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Objectives: We compared the effects of fluoride mouthwashes on surface topography of orthodontic wires, and static and kinetic frictional forces between stainless-steel (SS) orthodontic brackets and SS and nickel-titanium (NiTi) archwires. Materials and Methods: This in vitro, experimental study evaluated 240 standard SS maxillary central incisor brackets and 0.018-, and 0.025×0.019-inch NiTi and SS archwires. Different combinations of wire diameters and wire types were exposed to artificial saliva (control), 0.05% sodium-fluoride (NaF) for 1 minute daily, or 0.2% NaF for 1 minute weekly (37°C) for 3 months. The wires were pulled in the bracket slots by 5mm in a universal testing machine (10mm/minute). The static and kinetic forces were measured. The surface topography of the wires was inspected under a scanning electron microscope (SEM). Three-way ANOVA followed by Bonferroni post-hoc tests were used for statistical analysis (P<0.05). Results: The mean static and kinetic frictional forces of 0.025×0.019- inch NiTi wired in the 0.05%NaF group were significantly greater than the SS wire. The mean kinetic frictional force in the 0.05%NaF group was significantly greater than the 0.2%NaF and artificial saliva groups for all wires. The mean static and kinetic forces in 0.2%NaF were significantly greater than in artificial saliva. In all groups, larger wires showed higher mean frictional forces. SEM results revealed higher wire surface roughness in the 0.05%NaF group followed by the 0.2%NaF group. Conclusion: Weekly use of 0.2%NaF mouthwash is recommended during sliding mechanics to minimize frictional forces between SS and NiTi wires and SS brackets.

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Objectives: Use of miniscrews has become very common in orthodontic treatment of patients. Following tissue manipulation during miniscrew placement, bacteremia may occur, which is important in patients susceptible to infective endocarditis. This study aimed to investigate the possibility of bacteremia following orthodontic miniscrew placement. Materials and Methods: The present quasi-experimental study was conducted on 30 orthodontic patients, including 11 males (36.7%) and 19 females (63.3%) with a mean age of 23.67±4.87 years, who required miniscrew placement in their treatment plan. Two blood samples were taken from the patients for aerobic and anaerobic cultures right before and 30-60 seconds after miniscrew placement. To investigate the presence of bacteremia, the blood samples were incubated in an automated blood culture machine for five days. The standard biological methods were used for the positive sample(s) to identify the type of bacteria. Data analysis was performed using the McNemar test. Results: The blood samples of 29 patients were negative for the bacteria before and after miniscrew placement. Blood sample of one patient was positive for aerobic and anaerobic bacteria after miniscrew placement. However, bacteremia was negative in the initial (preplacement) blood samples for both aerobes and anaerobes. Conclusion: Miniscrew placement in orthodontic patients was not associated with bacteremia.

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