Orthodontic resin containing bioactive glass: Preparation, physicochemical characterization, antimicrobial activity, bioactivity and bonding to enamel

Abstract

ObjectivesTo synthesize experimental orthodontic resins used for bracket bonding containing different concentrations of niobophosphate (NbG) and 45S5 glasses. MethodsExperimental resins (Bis-GMA + UDMA + DMAEMA) were developed with two bioactive glasses (NbG and 45S5) in concentrations of 5, 10 and 20 (wt%). An experimental resin without glass and a commercial resin (Transbond XT) were used. Control of pH and ions release (calcium and phosphate) at different pH values (4 and 7) were evaluated in the time intervals of 24 h, 7 d, 14 d and 28 d. Microhardness, bioactivity (SEM, FTIR/ATR) and antibacterial activity of the resins were analyzed. Metal brackets were bonded to premolars (n = 10) with the resins to evaluate shear bond strength (SBS). ResultsThe experimental resins containing 45S5 were capable of raising the pH of the solution and showed high values of calcium and phosphate ions release. Resins containing NbG had a neutralizing potential. The NbG and Transbond resins released only phosphate ions. Transbond XT showed high microhardness values when compared with the experimental 45S5 resins (p < 0.05). Analysis by SEM showed precipitates and FTIR/ATR confirmed the presence of a calcium phosphate-based compound in the resins containing 45S5. There was no difference in SBS between the tested materials (p > 0,05). The resins with presence of bioactive particles showed antibacterial activity. ConclusionWithout compromising the shear bond strength, bioactive glasses showed the capacity to elevate pH, reduce the hardness of experimental resins when compared with Transbond XT and no filler experimental resin.