Management of bisphosphonate-related osteonecrosis of the jaw: a literature review

Raman spectroscopy and U-Net deep neural network in antiresorptive drug-related osteonecrosis of the jaw

OBJECTIVE

Application of an optical method for the identification of antiresorptive drug-related osteonecrosis of the jaw (ARONJ).

METHODS

We introduce shifted-excitation Raman difference spectroscopy followed by U-Net deep neural network refinement to determine bone tissue viability. The obtained results are validated through established histological methods.

RESULTS

Discrimination of osteonecrosis from physiological tissues was evaluated at 119 distinct measurement loci in 40 surgical specimens from 28 patients. Mean Raman spectra were refined from 11,900 raw spectra, and characteristic peaks were assigned to their respective molecular origin. Then, following principal component and linear discriminant analyses, osteonecrotic lesions were distinguished from physiological tissue entities, such as viable bone, with a sensitivity, specificity, and overall accuracy of 100%. Moreover, bone mineral content, quality, maturity, and crystallinity were quantified, revealing an increased mineral-to-matrix ratio and decreased carbonate-to-phosphate ratio in ARONJ lesions compared to physiological bone.

CONCLUSION

The results demonstrate feasibility with high classification accuracy in this collective. The differentiation was determined by the spectral features of the organic and mineral composition of bone. This merely optical, noninvasive technique is a promising candidate to ameliorate both the diagnosis and treatment of ARONJ in the future.

[The recombinant human parathyroid hormone, teriparatide as an alternative remedy for the medication-related osteonecrosis of the jaw]

In developed countries, osteoporosis is one of the most common debilitating conditions in the population over the age of 50. Unfortunately, the pathomechanism of the disease is still not fully understood. Nowadays, the administration of antiresorptive drugs blocking osteoclastic activity is the most commonly used medication to slow down the speed of the bone loss. One of the uncommon side effects of such drugs is the medication-related osteonecrosis of the jaw (MRONJ). Recently, a number of alternative therapeutic approaches has been tested and published, amongst them the recombinant human parathyroid hormone (rhPTH, teriparatide) use, which is turning into a promising treatment modality. According to certain meta-analyses, its pharmacological effect on increasing bone mineral density and controlling pathological vertebral fractures is superior to antiresorptive drugs; however, the so-called "off-label" application of teriparatide remains controversial. As intermittent administration of teriparatide stimulates bone formation, several animal and clinical studies indicated that systemic application of teriparatide shortened fracture healing time and improved quality of the callus and the newly formed bone. Furthermore, recently several clinical studies showed the beneficial effect of the intermittent rhPTH administration in the management of MRONJ. This article reviews the history of the anabolic effect of the low-dose rhPTH discovery, provides evidence-based data from animal and human studies, summarizes its biological mechanisms and the clinical benefits of the anabolic therapy and also their possible role in the management of MRONJ. The majority of the clinical data indicates that, in the case of therapy-resistant osteonecrosis, it may be worthwhile to apply short-term intermittent teriparatide therapy. Notwithstanding, more randomized clinical trials are necessary in order to confirm the efficacy and the safety of the use of teriparatide in the treatment of MRONJ. Orv Hetil. 2023; 164(36): 1406-1415.

Controlling sustained statins release in multi-layered composite scaffolds for healing of osteoporotic bone defects

The risk of fragility fracture sharply increases due to the decreased bone mineral density and toughness in patients with osteoporosis (OP). The local use of bone tissue scaffolds with both mechanical stability and drug-delivery functionality is one of the key strategies for the efficient curing of OP. In this work, we reported a layer-by-layer constructing strategy to fabricate 3-D composite bone tissue scaffolds (eSTPS) by assembling β-tri‑calcium phosphate (β-TCP)/polycaprolactone (PCL) microchips and lovastatin-loaded nanofiber membranes (eLOV/PCL). The eSTPS scaffolds show a strong and suited compressive strength as well as long-term delivery of lovastatin. The in vitro tests indicate well biocompatibility and alkaline phosphatase activity of the scaffolds. The eSTPS scaffolds were implanted into the femur of OP modeled rabbits. After 12 weeks curing, the bone parameters are significantly improved, meanwhile ingrowth of new bone and vascular-like tissue were observed. These results suggest the eSTPS scaffolds to be a promising candidate for the local treatment of OP.

Titanium implant alters the effect of zoledronic acid on the behaviour of endothelial cells

OBJECTIVES

To evaluate the effect of zoledronic acid (ZA) on human umbilical vein endothelial cells (HUVECs) attached to different surfaces.

MATERIALS AND METHODS

A total of three groups were evaluated in this study: sandblasting and acid etching (SLA) + HUVECs; mechanically polished (MP) + HUVECs; and plastic cell culture plates + HUVECs. Scanning electron microscopy, energy-dispersive X-ray spectroscopy, surface roughness and water contact angle were tested for titanium surface characterisation. ZA was added at different concentrations (0, 1, 10, 50 and 100 μM). Cell adhesion, proliferation, viability, apoptosis and gene expression were evaluated.

RESULTS

Mechanically polished and SLA surfaces showed negative effects on cell adhesion and proliferation and promoted cell apoptosis with 100 μM ZA (p < .05). The highest expression of intercellular adhesion molecule-1 (ICAM-1) and angiopoietin-1 was found on SLA surfaces (p < .01). The lowest expression of platelet-endothelial cell adhesion molecule-1 and ICAM-1 was found on MP surfaces (p < .05). A significant decrease in von Willebrand factor was detected on MP and SLA surfaces (p < .001).

CONCLUSIONS

Zoledronic acid has an anti-angiogenic effect on HUVECs attached to titanium implants, while the SLA surface might stimulate HUVECs to express angiogenic and adhesive factor genes despite ZA treatment.

Emerging therapies with potential risks of medicine-related osteonecrosis of the jaw: a review of the literature

In the past, osteonecrosis of the jaw (ONJ) was generally reported with bisphosphonate drugs; hence, the term BRONJ (bisphosphonate-related osteonecrosis of the jaw) was initially proposed. This was followed by the term ARONJ (antiresorptive osteonecrosis of the jaw). More recently, other novel medications such as vascular endothelial growth factor (VEGF) inhibitors, tyrosine kinase inhibitors and humanised antibodies that affect osteoclastic action have been reported to initiate ONJ in several cases. For this reason, in 2014, the American Association of Oral and Maxillofacial Surgeons (AAOMS) changed the term to MRONJ - medication-related osteonecrosis of the jaw. The review primarily focuses on ONJ associated with emerging therapies for the management of bone disorders. This article sheds some light on the risk factors that predispose dental patients to the development of osteonecrosis, the mechanisms of drug therapies associated with MRONJ, and potential treatment and management regimes for MRONJ patients. The current review noted that the incidence and associated risk of MRONJ is significant with the new therapeutic agents discussed. Therefore, for optimised patient care, pharmacovigilance with the new medications is essential for dental professionals.

Replacing one evil with another: Is the fibula really a dispensable spare part available for transfer in patients with medication-related osteonecrosis of the jaws?

Because of the long-term and consecutive use of different causative agents, clinicians are increasingly encountering patients needing restoration of the stomatognathic system after surgical resection of highly advanced necroses of the jaw. For plastic restoration in these cases, microvascular reconstruction seems to represent the most viable option. According to the limited data available, the risks of this operation are considered comparable with those faced by other patient cohorts. We report here the case of a patient who suffered 2 successive pathologic fractures of the tibia after microsurgical reconstruction of the mandible with a free fibula flap. This exemplifies a general problem, especially because the patient also suffered from a treatment-refractory infection of the transplanted bone. Although the present literature indicates otherwise, fibula transplants might not be the gold standard in these cases. Therefore, alternatives to transplants from the weight-bearing parts of the body need to be considered until more data are available.

The effects of different doses of teriparatide on bisphosphonate-related osteonecrosis of the jaw in mice

OBJECTIVES

This study aimed to investigate the therapeutic effect of different doses of teriparatide (TPTD) on bisphosphonate-related osteonecrosis of the jaw (BRONJ).

MATERIALS AND METHODS

To establish the BRONJ model, 20 mice were randomly divided into two groups: a group that received tail vein administration of zoledronic acid with dexamethasone (ZA-125 µg/kg, DEX 5 mg/kg) and a group that received saline weekly. The mice subsequently underwent bilateral maxillary first molar extraction. After 8 weeks of modelling administration, the maxilla samples were examined by micro-computed tomography and histological staining (haematoxylin and eosin, Masson's trichrome and tartrate-resistant acid phosphatase) and the cytokine level was measured (enzyme-linked immunosorbent assay and Western blot). To determine the role of TPTD in BRONJ, the same protocol as previously described was applied in 100 mice (80 received ZA + DEX, and 20 received saline). After 8 weeks of modelling administration, 80 ZA + DEX mice were randomly divided into four groups: three groups with subcutaneous administration of TPTD (i.e. T1-3, T2-10 and T3-30 µg kg^-1  day^-1 ) and one group with saline daily for the next 8 weeks. The other 20 saline mice continued to receive saline daily.

RESULTS

In Part 1, the level of receptor activator of nuclear factor-kappa Β ligand and the numbers of osteoclasts differed between the model and control groups. In Part 2, we found that TPTD had a positive effect on BRONJ in a mouse model based on clinical and histomorphological observations. Among the three treatment groups, the T1 and T2 groups significantly differed from the model group, whereas the T3 group showed no statistical differences.

CONCLUSION

Subcutaneous administration of TPTD has a beneficial effect on BRONJ in mice. Nevertheless, further studies are needed to determine whether the therapeutic effect on BRONJ is dose-dependent.

Osthole improves therapy for osteoporosis through increasing autophagy of mesenchymal stem cells

Osteoporosis is a common skeletal disorder resulting in elevated fracture risk. Improvement of osteogenic differentiation is thought to be the top priority in osteoporosis treatment projects. Significant characteristics of bone marrow mesenchymal stem cells (BMMSCs), especially attractive ability to differentiate into osteoblasts, have made them alternatives for osteoporosis treatment. However, therapeutic effect with BMMSCs remains to be improved. Here, osthole, a bioactive simple coumarin derivative extracted from many medicinal plants, was introduced to pre-stimulate BMMSCs and then applied in osteoporosis therapy. The results showed that osthole-treated-BMMSCs (OBMMSCs) brought a better outcome than BMMSCs alone in estrogen deficiency-induced osteoporosis model. And elevated autophagy level was suggested to be the underlying mechanism of the ability of osthole to promote osteoblast differentiation, which is indicated by the upregulation of protein and mRNA expression level of autophagy-associated genes, Beclin1 and LC3. We concluded from these experiments that OBMMSCs are more effective than BMMSCs in osteoporosis treatment maybe through upregulation level of autophagy level induced by osthole.

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.

Medication-related osteonecrosis of the jaw associated with implant and regenerative treatments: Systematic review

BACKGROUND

The aim of this study was to determine if the treatment with bisphosphonates other anti-resorptive and antiangiogenic agents influences the success of regenerative and / or implant treatments.

MATERIAL AND METHODS

We reviewed the literature from the last 5 years in the PubMed database, using the following words: "Sinus Floor Augmentation"[Mesh] OR "Dental Implants"[Mesh]) OR "Guided Tissue Regeneration"[Mesh]) AND "Osteonecrosis"[Mesh]. The articles were selected following the inclusion and exclusion criteria and were evaluated using the 22 items of the STROBE declaration. The following PICO clinical question was applied: Does the treatment with agents associated with drug osteonecrosis influence the success of regenerative and implant treatments?

RESULTS

The initial search resulted in a total of 27 articles. After eliminating those that did not refer to the topic, were duplicated or did not meet the inclusion / exclusion criteria, a full reading of the articles was made evaluating their methodological quality, obtaining six studies with high methodological quality and two with moderate.

CONCLUSIONS

The literature regarding this topic is scarce, randomized clinical trials would be necessary to establish protocols relative to implant treatment in patients on antiresorptive treatments. The risk of developing an osteonecrosis associated with the regeneration / implant placement in patients with benign bone diseases is scarce, but it exists and it should not be underestimated. Especially, in the posterior areas of the jaw, if the duration of treatment with BP is greater than 3 years, and if the patient is under therapy with systemic corticosteroids.

Density functional theory studies on a non-covalent interaction system: hydrogen-bonded dimers of zoledronate

A computational study was carried out to characterize the hydrogen-bonded dimers of Zoledronate (ZOL), which is used widely in treating skeletal diseases. The stable conformations, hydrogen bonding interactions, IR spectra, thermodynamic properties, and electronic characteristics of nine possible ZOL dimers were studied using density functional theory (DFT) at the B3LYP/6-311++G** level. The stability of dimers was determined according to the analyses of total electronic energies and hydrogen bonding interactions. The results showed that both the number and intensity of hydrogen bonds played an important role in determining the stability order of dimers, and the hydrogen bonding interactions in dimers resulted in a red shift of hydroxyl vibration with a corresponding increase in intensity. The calculated thermodynamic properties illustrated that the dimerization process can take place spontaneously at room temperature. Natural bond orbital and atoms in molecules analyses revealed that the nature of hydrogen bonding interactions was attributed to the interactions from lone pair orbital n(A) to the antibonding orbital σ*(D-H), and the interactions were closed-shell interactions in hydrogen-bonded dimers of ZOL. Graphical abstract Changes in Gibbs free energy and infrared spectra of ZL in the dimerization process.

Combined Approach to Treat Medication-Related Osteonecrosis of the Jaws

Introduction: The proper therapeutic plan for medication-related osteonecrosis of the Jaw (MRONJ) is still lacking long-term data up to today. They were several high-technological appliances proposed for the different intervention steps, in addition to tissue repair promoters. The reason for proposing an integrated technique is justified, beyond better compliance of the patients associated to the pain and inflammation reduction and bleeding control, there is also achieving better hard and soft tissues healing. Methods: Patients diagnosed with bisphosphonates-related osteonecrosis of the jaws (BRONJ) at the Odontostomatology and Maxillo-Facial Surgery Unit of the Hospital of Piacenza undergone surgical intervention. The intervention was performed by using different devices: Piezosurgery for removing the necrotic bone tissue and for obtaining the bone specimen essential for histological analysis; Er:YAG laser (2940 nm) to vaporize necrotic hard tissue until reaching the bleeding bone; platelet-rich plasma (PRP) to stimulate hard and soft tissue healing; and finally diode laser (808 nm) to perform a biostimulation of the surgical site. Results: All treated patients demonstrated a good postoperative comfort even without using painkillers, no bleeding, and a fast healing process. Most of the patients (92.85%) reached complete healing with a minimum follow up at 6 months. Histological exams demonstrated a good quality without artifacts. Conclusion: Sequential utilization of different high-technologies devices during all the steps of MRONJ treatment allows to perform a faster and less invasive surgery with a more comfortable postoperative healing process and it may represent a new and original approach for treating this severe adverse event.

Circulating microRNA Panel as a Novel Biomarker to Diagnose Bisphosphonate-Related Osteonecrosis of the Jaw

There is no defined biomarker for BRONJ diagnosis with satisfactory performance in clinic. In this study, we established the BRONJ model and selected 7 microRNAs as candidate for BRONJ diagnosis from microRNA microarray reported by other research. Dysregulated microRNAs during BRONJ were detected and validated in two independent animal experiments using serum samples. In the first part, serum miR-21, miR-23a and miR-145 were significantly altered in between BRONJ and control group. And an Indice was constructed as -0.032+(0.154×miR-21)+(0.145×miR-23a)+(-0.700×miR-145) using logistic regression model to improve diagnostic performance. The performance of Indice to differentiate BRONJ subjects from control group was analyzed as AUC of 0.82 (95% CI, 0.72-0.92) or 0.85 (95% CI, 0.73-0.97) in the first or second part. Moreover, the predictive performance of Indice to discriminate BRONJ-1w and BRONJ-4w from control group was displayed as AUC of 0.65 (95% CI, 0.47-0.84) or 0.75 (95% CI, 0.60-0.91), which was better than individual circulating microRNAs. In addition, the expressions of candidate microRNAs were validated in human samples. Consequently, we investigated a combined Indice constructed with circulating microRNAs for BRONJ diagnosis and prediction.

Interventions for managing medication-related osteonecrosis of the jaw

BACKGROUND

Medication-related osteonecrosis of the jaw (MRONJ) is a severe adverse reaction experienced by some individuals to certain medicines commonly used in the treatment of cancer and osteoporosis (e.g. bisphosphonates, denosumab and antiangiogenic agents) and involves the progressive destruction of bone in the mandible or maxilla. Depending on the drug, its dosage, and the duration of exposure, the occurrence of this adverse drug reaction may be rare (e.g. following the oral administration of bisphosphonate or denosumab treatments for osteoporosis, or antiangiogenic agent-targeted cancer treatment) or common (e.g. following intravenous bisphosphonate for cancer treatment). MRONJ is associated with significant morbidity, adversely affects quality of life (QoL), and is challenging to treat.

OBJECTIVES

To assess the effects of interventions versus no treatment, placebo, or an active control for the prophylaxis of MRONJ in people exposed to antiresorptive or antiangiogenic drugs.To assess the effects of non-surgical or surgical interventions (either singly or in combination) versus no treatment, placebo, or an active control for the treatment of people with manifest MRONJ.

SEARCH METHODS

Cochrane Oral Health's Information Specialist searched the following databases: Cochrane Oral Health's Trials Register (to 23 November 2016), the Cochrane Central Register of Controlled Trials (CENTRAL) (the Cochrane Library, 2016, Issue 10), MEDLINE Ovid (1946 to 23 November 2016), and Embase Ovid (23 May 2016 to 23 November 2016). The US National Institutes of Health Trials Registry (ClinicalTrials.gov) and the World Health Organization International Clinical Trials Registry Platform were searched for ongoing trials. No restrictions were placed on language or publication status when searching the electronic databases; however, the search of Embase was restricted to the last six months due to the Cochrane Embase Project to identify all clinical trials and add them to CENTRAL.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) comparing one modality of intervention with another for the prevention or treatment of MRONJ. For 'prophylaxis of MRONJ', the primary outcome of interest was the incidence of MRONJ; secondary outcomes were QoL, time-to-event, and rate of complications and side effects of the intervention. For 'treatment of established MRONJ', the primary outcome of interest was healing of MRONJ; secondary outcomes were QoL, recurrence, and rate of complications and side effects of the intervention.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened the search results, extracted the data, and assessed the risk of bias in the included studies. For dichotomous outcomes, we reported the risk ratio (RR) (or rate ratio) and 95% confidence intervals (CI).

MAIN RESULTS

We included five RCTs (1218 participants) in the review. Three trials focused on the prophylaxis of MRONJ. Two trials investigated options for the treatment of established MRONJ. The RCTs included only participants treated with bisphosphonates and, thus, did not cover the entire spectrum of medications associated with MRONJ. Prophylaxis of MRONJOne trial compared standard care with regular dental examinations in three-month intervals and preventive treatments (including antibiotics before dental extractions and the use of techniques for wound closure that avoid exposure and contamination of bone) in men with metastatic prostate cancer treated with zoledronic acid. The intervention seemed to lower the risk of MRONJ: RR 0.10; 95% CI 0.02 to 0.39 (253 participants; low-quality evidence). Secondary outcomes were not evaluated.As dentoalveolar surgery is considered a common predisposing event for developing MRONJ, one trial investigated the effect of plasma rich in growth factors (PRGF) for preventing MRONJ in people with cancer undergoing dental extractions. There was insufficient evidence to support or refute a benefit of PRGF on MRONJ incidence when compared with standard treatment (RR 0.08, 95% CI 0.00 to 1.51; 176 participants; very low-quality evidence). Secondary outcomes were not reported. In another trial comparing wound closure by primary intention with wound closure by secondary intention after dental extractions in people treated with oral bisphosphonates (700 participants), no cases of intraoperative complications or postoperative MRONJ were observed. QoL was not investigated. Treatment of MRONJOne trial analysed hyperbaric oxygen (HBO) treatment used in addition to standard care (antiseptic rinses, antibiotics, and surgery) compared with standard care alone. HBO in addition to standard care did not significantly improve healing from MRONJ compared with standard care alone (at last follow-up: RR 1.56; 95% CI 0.77 to 3.18; 46 participants included in the analysis; very low-quality evidence). QoL data were presented qualitatively as intragroup comparisons; hence, an effect estimate of treatment on QoL was not possible. Other secondary outcomes were not reported.The other RCT found no significant difference between autofluorescence- and tetracycline fluorescence-guided sequestrectomy for the surgical treatment of MRONJ at any timepoint (at one-year follow-up: RR 1.05; 95% CI 0.86 to 1.30; 34 participants included in the analysis; very low-quality evidence). Secondary outcomes were not reported.

AUTHORS' CONCLUSIONS

Prophylaxis of MRONJOne open-label RCT provided some evidence that dental examinations in three-month intervals and preventive treatments may be more effective than standard care for reducing the incidence of MRONJ in individuals taking intravenous bisphosphonates for advanced cancer. We assessed the certainty of the evidence to be low.There is insufficient evidence to either claim or refute a benefit of either of the interventions tested for prophylaxis of MRONJ (i.e. PRGF inserted into the postextraction alveolus during dental extractions, and wound closure by primary or secondary intention after dental extractions). Treatment of MRONJAvailable evidence is insufficient to either claim or refute a benefit for hyperbaric oxygen therapy as an adjunct to conventional therapy. There is also insufficient evidence to draw conclusions about autofluorescence-guided versus tetracycline fluorescence-guided bone surgery.

Selective Percutaneous Controlled Radiofrequency Thermocoagulation of the Gasserian Ganglion To Control Facial Pain Due to Medication-Related Osteonecrosis of the Jaw

BACKGROUND

Medication-related osteonecrosis of the jaw (MRONJ) is an important complication in patients treated with antiresorptive agents such as bisphosphonates and the receptor activator of nuclear factor κB ligand inhibitor (denosumab). Treatment of MRONJ is extremely difficult, which makes it a distressing long-term complication.

OBJECTIVES

We report a case of intractable facial pain due to MRONJ that was successfully controlled with selective percutaneous controlled radiofrequency thermocoagulation of the Gasserian ganglion.

SETTING

A 68-year-old woman with breast cancer was diagnosed as having MRONJ. She was very distressed because of jaw pain and infections secondary to MRONJ. Her quality of life (QOL) was severely decreased. Since alleviation of the MRONJ could not be expected within the patient's life expectancy, it was decided to investigate the usefulness of selective percutaneous controlled radiofrequency thermocoagulation of the Gasserian ganglion to control the pain.

RESULTS

After the procedure, the anesthesia was obtained in the distribution of the third branch of the trigeminal nerve, and the pain completely disappeared. Although hypoesthesia was provoked as a complication, it was tolerated by the patient and she was very satisfied. Up to the time of death, there was no recurrence of pain or worsening of the MRONJ.

DISCUSSION

This procedure is a common technique for treating trigeminal neuralgia. Its effect is immediate and long lasting, although it provokes hypoesthesia in treated division, and it is also suited for cancer patients in terminal stage. This case suggests that the procedure was useful for improving the patient's QOL.

Presenting a Method to Improve Bone Quality Through Stimulation of Osteoporotic Mesenchymal Stem Cells by Low-Level Laser Therapy

OBJECTIVE

This review aims to present a method to improve bone quality through stimulation of osteoporotic mesenchymal stem cells (MSCs) by low-level laser therapy (LLLT).

BACKGROUND

Osteoporosis (OP) is characterized by decreased bone mass and bone strength, which results in an increased incidence of bone fractures. These fractures often lead to additional disability and mortality. Osteoporotic MSCs have reduced osteogenic differentiation when cultured in their standard differentiation media. LLLT has a biostimulatory effect on fibroblasts and osteoblasts. MSCs have the ability to generate cells of connective tissue lineages, which includes the bones. Recently, transplantation of in vitro cultured bone marrow (BM) MSCs into sites at risk for development of osteoporotic bone has resulted in improved bone structure.

METHODS

Comprehensive research was performed using PubMed, and biostimulatory effect of LLLT on bony cells and MSCs were studied.

RESULTS

LLLT can stimulate growth, proliferation, and differentiation of SCs in vitro and in vivo. This ability of LLLT is an essential prerequisite for performing experiments related to disease control in humans. Thus, laser-treated osteoporotic autologous BMMSCs may represent a promising therapeutic method to protect the bones in patients with OP and prevent fractures in these patients. Therefore, researchers hypothesize that transplantation of in vitro laser-treated autologous cultured osteoporotic BMMSCs that have the appropriate osteogenic phenotype into sites at risk for development of osteoporotic bone may result in improved bone structure. In this respect, investigators have successfully used LLLT to restore autologous osteoporotic MSCs in vitro. Subsequently, these cells have been differentiated into osteoblast cell lines with the use of laser treatment after which they were transplanted into osteoporotic animal models.

CONCLUSIONS

This technique might improve bone quality and structure. However, additional research must be undertaken to understand the underlying mechanisms of this treatment, validate its effectiveness, and assess the feasibility for clinical application of LLLT to treat MSCs in regeneration of osteoporotic bone.

[Evaluation of healing time of osteochemonecrosis of the jaw after surgery: Single-center retrospective study and review of the literature]

INTRODUCTION

Osteochemonecrosis of the jaw (ONJ) is a chronic ischemic bone exposure. It has an increasing incidence. ONJ is mainly related to bisphosphonate and denosumab therapies in oncologic settings. Healing is considered uncertain ad as occurring slowly. International recommendations suggest to treat ONJ symptomatically in a first attempt. A surgical procedure, potentially aggressive, should be carefully weight up in patients in poor condition and whose life expectancy is often limited. However, surgical treatment seems to allow for a high rate of clinical remission. Postoperative remission periods, when mentioned in the studies, are disparate. The aim of our study was to clarify the remission period of ONJ after surgical management.

METHOD

A retrospective study was conducted on all patients operated for an ONJ at stage 2 and 3 in the Department for Oral and Maxillofacial Surgery - University Hospital of Besançon (France) from January 2006 to September 2015. Healing was defined as complete mucosal closure and asymptomatic site. Stage of the disease, the number and the type of surgery and the time between the last operation and the healing was noticed. These data were compared to an exhaustive review of the literature on PubMed with the following key-words: "osteonecrosis" AND "jaw" AND "surgery" AND "management". Only the articles giving the healing period were included.

RESULTS

Regarding the single-center retrospective study, the files of 23 patients could be included. Fifteen percent of the patients benefited from several procedures under general anesthesia. Twenty percent had a stage 3 ONJ and 80 % had a stage 2 ONJ. Twenty-five interventions were performed on 23 sites in 20 patients. Immediate healing after surgery occurred in 35 % of the patients. At 6 months after surgery, 57 % of the treated areas were healed. Twenty percent of the patients had died. The healing rate did not improve further after 6 months postoperatively. Regarding the review of the literature, 7 articles could be included. The mean postoperative healing period was 60.7 % at 6 months, 71.1 % at 12 months and 69.5 % at 18 months.

DISCUSSION

Our study shows that the postoperative healing rate of ONJ lies between 57 and 66.7 % at 6 months and that this rate was optimized in the order of 10 % to 12months and stable at 18months postoperatively. The ONJ of our series were partially or fully linked to other drugs than bisphosphonates in 70 % of the cases: 50 % were related to denosumab, alone or in combination and 35 % were related to an association with antiangiogenics, bevacizumab mainly.

Extensive Surgical Procedures Result in Better Treatment Outcomes for Bisphosphonate-Related Osteonecrosis of the Jaw in Patients With Osteoporosis

PURPOSE

To identify the risk factors associated with relapse or treatment failure after surgery for bisphosphonate-related osteonecrosis of the jaw (BRONJ) in patients with osteoporosis.

PATIENTS AND METHODS

We performed a retrospective cohort study of BRONJ in patients with osteoporosis who had undergone surgical procedures from 2004 to 2016 at the Department of Oral and Maxillofacial Surgery, Seoul National University Dental Hospital. The predictor variables were a set of heterogeneous variables, including demographic (age, gender), anatomic (maxilla or mandible, or both, affected location), clinical (disease stage, etiology, comorbidities, history of intravenous bisphosphonate intake), time (conservative treatment before surgery, bisphosphonate treatment before the development of BRONJ, discontinuation of the drug before surgery, interval to final follow-up, interval to reoperation in the case of relapse or treatment failure), and perioperative variables (type of anesthesia, type of surgical procedures). The primary outcome variable was relapse after surgery that required reoperation (yes vs no). The descriptive and bivariate statistics were computed to assess the relationships between the study variables and the outcome. To determine the risk factors, we conducted a survival analysis using the Cox model.

RESULTS

The final sample included 325 subjects with a median age of 75 years, and 97% were women. After surgery, 30% of patients did not completely recuperate and underwent repeat surgery. The interval from the first surgery to reoperation ranged from 10 days to 5.6 years. Relapse or treatment failure most often occurred immediately after surgery. The type of surgical procedure and mode of anesthesia were the most important factors in the treatment outcome. A drug holiday did not appear to influence the likelihood of relapse after surgery.

CONCLUSIONS

Treatment of BRONJ in patients with osteoporosis might benefit from more careful and extensive surgical procedures rather than curettage performed with the patient under local anesthesia.

The effect of boron on alveolar bone loss in osteoporotic rats

BACKGROUND/PURPOSE

The aim of this study is to investigate the effects of systemically administered boric acid on osteoporosis-related bone alterations, alveolar bone loss, receptor activator of nuclear factor kappa-b ligand (RANKL) expressions, and mandibular bone density in experimental periodontitis model in osteoporotic rats.

MATERIALS AND METHODS

Thirty-six male Wistar rats were separated into five study groups: nonligated control (C, n = 6) group; periodontitis (P, n = 6) group; osteoporosis (O, n = 8) group; osteoporosis + periodontitis (O+P, n = 8) group, and osteoporosis + periodontitis with 50 mg/kg/d boric acid (BA50, n = 8) group for 15 days. Osteoporosis was created with intraperitoneal injection of 80 mg/kg retinoic acid for 15 days. Silk ligatures (4/0) were placed around the mandibular right first molar teeth to induce experimental periodontitis. After induction of osteoporosis and periodontitis, rats were sacrificed at Day 15. Alveolar bone loss was evaluated with a stereomicroscope by measuring the distance from the cement-enamel junction to the alveolar crest. Density measurements were performed on radiographs. RANKL and tartrate-resistant acid phosphatase (TRAP) staining were performed on histological slides.

RESULTS

Alveolar bone loss was significantly higher in the O+P group than those of the other groups (P < 0.05). Boric acid decreased bone loss (P < 0.05). TRAP + osteoclast numbers were highest in the P group and lowest in the control group. The differences in TRAP + osteoclast numbers among control, P, O+P, and BA50 groups were significant (P < 0.05). There were no significant differences in RANKL expression and mandibular bone density (P > 0.05).

CONCLUSION

Within limitations of this study, we conclude that boric acid may decrease alveolar bone loss in a rat model with periodontitis and osteoporosis.

Hyperbaric oxygen therapy and osteonecrosis

Osteonecrosis of the jaw may be caused by radiation, medication, or infection. Optimal therapy requires a multimodal approach that combines surgery with adjuvant treatments. This review focuses on the use of adjunctive hyperbaric oxygen therapy for this condition. In addition to evidence regarding the basic and clinical science behind hyperbaric oxygen therapy, controversies in the field and economic implications are discussed.

Interventions for treating bisphosphonate-related osteonecrosis of the jaw (BRONJ)

BACKGROUND

Bisphosphonate drugs can be used to prevent and treat osteoporosis and to reduce symptoms and complications of metastatic bone disease; however, they are associated with a rare but serious adverse event: osteonecrosis of the maxillary and mandibular bones. This condition is called bisphosphonate-related osteonecrosis of the jaw or BRONJ. BRONJ is diagnosed when people who are taking, or have previously taken, bisphosphonates have exposed bone in the jaw area for more than eight weeks in the absence of radiation treatment. There is currently no "gold standard" of treatment for BRONJ. The three broad categories of intervention are conservative approaches (e.g. mouth rinse, antibiotics), surgical interventions and adjuvant non-surgical strategies (e.g. hyperbaric oxygen therapy, platelet-rich plasma), which can be used in combination.

OBJECTIVES

To determine the efficacy and safety of any intervention aimed at treating BRONJ.

SEARCH METHODS

We searched the following databases to 15 December 2015: the Cochrane Oral Health Group Trials Register, the Cochrane Breast Cancer Group Trials Register (20 September 2011), the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE via Ovid, EMBASE via Ovid, CancerLit via PubMed, CINAHL via EBSCO and AMED via Ovid. We scanned the references cited in retrieved articles and contacted experts in the field, the first authors of included papers, study sponsors, other bisphosphonates investigators and pharmaceutical companies. We searched for ongoing trials through contact with trialists and by searching the US National Institutes of Health Trials Register (clinicaltrials.gov) and the World Health Organization Clinical Trials Registry Platform. We also conducted a grey literature search to September 2015.

SELECTION CRITERIA

Randomised controlled trials (RCTs) comparing the effects of any treatment for BRONJ with another treatment or placebo.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened the search results, assessed the risk of bias in the included trials and extracted data. When in dispute, we consulted a third review author.

MAIN RESULTS

One small trial at high risk of bias met the inclusion criteria. The trial randomised 49 participants, most of whom had cancer. It compared standard care (defined as surgery, antibiotics and oral rinses at the discretion of the oral-maxillofacial surgeon) to standard care plus hyperbaric oxygen therapy (2 atmospheres twice a day for 40 treatments). The trial measured the percentage of participants who improved or healed at three, six, 12 and 18 months and last contact. It also measured mean weekly pain scores.At three months, the study found that the participants in intervention group were more likely to have an improvement in their osteonecrosis than the standard care group participants (risk ratio (RR) 1.94, 95% confidence interval (CI) 1.01 to 3.74). There was no clear difference between the groups for the outcome 'healed' at three months (RR 3.60, 95% CI 0.87 to 14.82). There was no clear difference between the groups for improvement or healing when they were evaluated at six, 12 and 18 months and last contact.The study did not give any information on adverse events.Although the findings suggest adjunctive hyperbaric oxygen improved BRONJ, the quality of the evidence is very low since the only study was underpowered and was at high risk of bias due to lack of blinding, cross-over of participants between groups and very high attrition (50% at 12 months and 80% at 18 months in this study, which was designed for an intended follow-up of 24 months).

AUTHORS' CONCLUSIONS

There is a lack of evidence from randomised controlled trials to guide treatment of bisphosphonate-related osteonecrosis of the jaw (BRONJ). One small trial at high risk of bias evaluated hyperbaric oxygen therapy (HBO) as an adjunct to "standard" care and could not confirm or refute the effectiveness of HBO. There are two ongoing trials of teriparatide treatment for BRONJ. We found no randomised controlled trials of any other BRONJ treatments. High quality randomised controlled trials are needed. We provide recommendations for their focus and design.

Differentiation of Bone Marrow Mesenchymal Stem Cells in Osteoblasts and Adipocytes and its Role in Treatment of Osteoporosis

Osteoporosis is a systemic metabolic bone disorder characterized by a decrease in bone mass and degradation of the bone microstructure, leaving bones that are fragile and prone to fracture. Most osteoporosis treatments improve symptoms, but to date there is no quick and effective therapy. Bone marrow mesenchymal stem cells (BMMSCs) have pluripotent potential. In adults, BMMSCs differentiate mainly into osteoblasts and adipocytes in the skeleton. However, if this differentiation is unbalanced, it may lead to a decrease in bone mass. If the number of adipocyte cells increases and that of osteoblast cells decreases, osteoporosis can result. A variety of hormones and cytokines play an important role in the regulation of BMMSCs bidirectional differentiation. Therefore, a greater understanding of the regulation mechanism of BMMSC differentiation may provide new methods to prevent and treat osteoporosis. In addition, autologous, allogeneic BMMSCs or genetically modified BMMSC transplantation can effectively increase bone mass and density, increase bone mechanical strength, correct the imbalance in bone metabolism, and increase bone formation, and is expected to provide a new strategy and method for the treatment of osteoporosis.