Osteonecrosis of the jaw (ONJ)

Different factors can leed to an osteonecrosis of the jaw (ONJ): irradiation, osteomyelitis and drugs. In the last two decades in particular antiresorptive drugs namely bisphosphoantes and denosumab have come into focus because the application in high and frequent dosages is associated with the manifestation of an ONJ in 2-8 %.

The pathomechanism of the medication related osteonecrosis of the jaw (MRONJ) has not been fully elucidated but both drugs are potent inhibitors of osteoclast activity. Osteoclast are very important cells for bone resorption, which is essential in case of bone infections or after tooth extraction. The inhibition of osteoclast activity then may result in an inadequate wund healing and in due course to an osteonecrosis.
Therefore, prophylaxis (removal of tooth and bone infections before initiation of the antiresorptive therapy) and prevention (removal of tooth and bone infections under a running antiresorptive therapy) are very important to avoid MRONJ.
The typical clinical hallmark for a MRONJ is exposed jaw bone without a healing tendency.
If in spite of prophylactic measures a MRONJ has developed, surgical therapy is the treatment of choice.
This is for several good reasons:
- success rates of surgical approaches are significantly higher compared to conservative treatment regimens (>85 % vs < 25%)
- exposed bone areas / MRONJ will inevitably progress in size because there is no barrier for oral microflora
- exposed bone is necrotic bone that will not be revitalized but hampers the wound healing
The modern autofluorescence technique that is routinely applied in our surgical treatment enables the surgeon in the operation to distinguish between necrotic in viable bone. Therefore, the osteonecrosis can be removed very precisely.

Please do not hesitate to contact us if you have any questions about prophylactic, preventive or therapeutical matters or needs together with ONJ.