Differences in microhardness and tensile strength of stainless steel temporary anchorage devices after exposure to fluoride, povidone-iodine, and chitosan solution.

Temporary anchorage devices (TADs) are widely utilized as supplementary anchorage in orthodontic treatment, offering several advantages alongside certain limitations. One such limitation is the potential for mechanical failure, which may occur due to a reduction in corrosion resistance. Recent studies have reported changes in the mechanical properties of TADs - notably decreased corrosion resistance - following exposure to mouthwash during orthodontic treatment. The objective of this study is the evaluation of corrosion resistance of stainless steel (SS) TADs by assessing changes in microhardness and tensile strength following in vitro exposure to mouthwashes. A total of 28 TADs were categorized into four distinct groups differentiated by the type of mouthwash utilized: Fluoride, povidone-iodine, chitosan, or distilled water (control group). Each TAD was placed in a centrifuge tube and immersed in the respective solution for 90 days. Changes in the mechanical aspects of the SS TADs were evaluated through the assessments of microhardness using the Vickers method and tensile strength using a tensile test. The highest microhardness value was observed in the chitosan group (435 VHN), followed by the fluoride group (429.71 VHN), the povidone-iodine group (429.29 VHN), and the distilled water group (420 VHN). Similarly, the highest tensile strength was recorded in the chitosan group (70.20 megapascal [MPa]), followed by the fluoride group (68.87 MPa), the povidone-iodine group (67.19 MPa), and the distilled water group (48.59 MPa). SS TADs exhibited superior mechanical properties after immersion in a chitosan solution, indicating their potential protective effect against corrosion-related degradation.