Effects of TiO2-Coated Stainless Steel Orthodontic Wires on Streptococcus mutans Bacteria: A Clinical Study

Abstract

Vahid Mollabashi,1 Abbas Farmany,2 Mohammad Yousef Alikhani,3 Mohammad Sattari,4 Ali Reza Soltanian,5 Parnian Kahvand,6 Ziba Banisafar7 1Orthodontic Department, Dental Faculty and Dental Research Center, Hamadan University of Medical Sciences, Hamadan, Iran; 2Dental Research Center, Hamadan University of Medical Sciences, Hamadan, Iran; 3Department of Microbiology, Hamadan University of Medical Sciences, Hamadan, Iran; 4Division of Microstructure Physics, Department of Physics, Chalmers University of Technology, Gothenburg SE-412 96, Sweden; 5Modeling of Noncommunicable Diseases Research Center, Department of Biostatistics and Epidemiology, School of Public Health, Hamadan University of Medical Sciences, Hamadan, Iran; 6Orthodontic Department, Dental Faculty, Hamadan University of Medical Sciences, Hamadan, Iran; 7Orthodontic Department, Dental Faculty, Hamadan University of Medical Sciences, Hamadan, IranCorrespondence: Ziba Banisafar OrthodonticDepartment, Dental Faculty, Hamadan University of Medical Sciences, Hamadan, IranEmail [email protected]: The aim of this study was to clinically evaluate Streptococcus mutans adhesion on titanium dioxide–coated stainless steel orthodontic wires to decrease white-spot formation.Methods: In this study, four groups of 17 patients each (n=68) aged 12– 25 years participated. A titanium dioxide coating layer was deposited on 0.4572 mm stainless steel orthodontic wires using physical vapor deposition. The coated wires were randomly assigned to one jaw, and the opposite jaw received an uncoated wire as control. Patients were divided into groups according to the duration that wires were in their mouths: A) 1 week, B) 2 weeks, C) 3 weeks, and D) 4 weeks. Block randomization was used to assign patients to each group. At the end of the experiment, 20 mm of each wire (canine-to-canine area) was cut and cultured in S. mutans–specific medium. The culture plates were placed in an incubator containing 5% CO2 for 72 hours at 37°C, and then colonies were counted. MTT was used to test the biocompatibility of the coated and uncoated wires. To evaluate the stability of the coated titanium dioxide layer on the wires, titanium concentration on the saliva was determined using inductively coupled plasma mass spectroscopy.Results: The Kruskal–Wallis test showed that there was no significant difference in colony counts among the coated wires during 1– 4 weeks (p< 0.48). In the uncoated-wire groups, colonys count at week 1 were higher than weeks 24 –(p< 0.022). Wilcoxon’s test showed that the number of colonies was significantly different in groups A and C, but there was no significant difference in groups B or D. MTT-assay results showed that there was not a significant difference between cell viability in the coated-wire group and the control. The Kruskal–Wallis test showed that there was no significant difference in titanium concentration in the studied groups (p< 0.834).Conclusion: Application of titanium dioxide coating is effective in reducing bacterial adhesion at wire insertion.Keywords: orthodontic wire, titanium dioxide, Streptococcus mutans, bacterial adhesion

Keywords

• orthodontic wire
• titanium dioxide
• streptococcus mutans
• bacterial adhesion