Antibacterial and Remineralizing Fillers in Experimental Orthodontic Adhesives

• Main Authors: Carolina Jung Ferreira, Vicente Castelo Branco Leitune, Gabriela de Souza Balbinot, Felipe Weidenbach Degrazia, Marianna Arakelyan, Salvatore Sauro, Fabricio Mezzomo Collares
• Format: Article
• Language: English
• Published: MDPI AG 2019-02-01
• Series: Materials
• Subjects: adhesive; orthodontic; mineral deposition; anti-bacterial agents; quaternary ammonium compounds; boron nitride
• Online Access: https://www.mdpi.com/1996-1944/12/4/652

Orthodontic adhesives with antimicrobial and remineralizing properties may be an alternative to control white spot lesions around brackets. The aim of this study is to develop an experimental orthodontic adhesive containing boron nitride nanotubes (BNNT) and alkyl trimethyl ammonium bromide (ATAB). Methacrylate (BisGMA and TEGDMA) monomers were used to formulate the adhesives. Four experimental groups were produced with the addition of 0.1 wt.% BNNT (G_BNNT); 0.1 wt.% ATAB (G_ATAB); and 0.2 wt.% BNNT with ATAB (G_BNNT/ATAB); in the control group, no fillers were added (G_Ctrl). The degree of conversion, cytotoxicity, softening in solvent, contact angle and free surface energy, antibacterial activity, shear bond strength, and mineral deposition were evaluated. Adhesives achieved degree of conversion higher than 50% and cell viability higher than 90%. G_BNNT and G_ATAB adhesives exhibited reduced softening in solvent. Mean free surface energy was decreased in the G_BNNT adhesive. Significant reduction in bacterial growth was observed in the G_BNNT/ATAB. No statistical difference was found for shear bond strength. Mineral deposition was found in G_BNNT, G_ATAB, and G_BNNT/ATAB groups after 14 and 28 days. The addition of 0.2% BNNT/ATAB to an experimental orthodontic adhesive inhibited bacterial growth and induced mineral deposition without affecting the properties of the material.