The purpose of this study was to evaluate effects of titanium surfaces air-abraded with particles of Bioglass® 45S5 and three-ZnO and SrO doped compositions on the viability, adhesion and biofilm formation of Streptococcus mutans. A statistically significant decrease in the viability of S. mutans was observed for all titanium discs air-particle abraded with the BAGs (p<0.001). Also, a significant effect on diminishing biofilm formation on the titanium discs was seen for all BAGs (p<0.01). No differences were noticed in S. mutans adhesion on titanium surfaces treated with different glasses (p=0.964). Static SBF immersion experiments showed that after 2 and 48 h the BAG doped with 4 mol% ZnO demonstrated the highest Zn 2+ ion concentration released into SBF (0.2 mg L −1 ). 45S5 BAG demonstrated the highest statistically significant increase in the pH throughout the 120 min of static immersion (p<0.001). In conclusion, we showed that titanium alloy discs abraded with particles of the experimental compositions and 45S5 BAG had strong antimicrobial activity against S. mutans and they suppressed S. mutans biofilm formation. The antimicrobial activity of 45S5 BAG was attributed to high pH whereas for the Zn-containing BAGs antimicrobial activity was due to steady release of Zn 2+ into the interfacial solution.

No abstract

Streptococcus mutans is able to form a high-affinity biofilm on material surfaces. S mutans has also been detected around infected implants. Bioactive glasses (BAGs) have been shown to possess antibacterial effects against S mutans and other microorganisms. This in vitro study was performed to investigate the influence of BAG air abrasion on S mutans biofilm on sandblasted and acid-etched titanium surfaces. Sandblasted and acid-etched commercially pure titanium discs were used as substrates for bacteria (n = 107). The discs were immersed in an S mutans solution and incubated for 21 hours to form an S mutans biofilm. Twenty colonized discs were subjected to air abrasion with Bioglass 45S5 (45S5 BAG), experimental zinc oxide containing BAG (Zn4 BAG), and inert glass. After the abrasion, the discs were incubated for 5 hours in an anaerobic chamber followed by an assessment of viable S mutans cells. Surface morphology was evaluation using scanning electron microscopy (n = 12). The thrombogenicity of the glass particle–abraded discs (n = 75) was evaluated spectrophotometrically using whole-blood clotting measurement at predetermined time points. Air abrasion with 45S5 and Zn4 BAG eradicated S mutans biofilm. Significantly fewer viable S mutans cells were found on discs abraded with the 45S5 or Zn4 BAGs compared with the inert glass (P &lt; .001). No significant differences were found in thrombogenicity since blood clotting was achieved for all substrates at 40 minutes. Air abrasion with BAG particles is effective in the eradication of S mutans biofilm from sandblasted and acid-etched titanium surfaces. Zn4 and 45S5 BAGs had similar biofilm-eradicating effects, but Zn4 BAG could be more tissue friendly. In addition, the steady release of zinc ions from Zn4 may enhance bone regeneration around the titanium implant and may thus have the potential to be used in the treatment of peri-implantitis. The use of either BAGs did not enhance the speed of blood coagulation.

The aim of this study was to evaluate the hydrophilicity, surface free energy, and proliferation and viability of human osteoblast‐like MC3T3‐E1 cells on sandblasted and acid‐etched titanium surfaces after air‐abrasion with 45S5 bioactive glass, zinc‐containing bioactive glass, or inert glass. Sandblasted and acid‐etched titanium discs were subjected to air‐abrasion with 45S5 bioactive glass, experimental bioactive glass (Zn4), or inert glass. Water contact angles and surface free energy were evaluated. The surfaces were studied with preosteoblastic MC3T3‐E1 cells. Air‐abrasion with either type of glass significantly enhanced the hydrophilicity and surface free energy of the sandblasted and acid‐etched titanium discs. The MC3T3‐E1 cell number was higher for substrates air‐abraded with Zn4 bioactive glass and similar to that observed on borosilicate coverslips (controls). Confocal laser scanning microscopy images showed that MC3T3‐E1 cells did not spread as extensively on the sandblasted and acid‐etched and bioactive glass‐abraded surfaces as they did on control surfaces. However, for 45S5‐ and Zn4‐treated samples, the cells spread most at the 24 h time point and changed their morphology to more spindle‐like when cultured further. Air‐abrasion with bioactive glass and inert glass was shown to have a significant effect on the wettability and surface free energy of the surfaces under investigation. Osteoblast cell proliferation on sandblasted and acid‐etched titanium discs was enhanced by air‐abrasion with 45S5 bioactive glass and experimental Zn4 bioactive glass compared with air‐abrasion with inert glass or no air‐abrasion.

Although the initial in vitro dissolution of bioactive glasses (BAG) is well characterized, the long-term behaviour of crystallized BAG scaffolds in a continuous fluid flow is incompletely understood. A detailed understanding of the long-term dissolution of scaffolds is vital for predicting their behaviour in clinical applications. Here, we explored the dissolution and reaction mechanisms of partly crystalline and glass–ceramic scaffolds based on the bioactive glasses S53P4 and 45S5 using a continuous flow-through method in Tris-buffer (Tris) and simulated body fluid (SBF) for up to 21 days. Granules of the parent glasses were used as references. The main crystalline phase in both scaffolds was sodium-calcium-silicate. The scaffolds’ dissolution suggested that the sodium-calcium-silicate crystals dissolved incongruently to yield hydrous silica. The silica phase then provided abundant nucleation sites for hydroxyapatite precipitation, resulting in fine-grained crystalline structures. When exposed to Tris, the scaffolds almost completely dissolved within the test period, leaving only highly porous remnant phases. For the 45S5 scaffolds, the calcium phosphate reaction layers that formed on their surfaces effectively slowed the dissolution in SBF. In contrast, this effect was less apparent for the S53P4 specimens.