[Effect of different plasma treated zirconia on the adhensive behaviour of human gingival fibroblasts].

Objective: To evaluate the effect of different cold atmospheric plasma (CAP) treatment on the surface chemical and physical properties of zirconia and adhensive behaviour of human gingival fibroblasts (HGFs) cultured on zirconia disks.

Methods: The zirconia disks were divided into four groups and treated using helium, argon and mixture of argon and oxygen cold atmospheric plasma for 90 s or left untreated. The surface morphology, wettability and chemical elements were analyzed right after treatment. Human gingival fibroblasts were grown from biopsies obtained from a periodontally healthy human subject during periodontal surgery. HGFs were seeded on zirconia disk, and cells density was measured at the time point of 3 hours. Indirect immunofluorescence (IIF) was performed for morphometric examination at the time point of 3 hours.

Results: The crystallographic structure of zirconia was analyzed previously and the results suggested that it fitted the properties of zirconium yttrium oxide. After helium, argon and mixture of argon and oxygen cold atmospheric plasma treatment, the surface morphology and roughness of zirconia disks remained the same. The contact angle of zirconia decreased significantly(P<0.05)after CAP treatment: from 68.38° to 17.90°. After different CAP plasmas treatment, the atomic percentage of carbon on the outermost surface of the three groups decreased, as did the surface C/O ratio. The surface C/O ratio of zirconia decreased from 1.07 to 0.33. Fibroblasts density increased on CAP treated disks, especially the ones treated by mixture of argon and oxygen CAP(P<0.05). Cells of the three CAP plasma treatment groups spread better and had more protrusions, as well as larger surficial areas.

Conclusion: Based on the results of this study after being treated by different kinds of CAP plasmas for 90 s, the surface wettability increased and the elements changed significantly with no changes in the tomography and roughness of the materials. The CAP treatment enhances the adhensive behavior of fibroblasts on zirconia by increasing the oxygen functional groups and promoting the cell density. Wettability of zirconia, an important physicochemical property, has a vital influence on the cell behaviors.