Desenvolvimento e avaliação de adesivo odontológico inovador contendo cloreto de 3-n propilpiridínio silsesquioxano

Abstract

Advances in knowledge of the mechanisms involved in the adhesion of resinous materials to the dental substrate need a constant development of new products. The risk of recurrence of caries may be increased by residual bacteria under restoration, a fact that remains a challenge in dentistry. The aim of the present study was to investigate the benefits of incorporating 3-n propylpyridinium silsesquioxane chloride (SiPy+Cl- ) and its molecule functionalized with copper ions ([Cu(SiPy+Cl- )2] 2+) in a universal adhesive system. The structural characterization of the compounds was performed by spectroscopy in the Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR). The in vitro susceptibility tests of SiPy+Cl and [Cu(SiPy+Cl- )2] 2+ were investigated by agar disc diffusion test and cell viability were performed using an [3-(4,5-dimetiltiazol-2yl)- 2,5-difenil tetrazolium] colorimetric assay (MTT). Experimental adhesives with 0.5, 1.0 and 2.0% of SiPy+Cl and [Cu(SiPy+Cl- )2] 2+ were developed. The influence of the incorporation of compounds into the adhesive system was determined by the degree of conversion, using micro-Raman spectroscopy, and the ultimate tensile strength, using the universal test system - Instrom. The antimicrobial activity of experimental adhesives was tested against Streptococus mutans, Escherichia coli, Staphilococus aureus and Candida albicans. Teeth obtained from the Human Teeth Bank of the Universidade Estadual de Ponta Grossa were used for the application of adhesive systems to dentin and in situ evaluation of the degree of conversion by micro-Raman spectroscopy. Subsequently, the teeth were submitted to the microtensile bond strength test, verification of fracture patterns at the adhesive interface and evaluation of nanoleakage by scanning electron microscopy (SEM). The software Graphpad Prism 5.0 was used for the statistical analysis. An antimicrobial activity and reduced cytotoxicity of SiPy+Cl- were confirmed. There was no evidence of phase separation in the developed systems and there was no damage to their mechanical characteristics. The antimicrobial activity of the adhesives at all concentrations tested was confirmed.