Clinical, Histological and Histomorphometric Evaluation of Effects of Silver Ion Coating of Orthodontic Fixed Retainers on Gingival Health in Rabbits

Many orthodontists believe that the only way to maintain perfect alignment after treatment is some form of permanent retention. Considering the antibacterial properties of silver ions, this in vivo study aimed to investigate the effects of silver ion coating of orthodontic fixed retainers on gingival health in rabbits. In this experimental study 24 adult male New Zealand rabbits, weighing approximately 1.8 3 kg at 9 months of age, were examined. Twenty-four pairs of maxillary teeth in these rabbits were randomly divided into 4 groups (n=6): group 1: twist wire without silver ion coating (control); group 2: twist wire with silver ion coating; group 3: prefabricated fixed retainers without silver ion coating (control); and group 4: prefabricated fixed retainers with silver ion coating. Then the samples were evaluated in terms of clinical, histological, histomorphometrical and free ions. Data were analyzed with SPSS. There were statistically significant differences between the four groups in terms of the amount and frequency of lymphocytic infiltration and capillaries (P=0.001). However, there were no statistically significant differences in the thickness of parakeratinized epithelium between the four study groups (P=0.09). The release of silver ions into artificial saliva during the first 24 hours did not exceed the limit set by WHO. In the surrounding area, fixer retainers coated with silver ions were resistant to bacterial growth and reduced gingival inflammation.