Bisphosphonate-related osteonecrosis of the jaw: position paper from the Allied Task Force Committee of Japanese Society for Bone and Mineral Research, Japan Osteoporosis Society, Japanese Society of Periodontology, Japanese Society for Oral and Maxillofacial Radiology, and Japanese Society of Oral and Maxillofacial Surgeons

Fatal Bleeding in Conjunction with Mandibular Medication-related Osteonecrosis of the Jaw (MRONJ)

Here, we report a case of fatal bleeding in conjunction with mandibular medicationrelated osteonecrosis of the jaw (MRONJ). A 75-year-old Japanese man was referred to our department with osteonecrosis of the jaw due to bisphosphonate (BP) for multiple bone metastases from prostate cancer. Aggressive surgical intervention was ruled out due to a poor prognosis in terms of life expectancy. Death occurred due to hemorrhagic shock resulting from massive oral bleeding caused by necrosis of the mandible. Numerous reports have suggested that jaw necrosis is induced not only by BP, but also RANKL antibody, steroids, and molecularly-targeted agents. This suggests that the number of cases of MRONJ is likely to increase among elderly patients in whom general health is already poor. The American Association of Oral and Maxillofacial Surgery recommends aggressive treatment only in cases of stage 3 disease. Therefore, such a therapeutic strategy may only be available for cases of jaw necrosis in which the general health status of the patient is otherwise good. To prevent a life-threatening outcome in cases of MRONJ, physicians, who are responsible for determining the drug strategy, should cooperate with oral surgeons in determining the best therapeutic strategy.

Medication-related osteonecrosis of the jaw after tooth extraction in cancer patients: a multicenter retrospective study

Root amputation, immunosuppressive therapy, mandibular tooth extraction, pre-existing inflammation, and longer duration of treatment with bone-modifying agents were significantly associated with an increased risk of medication-related osteonecrosis of the jaw. Hopeless teeth should be extracted without drug holiday before the development of inflammation in cancer patients receiving high-dose bone-modifying agents.

INTRODUCTION

No studies have comprehensively analyzed the influence of pre-existing inflammation, surgical procedure-related factors such as primary wound closure, demographic factors, and drug holiday on the incidence of medication-related osteonecrosis of the jaw (MRONJ). The purpose of this study was to retrospectively investigate the relationships between these various factors and the development of MRONJ after tooth extraction in cancer patients receiving high-dose bone-modifying agents (BMAs) such as bisphosphonates or denosumab.

METHODS

Risk factors for MRONJ after tooth extraction were evaluated with univariate and multivariate analyses. The following parameters were investigated in all patients: demographics, type and duration of BMA use, whether BMA use was discontinued before tooth extraction (drug holiday), the duration of such discontinuation, the presence of pre-existing inflammation, and whether additional surgical procedures (e.g., incision, removal of bone edges, root amputation) were performed.

RESULTS

We found that root amputation (OR = 22.62), immunosuppressive therapy (OR = 16.61), extraction of mandibular teeth (OR = 12.14), extraction of teeth with pre-existing inflammation, and longer duration (≥ 8 months) of high-dose BMA (OR = 7.85) were all significantly associated with MRONJ.

CONCLUSIONS

Tooth extraction should not necessarily be postponed in cancer patients receiving high-dose BMA. The effectiveness of a short-term drug holiday was not confirmed, as drug holidays had no significant impact on MRONJ incidence. Tooth extraction may be acceptable during high-dose BMA therapy until 8 months after initiation.

Treatment outcomes and prognostic factors of medication-related osteonecrosis of the jaw: a case- and literature-based review

OBJECTIVES

The purpose of this study was to investigate the treatment outcomes and prognostic factors of medication-related osteonecrosis of the jaw (MRONJ) in Japanese patients.

PATIENTS AND METHODS

Among 409 cases, treatment outcomes and prognostic factors were investigated in 275 patients. In statistical analyses, the 1-year cumulative curative rate was calculated with the Kaplan-Meier method, and significance was examined with the Wilcoxon test. Cox's proportional hazards regression analysis was used for the multivariate analysis.

RESULTS

Resolution of the disease was achieved in 137 out of 275 MRONJ patients (49.8%). One-year cumulative curative rates were 39.8% in stage 1 patients, 26.3% in stage 2, and 19.0% in stage 3. The 1-year cumulative curative rates of treatment interventions were 17.2% for conservative treatment, 34.5% for sequestrectomy, and 40.7% for extended surgery including bone resection and segmental resection. As the prognostic factors of treatment outcomes, the type of medication, stage of MRONJ, and type of surgical intervention were identified as independent factors in a multivariate analysis.

CONCLUSION

These results suggest that surgical interventions may lead to a good prognosis in MRONJ patients.

CLINICAL RELEVANCE

This study indicated that surgical intervention for MRONJ might lead to improvement of prognosis and quality of life in MRONJ patients.

Long-term oral bisphosphonates delay healing after tooth extraction: a single institutional prospective study

Tooth extraction in patients receiving bisphosphonates is thought to be a risk factor for osteonecrosis of the jaw (ONJ); however, ONJ did not develop, even when tooth extraction was performed with continued oral bisphosphonate therapy. A drug holiday from bisphosphonates before tooth extraction may not be necessary.

INTRODUCTION

It is controversial whether bisphosphonate withdrawal is necessary prior to invasive procedures such as tooth extraction in order to prevent bisphosphonate-related osteonecrosis of the jaw (BRONJ). This study aimed to evaluate the clinical safety of continuing oral bisphosphonate therapy in patients undergoing tooth extraction.

METHODS

We prospectively enrolled 132 patients (20 men, 112 women) who were receiving oral bisphosphonates for the prevention or treatment of osteoporosis and required tooth extraction. All patients were managed using an identical protocol, which included preoperative antibiotic prophylaxis and did not necessarily require complete wound closure. The patients were classified into groups according to the duration of bisphosphonate administration: < 2 years (n = 51), 2-5 years (n = 41), 5-10 years (n = 28), and > 10 years (n = 12). The groups were compared regarding the time taken for the extraction socket to heal, and the occurrence of BRONJ. Follow-up duration was at least 3 months.

RESULTS

A total of 274 teeth were removed. Long-term oral bisphosphonate therapy for > 5 years significantly delayed the healing of the extraction socket in comparison with administration for < 5 years; however, BRONJ did not develop in any group. There was no prolongation of wound healing due to systemic risk factors such as glucocorticoid administration and diabetes mellitus. There were no adverse skeletal events such as bone fracture.

CONCLUSIONS

Patients who underwent tooth extraction with continued oral bisphosphonate therapy showed delayed healing of the extraction socket as the cumulative administration period prolonged, but BRONJ did not develop.

Prognostic factors for outcome of surgical treatment in medication-related osteonecrosis of the jaw

OBJECTIVES

The number of patients with medication-related osteonecrosis of the jaw (MRONJ) is increasing, but treatment remains controversial. Published papers and systematic reviews have suggested that surgical treatment is effective in patients with MRONJ. The purpose of this study was to determine whether preoperative University of Connecticut Osteonecrosis Numerical Scale (UCONNS), other serologic biomarkers, and size of necrosis are prognostic factors for outcome of surgical treatment in MRONJ.

MATERIALS AND METHODS

From January 2008 to December 2016, 65 patients diagnosed with MRONJ at the Department of Oral and Maxillofacial Surgery in College of Dentistry, Dankook University who required hospitalization and surgical treatment were investigated. Patient information, systemic factors, and UCONNS were investigated. In addition, several serologic values were examined through blood tests one week before surgery. The size of osteolysis was measured by panoramic view and cone-beam computed tomography in all patients. With this information, multivariate logistic regression analysis with backward elimination was used to examine factors affecting postoperative outcome.

RESULTS

In multivariate logistic analysis, higher UCONNS, higher C-reactive protein (CRP), larger size of osteolysis, and lower serum alkaline phosphate were associated with higher incidence of incomplete recovery after operation. This shows that UCONNS, CRP, serum alkaline phosphate, and size of osteolysis were statistically significant as factors for predicting postoperative prognosis.

CONCLUSION

This study demonstrated that CRP, UCONNS, serum alkaline phosphate, and size of osteolysis were statistically significant factors in predicting the prognosis of surgical outcome of MRONJ. Among these factors, UCONNS can predict the prognosis of MRONJ surgery as a scale that includes various influencing factors, and UCONNS should be used first as a predictor. More aggressive surgical treatment and more definite surgical margins are needed when the prognosis is poor.

Factors affecting development of medication-related osteonecrosis of the jaw in cancer patients receiving high-dose bisphosphonate or denosumab therapy: Is tooth extraction a risk factor?

Methods for preventing medication-related osteonecrosis of the jaw (MRONJ) in cancer patients who have received high-dose bisphosphonate (BP) or denosumab (Dmab) have not yet been established. Tooth extraction after starting medication has been believed to be a major risk factor for MRONJ, and therefore this procedure tends to be avoided. This study investigated the risk factors for MRONJ, with a special reference to the correlation between tooth extraction and development of MRONJ. One hundred and thirty-five cancer patients who were administrated high-dose BP or Dmab were enrolled in the study. Demographic factors, general condition, treatment factors, and dental findings were examined retrospectively using medical records and panoramic X-ray findings. The cumulative occurrence rate of MRONJ was calculated using the Kaplan–Meier method, and the correlation between these variables and development of MRONJ was analyzed by univariate and multivariate Cox regression analysis. MRONJ developed in 18 of 135 patients. The 1-, 2-, and 3-year cumulative occurrence rates were 8.6%, 21.5%, and 29.2%, respectively. The duration of medication before first visit to the dental unit and the presence of a tooth with clinical symptoms were significantly correlated with the development of MRONJ. The rate of MRONJ occurrence in patients who had teeth with clinical symptoms, but who did not undergo tooth extraction, became higher 2 years later than that in patients who underwent extraction of teeth with symptoms, although not significant. Early dental examination and effective preventative care to avoid infection/inflammation are important for preventing MRONJ.

Zoledronic acid exacerbates inflammation through M1 macrophage polarization

Background

Zoledronic acid (Zol), one of the bisphosphonates, is frequently utilized for the treatment of osteoporosis and bone metastasis. However, the onset of medication-related osteonecrosis of the jaw (MRONJ) following dental treatments has become a serious issue. We reported previously that osteonecrosis can be induced by Zol and lipopolysaccharide (LPS) in vivo, suggesting the involvement of Zol in inflammation. Macrophages are divided into M1/M2 macrophages. M1 macrophages are involved in the induction and exacerbation of inflammation and express proinflammatory mediators including interleukin (IL)-1. On the other hand, M2 macrophages are associated with anti-inflammatory reactions through the expression of anti-inflammatory cytokines, such as IL-10. In the present study, we clarified the effects of Zol on M1/M2 macrophage polarization in vitro.

Methods

Human monocytic THP-1 cells were polarized to macrophage-like cells by phorbol 12-myristate 13-acetate (PMA), and, after culturing for an additional 24 h with or without Zol, then polarized to M1 macrophages by LPS or to M2 macrophages by IL-4. Cell viability was examined by the WST-8 assay. Gene expression was confirmed by the real-time polymerase chain reaction. Protein expression was detected by western blotting and enzyme-linked immunosorbent assays.

Results

Zol treatment upregulated the expression of IL-1β mRNA and protein through NLRP3 inflammasome activation in LPS-treated THP-1 cells. Zol treatment did not affect the expression of IL-10, IL-1ra, or CD206 in IL-4-treated THP-1 cells.

Conclusions

Zol enhanced LPS-induced M1, but not M2, macrophage polarization through the NLRP3 inflammasome-dependent pathway, resulting in the production of inflammatory cytokines in THP-1 cells.

The influence of alendronate and tooth extraction on the incidence of osteonecrosis of the jaw among osteoporotic subjects

BACKGROUND

Although bisphosphonate-related osteonecrosis of the jaw (ONJ) develops mainly after tooth extractions (TEs), the strength of the association between them and how the existence of the disease among bisphosphonate (BP)-treated osteoporotic patients exposed to TE remain uncertain.

METHODS

A nationwide retrospective cohort study investigated the influence of alendronate and TE on the development of ONJ.

RESULTS

Incidence of ONJ following long-term alendronate therapy was 262/100,000 person-years, while no event developed in the control group on raloxifene. Overall prevalence of ONJ in osteoporotic subjects receiving alendronate was estimated at 0.34% which rose to 2.16% after TE. Multiple logistic regression analysis, adjusted for the potential confounders, showed TE (adjusted odds ratio, 9.60 [4.33-21.29]), drug duration exceeding 3 years (3.00 [1.33-6.76]), and concomitant rheumatoid arthritis (4.94 [1.64-14.90]) were independent predictors of ONJ.

CONCLUSIONS

This article strengthens the relationship between ONJ and BPs. Among osteoporotic patients exposed to alendronate, TE confers a 9.6-fold increased risk for ONJ and it should be performed with caution irrespective of drug duration.

National Survey on Bisphosphonate-Related Osteonecrosis of the Jaws in Japan

PURPOSE

From 2011 to 2013, a nationwide retrospective cohort study was conducted by the Japanese Society of Oral and Maxillofacial Surgeons and the Japanese Society of Dentistry for Medically Compromised Patients to assess the development of bisphosphonate (BP)-related osteonecrosis of the jaws (BRONJ) and to elucidate the outcomes and factors associated with remission.

MATERIALS AND METHODS

A written questionnaire, including clinical characteristics, management, and outcomes of patients with BRONJ, was sent to 501 institutions.

RESULTS

This large-scale study included 4,797 cases with a female preponderance. BRONJ occurred twice as often in the mandible as in the maxilla. Most patients had BRONJ stage 2 (61.4%), followed by stage 1 (20.7%) and stage 3 (16.8%); stage 0 was excluded. The most common primary disease was malignant neoplasm (46.5%), followed by osteoporosis (including prevention; 45.3%). The proportion of patients on oral BPs increased, with the incidence approaching that of patients receiving parenteral BP. Surgical therapy rates of patients with BRONJ stages 1, 2, and 3 were 14.0, 37.6, and 53.5%, respectively. Outcome assessment for 936 patients with BRONJ stage 2 who underwent surgical therapy indicated remission in 46.3% of cases, improvement in 30.6%, disease progression in 5.4%, and no change in 6.1%. Good prognosis (remission or improvement) was seen in 76.9% of cases and poor prognosis (disease progression or no change) was seen in 11.5%. Analysis showed that risk factors for onset of BRONJ (P = .031), surgical procedure (P < .024), condition of the wound (P = .017), and discontinuation of BP (P < .001) were factors affecting prognosis.

CONCLUSION

The number of patients with BRONJ has increased in Japan. Attention to oral BP and proper treatment is required to minimize the number of cases. Surgical therapy seems to be effective for BRONJ stage 2.

Evaluation of the Treatment Strategies for Medication-Related Osteonecrosis of the Jaws (MRONJ) and the Factors Affecting Treatment Outcome: A Multicenter Retrospective Study with Propensity Score Matching Analysis

Medication-related osteonecrosis of the jaw (MRONJ) is an adverse event that may inhibit the treatment of primary disease and remarkably influence the patient's quality of life. The treatment methods for MRONJ, nonsurgical and surgical, are controversial, with no agreement as to which method provides the best outcome and should therefore be recommended. This multicenter retrospective study aimed to investigate the treatment methods and outcome in a large number of patients with MRONJ in Japan, utilizing propensity score matching analysis. A total of 361 patients with MRONJ, at eight hospitals, were registered in this study retrospectively. Various demographic and treatment-related variables were examined and analyzed to determine their correlation with the treatment outcome. After propensity score matching for treatment methods (nonsurgical versus surgical treatment), 176 patients were analyzed by logistic regression. It was shown that those with low-dose administration of an antiresorptive agent and surgical treatment had better outcomes. Furthermore, in 159 patients who underwent surgical treatment, those who underwent extensive surgery experienced significantly better treatment outcomes than those who underwent conservative surgery. This is the first study to compare treatment methods for MRONJ using propensity score matching analysis. The results indicated that extensive surgical treatment should be performed as first-choice therapy for patients with MRONJ. © 2017 American Society for Bone and Mineral Research.

Selective Percutaneous Controlled Radiofrequency Thermocoagulation of the Gasserian Ganglion To Control Facial Pain Due to Medication-Related Osteonecrosis of the Jaw

BACKGROUND

Medication-related osteonecrosis of the jaw (MRONJ) is an important complication in patients treated with antiresorptive agents such as bisphosphonates and the receptor activator of nuclear factor κB ligand inhibitor (denosumab). Treatment of MRONJ is extremely difficult, which makes it a distressing long-term complication.

OBJECTIVES

We report a case of intractable facial pain due to MRONJ that was successfully controlled with selective percutaneous controlled radiofrequency thermocoagulation of the Gasserian ganglion.

SETTING

A 68-year-old woman with breast cancer was diagnosed as having MRONJ. She was very distressed because of jaw pain and infections secondary to MRONJ. Her quality of life (QOL) was severely decreased. Since alleviation of the MRONJ could not be expected within the patient's life expectancy, it was decided to investigate the usefulness of selective percutaneous controlled radiofrequency thermocoagulation of the Gasserian ganglion to control the pain.

RESULTS

After the procedure, the anesthesia was obtained in the distribution of the third branch of the trigeminal nerve, and the pain completely disappeared. Although hypoesthesia was provoked as a complication, it was tolerated by the patient and she was very satisfied. Up to the time of death, there was no recurrence of pain or worsening of the MRONJ.

DISCUSSION

This procedure is a common technique for treating trigeminal neuralgia. Its effect is immediate and long lasting, although it provokes hypoesthesia in treated division, and it is also suited for cancer patients in terminal stage. This case suggests that the procedure was useful for improving the patient's QOL.

A multicenter retrospective study of the risk factors associated with medication-related osteonecrosis of the jaw after tooth extraction in patients receiving oral bisphosphonate therapy: can primary wound closure and a drug holiday really prevent MRONJ?

Root amputation, extraction of a single tooth, bone loss or severe tooth mobility, and an unclosed wound were significantly associated with increased risk of developing medication-related osteonecrosis of the jaw (MRONJ). We recommend a minimally traumatic extraction technique, removal of any bone edges, and mucosal wound closure as standard procedures in patients receiving bisphosphonates.

INTRODUCTION

Osteonecrosis of the jaws can occur following tooth extraction in patients receiving bisphosphonate drugs. Various strategies for minimizing the risk of MRONJ have been advanced, but no studies have comprehensively analyzed the efficacy of factors such as primary wound closure, demographics, and drug holidays in reducing its incidence. The purpose of this study was to retrospectively investigate the relationships between these various risk factors after tooth extraction in patients receiving oral bisphosphonate therapy.

METHODS

Risk factors for MRONJ after tooth extraction were evaluated using univariate and multivariate analysis. All patients were investigated with regard to demographics; type and duration of oral bisphosphonate use; whether they underwent a discontinuation of oral bisphosphonates before tooth extraction (drug holiday), and the duration of such discontinuation; and whether any additional surgical procedures (e.g., incision, removal of bone edges, root amputation) were performed.

RESULTS

We found that root amputation (OR = 6.64), extraction of a single tooth (OR = 3.70), bone loss or severe tooth mobility (OR = 3.60), and an unclosed wound (OR = 2.51) were significantly associated with increased risk of developing MRONJ.

CONCLUSIONS

We recommend a minimally traumatic extraction technique, removal of any bone edges, and mucosal wound closure as standard procedures in patients receiving bisphosphonates. We find no evidence supporting the efficacy of a pre-extraction short-term drug holiday from oral bisphosphonates in reducing the risk of MRONJ.

A case of tooth fracture occurred upon medicating bisphosphonate for an elderly person: Preservation therapy and responses for Stage 0 of bisphosphonate-related osteonecrosis of jaw

This case report aimed to report the progress of preservation therapy and response of symptoms and signs for Stage 0 of bisphosphonate-related osteonecrosis of jaw (BRONJ). A 68-year-old female was recognized having a tooth at the left upper first molar fracture upon medicating bisphosphonate (BP) in 2007. At that time, the extraction of the tooth was an absolute contraindication. Therefore, we performed preservation therapy. We observed the symptoms and signs every month. After 5 months, swelling and redness in the entire first molar tooth were seen and fistula formed partly. Bone exposure was not seen. We administrated antibiotics immediately. As a result, symptoms disappeared. On April 10, 2009, the patient visited us as she felt a sense of incongruity in the lower left first and second molar teeth. Clinically, there were no symptoms of pain. However, we observed the radiolucent finding in about 5 mm diameter at apical position by X-ray photography; we considered a possibility of Stage 0 for BRONJ. We immediately administered medicine for 5 days and the symptoms disappeared. At present, no inflammation with signs and symptoms at the upper left first molar and lower left first, second molar parts is shown. We performed preservation therapy for tooth fracture case medicating of BP. Immediate responses for inflammation and symptoms of the Stage 0 of BRONJ have led to success. Hence, dentists should perform regular clinical observation, and enough education to the patient for BRONJ is necessary.

The effect of chronic dental inflammation on development of Stage 0 medication-related osteonecrosis of the jaw

OBJECTIVE

The pathogenesis of medication-related osteonecrosis of jaw (MRONJ) is poorly understood. The aim of this prospective study was to determine the effect of chronic dental inflammation on the development of Stage 0 MRONJ based on histopathological findings.

METHODS

The study involved patients with a history of bisphosphonate use and an indication for tooth extraction. Before surgery, C-terminal telopeptide test (CTX) values were collected from all patients. All tooth extractions were performed according to a determined protocol. To detect whether any medication-related osteonecrotic changes were present in the non-exposed bone, biopsy samples were taken from the alveolar bone.

RESULTS

A total of 50 patients were included in the study (39 women and 11 men). The patients were mean age of 57.4 ± 12.1 years. In total, 74 teeth were extracted (29 maxillary and 45 mandibular). Histologic examination of three patients (6%) revealed Stage 0 MRONJ. Postoperatively, the complete mucosal healing success rate was 96%. MRONJ risk was not significantly correlated with low CTX value (p = 0.285).

CONCLUSIONS

Chronic inflammation may contribute to Stage 0 MRONJ; however, its role may not be sufficient alone for its development. Application of a predetermined protocol for dentoalveolar processes will help to prevent MRONJ development.

Antiresorptive agent-related osteonecrosis of the jaw in osteoporosis patients from Asian countries

Bisphosphonate (BP)-associated osteonecrosis of the jaw (ONJ) was first reported in oncology patients in 2003 and subsequently in osteoporosis patients in 2004. Since oral surgical procedures, such as tooth extraction, are also considered one of the major risk factors for ONJ, there is confusion among physicians, dentists, and patients—particularly osteoporosis patients currently taking BPs—regarding the safety of remaining on therapy surrounding these procedures. Many papers about BP-related ONJ (BRONJ) have been published to date. In addition to BRONJ, recent studies have reported an association between ONJ and the antiresorptive therapy denosumab (Dmab; a RANKL-inhibitor). BRONJ and Dmab-related ONJ are together referred to as antiresorptive agent-related ONJ (ARONJ). The pathogenesis of ARONJ still remains unknown. It is forecasted that there will be an increased incidence of patients with osteoporotic fractures and an increased number of prescriptions for antiresorptive agents in Asia in the future. However, prescriptions for antiresorptives for osteoporosis may be restricted in the Asian population as the occurrence of ARONJ may be higher as compared with those in other countries. In this review, we focused on the following topics as it pertains to the Asian osteoporotic population: the oral condition specific for osteoporosis patients; definition, staging, prevalence and incidence of ARONJ; imaging modalities for ARONJ; specific risk factors for ARONJ; prevention strategies for ARONJ, and; cooperation between physicians and dentists in the prevention of ARONJ. Ideally, the Asian Federation of Osteoporosis Societies would cooperate with one another and find more population-specific evidence for the prevention of ARONJ.

Treatment of stage II medication-related osteonecrosis of the jaw with necrosectomy and autologous bone marrow mesenchymal stem cells

Treatment strategies for medication-related osteonecrosis of the jaw (MRONJ) remain controversial. Although the AAOMS suggests a conservative approach, a surgical management with necrosectomy is often required when conservative management has failed. Moreover, recent studies have shown promising results using an early stage surgical treatment. Over the past decade, cell-based bone regeneration utilizing bone marrow mesenchymal stem cells (MSCs) received increased attention. MSCs are known to promote wound healing and induce new bone formation in compromised tissue. Accordingly, the aim of this study was to assess the role of MSCs in the management of MRONJ. This study included 6 patients referred to our department with the diagnosis of MRONJ. Upon informed consent, the patients underwent surgical resection of necrotic bone followed by MSCs grafting. The MSCs were separated from bone marrow cells aspirated from the iliac crest using a bone marrow aspirate concentrate system. The MSCs were grafted into the defect with autologous thrombin and the defect was covered with a collagen membrane. In all cases, bony edges were rounded and the wound was closed using a three-layered technique. In the follow-up from 12 to 54 months, all patients including those who had impaired conditions, sepsis, or pathological fracture, showed satisfactory healing with no signs of wound infection. This pilot study indicated that surgical management in combination with MSCs transplantation seems to be a promising treatment modality in the therapy of MRONJ.

Antiresorptive agent-related osteonecrosis of the jaw: Position Paper 2017 of the Japanese Allied Committee on Osteonecrosis of the Jaw

Antiresorptive agent-related osteonecrosis of the jaw (ARONJ) is an intractable, though rare, complication in cancer patients with bone metastases and patients with osteoporosis who are treated with antiresorptive agents, including bisphosphonates and denosumab. Despite the more than 10 years that have passed since the first cases of bisphosphonate-related osteonecrosis of the jaw (BRONJ) were reported, our understanding of the epidemiology and pathophysiology of ARONJ remains limited, and data supported by evidence-based medicine are still sparse. However, the diagnosis and staging of ARONJ, identification of risk factors, and development of preventive and therapeutic approaches have advanced significantly over the past decade. The Position Paper 2017 is an updated version of the Position Paper 2010 of the Japanese Allied Committee on Osteonecrosis of the Jaw, which now comprises six Japanese academic societies. The Position Paper 2017 describes a new diagnostic definition for ARONJ, as proposed by the American Association of Oral and Maxillofacial Surgeons (AAOMS), summarizes our current understanding of the pathophysiology of ARONJ based on a literature search, and suggests methods for physicians and dentists/oral surgeons to manage the disease. In addition, the appropriateness of discontinuing antiresorptive medications (drug holiday) before, during, and after invasive dental treatments is discussed extensively. More importantly, the manuscript also proposes, for the first time, the importance of interactive communication and cooperation between physicians and dentists/oral surgeons for the successful treatment of ARONJ. The Position Paper 2017 is intended to serve as a guide for improving the management of ARONJ patients in Japan.

Treatment of medication-related osteonecrosis of the jaws (MRONJ) with ultrasonic piezoelectric bone surgery. A case series of 20 treated sites

PURPOSE

There is no consensus on how to successfully treat medication-related osteonecrosis of the jaws (MRONJ). We report here on the application of piezoelectric bone surgery to treat MRONJ in combination with antibiotherapy and on its possible benefit.

MATERIEL AND METHODS

A cohort of 18 consecutive patients has been treated for MRONJ; they involved 20 sites, 15 in the mandible, and five in the maxilla. Surgical removal of the necrotic areas and debridement was performed with a powerful piezoelectric surgery device (max 90 W) in combination with antibiotherapy.

RESULTS

All patients healed and obtained a complete soft tissue closure within 1 month. No recurrence of the symptoms was observed during the present follow-up (10-54 months).

CONCLUSION

We hypothesize that healing of all treated sites might have resulted from the synergic effect of bone ablation, biofilm alteration, and antibiotic administration. Biofilm alteration might have permitted a better access of antibiotics to the involved germs. These encouraging results warrant further studies on the use of ultrasonic surgery to treat MRONJ patients in order to confirm or refute the hypothesized effect.

Multipotent mesenchymal stromal cell sheet therapy for bisphosphonate-related osteonecrosis of the jaw in a rat model

Bisphosphonates (BPs) inhibit bone resorption and are frequently used to treat osteoporosis, bone metastasis, and other conditions that result in bone fragility. However, numerous studies have reported that BPs are closely related to the development of osteonecrosis of the jaw (BRONJ), which is an intractable disease. Recent studies have demonstrated that intravenous infusion of multipotent mesenchymal stromal cells (MSCs) is effective for the treatment of BRONJ-like disease models. However, the stability of injected MSCs is relatively low. In this study, the protein level of vascular endothelial growth factor in BP-treated MSCs was significantly lower than untreated-MSCs. The mRNA expression levels of receptor activator of nuclear factor κ-B ligand and osteoprotegerin were significantly decreased in BP-treated MSCs. We developed a tissue-engineered cell sheet of allogeneic enhanced green fluorescent protein (EGFP)-labeled MSCs and investigated the effect of MSC sheet transplantation in a BRONJ-like rat model. The MSC sheet group showed wound healing in most cases compared with the control group and MSC intravenous injection group (occurrence of bone exposure: 12.5% compared with 80% and 100%, respectively). Immunofluorescence staining revealed that EGFP-positive cells were localized around newly formed blood vessels in the transplanted sub-mucosa at 2weeks after transplantation. Blood vessels were significantly observed in the MSC sheet group compared to in the control group and MSC intravenous injection group (106±9.6 compared with 40±5.3 and 62±10.2 vessels/mm(2), respectively). These results suggest that allogeneic MSC sheet transplantation is a promising alternative approach for treating BRONJ.

STATEMENT OF SIGNIFICANCE

Bisphosphonates are frequently used to treat osteoporosis, bone metastasis of various cancers, and other diseases. However, bisphosphonate related-osteonecrosis of the jaw (BRONJ) is an intractable disease because it often recurs after surgery or is exacerbated following conservative treatment. Therefore, an alternative approach for treating BRONJ is needed. In this study, we developed a bone marrow-derived multipotent mesenchymal stromal cell (MSC) sheet to treat BRONJ and investigated the effect of MSC sheet transplantation in a rat model of BRONJ-like disease. The MSC sheet transplantation group showed wound healing in most cases, while only minimal healing was observed in the control group and MSC intravenous injection group. Our results suggest that the MSC sheet is a promising alternative approach for the treatment of BRONJ.

Differential modulation of zoledronate and etidronate in osseous healing of an extracted socket and tibia defect

OBJECTIVES

Osteonecrosis of the jaw has been increasing after dentoalveolar surgery in patients treated with an antiresorptive bisphosphonate (BP), especially strong zoledronate (ZA). The pathophysiology underlying why osteonecrosis occurs exclusively in the jaw bone remains unclear. This study investigated skeletal site-specific bone healing during the use of BPs to explore the preferential incidence of osteonecrosis of the jaw bone.

STUDY DESIGN

Extraction of mandibular molar and creation of a tibia defect were performed in rats 2 weeks after weekly intravenous injections with the potent ZA and the weaker BP etidronate. Bone healing was evaluated radiographically and histologically 1 and 4 weeks after defect creation.

RESULTS

Bone healing at the extracted socket showed that resorption precedes bone formation, while it was the opposite at the tibia defect. ZA use potentially suppressed bone remodeling, which led to impaired healing at the extracted socket but full regeneration of the tibia defect. However, etidronate showed less suppression of bone remodeling and resulted in increased bone formation at the extracted socket and full regeneration of the tibia defect.

CONCLUSIONS

These results suggest that skeletal site-dependent differences in the bone healing process underlie BP-related preferential occurrence of osteonecrosis of the jaw bone.

Osteonecrosis of the Jaw in the Absence of Antiresorptive or Antiangiogenic Exposure: A Series of 6 Cases

PURPOSE

Medication-related osteonecrosis of the jaws (MRONJ) is a well-described complication of antiresorptive and antiangiogenic medications. Although osteonecrosis can be associated with other inciting events and medications, such as trauma, infection, steroids, chemotherapy, and coagulation disorders, these are rarely reported in the literature.

MATERIALS AND METHODS

This is a six case series of MRONJ associated with medications other than antiresorptive or antiangiogenic drugs.

RESULTS

Patient demographics, inciting event, location, stage, imaging findings, and outcome are reported.

CONCLUSION

With the continued development and clinical use of new biologic medications for diseases such as cancer and rheumatoid arthritis, it is important to continue to evaluate their effects on the oral cavity. The degree of risk for osteonecrosis in patients taking these new classes of drugs is uncertain but warrants awareness and monitoring.

Lack of cooperation between physicians and dentists during osteoporosis treatment may increase fractures and osteonecrosis of the jaw

OBJECTIVE

Our previous questionnaire-based survey suggested that discontinuation of antiresorptive agents before tooth extraction may increase adverse events and disturb osteoporosis treatment without completely preventing osteonecrosis of the jaw (O.N.J.). We also found little cooperation between physicians and dentists in Japan. However, limitations of our previous study included a survey of doctors belonging to small clinics and a small sample size. Our current study aimed to confirm the results of our previous survey in doctors mainly belonging to academia.

METHODS

A structured questionnaire including 14 key clinical queries was sent to 1812 physicians of the Japan Osteoporosis Society, and 629 responses were received.

RESULTS

Dentists requested discontinuation of many medications that were not associated with the incidence of O.N.J. A total of 523 respondents had received discontinuation requests from dentists. Of these, 97 respondents experienced 119 adverse events including 25 fractures and seven incidences of O.N.J. The ratios of valid responses for fractures were 3.6% and 5.3% in patients with a discontinuation of <3 and ≥3 months, respectively. Those for O.N.J. were 0.7% and 1.6%, respectively. Respondents who refused discontinuation requests reported no cases of O.N.J. Approximately 17% of respondents had patients who discontinued osteoporosis treatment following a requested drug discontinuation after tooth extraction. Approximately 62% of respondents did not request oral health care by a dentist before antiresorptive therapy, and 72% reported no cooperation between physicians and dentists in their region.

CONCLUSIONS

This study reconfirms the results of our previous survey. Discontinuation of antiresorptive treatment may increase both fractures and O.N.J. Immediate development of a strategy for sharing information about O.N.J. among physicians, dentists, and patients is required to reduce the incidence of both O.N.J. and skeletal events in osteoporosis treatment. Study limitations were selection bias due to low response rate and possible inaccurate responses to the questionnaire.

Computed tomographic assessment of early changes of the mandible in bisphosphonate-treated patients

OBJECTIVES

To compare the computed tomography (CT) features of mandibular cancellous and cortical bones between patients with bisphosphonate (BP) administration and those without and to assess the early changes of the mandible in BP-treated patients.

STUDY DESIGN

Twenty-four BP-treated patients suffering from medication-related osteonecrosis of the jaw (MRONJ) were enrolled in this study. For comparison, 20 patients suffering from osteomyelitis and 20 patients without pathology in the jaw were also enrolled, all of whom did not receive BP treatment. The CT values of the cancellous and cortical bone and the cortical bone widths were measured.

RESULTS

In the MRONJ and osteomyelitis groups, there were significant differences in the CT values of cancellous and cortical bones between the affected and unaffected areas. In patients with stage 0 MRONJ, a significant difference was noted in the cancellous bone CT values between these areas. The cancellous bone CT values at the affected and unaffected areas in the BP-treated group were significantly higher than in the control groups. In patients with stage 0 MRONJ, the cancellous bone CT values at the affected area were also significantly higher than in the healthy patients. The cortical bone widths in the unaffected areas in the BP-treated patients were significantly larger than in healthy patients.

CONCLUSIONS

The cancellous bone CT values were higher in the BP-treated group, including in patients with stage 0 MRONJ, and CT may provide useful quantitative information.

Concept, diagnosis and classification of bisphosphonate-associated osteonecrosis of the jaws. A review of the literature

Background

Bisphosphonates (BPs) and other antiresorptive agents such as denosumab are widely prescribed for the treatment of osteoporosis and are also used in patients with multiple myeloma and metastatic breast or prostate cancer for avoiding bone reabsorption and fractures that result in increased morbidity-mortality among such individuals.

Material and Methods

We made a bibliographic search to analyze the concept, diagnosis and the different classifications for bisphosphonate-associated osteonecrosis of the jaws.

Results

Osteonecrosis of the jaws (ONJ) is an important complication of exposure to BPs or other antiresorptive agents, and although its prevalence is low, it can pose management problems. The definition, diagnosis and classification of osteonecrosis have evolved since Marx reported the first cases in 2003.

Conclusions

The present study offers a literature review and update on the existing diagnostic methods and classification of the disorder, with a view to facilitating earlier and more effective treatment.

Key words:Osteonecrosis, jaws, bisphosphonates.

Assessing the utility of serum C-telopeptide cross-link of type 1 collagen as a predictor of bisphosphonate-related osteonecrosis of the jaw: A systematic review and meta-analysis

BACKGROUND

The authors of this systematic review and meta-analysis assessed the utility of serum C-telopeptide cross-link of type 1 collagen (sCTX), a biomarker of bone resorption, as a predictor of the development of bisphosphonate-related osteonecrosis of the jaw (BRONJ).

TYPES OF STUDIES REVIEWED

The authors searched for studies involving adult participants, written in English, and published through January 20, 2016, using the following electronic databases: the Cochrane Library, MEDLINE via PubMed, and Web of Science. They also searched Google Scholar and the reference lists of all eligible trials and reviews. They identified 16 articles that met their inclusion criteria (9 controlled studies and 7 case series). They applied the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines for systematic reviews and meta-analyses. They independently extracted data in duplicate, including the characteristics of study participants, risk factors, control groups, and outcomes. They assessed risk of bias, and they resolved any disagreements between review authors through discussion.

RESULTS

A meta-analysis with 9 controlled studies revealed no significant difference in mean sCTX values between patients with BRONJ and control participants (difference in means, -31.417; 95% confidence interval [CI], -91.560 to 28.726; P = .306). A second meta-analysis with 4 studies showed no significant difference in risk of having an sCTX value below 150 picograms per milliliter for patients with BRONJ compared with control participants (risk ratio, 1.892; 95% CI, 0.636-5.626; P = .251).

CONCLUSIONS AND PRACTICAL IMPLICATIONS

A systematic review of the literature with meta-analysis does not support the use of sCTX levels as a predictor of the development of BRONJ. Further prospective large sample studies are needed to understand the role of sCTX as a predictor for BRONJ.

Zoledronic acid increases the circulating soluble RANKL level in mice, with a further increase in lymphocyte-derived soluble RANKL in zoledronic acid- and glucocorticoid-treated mice stimulated with bacterial lipopolysaccharide

The nitrogen-containing bisphosphonate (BP) zoledronic acid (ZA) is a potent antiresorptive drug used in conjunction with standard cancer therapy to treat osteolysis or hypercalcemia due to malignancy. However, it is unclear how ZA influences the circulating levels of bone remodeling factors. The aim of this study was to evaluate the effects of ZA on the serum levels of soluble receptor activator of NF-kB ligand (sRANKL) and osteoprotegerin (OPG). The following four groups of C57BL/6 mice were used (five mice per group): (1) the placebo+phosphate-buffered saline (PBS) group, in which placebo-treated mice were injected once weekly with PBS for 4weeks; (2) the placebo+ZA group, in which placebo-treated mice were injected once weekly with ZA for 4weeks; (3) the prednisolone (PSL)+PBS group, in which PSL-treated mice were injected once weekly with PBS for 4weeks; and (4) the PSL+ZA group, in which PSL-treated mice were injected once weekly with ZA for 4weeks. At the 3-week time point, all mice were subjected to oral inflammatory stimulation with bacterial lipopolysaccharide (LPS). The sera of these mice were obtained every week and the levels of sRANKL and OPG were measured using enzyme-linked immunosorbent assay. At the time of sacrifice, femurs were prepared for micro-computed tomography (micro-CT), histological, and histomorphometric analyses. Our data indicated that ZA administration remarkably reduced bone turnover and significantly increased the basal level of sRANKL. Interestingly, the PSL+ZA group showed a dramatically elevated sRANKL level after LPS stimulation. In contrast, the PSL+ZA group in nonobese diabetic mice with severe combined immunodeficiency disease (NOD-SCID mice), which are characterized by the absence of functional T- and B-lymphocytes, showed no increase in the sRANKL level. Our data suggest that, particularly with combination treatment of ZA and glucocorticoids, surviving lymphocytes might be the source of inflammation-induced sRANKL. Thus, circulating sRANKL levels might be modulated by ZA.

Prevention of medication-related osteonecrosis of the jaws secondary to tooth extractions. A systematic review

Background

A study was made to identify the most effective protocol for reducing the risk of osteonecrosis of the jaws (ONJ) following tooth extraction in patients subjected to treatment with antiresorptive or antiangiogenic drugs.

Material and Methods

A MEDLINE and SCOPUS search (January 2003 - March 2015) was made with the purpose of conducting a systematic literature review based on the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines. All articles contributing information on tooth extractions in patients treated with oral or intravenous antiresorptive or antiangiogenic drugs were included.

Results

Only 13 of the 380 selected articles were finally included in the review: 11 and 5 of them offered data on patients treated with intravenous and oral bisphosphonates, respectively. No randomized controlled trials were found – all publications corresponding to case series or cohort studies. The prevalence of ONJ in the patients treated with intravenous and oral bisphosphonates was 6,9% (range 0-34.7%) and 0.47% (range 0-2.5%), respectively. The main preventive measures comprised local and systemic infection control.

Conclusions

No conclusive scientific evidence is available to date on the efficacy of ONJ prevention protocols in patients treated with antiresorptive or antiangiogenic drugs subjected to tooth extraction.

Key words:Bisphosphonates, angiogenesis inhibitors, antiresorptive drugs, extraction, osteonecrosis.

Role of microcracks in the pathogenesis of bisphosphonate-related osteonecrosis of the jaw

OBJECTIVES

The aim of this study was to investigate the potential role of microcrack accumulation in the pathogenesis of bisphosphonate-related osteonecrosis of the jaw (ONJ) through an animal model.

MATERIALS AND METHODS

Twenty-four ovariectomized rats were randomly divided into a bisphosphonate group (n = 19) and control group (n = 5) and weekly injected with zoledronic acid and normal saline, respectively. After 6 weeks, surgical intervention was performed, and the injections were continued for eight additional weeks. Then, the animals were sacrificed, and ONJ lesions were inspected for the presence of microcracks using scanning electron microscopy. Measurements included bone dimension, number of cracks, crack length, and normalized indices; crack density (Cr.Dn) and crack surface density (Cr.S.Dn) were used for group comparison.

RESULTS

Both number of cracks and crack length in the bisphosphonate group were greater than those in the control group (P < 0.05). Of the 19 rats injected with bisphosphonates, 13 rats (68.4 %) were classified into the ONJ group. Cr.Dn and Cr.S.Dn were significantly greater in the ONJ group than in the non-ONJ group, indicating accumulation of unrepaired microcracks (P < 0.05). Seventy-two percent of microcracks in the ONJ group conformed to the defined length that was considered significant according to a previous literature (30-80 μm); whereas 12 % of microcracks in the non-ONJ group were considered significant (P < 0.05).

CONCLUSION

Accumulation of unrepaired microcracks was significantly associated with the development of bisphosphonate-related ONJ. Further research is required to determine the role of microcracks in the pathogenesis of bisphosphonate-related ONJ.

CLINICAL RELEVANCE

Long-term bisphosphonates use may deteriorate the biomechanical and physiological bone integrity, contributing to the pathogenesis of bisphosphonate-related ONJ.

Analysis of the time-to-onset of osteonecrosis of jaw with bisphosphonate treatment using the data from a spontaneous reporting system of adverse drug events

Background

Bisphosphonates (BPs) are potent antiresorptive agents used to treat osteoporosis and the complications associated with malignant bone metastasis. The aim of this study was to evaluate the incidence of bisphosphonate-related osteonecrosis of the jaw (BRONJ) using the Japanese Adverse Drug Event Report (JADER) database. In particular, we focused on the time-to-onset profile of BRONJ.

Findings

We analyzed reports of BRONJ in the JADER database and calculated the reporting odds ratio (ROR) of BPs potentially associated with BRONJ. We applied the weibull shape parameter to time-to-event data in JADER. The drugs selected for this investigation were seven BPs approved in Japan (alendronate [intraveneous, I.V.], pamidronate, and zoledronate as I.V. BPs; and alendronate (oral), etidronate, minodronate, and risedronate as oral BPs). We analyzed reports of BRONJ events associated with BPs in the JADER database from April 2004 to November 2014. The median value of BRONJ cases caused by alendronate (I.V.), pamidronate, zoledronate, alendronate (oral), etidronate, minodronate, and risedronate were 1342, 812, 486, 863, 1461, 432, and 730 days, respectively. The lower 95 % confidence interval of the Weibull-shape parameter β for I.V. BPs (pamidronate and zoledronate) exceeded 1. The risk of BRONJ with I.V. BPs increased over time.

Conclusion

Thus, the incidence of BRONJ with BP treatment should be closely monitored for a 3-year period. Further studies are required to draw conclusions, and we believe that this information about BRONJ induced by BPs will prove beneficial to patients and pharmacists.

Impact of Osteonecrosis of the Jaw on Osteoporosis Treatment in Japan: Results of a Questionnaire-Based Survey by the Adequate Treatment of Osteoporosis (A-TOP) Research Group

Dentists request a discontinuation of antiresorptive agents, such as bisphosphonate, before and after tooth extractions to prevent osteonecrosis of the jaw (ONJ). However, little is known about how this affects ONJ and osteoporosis treatment and how medical professionals and dentists cooperate to treat ONJ in patients with osteoporosis. This study aimed to clarify the impact of ONJ on osteoporosis treatment in Japan. A structured questionnaire including 14 key clinical queries was sent to 488 medical professionals as part of the Japanese Osteoporosis Intervention Trial (JOINT)-04, and 206 responses were received. A total of 173 respondents had received discontinuation requests from dentists. Of these, 28 respondents experienced 30 adverse events including ten fractures and one incidence of ONJ. The respondents who refused discontinuation requests observed no cases of ONJ. Approximately 16 % of respondents had patients who discontinued osteoporosis treatment, following a requested drug discontinuation, after tooth extraction. Dentists requested discontinuations for many medications that were not associated with the incidence of ONJ. Approximately 76 % of respondents had never requested oral health care from dentists before osteoporosis treatment and 72 % reported no cooperation between dentists and medical professionals in their region. Our results suggest that drug discontinuation may increase adverse events and disturb osteoporosis treatment without completely preventing ONJ. Currently, both medical professionals and dentists in Japan still continue to recommend their own treatment position. A forum to share information about ONJ among medical professionals, dentists, and patients is required.

Medication Related Osteonecrosis of the Jaw: 2015 Position Statement of the Korean Society for Bone and Mineral Research and the Korean Association of Oral and Maxillofacial Surgeons

Bisphosphonates are the most widely prescribed drugs for the treatment of osteoporosis, and are also used in malignant bone metastases, multiple myeloma, and Paget's disease, and provide therapeutic efficacy on those diseases. However, it was reported that occurrence of osteonecrosis of the jaw (ONJ) could be related with bisphosphonate exposures, and there have been many cases regarding this issue. Therefore, a clearer definition and treatment guidelines were needed for this disease. The American Society for Bone and Mineral Research (ASBMR) and American Association of Oral and Maxillofacial Surgeons (AAOMS) reported statements on bisphosphonate-related ONJ (BRONJ), and a revised version was recently presented. In the revised edition, the diagnosis BRONJ was changed to medication-related ONJ (MRONJ), which reflects a consideration of the fact that ONJ also occurs for denosumab, a bone resorption inhibitor of the receptor activator of nuclear factor-kappa B ligand (RANKL) antibody family, and bevacizumab, an anti-angiogenesis inhibitor. In 2009, a statement on ONJ was also reported locally by a relevant organization, which has served as basis for clinical treatment in Korea. In addition to the new official stance of the AAOMS and ASBMR, with an increasing pool of ONJ clinical experience, a revised version of the 2009 local statement is needed. As such, the Korean Society for Bone and Mineral Research (KSBMR) and the Korean Association of Oral and Maxillofacial Surgeons (KAOMS) have collectively formed a committee for the preparation of an official statement on MRONJ, and have reviewed recent local and international data to propose guidelines customized for the local Korean situation.

Perioperative discontinuation of intravenous bisphosphonate therapy reduces the incidence and severity of bisphosphonate-related osteonecrosis of the jaw: A randomized, controlled, prospective experimental study in rats

OBJECTIVE

To evaluate the effects of intravenous bisphosphonate discontinuation on incidence and severity of bisphosphonate-related osteonecrosis of the jaw (BRONJ).

MATERIAL AND METHODS

Seventy rats were randomly divided into 7 groups. In control and S0 groups, weekly injection of saline and 0.06 mg/kg zoledronate (respectively) for 4 weeks, tooth extraction, continuation of injections for 2 months and euthanasia were performed. In group S1, zolendronate injection for 4 weeks, tooth extraction, zolendronate discontinuation for 2 months, and euthanasia were done. For groups S2, S3, S4, and S5, zolendronate injections for 4 weeks, drug holiday for 1-4 months (respectively) before and 2 months after tooth extraction, and euthanasia were performed. Presence of bone exposure, osteonecrosis, and new bone formation were clinically and histologically evaluated.

RESULTS

The rate of BRONJ in control, S0, S1, S2, S3, S4, and S5 groups was 0%, 85%, 80%, 65%, 60%, 50%, and 40%, respectively. In control group, epithelial healing, bone formation, and absence of osteonecrosis; and in S0 group, unhealed epithelium, osteonecrosis, and impaired bone formation were histologically observed. In study groups, prolongation of drug holiday caused diminished osteonecrosis, and improved bone and epithelial healing.

CONCLUSION

Zolendronate discontinuation significantly decreased the incidence and severity of BRONJ in rats.

Copper accumulation in the sequestrum of medication-related osteonecrosis of the jaw

Bisphosphonates (BPs) have been widely, efficiently, and safely used for the treatment of various bone-related diseases such as osteoporosis. However, concerns about jaw osteonecrosis associated with oral treatment (medication-related osteonecrosis of the jaw [MRONJ]) have been increasing. Although many risk factors for MRONJ have been elucidated, its precise etiology and methods of prevention remain unknown. In this study, we have applied various elemental analysis methods for MRONJ specimens (e.g., X-ray fluorescence with synchrotron radiation [SR-XRF], particle-induced X-ray emission [PIXE], X-ray absorption fine structure [XAFS]) in order to reveal the accumulation and chemical state of trace bone minerals. In four MRONJ sequestra, the characteristic localization of copper (Cu) was observed by SR-XRF. Using micro-PIXE analysis, Cu looked to be localized near the edge of the trabecular bone. The chemical state of the accumulated Cu was estimated using XAFS and the possibility of a Cu–BP complex formation was assumed. Thus, in this study we argue for the feasibility of the trace element analysis to evaluate the potential pathophysiological mechanism of MRONJ.

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Characteristic localization of Cu was observed by SR-XRF in the four MRONJ sequestra.

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The accumulated Cu was suspected as Cu–bisphosphonate complex by XAFS analysis.

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The feasibility of the trace element analysis for the pathophysiological mechanism of MRONJ was suggested.

Surgical treatment of bisphosphonate-associated osteonecrosis: Prognostic score and long-term results

Over a century after the first synthesis of bisphosphonates (1897) and a decade (2003) since the initial report on bisphosphonate-related osteonecrosis of the jaw (ONJ), this osteopathy remains a serious clinical challenge. A single center longitudinal study (2005-2014) was carried out to prospectively characterize inpatients with manifest ONJ and to evaluate their outcomes. The data recorded were: medical history, bisphosphonate treatment, localization, imaging, treatment, histomorphological features, and complications. A prognostic score (modified UCONN-Score) was adopted to predict outcomes. Eighty patients were included (mean age 69.4 years; 40 male, 40 female). Breast cancer (n = 25), multiple myeloma (n = 16), and prostate cancer (n = 15) were the three most common malignancies; and cardiovascular disease (n = 31), diabetes mellitus (16), and renal disorders (6) were the most important comorbidities. The severity of ONJ was stage I in three patients, stage II in 37, and stage III in 40, being predominantly localized in the posterior mandible and needing gradual resection. The average duration of bisphosphonate treatment was 38.3 months. The typical histological aspects of ONJ were predominantly osteonecrosis, bone marrow fibrosis, and bacterial colonization (Actinomyces) with suppurative inflammation. Within the resected jawbone a primary malignancy was diagnosed in two cases. The overall success rate was 83.6% (follow-up 23.5 months), with a UCONN-Score ≥15 predicting unfavorable treatment results (OR = 5.2). The past decade has enhanced experience with ONJ treatment and knowledge about its pathogenesis, which seems to be a multistep process. This study demonstrates the importance of bone and multilayer soft tissue management, preferably as an early intervention. The UCONN-Score might help to assess individual prognosis in ONJ surgery and the potential benefit of an antiresorptive drug holiday. To our knowledge it is the first use of a prognostic score in ONJ surgery.

The Time Course Changes in Bone Metabolic Markers after Administering the Anti-Receptor Activator of Nuclear Factor-Kappa B Ligand Antibody and Drug Compliance among Patients with Osteoporosis

STUDY DESIGN

Retrospective study.

PURPOSE

We conducted a study to investigate the time course changes in bone metabolic markers after the administration of the anti-receptor activator of nuclear factor-kappa B ligand (RANKL) antibody and to assess drug compliance among osteoporotic patients.

OVERVIEW OF LITERATURE

The anti-RANKL antibody is expected to provide an improvement in those with a bone metabolism disorder. However there are only a few clinical reports available on the effect of treatment.

METHODS

We included 40 post-menopausal osteoporotic patients who received the anti-RANKL antibody. To determine the time course changes in the bone metabolic markers, we measured the serum tartrate-resistant acid phosphatase 5b (TRACP 5b; a bone resorption marker) and the serum N-terminal propeptide of type 1 collagen (P1NP; a bone formation marker) levels prior to and 1 month after administrating the anti-RANKL antibody. To evaluable drug compliance, we assessed the dropout rate during treatment and at 6 months after treatment.

RESULTS

The average TRACP 5b level significantly decreased from 574.8 mU/dL before treatment to 153.2 mU/dL 1 month after treatment (p<0.05). There was no significant difference in the average P1NP level, which was 56.9 µG/L and 35.1 µG/L before and 1 month after treatment, respectively (p>0.05). As for drug compliance, we did not have any dropouts during the treatment or after 6 months (dropout rate: 0%).

CONCLUSIONS

Our study suggests that anti-RANKL antibody treatment suppresses bone resorption and maintains bone formation.

Evaluation of dental implants as a risk factor for the development of bisphosphonate-related osteonecrosis of the jaw in breast cancer patients

It remains unclear whether dental implants are a risk factor for the development of bisphosphonate-related osteonecrosis of the jaw (BRONJ). We retrospectively evaluated the status of dental implants in patients given intravenous bisphosphonates (BPs) in a breast cancer cohort to elucidate the risk for BRONJ at the implant site. We established a BRONJ oral monitoring program for 247 breast cancer patients given intravenous BP in our institution. The 3-year cumulative incidence rate was determined. The systemic and local risk factors of 44 patients who completed comprehensive oral examinations were evaluated by logistic regression analysis. The 3-year cumulative incidence rate of the 247 patients was 0.074 % (8/247, 95 % CI 0.0081-0.014). In the 44 orally examined patients, 6 (13.6 %: 6/44) had dental implants. Of these 6 patients, 1 developed BRONJ at the implant site. There were no significant differences in the age, total BP treatment period, number of residual teeth, time of regular oral monitoring, oral hygiene level, or dental implant insertion. Although a case of ONJ was identified, dental implants which were inserted before intravenous BP administration were not a risk factor for the development of ONJ in breast cancer patients.

The incidence of and risk factors for developing atypical femoral fractures in Japan

The long-term treatment with anti-resorptive drugs for osteoporotic patients is suggested to be associated with an increase in atypical femoral fractures (AFFs). However, their incidence, patient characteristics, and risk factors have not been fully elucidated especially in Asian countries. This retrospective observational cohort study found fourteen AFFs in ten patients (four bilateral fractures) among 2,238 hip and femoral shaft fractures treated in our associated hospitals between 2005 and 2010; this incidence (0.63%) was similar to Caucasians. Of the ten patients with AFFs, nine (90%) and six (60%) were using bisphosphonates (BPs) and glucocorticoids (GCs), respectively, compared to 14.3 and 8.6% for patients with typical femoral fractures who were using these agents. As comorbid conditions, five patients had collagen disease (CD) and two had diabetes. A fracture location-, age- and gender-matched (1:3) case-control study revealed that administration of BPs, GCs, and suffering from collagen disease (CD) were significant risk factors for developing AFFs [odds ratios 36.0 (95% confidence intervals 3.8-342.2), 13.0 (2.3-74.1) and 9.0 (1.6-50.3), respectively]. Interestingly, all of the patients with atypical subtrochanteric femoral fractures, defined as those within 5 cm of the lesser trochanter, were taking GCs due to CD, and the age of these patients (average of 54.8 years) was significantly younger than those with atypical diaphyseal femoral fractures (average of 77.2 years, p < 0.05). In conclusion, the incidence of AFFs in the Japanese population was similar to that of Caucasians, and taking BPs and GCs and suffering from CD were risk factors for developing AFFs.

Comparison of the prognosis of bisphosphonate-related osteonecrosis of the jaw caused by oral and intravenous bisphosphonates

Bisphosphonates (BPs) have been used in medical practice for the treatment of osteoporosis, bone metastasis, and multiple myeloma. Although many studies have been published, the treatment and prognosis of bisphosphonate-related osteonecrosis of the jaw (BRONJ) remain unclear. This study included 59 patients with BRONJ: 29 had taken oral BPs and 30 had taken intravenous (IV) BPs. All received conservative treatments. When separated sequestra were seen, a sequestrectomy was performed. Segmental mandibular resection was performed when pathological fractures were diagnosed. The outcomes of treatments were compared between groups. For patients treated with oral rinses or mandibular resection, the number in whom clinical healing was observed did not differ between the oral BP and IV BP groups. With regard to sequestrectomy, 94% of patients in the oral BP group showed improvement with this treatment compared to 50% in the IV BP group. The number of patients in whom clinical healing of BRONJ was achieved was statistically better in the oral BP group than in the IV BP group after 6 months of treatment (P<0.001). The results showed that >90% of patients treated with oral BPs could be cured. However, 50% of patients treated with IV BPs did not show an improvement. Additional research is needed to further increase the therapeutic efficacy for the resolution of BRONJ.