engleski

Surface roughness and mechanical properties of the archwires after intraoral aging and additional fluoridation

Aims: To explore influence of the intraoral exposure and additional fluoride application on the mechanical and surface properties of orthodontic wires. Materials and Methods: Uncoated nickel-titanium (uNiTi), rhodium-coated (RhNiTi), nitrified (NNiTi) and stainless steel (SS) archwires in dimensions 0.020 x 0.020 inch were placed for 6 weeks (42±7 days) in patients with ongoing orthodontic treatment (MBT 0.022 prescription) using the split mouth model. One group of patients were instructed to perform regular oral hygiene, another received additional remedy with high fluoride content to use once a week for five minutes. Negative controls were as-received wires ; every group had six specimens of each wire type and exposure. Wires were analysed and obtained data on: arithmetic average surface roughness Ra, root mean square roughness Rq and maximum height RZ via atomic force microscopy ; nanoindentation hardness (HIT) and Young’s modulus (EIT). The ANOVA and Students-Newman-Keuls post-hoc tests were used ; effect size was assessed by η2. The SPSS 22 (SPSS, Chicago, IL, USA) was used for all analysis, statistical significance was pre-set to p<0.05. Results: There were significant differences between the unexposed and the intraorally aged uNiTi and RhNiTi in HIT and EIT ; exposure to either regular oral hygiene or additional fluoridation did not cause significant differences. Surface roughness parameters were unaffected by intraoral aging. Conclusions: Intraoral exposure with either regular oral hygiene or additional fluoridation causes increased hardness and stiffness of the uNiTi and RhNiTi wires, while the NNiTi and the SS wires remain unaffected. Surface roughness parameters of all wires do not change significantly, regardless of oral exposure or additional fluoridation.

surface roughness ; mechanical properties ; fluoridation

HRZZ IP-2014-09-7500