Surface structuring of zirconia to increase fibroblast viability

Current zirconia implant surfaces are either machined, polished, or heat-treated. Prior research has shown that surface topography influences cell behavior. However, the specific effects of zirconia surface treatments on fibroblast viability remain unclear. No prior work had resolved how different surface structures impact cell attachment and spread. This gap motivated a detailed investigation into zirconia surface modifications. Existing studies have not fully addressed the role of crystalline structure in cell viability. The neck area of implants requires surfaces that support cellular activity. Understanding how surface roughness and phase composition affect fibroblasts is essential for implant design. This paper contributes by examining multiple surface treatments and their biological outcomes.

The study aimed to evaluate how zirconia surface topography and crystalline structure influence human gingival fibroblast viability. Researchers focused on comparing polished, heat-treated, and sandblasted surfaces. They wanted to determine which surface characteristics promote optimal cell behavior. The motivation came from the need to improve implant integration through better surface design. The goal was to identify surfaces that allow fibroblasts to spread and attach effectively. The team tested surfaces with varying roughness and phase compositions. They sought to link surface properties with cell morphology and viability. This approach aimed to guide future implant surface engineering strategies.

Zirconia discs were prepared with five surface treatments: polished, polished and heat-treated, machined, machined and heat-treated, and sandblasted, etched, and heat-treated. Scanning electron microscopy analyzed surface morphology. The monoclinic to tetragonal phase ratio was measured to assess crystalline structure. Roughness and wettability were quantified using contact angle measurements. Cell viability and morphology were assessed after 24 hours of HGF-1 cell culture. Heat-treatment effects were visualized using SEM on polished specimens. Storage effects on wettability were tracked over two weeks. The study compared cell behavior across all surface types to identify optimal substrates.

Contact angle measurements showed a significant decrease in wettability after two weeks of air storage. Smooth surfaces (Zpt, Zm, Zmt) supported higher cell viability than the etched Z14 surface. HGF-1 cells spread flat and adhered tightly to smooth surfaces. On Z14, cells stretched over longer distances and did not fully extend. SEM imaging revealed that heat treatment altered surface morphology. The monoclinic to tetragonal phase ratio varied across surfaces. Roughness measurements confirmed differences in surface texture. These findings suggest that smooth surfaces with exposed grains are optimal for fibroblast viability.

The study found that smooth zirconia surfaces with exposed grains support higher fibroblast viability than etched surfaces. Cell morphology was significantly affected by surface roughness and structure. The monoclinic to tetragonal phase ratio influenced cell behavior. Wettability decreased with prolonged air storage, affecting cell attachment. The authors suggest that smooth surfaces may be preferable for implant neck areas. Their findings align with prior work on cell-surface interactions. No prior work had resolved the specific role of surface smoothness in fibroblast viability. These results may guide future implant surface design strategies.