Atmospheric cold plasma brush treatment effects on dental composite restoration

Objectives: The purpose of this study is to investigate the plasma treatment effects on dental composite restoration for improved interface properties.

Methods: An atmospheric cold plasma brush (ACPB), a non-thermal gas plasma source, was used to treat and prepare dentin surfaces for dental adhesive and dental composite application. Extracted unerupted human third molars were used for this investigation. The occlusal one-third of the crown was sectioned by means of a water-cooled low speed diamond saw (Buehler, Lake Bluff, IL). The exposed dentin surfaces were polished with 600 grit SiC under water and 35% phosphoric acid etched for 15s (3M ESPE). Adper^TM Single Bond Plus adhesive (3M ESPE) and Filtek^TM Z250 composite (3M ESPE) were applied and light cured. Adhesive surfaces were plasma treated before the application of the composite. Dentin/composite bars (8-10 mm ×1 mm × 1 mm) were cut from the prepared teeth for tensile testing and interface characterization.

Results: Our tensile test data showed that one minute plasma treatment of the dentin surface increased the tensile strength of the dentin/adhesive interface from 27.0 ± 14.7 MPa to 38.6 ± 9.3 MPa. The fracture interface of the tested specimen was examined using scanning electron microscopy (Philips XL30 ESEM-FEG). It was found that numerous plasma treated samples failed in locations other than the dentin/adhesive interface, while most of the control samples failed at the interface.

Conclusions: Our experimental results showed that ACPB plasma treatment can modify the dentin surface and thus increase the dentin/adhesive interfacial bonding. Non-thermal atmospheric plasmas, such as the ACPB, have great potential in dental composite restoration application for improved performance.

Acknowledgement: This study was supported by US National Science Foundation (NSF).