Microstructured zirconia surfaces modulate osteogenic marker genes in human primary osteoblasts

Area of Science:

• Biomaterials Science
• Dental Implantology
• Cell Biology

Background:

• Zirconia has been utilized in dentistry since the 1990s for various applications, including endodontic posts and dental prostheses.
• While biocompatible and mechanically robust for oral implants, current clinical data for zirconia implants are insufficient for routine use.
• Understanding the interaction between zirconia surface topography and osteoblast behavior is crucial for developing effective dental implant materials.

Purpose of the Study:

• To investigate the influence of microstructured yttria-stabilized zirconia (YZ) surfaces on human primary osteoblast (HOB) behavior.
• To evaluate the effects of different surface treatments (sandblasting, acid etching, heat treatment) on HOB morphology, cytoskeleton, and differentiation.
• To correlate surface topography and roughness with osteoblast gene expression, particularly osteocalcin.

Main Methods:

• YZ surfaces were prepared using sandblasting (YZ-S), acid etching (YZ-SE), and combined acid etching with heat treatment (YZ-SEH).
• Human primary osteoblasts (HOBs) were cultured on these surfaces, and their morphology was assessed via scanning electron microscopy.
• Actin cytoskeleton was analyzed using laser scanning microscopy and specialized software, while HOB differentiation was quantified by real-time RT-PCR for osteocalcin gene expression.

Main Results:

• Acid-etched and heat-treated YZ surfaces (YZ-SE and YZ-SEH) demonstrated improved mechanical interlocking of HOBs.
• Significantly elevated osteocalcin (OCN) gene expression was observed in HOBs cultured on YZ-SE (13-fold) and YZ-SEH (12-fold) surfaces after 3 days.
• Shorter actin filaments without preferred orientation on YZ-SE and YZ-SEH surfaces correlated with higher surface roughness (Ra) values.

Conclusions:

• Topographically modified yttria-stabilized zirconia exhibits cell-stimulating properties beneficial for dental implant applications.
• The enhanced osteocalcin expression and altered actin cytoskeleton suggest improved osteoblast response on specifically treated YZ surfaces.
• These findings indicate that microstructured YZ has the potential to serve as a dental implant material, possibly exceeding the performance of titanium.