Long-term antimicrobial assessment of orthodontic brackets coated with nitrogen-doped titanium dioxide against Streptococcus mutans

• Published in: Progress in orthodontics 2018-09, Vol.19 (1), p.35-6, Article 35
• Main Authors: Salehi, Parisa, Babanouri, Neda, Roein-Peikar, Mehdi, Zare, Fatemeh
• Format: Article
• Language: English
• Subjects: Anti-Infective Agents - pharmacology; Antimicrobial activity; Antimicrobial agents; Bracket; Coated Materials, Biocompatible - chemistry; Coated Materials, Biocompatible - pharmacology; Coatings; Colony Count, Microbial; Decalcification; Dental enamel; Dentistry; Humans; Materials Testing; Medicine; Nanoparticles; Nitrogen; Orthodontic Appliance Design; Orthodontic Brackets - microbiology; Orthodontics; Photocatalytic TiO2; Stainless steel; Streptococcus infections; Streptococcus mutans; Streptococcus mutans - drug effects; Streptococcus mutans - growth & development; Surface Properties; Thin films; Time Factors; Titanium; Titanium - pharmacology; Titanium dioxide; X-Ray Diffraction
• ISSN: 2196-1042; 1723-7785; 2196-1042
• DOI: 10.1186/s40510-018-0236-y

Background The antimicrobial properties of orthodontic wire and brackets with nitrogen-doped titanium dioxide (N-doped TiO2) coating have been studied in the past. However, the evaluation period had been short and limited to 30 days. The aim of the present study was to extend the evaluation period (up to 90 days) of assessing the long-term antimicrobial effects of stainless steel orthodontic brackets coated with nitrogen-doped titanium dioxide (N-doped TiO2). Methods A total of 40 stainless steel pre-adjusted premolar brackets were equally divided into two groups; namely the control group ( n =20, uncoated brackets) and the experimental group ( n =20, coated brackets). RF magnetron sputtering was used to apply a thin film of TiO2 on the bracket surface. The crystalline structure of the thin film was assessed using X-ray diffraction. The antimicrobial property of the brackets against Streptococcus mutans ( S. mutans ) was evaluated using the survival rate by colony-forming units (CFU) at four intervals: 24 hours (T0), 30 days (T1), 60 days (T2), and 90 days (T3). 2-way ANOVA Repeated Measures was used to compare the effects between the groups over the time. Results There was no significant interaction between group and time ( p  = 0.568). The orthodontic brackets coated with the N-doped TiO2 thin film showed a significant CFU reduction (37.71 ± 5.21, 37.81 ± 5.03, 37.98 ± 5.37, and 37.74 ± 5.21 at T0, T1, T2, and T3, respectively) compared to the uncoated brackets (400.91 ± 14.67, 401.58 ± 14.01, 400.31 ± 14.68, and 402.04 ± 13.98 at T0, T1, T2, and T3, respectively) through visible light ( p