Retrospective study of two biochemical markers for the risk assessment of oral bisphosphonate-related osteonecrosis of the jaws: can they be utilized as risk markers?

Organic Bone Matrix Component Type I and V Collagen Are Not Destructed in Bisphosphonate-Associated Osteonecrosis of the Jaws

Background and objectives: The investigation of the pathophysiology behind medication-related osteonecrosis (MRONJ) of the jaw mostly focuses on alterations in osteoclast and osteoblast cell activity, but changes in the organic and inorganic bone matrix have rarely been studied. The aim of this study was to investigate whether collagen, the main organic component of extracellular bone matrix, is destructed in osteonecrosis of the jaw secondary to antiresorptive medication. Material and methods: Bone samples of patients with MRONJ (n = 15, control group n = 3) were demineralized, and collagen fragments were separated from intact collagen pellets by ultrafiltration. The quantification of mature collagen cross-links hydroxylysylpyridinoline (HP) and lysylpyridinoline (LP) in pellets and ultrafiltrates was performed by high-performance liquid chromatography (HPLC). The detection of hydroxyproline (Hyp) was carried out using a spectrophotometric assay. In addition, collagen chains were analyzed by sodium dodecylsulfate-polyacrylamide gel (SDS-PAGE). Results: The results revealed significantly higher concentrations of HP, LP and Hyp in pellet samples. In addition, there were no significant differences between samples from MRONJ patients and those of the control group. These results were paralleled by SDS- PAGE. Conclusion: These findings suggest that MRONJ does not involve the destruction of type I and V collagen molecules, in contrast to previously reported destruction by osteoradionecrosis.

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.

Dental care for patients taking antiresorptive drugs: a literature review

Antiresorptive drugs (ARDs), such as bisphosphonates or denosumab, that prevent bone resorption are widely used in patients with osteoporosis or with cancer that has metastasized to the bones. Although osteonecrosis of the jaw (ONJ) is a well-documented complication of ARD use, the benefits ARDs outweigh the complication. Thus, research has focused on finding ways to prevent or reduce the risk of developing ONJ. Dentists, as part of a multi-professional team, have a critical role in preventing ONJ. However, many dentists tend to hesitate to provide dental care to patients with ONJ, or tend to think that it is a problem to be dealt with by oral surgeons. This review gives an overview of ARD-related ONJ and provides the guidelines for dental care in patients taking ARDs to lower the risk of developing ONJ.

Medication-related osteonecrosis of the jaws after tooth extraction in senescent female mice treated with zoledronic acid: Microtomographic, histological and immunohistochemical characterization

Treatment with cumulative dosages of zoledronic acid (ZA) in elderly patients is a risk factor for the development of medication-related osteonecrosis of the jaws (MRONJ), mainly related to surgical triggers such as tooth extraction. However, animal models for the investigation and understanding of MRONJ pathophysiology in senescent and postmenopausal stages remains to be developed and characterized. The aim of this study was to analyze MRONJ development in senescent female mice treated with cumulative dosages of ZA. For this purpose, twenty 129/Sv female mice, 64 weeks old, were treated with 0.9% saline solution as control group (n = 10), and with ZA at 250μg/Kg (n = 10), once a week, starting 4 weeks before the upper right incisor extraction and until the end of the experimental time points (7 days and 21 days). At 7 and 21 days post-surgery, specimens were harvested for microCT, histological, birefringence and immunohistochemical analysis. Clinically, an incomplete epithelialization was observed in ZA group at 7 days and a delayed bone matrix mineralization and collagen maturation at 7 and 21 days compared to the controls. Controls revealed sockets filled with mature bone at 21 days as observed by microCT and birefringence, while ZA group presented delayed bone deposition at 7 and 21 days, as well increased leukocyte infiltration and blood clot at 7 days, and increased bone sequestrum and empty osteocyte lacunae at 21 days (p<0.05). Also, ZA group presented decreased quantity of TGFb+ and Runx-2+ cells at 7 days, and decreased quantity of TRAP+ osteoclasts compared to the control at 21 days (p<0.05). Altogether, these data demonstrate the usefulness of this model to understanding the pathophysiology of 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.

Cross-Sectional Study of four Serological Bone Turnover Markers for the Risk Assessment of Medication-Related Osteonecrosis of the Jaw

BACKGROUND

Despite the benefits related to the use of bisphosphonates and denosumab, medication-related osteonecrosis of the jaw (MRONJ) is a serious complication. The purpose of this study was to investigate the utility of 4 biochemical markers including serum c-terminal telopeptide cross-link of type I collagen (s-CTX), serum osteocalcin (s-OC), serum parathormon (s-PTH), and serum bone-specific alkaline phosphatase (s-BAP) as useful clinical tools to help assess the risk for MRONJ prior to invasive oral surgery.

MATERIALS AND METHODS

Twenty patients diagnosed with MRONJ and 20 controls who have been on antiresorptive therapies with no occurrence of MRONJ were included in this 2-arm cross-sectional study. The s-CTX, s-OC, s-PTH, and s-BAP values were measured. Mann-Whitney U test compared the s-CTX, s-OC, s-PTH, and s-BAP values of the MRONJ group and the controls (P < 0.05).

RESULTS

Lower values were observed in the MRONJ group compared with the control group for s-CTX (130.00 pg/mL versus 230.0 pg/mL; P = 0.12) and for s-OC (10.6 ng/mL versus 14.80 ng/mL; P = 0.051) both without significance and for s-BAP (0.23 μkat/L versus 0.31 μkat/L; P = 0.002) with significance. By contrast, the median s-PTH value of the MRONJ group was higher (30.65 ng/L versus 25.50 ng/L; P = 0.89), but without significance.

CONCLUSIONS

The evaluation of the 4 biochemical markers showed that only the value of s-BAP was significantly decreased in the MRONJ patients compared with the controls. Presently, because of the lack of evidence, a routine check prior to oral surgery for the risk assessment of MRONJ cannot be recommended.

Short-Term Teriparatide and Recombinant Human Bone Morphogenetic Protein-2 for Regenerative Approach to Medication-Related Osteonecrosis of the Jaw: A Preliminary Study

Our objective was to examine whether adjunct teriparatide administration and local application of recombinant human bone morphogenetic protein-2 (rhBMP-2) is beneficial for the regeneration of jaw bone in patients with medication-related osteonecrosis of the jaw (MRONJ). This study enrolled 17 patients diagnosed with MRONJ. All patients received sequestrectomy under general or local anesthesia with suspension of bisphosphonate. The bone regeneration ratio was compared on cone beam computed tomography (CBCT) scans, acquired immediately post-operation and after 6 months. The patients were divided into groups, based on their treatment regimens: teriparatide combined with rhBMP-2 (parathyroid hormone [PTH]+BMP), rhBMP-2 (BMP), and the control. Biochemical markers were also evaluated at the baseline (T0), 1 month (T1), and 3 months (T2) after surgery. Significant increase was observed in the values of the biochemical markers, serum osteocalcin, and serum C-terminal telopeptide cross-link of type I collagen, within 3 months of surgery in the PTH+BMP group, whereas the mean value in the BMP group did not show a significant change. In all groups, the MRONJ lesions were healed and new bone formation was detected in the CBCT images. The regeneration ratio was significantly greater in the group PTH+BMP than in the BMP and control groups. Significantly greater amount of bone formation was observed in the group PTH+BMP than in the BMP and control groups. Local application of rhBMP-2 alone also had a beneficial effect on bone regeneration but was not more significant than control. Based on these findings, administration of short-term teriparatide with rhBMP-2 in MRONJ patients may maximize the regeneration of bone after surgery. © 2017 American Society for Bone and Mineral Research.

Osteonecrosis

Younger patients are affected more often by osteonecrosis than by osteoarthritis, and osteonecrosis has significantly greater long-term morbidity.

Corticosteroids are the most common cause of nontraumatic osteonecrosis.

The femoral head is the most common site of osteonecrosis.

In rare instances, osteonecrosis of the jaw has been associated with bisphosphonate exposure. This phenomenon is more common with repeated intravenous infusions of bisphosphonates.

Case reports of osteonecrosis of the jaw in association with other medications, such as denosumab, have been reported.

The final common pathway in the pathogenesis of osteonecrosis is disruption of blood supply to a segment of bone.

Abnormalities in lipid metabolism, bone homeostasis, regulation of apoptosis, coagulopathies, innate immunity, and oxidative stress may play a role in the pathogenesis of osteonecrosis.

Epigenetics may alter the predisposition to develop osteonecrosis.

MRI is currently the optimal test for early diagnosis and identification of the extent of osteonecrosis.

Nonsurgical treatment of osteonecrosis does not change the natural history of the disease.

Although surgical treatment of femoral head osteonecrosis has many variations, most symptomatic patients eventually require total hip arthroplasty.

Knowledge of risk factors and early detection are crucial to the successful management of osteonecrosis.

Because of the lack of successful treatment options, new modes of management focus on the prevention of osteonecrosis.

Case-Based Review of Osteonecrosis of the Jaw (ONJ) and Application of the International Recommendations for Management From the International Task Force on ONJ

Osteonecrosis of the jaw (ONJ) has been associated with antiresorptive therapy in both oncology and osteoporosis patients. This debilitating condition is very rare and advances in diagnosis and management may now effectively reduce the risk of its development and offer valuable treatment options for affected patients. This paper provides a case-based review of ONJ and application of the International Task Force on ONJ (referred to as the "Task Force") recommendations for the diagnosis and management of ONJ. The Task Force was supported by 14 international societies and achieved consensus from representatives of these multidisciplinary societies on key issues pertaining to the diagnosis and management of ONJ. The frequency of ONJ in oncology patients receiving oncology doses of bisphosphonate (BP) or denosumab is estimated at 1%-15%, and the frequency in the osteoporosis patient population receiving much lower doses of BP or denosumab is estimated at 0.001%-0.01%. Although the diagnosis of ONJ is primarily clinical, imaging may be helpful in confirming the diagnosis and staging. In those with multiple risk factors for ONJ for whom major invasive oral surgery is being planned, interruption of BP or denosumab therapy (in cancer patients) is advised, if possible, before surgery, until the surgical site heals. Major oral surgery in this context could include multiple extractions if surgical extractions are required, not simple forceps extractions. ONJ development may be reduced by optimizing oral hygiene and postoperatively using topical and systemic antibiotics as appropriate. Periodontal disease should be managed before starting oncology doses of BP or denosumab. Local debridement may be successful in disease unresponsive to conservative therapy. Successful surgical intervention has been reported in those with stage 3 disease; less severe disease is best managed conservatively. Teriparatide may be helpful in healing ONJ lesions and may be considered in osteoporosis patients at a high fracture risk in the absence of contraindications. Resumption of BP or denosumab therapy following healing of ONJ lesions is recommended, and there have not been reports of subsequent local recurrence.

Efficacy of the C-terminal telopeptide test in predicting the development of bisphosphonate-related osteonecrosis of the jaw: a systematic review

This systematic review evaluated the efficacy of the morning fasting serum C-terminal telopeptide (CTX) test in predicting the development of bisphosphonate-related osteonecrosis of the jaw (BRONJ). A comprehensive search of studies published up to March 2016, and listed in the PubMed/MEDLINE, Web of Science, and Cochrane Library databases, was performed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. This review has been registered in the PROSPERO international prospective register of systematic reviews (CRD42016036717). The search identified 542 publications; eight studies were finally deemed eligible for inclusion according to the study criteria. These studies included a total 1442 patients (mean age 66.7 years). The most prescribed drug was alendronate, with osteoporosis being the most frequent indication for the prescription of bisphosphonates. Tooth extraction was the most common trigger for BRONJ. Of all patients evaluated after bisphosphonate treatment, only 24 (1.7%) developed BRONJ. All eight of the selected studies found that CTX levels were not predictive of the development of BRONJ. In conclusion, this systematic review indicates that the CTX test has no predictive value in determining the risk of osteonecrosis in patients taking bisphosphonates.

Role of Teriparatide in Medication-Related Osteonecrosis of the Jaws (MRONJ)

While the optimal treatment concept of medication-related osteonecrosis of the jaws (MRONJ) is still in debate, several adjunct therapies have been introduced. Among these adjunctive measures, recombinant human parathyroid hormone (rhPTH, teriparatide) seems to be the most promising treatment modality. Several studies have presented the beneficial effect of short-term teriparatide; they have shown an improved level of bone markers and radiographic evidence of bone healing. Although clinical validation by a controlled trial with prospective design would be essential, short-term teripratide therapy would be a good treatment option for MRONJ patients with impaired bone remodeling.

Dental implants in patients treated with antiresorptive medication - a systematic literature review

Objective

Bisphosphonate-associated osteonecrosis of the jaws (BP-ONJ) is triggered by inflammatory processes. Typical trigger factors are periodontal disease, denture pressure sores, and surgical interventions such as tooth extractions. Unfortunately there is only little data on how to proceed with implant therapy in patients with bisphosphonate treatment. This topic is not addressed in the German guidelines on medication-associated osteonecrosis. Therefore a systematic literature review was performed.

Methods

The PICO design was used: (Patients) For which subclientel of patients with antiresorptive therapy (intervention) do dental implants have a benefit (control) compared to forgoing dental implants (outcome) in regards to oral rehabilitation and quality of life without having a substantial risk of BP-ONJ development? A PubMed search was performed including all studies dealing with this topic. Case reports and studies with less than 5 cases were excluded.

Results

There is only very little data available, mostly retrospective case series. 50 articles were analyzed in detail. BP-ONJ can be triggered by dental implants and by dentures in patients with benign and malignant primary diseases. In most studies, analyzing osteoporosis patients only, no cases of BP-ONJ were observed in patients with implant therapy in the time span observed. There are no studies about implant therapy in patients with malignant diseases. Many case series analyzing the trigger factors for BP-ONJ describe dentures as one of the main causes. Perioperative antimicrobial prophylaxis has a benefit in the prevention of BP-ONJ development.

Conclusion

Successful implant therapy is possible in patients receiving antiresorptive therapy. The possibility of osteonecrosis development needs to be explained to the patient. An individual risk assessment is essential, taking the primary disease with the medication and further wound-healing-compromising diseases and medications into account. If possible, bone augmentations should be avoided, and a perioperative antimicrobiological prophylaxis is strongly recommended in these patients.

Assessing the utility of serum C-telopeptide cross-link of type 1 collagen as a predictor of bisphosphonate-related osteonecrosis of the jaw: A systematic review and meta-analysis

BACKGROUND

The authors of this systematic review and meta-analysis assessed the utility of serum C-telopeptide cross-link of type 1 collagen (sCTX), a biomarker of bone resorption, as a predictor of the development of bisphosphonate-related osteonecrosis of the jaw (BRONJ).

TYPES OF STUDIES REVIEWED

The authors searched for studies involving adult participants, written in English, and published through January 20, 2016, using the following electronic databases: the Cochrane Library, MEDLINE via PubMed, and Web of Science. They also searched Google Scholar and the reference lists of all eligible trials and reviews. They identified 16 articles that met their inclusion criteria (9 controlled studies and 7 case series). They applied the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines for systematic reviews and meta-analyses. They independently extracted data in duplicate, including the characteristics of study participants, risk factors, control groups, and outcomes. They assessed risk of bias, and they resolved any disagreements between review authors through discussion.

RESULTS

A meta-analysis with 9 controlled studies revealed no significant difference in mean sCTX values between patients with BRONJ and control participants (difference in means, -31.417; 95% confidence interval [CI], -91.560 to 28.726; P = .306). A second meta-analysis with 4 studies showed no significant difference in risk of having an sCTX value below 150 picograms per milliliter for patients with BRONJ compared with control participants (risk ratio, 1.892; 95% CI, 0.636-5.626; P = .251).

CONCLUSIONS AND PRACTICAL IMPLICATIONS

A systematic review of the literature with meta-analysis does not support the use of sCTX levels as a predictor of the development of BRONJ. Further prospective large sample studies are needed to understand the role of sCTX as a predictor for BRONJ.

Medication Related Osteonecrosis of the Jaw: 2015 Position Statement of the Korean Society for Bone and Mineral Research and the Korean Association of Oral and Maxillofacial Surgeons

Bisphosphonates are the most widely prescribed drugs for the treatment of osteoporosis, and 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 occurrence of osteonecrosis of the jaw (ONJ) could be related with bisphosphonate 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 (ASBMR) and American Association of Oral and Maxillofacial Surgeons (AAOMS) 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 a consideration of the fact that ONJ also occurs for denosumab, a bone resorption inhibitor of the receptor activator of nuclear factor-kappa B ligand (RANKL) antibody family, and bevacizumab, an anti-angiogenesis inhibitor. In 2009, a statement on ONJ was also reported locally by a relevant organization, which has served as basis for clinical treatment in Korea. In addition to the new official stance of the AAOMS and ASBMR, with an increasing pool of ONJ clinical experience, a revised version of the 2009 local statement is needed. As such, the Korean Society for Bone and Mineral Research (KSBMR) and the Korean Association of Oral and Maxillofacial Surgeons (KAOMS) have collectively formed a committee for the preparation of an official statement on MRONJ, and have reviewed recent local and international data to propose guidelines customized for the local Korean situation.

Serum Markers of Bone Turnover and Angiogenesis in Patients With Bisphosphonate-Related Osteonecrosis of the Jaw After Discontinuation of Long-Term Intravenous Bisphosphonate Therapy

PURPOSE

To analyze serum markers of bone turnover, angiogenesis, endocrine function, and inflammation in patients with bisphosphonate-related osteonecrosis of the jaw (BRONJ) who discontinued long-term intravenous bisphosphonate (BP) therapy.

PATIENTS AND METHODS

Serum samples were obtained from 25 BRONJ patients who had discontinued long-term intravenous BP therapy for an average of 11.4 ± 8.7 months and 48 non-BRONJ controls who continued receiving intravenous BP therapy. Samples were analyzed for total alkaline phosphatase, bone-specific alkaline phosphatase, osteocalcin, C-telopeptide, vascular endothelial growth factor, triiodothyronine, thyroxine, thyroid-stimulating hormone, 25-hydroxyvitamin D, and C-reactive protein.

RESULTS

The mean number of BP infusions was significantly higher in BRONJ patients compared with controls (38.4 ± 26.3 infusions vs 18.8 ± 7.2 infusions, P < .0001); however, the duration of BP therapy was not significantly different between the groups (P = .23). Overall, there were no significant differences in any of the markers between BRONJ patients and controls (all P values ≥ .16). In a subgroup analysis that matched BRONJ patients and controls according to mean age and number of BP infusions (10 BRONJ patients and 48 controls), log10 vascular endothelial growth factor (2.9 ± 0.4 pg/mL vs 2.4 ± 0.4 pg/mL, P < .001) and C-reactive protein (34 ± 26 mg/L vs 13 ± 8 mg/L, P < .01) levels were significantly higher in BRONJ patients compared with controls. Within BRONJ patients, none of the serum markers were correlated with duration of BP discontinuation.

CONCLUSIONS

Levels of bone turnover and endocrine markers in BRONJ patients who discontinue long-term intravenous BP therapy are similar to those in non-BRONJ controls receiving intravenous BP therapy. However, levels of angiogenesis and inflammation markers are higher in BRONJ patients who discontinue long-term intravenous BP therapy. The prolonged skeletal half-life of BPs may suppress bone turnover markers in BRONJ patients for several years after discontinuation of intravenous BP therapy, suggesting an extended effect on bone homeostasis.

Bone scintigraphy predicts bisphosphonate-induced osteonecrosis of the jaw (BRONJ) in patients with metastatic castration-resistant prostate cancer (mCRPC)

OBJECTIVES

The aim of this study was to evaluate the role of bone scintigraphy (BS) in early prediction of clinically asymptomatic bisphosphonate (BP)-related osteonecrosis of the jaws (BRONJ) in patients with metastatic castration-resistant prostate cancer (mCRPC).

MATERIAL AND METHODS

BS of mCRPC patients treated with BP was evaluated for pathologic tracer uptake of the jaws in BS suspicious for BRONJ. Results were compared to development of clinically evident BRONJ. Sensitivity, specificity and predictive values of BS for the detection of BRONJ as well as time from beginning of BP therapy to pathologic tracer uptake in BS and time from pathologic tracer uptake in BS to clinically evident BRONJ were determined.

RESULTS

Thirty BP-treated patients were included. Nine patients (30%) had pathologic BS lesions of the jaws. Six patients (20%) developed BRONJ. Sensitivity and specificity of BS for BRONJ prediction were 67 and 79%. Median time from the start of BP treatment to pathologic tracer uptake in BS was 28 months (range 10-33) and from pathologic tracer uptake in BS to clinically evident BRONJ 6.5 months (range 2-19). Pathologic tracer uptake in BS was significantly more often observed in patients who developed BRONJ compared to patients who did not (p = 0.049; OR 7.6).

CONCLUSIONS

Patients with pathologic tracer uptake in the jaws in BS significantly more often develop BRONJ. An unsuspicious BS is predictive for absence of BRONJ in the future.

CLINICAL RELEVANCE

We conclude that when BS has been performed, it should not only be used to assess tumour stage and treatment response but also to check for pathologic tracer uptake in the jaws in BS to detect BRONJ at an early stage in mCRPC patients receiving bisphosphonates.

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.

A C-terminal crosslinking telopeptide test-based protocol for patients on oral bisphosphonates requiring extraction: a prospective single-center controlled study

PURPOSE

Patients undergoing extraction are at risk for bisphosphonate-related osteonecrosis of the jaws (BRONJ). A C-terminal crosslinking telopeptide (CTX) level lower than 150 pg/mL has been suggested as a predictor of BRONJ risk. The authors aimed to increase the precision of estimates of the risk of BRONJ in osteoporosis after extraction and to assess value of CTX testing at extraction time in cases of BRONJ in a large prospective cohort.

PATIENTS AND METHODS

All patients on oral bisphosphonates for osteoporosis referred for extractions over a period of 6.5 years were included in a standard protocol. Pre-extraction fasted CTX levels were obtained. All patients were followed until healing. If the CTX level was lower than 150 pg/mL, they were offered a drug holiday. If they declined, if the CTX level was above 150 pg/mL at baseline, or after the drug holiday, they had extractions performed under local anesthesia. Age-matched controls not on bisphosphonates were identified.

RESULTS

Nine hundred fifty patients had 2,461 extractions. One hundred eighty-one patients had a CTX level lower than 150 pg/mL. Four patients developed BRONJ; all had a CTX level lower than 150 pg/mL. All were on alendronate. The case-control comparison approached significance (<150 pg/mL; P = .073). Alendronate was associated with a low CTX level (P < .05). A CTX level lower than 150 pg/mL had a sensitivity of 100% and specificity of 81%. Bayesian analysis yielded a population expected risk of BRONJ of 0.29% (95% confidence interval, 0.12-0.52); the expected risk was 0.42% for a CTX level lower than 150 pg/mL and 0.13% for a CTX level higher than 150 pg/mL.

CONCLUSION

The risk of BRONJ for patients with osteoporosis on bisphosphonates having extractions is approximately 0.2%. A CTX level lower than 150 pg/mL is sensitive and is associated with an approximately 3-fold greater risk of BRONJ.

Prognosis factors in the treatment of bisphosphonate-related osteonecrosis of the jaw - Prognostic factors in the treatment of BRONJ

Objectives: Bisphosphonate-related osteonecrosis of the jaw (BRONJ) is a relatively rare but serious side effect of bisphosphonate (BP)-based treatments. This retrospective study aimed to investigate the risk factors and predictive markers in cases where patients were refractory to a recommended conservative treatment offered in our hospital. Patients and Methods: This single-center study collated the medical records of all patients treated for BRONJ between 2004 and 2011. A complete medical history, including detailed questionnaires, was collected for all patients, focusing on identifying underlying risk factors, clinical features, location and bone marker levels of BRONJ. Results: The mean BRONJ remission rate was 57.6%, and the median duration of remission was seven months. Eighteen patients (34.6%) had persistent or progressive disease with a recommended conservative treatment for BRONJ. Notably, urinary cross-linked N-terminal telopeptide of type 1 collagen (NTX) levels in those resistant to conservative treatment tended to be lower than in patients that healed well. Conclusions: We confirm that a significant proportion of BRONJ sufferers are refractory to a recommended conservative treatment and find that anticancer drugs, periodontal disease, the level of bone exposure and the dosage of intravenous BPs (e.g. zoledronate) represent specific risk factors in BRONJ that may determine the success of a recommended conservative treatment. Additionally, the NTX levels might be able to be a prognostic factor for the conservative treatment of BRONJ; additional research is necessary.

Key words:Bisphosphonate, osteonecrosis, jaw, prognostic, retrospective.

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.

Osteonecrosis

Osteonecrosis affects younger patients more often than osteoarthritis and has significantly greater long-term morbidity.

Corticosteroids constitute the most common cause of nontraumatic osteonecrosis.

The femoral head is the most common site of osteonecrosis.

Bisphosphonate use is associated with osteonecrosis of the jaw.

The final common pathway in the pathogenesis of osteonecrosis is disruption of blood supply to a segment of bone.

Abnormalities in lipid metabolism, bone homeostasis, regulation of apoptosis, coagulopathies, and oxidative stress may play a role in the pathogenesis of osteonecrosis.

Magnetic resonance imaging is currently the optimal test for early diagnosis and identification of the extent of osteonecrosis.

Nonsurgical treatment of osteonecrosis does not change the natural history of the disease.

Although there are many variations on surgical treatment of femoral head osteonecrosis, most patients eventually require total hip arthroplasty.

Knowledge of risk factors and early detection are crucial to the successful management of osteonecrosis.

Due to the lack of successful treatment options, new modes focus on prevention of osteonecrosis.

Short-term teriparatide therapy as an adjunctive modality for bisphosphonate-related osteonecrosis of the jaws

To review the effect of teriparatide as an adjunctive modality for bisphosphonate-related osteonecrosis of the jaws (BRONJ), we describe a series of cases of teriparatide therapy for the treatment of BRONJ and serial changes of serum osteoclacin (s-OC) and serum C-terminal telopeptide cross-link of type I collagen (s-CTX).

INTRODUCTION

Management of BRONJ is quite challenging and the currently recommended modalities for BRONJ are still suboptimal. For the improvement of bony remodeling, some clinicians advocated bisphosphonate holiday although validity of this drug holiday has been debated so far. Recently, the use of teriparatide was introduced in several cases, but the number of the publication is limited and mostly anecdotal so far.

METHOD

Bisphosphonate was suspended and teriparatide was given to six patients diagnosed with BRONJ by single bone specialist. Medical record review and interviews were carried out. S-CTX and s-OC were measured at the baseline, 2 months and 3 months later teriparatide therapy. The outcome of the treatment and the change of biochemical markers were compared.

RESULT

In all six patients, s-OC values were significantly elevated within 2 months after teriparatide treatment and the BRONJ lesions were healed. S-CTX values were also elevated in four patients, whereas those of the rest two patients stayed within minimal change. The change was marginally significant at 3 months.

CONCLUSION

In terms of the multifactorial etiology of BRONJ, bone formation suppression was noticed in the patients. Based upon this finding, the short-term use of teriparatide might be beneficial to the resolution of BRONJ lesions by improving suppressed bone remodeling.

The role of bone turnover markers in monitoring treatment in postmenopausal osteoporosis

Bone metabolism is assessed using biochemical bone turnover markers (BTM). BTM reflect the metabolic effect of drugs on bone turnover, help to establish the lowest dose inducing the largest change in the BTM, predict treatment-related reduction in fracture risk, and are helpful in bridging studies. Changes in BTM during anti-osteoporotic therapy depend on the cellular mechanism of action of the drug, degree of change in bone turnover rate and route of administration. BTM help to establish the optimal dose of anti-osteoporotic drugs because treatment-related changes in BTM are more rapid compared with change in BMD. A greater decrease in BTM levels during the first year of tantiresorptive treatment is associated with greater antifracture efficacy over 3 years. According to preliminary data, measurement of BTM can improve persistence with anti-resorptive treatment. The use of BTM to monitor anti-osteoporotic therapy in "real life" is limited at this stage.

Osteonecrosis of the jaws in patients treated with bisphosphonates

The literature describes an increasing presence of bisphosphonate-induced osteonecrosis of the jaws (ONJ), characterized by the exposure for over 8 weeks of necrotic bone in the maxillofacial region, after bisphosphonate therapy, in the absence of prior maxillary radiotherapy. The present literature review examines the etiopathogenesis, risk factors, clinical forms, diagnosis, treatment and prevention of bisphosphonate-induced ONJ. In addition, a review is made of all the series involving over 15 patients diagnosed with this disorder between 1 January 2011 and 15 May 2011. A PubMed-Medline search was carried out with the following key words: “bisphosphonates” and “osteonecrosis”. The appearance of osteonecrosis is a serious complication, with an increasing incidence, that affects patient quality of life and causes important morbidity. All patients treated with bisphosphonates are at risk of developing osteonecrosis as a result of such medication. This potential complication therefore should be explained to the patient by both the prescribing physician and the dental surgeon in charge of oral treatment, with the obtainment of informed consent in all cases.

Key words:Osteonecrosis of the jaws, bisphosphonates, etiopathogenesis, prevention, treatment.