Bisphosphonates and osteonecrosis of the jaw: cause and effect or a post hoc fallacy?

P7C3 Ameliorates Bone Loss by Inhibiting Osteoclast Differentiation and Promoting Osteogenesis

Bone homeostasis, the equilibrium between bone resorption and formation, is essential for maintaining healthy bone tissue in adult humans. Disruptions of this process can lead to pathological conditions such as osteoporosis. Dual-targeted agents, capable of inhibiting excessive bone resorption and stimulating bone formation, are being explored as a promising strategy for developing new treatments to address osteoporosis. In this study, we investigated the effects of P7C3 on bone remodeling and its potential therapeutic role in osteoporosis treatment in mice. Specifically, P7C3 can remarkably suppress receptor activator of nuclear factor-κB (NF-κB) ligand (RANKL)-induced osteoclast differentiation in bone marrow macrophages via the Akt-NF-κB-NFATc1 signaling pathway. Additionally, RNA sequencing (RNAseq) analysis revealed that P7C3 promoted osteoblast differentiation and function through the Wnt/β-catenin signaling pathway, thereby enhancing bone formation. Furthermore, μCT analysis and histological examination of bone tissues from P7C3-treated mice showed attenuation of both Ti-induced bone erosion and ovariectomy (OVX)-induced bone loss. These findings suggest that P7C3 may have a novel function in bone remodeling and may be a promising therapeutic agent for the treatment of osteoporosis. © 2023 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

Osteoporosis, bisphosphonates, and ocular inflammation

BACKGROUND

Osteoporosis, as a musculoskeletal disease, is very common, especially in the era of aging society. It is described by a reduction in bone strength and increased risk of fractures, which are linked to considerable morbidity, mortality, and high healthcare burdens. Bisphosphonates are the most commonly used drugs to manage osteoporosis and they consequently reduce fracture risk. However, one of the clinical challenges is fear of side effects in patients who are using bisphosphonates as the administration of these drugs is lengthy. Ocular inflammation has been reporting as one of the potential vision-threatening side effects of bisphosphonates.

PURPOSE

To review previously reported ocular inflammation in patients taking bisphosphonates.

METHOD

A literature survey was conducted using databases in order to collect data for a narrative review of published reports regarding ocular side effects of bisphosphonates.

RESULTS

People taking bisphosphonates were at a relatively low risk of ocular inflammation, with the onset from a few hours after exposure up to more than 3 years. The release of inflammatory mediators mainly by activated gamma delta T cells in response to bisphosphonates was the main cause of ocular inflammation.

CONCLUSION

Strategies for treating patients with osteoporosis should consider the potential ocular side effects of bisphosphonates. Ocular inflammation, as one of the side effects of bisphosphonates, is a serious sight-threatening sign and should be taken seriously. Greater awareness of the association between bisphosphonate use and ocular inflammation may allow for earlier identification and timely treatment of future cases.

Recent Progresses in the Treatment of Osteoporosis

Osteoporosis (OP) is a chronic bone disease characterized by aberrant microstructure and macrostructure of bone, leading to reduced bone mass and increased risk of fragile fractures. Anti-resorptive drugs, especially, bisphosphonates, are currently the treatment of choice in most developing countries. However, they do have limitations and adverse effects, which, to some extent, helped the development of anabolic drugs such as teriparatide and romosozumab. In patients with high or very high risk for fracture, sequential or combined therapies may be considered with the initial drugs being anabolic agents. Great endeavors have been made to find next generation drugs with maximal efficacy and minimal toxicity, and improved understanding of the role of different signaling pathways and their crosstalk in the pathogenesis of OP may help achieve this goal. Our review focused on recent progress with regards to the drug development by modification of Wnt pathway, while other pathways/molecules were also discussed briefly. In addition, new observations made in recent years in bone biology were summarized and discussed for the treatment of OP.

Retrospective longitudinal study of osteoporosis in adults with recessive dystrophic epidermolysis bullosa

This retrospective study looks at bone mineral density of people with recessive dystrophic epidermolysis bullosa as assessed by dual-energy x-ray absorptiometry. Data were collected in 34 patients aged 16-35 years. Statistical analysis showed immobility, low body mass index, and pubertal delay was associated with osteoporosis.

Current Understanding of the Pathophysiology of Osteonecrosis of the Jaw

PURPOSE OF REVIEW

Osteonecrosis of the jaw (ONJ) is a rare and severe necrotic bone disease reflecting a compromise in the body's osseous healing mechanisms and unique to the craniofacial region. Antiresorptive and antiangiogenic medications have been suggested to be associated with the occurrence of ONJ; yet, the pathophysiology of this disease has not been fully elucidated. This article raises the current theories underlying the pathophysiology of ONJ.

RECENT FINDINGS

The proposed mechanisms highlight the unique localization of ONJ. The evidence-based mechanisms of ONJ pathogenesis include disturbed bone remodeling, inflammation or infection, altered immunity, soft tissue toxicity, and angiogenesis inhibition. The role of dental infections and the oral microbiome is central to ONJ, and systemic conditions such as rheumatoid arthritis and diabetes mellitus contribute through their impact on immune resiliency. Current experimental studies on mechanisms of ONJ are summarized. The definitive pathophysiology is as yet unclear. Recent studies are beginning to clarify the relative importance of the proposed mechanisms. A better understanding of osteoimmunology and the relationship of angiogenesis to the development of ONJ is needed along with detailed studies of the impact of drug holidays on the clinical condition of ONJ.

A systematic review and economic evaluation of bisphosphonates for the prevention of fragility fractures

BACKGROUND

Fragility fractures are fractures that result from mechanical forces that would not ordinarily result in fracture.

OBJECTIVES

To evaluate the clinical effectiveness and safety of bisphosphonates [alendronic acid (Fosamax^® and Fosamax^® Once Weekly, Merck Sharp & Dohme Ltd), risedronic acid (Actonel^® and Actonel Once a Week^®, Warner Chilcott UK Ltd), ibandronic acid (Bonviva^®, Roche Products Ltd) and zoledronic acid (Aclasta^®, Novartis Pharmaceuticals UK Ltd)] for the prevention of fragility fracture and to assess their cost-effectiveness at varying levels of fracture risk.

DATA SOURCES

For the clinical effectiveness review, six electronic databases and two trial registries were searched: MEDLINE, EMBASE, The Cochrane Library, Cumulative Index to Nursing and Allied Health Literature, Web of Science and BIOSIS Previews, Clinicaltrials.gov and World Health Organization International Clinical Trials Registry Platform. Searches were limited by date from 2008 until September 2014.

REVIEW METHODS

A systematic review and network meta-analysis (NMA) of effectiveness studies were conducted. A review of published economic analyses was undertaken and a de novo health economic model was constructed. Discrete event simulation was used to estimate lifetime costs and quality-adjusted life-years (QALYs) for each bisphosphonate treatment strategy and a strategy of no treatment for a simulated cohort of patients with heterogeneous characteristics. The model was populated with effectiveness evidence from the systematic review and NMA. All other parameters were estimated from published sources. A NHS and Personal Social Services perspective was taken, and costs and benefits were discounted at 3.5% per annum. Fracture risk was estimated from patient characteristics using the QFracture^® (QFracture-2012 open source revision 38, Clinrisk Ltd, Leeds, UK) and FRAX^® (web version 3.9, University of Sheffield, Sheffield, UK) tools. The relationship between fracture risk and incremental net benefit (INB) was estimated using non-parametric regression. Probabilistic sensitivity analysis (PSA) and scenario analyses were used to assess uncertainty.

RESULTS

Forty-six randomised controlled trials (RCTs) were included in the clinical effectiveness systematic review, with 27 RCTs providing data for the fracture NMA and 35 RCTs providing data for the femoral neck bone mineral density (BMD) NMA. All treatments had beneficial effects on fractures versus placebo, with hazard ratios varying from 0.41 to 0.92 depending on treatment and fracture type. The effects on vertebral fractures and percentage change in BMD were statistically significant for all treatments. There was no evidence of a difference in effect on fractures between bisphosphonates. A statistically significant difference in the incidence of influenza-like symptoms was identified from the RCTs for zoledronic acid compared with placebo. Reviews of observational studies suggest that upper gastrointestinal symptoms are frequently reported in the first month of oral bisphosphonate treatment, but pooled analyses of placebo-controlled trials found no statistically significant difference. A strategy of no treatment was estimated to have the maximum INB for patients with a 10-year QFracture risk under 1.5%, whereas oral bisphosphonates provided maximum INB at higher levels of risk. However, the PSA suggested that there is considerable uncertainty regarding whether or not no treatment is the optimal strategy until the QFracture score is around 5.5%. In the model using FRAX, the mean INBs were positive for all oral bisphosphonate treatments across all risk categories. Intravenous bisphosphonates were estimated to have lower INBs than oral bisphosphonates across all levels of fracture risk when estimated using either QFracture or FRAX.

LIMITATIONS

We assumed that all treatment strategies are viable alternatives across the whole population.

CONCLUSIONS

Bisphosphonates are effective in preventing fragility fractures. However, the benefit-to-risk ratio in the lowest-risk patients may be debatable given the low absolute QALY gains and the potential for adverse events. We plan to extend the analysis to include non-bisphosphonate therapies.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42013006883.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Skeletal Site-specific Effects of Zoledronate on in vivo Bone Remodeling and in vitro BMSCs Osteogenic Activity

Bisphosphonate-related osteonecrosis of the jaw (BRONJ) has been associated with long-term oral or intravenous administration of nitrogen-containing bisphosphonates (BPs). However, the pathogenesis of BRONJ remains unknown, and definitively effective treatment has not yet been established. Bisphosphonate-related osteonecrosis (BRON) tends to occur in maxillofacial bones. Why this occurs is still unclear. Here we show that zoledronate (Zol) treatment suppresses alveolar bone remodeling after tooth typical clinical and radiographic hallmarks of the human BRONJ, whereas enhances peripheral bone quantity in bone remodeling following injury in the same individuals, shown as increased cortical bone thickness, increased trabecular bone formation and accelerated bone defect repair. We find that the RANKL/OPG ratio and Wnt-3a expression are suppressed at the extracted alveolar sites in Zol-treated rats compared with those at the injured sites of peripheral bones. We also show that Zol-treated bone marrow stromal cell (BMSCs) derived from jaw and peripheral bones exhibit differences in cell proliferation, alkaline phosphatase (ALP) activity, expression of osteogenic and chondrogenic related marker genes, and in vivo bone formation capacity. Hopefully, this study will help us better understand the pathogenesis of BRONJ, and deepen the theoretical research.

Design and methods for a Scandinavian pharmacovigilance study of osteonecrosis of the jaw and serious infections among cancer patients treated with antiresorptive agents for the prevention of skeletal-related events

Objective

Osteonecrosis of the jaw (ONJ) is a recognized complication of potent antiresorptive therapies, especially at the doses indicated to prevent skeletal complications for cancer patients with bone metastases. This paper describes the rationale and methods for a prospective, post-authorization safety study of cancer patients treated with antiresorptive therapies.

Methods

As part of a comprehensive pharmacovigilance plan, developed with regulators’ input, the study will estimate incidence of ONJ and of serious infections among adult cancer patients with bone metastases treated with denosumab (120 mg subcutaneously) or zoledronic acid (4 mg intravenously, adjusted for renal function). Patients will be identified using routinely collected data combined with medical chart review in Denmark, Sweden, and Norway. Followup will extend from the first administration of antiresorptive treatment to the earliest of death, loss-to-follow-up, or 5 years after therapy initiation. Results will be reported for three treatment cohorts: denosumab-naïve patients, zoledronic acid-naïve patients, and patients who switch from bisphosphonate treatment to denosumab. ONJ cases will be identified in three newly established national ONJ databases and adjudicated by the committee that functioned during the XGEVA^® clinical trials program.

Conclusion

This study will provide a real world counterpart to the clinical trial-estimated risks for ONJ and serious infections for cancer patients initiating denosumab or zoledronic acid. The establishment of ONJ databases in the three Scandinavian countries will have potential benefits outside this study for the elucidation of ONJ risk factors and the evaluation of ONJ treatment strategies.

Pathophysiology of Osteonecrosis of the Jaws

Osteonecrosis of the jaw (ONJ) is a multifactorial disease in patients with primary or metastatic bone malignancy or osteoporosis undergoing systemic antiresorptive therapy, where pathophysiology has not yet been fully determined. The staging of ONJ is based on severity of symptoms and extent of clinical and radiographic findings. Treatment strategies range from conservative local wound care to aggressive resective surgery of all necrotic bone. The first ONJ cases were reported in 2003 and 2004, and although significant progress has been made in our understanding of the disease, much more work needs to be done to completely explain its pathophysiology.

Impact of bisphosphonate-related osteonecrosis of the jaw on osteoporotic patients after dental extraction: a population-based cohort study

Background and Aims

Little is currently known about the risk of developing bisphosphonate-related osteonecrosis of the jaw (BRONJ). This study sought to determine the incidence of BRONJ in osteoporotic patients. We also sought to identify the nature and types of risk factors of osteonecrosis of jaw (ONJ) related to the use of oral bisphosphonates (BPs).

Materials and Methods

Data from the National Health Insurance system of Taiwan. This cohort study included 19,399 adult osteoporosis patients received dental extraction in 2000-2010 (osteoporosis cohort) and 38,669 age and gender matched comparisons selected from dental extraction people without osteoporosis and osteonecrosis history (comparison cohort). All study subjects were followed from the date of their dental extraction (index date) to the development of ONJ and were included in the study up to 2011 or were lost to the study, whichever occurred first. Cox proportional hazard regression was used to estimate the hazard ratio and 95% confidence intervals for the two cohorts.

Results

Patients with osteoporosis had a significantly higher risk to develop ONJ than healthy persons (adjusted HR, 2.05; 95% confidence interval, 1.58–2.65). The risk of ONJ increased with the severity of osteoporosis, no matter whether patient with cancer or not. A cumulative effect of dental extraction frequency may increase the risk of ONJ.

Conclusions

We concluded that ONJ is caused by a number of factors. Osteoporosis and past dental history play the very important roles, while BPs play the synergistic effect.

Development of oral osteomucosal tissue constructs in vitro and localization of fluorescently-labeled bisphosphonates to hard and soft tissue

Bisphosphonates (BPs) are anti-resorptive agents commonly used to treat bone-related diseases; however, soft tissue-related side-effects are frequently reported in some BP users, such as oral or gastrointestinal (GI) ulcerations. BPs are stable analogs of pyrophosphate and have high affinity to hydroxyapatite, allowing them to bind to the bone surfaces and exert suppressive effects on osteoclast functions. However, the underlying mechanisms as to how bone-seeking BPs also exert cytotoxic effects on soft tissue remain unknown. In the present study, we investigated the localization of nitrogen-containing BPs (N-BPs) in hard and soft tissue using fluorescently-labeled N-BPs in vitro. We developed osteomucosal tissue constructs in vitro to recapitulate the hard and soft tissue of the oral cavity. A histological examination of the osteomucosal tissue constructs revealed a differentiated epithelium over the bone containing osteocytes and the periosteum, similar to that observed in the rat palatal tissues. Following treatment with the fluorescently-labeled bisphosphonate, AF647-ZOL, the osteomucosal constructs exhibited fluorescent signals, not only in the bone, but also in the epithelium. No fluorescent signals were observed from the control- or ZOL-treated constructs, as expected. Collectively, the data from the present study suggest that N-BPs localize to epithelial tissue and that such a localization and subsequent toxicity of N-BPs may be associated, at least in part, with soft tissue-related side-effects.

Bisphosphonate-related osteonecrosis of the jaw: a review of the literature

Bisphosphonates (BPs) are a class of drugs used to treat osteoporosis and malignant bone metastasis. BPs show high binding capacity to the bone matrix, especially in sites of active bone metabolism. The American Society for Bone and Mineral Research defines BRONJ as “an area of exposed bone in the maxillofacial region that has not healed within 8 weeks after identification by a healthcare provider in a patient who is receiving or has been exposed to a bisphosphonate and has not had radiation therapy to the craniofacial region.” Bisphosphonate-related osteonecrosis of the jaw (BRONJ) can adversely affect quality of life, as it may produce significant morbidity. The American Association of Oral and Maxillofacial Surgeons (AAOMS) considers as vitally important that information on BRONJ be disseminated to other dental and medical specialties. The purpose of this work is to offer a perspective on how dentists should manage patients on BPs, to show the benefits of accurately diagnosing BRONJ, and to present diagnostic aids and treatments strategies for the condition.

Antiresorptive drug-related osteonecrosis of the jaw

Nitrogen-containing and non-nitrogen-containing bisphosphonates have been implicated in the development of osteonecrosis of the jaw (ONJ), a condition termed bisphosphonate-related OHJ. Other antiresorptive drugs have been implicated in the development of OHJ, hence the new term antiresorptive drug-related ONJ. The underlying pathogenesis remains unclear, and no definite diagnosis or cure has been established for this debilitating condition. This article reviews some of the most common antiresorptive drugs with their associated risks of ONJ and the current understanding of the pathogenesis ONJ, and summarizes current clinical guidelines.

Efficacy of pamidronate in children with low bone mineral density during and after chemotherapy for acute lymphoblastic leukemia and non-Hodgkin lymphoma

Background

Reduced bone mineral density (BMD) is a significant sequelae in children receiving chemotherapy for acute lymphoblastic leukemia (ALL) and non-Hodgkin lymphoma (NHL). Reduced BMD is associated with an increased risk for fractures. Pamidronate, a second-generation bisphosphonate, has been used to treat osteoporosis in children. This study evaluated the safety and efficacy of pamidronate in children with low BMD during and after chemotherapy for ALL and NHL.

Methods

Between April 2007 and October 2011, 24 children with ALL and NHL were treated with pamidronate. The indication was a decreased BMD Z-score less than -2.0 or bone pain with a BMD Z-score less than 0. Pamidronate was infused at 1 mg/kg/day for 3 days at 1-4 month intervals (pamidronate group, cases). The BMD Z-scores of the cases were compared with those of 10 untreated patients (control group). Lumbar spine BMDs were measured every 6 cycles using dual energy X-ray absorptiometry and Z-scores were calculated. Bone turnover parameters (25-hydroxyvitamin D, alkaline phosphatase, parathyroid hormone, osteocalcin, and type I collagen c-terminal telopeptide) were analyzed.

Results

The median cycle of pamidronate treatment was 12. Increases in BMD Z-scores were significantly higher in the pamidronate group than in the control group (P<0.001). BMD (mg/cm²) increased in all pamidronate-treated cases. Twenty patients who complained of bone pain reported pain relief after therapy. The treatment was well tolerated.

Conclusion

Pamidronate appears to be safe and effective for the treatment of children with low BMD during and after chemotherapy for ALL and NHL.

Tooth extraction in osteoporotic patients taking oral bisphosphonates

This prospective study compares two different surgical protocols with different degrees of invasiveness for tooth extraction in patients treated with oral bisphosphonates (BPs). No intraoperative complications were observed in either of the two groups, and there was no evidence of postoperative bisphosphonate-associated osteonecrosis of the jaw in any of the extractions in the study group at follow-up (1,480 extractions). According to our data, dental extraction seems to be safe in osteoporotic patients treated with oral bisphosphonates.

INTRODUCTION

Oral bisphosphonates are drugs commonly prescribed for the treatment of osteoporosis and other resorptive bone diseases. Since 2003, there have been numerous publications relating bisphosphonate-related osteonecrosis of the jaw (BRONJ) in patients using oral bisphosphonates, such as alendronate and risedronate. Most of the BRONJ cases reported in literature show a strong correlation with dental pathologies, dental extractions, and/or oral surgical procedures.

METHODS

This study was conducted on 700 consecutive patients treated with oral bisphosphonates who underwent dental extractions. A total of 1,480 extractions were involved: 864 in the mandible and 616 in the maxilla. The patients were assigned randomly to one of two groups: 334 were treated with delicate surgery and closure by primary intention (Protocol A), and the other 366 were treated with nontraumatic avulsion and closure by secondary intention (Protocol B). All patients were administered with antibiotics coverage.

RESULTS

Seven hundred patients with required removal of compromised teeth were included in the study. No intraoperative complications were observed in either of the two groups, and there was no evidence of postoperative bisphosphonate-associated osteonecrosis of the jaw in any of the extractions in the study group at follow-up (1,480 extractions).

CONCLUSIONS

The findings of this prospective study indicate that both suggested protocols for tooth extraction in patients treated with oral BPs can provide a predictable treatment outcome (100 % success). Therefore, because atraumatic surgery is more comfortable for patients, we suggest the adoption of Protocol B, which limits trauma to both the soft and hard tissues.

Does dental and oral health influence the development and course of bisphosphonate-related osteonecrosis of the jaws (BRONJ)?

PURPOSE

The main causes for the occurrence of bisphosphonate-related osteonecrosis of the jaws (BRONJ) are the application of aminobisphosphonates and the extraction of teeth. However, the question which factors in dental and oral health are relevant has not been answered completely.

MATERIALS AND METHODS

In a retrospective study, 50 patients who were treated with BRONJ between 2000 and 2009 were analyzed. As underlying diseases, they suffered from breast cancer (n = 24), multiple myeloma (n = 16), prostate cancer (n = 5), osteoporosis (n = 4), and kidney cancer (n = 1). The data were collected from the patient charts of the treating dentists, oral and maxillofacial surgeons, general practitioners, and oncologists. The time of occurrence of BRONJ after treatment onset with bisphosphonates (BP) was examined with Kaplan-Meier estimator and logrank test (level of significance 0.05).

RESULTS

At the time of BP treatment, onset the decayed, missing, and filled teeth (DMFT) index was 20.5 ± 4.2. Patients with a DMFT value less than 20 showed a significantly longer BRONJ-free time interval after BP treatment onset with 39.7 ± 1.1 months compared to patients with a DMFT value higher than 20, in whom BRONJ appeared after 14.4 ± 2.8 months (p < 0.001). However, the DMFT value had no influence on the success rate of BRONJ treatment. As a pre-existing oral disease, 60 % of the patients (n = 30) had marginal periodontitis; 38 % (n = 19), apical periodontitis; and 22 % (n = 11), a pressure lesion from their dentures. In patients with marginal periodontitis, BRONJ occurred after 26.3 months (range 20.9-31.3) and in patients without marginal periodontitis, after 27.4 months (range 14.6-40.1) (p = 0.58). Only 20 % of the patients with marginal periodontitis received adequate treatment. Without parodontal treatment, BRONJ occurred 15 months earlier compared to patients with parodontal treatment (p = 0.12). The state of the periodontium did not influence the healing rate of BRONJ (p > 0.999).

CONCLUSION

The present study highlights the great benefit of good dental and oral health in the prevention of BRONJ; but it also shows that after the appearance of BRONJ, these factors do no longer seem to play a relevant role in the disease course.

Equilibrium-dependent bisphosphonate interaction with crystalline bone mineral explains anti-resorptive pharmacokinetics and prevalence of osteonecrosis of the jaw in rats

Bisphosphonates (BPs) are chemically stable analogs of pyrophosphate exhibiting strong affinity to bone and have been used for the treatment of diseases characterized by excessive bone resorption. Contrary to the widely accepted BP accumulation model in bone after repeated applications, we report here that an equilibrium-dependent BP-crystalline bone mineral interaction may better explain BP bio-distribution and anti-catabolic bone remodeling and may be relevant to the appearance of osteonecrosis of the jaw (ONJ) in rats. Fluorescent-labeled BP analogs were synthesized and used to evaluate the mode of bone adsorption. After fluorescent-labeled BP adsorbed on crystalline calcium phosphates in vitro, subsequent BP application replaced the previously absorbed BP depending on the dose and the relative binding affinity to hydroxyapatite. The in vivo intravenous zoledronate (ZOL) injection of repeated fractional doses resulted in lower serum CTX and TRAP5b measurements than a single bolus injection in spite of the equivalent cumulative dose. Repeated injections resulted in the distribution of fluorescent-labeled BP on the large area of bone surfaces; whereas the single bolus injection gave rise to the intense BP bio-distribution at selected bone sites such as the alveolar process of jawbones. Necrotic maxillary alveolar bone was predominantly observed in vitamin D deficiency rats treated with bolus ZOL injection. The palatal necrotic bone was characteristically sequestrated by the fistulation of hyperplastic oral epithelium, suggesting the initial development of ONJ-like lesions in rats. Our results suggest that equilibrium-dependent BP-bone interaction may, in part, determine the effectiveness and influence side effects of long-term and repeated applications of BPs.

Principles of oral surgery for prevention of bisphosphonate-related osteonecrosis of the jaw

OBJECTIVES

Principles and workflow are described to prevent bisphosphonate-related osteonecrosis of the jaw (BRONJ) when oral surgery is necessary in patients taking bisphosphonates.

MATERIAL AND METHOD

A total of 117 surgical procedures were performed on 68 patients taking bisphosphonates. The basis of the treatment was (1) use of perioperative antibiotics; (2) after dentoalveolar surgical procedures, bone edges were smoothed and mucoperiosteal flaps were prepared to ensure tension-free wound closure; (3) sutures were not removed until 14 days postsurgery; (4) long-term results were evaluated.

RESULTS

Ninety-seven percent of all procedures were simple and showed no complications. Only 3 patients with a long history of intravenous bisphosphonate medication developed BRONJ within 4 weeks after surgery. No patient receiving oral bisphosphonates developed BRONJ. No long-term failure was observed when primary wound healing was successful.

CONCLUSIONS

The high success rate of the described surgical procedures imply dentoalveolar surgery with low risk of development of BRONJ is possible for patients taking bisphosphonates.

A case of autoimmune hepatitis and bisphosphonate-related osteonecrosis of the jaw

Autoimmune hepatitis (AIH) is a chronic inflammatory liver disease of unknown aetiology usually requiring long-term immunosuppressive therapy. We present the case of an AIH patient who received long-term corticosteroids and azathioprine. As treatment for concomitant osteoporosis she was also treated with potent intravenous bisphosphonate (BP). This treatment was complicated by the development of BP-related osteonecrosis of the jaw (BRONJ). BRONJ is an uncommon complication of BP treatment regimes that occurs at increased frequency in the presence of other risk factors, including chronic inflammatory conditions. Our patient suffered from a severe and complicated clinical course of BRONJ which, despite adequate therapy, resulted in death of the patient. Here we discuss the risk factors for the development and clinical course of BRONJ in AIH and the implications for management of these patients.

Bisphosphonate-related osteonecrosis of the jaws--a review

The aim was to evaluate the knowledge about bisphosphonate-related osteonecrosis of the jaws (BRONJ). A bibliographic search in Medline, PubMed and the Cochrane Register of controlled clinical trials was performed between 2003 and 2010 by using the terms bisphosphonate and osteonecrosis of the jaw. The amount of publications per year, the type of journal for publication, and the evidence level of the trial were evaluated. Next to this the incidences and the success of treatment strategies for BRONJ were identified. A total of 671 publications were reviewed. Since 2006 more than 100 publications on BRONJ per year (with an upward trend) have been published, mostly in dental journals. The evidence level could be determined for 176 publications and only one grade Ia study was found. The studies showed a wide variety in design, most of them being retrospective. The incidence of BRONJ is strongly dependent on oral or intravenous application and varies between 0.0% and 27.5%. There is no scientific data to sufficiently support any specific treatment protocol for the management of BRONJ. Further clinical studies are needed to evaluate the incidence and treatment strategies at a higher level of evidence. Therefore uniform study protocols would be favourable.

Tooth extraction in patients on zoledronic acid therapy

OBJECTIVES

Surgical management of patients following zoledronic acid therapy is particularly difficult, since the dental extraction is the main cause of BRONJ.

METHODS

A case-control study was conducted on 176 patients treated with intravenous (IV) bisphosphonates for oncologic pathologies who also underwent dental extractions. The study was divided randomly into two groups: 91 were treated with Plasma Rich in Growth Factor Plasma (PRGF) (study group) and the other 85 were not treated with the growth factor preparation (control group).

RESULTS

Panoramic X-ray and computed tomography were performed both before and 60 months after surgery. By clinical and radiological diagnosis, BRONJ was diagnosed in only 5 patients in the control group at an average of 91, 6 days after tooth extraction.

CONCLUSIONS

We hypothesize that Plasma Rich in Growth Factor (PRGF) is important for the successful treatment of patients on bisphosphonates to restore the osteoblast/osteoclast homeostatic cycles via autologous cytokines. Moreover, this protocol reduces the risk of BRONJ when it is necessary to perform dental extractions in patients undergoing IV bisphosphonate treatment.

Osteoporosis in paediatric patients with spina bifida

The prevalence and morbidity associated with osteoporosis and fractures in patients with spina bifida (SB) highlight the importance of osteoporosis prevention and treatment in early childhood; however, the issue has received little attention. The method for the selection of appropriate patients for drug treatment has not been clarified.

OBJECTIVE

To review the literature concerning fracture risks and low bone density in paediatric patients with SB. We looked for studies describing state-of-the-art treatments and for prevention of secondary osteoporosis.

METHODS

Articles were identified through a search in the electronic database (PUBMED) supplemented with reviews of the reference lists of selected papers. The main outcome measures were incidence of fractures and risk factors for fracture, an association between bone mineral density (BMD) and occurrence of fracture, risk factors of low BMD, and effects of pharmacological and non-pharmacological treatments on BMD and on the incidence of fractures. We considered as a secondary outcome the occurrence of fractures in relation to the mechanism of injury.

RESULTS

Results indicated that patients with SB are at increased risk for fractures and low BMD. Risk factors that may predispose patients to fractures include higher levels of neurological involvement, non-ambulatory status, physical inactivity, hypercalciuria, higher body fat levels, contractures, and a previous spontaneous fracture. Limitations were observed in the number and quality of studies concerning osteoporosis prevention and treatment in paediatric patients with SB. The safety and efficiency of drugs to treat osteoporosis in adults have not been evaluated satisfactorily in children with SB.

Bisphosphonates and oral health: primer and an update for the practicing surgeon

Oral and intravenous bisphosphonates have been in clinical use for two decades for the treatment of patients with malignancy, osteoporosis, and other diseases affecting bone metabolism. The purpose of this article is to review the features of these drugs, their effect on the diseases they treat, the oral findings associated with their use, and the assessment of osteonecrosis incidence, pathophysiology, with some insights into treatment.

Potential pathophysiological mechanisms in osteonecrosis of the jaw

Bisphosphonates are used in the treatment of hypercalcemia of malignancy, skeletal complications associated with metastastic bone disease, Paget's disease, and osteoporosis. Osteonecrosis of the jaw (ONJ) is a recently described clinical condition that has been associated with the use of nitrogen-containing bisphosphonates. Reports describing this entity first appeared in the literature in 2003. While there have been significant numbers of case reports and a limited number of retrospective and prospective studies examining risk factors associated with ONJ, the pathophysiology of this condition remains elusive. In this review, we explore proposed mechanisms underlying ONJ development and identify potential areas for future investigation.

Bisphosphonates induce senescence in normal human oral keratinocytes

Bisphosphonate-related osteonecrosis of the jaw (BRONJ) commonly occurs in individuals receiving bisphosphonates (BPs) with clinical manifestations of the exposed necrotic bone. Although defective wound healing of soft tissue is frequently, if not always, observed in BRONJ, the effects of BPs on oral soft tissue or cells remain unknown. To investigate the effects of BPs on cells of oral mucosal tissue, we studied the effect of pamidronate (PAM), one of the BPs most commonly administered to cancer patients, on the phenotypes of normal human oral keratinocytes (NHOK) and fibroblasts (NHOF). When exposed to PAM at 10 µM, NHOK, not NHOF, underwent senescence: NHOK overexpressed senescence-associated β-galactosidase (SA-β-Gal), p16INK4A, IL-6, and IL-8. When exposed to a higher level (50 µM) of PAM, NHOK maintained senescent phenotypes, but NHOF underwent apoptosis. PAM-induced senescence in NHOK is mediated, in part, via geranylgeranylation of the mevalonate pathway. Our in vitro 3D oral mucosal tissue construction studies further demonstrated that PAM induced senescence and impaired re-epithelialization of oral mucosa. Analysis of these data indicates that premature senescence of oral mucosal cells and subsequent defective soft-tissue wound healing might be partly responsible for the development of BRONJ in individuals receiving PAM or other BPs.

Multiple myeloma and bisphosphonate-related osteonecrosis of the mandible associated with dental implants

Multiple myeloma (MM) is a malignant plasma cell disorder and more than 30% of patients with this pathology develop osteolytic lesions in the jaw. Either pamidronate or zoledronic acid is recommended in patients with MM who have one or more lytic lesions. However, bisphosphonate-related osteonecrosis of the jaws (BRONJ) has been described as a complication associated with their use. Otherwise, the use of endosseous implants in oral rehabilitation is a well-established procedure, with good long-term success although systemic factors may affect the bone healing around dental implants. We report the first case reported of MM adjacent to a mandibular dental implant in a patient who developed BRONJ in the same area after intravenous zoledronate treatment. We discuss possible pathogeny of this particular and interesting phenomena.

Non-surgical management of stage 3 biphosphonate-related oroantral fistula

We describe the case of a patient with an oroantral fistula that healed successfully after conservative treatment.

Bisphosphonate osteonecrosis of the jaw: a literature review of UK policies versus international policies on the management of bisphosphonate osteonecrosis of the jaw

Despite the increasing number of cases of osteonecrosis of the jaws related to bisphosphonate therapy described in the literature there is a paucity of evidence-based treatment for the condition. In this second article on bisphosphonate-related jaw complications we discuss the different treatment strategies for the condition, review current literature, particularly in relation to the recommendations that have been published, and discuss the evidence behind them.

Clinical experiences with bisphosphonate-associated osteonecrosis of the jaws: analysis of 21 cases

PURPOSE

The aim of the present study was to analyze the clinical presentation, risk factors, radiologic features, histopathologic and microbiological findings, treatment, and evolution of bisphosphonate-associated osteonecrosis of the jaws (BONJ).

METHODS

This study made a retrospective review of 21 patients who underwent treatment and diagnosis of BONJ during 2004 to 2007 in a tertiary health care center reference for 1,100,000 inhabitants.

RESULTS

The mean patient age at the time of presentation was 65.1 years. Of the 21 patients observed, 19 (90.4%) were receiving intravenous zoledronate. Of the 21 patients, 15 were treated with bisphosphonates for bone metastasis (71.4%), 5 for multiple myeloma (23.8%), and 1 for rheumatoid arthritis (4.7%). In 17 patients, the lesions occurred in the mandible. Fifteen patients had previous tooth extractions at the same site of bone necrosis.

CONCLUSION

In our series, most patients improved with conservative surgical debridement. Prospective clinical trials would enable clinicians to make accurate judgments about risk, treatment, and outcome for patients with BONJ.

Bisphosphonate-associated osteonecrosis of the jaw: what do we currently know? A survey of knowledge given in the recent literature

Increasing application of bisphosphonates for therapy of osteopathies has led to reports of the severe associated adverse effects of osteonecrosis of the jaw (ONJ). We reviewed recent literature to assess several aspects of bisphosphonate-associated ONJ, and to provide healthcare professionals with an overview of treatment and preventive options. Literature databases were searched using keywords. Information of 54 articles were discussed and completed by additional literature. High-risk factors were application of nitrogen-containing bisphosphonates, teeth extractions, and ill-fitting dentures. Treatment included non-surgical options and radical surgery. Success and failure were described for all treatment options; further studies investigating long-term recovery and recurrence are warranted. Paying attention to effective prevention of ONJ before, during, and after treatment is essential.

Oral bisphosphonates as a cause of bisphosphonate-related osteonecrosis of the jaws: clinical findings, assessment of risks, and preventive strategies

PURPOSE

Oral bisphosphonates are known to have potentially profound effects on oral health. A review of the evidence supporting answers to key clinical questions is necessary to assist surgeons in the care of their patients who are receiving oral bisphosphonates.

MATERIALS AND METHODS

The literature is reviewed to address several questions, ie, what is the risk of bisphosphonate-related osteonecrosis of the jaws (BRONJ) in my patient on oral bisphosphonates? Why are so few cases of BRONJ attributable to oral bisphosphonate use? What is the importance of cofactors in the development of osteonecrosis? How major a clinical problem is BRONJ, typically, in the oral bisphosphonate patient? What dental procedures are associated with a risk of BRONJ? Are other findings apart from BRONJ of importance in the oral bisphosphonate patient? Are there proven strategies to prevent BRONJ in the oral bisphosphonate patient? Should my patient discontinue the use of oral bisphosphonates temporarily or permanently?

RESULTS

A review of the evidence offers information that will help in clinical decision-making. In general, the risk of BRONJ is between 1 in 10,000 and 1 in 100,000, but may increase to 1 in 300 after dental extraction. The great majority of BRONJ cases will likely remain in the intravenous population. Cofactors have not been firmly established, although smoking, steroid use, anemia, hypoxemia, diabetes, infection, and immune deficiency may be important. Rarely does BRONJ in the oral bisphosphonate patient appear to progress beyond stage 2, and many cases reverse with discontinuation of oral medication. Extraction is the only dental procedure shown to increase the risk of BRONJ. Dental implant therapy should be used with caution in the oral bisphosphonate patient. The benefits and risks of oral bisphosphonate use must be weighed individually and in consultation with the prescribing physician, before determining the need for temporary or permanent cessation of medication.

CONCLUSION

Emerging evidence supports clinical decisions in favor of the oral and maxillofacial surgery patient taking oral bisphosphonates.