Nitrogen-containing bisphosphonate therapy-Part II: Assessment of alveolar bone tissue inflammatory response in rats-A blind randomized controlled trial.

This study aimed to evaluate the alveolar bone tissue inflammatory response in rats undergoing zoledronic acid therapy. The study sample was composed of 28 Wistar rats. Animals from the test group GTa received a weekly intraperitoneal dose of 0.2 mg/kg of zoledronic acid for 3 weeks, while test group GTb received the same dose for 8 weeks. A physiological saline dose, equivalent to that of the medication, was administered to the controls in groups GCa and GCb. A defect was created in the dental crown of the lower first molars using a drill to simulate pulp and periapical injury. Data were evaluated regarding image grey levels by cone-beam computed tomography and histologically by assigning scores for the presence of inflammatory infiltrate, type of infiltrate, vascularization, bone necrosis and dental resorption. Grey levels in the 3-week therapy group (GTa) showed more pronounced changes in comparison with those seen in the GCa group (P < 0.05). Evaluation of the scores demonstrated no association between any of the variables amongst the groups (>0.05). However, bone remodelling decreased in the groups receiving the medication. Bone necrosis was present more frequently in group GTb than in the control group GCb. The results suggest that the drug interfered in the reaction capacity of the alveolar bone tissue as test group GTa showed higher grey levels in comparison to the control group GCa. In addition, there was less bone remodelling activity, with the appearance of bone necrosis zones and intense acute inflammatory infiltrate associated with the 8-week therapy group GTb.

Nitrogen-containing bisphosphonate therapy: assessment of the alveolar bone structure in rats - a blind randomized controlled trial.

This study aimed to assess the effect of zoledronic acid exposure on structures of the alveolar bone of rats. The sample was composed of 42 male Wistar rats. Animals in the T1 and T2 groups received weekly doses of 0.2 mg/kg intraperitoneal zoledronic acid for 3 weeks, while animals in the T3 group received the same treatment for 8 weeks. The control groups C1, C2 and C3 received equivalent doses of saline. The first upper molars of Wistar rats in the C2, T2, C3 and T3 groups were extracted. Cone-beam computerized tomography scans were performed, and the image density was analysed by grey levels. The presence and type of inflammatory infiltrate, vascularization and bone necrosis were assigned by histological qualitative scores. Histomorphometric analysis of bone density was performed in the groups without extraction. No significant differences were found in the bone grey density estimated by grey-level value and histomorphometric analysis between the C1 and T1 groups (P > 0.05). The grey levels in the T3 group were lower (P < 0.05) than in the C3 group, corresponding to the bone defect. Histological assessments showed the presence of bone necrosis in the T3 group and lower levels of bone remodelling in the test groups (T2 and T3) compared to the control groups (C2 and C3). The results of qualitative analyses did not differ significantly between the groups (P > 0.05). Zoledronic acid-exposed animals showed maxillary changes including reduced grey levels, the presence of bone necrosis and a higher prevalence of inflammatory signs.