Bisphosphonate-associated osteonecrosis of the jaw

Bisphosphonate -associated osteonecrosis, Eng. bisphosphonate -associated osteonecrosis of the jaw ( bonj ONJ ) are necrosis of the jaw bone, which occur more frequently in patients who were previously treated with bisphosphonates. The trigger is a dental or dental surgery in general. However, there are also described spontaneous bonj. Bisphosphonates inhibit bone resorption and are used for osteoporosis and bone metastases compared.

These are the infected osteoradionecrosis of the jaw ( IORN ) in patients after radiotherapy of head and neck cancers similar. They sometimes show severe courses. Patients with malignancy or immunosuppression are more frequently affected than osteoporosis patients. The bonj is associated almost exclusively with intravenous amino- bisphosphonates.

Bisphosphonates

Bisphosphonates are analogues of pyrophosphate, which is a substitution of oxygen with carbon in the POP binding occurs. This will take place no enzymatic hydrolysis in the body. Bisphosphonates have a high affinity to the bone surface, and in particular in the area of ​​resorption lacunae. They inhibit osteoclasts and thus lead to reduced bone resorption. In the presence of increased bone degradation rate by osteoporotic remodeling or bone metastases can be achieved through the use of bisphosphonates is a very effective reduction of osteoclastic processes. Here bisphosphonates act as a mechanical barrier between the bone surface and osteoclast. Further, there is an increased rate of apoptosis of the osteoclasts. Bisphosphonates cause such an effective inhibition of progressive bone loss. Addition occurs - probably via the normal osteoblast activity - usually a certain increase in bone density of approximately 2 to 3% per year, at least during the first three years of treatment.

Bisphosphonates have a very long pharmacological half-life in bone, which lies partly in over ten years and leads to the indication for use of this drug should be strictly provided. Currently, this group of active substances approved for the treatment of patients with overt bone metastases in tumor diseases or with postmenopausal osteoporosis.

Pathogenesis of Kiefernekrose

The bone necrosis in patients with systemic bisphosphonate therapy underlying factors are still largely unknown. Discussed is the mechanism of osteoclastic and osteoblastic inhibition that may lead not only to a reduced Osteolyserate but by osteoblasts depression also damages the regenerative capacity of the bone.

Provision

Before prescribing a therapy with intravenous bisphosphonates, a dentist should be consulted who plans and executes necessary treatment measures before the Bisphosphontatherapie. The dental restoration must not be performed in the radical extent, as is the case in patients with head and neck tumors prior to irradiation. This is also due to the absence of the risk of radiation caries. Not worth preserving teeth, root fragments and teilretinierte wisdom teeth should be removed, however. Clinically and radiologically asymptomatic root-treated teeth can be kept under annual radiological control. Teeth with chronic apical periodontitis and radicular cysts are better removed because the risk of failure is after root resection. Not to be underestimated is the possibility of a prosthesis caused by pressure points bonj; Patients with removable dentures should therefore be checked regularly.

Are in patients under continuous bisphosphonate therapy surgical intervention is required, this is done under antibiotic screening and careful as possible ( atraumatic ) approach. The indication for tooth extraction must be very strictly set. Extraction sockets are covered with plastic epiperiostal prepared Weichgewebslappen. Earlier than ten days after the intervention, the suture removal. Up to this day the antibiotics must be done. Full bony impacted wisdom teeth are left. Of interventions in terms of surgical tooth preservation is in sight. Intensive caries and periodontal prophylaxis is also recommended in these patients. According to routine follow-up, particularly in carriers of removable dentures. Implant insertions are strictly contraindicated in patients in this group.