Osteonecrosis of the mandible is also called avascular necrosis of the jaw, and it is a rare complication of bisphosphonates. It is characterized with pain, swelling, exposure of bone, local infection and pathologic fractures of the jaw. With the widespread usage of bisphosphonates in bone metastasis of malignant tumors and osteoporosis, this rare complication has received more attention in recent years. Here, we reported a case of bisphosphonates-related osteonecrosis of the jaw (BRONJ) caused by intravenous zoledronic acid for osteoporosis. A 62-year-old female patient with 7-year history of Sjögren's syndrome and 3-year history of osteoporosis developed BRONJ after 3-year treatment of zoledronic acid. Two months before she went to the Peking University International Hospital, she visited the dentist for periodontal purulent secretion and extracted one tooth from the right mandible. However, the condition was not improved and she felt persistent pain and swelling in the right mandible. Hence, she received repeated root curettage, but there was no improvement. Finally, she was diagnosed with osteonecrosis of the mandible based on the digital volume tomography scan, which showed right mandibular osteonecrosis bone destruction. She underwent surgical debridement of the necrotic bone and administered intravenous antibio-tics at the Peking University International Hospital. Histopathological analysis of the bone biopsy further confirmed the diagnosis of BRONJ. Her condition was improved successfully during a 3-year follow-up. Osteonecrosis of the mandible become more common with the increased use of bisphosphonates. Recent study has reported that osteonecrosis of the mandible is more likely to occur in patients with Sjögren's syndrome. In addition, age, long-term and irregular administration of glucocorticoids, irregular oral examination and treatment also might be the risk factors in the pathogenesis of osteonecrosis of the mandible. For the elder osteoporosis patients who would receive or had received bisphosphonate-related drugs, oral health status and the disease states associated with necrosis of the mandible such as Sjögren's syndrome should be comprehensively measured and fully evaluated during the whole process. Furthermore, to better understand and prevent or reduce the occurrence of this complication, we reviewed the patho-genesis, diagnosis, treatment, and prevention of BRONJ.
Humans ; Female ; Middle Aged ; Bisphosphonate-Associated Osteonecrosis of the Jaw/etiology* ; Diphosphonates/administration & dosage* ; Zoledronic Acid ; Imidazoles/administration & dosage* ; Bone Density Conservation Agents/adverse effects* ; Osteoporosis/drug therapy*

Objective:To evaluate the effects of Er,Cr:YSGG laser on the root surface of periodontally involved teeth and healthy teeth,concerning the microstructure and the roughness.Methods:Eight freshly extracted teeth due to severe periodontitis and eight freshly extracted teeth due to orthodontic rea-sons or being third molar were chosen in this study.The root surface of each tooth was divided into four areas,and received four treatment methods:no treatment (control group );root planing with Gracey scaler for 30 seconds;irradiation by the lower power Er,Cr:YSGG laser;irradiation by the higher power Er,Cr:YSGG laser.Four periodontally involved teeth and four healthy teeth were used for the evaluation of microstructure using scanning electron microscope (SEM).The other four periodontitis teeth and four healthy teeth were used for the evaluation of roughness (Ra value )using 3 D profiler.Results:Smear layer was found on the teeth scaled by Gracey scaler,while the teeth irradiated by Er,Cr:YSGG laser demonstrated a melting surface with less smear layer.In the periodontitis teeth irradiated by the higher power,opening dentinal tubules could be observed.For the periodontally involved teeth,the Ra values of groups 1 to 4 were (237.4 ±20.0)nm,(1 35.7 ±1 1 .9)nm (P=0.01 ),(463.6 ±49.3)nm (P<0.001 )and (486.0 ±59.0)nm (P<0.001 )respectively.For the healthy teeth,the Ra values of groups 1 to 4 were (1 91 .4 ±44.5)nm,(1 31 .6 ±21 .5)nm (P=0.482),(463.7 ±34.6)nm (P<0.001 )and (470.3 ±1 21 .3)nm (P<0.001 )respectively.Conclusion:Er,Cr:YSGG laser can affect the microstructure of the cementum of the periodontitis teeth and healthy teeth.Irradiation by the Er,Cr:YSGG laser resulted in a melting surface with less smear layer and increased the roughness in the surface of root.