Primary wound closure after tooth extraction for prevention of medication-related osteonecrosis of the jaw in patients under denosumab

A Systematic Review of Laser Photobiomodulation Dosimetry and Treatment Protocols in the Management of Medications-Related Osteonecrosis of the Jaws: A Rationalised Consensus for Future Randomised Controlled Clinical Trials

Medication-related osteonecrosis of the jaw (MRONJ) is a debilitating adverse effect of bisphosphates, antiresorptive therapy or antiangiogenic agents that can potentially increase oxidative stress, leading to progressive osteonecrosis of the jaws. Despite the large number of published systematic reviews, there is a lack of potential MRONJ treatment protocols utilising photobiomodulation (PBM) as a single or adjunct therapy for preventive or therapeutic oncology or non-oncology cohort. Hence, this systematic review aimed to evaluate PBM laser efficacy and its dosimetry as a monotherapy or combined with the standard treatments for preventive or therapeutic approach in MRONJ management. The objectives of the review were as follows: (1) to establish PBM dosimetry and treatment protocols for preventive, therapeutic or combined approaches in MRONJ management; (2) to highlight and bridge the literature gaps in MRONJ diagnostics and management; and (3) to suggest rationalised consensus recommendations for future randomised controlled trials (RCTs) through the available evidence-based literature. This review was conducted according to the PRISMA guidelines, and the protocol was registered at PROSPERO under the ID CRD42021238175. A multi-database search was performed to identify articles of clinical studies published from their earliest records until 15 December 2023. The data were extracted from the relevant papers and analysed according to the outcomes selected in this review. In total, 12 out of 126 studies met the eligibility criteria. The striking inconsistent conclusions made by the various authors of the included studies were due to the heterogeneity in the methodology, diagnostic criteria and assessment tools, as well as in the reported outcomes, made it impossible to conduct a meta-analysis. PBM as a single or adjunct treatment modality is effective for MRONJ preventive or therapeutic management, but it was inconclusive to establish a standardised and replicable protocol due to the high risk of bias in a majority of the studies, but it was possible to extrapolate the PBM dosimetry of two studies that were close to the WALT recommended parameters. In conclusion, the authors established suggested rationalised consensus recommendations for future well-designed robust RCTs, utilising PBM as a monotherapy or an adjunct in preventive or therapeutic approach of MRONJ in an oncology and non-oncology cohort. This would pave the path for standardised PBM dosimetry and treatment protocols in MRONJ management.

Platelet-Rich Fibrin Treatment Evaluation in Patients with Medication-Related Osteonecrosis of the Jaw and Osteoradionecrosis

Background. Medication-related osteonecrosis of the jaw (MRONJ) and osteoradionecrosis (ORN) are associated with severe disability and continuous pain, both of which are very difficult to control. This study aims to evaluate the outcome of platelet-rich fibrin (PRF) treatment compared to iodoform gauze packing and the primary suture of oral mucosa in patients with both MRONJ and ORN. Methods. Patients suffering from MRONJ and ORN who were treated in the Oral and Maxillofacial Surgery Clinic of Cluj-Napoca in the last 10 years were selected for this study from the hospital database. Results. PRF treatment proved to be a reliable method to help heal the necrotic bone sites. High-ASA risk patients and immunosuppressed patients are more prone to recurrence and persistent signs and symptoms. Intravenous bisphosphonates produce more intense symptomatology compared to oral administration. The posterior mandible is more difficult to treat compared to other sites. Conclusions. The quality of life of MRONJ and ORN patients may be improved by a protocol that reduces pain and hospitalization.

The role of leukocyte and platelet-rich fibrin in the prevention of medication-related osteonecrosis of the jaw, in patients requiring dental extractions: an observational study

PURPOSE

Medication-related osteonecrosis of the jaw (MRONJ) is a significant complication which can present following a dental extraction in patients receiving anti-resorptive and anti-angiogenic medications. The purpose of this study was to investigate the possible beneficial effect of L-PRF in the prevention of MRONJ in patients receiving these medications and requiring dental extractions.

METHODS

Thirty-nine patients were included and divided into two groups, depending on whether L-PRF was used after the required dental extraction or not. Subsequently, the patients were categorised into low and high-risk for developing MRONJ, as recommended by the SDCEP guidance.

RESULTS

None of the patients in the L-PRF group returned with established MRONJ. Five high-risk patients in the control group presented with established MRONJ in the follow-up appointment. A significant statistical difference (p = 0.04) was observed following a comparison of the high-risk patients of the two groups.

CONCLUSION

These encouraging results suggest that L-PRF may be useful in the prevention of MRONJ following a dental extraction especially in patients of the higher risk category. A protocol for the management of this type of patients is also introduced.

Comparison of Different Antibiotic Regimes for Preventive Tooth Extractions in Patients with Antiresorptive Intake-A Retrospective Cohort Study

In the present study, the impacts on success rates between three different antibiotic regimes in patients receiving preventive tooth extraction during/after antiresorptive treatment were compared. For the retrospective analysis, we enrolled patients who had undergone tooth extraction from 2009 to 2019 according to the specified preventive conditions under antiresorptive therapy. Three antibiotic regimens were distinguished: (Group 1) intravenous for 7 days, (Group 2) oral for 14 days, and (Group 3) oral for 7 days of application. The primary endpoint was the occurrence of medication-related osteonecrosis of the jaw at 12 weeks after surgery. A total of 760 patients and 1143 extraction regions were evaluated (Group 1 n = 719; Group 2 n = 126; Group 3 n = 298). The primary endpoint showed no significant difference in the development of medication-related osteonecrosis of the jaw between the groups studied (Group 1 n = 50/669 (7%); Group 2 n = 9/117 (7%); Group 3 n = 17/281 (6%); p = 0.746). Overall, the success rate was 93% after intervention when preventive measures were followed. With the same success rate, a reduced, oral administration of antibiotics seems to be sufficient regarding the possible spectrum of side effects, the development of resistance and the health economic point of view.

Low-level laser therapy prevents medication-related osteonecrosis of the jaw-like lesions via IL-1RA-mediated primary gingival wound healing

BACKGROUND

Medication-related osteonecrosis of the jaw (MRONJ) is a serious debilitating disease caused by anti-resorption and anti-angiogenesis drugs, significantly affecting patients' quality of life. Recent studies suggested that primary gingival wound healing may effectively prevent the development of MRONJ. This study aimed to evaluate the effects of low-level light therapy (LLLT) on promoting gingival wound healing in extraction sockets of MRONJ-like mice and preventing the occurrence of MRONJ. Furthermore, we explored underlying mechanisms.

METHODS

Mice were randomly divided into the Ctrl, Zol, and Zol + LLLT groups. Administration of zoledronate and tooth extraction of bilateral maxillary second molars were used to build the MRONJ model, and LLLT was locally administered into the tooth sockets to examine the effect of LLLT. Next, to explore the function of IL-1RA, we performed LLLT with interleukin-1 receptor antagonist (IL-1RA) neutralizing antibody (named Zol + LLLT + IL-1RA NAb group) or negative control antibodies for tooth extraction in subsequent rescue animal experiments. Stereoscope observations, micro-computed tomography, and histological examination were conducted to evaluate gingival wound healing and bone regeneration in tooth sockets. The effects of LLLT on the migration capacities of zoledronate-treated epithelial cells were assessed in vitro.

RESULTS

LLLT promoted primary gingival wound healing without exposed necrotic bone. Micro-computed tomography results showed higher bone volume and mineral density of the tooth sockets after LLLT. Histology analysis showed complete gingival coverage, obvious bone regeneration, and reduced soft tissue inflammation, with down-regulated pro-inflammation cytokines, like interleukin-1 beta (IL-1β) and tumor necrosis factor-α (TNF-α), and up-regulated IL-1RA expression in the gingival tissue in the LLLT group. The rescue assay further showed that the effects of LLLT promoting gingival wound healing and preventing MRONJ might be partially abolished by IL-1RA neutralizing antibodies. In vitro studies demonstrated that LLLT accelerated zoledronate-treated epithelial cell migration.

CONCLUSIONS

LLLT might promote primary gingival wound healing and contribute to subsequent bone regeneration of the tooth extractions in MRONJ-like lesions via IL-1RA-mediated pro-inflammation signaling suppression.

Osteonecrosis of the jaw in primary dental care: Recognition and referral

Osteoradionecrosis (ORN) and medication-related osteonecrosis of the jaw (MRONJ) are uncommon conditions, however when present they have a significant impact on a patient's quality of life and are notoriously difficult to treat. With medical advances resulting in improved survival rates and increased life expectancy, it is likely that general dental practitioners (GDPs) will more frequently be involved in the oral health management of patients at risk of both ORN and MRONJ. Though management of both diseases is beyond the scope of primary care dentistry, the GDP still has a key role in the patient's overall care. It is therefore important to have a good understanding of these conditions and their consequences for dental treatment in order to provide adequate patient support. Management requires a multidisciplinary approach to treatment and as part of this GDPs are integral in prevention, early recognition and maintenance of oral health following diagnosis. This article aims to refresh the reader's knowledge regarding MRONJ and ORN and support the GDP in managing this patient group.

Risk factors associated with onset of medication-related osteonecrosis of the jaw in patients treated with denosumab

Objectives

While risk factors of bisphosphonate (BP) associated osteonecrosis of the jaw have been properly analyzed, studies focusing on risk factors associated with denosumab (DNO) are sparse. The purpose of this study was to identify risk factors influencing the onset of medication-related osteonecrosis of the jaw (MRONJ) in patients receiving antiresorptive treatment (ART) with DNO by comparing patients suffering from MRONJ and patients without MRONJ. Multiple variables were evaluated including the impact of a previous BP intake.

Materials and methods

A retrospective single-center cohort study with patients receiving DNO was conducted. One-hundred twenty-eight patients were included and divided into three groups: I (control, n = 40) receiving DNO with absence of MRONJ; group II (Test 1, n = 46), receiving DNO with presence of MRONJ; and group III (Test 2, n = 42) sequentially receiving BP and DNO with presence of MRONJ. Patients’ medical history, focusing on the identification of MRONJ risk factors, was collected and evaluated. Parameters were sex, age, smoking habit, alcohol consumption, underlying disease (cancer type, osteoporosis), internal diseases, additional chemo/hormonal therapy, oral inflammation, and trauma.

Results

The following risk factors were identified to increase MRONJ onset significantly in patients treated with DNO: chemo/hormonal therapy (p = 0.02), DNO dosage (p < 0.01), breast cancer (p = 0.03), intake of corticosteroids (p = 0.04), hypertension (p = 0.02), diabetes mellitus (p = 0.04), periodontal disease (p = 0.03), apical ostitis (p = 0.02), and denture use (p = 0.02). A medication switch did not affect MRONJ development (p = 0.86).

Conclusions

Malignant diseases, additional chemotherapy, DNO dosage, and oral inflammations as well as diabetes mellitus and hypertension influence MRONJ onset in patients treated with DNO significantly.

Clinical relevance

Patients receiving ART with DNO featuring aforementioned risk factors have a higher risk of MRONJ onset. These patients need a sound and regular prophylaxis in order to prevent the onset of MRONJ under DNO treatment.

Denosumab-related osteonecrosis of the jaw after tooth extraction and the effects of a short drug holiday in cancer patients: a multicenter retrospective study

Pre-existing inflammation, corticosteroid therapy, periapical periodontitis, longer duration of denosumab therapy, and female sex were significantly associated with an increased risk of denosumab-related osteonecrosis of the jaw after tooth extraction in patients with cancer on oncologic doses of denosumab. A short drug holiday did not protect against this complication.

INTRODUCTION

This study retrospectively investigated the relationship between various risk factors, including brief discontinuation of denosumab, and development of denosumab-related osteonecrosis of the jaw (DRONJ) after tooth extraction in patients with cancer who were receiving oncologic doses of this agent.

METHODS

Data were collected on demographic characteristics, duration of denosumab therapy, whether or not denosumab was discontinued before tooth extraction (drug holiday), duration of discontinuation, presence of pre-existing inflammation, and whether or not additional surgical procedures were performed. Risk factors for DRONJ after tooth extraction were evaluated by univariate and multivariate analyses.

RESULTS

A total of 136 dental extractions were performed in 72 patients (31 men, 41 women) with cancer who were receiving oncologic doses of denosumab. Post-extraction DRONJ was diagnosed in 39 teeth (28.7%) in 25 patients. Tooth extraction was significantly associated with development of DRONJ only in patients with pre-existing inflammation (odds ratio [OR] 243.77), those on corticosteroid therapy (OR 73.50), those with periapical periodontitis (OR 14.13), those who had been taking oncologic doses of denosumab for a longer period (OR 4.69), and in women (OR 1.04). There was no significant difference in the occurrence of DRONJ between patients who had a drug holiday before tooth extraction and those who did not.

CONCLUSIONS

These findings suggest that inflamed teeth should be extracted immediately in patients with cancer who are receiving oncologic doses of denosumab. Drug holidays have no significant impact on the risk of DRONJ.

Evaluation of Preventive Treatment Protocols for Patients under Antiresorptive Therapy Undergoing Tooth Extraction at a Swiss University Clinic

Antiresorptive agent-related osteonecrosis of the jaw (ARONJ) is a dreaded complication in patients with compromised bone metabolism. The purpose of the present study was to examine the occurrence of ARONJ and its related factors among patients with a history of antiresorptive therapy undergoing tooth extraction using preventive protocols at a Swiss university clinic. Data were retrospectively pooled from health records of patients having received a surgical tooth extraction between January 2015 and April 2020 in the Clinic of Cranio-Maxillofacial and Oral surgery, University of Zurich. A total of 970 patients received an extraction with flap elevation or wound closure during this period. A total of 104 patients could be included in the study. Furthermore, variables including age, gender, smoking, risk profile, choice, indication and duration of antiresorptive therapy, number of extractions, extraction site, surgical technique, choice and duration of antibiotics as well as the presence of postoperative inflammatory complications were assessed. Overall, 4 patients developed ARONJ (incidence of 3.8%) after tooth extraction at the same location, without previous signs of osteonecrosis. Preventive methods included predominantly primary wound closure using a full thickness mucoperiosteal flap and prolonged perioperative antibiotic prophylaxis. In accordance with current literature, the applied protocol showed a reliable outcome in preventing ARONJ when a tooth extraction is required.

Lack of evidence in reducing risk of MRONJ after teeth extractions with systemic antibiotics

A systematic review was carried out to identify if periprocedural administration of systemic antibiotics could decrease risk of medication-related osteonecrosis of the jaws (MRONJ) in patients under antiresorptive and/or biologic agents for teeth extraction. PubMed/MEDLINE and Scopus were systematically searched for case-series with more than 10 patients, retrospective/prospective studies, and trials concerning this issue. Manual searching of references from previous reviews was also carried out. Of 1,512 results, 17 studies were included, focusing on antibiotics for extraction in patients under intravenous bisphosphonates (8 studies), oral bisphosphonates (2 studies), oral and intravenous bisphosphonates (6 studies), and denosumab (1 study), of which 12 performed dental extraction with surgical flap. With no trials found, "quality in prognosis studies" (QUIPS) tool was used to evaluate risk of bias. First-line treatment was 2-3 grams of oral amoxicillin in 76.4% of studies; 300-600 mg of clindamycin was the alternative treatment in 23.5% of studies. Treatment ranged from 3 to 20 days, consisting of 6-7 days in 47% of studies. No microbiologic insight was provided. A significantly higher risk of MRONJ for patients unexposed to antibiotics was provided in one retrospective study. QUIPS tool revealed moderate-high risk of bias. With empirical data from bias-carrying, heterogeneous observational studies, the validity of antibiotics is yet to be established.

What is the Risk of Developing Medication-Related Osteonecrosis in Patients With Extraction Sockets Left to Heal by Secondary Intention? A Retrospective Case Series Study

PURPOSE

Tooth and root extractions represent trigger factors for medication-related osteonecrosis of the jaw (MRONJ). The best healing modality for postextraction sockets is still debated. The aim of the study was to estimate the incidence of MRONJ after extractions whose sockets were left to heal by secondary intention.

METHODS

A retrospective case series study was performed at the Department of Odontostomatological and Maxillofacial Sciences, Sapienza University of Rome. Only patients who underwent nonsurgical extractions, healed by secondary intention, were included in the study. The following parameters were considered: age, sex, pathologies for which bisphosphonates or other drugs related to MRONJ were prescribed, any local or systemic risk factors, type of drug used, route of administration, number of extractions performed, and number of sessions required to complete the extraction program. The main outcome variable was the occurrence of MRONJ. Statistical analysis was performed with SPSS statistical software.

RESULTS

Two hundred twenty-one patients were treated from 2007 to 2020 with 639 tooth/root extractions. All patients were treated under antibiotic prophylaxis and with anesthesia without vasoconstrictors. No cases of MRONJ occurred. The mean age of patients was 68.02 ± 11.17. Most of the study sample was represented by women (201 = 90.95%) undergoing treatment for osteometabolic pathologies, most frequently postmenopausal osteoporosis. Alendronate was the most frequently prescribed drug, taken mainly orally. Most patients had local and/or systemic risk factors. Each patient had from 1 to 17 tooth/root extractions (mean = 2.87 ± 2.59) during 1 to 4 sessions (mean = 1.41 ± 0.64). Extractions mainly involved single-rooted teeth/roots, equally distributed between the maxilla and mandible.

CONCLUSIONS

Secondary intention healing after nonsurgical tooth extraction does not seem to predispose to MRONJ. It can be advisable to perform extractions under antibiotic prophylaxis using anesthetics without vasoconstrictors and chlorhexidine mouth rinses in the 7 following days.

Comparing the Surgical Response of Bisphosphonate-Related Versus Denosumab-Related Osteonecrosis of the Jaws

PURPOSE

The pathophysiology and treatment of medication-related osteonecrosis of the jaws (MRONJ) remain unclear after nearly two decades of recorded observation and discussion. The purpose of this study was to assess outcomes of surgical resection of MRONJ in patients exposed to denosumab.

MATERIALS AND METHODS

A literature review was performed in conjunction with experts at the University of Illinois at Chicago Library. The primary outcome of interest was surgical success defined by maintenance of complete mucosal closure without bone exposure and infection after surgical resection. Secondary interests included demographics, MRONJ stage, location of the focus of osteonecrosis, and the primary underlying disease necessitating antiresorptive treatment. Statistical analysis was performed by χ², analysis of variance, or t test (P < .05 and b = 0.2 or a power of 0.8).

RESULTS

A total of 70 articles were identified and 14 met inclusion criteria. Twenty patients were included (13 women; 7 men); age 61.8 years ± 12.9 (range 19 to 77); and MRONJ stage I (40.0%), II (35.0%), and III (25.0%). Most cases occurred in the mandible (65.0%), followed by the maxilla (30.0%). The success rate of surgical intervention for MRONJ secondary to denosumab was in 16 of 20 (80.0%) patients. Stage I MRONJ lesions achieved mucosal closure in 100% of patients, stage II in 71.4%, and stage III in 60.0%. The surgical success rate was 83.3% in the maxilla and 76.9% in the mandible.

CONCLUSIONS

The surgical success rate for MRONJ secondary to denosumab was 80.0%, similar to that reported in bisphosphonates of 85 to 95%; however, more evidence must be reported and analyzed.

Update and review of the gerodontology prospective for 2020's: Linking the interactions of oral (hypo)-functions to health vs. systemic diseases

New lines of evidence suggest that the oral-systemic medical links and oral hypo-function are progressively transcending beyond the traditional clinical signs and symptoms of oral diseases. Research into the dysbiotic microbiome, host immune/inflammatory regulations and patho-physiologic changes and subsequent adaptations through the oral-systemic measures under ageism points to pathways leading to mastication deficiency, dysphagia, signature brain activities for (neuro)-cognition circuitries, dementia and certain cancers of the digestive system as well. Therefore, the coming era of oral health-linked systemic disorders will likely reshape the future of diagnostics in oral geriatrics, treatment modalities and professional therapies in clinical disciplines. In parallel to these highlights, a recent international symposium was jointly held by the International Association of Gerontology and Geriatrics (IAGG), Japanese Society of Gerodontology (JSG), the representative of USA and Taiwan Academy of Geriatric Dentistry (TAGD) on Oct 25th, 2019. Herein, specific notes are briefly addressed and updated for a summative prospective from this symposium and the recent literature.

The role of M1 and M2 macrophage polarization in progression of medication-related osteonecrosis of the jaw

OBJECTIVES

The aim of this study was to investigate the relationship between M1 and M2 macrophage polarization and clinical stage in patients with medication-related osteonecrosis of the jaw (MRONJ) who underwent treatment with bisphosphonates or denosumab.

MATERIALS AND METHODS

M1 and M2 macrophage density and expression of interleukin (IL)-6 and IL-10 were assessed on biopsies of mucosal tissues surrounding necrotic bone in 30 MRONJ patients with stages 1-3 and controls. For identification of M1 and M2 macrophages, double CD68/iNOS and CD68/CD206 immunofluorescence staining was conducted, respectively. Computer-assisted immunofluorescence quantification of markers was performed.

RESULTS

Early stage 1 MRONJ patients showed a switch toward the M2 phenotype, as indicated by the higher density of M2 macrophages, the decreased M1/M2 ratio, and the upregulation of IL-10. MRONJ patients with advanced stages 2 and 3 showed a shift toward M1-polarized macrophages, as suggested by the higher density of M1 macrophages, the increased M1/M2 ratio, and the overexpression of IL-6. The macrophage density of both M1 and M2 subsets was significantly enhanced in patients receiving bisphosphonates compared with those receiving denosumab.

CONCLUSIONS

The M1-M2 macrophage polarization status in mucosal tissues bordering necrotic bone correlates with clinical stage of MRONJ. Patients with early-stage MRONJ show a switch toward M2-polarized macrophages, while MRONJ patients with advanced stage demonstrate a shift toward the M1 phenotype.

CLINICAL RELEVANCE

Therapeutic molecules targeting the inflammatory microenvironment via the regulation of either M1 or M2 macrophage polarization may represent a novel strategy for treatment of MRONJ.

Wound closure and alveoplasty after preventive tooth extractions in patients with antiresorptive intake-A randomized pilot trial

OBJECTIVES

To compare success rates between the sub-periosteal prepared (SPP) muco-periosteal flap and the epi-periosteal prepared (EPP) mucosa flap and the feasibility of alveoplasty after surgical tooth extractions in patients undergoing/after antiresorptive treatment.

SUBJECTS

Patients with an indication for preventive tooth extraction undergoing/after antiresorptive treatment were enrolled over a 24-month period in a parallel-group randomized clinical pilot trial and randomly assigned for primary wound closure to either the SPP or the EPP group. The primary outcome was treatment failure 8 weeks after surgery. To assess the feasibility of alveoplasty, necrotic bone changes at the time point of tooth extraction were evaluated.

RESULTS

One hundred and sixty patients were randomized to the SSP (n = 82) or the EPP (n = 78) group. One hundred and fifty-seven patients met the primary endpoint 8 weeks after surgery with five treatment failures for the SPP group (6.3%) and 18 (23.4%) for the EPP group (p = .004). A significant relationship (p < .0001) was observed between symptomatic teeth and non-vital bone found in 54.8% of all biopsies.

CONCLUSIONS

The strong superiority of the muco-periosteal flap as primary wound closure revealed the feasibility and effectiveness of the study. The large number of necrotic biopsies emphasizes the importance of alveoplasty as a preventive measure.

Discontinuation of Denosumab as a Potential Cause of Generalized External Cervical Root Resorption: A Case Report

Generalized occurrence of external root resorption in an adult patient is a rare finding. This case report describes external cervical root resorption extensively affecting the dentition that may be associated with the use and subsequent cessation of denosumab for the treatment of osteoporosis.

Adipose-derived stem cells prevent the onset of bisphosphonate-related osteonecrosis of the jaw through transforming growth factor β-1-mediated gingival wound healing

Background

Due to its complex pathogenesis and low clinical cure rate, bisphosphonate-related osteonecrosis of the jaw (BRONJ) poses a substantial challenge for oral and maxillofacial surgeons. Therefore, the treatment of BRONJ should focus on prevention. In clinical studies, primary wound closure can significantly reduce the incidence of BRONJ. Whether local stem cell transplantation can promote primary gingival healing in patients with a medication history and prevent BRONJ has not been reported.

Methods

In this study, animals were divided into a healthy group (non-drug treatment), a BP group, a hydroxyapatite (HA) group, and an adipose-derived stem cell (ADSC) group. All groups except the healthy group were treated with BPs and immunosuppressive drugs once per week for 8 weeks, simulating clinical use for the treatment of cancer patients with bone metastasis, to induce BRONJ-like animals. After the sixth drug treatment, the bilateral premolars were extracted in all groups. In contrast to the healthy and BP groups, the extraction sockets in the HA and ADSC groups were filled with HA or HA + ADSCs simultaneously post extraction to observe the preventive effect of ADSCs on the occurrence of BRONJ. At 2 and 8 weeks post extraction, animals from all groups were sacrificed.

Results

At 8 weeks post transplantation, ADSCs prevented the occurrence of BRONJ, mainly through accelerating healing of the gingival epithelium at 2 weeks post extraction. We also found that ADSCs could upregulate the expression of transforming growth factor β1 (TGF-β1) and fibronectin in tissue from animals with a medication history by accelerating gingival healing of the extraction socket. A rescue assay further demonstrated that TGF-β1 and fibronectin expression decreased in TGF-β1-deficient ADSC-treated animals, which partially abolished the preventive effect of ADSCs on the onset of BRONJ.

Conclusion

ADSCs prevent the onset of BRONJ, mainly by upregulating the expression of TGF-β1 and fibronectin to promote primary gingival healing, ultimately leading to bone regeneration in the tooth extraction socket. Our new findings provide a novel stem cell treatment for the prevention of BRONJ.

Electronic supplementary material

The online version of this article (10.1186/s13287-019-1277-y) contains supplementary material, which is available to authorized users.

[Progress on medication-related osteonecrosis of the jaw]

Medication-related osteonecrosis of the jaw (MRONJ) is a severe complication of bisphosphonates (BPs) or other targeted agent therapies. MRONJ appears as exposed bone, pus, and swelling in the oral and maxillofacial regions. However, neither surgery nor conservative therapy can eliminate symptoms thoroughly. In addition to BPs, several antiresorptive and antiangiogenic agents, such as denosumab and bevacizumab, as well as targeted agents, such as sunitinib and temsirolimus, can cause osteonecrosis of  the  jaw according to the literature. This review aims to summarize the research progress on these new drugs.

Epidermal Growth Factor Reverses the Inhibitory Effects of the Bisphosphonate, Zoledronic Acid, on Human Oral Keratinocytes and Human Vascular Endothelial Cells In Vitro via the Epidermal Growth Factor Receptor (EGFR)/Akt/Phosphoinositide 3-Kinase (PI3K) Signaling Pathway

Background

Medication-related osteonecrosis of the jaw (MRONJ) is due to the direct effects of drug toxicity and the effects on angiogenesis. The aims of this study were to evaluate the effects of treatment with the bisphosphonate, zoledronic acid, on human oral keratinocytes (HOKs) and human umbilical vein endothelial cells (HUVECs) in vitro, and whether epidermal growth factor (EGF) could alter these effects.

Material/Methods

HOKs and HUVECs were incubated with zoledronic acid or EGF. Cell viability was assessed by the cell counting kit-8 (CCK-8), cell apoptosis was studied using Annexin-V conjugated to fluorescein isothiocyanate (FITC). Angiogenesis was studied by observing HUVEC tube formation and cell migrations using a transwell assay. A scratch wound assay investigated cell migration of HOKs. Western blot measured expression levels of phosphorylated epidermal growth factor receptor (EGFR), Akt, phosphoinositide 3-kinase (PI3K), the mechanistic target of rapamycin (mTOR), and endothelial nitric oxide synthase (eNOS).

Results

Zoledronic acid treatment (5 μmol/L) significantly inhibited cell viability and cell migration of HOKs and HUVECs and angiogenesis of HUVECS (P<0.05); EGF partially reversed these effects (P<0.05). Zoledronic acid treatment of HOKs and HUVECs had no significant effects on apoptosis (P>0.05), but significantly reduced expression levels of p-EGFR, p-Akt, p-PI3K, p-mTOR), and p-eNOS (P<0.05); EGF partially reversed these effects and increased the expression levels (P<0.05).

Conclusions

EGF partially reversed the effects of the bisphosphonate, zoledronic acid, on HOKs and HUVECs in vitro via the EGFR/Akt/PI3K signaling pathway. Further studies are required to determine the effects of EGF on MRONJ including bisphosphonate-related osteonecrosis of the jaw.

Antiresorptive agent-related osteonecrosis of the jaw in osteoporosis patients from Asian countries

Bisphosphonate (BP)-associated osteonecrosis of the jaw (ONJ) was first reported in oncology patients in 2003 and subsequently in osteoporosis patients in 2004. Since oral surgical procedures, such as tooth extraction, are also considered one of the major risk factors for ONJ, there is confusion among physicians, dentists, and patients—particularly osteoporosis patients currently taking BPs—regarding the safety of remaining on therapy surrounding these procedures. Many papers about BP-related ONJ (BRONJ) have been published to date. In addition to BRONJ, recent studies have reported an association between ONJ and the antiresorptive therapy denosumab (Dmab; a RANKL-inhibitor). BRONJ and Dmab-related ONJ are together referred to as antiresorptive agent-related ONJ (ARONJ). The pathogenesis of ARONJ still remains unknown. It is forecasted that there will be an increased incidence of patients with osteoporotic fractures and an increased number of prescriptions for antiresorptive agents in Asia in the future. However, prescriptions for antiresorptives for osteoporosis may be restricted in the Asian population as the occurrence of ARONJ may be higher as compared with those in other countries. In this review, we focused on the following topics as it pertains to the Asian osteoporotic population: the oral condition specific for osteoporosis patients; definition, staging, prevalence and incidence of ARONJ; imaging modalities for ARONJ; specific risk factors for ARONJ; prevention strategies for ARONJ, and; cooperation between physicians and dentists in the prevention of ARONJ. Ideally, the Asian Federation of Osteoporosis Societies would cooperate with one another and find more population-specific evidence for the prevention of ARONJ.

Antiresorptive agent-related osteonecrosis of the jaw: Position Paper 2017 of the Japanese Allied Committee on Osteonecrosis of the Jaw

Antiresorptive agent-related osteonecrosis of the jaw (ARONJ) is an intractable, though rare, complication in cancer patients with bone metastases and patients with osteoporosis who are treated with antiresorptive agents, including bisphosphonates and denosumab. Despite the more than 10 years that have passed since the first cases of bisphosphonate-related osteonecrosis of the jaw (BRONJ) were reported, our understanding of the epidemiology and pathophysiology of ARONJ remains limited, and data supported by evidence-based medicine are still sparse. However, the diagnosis and staging of ARONJ, identification of risk factors, and development of preventive and therapeutic approaches have advanced significantly over the past decade. The Position Paper 2017 is an updated version of the Position Paper 2010 of the Japanese Allied Committee on Osteonecrosis of the Jaw, which now comprises six Japanese academic societies. The Position Paper 2017 describes a new diagnostic definition for ARONJ, as proposed by the American Association of Oral and Maxillofacial Surgeons (AAOMS), summarizes our current understanding of the pathophysiology of ARONJ based on a literature search, and suggests methods for physicians and dentists/oral surgeons to manage the disease. In addition, the appropriateness of discontinuing antiresorptive medications (drug holiday) before, during, and after invasive dental treatments is discussed extensively. More importantly, the manuscript also proposes, for the first time, the importance of interactive communication and cooperation between physicians and dentists/oral surgeons for the successful treatment of ARONJ. The Position Paper 2017 is intended to serve as a guide for improving the management of ARONJ patients in Japan.