Treatment of Medication-Related Osteonecrosis of the Jaws without Segmental Resections: A Case Series

BACKGROUND Medication-related osteonecrosis of the jaw (MRONJ) is a rare but serious reaction to anti-resorptive drugs (ARDs) in patients treated for osteoporosis and conditions related to cancer. Treatment for MRONJ consists of the use of non-operative therapies according to the evolution of the disease, which consist of the use of antimicrobial mouthwashes, systemic antibiotics, and operative therapies, such as debridement of necrotic bone, marginal or segmental resection, and bone reconstruction of the jaws in more advanced stages of the disease. CASE REPORT This is a case series of 11 female patients treated for MRONJ, with a mean age of 76.5 years. Patients with malignant diseases of the jaws or those undergoing head and neck radiotherapy were excluded. Nine patients were medicated for osteoporosis with oral bisphosphonates and denosumab, and 2 patients used zoledronate to treat metastatic breast cancer. MRONJ prevailed in the mandible, most patients were classified as stage 2, and the most frequent triggers were tooth extraction and prosthetic trauma. All patients initially underwent non-operative therapies and were operated according to MRONJ stage, but none required segmental resection. Adjuvant treatments were used in 5 patients, and mean treatment and follow-up periods were 5 and 18.3 months, respectively. There was complete resolution of disease in all patients, with only 1 relapse. CONCLUSIONS This case series suggests that it is possible to treat MRONJ with conservative therapies in the early stages of the disease and minimally invasive surgeries in more advanced stages of the disease, thus avoiding segmental jaw resections.

Rat Calvaria Model Mimicking the Intraoral Lesion of Medication-Related Osteonecrosis in the Jaw: A Preliminary Test

Numerous preclinical intraoral models have been proposed to study medication-related osteonecrosis of the jaws (MRONJ). However, an extraoral animal model is necessary to investigate the effects of interventions such as grafts or direct therapeutics. This study aimed to establish a MRONJ rat model on the calvaria. Seven rats were allocated to either the control or MRONJ group. The MRONJ group received injections of zoledronic acid and dexamethasone to induce osteonecrosis over 4 weeks. Two weeks after these injections, the maxillary first molar was extracted, and two calvaria defects were created using a 4 mm trephine burr. One defect was left untreated, while the other was filled with harvested calvaria bone. A histological examination of all calvaria in the MRONJ group revealed avascular necrosis and the destruction of cortical bone. An independent t-test and Pearson's correlation coefficient were used for statistical analysis and the evaluation of alveolar and calvaria defects. The total alveolar and calvaria defect volume in the control group was significantly smaller than that in the MRONJ group. A statistically significant correlation was observed between alveolar and calvaria defects (Pearson correlation = 0.6, p = 0.023). The autogenous grafts showed poor results in the MRONJ group since they failed to revascularize and exhibited necrosis. The calvaria in this study successfully mimicked MRONJ lesions with avascular necrosis. This preclinical model could be used to develop treatments that are applicable to MRONJ.

A Case Report of Ibandronic Acid Induced Non-Exposed BRONJ Involving the Maxillary Sinus

Background

The aim of this case report is to present an interesting case of bisphosphonate-related osteonecrosis of the jaw, involving the maxilla and the maxillary sinus, as a result of per os administration of ibandronic acid.

Methods

A female patient, 62 years old, was referred to the Department of Dentoalveolar Surgery, Surgical Implantology and Radiology, School of Dentistry, Aristotle University of Thessaloniki, Greece, complaining about pain in the first quadrant. Her medical history revealed per os bisphosphonate administration for the past four years. Subsequently, the cone-beam computed tomography examination revealed a small sequestrum of bone, surrounded by radiolucency, in proximity with the sinus floor. The clinical examination didn't reveal any pathological clinical signs.

Results

Based on the radiological examination, a surgical approach was implemented to remove the necrotic bone, irrigate the alveolar process and the sinus with saline, and finally achieve primary closure, after which, the patient healed uneventfully. The osteonecrosis was attributed to the bisphosphonate administration.

Conclusions

Bisphosphonate-related osteonecrosis of the jaw without obvious or with minor implication of gingival tissues is a diagnostic challenge indicating an early stage of this adverse reaction. Imaging is critical for the early detection of those cases. After careful choice of the case the proper surgical intervention could be effective to eliminate a future advancement of bone destruction. The prevention of osteonecrosis of the jaw can be achieved through the provision of adequate education to dental medicine practitioners, medical doctors, and patients.

Comparison of the Effectiveness of Conservative and Surgical Treatment of Medication-Related Osteonecrosis of the Jaw: a Systematic Review

Objectives

The objective of this systematic review is to evaluate the current knowledge on the effectiveness of conservative and surgical treatment of medication-related osteonecrosis of the jaw.

Material and Methods

MEDLINE (PubMed), ScienceDirect and Cochrane Library search in combination with hand-search of relevant journals was conducted including human studies published in English between January 2017 and February 2023. Studies assessing treatment strategies for medication-related osteonecrosis of the jaw (MRONJ) were included. Quality and risk-of-bias assessment were evaluated by Joanna Briggs Institute (JBI) Risk of Bias tool.

Results

A total of 4227 articles were screened from which 9 studies (7 cohort studies and 2 randomized controlled trials) met the inclusion criteria and were included in the final data synthesis. Two studies evaluate effectiveness of conservative approaches for treating MRONJ, 5 studies evaluate surgical approaches effectiveness, and 2 studies compare between those approaches. The follow-up period ranged from 6 months to 60 months. According to bias assessment, the mean JDI score of the included studies was > 9 ("low risk of bias"). The stage of the disease, the procedure performed on the patient and the results of the treatment were presented.

Conclusions

Surgical therapy seems to be superior to conservative therapy for the management of adverse stages medication-related osteonecrosis of the jaws, while conservative treatment appears to yield good outcomes at asymptomatic patients with early stages of the disease.

Treatment outcomes and time to healing of medication-related osteonecrosis of the jaw based on image findings

OBJECTIVES

This study aimed to evaluate the prognostic treatment outcome of non-operative management of medication-related osteonecrosis of the jaw (MRONJ), particularly regarding the relationship between image findings and treatment outcomes.

METHODS

This single-center, retrospective observational study included patients with MRONJ who were conservatively treated between 2010 and 2020. All patients were evaluated in terms of MRONJ treatment outcomes, time to healing, and prognostic factors, including sex, age, underlying disease, antiresorptive drug type, discontinuation of antiresorptive treatment, chemotherapy, corticosteroid treatment, diabetes mellitus, location of MRONJ, clinical stage of MRONJ, and computed tomography image findings.

RESULTS

The complete healing rate among the patients was 68.5%. Cox proportional hazards regression analysis revealed that "Sequestrum formation" on the internal texture (hazard ratio = 3.66; 95% confidence interval, 1.30-10.29; P =.014) and chemotherapy (hazard ratio = 0.41; 95% confidence interval, 0.18-0.95; P =.037) were significantly associated with treatment outcome. The median time to healing in patients with "Sequestrum formation" on the internal texture (4.4 months) was significantly shorter than the median time to healing in those marked with "Sclerosis" or "Normal" (35.5 months; P <.001) and "Lytic changes with sclerosis" (14.5 months; P =.015).

CONCLUSIONS

The image findings on the internal texture of the lesions at the initial examination and chemotherapy were associated with the treatment outcomes of nonoperative management of MRONJ. The image findings of "Sequestrum formation" were associated with lesions taking a short time to heal and better outcomes, whereas "Sclerosis" and "Normal" were associated with lesions with longer healing times.

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

Objective

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

Methods

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

Results

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

Conclusions

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

High doses of zoledronic acid induce differential effects on femur and jawbone microstructure

OBJECTIVES

The aim of this study is to investigate the long-term effects on jaw and femur bone induced by oncologic doses of zoledronic acid in a young rat model.

MATERIAL AND METHODS

Six 12-week-old male Wistar rats received zoledronic acid (0.6 mg/kg) and six control rats received saline solution in the same volume. Compounds were administered intraperitoneally in five doses every 28 days. Euthanasia was performed 150 days after therapy onset. After animal sacrifice, their mandibles and femurs were scanned ex vivo using a high-resolution (14 μm) micro-computed tomography. Morphometric bone parameters were calculated using CT-Analyzer (Bruker, Belgium) between the first and second mandibular molars and in the distal femur metaphysis and epiphysis.

RESULTS

The treatment group as compared to the controls showed a significantly (p < .05) increased bone quantity (↑BV/TV, ↓Po[Tot], ↑Tb.Th), bone density (↑TMD, ↑BMD), and osteosclerosis of the trabecular bone (↓Tb.Sp, ↓Conn.Dn, ↓Tb.Pf, ↓SMI) in all anatomical sites. Bone remodeling suppression due to zoledronic acid treatment was more pronounced (p < .05) in the femoral metaphysis relative to the mandible and epiphysis. The exploratory linear discriminant analysis showed that for the mandible, it was mainly the bone quantity-related morphometric indices (BV/TV and Tb.Th), while for the femoral epiphysis and metaphysis, it was bone structure-related (Tb.Pf and Tb.N), which are of primary importance to study the treatment effect.

CONCLUSION

High doses of bisphosphonates can differently affect the bone quantity, density, and structure in long bones and jawbones. In the metaphysis, bone changes were primarily concentrated in the region of the growth plate. Future studies may consider the use of bone morphometric indices to evaluate the effect of bisphosphonates.

Volumetric analysis of mandibular lesions with SPECT/CT: a pilot clinical study of maximum standardized uptake value

Purpose

This study was designed to investigate mandibular lesions using volumetric analysis with bone single-photon emission computed tomography/computed tomography (SPECT/CT).

Material and methods

Eight patients with mandibular lesions underwent SPECT/CT scan acquisition 4 hours after injection of Tc-99m hydroxymethylene diphosphonate (HMDP). Regarding volumetric analysis, maximum standar-dized uptake value (SUV) was obtained using software and a workstation (Q.Volumetrix MI and GEniE-Xeleris 4 DR, respectively). The localization and size of the volume of interest (VOI) can be drawn over the lesion, mesial, distal, and opposite side as normal using the CT, SPECT, and SPECT/CT transaxials, coronals, and sagittals as the anatomical reference. Q.Volumetrix MI can analyse SUV of lesions by organ segmentation using optional pan and zoom imaging. Then, the dosimetry software provided multiple quantitative data for a given VOI. Statistical analyses for the maximum SUV were performed by Mann-Whitney U test. A p-value lower than 0.05 was considered as statistically significant.

Results

Maximum SUVs for medication-related osteonecrosis of the jaw (n = 4, 25.4 ± 4.9), chronic osteomyelitis (n = 3, 14.6 ± 3.1), and squamous cell carcinoma (n = 1, 31.7) were significantly higher than those of the opposite side as normal mandible (3.8 ± 0.7, 4.6 ± 1.8, and 7.4, respectively; p = 0.000).

Conclusions

Volumetric analysis with SPECT/CT could be useful for the evaluation of mandibular lesions, such as detecting and surgical planning.

Maximum standardized uptake value of normal structures in the head and neck with bone SPECT/CT

INTRODUCTION

The quantitative parameter was successfully derived from the quantitative bone SPECT/CT images. The aim of this study was to evaluate maximum standardized uptake value (SUV) of normal structures in the head and neck with bone SPECT/CT.

METHODS

Fifty-three patients with jaw lesions (11 chronic osteomyelitis, eight osteoradionecrosis and 34 medication-related osteonecrosis of the jaw) who had bone SPECT/CT were prospectively included. The maximum SUV of normal structures including vertebrae, sternal body, parietal bone and hyoid bone were analysed. Statistical analyses for the maximum SUV were performed by Pearson's rank correlation test. A P value lower than 0.05 was considered statistically significant.

RESULTS

The maximum SUVs of vertebrae, sternal body, parietal bone and hyoid bone of all patients were 8.10 ± 3.72, 5.16 ± 2.05, 3.67 ± 1.55 and 1.44 ± 0.56, respectively. Furthermore, the maximum SUV of vertebrae was significantly correlated with that of sternal body (Y = 0.527X + 5.388 (R²  = 0.084, P = 0.035)).

CONCLUSIONS

Maximum SUV with bone SPECT/CT should be useful for characterization of normal structures in the head and neck. Furthermore, the data reported herein can be used for reference in future studies and in clinical settings for head and neck lesions.

Development and evaluation of the clinimetric properties of the Medication-Related Osteonecrosis of the Jaw Quality of Life Questionnaire (MRONJ-QoL)

The purpose of this study was to develop a self-administered questionnaire (MRONJ-QoL) to assess the quality of life (QoL) of patients with medication-related osteonecrosis of the jaw (MRONJ). A prospective study was performed to develop and evaluate the questionnaire. The MRONJ-QoL was formulated through a review of the literature and interviews of experts and patients. Following development, it was administered to 60 patients with a diagnosis of MRONJ. The sensibility of the questionnaire was assessed by evaluating feasibility (via interviews of patients), face validity (via interviews of patients and experts), and content validity (via evaluation of internal consistency, floor/ceiling effects, and factor analysis). Reliability was evaluated by measuring intra-rater reliability. Construct validity of the questionnaire was evaluated by both cross-sectional and longitudinal comparisons, including comparing scores of the MRONJ-QoL to disease resolution at 6 months. The final MRONJ-QoL questionnaire consisted of 14 questions, demonstrating high internal consistency (Cronbach's alpha of 0.85) and good reliability (weighted kappa score of 0.65). At the 6-month follow-up, disease resolution was found to be significantly associated with improved MRONJ-QoL scores, suggesting validity of the questionnaire (P < 0.01). Therefore, this is a sensible, reliable, and valid questionnaire for evaluating the QoL of patients with MRONJ.

Therapeutic effect of fluvastatin on medication-related osteonecrosis of the jaw

BACKGROUND

Refractory jaw osteonecrosis that occurs in osteoporotic or cancer patients treated with bisphosphonates is called medication-related osteonecrosis of the jaw but its underlying mechanism is unclear. Statins, therapeutic agents for dyslipidemia, lower blood low-density lipoprotein cholesterol. Fluvastatin promotes the healing of tooth extraction sockets and reduces the risk of developing medication-related osteonecrosis of the jaw-like lesions. We used a rat model to investigate whether injecting fluvastatin at extraction sites promoted the healing of medication-related osteonecrosis of the jaw-like lesions.

METHODS

Upper first molars of rats administered zoledronate and dexamethasone for 2 weeks were extracted. Two weeks after tooth extraction, rats with medication-related osteonecrosis of the jaw-like lesions (bone exposure) were included in this study. A single injection of fluvastatin was administered in the vicinity of the medication-related osteonecrosis of the jaw-like onset site in rats.

RESULTS

The distance between the edges of the epithelia, the length of the necrotic bone exposed toward the oral cavity, the area of the necrotic bone, and the necrotic bone ratio were significantly smaller in the fluvastatin-administered group compared with the saline group. A single application of fluvastatin near the site of medication-related osteonecrosis of the jaw onset showed a tendency to close the epithelium, reduce necrotic bone, and form new bone, even when symptoms had already developed.

CONCLUSION

This study suggests that a single topical administration of fluvastatin may be a novel treatment for medication-related osteonecrosis of the jaw.

[Myelodysplastic syndrome, osteoporosis and medication-related osteonecrosis of the jaw: a case report]

Introduction

Medication-related osteonecrosis of the jaw is a frequent collateral effect found in patients under antiresorptive treatments. Malignancies such as multiple myeloma, breast and prostate cancer as well as bone-metabolic disorders such as osteoporosis, lead the indications for these antiresorptive therapies. Even with a low frequency, myelodysplastic syndromes are also entities that have previously been associated with the development of jaw osteonecrosis.

Objective

the aim of this study is to present a case of a 78-year-old male patient with myelodysplastic syndrome and secondary osteoporosis, treated with high-dose Zoledronic Acid and who developed a clinical scenario compatible with medication-related osteonecrosis of the jaw during its evolution.

Methodology

: the case was recorded and treated in the Oral Medicine Department, Facultad de Odontología, Universidad Nacional de Córdoba, during a two-years period with a partial resolution, which recurred fourteen months later, where finally therapeutic success was achieved through a conservative management.

Conclusion

Due to the increasingly use of antiresorptive drugs, the development of jaw osteonecrosis is possible associated with less frequent pathologies, such as myelodysplastic syndrome. Treatment success in these patients depends on interdisciplinary management and a rigorous clinical, medical and dental follow-up.

Clinical profile of individuals with bisphosphonate-related osteonecrosis of the jaw: an integrative review

BACKGROUND

Bisphosphonate-related osteonecrosis of the jaw (BRONJ) is still the most prevalent type of osteonecrosis with clinical relevance. In Brazil, bisphosphonate use is high but there is a lack of epidemiological studies on BRONJ.

OBJECTIVE

To determine the clinical profile of BRONJ in a Brazilian population through an integrative review.

DESIGN AND SETTING

Integrative review of BRONJ in a Brazilian population.

METHODS

Cases and clinical research on Brazilians with BRONJ between 2010 and 2019, indexed in PubMed/MEDLINE, Scopus, Web of Science and LILACS were reviewed. Age, sex, type and time of bisphosphonate intake, administration route, related diseases, region of the BRONJ, diagnostic criteria, staging, triggering factor and type of treatment were analyzed.

RESULTS

Fifteen articles on 128 subjects were included. Most patients were women (82.03%); the mean age was 63 years. Intravenous zoledronic acid was mostly used (62.50%), for breast cancer treatment (46.87%). The main localization of BRONJ was the mandible (54.68%), associated mainly with tooth extractions (45.98%). The diagnostic criteria were clinical (100%) and radiographic (89.06%), mostly in stage II (68.08%). The surgical treatments were sequestrectomy (37.50%) and platelet-rich plasma (PRP) (36.71%). Microbial control was done using chlorhexidine (93.75%) and infection control using clindamycin (53.90%).

CONCLUSIONS

BRONJ had higher prevalence in Brazilian women receiving treatment for breast cancer and osteoporosis. The mandible was the region most affected with a moderate stage of BRONJ, particularly when there were histories of tooth extraction and peri-implant surgery. Sequestrectomy with additional drugs and surgical therapy was the treatment most accomplished.

Endothelial progenitors increase vascularization and improve fibroblasts function that prevent medication-related osteonecrosis of the jaw

OBJECTIVES

In a previous rat model, MRONJ occurrence was 50%. Our aim was to investigate the potential of endothelial progenitor cells (EPCs) to improve fibroblasts function and prevent MRONJ.

METHODS

Human gingival fibroblasts were cultured with EPC-conditioned media (EPC-CM); endothelial growth media (EGM-2) or DMEM followed by incubation with 10 µM zoledronic (ZOL) and dexamethasone (DEX). Cell proliferation and migration were assessed by XTT and scratch wound healing assays. In vivo, ten Lewis rats were treated weekly with ZOL and DEX for 11 weeks. After a week, EPCs or EGM-2 were injected to the gingiva around the molars. At 3 weeks, bilateral molars were extracted. After 8 weeks, wound healing was assessed, and serum VEGF and blood vessels were quantified.

RESULTS

ZOL/DEX significantly reduced fibroblasts proliferation and wound healing. Treatment with EPC-CM before ZOL/DEX improved cell proliferation, and scratch healing (p = .007, p = .023). In vivo, local EPC injection before tooth extraction increased serum VEGF (p = .01) and soft tissue vascularization (p = .05). Normal healing was similar (80%) in EPCs and EGM-2 groups.

CONCLUSION

EPC rescued fibroblasts from the cytotoxic effect of ZOL/DEX and elevated serum VEGF and vessel density that might reduce MRONJ occurrence to 20% compared to 50% in a similar model.

Extracellular Vesicles of Stem Cells to Prevent BRONJ

Extracellular vesicles (EVs), several tens to hundreds of nanometers in size, are vesicles secreted by cells for intercellular communication. EVs released from mesenchymal stem cells (MSC-EVs) have the potential to treat multiple diseases. This study aimed to determine the effects of MSC-EVs on bisphosphonate-related osteonecrosis of the jaw (BRONJ), whose pathogenesis and treatment are not yet established. To this end, zoledronic acid (ZOL) was administered to bone marrow cells and fibroblasts in vitro. In vivo, a BRONJ model was produced by administering ZOL to rats and extracting teeth. Each MSC-EV-treated and nontreated group was compared histologically and molecularly. In vitro, the nontreated group showed an increased number of β-galactosidase-positive cells and expression of senescence-associated genes p21, pRB and senescence-related inflammatory cytokines. Conversely, MSC-EV administration decreased the number of senescent cells and expression levels of p21, pRB and inflammatory cytokines. In vivo, in the nontreated group, the socket was partially uncovered by the oral epithelium, leaving an exposed bone. Conversely, in the MSC-EV-treated group, the socket was healed. Besides, in the nontreated group, β-galactosidase-positive cells existed in the socket and colocalized with the CD90 and periostin-positive cells. However, there were few β-galactosidase-positive cells in the MSC-EV-treated group. Furthermore, gene expression of stem cell markers Bmi1 and Hmga2 and the vascular endothelial marker VEGF was significantly increased in the MSC-EV-treated group, compared with that in the nontreated group. These results indicate that MSC-EVs prevent ZOL-induced senescence in stem cells, osteoblasts, and fibroblasts and reduce inflammatory cytokines. Furthermore, administration of MSC-EVs prevented senescence of cells involved in wound healing and the spread of chronic inflammation around senescent cells, thereby promoting angiogenesis and bone regeneration and preventing BRONJ.

Aminobisphosphonate-treated ewes as a model of osteonecrosis of the jaw and of dental implant failure

BACKGROUND

Bisphosphonate (BP)-related osteonecrosis of the jaw (BRONJ) and dental implant failure are two negative side effects of chronic aminoBP treatment.

METHODS

Eleven ovariectomized (OVX) ewes and four ewes subjected to sham surgery (SHAM) were treated as follows: OVX (n = 5): OVX plus saline solution; zoledronic acid-treated group (ZOL) (n = 6): OVX plus ZOL; SHAM (n = 4): SHAM plus saline solution. Extraction of the first upper molar was performed at 1 year, dental implant placement at 2 years, and sacrifice at 28 months.

RESULTS

Implants remained in place in SHAM and OVX ewes but were lost in all ZOL ewes. ZOL sheep (2/6) showed inflammation and necrotic bone at mandibular region. No differences in serum calcium (Ca), inorganic phosphate (Pi) or 25-hydroxyvitamin D were observed, whereas bone alkaline phosphatase levels decreased in the three studied groups (P < 0.05). The significantly lowest levels of carboxy-terminal telopeptide of type I collagen were observed in ZOL (P < 0.05), and showed no differences between SHAM and OVX. OVX showed the lowest and ZOL the highest Ca and Pi contents in femur and maxilla (P < 0.05). Bone volume (BV/TV%) and iliac crest were similar at baseline and at month 4. At the end of the study, BV/TV%, proximal femur and hemi-mandible bone mineral content and bone mineral density, and trabeculae number were similar in SHAM and ZOL, and lower in OVX (P < 0.05).

CONCLUSION

All ZOL-treated ewes on a schedule similar to that used in cancer patients showed extensive suppression of bone remodeling and implant failure. Some of the ZOL ewes developed BRONJ.

Immediate hyperbaric oxygen after tooth extraction ameliorates bisphosphonate-related osteonecrotic lesion in rats

BACKGROUND

This study aims to assess whether hyperbaric oxygen (HBO) applied immediately after tooth extraction could ameliorate medication-related osteonecrosis of the jaw in rats.

METHODS

To evaluate whether osteonecrosis could be successfully induced, healing of extraction maxillary molars was examined in 40 female Sprague Dawley rats received zoledronic acid (7.5 µg/kg) plus dexamethasone (1 mg/kg). Rats were divided into four groups, receiving zero, two, four, or seven injection(s) for 7 days, respectively. Effect of HBO, pressurized to 2.5 atmospheres absolute (ATA) at rate of 0.15 ATA/min with 100% oxygen for 90 minutes, applied immediately after tooth extraction, on the development of osteonecrosis was evaluated. Lesions among groups were compared by size of ulceration, exact area (mm² ) or relative area (%), and by histology.

RESULTS

Unhealed ridge was observed in all nine rats in four and seven injection groups, but none of 10 rats in the control (non-injection) group. Immediate HBO significantly reduced the lesions in rats that received four injections, regardless of the distribution and the total/relative areas of lesions (P <0.01). Histological findings showed the lesions were uncovered epithelium and severe tissue inflammation.

CONCLUSION

This is the first in vivo study demonstrating the HBO applied immediately after tooth extraction effectively decreases the development of medication-related osteonecrosis.

ACE Gene Variant Causing High Blood Pressure May Be Associated With Medication-related Jaw Osteonecrosis

The association of the high blood pressure D variant of the angiotensin-converting enzyme (ACE) gene with medication-related jaw osteonecrosis (MRONJ) is described in two Greek patients. The first patient, a 73-year-old man, took zolendronate, 4 mg/100 ml IV once per month for two years for prostate cancer and bone metastases. Three months after drug discontinuation, extraction of the first premolar was performed. After the intervention, he suffered from osteonecrosis of the mandible. He presented with hypertension and genetic testing revealed that he was homozygous for the high blood pressure D variant of the ACE gene. The second patient, a 65 years old woman, took denosumab, 120 mg subcutaneously once per month for 6 months for possible bone metastases from breast cancer. Three months after extraction of the first molar, she suffered from MRONJ. He also presented with hypertension and genetic testing revealed that she had the high blood pressure D variant of the ACE gene in a heterozygous state, which moderately predisposes to hypertension. To our knowledge, this is the first report indicating that genetic predisposition to hypertension may increase risk for MRONJ.

Nitrogen-containing bisphosphonate therapy-Part II: Assessment of alveolar bone tissue inflammatory response in rats-A blind randomized controlled trial

This study aimed to evaluate the alveolar bone tissue inflammatory response in rats undergoing zoledronic acid therapy. The study sample was composed of 28 Wistar rats. Animals from the test group GTa received a weekly intraperitoneal dose of 0.2 mg/kg of zoledronic acid for 3 weeks, while test group GTb received the same dose for 8 weeks. A physiological saline dose, equivalent to that of the medication, was administered to the controls in groups GCa and GCb. A defect was created in the dental crown of the lower first molars using a drill to simulate pulp and periapical injury. Data were evaluated regarding image grey levels by cone-beam computed tomography and histologically by assigning scores for the presence of inflammatory infiltrate, type of infiltrate, vascularization, bone necrosis and dental resorption. Grey levels in the 3-week therapy group (GTa) showed more pronounced changes in comparison with those seen in the GCa group (P < 0.05). Evaluation of the scores demonstrated no association between any of the variables amongst the groups (>0.05). However, bone remodelling decreased in the groups receiving the medication. Bone necrosis was present more frequently in group GTb than in the control group GCb. The results suggest that the drug interfered in the reaction capacity of the alveolar bone tissue as test group GTa showed higher grey levels in comparison to the control group GCa. In addition, there was less bone remodelling activity, with the appearance of bone necrosis zones and intense acute inflammatory infiltrate associated with the 8-week therapy group GTb.

Dental Implant Placement in Patients on Bisphosphonate Therapy: a Systematic Review

Objectives

The review aims to study dental implant placement purposefulness for patients who have been treated or are on treatment with bisphosphonate medication.

Material and Methods

Structured search strategy was applied on electronic databases: MEDLINE, PubMed, PubMed Central and ResearchGate. Scientific publications in English between 2006 and 2017 were identified in accordance with inclusion, exclusion criteria. Publication screening, data extraction, and quality assessment were performed. Outcome measures included implant failure or implant-related osteonecrosis of the jaw.

Results

In total, 32 literature sources were reviewed, and 9 of the most relevant articles that are suitable to the criteria were selected. Heterogeneity between the studies was found and no meta-analysis could be done. Five studies analysed intraoral bisphosphonate medication in relation with implant placement, three studies investigated intravenous bisphosphonate medication in relation with implant placement and one study evaluated both types of medication given in relation with implant placement. Patients with intraoral therapy appeared to have a better implant survival (5 implants failed out of 423) rate at 98.8% vs. patients treated intravenously (6 implants failed out of 68) at 91%; the control group compared with intraoral bisphosphonate group appeared with 97% success implant survival rate (27 implants failed out of 842), showing no significant difference in terms of success in implant placement.

Conclusions

Patients treated with intravenous bisphosphonates seemed to have a higher chance of developing implant-related osteonecrosis of the jaw. The intraorally treated patient group appeared to have more successful results. Implant placement in patients treated intraorally could be considered safe with precautions.

Effectiveness of treatments for medication-related osteonecrosis of the jaw: A systematic review and meta-analysis

BACKGROUND

The effectiveness of management strategies used for the treatment of medication-related osteonecrosis of the jaw (MRONJ) remains poorly understood. The authors evaluated systematically the effectiveness of the various treatment modalities used for MRONJ.

TYPES OF STUDIES REVIEWED

The authors conducted a comprehensive search of MEDLINE, Embase, the Cochrane Library, and Scopus to identify randomized controlled trials, nonrandomized controlled trials, and prospective cohort studies to evaluate comparatively the effectiveness of management strategies for the treatment of MRONJ. The authors conducted the identification of eligible studies in duplicate and synthesized the extracted data by means of a meta-analysis, when feasible.

RESULTS

The authors found 13 studies with a medium-to-high risk of bias that met the inclusion criteria of this review. The authors found that, compared with medical treatment of local antimicrobials with or without systemic antimicrobials, the study investigators associated surgical treatment with higher odds of complete resolution of the condition (2 studies; 76 participants; unadjusted odds ratio, 3.55; 95% confidence interval, 1.12 to 11.19). The effectiveness of other therapies, such as bisphosphonate drug holidays, teriparatide, and hyperbaric oxygen, was uncertain.

CONCLUSIONS AND PRACTICAL IMPLICATIONS

On the basis of the results of an unadjusted analysis, the results of the studies that were deemed to be medium to low quality and to have medium-to-low statistical power suggested that there are higher odds of resolving MRONJ with surgical treatment compared with medical treatment. High-quality research is required for conclusive statements to be made regarding treatment strategies for management of MRONJ.

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Microscopic Evaluation of the Effect of Oral Microbiota on the Development of Bisphosphonate-Related Osteonecrosis of the Jaws in Rats

Objectives

Osteonecrosis of the jaws is a side effect associated with the use of bisphosphonates. Using histologic analysis, this study aimed to evaluate the influence of microbial colonies in the development of osteonecrosis in the jaws of rats subjected to nitrogenous and non-nitrogenous bisphosphonates, undergoing surgical procedures.

Material and Methods

Thirty-four rats (Rattus norvegicus, Wistar strain) were allocated randomly into three groups: 12 animals treated with zoledronic acid; 12 animals treated with clodronate; and 10 animals treated with saline. Sixty days after the start of treatment, the animals underwent three extractions of the upper right molars. After 120 days of drug administration, the rats were killed. Histologic analysis was performed on specimens stained with hematoxylin and eosin by the technique of manual counting points using Image-Pro Plus software on images of the right hemimaxilla.

Results

Osteonecrosis was induced in the test groups. There was no statistically significant association between the presence of microbial colonies and the presence of non-vital bone (Kruskal-Wallis, P > 0.05).

Conclusions

Use of zoledronic acid was associated with non-vital bone and the results suggested that the presence of microbial colonies does not lead to osteonecrosis.

Immune cellular profile of bisphosphonate-related osteonecrosis of the jaw

OBJECTIVES

Characterize the cell profile and immunostaining of proinflammatory markers in an experimental model of bisphosphonate-related osteonecrosis of the jaw (BRONJ).

MATERIALS AND METHODS

Male Wistar rats (n = 6-7) were treated chronically with saline solution or zoledronic acid (ZA) at 0.04, 0.20, and 1.00 mg kg(-1) (1.4 × 10(-7) , 6.9 × 10(-6) , and 3.4 × 10(-5)  mol kg(-1) ), and subsequently, the first left inferior molar was extracted. Were performed counting of viable and empty osteocyte lacunae, viable and apoptotic osteoclasts, polymorphonuclear neutrophil, mast cells (toluidine blue), and the positive presence cells for CD68, tumor necrosis factor-alpha (TNF-α), IL (interleukin)-1β, inducible nitric oxide synthase (iNOS), nuclear factor-kappa B (NF-kB) and IL-18 binding protein (IL-18 bp).

RESULTS

BRONJ was showed in ZA treated with 0.20 and 1.00 mg kg(-1) . There is a dose dependent increase in percentage of empty osteocyte lacunae (P < 0.001) and apoptotic osteoclasts (P < 0.001), counting of total osteoclasts (P = 0.003), polymorphonuclear neutrophil cells (P = 0.009), cytoplasmic-positive cells of CD68 (P < 0.001), TNF-α (P = 0.001), IL-1β (P = 0.001), iNOS (P < 0.001), NF-kB (P = 0.006), and nuclear-positive cells of NF-kB (P = 0.011). Consequently, there is no difference in mast cells (P = 0.957), and IL-18 bp immunostaining decreases dose dependently (P = 0.005).

CONCLUSIONS

BRONJ is characterized by increases in immunostaining for proinflammatory markers and NF-kB and inversely associated with cells exhibiting IL-18 bp.

Evaluation of BP-ONJ in osteopenic and healthy sheep: comparing ZTE-MRI with µCT

OBJECTIVES

Bisphosphonate-associated osteonecrosis of the jaw (BP-ONJ) is a side effect of antiresorptive treatment that is increasingly prescribed for patients with osteoporosis or malignant diseases with bone metastases. Surgical treatment of BP-ONJ requires adequate pre-operative imaging. To date, CT is the imaging standard in clinical routine; however, defining the extent of the pathological area is difficult and soft tissues are poorly displayed. MRI with zero echo time (ZTE-MRI) to display hard tissues enables a precise display of calcified structures and soft tissues for the delineation of bone necrosis and soft-tissue reactions.

METHODS

BP-ONJ was induced in eight sheep by extraction of two premolars in the left mandible and zoledronate (ZOL) administration. Eight sheep without ZOL administration served as the control group. Four sheep of each main group underwent osteopenia induction via ovariectomy, glucocorticoid administration and a calcium-free diet. After sacrifice, the area of tooth extraction was harvested and scanned with micro-CT (µCT) and ZTE-MRI. Two trained dentists analyzed digital imaging and communications in medicine data sets using three-dimensional imaging software. The periosteal reaction and the remaining extraction sockets were measured.

RESULTS

BP-ONJ was evident, and the remaining extraction sockets were observed in all animals treated with ZOL. Periosteal reactions were more pronounced in animals treated with ZOL, and they appeared broader in ZTE-MRI.

CONCLUSIONS

BP-ONJ lesions in the sheep mandible can be detected using µCT and ZTE-MRI. Although illustration of sequester was more consistent using the µCT, ZTE-MRI was advantageous in evaluation of periosteal reaction.

Nitrogen-containing bisphosphonate therapy: assessment of the alveolar bone structure in rats - a blind randomized controlled trial

This study aimed to assess the effect of zoledronic acid exposure on structures of the alveolar bone of rats. The sample was composed of 42 male Wistar rats. Animals in the T1 and T2 groups received weekly doses of 0.2 mg/kg intraperitoneal zoledronic acid for 3 weeks, while animals in the T3 group received the same treatment for 8 weeks. The control groups C1, C2 and C3 received equivalent doses of saline. The first upper molars of Wistar rats in the C2, T2, C3 and T3 groups were extracted. Cone-beam computerized tomography scans were performed, and the image density was analysed by grey levels. The presence and type of inflammatory infiltrate, vascularization and bone necrosis were assigned by histological qualitative scores. Histomorphometric analysis of bone density was performed in the groups without extraction. No significant differences were found in the bone grey density estimated by grey-level value and histomorphometric analysis between the C1 and T1 groups (P > 0.05). The grey levels in the T3 group were lower (P < 0.05) than in the C3 group, corresponding to the bone defect. Histological assessments showed the presence of bone necrosis in the T3 group and lower levels of bone remodelling in the test groups (T2 and T3) compared to the control groups (C2 and C3). The results of qualitative analyses did not differ significantly between the groups (P > 0.05). Zoledronic acid-exposed animals showed maxillary changes including reduced grey levels, the presence of bone necrosis and a higher prevalence of inflammatory signs.

Effects of a low-level diode laser on oral keratinocytes, oral fibroblasts, endothelial cells and osteoblasts incubated with bisphosphonates: An in vitro study

Bisphosphonate-associated osteonecrosis of the jaw may have multiple causes, including altered bone remodeling, angiogenesis inhibition and impact of bisphosphonate on the soft tissues. Successful treatment is difficult. As a positive effect of low-level laser application on wound healing is well known, an in vitro study was designed to analyze the effect of low-level laser (280 mW, 670 nm) treatment on keratinocytes, fibroblasts, endothelial cells and osteoblasts treated with clodronate, ibandronate, pamidronate or zoledronate. Pure irradiation had a positive effect on cell viability, whereas bisphosphonate treatment had a negative impact. Viability was significantly increased in cells treated with bisphosphonates and sequel irradiation. There was no effect when the bisphosphonate medium was irradiated. The revealed effect of laser stimulation on cell viability is not due to an inactivation of the bisphosphonates. These results may support the idea of low-level laser therapy as a supportive therapy in patients receiving bisphosphonates to prevent and treat bisphosphonate-associated osteonecrosis of the jaw.

Early effects of parathyroid hormone on bisphosphonate/steroid-associated compromised osseous wound healing

SUMMARY

Administration of intermittent parathyroid hormone (PTH) promoted healing of tibial osseous defects and tooth extraction wounds and prevented the development of necrotic lesions in rats on a combined bisphosphonate and steroid regimen.

INTRODUCTION

Osteonecrosis of the jaw (ONJ) has emerged in association with antiresorptive therapies. The pathophysiology of ONJ is unknown and no established cure currently exists. Our objective was to determine the effect of intermittent PTH administration on early osseous healing in the jaw and long bones of rats receiving bisphosphonate and steroid treatment.

METHODS

Ovariectomized rats received the combination therapy of alendronate and dexamethasone (ALN/DEX) for 12 weeks. Osseous wounds were created in the jaw and tibia. PTH was administered intermittently and healing at 2 weeks post-op was compared between the jaw and tibia by microcomputed tomography and histomorphometric analyses.

RESULTS

ALN/DEX treatment was associated with necrotic open wounds in the jaw but had no negative effects on healing and promoted bone fill in tibial defects. PTH therapy prevented the development of necrotic lesions in the jaw and promoted healing of the tibial defects. PTH therapy was associated with the promotion of osteocyte survival in osseous wounds both in the jaw and tibia.

CONCLUSIONS

Wound healing was impaired in the jaw in rats on a combined bisphosphonate and steroid regimen, and PTH therapy rescued necrotic lesions. These findings suggest that PTH therapy could be utilized to prevent ONJ from occurring in patients on combination antiresorptive and steroid therapy.

Teriparatide and the treatment of bisphosphonate-related osteonecrosis of the jaw: a rat model

OBJECTIVES

The objectives of this study were to establish a bisphosphonate-related osteonecrosis of the jaw (BRONJ) rat model and to analyse the effects of teriparatide (TP) on this model.

METHODS

Sprague-Dawley rats were divided into three groups: I-zoledronic acid (ZA, n = 10); II-ZA and teriparatide (ZA + TP, n = 10); III-control (n = 10). Osteonecrosis was induced by administering zoledronic acid to groups ZA and ZA + TP. A week after the injections, rats underwent extraction of the first left mandibular molar. Following a four week period, TP was administered to the ZA + TP group for 28 days. Upon killing, extraction sockets were examined clinically, radiologically and histopathologically.

RESULTS

Clinical examination revealed necrotic bone exposure in none of the animals. MicroCT (µCT) examination showed that bone mineral density of the newly formed bone in the extraction socket was lower in the ZA group than in the ZA + TP group (p < 0.05). Histopathological examination revealed that only the ZA and ZA + TP groups developed osteonecrosis, and the osteonecrotic bone area in the ZA group was larger than that in the ZA + TP group (p < 0.05). Tartrate-resistant acid phosphatase (TRAcP) enzyme histochemistry revealed that the number of detached and large osteoclasts were higher in the ZA group than in other groups, whereas the number of apoptotic osteoclasts in both ZA and ZA + TP groups were higher than in the control group (p < 0.05).

CONCLUSIONS

Our data indicate that bisphosphonate-related osteonecrosis of the jaw model used in the present study is an attractive model to investigate treatment modalities and that TP might be an effective treatment in BRONJ.

Validity of an algorithm to identify osteonecrosis of the jaw in women with postmenopausal osteoporosis in the Danish National Registry of Patients

BACKGROUND

Osteonecrosis of the jaw (ONJ) is an adverse effect of drugs that suppress bone turnover - for example, drugs used for the treatment of postmenopausal osteoporosis. The Danish National Registry of Patients (DNRP) is potentially valuable for monitoring ONJ and its prognosis; however, no specific code for ONJ exists in the International Classification of Diseases 10th revision (ICD-10), which is currently used in Denmark. Our aim was to estimate the positive predictive value (PPV) of an algorithm to capture ONJ cases in the DNRP among women with postmenopausal osteoporosis.

METHODS

We conducted this cross-sectional validation study in the Central and North Denmark Regions, with approximately 1.8 million inhabitants. In total, 54,956 women with postmenopausal osteoporosis were identified from June 1, 2005 through May 31, 2010. To identify women potentially suffering from ONJ, we applied an algorithm based on ICD-10 codes in the DNRP originating from hospital-based departments of oral and maxillofacial surgery (DOMS). ONJ was adjudicated by chart review and defined by the presence of exposed maxillofacial bone for 8 weeks or more, in the absence of recorded history of craniofacial radiation therapy. We estimated the PPV for the overall algorithm and for each separate ICD-10 code used in the algorithm.

RESULTS

Charts were obtained and reviewed for all 60 women with an ICD-10 code potentially representing ONJ. Nineteen potential ONJ cases were confirmed, corresponding to an overall PPV of 32% (95% confidence interval: 20%-45%).

CONCLUSION

Among women with postmenopausal osteoporosis, only about one-third of the potential ONJ cases identified by our ICD-10 based algorithm were confirmed by medical chart review, despite the restriction to patients treated at DOMS. To capture true ONJ cases among women with postmenopausal osteoporosis, alternative approaches are needed.

Evaluation of an algorithm ascertaining cases of osteonecrosis of the jaw in the Swedish National Patient Register

BACKGROUND

Osteonecrosis of the jaw (ONJ) is a medical condition associated with antiresorptive drugs, among others, used to treat osteoporosis and bone metastasis. Currently, there is no consensus regarding the definition of ONJ, and no ONJ-specific International Classification of Diseases-10 code exists. Therefore, register-based studies of this condition may be troublesome.

PURPOSE

To evaluate an algorithm ascertaining ONJ cases in an attempt to facilitate future assessments of ONJ in clinical and epidemiological studies.

METHODS

By means of the Patient Register and the Prescribed Drug Register, we identified all postmenopausal female residents in Sweden from 2005 through 2009. To identify potential cases of ONJ, we employed an algorithm including the following conditions: periapical abscess with sinus, inflammatory conditions of jaws, alveolitis of jaws, idiopathic aseptic necrosis of bone, osteonecrosis due to drugs, osteonecrosis due to previous trauma, other secondary osteonecrosis, other osteonecrosis, and unspecified osteonecrosis. Women seen at departments of oral and maxillofacial surgery, with at least one of the conditions, were classified as potential cases of ONJ. Conditions in anatomic sites other than the jaw were excluded. Validation was performed through medical record review. Case confirmation was based on the ONJ definition by the American Association of Oral and Maxillofacial Surgeons. The algorithm was evaluated by positive predictive values (PPVs) stratified by diagnosis.

RESULTS

For the 87 potential cases identified through our algorithm, the medical records were obtained for 83. The overall PPV was 18% (95% confidence interval (CI) 10%-28%). The highest PPV was observed in osteonecrosis due to drugs (83%, 95% CI 36%-100%). Several diagnoses had a PPV of 0 or were not used at all (periapical abscess with sinus, alveolitis of jaws, idiopathic aseptic necrosis of bone, osteonecrosis due to previous trauma, other secondary osteonecrosis, other osteonecrosis, and unspecified osteonecrosis).

CONCLUSION

It was possible to ascertain cases of ONJ from the Swedish registers using this algorithm; however, the PPV was low. Thus, further refinements of the algorithm are necessary.

Bisphosphonate-associated osteonecrosis of the jaw: are we dealing with a localized non-traditional calciphylaxis?

The bisphosphonate (BP) family of drugs has been used as a vital component in cancer therapy and many other diseases. One of the main adverse effects related to (BP) is BP-associated osteonecrosis of the jaw (ONJ). Although this condition was first recognized in 2003, the pathophysiologic mechanism remains undefined. Our hypothesis is that ONJs clinical course and delayed wound healing is in part correlated to a localized non-traditional calciphylaxis. This effect is identified by the evidence of calcium deposition in the connective tissue and around small blood vessels in the soft tissues immediately adjacent to ONJ lesions. This phenomenon helps to fill gaps in the cascade of events which leads to soft tissue ischemia, necrosis, and non-healing ONJ lesions. Our finding adds to the current knowledge of the potential pathophysiologic mechanisms related to ONJ.