Effect of air-polishing on titanium surfaces, biofilm removal and biocompatibility

Methods: A total of 57 titanium discs (7.5mm x 2.0mm, Southern Implant, Irene, South Africa; ASTM-F67-95 grade 4 pure titanium) were randomly allocated into six treatment groups. Streptococcus mutans biofilms were grown on discs in brain-heart infusion broth for three days. Discs were treated with AIR-N-GO PERIO (Acteon, France) using glycine powder (PERIO AIR-N-GO Powder, Acteon, France) for 5 s and then rinsed for 20 s with an air-water syringe. Scanning electron micrographs were taken before and after the treatment. A crystal violet assay was performed to quantify the reduction in bacterial biofilms. Biocompatibility was evaluated by measuring the viability of L929 fibroblast cells grown on titanium discs.

Results:  Air-polishing for 5 s reduced the amount of biofilm 8.6-fold compared to the untreated controls (P<0.05, Mann-Whitney test) and the reduction was visible under SEM. Coverage of air-polished and rinsed discs by fibroblasts was half that of untreated discs (20.4% and 41.0% respectively, P<0.05, ANOVA). Sterile, air-polished discs, without rinsing, had the lowest fibroblast coverage (5.07%). Less than 1% of the area of air-polished and rinsed discs was covered with dead cells, whilst discs that were only air-polished showed no dead fibroblasts. 

Conclusions:  Air-polishing with a specialized periodontal tip removed a significant amount of biofilm from titanium surfaces. It appears that the ‘polishing’ reduced the biocompatibility of the disc surface. The reduced fibroblast cell growth on disc surfaces could have been caused by the presence of glycine powder, and this requires further investigation. 

Acknowledgements: Financial support from Acteon, Satelec, France