IADR Abstract Archives
Sintered Fluoroapatite Coatings on Titanium; Physicochemical Properties and Degradation Profile
Objectives: Fluorapatite (FA) implant coatings have the potential to induce bone growth and possess antibacterial properties. The aim of this study was to perform detailed physicochemical surface analysis to explore the role of sintering on surface properties and degradation of FA coatings on two different titanium (cpTi) surfaces.
Methods: FA coatings were deposited onto in-house prepared cpTi discs (12mm diameter, 1mm thick), either machine cut (Ti) or sandblasted and double acid-etched (SLDA), using a mild hydrothermal method. Half of the coated discs were sintered at 800°C for 180min, to give 4 groups of 5 samples which were examined before and after sintering. Surface roughness (Sa) and thickness were analysed using a Laser Profilometry. A morphological and chemical characterisation was performed using Scanning Electron Microscopy and Energy Dispersive Spectroscopy (SEM-EDS). Water contact angle (WCA) and surface energy were calculated for all groups before and after sintering. Daily Fluoride release in Brain Heart Infusion at pH 7.0 and 4.0 was evaluated using fluoride ion selective electrode for 7 days.
Results: The hydrothermal method produced ordered FA coatings with well-aligned hexagonal crystals for all groups. FA coatings on Ti showed higher roughness (3.88µm±0.9) and thickness (9.43µm±0.7) compared to SLDA (1.62µm±0.4) and (6.85µm±0.4). Sintering significantly reduced coatings’ roughness and thickness for Ti, this was non-significant for SLDA. SEM-EDS characterisations showed slight morphological changes and Ca/P reduction after sintering and acidic aging. FA coatings on Ti and SLDA displayed low WCA 19°-12°, which decreased after sintering to 12°-6°. FA coatings, especially the sintered ones, presented higher polar (41-49mN/m) and electron donor character (46-47mN/m), in comparison to the uncoated Ti and SLDA. Daily F release in pH 4.0 ranged between 4.7-12 ppm for all groups and this was dramatically decreased (2-4.8 ppm) on the 6th day for non-sintered groups. Sintering significantly reduced acidic degradation of FA, maintaining stable coatings.
Conclusions: Detailed characterization of the FA coatings allows for better interpretation of the performance of the sintered FA coatings. Sintering is effective in bringing an enhancement in the chemical stability of the coatings.
Methods: FA coatings were deposited onto in-house prepared cpTi discs (12mm diameter, 1mm thick), either machine cut (Ti) or sandblasted and double acid-etched (SLDA), using a mild hydrothermal method. Half of the coated discs were sintered at 800°C for 180min, to give 4 groups of 5 samples which were examined before and after sintering. Surface roughness (Sa) and thickness were analysed using a Laser Profilometry. A morphological and chemical characterisation was performed using Scanning Electron Microscopy and Energy Dispersive Spectroscopy (SEM-EDS). Water contact angle (WCA) and surface energy were calculated for all groups before and after sintering. Daily Fluoride release in Brain Heart Infusion at pH 7.0 and 4.0 was evaluated using fluoride ion selective electrode for 7 days.
Results: The hydrothermal method produced ordered FA coatings with well-aligned hexagonal crystals for all groups. FA coatings on Ti showed higher roughness (3.88µm±0.9) and thickness (9.43µm±0.7) compared to SLDA (1.62µm±0.4) and (6.85µm±0.4). Sintering significantly reduced coatings’ roughness and thickness for Ti, this was non-significant for SLDA. SEM-EDS characterisations showed slight morphological changes and Ca/P reduction after sintering and acidic aging. FA coatings on Ti and SLDA displayed low WCA 19°-12°, which decreased after sintering to 12°-6°. FA coatings, especially the sintered ones, presented higher polar (41-49mN/m) and electron donor character (46-47mN/m), in comparison to the uncoated Ti and SLDA. Daily F release in pH 4.0 ranged between 4.7-12 ppm for all groups and this was dramatically decreased (2-4.8 ppm) on the 6th day for non-sintered groups. Sintering significantly reduced acidic degradation of FA, maintaining stable coatings.
Conclusions: Detailed characterization of the FA coatings allows for better interpretation of the performance of the sintered FA coatings. Sintering is effective in bringing an enhancement in the chemical stability of the coatings.