Surface modification of several dental substrates by non-thermal, atmospheric plasma brush

Abstract

Objective The purpose of this study was to reveal the effectiveness of non-thermal atmospheric plasma brush in surface wettability and modification of four dental substrates. Methods Specimens of dental substrates including dentin, enamel, and two composites Filtek Z250, Filtek LS Silorane were prepared (~2 mm thick, ~10 mm diameter). The prepared surfaces were treated for 5–45 s with a non-thermal atmospheric plasma brush working at temperatures from 36 to 38 °C. The plasma-treatment effects on these surfaces were studied with contact-angle measurement, X-ray photoemission spectroscopy (XPS) and scanning electron microscopy (SEM). Results The non-thermal atmospheric argon plasma brush was very efficient in improving the surface hydrophilicity of four substrates studied. The results indicated that water contact angle values decreased considerably after only 5 s plasma treatment of all these substrates. After 30 s treatment, the values were further reduced to <5°, which was close to a value for super hydrophilic surfaces. XPS analysis indicated that the percent of elements associated with mineral in dentin/enamel or fillers in the composites increased. In addition, the percent of carbon (%C) decreased while %O increased for all four substrates. As a result, the O/C ratio increased dramatically, suggesting that new oxygen-containing polar moieties were formed on the surfaces after plasma treatment. SEM surface images indicated that no significant morphology change was induced on these dental substrates after exposure to plasmas. Significance Without affecting the bulk properties, a super-hydrophilic surface could be easily achieved by the plasma brush treatment regardless of original hydrophilicity/hydrophobicity of dental substrates tested.

Nonthermal plasma on the shear bond strength of relining resin to thermoplastic denture base resin

“…The chemical changes include the improvement of the surface wettability and forming a functional group such as hydroxyl brought to the surface after exposure to plasma. 15 In this study, although NTP alone did not showed improvement of shear bonding strength, the combination of NTP with sandblasting showed signiflcantly higher value. This is maybe due to thermoplastic resin's high degree of crystallinity, 1,9-11 the NTP alone is not enough to improve the bonding strength between TDBRs and relining resin.…”

“…3) Sandblasting (SB) 50 μm alumina particles, treatment for 15 seconds with a pressure of 0.28 MPa at a distance of 20 mm perpendicular to the treated surface. 4) Sandblasting and nonthermal plasma (SB + NTP) combined treatment of sandblasting for 15 seconds followed by nonthermal plasma for 5 minutes at a distance of 10 mm perpendicular to the treated surface.…”

“…14 The method of plasma treatment advances the surface adaptation of dental materials. 15 In the previous studies, it is reported that surface modification using plasma treatment have improved the bonding strength between heat cured acrylic resin and self-curing acrylic resin. 16,17 The purpose of this study was to evaluate the effect of nonthermal plasma treatment on the bond strength of the autopolymerizing relining resin material to thermoplastic denture base resins in comparison to different surface treatments.…”

Efeito do plasma de oxigênio na dentina previamente exposta ao NaOCl

“…O tratamento com plasma é uma tecnologia "limpa" e "eficaz", em que as propriedades internas dos materiais podem permanecer inalteradas ou preservadas após o tratamento 5 . 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 .…”

“…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 .…”