Dentin surface treatment using a non‐thermal argon plasma brush for interfacial bonding improvement in composite restoration

Abstract

The objective of this study is to investigate the treatment effects of non-thermal atmospheric gas plasmas on dentin surfaces for composite restoration. Extracted unerupted human third molars were used by removing the crowns and etching the exposed dentin surfaces with 35% phosphoric acid gel. The dentin surfaces were treated by using a non-thermal atmospheric argon plasma brush for various durations. The molecular changes of the dentin surfaces were analyzed using FTIR/ATR and an increase in carbonyl groups on dentin surfaces was detected with plasma treated dentin. Adper Single Bond Plus adhesive and Filtek Z250 dental composite were applied as directed. To evaluate the dentin/composite interfacial bonding, the teeth thus prepared were sectioned into micro-bars as the specimens for tensile test. Student Newman Keuls tests showed that the bonding strength of the composite restoration to peripheral dentin was significantly increased (by 64%) after 30 s plasma treatment. However, the bonding strength to plasma treated inner dentin did not show any improvement. It was found that plasma treatment of peripheral dentin surface up to 100 s gave an increase in interfacial bonding strength, while a prolong plasma treatment of dentin surfaces, e.g., 5 min treatments, showed a decrease in interfacial bonding strength.

Nonthermal Atmospheric Plasmas in Dental Restoration

“…Regarding the modification process, EDX/XPS studies affirmed significant increase in oxygen content on NTAP-treated dental surfaces, reflecting the important role of reactive oxygen species in introducing polar, oxygen-containing groups to the substrates (Koban et al 2011;Silva et al 2011;Lehmann et al 2013;Valverde et al 2013;Chen et al 2014). XPS narrow scans suggested that NTAP treatment induced substantial increase in C-O-, O=C-O-, and CO 3 2-signals on enamel (Lehmann et al 2013), and FTIR analysis revealed an increase in the amount of carbonyl groups (1,760 cm -1 ) on demineralized dentin collagen (Ritts et al 2010).…”

Cold plasma-induced surface modification of heat-polymerized acrylic resin and prevention of early adherence of <i>Candida albicans </i>

“…Atmospheric-pressure cold plasma -a complex mixture composed of ions, energetic free radicals, electrons, atoms, and molecules generated by gas discharge-has attracted much interest in biomedicine because of its potential applicability in bacterial inactivation 13,14) , tooth whitening 15,16) , blood coagulation 17) , and cancer therapy 18) . In recent years, researchers reported that plasma could be used as an economical and effective means to modify dental materials' surfaces [19][20][21][22][23] . Previous researches confirmed that after heat-cured acrylic resin was treated with cold plasma, it increased the shear bond strength between heat-cured acrylic resin and self-curing acrylic resin 21) .…”

Efeito do plasma de oxigênio na dentina previamente exposta ao NaOCl

“…Embora seja uma tecnologia, no presente momento, de alto custo para uso em consultório, o plasma vem mostrando resultados promissores em relação a atividade antimicrobiana e adesão 6,[8][9][10][11][12][13] . O presente estudo avaliou o efeito do plasma de oxigênio na superfície dentinária, uma vez que este tratamento poderia levar a um aumento na rugosidade desta superfície e a criação de grupamentos funcionais 13,[16][17][18] , que poderiam neutralizar o efeito deletério do oxigênio nascente gerado pelo hipoclorito de sódio.…”

“…Plasmas não térmicos ou ainda plasmas atmosféricos são gases parcialmente ionizados, que contêm partículas altamente reativas, incluindo átomos eletronicamente excitados, moléculas, íons e espécies de radicais livres, cuja fase gasosa permanece próxima da temperatura ambiente 5,6 . Dependendo da composição química do plasma ou gás, estas espécies altamente reativas podem reagir com a superfície, limpando, causando uma erosão (etching), combinando-se com a mesma e formando uma fina camada de recobrimento por plasma, e, desta forma, alterar as características da superfície 6,7 .…”