Air Atmospheric Pressure Plasma Jet Research Articles

Development of hydrophilic dental wax without surfactant using a non-thermal air atmospheric pressure plasma jet

Dental wax (DW), a low-melting and high-molecular-weight organic mixture, is widely used in dentistry for forming moulds of teeth. Hydrophilicity is an important property for DW, as a wet dental investment is used to surround the wax before wax burnout is performed. However, recent attempts to improve the hydrophilicity of DW using a surfactant have resulted in the reduced mechanical properties of the dental investment, leading to the failure of the dental restoration. This study applied a non-thermal air atmospheric pressure plasma jet (AAPPJ) for DW surface treatment and investigated its effect on both DW hydrophilicity and the dental investment's mechanical properties. The results showed that the application of the AAPPJ significantly improved the hydrophilicity of the DW, and that the results were similar to that of cleaner-treated DW using commercially available products with surfactant. A surface chemical analysis indicated that the improvement of hydrophilicity was related to an increase in the number of oxygen-related bonds on the DW surface following the removal of carbon hydrate in both AAPPJ and cleaner-treated DW. However, cleaner treatment compromised the mechanical property of the dental investment when the dental investment was in contact with the treated DW, while the AAPPJ treatment did not. Therefore, the use of AAPPJ to treat DW is a promising method for accurate dental restoration, as it induces an improvement in hydrophilicity without harming the dental investment.

The effects of enhancing the surface energy of a polystyrene plate by air atmospheric pressure plasma jet on early attachment of fibroblast under moving incubation

Enhancing the biomaterial surface energy has received wide attention as a possible option for improving cell adhesion. Non-thermal atmospheric pressure plasma jets (APPJ) have been introduced to medical fields as one of the on-site treatment methods to enhance surface energy before implantation. The aim of this study is to evaluate the effect of enhancing the surface energy of a polystyrene plate by air APPJ on the early attachment of fibroblasts under moving incubation. In addition, the range of plasma jet effect was measured for easy on-site application. After 2min of air APPJ treatment, mouse fibroblasts (L929) were separately seeded through the prepared holes on the treated polystyrene plate as well as as-received polystyrene plate. Cells were allowed to attach for 30min or 4h under 70 revolutions per minute. The surface characteristic results confirmed the increase of surface energy six times after air APPJ treatment with the Owens–Wendt method. Minimal change of surface temperature and amine functional group without roughness changes were detected. In the case of a short attachment time (30min), the attached L929 were only found on air APPJ-treated center surface. In 4h attachment time, cells were attached with vinculin focal adhesion and elongated actin filament on the both the right and left side surfaces from the center area which was treated by the plasma jet flame. In light of this study, air APPJ could be useful for early-rapid attachment of mouse fibroblasts on polystyrene plates under moving incubation. Future studies can examine its on-site use with biomaterials.