Surface modification of orthodontic brackets with photocatalytic TiO(2) can be used to prevent the accumulation of dental plaque and the development of dental caries during orthodontic treatment.

BackgroundThe purpose of the study is to assess the antiadherent and antibacterial properties of surface-modified stainless steel and NiTi orthodontic wires with silver against Lactobacillus acidophilus.MethodsThis study was done on 80 specimens of stainless steel and NiTi orthodontic wires. The specimens were divided into eight test groups. Each group consisted of 10 specimens. Groups containing uncoated wires acted as a control group for their respective experimental group containing coated wires. Surface modification of wires was carried out by the thermal vacuum evaporation method with silver. Wires were then subjected to microbiological tests for assessment of the antiadherent and antibacterial properties of silver coating against L. acidophilus. Mann–Whitney U test was used to analyze the colony-forming units (CFUs) in control and test groups; and Student’s t test (two-tailed, dependent) was used to find the significance of study parameters on a continuous scale within each group.ResultsOrthodontic wires coated with silver showed an antiadherent effect against L. acidophilus compared with uncoated wires. Uncoated stainless steel and NiTi wires respectively showed 35.4 and 20.5 % increase in weight which was statistically significant (P < 0.001), whereas surface-modified wires showed only 4.08 and 4.4 % increase in weight (statistically insignificant P > 0.001). The groups containing surface-modified wires showed statistically significant decrease in the survival rate of L. acidophilus expressed as CFU and as log of colony count when compared to groups containing uncoated wires. It was 836.60 ± 48.97 CFU in the case of uncoated stainless steel whereas it was 220.90 ± 30.73 CFU for silver-modified stainless steel, 748.90 ± 35.64 CFU for uncoated NiTi, and 203.20 ± 41.94 CFU for surface-modified NiTi.ConclusionsSurface modification of orthodontic wires with silver can be used to prevent the accumulation of dental plaque and the development of dental caries during orthodontic treatment.

Aim: To evaluate and compare the shear bond strength of metal brackets bonded to ceramic surfaces using different conditioning methods and to assess the site of bond failure after debonding. Materials and methods:A total of 70 ceramic surfaces were produced with uniform shape, size and composition. The samples were divided into 7 groups (each of 10 samples).Group 1 was the control group (untreated surface); in group 2 the surface were roughened with a diamond bur; in group 3 the surface were etched with hydrofluoric acid; in group 4 the surfaces were sandblasted; in group 5 the surfaces roughened with bur and silane applied; in group 6 the surfaces were etched with hydrofluoric acid and silane applied and in group 7 the surfaces were sandblasted and silane applied.To all the above groups, metal orthodontic brackets were bonded with light cure adhesive. The brackets were later stored in artificial saliva and incubated at 37°C (24 hours). The samples were then subjected to shear bond strength test using an Instron universal testing machine. The debonded porcelain surfaces were then studied under stereomicroscope to assess site of bond failure.Results: Sandblasting the ceramic surface and silane application showed the highest bond strength. Stereomicroscope examination after debonding showed that the bond failure is at bracket-adhesive interface in four groups namely hydrofluoric acid, sandblasting, hydrofluoric acid with silane and sandblasting with silane. Conclusion:Sandblasting with silane combination produced the highest shear bond strength, so it is a clinically suitable method for bonding orthodontic metal brackets onto ceramic surface.Clinical relevance: Bonding orthodontic brackets to ceramic crowns of patients has been a tough task. In this study, different conditioning methods were used to treat the ceramic surfaces before bonding. The results showed that sandblasting the ceramic surface prior to application of silane produced the highest shear bond strength which is clinically suitable to reduce bond failures.

Objective: To assess the antiadherent and antibacterial pro perties of surface-modified stainless steel and nickel titanium orthodontic wires with photocatalytic titanium oxide against Streptococcus mutans (S. mutans). Materials and methods:This study was done on 80 specimens of orthodontic wires each of 5 cm in length. The specimens were divided into eight test groups, four groups were used for anti adherent test, and other four groups were used for antibacterial test. Each group consisted of 10 specimens. The groups contain ing uncoated stainless steel and uncoated nickel titanium wires acted as control group for their respective experimental group, containing coated stainless steel and nickel titanium wires. Surface modification of both stainless steel and nickel titanium orthodontic wires with photocatalytic titanium oxide was carried out by sol gel thin film dip coating method. Orthodontic wires were then subjected to microbiological tests for assessment of the antiadherent and antibacterial properties of photocatalytic titanium oxide coating against S. mutans.Results: Photocatalytic TiO 2 coating on the wires prevented the adhesion of S. mutans to the orthodontic wires, hence demonstrating antiadherent property against S. mutans. Also, photocatalytic TiO 2 coating on the surface of orthodontic wires demonstrated antibacterial effect against S. mutans. Conclusion:Surface modification of orthodontic wires with photocatalytic titanium oxide was found to have antiadherent and antibacterial properties against S. mutans.

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