Bisphosphonate-associated jawbone osteonecrosis: a correlation between imaging techniques and histopathology

Clinical status of established MRONJ in oncology patients continuing bone-modifying agents

The continuation of bone-modifying agents (BMAs) in patients with established medication-related osteonecrosis of the jaw (MRONJ) is a common concern among dentists and oncologists. There is little evidence supporting or refuting the continued use of BMAs or drug holidays and their impact on established MRONJ. This paper evaluates the outcome of continued BMAs use on the patient's MRONJ status. A retrospective review of 29 oncology patients undergoing active cancer care for either metastatic disease or multiple myeloma was conducted. Data on demographics, oncological status, BMA history and MRONJ status were collected. In total, 90% of patients were judged to have healed or stable MRONJ while continuing BMAs. Most patients (69%) continued the same BMA regime (three- or four-weekly) that they were on before developing MRONJ. The average number of BMAs doses received after an MRONJ diagnosis was 12 (range 1-48). Three patients (10.3%) were found to have MRONJ progression, with two patients developing new sites of necrosis. This real-world dataset suggests that the majority of MRONJ cases remain stable and will not worsen with the continuation of BMAs.

Inflammatory Lesions of the Jaws

This article defines the fascial and spatial anatomy of the suprahyoid neck region, delineates the role of CT and MR imaging, discusses the inflammatory conditions of the jaws and adjacent spaces and their clinical symptomatology, and illustrates the appearance of these conditions.

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.

Preoperative Assessment of Medication-Related Osteonecrosis of the Jaw Using [18F]fluoride Positron Emission Tomography (PET)/CT and [18F]fluorodeoxyglucose PET/MRI in Correlation with Histomorphometry and Micro-CT-A Prospective Comparative Study

OBJECTIVES

The purpose of this study was to investigate the imaging characteristics of medication-related osteonecrosis of the jaw (MRONJ) using [18F]fluoride positron emission tomography/computed tomography (PET/CT) and [18F]fluorodeoxyglucose (FDG) PET/magnetic resonance imaging (MRI) for preoperative assessment and to correlate them with microarchitectural and histomorphometric data with respect to clinical findings.

METHODS

Twelve patients (five female; mean age 75 ± 7.6 yr) with symptomatic MRONJ underwent both scans on the same day, and imaging findings were used to plan surgical interventions for seven patients. Bone tracer uptake was classified as high, medium, or low, and surgical samples were evaluated using Micro-CT and histomorphometric analysis.

RESULTS

CT showed medullary sclerosis in all patients, and MRI revealed gadolinium enhancement in four patients. PET imaging revealed remarkably elevated [18F]fluoride uptake and moderately increased [18F]FDG uptake in MRONJ compared to healthy jawbones, with both differences being statistically significant. [18F]fluoride uptake was associated with necrosis, bacteria, and inflammatory tissue. Micro-CT data did not show significant differences, but histomorphometric analysis revealed higher osteocyte and lacunae densities in the high [18F]fluoride uptake group, and more necrotic bone in the medium [18F]fluoride uptake group. Bacteria were observed in all areas.

CONCLUSIONS

In summary, [18F]fluoride PET accurately identified MRONJ extent, revealing functional changes in jawbone remodeling not visible on CT. [18F]FDG PET showed differences in bone and soft tissue, though less pronounced. This method aids in evaluating disease activity and guiding treatment planning, requiring further research for optimal surgical approaches based on tracer uptake.

Novel Histopathological Findings of Micro Bone Fragments and Epithelial Response in the Oral Mucosa in Bisphosphonate-Related Osteonecrosis of the Jaw

Bisphosphonate-related osteonecrosis of the jaw (BRONJ) occurs in the jawbone and interfacing oral mucosa of patients treated with bisphosphonates. Herein, we report novel histopathological findings in the oral mucosa of a surgical specimen obtained from a 61-year-old man with BRONJ. The resected jawbone and adjacent oral mucosa were separated for histological examination. The mucosal tissue was examined using Von Kossa staining and immunohistochemical (CK5/6, p63) staining of non-decalcified paraffin sections. Pseudoepitheliomatous hyperplasia (PEH), a microscopic feature of the mucosal epithelium in BRONJ, was observed in soft tissue specimens, concomitant with inflammatory cell infiltration. Von Kossa staining revealed small fragments of necrotic bone, tens to hundreds of micrometers in size, scattered within the connective tissues; the PEH forefront contacted some of the bone fragments. Immunohistochemical staining demonstrated that occasionally, the PEH not only contacted but also encompassed the bone fragments. To our knowledge, this is the first report of presence of micro bone fragments and their association with PEH in the oral mucosa in BRONJ.

Cooperation between physicians and dentists for osteonecrosis of the jaw: a 2022 Japanese survey

INTRODUCTION

A 2015 survey of the Japan Osteoporosis Society (JOS) on medication-related osteonecrosis of the jaw (MRONJ) revealed that cooperation between physicians and dentists was poor. Discontinuation of antiresorptive agents before tooth extraction was found to increase adverse events without preventing MRONJ. We compared this 2015 survey with a new survey conducted in 2022 to investigate cooperation between physicians and dentists for MRONJ.

MATERIALS AND METHODS

A web-based structured questionnaire including 13 key queries was sent to 3813 physicians who were members of JOS, and 1227 (32.2%) responses were received.

RESULTS

Of the 1227 respondents, 909 (74.1%) had complied with a discontinuation request from a dentist before tooth extraction, although 25.4% of medications were not related to the incidence of MRONJ. Of these, 177 respondents reported 252 adverse events including 10 (1.3%) cases of MRONJ. The prevalence of fractures increased from 4.8% in 2015 to 8.2% in 2022. The rates of respondents who requested oral health care by a dentist before antiresorptive agent therapy and reported cooperation between physicians and dentists were 72.7% and 42.4% in 2022 compared with 32.9% and 24.8% in 2015, respectively. The rates of cooperation among the 47 prefectures in Japan were significantly different, ranging from 10.0 to 83.3% (p = 0.02).

CONCLUSION

This study confirmed increased cooperation between physicians and dentists for MRONJ in Japan. However, a more equal distribution of cooperation across Japan is necessary to optimally manage MRONJ. Discontinuation of antiresorptive agents is no longer necessary because fractures during discontinuation continue to increase in Japan.

Reliability of early stage symptoms/clinical findings of osteonecrosis of the jaw: Japanese Osteoporosis Intervention Trial-05 (JOINT-05)

INTRODUCTION

To investigate the differences in the incidence rates of suspected stage 0/1 osteonecrosis of the jaw (ONJ) and incidence risk of relevant clinical findings of suspected stage 0 ONJ between patients treated with sequential therapy comprising weekly teriparatide for 72 weeks followed by alendronate for 48 weeks vs. those who received monotherapy with alendronate for 120 weeks.

MATERIALS AND METHODS

Suspected stage 0/1 ONJ was defined by non-specific symptoms. Tooth mobility and periodontal symptoms (gingival bleeding, swelling, and/or pain) were selected as clinical findings of suspected stage 0 ONJ. Poisson regression models were applied to calculate the incidence rate ratios of suspected stage 0/1 between the teriparatide group (TG) and alendronate group (AG). Generalized linear models were used to calculate the risk ratios of clinical findings between groups.

RESULTS

Two hundred and sixty-one participants in the TG and 344 in the AG answered a structured questionnaire on oral health and were included in this study. There were no significant differences between the groups in the incidence rate of suspected stage 0/1 ONJ at both 72 and 120 weeks. The risk ratio of the TG to AG for tooth mobility was 0.34 (95% confidence interval [CI] 0.13-0.88, p = 0.02) at 72 weeks and 0.90 (95% CI 0.40-2.03, p = 0.83) at 120 weeks. The incidence rate of tooth mobility related to periodontal symptoms decreased in the TG and increased in the AG during the study.

CONCLUSION

Tooth mobility accompanied by clinical periodontal symptoms may be a useful early sign of stage 0 ONJ.

Medication-Related Osteonecrosis of the Jaws: A Comparison of SICMF-SIPMO and AAOMS Guidelines

(1) Background: Medication-related osteonecrosis of the jaws (MRONJ) is an adverse drug reaction characterized by progressive bone disruption and necrosis in the mandibular and/or maxillary bones. It occurs in individuals who have received antiresorptive drugs without prior radiotherapy. Since its first reported cases in the USA in 2003, extensive literature has emerged worldwide, leading to significant advancements in understanding MRONJ's pathogenesis and management. (2) Results: This article aims to compare the current national recommendations provided by the Italian Society of Maxillofacial Surgery (SICMF)/Italian Society of Oral Pathology and Medicine (SIPMO) and the American Association of Oral and Maxillofacial Surgeons (AAOMS). (3) Conclusions: Historically, the AAOMS advocated for a more conservative approach compared to the Italian guidelines. However, in their 2022 update, the AAOMS adopted a different perspective based on reported evidence, highlighting the advantages of early surgical treatment. Despite resolving some initial controversies, differences still exist between the two sets of recommendations, particularly regarding diagnosis and staging.

Comparison of Different Antibiotic Regimes for Preventive Tooth Extractions in Patients with Antiresorptive Intake-A Retrospective Cohort Study

In the present study, the impacts on success rates between three different antibiotic regimes in patients receiving preventive tooth extraction during/after antiresorptive treatment were compared. For the retrospective analysis, we enrolled patients who had undergone tooth extraction from 2009 to 2019 according to the specified preventive conditions under antiresorptive therapy. Three antibiotic regimens were distinguished: (Group 1) intravenous for 7 days, (Group 2) oral for 14 days, and (Group 3) oral for 7 days of application. The primary endpoint was the occurrence of medication-related osteonecrosis of the jaw at 12 weeks after surgery. A total of 760 patients and 1143 extraction regions were evaluated (Group 1 n = 719; Group 2 n = 126; Group 3 n = 298). The primary endpoint showed no significant difference in the development of medication-related osteonecrosis of the jaw between the groups studied (Group 1 n = 50/669 (7%); Group 2 n = 9/117 (7%); Group 3 n = 17/281 (6%); p = 0.746). Overall, the success rate was 93% after intervention when preventive measures were followed. With the same success rate, a reduced, oral administration of antibiotics seems to be sufficient regarding the possible spectrum of side effects, the development of resistance and the health economic point of view.

Clinical and Histopathological Aspects of MRONJ in Cancer Patients

Medication-related osteonecrosis of the jaw (MRONJ) is a major complication of bisphosphonate treatment in cancer patients, and its etiology is not completely clarified. The study's goal is to find connections between the clinical and histopathological characteristics of osteonecrosis and bisphosphonates in a cohort of cancer patients who had osteonecrosis treated surgically. The retrospective study includes 51 patients of both sexes, aged 46 to 85 years, who underwent surgical treatment for MRONJ in two oral and maxillofacial surgery clinics (Craiova and Constanța). Demographic, clinical, and imaging data from the records of patients with osteonecrosis were analyzed. The surgical treatment removed the necrotic bone, and the harvested fragments were analyzed from a histopathological perspective. The histopathological examination data were evaluated and statistically processed to look for viable bone, granulation tissue, bacterial colonies, and inflammatory infiltrate. In the study groups, MRONJ was found particularly in the posterior regions of the mandible. Tooth extraction, but also periapical or periodontal infections, represented the trigger factors in most of the cases. The surgical therapy consisted of sequestrectomy or bone resection, and the histopathological examination of the fragments revealed osteonecrosis-specific features, such as the lack of bone cells, the development of an inflammatory infiltrate, and the existence of bacterial colonies. MRONJ in cancer patients receiving zoledronic acid is a severe complication that significantly lowers quality of life. Since these patients are not usually monitored by the dentist, they are identified in advanced stages of MRONJ. For these patients, thorough dental monitoring could reduce the incidence of osteonecrosis and its related complications.

Dietary nitrate improves jaw bone remodelling in zoledronate-treated mice

Bisphosphonate-related osteonecrosis of the jaw (BRONJ) is a serious complication that occurs in patients with osteoporosis or metastatic bone cancer treated with bisphosphonate. There is still no effective treatment and prevention strategy for BRONJ. Inorganic nitrate, which is abundant in green vegetables, has been reported to be protective in multiple diseases. To investigate the effects of dietary nitrate on BRONJ-like lesions in mice, we utilized a well-established mouse BRONJ model, in which tooth extraction was performed. Specifically, 4 mM sodium nitrate was administered in advance through drinking water to assess the short- and long-term effects on BRONJ. Zoledronate injection could induce severe healing inhibition of the tooth extraction socket, while addition of pretreating dietary nitrate could alleviate the inhibition by reducing monocyte necrosis and inflammatory cytokines production. Mechanistically, nitrate intake increased plasma nitric oxide levels, which attenuated necroptosis of monocytes by downregulating lipid and lipid-like molecule metabolism via a RIPK3 dependent pathway. Our findings revealed that dietary nitrate could inhibit monocyte necroptosis in BRONJ, regulate the bone immune microenvironment and promote bone remodelling after injury. This study contributes to the understanding of the immunopathogenesis of zoledronate and supports the feasibility of dietary nitrate for the clinical prevention of BRONJ.

Quantitative indices for cone-beam CT assessment of Medication-Related Osteonecrosis of the Jaw - a scoping review

Objectives

It is not unusual for Medication-related osteonecrosis of the jaw (MRONJ) lesions that have similar clinical presentation and staging to have dissimilar radiographic extent of disease. The aim of this review was to explore the published scientific literature for quantitative indices that describe the cone-beam computerized tomography (CBCT) radiographic features of MRONJ lesions and assess their clinical utility.

Method and Materials

A scoping review of the literature was performed to identify quantitative indices developed to describe the CBCT radiographic features of MRONJ lesions. Five electronic databases were included in the review: PubMed, Scopus, Web of Science, Trip medical database, and Cochrane Library. Articles published from the year 2003 onward were included in the review.

Results

367 articles were initially included in the review. 39 abstracts were screened for full-text assessment. The scoping review yielded 12 full length articles with169 cases reported. The Composite Radiographic Index score (CRI score) was identified as the most meaningful index in published literature that attempted to quantify qualitative radiographic changes (Walton, Grogan et al. 2019). However, lesions with similar CRI scores that corresponded to intermediate severity (3-5) may be very dissimilar radiographically in both nature and extent of radiographic changes, undercutting its clinical value.

Conclusion

The CRI index score was the only relevant index for cross-sectional (one-time) assessment of established MRONJ lesions (non-stage 0). This scoping review yielded several critical questions regarding the clinical significance and prognostic implications of various radiographic changes in MRONJ, thereby identifying focus areas for future research.

Evaluation of Medication-Related Osteonecrosis of the Jaw (MRONJ) in Terms of Staging and Treatment Strategies by Dental Students at Different Educational Levels

Background: The role of medication-related osteonecrosis of the jaw (MRONJ) as a dento-maxillo-facial pathology is becoming increasingly important due to its growing prevalence. The success of preventive and therapeutic measures relies mainly on the dentist's ability to correctly diagnose the disease. Methods: The aim of this study was to evaluate the skills of dental students of different educational levels in choosing the correct stage, diagnostics, and treatment option for MRONJ based on clinical and radiographic imaging (panoramic radiograph, CBCT). The study was designed as a cross-sectional cohort study. Twenty dental students were asked to complete a questionnaire in their third and fifth year of studies in which they had to correctly stage the disease, choose the radiological diagnostics and recommend the treatment. The control group contained experienced oral and maxillofacial surgeons. Results: With an overall performance of 59% (third year: 145.2/248 points; fifth year: 145.3/248 points), no statistically significant difference between the educational levels could be observed. The classification based on CBCT imaging was significantly more often correct compared to panoramic radiographs (p < 0.001). Conclusions: This study highlights students' lack of knowledge in staging, diagnostics, and treatment of MRONJ, even though the CBCT positively affected decision-making. No significant increase in knowledge could be confirmed through clinical education. This study highlights the need for students to catch up on MRONJ diagnostics and treatment planning. Further expansion of teaching in this disease's context and X-ray diagnostics is needed.

Lansoprazole and zoledronate delays hard tissue healing of tooth extraction sockets in dexamethasone-treated mice

Proton pump inhibitors (PPIs) are among the most commonly prescribed medicines for the management of acid-related gastrointestinal diseases. Osteonecrosis of the jaw (ONJ) is a serious adverse event that is associated with the use of antiresorptive and antiangiogenic agents. According to previous clinical reports, the use of PPIs contributes to the pathogenesis of severe ONJ that requires surgery. Here, we investigated the effects of lansoprazole (LP) or LP in combination with zoledronate (ZOL) on ONJ development in mice. C57BL/6J mice were administered ZOL (125 μg/kg intravenously, twice weekly) and/or LP (10 mg/kg intraperitoneally; 3 weeks of 3 consecutive days followed by 1 day off). One week after initiation of the study, the first molar was atraumatically extracted. Concurrently with ZOL administration, dexamethasone (Dex) was administered (5 mg/kg intraperitoneally, twice weekly). Micro-computed tomography and histological evaluation were performed to characterize femoral structures, tooth extraction sockets, and osteonecrosis areas. The results showed that ZOL/Dex significantly increased bone mass compared to saline/Dex, while the simultaneous administration of LP and ZOL/Dex diminished the ZOL-induced enhancement of bone mass. In the alveolar bone around the tooth extraction socket, necrotic bone was significantly increased in the LP/Dex group compared to the saline/Dex group. However, no signs of more severe ONJ-like lesions were observed following combined administration of LP and ZOL/Dex, other than an increase in the number of non-attached TRAP-positive cells. Our findings in a mouse model suggest that LP use can be a risk factor for the development of ONJ.

Correlation of dynamic contrast-enhanced bone perfusion with morphologic ultra-short echo time MR imaging in medication-related osteonecrosis of the jaw

OBJECTIVES

To investigate whether dynamic contrast-enhanced (DCE)-MR bone perfusion could serve as surrogate for morphologic ultra-short echo time (UTE) bone images and to correlate perfusion with morphologic hallmarks in histologically proven foci of medication-related osteonecrosis of the jaw (MRONJ).

METHODS

Retrospective study including 20 patients with established diagnosis of MRONJ. Qualitative consensus assessment of predefined jaw regions by two radiologists was used as reference standard using Likert scale (0-3) for standard imaging hallmarks in MRONJ (osteolysis, sclerosis, periosteal thickening). DCE-MRI measurements performed in corresponding regions of the mandible were then correlated with qualitative scores. Regions were grouped into "non-affected" and "pathologic" based on binarized Likert scores of different imaging hallmarks (0-1 vs 2-3). DCE-MRI measurements among hallmarks were compared using Mann-Whitney-U-testing. ROC (receiver-operating-characteristic) analysis was performed for each of the perfusion parameters to assess diagnostic performance for identification of MRONJ using morphologic ratings as reference standard.

RESULTS

Median perfusion measurements of "pathologic" regions in wash-in, peak enhancement intensity and integrated area under the curve are significantly higher than those of "non-affected" regions, irrespective of reference imaging hallmark (p < 0.05). No significant perfusion differences were found between "pathologic" regions with and without osteolysis (p = 0.180). ROC analysis showed fair diagnostic performance of DCE-MRI parameters for identification of MRONJ (AUC 0.626-0.727).

CONCLUSIONS

DCE bone perfusion parameters are significantly increased in MRONJ compared to non-affected regions, irrespective of osteolysis. Due to certain overlap DCE-MRI bone perfusion cannot serve as full surrogate for UTE bone imaging but may enhance reader confidence.

18F-Fluoride PET/CT Imaging of Medication-Related Osteonecrosis of the Jaw in Conservative Treatment-A Case Report

Medication-related osteonecrosis of the jaw (MRONJ) is a serious side effect in antiresorptive treatment. Treatment of MRONJ is considered primarily conservative with oral mouth rinses and antibiotics but may demand surgery, depending on the complaints and general condition of the patient, the extent of the necrosis, and the overall prognosis with respect to the underlying disease. A 77 year old female patient with invasive ductal breast cancer and bone metastases was treated with intravenous bisphosphonate (BP) zoledronic acid. During therapy, she developed MRONJ in the mandible with severe pain. Clinical examination revealed confluent exposed bone of the lower left jaw and a fistula at the right molar region. The panoramic radiograph revealed a mandibular osseous involvement with diffuse radiopaque areas between radiolucent areas. For preoperative planning, ¹⁸F-fluoride positron emission tomography/computed tomography (PET/CT) of the jaw was performed, showing substantially increased ¹⁸F-fluoride uptake in regions 38 to 47 of the mandible with a focal gap in region 36 (area of clinically exposed bone). CT revealed medullary sclerosis and cortical thickening with confluent periosteal reaction and focal cortical erosion in the regions 37 to 42, whereas the regions 43 to 47 were only subtly sclerotic without cortical thickening. After systemic antibiotic therapy with sultamicillin following significant symptom and pain relief, ¹⁸F-fluoride PET/CT imaging was performed again after 5 months. No changes in either CT and PET were observed in regions 38 to 42, whereas the bony sclerosis was slightly increased in regions 43 to 47 with a slight reduction of ¹⁸F-fluoride uptake. ¹⁸F-fluoride PET/CT showed no significant changes assessing the extent of MRONJ prior and after systemic antibiotic therapy, providing no evidence that conservative treatment reduced the extent of the MRONJ-affected jawbone. The additional information of ¹⁸F-fluoride PET enables to identify the true extent of MRONJ which may be underestimated by CT imaging alone. Patients with MRONJ undergoing conservative treatment could benefit because additional imaging may be avoided as the pre-therapeutic ¹⁸F-fluoride PET/CT delivers all information needed for further treatment. Our findings support the recommendation of a surgical approach as long-term antibiotics cannot downsize the extent of MRONJ.

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.

Practical Approach to Radiopaque Jaw Lesions

Radiopaque lesions of the jaw are myriad in type and occasionally protean in appearance. In turn, the radiologic analysis of these lesions requires a systematic approach and a broad consideration of clinical and imaging characteristics to enable reliable radiologic diagnosis. Initially categorizing lesions by attenuation pattern provides a practical framework for organizing radiopaque jaw lesions that also reflects important tissue characteristics. Specifically, the appearance of radiopaque lesions can be described as (a) densely sclerotic, (b) ground glass, or (c) mixed lytic-sclerotic, with each category representing a distinct although occasionally overlapping differential diagnosis. After characterizing attenuation pattern, the appreciation of other radiologic features, such as margin characteristics or relationship to teeth, as well as clinical features including demographics and symptoms, can aid in further narrowing the differential diagnosis and lend confidence to clinical decision making. The authors review the potential causes of a radiopaque jaw lesion, including pertinent clinical and radiologic features, and outline a simplified approach to its radiologic diagnosis, with a focus on cross-sectional CT. An invited commentary by Buch is available online. ^©RSNA, 2021.

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

Medication-related osteonecrosis of the jaw (MRONJ) is one of the most interesting diseases in the field of maxillofacial surgery. In addition to bisphosphonates, the use of antiresorptive and antiangiogenic agents is known to be the leading cause. However, the exact pathogenesis of MRONJ has not been established, and various hypotheses have been proposed, such as oxidative stress-related theory. As a result, a definitive treatment protocol for MRONJ has not been identified, while various therapeutic approaches are applied to manage patients with MRONJ. Although the surgical approach to treat osteomyelitis of the jaw has been proven to be most effective, there are limitations, such as recurrence and delayed healing. Many studies and clinical trials are being conducted to develop another effective therapeutic modality. The use of some materials, including platelet concentrates and bone morphogenetic proteins, showed a positive effect on MRONJ. Among them, teriparatide is currently the most promising material, and it has shown encouraging results when applied to patients with MRONJ. Furthermore, cell therapy using mesenchymal stem cells showed promising results, and it can be the new therapeutic approach for the treatment of MRONJ. This review presents various treatment methods for MRONJ and their limitations while investigating newly developed and researched molecular and cellular therapeutic approaches along with a literature review.

Gene expression analysis of fresh extraction wounds prior to onset of bisphosphonate-related osteonecrosis of the jaw-like lesions in mice: A preliminary animal study

PURPOSE

The aim of the present study was to investigate the effects of chemotherapeutic/bisphosphonate combination therapy with tooth extraction on gene expression patterns of fresh extraction wounds during initial stages prior to their diagnosis as bisphosphonate-related osteonecrosis of the jaw (BRONJ)-like lesions in mice.

METHODS

Female C57BL/6J mice were used. To create a high-prevalence BRONJ mouse model, combination therapy with the chemotherapy drug cyclophosphamide (CY) and zoledronic acid (ZA) was performed (CY/ZA). Both maxillary first molars were extracted 3 weeks after drug therapy. Saline was used as the control (VC). Soft tissues near the fresh extraction wounds were dissected at 72 h postextraction to investigate the gene expression patterns. Maxillae and long bones at 2 and 4 weeks postextraction were also analyzed.

RESULTS

CY/ZA significantly increased the relative expression levels of IL-6 and decreased those of IL-10 and IGF-1 when compared with those in VC. Moreover, CY/ZA significantly reduced the relative expression levels of CCR-7, cxcl12, cxcr4, and CD105 when compared with those in VC, whereas the level of F4/80 was significantly increased by CY/ZA. Furthermore, CY/ZA significantly decreased the relative expression levels of VEGFA, VEGFB, and VEGFC at 72 h postextraction compared with those in VC.

CONCLUSIONS

Considering that the present study lacked adequate in vitro models, CY/ZA markedly changed the gene expression patterns associated with wound healing from the initial stages prior to onset of BRONJ-like lesions, which may help us to understand the pathophysiology of BRONJ in humans.

Do various imaging modalities provide potential early detection and diagnosis of medication-related osteonecrosis of the jaw? A review

OBJECTIVE

Patients with medication-related osteonecrosis of the jaw (MRONJ) often visit their dentists at advanced stages and subsequently require treatments that greatly affect quality of life. Currently, no clear diagnostic criteria exist to assess MRONJ, and the definitive diagnosis solely relies on clinical bone exposure. This ambiguity leads to a diagnostic delay, complications, and unnecessary burden. This article aims to identify imaging modalities' usage and findings of MRONJ to provide possible approaches for early detection.

METHODS

Literature searches were conducted using PubMed, Web of Science, Scopus, and Cochrane Library to review all diagnostic imaging modalities for MRONJ.

RESULTS

Panoramic radiography offers a fundamental understanding of the lesions. Imaging findings were comparable between non-exposed and exposed MRONJ, showing osteolysis, osteosclerosis, and thickened lamina dura. Mandibular cortex index Class II could be a potential early MRONJ indicator. While three-dimensional modalities, CT and CBCT, were able to show more features unique to MRONJ such as a solid type periosteal reaction, buccal predominance of cortical perforation, and bone-within-bone appearance. MRI signal intensities of vital bones are hypointense on T₁WI and hyperintense on T₂WI and STIR when necrotic bone shows hypointensity on all T₁WI, T₂WI, and STIR. Functional imaging is the most sensitive method but is usually performed in metastasis detection rather than being a diagnostic tool for early MRONJ.

CONCLUSION

Currently, MRONJ-specific imaging features cannot be firmly established. However, the current data are valuable as it may lead to a more efficient diagnostic procedure along with a more suitable selection of imaging modalities.

Medication-Related Osteonecrosis of Jaws (MRONJ) Prevention and Diagnosis: Italian Consensus Update 2020

The Medication-Related Osteonecrosis of Jaws (MRONJ) diagnosis process and its prevention play a role of great and rising importance, not only on the Quality of Life (QoL) of patients, but also on the decision-making process by the majority of dentists and oral surgeons involved in MRONJ prevention (primary and secondary). The present paper reports the update of the conclusions from the Consensus Conference-held at the Symposium of the Italian Society of Oral Pathology and Medicine (SIPMO) (20 October 2018, Ancona, Italy)-after the newest recommendations (2020) on MRONJ were published by two scientific societies (Italian Societies of Maxillofacial Surgery and Oral Pathology and Medicine, SICMF and SIPMO), written on the inputs of the experts of the Italian Allied Committee on ONJ (IAC-ONJ). The conference focused on the topic of MRONJ, and in particular on the common practices at risk of inappropriateness in MRONJ diagnosis and therapy, as well as on MRONJ prevention and the dental management of patients at risk of MRONJ. It is a matter of cancer and osteometabolic patients that are at risk since being exposed to several drugs with antiresorptive (i.e., bisphosphonates and denosumab) or, more recently, antiangiogenic activities. At the same time, the Conference traced for dentists and oral surgeons some easy applicable indications and procedures to reduce MRONJ onset risk and to diagnose it early. Continuous updating on these issues, so important for the patient community, is recommended.

Wound closure and alveoplasty after preventive tooth extractions in patients with antiresorptive intake-A randomized pilot trial

OBJECTIVES

To compare success rates between the sub-periosteal prepared (SPP) muco-periosteal flap and the epi-periosteal prepared (EPP) mucosa flap and the feasibility of alveoplasty after surgical tooth extractions in patients undergoing/after antiresorptive treatment.

SUBJECTS

Patients with an indication for preventive tooth extraction undergoing/after antiresorptive treatment were enrolled over a 24-month period in a parallel-group randomized clinical pilot trial and randomly assigned for primary wound closure to either the SPP or the EPP group. The primary outcome was treatment failure 8 weeks after surgery. To assess the feasibility of alveoplasty, necrotic bone changes at the time point of tooth extraction were evaluated.

RESULTS

One hundred and sixty patients were randomized to the SSP (n = 82) or the EPP (n = 78) group. One hundred and fifty-seven patients met the primary endpoint 8 weeks after surgery with five treatment failures for the SPP group (6.3%) and 18 (23.4%) for the EPP group (p = .004). A significant relationship (p < .0001) was observed between symptomatic teeth and non-vital bone found in 54.8% of all biopsies.

CONCLUSIONS

The strong superiority of the muco-periosteal flap as primary wound closure revealed the feasibility and effectiveness of the study. The large number of necrotic biopsies emphasizes the importance of alveoplasty as a preventive measure.

Use and Evaluation of a Computer-Assisted Examination Method for the Diagnosis and Analysis of Medication-Related Osteonecrosis of the Jaw

The aim of the present study was to analyze the size of the preoperatively calculated defect volume of MRONJ patients (medication-related osteonecrosis of the jaw) and to develop a computer-aided tool based on techniques of AI (artificial intelligence) that facilitates diagnostics of MRONJ. For this purpose, on the basis of 3D (three-dimensional) data sets of 175 MRONJ patients, the outline of the necrosis was marked with the software iPlan 3.0.5 (BrainLAB AG) thus determining the respective volume. The correlation of this volume with other 31 collected parameters was analyzed retrospectively. There was a significant correlation between the defect volume on the one hand, and the MRONJ stage, the number of performed operations, and the therapy invasiveness on the other hand. Furthermore, it could be shown that in one third of the cases no defects could be recognized in the 2D imaging by panoramic radiograph,  while in the 3D data sets defects already had been demarcated. On the basis of these data, a computer-aided tool based on the principles of AI was developed and validated, which might allow the automated calculation of the 3D defect extension and classification of the MRONJ cases into a ranking system. In conclusion, preparation of a 3D image can be recommended for reliably making the diagnosis "MRONJ." Moreover, knowledge of the exact defect volume serves as a decision-making aid with regard to the choice of therapy, ensures intraoperative certitude, and allows an assessment of the prognosis.

Distinct immunopathology in the early stages between different antiresorptives-related osteonecrosis of the jaw-like lesions in mice

There is limited information about denosumab-related osteonecrosis of the jaw (DRONJ), unlike bisphosphonate-related ONJ (BRONJ). The mode of action is clearly different between denosumab and bisphosphonates. DRONJ occurs mainly following tooth extraction in cancer patients treated with the combination of denosumab and other drugs including chemotherapy. However, DRONJ animal models similar to these clinical situations have not been developed. The aims of this study were to 1) create a new model of high-prevalence chemotherapy/anti-RANKL antibody-related ONJ-like lesions to mimic patients receiving a denosumab/chemotherapy combination; and 2) compare the histopathological and immunopathological findings in the early stages of BRONJ-like and anti-RANKL antibody-related ONJ-like lesions. Cyclophosphamide (CY) and anti-mouse RANKL monoclonal antibody (mAb) or zoledronate combination therapy (CY/mAb and CY/ZA, respectively) was performed to create ONJ-like lesions in female C57BL/6J mice. Both maxillary first molars were extracted at 3 weeks after drug administration. The animals were euthanized at either 2 or 4 weeks after tooth extraction. Increased necrotic bone and empty lacunae with decreased living bone and osteocyte numbers were common histopathological findings in CY/mAb- and CY/ZA-induced impaired wound healing at 4 weeks after tooth extraction, and they were diagnosed as ONJ-like lesions based on validation of BRONJ and DRONJ in humans. In areas of impaired healing at 2 weeks post-extraction, decreases in angiogenesis and F4/80⁺LYVE-1^- macrophages were noted as common immunopathological findings, although anti-angiogenesis was worse with CY/mAb than with CY/ZA. Interestingly, CY/mAb did not reduce F4/80⁺LYVE-1⁺ cells and normal lymphangiogenesis remained, whereas CY/ZA profoundly suppressed the larger size of F4/80⁺LYVE-1⁺ cells, similar to vessels with a concomitant decrease in lymphangiogenesis. Therefore, the distribution of the larger size of F4/80⁺LYVE-1⁺ cells differed in the early stages between different antiresorptive-induced ONJ-like lesions in conjunction with lymphangiogenesis, although the histopathological findings were similar. These findings suggest that the pathogenesis of BRONJ and DRONJ may differ due to the distributions of F4/80⁺LYVE-1⁺ tube-like-structured cells.

Skeletal Site-Specific Response of Jawbones and Long Bones to Surgical Interventions in Rats Treated with Zoledronic Acid

Bisphosphonates (BPs) have been extensively used for management of bone diseases with pathologically high resorption. Despite the great clinical benefits, a severe complication known as medication-related osteonecrosis of the jaw (MRONJ) has been reported. It is found that most of the reported MRONJ cases were limited in the jawbones/craniofacial bones instead of long bones. The present study aims to investigate the differential bone response to surgical procedures between jawbones and long bones exposed to BPs. Forty-eight skeletal mature Sprague Dawley female rats were administered oncologic dose of zoledronic acid (ZA) or normal saline for 4 weeks and then subjected to tooth extraction on the mandible and maxilla, and a bone defect creation on the femur. After surgical procedures, ZA or saline treatment were continued until sacrifice at week 2, week 4, and week 8, post-operatively. The samples were subjected to micro-computerized tomography (micro-CT) and histological assessment. Osteonecrosis was only found in jawbones in ZA-treated rats. ZA-treated rats showed significantly higher bone mineral density with greater bone volume in all surgical sites than that in the controls. The length of exposure of ZA did not seem to affect trabecular microstructure, and it only showed higher bone volume and BMD with longer healing time which is expected in the healing process.

Symposium: Imaging modalities for drug-related osteonecrosis of the jaw (4), CT and MR imaging findings of antiresorptive agent-related osteonecrosis of the jaws/medication-related osteonecrosis of the jaw (secondary publication)

Generally, CT and MR images of antiresorptive agent-related osteonecrosis of the jaw (ARONJ)/medication-related osteonecrosis of the jaw (MRONJ) show nonspecific findings as seen in active osteomyelitis．However, there are some characteristics as follows; unilateral maxillary sinusitis adjacent to ipsilateral maxillary ARONJ/MRONJ, DRONJ presenting larger sequestrum and periosteal reaction more frequently than BRONJ, BRONJ resulting from intravenous administration of the drug presenting larger and more frequent buccolingual cortical bone perforations than BRONJ from oral administration, and better diagnostic accuracy of extent of perilesional soft tissue inflammation on MR imaging than CT. The CT and MR imaging features of ARONJ/MRONJ are summarized in this report.

From Osteoclast Differentiation to Osteonecrosis of the Jaw: Molecular and Clinical Insights

Bone physiology relies on the delicate balance between resorption and formation of its tissue. Bone resorption depends on a process called osteoclastogenesis in which bone-resorbing cells, i.e., osteoclasts, are produced by the differentiation of more undifferentiated progenitors and precursors. This process is governed by two main factors, monocyte-colony stimulating factor (M-CSF) and receptor activator of NFκB ligand (RANKL). While the former exerts a proliferating effect on progenitors/precursors, the latter triggers a differentiation effect on more mature cells of the same lineage. Bone homeostasis requires a perfect space–time coordination of the involved signals. When osteoclastogenesis is poorly balanced with the differentiation of the bone forming counterparts, i.e., osteoblasts, physiological bone remodelling can turn into a pathological state, causing the systematic disruption of bone tissue which results in osteopenia or osteolysis. Examples of these conditions are represented by osteoporosis, Paget’s disease, bone metastasis, and multiple myeloma. Therefore, drugs targeting osteoclastogenesis, such as bisphosphonates and an anti-RANKL monoclonal antibody, have been developed and are currently used in the treatment of such diseases. Despite their demonstrated therapeutic efficacy, these agents are unfortunately not devoid of side effects. In this regard, a condition called osteonecrosis of the jaw (ONJ) has been recently correlated with anti-resorptive therapy. In this review we will address the involvement of osteoclasts and osteoclast-related factors in the pathogenesis of ONJ. It is to be hoped that a better understanding of the biological mechanisms underlying bone remodelling will help in the design a medical therapeutic approach for ONJ as an alternative to surgical procedures.

A comparison of the cone beam computed tomography findings in medication-related osteonecrosis of the jaws related to denosumab versus bisphosphonates: an observational pilot study

OBJECTIVE

The aim of this study was to compare the radiographic abnormalities on cone beam computed tomography (CBCT) in patients with medication-related osteonecrosis of the jaws (MRONJ) related to denosumab use versus bisphosphonate use.

STUDY DESIGN

The study included 34 consecutive patients with MRONJ who had a history of exclusive use of denosumab (n = 17) or bisphosphonates (n = 17) and had undergone CBCT for determination of extent of disease. Demographic data of the patients were collected. Differences in radiologic characteristics between patients with denosumab-related osteonecrosis of the jaws (DRONJ) and those with bisphosphonate-related osteonecrosis of the jaws (BRONJ) were scored and studied on CBCT.

RESULTS

In patients with DRONJ, sequestra (P = .015) and lysis of the cortical border of the jaw (P = .033) were significantly less common than in patients with BRONJ. Subperiosteal bone formation did not differ between the groups (P = .545). There was no association between stage of disease and duration of drug therapy or duration of symptoms for either medication group.

CONCLUSIONS

The radiologic features of DRONJ may be different from those of BRONJ with regard to the presence of sequestra and cortical lysis and might, therefore, be improperly diagnosed. Underestimation and undertreatment of DRONJ may potentially lead to progression of disease and, thus, make treatment more difficult.

Histologic analysis of medication-related osteonecrosis of the jaw compared with antiresorptive-exposed bone and other infectious, inflammatory, and necrotic jaw diseases

OBJECTIVE

This study characterized histologic features of medication-related osteonecrosis of the jaw (MRONJ) through analysis of tissues from patients and healthy individuals.

STUDY DESIGN

Bone biopsies were collected from various infectious, inflammatory, and necrotic jaw diseases. Samples were divided into bone exposed to bisphosphonates or denosumab, as well as bisphosphonate-related osteonecrosis of the jaw (BRONJ), denosumab-related osteonecrosis of the jaw (DRONJ), and mixed necrosis, enabling us to identify features of single agent necrosis without influence from previous therapies. Hematoxylin and eosin (H&E), receptor activator of nuclear factor κ-Β ligand (RANKL), tartrate-resistant acid phosphatase (TRAP), osteoprotegerin, toluidine blue, CD14, and CD68 staining and micro-computed tomography (micro-CT) analysis were performed. Groups were compared by using analysis of variance (ANOVA).

RESULTS

In total, 156 bone samples were collected from 105 patients. MRONJ variants exhibited more infectious infiltration. Bisphosphonate (P < .001) and mixed necrosis (P = .002) demonstrated more RANKL- and TRAP-positive osteoclasts. Denosumab necrosis (P = .007), and bone exposed to bisphosphonates (P = .028) in combination with denosumab (P = .022) demonstrated significantly lower numbers of osteocytes per area. CD14 and CD68 positivity was increased for BRONJ (P = .008; P < .001, respectively). MRONJ variants exhibited the widest trabecular width and decreased medullary space to bone. No diminished vascular network in MRONJ samples was observed.

CONCLUSIONS

Histologic features differ among MRONJ variants, with oversuppressed bone turnover, dysfunctional bone resorption, and a disturbed osteocyte network as potential mechanisms of pathogenesis.

Systemic administration of quality- and quantity-controlled PBMNCs reduces bisphosphonate-related osteonecrosis of jaw-like lesions in mice

BACKGROUND

Definitive treatment strategies for bisphosphonate-related osteonecrosis of the jaw (BRONJ) have not been developed. Cell-based therapy is an attractive treatment method for intractable diseases in the medical and dental fields; however, approval has been challenging in dentistry. Recently, we developed quality- and quantity (QQ)-controlled peripheral blood mononuclear cells (PBMNCs) that have anti-inflammatory and pro-angiogenesis effects. The aim of this study was to investigate the effects of QQ-controlled PBMNC transplantation on BRONJ-like lesions in mice.

METHODS

To create high-prevalence BRONJ-like lesions, cyclophosphamide (CY) and zoledronate (ZA) were used with tooth extraction. Drug treatment was performed for 5 weeks. QQ-controlled PBMNC transplantation was performed immediately following tooth extraction of both maxillary first molars at 3 weeks after drug administration. Mice were euthanized at 2 weeks post-extraction. Histomorphometric and immunohistochemical analyses, microcomputed tomography assessment, and quantitative polymerase chain reaction evaluation were conducted using maxillae and long bones.

RESULTS

ZA effects on long bones were noted, regardless of CY. Severely inhibited osseous and soft tissue wound healing of tooth extraction sockets was induced by CY/ZA combination therapy, which was diagnosed as BRONJ-like lesions. QQ-controlled PBMNC transplantation reduced BRONJ-like lesions by improving soft tissue healing with increased M1 and M2 macrophages and enhanced neovascularization in the connective tissue of tooth extraction sockets. QQ-controlled PBMNC transplantation also reduced inflammation by decreasing polymorphonuclear cells and TNF-α expression in the tooth extraction sockets. Additionally, QQ-controlled PBMNC transplantation partially improved osseous healing of tooth extraction sockets. Interestingly, only 20,000 QQ-controlled PBMNCs per mouse induced these transplantation effects. QQ-controlled PBMNC transplantation did not affect the systemic microenvironment.

CONCLUSIONS

Our findings suggest that transplantation of a small amount of QQ-controlled PBMNCs may become novel therapeutic or prevention strategies for BRONJ without any adverse side effects.

Three-dimensional radiologic-pathologic correlation of medication-related osteonecrosis of the jaw using 3D bone SPECT/CT imaging

OBJECTIVES

The aim of this study was to assess a three-dimensional (3D) correlation between preoperative 3D bone single photon emission CT (SPECT)/CT, which allows the visualization of radiotracer uptake on 3D volume-rendered CT images, and histopathological characteristics in the medication-related osteonecrosis of the jaw (MRONJ).

METHODS

We conducted a full histopathological assessment of the resected jaws in four patients with Stage 2 or 3 MRONJ. The pathologic results were classified as follows: necrosis without any tissue vascularity (N + V-), necrosis with both vascularity and acute inflammatory cell infiltration due to bacterial infection (N + V+I+), necrosis with regenerative vasculature but no inflammatory cell infiltration (N + V+I-), and chronic inflammation without massive necrosis (N-V +I+). These classifications were correlated with imaging results.

RESULTS

The N + V- areas visually represented the area of necrotic bone exposed to the oral cavity and were consistent with defect area of radioisotope uptake in SPECT/CT. The N + V- areas were surrounded by the N + V+I + areas where increased radiotracer uptake was clearly seen. Also, abnormal uptake was found in both of the N + V+I- and N-V +I+ areas. The extensive surgical resections from necrotic core to bloody viable margins were performed in all cases, although one had the recurrence of MRONJ at the margin showing abnormal uptake that histologically represented the N + V+I- area.

CONCLUSIONS

Radiologic-pathologic correlation of MRONJ could be achieved using 3D SPECT/CT. The presence of regenerative vascularity with necrosis or inflammation seemed to determine bone metabolism in MRONJ. The recurrence of MRONJ was observed in one case, and 3D SPECT/CT had preoperatively depicted the recurrence site.

Symposium: Imaging modalities for drug-related osteonecrosis of the jaw (1), role of imaging in drug-related osteonecrosis of the jaw: An up-to-date review (secondary publication)

MRONJ/ARONJ is a serious adverse effect of medication, although the incidence of the disease is rare, and there are still controversial issues regarding the pathogenesis of MRONJ/ARONJ. Medications that can lead to MRONJ/ARONJ are commonly used to treat osteoporosis and to prevent bone fractures caused by bone metastasis of malignancies. The long-standing disease state of ONJ deteriorates the quality of life of affected patients. Early detection and prevention of the disease are key to alleviating pain and discomfort. To date, several imaging modalities have been introduced to depict the lesions. Imaging modalities, radiography, CT, MRI and nuclear medicine provide important information for managing this challenging disease.

Medication related osteonecrosis of the jaw in osteoporotic vs oncologic patients-quantifying radiographic appearance and relationship to clinical findings

OBJECTIVES

To explore whether differences exist in the clinical and radiographic presentation of oncologic vs osteoporotic patients with medication-related osteonecrosis of the jaw (MRONJ).

METHODS

We retrospectively assessed panoramic radiographs and CBCT examinations of 70 MRONJ patients receiving antiresorptive medications for the management of either osteoporosis or bone malignancy. Radiographic features of MRONJ were documented and categorized according to severity. A composite radiographic index (CRI) was constructed to account for the heterogeneity in radiographic manifestations of MRONJ and further stratify extent of osseous changes.

RESULTS

Patients with osteoporosis were mostly older females and presented more frequently with Stage 2 MRONJ, while patients with malignancy were equally distributed between males and females, and presented mostly with Stage 1 MRONJ. Most MRONJ lesions in oncologic patients occurred in the mandible, whereas the maxilla and mandible were equally affected in osteoporotic patients. Patients with minimal radiographic changes (low CRI score) often presented with MRONJ in dentate areas, while most patients in medium and high CRI groups presented with MRONJ after recent tooth extraction. The low CRI group consisted of primarily oncologic patients, while osteoporotic vs oncologic patients were divided more evenly in the other CRI groups (p = 0.083). While CRI scores increased with clinical staging, a Spearman's rank correlation coefficient of 0.49 suggests that clinical appearance does not reliably predict osseous changes.

CONCLUSIONS

Our data identify differences in the MRONJ appearance of patients with osteoporosis vs malignancy and emphasize the significance of detailed radiographic assessment, in addition to the clinical appearance, in characterizing the osseous changes of the disease.

CT imaging features of antiresorptive agent-related osteonecrosis of the jaw/medication-related osteonecrosis of the jaw

OBJECTIVES

Antiresorptive agent-related osteonecrosis of the jaw (ARONJ)/medication-related osteonecrosis of the jaw (MRONJ) include both bisphosphonate-related osteonecrosis of jaw (BRONJ) and denosumab-related osteonecrosis of jaw (DRONJ). The purpose of this study is to study radiological characteristics of ARONJ/MRONJ. These imaging features may serve as one useful aid for assessing ARONJ/MRONJ.

METHODS

CT scans of 74 Japanese patients, who were clinically diagnosed by inclusion criteria of ARONJ/MRONJ, obtained between April 1, 2011 and September 30, 2016, were evaluated. We investigated the CT imaging features of ARONJ/MRONJ, and clarified radiological differentiation between BRONJ and DRONJ, BRONJ due to oral bisphosphonate administration and due to intravenous bisphosphonate administration, BRONJ with respective kinds of medication, BRONJ with long-term administration and short-term administration, BRONJ with each clinical staging respectively. Fisher's exact test, χ² test, Student's t-test and analysis of variance were performed in the statistical analyses.

RESULTS

Unilateral maxillary sinusitis was detected in all patients with upper ARONJ/MRONJ (100%). DRONJ showed large sequestrum more frequently than BRONJ (3/4, 75 vs 3/35, 8.6%, p < 0.05). DRONJ showed periosteal reaction more frequently than BRONJ (4/10, 40 vs 7/65, 10.1%, p < 0.05). Patients of BRONJ resulting from intravenous bisphosphonate administration showed larger and more frequent buccolingual cortical bone perforations than BRONJ resulting from oral bisphosphonate administration (7/8, 87.5 vs 11/30, 36.7%, p < 0.05). There was no significant correlation between CT findings and respective kinds of medication, long/short-term administration, clinical stages of BRONJ.

CONCLUSIONS

ARONJ/MRONJ has characteristic CT image findings which could be useful for its assessment.

Bisphosphonate-induced osteonecrosis of the jaw in patients with bone metastatic, hormone-sensitive prostate cancer. Risk factors and prevention strategies

Aims and background

Evidence from the literature suggests that osteonecrosis of the jaw is emerging as a serious complication of treatment with bisphosphonates for patients with advanced prostate cancer.

Methods and study design

This study is a series of 60 patients with osseous metastases from prostate cancer under complete androgen deprivation therapy. All patients also received bisphosphonates intravenously every 3 to 4 weeks. Over a period of 3 and a half years, we recorded the incidence, presenting signs and symptoms of osteonecrosis of the jaw among those patients and the diagnostic workup required.

Results

Nine of the 60 patients with metastatic prostate cancer were found to be affected with osteonecrosis of the jaw secondary to bisphosphonate administration at the Urology Department at the University Hospital of Alexandroupolis between January 2006 and August 2009. For diagnostic reasons, all 9 patients underwent computed tomography scan and magnetic resonance imaging of the maxillary region, as well as a three-phase whole body bone scan.

Conclusions

There is evidence that administration of bisphosphonates in patients with advanced prostate cancer may increase the risk of osteonecrosis of the jaw. Guidelines regarding the diagnosis and management of those patients are needed.

Transplantation of Noncultured Stromal Vascular Fraction Cells of Adipose Tissue Ameliorates Osteonecrosis of the Jaw-Like Lesions in Mice

The precise pathoetiology and effective treatment strategies for bisphosphonate-related osteonecrosis of the jaw (BRONJ) remain unknown. Transplantation of noncultured stromal vascular fraction (SVF) cells has been shown to be a useful method for regenerative medicine in place of stem cell therapy. This study investigated the effects of noncultured SVF transplantation on tooth extraction socket healing in mice. Both chemotherapeutic/bisphosphonate combination therapy for 7 weeks and tooth extraction of maxillary first molars at 3 weeks after drug administration were performed using female C57BL/6J mice. Osseous and soft tissue wound healing were validated at 4 weeks postextraction using gross wound healing and histomorphometry. Here, we created a new animal model of high-prevalence ONJ-like lesions that mimic human progression, because human ONJ mainly occurs in female patients taking both chemotherapeutic and bisphosphonate following tooth extraction. Moreover, mice with chemotherapeutic and bisphosphonate combination therapy for 5 weeks received SVF transplantation just after tooth extraction at 3 weeks post-drug administration. Euthanasia was performed at 2 weeks postextraction to assess the transplantation effects on wound healing using gross wound healing, histomorphometry, immunohistomorphometry, quantitative real-time polymerase chain reaction, and microcomputed tomography. We showed that systemic transplantation of noncultured SVF cells ameliorates ONJ-like lesions by improving both osseous and soft tissue healing of tooth extraction sockets. SVF therapy significantly increased blood vessels and the ratio of M2/M1 macrophages. In addition, SVF transplantation reduced the increases in tartrate-resistant acid phosphatase-positive (TRAP⁺ ) mononuclear cells (MNCs) and nonattached osteoclasts from the bone surface, which were significantly detected in the connective tissue of tooth extraction sockets and bone marrow by chemotherapeutic/bisphosphonate combination therapy. Our findings suggest that transplantation of noncultured SVF cells is a suitable treatment for BRONJ. Abnormal TRAP⁺ MNCs and nonattached osteoclasts in systemic and local environments may contribute to the development of BRONJ. © 2017 American Society for Bone and Mineral Research.

Osseous changes in patients with medication-related osteonecrosis of the jaws

OBJECTIVES

Medication-related osteonecrosis of the jaw (MRONJ) is a severe side effect of antiresorptive agents. The aim of this study was to investigate the osseous changes in patients with MRONJ.

METHODS

Cone beam CT (CBCT) images of 25 patients with MRONJ and controls were retrospectively evaluated. Buccal, lingual, apical cortical bone thicknesses; buccal, lingual, apical intracortical and cancellous bone density; diameter of mental foramen and incisive canal, and width of mental foramen were measured.

RESULTS

Buccal and apical cortical bone thicknesses were increased; however intracortical radiodensity values decreased in the Study Group when compared with the Control Group (p = 0.007, p = 0.001). Narrowing of incisive canal was observed in patients with MRONJ (p = 0.000).

CONCLUSIONS

Clinician should have awareness about narrowing of incisive canal, apical and buccal cortical bone thickening, decreasing in cancellous bone radiodensity, and the lingual cortex destruction in patients with MRONJ.

Antiresorptive treatment-associated ONJ

Osteonecrosis of the jaw (ONJ) is a severe complication of therapy with antiresorptive agents (e.g. bisphosphonates and denosumab), which are used to manage bone metastases from cancer, to reduce the incidence of skeletal-related events. Available data indicate that 0-27, 5% of patients exposed to antiresorptive agents may develop ONJ, depending on the number of infusions and the duration of therapy. Besides antiresorptive therapy, a number of risk factors for osteonecrosis have been identified. Oral surgical procedures, tooth extractions and infection to the jawbones are considered the main risk factors for developing ONJ, when receiving antiresorptive therapy. However, a growing number of patients develop ONJ without apparent risk factors, raising concern for other predisposing factors. Jaw bone necrosis may be irreversible, resulting in a chronic disease with negative impact on the quality of patients' lives. The role of risk reduction strategies like meticulous dental screening and optimal oral hygiene is fundamental for preventing development of ONJ. ONJ is usually treated conservatively to relieve the symptoms and manage jaw bone necrosis. In certain cases, surgical intervention is required. Future research should emphasize individual predisposition to ONJ, more effective preventive measures and more efficient therapeutic procedures.

Elevation of pro-inflammatory cytokine levels following anti-resorptive drug treatment is required for osteonecrosis development in infectious osteomyelitis

Various conditions, including bacterial infection, can promote osteonecrosis. For example, following invasive dental therapy with anti-bone resorptive agents, some patients develop osteonecrosis in the jaw; however, pathological mechanisms underlying these outcomes remain unknown. Here, we show that administration of anti-resorptive agents such as the bisphosphonate alendronate accelerates osteonecrosis promoted by infectious osteomyelitis. Potent suppression of bone turnover by these types of agents is considered critical for osteonecrosis development; however, using mouse models we found that acceleration of bone turnover by teriparatide injection did not prevent osteonecrosis but rather converted osteoclast progenitors to macrophages expressing inflammatory cytokines, which were required for osteonecrosis development. In fact, we demonstrate that TNFα-, IL-1α/β- or IL-6-deficient mice as well as wild-type mice administered a TNFα-inhibitor were significantly resistant to development of osteonecrosis accompanying infectious myelitis, even under bisphosphonate treatment. Our data provide new insight into mechanisms underlying osteonecrosis and suggest new ways to prevent it.

Interrelationship of clinical, radiographic and haematological features in patients under bisphosphonate therapy

OBJECTIVES

To analyze the clinical, radiographic and haematological aspects of patients under bisphosphonate therapy.

METHODS

A retrospective study was conducted where the records of patients taking bisphosphonates were analyzed considering the occurrence of bisphosphonate-related osteonecrosis of the jaw (BRONJ). Evaluation included panoramic and periapical radiographies, haematological examinations and clinical features. Radiographies were analyzed determining the presence or absence of bone sclerosis, osteolysis, persisting alveolar socket, narrowing of the mandibular canal, widening of the periodontal ligament space, periradicular radiolucency, sequestrum and thickening of the lamina dura. Laboratory tests consisted of complete blood count, fasting serum glucose, erythrocyte sedimentation rate (ESR) and serum levels of calcium, phosphorus, alkaline phosphatase, parathormone (PTH) and C-terminal telopeptide of collagen I (CTX).

RESULTS

Alkaline phosphatase and ESR were significantly higher in the BRONJ group, whereas fasting serum glucose, CTX, PTH, calcium and phosphorus did not significantly differ. BRONJ showed association with smoking, tooth extraction, anaemia and leukocytosis. On radiographic analysis, persisting alveolar socket, osteolysis, bone sclerosis and narrowing of the mandibular canal were significantly more prevalent in the BRONJ group. Thickening of the lamina dura, periapical radiolucencies, widening of the periodontal ligament space and sequestrum did not significantly differ between the groups.

CONCLUSIONS

BRONJ is a multifactorial disease with high morbidity, which requires experimental studies to clarify the role of the reported risk factors and clinical radiographic signs to improve its diagnosis.