Effect of Clinically Relevant CAD/CAM Zirconia Polishing on Gingival Fibroblast Proliferation and Focal Adhesions

Abstract

Mucosal seal formation around dental abutments is critical to the successful integration of dental implants into the human oral cavity. No information exists for how clinically relevant polishing procedures for computer-aided design and computer-aided manufactured (CAD/CAM) zirconia abutments affects cellular responses important to mucosal seal formation. CAD/CAM zirconia was divided into four groups for clinically relevant polishing utilizing commercial polishing heads: control, coarse, coarse plus medium, and coarse plus medium plus fine. Surfaces were analyzed with scanning electron microscopy (SEM), atomic force microscopy (AFM), and optical profilometry (OP). Subsequently, human gingival fibroblasts (HGFs) were seeded onto the zirconia surfaces. Proliferation was measured via a quantitative SEM technique and focal adhesion kinase (FAK) phosphorylation status was measured by an enzyme-linked immunosorbent assay (ELISA). Results showed an increase in proliferation on all polished surfaces as compared to the control. Phosphorylation of FAK at tyrosine 397 (Y397) was up-modulated on the control surfaces. The associated cell adaptation is discussed. In all cases, FAK phosphorylation was greater at 24 h than 48 h. These results suggest that clinicians should be mindful of the effects of abutment polishing methodology, as this may have an impact on early mucosal seal formation.

Comparison of Cytomorphometry and Early Cell Response of Human Gingival Fibroblast (HGFs) between Zirconium and New Zirconia-Reinforced Lithium Silicate Ceramics (ZLS)

“…Cells grown on a rough surface stabilize themselves on topographic irregularities, not needing to develop a strong cytoskeleton. Fibroblasts grown on smoother surfaces in order to mechanically stabilize develop a strong network of actin fibers, appearing more elongated and spread [ 40 , 42 , 43 ]. This explains why the fibroblasts grown on Y-TZP showed a greater extension of the actin filaments and an elongated shape.…”

“…There is no consensus about which is the best surface to create a good mucosal seal and reduce bacterial adhesion. Some authors have reported the importance of this surface being smooth [ 8 , 11 , 39 , 42 ], while other authors have shown that rough surfaces are preferred, either through some surface treatment like sandblasting—with random cell growth—[ 7 , 45 ], or the creation of micro-roughness [ 5 ] to enhance attachment, proliferation, and spreading in the direction of the microgrooves.…”

“…Fischer et al and Kournetas et al postulate that it is necessary to rethink the way in which roughness parameters are applied to in vitro studies. The arithmetic roughness value Ra is a limited factor in complex topographies and is a parameter that depends on experimental conditions and the surface treatment technique employed [ 42 , 46 ].…”

“…As mentioned above, there are several factors that influence initial cellular adhesion to a surface, such as chemical composition, mechanical properties (such as wettability or stiffness), or the cytotoxicity of the material. Therefore, this is a multiparametric and complex analysis, in which each parameter should be studied independently under an ISO standard, so that in vitro studies could be reproducible with objectively comparable results [ 32 , 42 , 46 ]. Some examples are ISO 10993:2009 (Part 5 based on vitro cytotoxicity tests, Part 12 based on sample preparation, and Part 19 based on physico-chemical, morphological, and topographical characterization of materials).…”

Mechanical and Thermal Properties of Dental Composites Cured with CAD/CAM Assisted Solid-State Laser

“…Accordingly, the effect of solid-state lasers on temperature rise and mechanical properties was analysed in the current research. Furthermore, we also adopted a novel approach as a standardised method for curing of dental restorative composites using CAD (computer-aided design)/CAM (computer-aided manufacturing) systems [ 32 , 33 , 34 ] equipped with LCUs.…”