In vitro bioactivity of laser surface-treated Ti6Al4V alloy

The effects of lasing parameters on the precipitation of hydroxyapatite (HA) on the commercial Ti6Al4V alloy in simulated body fluid (SBF) were investigated. Ti6Al4V plates were polished and ultrasonically cleaned in acetone and ethyl alcohol, respectively. The specimen surfaces were treated with Er:YAG laser using super short pulse (SSP, 50 μs) and very short pulse (VSP, 100 μs) modes. Surface roughness was measured before and after laser treatment. The specimens were immersed in simulated body fluid (SBF) for 1, 3, and 7 days and, then the amount of Ca and P precipitation on specimens was determined using SEM/EDS analysis. An average roughness varying between 0.19 and 0.81 μm in surface roughness was detected in all laser-treated specimens depending on the lasing parameters. The highest surface roughness and Ca precipitation were found in VSP group (20 Hz and 5 W). Laser treatment of specimen surfaces has dramatically increased the HA precipitation due to the increasing surface roughness. It is also concluded that the immersion time was effective on the HA precipitation as well.