BACKGROUND: Medication-related osteonecrosis of the Jaw (MRONJ) is a rare but severe side effect in patients treated with medications such as Bisphosphonates (BPs). Its pathophysiological mechanism needs to be more precise. Establishing preventive measures and treatment standards is necessary. This study aimed to develop a composite hydrogel scaffold constituted by methacrylated gelatin (GelMA), methacrylated heparin (HepMA) and PRF, and investigate its potential application value in the prevention of MRONJ.
METHODS: GelMA, HepMA, and PRF were prepared using specific ratios for hydrogel scaffolds. Through mechanical properties and biocompatibility analysis, the release rate of growth factors and the ability to promote bone differentiation in vitro were evaluated. To explore the healing-enhancing effects of hydrogels in vivo, the composite hydrogel scaffold was implanted to the MRONJ rat model. Micro-computed tomography (Micro-CT) and histological examination were conducted to evaluate the bone morphology and tissue regeneration.
RESULTS: The Hep/GelMA-PRF hydrogel improved the degradation rate and swelling rate. It was also used to control the release rate of growth factors effectively. In vitro, the Hep/GelMA-PRF hydrogel was biocompatible and capable of reversing the inhibitory effect of zoledronic acid (ZOL) on the osteogenic differentiation of MC3T3-E1s. In vivo, the micro-CT analysis and histological evaluation demonstrated that the Hep/GelMA-PRF group exhibited the best tissue reconstruction. Moreover, compared to the ZOL group, the expression of osteogenesis proteins, including osteocalcin (OCN), type collagen I (Col I), and bone morphogenetic protein-2 (BMP-2) in the Hep/GelMA-PRF group were all significantly upregulated (P < 0.05).
CONCLUSIONS: The Hep/GelMA-PRF hydrogel scaffold could effectively control the release rate of growth factors, induce osteogenic differentiation, reduce inflammation, and keep a stable microenvironment for tissue repair. It has potential application value in the prevention of MRONJ.

UNASSIGNED: Zoledronate (ZA) stands as a highly effective antiresorptive agent known to trigger medication-related osteonecrosis of the jaw (MRONJ). Its clinical dosages primarily encompass those used for oncologic and osteoporosis treatments. While inflammation is recognized as a potential disruptor of mucosal healing processes associated with ZA, prior research has overlooked the influence of varying ZA dosages on tissue adaptability. Therefore, a deeper understanding of the specific mechanisms by which inflammation exacerbates ZA-induced MRONJ, particularly when inflammation acts as a risk factor, remains crucial.
UNASSIGNED: Cell proliferation and migration of human oral keratinocytes (HOK) was analyzed after treatment with different doses of ZA and/or lipopolysaccharide (LPS) to assess their possible effect on mucosal healing of extraction wounds. Mouse periodontitis models were established using LPS, and histological changes in extraction wounds were observed after the administration of oncologic dose ZA. Hematoxylin and eosin (HE) staining and immunofluorescence were used to evaluate mucosal healing.
UNASSIGNED: In vitro, LPS did not exacerbate the effects of osteoporosis therapeutic dose of ZA on the proliferation and migration of HOK cells, while aggravated these with the oncologic dose of ZA treatment by inducing mitochondrial dysfunction and oxidative stress via regulating SIRT1 expression. Furthermore, SIRT1 overexpression can alleviate this process. In vivo, local injection of LPS increased the nonunion of mucous membranes in MRONJ and decreased the expression of SIRT1, PGC-1α, and MnSOD.
UNASSIGNED: Inflammation aggravates oncologic dose of ZA-induced mitochondrial dysfunction and oxidative stress via a SIRT1-dependent pathway, enhancing the risk of impaired mucosal healing in MRONJ. Our study implies that inflammation becomes a critical risk factor for MRONJ development at higher ZA concentrations. Elucidating the mechanisms of inflammation as a risk factor for mucosal non-healing in MRONJ could inform the development of SIRT1-targeted therapies.

Osteoporosis is a prevalent bone metabolic disease that poses a significant challenge to global human health. Jaw osteoporosis, characterized by microstructural damage of the jaw resulting from various factors, is one of the common manifestations of this condition. Recent studies have demonstrated that jaw osteoporosis has multifaceted effects on oral health and can negatively impact conditions such as periodontitis, oral implantation, orthodontic treatment, and wound healing. However, there are still some limitations in the conventional treatment of osteoporosis. For instance, while bisphosphonates can enhance bone quality, they may also lead to osteonecrosis of the jaw, which poses a potential safety hazard in oral diagnosis and treatment. In recent years, considerable attention has been focused on improving the pathological condition of jaw osteoporosis. Treatment strategies such as gut microbial regulation, extracellular vesicles, molecular targeted therapy, herbal medicine, mechanical stimulation are expected to enhance efficacy and minimize adverse reactions. Therefore, understanding these effects and exploring novel treatments for jaw osteoporosis may provide new insights for oral health maintenance and disease treatment. This article reviews the impact of jaw osteoporosis on oral health and describes the limitations associated with current methods. It also discusses emerging perspectives on treatment, offering a comprehensive overview of the challenges and future directions in managing jaw osteoporosis.

This study evaluated the effectiveness of a submental island flap in closing advanced mandibular medication-related osteonecrosis of the jaw (MRONJ) wounds in patients with malignant tumors.
A total of 85 patients with stage II and III MRONJ of mandible with malignant tumor as their primary disease were retrospectively analyzed. All patients underwent surgical treatment, and the soft tissue wound closure was performed either with a submental island flap (SIF) or mucoperiosteal flap (MF). Univariate and multifactorial models were applied to analyze the factors influencing patients\' prognosis.
Univariate analysis (p = 0.004, OR 0.075-0.575, 95% CI) and binary logistic regression (p = 0.017, OR 0.032-0.713, 95% CI) suggested that the surgical prognosis of SIF wound closure was significantly better than that of MF.
Closure of wound after resection of mandibular MRONJ lesions in patients with malignant tumors using SIF had a better clinical prognosis compared with MF.

Bisphosphonate-related osteonecrosis of jaw (BRONJ) is characterized by impaired osteogenic differentiation of orofacial bone marrow stromal cells (BMSCs). Corin has recently been demonstrated to act as a key regulator in bone development and orthopedic disorders. However, the role of corin in BRONJ-related BMSCs dysfunction remains unclarified. A m6A epitranscriptomic microarray study from our group shows that the CORIN gene is significantly upregulated and m6A hypermethylated during orofacial BMSCs osteogenic differentiation. Corin knockdown inhibits BMSCs osteogenic differentiation, whereas corin overexpression or soluble corin (sCorin) exerts a promotion effect. Furthermore, corin expression is negatively regulated by bisphosphonates (BPs). Corin overexpression or sCorin reverses BPs-impaired BMSCs differentiation ability. Mechanistically, we find altered expression of phos-ERK in corin knockdown/overexpression BMSCs and BMSCs under sCorin stimulation. PD98059 (a selective ERK inhibitor) blocks the corin-mediated promotion effect. With regard to the high methylation level of corin during osteogenic differentiation, we apply a non-selective m6A methylase inhibitor, Cycloleucine, which also blocks the corin-mediated promotion effect. Furthermore, we demonstrate that METTL7A modulates corin m6A modification and reverses BPs-impaired BMSCs function, indicating that METTL7A regulates corin expression and thus contributes to orofacial BMSCs differentiation ability. To conclude, our study reveals that corin reverses BPs-induced BMSCs dysfunction, and METTL7A-mediated corin m6A modification underlies corin promotion of osteogenic differentiation via the ERK pathway. We hope this brings new insights into future clinical treatments for BRONJ.

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OBJECTIVE: This study aimed to summarize the clinical outcomes of surgical treatment for severe medication-related osteonecrosis of the jaw (MRONJ, stages 2 and 3).
METHODS: A retrospective cohort study was conducted to review the patients with severe MRONJ from July 2013 to May 2021. All patients were treated surgically. The characteristics and clinical variables were recorded and analyzed.
RESULTS: A total of 104 patients (123 MRONJ lesions) were included, including 42 males and 62 females, aged 64.6±9.1 years. The primary disease was malignant in 91 cases and benign in 13 cases. Forty-three cases (35.0%) were stage 2 lesions, and 80 (65.0%) were stage 3 lesions. Thirty-nine (31.7%) lesions were located in the maxilla, and 84 (68.3%) lesions were located in the mandible. The most commonly used bisphosphonates were zoledronic acid (n=89; 85.6%), followed by alendronate (n=10; 9.6%), and pamidronate (n=10; 9.6%). Antiangiogenic agents were administered in 62 (59.6%) patients. The mean duration of bisphosphonate therapy was 34.7±25.8 months, and the mean duration of drug holiday was 10.1±10.7 months. All operations were performed under general anesthesia. For stage 2 lesions, debridement and saucerization were performed to completely resect the lesions, and the wounds were closed without tension through local mucoperiosteum flaps. For stage 3 lesions, after the lesions were completely resected, the bone defect was covered by reconstruction plate fixation and ipsilateral submandibular gland translocation, iodoform gauze, and buccal fat pad accordingly. The follow-up period ranged from 3 months to 6 years; 81.3% (100/123) of the lesions reached mucosal healing at the last follow-up, whereas wound infection and dehiscence occurred in 18.7% (23/123) of the lesions postoperatively.
CONCLUSIONS: Severe MRONJ lesions could be surgically treated to achieve mucosal healing. Vascularized flap reconstruction could be considered if the patient\'s general condition could tolerate it.
目的: 总结晚期（2、3期）药物相关性颌骨坏死（MRONJ）的手术治疗效果。方法: 纳入2013年7月—2021年5月就诊于北京大学口腔医学院·口腔医院口腔颌面外科且采用手术治疗的晚期MRONJ患者。回顾性分析患者的临床资料，包括患者的原发疾病、用药情况、病变情况、手术治疗和随访结果等。结果: 本研究共纳入104例患者（123处病变），男性42例，女性62例，平均年龄（64.6±9.1）岁。原发疾病为恶性肿瘤91例，非肿瘤性疾病13例。2期病变43处（35.0%），3期病变80处（65.0%）。39处（31.7%）病变位于上颌骨，84处（68.3%）病变位于下颌骨。使用唑来膦酸89例（85.6%），阿仑膦酸钠10例（9.6%），帕米膦酸钠10例（9.6%），抗血管生成药物62例（59.6%）。平均药物治疗时长（34.7±25.8）月，平均停药时长（10.1±10.7）月。全部患者均在全麻下完成手术。手术去净死骨后，2期病变以局部黏骨膜瓣关闭创口，3期病变根据具体情况分别采用重建钛板联合下颌下腺转位、血管化腓骨瓣修复、碘仿纱条填塞、带蒂颊脂垫瓣修复等关闭创口。术后随访3个月至6年，81.3%（100/123）病变在末次随访时实现黏膜愈合，18.7%（23/123）病变术后复发。结论: 晚期MRONJ可以通过手术治疗实现黏膜愈合；对于合适的患者，可以考虑血管化软硬组织修复重建以提高生命质量。.

BACKGROUND: Phosphorous necrosis of the jaw (PNJ) exhibits similar clinical and pathological features as medical-related osteonecrosis of the jaw (MRONJ). This study aims at comparing the similarities and differences between PNJ and MRONJ regarding pathological features and to provide a theoretical basis for the clinical diagnosis and management of PNJ.
METHODS: A retrospective analysis was conducted to assess clinical differences among 38 PNJ patients and 31 MRONJ patients, who were diagnosed and treated between January 2009 and October 2022. Pathological alterations in bone tissue were evaluated using EDS, H&E, Masson, and TRAP staining on five specimens from both MRONJ and PNJ cases; furthermore, immunohistochemistry was used to determine the expression levels of OPG, RANKL, and Runx2. The mandibular coronoid process was removed from individuals with temporomandibular joint ankylosis to serve as a control.
RESULTS: CBCT imaging demonstrated necrotic bone formation in block, strip, or plaque shapes. EDS analysis showed that the calcium/phosphorus ratio in the bone tissue of PNJ and MRONJ was significantly lower than that of the control group (P < 0.05). Additionally, staining indicated reduced osteoblast counts, disrupted bone trabecular structure, and decreased collagen fiber content in the bone tissues of PNJ and MRONJ. Immunohistochemistry demonstrated that RANKL expression was significantly lower in MRONJ compared to PNJ and control groups (P < 0.05). Conversely, Runx2 expression was significantly higher in PNJ than in MRONJ and control groups (P < 0.05), and there was no significant difference in OPG expression.
CONCLUSIONS: PNJ and MRONJ demonstrate comparable clinical manifestations and pathological traits, although disparities may exist in their underlying exhibit comparable clinical manifestations, pathological traits, and molecular mechanisms.

OBJECTIVE: To investigate the clinical application effect of double-layer soft tissue (DLST) suture closure technique in patients with mandible medication-related osteonecrosis of the jaw (MRONJ) of early and medium stages resulted in application of anti-bone-resorptive drugs.
METHODS: Early to medium stage mandible MRONJ patients who underwent surgical treatment in the fourth ward of Peking University School and Hospital of Stomatology from October 2021 to September 2022 were included. Clinical information of the patients were collected, including primary disease, concomitant disease, medication regimen (drug type, duration of medication), MRONJ stage, clinical symptoms, imaging manifestations, etc. During surgery, after using marginal mandibulae resection to remove the necrotic bone, the wound was closed using DLST closure technique. Regular post-operative follow-up was performed to evaluate the therapeutic effect and complications of the DLST technique, the pain score and functional status of the patiens were evaluated.
RESULTS: This study totally included 13 patients, 12 women and 1 man, aged (66.69±13.14) years. Seven patients had osteoporosis, 2 had lung cancer, 3 had breast cancer and 1 had prostate cancer among their primary diseases; 7 had no concomitant diseases, 2 had diabetes mellitus, 2 had cardiovascular disease and 1 had dry syndrome. Intravenous zoledronic acid were used in 9 patients, the average duration was (37.7±20.0) months, and other drugs, such as letrozole tablets were taken in 7 patients at the same time; Denosumab injection was used in 3 patients for an average of (10.3±11.9) months; Alendronate sodium tablets were taken in 5 patients for an average of (55.20±27.20) months, and prednisone acetate tablets or acarbose tablets were taken to varying degrees in 2 patients. The average post-operative follow-up was 11.9 months (9 to 17 months), and all the 13 patients were cured without complications, such as pus overflow and so forth. The pre-operative score of Karnofsky performance status (KPS) in the patients was 68.46±14.05, and the post-operative score was 82.31±15.36, and the difference was statistically significant (P < 0.05). The pre-operative score of visual analogue scale (VAS) in the patients was 5.77±0.73 and the post-operative score was 0.38±0.51, and the difference had statistical significance (P < 0.001).
CONCLUSIONS: The double-layer soft tissue suture closure technique can achieve good clinical results in patients with MRONJ of the mandible using anti-bone-resorptive drugs alone, and can provide clinical treatment ideas for MRONJ patients with more complicated drug use.

Medication-related osteonecrosis of the jaw (MRONJ), a severe side effect caused by antiresorptive antiangiogenic medication, particularly bisphosphonates (BPs), has become a challenging disease with serious and profound effects on the physical and mental health of patients. Although it occurs with high frequency and is harmful, the exact mechanism of MRONJ remains unknown, and systematic and targeted approaches are still lacking. Maxillofacial surgeons focus on the etiology of osteonecrosis in the mandible and maxilla as well as the appropriate oral interventions for high-risk patients. Adequate nursing care and pharmacotherapy management are also crucial. This review provides a current overview of the clinicopathologic feature and research of MRONJ caused by BPs, with an emphasis on the potential mechanisms and current therapy and prevention strategies of the disease. We are of the opinion that an in-depth comprehension of the mechanisms underlying MRONJ will facilitate the development of more precise and efficacious therapeutic approaches, resulting in enhanced clinical outcomes for patients.