Antimicrobial Potential of Strontium-Functionalized Titanium Against Bacteria Associated With Peri-Implantitis.

OBJECTIVES: To explore the antimicrobial potential of strontium (Sr)-functionalized wafers against multiple bacteria associated with per-implant infections, in both mono- and multispecies biofilms. MATERIALS AND METHODS: The bactericidal and bacteriostatic effect of silicon wafers functionalized with a strontium titanium oxygen coating (Sr-Ti-O) or covered only with Ti (controls) against several bacteria, either grown as a mono-species or multispecies biofilms, was assessed using a bacterial viability assay and a plate counting method. Mono-species biofilms were assessed after 2 and 24 h, while the antimicrobial effect on multispecies biofilms was assessed at Days 1, 3, and 6. The impact of Sr functionalization on the total percentage of Porphyromonas gingivalis in the multispecies biofilm, using qPCR, and gingipain activity was also assessed. RESULTS: Sr-functionalized wafers, compared to controls, were associated with statistically significant less viable cells in both mono- and multispecies tests. The number of colony forming units (CFUs) within the biofilm was significantly less in Sr-functionalized wafers, compared to control wafers, for Staphylococcus aureus at all time points of evaluation and for Escherichia coli at Day 1. Gingipain activity was less in Sr-functionalized wafers, compared to control wafers, and the qPCR showed that P. gingivalis remained below detection levels at Sr-functionalized wafers, while it consisted of 15% of the total biofilm on control wafers at Day 6. CONCLUSION: Sr functionalization displayed promising antimicrobial potential, possessing bactericidal and bacteriostatic ability against bacteria associated with peri-implantitis grown either as mono-species or mixed in a multispecies consortium with several common oral microorganisms.

Bone regenerating effect of surface-functionalized titanium implants with sustained-release characteristics of strontium in ovariectomized rats.

Since strontium (Sr) is known for its anabolic and anticatabolic effect on bone, research has been focused on its potential impact on osseointegration. The objective of this study was to investigate the performance of nanotopographic implants with a Sr-functionalized titanium (Ti) coating (Ti-Sr-O) with respect to osseointegration in osteoporotic bone. The trial was designed to examine the effect of sustained-release characteristics of Sr in poor-quality bone. Three Ti-Sr-O groups, which differed from each other in coating thickness, Sr contents, and Sr release, were examined. These were prepared by a magnetron sputtering process and compared to uncoated grade 4 Ti. Composition, morphology, and mechanical stability of the coatings were analyzed, and Sr release data were gained from in vitro washout experiments. In vivo investigation was carried out in an osteoporotic rat model and analyzed histologically, 6 weeks and 12 weeks after implantation. Median values of bone-to-implant contact and new bone formation after 6 weeks were found to be 84.7% and 54.9% (best performing Sr group) as compared to 65.2% and 23.8% (grade 4 Ti reference), respectively. The 12-week observation period revealed 84.3% and 56.5% (best performing Sr group) and 81.3% and 39.4% (grade 4 Ti reference), respectively, for the same measurements. The increase in new bone formation was found to correlate with the amount of Sr released in vitro. The results indicate that sputtered nanostructured Ti-Sr-O coatings showed sustained release of Sr and accelerate osseointegration even in poor-quality bone, and thus, may have impact on practical applications for medical implants.

Enhanced osseointegration of endosseous implants by predictable sustained release properties of strontium.

UNLABELLED: Studies have shown that strontium (Sr) incorporated into surfaces may enhance osseointegration. Thus, we suggested that a sustained Sr release from implant surfaces could improve bone healing. This study verifies and further investigates the effect of a novel Ti-Sr-O functionalized implant surface prepared from a magnetron co-sputtering platform with a continuous release of Sr. MATERIALS AND METHODS: Four experimental Ti-Sr-O groups, which differed from each other in Sr contents and pre-wash procedures, were tested. Implants were prepared with a Ti-Sr-O coating by means of magnetron co-sputtering and compared to Grade 4 titanium. Composition, morphology and mechanical stability were analyzed; Sr-release data were gained from in vitro washout experiments. In vivo investigations were carried out in a rat model and analyzed histologically regarding bone-to-implant contact and new bone formation 30 days after implantation. RESULTS: Structural differences were detected between the two basis Ti-Sr-O coatings with 6.7 at.% and 8.9 at.% Sr, respectively. Different release profiles were observed with 8.9 at.% Sr coating exhibiting the highest long-term release of Sr. Median values of new bone formation and bone-to-implant contact was found to be 60.1% and 91.6%, respectively, for the best group compared to 16.6% and 70.6% for the Grade 4 titanium reference. The increase in new bone formation was found to correlate with the amount of Sr released in vitro. CONCLUSION: The results show that sputtered Ti-Sr-O coatings with sustained release of Sr may improve osseointegration, and could thus have impact on practical applications for medical implants.