IADR Abstract Archives
Osteonecrosis of the Jaw Lesion in Rats - Clinical, Histological and Micro-CT Characteristics
Objectives: to establish and characterize MRONJ in a rat model in order to further investigate the pathogenesis, prevention and treatment of the disease.
Methods: Nineteen rats were randomly allocated into test or control groups. Rats in the test group were administered weekly with zolandronic acid +dexamethasone for 11 weeks. Control rats were treated with saline. Extraction of first maxillary molar was performed three weeks following first drug administration all rats. Rats were euthanized at 11 weeks. Healing of extraction socket was evaluated clinically, histologically, and by micro-CT. Clinical parameters included degree of mucosal healing and presence of exposed bone. The histomorphometrical parameters included area of osteonecrosis, number of empty lacunae and blood vessels density. The Micro-CT parameters included: bone mineral density (BMD), tissue mineral density (TMD), cortical thickness (Cort.Th,mm), bone volume/tissue volume (BV/TV), trabecular thickness (Tb.Th), trabecular number (Tb.N) and connectivity density (Conn.D, mm). These parameters were examined in extraction socket (ROI-1) and buccal cortical plate of non-extracted tooth (ROI-2)
Results: All rats survived the study. Clinical and histological characteristics of MRONJ-like lesions were observed in 50% of the rats in the test group, while all rats in the control group demonstrated normal healing. MARONJ-like lesion was characterized by discontinuation of the epithelium, exposed bone, presence of empty lacunae surrounded by inflammatory infiltrate and scarce blood vessels. Histomorphometry revealed significant differences in empty lacunae and blood vessels densities between test and control. Micro-CT showed reduction of 40-45% in BV/TV, Tb.N and Conn.D at ROI 1 and 26% increase in BV in ROI-2 in the test group compared with control.
Conclusions: MARONJ was established presenting unique clinical and histological characteristics in 50% of the rats in the test group . Moreover, Micro-CT analysis showed 40% reduction in bone volume and trabecular thickness in the test group indicating on impaired healing of the extraction socket.
Methods: Nineteen rats were randomly allocated into test or control groups. Rats in the test group were administered weekly with zolandronic acid +dexamethasone for 11 weeks. Control rats were treated with saline. Extraction of first maxillary molar was performed three weeks following first drug administration all rats. Rats were euthanized at 11 weeks. Healing of extraction socket was evaluated clinically, histologically, and by micro-CT. Clinical parameters included degree of mucosal healing and presence of exposed bone. The histomorphometrical parameters included area of osteonecrosis, number of empty lacunae and blood vessels density. The Micro-CT parameters included: bone mineral density (BMD), tissue mineral density (TMD), cortical thickness (Cort.Th,mm), bone volume/tissue volume (BV/TV), trabecular thickness (Tb.Th), trabecular number (Tb.N) and connectivity density (Conn.D, mm). These parameters were examined in extraction socket (ROI-1) and buccal cortical plate of non-extracted tooth (ROI-2)
Results: All rats survived the study. Clinical and histological characteristics of MRONJ-like lesions were observed in 50% of the rats in the test group, while all rats in the control group demonstrated normal healing. MARONJ-like lesion was characterized by discontinuation of the epithelium, exposed bone, presence of empty lacunae surrounded by inflammatory infiltrate and scarce blood vessels. Histomorphometry revealed significant differences in empty lacunae and blood vessels densities between test and control. Micro-CT showed reduction of 40-45% in BV/TV, Tb.N and Conn.D at ROI 1 and 26% increase in BV in ROI-2 in the test group compared with control.
Conclusions: MARONJ was established presenting unique clinical and histological characteristics in 50% of the rats in the test group . Moreover, Micro-CT analysis showed 40% reduction in bone volume and trabecular thickness in the test group indicating on impaired healing of the extraction socket.