Increased bone apposition on a titanium oxide surface incorporating phosphate and strontium

Current implant surfaces struggle to optimize osseointegration in both dense and porous bone regions. While titanium implants are widely used, their integration can be limited by surface properties. Researchers have explored modifying titanium surfaces with bioactive ions to improve bone contact. However, the specific impact of phosphate and strontium ions on bone apposition remains unclear. Prior studies have focused on calcium and phosphate alone, but the addition of strontium introduces new variables. The role of surface roughness and chemistry in promoting bone growth is well-documented, but how these factors interact with ion incorporation is less understood. This gap motivated the investigation into how phosphate and strontium ions affect implant performance. The need for surfaces that support bone growth in both cortical and cancellous environments remains unmet.

The goal of this research was to assess how a titanium implant surface modified with phosphate and strontium ions influences bone integration. The study aimed to determine whether these ions, when incorporated via hydrothermal treatment, can enhance osseointegration. A specific problem addressed was the limited understanding of how strontium affects bone apposition on titanium surfaces. The motivation stemmed from the need for implants that perform well in both dense and spongy bone regions. The research focused on comparing the new surface to a standard micro-arc oxidized surface. The objective was to evaluate the impact of surface chemistry and topography on bone contact. The study sought to provide evidence for improved integration in both cortical and cancellous bone. The findings could guide future implant surface design strategies.

The study used hydrothermal treatment to create a titanium surface with phosphate and strontium ions. Scanning electron microscopy analyzed surface morphology. X-ray diffractometry and photoelectron spectroscopy assessed chemical composition. Optical profilometry measured surface roughness. Forty implants were placed in rabbit tibiae and femoral condyles. Two groups were compared: P/Sr-modified implants and micro-arc oxidized controls. Histomorphometric analysis evaluated bone contact after four weeks. The study focused on cortical and cancellous bone regions. Surface roughness and wettability were key parameters measured.

The P/Sr implants showed moderate surface roughness with lower R(a) values than controls. Histological analysis revealed increased direct bone apposition on P/Sr surfaces. Bone-to-implant contact percentages were significantly higher for P/Sr implants in tibiae (P<0.01). Similar results were observed in femoral condyles (P<0.01). The surface chemistry included phosphate and strontium ions, which may influence bone growth. The micro-topography of P/Sr implants supported better integration. Wettability measurements suggested improved surface properties. These findings suggest that the modified surface enhances osseointegration.

The results suggest that P/Sr-modified titanium surfaces may improve osseointegration in both cortical and cancellous bone. The combination of micro-topography, P/Sr chemistry, and wettability likely contributes to better bone apposition. The study supports the potential of hydrothermally treated surfaces for biomedical implants. The findings are specific to rabbit models and four-week implantation periods. No claims about long-term performance or clinical applications are made. The authors propose that the surface modifications enhance integration through physical and chemical factors. The study does not suggest that P/Sr is essential for integration but highlights its potential benefit. The results align with the hypothesis that surface chemistry and topography influence bone contact.