Oral Bisphosphonate-Induced Osteonecrosis: Risk Factors, Prediction of Risk Using Serum CTX Testing, Prevention, and Treatment

The association between inflammatory biomarkers and low back disorder: a systematic review and meta-analysis

INTRODUCTION

Low back disorder (LBD) is a major cause of disability worldwide. Inflammation results in proliferation of cytokines or consequent degradation products (collectively known as inflammatory biomarkers) that activate pain pathways which can result in non-specific LBD. This systematic review and meta-analysis aim to evaluate the relationship between inflammatory biomarkers and clinical outcomes in patients with LBD.

METHODS

The PRISMA guideline was followed for the systematic reivew. Three online databases were searched. Four RCTs and sixteen observational studies with 1142 LBD patients were analysed. The primary outcomes were back and leg pain scores, back-specific disability scores and expression of inflammatory biomarkers. Standardized mean difference (SMD) and their 95% confidence intervals (CI) were evaluated. The Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach was used to summarize the strength of evidence.

RESULTS

Four RCTs and sixteen observational studies were included in the analysis of 1142 patients with LBD. There was a statistically significant reduction in back pain score and IL-1 beta and increase in the expression of CTX-1 and IL-10 levels post treatment. There was a significant relationship between increase in the expression of MCP- and reduction in the expression of hsCRP with increase in back pain. Significant relationship was also observed between increase in the expression of MCP-1 and reduction in the expression of IL-6 with increase in leg pain. Increase in the expression of IL-8 and reduction in the expression of hsCRP was also associated with increased disability score.

CONCLUSION

Inflammatory biomarkers play a significant role in the pathogenesis of LBD. CTX-1, IL-10 and IL-1 beta may be responsible for the decrease in back pain scores post treatment. There is a relationship between MCP-1, IL-6, IL-8 and hsCRP with clinical and functional assessments for LBD. Further studies will improve understanding of the pathogenesis of LBD and aid in targeted management strategies.

Medication-Related Osteonecrosis of the Jaw: A Cross-Sectional Study on the Prevalence of Cutaneous Manifestations and the Primary Care Physician's Role in its Early Diagnosis

BACKGROUND

Medication-related osteonecrosis of the jaw (MRONJ) is a side effect in patients undergoing treatment with bone-modifying agents (BMA) for cancer or osteoporosis. Although most cases are treated by oral medicine specialists, some cases may present extraorally as a fistula in the skin or erythematous swelling localized to the jaw area, causing these patients to consult a primary care physician. This study examined the prevalence and clinical characteristics of extraoral manifestations of MRONJ in a large cohort to raise awareness among primary care physicians of this entity, enabling prompt diagnosis and treatment.

METHODS

Medical records were retrieved of patients diagnosed with MRONJ between 2003 and June 2020 in the Oral Medicine Unit of The Sheba Medical Center, Israel. Data relating to demographics, medical background, type of BMA, and clinical presentation were collected.

RESULTS

In total, 515 patients (378 women [73%] and 137 men [27%]; mean age: 65 years, range: 32-94 years) met the inclusion criteria, among whom 84 (16.5%) presented with extraoral manifestations of MRONJ. Of these 84 patients, 21 (24.7%) presented with extraoral fistulas. Extraoral manifestations were strongly correlated with MRONJ of the mandible (n = 67; P = .0006).

CONCLUSIONS

MRONJ is a significant side effect of BMA therapy. Although MRONJ mostly presents intraorally, some patients may initially present with extraoral manifestations of erythematous swelling or fistulas localized to the jaw area. Primary care physicians should consider MRONJ as a differential diagnosis in such patients.

Navigating the complexities and controversies of medication-related osteonecrosis of the jaw (MRONJ): a critical update and consensus statement

OBJECTIVES

To provide a critical update identifying the knowledge gaps and controversies in medication-related osteonecrosis of the jaw (MRONJ) within the Belgian healthcare context and outline opportunities for improvement and research in these areas.

METHODS

A literature review was performed to identify guidelines from international clinical societies in oncology or oral and maxillofacial surgery on diagnosing, preventing, and treating MRONJ. The recommendations were critically assessed in light of recent developments in the field and confronted with the clinical experience of experts.

RESULTS

Despite progress in the diagnostic criteria of MRONJ, the continued need for an 8-week timeout period should be reconsidered. Furthermore, 3D imaging techniques should be introduced to improve diagnosis and staging. The staging system remains ambiguous regarding Stage 0 MRONJ, and ongoing confusion exists regarding the term non-exposed MRONJ. The prevention of MRONJ should be tailored, considering the individual patient's risk of MRONJ, frailty, and life expectancy. More research seems needed into the efficacy and safety of drug holidays, considering the risks of rebound remodeling on fractures. With renewed interest in surgical and adjunct management techniques, adequately designed clinical studies are needed to help translate trial outcomes into universally applicable treatment guidelines taking into account individual patient characteristics.

CONCLUSIONS

Important knowledge gaps remain and hamper the development of clinical guidelines. Several controversies were identified where consensus is lacking, and further harmonization between stakeholders is necessary. Finally, the need for randomized controlled comparative clinical trials in MRONJ resonates harder than ever to identify the best treatment for individual patients.

Assessing dental surgeons' understanding of bisphosphonates: Implications for patient health in oral surgery

Objectives

This study aimed to analyze the knowledge of dental surgeons concerning the pharmacological effects of bisphosphonates (BP) and their impact on the health of patients undergoing oral surgery treatment.

Materials and methods

A quantitative study was conducted with professionals in the Cariri region of Ceará, Brazil. The data were collected using a semi-structured questionnaire to interview the dental surgeons who met the inclusion criteria. The data were analyzed by Chi-square and Fischer's Exact tests using the SPSS program version 22.0.

Results

The results indicated that most interviewed subjects have no experience with the dental treatment of individuals under treatment with bisphosphonates. When a sample of the medication was presented, a significant number of the participants (65.3%) did not recognize the drug. Among those who recognized it, 66.5% did not know how to treat bisphosphonate-using patients in the clinical routine. However, 95.1% of the professionals who recognized the need to discontinue these drugs admitted contacting the prescriber to establish the best dental conduct. Our results also showed that recently graduated professionals better understood the need to stop BP use before invasive treatment, although they did not know the protocol.

Conclusion

In conclusion, a better knowledge of the pharmacological effects of BP is crucial for conducting adequate anamnesis, requesting additional tests, and performing medical monitoring, which has a significant impact on the clinical practice of dental surgeons.

Clinical Impact on Dental Implant Survival in Patients Taking Antiresorptive Medications: A Systematic Review and Meta-Analysis

Dental implants are a predictable option to replace missing teeth. Patients on antiresorptive medications used to treat disorders associated with bone resorption may need dental implants to replace missing teeth. The data on implant failure in patients on antiresorptive medication requiring dental implants, is conflicting and limited. This systematic review aims to investigate if antiresorptive medications have any clinical impact on dental implant survival. Electronic databases were searched until May 2020. The focus question (PICOS): Participants: humans, Interventions: implant placement surgery in patients on antiresorptive medication, Comparisons: patients on antiresorptive medication vs control (patients not on antiresorptive medication), Outcomes: implant survival, and Study design: clinical studies. The protocol of this systematic review was registered in PROSPERO (CRD42020209083). Fourteen nonrandomized studies were selected for data extraction and risk of bias assessment using the ROBINS-1 tool. Only studies with a control were included for the meta-analysis, 8 articles were included in the meta-analysis using implant-level data, and 5 articles were included in the meta-analysis using patient-level data. There was no statistical significance between the 2 groups at the patient level based on 265 patients. However, there was a statistically significant difference at the implant level based on 2697 implants. Therefore, antiresorptive medications, mainly bisphosphonates (BPs), may significantly contribute to implant failure. Antiresorptive medications, especially BPs may reduce implant survival and impair the osseointegration of dental implants. Failed implants in patients on BPs may not lead to osteonecrosis and may be replaced with success.

CREB1 alleviates the apoptosis and potentiates the osteogenic differentiation of zoledronic acid-treated human periodontal ligament stem cells via up-regulating VEGF

Periodontitis represents a severe inflammatory illness in tooth supporting tissue. It has been supported that cAMP response element binding protein 1 (CREB1), a common transcription factor, extensively participates in osteogenic differentiation. Here, the current study was to look into the impacts of CREB1 on the process of periodontitis and its possible action mechanism. After human periodontal ligament stem cells (PDLSCs) were challenged with zoledronic acid (ZA), CREB1 expression was examined with RT-qPCR and western blotting. CCK-8 assay appraised cell activity. Following CREB1 elevation or/and vascular endothelial growth factor (VEGF) silencing in ZA-treated PDLSCs, CCK-8 and TUNEL assays separately estimated cell viability and apoptosis. Western blotting tested the expression of apoptosis- and osteogenic differentiation-associated proteins. ALP staining measured PDLSCs osteogenic ability and ARS staining estimated mineralized nodule formation. JASPAR predicted the potential binding of CREB1 with VEGF promoter, which was then testified by ChIP and luciferase reporter assays. RT-qPCR and western blotting tested VEGF expression. CREB1 expression was declined in ZA-exposed PDLSCs and CREB1 elevation exacerbated the viability and osteogenic differentiation while obstructed the apoptosis of PDLSCs. Additionally, CREB1 bond to VEGF promoter and transcriptionally activated VEGF expression. Further, VEGF absence partially stimulated the apoptosis while suppressed the osteogenic differentiation of CREB1-overexpressing PDLSCs treated by ZA. To be concluded, CREB1 might activate VEGF transcription to obstruct the apoptosis while contribute to the osteogenic differentiation of ZA-treated PDLSCs.

Enhancement of the therapeutic efficacy of the MAP regimen using thiamine pyrophosphate-decorated albumin nanoclusters in osteosarcoma treatment

Recent studies on osteosarcoma regimens have mainly focused on modifying the combination of antineoplastic agents rather than enhancing the therapeutic efficacy of each component. Here, an albumin nanocluster (NC)-assisted methotrexate (MTX), doxorubicin (DOX), and cisplatin (MAP) regimen with improved antitumor efficacy is presented. Human serum albumin (HSA) is decorated with thiamine pyrophosphate (TPP) to increase the affinity to the bone tumor microenvironment (TME). MTX or DOX (hydrophobic MAP components) is adsorbed to HSA-TPP via hydrophobic interactions. MTX- or DOX-adsorbed HSA-TPP NCs exhibit 20.8- and 1.64-fold higher binding affinity to hydroxyapatite, respectively, than corresponding HSA NCs, suggesting improved targeting ability to the bone TME via TPP decoration. A modified MAP regimen consisting of MTX- or DOX-adsorbed HSA-TPP NCs and free cisplatin displays a higher synergistic anticancer effect in HOS/MNNG human osteosarcoma cells than conventional MAP. TPP-decorated NCs show 1.53-fold higher tumor accumulation than unmodified NCs in an orthotopic osteosarcoma mouse model, indicating increased bone tumor distribution. As a result, the modified regimen more significantly suppresses tumor growth in vivo than solution-based conventional MAP, suggesting that HSA-TPP NC-assisted MAP may be a promising strategy for osteosarcoma treatment.

Bisphosphonates and osteonecrosis of the jaws: Clinical and forensic aspects

OBJECTIVE

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

DESIGN

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

RESULTS

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

CONCLUSIONS

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

Enhancing the Oral Rehabilitation and Quality of Life of Bisphosphonate-Treated Patients: The Role of Dental Implants

The purpose of this review is to examine the literature on the topic of bisphosphonate-related osteonecrosis of the jaw (BRONJ) and dental implant failure in patients undergoing bisphosphonate (BP) therapy who also received dental implants before, during, or after BP treatment, as compared to healthy patients. This research followed the guidelines in the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) statement. The "PICO" or population, intervention, comparison, and outcome clinical question was as follows: does the insertion of dental implants in patients receiving bisphosphonate therapy increase the failure and loss of implants or the incidence of bisphosphonate-related osteonecrosis of the jaw compared to healthy patients? The articles published in PubMed/Medical Literature Analysis and Retrieval System Online (MEDLINE) up to July 1, 2023, were retrieved using a mix of Medical Subject Heading (MeSH) words and their entry terms. The absence of randomized clinical trials examining this issue underscores the need for additional studies with extended follow-ups to answer outstanding questions. Because of the potential for BRONJ and implant failure, patients receiving bisphosphonate medication should exercise caution when planning dental implant surgery. In addition, when such procedures are carried out, the patient's entire systemic condition must be considered.

Evaluation of trabecular bone changes according to the type of prosthesis in patients using bisphosphonates: a retrospective study

The objective of the study was to retrospectively compare the fractal size values calculated in the trabecular bone according to the type of complete removable denture, removable partial denture, and partial fixed prosthesis between patients using bisphosphonates and healthy patients, retrospectively. Panoramic radiographs of a total of 200 patients, (100 using bisphosphonates,100 control group), were taken from the right and left molar regions before and after treatment with 72 × 72 pixels. The fractal dimension (FD) was computed by using ImageJ Software using the box-counting method on the images obtained. There was an interaction effect between the trabecular bone change-patient group-the type of prosthesis used and the parameters of the area (p < 0.05). In patients using complete removable dentures and removable partial dentures in the maxilla and mandibula in the molar region, a greater decrease in FD values was observed in the control group than in the patient group using bisphosphonates. An increase in FD values over time was observed in the patient group using bisphosphonates with partial fixed maxillary and mandibular prostheses compared to the control group. Partial fixed prostheses should be preferred primarily instead of complete removable or removable partial dentures in patients using bisphosphonates to prevent osteonecrosis due to dental trauma.

A large animal model of periodontal defects in bisphosphonate-related osteonecrosis of the jaw: a comparison of clinical and radiological findings

PURPOSE

The objective of this study was to demonstrate the suitability of cone-beam computed tomography (CBCT) for in vivo research in periodontology, with implications for oral implantology, facial traumatology, and all disciplines involved in treating patients with bisphosphonate-related osteonecrosis of the jaw (BRONJ).

METHODS

Halves of the jaws of 9 Swiss mountain sheep, assigned to a control group (n=3), an osteoporosis group (n=3) and a zoledronate-exposed group (n=3), were examined. Clinical and radiological evaluations were conducted using CBCT imaging to assess whether periodontitis and bone defects were observed to a significant extent after surgical tooth extraction.

RESULTS

In contrast to the control and osteoporosis groups, the zoledronate group exhibited significant residual bone defects following tooth extraction (P<0.05). CBCT more objectively revealed these effects and enabled a numerical evaluation (in mm3).

CONCLUSIONS

Evaluating residual defects in bone blocks from sheep using CBCT analysis was found to be as effective as a clinical examination conducted by specialists in oral and maxillofacial surgery. The strong correlation between radiological findings and clinical conditions suggests that CBCT may become increasingly important in the future, particularly in periodontological research related to BRONJ.

Chronic Periodontal Infection and Not Iatrogenic Interference Is the Trigger of Medication-Related Osteonecrosis of the Jaw: Insights from a Large Animal Study (PerioBRONJ Pig Model)

Background and Objectives: Antiresorptive drugs are widely used in osteology and oncology. An important adverse effect of these drugs is medication-induced osteonecrosis of the jaw (MRONJ). There is scientific uncertainty about the underlying pathomechanism of MRONJ. A promising theory suspects infectious stimuli and local acidification with adverse effects on osteoclastic activity as crucial steps of MRONJ etiology. Clinical evidence showing a direct association between MRONJ and oral infections, such as periodontitis, without preceding surgical interventions is limited. Large animal models investigating the relationship between periodontitis and MRONJ have not been implemented. It is unclear whether the presence of infectious processes without surgical manipulation can trigger MRONJ. The following research question was formulated: is there a link between chronic oral infectious processes (periodontitis) and the occurrence of MRONJ in the absence of oral surgical procedures? Materials and Methods: A minipig large animal model for bisphosphonate-related ONJ (BRONJ) using 16 Göttingen minipigs divided into 2 groups (intervention/control) was designed and implemented. The intervention group included animals receiving i.v. bisphosphonates (zoledronate, n = 8, 0.05 mg/kg/week: ZOL group). The control group received no antiresorptive drug (n = 8: NON-ZOL group). Periodontitis lesions were induced by established procedures after 3 months of pretreatment (for the maxilla: the creation of an artificial gingival crevice and placement of a periodontal silk suture; for the mandible: the placement of a periodontal silk suture only). The outcomes were evaluated clinically and radiologically for 3 months postoperatively. After euthanasia a detailed histological evaluation was performed. Results: Periodontitis lesions could be induced successfully in all animals (both ZOL and NON-ZOL animals). MRONJ lesions of various stages developed around all periodontitis induction sites in the ZOL animals. The presence of MRONJ and periodontitis was proven clinically, radiologically and histologically. Conclusions: The results of this study provide further evidence that the infectious processes without prior dentoalveolar surgical interventions can trigger MRONJ. Therefore, iatrogenic disruption of the oral mucosa cannot be the decisive step in the pathogenesis of MRONJ.

Osteonecrosis of the jaws in patients under osteoporosis treatment: a nine-year experience report

Objective

This study aimed to report the experience of medication-related osteonecrosis of the jaws (MRONJ) in osteoporotic patients for nine years, and their associated initiating factors.

Materials and methods

The numbers of invasive oral procedures (IOP) (tooth extraction, dental implant placement, and periodontal procedures) and removable prostheses performed from January 2012 to January 2021 were obtained from the digital records of a large public dental center. There were an estimated 6,742 procedures performed in patients under osteoporosis treatment.

Results

Two cases (0.03%) of MRONJ were registered in nine years amongst patients with osteoporosis who had dental treatment at the center. From the 1,568 tooth extractions, one patient (0.06%) developed MRONJ. There was also one case from the 2,139 removable prostheses delivered (0.05%).

Conclusion

The prevalence of MRONJ associated with osteoporosis treatment was very low. The protocols adopted seem to be adequate for the prevention of this complication. The findings of this study reinforce the rare frequency of MRONJ associated with dental procedures in patients submitted to the pharmacological management of osteoporosis. An integral analysis of systemic risk factors and oral preventive strategies may be considered regularly in the dental treatment of these patients.

Risk of medication-related osteonecrosis of the jaw after dental extractions in patients receiving antiresorptive agents - A retrospective study of 240 patients

This study investigated the incidence, risk factors, and outcome of medication-related osteonecrosis of the jaw after dental extractions in patients receiving antiresorptive agents for osteoporosis or bone metastases. 240 patients with a median drug exposure of 43 months were retrospectively studied. The incidence of MRONJ after dental extraction in the osteoporosis cohort was 2.7 % per person-year (95 % CI 1.6-4.6 %) (n = 13/126), and for the bone metastases cohort 26.4 % per person-year (95 % CI 20.4-34.2 %) (n = 58/114). 92 % of MRONJ cases were stage 1. Dental infection as the reason for extraction increased the osteonecrosis risk in the osteoporosis (OR 22.77; 95 % CI 2.85-181.62; p = 0.003) and bone metastases cohorts (OR 2.72; 95 % CI 1.28-5.81; p = 0.010). Using leukocyte and platelet-rich fibrin reduced this risk by 84 % (p = 0.003), as did antibiotics use by 86-93 % (p = 0.013). Within the bone metastases cohort, an interval since last administration of at least 3 months reduced risk of MRONJ (OR 0.83; 95 % CI 0.72-0.97; p = 0.018). Mucosal healing occurred in 11/13 patients (84.6 %; 95 % CI 54.5-98.1 %) with osteoporosis and 31/58 patients (53.4 %; 95 % CI 40.0-66.7 %) with bone metastases. In conclusion, though the MRONJ risk in this selected population taking antiresorptive agents and presenting to the Oral Maxillofacial Surgery clinic for a dental extraction is considerable and higher in those with dental infections, preventive measures such as antibiotics and use of LRPF membranes may significantly reduce that risk.

Influence of bisphosphonate treatment on bone substitute performance in osteoporotic conditions

OBJECTIVE

Considering the elevated number of osteoporotic patients in need of bone graft procedures, we here evaluated the effect of alendronate (ALN) treatment on the regeneration of bone defects in osteoporotic rats. Bone formation was histologically and histomorphometrically assessed in rat femoral condyle bone defects filled with bone graft (Bio-Oss®) or left empty.

METHODS

Male Wistar rats were induced osteoporotic through orchidectomy (ORX) and SHAM-operated. The animals were divided into three groups: osteoporotic (ORX), osteoporotic treated with ALN (ORX + ALN) and healthy (SHAM). Six weeks after ORX or SHAM surgeries, bone defects were created bilaterally in femoral condyles; one defect was filled with Bio-Oss® and the other one left empty. Bone regeneration within the defects was analyzed by histology and histomorphometry after 4 and 12 weeks.

RESULTS

Histological samples showed new bone surrounding Bio-Oss® particles from week 4 onward in all three groups. At week 12, the data further showed that ALN treatment of osteoporotic animals enhanced bone formation to a 10-fold increase compared to non-treated osteoporotic control. Bio-Oss® filling of the defects promoted bone formation at both implantation periods compared to empty controls.

CONCLUSION

Our histological and histomorphometric results demonstrate that the enteral administration of alendronate under osteoporotic bone conditions leverages bone defect regeneration to a level comparable to that in healthy bone. Additionally, Bio-Oss® is an effective bone substitute, increasing bone formation, and acting as an osteoconductive scaffold guiding bone growth in both healthy and osteoporotic bone conditions.

SIGNIFICANCE

Based on the results of this study, enteral use of ALN mitigates adverse effects of an osteoporotic condition on bone defect regeneration.

Review of Osteoradionecrosis of the Jaw: Radiotherapy Modality, Technique, and Dose as Risk Factors

Radiotherapy (RT) or concurrent chemoradiotherapy (CCRT) is the cornerstone of organ-sparing or adjuvant therapy for nearly all head and neck cancers. Unfortunately, aggressive RT or CCRT can result in severe late toxicities, such as osteoradionecrosis of the jaws (ORNJ). The incidence of ORNJ is currently less than 5-6% due to advances in dental preventive care programs, RT planning systems, and RT techniques. Although numerous patient-, tumor-, and treatment-related factors may influence the incidence rates of ORNJ, RT modality (equipment), technique, and dose-volume-related factors are three of the most influential factors. This is mainly because different RT equipment and techniques have different levels of success at delivering the prescribed dose to the focal volume of the treatment while keeping the "organ at risk" safe. ORNJ risk is ultimately determined by mandibular dose, despite the RT technique and method being known predictors. Regardless of the photon delivery method, the radiobiological effects will be identical if the total dose, dose per fraction, and dose distribution within the tissue remain constant. Therefore, contemporary RT procedures mitigate this risk by reducing mandibular dosages rather than altering the ionizing radiation behavior in irradiated tissues. In light of the paucity of studies that have examined the impact of RT modality, technique, and dose-volume-related parameters, as well as their radiobiological bases, the present review aims to provide a comprehensive overview of the published literature on these specific issues to establish a common language among related disciplines and provide a more reliable comparison of research results.

Effects of a locally administered risedronate/autogenous bone graft combination on bone healing in a critical-size rabbit defect model

BACKGROUND

Risedronate is a bisphosphonate with poor oral absorption. An extremely hydrophilic molecule that has a high affinity for bone, risedronate also inhibits the farnesyl diphosphate synthase enzyme, inhibiting osteoclastic activity and reducing bone turnover and resorption. Autogenous bone grafts contain osteogenic cells and osteoinductive factors that are essential for bone regeneration and are therefore considered the gold standard. Thus, this study aimed to investigate the impact of local risedronate administered with autogenous bone grafts on the healing of defects in rabbit skulls using histological, histomorphometric, immunohistochemical, and three-dimensional radiological methods.

METHODS

Two 10-mm-diameter critical-size defects were created in 16 rabbits and filled with autogenous bone graft and autogenous bone graft + 5 mg risedronate in the control (C) and risedronate (RIS) groups, respectively. Residual graft, new bone, soft tissue areas, and bone volume were evaluated in the 4- and 8-week study groups.

RESULTS

There were no statistically significant differences in bone graft, new bone, or soft tissue area between the groups at 4 weeks (p > 0.05). At 8 weeks, the new bone area was significantly higher in the RIS group than in the C group (p < 0.05). The h scores obtained from sialoprotein and osteopontin did not differ significantly between the groups (p > 0.05). The radiologically measured total bone volume was significantly higher in the RIS group than in the C group at both time points (p < 0.05).

CONCLUSIONS

In this study, risedronate enhanced the osteoconductive properties of autogenous bone grafts and rapidly created better-quality bone. This could improve future patient outcomes.

Practical Considerations for the Clinical Application of Bone Turnover Markers in Osteoporosis

Bone turnover markers (BTMs) are released during the bone remodelling cycle and are measurable in blood or urine, reflecting bone remodelling rate. They have been useful in elucidating the pharmacodynamics and effectiveness of osteoporosis medication in clinical trials and are increasingly used in routine clinical management of osteoporosis, especially for monitoring therapy, in addition to their use in other metabolic bone disease such as Paget's disease of bone and osteomalacia. Serum β isomerised C-terminal telopeptide of type I collagen and pro-collagen I N-terminal propeptide have been designated as reference BTMs for use in osteoporosis. In addition, bone-specific isoenzyme of alkaline phosphatase (B-ALP) secreted by osteoblasts and tartrate-resistant acid phosphatase 5b (TRACP-5b) secreted by osteoclasts are also found to be specific markers of bone formation and resorption, respectively. The concentrations of the latter enzymes in blood measured by immunoassay provide reliable measures of bone turnover even in the presence of renal failure. B-ALP is recommended for use in the assessment of renal bone disease of chronic kidney disease, and TRACP-5b shows promise as a marker of bone resorption in that condition. BTMs in blood do not suffer from biological variation to the same extent as the older BTMs that were measured in urine. Appropriate patient preparation and sample handling are important in obtaining accurate measures of BTMs for clinical use. Reference change values and treatment targets have been determined for the reference BTMs for their use in monitoring osteoporosis treatment. Further ongoing studies will enhance their clinical applications.

Medication-Related Osteonecrosis of the Jaw: A Cross-Sectional Survey among Urologists in Switzerland, Germany, and Austria

Medication-related osteonecrosis of the jaw (MRONJ) is a potentially preventable adverse side effect of mainly antiresorptive drugs. MRONJ is expected to become a growing clinical problem due to the aging population and the increasing number of patients requiring antiresorptive agents. Knowledge and awareness about MRONJ and elimination of the oral and dental risk factors before starting antiresorptive therapy (AR) are fundamental to reducing the incidence of MRONJ. In urology, ARs are used primarily in patients suffering from bone metastases due to prostate cancer and to prevent cancer-treatment-induced bone loss (CTIBL) in prostate cancer patients receiving endocrine therapy. This postal survey aimed to evaluate disease-related knowledge and awareness about implementing oral examinations for patients starting AR among Swiss, German, and Austrian urologists. A total of 176 urologists returned the completed questionnaire, yielding a response rate of 11.7%. Of the respondents, 44.9% (n = 79) and 24.4% (n = 43) stated that they give more than five first-time prescriptions of denosumab and of intravenous or oral bisphosphonates per year, respectively. Only 14.8% (n = 26) of the participating urologists had never encountered MRONJ cases related to BPs. Of the participants, 89.8% (n = 158) had implemented referrals to dentists for oral examination before initiating AR. The mean percentage of correct answers regarding the knowledge about MRONJ was 70.9% ± 11.2%. In contrast to previous surveys on MRONJ among physicians, this study showed that the participating urologists were sufficiently informed about MRONJ, as reflected by the high number of participants implementing preventive dental screenings.

The effect of drug holiday on preventing medication-related osteonecrosis of the jaw in osteoporotic rat model

Background

Medication-related osteonecrosis of the jaw (MRONJ) is a severe complication associated with antiresorptive medications managing osteoporosis, such as bisphosphonates (BPs). To date, there is very limited evidence from prospective, controlled studies to support or refute the controversial prevention regimen that if a discontinuation of BPs before dentoalveolar surgery, so called "drug holiday", is effective in reducing the risk of MRONJ development in patients with osteoporosis. We proposed an experimental animal study, aiming to investigate the prevention of MRONJ following tooth extractions in osteoporotic condition, with the implementation of a BP drug holiday.

Methods

Twenty rats were subjected to bilateral ovariectomy. After establishing the osteoporotic condition, all rats were exposed to weekly injections of zoledronate acid (ZA) for 8 weeks. After ZA treatment, 10 rats were subjected to dental extraction and defined as control group, and the rest 10 rats assigned to the DH group had a drug holiday of 8 weeks prior to dental extraction. Eight weeks after the dentoalveolar surgery, bone turnover biomarker in serum, occurrence of MRONJ-like lesion and histomorphometric assessment of osteonecrosis in mandible, and bone microarchitecture indices in femur, were examined.

Results

Eight weeks after dental extraction, the DH group showed a recovered osteoclastic activity, indicated by significantly increased number of osteoclasts in the mandibles and serum level of C-terminal telopeptides of type I collagen, as compared to the control group. No significant differences were observed in the gross-view and histological occurrences of MRONJ-like lesions between the two groups.There was no significant difference in bone microarchitecture in the femur between the control and DH groups before ZA therapy and 8 weeks after dental extraction.

Conclusion

Our data provided the first experimental evidence in the osteoporotic animal model that the implementation of a BP holiday in prior to dental extractions could partially recover osteoclastic activity, but could not alleviate the development of MRONJ-like lesion or exacerbate the osteoporotic condition in the femur. Longer-term drug holiday, or combination of drug holiday and other prophylaxes to prevent MRONJ in patients with osteoporosis could be worth exploring in future studies, to pave the way for clinical managements.

The translational potential of this article

This in vivo prospective study reported that a recovery of osteoclastic activity by a BP drug holiday for 8 weeks in osteoporosis rats did not alleviate the development of MRONJ-like lesion followed by dental extractions. It contributes to the understanding of regimens to prevent MRONJ.

Significance of medication discontinuation on bisphosphonate-related jaw osteonecrosis in a rat model

Bisphosphonate (BP) discontinuation has been advised as a measure to prevent the incidence of bisphosphonate-related osteonecrosis of the jaw (BRONJ), however, its efficacy remains controversial. This study aimed to analyze the efficacy of BP discontinuation in reducing BRONJ severity following tooth extraction in a rat model. Thirty-four male Sprague-Dawley rats were divided into two BRONJ model categories: oral administration (PO) of alendronate (1 mg/kg) for 3 and 8 weeks and intraperitoneal (IP) injection of pamidronate (3 mg/kg) and dexamethasone (1 mg/kg) for 20 days. The PO model was divided into five groups (a control group without BPs and four experimental groups with 1-week discontinuation). The IP model was divided into two groups consisting of group I (without discontinuation) and group II (1-week discontinuation). One molar from both sides of the mandible was extracted. After extraction, the PO models were sacrificed at 3 and 5 weeks, and the IP models were sacrificed either immediately or at 2, 4, 6, and 8 weeks. Micro-CT showed non-significant differences among PO groups but significant differences were observed between IP groups. Most bone remodeling parameters within group I of the IP model differed significantly (p-value < 0.05). Histologically, group I showed a significantly higher percentage of necrotic bone than group II (51.93 ± 12.75%, p < 0.05) and a higher number of detached osteoclasts in TRAP staining. With discontinuation of medication for at least 1 week in rats, the effects of BPs on alveolar bone are suppressed and bone turnover and osteoclast functions are restored.

Efficacy of Adjunctive Photobiomodulation in the Management of Medication-Related Osteonecrosis of the Jaw: A Systematic Review

Background: Medication-related osteonecrosis of the jaw (MRONJ) is a severe adverse medication response that manifests as progressive bone necrosis in the craniofacial area. There is still no clear treatment protocol for the management of MRONJ. The purpose of this study was to conduct a systematic review to assess the efficacy of photobiomodulation (PBM) as an adjunct to MRONJ therapy. Methods: In line with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement, a literature search was performed on PubMed/MEDLINE, Scopus, Web of Science, and Cochrane databases. Two examiners examined eligibility and risk of bias separately before extracting data. Results: Two hundred sixty-nine articles were found through electronic search, out of which only 11 met the inclusion criteria and were included in qualitative synthesis (9 retrospectives, 1 prospective, and 1 case series). A total number of 759 patients and a mean age ranging from 54 to 74 years were reviewed. Females were the most frequent gender in all of the selected studies (72% females to 28% males), and the most frequent stage in the studies mentioned above was stage II (66%). Most of the studies had shown a significant improvement when PBM was used as an adjunctive treatment. Conclusions: Based on the results of this study, PBM as an adjuvant therapy can significantly improve the outcomes of each treatment plan. However, surgical intervention for the complete healing of the lesions is suggested.

The Role of Bone Grafts in Preventing Medication-Related Osteonecrosis of the Jaw: Histomorphometric, Immunohistochemical, and Clinical Evaluation in Animal Model

Objective

To evaluate the effects of inorganic bovine bone graft (Lumina Bone, Criteria, Brazil) and beta-tricalcium phosphate (β-TCP) graft (ChronOS, Synthes, Brazil) in rats with the risk of developing post-extraction medication-related osteonecrosis of the jaw (MRONJ).

Methods

Eighteen male Wistar rats weighing 350 to 450 g were induced to develop MRONJ using zoledronic acid for 5 weeks. In the sixth week, the right maxillary first molar was extracted. The animals in Group I (G1) did not receive bone grafts after tooth extraction, while Group II (G2) animals received inorganic bovine bone grafts, and Group III (G3) animals received beta-tricalcium phosphate (β-TCP) grafts. Clinical evaluation and histomorphometric and immunohistochemical analyses were performed. ANOVA and Tukey's statistical tests were used and a level of significance was considered to be 5%.

Results

In the clinical evaluation, animals from G2 and G3 did not present clinical manifestations of osteonecrosis, unlike the control group (G1) animals, which presented necrotic bone tissue exposure in all samples. In the histomorphometric evaluation, animals in G3 showed greater formation of bone tissue (66%) and less formation of bone lacuna (18%) than animals in G1 (58%/32%) and in G2 (59%/27%) (P < 0.05). Moderate (++) immunostaining was observed in G2 and G3 for RANKL, TRAP, and OC, while G1 showed moderate (++) labeling for OC and mild (+) immunostaining for TRAP and RANKL.

Conclusions

Greater formation of bone tissue and fewer bone lacunae were found in animals treated with β-TCP. In clinical evaluation, bone graft groups presented with the clinical manifestation of MRONJ and showed higher intensity of immunostaining for TRAP and RANKL. Despite the limitations of experimental animal studies, the results of this work may assist in the development of future clinical research for the prevention of MRONJ.

The "Phoenix Jaw" Phenomenon Revisited: Two Cases of Bisphosphonate-Related Mandible Osteonecrosis Surgically Treated with Complete Bone Regeneration

Bisphosphonate-related osteonecrosis of the jaws represents a well-recognized complication occurring in patients being administered drugs for the treatment of osteoporosis and/or malignant disease. Treatment of this condition, aiming to alleviate the symptoms and restore functional status, represents a challenge for the maxillofacial surgeon. Conservative management has been proposed for early stages of this condition, while surgical intervention is mandatory for advanced disease. Two cases of severe bisphosphonate-related osteonecrosis of the jaw that achieved complete osseous recontouring after partial mandibulectomy, are presented.

Current use of bone turnover markers in the management of osteoporosis

The adult bone is continuously being remodelled to repair microdamage, preserve bone strength and mechanical competence as well as maintain calcium homeostasis. Bone turnover markers are products of osteoblasts (bone formation markers) and osteoclasts (bone resorption markers) providing a dynamic assessment of remodelling (turnover). Resorption-specific bone turnover markers are typically degradation products of bone collagen molecules (N- [NTX] and C-telopeptide cross-linked type 1 collagen [CTX]), which are released into the circulation and excreted in urine; or enzymatic activities reflecting osteoclastic resorption, tartrate-resistant acid phosphatase [TRACP]. Formation-specific bone turnover markers embrace different osteoblastic activities: type 1 collagen synthesis (Procollagen type I N- propeptide [PINP]), osteoblast enzymes (bone-specific alkaline phosphatase [BALP]), or bone matrix proteins [osteocalcin]. Among individuals not receiving osteoporosis treatment, resorption and formation markers are tightly linked and highly correlated (r= 0.6-0.8). Significant biological variability was reported in the past, but these issues have been greatly improved with automated assays and attention to pre-analytical and analytical factors that are known to influence bone turnover marker levels. Bone turnover markers are not useful in the diagnosis of osteoporosis, the individual prediction of bone loss, fracture, or rare complications, or in the selection of pharmacological treatment. Despite remaining issues with reference intervals and assays harmonization, bone turnover markers have proven to be useful in elucidating the pharmacodynamics and effectiveness of osteoporosis medications in clinical trials. As an alternative to BMD testing, BTMs may be useful to monitor osteoporosis therapies.

Changes in the Dentition of Small Dogs up to 4 Months of Age

Simple Summary

National and EU legislation impose age restrictions for the rabies vaccination which is required in the export of dogs. This makes it important to know whether a particular dog is older than three months or not. In veterinary practice, age estimation is mostly based on dentition, although there is no standardized method described in the literature for determining the age of dogs under four months old and we found considerable variation in the references. We observed and recorded the changes in cranial shape and dentition of two Yorkshire Terriers born by caesarean section on 2 March 2018 up to four months of age. At the age of three months, both individuals showed the same characteristics of a wide gap between the upper maxillary incisors (i2 and i3) and the lower maxillary incisor and canine (i3 and c).

Abstract

It is common practice in EU member states to permit the entry of dogs vaccinated against rabies at the age of at least 3 months. In the absence of easily applicable comparative data, subjective disputes emerge around age. The aim of our study was to observe the development of dog teeth. During birth, an abnormally lying Yorkshire Terrier fetus was stuck in the birth canal, which led to a caesarean section, hence, the exact date of birth was known. For the next 4 months, two puppies were examined weekly, and they showed the same development. The dogs were born without teeth. At the age of 4.5 weeks, the canines I appeared, together with the adjacent incisors (i3), and the second incisor (i2) also erupted at the age of 6 weeks. A week later, a first incisor (i1) also appeared. From the age of 2.5 months, the distance between the teeth was increasing, especially on the upper dental arch. At 3.5 months of age, only the bottom front incisors (i1) had not grown in a row, and the significant distance between the top incisors, comparable to the width of the tooth, was striking. Since only two dogs of one breed were involved in this case study, the observations cannot be generalized.

Medication-Related Osteonecrosis of the Jaw in Dental Practice: A Retrospective Analysis of Data from the Milan Cohort

A retrospective analysis was performed with the aim of understanding whether the risk factors showed in the literature for medication-related osteonecrosis of the jaws (MRONJ) in cancer patients are also relevant in osteoporotic patients taking antiresorptive drugs (ARDs). Data were retrospectively pooled from health records of patients on ARDs who requested a dental visit between January 2006 and April 2020 in the Dental Unit at Fondazione Ca’ Granda IRCCS Ospedale Maggiore Policlinico, University of Milan. A total of 434 patients were included. The following variables were collected: sex, age, smoking habit, type of ARD, duration of treatment, route of administration, therapeutic indication, concurrent systemic therapies and pathologies. Statistical analysis confirmed the relevance of chemotherapy, smoking, and immunosuppressive drugs as risk factors. In addition, a higher frequency of MRONJ in osteoporotic patients was reported in our cohort in association with an immunodeficiency disorder of variable origin. In conclusion, the identification of individual risk-profile before dental treatments is crucial for prevention. Anamnesis should include main risk factors, such as immunosuppression, dental extractions, smoking, trauma, and poor dental health. Nevertheless, our suggestion for dental professionals is to conduct a complete medical history of patients who mention long-term per oral therapies with ARDs for osteoporosis. Osteoporotic, as well as cancer patients, may also benefit from periodic monitoring of the ARDs therapy in order to prevent MRONJ.

Oral Complications in Cancer Patients–Medication-Related Osteonecrosis of the Jaw (MRONJ)

Medication-Related Osteonecrosis of the Jaw (MRONJ) was first reported in 2003. Despite the progress in the understanding of this oral complication in cancer patients for the past 18 years, there is still discussion about the best way to define MRONJ, prevent the complication, how to diagnose, and the options of treatment available. The initial reports associated MRONJ to bisphosphonates and denosumab, medications that work as bone-modifying agents. Later, other agents such as the antiangiogenics, have also been reported to cause the oral complication, either alone or in combination with antiresorptives. Initially, these medications were prescribed to patients with osteoporosis and cancers patients with bone metastasis. Today, because of the effect of the medications in the bone remodeling system, patients with several other diseases such as giant cell tumors, rheumatoid arthritis, Paget's disease of bone, fibrous dysplasia, osteogenesis imperfecta, are managed with these medications, significantly increasing the population of individuals at risk for developing MRONJ. This mini review focused on the cancer patient. It updates the dental clinician on the recent scientific literature about MRONJ and provides information on how to diagnose and manage patients being treated with these medications, suggests protocols to prevent the development of MRONJ, and present ways to manage those patients who develop the oral complication.

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

CONTEXT

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Medication-related osteonecrosis of the jaw after tooth extraction in patients receiving pharmaceutical treatment for osteoporosis: A retrospective cohort study

Background/purpose

Bone resorption inhibitors, such as bisphosphonates (BPs) and anti-receptor activator of nuclear factor kappa B ligand antibodies (denosumab; Dmab), are used to treat osteoporosis and effectively reduce the risk of fracture. However, medication-related osteonecrosis of the jaw (MRONJ) has been reported as a rare adverse effect. Invasive tooth extraction procedures are reportedly a factor in the development of MRONJ. In this study, we aimed to retrospectively observe and clinically examine the effect of medication status on MRONJ development after tooth extraction in patients receiving drug treatment for osteoporosis.

Materials and methods

This study was conducted among patients who visited our hospital between December 2015 and December 2021. We collected and analyzed the medical information of patients who underwent dental extractions while using osteoporosis medications, including oral and injectable BPs and Dmab.

Results

Among antiresorptive medication users, 40 patients (70 teeth) underwent extraction. The mean duration of BP/Dmab use was 40.4 months, and the mean duration of drug holiday was 6.9 months. MRONJ after tooth extraction was not seen in BP users, but we observed two cases in Dmab users. A significant difference in MRONJ development was confirmed with the use of injectable compared with oral medication administration (odds ratio＝5.01).

Conclusion

The use of injectable bone resorption inhibitors was associated with a higher risk of developing MRONJ. The route of administration, duration of medication, and withdrawal period should be carefully considered to prevent MRONJ after tooth extraction.

Serum biomarkers for bisphosphonate-related osteonecrosis of the jaw: a prospective clinical study

In this prospective study, serum levels of 12 possible biomarkers were compared between osteonecrosis of the jaw (ONJ) and control groups, before and after dentoalveolar surgery. The results suggest that patients with abnormal serum levels of specific biomarkers should be monitored closely for the prevention and early diagnosis of ONJ.

INTRODUCTION

Bisphosphonate-related osteonecrosis of the jaw (ONJ) is an adverse effect of long-term bisphosphonate therapy. This study aimed to identify bone biomarkers for ONJ risk assessment and diagnosis.

METHODS

This prospective study included patients with histories of bisphosphonate therapy without current ONJ who were in need of dentoalveolar surgery of the jaw area. Serum levels of 12 possible bone markers, selected based on their involvement in ONJ pathogenesis, were compared between ONJ and control groups before dentoalveolar surgery (T0), at 8 postoperative weeks (T1), and at 4 months after diagnosis(T2).

RESULTS

Seventy-six patients who met the inclusion criteria were included in the study; 33 were assigned to the ONJ group, and 43 patients without ONJ signs or symptoms after dentoalveolar surgery were assigned to the control group. In the ONJ group, at both T0 and T1, the mean tartrate-resistant acid phosphatase isoform 5b (TRACP 5b) levels were significantly lower and the mean Dickkopf-related protein 1 (DKK1) levels were significantly higher than the corresponding values for the control group. Linear mixed model analysis revealed significant group effects over time for serum TRACP 5b and DKK1 after adjusting for demographic, pharmacological, and diagnostic variables. Lower serum levels of TRACP 5b under a specified cut-off value (≤ 2.899 U/L) at T0 indicated a 20.40-fold increased risk of ONJ development.

CONCLUSION

Patients with abnormally low serum levels of TRACP 5b and high serum levels of DKK1 should be monitored closely before and after dentoalveolar surgery for the prevention and early diagnosis of ONJ.

Medication-Related Osteonecrosis of the Jaw (MRONJ): A Review of Pathophysiology, Risk Factors, Preventive Measures and Treatment Strategies

Medication-related osteonecrosis of the jaw (MRONJ) is a major problem that can occur in people taking certain medications such bisphosphonates and denosumab. It can be used to treat osteoporosis or cancer. Bisphosphonate exposure, dental diseases and procedures, age, sex, anatomical factors, medical issues, and hereditary factors are all variables that enhance the risk of MRONJ. Even though MRONJ and antiresorptive medications have a close association, the pathophysiology of MRONJ is unknown. Careful dental preparation and oral hygiene instructions significantly minimize the risk of osteonecrosis of the jaw (ONJ). It is ideal to start antiresorptive treatment after the completion of required dental treatment; it is not contraindicated and carries low risk in patients who are on oral antiresorptive medications for less than three years. Drug holidays are one proposed solution to address MRONJ. However, there is still inadequate evidence to support their effectiveness. The objectives of this literature review are to recognize the main diagnostic principles and risk factors and to review the pathophysiology, protective procedures and treatment modalities related to MRONJ.

The following topics are covered in the review: epidemiology, diagnostic criteria, risk factors, pathogenesis and mechanism, MRONJ staging and symptoms, clinical and radiographic findings, treatment strategies, prevention and drug holiday.

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

Antiresorptives are the most widely prescribed drugs for the treatment of osteoporosis. They are also used in malignant bone metastases, multiple myeloma, and Paget's disease, and provide therapeutic efficacy on those diseases. However, it was reported that the occurrence of osteonecrosis of the jaw (ONJ) could be related to antiresorptive exposures, and there have been many cases regarding this issue. Therefore, a clearer definition and treatment guidelines were needed for this disease. The American Society for Bone and Mineral Research and the Amnerican Association of Oral and Maxillofacial Surgeons reported statements on bisphosphonate-related ONJ (BRONJ), and a revised version was recently presented. In the revised edition, the diagnosis BRONJ was changed to medication-related ONJ (MRONJ), which reflects consideration of the fact that ONJ also occurs for denosumab, a bone resorption inhibitor of the receptor activator of the nuclear factor-κB ligand antibody family, and bevacizumab, an anti-angiogenesis inhibitor. The Korean Society for Bone and Mineral Research and the Korean Association of Oral and Maxillofacial Surgeons had collectively formed a task force for the preparation of an official statement on MRONJ based on a previous position paper in 2015. The task force reviewed current knowledge and coordinated dental and medical opinions to propose the guideline customized for the local Korean situation.

Alveolar socket healing in 5-lipoxygenase knockout aged female mice treated or not with high dose of zoledronic acid

This study investigated the role 5-lypoxigenase (5-LO) on alveolar socket healing in aged female mice treated with zoledronic acid (ZL). Forty 129/Sv female mice (64–68 weeks old), 20 wild type (WT) and 20 5-LO knockout (5LOKO) were equally distributed according to ZL treatment: WT Control, WT ZL, 5LOKO Control, and 5LOKO ZL. ZL groups were treated with an intraperitoneal injection of 250 µg/Kg of ZL, while controls were treated with saline. Treatments were administered once a week, starting four weeks before surgery for tooth extraction and until 7 and 21 days post-surgery. Mice were euthanized for a comprehensive microscopic analysis (microCT, histomorphometry and immunohistochemistry). WT ZL mice presented intense inflammatory infiltrate (7 days), delayed bone formation (21 days), reduced collagenous matrix quality, and a deficiency in Runx-2 + , TRAP + , and macrophages as compared to controls. 5LOKO ZL animals presented decreased number of Runx-2 + cells in comparison to 5LOKO Control at 7 days, but no major changes in bone healing as compared to WT or 5LOKO mice at 21 days. The knockout of 5LO favored intramembranous bone healing in aged female mice, with a direct impact on inflammatory response and bone metabolism on the development of ONJ-like lesions.

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

PURPOSE

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSION

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

Comparison of the Effect of Oral Versus Intravenous Bisphosphonate Administration on Osteoclastogenesis in Advanced-Stage Medication-Related Osteonecrosis of the Jaw Patients

It is yet unknown whether the intravenous administration route alone can fully account for the exacerbation of medication-related osteonecrosis of the jaw (MRONJ). The purpose of this retrospective study was to identify the potential role of the bisphosphonate (BP) administration route as an independent prognostic factor for non-cancerous, stage III MRONJ patients. Bone samples were retrospectively obtained from two groups of osteoporosis patients who underwent surgery for the treatment of stage III MRONJ. Among the subjects, 10 had a history of only oral BP consumption and 10 of intravenous (IV) BP administration. The samples were assessed for osteoclast morphology and immunohistochemical expression of the receptor activator of NF-κB ligand (RANKL), osteoprotegerin (OPG), and potassium calcium-activated channel subfamily N member 4 (Kcnn4). Although the osteoclasts derived from both groups exhibited no significant differences in the mean quantity, diameter, and nuclearity, significantly attenuated tartrate-resistant acid phosphatase activity was noted among the IV BP-induced MRONJ bones compared to those of the oral BP group. Significant suppression of the RANKL/OPG ratio and Kcnn4 expression among the retrieved bones of IV BP group patients was also noted. Our results indicate the potential of the BP administration route as an independent prognostic factor for advanced-stage MRONJ, regardless of the dosage or indication for which the BP was prescribed.

Bone turnover markers can predict healing time in medication-related osteonecrosis of the jaw

Objectives

Medication-related osteonecrosis of the jaw (MRONJ) is a severe and difficult-to-treat adverse event of bone-modifying agents. Therefore predictive strategies determining patients at risk for a prolonged healing duration are needed to optimize treatment. Thus, the present study evaluates whether or not bone turnover markers can be used to predict the healing duration in MRONJ patients.

Materials and methods

The present study is a retrospective data analysis of patients suffering from MRONJ and positive histology for Actinomyces spp., who were identified at the General Hospital Vienna from 2014 to 2018. During the first visit, the patients’ demographics and levels of bone formation parameters were compiled. Healing times were analysed by Cox regression in dependence on these factors.

Results

A total of 52 patients were identified who fulfilled the inclusion criteria. The indication for bone-modifying agents was breast cancer (n = 21), prostate cancer (n = 14), multiple myeloma (n = 6) and other malignant diseases (n = 11). In 43 (82.7%) of our patients, we were able to document complete mucosal healing. Furthermore, patients who responded faster to therapy showed higher levels of C-telopeptide (P < 0.05), osteocalcin (P < 0.05) and bone-specific alkaline phosphatase (P < 0.05), but lower levels of 1.25-dihydroxyvitamin D (P < 0.05) than slower responding patients. No correlation was found regarding parathyroid hormone or calcitonin levels. Interestingly, patients who had a slower response were less likely to report dental procedures, but more likely to report a history of chemotherapy.

Conclusion

CTX and osteocalcin levels may be used for predicting healing duration for MRONJ.

Inflammasomes in Alveolar Bone Loss

Bone remodeling is tightly controlled by osteoclast-mediated bone resorption and osteoblast-mediated bone formation. Fine tuning of the osteoclast-osteoblast balance results in strict synchronization of bone resorption and formation, which maintains structural integrity and bone tissue homeostasis; in contrast, dysregulated bone remodeling may cause pathological osteolysis, in which inflammation plays a vital role in promoting bone destruction. The alveolar bone presents high turnover rate, complex associations with the tooth and periodontium, and susceptibility to oral pathogenic insults and mechanical stress, which enhance its complexity in host defense and bone remodeling. Alveolar bone loss is also involved in systemic bone destruction and is affected by medication or systemic pathological factors. Therefore, it is essential to investigate the osteoimmunological mechanisms involved in the dysregulation of alveolar bone remodeling. The inflammasome is a supramolecular protein complex assembled in response to pattern recognition receptors and damage-associated molecular patterns, leading to the maturation and secretion of pro-inflammatory cytokines and activation of inflammatory responses. Pyroptosis downstream of inflammasome activation also facilitates the clearance of intracellular pathogens and irritants. However, inadequate or excessive activity of the inflammasome may allow for persistent infection and infection spreading or uncontrolled destruction of the alveolar bone, as commonly observed in periodontitis, periapical periodontitis, peri-implantitis, orthodontic tooth movement, medication-related osteonecrosis of the jaw, nonsterile or sterile osteomyelitis of the jaw, and osteoporosis. In this review, we present a framework for understanding the role and mechanism of canonical and noncanonical inflammasomes in the pathogenesis and development of etiologically diverse diseases associated with alveolar bone loss. Inappropriate inflammasome activation may drive alveolar osteolysis by regulating cellular players, including osteoclasts, osteoblasts, osteocytes, periodontal ligament cells, macrophages, monocytes, neutrophils, and adaptive immune cells, such as T helper 17 cells, causing increased osteoclast activity, decreased osteoblast activity, and enhanced periodontium inflammation by creating a pro-inflammatory milieu in a context- and cell type-dependent manner. We also discuss promising therapeutic strategies targeting inappropriate inflammasome activity in the treatment of alveolar bone loss. Novel strategies for inhibiting inflammasome signaling may facilitate the development of versatile drugs that carefully balance the beneficial contributions of inflammasomes to host defense.

Mechanism, prevention, and treatment for medication-related osteonecrosis of the jaws

The morbidity rate of medication-related osteonecrosis of the jaws (MRONJ) increased rapidly in recent years. Thusfar, the mechanism of MRONJ has no consensus. The possible mechanisms may include bone remodeling inhibition theory, angiogenesis inhibition theory, oral microorganism infection theory, immunosuppression theory, cytotoxicity-targeted oral epithelial cells, microcrack formation of maxillary or mandibular bone, and single nucleotide polymorphism. However, the efficacy of prevention and treatment based on a single mechanism is not ideal. Routine oral examination before MRONJ-related drug treatment, treatment of related dental diseases, and regular oral follow-up during drug treatment are of great significance for the prevention of MRONJ. During the treatment of MRONJ, the stage of MRONJ must be determined accurately, treatment must be standardized in accordance with the guidelines, and personalized adjustments must be made considering the specific conditions of patients. This review aimed to combine the latest research and guidelines for MRONJ and the experiences on the treatment of MRONJ in the Maxillofacial Surgery Department of West China Hospital of Stomatology, Sichuan University, and discuss the strategies to improve the clinical process.

Prevention and treatment of oral adverse effects of antiresorptive medications for osteoporosis - A position paper of the Brazilian Society of Endocrinology and Metabolism (SBEM), Brazilian Society of Stomatology and Oral Pathology (Sobep), and Brazilian Association for Bone Evaluation and Osteometabolism (Abrasso)

Antiresorptive therapy is the main form of prevention of osteoporotic or fragility fractures. Medication-related osteonecrosis of the jaw (MRONJ) is a relatively rare but severe adverse reaction to antiresorptive and antiangiogenic drugs. Physicians and dentists caring for patients taking these drugs and requiring invasive procedures face a difficult decision because of the potential risk of MRONJ. The aim of this study was to discuss the risk factors for the development of MRONJ and prevention of this complication in patients with osteoporosis taking antiresorptive drugs and requiring invasive dental treatment. For this goal, a task force with representatives from three professional associations was appointed to review the pertinent literature and discuss systemic and local risk factors, prevention of MRONJ in patients with osteoporosis, and management of established MRONJ. Although scarce evidence links the use of antiresorptive agents in the context of osteoporosis to the development of MRONJ, these agents are considered a risk factor for this complication. Despite the rare reports of MRONJ in patients with osteoporosis, the severity of symptoms and impact of MRONJ in the patients' quality of life make it imperative for health care professionals to consider this complication when planning invasive dental procedures.

Comparison of Vascular Morphometry in Jawbones and Long Bones: Micro-CT Study in a Rat Model Treated with Zoledronic Acid

The study was aimed at investigating the effect of zoledronic acid on vascular morphometry in jawbones and long bones on a rat model. Twenty-four 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 the surgical procedures, ZA or saline treatment was continued until sacrifice at week 2, week 4, and week 8 postoperatively. Vascular perfusion with MICROFIL was performed on all the animals. Micro-CT analysis demonstrated a tendency of decreased vessel density and vessel number in ZA-treated groups but no statistical difference. In conclusion, the neovessel formation is suppressed but not significantly by ZA treatment, indicating that angiogenesis inhibition may contribute to the development of MRONJ but does not play a key role.

Anti-VEGFR therapy is one of the healing inhibitors of antiresorptive-related osteonecrosis of the jaw

INTRODUCTION

Antiresorptive-related osteonecrosis of the jaw (ARONJ) is a rare but serious adverse event associated with bone-modifying agents (BMAs) and affects patients in the terminal stages of cancer. Molecular targeting drugs (MTDs), anti-vascular endothelial growth factor receptor (VEGFR), and anti-epidermal growth factor receptor (EGFR) drugs are essential in various cancer treatments, although MTDs are risk factors for ARONJ. However, the mechanism through which MTDs affect treatment prognosis of ARONJ remains unclear. Therefore, we investigated the potential inhibitory factors for healing in the conservative therapy of ARONJ with a focus on MTDs.

MATERIALS AND METHODS

Sixty patients who were administered BMAs for the treatment of malignancies and who underwent conservative treatment for ARONJ were assessed. The healing rate of ARONJ for each risk factor was retrospectively evaluated.

RESULTS

Among the 60 patients, 27 were male and 33 were female. The median age was 67 years, and the median follow-up period was 292 (range 91-1758) days. The healing rate was lower in those treated with both zoledronic acid (Za) and denosumab (Dmab) than in those treated with Za or Dmab alone (0% vs. 28.8%, p = 0.03). Regarding the administration of MTDs, the treatment rate with anti-VEGFR drugs was 7.1% (p = 0.04), anti-EGFR drugs was 12.5% (p = 0.18), and without MTDs was 36.8%.

CONCLUSION

In the conservative treatment of ARONJ, the administration of several BMAs and anti-VEGFR drugs was the factor contributing to the inhibition of healing.

Dental pathologies in tumor patients with bone metastases or multiple myeloma scheduled for antiresorptive therapy

Background: Medication-related osteonecrosis of the jaw (MRONJ) is a potentially severe complication of mainly antiresorptive drugs. We evaluated the frequency of dentoalveolar pathologies in patients scheduled for antiresorptive therapy in a 'real-world' setting, also including patients with poor oral health potentially requiring tooth extractions and/or other dentoalveolar surgery. This approach is in contrast to the setting of recent randomized trials with restrictive exclusion criteria. Patients & methods: We prospectively included patients suffering from solid tumors with osseous metastases or multiple myeloma. Screening for dentoalveolar pathologies was done prior to initiation of antiresorptive therapy at the specialized MRONJ clinic of the University Hospital for Cranio-Maxillofacial and Oral Surgery, Innsbruck, Austria. Results: 119 subjects could be included. In 76 patients (63.9%), a dental focus was revealed including deep caries (24.4% of patients), chronic apical periodontitis (26.9%), periodontal disease (45.8%), root remnants (16%), jaw cysts (2.5%), partially impacted teeth (5.0%) and peri-implantitis (5.0%). Conclusion: Considering the high number of dentoalveolar pathologies (63.9%), systematic dental focus screening prior to initiation of antiresorptive therapy is of utmost importance to lower the risk for MRONJ.

Tocilizumab: Another medication related to osteonecrosis of the jaws? A case report and literature review

Introduction: Medication-related osteonecrosis of the jaw (MRONJ) is a serious complication in patients receiving antiresorptive medication, such as bisphosphonates and denosumab, for different oncologic and non-oncologic diseases. Here, we report a case of MRONJ in a patient treated with tocilizumab, a humanized anti-interleukin-6 receptor antibody that effectively treats moderate to severe rheumatoid arthritis in adults.

Case description: A 45-year-old female patient diagnosed with severe rheumatoid arthritis, who had been undergoing intravenous tocilizumab therapy for three years without history of bisphosphonate use, was referred to our department. Four weeks previously, several teeth in the maxilla and mandible were removed under local anesthesia by her dentist. Two weeks after the extractions, she felt pain in both jaws. We diagnosed wound dehiscence and delayed healing of the alveolar bone after the tooth extractions. Digital volume tomography showed persistent dry alveolar sockets. The patient underwent surgical debridement of necrotic bone, and intravenous antibiotics were administered in hospital. Five months later, wound dehiscence reoccurred in the same regions. Histopathological analysis of bone biopsies revealed a diagnosis of MRONJ. Four months later, wound dehiscence occurred in the left maxillary alveolar ridge, and local bone resection was performed under antibiotic treatment. Twenty-four months after the last surgery, wound dehiscence had healed completely without signs of recurrence.

Discussion: Osteomyelitis of the jaw in patients treated with tocilizumab has not been reported often. This case confirms the potential role of this interleukin-6 receptor inhibitor in the pathogenesis of MRONJ and shows that patients who receive tocilizumab with MRONJ-like symptoms should be closely monitored. The pathomechanism of MRONJ under tocilizumab therapy remains unclear, so dental practitioners, maxillofacial surgeons, and rheumatologists should look for signs of MRONJ in patients receiving tocilizumab to prevent MRONJ onset.

Schemes for Drug-Induced Treatment of Osteonecrosis of Jaws with Particular Emphasis on the Influence of Vitamin D on Therapeutic Effects

Drugs that inhibit bone resorption are prescribed most often by orthopedists, hematologists, or oncologists. Dental practice rarely draws attention to their importance and the effects they carry. The problem concerns mainly older people owing to oncological problems or postmenopausal consequences, but everyone can be at risk. Carefully conducted interviews and analysis of history and disease should always be performed before any action is taken by patients taking this type of medicine. Further action should consider possible complications and, above all, the risk of their occurrence. In this article, the most important issues related to the treatment of drug-induced osteonecrosis of the jaws (ONJ) are raised, including medication-related osteonecrosis of the jaw (MRONJ); conservative treatment, including the use of laser; and the impact of vitamin D supplementation on the overall treatment, prognosis, and prevention before complication, which is osteonecrosis of the jaw in the course of treatment with bisphosphonates and other drugs predisposing to MRONJ, such as denosumab and angiogenesis inhibitors. The degree of osteonecrosis is also critical, as it is possible to avoid surgical procedures for only conservative methods that sometimes bring good results. Surgical treatment of advanced stages is complicated and carries a high risk of error and complications. MRONJ is a disease that is easy to avoid, but it is difficult to treat and treatment sometimes leads only to a partial remission of the disease, not a complete cure.

Emerging therapies with potential risks of medicine-related osteonecrosis of the jaw: a review of the literature

In the past, osteonecrosis of the jaw (ONJ) was generally reported with bisphosphonate drugs; hence, the term BRONJ (bisphosphonate-related osteonecrosis of the jaw) was initially proposed. This was followed by the term ARONJ (antiresorptive osteonecrosis of the jaw). More recently, other novel medications such as vascular endothelial growth factor (VEGF) inhibitors, tyrosine kinase inhibitors and humanised antibodies that affect osteoclastic action have been reported to initiate ONJ in several cases. For this reason, in 2014, the American Association of Oral and Maxillofacial Surgeons (AAOMS) changed the term to MRONJ - medication-related osteonecrosis of the jaw. The review primarily focuses on ONJ associated with emerging therapies for the management of bone disorders. This article sheds some light on the risk factors that predispose dental patients to the development of osteonecrosis, the mechanisms of drug therapies associated with MRONJ, and potential treatment and management regimes for MRONJ patients. The current review noted that the incidence and associated risk of MRONJ is significant with the new therapeutic agents discussed. Therefore, for optimised patient care, pharmacovigilance with the new medications is essential for dental professionals.

Quantitative Segmentation Analysis of the Radiological Changes by Using ITK-SNAP: Risk Assessment of the Severity and Recurrence of Medication-related Osteonecrosis of the Jaw

Background and purpose: Medication-related osteonecrosis of the jaw (MRONJ) severely impairs patients' quality of life and is remarkably refractory to treatment. There are lots of studies about identification of the radiographic features of MRONJ, yet reports about quantitative radiographic analysis for the risk assessment of the severity and recurrence of MRONJ are rarely heard. The aim of this study was to investigate the volumes of osteolytic lesions and radiodensity values of osteosclerotic lesions in MRONJ patients by using ITK-SNAP for severity prediction and prognosis evaluation. Materials and methods: Of 78 MRONJ patients (78 lesions) involved in this retrospective study, 53 were presented as osteolytic lesions and 25 were presented as osteosclerotic changes alone. Comprehensive CBCT images, demographics and clinical data of patients were investigated. The volumetric analysis and radiodensity measurement were performed by ITK-SNAP. SPSS 25.0 were used for statistical analysis. Results: The osteolytic lesion volumes in MRONJ patients receiving intravenous bisphosphonates (P=0.004) and patients without osteoporosis (P=0.027) were significantly large. No significant correlation between the volumes and bisphosphonates duration was found (P=0.094). The radiodensity values of osteosclerotic lesions was significantly correlated with bisphosphonates duration (P=0.040). The surrounding area of post-surgical lesions in MRONJ patients with recurrence showed significantly great radiodensity values (P=0.025). No significant correlation between the radiodensity values and the transformation from osteosclerotic lesions to osteolytic lesions was observed (P=0.507). Conclusion: MRONJ patients receiving intravenous bisphosphonates develop into large volumes of osteolytic lesions more easily. Long-term bisphosphonates duration is possibly related with higher bone density of osteosclerotic lesions, while higher density is not associated with the transformation from osteosclerotic lesions to osteolytic lesions. A rise of bone mineral density nearby post-surgical lesions is probably a predictor for MRONJ recurrence.