Nationwide survey for bisphosphonate-related osteonecrosis of the jaws in Japan

What Affects Healing Rates in Patients Treated for Medication-Related Osteonecrosis of the Jaw? The Role of Operative Therapy and Other Clinical Factors

BACKGROUND

In the therapy of medication-related osteonecrosis of the jaw (MRONJ), the healing rate, effectiveness of operative therapy, and factors associated with healing remain unclear.

PURPOSE

This study aimed to estimate MRONJ therapy healing rates and identify associated prognostic factors.

STUDY DESIGN, SETTING, SAMPLE

A 25-center prospective cohort study was conducted on 291 patients with MRONJ treated with a common therapeutic protocol during 2013-2016. Patients unable to continue examinations or treatment were excluded.

PREDICTOR VARIABLE

The primary predictor variable was MRONJ therapy grouped into two categories: operative and nonoperative. Secondarily, the prognostic factors categorized as demographic, medical, clinical, and perioperative were evaluated.

MAIN OUTCOME VARIABLES

The primary outcome variable was treatment duration, defined as the time (in months) between the initiation of therapy and when the site was healed or the date of the final visit or loss to follow-up.

COVARIATES

Not applicable.

ANALYSES

Descriptive statistics and 3-year cumulative healing rates were calculated. The association between clinical factors and time to healing was analyzed using bivariate and multivariate analyses and propensity score analysis. P < .05 was considered significant.

RESULTS

We analyzed data from 291 subjects with 76 (26.1%) and 215 (73.9%) subjects in the operative and nonoperative therapy groups, respectively. The healing rates for operative and nonoperative therapies were 95.8 and 70.7%, respectively (hazard ratio [HR] = 1.6, 95% confidence interval [CI] = 1.1-2.2, P value [P] < .01). The healing rates in patients for whom anti-resorptive agent (ARA) treatment was discontinued and continued were 87.2 and 37.4%, respectively (HR = 1.8, 95% CI = 1.1-3.0, P = .02). In a multiple regression analysis using ARA indication, the therapy method showed a significant association in the MRONJ malignancy group (HR = 2.75, 95% CI = 1.46-5.17, P < .01).

CONCLUSION AND RELEVANCE

Operative therapy and ARA discontinuation were associated with better healing rates in MRONJ therapy. However, the choice of therapy for MRONJ should be based on a comprehensive consideration of the patient's condition. ARA discontinuation should be considered an adjunctive measure because of the possibility of adverse events such as fragility fractures and skeletal related events.

[Oral mesenchymal cells, a specific niche, from development to regeneration]

Oral buccal tissues, including bone and mucosa, have unique properties. Oral mucosal fibroblasts and jaw osteoblasts, both derived from Cranial Neural Crest cells, play a key role in healing and repair. These cells express a specific repertoire of genes with their regenerative properties, but also craniofacial diseases. Understanding these tissues holds clinical promise for tissue regeneration and repair of bone and mucosal defects. These multidisciplinary advances also offer potential for better management of periodontal-related conditions and improved oral health.

Zoledronate and osteonecrosis of the jaw in osteoporosis: incidence and risk factors. Analysis of the French Pharmacovigilance Database

INTRODUCTION

Bisphosphonate-related osteonecrosis of the jaw (BRONJ) have been characterized with the use of oral bisphosphonates in osteoporosis and zoledronate in oncology. Uncertainties remain, though, with the occurrence of BRONJ related to the use of zoledronate in osteoporosis.

OBJECTIVES

We aimed to estimate the incidence and characterize the risk factors of zoledronate-associated BRONJ in osteoporosis as compared with oral bisphosphonates in real life setting.

METHODS

Cases of BRONJ associated with zoledronate, alendronate or risedronate were extracted from the French pharmacovigilance database up to 2020. The incidence of BRONJ was estimated as their respective numbers related to cases of BRONJ in patients treated with bisphosphonates for osteoporosis, over the same period, according to the Medic'AM database.

RESULTS

Between 2011 and 2020, BRONJ incidence with zoledronate was 9.6/100,000 patient-year (PY), significantly higher than with alendronate (5.1/100,000 PY, P<0.001), and risedronate (2.0/100,000 PY, P<0.001). The number of patients treated with bisphosphonates has steadily decreased by 44.5% over 10 years. Meanwhile, the incidence of BRONJ decreased (5.8/100,000 PY in 2011; 1.5/100,000 in 2020), although a rebound was observed in 2018, including 47.6% of BRONJ following denosumab. Apart from classical risk factors, recent dental cares stood out in more than 40% of BRONJ, and zoledronate had a shorter exposure time than oral bisphosphonates.

CONCLUSIONS

In a real-life setting, our data confirm that zoledronate-associated BRONJ in osteoporosis is scarce, seeming slightly more common compared with oral bisphosphonates. We also raise awareness of dental care guidelines and greater vigilance when using bisphosphonates in patients with previous exposure to denosumab.

Prevention and management of drug-induced osteonecrosis of the jaws using platelet-rich fibrin: A clinical feasibility study

OBJECTIVE

Although a standard treatment guideline has not been established to date, various treatment modalities have been described in the literature based on the staging of medication-related osteonecrosis of the jaw (MRONJ). The aim of this case series was to describe the outcomes of surgical intervention of MRONJ cases with the adjunctive use of platelet-rich fibrin (PRF).

MATERIALS AND METHODS

Thirteen patients under therapy with zoledronic acid, seven of them underwent surgical removal of necrotic bone with debridement, followed by placement of three to four PRF membranes and achieving primary closure. In six patients, PRF was used preventively to avoid MRONJ.

RESULTS

The surgical treatment outcomes were successful in all patients, with a follow-up range of 12-48 months. In the presented cases, the intraoral evaluation showed excellent soft tissue healing except for one patient secondary wound healing was reported. Additionally, there was no recurrence of bone exposure in all cases. PRF membranes were comparatively effective in postsurgical pain control.

CONCLUSION

The use of PRF could represent a valuable adjunct in the surgical management for advanced stages of MRONJ cases.

CLINICAL RELEVANCE

This clinical case series describes the use of PRF membranes as a valuable adjunct in the surgical management of MRONJ patients, especially when treating advanced MRONJ cases. Moreover, PRF demonstrates usefulness in preventing such difficult complications from occurring.

MicroRNA in medication related osteonecrosis of the jaw: a review

Medication related osteonecrosis of the jaw (MRONJ) is a condition caused by inhibition of the osteoclast activity by the anti-resorptive and anti-angiogenic drugs. Clinically, there is an exposure of the necrotic bone or a fistula which fails to heal for more than 8 weeks. The adjacent soft tissue is inflamed and pus may be present as a result of the secondary infection. To date, there is no consistent biomarker that could aid in the diagnosis of the disease. The aim of this review was to explore the literature on the microRNAs (miRNAs) related to medication related osteonecrosis of the jaw, and to describe the role of each miRNA as a biomarker for diagnostic purpose and others. Its role in therapeutics was also searched. It was shown that miR-21, miR-23a, and miR-145 were significantly different in a study involving multiple myeloma patients as well as in a human-animal study while miR-23a-3p and miR-23b-3p were 12- to 14-fold upregulated compared to the control group in an animal study. The role of the microRNAs in these studies were for diagnostics, predictor of progress of MRONJ and pathogenesis. Apart from its potential diagnostics role, microRNAs have been shown to be bone resorption regulator through miR-21, miR-23a and miR-145 and this could be utilized therapeutically.

Low-level laser therapy prevents medication-related osteonecrosis of the jaw-like lesions via IL-1RA-mediated primary gingival wound healing

BACKGROUND

Medication-related osteonecrosis of the jaw (MRONJ) is a serious debilitating disease caused by anti-resorption and anti-angiogenesis drugs, significantly affecting patients' quality of life. Recent studies suggested that primary gingival wound healing may effectively prevent the development of MRONJ. This study aimed to evaluate the effects of low-level light therapy (LLLT) on promoting gingival wound healing in extraction sockets of MRONJ-like mice and preventing the occurrence of MRONJ. Furthermore, we explored underlying mechanisms.

METHODS

Mice were randomly divided into the Ctrl, Zol, and Zol + LLLT groups. Administration of zoledronate and tooth extraction of bilateral maxillary second molars were used to build the MRONJ model, and LLLT was locally administered into the tooth sockets to examine the effect of LLLT. Next, to explore the function of IL-1RA, we performed LLLT with interleukin-1 receptor antagonist (IL-1RA) neutralizing antibody (named Zol + LLLT + IL-1RA NAb group) or negative control antibodies for tooth extraction in subsequent rescue animal experiments. Stereoscope observations, micro-computed tomography, and histological examination were conducted to evaluate gingival wound healing and bone regeneration in tooth sockets. The effects of LLLT on the migration capacities of zoledronate-treated epithelial cells were assessed in vitro.

RESULTS

LLLT promoted primary gingival wound healing without exposed necrotic bone. Micro-computed tomography results showed higher bone volume and mineral density of the tooth sockets after LLLT. Histology analysis showed complete gingival coverage, obvious bone regeneration, and reduced soft tissue inflammation, with down-regulated pro-inflammation cytokines, like interleukin-1 beta (IL-1β) and tumor necrosis factor-α (TNF-α), and up-regulated IL-1RA expression in the gingival tissue in the LLLT group. The rescue assay further showed that the effects of LLLT promoting gingival wound healing and preventing MRONJ might be partially abolished by IL-1RA neutralizing antibodies. In vitro studies demonstrated that LLLT accelerated zoledronate-treated epithelial cell migration.

CONCLUSIONS

LLLT might promote primary gingival wound healing and contribute to subsequent bone regeneration of the tooth extractions in MRONJ-like lesions via IL-1RA-mediated pro-inflammation signaling suppression.

Management of bisphosphonate preparation-treated children in the field of pediatric dentistry

Since most of the reports of BRONJ onset are adults, in order to clarify the current situation of BRONJ onset in children, it is necessary to search for articles and report on the current status and actual conditions of surgical treatment of children with BP preparations who are being followed up in our clinic. In previous reports both inside and outside Japan, there was no mention of jaw bone necrosis during tooth extraction or surgery in children who were receiving or had a history of BP administration. There were 15 children with a history of BP administration who manage the oral cavity in our clinic. No unpleasant events in the extraction of deciduous teeth were confirmed in medical records. It is necessary to intervene early on oral management of pediatric BP-administered children, especially BP-and steroid-administered children, obtain plaque control to keep the oral cavity cleaner, respond early to infectious diseases, and manage to prevent inflammation from spreading to the jawbone. When surgical treatment is unavoidable, it is important to consider reducing the invasion as much as possible and to cooperate with the medical department such as administration of antibiotics to prevent infection.

Influence of alcohol sensitivity on bone metastases and skeletal-related events in primary operable breast cancer: A retrospective cohort study

Background

Bone metastases in breast cancer patients are a common concern for medical doctors and dentists. Bone-modifying agents, which are necessary to prevent skeletal-related events (SREs), are associated with osteonecrosis of the jaw as an adverse side effect. Hypersensitivity to alcohol is an unfavorable response caused by deficiency of aldehyde dehydrogenase-2 (ALDH2) activity. Inactive ALDH2 is associated with osteoporosis, but its influence on bone metastases is unclear. The aim of our study was to evaluate the effects of alcohol sensitivity on bone metastases and SREs in primary operable breast cancer patients.

Methods

We retrospectively analyzed patients who were administered docetaxel, an anti-tumor agent, for histologically diagnosed breast cancer between April 2004 and September 2015. Alcohol sensitivity was assessed based on medical records of hypersensitivity to alcohol. The primary endpoint was time to bone metastases and the secondary endpoint was time to first SRE from the initial docetaxel administration. Data were stratified by alcohol sensitivity and tumor stages, and differences were estimated by the Kaplan-Meier method. Prognostic risk factors were analyzed by the multivariate Cox proportional hazards model.

Results

The median follow-up period of patients with high sensitivity to alcohol (n = 45) was 54 months and that for those with low sensitivity (n = 287) was 64 months. Stratification by alcohol sensitivity revealed that tumor stage exhibited significant correlations with the cumulative incidence of bone metastases in low-sensitivity patients; however, no differences were found in high-sensitivity patients. In multivariate analysis, alcohol sensitivity was a significant prognostic risk factor for bone metastases (HR 2.721, 95% CI 1.268–5.841, P = 0.010).

Conclusion

Alcohol sensitivity may be a prognostic risk factor for bone metastases. More detailed genetic investigations and metabolic analyses are needed.

A comparative study of the clinical characteristics of patients with medication-related osteonecrosis of the jaw and osteoporosis or malignancy

OBJECTIVE

This study aimed to compare the clinical characteristics of patients with medication-related osteonecrosis of the jaw (MRONJ) and osteoporosis vs malignancy.

STUDY DESIGN

The study included patients hospitalized with MRONJ between July 2013 and April 2021. These patients were assigned to the osteoporosis or malignancy groups according to their primary disease. Characteristics and clinical variables were recorded and compared.

RESULTS

Nighty-one patients (107 MRONJ lesions) were included, with 12 (14 lesions) in the osteoporosis group and 79 (93 lesions) in the malignancy group. The osteoporosis and malignancy groups differed in their respective incubation periods (57.0 ± 42.8 vs 29.3 ± 19.8 months, respectively; P = .048), bisphosphonates cumulative dose (16,487.4 ± 14,268.8 mg alendronate vs 104.0 ± 79.9 mg zoledronic; P = .014), and rate of patients receiving antiangiogenic agents (0/12, 0.0% vs 48/79, 60.8%; P = .001). The groups were similar in their treatment outcomes, measured as successful surgeries (11/12, 91.7% vs 59/79, 74.7%; P = .351).

CONCLUSIONS

For stage 2 or 3 MRONJ, patients with osteoporosis (exposed to oral bisphosphonates) developed MRONJ over a longer incubation period than patients with malignancy. The groups had similar responses to surgery.

Osteonecrosis of the Jaw and Antiresorptive Agents in Benign and Malignant Diseases: A Critical Review Organized by the ECTS

CONTEXT

Antiresorptive therapy significantly reduces fracture risk in patients with benign bone disease and skeletal-related events (SREs) in patients with bone metastases (BM). Osteonecrosis of the jaw (ONJ) is a rare but severe condition manifested as necrotic bone lesion or lesions of the jaws. ONJ has been linked to the use of potent antiresorptive agents, termed medication-related ONJ (MRONJ).

OBJECTIVE

We aimed to identify the differences various aspects of MRONJ among distinct patient categories and provide recommendations on how to mitigate the risk and optimally manage MRONJ in each of them.

METHODS

A working group of the European Calcified Tissue Society (ECTS) and 2 experts performed an updated detailed review of existing literature on MRONJ incidence, characteristics, and treatment applied in bone diseases with variable severity of skeletal insult, ranging from osteoporosis to prevention of cancer treatment-induced bone loss and SREs in cancer patients with BM.

RESULTS

The risk for MRONJ is much higher in patients with advanced malignancies compared to those with benign bone diseases because of the higher doses and more frequent administration of antiresorptive agents in individuals with compromised general health, along with coadministration of other medications that predispose to MRONJ. The overall risk for MRONJ is considerably lower than the benefits in all categories of patients.

CONCLUSION

The risk for MRONJ largely depends on the underlying bone disease and the relevant antiresorptive regimen applied. Physicians and dentists should keep in mind that the benefits of antiresorptive therapy far outweigh the risk for MRONJ development.

Long-term safety of eldecalcitol in Japanese patients with osteoporosis: a retrospective, large-scale database study

INTRODUCTION

This real-world study evaluated whether long-term use of eldecalcitol (ELD) increases the risk of adverse events (AEs), namely, hypercalcemia, acute kidney injury (AKI), and urolithiasis, and analyzed the ELD-induced risk of rare AEs such as osteonecrosis of the jaw (ONJ) and atypical femoral fracture (AFF).

MATERIALS AND METHODS

Patient records were retrieved from Medical Data Vision (MDV) and Japan Medical Data Center (JMDC) databases. The ELD-treated osteoporosis patient cohort (ELD cohort) was analyzed to determine the incidence rate of the aforementioned AEs. The patient cohort that was prescribed active vitamin D₃ other than ELD (AVD cohort) was analyzed as the reference.

RESULTS

Incidence rates of hypercalcemia, AKI, and urolithiasis in the ELD cohort were 0.942, 0.517, 2.465 events per 100 person-years, respectively, in the MDV dataset, and 0.687, 0.155, 3.785, respectively, in the JMDC dataset. The incidence rates of these AEs in the ELD cohort remained relatively constant throughout ELD treatment. A small number of patients experienced ONJ or AFF during ELD or AVD treatment. The number of ONJ and AFF cases in the both cohorts decreased over time. The two cohorts showed no difference in the concomitant use of anti-bone resorptive agents such as bisphosphonates and denosumab.

CONCLUSION

The risk of hypercalcemia and AKI associated with ELD use observed in this retrospective analysis is similar to that reported previously in the Japanese post-marketing surveillance of ELD. Furthermore, ELD, similar to AVD, may not increase the risk of ONJ and AFF.

Medication Related Osteonecrosis of the Jaw: 2021 Position Statement of the Korean Society for Bone and Mineral Research and the Korean Association of Oral and Maxillofacial Surgeons

Antiresorptives are the most widely prescribed drugs for the treatment of osteoporosis. They 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 the occurrence of osteonecrosis of the jaw (ONJ) could be related to antiresorptive 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 and the Amnerican Association of Oral and Maxillofacial Surgeons 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 consideration of the fact that ONJ also occurs for denosumab, a bone resorption inhibitor of the receptor activator of the nuclear factor-κB ligand antibody family, and bevacizumab, an anti-angiogenesis inhibitor. The Korean Society for Bone and Mineral Research and the Korean Association of Oral and Maxillofacial Surgeons had collectively formed a task force for the preparation of an official statement on MRONJ based on a previous position paper in 2015. The task force reviewed current knowledge and coordinated dental and medical opinions to propose the guideline customized for the local Korean situation.

Local administration of ReveromycinA ointment suppressed alveolar bone loss in mice

ReveromycinA (RMA) was developed and is a unique agent for inhibiting osteoclast activity. In a previous study, we experimentally induced periodontal disease in a high-turnover osteoporosis osteoprotegerin-knockout mice (OPG KO) model and found that intraperitoneal administration of RMA inhibited alveolar bone resorption. We prepared a novel RMA-containing ointment for topical non-invasive administration in the oral cavity, in preparation for possible future clinical application. And we investigated whether this ointment can inhibit alveolar bone resorption in an experimental mouse model of periodontal disease. We examined wild-type (WT) and OPG KO mice ligated with wire around contact points on the left first and second molars to cause food impaction and induce experimental periodontal disease. RMA was administered three times a day. Using micro-computed tomography, we measured the volume of alveolar bone loss and also performed histological analysis. Our findings showed that localized administration of RMA containing ointment resulted in suppressed alveolar bone resorption, reduced osteoclast count, and lower immunostaining scores of inflammation sites compared with controls in both OPG KO and WT mice. Localized application of the specific osteoclast suppressor RMA in ointment form in the oral cavity could be a novel treatment for periodontitis that inhibits alveolar bone resorption locally.

Nitrogen-containing bisphosphonates and lipopolysaccharide mutually augment inflammation via adenosine triphosphate (ATP)-mediated and interleukin 1β (IL-1β)-mediated production of neutrophil extracellular traps (NETs)

Among the bisphosphonates (BPs), nitrogen-containing BPs (N-BPs) have much stronger anti-bone-resorptive actions than non-N-BPs. However, N-BPs have various side effects such as acute influenza-like reactions after their initial administration and osteonecrosis of the jawbones after repeated administration. The mechanisms underlying such effects remain unclear. To overcome these problems, it is important to profile the inflammatory nature of N-BPs. Here, we analyzed the inflammatory reactions induced in mouse ear pinnae by the N-BPs alendronate (Ale) and zoledronate (Zol). We found the following: (i) Ale and Zol each induced two phases of inflammation (early weak and late strong ear swelling); (ii) both phases were augmented by lipopolysaccharides (LPSs; cell-surface constituent of gram-negative bacteria, including oral bacteria), but prevented by inhibitors of the phosphate transporters of solute carrier 20/34 (SLC20/SLC34); (iii) macrophages and neutrophils were involved in both phases of Ale+LPS-induced ear-swelling; (iv) Ale increased or tended to increase various cytokines, and LPS augmented these effects, especially that on interleukin 1β (IL-1β); (v) adenosine triphosphate (ATP) was involved in both phases, and Ale alone or Ale+LPS increased ATP in ear pinnae; (vi) the augmented late-phase swelling induced by Ale+LPS depended on both IL-1 and neutrophil extracellular traps (NETs; neutrophil-derived net-like complexes); (vii) neutrophils, together with macrophages and dendritic cells, also functioned as IL-1β-producing cells, and upon stimulation with IL-1β, neutrophils produced NETs; (viii) stimulation of the purinergic 2X7 (P2X7) receptors by ATP induced IL-1β in ear pinnae; (ix) NET formation by Ale+LPS was confirmed in gingiva, too. These results suggest that (i) N-BPs induce both early-phase and late-phase inflammation via ATP-production and P2X7 receptor stimulation; (ii) N-BPs and LPS induce mutually augmenting responses both early and late phases via ATP-mediated IL-1β production by neutrophils, macrophages, and/or dendritic cells; and (iii) NET production by IL-1β-stimulated neutrophils may mediate the late phase, leading to prolonged inflammation. These results are discussed in relation to the side effects seen in patients treated with N-BPs. © 2021 American Society for Bone and Mineral Research (ASBMR).

Characteristics of patients with osteonecrosis of the jaw with oral versus intravenous bisphosphonate treatment

PURPOSE

This retrospective study was aimed to evaluate the clinical characteristics and treatment outcomes in patients with osteonecrosis of the jaw who were receiving oral versus intravenous (IV) bisphosphonate (BP).

MATERIALS AND METHODS

This retrospective study enrolled subjects who had been diagnosed with medication-related osteonecrosis of the jaw (MRONJ) during the period from July 2010 to June 2014. Information regarding the following demographic and clinical characteristics was collected: demographic data, administration route and type of BP, duration of BP medication, primary disease, number of involved sites, location of the lesion, number of surgeries, outcome of treatments, and laboratory test. All the patients were divided into oral and IV BP groups; and the between-group differences were compared.

RESULTS

Total 278 patients were divided into two groups as per the route of BP administration. The proportion of oral BP-related MRONJ group were more dominant over IV BP group (oral BP, n = 251; IV BP, n = 27). In the IV BP group, the average dosing duration (31.4 months) was significantly shorter than that in the oral BP group (53.1 months) (P < 0.001). The average number of involved sites in the oral BP group (1.21 ± 0.48) was smaller than that in the IV BP group (1.63 ± 0.84) (P < 0.001). The average number of surgeries was higher in the IV BP group (1.65 ± 0.95) as compared to that in the oral BP group (0.98 ± 0.73) (P < 0.001). Outcome after the surgery for MRONJ after IV BP was poor than oral BP group.

CONCLUSION

IV administration of BP causes greater inhibition of bone remodeling and could lead more severe inflammation. Therefore, even if the duration of IV administration of BP is shorter than that of oral BP, the extent of the lesion could be more extensive. Therefore, the result suggests that the MRONJ after IV BP for cancer patients needs to be considered as different characteristics to oral BP group for osteoporosis patents.

A 3-year postmarketing study on the safety and effectiveness of once-monthly risedronate in Japanese patients with osteoporosis

Objectives

This postmarketing study aims to evaluate the safety and effectiveness of oral administration of risedronate at 75 mg once monthly for 36 months in patients with osteoporosis in Japan.

Methods

Participants were ambulatory outpatients with osteoporosis who were ≥ 50 years old and had prevalent vertebral fractures. Outcomes were the incidence rate of adverse drug reaction (ADR), cumulative incidence of vertebral, nonvertebral, and hip fractures, the percent changes of lumbar spinal L_2–4 bone mineral density (BMD), and low back pain. In addition, medication compliance was examined.

Results

Safety, vertebral fractures, and other outcomes were analyzed in 542, 328, and 535 patients, respectively. In the safety analysis set, 88.38% of the patients were women and the mean age was 75.9 years. The monthly medication compliance rate ranged from 83.24% to 95.38%. The incidence rate of ADRs, including 4 severe ADRs, was 10.52% (n = 57). The common ADRs were gastrointestinal disorders, musculoskeletal, and connective tissue disorders. No osteonecrosis of the jaw was reported. The cumulative incidences (95% CI) of vertebral, nonvertebral, and hip fractures at 36 months were 12.58% (8.61–18.18), 6.59% (4.31–10.01), and 1.58% (0.64–3.88), respectively. The L_2–4 BMD increased by 10.59% compared with baseline value (P < 0.01), and the proportion of patients with low back pain decreased to 30.77%, at 36 months.

Conclusions

Administering 75 mg of risedronate once a month remains a favorable compliance rate and may be useful for the treatment of patients, even the elderly, with osteoporosis in daily practice.

Evaluation of segmental mandibular resection without microvascular reconstruction in patients affected by medication-related osteonecrosis of the jaw: a systematic review

Medication-related osteonecrosis of the jaw (MRONJ) is a severe condition that affects the jaw in patients exposed to specific drugs. More often it has been described in association with bisphosphonates (BP), but nowadays it has been observed with the use of other medications, such as denosumab (a RANK ligand inhibitor and monoclonal antibody agent) and antiangiogenic drugs. Managing the condition has unfortunately proven difficult and still remains a major challenge for clinicians and surgeons. The aim of this systematic review was to identify and analyse the evidence on mandibular segmental resection in patients with advanced MRONJ. A multi-database (PubMed, MEDLINE, EMBASE, CINAHL, and Cochrane Central Register of Controlled Trials) systematic search was performed. Any type of study on human patients treated with antiresorptive and antiangiogenic drugs was considered. The primary aim was to understand the success of mandibular segmental resection in the short, medium, and long term, and to understand its effects before, during, and after the operation. The search yielded 11 studies that were eligible for analysis with a total of 67 patients. Of the 11 studies, seven reported no complications, and overall, postoperative complications were seen in 16 cases. Recurrence of osteonecrosis was reported in one study. The most common postoperative complication was removal of hardware (n = 11). The mean (SD) follow-up time for eight studies was 35.57 (17.73) months. According to the limited data available in the literature, mandibular segmental resection is a viable treatment that has been used successfully in patients with various stages of MRONJ. The data show a relatively high percentage of recurrence. Additional data based on a larger cohort of patients or case-control studies are necessary to justify routine use of this type of intervention in patients affected by the condition.

Comprehensive Study of the Risk Factors for Medication-Related Osteonecrosis of the Jaw Based on the Japanese Adverse Drug Event Report Database

Medication-related osteonecrosis of the jaw (MRONJ) is associated with many drugs, including bisphosphonates (BPs). BPs are associated with atypical femoral fractures and osteonecrosis of the external auditory canal. Thus, many drugs are reported to cause adverse effects on bone. This study aimed to investigate the effects of drugs and patient backgrounds regarding osteonecrosis-related side effects, including MRONJ. This study used a large voluntary reporting database, namely, the Japanese Adverse Drug Event Report database. First, we searched for risk factors related to MRONJ using volcano plots and logistic regression analysis. Next, we searched for bone-necrosis-related side effects using principal component and cluster analysis. Factors that were significantly associated with MRONJ included eight types of BPs and denosumab, prednisolone, sunitinib, eldecalcitol, raloxifene, letrozole, doxifluridine, exemestane, radium chloride, medroxyprogesterone, female, elderly, and short stature. Furthermore, antiresorptive agents (i.e., BPs and denosumab) tended to induce MRONJ and atypical femoral fractures by affecting osteoclasts. We believe these findings will help medical personnel manage the side effects of many medications.

Treatment outcomes of adjunctive teriparatide therapy for medication-related osteonecrosis of the jaw (MRONJ): A multicenter retrospective analysis in Japan

BACKGROUND

Therapeutic strategies for patients with medication-related osteonecrosis of the jaw (MRONJ) remain controversial. The aim of the present study was to clarify the effectiveness and safety of teriparatide therapy in Japanese MRONJ patients based on a large number of case series with a multicenter retrospective analysis.

PATIENTS AND METHODS

Between January 2012 and December 2016, 29 patients who were diagnosed with MRONJ at 10 hospitals were treated with teriparatide. The medical records of these patients were retrospectively reviewed to assess the efficacy and safety of teriparatide therapy for MRONJ patients.

RESULTS

Adverse events occurred in 17.2% of patients (5/29). One patient developed severe arthralgia and discontinued teriparatide therapy after 12 days, while others continued the treatment. Among 29 patients, the median period of administration of teriparatide was 14.0 months (range, 0.3-26 months), and treatment outcomes were evaluated as effective in 75.9% of patients with complete resolution in 65.5%. Among patients treated with oral bisphosphonates (BPs), 83.3% were effectively treated with teriparatide and 40% with intravenous BPs. The oral administration of BPs was associated with successful treatment outcomes with teriparatide (p = 0.062).

CONCLUSIONS

Teriparatide therapy has potential as an effective treatment option for MRONJ.

Pharmacogenomics of osteonecrosis of the jaw

Osteonecrosis of the jaw (ONJ) is a rare but serious drug induced adverse event, mainly associated with the use of antiresorptive medications, such as intravenous (IV) bisphosphonates (BPs) in cancer patients. In this review, we evaluated all the pharmacogenomic association studies for ONJ published up to December 2018. To date, two SNPs (CYP2C8 rs1934951 and RBMS3 rs17024608) were identified to be associated with ONJ by two genome-wide association studies (GWAS). However, all six subsequent candidate gene studies failed to replicate these results. In addition, six discovery candidate gene studies tried to identify the genetic markers in several genes associated with bone remodeling, bone mineral density, or osteoporosis. After evaluating the results of these 6 studies, none of the SNPs was significantly associated with ONJ. Recently, two whole-exome sequencing (WES) analysis (including one from our group) were performed to identify variants associated with ONJ. So far, only our study successfully replicated discovery result indicating SIRT1 SNP rs7896005 to be associated with ONJ. However, this SNP also did not reach genome-wide significance. The major limitations of these studies include lack of replication phases and limited sample sizes. Even though some studies had larger sample sizes, they recruited healthy individuals as controls, not subjects treated with BPs. We conclude that a GWAS with a larger sample size followed by replication phase will be needed to fully investigate the pharmacogenomic markers of ONJ.

Novel insight into the management of bisphosphonate-related osteonecrosis of the jaw (BRONJ)

Bisphosphonate-related osteonecrosis of the jaw (BRONJ), characterized by refractory bone exposure, has recently emerged as a serious side effect of bisphosphonate (BPs) treatment. We discuss novel insights that may help to improve the efficacy of BRONJ treatment and prevention. Our report highlights the following: (1) The presence of exposed bone in patients taking BPs does not necessarily reflect BRONJ, and diagnoses of oral ulceration with bone sequestration and malignancy must be excluded. (2) Osteonecrosis type of BRONJ is difficult to avoid using preventive dental measures alone. However, as with osteomyelitis type of BRONJ, preventive dental measures are indispensable for reducing the risk of secondary infection and disease progression. (3) The importance of tooth extraction as a risk factor for BRONJ among patients taking BPs has been overstated, particularly when they are administered at low doses. Delaying tooth extraction may increase the risk for the onset and progression of osteomyelitic BRONJ. (4) In patients taking low doses of BPs, dental implant surgery is not necessarily contraindicated if there are no other risk factors, such as combined use of corticosteroids or concomitant diabetes. However, the risk of BRONJ due to peri-implantitis must be explained when obtaining patient consent.

Imaging modalities for drug-related osteonecrosis of the jaw (2), Overview of the position paper on medication-related osteonecrosis of the jaw and the current status of the MRONJ in Japan

Since Marx reported on osteonecrosis of the jaw caused by the injectable bisphosphonates (BPs) pamidronate and zoledronate, there have been numerous reports not only in Western countries, but in Japan as well, of bisphosphonate-related osteonecrosis of the jaw (BRONJ) as a pathology similar to radiation-related osteonecrosis/osteomyelitis of the jaw, which is accompanied by exposure of the bone. Osteonecrosis of the jaw similar to that occurring with BPs is also produced with the anti-receptor activator of nuclear factor kappa-Β ligand (RANKL) antibody denosumab, a bone resorption inhibitor that has a different mode of action from BPs, and there is also a report of osteonecrosis of the jaw related to bevacizumab, an angiogenic inhibitor. Because of this, in its newest position paper (2014), the AAOMS changed the nomenclature from BRONJ to “medication-related osteonecrosis of the jaw” (MRONJ). This article presents an overview of the position paper on medication-related osteonecrosis of the jaw and the current status of the MRONJ in Japan.

Antiresorptive Agent-Related Osteonecrosis of the Jaw (ARONJ): A Twist of Fate in the Bone

Bisphosphonates (BPs) have been used as antiresorptive agents to treat patients with osteoporosis or metastatic bone cancer, each of which is characterized by bone loss due to the increased bone resorption. However, BPs could cause osteonecrosis of the jaw (ONJ), known as bisphosphonate-related osteonecrosis of the jaw (BRONJ). ONJ is associated with severe pain and deteriorated quality of life. ONJ is also caused by administration of denosumab, a monoclonal antibody against receptor activator of NFκB ligand (RANKL), that functions as a powerful antiresorptive agent. Accordingly, antiresorptive agent-related ONJ (ARONJ) has been advocated, the incidence of which is continuing to increase in Japan as a super-aging society. Importantly, the jawbone is more susceptible to infection compared with bones in other parts of the body, due to the unique anatomical and physiological characteristics; for example, the jawbone with a high remodeling rate is stimulated by teeth during mastication. The risk factors of ARONJ include dental infection, poor occlusal or oral hygiene status, and bone-invasive dental treatment, such as tooth extraction, dental implants, and dentures. Proper collaboration between doctors and dentists is of utmost importance to understand the current status of ARONJ and prevent developing ARONJ. It is also important to ensure that the patients treated with BPs or denosumab can receive appropriate dental treatment. More recently, angiogenesis inhibitors were reported to cause ONJ; thus, medication-related ONJ (MRONJ) has been advocated. This article overviews the concept of MRONJ by focusing on antiresorptive agents and the status of BRONJ in Japan.

[Current situation and future issues of antiresorptive agent-related osteonecrosis of the jaw]

Bisphosphonate-related osteonecrosis of the jaw (BRONJ), which is characterized by refractory bone exposure, has recently emerged as a serious side effect of bisphosphonate (BP) treatment. BRONJ was first thought to be due to administration of high doses of intravenous BP to treat metastatic bone lesions or multiple myeloma. However, more recent studies have indicated that BRONJ also frequently occurs in patients receiving low doses of BP for the treatment of osteoporosis. In addition, patients treated with denosumab, a human monoclonal antibody against receptor activator of nuclear factor-kappa B ligand (RANKL) whose antiresorptive effects differ from those of BP, may develop osteonecrosis of the jaw. Since both BP and denosumab are associated with osteonecrosis of the jaw (ONJ), antiresorptive agent-related ONJ (ARONJ) has been suggested as a comprehensive term. Although the pathophysiology of BRONJ remains unclear and the number of affected patients is increasing in Japan, significant improvements have been made with respect to risk reduction strategies and treatment. Despite the publication of the first position paper on BRONJ in Japan in 2010, an increase of the number of patients of BRONJ is hypothesized to result from an increase in the long-term use of BP. Previous findings have suggested that inadequate preventive measures including restriction of tooth extraction may be responsible for increases in BRONJ incidence.

Osteonecrosis of the jaws caused by bisphosphonate treatment and oxidative stress in mice

Aging is a significant risk factor for the development of bisphosphonate-related osteonecrosis of the jaws (BRONJ). Accumulating evidence suggests that bone aging is associated with oxidative stress (OS), and OS is associated with osteonecrosis. To elucidate the mechanisms of the onset of BRONJ, the present study focused on OS and the effects of treatment with the pro-oxidant DL-buthionine-(S,R)-sulfoximine (BSO), an oxidative stressor, on healing of a surgically induced penetrating injury of the palate. Six-week-old C57BL/6J mice were randomly divided into four groups (n=5 each) and treated with or without zoledronic acid (ZOL) and with or without BSO (experimental groups: ZOL, BSO, and ZOL+BSO; control group: saline solution). A penetrating injury of the midline palate was surgically created using a root elevator. ZOL (250 µg/kg/day) was injected intraperitoneally every day from 7 days prior to the surgical treatment to 4 days following the surgical treatment. BSO (500 µg/kg/day) was administered 7 days prior to the surgical treatment as a single intraperitoneal injection. The maxillae were harvested at 5 days following the surgical treatment for histological and histochemical studies. The presence of empty osteocyte lacunae in the palatal bone was increased by ZOL and BSO treatment. The highest number of empty osteocyte lacunae was observed in the ZOL+BSO group. The number of tartrate-resistant acid phosphatase-positive cells was decreased by ZOL treatment and increased by BSO treatment. The number of canaliculi per osteocyte lacuna was significantly decreased by BSO treatment. The mineral apposition rate was significantly lower in the treatment groups than the control group. Bisphosphonates and OS suppressed bone turnover. The present study has demonstrated that BSO treatment affects osteocytes, and OS in osteocytes exacerbates impairment of the osteocytic canalicular networks. As a result, bisphosphonates and OS may induce osteonecrosis following invasive dentoalveolar surgery. OS has been identified as an additional risk factor for the development of BRONJ.

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.

Microbial diversity in infections of patients with medication-related osteonecrosis of the jaw

OBJECTIVES

A central role of infections in the treatment of MRONJ patients is widely accepted. An investigation of the MRONJ lesions' biofilms as potential pathogens seems logical.

MATERIALS AND METHODS

We investigated the clinical data of our MRONJ patients who received surgery in advanced stage of the disease. Special attention was granted to the local colonizers harvested from osseous MRONJ specimens and submucosal putrid infections.

RESULTS

Eleven out of 71 patients presented a spontaneous onset of the disease and for 60 out of 71 patients a trigger was detected. Breast cancer (29.6%) and prostate cancer (22.5%) were the most frequent underlying disease for prescription of an antiresorptive therapy, mostly zoledronate. Submucosal soft tissue biofilms significantly differed from biofilms harvested from the MRONJ lesions bottom, yet the most frequent bacteria were equally present in both groups: Streptococcus species (spp.), Prevotella spp., Actinomyces spp., Veillonella spp., and Parvimonas micra. The cephalosporins, cefuroxime and cefotaxime, and ß-lactam antibiotics with ß-lactamase inhibitor revealed the greatest susceptibility for the detected bacteria.

CONCLUSION

The bacteria from the submucosal areas and the bottom of the infected bone presented comparable susceptibility to the common antibiotics regimes. Streptococcus spp., Prevotella spp., and Veillonella spp. present a high abundance in MRONJ lesions beside Actinomyces spp. The MRONJ lesions bottom is in many cases not infected by Actinomyces spp.

CLINICAL RELEVANCE

The removal of the necrotic bone reduces the variety of bacteria found in MRONJ lesions, in particular at the bottom of the lesion.

Drug holiday patterns and bisphosphonate-related osteonecrosis of the jaw

OBJECTIVES

There is limited evidence regarding the appropriate length of a bisphosphonate (BP) holiday to reduce the risk of osteonecrosis of the jaw (ONJ). In this cross-sectional study, we investigated the population-based patterns of the gaps between BP discontinuation and ONJ diagnosis.

SUBJECTS AND METHODS

We used the claims database of the National Health Insurance Service in Korea. Among BP users between 2006 and 2015, incident ONJ cases during 2010-2015 with no history of ONJ in the last 4 years were identified. We assessed the time gap from the last BP administration to ONJ diagnosis.

RESULTS

Among 1,569 incident ONJ cases, 836 (53.3%) occurred after BP discontinuation. The cumulative proportions of ONJ occurrence within 1 month, 3 months, 1 year, 2 years, and 3 years after discontinuation were 58.9%, 70.8%, 87.0%, 93.2%, and 96.1%, respectively. The length of drug holidays showed no significant difference between patients with or without comorbid cancer and diabetes mellitus (p-value, 0.12 and 0.52, respectively). However, the use of injectable BP formulations significantly affected ONJ incidence (p < 0.01).

CONCLUSIONS

Most ONJ cases occurred within 3 years from BP suspension, with a higher prevalence among BP injection users with 1 year or lesser BP holiday.

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.

Short-Term Teriparatide and Recombinant Human Bone Morphogenetic Protein-2 for Regenerative Approach to Medication-Related Osteonecrosis of the Jaw: A Preliminary Study

Our objective was to examine whether adjunct teriparatide administration and local application of recombinant human bone morphogenetic protein-2 (rhBMP-2) is beneficial for the regeneration of jaw bone in patients with medication-related osteonecrosis of the jaw (MRONJ). This study enrolled 17 patients diagnosed with MRONJ. All patients received sequestrectomy under general or local anesthesia with suspension of bisphosphonate. The bone regeneration ratio was compared on cone beam computed tomography (CBCT) scans, acquired immediately post-operation and after 6 months. The patients were divided into groups, based on their treatment regimens: teriparatide combined with rhBMP-2 (parathyroid hormone [PTH]+BMP), rhBMP-2 (BMP), and the control. Biochemical markers were also evaluated at the baseline (T0), 1 month (T1), and 3 months (T2) after surgery. Significant increase was observed in the values of the biochemical markers, serum osteocalcin, and serum C-terminal telopeptide cross-link of type I collagen, within 3 months of surgery in the PTH+BMP group, whereas the mean value in the BMP group did not show a significant change. In all groups, the MRONJ lesions were healed and new bone formation was detected in the CBCT images. The regeneration ratio was significantly greater in the group PTH+BMP than in the BMP and control groups. Significantly greater amount of bone formation was observed in the group PTH+BMP than in the BMP and control groups. Local application of rhBMP-2 alone also had a beneficial effect on bone regeneration but was not more significant than control. Based on these findings, administration of short-term teriparatide with rhBMP-2 in MRONJ patients may maximize the regeneration of bone after surgery. © 2017 American Society for Bone and Mineral Research.

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.

A Strategy against the Osteonecrosis of the Jaw Associated with Nitrogen-Containing Bisphosphonates (N-BPs): Attempts to Replace N-BPs with the Non-N-BP Etidronate

Bisphosphonate (BP)-related osteonecrosis of the jaw (BRONJ) can occur when enhanced bone-resorptive diseases are treated with nitrogen-containing BPs (N-BPs). Having previously found, in mice, that the non-N-BP etidronate can (i) reduce the inflammatory/necrotic effects of N-BPs by inhibiting their intracellular entry and (ii) antagonize the binding of N-BPs to bone hydroxyapatite, we hypothesized that etidronate-replacement therapy (Eti-RT) might be useful for patients with, or at risk of, BRONJ. In the present study we examined this hypothesis. In each of 25 patients receiving N-BP treatment, the N-BP was discontinued when BRONJ was suspected and/or diagnosed. After consultation with the physician-in-charge and with the patient's informed consent, Eti-RT was instituted in one group according to its standard oral prescription. We retrospectively compared this Eti-RT group (11 patients) with a non-Eti-RT group (14 patients). The Eti-RT group (6 oral N-BP patients and 5 intravenous N-BP patients) and the non-Eti-RT group (5 oral N-BP patients and 9 intravenous N-BP patients) were all stage 2-3 BRONJ. Both in oral and intravenous N-BP patients (particularly in the former patients), Eti-RT promoted or tended to promote the separation and removal of sequestra and thereby promoted the recovery of soft-tissues, allowing them to cover the exposed jawbone. These results suggest that Eti-RT may be an effective choice for BRONJ caused by either oral or intravenous N-BPs and for BRONJ prevention, while retaining a level of anti-bone-resorption. Eti-RT may also be effective at preventing BRONJ in N-BP-treated patients at risk of BRONJ. However, prospective trials are still required.

Inflammatory Effects of Nitrogen-Containing Bisphosphonates (N-BPs): Modulation by Non-N-BPs

Bisphosphonates (BPs) are used against diseases with enhanced bone resorption. Those classed as nitrogen-containing BPs (N-BPs) exhibit much stronger anti-bone-resorptive effects than non-nitrogen-containing BPs (non-N-BPs). However, N-BPs carry the risk of inflammatory/necrotic side effects. Depending on their side-chains, BPs are divided structurally into cyclic and non-cyclic types. We previously found in mice that etidronate and clodronate (both non-cyclic non-N-BPs) could reduce the inflammatory effects of all three N-BPs tested (cyclic and non-cyclic types), possibly by inhibiting their entry into soft-tissue cells via SLC20 and/or SLC34 phosphate transporters. Tiludronate is the only available cyclic non-N-BP, but its effects on N-BPs' side effects have not been examined. Here, we compared the effects of etidronate, clodronate, and tiludronate on the inflammatory effects of six N-BPs used in Japan [three cyclic (risedronate, zoledronate, minodronate) and three non-cyclic (pamidronate, alendronate, ibandronate)]. Inflammatory effects were evaluated in mice by measuring the hind-paw-pad swelling induced by subcutaneous injection of an N-BP (either alone or mixed with a non-N-BP) into the hind-paw-pad. All of six N-BPs tested induced inflammation. Etidronate, clodronate, and the SLC20/34 inhibitor phosphonoformate inhibited this inflammation. Tiludronate inhibited the inflammatory effects of all N-BPs except ibandronate and minodronate, which have higher molecular weights than the other N-BPs. The mRNAs of SLC20a1, SLC20a2, and SLC34a2 (but not of SLC34a1 and SLC34a3) were detected in the soft-tissues of hind-paw-pads. These results suggest that etidronate, clodronate, and phosphonoformate may act non-selectively on phosphate transporter members, while tiludronate may not act on those transporting N-BPs of higher molecular weights.

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.

Medication-related osteonecrosis of the jaws caused lethal sepsis in an edentulous patient with multiple systemic factors

Medication‐related osteonecrosis of the jaw (MRONJ) is developed even in the patients who are edentulous and treated with short‐term bisphosphonate therapy and oral administration. It sometimes causes lethal sepsis in patients who have multiple health problems such as diabetes, cirrhosis, steroid use for interstitial pneumonia, sepsis, and spinal disk herniation.

Bilateral Maxillary Reconstruction Using Fibular Flap in Bisphosphonate-related Osteonecrosis

Recent reports have shown successful transfer of vascularized fibular flap in bisphosphonate-induced mandibular osteonecrosis. We present a case of a 50-year-old patient who presented with bisphosphonate-related osteonecrosis of bilateral maxilla, which is reconstructed using a fibular flap.

Bisphosphonate related osteonecrosis of the jaws (BRONJ) in osteoporotic males

Background

The purpose of this study was to describe the clinical characteristics of bisphosphonate related osteonecrosis of the jaws (BRONJ) in osteoporotic males.

Methods

The medical records of BRONJ patients from 2007 to 2014 were reviewed. The data from only the male patients was extracted, and demographic data was collected and biochemical markers were measured.

Results

11 Patients out of 210 (5 %) being males. Among the 11 patients, the indication of bisphosphonate (BP) was osteoporosis in 9 patients, and cancer in two. In one of the osteoporosis patients, osteoporosis was thought to be secondary to hypogonadism after testicular tumor resection. Serum c-terminal telopetide crosslink of type I collagen (s-CTX) values ranged from 60 to 165 pg/mL (mean: 84.6 ± 36.8, median: 70). Serum osteocalcin (s-OC) ranged from 0 to 5.06 ng/mL (mean: 1.83 ± 1.66, median: 1.5) and vitamin D ranged from 0 to 11.9 (mean: 5.02 ± 4.92, median: 3.5).

Conclusion

BRONJ can be overlooked in male patients with osteoporosis. Although the incidence of BRONJ in males may be low, dentists should also check if their male patients are on osteoporosis treatment since osteoporosis in males can be manifested as a secondary disease to hypogonadism.

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.

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.

Establishment of an Animal Model of Bisphosphonate-Related Osteonecrosis of the Jaws in Spontaneously Diabetic Torii Rats

Background

We evaluated the side effects of bisphosphonate (BP) on tooth extraction socket healing in spontaneously diabetic Torii (SDT) rats, an established model of non-obese type 2 diabetes mellitus, to develop an animal model of BP-related osteonecrosis of the jaws (BRONJ).

Materials and Methods

Male Sprague-Dawley (SD) rats and SDT rats were randomly assigned to the zoledronic acid (ZOL)-treated groups (SD/ZOL or SDT/ZOL) or to the control groups (SD/control or SDT/control). Rats in the SD/ZOL or SDT/ZOL groups received an intravenous bolus injection of ZOL (35 μg/kg) every 2 weeks. Each group consisted of 6 rats each. Twenty-one weeks after ZOL treatment began, the left maxillary molars were extracted. The rats were euthanized at 2, 4, or 8 weeks after tooth extraction, and the total maxillae were harvested for histological and histochemical studies.

Results

In the oral cavity, bone exposure persisted at the tooth extraction site in all rats of the SDT/ZOL group until 8 weeks after tooth extraction. In contrast, there was no bone exposure in SD/control or SDT/control groups, and only 1 of 6 rats in the SD/ZOL group showed bone exposure. Histologically, necrotic bone areas with empty lacunae, microbial colonies, and less invasion by inflammatory cells were observed. The number of tartrate-resistant acid phosphatase-positive osteoclasts was lower in the SDT/ZOL group than in the SD/control group. The mineral apposition rate was significantly lower in the SDT/ZOL group compared with the SD/control group.

Conclusions

This study demonstrated the development of BRONJ-like lesions in rats and suggested that low bone turnover with less inflammatory cell infiltration plays an important role in the development of BRONJ.

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.