition in different concentrations into simplified etch-and-rinse adhesives on the ultimate tensile strength (UTS), water sorption (WS), solubility (SO) and the rate of CHX release over time. s ed CHX diacetate to Ambar [AM] (FGM) and XP Bond [XP] (Dentsply) in concentrations of 0, 0.01, 0.05, 0.1 and 0.2 wt%. For UTS (n = 10 for each group), adhesive specimens were constructed in an hourglass shape metallic matrix with cross-sectional area of 0.8 mm2. Half of specimens were tested after 24 h and the other half after 28 days of water storage in tension of 0.5 mm/min. For WS and SO (n = 10 for each group), adhesive discs (5.8 mm × 1.0 mm) were prepared into a mold. After desiccation, we weighed and stored the cured adhesive specimens in distilled water for evaluation of the WS, SO and the cumulative release of CHX over a 28-day period. For CHX release (n = 10 for each group), spectrophotometric measurements of storage solution were performed to examine the release kinetics of CHX. We subjected data from each test to ANOVA and Tukey’ test (α = 0.05). s d adhesive showed significantly more WS and SO and lower UTS than Ambar. In general, the addition of CHX did not alter WS, SO and UTS of the adhesives. XP showed a higher CHX release than AM (p < 0.05) in all concentrations and the final amount of CHX release was directly proportional to the initial CHX concentration added to the adhesives. After 28 days of water storage, approximately 20% of CHX was released from XP and 8.0–12.0% from AM. sions on of CHX to commercial adhesive is a feasible method to provide a controlled release of CHX over time without jeopardizing WS, SO and UTS of the adhesives. icance cturers should consider adding CHX to commercial adhesives to provide a controlled release of CHX over time.