Bis-phossy jaw, phossy jaw, and the 21st century: Bisphosphonate-associated complications of the jaws

A historical review of 'phossy jaw'

The aim of this article is to stimulate interest and discussion on the pathogenesis of 'phossy jaw'. Historical evidence from newspapers and articles of the time is presented, as other scientific evidence is largely absent. It has stimulated considerable interest in present-day media due to the struggles of nineteenth century reformers to improve working conditions against an apathetic government and weak enforcement of regulation. Those afflicted were often young women who suffered severe pain, loss of segments of jaw, and disfigurement.

Zoledronic acid increases the prevalence of medication-related osteonecrosis of the jaw in a dose dependent manner in rice rats (Oryzomys palustris) with localized periodontitis

OBJECTIVE

Investigate role of dose/duration of zoledronic acid (ZOL), a powerful anti-resorptive (pAR), on prevalence of medication-related osteonecrosis of the jaw (MRONJ) in rice rats (Oryzomys palustris), a species with natural susceptibility to food impaction-induced localized periodontitis (FILP). We hypothesize that ZOL induces MRONJ lesions in rice rats with FILP, and that the prevalence of MRONJ rises with increasing dose and duration of ZOL treatment.

METHODS

We performed a toxicology experiment with clinically-relevant doses of ZOL in female rats (N=230) fed standard (STD) rodent chow. At age 4weeks (baseline), 12 rats were necropsied. The rest were randomized into five groups that began to receive 0, 8, 20, 50 or 125μg/kg ZOL IV/q 4weeks. After 12, 18, 24 and 30weeks, subgroups (N=9-16) from each of the dose groups were necropsied. High-resolution macroscopic photos of all jaw quadrants were given a gross quadrant grade (GQG) (0-4 or MRONJ) that classified FILP lesion severity and determined presence of gross MRONJ. Quadrants with GQG≥1 were examined histopathologically. Logistic regression analysis (ZOL dose/duration) of MRONJ prevalence was completed.

RESULTS

We found: 1) 75% of 0μg/kg ZOL rats developed FILP lesions; 2) baseline rats and rats treated with 0μg/kg ZOL had no MRONJ; 3) 29 gross MRONJ cases were identified; 4) all gross MRONJ cases were confirmed histopathologically by the observation of exposed necrotic bone, and 53 new cases were discovered (total=82); 5) ZOL dose (P<0.001), but not duration (P=0.326), was a significant predictor of MRONJ prevalence; 6) 13% prevalence of gross MRONJ among all rats, with 22% prevalence among rats exposed to ZOL oncologic doses (20-125μg/kg); 7) 38% prevalence of histopathologic MRONJ among all rats, with 73% prevalence among rats exposed to ZOL oncologic doses.

CONCLUSIONS

This is the first experiment to show a dose response relationship between clinically relevant doses of ZOL and MRONJ prevalence.

[Focus: Drug-related osteonecrosis of the jaw]

Antiresorptives and antiangiogenics are treatments that have proven effective in oncology and the treatment of osteoporosis and they are increasingly prescribed. The care of these patients requires collaboration between the prescriber and the oral health professional to establish an optimized treatment plan. Therapeutic education of the patient is essential for him to understand the issues of good oral health and the adverse effects that can be caused by these treatments. The management is essentially based on the individual benefit/risk balance resulting from the general, local and inherent of the molecule risk factors. Management of drug-related osteonecrosis of the jaw should be as early as possible.

Antiresorptive drug-related osteonecrosis of the jaw

Nitrogen-containing and non-nitrogen-containing bisphosphonates have been implicated in the development of osteonecrosis of the jaw (ONJ), a condition termed bisphosphonate-related OHJ. Other antiresorptive drugs have been implicated in the development of OHJ, hence the new term antiresorptive drug-related ONJ. The underlying pathogenesis remains unclear, and no definite diagnosis or cure has been established for this debilitating condition. This article reviews some of the most common antiresorptive drugs with their associated risks of ONJ and the current understanding of the pathogenesis ONJ, and summarizes current clinical guidelines.

The phosphorous necrosis of the jaws and what can we learn from the past: a comparison of "phossy" and "bisphossy" jaw

INTRODUCTION

The osteopathology of the jaws associated with bone resorption inhibitors is a current topic that engages a variety of clinical specialists. This has increased after the approval of denosumab for treatment of osteoporosis and skeletal-related events in patients with solid malignancy. Early after the first publications, there is a possible connection between phosphorous necrosis of the jaws, a dreadful industrial disease mentioned, and bisphosphonate-induced pathology. The nineteenth century was the prime time for phosphorus necrosis of match factory workers.

RESULTS

This occurrence provides an interesting insight into the medical and surgical profession in the nineteenth century. There are striking parallels and repetition of current and old ideas in the approach to this "new disease." There are similar examples in case descriptions when compared with today's patients of bisphosphonate-related osteonecrosis of the jaws (BRONJ).

DISCUSSION

Phosphorus necrosis was first described in Austria. Soon after this, surgeons in German-speaking countries including well-known clinicians Wegner (1872) and von Schulthess-Rechberg (1879) pioneered the analysis, preventative measures, and treatment of this disease. The tendency at this time was to approach BRONJ as a "special kind of osteomyelitis" in pretreated and metabolically different bone. Not only the treatment strategy to wait until sequestrum formation with subsequent removal and preventative measures but also the idea of focusing on the periosteum as the triggering anatomical structure may have been adopted from specialists in the nineteenth century. Therefore, phosphorous necrosis of the jaw is an excellent example of "learning from the past."

Etiology and treatment of osteonecrosis of the mandible

AIM OF THE STUDY

Post-radiogenic osteonecrosis of the mandible is a serious complication in patients with combined treated head/neck tumors. Osteonecrosis of the mandible can also occur following administration of bisphosphonates. In the present article we would like to present our experiences over the last five years in treating both bisphosphonate-associated osteonecrosis and osteoradionecrosis.

MATERIAL AND METHODS

Of the patients treated in our hospital for bone necrosis of the mandible between January 2005 and June 2010, 16 were diagnosed with infected osteoradionecrosis and 10 with bisphosphonate-associated osteonecrosis. The patients with osteoradionecrosis were administered the classic osteomyelitis treatment. The same procedure was carried out on 5 of the 10 patients with bisphosphonate-associated osteonecrosis; the remaining 5 were treated conservatively due to advanced bone infection. The bone biopsies and specimens of both entities yielded by the surgical interventions were examined histologically after decalcification.

RESULTS

Of the 16 patients treated for infected osteoradionecrosis, 7 recovered after decortication and long-term antibiosis. In 7 cases consolidation did not occur until after osseous continuity resection. In 2 cases the progress of the intraosseous infection could not be stopped with treatment. A typical first symptom of bisphosphonate-associated osteonecrosis was an alveolus that would not heal after a tooth extraction. In 50% of patients with bisphosphonate-associated osteonecrosis recovery was successful with a combination of surgery and long-term antibiosis. In the other patients with advanced bisphosphonate-associated osteonecrosis no definitive cure for the infection of the necrotic bone was possible.

CONCLUSION

In terms of treatment, osteoradionecrosis proves complex, yet easier to treat than bisphosphonate-associated osteonecrosis. The removal of the infected bone tissue is often necessary, but it does not always lead to recovery. Therefore it can be concluded that prevention of intraosseous infection by consistent pretherapeutic dental hygiene is especially important.

Oncologic doses of zoledronic acid induce osteonecrosis of the jaw-like lesions in rice rats (Oryzomys palustris) with periodontitis

Though osteonecrosis of the jaw (ONJ) is temporally-associated with the use of nitrogen-containing bisphosphonates (N-BPs), a cause-and-effect relationship has not yet been established. We hypothesize that ONJ is a two-stage process in which: (1) risk factors initiate pathologic processes in the oral cavity that lead to a supranormal rate of hard tissue necrosis; and (2) powerful antiresorptives reduce the rate of removal of necrotic bone sufficiently to allow its net accumulation in the jaw. To test this hypothesis, we used the rice rat model of periodontitis. At age 28 days, rats (n = 15/group) were placed on a high-sucrose and casein diet to exacerbate the development of periodontitis. Animals were injected subcutaneously (SC) biweekly with vehicle or alendronate (ALN, 15 µg/kg), or IV once monthly with vehicle, a low dose (LD) of zoledronic acid (ZOL), or a high dose (HD) of ZOL and sacrificed after 6, 12, 18, and 24 weeks. Mandibles and maxillae were analyzed to determine the effects on the: (1) progression of periodontitis; (2) integrity of alveolar bone; (3) status of bone resorption and formation; (4) vascularity; and (5) osteocyte viability. We found that only HD-ZOL induced ONJ-like lesions in mandibles of rice rats after 18 and 24 weeks of treatment. These lesions were characterized by areas of exposed necrotic alveolar bone, osteolysis, a honeycomb-like appearance of the alveolar bone, presence of bacterial colonies, and periodontal tissue destruction. In addition, inhibition of bone formation, a paradoxical abolition of the antiresorptive effect of only HD-ZOL, increased osteocyte necrosis/apoptosis, and decreased blood vessel number were found after 18 and/or 24 weeks. Our study suggests that only HD-ZOL exacerbates the inflammatory response and periodontal tissue damage in rice rats, inducing bone lesions that resemble ONJ.

Effects of alendronate on bone healing after tooth extraction in rats

OBJECTIVES

Tooth extraction has been identified as an important risk factor for bisphosphonate-induced osteonecrosis of the jaw. Therefore, the main goal of this study was to determine the effects of alendronate on healing of the extraction socket and on interdental alveolar bone after tooth extraction in rats.

MATERIALS AND METHODS

Animals were injected subcutaneously with vehicle or alendronate for 3-4 weeks before the first mandibular molar was extracted and these treatments were continued during post-extraction periods of 10, 21, 35 and 70 days. Mandibles were processed to evaluate healing of the extraction socket and adjacent alveolar bone by assessing bone formation, bone resorption and vascularity by histomorphometric techniques.

RESULTS

Alendronate decreased new woven bone formation, blood vessel area, perimeter and number in the extraction socket at 10 days postextraction, but not at later time points. Furthermore, alendronate-treated rats had increased interdental alveolar bone volume and height only at 10 days postextraction. In addition, a 2.5-fold increase in the percentage of empty osteocyte lacunae was found in alveolar bone of alendronate-treated rats only at 10 days postextraction.

CONCLUSIONS

Alendronate transiently decreases bone formation and vascularity in the extraction socket and delays the removal of interdental alveolar bone after tooth extraction in rats.

Zoledronic acid delays wound healing of the tooth extraction socket, inhibits oral epithelial cell migration, and promotes proliferation and adhesion to hydroxyapatite of oral bacteria, without causing osteonecrosis of the jaw, in mice

Nitrogen-containing bisphosphonates such as zoledronic acid (ZOL) and pamidronate have been widely and successfully used for the treatment of cancer patients with bone metastases and/or hypercalcemia. Accumulating recent reports have shown that cancer patients who have received these bisphosphonates occasionally manifest bisphosphonate-related osteonecrosis of the jaw (BRONJ) following dental treatments, including tooth extraction. However, little is known about the pathogenesis of BRONJ to date. Here, to understand the underlying pathogenesis of BRONJ, we examined the effects of ZOL on wound healing of the tooth extraction socket using a mouse tooth extraction model. Histomorphometrical analysis revealed that the amount of new bone and the numbers of blood vessels in the socket were significantly decreased in ZOL-treated mice compared to control mice. Consistent with these results, ZOL significantly inhibited angiogenesis induced by vascular endothelial growth factor in vivo and the proliferation of endothelial cells in culture in a dose-dependent manner. In contrast, etidronate, a non-nitrogen-containing bisphosphonate, showed no effects on osteogenesis and angiogenesis in the socket. ZOL also suppressed the migration of oral epithelial cells, which is a crucial step for tooth socket closure. In addition, ZOL promoted the adherence of Streptococcus mutans to hydroxyapatite and the proliferation of oral bacteria obtained from healthy individuals, suggesting that ZOL may increase the bacterial infection. In conclusion, our data suggest that ZOL delays wound healing of the tooth extraction socket by inhibiting osteogenesis and angiogenesis. Our data also suggest that ZOL alters oral bacterial behaviors. These actions of ZOL may be relevant to the pathogenesis of BRONJ.

Pathophysiology, risk factors and management of bisphosphonate-associated osteonecrosis of the jaw: Is there a diverse relationship of amino- and non-aminobisphosphonates?

Reports of osteonecrosis of the jaw (ONJ) in patients receiving long-term bisphosphonate therapy have appeared in the literature since 2003. This condition involves avascular necrotic bone in the area of maxilla or mandibula and there may be a secondary infection. Most cases of ONJ have been reported in cancer patients receiving the intravenous aminobisphosphonates zoledronic acid and pamidronate monthly or q 3 week; of note these are also the two most commonly used agents of this class. Risk factors for ONJ include a history of trauma, dental surgery or dental infection and intravenous bisphosphonate administration; in addition, the extent and duration of exposure to bisphosphonates also seem to correlate with the risk. Although a direct causal relationship with bisphosphonates cannot be assumed, these agents may possibly contribute to the development of ONJ by suppression of bone remodeling in the jaw which leads to increased rates of bone mineralisation and accumulation of microfractures. Clodronate, a non-aminobisphosphonate, appears to have a different mechanism of suppressing bone remodeling compared with aminobisphosphonates, and this may explain why few cases of ONJ have been reported with clodronate despite extensive use over the past 20 years; however, the potential of clodronate to reduce the risk of ONJ while providing equivalent clinical benefit to the aminobisphosphonates needs to be substantiated in controlled clinical trials. Use of bisphosphonate therapy should be carefully planned in patients with metastatic bone disease who have risk factors for ONJ, and appropriate preventive measures taken to avoid the development of this condition.

Bisphosphonates et ostéo(chimio)nécrose maxillo-mandibulaire

INTRODUCTION

Maxillo-mandibular osteonecrosis is exceptional outside a context of cervico-facial radiotherapy. Bisphosphonates are non-metabolized pyrophosphate analogues which inhibit osteoclastic activity. Bisphosphonates are prescribed for the treatment of malignant hypercalcemia, osteolysis associated with metastatic bone disease, Paget's disease and osteoporosis. Maxillomandibular osteonecrosis with bisphosphonates can be observed in 1/10000 patients, but is probably underestimated due to lack of dental examination.

MATERIAL AND METHODS

We describe six cases of mandibular necrosis associated with bisphosphonates: five of them as part of their treatment regimen for a neoplastic condition and one for osteoporosis.

RESULTS

Two patients developed spontaneous bone necrosis. In two others, tooth extraction preceded the onset of osteonecrosis. In the last two patients, we noted a preexisting dental infection. All the histopathological examinations showed necrotic bone colonized by Actinomyces.

DISCUSSION

Bisphosphonate-induced osteonecrosis is only found in the maxillomandibular area because the jaws are the only bone in the skeleton exposed to the external environment. The mandible is rendered particularly prone to necrosis even after minor trauma because of its terminal vascularization. Careful oral examination is recommended before prescribing bisphosphonate therapy.

Osteonekrose der Kiefer unter Bisphosphonat-Langzeittherapie

For several decades bisphosphonates have been used to reduce skeletal related events in patients with both osteoporosis or bone metastases. Under long term application, besides the known therapy side effects, a new clinical picture has been described within the last few years. This is osteonecrosis of the jaws, which is characterized by its difficulty in treatment. Besides exposed jaw bone, the start of the disease usually lacks any symptoms. The typical clinical symptoms then are foetor ex ore, swelling, exsudation, loosening of teeth, pain or paresthesia. Later oro-antral/nasal or oro-cutaneous fistula can develop. The X-ray shows persisting tooth sockets after extractions and later cloudy radio-lucency, sequestra or fractures. The patient exposed to bisphosphonate can be grouped according to the risk for osteonecrosis: high risk patients with intravenous bisphosphonate therapy and additional chemo-, radiation or corticoid therapy--predominantly patients with a malignant underlying disease and bone metastases low risk patients with an oral bisphosphonate therapy without additional chemo-, radiation or corticoid therapy--preferably patients with non-corticoid-induced osteoporosis. Before starting a bisphosphonate therapy possible causes of infection should be treated and risk of injuries to the mucosa should be reduced according to the individual risk profile. This is supplemented by information of the patient about the risk of necrosis and the possibilities for prevention. Regular dental recall under bisphophonate therapy is emphasised for early recognition of possible problems. Prophylaxis is recommended for the prevention of periodontal infection combined with a follow up of removable denture for possible ulcera. Generally, conservative treatment measures are preferred to surgical ones. Inevitable operations are carried out non-traumatically using broad spectrum antibiotic prophylaxis until the day of suture removal (not before day 10). Long term follow up examinations are recommended.Patients with dental implants inserted before a bisphophonate therapy should be subject to intensive recall examinations. For patients undergoing or following a bisphosphonate therapy the indication for dental implants should be as strict as for patients following head and neck radiation therapy. In the present for patients with osteonecrosis, even after healing, dental implants are regarded as contra-indication. Therapy of the necrosis often requires general anaesthesia, hospitalisation, naso-gastral feeding tube and intravenous, systemic antiinfective treatment. The necrosis is removed completely and a tension free wound closure with vascularised tissue is intended. A literature review shows the metabolic effect of biphosphonates, the known pathogenesis of the bisphosphonate-induced jaw necrosis. It is essential to develop interdisciplinary communication, aiming at a joint care for this group of concerned patients and involving not only those medical disciplines, which order and use bisphosphonates, but especially dentists and maxillofacial surgeons.

Bisphosphonates and osteonecrosis of the jaw: cause and effect or a post hoc fallacy?

BACKGROUND

An increasing amount of reports are being published suggesting a relationship between the use of bisphosphonates (BPs) and the development of osteonecrosis of the jaw (ONJ). We reviewed the currently available evidence and explore the potential mechanisms of action based on the known effects of the concerned BP.

DESIGN

The MEDLine, Current Contents and Science Citation Index Expanded databases were queried and the results augmented by analyzing cited references and recent congress proceedings.

RESULTS

22 papers were included detailing 225 patients, all based on retrospective chart review without control groups. The prevalence of ONJ was estimated at 1.5%. The involved BPs were pamidronate, zoledronic acid, alendronate and risedronate, all potent nitrogen-containing agents. The most common symptom was pain (81.7%), although 12.2% of cases were asymptomatic. In 69.3% of patients ONJ was preceded by a dental extraction. At the time of diagnosis, 74.5% of patients were receiving chemotherapy and in 38.2% of cases corticosteroids were administered. Although various conservative and surgical treatment modalities were reported, residual sites of ONJ persisted in 72.5% of cases.

CONCLUSION

Although not enough evidence is available to prove a causal link, it seems that under specific circumstances local defenses can become overwhelmed resulting in ONJ.

Nekrosen der Kieferknochen unter Bisphosphonattherapie

Bisphosphonates are widely used in the treatment of cancer patients with hypercalcemia and bone metastases or in osteoporosis therapy. Current reports have focused on therapy-resistant osteonecrosis of the jaws as a possible side effect of bisphosphonates. Official German drug committees have recently warned about the possibility of these side effects. So far we have experience with 12 patients showing therapy-resistant osteonecrosis of the mandible under bisphosphonate medication, three of whom received oral bisphosphonates for osteoporosis treatment. Presentation of these three cases provides more information on this clinically important side effect of oral bisphosphonate medication, also in osteoporosis therapy.

Bisphosphonate Induced Osteochemonecrosis of the Jaws: An Ounce of Prevention May be Worth a Pound of Cure

Patient exposure to bisphosphonate drugs for the management of hypercalcemia of malignancy, osteolytic lesions of metastatic cancer and osteoporosis has led to increasing reports of osteochemonecrosis of the jaws (bis-phossy jaw). This serious and debilitating condition requires dental practitioners to be alert for signs and symptoms of this syndrome. Thus far, nitrogen containing bisphosphonates have been implicated as a causative agent. While only a small fraction of patients who have taken these agents will develop osteochemonecrosis, it seems that patients who have received intravenous bisphosphonates are at greater risk than those who have taken oral agents. Tooth extractions are the most frequently reported predisposing dental procedure. While appropriate management strategies for patients with osteochemonecrosis of the jaws are evolving, we are suggesting rational preventive protocols and therapies based upon current experience and knowledge. These recommendations may change over time as the profession gains more experience in managing these patients.

Does avascular necrosis of the jaws in cancer patients only occur following treatment with bisphosphonates?

INTRODUCTION

In the last decade, bisphosphonates were regularly used to treat osteoporosis and bone pain from diseases such as metastatic breast cancer, multiple myeloma and Paget's disease. Currently, the influence of bisphosphonates in development of avascular osteonecrosis of the jaws has been recognized by various authors. In many cancer patients chemotherapy and medications like steroids have also to be applied. Agreement exists that these drugs can initiate vascular endothelial cell damage and accelerate disturbances in the microcirculation of the jaws possibly resulting in thrombosis of nutrient end arteries. The role of bisphosphonates in cancer patients with previously treated jaws has yet to be elucidated.

PATIENTS

Four case reports of 'cancer' patients are described in whom osteonecrosis of the jaws was found. In two patients, the nitrogen-containing bisphosphonate zoledronic acid was prescribed for additional therapy of malignancy for a period of 45 up to 70 months. In another case, supportive treatment of breast cancer was offered using ibandronate. The fourth patient suffered avascular necrosis of the mandible without ever having taken bisphosphonates. In any case, revisional, as well as extended surgery has to be performed for osteonecrosis because neither conservative debridement nor antibiotic therapy have shown long term success, with or without bisphosphonates. No withdrawal of bisphosphonates was performed in view of the information on the direct correlation of total dosage and duration of drug intake to systemic incorporation and the long time for drug release.

CONCLUSION

According to our observations, withdrawal of bisphosphonates is not recommended when necrosis of the jaws has occurred.

Ostéonécrose des maxillaires chez des patients traités par bisphosphonates

INTRODUCTION

The latest generations of bisphosphonates constitute a major advance in the management of disorders including Paget's disease, osteoporosis, and osteolytic bone tumors. Recent reports describe numerous cases of osteonecrosis of the jaw in patients treated with bisphosphonates. Some of these reports mention predisposing factors, including surgical procedures, chemotherapy, and radiotherapy.

CASES

In the past 12 months, we have observed and treated 9 cases of maxillary osteonecrosis, which we present summarily.

DISCUSSION

Some of our cases (3 of 9), like many of those described in literature, do not present predisposing factors. The osteonecrosis may thus be due mainly to the effect of bisphosphonates that, by blocking bone remodeling, may cause excessive bone mineralization. If this hypothesis is confirmed, these cases of osteonecrosis may be due to excess doses. Better dose adjustment should thus help prevent this complication.

Kieferknochennekrosen als mögliche unerwünschte Wirkung von Bisphosphonaten

BACKGROUND

Bisphosphonates are widely used in the treatment of cancer patients with hypercalcemia and bone metastases or in osteoporosis therapy. Current reports have focused on therapy-resistant osteonecrosis of the jaws as a possible side effect of bisphosphonates. Official German drug committees have recently warned about the possibility of these side effects in the publication organs Deutsches Arzteblatt and Deutsche Apotheker Zeitung.

CASE REPORTS

So far we have had experience with seven patients showing therapy-resistant osteonecrosis of the mandible under bisphosphonate medication. The presentation of these cases is intended to call attention to this clinically important side effect of bisphosphonate medication.