Macrophage Polarization during MRONJ Development in Mice

Macrophages are important regulators of bone remodeling, and M1 polarization is observed in the setting of medication-related osteonecrosis of the jaws (MRONJ). Here, we characterize the phenotype of macrophages during early stages of MRONJ development in zoledronate (ZA)-treated mice with periodontal disease and explore the role of rosiglitazone, a drug that has been reported to lower the M1/M2 macrophage ratio, in MRONJ burden. Mice received ZA, and experimental periodontal disease (EPD) was induced around their second left maxillary molar. The mice were euthanized 1, 2, or 4 wk later. Micro-computed tomography and histologic and immunohistochemical analyses were carried out. In a separate experiment, mice were treated with ZA in the absence or presence of rosiglitazone, EPD was induced for 5 wk, and the MRONJ burden was assessed. An M1 predilection was noted in ZA versus vehicle (Veh) mice at 1, 2, or 4 wk after ligature placement. M1 cells were found to be positive for MMP-13, and their presence coincided with disruption of the surrounding collagen network in ZA mice. Rosiglitazone caused a reversal in the M1/M2 polarization in Veh and ZA mice. Rosiglitazone did not cause significant radiographic changes 5 wk after EPD in Veh or ZA animals. Importantly, percentage osteonecrosis and bone exposure were decreased in the rosiglitazone-treated versus nontreated ZA sites 5 wk after EPD. Our data point to an important role of M1 macrophage polarization with an overexpression of MMP-13 in the early phases of MRONJ development and provide insight into the use of interventional approaches promoting an M2 phenotype as a preventative means to alleviate MRONJ burden.

How we manage medication-related osteonecrosis of the jaw

Bone-modifying agents (BMAs) are integral to managing patients with advanced cancer. They improve quality of survival by reducing skeletal-related events, treating hypercalcaemia and chemotherapy-induced bone loss (Coleman in Clin Cancer Res 12: 6243s-6249s, 2006), (Coleman in Ann Oncol 31: 1650-1663, 2020). Two decades ago, medication-related osteonecrosis of the jaw (MRONJ) was first reported following BMA therapy (Marx in J Oral Maxillofac Surg 61: 1115-1117, 2003). The risk of MRONJ extends over a decade following BMA treatment with bisphosphonates, complicating dental care such as extractions. In addition, MRONJ has been reported following additional therapies such as antiangiogenic agents, cytotoxic agents, immunotherapy, and targeted agents. The use of BMAs in the curative and adjuvant cancer setting is increasing, consequently the implication of MRONJ is growing. Over the past 20 years, the literature has consolidated major risk factors for MRONJ, the pathophysiology and management strategies for MRONJ. Our review aims to document the development of MRONJ preventative and management strategies in cancer patients receiving a BMA. The authors advocate the incorporation of dental oncology strategies into contemporary cancer care, to optimise long-term quality of survival after cancer treatment.

Challenges in the Diagnosis and Treatment of Oral Amelanotic Malignant Melanoma: A Case Report

Oral malignant melanoma (OMM) is extremely rare and usually has a poor prognosis. Early diagnosis is very important and can improve survival but it is usually difficult due to a lack of symptomatology. We present the first case of a 39-year-old East European woman with oral amelanotic melanoma, who underwent surgery and adjuvant immunotherapy; however, after six months, she developed local recurrence. The patient continued immunotherapy with external radiotherapy targeting the oral tumor recurrence. During therapy, imagistic reevaluation brought evidence of bones, lungs, liver, endotracheal, and brain metastases. Histological differential diagnosis between amelanotic OMM and leiomyosarcoma was necessary to establish the right course of treatment. A series of complications further delayed chemotherapy administration, making the treatment in this case very challenging. The patient had a significant, although late response to immunotherapy, and maintained a good performance status during disease progression with a survival of 15 months until present.

Risk of healing impairment following tooth extraction in patients administered with antiresorptive and non-antiresorptive polypharmacy

INTRODUCTION

Lack of evidence existed related to the essential role by which anticancer medications alone or in combination with other polypharmacy would be accountable for wound healing impairment post-dental extraction. The following study was conducted to assess the influence of antiresorptive (AR) and non-antiresorptive (non-AR) drugs and other patient-related risk factors on wound healing status following tooth extraction.

MATERIAL AND METHODS

A total of 353 patients (age range: 40-90 years, average age: 67.4 years, clinical and radiological follow-up) were recruited. All the patients were divided into three groups, which included, patients used polypharmacy with non-AR drugs, polypharmacy with a combination of AR + non-AR drugs, and the control group. Based on time of healing, the outcome was defined as, normal healing, delayed healing, and Medication-related osteonecrosis of the jaw (MRONJ). The polypharmacy score was categorized depending on the sum of the number of administered medications.

RESULTS

The odds of delayed healing were significantly higher in 80+ years old patients (OR=6.98, 95 %CI:2.45-19.88, p = < 0.001) administered with AR+ non-AR drugs (OR=14.68, 95 %CI:4.67-46.14, p = < 0.001), having a major polypharmacy score (OR= 15.37, 95 %CI:4.83-48.91, p = < 0.001). On the contrary, patient administered with non-AR drugs (OR=11.52, 95 %CI: 4.45-29.83, p = < 0.001) with hyper polypharmacy (OR=58.86, 95 %CI:25.03-138.40, p = < 0.001) were significantly more likely to develop MRONJ. Smoking and extraction sites showed no significant impact on wound healing impairment.

DISCUSSION

Wound healing status in patients administered with both non-AR and AR+ non-AR polypharmacy was significantly impaired following tooth extraction. Other risk factors, such as increased age and high polypharmacy scoring, also significantly contributed towards the occurrence of delayed healing and MRONJ.

Highlights on the Effects of Non-Coding RNAs in the Osteonecrosis of the Jaw

Osteonecrosis of the jaw is the progressive loss and destruction of bone affecting the maxilla or mandible in patients treated with antiresorptive and antiangiogenic agents without receiving prior radiation therapy. The pathogenesis involves the inflammatory pathway of receptor activator of nuclear factor NF-kB ligand and the macrophage colony-stimulating factor, essential for osteoclast precursors survival and proliferation and acting through its receptor c-Fms. Evidence has shown the role of non-coding RNAs in the pathogenesis of osteonecrosis of the jaw and this finding might be useful in diagnosis since these small RNAs could be considered as biomarkers of apoptotic activity in bone. Interestingly, it has been proved that miR-29 and miR-31-5p, acting on specific targets such as CALCR and RhoA, promote programmed-cell death and consequently the necrosis of bone tissue. Specific long non-coding RNAs, instead, have been detected both at reduced levels in patients with multiple myeloma and osteonecrosis, and associated with suppression of osteoblast differentiation, with consequences in the progression of mandible lesions. Among non-coding genic material, circular RNAs have the capability to modify the expression of specific mRNAs responsible for the inhibition of bisphosphonates activity on osteoclastogenesis.

Osteonecrosis of the jaw under palbociclib: A case series description

INTRODUCTION

Cases of osteonecrosis of the jaw have been reported by dental surgeons to the pharmacovigilance center in Rennes, France, occurring among patients treated with palbociclib, a cyclin-dependent kinase 4/6 inhibitor. Although this event was not expected with the drug, a safety signal was raised. Describing a local case series, the aim of our study was to identify specific patterns that might suggest a triggering role for these drugs, and to discuss pathophysiological hypotheses.

MATERIALS AND METHODS

A retrospective case series of patients exposed to cyclin-dependent kinase 4/6 inhibitors between 2016 and 2020 with a diagnosis of osteonecrosis of the jaw at the Rennes Dental Care Center was analyzed. The descriptive analysis was conducted on patient demographics, breast cancer characteristics, osteonecrosis of the jaw, biological data, and exposure to cyclin-dependent kinase 4/6 inhibitors.

RESULTS

We identified eight cases, most of them at stages 0-1 (62.5%). Four patients were still exposed to palbociclib at the time of diagnosis and four had discontinued the treatment before the diagnosis. Chronological imputability could not be excluded given the drug's half-life and the variable intervals of dental monitoring from one patient to another. All patients had at least one dental osteonecrosis risk factor (including dental extraction, dentures, and denosumab exposure at the time of diagnosis). Neutropenia and mucositis were not systematically reported at the time of diagnosis. The anatomopathological characteristics were nonspecific.

CONCLUSION

We did not identify a specific pattern that could suggest a triggering role of palbociclib in the development of ONJ.

Bisphosphonates and osteonecrosis of the jaws: Clinical and forensic aspects

OBJECTIVE

This manuscript aims to provide a comprehensive review of the current knowledge in the pathophysiology, diagnosis, prevention, and other relevant clinical and forensic aspects of a potentially severe complication known as medication-related osteonecrosis of the jaw (MRONJ) while synthesizing state-of-the-art information on bisphosphonates and introducing a possible differential diagnosis.

DESIGN

An extensive search was conducted in PubMed (U.S. National Library of Medicine) without a time or language constraint, focusing on the epidemiology, pathophysiology, risk factors, site specificity, signs and symptoms, differential diagnosis, prevention, and forensic aspects of MRONJ. All types of original articles, reviews, case reports, short communications, opinion articles, guidelines, and letters to editors were considered to produce a complete review on this subject.

RESULTS

MRONJ prevention relies on a multidisciplinary approach and is critical since truly effective treatments are lacking. This therapeutic challenge is partly due to uncertainty regarding this condition's pathophysiology. Differential diagnosis of osteonecrosis of the jaws associated with krokodil abuse, one of the most dangerous and homemade psychoactive illicit substances, should be considered.

CONCLUSIONS

Further research into the etiology and site specificity of MRONJ is encouraged, aiming to develop novel treatment prospects. Indeed, comprehending this would allow for increased efficacy and therapeutic options while emphasizing the importance of prevention. In addition, we advocate for greater consensus among the various societies regarding MRONJ's treatment and management.

Pathophysiology of Medication-Related Osteonecrosis of the Jaw-A Minireview

Medication-related osteonecrosis of the jaw (MRONJ) is a rare but serious adverse effect of antiresorptive medications administered for control of osseous malignancy, osteoporosis, or other bone metabolic diseases. Despite being reported in the literature two decades ago, MRONJ etiology, pathophysiology, and progression remain largely unknown, and current nonoperative or operative treatment strategies are mostly empirical. Several hypotheses that attempt to explain the mechanisms of MRONJ pathogenesis have been proposed. However, none of these hypotheses alone is able to capture the complex mechanistic underpinnings of the disease. In this minireview, we aim to highlight key findings from clinical and translational studies and propose a unifying model for the pathogenesis and progression of MRONJ. We also identify aspects of the disease process that require further investigation and suggest areas for future research efforts toward calibrating methodologic approaches and validating experimental findings. © 2023 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

Anti-resorptive therapy in the osteometabolic patient affected by periodontitis. A joint position paper of the Italian Society of Orthopaedics and Traumatology (SIOT) and the Italian Society of Periodontology and Implantology (SIdP)

This joint report from the Italian Society of Orthopaedics and Traumatology (SIOT) and the Italian Society of Periodontology and Implantology (SIdP) aims for a consensus around the scientific rationale and clinical strategy for the management of osteoporotic patients affected by periodontitis who are undergoing anti-resorptive (AR) therapy to manage the risk of the occurrence of a medication-related osteonecrosis of the jaws (MRONJ). Osteoporosis and periodontitis are chronic diseases with a high prevalence in aging patients, and they share some of the same pathogenetic mechanisms based upon inflammation. Available evidence shows the relationship among osteoporosis, AR agents, periodontitis and implant therapy in relation to the incidence of MRONJ. Uncontrolled periodontitis may lead to tooth loss and to the need to replace teeth with dental implants. Tooth extraction and surgical dental procedures are recognized as the main risk factors for developing MRONJ in individuals taking AR therapy for osteometabolic conditions. Although the incidence of MRONJ in osteometabolic patients taking AR therapy may be as low as 0.9%, the increasing prevalence of osteoporosis and the high prevalence of periodontitis suggest that this potential complication should not be overlooked. Good clinical practice (GCP) guidelines are proposed that aim at a more integrated approach (prescriber, dentist, periodontist and dental hygienist) in the management of periodontitis patients undergoing AR therapy for osteometabolic disorders to reduce the risk of MRONJ. Dental professional and prescribers should educate patients regarding the potential risk associated with the long-term use of AR therapy and oral health behavior.

Intermittent parathyroid hormone enhances the healing of medication-related osteonecrosis of the jaw lesions in rice rats

Medication-related osteonecrosis of the jaw (MRONJ) is a potentially severe adverse event in patients treated with antiresorptives. Management of MRONJ is challenging, and no non-antibiotic, established medical treatment exists. Intermittent parathyroid hormone (iPTH) has been used off-label to treat MRONJ with favorable results. However, its medical efficacy has rarely been substantiated in clinical or preclinical experiments. Using a validated rice rat, infection-based model of MRONJ, we evaluated the effects of iPTH on established MRONJ. We hypothesize that iPTH contributes to MRONJ resolution by enhancing alveolar bone turnover and healing oral soft tissues. Eighty-four rice rats began a standard rodent chow diet at age 4 weeks to induce localized periodontitis. Rats were simultaneously randomized to receive saline (vehicle, VEH) or zoledronic acid (ZOL, 80 μg/kg IV) every 4 weeks. Oral exams were conducted bi-weekly to assign a gross quadrant grade (GQG, 0-4) to evaluate any lesion at the lingual aspect of the interdental space between maxillary molar (M2) and M3. 14 of 20 VEH-treated rice rats (70%) developed maxillary localized periodontitis with GQG 2-3 after 30 ± 10 weeks of saline. Additionally, 40 of 64 ZOL-treated rice rats with periodontitis developed MRONJ-like lesions after 30 ± 10 weeks of ZOL treatment. Rice rats with localized periodontitis or MRONJ-like lesions were treated with saline or iPTH (40 μg/kg) subcutaneously (SC) 3 times/week For 6 weeks until euthanasia. We found that iPTH -treated ZOL rats had a lower prevalence of MRONJ (p < 0.001), with lower severity extent of oral lesions (p = 0.003) and percentage of empty osteocyte lacunae (p < 0.001). ZOL rats treated with iPTH displayed a higher osteoblast surface (p < 0.001), more osteoblasts (p < 0.001), higher osteoclast surface (p < 0.001) and more osteoclasts (p = 0.002) at alveolar bone surfaces than ZOL/VEH rats. Greater gingival epithelial thickness and epithelial cell proliferation rate was found in the oral mucosa and gingiva of ZOL/PTH rats than in ZOL/VEH rats (p < 0.001). Our data suggest that iPTH is an efficacious non-operative medicinal therapy that accelerates oral healing and enhances the resolution of MRONJ lesions in ZOL-treated rice rats.

Customized Titanium Mesh for Guided Bone Regeneration in the Posterior Mandible in a Patient Previously Treated with Bisphosphonates

We describe the restorative treatment of an 86-year-old female patient who was referred to our specialist prosthodontics clinic. Due to secondary osteoporosis, she underwent oral antiresorptive therapy with ibandronic acid for 10 years. Although she was classified as a patient at increased risk of drug-induced osteonecrosis of the jaw, she eventually signed a consent form for fixed implant-supported prosthetic rehabilitation in her 4th sextant. However, after tooth extraction, the bone ridge was too small at the intended implant positions. Therefore, guided bone regeneration was performed with a computer-aided design/computer-aided manufacturing three-dimensional printed titanium mesh. Finally, a continuous augmented hard tissue ridge above 7 mm was found, and three implants were inserted. Eventually, after four months of submerged healing, the implants were loaded with single crowns. Now, the patient is seen regularly for supportive peri-implant therapy.

Risk factors for medication-related osteonecrosis of the jaw and salivary IL-6 IN cancer patients

Introduction

Medication-related osteonecrosis of the jaws is a severe complication of the use of antiresorptive and antiangiogenic therapy, with limited treatment options and great impact on patient’s quality pf life.

Objective

The aim of this study was to assess the risk factors associated with medication-related osteonecrosis of the jaws in oncologic patients undergoing bisphosphonate treatment. In addition, salivary levels of interleukin-6, IL-6, were measured to investigate their association with severity and risk of medication-related osteonecrosis of the jaws.

Methods

Case-control study with 74 patients with bone metastases from solid tumors and multiple myeloma was included. Patients were divided into three groups: 1) those undergoing bisphosphonate treatment with medication-related osteonecrosis of the jaws; 2) those undergoing bisphosphonate without medication-related osteonecrosis of the jaws; and 3) those with bisphosphonate pretreatment. The demographic and medical data of the patients were collected to assess risk. The clinical evaluation was performed to diagnose medication-related osteonecrosis of the jaws and unstimulated saliva was collected for quantification of IL-6.

Results

As result, it was observed that patients diagnosed with medication-related osteonecrosis of the jaws were submitted to higher number of bisphosphonate doses (p = 0.001) and monthly infusion protocol (p = 0.044; OR = 7.75). Patients who did not have routine followup with specialized dentists during therapy with bisphosphonate and smoking were associated with medication-related osteonecrosis of the jaws (p = 0.019; OR = 8.25 and p = 0.031; OR = 9.37 respectively). Group 1 had a higher frequency of treatment with chemotherapy and corticosteroids concomitant with bisphosphonate, and surgical dental procedures (p = 0.129). Salivary IL-6 levels showed no statistically significant difference between the groups (p = 0.571) or association with medication-related osteonecrosis of the jaws severity (p = 0.923).

Conclusion

A higher number of bisphosphonate cycles, monthly infusion protocol, no dental follow-up for oral health maintenance and smoking were associated with medication-related osteonecrosis of the jaws. Specialized dental follow up during bisphosphonate treatment has been shown to be an important factor in preventing this complication.

Interventions for managing medication-related osteonecrosis of the jaw

BACKGROUND

Medication-related osteonecrosis of the jaw (MRONJ) is a severe adverse reaction experienced by some individuals to certain medicines commonly used in the treatment of cancer and osteoporosis (e.g. bisphosphonates, denosumab, and antiangiogenic agents), and involves the progressive destruction of bone in the mandible or maxilla. Depending on the drug, its dosage, and the duration of exposure, this adverse drug reaction may occur rarely (e.g. following the oral administration of bisphosphonate or denosumab treatments for osteoporosis, or antiangiogenic agent-targeted cancer treatment), or commonly (e.g. following intravenous bisphosphonate for cancer treatment). MRONJ is associated with significant morbidity, adversely affects quality of life (QoL), and is challenging to treat. This is an update of our review first published in 2017.

OBJECTIVES

To assess the effects of interventions versus no treatment, placebo, or an active control for the prophylaxis of MRONJ in people exposed to antiresorptive or antiangiogenic drugs. To assess the effects of non-surgical or surgical interventions (either singly or in combination) versus no treatment, placebo, or an active control for the treatment of people with manifest MRONJ.

SEARCH METHODS

Cochrane Oral Health's Information Specialist searched four bibliographic databases up to 16 June 2021 and used additional search methods to identify published, unpublished, and ongoing studies.  SELECTION CRITERIA: We included randomised controlled trials (RCTs) comparing one modality of intervention with another for the prevention or treatment of MRONJ. For 'prophylaxis of MRONJ', the primary outcome of interest was the incidence of MRONJ; secondary outcomes were QoL, time-to-event, and rate of complications and side effects of the intervention. For 'treatment of established MRONJ', the primary outcome of interest was healing of MRONJ; secondary outcomes were QoL, recurrence, and rate of complications and side effects of the intervention.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened the search results, extracted the data, and assessed the risk of bias in the included studies. For dichotomous outcomes, we reported the risk ratio (RR) (or rate ratio) and 95% confidence intervals (CIs).

MAIN RESULTS

We included 13 RCTs (1668 participants) in this updated review, of which eight were new additions. The studies were clinically diverse and examined very different interventions, so meta-analyses could not be performed. We have low or very low certainty about available evidence on interventions for the prophylaxis or treatment of MRONJ. Prophylaxis of MRONJ Five RCTs examined different interventions to prevent the occurrence of MRONJ. One RCT compared standard care with regular dental examinations at three-month intervals and preventive treatments (including antibiotics before dental extractions and the use of techniques for wound closure that avoid exposure and contamination of bone) in men with metastatic prostate cancer treated with zoledronic acid. The intervention seemed to lower the risk of MRONJ (RR 0.10, 95% CI 0.02 to 0.39, 253 participants). Secondary outcomes were not evaluated. Dentoalveolar surgery is considered a common predisposing event for developing MRONJ and five RCTs tested various preventive measures to reduce the risk of postoperative MRONJ. The studies evaluated plasma rich in growth factors inserted into the postextraction alveolus in addition to standardised medical and surgical care versus standardised medical and surgical care alone (RR 0.08, 95% CI 0.00 to 1.51, 176 participants); delicate surgery and closure by primary intention versus non-traumatic tooth avulsion and closure by secondary intention (no case of postoperative MRONJ in either group); primary closure of the extraction socket with a mucoperiosteal flap versus application of platelet-rich fibrin without primary wound closure (no case of postoperative MRONJ in either group); and subperiosteal wound closure versus epiperiosteal wound closure (RR 0.09, 95% CI 0.00 to 1.56, 132 participants).  Treatment of MRONJ Eight RCTs examined different interventions for the treatment of established MRONJ; that is, the effect on MRONJ cure rates.  One RCT analysed hyperbaric oxygen (HBO) treatment used in addition to standard care (antiseptic rinses, antibiotics, and surgery) compared with standard care alone (at last follow-up: RR 1.56, 95% CI 0.77 to 3.18, 46 participants).  Healing rates from MRONJ were not significantly different between autofluorescence-guided bone surgery and conventional bone surgery (RR 1.08, 95% CI 0.85 to 1.37, 30 participants). Another RCT that compared autofluorescence- with tetracycline fluorescence-guided sequestrectomy for the surgical treatment of MRONJ found no significant difference (at one-year follow-up: RR 1.05, 95% CI 0.86 to 1.30, 34 participants).  Three RCTs investigated the effect of growth factors and autologous platelet concentrates on healing rates of MRONJ: platelet-rich fibrin after bone surgery versus surgery alone (RR 1.05, 95% CI 0.90 to 1.22, 47 participants), bone morphogenetic protein-2 together with platelet-rich fibrin versus platelet-rich fibrin alone (RR 1.10, 95% CI 0.94 to 1.29, 55 participants), and concentrated growth factor and primary wound closure versus primary wound closure only (RR 1.38, 95% CI 0.81 to 2.34, 28 participants).   Two RCTs focused on pharmacological treatment with teriparatide: teriparatide 20 μg daily versus placebo in addition to standard care (RR 0.96, 95% CI 0.31 to 2.95, 33 participants) and teriparatide 56.5 μg weekly versus teriparatide 20 μg daily in addition to standard care (RR 1.60, 95% CI 0.25 to 1.44, 12 participants).

AUTHORS CONCLUSIONS

Prophylaxis of medication-related osteonecrosis of the jaw One open-label RCT provided some evidence that dental examinations at three-month intervals and preventive treatments may be more effective than standard care for reducing the incidence of medication-related osteonecrosis of the jaw (MRONJ) in individuals taking intravenous bisphosphonates for advanced cancer. We assessed the certainty of the evidence to be very low. There is insufficient evidence to either claim or refute a benefit of the interventions tested for prophylaxis of MRONJ in patients with antiresorptive therapy undergoing dentoalveolar surgery. Although some interventions suggested a potential large effect, the studies were underpowered to show statistical significance, and replication of the results in larger studies is pending. Treatment of medication-related osteonecrosis of the jaw The available evidence is insufficient to either claim or refute a benefit, in addition to standard care, of any of the interventions studied for the treatment of MRONJ.

A Retrospective Data Analysis for the Risk Evaluation of the Development of Drug-Associated Jaw Necrosis through Dentoalveolar Interventions

This study aimed to analyse the development of medication-related osteonecrosis of the jaw (MRONJ) in patients who underwent surgical intervention to identify potential risk factors between three different groups sorted by the type of oral surgery (single tooth extraction, multiple extraction, osteotomy). Data from patients with this medical history between 2010 and 2017 were retrospectively analysed. The following parameters were collected: sex, age, medical status, surgical intervention location of dentoalveolar intervention and form of medication. A total of 115 patients fulfilled the criteria and underwent 115 dental surgical interventions (female n = 90, male n = 25). In total, 73 (63.47%) of them had metastatic underlying diseases, and 42 (36.52%) had osteoporotic ones. MRONJ occurred in 10 patients (8.70%) (female n = 5, male n = 5). The occurrence of MRONJ was significantly correlated (p ≤ 0.05) with the mandible site and male sex. Tooth removal at the mandible site remains the main risk factor for the development of MRONJ. The risk profile of developing MRONJ after dentoalveolar interventions could be expected as follows: tooth osteotomy > multiple extractions > single tooth extraction.

Indigenous microbiota protects development of medication-related osteonecrosis induced by periapical disease in mice

Bacterial infection is a common finding in patients, who develop medication-related osteonecrosis of the jaw (MRONJ) by the long-term and/or high-dose use of anti-resorptive agents such as bisphosphonate (BPs). However, pathological role of bacteria in MRONJ development at the early stage remains controversial. Here, we demonstrated that commensal microbiota protects against MRONJ development in the pulp-exposed periapical periodontitis mouse model. C57/BL6 female mice were treated with intragastric broad-spectrum antibiotics for 1 week. Zoledronic acid (ZOL) through intravenous injection and antibiotics in drinking water were administered for throughout the experiment. Pulp was exposed on the left maxillary first molar, then the mice were left for 5 weeks after which bilateral maxillary first molar was extracted and mice were left for additional 3 weeks to heal. All mice were harvested, and cecum, maxilla, and femurs were collected. ONJ development was assessed using μCT and histologic analyses. When antibiotic was treated in mice, these mice had no weight changes, but developed significantly enlarged ceca compared to the control group (CTL mice). Periapical bone resorption prior to the tooth extraction was similarly prevented when treated with antibiotics, which was confirmed by decreased osteoclasts and inflammation. ZOL treatment with pulp exposure significantly increased bone necrosis as determined by empty lacunae and necrotic bone amount. Furthermore, antibiotics treatment could further exacerbate bone necrosis, with increased osteoclast number. Our findings suggest that the commensal microbiome may play protective role, rather than pathological role, in the early stages of MRONJ development.

Bone Targeting Agents in Patients with Prostate Cancer: General Toxicities and Osteonecrosis of the Jaw

Introduction: Bone metastases are the most frequent site of secondary localization of prostate cancer (PCa) and are present in about 90% of cases of advanced disease. Consequently, an adequate management of bone involvement is of pivotal importance in the therapeutic approach and skeletal-related events (SREs) need to be closely monitored and promptly assessed and treated. Bone targeting agents (BTAs), consisting in bisphosphonates and denosumab, are an essential part of the treatment of metastatic prostate cancer that accompanies systemic treatments throughout the most part of the history of the disease. Activity and safety of bone targeting agents: These treatments are correlated to better outcomes in terms of reduction of SREs and, in metastatic castration resistant setting, of increased overall survival (OS), but several important adverse events have to be managed and prevented. Of these, osteonecrosis of the jaw (ONJ) is extremely invalidating and should be managed with a special attention. Discussion: The role of BTAs in prostate cancer is pivotal throughout many stages of the disease, but several toxicities should be quickly recognized and treated. We aim at recollecting evidence on clinical benefit of BTAs, common and specific toxicities, and explore the pathophysiology and clinical aspects of osteonecrosis of the jaw. We present a review of the literature to report the role of the different types of bone targeting agents in the management of prostate cancer with bone metastases with a particular focus on common toxicities and ONJ to recollect current evidences on the activity of these compounds and the correct management of their adverse events.

Targeted histological evaluation shows high incidence of actinomyces infection in medication-related osteonecrosis of the jaws

Medication-Related Osteonecrosis of the Jaws (MRONJ) is a difficult-to-treat complication of the therapy of osteoporosis and some malignancies cured with bisphosphonates and antiresorptive drugs. The pathomechanism is unclear, but there is increasing observation that Actinomyces infection may play a role in its development and progression. The aim of our study was to demonstrate that histological examination using a validated triple staining procedure for Actinomyces bacteria strains can detect a high rate of Actinomyces infection in patient's samples with MRONJ. 112 previously hematoxylin-eosin (HE) stained samples submitted with the clinical diagnosis of MRONJ were re-evaluated histologically using an appropriate triple special staining validated for the identification of Actinomyces infection. During the first evaluation, when pathologists did not specifically look for Actinomyces, only 8.93% of the samples were reported as positive. In contrast, re-evaluation with triple staining provided a yield of 93.7% positive samples, therefore, we suggest the triple special staining to be standard in MRONJ histology evaluation. These results show that if the clinician suspects Actinomyces infection and brings this to the attention of the pathologist, it could significantly increase the number of correct diagnoses. It serves as an aid for clinicians in therapeutic success of MRONJ by selecting a long-term adequate antibiotic medication which is suitable for the elimination of actinomyces infection.

Transcriptional Regulation of Jaw Osteoblasts: Development to Pathology

Craniofacial and jaw bones have unique physiological specificities when compared to axial and appendicular bones. However, the molecular profile of the jaw osteoblast (OB) remains incomplete. The present study aimed to decipher the bone site-specific profiles of transcription factors (TFs) expressed in OBs in vivo. Using RNA sequencing analysis, we mapped the transcriptome of confirmed OBs from 2 different skeletal sites: mandible (Md) and tibia (Tb). The OB transcriptome contains 709 TF genes: 608 are similarly expressed in Md-OB and Tb-OB, referred to as "OB-core"; 54 TF genes are upregulated in Md-OB, referred to as "Md-set"; and 18 TF genes are upregulated in Tb-OB, referred to as "Tb-set." Notably, the expression of 29 additional TF genes depends on their RNA transcript variants. TF genes with no previously known role in OBs and bone were identified. Bioinformatics analysis combined with review of genetic disease databases and a comprehensive literature search showed a significant contribution of anatomical origin to the OB signatures. Md-set and Tb-set are enriched with site-specific TF genes associated with development and morphogenesis (neural crest vs. mesoderm), and this developmental imprint persists during growth and homeostasis. Jaw and tibia site-specific OB signatures are associated with craniofacial and appendicular skeletal disorders as well as neurocristopathies, dental disorders, and digit malformations. The present study demonstrates the feasibility of a new method to isolate pure OB populations and map their gene expression signature in the context of OB physiological environment, avoiding in vitro culture and its associated biases. Our results provide insights into the site-specific developmental pathways governing OBs and identify new major OB regulators of bone physiology. We also established the importance of the OB transcriptome as a prognostic tool for human rare bone diseases to explore the hidden pathophysiology of craniofacial malformations, among the most prevalent congenital defects in humans.

A Review Into the Effects of Pamidronic Acid and Zoledronic Acid on the Oral Mucosa in Medication-Related Osteonecrosis of the Jaw

Medication-related osteonecrosis of the jaw (MRONJ) is a growing problem without an effective treatment, presenting as necrotic bone sections exposed via lesions in the overlying soft tissue. There is currently a lack of clarity on how the factors involved in MRONJ development and progression contribute to disease prognosis and outcomes. Bisphosphonates (BPs), the most common cause of MRONJ, affect bone remodeling, angiogenesis, infection, inflammation and soft tissue toxicity, all of which contribute to MRONJ development. This article reviews the cellular mechanisms through which BPs contribute to MRONJ pathology, with a focus on the effects on cells of the oral mucosa. BPs have been shown to reduce cell viability, reduce proliferation, and increase apoptosis in oral keratinocytes and fibroblasts. BPs have also been demonstrated to reduce epithelial thickness and prevent epithelial formation in three-dimensional tissue engineered models of the oral mucosa. This combination of factors demonstrates how BPs lead to the reduced wound healing seen in MRONJ and begins to uncover the mechanisms through which these effects occur. The evidence presented here supports identification of targets which can be used to develop novel treatment strategies to promote soft tissue wound healing and restore mucosal coverage of exposed bone in MRONJ.

Expression of angiogenic markers in jawbones and femur in a rat model treated with zoledronic acid

Objectives

This study aimed to investigate the gene expression of angiogenic marker in surgically treated jawbones and femur on a rat model administrated with zoledronic acid.

Results

No soft tissue fenestration or bone exposure was found in femur. Delayed soft tissue healing was found in both ZA group (3 in mandible, 4 in maxilla) and control group (1 in mandible, 2 in maxilla), while exposed bone was found only in the ZA group (1 in maxilla, 2 in mandible). RT-PCR analysis demonstrated no significant difference in gene expression of angiogenetic markers between ZA-treated and control groups in femur and mandible. In the maxilla, the expression of VEGFA and VEGFR-2 in medium-term ZA group was significantly down-regulated compared with that in the control. The ZA treatment does not change significantly the expression of the angiogenic factors in femur and mandible, but significantly downregulates the expression in maxilla in this rat model. The angiogenesis inhibition may contribute to the development of MRONJ but does not play a key role.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13104-021-05900-5.

Biologic and pathologic aspects of osteocytes in the setting of medication-related osteonecrosis of the jaw (MRONJ)

Medication-related osteonecrosis of the jaw (MRONJ) is a potentially severe, debilitating condition affecting patients with cancer and patients with osteoporosis who have been treated with powerful antiresorptives (pARs) or angiogenesis inhibitors (AgIs). Oral risk factors associated with the development of MRONJ include tooth extraction and inflammatory dental disease (e.g., periodontitis, periapical infection). In bone tissues, osteocytes play a bidirectional role in which they not only act as the "receiver" of systemic signals from blood vessels, such as hormones and drugs, or local signals from the mineralized matrix as it is deformed, but they also play a critical role as "transmitter" of signals to the cells that execute bone modeling and remodeling (osteoclasts, osteoblasts and lining cells). When the survival capacity of osteocytes is overwhelmed, they can die. Osteocyte death has been associated with several pathological conditions. Whereas the causes and mechanisms of osteocyte death have been studied in conditions like osteonecrosis of the femoral head (ONFH), few studies of the causes and mechanisms of osteocyte death have been done in MRONJ. The three forms of cell death that affect most of the different cells in the body (apoptosis, autophagy, and necrosis) have been recognized in osteocytes. Notably, necroptosis, a form of regulated cell death with "a necrotic cell death phenotype," has also been identified as a form of cell death in osteocytes under certain pathologic conditions. Improving the understanding of osteocyte death in MRONJ may be critical for preventing disease and developing treatment approaches. In this review, we intend to provide insight into the biology of osteocytes, cell death, in general, and osteocyte death, in particular, and discuss hypothetical mechanisms involved in osteocyte death associated with MRONJ.

Engineered osteoclasts resorb necrotic alveolar bone in anti-RANKL antibody-treated mice

Medication-related osteonecrosis of the jaw (MRONJ) is a serious side effect of antiresorptive medications such as denosumab (humanized anti-RANKL antibody), yet its pathophysiology remains elusive. It has been posited that inhibition of osteoclastic bone resorption leads to the pathological sequelae of dead bone accumulation, impaired new bone formation, and poor wound healing in MRONJ, but this hypothesis has not been definitively tested. We previously engineered myeloid precursors with a conditional receptor activator of nuclear factor kappa-Β intracellular domain (iRANK cells), which differentiate into osteoclasts in response to a chemical inducer of dimerization (CID) independently of RANKL. In this study, we showed that CID-treated iRANK cells differentiated into osteoclasts and robustly resorbed mineralized surfaces even in the presence of anti-RANKL antibody in vitro. We then developed a tooth extraction-triggered MRONJ model in nude mice using anti-RANKL antibody to deplete osteoclasts. This model was used to determine whether reconstitution of engineered osteoclasts within sockets could prevent specific pathological features of MRONJ. Locally delivered iRANK cells successfully differentiated into multinucleated osteoclasts in response to CID treatment in vivo as measured by green fluorescent protein (GFP), tartrate-resistant acid phosphatase (TRAP), carbonic anhydrase II, matrix metallopeptidase 9 (MMP-9), and cathepsin K staining. Sockets treated with iRANK cells + CID had significantly more osteoclasts and less necrotic bone than those receiving iRANK cells alone. These data support the hypothesis that osteoclast deficiency leads to accumulation of necrotic bone in MRONJ.

Preclinical models of medication-related osteonecrosis of the jaw (MRONJ)

Medication-related osteonecrosis of the jaw (MRONJ) is a potentially severe adverse event affecting patients with cancer and patients with osteoporosis who have been treated with powerful antiresorptives (pARs) or angiogenesis inhibitors (AgIs). pARs, including nitrogen-containing bisphosphonates (N-BPs; e.g., zoledronic acid, alendronate) and anti-RANKL antibodies (e.g., denosumab), are used to manage bone metastases in patients with cancer or to prevent fragility fractures in patients with osteoporosis. Though significant advances have been made in understanding MRONJ, its pathophysiology is still not fully elucidated. Multiple species have been used in preclinical MRONJ research, including the rat, mouse, rice rat, rabbit, dog, sheep, and pig. Animal research has contributed immensely to advancing the MRONJ field, particularly, but not limited to, in developing models and investigating risk factors that were first observed in humans. MRONJ models have been developed using clinically relevant doses of systemic risk factors, like N-BPs, anti-RANKL antibodies, or AgIs. Specific local oral risk factors first noted in humans, including tooth extraction and inflammatory dental disease (e.g., periodontitis, periapical infection, etc.), were then added. Research in rodents, particularly the rat, and, to some extent, the mouse, across multiple laboratories, has contributed to establishing multiple relevant and complementary preclinical models. Models in larger species produced accurate clinical and histopathologic outcomes suggesting a potential role for confirming specific crucial findings from rodent research. We view the current state of animal models for MRONJ as good. The rodent models are now reliable enough to produce large numbers of MRONJ cases that could be applied in experiments testing treatment modalities. The course of MRONJ, including stage 0 MRONJ, is characterized well enough that basic studies of the molecular or enzyme-level findings in different MRONJ stages are possible. This review provides a current overview of the existing models of MRONJ, their more significant features and findings, and important instances of their application in preclinical research.

Review and Update of the Risk Factors and Prevention of Antiresorptive-Related Osteonecrosis of the Jaw

Antiresorptive-related osteonecrosis of the jaw (ARONJ) is a rare but serious adverse event of bisphosphonate or denosumab administration; it is associated with severe pain and a deteriorated quality of life. Since its first report in 2003, there have been many studies on its definition, epidemiology, pathophysiology, diagnosis, and treatment. Nevertheless, the epidemiology and mechanisms underlying this condition have not yet been fully delineated and several risk factors are known. Moreover, as there is no effective treatment currently available for osteonecrosis of the jaw, prevention is essential. Furthermore, close cooperation between prescribing physicians and dentists is important. The aim of this review was to provide up-to-date information regarding the risk factors and prevention of ARONJ from a physician's perspective.

Oral Surgery Procedures in a Patient with Hajdu-Cheney Syndrome Treated with Denosumab-A Rare Case Report

Background: Hajdu-Cheney syndrome (HCS) is a very rare autosomal-dominant congenital disease associated with mutations in the NOTCH2 gene. This disorder affects the connective tissue and is characterized by severe bone resorption. Hajdu-Cheney syndrome most frequently affects the head and feet bones (acroosteolysis). Case report: We present an extremely rare case of a 34-year-old male with Hajdu-Cheney syndrome. The patient was admitted to the Department of Oral Surgery, Medical University of Gdańsk, in order to perform the extraction of three teeth. These teeth were not eligible for conservative treatment and prosthetic reconstruction. The patient was treated with denosumab (angiogenesis and receptor activator of nuclear factor-κB RANK ligand inhibitor, RANKL). Discussion: Denosumab is a monoclonal antibody against RANKL. This drug works through a suppression of osteoclast activity. In cases of patients in which the pathway of the RANK/RANKL/osteoprotegerin is dysregulated, denosumab has been approved for the treatment off-label. In patients receiving denosumab, a delayed wound healing in the oral cavity and osteonecrosis may occur. Dental procedures involving the alveolar bone process (tooth extractions and bone alveoloplasty) may be a risk factor for medication-related osteonecrosis of the jaw (MRONJ). Spontaneous osteonecrosis is rarely observed. MRONJ consists of the destruction of exposed bone, with the exposure persisting for a minimum of 6–8 weeks. This is the first article about an HCS patient treated with denosumab who underwent invasive oral surgery procedures. This case report highlights the difficulties for professionals occurring during the oral surgery procedures in such patients.

Lack of evidence in reducing risk of MRONJ after teeth extractions with systemic antibiotics

A systematic review was carried out to identify if periprocedural administration of systemic antibiotics could decrease risk of medication-related osteonecrosis of the jaws (MRONJ) in patients under antiresorptive and/or biologic agents for teeth extraction. PubMed/MEDLINE and Scopus were systematically searched for case-series with more than 10 patients, retrospective/prospective studies, and trials concerning this issue. Manual searching of references from previous reviews was also carried out. Of 1,512 results, 17 studies were included, focusing on antibiotics for extraction in patients under intravenous bisphosphonates (8 studies), oral bisphosphonates (2 studies), oral and intravenous bisphosphonates (6 studies), and denosumab (1 study), of which 12 performed dental extraction with surgical flap. With no trials found, "quality in prognosis studies" (QUIPS) tool was used to evaluate risk of bias. First-line treatment was 2-3 grams of oral amoxicillin in 76.4% of studies; 300-600 mg of clindamycin was the alternative treatment in 23.5% of studies. Treatment ranged from 3 to 20 days, consisting of 6-7 days in 47% of studies. No microbiologic insight was provided. A significantly higher risk of MRONJ for patients unexposed to antibiotics was provided in one retrospective study. QUIPS tool revealed moderate-high risk of bias. With empirical data from bias-carrying, heterogeneous observational studies, the validity of antibiotics is yet to be established.

Oral health condition in cancer patients under bisphosphonate therapy

OBJECTIVES

To investigate the association of oral health condition with the occurrence of medication-related osteonecrosis of the jaw (MRONJ) in a cancer population.

METHODS

A multicenter cross-sectional study was conducted with cancer patients exposed to bisphosphonates for at least 7 months. Dental and periodontal conditions were assessed by epidemiological indices.

RESULTS

The sample consisted of 80 patients under bisphosphonate therapy, nine of which were allocated to group 1 (with MRONJ) and 71 to group 2 (without MRONJ). Osteonecrosis cases presented 19 decayed, missing, and filled teeth on average. Moderate gingival inflammation was noted in both groups and together with severe inflammation exceeded 50% of the groups. The presence of dental calculus was detected in about half of the individuals in both groups. Shallow periodontal pockets were detected in about 25% of both groups. Deep periodontal pockets were more prevalent among patients with osteonecrosis. Regular oral hygiene was detected in approximately 25% of individuals in both groups. There was a strong positive correlation between the clinical staging of osteonecrosis and decayed, missing, and filled teeth index (DMFTI).

CONCLUSIONS

Patients had a poor oral health condition. All but one osteonecrosis case had no previous history of tooth extraction; oral infections seemed to play a major role in the development of bone necrosis. Advanced osteonecrosis stages were associated with a higher DMFTI.

Medication-related osteonecrosis of the jaw: Osteoclast profile in comparison with osteoradionecrosis of the jaw and osteomyelitis of the jaw

BACKGROUND

Medication-related osteonecrosis of the jaw (MRONJ) is a pathology condition of jaw bone caused by a side effect of medications prescribed for skeletal disease. The mechanism of MRONJ is still unknown now. Osteoclasts are cells directly influenced by the medication and the modification in cells metabolisms by the drugs lead to MRONJ. Thus, this study aimed to investigate the osteoclasts morphology, quantity, and comparing with other necrotic diseases.

METHODS

Thirty-eight (38) subjects, including cases with MRONJ (n = 11), osteoradionecrosis of the jaw (n = 9), osteomyelitis of the jaw (n = 9), and normal jaw bone (n = 9), were studied. Hematoxylin-and-eosin-stained slides of these diagnosed cases were used to evaluate osteoclasts' characteristics. Immunohistochemistry of TRAP was performed to observed the function of osteoclasts. These characteristics of osteoclasts were also evaluated in the relationship with the histological features using regression analysis.

RESULTS

The results showed that osteoclasts in MRONJ enhance activity by increasing the size and the quantity (p < 0.05). The presence of osteoblasts, inflammatory cells, and bacterial colonies showed a strong correlation with the change in morphology and the number of osteoclasts (p < 0.05). However, the TRAP-positive mean number and the TRAP intensity of osteoclasts in MRONJ did not show a significant difference with those in other groups (p > 0.05).

CONCLUSION

In conclusion, osteoclasts in MRONJ increase the number and become bigger with multi-nuclei which might relate to the presence of osteoblasts, inflammation, and microorganisms. This finding supports the idea osteoclasts might be the main key to investigate MRONJ.

Bisphosphonates in dentistry: Historical perspectives, adverse effects, and novel applications

Studies of the potential role of bisphosphonates in dentistry date back to physical chemical research in the 1960s, and the genesis of the discovery of bisphosphonate pharmacology in part can be linked to some of this work. Since that time, parallel research on the effects of bisphosphonates on bone metabolism continued, while efforts in the dental field included studies of bisphosphonate effects on dental calculus, caries, and alveolar bone loss. While some utility of this drug class in the dental field was identified, leading to their experimental use in various dentrifice formulations and in some dental applications clinically, adverse effects of bisphosphonates in the jaws have also received attention. Most recently, certain bisphosphonates, particularly those with strong bone targeting properties, but limited biochemical effects (low potency bisphosphonates), are being studied as a local remedy for the concerns of adverse effects associated with other more potent members of this drug class. Additionally, low potency bisphosphonate analogs are under study as vectors to target active drugs to the mineral surfaces of the jawbones. These latter efforts have been devised for the prevention and treatment of oral problems, such as infections associated with oral surgery and implants. Advances in the utility and mechanistic understanding of the bisphosphonate class may enable additional oral therapeutic options for the management of multiple aspects of dental health.

Medication-related osteonecrosis of the jaw (MRONJ) and eNOS Polymorphisms in multiple myeloma patients: a single center experience

Background

Multiple myeloma (MM) constitutes approximately 10% of hematological malignancies. Bisphosphonates have established themselves in solid organ metastasis and multiple myeloma lytic bone lesions by inhibiting osteoclast activation. Medication-related osteonecrosis of the jaw (MRONJ) emerges as an important complication. Investigating host-based factors, and developing personal risk factors gain importance in the development mechanism of MRONJ. We aimed to reveal the different genotype polymorphisms, and clinical effects of eNOS in patients with a diagnosis of MRONJ in MM patients.

Methods

Medical records and blood samples were collected from 60 MRONJ patients with MM and 60 healthy controls. Inclusion criteria was having an exposed maxillofacial bone for more than eight weeks, a history of bisphosphonates, and no history of radiation therapy for the jaws. eNOS G894T and intron 4 VNTR were calculated by polymerase chain reaction and/or restriction fragment length polymorphism.

Results

eNOS G894T and VNTR genotypes and alleles were compared statistically with the healthy control group. There was no significant difference between the two groups. In comparison between G894T and clinical parameters, aphthous stomatitis was more common in TT genotype, while DMFT > 3 was more common in TG-GG genotype (p = 0.035, 0.023).

Conclusions

eNOS induces osteogenesis in bone metabolism, with its regulatory effects on bone remodeling and also NO induced angiogenesis takes place indirectly with its protective effect on endothelial functions. We see that these polymorphisms affecting the entire process of bone remodeling and angiogenesis, especially mucosal damage, which is the triggering factor of MRONJ pathology, have been revealed in the MM patient group. Considering the MRONJ initiating factors, it is necessary to emphasize the importance of our study results. It should be seen as an important step for new studies towards MRONJ and its treatment.

Infection as an Important Factor in Medication-Related Osteonecrosis of the Jaw (MRONJ)

Medication-related osteonecrosis of the jaw (MRONJ) has become a well-known side effect of antiresorptive, and antiangiogenic drugs commonly used in cancer management. Despite a considerable amount of literature addressing MRONJ, it is still widely accepted that the underlying pathomechanism of MRONJ is unclear. However, several clinical and preclinical studies indicate that infection seems to have a major role in the pathogenesis of MRONJ. Although there is no conclusive evidence for the infection hypothesis yet, available data have shown a robust association between local infection and MRONJ development. This observation is very critical in order to implement policies to reduce the risk of MRONJ in patients under antiresorptive drugs. This critical review was conducted to collect the most reliable evidence regarding the link between local infection and MRONJ pathogenesis.

Proposal for a preventive protocol for medication-related osteonecrosis of the jaw

Background

Medication-related osteonecrosis of the jaw (MRONJ) is a severe adverse reaction experienced by some patients exposed to certain drugs (antiresorptives such as bisphosphonates or denosumab, and antiangiogenic drugs). From a review of the literature it appears that there is no uniform criterion when selecting preventive measures; these vary according to author. Likewise, the measures recommended are usually general, so that in few cases they result in specific actions to be applied depending on the different variables involved such as the type of drug used, the duration of its application, the underlying pathology, the presence or absence of risk factors, etc. The aim of this study has been to design a preventive protocol which can be easily applied in any clinic or by any dental care service.

Material and Methods

We undertook an exhaustive literature review to find any articles related to the topic of study, namely, preventive measures for medication-related osteonecrosis of the jaw, on the one hand generically and on the other focusing on dental implant treatment. The most part the criteria of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed. From 3946 items, we selected a total of 21 items.

Results

From the analysis of the selected articles, several protocols have been developed that are easy to apply in a dental clinic.: Protocol 1. Before starting treatment with antiresorptives (Patients who are going to be treated for osteoporosis / Patients who are going to be treated for cancer). Protocol 2. Once treatment is initiated with antiresorptives (Patients being treated for osteoporosis / Patients being treated for cancer).

Conclusions

The application of these protocols requires an interdisciplinary team which can handle the various treatments and apply the measures contained in them. Along with a team of well-educated and trained dentists, it is equally important to maintain contact with the medical team involved in the treatment of the underlying pathology, especially rheumatologists, oncologists, internists and gynaecologists. All the above requires a great staff learning and organization effort, continuous training and coordination of the whole team involved in the preventive management of these patients.

Key words:Medication-related osteonecrosis of the jaw, clinical protocols, clinical guidelines, prevention.

Preventing or controlling periodontitis reduces the occurrence of osteonecrosis of the jaw (ONJ) in rice rats (Oryzomys palustris)

INTRODUCTION

Osteonecrosis of the jaw (ONJ) is an adverse event that requires association of both systemic risk factors, such as powerful anti-resorptives (pARs; e.g. zoledronic acid [ZOL]), and local oral risk factors (e.g. tooth extraction, periodontitis). Whereas optimal oral health prior to initiate pARs is recognized as critically important for minimizing ONJ risk, the efficacy of preventive/maintenance measures in patients who are taking pARs is understudied. Rice rats fed a standard diet (STD), rich in insoluble fiber, develop localized periodontitis. STD-rats with localized periodontitis treated with ZOL for 18-24 wk develop ONJ. Hence, we hypothesized that controlling/preventing localized periodontitis in the ZOL-treated rats, reduces ONJ occurrence.

METHODS

We used two approaches to attempt reducing periodontitis prevalence: 1) periodontal cleaning (PC); and 2) replacing the STD-diet with a nutritionally-equivalent diet high in soluble fiber (SF). 75 four-week-old male rats were weight-randomized into five groups (n = 15) in a 24-week experiment. Three groups ate the STD-diet and two the high SF-diet. STD-diet groups received intravenous (IV) vehicle (VEH) q4wks (STD + VEH), 80 μg/kg ZOL q4wks IV (STD + ZOL), or ZOL plus PC q2wks (STD + ZOL + PC). The SF-diet groups received VEH (SF + VEH) or ZOL (SF + ZOL). Jaws were processed for histopathology and evaluated for ONJ prevalence and tissue-level periodontitis.

RESULTS

1) 40% of STD + VEH rats developed maxillary localized periodontitis with no ONJ; 2) 50% of STD + ZOL rats developed ONJ; 3) 7% of STD + ZOL + PC rats developed ONJ (p < 0.01 vs. STD + ZOL); and 4) one SF + ZOL rat developed localized periodontitis, and no SF + VEH or SF + ZOL rats developed ONJ (p < 0.001 vs. STD + ZOL).

CONCLUSIONS

1) Periodontal cleaning in ZOL-treated rats decreases localized periodontitis severity and reduces ONJ prevalence; and 2) feeding a SF-diet to ZOL-treated rats reduces both incidence of localized periodontitis and ONJ. Our data indicates strong oral microbial community shifts according to oral health condition and trends in the shifts associated with diet.

Bisphosphonate application and volumetric effects on MRONJ lesions

The purpose of this investigation was to analyze the volume of medication-related osteonecrosis of the jaw (MRONJ) lesions by semi-automatic segmentation of cone-beam computed tomography images, and correlate the results with the underlying diseases and applied medication. MRONJ lesions detected in cone-beam computed tomography images were assessed. The open-source software ITK-Snap enabled volumetric measurements of MRONJ lesions based on semi-automatic segmentation. Results were analyzed according to necrosis volume, localization, and gender. In addition, the underlying disease and the type of application of antiresorptive medication were investigated. Cone-beam computed tomography images of 66 patients were studied. 34 male and 32 female patients were included, with ages ranging from 50 to 93 years at the time of diagnosis. The mean volume was 993.24 ± 620.94 mm³: 484.73 ± 230.97 mm³ for the upper jaw and 1084.04 ± 625.74 mm³ for the lower jaw. The results indicated statistically significant differences between lesions of the upper and lower jaw, regardless of gender (p = 0.003). The analysis of differences between males and females did not show any significant results (p = 0.464), although males presented slightly larger lesions than females. With regard to the underlying disease, patients with osteoporosis presented larger volumes, whereas patients with malignant tumors presented smaller volumes. Nevertheless, no statistically significant differences according to the underlying disease (p = 0.313) were detected. However, patients with intravenous (iv) application showed statistically significantly larger lesions than patients who underwent oral or subcutaneous (s.c.) applications (p = 0.004). It seems that the osteonecrosis volume correlates with the applied antiresorptive agents. Larger MRONJ lesions should be expected in patients who receive intravenous antiresorptive therapy.

Bisphosphonate-Related Osteonecrosis of the Jaw

OBJECTIVES

Antiresorptive agents for bone pain were widely used to treat patients with advanced osteoporosis, multiple myeloma, and bone metastatic cancer. In recent years, however, bisphosphonate-related osteonecrosis of the jaw (BRONJ) has been a rare but major complication of this therapy. Most patients with BRONJ undergo dental procedures during treatment with antiresorptive agents. However, BRONJ may also occur spontaneously. This study reports 13 BRONJ patient cases at Kaohsiung Veterans General Hospital, Taiwan, and their related treatments. We also compare patients with cancer with patients with osteoporosis in treatment outcomes.

METHODS

Thirteen symptomatic patients with BRONJ were reviewed between 1985 and 2018 at Kaohsiung Veterans General Hospital. We included patients at advanced stage who were hospitalized for infection control of osteonecrosis of the jaw and excluded asymptomatic patients at stage 0 and stage 1. Four multiple myeloma, 3 patients with bone metastatic breast cancer and 6 patients with advanced osteoporosis (average ages, 63.57 ± 14.54 years in cancer patients and 79.5 ± 9.31 years in osteoporosis patients; average drug durations, 25.86 ± 27.23 months in cancer patients and 58.33 ± 23.87 months in osteoporosis patients; average follow-up times, 22.71 ± 14.46 months in cancer patients and 28.08 ± 36.35 months in osteoporosis patients) were included.

RESULTS

Seven patients were defined as having stage 3 (53.8%) and 6 as having stage 2 (46.2%) medication-related osteonecrosis of the jaw, according to the American Association of Oral and Maxillofacial Surgeons classification. The complete response rate with totally healed mucosa was 61.5%. Four cancer patients received free fibular flap (FFF) reconstruction with a high complete response rate (100%). All of them had a relatively better performance status, and the average age was also younger than osteoporosis patients.

CONCLUSION

Free fibular flap with a high complete response rate may improve pain relief and infection control for patients with BRONJ. Younger age is seemed to be a great indicator for FFF, but poor self-care ability (Eastern Cooperative Oncology Group status >3) is not suitable for these surgical treatments.

Assessment of jaw osteonecrosis diagnostic criteria in cancer patients with a history of radiation therapy and exposure to bone-modifying agents

BACKGROUND

Osteoradionecrosis (ORN) of the jaw is currently defined by the development of osteonecrosis in head/neck irradiated patients, regardless of lesion exposure. To diagnose medication-related osteonecrosis of the jaw (MRONJ), a history of any radiation therapy to the jaw region must be ruled out. The aim of this study was to assess the accuracy of current osteonecrosis criteria, while introducing new modifications for improved diagnosis and treatment.

METHODS

One hundred and forty-one necrotic lesions were analyzed from patients exposed to bone-modifying agents (BMAs) and/or received head and neck regional radiation therapy, where the maximal dose of radiation exposure to the jaw osteonecrosis site was calculated. Modified diagnostic criteria were used to reassess all cases and a comparison of outcomes was performed using Pearson's Chi-Square/Fisher's exact test.

RESULTS

Only in patients with primary head and neck carcinomas did the maximal mean radiation dose in the necrotic jaw site reach ranges associated with ORN formation (>40 Gy), with individual cases showing exposures as low as 0-2 Gy. Based on the modified diagnostic criteria almost 2/3 of the necrotic cases diagnosed as ORN should be diagnosed as MRONJ.

CONCLUSIONS

ORN diagnosis should only be considered in cases of radiation exposure >40 Gy to prevent misdiagnosis and suboptimal treatment. A modified criterion for MRONJ diagnosis is recommended where radiation exposure <40 Gy in the necrotic site is included. In cases with exposure >40 Gy and BMA administration, an additional modification to diagnostic criteria of 'medication- and radiation-related osteonecrosis of the jaw', should be used.

Network pharmacology-based investigation on the mechanisms of action of Morinda officinalis How. in the treatment of osteoporosis

BACKGROUND

Osteoporosis is a systemic skeletal disease that leads to a high risk for bone fractures. Morinda officinalis How. has been used as osteoporosis treatment in China. However, its mechanism of action as an anti-osteoporotic herb remains unknown.

METHODS

A network pharmacology approach was applied to explore the potential mechanisms of action of M. officinalis in osteoporosis treatment. The active compounds of M. officinalis and their potential osteoporosis-related targets were retrieved from TCMSP, TCMID, SwissTargetPrediction, DrugBank, DisGeNET, GeneCards, OMIM, and TTD databases. A protein-protein interaction network was built to analyze the target interactions. The Metascape database was used to carry out GO enrichment analysis and KEGG pathway analysis. Moreover, interactions between active compounds and potential targets were investigated through molecular docking.

RESULTS

A total of 17 active compounds and 93 anti-osteoporosis targets of M. officinalis were selected for analysis. The GO enrichment analysis results indicated that the anti-osteoporosis targets of M. officinalis mainly play a role in the response to steroid hormone. The KEGG pathway enrichment analysis showed that M. officinalis prevents osteoporosis through the ovarian steroidogenesis signaling pathway. Moreover, the molecular docking results indicated that bioactive compounds (morindon, ohioensin A, and physcion) demonstrated a good binding ability with IGF1R, INSR, ESR1, and MMP9.

CONCLUSION

M. officinalis contains potential anti-osteoporotic active compounds. These compounds function by regulating the proteins implicated in ovarian steroidogenesis-related pathways that are crucial in estrogen biosynthesis. Our study provides new insights into the development of a natural therapy for the prevention and treatment of osteoporosis.

Surgical Management of Medication-Related Osteonecrosis of the Jaw Patients Related to Dental Implants

OBJECTIVES

The aim of the present study is to report a case series of patients with peri-implant medication-related osteonecrosis of the jaw (MRONJ), in particular describing the onset of the condition and surgical treatment outcome.

MATERIAL AND METHODS

Fifteen consecutive patients with clinical diagnosis of peri-implant MRONJ were retrospectively included in the study. The sample was stratified on the base of oral, pharmacological, and general health variables. The number of affected implants was recorded in all patients, and MRONJ staging applied. Surgical treatment was performed with a standardized operative protocol, involving implant removal, sequestrectomy, debridement of soft tissue, and bone curettage. Follow-up evaluating surgical outcome was performed at twelve months after surgery.

RESULTS

in our study sample, patients were almost equally distributed in terms of underlying diseases in osteoporotic and oncologic patients. All MRONJ lesions were symptomatic, and in 6 patients bone exposure was detected. 40 implants in total were evaluated, with MRONJ being present around 29 implants. 12 patients were diagnosed with Stage III MRONJ, and 3 patients with Stage II MRONJ. Surgical treatment leads to complete healing in 86.7% of cases, with 100% success for maxillary MRONJ.

CONCLUSIONS

Surgical treatment seems to have a positive impact on MRONJ treatment also in cases of peri-implant involvement. However, monitoring and prevention are fundamental in patients under pharmacological treatment with anti-resorptive/antiangiogenic drugs, as peri-implant MRONJ can develop also in absence of specific traumatic events.

Necrotizing periodontitis or medication-related osteonecrosis of the jaw (MRONJ) in a patient receiving Bemcentinib-a case report

Bemcentinib is a newly developed AXL inhibitor that is currently under investigation in phase II trails for the treatment of acute myeloblastic leukemia (AML). Clinical and radiographic findings in this case were very similar to cases of MRONJ in patients receiving Sunitinib or other anti-angiogenetic substances, assuming that Bemcentinib may cause similar oral side effects. We present a male 81-year-old patient with a manifestation of alveolar bone necrosis at the central upper incisors following a 2-month regimen with the AXL-inhibitor Bemcentinib, administered for the treatment of secondary acute myeloblastic leukemia (sAML). Due to the duration of less than 8 weeks, the osteonecrosis was diagnosed as necrotizing periodontitis, but the intraoral clinical and radiographic findings were also compatible with the differential diagnosis of medication-related osteonecrosis of the jaw (MRONJ, stage II). Following to discontinuation of Bemcentinib, the affected bone was surgically revised including the removal of a demarcated bone sequester under preventive antibiotic treatment (metronidazole 400 mg t.i.d.). We hypothesize that Bemcentinib might increase the susceptibility for osteonecrosis of the jaw, probably related to its antiangiogenic effects and the resulting modulation of host immune response. Based on the current observations, it can be assumed that oro-dental health might be significant also prior and during treatment with Bemcentinib for the prevention of MRONJ.

Awareness among patient at risk of developing Medication Related Osteonecrosis of the Jaw (MRONJ) - A primary prevention strategy

The quality of life, in itself, in cancer patients or in osteoporotic individuals, without even considering the side effects of the medication in the first place, has a considerable negative impact on the clinical outcome. The Medication Related Osteonecrosis of the Jaw (MRONJ), in the maxillofacial region, although rare, needs to be addressed with the prime importance. One of the key components of any given preventive treatment strategy is to, create awareness about the medication related unwanted effects, among health care professionals and patients.

Objective

This study is aimed to explore and assess the awareness level among dental patients about MRONJ, the risk factors, and the high-risk category (who are prone to develop MRONJ).

Material and methods

This is a prospective interviewer administered research electronic data capture (REDCap) survey. The sample included 68 patients, who are currently taking or will be taking Bisphosphonate (BP), and/or Denosumab, and anti-Angiogenic agent. Data have been analyzed using IBM SPSS software,

Results

Sixty-eight patients (18 males and 50 females), participated in this study. Only 23 subjects (33.82%) were aware about the MRONJ. Females were more aware about the complications than males. The awareness among the subjects with education at college level appears to be higher than the subjects having education less than high school level. Even though, a dental check- up, is mandatory, prior to starting these medications, to see if any dental treatment is required, only slightly more than half of the patients (54.72%) had a dental checkup.

Conclusion

This is a novel study in the Middle- East, used to assess awareness about the MRONJ including three type of related medications. Low awareness of MRONJ is alarming. The results of the study will help to initiate the process of providing the education materials, about the side effects and importance of oral hygiene maintenance, giving priority to improve the quality of life in such patients. Awareness of patients regarding the complications must be an important part of health care practice guidelines.

The fungal metabolite (+)-terrein abrogates osteoclast differentiation via suppression of the RANKL signaling pathway through NFATc1

Pathophysiological bone resorption is commonly associated with periodontal disease and involves the excessive resorption of bone matrix by activated osteoclasts. Receptor activator of nuclear factor (NF)-κB ligand (RANKL) signaling pathways have been proposed as targets for inhibiting osteoclast differentiation and bone resorption. The fungal secondary metabolite (+)-terrein is a natural compound derived from Aspergillus terreus that has previously shown anti-interleukin-6 properties related to inflammatory bone resorption. However, its effects and molecular mechanism of action on osteoclastogenesis and bone resorption remain unclear. In the present study, we showed that 10 µM synthetic (+)-terrein inhibited RANKL-induced osteoclast formation and bone resorption in a dose-dependent manner and without cytotoxicity. RANKL-induced messenger RNA expression of osteoclast-specific markers including nuclear factor of activated T-cells cytoplasmic 1 (NFATc1), the master regulator of osteoclastogenesis, cathepsin K, tartrate-resistant acid phosphatase (Trap) was completely inhibited by synthetic (+)-terrein treatment. Furthermore, synthetic (+)-terrein decreased RANKL-induced NFATc1 protein expression. This study revealed that synthetic (+)-terrein attenuated osteoclast formation and bone resorption by mediating RANKL signaling pathways, especially NFATc1, and indicated the potential effect of (+)-terrein on inflammatory bone resorption including periodontal disease.

Replacing one evil with another: Is the fibula really a dispensable spare part available for transfer in patients with medication-related osteonecrosis of the jaws?

Because of the long-term and consecutive use of different causative agents, clinicians are increasingly encountering patients needing restoration of the stomatognathic system after surgical resection of highly advanced necroses of the jaw. For plastic restoration in these cases, microvascular reconstruction seems to represent the most viable option. According to the limited data available, the risks of this operation are considered comparable with those faced by other patient cohorts. We report here the case of a patient who suffered 2 successive pathologic fractures of the tibia after microsurgical reconstruction of the mandible with a free fibula flap. This exemplifies a general problem, especially because the patient also suffered from a treatment-refractory infection of the transplanted bone. Although the present literature indicates otherwise, fibula transplants might not be the gold standard in these cases. Therefore, alternatives to transplants from the weight-bearing parts of the body need to be considered until more data are available.

Indigenous Microbiota Protects against Inflammation-Induced Osteonecrosis

Medication-related osteonecrosis of the jaw (MRONJ) is a rare intraoral lesion that occurs in patients undergoing long-term and/or high-dose therapy with nitrogen-containing bisphosphonates, a RANKL inhibitor, antiangiogenic agents, or mTOR inhibitors. The presence of pathogenic bacteria is highly associated with advanced stages of MRONJ lesions; however, the exact role of indigenous microbes in MRONJ development is unknown. Here, we report that the normal oral flora in mice protects against inflammation-induced osteonecrosis. In mice that developed osteonecrosis following tooth extraction, there was increased bacterial infiltration when compared with healed controls. Antibiotic-mediated oral dysbiosis led to a local inhibition of bone resorption in the presence of ligature-induced periodontitis (LIP). There was no significant difference in empty lacunae, necrotic bone formation, osteoclast number, and surface area in antibiotic-treated as compared with conventionally colonized mice following extraction of healthy teeth after zoledronic acid infusions. However, extraction of LIP teeth led to increased empty lacunae, necrotic bone, and osteoclast surface area in antibiotic- and zoledronic acid-treated mice as compared with conventionally colonized mice. Our findings suggest that the presence of the indigenous microbiota protects against LIP-induced osteonecrosis.

The effects of different doses of teriparatide on bisphosphonate-related osteonecrosis of the jaw in mice

OBJECTIVES

This study aimed to investigate the therapeutic effect of different doses of teriparatide (TPTD) on bisphosphonate-related osteonecrosis of the jaw (BRONJ).

MATERIALS AND METHODS

To establish the BRONJ model, 20 mice were randomly divided into two groups: a group that received tail vein administration of zoledronic acid with dexamethasone (ZA-125 µg/kg, DEX 5 mg/kg) and a group that received saline weekly. The mice subsequently underwent bilateral maxillary first molar extraction. After 8 weeks of modelling administration, the maxilla samples were examined by micro-computed tomography and histological staining (haematoxylin and eosin, Masson's trichrome and tartrate-resistant acid phosphatase) and the cytokine level was measured (enzyme-linked immunosorbent assay and Western blot). To determine the role of TPTD in BRONJ, the same protocol as previously described was applied in 100 mice (80 received ZA + DEX, and 20 received saline). After 8 weeks of modelling administration, 80 ZA + DEX mice were randomly divided into four groups: three groups with subcutaneous administration of TPTD (i.e. T1-3, T2-10 and T3-30 µg kg^-1  day^-1 ) and one group with saline daily for the next 8 weeks. The other 20 saline mice continued to receive saline daily.

RESULTS

In Part 1, the level of receptor activator of nuclear factor-kappa Β ligand and the numbers of osteoclasts differed between the model and control groups. In Part 2, we found that TPTD had a positive effect on BRONJ in a mouse model based on clinical and histomorphological observations. Among the three treatment groups, the T1 and T2 groups significantly differed from the model group, whereas the T3 group showed no statistical differences.

CONCLUSION

Subcutaneous administration of TPTD has a beneficial effect on BRONJ in mice. Nevertheless, further studies are needed to determine whether the therapeutic effect on BRONJ is dose-dependent.