Evaluation of Antimicrobial Performance of Calcium Dihydroxide (Ca(OH)2) Coating on Ti for Potential Metallic Orthopedic Implant Applications

Background/Objectives: Orthopedic implant infections are rare but represent a significant problem for patients, surgeons, and the healthcare systems. This is because these infections cause severe and persistent pain and, in some cases, may require revision of the implant, among other things. Thus, there is strong interest in the use of antimicrobial coatings on orthopedic implants. Here, we investigate electrochemically deposited Ca(OH)2 antimicrobial coating for its potential to be used on metallic orthopedic implants. Methods: A triphenyl tetrazolim chloride (TTC) assay and isothermal microcalorimetry (IMC) were used to determine the reduction in microbial activity on three sets of Ti parts (discs and screws): uncoated, coated with hydroxyapatite (HA), and coated with Ca(OH)2. Results: Using the TTC assay, a ~70% reduction in the growth of bacteria on Ca(OH)2-coated discs was found, and using IMC, bacterial growth on these discs showed a decreased rate and an increased lag phase up to 25 h. Each of these sets of results was statistically superior to the corresponding results obtained using the other sets of parts. Conclusions: The present results suggest that the Ca(OH)2 coating may have potential for use on metallic orthopedic implants.