Microstructured zirconia surfaces modulate osteogenic marker genes in human primary osteoblasts

Abstract

In dentistry, zirconia has been used since the early 1990s for endodontic posts, more recently for implant abutments and frameworks for fixed dental prostheses. Zirconia is biocompatible and mechanically strong enough to serve as implant material for oral implants. Although several zirconia implant systems are available, currently the scientific and clinical data for zirconia implants are not sufficient to recommend them for routine clinical use. Here the influence of microstructured yttria-stabilized zirconia (YZ) on human primary osteoblast (HOB) behavior was determined. YZ surfaces were treated by sandblasting (YZ-S), acid etching (YZ-SE) and additionally heat treatment (YZ-SEH). Morphological changes of HOB were determined by scanning electron microscopy. Actin cytoskeleton was investigated by laser scanning microscopy and analyzed by novel actin quantification software. Differentiation of HOB was determined by real time RT-PCR. Improved mechanical interlocking of primary HOB into the porous microstructure of the acid etched and additionally heat treated YZ-surfaces correlates with drastically increased osteocalcin (OCN) gene expression. In particular, OCN was considerably elevated in primary HOB after 3 days on YZ-SE (13-fold) as well as YZ-SEH (12-fold) surfaces. Shorter actin filaments without any favored orientation on YZ-SE and YZ-SEH surfaces are associated with higher roughness (Ra) values. Topographically modified yttria-stabilized zirconia is a likely material for dental implants with cell stimulating properties achieving or actually exceeding those of titanium.

Hydrofluoric acid etching of dental zirconia. Part 2: effect on flexural strength and ageing behavior

“…Among the different surface chemical treatments already proposed in the literature for this purpose, hydrofluoric acid (HF) etching appears to be a good candidate [9][10][11][12]. Besides zirconia dental implants with acid etched surface are already commercialized (CeraRoot implants with ICE™ surface) and apparently have shown a similar success rate as compared to Titanium implants after five years of follow-up study [13].…”

Surface micro‐structuring of zirconia dental implants

“…Sandblasted and acid etched as well as sandblasted, acid‐etched, and thermally treated specimens showed downregulation of alkaline phosphatase and upregulation of osteocalcin after 3 days compared with machined or sandblasted surfaces, indicating a progressive osteoblast differentiation on these surfaces (Bergemann et al. ).…”

Hydrofluoric acid etching of dental zirconia. Part 1: etching mechanism and surface characterization

“…Ito et al showed that the combination of both treatments leads to an increase in the proliferation rate and expression of ALP activity of osteoblast-like cells (MC3T3-E1) [14] and Bergemann et al. found recently that it enhanced the human primary osteoblast maturation [15].…”