Normal serum bone markers in bisphosphonate-induced osteonecrosis of the jaws

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.

Vitamin D Deficiency and Oral Health: A Comprehensive Review

Vitamin D (VD) levels have been gaining growing attention in Oral Health. During growth and adulthood, VD deficiency (VDD) is associated with a wide variety of oral health disorders, and impaired VD synthesis may expedite some of these conditions. In children, severe VDD can induce defective tooth mineralization, resulting in dentin and enamel defects. As a consequence, these defects may increase the risk of the onset and progression of dental caries. Further, VDD has been associated with higher prevalence of periodontitis and gingival inflammation, and several recent preclinical and clinical studies have unveiled potential pathways through which Vitamin D may interact with the periodontium. VDD correction through supplementation may contribute to a successful treatment of periodontitis; however, alveolar bone regeneration procedures performed in baseline VDD patients seem more prone to failure. Vitamin D may also be linked with some oral pathology entities such as certain oral cancers and events of osteonecrosis of the jaw. This review aims to provide comprehensive evidence of how VD levels should be considered to promote good oral health, and to summarize how VDD may hamper oral development and its role in certain oral conditions.

Prevalence and risk factors of medication-related osteonecrosis of the jaw in osteoporotic and breast cancer patients: a cross-sectional study

PURPOSE

Medication-related osteonecrosis of the jaw (MRONJ) has been reported as a side effect of bisphosphonate (BP). The aim of this study was to identify the prevalence of MRONJ in women taking BP for osteoporosis and for metastatic breast cancer and correlate it with risk factors and biochemical markers of bone metabolism.

METHODS

Patients taking oral or intravenous BP with osteoporosis (G1; n = 153; median 72.8 years) and with metastatic breast cancer (G2; n = 134; median 58.2 years) had their hospital charts reviewed, were submitted to dental inspection, and answered a health questionnaire. Fasting blood samples were randomly collected from both groups to measure osteocalcin, carboxy-terminal cross-linking telopeptide of type I collagen, intact parathyroid hormone and procollagen type 1 amino-terminal propeptide (P1NP), 25 hydroxyvitamin D (25OHD), creatinine, and total calcium.

RESULTS

G1 was older (p = 0.001) and had more cases of diabetes (p = 0.043). P1NP was higher (p = 0.022) and 25OHD lower (p = 0.004) in G2 compared with G1. MRONJ was not found in the G1, whereas 4 cases (3%) were detected in G2. Positive risk factors for MRONJ were number of BP doses and number of visits to the dentist and dental extractions. The biochemical parameters, however, could not identify those who developed MRONJ.

CONCLUSIONS

The prevalence of MRONJ was 3% in women with metastatic breast cancer receiving BP. No cases were identified in women receiving oral BP chronically for osteoporosis. P1NP was higher in women with metastatic breast cancer, even during treatment with antiresorptives, but could not differentiate those with MRONJ.

Association between biomarkers and medication-related osteonecrosis of the jaws: a systematic review

OBJECTIVES

Our aim was to conduct a systematic review (SR) of the literature assessing the role of human biomarkers in the diagnosis or prognostication of medication-related osteonecrosis of the jaws (MRONJ).

STUDY DESIGN

An electronic search without date or language restriction was carried out in PubMed/MEDLINE, the Cochrane Central Register of Controlled Trials, Web of Science, and LILACS for publications until March 2018. In addition, a manual search in the gray literature was conducted. The search process was performed by 2 independent reviewing authors. Eligibility criteria included randomized and nonrandomized clinical trials, prospective or retrospective cohorts, case controls, and case series evaluating the association between biomarkers and MRONJ. The protocol of this SR was registered in PROSPERO under number CRD42018095886.

RESULTS

The search and selection process yielded 19 studies (2 case series, 6 case-control studies, 9 prospective cohort studies, and 2 retrospective studies) published between 2008 and 2018. Twenty-four biomarkers collected from serum, saliva, and urine were investigated by these studies. Eleven biomarkers were possibly related to MRONJ; however, no consensus is observed in the literature with regard to the sensitivity and clinical effectiveness of these biomarkers.

CONCLUSIONS

Although many biomarkers have been associated with MRONJ, the present SR found scarce clinical evidence supporting the use of these biomarkers for the diagnosis and prognosis of MRONJ.

Vitamin D (25-OHD) deficiency may increase the prevalence of medication-related osteonecrosis of the jaw

INTRODUCTION

Osteonecrosis of the jaw (ONJ) is a severe complication of antiresorptive medication (AM) in the treatment of bone-affecting cancer-related conditions and osteoporosis. Aim of this study was to reveal whether patients treated with AM and show Medication Related OsteoNecrosis of the Jaw (MRONJ) are vitamin D deficient or not.

MATERIALS AND METHODS

A 2 year retrospective study evaluated hospital records of 63 patients who received AM. Patients were divided into two groups. One group (n = 45) consisted of patients who presented a stage 2 ONJ (eb+ = exposed bone). Second group patients (n = 18) (eb- = no exposed bone) presented for extraction of teeth. Serum levels of vitamin D (25-OHD) were analysed. P values ≤ 0.05 in t-test were regarded as statistically significant.

RESULTS

Serum levels of 25-OHD were significantly higher in the eb(-) group (29.5 ng/ml), than in the eb(+) group (20.49 ng/ml). Blood levels of calcium were also significantly higher in eb(-) group (2.25 mmol/L; 0.11 SD) than in eb(+) group (2.175 mmol/L; 0.16 SD).

CONCLUSION

Prevalence of MRONJ in AM treated patients seems to be increased by low serum 25-OHD. A measurable tendency in the role of 25-OHD for the development of MRONJ was recorded and leads to the recommendation for a sufficient vitamin D substitution in patients treated with AM.

Effects of zoledronic acid and geranylgeraniol on the cellular behaviour and gene expression of primary human alveolar osteoblasts

INTRODUCTION

Bisphosphonate-related osteonecrosis of the jaw (BRONJ) is a serious complication of bisphosphonate therapy. The mechanism underlying BRONJ pathogenesis is poorly understood.

OBJECTIVES

To determine the effects of zoledronic acid (ZA) and geranylgeraniol (GGOH) on the mevalonate pathway (MVP) in osteoblasts generated from the human mandibular alveolar bone in terms of cell viability/proliferation, migration, apoptosis and gene expression.

MATERIALS AND METHODS

Primary human osteoblasts (HOBs) isolated from the mandibular alveolar bone were phenotyped. HOBs were cultured with or without ZA and GGOH for up to 72 h. Cellular behaviour was examined using a CellTiter-Blue® viability assay, an Ibidi culture-insert migration assay, an Apo-ONE® Homogeneous Caspase-3/7 apoptosis assay and transmission electron microscopy (TEM). Quantitative real-time reverse transcriptase polymerase chain reaction (qRT²-PCR) was used to determine the simultaneous expression of 168 osteogenic and angiogenic genes modulated in the presence of ZA and GGOH.

RESULTS

ZA decreased cell viability and migration and induced apoptosis in HOBs. TEM revealed signs of apoptosis in ZA-treated HOBs. However, the co-addition of GGOH ameliorated the effect of ZA and partially restored the cells to the control state. Twenty-eight genes in the osteogenic array and 27 genes in the angiogenic array were significantly regulated in the presence of ZA compared with those in the controls at one or more time points.

CONCLUSION

The cytotoxic effect of ZA on HOBs and its reversal by the addition of GGOH suggests that the effect of ZA on HOBs is mediated via the MVP.

CLINICAL RELEVANCE

The results suggest that GGOH could be used as a possible therapeutic/preventive strategy for BRONJ.

Genetic association between VEGF polymorphisms and BRONJ in the Korean population

OBJECTIVES

The purpose of this study was to evaluate the association between vascular endothelial growth factor (VEGF) polymorphisms and bisphosphonate-related osteonecrosis of the jaw (BRONJ) in the Korean population.

SUBJECTS AND METHODS

Forty-five individuals (2 men, 43 women; mean age: 68.7 ± 12.3 years) were recruited for this study. All visited the Yonsei University Dental Hospital for surgical intervention from January 2012 to January 2013 and had a history of bisphosphonate (BP) administration (oral and/or intravenous). Patients were allocated to case (n = 26) or control (n = 19) groups according to the patients' selection criteria. Association between three VEGF single nucleotide polymorphisms (rs699947 (-2578 C>A), rs2010963 (-634 G>C) and rs3025039 (+936 C>T)) and BRONJ were investigated using multiple logistic regression analysis and Fisher's exact test where appropriate (α = 0.05).

RESULTS

The CC homozygotes of rs2010963 and rs3025039 of VEGF gene were associated with an increased risk of BRONJ (P = 0.04, 0.03, respectively). In haplotype analysis, no differences in haplotype C-C (-2578/-634) and haplotype C-C-C (-2578/-634/+936) were observed.

CONCLUSION

The CC homozygotes of rs2010963 and rs3025039 polymorphisms in the VEGF gene were associated with an increased risk of BRONJ in the Korean population. Further epidemiological cohort studies with a larger sample size would be required to confirm the suggestive correlations.

Salivary Biomarkers Associated With Bone Deterioration in Patients With Medication-Related Osteonecrosis of the Jaws

PURPOSE

The purpose of this study was to investigate the use of saliva as a medium for the identification of biomarkers associated with bone resorption and formation. The authors hypothesized that biomarkers, such as N-telopeptide of type I collagen (NTX) and bone-specific alkaline phosphatase (B-AP), could be identified in saliva. They further hypothesized that there would be a difference between these biomarkers in the saliva of patients with medication-relation osteonecrosis of the jaws (MRONJ) and those who have no risk factors for the development of MRONJ.

PATIENTS AND METHODS

This case-and-control study compared 2 salivary biomarkers, NTX and B-AP, in a group of patients with MRONJ and a control group. The predictor variable was the presence or absence of the disease (MRONJ or control group); the outcome variables were the levels of the 2 salivary biomarkers, NTX and B-AP. Saliva samples from 20 patients with a diagnosis of MRONJ and 14 control participants who were comparable to the study group with no history of antiresorptive medication use were collected. The saliva samples were analyzed using 2 commercially available assays for NTX and B-AP to evaluate for levels of each marker. A 2-tailed t test for 2 groups of unequal distribution was used for statistical analysis, with P values less than .05 considered statistically.

RESULTS

The 2 biomarkers, NTX and B-AP, were detected in saliva samples from the MRONJ and control groups. A statistically significant difference was found in the levels of NTX in saliva of patients with MRONJ compared with the control participants (P = .0067).

CONCLUSIONS

In this exploratory study, the 2 bone deterioration biomarkers (NTX and B-AP) were detected in saliva. There was a statistical difference in the levels of salivary NTX between patients with MRONJ and controls. Saliva evaluation could provide a novel method to detect, diagnose, stage, and potentially guide treatment decisions and monitor outcomes for patients with MRONJ in the future.

Diagnosis and management of osteonecrosis of the jaw: a systematic review and international consensus

This work provides a systematic review of the literature from January 2003 to April 2014 pertaining to the incidence, pathophysiology, diagnosis, and treatment of osteonecrosis of the jaw (ONJ), and offers recommendations for its management based on multidisciplinary international consensus. ONJ is associated with oncology-dose parenteral antiresorptive therapy of bisphosphonates (BP) and denosumab (Dmab). The incidence of ONJ is greatest in the oncology patient population (1% to 15%), where high doses of these medications are used at frequent intervals. In the osteoporosis patient population, the incidence of ONJ is estimated at 0.001% to 0.01%, marginally higher than the incidence in the general population (<0.001%). New insights into the pathophysiology of ONJ include antiresorptive effects of BPs and Dmab, effects of BPs on gamma delta T-cells and on monocyte and macrophage function, as well as the role of local bacterial infection, inflammation, and necrosis. Advances in imaging include the use of cone beam computerized tomography assessing cortical and cancellous architecture with lower radiation exposure, magnetic resonance imaging, bone scanning, and positron emission tomography, although plain films often suffice. Other risk factors for ONJ include glucocorticoid use, maxillary or mandibular bone surgery, poor oral hygiene, chronic inflammation, diabetes mellitus, ill-fitting dentures, as well as other drugs, including antiangiogenic agents. Prevention strategies for ONJ include elimination or stabilization of oral disease prior to initiation of antiresorptive agents, as well as maintenance of good oral hygiene. In those patients at high risk for the development of ONJ, including cancer patients receiving high-dose BP or Dmab therapy, consideration should be given to withholding antiresorptive therapy following extensive oral surgery until the surgical site heals with mature mucosal coverage. Management of ONJ is based on the stage of the disease, size of the lesions, and the presence of contributing drug therapy and comorbidity. Conservative therapy includes topical antibiotic oral rinses and systemic antibiotic therapy. Localized surgical debridement is indicated in advanced nonresponsive disease and has been successful. Early data have suggested enhanced osseous wound healing with teriparatide in those without contraindications for its use. Experimental therapy includes bone marrow stem cell intralesional transplantation, low-level laser therapy, local platelet-derived growth factor application, hyperbaric oxygen, and tissue grafting.

Effects of alendronate on the peri-implant bone in rats

OBJECTIVES

The purpose of this study was to determine the effects of alendronate on the peri-implant bone in rat maxillae with the aid of micro-computed tomographic, histologic, and biochemical analyses.

MATERIALS AND METHODS

Thirty-six male Sprague-Dawley rats were used. After extraction of the maxillary first molars, each rat was given periodic subcutaneous injections of either alendronate (alendronate group) or saline (control group). Customized implants were placed bilaterally 4 weeks after these injections. The rats were sacrificed at either 4, 8, or 12 weeks after implantation (4-, 8-, and 12-week groups, respectively; n = 6 rats per group). Microcomputed tomographic and histologic analyses were conducted for all rats. Biochemical analyses were performed at four time points for the 12-week groups.

RESULTS

There were no significant differences between the groups on microcomputed tomographic and histologic analyses. All of the measured biochemical parameters tended to decrease over time, with significant differences among some time points within each group. The serum osteocalcin level was significantly lower in the 12-week alendronate group than in the control group (P < 0.05).

CONCLUSIONS

Three approaches were utilized in evaluating the effects of alendronate. It appears serum osteocalcin levels may serve as an adjuvant marker for this purpose, although further studies are required to confirm this.

Conservative surgical management of stage I bisphosphonate-related osteonecrosis of the jaw

Purpose. To report the efficacy of conservative surgical treatment for stage I bisphosphonate-related osteonecrosis of the jaw (BRONJ). Materials and Methods. This study reports the clinical outcomes of 63 patients treated for BRONJ stage I (according to Ruggiero's staging system) at the Oral Pathology and Laser-Assisted Surgery Unit of the University of Parma between January 2004 and January 2011. Surgical interventions were performed, under local analgesia, in patients unresponsive for a period of six months to noninvasive treatments such as cycles of local or systemic antibacterial therapy combined or not to low level laser therapy, ozone therapy, or Hyperbaric Oxygen Therapy. All interventions were performed after the consultation of oncologist or physician. Results. In our experience, conservative surgical treatment is associated with the highest number of BRONJ healed sites in stage I disease. Complete healing was observed in 92.6% of sites surgically treated. Conclusions. This study confirms that treatment of patients affected by minimal bone exposition, (stage I of BRONJ), through conservative surgical strategies, possibly with laser, may result in a high control of the disease in the long term.

Important aspects concerning alendronate-related osteonecrosis of the jaws: a literature review

OBJECTIVE

To conduct a literature review on sodium alendronate, focusing on osteonecrosis of the jaws, a serious potential side effect.

BACKGROUND

Sodium alendronate is a bisphosphonate that is widely used for the treatment of osteopenia, osteoporosis and Paget's disease. Like other bisphosphonates, it inhibits bone resorption by inactivating osteoclasts. Alendronate has evident benefits in the treatment of these diseases, but it is associated with jaw osteonecrosis, although less frequently compared with intravenous bisphosphonates. Therefore, some preventive measures should be taken to avoid this side effect.

MATERIAL AND METHODS

We reviewed the literature regarding the pharmacological aspects, mechanism of action, indications of use and side effects of sodium alendronate, as well as the management of patients under this therapy.

CONCLUSION

The benefits of sodium alendronate are scientifically proven, but a serious adverse effect is osteonecrosis. Therefore, it is crucial to prepare the oral cavity before bisphosphonate therapy, providing a careful dental evaluation and all needed dental treatment.

Prospective biomarker evaluation in patients with osteonecrosis of the jaw who received bisphosphonates

Bone biomarkers have been suggested for the risk assessment for osteonecrosis of the jaw, a serious complication associated with bisphosphonate (BP) use; however, no consensus has been reached. This study investigated the possible associations between bone biomarkers and the development of bisphosphonates-related osteonecrosis of the jaw (BRONJ). This is a case-control study of 37 patients with BRONJ (age, 73.6±11.2years) who had at least 1 sample available at diagnosis, out of which, 35 were taking BPs for osteoporosis and 2 patients for bone metastasis. Age- and gender-matched 37 patients who had been exposed to BPs for >24months and had no evidence of BRONJ after dentoalveolar surgery served as control group. The association between biomarkers (osteocalcin [OC], deoxypyridinoline [DPD], C-terminal telopeptide of collagen I [CTX], N-terminal telopeptides [NTX], bone-specific alkaline phosphatase [BAP], and parathyroid hormone [PTH]) and BRONJ development, the effects of BP discontinuation on biomarkers, and the performance of biomarkers for risk assessment were investigated. In our study, the PTH levels were found to be significantly higher in BRONJ patients compared to controls (P<0.05). But the OC, DPD, CTX, NTX, and BAP levels were not significantly different between the 2 groups (P>0.05). The CTX level in reference to a 150pg/mL cutoff was also not significant for BRONJ development (P>0.05). Among BRONJ patients who discontinued BP, in a linear mixed model, only CTX showed a significant increase over time (β=0.002, P=0.007). The cutoff PTH level was >41.52pg/mL (AUC=0.719, P=0.009), and that of CTX was ≤0.094ng/mL (AUC=0.619, P=0.069). In conclusion, there is insufficient evidence for the risk prediction for BRONJ of current bone biomarkers; additional research is necessary.

Zoledronic acid in genitourinary cancer

Bone metastases are a common complication of advanced prostate cancer and while they are less common in non-prostate genitourinary (GU) malignances, they have been reported in up to 35 % of patients with advanced renal cell carcinoma and bladder cancer. Furthermore, they may occur in more than two-thirds of those patients with bladder cancer who develop distant metastases. In the absence of bone-targeted therapies, approximately 50 % of all patients with metastatic bone disease from GU cancers experience at least one skeletal-related event within their lifetime. Zoledronic acid is a bisphosphonate that has been shown to delay or prevent the development of skeletal complications in patients with bone metastases and reduce bone pain in these patients. Furthermore, zoledronic acid has also demonstrated the ability to prevent osteopenia, which may occur with the prolonged use of some pharmacological interventions in patients with cancer.

Factors predicting the prognosis of oral alendronate-related osteonecrosis of the jaws: a 4-year cohort study

BACKGROUND

Studies concerning prognostic factors specific for alendronate-related osteonecrosis of the jaws (ONJ) are rare.

METHODS

We surveyed a cohort of 100 osteoporotic patients with 111 alendronate-related ONJ lesions treated during a 4-year period. Prognostic values of clinical variables and serum markers of bone turnover were assessed by univariate and multivariate analyses.

RESULTS

The cumulative complete response rate at 6 months was 48.65%. Serum bone-specific alkaline phosphatase (BSAP) level >10 μg/L, lesion depth ≦ 10 mm, and lesions in anterior regions denoted a better chance of healing within 6 months and the adjusted hazard ratios were 2.48 (95% confidence interval [CI], 1.41-4.37), 2.71 (95% CI, 1.57-4.70), and 3.94 (95% CI, 1.87-8.30), respectively.

CONCLUSIONS

Early discovery of lesions and prevention of their deeper extension are crucial for improving the prognosis of alendronate-related ONJ. A higher pretreatment level of BSAP indicates a better prognosis.

Emerging concepts in the management and treatment of osteonecrosis of the jaw

Since the first description of bone necrosis in patients receiving bisphosphonate therapy in 2004, there have been multiple retrospective, prospective, and case-control studies that have served to characterize the diagnosis, associated risk factors, and treatment of this new complication. Bisphosphonate-related osteonecrosis of the jaw is at present associated with several risk factors that are identified across several disciplines in medicine and dentistry. With this level of broad-based recognition, new clinical and basic science research initiatives have begun and are likely to elucidate the etiopathogenesis of this disease process, significantly improving the level of disease management and prevention.

Bisphosphonate related osteonecrosis of the jaws: report of two cases

Bisphosphonates are compounds used to treat osteoporosis and malignant bone metastasis. Despite the benefits related to the use of these medications, osteonecrosis of the jaws is a significant complication in a subset of patients receiving these drugs. This complication occurs either spontaneously or after a simple dento-alveolar surgery. Recently there were two patients who showed the features of bisphosphonate related osteonecrosis of the jaws (BRONJ) in Gangneung-Wonju National University Dental Hospital. The patients revealed the clinical and radiological features of classical osteomyelitis. This report presents two cases of BRONJ which were examined by plain radiography and computed tomography.

Safety of bisphosphonates

Bisphosphonates are one of the most well studied groups of medications and they are bone specific. This tissue specificity is a rare property for a drug introduced into clinical practice as long as 40 years ago. Over the years, the therapeutic boundaries of bisphosphonates were explored and their safety profile has withstood the challenges of the harsh clinical reality and widespread use. Certainly, the esophageal or gastric irritation caused by the oral preparations is an established adverse effect, the risk of which can be reduced by the recommended routine of taking the medication. From the other reported associations with adverse events, osteonecrosis of the jaw (ONJ) and subtrochanteric fractures have attracted most of the attention mainly because their pathophysiology remains unclear. However, overall, only a very small proportion of patients treated with bisphosphonates, especially with the oral formulations, experience adverse events and the overall benefits have consistently outweighed their potential risks. Furthermore, bisphosphonates improve the quality of life in patients with metastatic bone cancer and delay the development of adverse skeletal effects.

Zoledronic acid: clinical utility and patient considerations in osteoporosis and low bone mass

The availability of a once-a-year zoledronic acid infusion heralds a new era in the management of osteoporosis. It virtually eliminates the problem of poor compliance with orally administered bisphosphonates and, because it bypasses the gastrointestinal tract, it is not associated with gastrointestinal side effects. Zoledronic acid is effective for the treatment and prevention of postmenopausal osteoporosis, and for the treatment of osteoporosis in men, and glucocorticoid-induced osteoporosis. When administered within three months of a hip fracture, it reduces mortality and the risk of subsequent fractures. It is remarkably free of serious adverse effects. After administration of the intravenous infusion, about 18% of bisphosphonate-naïve patients experience an acute-phase reaction, including low-grade temperature, aches, and pains. This is reduced to about 9% in those who have been treated with oral bisphosphonates, and is further reduced by the concomitant and subsequent administration of acetaminophen. The likelihood and magnitude of the acute-phase reaction is less after the second infusion. Other adverse effects are similar to those encountered with other bisphosphonates. Because it is mostly excreted by the kidneys, zoledronic acid should not be administered to patients with a creatinine clearance less than 35 mL/min. It should not be administered to patients with hypocalcemia.

Bisphosphonate-related osteonecrosis of the jaw: an overview

Bisphosphonates are widely used in the management of metastatic disease to bone and in diseases of altered bone turnover. Recently, multiple-case series and retrospective studies have established a relationship between necrotic bone lesions localized to the jaw and the use of chronic bisphosphonate therapy. This condition has been named bisphosphonate-related osteonecrosis of the jaw (BRONJ). To evaluate the potential risks associated with this new and emerging complication, stage-specific management strategies and guidelines have been developed. In view of the widespread use of chronic bisphosphonate therapy, the observation of an associated risk of osteonecrosis of the jaw should alert practitioners to monitor for this previously unrecognized complication and to reevaluate the indications for and the duration of bisphosphonate therapy in patients with osteopenia/osteoporosis and cancer. Morbidity associated with BRONJ might be prevented or reduced by implementing prevention strategies and establishing early diagnostic procedures. The current widespread use of bisphosphonates as an inhibitor of bone resorption is directly attributable to their efficacy in improving the quality of life for patients with metastatic bone cancer, osteoporosis, and Paget's disease.

Serologic bone markers for predicting development of osteonecrosis of the jaw in patients receiving bisphosphonates

PURPOSE

Osteonecrosis of the jaw is a well-documented side effect of bisphosphonate (BP) use. Attempts have recently been made to predict the development of bisphosphonate-related osteonecrosis of the jaw (BRONJ). We prospectively investigated the predictive value of serum levels of C-terminal telopeptide of collagen I (CTX), bone-specific alkaline phosphatase, and parathyroid hormone for the development of BRONJ.

PATIENTS AND METHODS

Data on the demographics, comorbidities, and BP treatment were collected from 78 patients scheduled for dentoalveolar surgery. Of the 78 patients, 51 had been treated with oral BPs and 27 had been treated with frequent intravenous infusions of BPs. Blood samples for CTX, bone-specific alkaline phosphatase, and parathyroid hormone measurements were taken preoperatively. Surgery was performed conservatively, and antibiotic medications were prescribed for 7 days.

RESULTS

Of the 78 patients, 4 patients taking oral BPs (7.8%) and 14 receiving intravenous BPs (51.8%) developed BRONJ. A CTX level less than 150 pg/mL was significantly associated with BRONJ development, with an increased odds ratio of 5.268 (P = .004). The bone-specific alkaline phosphatase levels were significantly lower in patients taking oral BPs who developed BRONJ. The parathyroid hormone levels were similar in patients who did and did not develop BRONJ.

CONCLUSION

The incidence of BRONJ after oral surgery involving bone is greater among patients receiving frequent, intravenous infusions of BPs than among patients taking oral BPs. Although the measurement of serum levels of CTX is not a definitive predictor of the development of BRONJ, it might have an important role in the risk assessment before oral surgery.

Long-term treatment with bisphosphonates and their safety in postmenopausal osteoporosis

Bisphosphonates are the leading drugs for the treatment of osteoporosis. In randomized controlled trials (RCTs), alendronate, risedronate, and zoledronate have shown to reduce the risk of vertebral, nonvertebral, and hip fractures, whereas RCTs with ibandronate show antifracture efficacy at vertebral sites. Bisphosphonates are generally well tolerated and safe. Nevertheless, adverse events have been noted, and it is important to consider the strength of the evidence for causal relationships. Effects on the gastrointestinal tract and kidney function are well recognized, as are transient acute-phase reactions. Atrial fibrillation was first identified as a potential adverse event in a zoledronate trial, but subsequent trials and analyses failed to substantiate an association with bisphosphonates. Case reports have suggested a relationship between oral bisphosphonates and esophageal cancer, but this has not been demonstrated in epidemiologic studies. A possible association between bisphosphonate use and osteonecrosis of the jaw (ONJ) has also been suggested. However, the risk of ONJ in patients with osteoporosis appears to be very low, with no evidence from prospective RCTs of a causal association. There are reports of occasional occurrence of subtrochanteric or diaphyseal fractures in osteoporotic patients, but an association with bisphosphonate therapy is not substantiated by epidemiologic studies or prospective RCTs.

Bisphosphonate-related osteonecrosis of the jaw: position paper from the Allied Task Force Committee of Japanese Society for Bone and Mineral Research, Japan Osteoporosis Society, Japanese Society of Periodontology, Japanese Society for Oral and Maxillofacial Radiology, and Japanese Society of Oral and Maxillofacial Surgeons

Bisphosphonates (BPs) have been widely, efficiently, and safely used for the treatment of osteoporosis, malignant hypercalcemia, bone metastasis of solid cancers, and multiple myeloma bone diseases. Accumulating recent reports describe that surgical dental treatments in patients with cancer or osteoporosis who have been receiving intravenous or oral BPs are associated with osteonecrosis of the jaw (bisphosphonate-related osteonecrosis of the jaw, BRONJ). The accurate incidence, clinical backgrounds, and pathogenesis of BRONJ have been unclear and appropriate approaches for prevention and treatment have not been established to date. To address the current situation of BRONJ in Japan, the "Allied Task Force Committee of Bisphosphonate-Related Osteonecrosis of the Jaw," consisting of physicians specializing in bone biology, orthopedic surgery, rheumatology, obstetrics/gynecology, and medical oncology and dentists specializing in oral surgery, periodontology, dental radiology, and oral pathology, was organized. The committee attempted to propose a standard position paper for the treatment of BRONJ. The committee expects that this proposal will provide objective and correct scientific information on BRONJ and will serve as a reference for conducting dental procedures for patients receiving BPs and in designing prevention and treatment of BRONJ. However, because this position paper is not based on direct clinical evidence, it should be used as a reference, and a decision on treatment in each case should be made after an extensive discussion among physicians, dentists/oral surgeons, and the patients.

Increased prevalence of bisphosphonate-related osteonecrosis of the jaw with vitamin D deficiency in rats

Necrotic bone exposure in the oral cavity has recently been reported in patients treated with nitrogen-containing bisphosphonates as part of their therapeutic regimen for multiple myeloma or metastatic cancers to bone. It has been postulated that systemic conditions associated with cancer patients combined with tooth extraction may increase the risk of osteonecrosis of the jaw (ONJ). The objective of this study was to establish an animal model of bisphosphonate-related ONJ by testing the combination of these risk factors. The generation of ONJ lesions in rats resembling human disease was achieved under the confluence of intravenous injection of zoledronate (ZOL; 35 microg/kg every 2 weeks), maxillary molar extraction, and vitamin D deficiency [VitD(-)]. The prevalence of ONJ in the VitD(-)/ZOL group was 66.7%, which was significantly higher (p < .05, Fisher exact test) than the control (0%), VitD(-) (0%), and ZOL alone (14.3%) groups. Similar to human patients, rat ONJ lesions prolonged the oral exposure of necrotic bone sequestra and were uniquely associated with pseudoepitheliomatous hyperplasia. The number of terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-biotin nick-end label-positive (TUNEL(+)) osteoclasts significantly increased on the surface of post-tooth extraction alveolar bone of the VitD(-)/ZOL group, where sustained inflammation was depicted by [(18)F]fluorodeoxyglucose micro-positron emission tomography (microPET). ONJ lesions were found to be associated with dense accumulation of mixed inflammatory/immune cells. These cells, composed of neutrophils and lymphocytes, appeared to juxtapose apoptotic osteoclasts. It is suggested that the pathophysiologic mechanism(s) underpinning ONJ may involve the interaction between bisphosphonates and compromised vitamin D functions in the realm of skeletal homeostasis and innate immunity.

Bisphosphonate-associated osteomyelitis of the jaw: guidelines for practicing clinicians

OBJECTIVE

To evaluate the literature and discuss the risk factors, mechanisms, pathophysiologic aspects, and recommended management of bisphosphonate-associated osteomyelitis of the jaw (BAOMJ).

METHODS

More than 350 published articles, case reports mentioning BAOMJ, and independent histology slides from BAOMJ lesions were reviewed critically. The most pertinent publications are cited and discussed.

RESULTS

The incidence of BAOMJ increases after extraction of teeth, dentoalveolar surgical procedures, or recent oral trauma leading to exposed maxillary or mandibular bone. Contributory factors include poor oral hygiene, oral infections, periodontal disease; recent or ongoing corticosteroid administration or chemotherapy; compromised immune status; diabetes or vascular insufficiency; old age; chronic diseases; and malignancies. On average, 1 of every 100,000 patients treated with bisphosphonates orally for osteoporosis or Paget disease of bone may develop BAOMJ-like lesions. Patients with cancer often receive bisphosphonate doses 10 times or higher, and also more frequently, than those used in patients with osteoporosis or Paget disease of bone. Therefore, greater frequency of administration of bisphosphonates, higher dosages, and prolonged use (that is, for more than 2 years) are likely to be factors triggering BAOMJ.

CONCLUSION

The association of bisphosphonate therapy with BAOMJ is rare in noncancer patients and is likely to be a class effect that may occur with use of any bisphosphonate. Whether patients with cancer require such a high frequency of intravenously administered bisphosphonates needs to be investigated. Following established guidelines can decrease the risks of BAOMJ in vulnerable patients. Rather than necrotic bone, current evidence supports an infectious and perhaps immunologic underlying cause for BAOMJ. The estimated incidence of BAOMJ among noncancer patients receiving bisphosphonates is about 0.001%, whereas among patients with cancer receiving intravenous bisphosphonate therapy the incidence is between 0.5% and 4%, depending on the dose, frequency, and duration of therapy (on average, approximately 2%). Nevertheless, the benefits of bisphosphonates far outweigh the risks.

Osteonecrosis of the jaws in patients treated with intravenous bisphosphonates (BRONJ): A concise update

Bisphosphonate-related osteonecrosis of the jaws (BRONJ) is a severe complication seen most frequently in patients on intravenous bisphosphonates treatment for malignant diseases. High potency bisphosphonates are generally implicated and risk factors also include dental extractions. Prevention is of paramount importance. Management is controversial but there is little evidence basis and the consensus is to be conservative. Recent advances in this area are summarised in this concise review.