Apatite-forming ability of sandblasted and acid-etched titanium surfaces modified by ultraviolet irradiation: An in vitro study

Introduction: Contamination of large grit sandblasting and acid-etching (SLA) with hydrocarbons make the surface hydrophobic and influence its bioactivity. Preservation in dH(2)O (modified SLA, modSLA) and ultraviolet (UV) irradiation were proven to be effective in decreasing hydrocarbon contamination and keeping the SLA surface hydrophilic. Aims: The aim of this study was to detect the in vitro bioactivity of SLA, modSLA and UV-SLA surfaces. Design: The SBF model was used to compare the bone-like apatite forming ability. Setting: The experiment was conducted at Southern Medical University. Materials and methods: The quantity of apatite was assessed by SEM and weighed on an electronic balance. The elemental composition and crystal phase were assessed by EDS and XRD analysis, respectively. Results: The sediments that completely covered the modSLA and UV-SLA surfaces after 4 weeks of soaking reached 3.23 +/- 0.35 mg and 2.13 +/- 0.95 mg, respectively. They were eight- and five-fold than that on the SLA surface (0.43 +/- 0.15 mg) with statistical significance (p < 0.05 and p < 0.01, respectively). EDS and XRD tests recognized the sediments on the modSLA and UV-SLA surfaces as apatite with similar elemental compositions, Ca/P ratios and crystal phases. Discussion: Hydrophilicity and abundant hydroxyl groups drive modSLA and UV-SLA surfaces to absorb more Ca2+ to accelerate the formation of apatite. Conclusion: SLA preservation in dH(2)O and UV irradiation were recognized as trustworthy methods to acquire greater bioactivity of the SLA surface.