Effect of Atmospheric Pressure Plasma Treatment and Surface Roughness on Osteoblastic Response and Osteoconductivity of Zirconia

Abstract

Objective. The aim of this study was to evaluate osteoblast-like cell response and bone formation associated with implantation of roughened yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) after an atmospheric pressure plasma (APP) treatment.

Materials and Methods. Disc-shaped specimens (Ø 13 × 1 mm) were prepared and divided into 4 groups depending on surface roughness and APP treatment. The disc-shaped surfaces were roughened by sandblasting followed by hydrofluoric (HF) acid etching. Surfaces were analyzed by XPS with contact angle measurement. Surface characteristics of disc samples were evaluated by SEM, CLSM and XPS analyses. The spreading of MG63 cells on the disc surfaces was observed by SEM after a 30-minute incubation period. Screw-type dental implant fixture-shaped specimens with external hex (Ø 4 × 7 mm) were prepared and divided into four groups depending on surface roughness and APP treatment. The rough fixture-shaped specimens were manufactured in a net-shaped mold with a rugged surface by the powder injection technique. Osteoconductivity tests with various surface properties were performed in the mesial region of rabbit tibiae at 4 weeks following installation. Removal torque test (RTQ) and histomorphometric analyses were performed, and data were analyzed using 2-way ANOVA (p= 0.05).

Results. APP treatment enhanced the surface hydrophilicity of Y-TZP disc- and fixture-shaped specimens without topographical changes. The spreading of MG63 cells on plasma-treated disc surfaces at 30 minutes were higher compared to untreated surfaces (p<0.001), and the APP-treated fixture-shaped specimens exhibited significantly higher BIC values than those of untreated ones (p<0.001).

Conclusion. Atmospheric pressure plasma treatments increased surface hydrophilicity of Y-TZP and enhanced the initial spread of MG63 cells as well as osseointegration in rabbits.