Histomorphometric investigation of the effect of zoledronic acid on existing experimental periodontitis

Although the effects of bisphosphonates on normal healthy bone has been extensively demonstrated in studies, the interaction of zoledronic acid and inflammation in chronic periodontal inflammation and its effect on periodontal tissues is a new field of study. In our randomized controlled single-blind in-vivo study, we aimed to investigate the effects of repeated zoledronic acid (ZA) injections on oral mucosa and inflammatory process with experimental periodontitis by micro-CT (Computed Tomography) and histological observations. Twenty 20 Sprague-Dawley rats were randomly assigned to two groups based on drug use. To facilitate plaque deposition on the upper left second molar teeth of all experimental animals, 5-0 surgical thread was placed in the gingival sulcus. The upper right second molar teeth were used as periodontal disease free controls. The presence of periodontal disease was clinically checked on the 21st day and the animals assigned to drug test group was injected with nitrogen-containing bisphosphonate (ZA) and the second group was injected with saline on days 21, 28, 35, 42, 49 and 56. All subjects included in the study were sacrificed one week after the completion of the injections and the obtained samples were subjected to micro-CT followed by histological examination. According to micro-CT results, alveolar bone loss around teeth was found to be significantly higher (p <0.05) in zoledronic acid used group and experimental periodontitis group compared to other groups. In histological evaluation results, inflammation, necrosis and epithelial proliferation were found to be significantly higher (p <0.05) in zoledronic acid group and experimental periodontitis group. The use of bisphosphonate-containing zoledronic acid had an adverse effect on alveolar bone destruction and necrosis when used without treatment of existing periodontal disease.