Various Therapeutic Methods for the Treatment of Medication-Related Osteonecrosis of the Jaw (MRONJ) and Their Limitations: A Narrative Review on New Molecular and Cellular Therapeutic Approaches

A Systematic Review of Laser Photobiomodulation Dosimetry and Treatment Protocols in the Management of Medications-Related Osteonecrosis of the Jaws: A Rationalised Consensus for Future Randomised Controlled Clinical Trials

Medication-related osteonecrosis of the jaw (MRONJ) is a debilitating adverse effect of bisphosphates, antiresorptive therapy or antiangiogenic agents that can potentially increase oxidative stress, leading to progressive osteonecrosis of the jaws. Despite the large number of published systematic reviews, there is a lack of potential MRONJ treatment protocols utilising photobiomodulation (PBM) as a single or adjunct therapy for preventive or therapeutic oncology or non-oncology cohort. Hence, this systematic review aimed to evaluate PBM laser efficacy and its dosimetry as a monotherapy or combined with the standard treatments for preventive or therapeutic approach in MRONJ management. The objectives of the review were as follows: (1) to establish PBM dosimetry and treatment protocols for preventive, therapeutic or combined approaches in MRONJ management; (2) to highlight and bridge the literature gaps in MRONJ diagnostics and management; and (3) to suggest rationalised consensus recommendations for future randomised controlled trials (RCTs) through the available evidence-based literature. This review was conducted according to the PRISMA guidelines, and the protocol was registered at PROSPERO under the ID CRD42021238175. A multi-database search was performed to identify articles of clinical studies published from their earliest records until 15 December 2023. The data were extracted from the relevant papers and analysed according to the outcomes selected in this review. In total, 12 out of 126 studies met the eligibility criteria. The striking inconsistent conclusions made by the various authors of the included studies were due to the heterogeneity in the methodology, diagnostic criteria and assessment tools, as well as in the reported outcomes, made it impossible to conduct a meta-analysis. PBM as a single or adjunct treatment modality is effective for MRONJ preventive or therapeutic management, but it was inconclusive to establish a standardised and replicable protocol due to the high risk of bias in a majority of the studies, but it was possible to extrapolate the PBM dosimetry of two studies that were close to the WALT recommended parameters. In conclusion, the authors established suggested rationalised consensus recommendations for future well-designed robust RCTs, utilising PBM as a monotherapy or an adjunct in preventive or therapeutic approach of MRONJ in an oncology and non-oncology cohort. This would pave the path for standardised PBM dosimetry and treatment protocols in MRONJ management.

Role of O-linked N-acetylglucosamine protein modification in oxidative stress-induced autophagy: a novel target for bone remodeling

O-linked N-acetylglucosamine protein modification (O-GlcNAcylation) is a dynamic post-translational modification (PTM) involving the covalent binding of serine and/or threonine residues, which regulates bone cell homeostasis. Reactive oxygen species (ROS) are increased due to oxidative stress in various pathological contexts related to bone remodeling, such as osteoporosis, arthritis, and bone fracture. Autophagy serves as a scavenger for ROS within bone marrow-derived mesenchymal stem cells, osteoclasts, and osteoblasts. However, oxidative stress-induced autophagy is affected by the metabolic status, leading to unfavorable clinical outcomes. O-GlcNAcylation can regulate the autophagy process both directly and indirectly through oxidative stress-related signaling pathways, ultimately improving bone remodeling. The present interventions for the bone remodeling process often focus on promoting osteogenesis or inhibiting osteoclast absorption, ignoring the effect of PTM on the overall process of bone remodeling. This review explores how O-GlcNAcylation synergizes with autophagy to exert multiple regulatory effects on bone remodeling under oxidative stress stimulation, indicating the application of O-GlcNAcylation as a new molecular target in the field of bone remodeling.

Examination of certain single-nucleotide polymorphisms of interleukins 1A and 1B in medication-related osteonecrosis of the jaw - An ambirectional cohort study

AIM

The aim of this study was to examine particular single-nucleotide polymorphisms (IL-1A-889 C/T - rs1800587, IL-1B +3953 C/T - rs 1143634) of interleukins 1A and 1B in the development and prognosis of medication-related osteonecrosis of the jaw.

MATERIALS AND METHODS

DentiGen Parodontitis Tests were applied for collecting samples. This test is suitable for sampling oral mucosa cells in order to detect interleukins 1A and 1B single nucleotide polymorphisms (IL-1A-889, IL-1B+3953). Genetic samples were evaluated in the Istenhegyi Genediagnostic Center using the DNA-hybridization method. Genetic samples were collected in the patient group and the control group. The role of gene polymorphisms in the development of the disease was investigated by comparing the genetic results for the patient and control groups. The investigation of gene polymorphisms in disease prognosis is based on stage improvement, recovery, and relapses following treatment.

RESULTS

In total, 91 patients with MRONJ and 59 healthy controls were included in the study. 51 patients in the patient group and 37 controls had unfavorable allelic variants. No association (Mp = 1.42, SDp = 0.496, Mc = 1.35, SDc = 0.482, p = 0.52) was found between unfavorable polymorphisms and the development of the MRONJ. In the patient group, surgical therapy was required in 79 cases. Stage improvement was detected in 78 cases, recovery in 67 cases, and relapse in 33 cases. No stage improvement was found in one case, recovery in nine cases, or relapse in 34 cases. Of the 79 patients requiring surgical therapy, 49 had unfavorable allelic variants. No connection was found between the polymorphisms examined and stage improvement (Mp = 1.37, SDp = 0.486, Mnp = 2, SDnp = -, p = 0.800) or recovery (Mp = 1.39, SDp = 0.491, Mnp = 1.44, SDnp = 0.527, p = 0.990). However, a significant association (Mp = 1.21, SDp = 0.415, Mnp = 1.58, SDnp = 0.502, p < 0.001) was found between relapses and the presence of unfavorable allelic variants.

CONCLUSION

Within the possible limitations of this study, it can be assumed that the analysis of certain single-nucleotide polymorphisms of interleukin-1 may have the potential to help define the risk stratification of MRONJ after surgical therapy.

Medication-related osteonecrosis of the jaw: evolving research for multimodality medical management

PURPOSE

Medication-related osteonecrosis of the jaw (MRONJ) is a debilitating side effect of antiresorptive and antiangiogenic agents that can lead to progressive bone destruction in the maxillofacial region. Dental surgery, including tooth extractions, commonly trigger the onset of MRONJ. While guidelines suggest avoiding extraction when possible, complete avoidance is not always feasible, as necrosis can develop from dental and periodontal disease without dental procedures. The goal of this article is to provide an update review of current preventive and therapeutic approaches for MRONJ.

METHODS

A comprehensive electronic search was conducted on PubMed/MEDLINE, Embase, and Scopus databases. All English articles encompassing randomized controlled trials, systematic reviews, observational studies, and case studies were reviewed. The current medical treatments and adjuvant therapies for managing MRONJ patients were critically assessed and summarized.

RESULTS

Pentoxifylline and alpha tocopherol (PENT-E), teriparatide, photobiomodulation (PBM), photodynamic therapy (PDT), and the use of growth factors have shown to enhance healing in MRONJ patients. Implementing these methods alone or in conjunction with surgical treatment has been linked to reduced discomfort and improved wound healing and increased new bone formation.

DISCUSSION

While several adjuvant treatment modalities exhibit promising results in facilitating the healing process, current clinical practice guidelines predominantly recommend antibiotic therapy as a non-surgical approach, primarily addressing secondary infections in necrotic areas. However, this mainly addresses the potential infectious complication of MRONJ. Medical approaches including PENT-E, teriparatide, PBM, and PDT can result in successful management and should be considered prior to taking a surgical approach. Combined medical management for both preventing and managing MRONJ holds potential for achieving optimal clinical outcomes and avoiding surgical intervention, requiring further validation through larger studies and controlled trials.

Medication-related osteonecrosis of the jaw (MRONJ): a review of pathogenesis hypothesis and therapy strategies

Medication-related osteonecrosis of the jaw (MRONJ), a severe side effect caused by antiresorptive antiangiogenic medication, particularly bisphosphonates (BPs), has become a challenging disease with serious and profound effects on the physical and mental health of patients. Although it occurs with high frequency and is harmful, the exact mechanism of MRONJ remains unknown, and systematic and targeted approaches are still lacking. Maxillofacial surgeons focus on the etiology of osteonecrosis in the mandible and maxilla as well as the appropriate oral interventions for high-risk patients. Adequate nursing care and pharmacotherapy management are also crucial. This review provides a current overview of the clinicopathologic feature and research of MRONJ caused by BPs, with an emphasis on the potential mechanisms and current therapy and prevention strategies of the disease. We are of the opinion that an in-depth comprehension of the mechanisms underlying MRONJ will facilitate the development of more precise and efficacious therapeutic approaches, resulting in enhanced clinical outcomes for patients.

Geranylgeraniol (GGOH), incorporated into a bone cement pellet promotes osteoclast function and healing in a model of medication-related osteonecrosis of the jaw

Introduction

There is no cause -based treatment for Medication-Related Osteonecrosis of the Jaw (MRONJ). MRONJ is a morbid condition including exposed, infected bone and mandibular fractures in osteoporotic individuals and metastatic cancers patients treated with nitrogen containing bisphosphonates (NBP). NBPs inhibit farnesyl diphosphate synthase (FDPS) in the mevalonate pathway, depriving osteoclasts and other bone cells of small GTPases necessary for their function and survival. We test the hypothesis that geranylgeraniol (GGOH),a metabolite downstream of FDPS, when incorporated into a bone cement pellet, enhances osteoclast function and promotes local bone healing in in vitro and in a proven animal model of MRONJ.

Methods

3H labelled GGOH (2 mM) was incorporated into a Hydroset bone cement pellet and release from the cement was assessed over time. To assess the effect on bone cell function, the GGOH-loaded cement was placed in a porous filter above cultured osteoclasts treated with bisphosphonate and the effect on osteoclast survival and function were measured. In a pilot study the effect of GGOH on osteotomy microstructure was measured in a rat model of MRONJ using a split mouth design.

Results

The release of GGOH from bone cement increased osteoclast survival/metabolic activity, and promoted resorption of the calcified substrate. In vivo released GGOH limited the effects of the bisphosphonate and promoted healing. In an animal pilot study, GGOH from the infused cement carrier stabilizes bone structure and restores the ability of osteoclasts to remodel.

Conclusion

These initial findings point to GGOH in a bone cement carrier as a useful therapeutic approach to prevent or mitigate the pathogenesis of MRONJ.

Treatment of Medication-Related Osteonecrosis of the Jaw: Controversies in Causality and Therapy

Medication-related osteonecrosis of the jaw (MRONJ) is a most interesting, complex and "elusive" condition seen by the oral health care provider. It is plagued by controversy and although a wealth of research has created clinical treatment databases, there is no "gold standard" algorithm to be applied in a universal fashion. The purpose of this article is to explore several controversies associated with the etiology(s), staging, treatments, and long-term resolution of MRONJ in patients who are treated by the oral health care provider. Controversies for optimizing prevention, and disease control will also be discussed from an interdisciplinary perspective.

Awareness of Medication-Related Osteonecrosis of the Jaws Amongst Patients on Antiresorptive and Antiangiogenic Medications

Background Medication-related osteonecrosis of the jaws (MRONJ) is a rare but severe condition that has garnered increasing attention in recent years. It primarily affects individuals undergoing treatment with antiresorptive and antiangiogenic medications, such as bisphosphonates and denosumab, commonly prescribed for osteoporosis and cancer-related bone metastases. Therefore, the present study aimed to assess awareness and understanding of MRONJ among patients receiving antiresorptive and antiangiogenic medications. Methods A cross-sectional survey was conducted among 110 patients receiving antiresorptive and antiangiogenic medications in a clinical setting. Participants were given a structured questionnaire to assess their awareness of MRONJ. The questionnaire covered aspects such as MRONJ, bisphosphonate usage, and awareness of the condition's potential complications. Demographic information was also collected. Chi-square and Fisher's tests were performed using SPSS statistical software. Results In terms of gender distribution, 63.6% of the participants were female. Concerning age distribution, the majority (43.6%) fell within the 21 to 40 age group, whereas only 5.5% were aged over 60. Regarding educational attainment, a substantial majority (58.2%) of the participants held a bachelor's degree. The study findings reveal that a considerable proportion (35.5%) of participants possess awareness regarding jaw osteonecrosis, and this association is statistically significant (p=0.002). A substantial number of participants administered the medication orally (30.9%), while others utilized various administration routes, including injection (IV and others) (40%), and this difference was also statistically significant (p=0.001). Most participants took bisphosphonates for osteoporosis (41.8%) or cancer (13.6%), both statistically significant (p<0.01). Gender had no significant impact (p>0.01), but age showed potential associations (p=0.07 for awareness, p=0.003 for medication use). Educational backgrounds had no significant link, except for bisphosphonate usage (p<0.01) and side effects reporting (p<0.01). Conclusion Notably, a small percentage of participants demonstrated awareness of this condition, indicating a need for continued education and awareness campaigns. Further research and interventions may be warranted to address the specific needs of different age groups and educational backgrounds in promoting safe and effective medication management.

Rat Calvaria Model Mimicking the Intraoral Lesion of Medication-Related Osteonecrosis in the Jaw: A Preliminary Test

Numerous preclinical intraoral models have been proposed to study medication-related osteonecrosis of the jaws (MRONJ). However, an extraoral animal model is necessary to investigate the effects of interventions such as grafts or direct therapeutics. This study aimed to establish a MRONJ rat model on the calvaria. Seven rats were allocated to either the control or MRONJ group. The MRONJ group received injections of zoledronic acid and dexamethasone to induce osteonecrosis over 4 weeks. Two weeks after these injections, the maxillary first molar was extracted, and two calvaria defects were created using a 4 mm trephine burr. One defect was left untreated, while the other was filled with harvested calvaria bone. A histological examination of all calvaria in the MRONJ group revealed avascular necrosis and the destruction of cortical bone. An independent t-test and Pearson's correlation coefficient were used for statistical analysis and the evaluation of alveolar and calvaria defects. The total alveolar and calvaria defect volume in the control group was significantly smaller than that in the MRONJ group. A statistically significant correlation was observed between alveolar and calvaria defects (Pearson correlation = 0.6, p = 0.023). The autogenous grafts showed poor results in the MRONJ group since they failed to revascularize and exhibited necrosis. The calvaria in this study successfully mimicked MRONJ lesions with avascular necrosis. This preclinical model could be used to develop treatments that are applicable to MRONJ.

Correlations between Immune Response and Etiopathogenic Factors of Medication-Related Osteonecrosis of the Jaw in Cancer Patients Treated with Zoledronic Acid

Impairment of the immune response in MRONJ (medication-related osteonecrosis of the jaws) is one of the still unclear etiopathogenic mechanisms of this condition encountered in cancer patients treated with bisphosphonates, with negative effects on the patient's quality of life. The aim of the present study was to correlate the immune response with etiopathogenic factors via immunohistochemical evaluation of the maxillary tissues in zoledronic acid osteonecrosis. The retrospective study included a group of 51 patients with various types of cancers, diagnosed with stage 2 or 3 MRONJ at zoledronic acid and treated surgically. Immunohistochemical expressions of αSMA, CD3, CD4, CD8, CD20, CD79α, CD68, CD204, and tryptase were evaluated. Immunohistochemical markers expressions were statistically analyzed according to the duration of the treatment, the trigger factor, the location of the MRONJ, and the healing status. Analysis of the immune response included T lymphocytes, B lymphocytes, plasma cells, macrophages, and mast cells. The duration of treatment significantly influenced the immunohistochemical expression of most markers (p < 0.05). For an increasing trend in treatment duration, a decreasing trend in marker score was observed, suggesting an inverse correlation. The expression of the markers was different depending on the trigger factor, on MRONJ localization (maxilla/mandible), and the healing status, being more intense in patients cured per primam compared to those who had relapses. The patient's immune response was negatively influenced by the duration of the treatment, the trigger factor, the location of the lesion in the mandible, and the recurrence of MRONJ.

[The recombinant human parathyroid hormone, teriparatide as an alternative remedy for the medication-related osteonecrosis of the jaw]

In developed countries, osteoporosis is one of the most common debilitating conditions in the population over the age of 50. Unfortunately, the pathomechanism of the disease is still not fully understood. Nowadays, the administration of antiresorptive drugs blocking osteoclastic activity is the most commonly used medication to slow down the speed of the bone loss. One of the uncommon side effects of such drugs is the medication-related osteonecrosis of the jaw (MRONJ). Recently, a number of alternative therapeutic approaches has been tested and published, amongst them the recombinant human parathyroid hormone (rhPTH, teriparatide) use, which is turning into a promising treatment modality. According to certain meta-analyses, its pharmacological effect on increasing bone mineral density and controlling pathological vertebral fractures is superior to antiresorptive drugs; however, the so-called "off-label" application of teriparatide remains controversial. As intermittent administration of teriparatide stimulates bone formation, several animal and clinical studies indicated that systemic application of teriparatide shortened fracture healing time and improved quality of the callus and the newly formed bone. Furthermore, recently several clinical studies showed the beneficial effect of the intermittent rhPTH administration in the management of MRONJ. This article reviews the history of the anabolic effect of the low-dose rhPTH discovery, provides evidence-based data from animal and human studies, summarizes its biological mechanisms and the clinical benefits of the anabolic therapy and also their possible role in the management of MRONJ. The majority of the clinical data indicates that, in the case of therapy-resistant osteonecrosis, it may be worthwhile to apply short-term intermittent teriparatide therapy. Notwithstanding, more randomized clinical trials are necessary in order to confirm the efficacy and the safety of the use of teriparatide in the treatment of MRONJ. Orv Hetil. 2023; 164(36): 1406-1415.

Efficacy of fibrin-rich platelets and leukocytes (L-PRF) in tissue repair in surgical oral procedures in patients using zoledronic acid-case-control study

INTRODUCTION

Medication-related osteonecrosis of the jaws (MRONJ) is a complication that develops in patients who use or have used antiresorptive or antiangiogenic medications for the treatment of bone metabolic disease and bone metastases. Clinically, MRONJ is characterized by the appearance of an inflammation in soft tissues and exposure of necrotic bone tissue in mandible or maxilla, for a period of 8 weeks, in patients with no history of head and neck radiotherapy that were being or are being treated with antiresorptive and/or antiangiogenic agents. The fibrin-rich platelets and leukocytes (L-PRF) membrane has been used as an alternative for MRONJ prevention. The aim of this study was to evaluate the use of L-PRF in prevention and treatment of bone necrosis.

MATERIAL AND METHODS

The patients included had MRONJ diagnosis confirmed after clinical and radiographic examination and patients whose only therapeutic option was dental extraction.

RESULTS

Twenty patients were included in the study and were divided in three groups. Two patients were removed from the study due to previous history of pentoxifylline and tocopherol use. The result of surgical treatment was successful in 57% in group 1 (control/MRONJ prevention), 100% in group 2 (MRONJ prevention), and 80% in group 3 (MRONJ treatment).

CONCLUSION

L-PRF is an autologous biomaterial that allows the release of growth factors for a prolonged time, resulting in a better healing, reducing the risk contamination, edema, and postoperative pain, being a great ally in the prevention and treatment of MRONJ because it returns to these patients, mainly quality of life, reducing pain, and recurrent infections commonly seen in the processes of bone necrosis of the jaws.

Menaquinone-4 prevents medication-related osteonecrosis of the jaw through the SIRT1 signaling-mediated inhibition of cellular metabolic stresses-induced osteoblast apoptosis

Long-term usage of bisphosphonates, especially zoledronic acid (ZA), induces osteogenesis disorders and medication-related osteonecrosis of the jaw (MRONJ) in patients, thereby contributing to the destruction of bone remodeling and the continuous progression of osteonecrosis. Menaquinone-4 (MK-4), a specific vitamin K2 isoform converted by the mevalonate (MVA) pathway in vivo, exerts the promotion of bone formation, whereas ZA administration suppresses this pathway and results in endogenous MK-4 deficiency. However, no study has evaluated whether exogenous MK-4 supplementation can prevent ZA-induced MRONJ. Here we showed that MK-4 pretreatment partially ameliorated mucosal nonunion and bone sequestration among ZA-treated MRONJ mouse models. Moreover, MK-4 promoted bone regeneration and inhibited osteoblast apoptosis in vivo. Consistently, MK-4 downregulated ZA-induced osteoblast apoptosis in MC3T3-E1 cells and suppressed the levels of cellular metabolic stresses, including oxidative stress, endoplasmic reticulum stress, mitochondrial dysfunction, and DNA damage, which were accompanied by elevated sirtuin 1 (SIRT1) expression. Notably, EX527, an inhibitor of the SIRT1 signaling pathway, abolished the inhibitory effects of MK-4 on ZA-induced cell metabolic stresses and osteoblast damage. Combined with experimental evidences from MRONJ mouse models and MC3T3-E1 cells, our findings suggested that MK-4 prevents ZA-induced MRONJ by inhibiting osteoblast apoptosis through suppression of cellular metabolic stresses in a SIRT1-dependent manner. The results provide a novel translational direction for the clinical application of MK-4 for preventing MRONJ.

From Cells to Environment: Exploring the Interplay between Factors Shaping Bone Health and Disease

The skeletal system is an extraordinary structure that serves multiple purposes within the body, including providing support, facilitating movement, and safeguarding vital organs. Moreover, it acts as a reservoir for essential minerals crucial for overall bodily function. The intricate interplay of bone cells plays a critical role in maintaining bone homeostasis, ensuring a delicate balance. However, various factors, both intrinsic and extrinsic, can disrupt this vital physiological process. These factors encompass genetics, aging, dietary and lifestyle choices, the gut microbiome, environmental toxins, and more. They can interfere with bone health through several mechanisms, such as hormonal imbalances, disruptions in bone turnover, direct toxicity to osteoblasts, increased osteoclast activity, immune system aging, impaired inflammatory responses, and disturbances in the gut-bone axis. As a consequence, these disturbances can give rise to a range of bone disorders. The regulation of bone's physiological functions involves an intricate network of continuous processes known as bone remodeling, which is influenced by various intrinsic and extrinsic factors within the organism. However, our understanding of the precise cellular and molecular mechanisms governing the complex interactions between environmental factors and the host elements that affect bone health is still in its nascent stages. In light of this, this comprehensive review aims to explore emerging evidence surrounding bone homeostasis, potential risk factors influencing it, and prospective therapeutic interventions for future management of bone-related disorders.

Sixty-Month Follow Up of Clinical MRONJ Cases Treated with CGF and Piezosurgery

AIMS

Medication-related osteonecrosis of the jaw (MRONJ) is a drug-related adverse reaction characterized by bone destruction and necrosis in the jaw. This case series aims to evaluate the treatment approaches and outcomes in MRONJ patients.

MATERIALS AND METHODS

The retrospective study was conducted at the Dental Unit of the University of Bari, Italy. Patients with MRONJ were treated and followed up for 60 months. The treatment approach involved piezosurgery and concentrated growth factor (CGF). Six clinical cases from this group are described in detail.

RESULTS

None of the patients showed recurrence of necrotic MRONJ lesions during the follow-up period. The surgical interventions, including bone resections and the application of CGF, resulted in successful mucosal healing and the prevention of disease progression.

CONCLUSIONS

This study highlights the complexity of managing MRONJ and the importance of a multidisciplinary approach. Conservative treatment options and minimally invasive surgery have shown efficacy in controlling symptoms and improving patients' quality of life. However, the optimal treatment approach remains a challenge, and further studies are needed to evaluate alternative therapies and resective surgery. A comprehensive preoperative evaluation and collaboration among dental, endocrinology, and oncology specialists are crucial for personalized and multidisciplinary management. Ongoing research efforts are necessary to explore new therapeutic modalities and improve our understanding of MRONJ management, providing better support to patients dealing with this complex condition.

Recurrent submandibular fistula after Sunitinib treatment in a patient with renal cell carcinoma: a case report

Sunitinib is commonly used in the treatment of patients with renal cell carcinoma and is associated with serious side-effects. We present the first report of a recurrent submandibular fistula in a patient treated with sunitinib. A 68-year-old man was referred to our clinic for a cutaneous fistula situated on the right side of his lower jaw. The patient had been diagnosed with bone metastases from a renal carcinoma 2 years ago and had received a single 4 mg dose of zoledronic acid and subsequent treatment with sunitinib 37.5 mg once daily for the past 4 weeks. The patient was treated surgically by a perilesional incision and primary closure with sutures, advised on meticulous oral hygiene and was kept on an antimicrobial agent in the form of clindamycin. After reinitiating his oncological treatment with sunitinib the cutaneous fistula re-appeared and bone abnormalities were also detected on his X-ray. After 18 months a contralateral cutaneous fistula was observed along with a spontaneous avulsion of the patient's left molar. Repeat surgical treatment and sequestrectomy was performed with the subsequent histopathological examination revealing a suspicion of osteonecrosis of the jaw and an associated Actinomyces infection.

Osteonecrosis of the Jaws: An Update and Review of Literature

Aim

To provide a concise review on risk factors, stages, pathophysiology, prevention and possible treatment options for both MRONJ and ORN individually.

Methods

The review was conducted according to the 'Preferred Reporting Items for Systematic Reviews and Meta-Analyses' (PRISMA) guidelines. A comprehensive search of the PUBMED, Ebsco, SCOPUS, WEB OF SCIENCE and NDH for articles published up until 2021 was performed. After screening and full text analyses, 44 studies were included in this review. Definition, risk factors, etiology, symptoms, stages, pathophysiology, prevention and possible management options were explored and highlighted in this article.

Results

Three studies described osteonecrosis of jaw (ONJ) in general, 15 studies described ONJ associated with radiotherapy and 26 studies described ONJ associated with medications. Both the two conditions (ORN) and (MRONJ) have relatively similar clinical presentations clearing the fact that a resemblance in clinical presentations does not necessarily denote a similar pathophysiology.

Conclusion

However, various advancements have been made in the control and management of ONJ, but until and unless need for high tumoricidal doses exists, ONJ will certainly continue to remain as a clinical challenge demanding satisfactory treatment to improve the quality of life of the patient.

The Current Strategy in Hormonal and Non-Hormonal Therapies in Menopause—A Comprehensive Review

Menopause is a natural stage of hormonal aging in women, accompanied by a series of symptoms that reduce the quality of life of a fully active person. As no therapy is entirely satisfactory, the race for a better option is in full swing. Our study objective is to investigate the most recent menopause studies on pharmacological resources, emerging therapies, and the particularities of hormonal replacement therapy (HRT). For this purpose, a comprehensive search was conducted in two main databases (PubMed and Web of Science) guided by the specific keywords “menopause” and “therapy” or “estrogen” or “progesterone” or “hormone replacement” during the last ten years period. Studies were eligible if they met certain criteria: randomized controlled trials (RCT) in adult women with menopause and hormonal or non-hormonal therapies. We selected 62 RCTs, which are focused on four main topics: (a) epidemiology of menopause-related symptoms, (b) hormonal replacement therapy (HRT) selective estrogen receptor modulators, (c) emerging therapies, and (d) menopause. HRT has proven a real health benefit for menopausal women; besides, complementary interventions must be considered. Further studies are needed on menopause and menopause-related therapies. The continuous updating of clinical experience will strengthen the therapeutic benefit and the decision to treat patients safely. This goal will fully access all therapeutic resources to address an unresolved health issue of active adult women.

Medication-Related Osteonecrosis of the Jaws (MRONJ) in Children and Young Patients-A Systematic Review

Medication-related osteonecrosis of the jaw (MRONJ) is defined by the American Association of Oral and Maxillofacial Surgeons (AAOMS) as the presence of an exposed bone area in the maxillofacial region, present for more than eight weeks in patients treated with the use of antiresorptive or antiangiogenic agents, with no history of radiation or metastatic disease. Bisphosphonates (BF) and denosumab (DS) are widely used in adults for the management of patients with cancer and osteoporosis, and recently there has been an increase in their use in child and young patients for the management of disorders such as osteogenesis imperfecta (OI), glucocorticoid-induced osteoporosis, McCune-Albright syndrome (MAS), malignant hypercalcemia, and others. There are differences between case reports in adults compared to child and young patients related to the use of antiresorptive/antiangiogenic drugs and the development of MRONJ. The aim was to analyze the presence of MRONJ in children and young patients, and the relation with oral surgery. A systematic review, following the PRISMA search matrix based on the PICO question, was conducted in PubMed, Embase, ScienceDirect, Cochrane, Google Scholar, and manual search in high-impact journals between 1960 and 2022, publications in English or Spanish, including randomized and non-randomized clinical trials, prospective and retrospective cohort studies, cases and controls studies, and series and case reports. A total of 2792 articles were identified and 29 were included; all of them published between 2007 and 2022, identifying 1192 patients, 39.68% male and 36.24% female, aged 11.56 years old on average, using these drugs mainly for OI (60.15%); 4.21 years on average was the therapy time and 10.18 drug doses administered on average; oral surgery was observed in 216 subjects, reporting 14 cases of MRONJ. We concluded that there is a low presence of MRONJ in the child and youth population treated with antiresorptive drugs. Data collection is weak, and details of therapy are not clear in some cases. Deficiencies in protocols and pharmacological characterization were observed in most of the included articles.

Medication-Related Osteonecrosis of the Jaw: Successful Medical Management of Complex Maxillary Alveolus with Sinus Involvement

Medication-related osteonecrosis of the jaw (MRONJ) in cancer patients presents a considerable challenge in management. Current management is primarily based on interventions in a limited number of cases assessing a single approach. Medical management typically is reported to include antimicrobial therapy with or without surgery. Advances in the understanding of pathogenesis have led to the investigation of additional medical interventions for early-stage necrosis. We present 3 patients with advanced-stage MRONJ of the maxilla using combined medical modalities including antimicrobial therapy, photobiomodulation therapy, pentoxifylline, vitamin E, and synthetic parathyroid hormone. All patients had a good outcome and avoided surgical intervention. We also report biological and functional imaging that may assist in more effective diagnosis and management of MRONJ. The 3 patients reported suggest that combined medical management should be considered in all cases of MRONJ (including stage III) prior to determining if surgical intervention is required. Functional imaging with a technetium bone scan or positron emission tomography scan correlated with diagnosis and confirmed resolution in patients. We present 3 challenging MRONJ patients that were effectively managed with a combined medical and nonsurgical therapy that demonstrated good clinical outcomes avoiding surgical interventions.

Aminobisphosphonates: Reconsideration 25 years after their approval for the treatment of osteoporosis

Aminobisphosphonates are widely used in the treatment of osteoporosis. They have a high affinity for hydroxyapatite, binding primarily to resorbing surfaces, but also to forming surfaces and to some extent to resting surfaces. They inhibit osteoclasts, thereby decreasing remodelling units. Consequently, they increase bone mass and reduce stress risers. This decreases the risk of fractures. If this decrease is sufficient, they can be temporarily withdrawn (drug holidays), which prevents serious complications (atypical femoral fracture). They probably reduce mortality. Virtually all patients with osteoporosis can benefit from them at some point in the course of their disease (at the beginning of treatment or after the administration of anabolics, selective estrogen receptor modulators or denosumab). If well tolerated orally, alendronate and risedronate are preferable. Otherwise, zoledronate is preferred. Their efficacy vs. cost-safety-convenience ratio makes aminobisphosphonates reference drugs in the field of osteoporosis.

In vitro Effect of Geranylgeraniol (GGOH) on Bisphosphonate-Induced Cytotoxicity of Oral Mucosa Cells

Medication-related osteonecrosis of the jaw (MRONJ) is an often-severe complication found in patients receiving bisphosphonates in the management of Paget's, osteoporosis and metastatic bone cancer. Mucosal breakdown with bone exposure is a primary clinical presentation of MRONJ linked to the inhibitory effect of nitrogen-containing bisphosphonates (N-BP) on the mevalonate pathway. Geranylgeraniol (GGOH) has demonstrated a rescue effect on N-BP-treated osteoclasts but the biological effects on oral soft tissues and cells remain unclear. This study aimed to determine whether GGOH could prevent bisphosphonate induced toxicity to oral mucosa cells in vitro. Primary oral fibroblasts and keratinocytes were exposed to different GGOH concentrations or GGOH in combination with two nitrogen-containing bisphosphonates, zoledronic acid (ZA) or pamidronic acid (PA), for 72 h. The metabolic activity of each cell type was measured using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. GGOH without bisphosphonates significantly reduced the metabolic activity of oral mucosa cells. Fibroblasts treated with GGOH and ZA in combination showed a slight increase in metabolic status compared to fibroblasts treated with ZA alone, however this positive effect was not observed in keratinocytes. In the presence of PA, GGOH was unable to increase the metabolic activity of either cell type. These findings demonstrate that GGOH is toxic to oral mucosa cells and that GGOH was not able to prevent bisphosphonate induced toxicity. These data show that GGOH does not have therapeutic potential for bisphosphonate-induced soft tissue toxicity in MRONJ and the use of GGOH as an MRONJ treatment should be strongly reconsidered.

Current Trends in Adjuvant Therapies for Medication-Related Osteonecrosis of the Jaw

Medication-related osteonecrosis of the jaw (MRONJ) is a refractory disease, and a standard protocol for its treatment has not yet been established. In addition, owing to the old age of MRONJ patients and various complications, treatment goals focus on relieving the symptoms and improving the quality of life. For this reason, different treatments such as conservative, surgical, and adjunctive treatments have been attempted. In particular, adjunctive treatment, which is effective for promoting healing and reducing recurrence, is gaining increasing interest, and several studies and clinical trials related to it have been published. Representative adjuvant therapies include teriparatide, recombinant human bone morphogenetic protein-2, hyperbaric oxygen, photobiomodulation and platelet concentrates. All have generally shown beneficial effects; however, no standard protocol for adjunctive treatment exists. Therefore, in this literature review, we briefly summarized the different adjuvant therapies and reviewed clinical reports to help decide whether to use adjuvant therapies in treating patients with MRONJ.

Medication-related osteonecrosis of the jaw: knowledge and perceptions of medical professionals on the usage of bone modifying agents and dental referrals

Bone modifying agents (BMA) like bisphosphonates, antiangiogenic, and antiresorptive agents are widely used to manage bone diseases and cancer. Medication-related osteonecrosis of the jaw (MRONJ) is a potentially serious complication seen in patients on BMA therapy. Dental infection is one of the primary risk factors for MRONJ manifestation; hence its complete removal before initiation of BMA is significant. This can be achieved when a medical professional understands MRONJ and its risk factors and implements timely and regular dental referrals. This multicentre study was performed to assess the knowledge about MRONJ and awareness about the implementation of dental referrals among medical professionals. A custom-designed questionnaire tool was designed and validated by a pilot study. 450 practitioners from 6 medical schools and private practitioners in and around the district were surveyed. The results were analyzed using descriptive statistics. 63.5% (n=80) of the respondents prescribed bisphosphonates at a frequency of 0–5 times in a month. However, 62% (n=78) of the practitioners could correctly indicate the most appropriate definition of MRONJ. Only 49.2% (n=62) of them considered dental consultation mandatory. 73% (n=92) of the practitioners were unaware of management guidelines. There exists a significant gap in the knowledge-based applications in the management of MRONJ. Lack of referrals to dentists before BMA therapy can be a pivotal factor in patient morbidity. Practitioners prescribing BMA should advise patients about regular dental visits and monitor for symptoms of MRONJ.

Osteonecrosis development by tooth extraction in zoledronate treated mice is inhibited by active vitamin D analogues, anti-inflammatory agents or antibiotics

Invasive dental treatment such as tooth extraction following treatment with strong anti-bone resorptive agents, including bisphosphonates and denosumab, reportedly promotes osteonecrosis of the jaw (ONJ) at the extraction site, but strategies to prevent ONJ remain unclear. Here we show that in mice, administration of either active vitamin D analogues, antibiotics or anti-inflammatory agents can prevent ONJ development induced by tooth extraction during treatment with the bisphosphonate zoledronate. Specifically, tooth extraction during treatment with zoledronate induced osteonecrosis in mice, but administration of either 1,25(OH)2D3 or ED71, both active vitamin D analogues, significantly antagonized osteonecrosis development, even under continuous zoledronate treatment. 1,25(OH)2D3 or ED71 administration also significantly inhibited osteocyte apoptosis induced by tooth extraction and bisphosphonate treatment. Administration of either active vitamin D analogue significantly inhibited elevation of serum inflammatory cytokine levels in mice in response to injection of lipopolysaccharide, an infection mimetic. Furthermore, administration of either anti-inflammatory or antibiotic reagents significantly blocked ONJ development following tooth extraction and zoledronate treatment. These findings suggest that administration of active vitamin D, anti-inflammatory agents or antibiotics could prevent ONJ development induced by tooth extraction in patients treated with zoledronate.

Suppression of Bone Necrosis around Tooth Extraction Socket in a MRONJ-like Mouse Model by E-rhBMP-2 Containing Artificial Bone Graft Administration

Medication-related osteonecrosis of the jaw (MRONJ) is related to impaired bone healing conditions in the maxillomandibular bone region as a complication of bisphosphonate intake. Although there are several hypotheses for the onset of MRONJ symptoms, one of the possible causes is the inhibition of bone turnover and blood supply leading to bone necrosis. The optimal treatment strategy for MRONJ has not been established either. BMP-2, a member of the TGF-β superfamily, is well known for regulating bone remodeling and homeostasis prenatally and postnatally. Therefore, the objectives of this study were to evaluate whether cyclophosphamide/zoledronate (CY/ZA) induces necrosis of the bone surrounding the tooth extraction socket, and to examine the therapeutic potential of BMP-2 in combination with the hard osteoinductive biomaterial, β-tricalcium phosphate (β-TCP), in the prevention and treatment of alveolar bone loss around the tooth extraction socket in MRONJ-like mice models. First, CY/ZA was intraperitoneally administered for three weeks, and alveolar bone necrosis was evaluated before and after tooth extraction. Next, the effect of BMP-2/β-TCP was investigated in both MRONJ-like prevention and treatment models. In the prevention model, CY/ZA was continuously administered for four weeks after BMP-2/β-TCP transplantation. In the treatment model, CY/ZA administration was suspended after transplantation of BMP-2/β-TCP. The results showed that CY/ZA induced a significant decrease in the number of empty lacunae, a sign of bone necrosis, in the alveolar bone around the tooth extraction socket after tooth extraction. Histological analysis showed a significant decrease in the necrotic alveolar bone around tooth extraction sockets in the BMP-2/β-TCP transplantation group compared to the non-transplanted control group in both MRONJ-like prevention and treatment models. However, bone mineral density, determined by micro-CT analysis, was significantly higher in the BMP-2/β-TCP transplanted group than in the control group in the prevention model only. These results clarified that alveolar bone necrosis around tooth extraction sockets can be induced after surgical intervention under CY/ZA administration. In addition, transplantation of BMP-2/β-TCP reduced the necrotic alveolar bone around the tooth extraction socket. Therefore, a combination of BMP-2/β-TCP could be an alternative approach for both prevention and treatment of MRONJ-like symptoms.

Medication-Related Osteonecrosis of the Jaw: A Critical Narrative Review

Background: Nearly two decades have passed since a paradoxical reaction in the orofacial region to some bone modifying agents and other drugs was recognized, namely medication-related osteonecrosis of the jaw (MRONJ). Purpose: The aim of this manuscript was to critically review published data on MRONJ to provide an update on key terminology, concepts, and current trends in terms of prevention and diagnosis. In addition, our objective was to examine and evaluate the therapeutic options available for MRONJ. Methods: The authors perused the most relevant literature relating to MRONJ through a search in textbooks and published articles included in several databases for the years 2003–2021. Results and conclusions: A comprehensive update of the current understanding of these matters was elaborated, addressing these topics and identifying relevant gaps of knowledge. This review describes our updated view of the previous thematic blocks, highlights our current clinical directions, and emphasizes controversial aspects and barriers that may lead to extending the accumulating body of evidence related to this severe treatment sequela.