Osteonecrosis of the jaw is the necrosis and exposure of a bone area caused by prolonged antiresorptive therapy. Pathology is a drug-induced complication that occurs during treatment with bisphosphonates, monoclonal antibodies-correctors of bone metabolism. The condition is manifested by loosening of teeth, exposure of the jaw bone, severe pain and difficulties when eating. Radiography and CT of the jaw, histological examination of bone biopsies are used for diagnosis. Treatment includes antibiotic therapy, surgical resection of the affected areas of the bone, experimental methods.
K10.2 Inflammatory diseases of the jaws
Osteonecrosis of the jaw is a relatively rare disease that affects 1-2% of people with prolonged therapy with bisphosphonates and other drugs against the destruction of bone tissue. Some authors believe that against the background of prolonged bisphosphonate therapy, the prevalence of the disease reaches 8-27%. The risk of developing pathology directly correlates with the type, dose and duration of medication. More frequent use of potentially toxic drugs and an increase in cases of polypragmasia increase the relevance of osteonecrosis of the jaw, require dentists and surgeons to develop adequate treatment programs.
The key etiological factor of osteonecrosis is taking medications that affect the metabolism of cartilage and bone tissue. This group includes bisphosphonates (BP) – the main drugs that are used for myeloma, bone metastases of malignant tumors, severe variants of osteoporosis. Less often, the cause is recombinant medications based on monoclonal antibodies that inhibit the activity of osteoclasts.
The likelihood of developing drug complications increases with prolonged treatment with the above-mentioned drugs. Menopausal women and the elderly are at risk, who are much more likely to face progressive osteoporosis and receive appropriate medications. The trigger of pathological changes in the bones of the jaw may be the following factors:
- Dental manipulations. Tooth extraction, implantation of pins, placement of crowns trigger necrosis of the jaw. The risk increases if the patient does not inform the dentist about taking BP, which is why the doctor cannot choose more gentle treatment options or postpone planned intervention.
- Improper oral hygiene. Any injury to the jaws increases the risk of osteonecrosis. Regular use of hard brushes, careless brushing of teeth, the use of dental floss and toothpicks leads to the development of the disease.
- Infections of the oral cavity. Paradontal pathogens play a significant role in the initiation and progression of osteonecrosis: Porphyromonas, Prevotella, Actinomyces and others. A certain importance in the progression of inflammation is assigned to staphylococci, streptococci, saprophytic neyserria.
- Concomitant diseases. The probability of osteonecrosis of the jaw increases in the presence of anemia, thrombocytopenia, coagulopathy, infectious diseases. All these conditions are typical for cancer patients receiving bisphosphonate therapy, so often one person has several risk factors.
The development of osteonecrosis of the jaw is associated with the accumulation of bisphosphonates in the bone tissue, antiangiogenic effect and direct action of drugs on the oral mucosa. The increased penetration of drugs into the jaw is due to the anatomical and physiological features of this zone: the presence of intensive remodeling processes, acidification of the environment during meals, physiological mobility of teeth.
Against the background of CF therapy and concomitant bacterial damage, the process of tissue remodeling is disrupted, which together with vascular damage leads to the impossibility of resorption of necrotized areas. At the same time, the connection of the mucous membrane with the alveolar process is disrupted, keratinocyte apoptosis is observed, collagen production is inhibited. The defeat of the mucous membrane creates conditions for the penetration of pathogens and the development of secondary osteomyelitis.
According to the clinical course, there are 4 consecutive stages of the disease. At the zero stage, there are no signs of necrotic changes in the jaw, only nonspecific periodontal symptoms are determined. Patients complain of shakiness and pathological mobility of teeth, discomfort during meals. In rare cases, a fistula is formed on the surface of the gum.
At the first stage of the disease, a partially exposed jaw bone or a deep fistula that reaches the bone surface is determined. Focal radiological changes are possible within the alveolar process. The transition of osteonecrosis to the second clinical stage occurs at the moment when the infection joins the existing areas of destruction of the jaw. There are excruciating pains, difficulty eating.
In the absence of treatment for several years, the third stage of osteonecrosis develops. It is manifested by bone exposure, chronic bacterial inflammation, involvement of tissues beyond the boundaries of the alveolar process of the jaw. Pathological fractures at the site of bone destruction, extraoral fistula passages, total osteolysis, which extends to the base of the bone, are possible.
Osteonecrosis of the jaw at stages 2-3 is a serious problem for the patient’s daily life. A strong pain syndrome in combination with a bare bone makes habitual nutrition impossible, so a person is forced to follow a special diet and use enteral mixtures. Foci of inflammation are fraught with the spread of microorganisms and purulent-destructive processes in the bones of the skull. Another problem is the inability to fully treat affected teeth.
The patient is examined by a dentist with the involvement of the attending physician, who prescribed bisphosphonate therapy for the underlying disease. Of great importance in the diagnosis is the collection of anamnesis, finding out the prescription of the appearance of symptoms and its connection with the beginning of treatment with antiresorptive drugs. After the initial examination, an extended research program is assigned, which includes the following methods:
- Jaw x-ray. X–ray examination is the basic method of diagnosing patients with suspected osteonecrosis of the jaw. Visual changes in bone tissue include reactive periosteal osteogenesis, compaction of the hard plate of the alveoli, thickening of the bottom of the maxillary sinus. With the help of radiography, foci of bone destruction are also determined.
- MSCT of the jaw. At the initial stages of the process, “empty” bone wells, foci of destruction of the jaw, a decrease in the size of the periodontal gap are revealed. The late stage of osteonecrosis is characterized by a large-scale focus of destruction that extends beyond the boundaries of the alveolar part of the jaw bone. Occasionally, pathological fractures of the jaw are determined.
- Morphological examination. Histological diagnosis of a bone tissue sample is prescribed to all patients in order to exclude the metastatic oncological process. The study determines necrosis of bone fragments with signs of chronic inflammation and bacterial colonies.
The criteria of the American Association of Dental and Maxillofacial Surgeons (AAOMS) are used for diagnosis. It includes 3 main points: therapy with antiresorptive drugs, areas of sequestered bone tissue for 8 weeks or more, the absence of cancer metastases in the jaw. During the examination, osteomyelitis, periodontitis, cement-ossifying dysplasia are excluded.
The use of BP and other types of antiresorptive therapy has more advantages compared to possible complications. Therefore, refusal to take drugs is irrational in cases when they successfully work with the underlying disease and show a stable therapeutic effect. The efforts of doctors are aimed at minimizing the side effects of bisphosphonate therapy, dynamic monitoring of patients for the prevention and timely detection of signs of osteonecrosis of the jaw.
Drug therapy includes the use of local antibiotics and antiseptics for the oral cavity. Such treatment destroys periodontal pathogens, reduces the activity of the inflammatory process and slows down the destruction of the jaw. Given the reduced immunity of most patients and the immunosuppressive effect of antibiotic therapy, it is mandatory to cover up with antifungal drugs.
With extensive foci of osteonecrosis and sequestration, isolated conservative therapy will not be effective. To remove the affected tissues, sequestrectomy and jaw resection operations are performed within healthy tissues. The traumatism of the operation itself and the course of the rehabilitation period present great difficulties for patients. In the future, reconstructive plastic surgery is performed to restore the bone defect.
The search and development of more effective and less traumatic treatment methods is constantly being carried out. The medical literature describes isolated cases of photodynamic therapy for the destruction of bacteria, bone marrow stem cell transplantation, and the use of autologous platelet concentrate. Positive results of fluorescent surgery and endoscopic interventions are reported.
Prognosis and prevention
Despite the various methods of treatment of osteonecrosis, in most patients it is not possible to achieve a stable clinical effect. Pain, destructive focus and related nutritional restrictions are observed in most patients. Effective prevention of drug-induced necrosis is dental screening before starting antiresorptive therapy, complete sanitation of the oral cavity and tooth extraction, if necessary.