Physicochemical properties and biological effects of quaternary ammonium methacrylates in an experimental adhesive resin for bonding orthodontic brackets

Authors

  • Tatiana Féres Assad-Loss Universidade Federal Fluminense, Programa de pós-graduação em Odontologia, Niterói, RJ http://orcid.org/0000-0001-7457-8735
  • Jamille Ferreira Vignoli Universidade Federal Fluminense, Programa de pós-graduação em Odontologia, Niterói, RJ
  • Isadora Martini Garcia Universidade Federal do Rio Grande do Sul, Laboratório de Materiais Dentários, Porto Alegre, RS http://orcid.org/0000-0002-7388-0200
  • Maristela Barbosa Portela Universidade Federal Fluminense, Programa de pós-graduação em Odontologia, Niterói, RJ http://orcid.org/0000-0001-5290-3744
  • Luis Felipe J. Schneider Universidade Federal Fluminense, Programa de pós-graduação em Odontologia, Niterói, RJ
  • Fabrício Mezzomo Collares Universidade Federal do Rio Grande, Pós-Graduação em Odontologia da do Sul, Porto Alegre, RS http://orcid.org/0000-0002-1382-0150
  • Larissa Maria Assad Cavalcante Universidade Federal Fluminense, Programa de pós-graduação em Odontologia, Niterói, RJ
  • Monica de Almeida Tostes Universidade Federal do Rio Grande, Pós-Graduação em Odontologia da do Sul, Porto Alegre, RS http://orcid.org/0000-0002-6878-7482

DOI:

https://doi.org/10.1590/1678-7757-2020-1031

Keywords:

Orthodontics, Dental Bonding, Dental caries, Quaternary Ammonium Compounds, Light-Curing of Dental Adhesives

Abstract

Fixed orthodontic appliances may lead to biofilm accumulation around them that may increase caries risk. This study aimed to evaluate the influence of quaternary ammonium methacrylates (QAMs) on the physicochemical properties, cytotoxicity, and antibacterial activity of adhesive resins for orthodontic purposes. Methodology: A base resin was prepared with a comonomer blend and photoinitiator/co-initiator system. Two different QAMs were added to the base adhesive: dimethylaminododecyl methacrylate at 5 wt.% (DMADDM) or dimethylaminohexadecyl methacrylate (DMAHDM) at 10 wt.%. The base adhesive, without QAMs, (GC) and the commercial Transbond™ XT Primer 3M (GT) were used as control. The resins were tested immediately and after six months of aging in the water regarding the antibacterial activity and shear bond strength (SBS). The antibacterial activity was tested against Streptococcus mutans via metabolic activity assay (MTT test). The groups were also tested for the degree of conversion (DC) and cytotoxicity against keratinocytes. Results:
The resins containing QAM showed antibacterial activity compared to the commercial material by immediately reducing the metabolic activity by about 60%. However, the antibacterial activity decreased after aging (p<0.05). None of the groups presented any differences for SBS (p>0.05) and DC (p>0.05). The incorporation of DMADDM and DMAHDM significantly reduced the keratinocyte viability compared to the GT and GC groups (p<0.05). Conclusion: Both adhesives with QAMs showed a significant reduction in bacterial metabolic activity, but this effect decreased after water aging. Lower cell viability was observed for the group with the longer alkyl chain-QAM, without significant differences for the bonding ability and degree of conversion. The addition of QAMs in adhesives may affect the keratinocytes viability, and the aging effects maybe decrease the bacterial activity of QAM-doped materials.

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Published

2021-07-05

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Original Articles