Osteonecrosis of the jaw is characterized by formation of sequestrum which is a fragment of avital bone separated from adjacent sound bone as a result of focal bone necrosis which is usually associated with ischemia (1). In most cases, known local and systemic factors associated with jaw osteonecrosis are present. Osteonecrosis of the jaws might be systemically induced i.e. due to radiation treatment of head and neck cancers, due to bisphosphonate therapy (either for osteoporosis or treatment of malignancies such as multiple myeloma, etc.) (2), due to corticosteroid therapy, cocaine abuse, clotting disorders and intake of drugs which affect clotting mechanisms. Other factors might include diabetes, leukemia, Paget’s disease of bone, fibrous dysplasia, malnutrition and heavy metal poisoning (3). Necrosis of the jaws might have local causes such as previous trauma caused by dental treatment (extraction of third molars, placement of rubber dam or injuries due to use of chemicals in dentistry, etc.), bulimia or self-inflicted lesions in persons with psycological disturbances (4-6). Khullar et al. (7) reported on the sixty cases of extreme osteonecrosis and osteomyelitis of the mandible and maxilla caused by coagulopathies and osteopetrosis, Gorham's disease, infective conditions (tuberculosis, herpes zoster, HIV and osteomyelitis), toxicity (bisphosphonates, spider bites) and environmental effects such as phossy jaw, radium jaw. Over the last 7 years, the occurrence of osteonecrosis due to different and rare causes has increasingly been reported on PubMed.
Therefore, we present an unusual case of osteonecrosis due to the pulpal-peridontal syndrome and a subsequent pulp necrosis.
The patient presented in this case report has signed the informed consent approved by the Ethics Commitee of the School of Dental Medicine, University of Zagreb.
A 38-year-old female patient presented with exposed necrotic bone area on the lingual side of the right lower third molar with a diameter of 8mm. The patient was otherwise healthy and was not taking any medications. The patient denied local trauma, dental treatments in the past three months, bulimia or self-inflicted causes of the lesion. The patient had never been prescribed any byphosphonates, corticosteroids and had never been exposed to irradiation.
A complete blood count was within normal ranges. The orthopantomograph was normal without any pathological changes in the right molar area of the lower jaw (Figure 1). The CBCT showed a deep periodontal pocket between second and third molar, indicating chronic inflammatory process (Figure 2). An exophytic bone island, 8 mm in diameter, and a bone sequestrum were found on the lingual cortical plate (Figures 3 and 4).
Low level laser therapy and plasmatherapy of the lesion were not effective. Therefore, adhesive periodontal cellulose dressing (ResoPac, Hager&Werken, Duisburg, Germany) and bethamethasone oitnment inorabase which is composed of gelatin, pectin and sodium carboxymethylcellulose in plasticised hydrocarbon gel (Orabase, ConvaTec) were applied for the following three days. However, both treatments were without any improvements. The patient was subsequently prescribed peroral antibiotic amoxycillin during the period of one week, again without anyy improvement. Therefore, surgical treatment was performed. Two ampoules of articaine (Ubistesin™, 3M ESPE, Diegem, Belgium) were used for regional nerve block anesthesia. After sulcular incision and elevation of the mucoperiosteal flap, a free bone sequestrum was removed using haemostat. The remaining exophitic bone was removed using surgical hammer and chisel. Final modelation of the bone surface was performed using round steel surgical bur. Since there was a periodontal pocket (7 mm measured with periodontal probe) between lower right second and third molar, the third molar was surgically removed. A swab was taken from this area for microbiological analysis. Granulation tissue around postextracted socket was mechanically removed. The bone and granulation tissue removed during the surgical procedure were prepared for histopathological analysis. After application of the photosenzitizer, antimicrobial photodynamic therapy (aPDT) was performed using low power diode laser (LaserHF, Hager&Werken, Duisburg, Germany), in order to reduce the microbiota at the surgical site. Silk sutures with round needle (Mersilk 4.0, Ethicon, Scotland) were used. The area of the previously exposed bone was also sutured. The whole surgical area was finally covered with resorbable intraoral bandage (ResoPac, Hager&Werken, Duisburg, Germany). A microbial swab of the wound aspirate did not reveal polymorphonuclears or the presence of microorganisms. The microbial swab of the biopsy specimen of the necrotic bone particle and sequestrum showed plenty of gram-positive coccae, however, polymorphonuclears were not found. The wound swab revealed no microrganisms or polymorphonuclears.
Histopathological analysis revealed chronic inflammation (Figure 5. a, b and c). A newly formed loose connective tissue was found in the bone fragment on the other part of the bone sample (close to the postextraction socket). Abundant granulation tissue permeated with mixed inflammatory infiltration, with huge amount of histiocytes, mononuclear cells and eosinophils and with some granulocytes (Figure 5. a, b and c). The sutures were removed eight days after surgery. The patient did not report any postsurgical complications during the healing period, or subjective clinical signs and symptoms. Clinical examination revealed complete epithelisation of the wound and area of the previously necrotic alveolar bone (Figure 6.).
Traditionally, osteonecrosis of the jaw has been usually correlated with irradiation of patients due to head and neck malignancies and biphosphonate intake either for treatment of osteoporosis or malignant diseases such as multiple myeloma. Usually, factors that lead to jaw osteonecrosis are known, however, there have been few case reports in the literature where no known factors for the development of osteonecrosis could be identified. The misuse of various chemicals in dentistry such as acid etchants, arsenic paste as well as paraformaldehyde containing pastes during endodontic treatment may cause damage to the gingiva and alveolar bone (5, 6). Some dental techniques such as intraosseous anesthesia and prolonged rotation of the perforator drills in the bone might also lead to bone necrosis (8). Other medical procedures such as laryngoscopy and endotracheal tube placement might also induce osteonecrosis (9). Jackson and Malden (2) reported three cases of lingual mucosal ulceration with mandibular sequestration, two of which occurred after extraction of mandibular teeth and the third occured possibly after bisphosphonate therapy. Magremanne et al. (10) reported a case of a patient who was referred to the hospital for several tooth extractions which ended with spontaneous loss of voluminous bone fragment. The same authors concluded that avascular mandibular necrosis in their case was due to the blood coagulation disorder. As suggested by Megremanne et al., necrosis of the jaw is rarely due to bacterial, viral or fungal infection although few case reports on osteonecrosis have been described after herpes zoster infection. Apart from bisphosphonates, other medications have been identified as a possible cause of jaw osteonecrosis. Recently, Fleissig et al. (11) described a case of osteonecrosis in a 58 year old woman in the area of the right mandibular molar which had been extracted eight months before the treatment. The patient had been treated with sunitinib (antiangiogenic drug) for renal cell carcinoma. In addition to that, the patient was treated with antibiotics and physiotherapy during the period of 12 weeks with complete recovery. Antineoplastic drugs that act via an antiangiogenic mechanism could trigger or facilitate osteonecrosis especially if patients are being treated with bisphosphonates (12). Serra et al. (13) reported a case of jaw bone necrosis one week after extraction of the mandibular molar in a patient with lung adenocarcinoma with metastasis. After the extraction, he was given bevacizumab which probably led to bone necrosis. The patient was treated with chlorhexidine rinses and antibiotics. Recently, herpes zoster infection has been reported as a cause of jaw osteonecrosis in two patients (14, 15). Jain et al. (14) reported a case of unusual oral complication of herpes zoster infection involving mandibular division of trigeminal nerve which resulted in osteonecrosis, spontaneous exfoliation of teeth and subsequent pathologic fracture of the mandible in the absence of other known predisposing factors. Pushpanshu et al. (15) also reported a case of the herpes zoster of the left maxillary division of the trigeminal nerve with bone necrosis and rapid tooth exfoliation. De Visscher et al. (16) reported a case of 47 year old patient who had ulcer with exposed bone on the lingual side of the teeth 47 and 48. The same authors stated that condition might appear spontaneously or following damage to the mucous membrane (16). They suggested that surgical smoothening of the exposed bone, surgical removal of necrotic bone or spontaneous sequestration could be treatment options that could help. Sonnier and Horning (17) described four cases of spontaneous exposure and sequestration of alveolar bone. While one case was associated with an allergic mucositis, the other three were idiopathic involving large lingual exostoses. Peters et al. (18) reported sponatneous sequestration on the lingual mandibular bone in the molar region in eleven patients. As also seen in our case, there were no any clinical and radiological features of osteomyelitis. Peters et al. (18) reported that the affected area in their patients showed a single small ulcer (2.2-4.6 mm) with central sequestrum which is also consistent with our finding. Contrary to the finding of Peters et al. for three of the patients, our patient did not have mandibular tori which might be a predisposing factor for osteonecrosis since it is a known fact that patients with osteonecrosis have unusually labile periostal response to irritation.
As seen in other similar case reports, the sequestra were associated with ulceration of the overlying mucosa which persisted from few days to as long as three months. In our case, it might be that local trauma from food intake or toothbrushing caused ischemia which led to the jaw necrosis. Some sites in the oral cavity are more prone to this type of trauma such as prominence of the mylohyoid ridge on the mandibule.
Lingual inclination of the mandibular molars protects the lingual gingiva from irritation during mastication, however in patients with missing molars or in the case of restorations with incorrect contours, food particles are not sufficiently rinsed thus increasing the risk of continuous trauma to the area (1). In our case, the patient had lower molars, albeit necrosis of the jaw was seen, moreover lesion healed after the tooth 48 was extracted. The other possible cause might be the lingual mandibular cortex which was located at the most distant point from the intraboney alveolar arteries that supply the mandible. Therefore, this zone might be more susceptible to sequestration (18).
We believe that the lesion on the lingual manidublar gingiva occured due to the tooth 48 with a deep periodontal pocket. It seems that osteonecrosis was due to the pulp necrosis on the tooth 48 and consequential pulpal-periodontal syndrome, hence the tooth was surgically removed.
Differential diagnosis might include: lymphomas, sarcoma, chronic osteomyelitis, cocaine abuse, neutropenic ulcerations, local trauma from dental treatment, self-inflicted lesions, topical use of adstrigent solutions (19).
The treatment of the avital bone might include several options. Generally, surgical treatment is usually not recommended due to the fact that this might foster further ischemia of the dense cortical bone with probable underlying compromised vascular supply. Whenever possible, avital bone is left to sequestrate by itself. A bone fragment can be left to spontaneously exfoliate or is carefully removed (1). The patients are usually treated with antibiotics, vasodilators and hyperbaric oxygen or surgical debridement is performed, however the results are very inconsistent.
This case highlights the fact that in some patients bone exposure might develop due to the periodontal-pulp syndrome i.e. pulp necrosis. An adequate treatment of osteonecrosis due to the periodontal-pulp syndrome consists of extraction of diseased tooth, removal of the necrotic bone and granulation tissue as well as bone remodelling.