Enhancement of in vitro Bioactivity by Surface Treatments of Ultra-thin Titanium Foils for Guided Periodontal Tissue Regeneration

This study developed a non-biodegradable membrane from commercial ultra-thin pure titanium (cpTi) foils as a guided tissue regeneration membrane for a potential modality in periodontal therapy. The etching behavior of ultra-thin cpTi foils in 40% sulfuric acid for various etching times was studied along with the effects of surface modification on in vitro bioactivity determined as well. Based on experimental results, we recommend an etching time of at least 30 min to maximize weight loss of ultra-thin cpTi foils. Scanning electron micrographs of the acid-etched titanium surface revealed a uniform distribution of extremely minute (3-4 mu m) peaks and valleys. Additionally, machining (untreated) of the titanium surface yielded typical microscopically grooved surface features. Surface roughness increased with etching time and was closely related to weight loss. Etching for more than 30 min in 40% sulfuric acid substantially increased the X-ray diffraction (XRD) intensity of TiH2, as evidenced by the changes in weight loss and surface morphology. In vitro assessment revealed that adequate acid-etching treatments may increase in vitro titanium bioactivity in a simulated body fluid (SBF) solution and cell culture. Moreover, results of the tissue culture also established that treated (AE-Ti) ultra-thin foils promoted cell migration and repaired damaged bones more effectively than untreated (CP-Ti) ultra-thin foils. Results of this study demonstrate that etching treatment with concentrated sulfuric acid is an effective means of modifying the surfaces of ultra-thin cpTi foils and enhancing in vitro titanium bioactivity.