Medication-related osteonecrosis of the jaw: A literature review

Pathogenesis and multidisciplinary management of medication-related osteonecrosis of the jaw

Medication-related osteonecrosis of the jaw (MRONJ) is a serious side effect of bone-modifying agents and inhibits angiogenesis agents. Although the pathogenesis of MRONJ is not entirely clear, multiple factors may be involved in specific microenvironments. The TGF-β1 signalling pathway may have a key role in the development of MRONJ. According to the clinical stage, multiple variables should be considered when selecting the most appropriate treatment. Therefore, the prevention and management of treatment of MRONJ should be conducted in patient-centred multidisciplinary team collaborative networks with oncologists, dentists and dental specialists. This would comprise a closed responsibility treatment loop with all benefits directed to the patient. Thus, in the present review, we aimed to summarise the pathogenesis, risk factors, imaging features, clinical staging, therapeutic methods, prevention and treatment strategies associated with MRONJ, which may provide a reference that can inform preventive strategies and improve the quality of life for patients in the future.

Osteonecrosis of the jaw associated with imatinib therapy in myeloproliferative neoplasm: a rare case report

Medication-related osteonecrosis of the jaw (MRONJ) is a relatively infrequent but very well-known adverse effect of bisphosphonates. This rare complication of bisphosphonates is rarest with the use of certain drugs. Tyrosine kinase inhibitors (TKIs), particularly used in renal cell carcinoma or gastrointestinal tumors as a chemotherapeutic agent, can precipitate this particular medical condition of bone when it is associated with either radiation or bisphosphonates, though, monodrug therapy with TKIs rarely causes MRONJ. This article describes a rare case of necrosis of the jawbone in a patient with a myeloproliferative neoplasm who was receiving the TKI imatinib and had no history of bisphosphonate or radiation therapy to head and neck region.

Osteonecrosis of the jaws associated with protein kinase inhibitors: a systematic review

This systematic review analysed evidence relating to medication-related osteonecrosis of the jaws (MRONJ) associated with protein kinase inhibitors in antiresorptive naïve patients. A literature search of major biomedical databases was conducted in March 2020. Information extracted from relevant articles included bibliographic information, patient characteristics, MRONJ characteristics at diagnosis, management strategies and outcomes. Sixteen studies, representing data from 17 patients, were included for final analysis. Descriptive statistics were used to synthesis available data. Eleven protein kinase inhibitors were implicated, with a mean exposure of 13 months prior to MRONJ. Renal cell carcinoma was the primary diagnosis in 41.2% of patients. Patient symptoms, clinical features, radiographic findings and histological findings were consistent with those previously described in patients with MRONJ associated with antiresorptive medications. Overall, there was a 75% rate of cure, with a mean healing time of 17.2 weeks. Patients were treated surgically in 53.3% of the cases. Patients treated surgically achieved complete healing in 100% of cases, compared with 58% in those treated conservatively. Drug discontinuation was reported in 69.2% of patients. Patients who had the offending drug discontinued achieved complete healing in 75% of cases, compared with 50% in those who did not. Evidence relating to MRONJ associated with protein kinase inhibitors is of low quality. From the available data, there are notable differences relating to patient characteristics, treatment strategies and outcomes, between MRONJ associated with protein kinase inhibitors compared with antiresorptives. Higher quality evidence is required to support the findings of this review.

Tetrahedral Framework Nucleic Acid Promotes the Treatment of Bisphosphonate-Related Osteonecrosis of the Jaws by Promoting Angiogenesis and M2 Polarization

Bisphosphonates are often used to treat osteoporosis, malignant bone metastases, and hypercalcemia. However, it can cause serious adverse reactions, bisphosphonate-related osteonecrosis of the jaw (BRONJ), which seriously affects the quality of life of patients. At present, the treatment of BRONJ is still difficult to reach an agreement, and there is no effective treatment. Therefore, it is very important to find effective treatments. Many studies have shown that the occurrence of BRONJ may be due to unbalanced bone turnover, anti-angiogenesis, bacterial infection, direct tissue toxicity, and abnormal immune function. The previous research results show that tetrahedral framework nucleic acids (tFNAs), a new type of nanomaterial, can promote various biological activities of cells, such as cell proliferation, migration, anti-inflammation and anti-oxidation, and angiogenesis. Therefore, we intend to explore the potential of tFNAs in the treatment of BRONJ through this study. The results show that tFNAs can promote the treatment of BRONJ by promoting angiogenesis and promoting M2 polarization in macrophages and inhibiting M1 polarization both in vitro and in vivo. These results provide a theoretical basis for the application of tFNAs in the treatment of BRONJ and also provide new ideas and methods for the treatment of other diseases based on ischemia and immune disorders.

BMP-2/β-TCP Local Delivery for Bone Regeneration in MRONJ-Like Mouse Model

Medication-related osteonecrosis of the jaw (MRONJ) is a severe pathological condition associated mainly with the long-term administration of bone resorption inhibitors, which are known to induce suppression of osteoclast activity and bone remodeling. Bone Morphogenetic Protein (BMP)-2 is known to be a strong inducer of bone remodeling, by directly regulating osteoblast differentiation and osteoclast activity. This study aimed to evaluate the effects of BMP-2 adsorbed onto beta-tricalcium phosphate (β-TCP), which is an osteoinductive bioceramic material and allows space retention, on the prevention and treatment of MRONJ in mice. Tooth extraction was performed after 3 weeks of zoledronate (ZA) and cyclophosphamide (CY) administration. For prevention studies, BMP-2/β-TCP was transplanted immediately after tooth extraction, and the mice were administered ZA and CY for an additional 4 weeks. The results showed that while the tooth extraction socket was mainly filled with a sparse tissue in the control group, bone formation was observed at the apex of the tooth extraction socket and was filled with a dense connective tissue rich in cellular components in the BMP-2/β-TCP transplanted group. For treatment studies, BMP-2/β-TCP was transplanted 2 weeks after tooth extraction, and bone formation was followed up for the subsequent 4 weeks under ZA and CY suspension. The results showed that although the tooth extraction socket was mainly filled with soft tissue in the control group, transplantation of BMP-2/β-TCP could significantly accelerate bone formation, as shown by immunohistochemical analysis for osteopontin, and reduce the bone necrosis in tooth extraction sockets. These data suggest that the combination of BMP-2/β-TCP could become a suitable therapy for the management of MRONJ.

Awareness of the risk of developing medication-related osteonecrosis of the jaw among bisphosphonate users

Objective

In this retrospective observational study, we evaluated awareness among patients using bisphosphonates (BPs) regarding the risk of developing medication-related osteonecrosis of the jaw (MRONJ) and whether they received appropriate dental screening and treatment prior to commencing medication.

Methods

Patients using BPs who attended the endodontics clinic at Jordan University Hospital in 2019 were interviewed using a pre-designed questionnaire. Data were analysed using descriptive statistics and chi-squared tests.

Results

In total, 110 patients were interviewed (84 women, 26 men; age 40–78 years). A total of 94 patients were using oral BP and 16 received intravenous (IV) BP. We found that only 12.4% of participants were aware about the risk of MRONJ following BP use, and only one third of them has received information from their prescribing physicians. In total, 5% of participants were referred to a dentist for screening prior to initiating BP treatment. Patients receiving IV BP and those with a university-level education had better awareness about the risk of MRONJ than oral BP users and those with a high school education level.

Conclusion

Patients’ awareness about MRONJ risk was low in our population. Better patient education and collaboration among physicians and dentists are needed prior to starting BP treatment.

Fluorescence-guided surgical management of medication-related osteonecrosis of the jaws

Medication-related osteonecrosis of the jaw (MRONJ) results in progressive destruction of the jawbones, and advanced cases demand surgical intervention. The total removal of necrotic bone is required to prevent recurrence and infection. However, determining the limits between necrotic and healthy bone is a challenge. The use of fluorescence to detect tissue alterations and determine necrosis extension is a promising method to avoid inadequate bone debridement. In the literature, there are several studies and reported cases that successfully use fluorescence-guided surgery (FGS) of MRONJ. The objective of this study was to present a critical review of the literature regarding the intraoperative use of optic fluorescence to differentiate healthy and necrotic bone in MRONJ. Studies that evaluated the intraoperative use of optic fluorescence to determine the surgical margins of MRONJ were searched in Pubmed/Medline and Scopus databases using the following terms: "medication-related osteonecrosis of the jaws" and "fluorescence". Eighteen papers describing the intraoperative use of FGS in ONJ management were selected, totalizing 218 patients. Of those 18 papers, only 5 were prospective studies, and the other 13 were isolated case reports, case series, and technical notes. The use of FGS to delimitate the resection margin of MRONJ is a promising method. There is no need for the application of exogenous fluorophore to perform FGS and the most often used light device was the VELScope® system. Further prospective studies with larger samples are still required to ascertain the fluorescence validity as a supporting method in MRONJ surgical treatment and to establish clinical protocols.

Denosumab-induced osteonecrosis of external auditory canal

Denosumab is the world's first human monoclonal antibody for the treatment of osteoporosis and shares an active pathway with bisphosphonates, strongly suppressing osteoclast activities. This is the first case report describing a possible relationship between the development of osteonecrosis of external auditory canal and denosumab administration. We herein report an 81-year-old woman diagnosed with left osteonecrosis of external auditory canal who had a history of denosumab administration. She underwent left radical mastoidectomy due to being refractory to conservative treatment. No major complications or recurrence were observed in the left ear after surgery, but bone erosion in the right ear has continued to progress slowly despite the cessation of denosumab administration. Otolaryngologists should be aware of the association between osteonecrosis of external auditory canal and denosumab administration and consider performing long-term observation even after cessation.

Osteonecrosis of the jaw induced by arsenic trioxide therapy in a leukemia patient: A rare case report and literature review

A patient suffering from acute promyelocytic leukemia (APL) was referred to the dental department before introduction of chemotherapy by all-trans retinoic acid and arsenic trioxide (ATO). A panoramic radiography showed his third upper maxillary left tooth included into the maxillary bone. The patient presented with a febrile episode. Consequently, the infectious gateway was researched. A left maxillary sinus migration of his third upper left tooth together with a bony sequestrum has been observed on a CT-scan. A surgery was then performed to remove the bony sequestrum and the tooth. The first hypothesis of tooth migration could be that the patient had an infection prior to introduction of chemotherapy. However, neither clinical or radiographic signs were observed during the initial check-up. The second hypothesis is that ATO caused osteonecrosis of the jaw (ONJ) induced the formation of a bony sequestrum associated to the tooth migration into the sinus. ONJ could be a potential adverse of ATO chemotherapy.

Mitigating osteonecrosis of the jaw (ONJ) through preventive dental care and understanding of risk factors

It is well established that alterations in phosphate metabolism have a profound effect on hard and soft tissues of the oral cavity. The present-day clinical form of osteonecrosis of the jaw (ONJ) was preceded by phosphorus necrosis of the jaw, ca. 1860. The subsequent removal of yellow phosphorus from matches in the early 20th century saw a parallel decline in "phossy jaw" until the early 2000s, when similar reports of unusual jaw bone necrosis began to appear in the literature describing jaw necrosis in patients undergoing chemotherapy and concomitant steroid and bisphosphonate treatment. Today, the potential side effect of ONJ associated with medications that block osteoclast activity (antiresorptive) is well known, though the mechanism remains unclear and the management and outcomes are often unsatisfactory. Much of the existing literature has focused on the continuing concerns of appropriate use of bisphosphonates and other antiresorptive medications, the incomplete or underdeveloped research on ONJ, and the use of drugs with anabolic potential for treatment of osteoporosis. While recognizing that ONJ is a rare occurrence and ONJ-associated medications play an important role in fracture risk reduction in osteoporotic patients, evidence to date suggests that health care providers can lower the risk further by dental evaluations and care prior to initiating antiresorptive therapies and by monitoring dental health during and after treatment. This review describes the current clinical management guidelines for ONJ, the critical role of dental-medical management in mitigating risks, and the current understanding of the effects of predominantly osteoclast-modulating drugs on bone homeostasis.

Response of Different Treatment Protocols to Treat Chronic Non-Bacterial Osteomyelitis (CNO) of the Mandible in Adult Patients: A Systematic Review

(1) Background: Chronic non-bacterial osteomyelitis (CNO) is an autoinflammatory bone disease of finally unknown etiology, which can occur alone or related with syndromes (chronic recurrent multifocal osteomyelitis-CRMO; synovitis, acne, pustulosis, hyperostosis and osteitis syndrome-SAPHO). The involvement of the mandible is rather rare. (2) Methods: We carried out a systematic literature search on CNO with mandibular involvement, according to the "Preferred Reporting Items for Systematic Reviews and Meta-Analyses" (PRISMA) guidelines, considering the different synonyms for CNO, with a special focus on therapy. (3) Results: Finally, only four studies could be included. A total of 36 patients were treated in these studies-therefore, at most, only tendencies could be identified. The therapy in the included works was inconsistent. Various therapies could alleviate the symptoms of the disease. A complete remission could only rarely be observed and is also to be viewed against the background of the fluctuating character of the disease. The success of one-off interventions is unlikely overall, and the need for long-term therapies seems to be indicated. Non-steroidal anti-inflammatory drugs (NSAIDs) were not part of any effective therapy. Surgical therapy should not be the first choice. (4) Conclusions: In summary, no evidence-based therapy recommendation can be given today. For the future, systematic clinical trials on therapy for CNO are desirable.

Clinical effects of switching from minodronate to denosumab treatment in patients with postmenopausal osteoporosis: a retrospective study

Background

Denosumab is a major treatment option for patients with postmenopausal osteoporosis; however, the evidence for its use is lacking. Therefore, in this 24-month retrospective study, we aimed to evaluate the effects of switching from minodronate (MIN) to denosumab in these patients.

Methods

Patients with postmenopausal osteoporosis either switched from MIN to denosumab (Group 1; n = 32) or continued MIN treatment (Group 2; n = 24). Bone mineral density (BMD) of the lumbar spine (L2–L4) and femoral neck was assessed at baseline and every 6 months for 24 months. Serum bone-specific alkaline phosphatase (BAP) and N-terminal telopeptide were measured at baseline, 12 months, and 24 months.

Results

Twenty-nine of the 32 patients (90.6%) in group 1 and all patients (24/24) in group 2 completed the 24-month follow-up. Switching from MIN to denosumab (Group 1) significantly increased lumbar BMD at 12, 18, and 24 months (6.1, 7.4, and 9.6%, respectively) and femoral neck BMD at 12, 18, and 24 months (2.8, 3.2, and 3.4%, respectively), whereas MIN continuous treatment (Group 2) showed no significant difference from baseline. Switching therapy also showed a significant decrease in serum BAP from baseline to 12 and 24 months (− 19.3 and − 26.5%, respectively) and serum NTX from baseline to 12 months (− 13.1%), whereas continuous MIN treatment failed to show any significant differences from baseline.

Conclusion

Switching from MIN to denosumab in patients with postmenopausal osteoporosis showed clinical benefits with regard to BMD and bone turnover markers in comparison with continuous MIN treatment. It may therefore be a valid treatment option in the clinical setting.

Oral biosciences: The annual review 2019

BACKGROUND

Journal of Oral Biosciences is devoted to the advancement and dissemination of fundamental knowledge concerning every aspect of oral biosciences.

HIGHLIGHT

This review features review articles in the fields of "Bone Cell Biology," "Microbiology," "Oral Heath," "Biocompatible Materials," "Mouth Neoplasm," and "Biological Evolution" in addition to the review articles by winners of the Lion Dental Research Award ("Role of nicotinic acetylcholine receptors for modulation of microcircuits in the agranular insular cortex" and "Phospholipase C-related catalytically inactive protein: A novel signaling molecule for modulating fat metabolism and energy expenditure") and the Rising Members Award ("Pain mechanism of oral ulcerative mucositis and the therapeutic traditional herbal medicine hangeshashinto," "Mechanisms underlying the induction of regulatory T cells by sublingual immunotherapy," and "Regulation of osteoclast function via Rho-Pkn3-c-Src pathways"), presented by the Japanese Association for Oral Biology.

CONCLUSION

These reviews in the Journal of Oral Biosciences have inspired the readers of the journal to broaden their knowledge regarding various aspects of oral biosciences. The current editorial review introduces these exciting review articles.

Medication-related Osteonecrosis of the Jaw: A Review

Medication-related osteonecrosis of the jaw (MRONJ) is a rare, severe debilitating condition from unknown causes. It is characterized by nonhealing exposed bone in a patient with a history of antiresorptive or antiangiogenic agents in the absence of radiation exposure to the head and neck region. The first case of MRONJ was reported in the early 2000s. Diagnostic criteria for MRONJ was developed by the American Association of Oral and Maxillofacial Surgeons (AAOMS) based on pharmacological history as well as clinical and radiographic features. Antiresorptive medications such as bisphosphonate and denosumab are currently considered the treatment of choice in patients with osteoclastic bone disease. These reduce bone turnover and improve bone density, thereby improving bone quality. These agents have also been shown to reduce the risk of osteoporotic fractures due to their potent effect in suppressing osteoclastic activity by slowing the remodeling process and increasing bone density, thereby improving quality of life for most of the patients. Despite the great benefits of bisphosphonates and other antiresorptive medications, osteonecrosis of the jaw (ONJ) due to the effects of these medications in the presence of a local risk factor is a significant drawback. Moreover, antiangiogenic drugs play a major role in developing bone necrosis. They are prescribed in cancer cases to prevent metastasis through the blood and lymph nodes. These drugs interfere with the formation of new blood vessels, resulting in ischemia and eventually ONJ. This risk can be managed by evaluating the route and the duration of administration as such a risk can be considered dose-time dependent. As a preventive measure, dental screening before initiating any type of ONJ-related medications can significantly lower the risk of ONJ. Treatment goals can be achieved through pain and infection control, in addition to the management of bone necrosis and resorption. The aim of this review is to identify all causative agents and summarize the preventive measures, diagnostic criteria, and treatment strategies related to MRONJ.

Bone Tissue Regeneration in the Oral and Maxillofacial Region: A Review on the Application of Stem Cells and New Strategies to Improve Vascularization

Bone tissue engineering techniques are a promising alternative for the use of autologous bone grafts to reconstruct bone defects in the oral and maxillofacial region. However, for successful bone regeneration, adequate vascularization is a prerequisite. This review presents and discusses the application of stem cells and new strategies to improve vascularization, which may lead to feasible clinical applications. Multiple sources of stem cells have been investigated for bone tissue engineering. The stromal vascular fraction (SVF) of human adipose tissue is considered a promising single source for a heterogeneous population of essential cells with, amongst others, osteogenic and angiogenic potential. Enhanced vascularization of tissue-engineered grafts can be achieved by different mechanisms: vascular ingrowth directed from the surrounding host tissue to the implanted graft, vice versa, or concomitantly. Vascular ingrowth into the implanted graft can be enhanced by (i) optimizing the material properties of scaffolds and (ii) their bioactivation by incorporation of growth factors or cell seeding. Vascular ingrowth directed from the implanted graft towards the host tissue can be achieved by incorporating the graft with either (i) preformed microvascular networks or (ii) microvascular fragments (MF). The latter may have stimulating actions on both vascular ingrowth and outgrowth, since they contain angiogenic stem cells like SVF, as well as vascularized matrix fragments. Both adipose tissue-derived SVF and MF are cell sources with clinical feasibility due to their large quantities that can be harvested and applied in a one-step surgical procedure. During the past years, important advancements of stem cell application and vascularization in bone tissue regeneration have been made. The development of engineered in vitro 3D models mimicking the bone defect environment would facilitate new strategies in bone tissue engineering. Successful clinical application requires innovative future investigations enhancing vascularization.

Synthetic Calcium Phosphate Ceramics as a Potential Treatment for Bisphosphonate-Related Osteonecrosis of the Jaw

(1) Background: Bisphosphonate-related osteonecrosis of the jaw (BRONJ) is one of the most often seen side effects in patients treated with nitrogen-containing bisphosphonates (BPs), a post-surgical non-healing wound condition. Since calcium phosphate (CP) compounds are able to adsorb zoledronate (ZOL) when used as a drug delivery vehicle, we aimed to verify if these ceramics might have a potential protective effect for soft tissues surrounding surgical osseous wounds. (2) Methods: The chemical reaction between ZOL and CP compounds was evaluated through ultraviolet-visible spectroscopy and elemental analysis. A primary culture of human gingival fibroblasts (HGF) was established as a model to evaluate the cytotoxicity of the association of ZOL (5–500 μM) and of ZOL/biphasic calcium phosphates (BCP). Metabolic activity, cell viability, types of cell death, the cell cycle through, and the migration ability of human gingival fibroblasts were evaluated. (3) Results: ZOL was adsorbed by biphasic calcium phosphate compounds in an aqueous solution. The HGF were sensitive to ZOL toxicity; nevertheless, ZOL/BCP showed a significant protective effect regarding metabolic activity, cell viability, and cell migration. (4) Conclusions: BCP interaction with ZOL reduces or abolishes its toxicity in HGF. This finding represents a potential solution for BRONJ in the case of patients undergoing therapy with ZOL.