Preventive dental management of osteonecrosis of the jaws related to zoledronic acid treatment

Magnesium Nanocomposite Hydrogel Reverses the Pathologies to Enhance Mandible Regeneration

The healing of bone defects after debridement in medication-related osteonecrosis of the jaw (MRONJ) is a challenging medical condition with impaired angiogenesis, susceptible infection, and pro-inflammatory responses. Magnesium (Mg) nanocomposite hydrogel is developed to specifically tackle multiple factors involved in MRONJ. Mg-oxide nanoparticles tune the gelation kinetics in the reaction between N-hydroxysuccinimide-functionalized hyperbranched poly (ethylene glycol) and proteins. This reaction allows an enhanced mechanical property after instant solidification and, more importantly, also stable gelation in challenging environments such as wet and hemorrhagic conditions. The synthesized hydrogel guides mandible regeneration in MRONJ rats by triggering the formation of type H vessels, activating Osterix+ osteoprogenitor cells, and generating anti-inflammatory microenvironments. Additionally, this approach demonstrates its ability to suppress infection by inhibiting specific pathogens while strengthening stress tolerance in the affected alveolar bone. Furthermore, the enhanced osteogenic properties and feasibility of implantation of the hydrogel are validated in mandible defect and iliac crest defect created in minipigs, respectively. Collectively, this study offers an injectable and innovative bone substitute to enhance mandible defect healing by tackling multiple detrimental pathologies.

Can medication-related osteonecrosis of the jaw be attributed to specific microorganisms through oral microbiota analyses? A preliminary study

BACKGROUND

Medication-related osteonecrosis of the jaw (MRONJ) can cause significant pain and loss of aesthetics and function if not treated properly. However, diagnosis still relies on detailed intraoral examinations and imaging. Prognosis varies even among patients with similar stages or conditions of MRONJ, emphasizing the need for a deeper understanding of its complex mechanisms. Thus, this study aimed to identify the oral microbiota of patients with MRONJ.

METHODS

This single-center prospective cohort study included patients with confirmed MRONJ who visited the Department of Oral and Maxillofacial Surgery at Yonsei University Dental Hospital between 2021 and 2022. Oral swab samples were collected from the affected and unaffected sides of each patient. The composition and enumeration of the microbial communities were analyzed, and the diversity was compared to verify ecological changes in the groups using a next-generation sequencing-based 16S metagenomic analysis. A statistical analysis was performed using Wilcoxon signed-rank test with SPSS version 22, and values of P less than 0.05 were considered statistically significant.

RESULTS

The final study sample included 12 patients. The mean age was 82.67 ± 5.73 (range, 72-90) years. Changes in microbial composition were observed at different taxonomic levels (phylum, genus, and species). The identified microorganisms were commonly associated with periodontitis, gingival disease, and endodontic infection, suggesting a multifactorial etiology of MRONJ.

CONCLUSIONS

Although this study is based on a small number of cases, it shows that MRONJ is not caused by a specific microorganism but can rather be caused by a variety of factors. By addressing these findings in large-scale studies, the significance of oral microbiome in pathogenesis can be further elucidated and can facilitate the development of effective therapeutic interventions for patients with MRONJ.

Clinical and Histopathological Aspects of MRONJ in Cancer Patients

Medication-related osteonecrosis of the jaw (MRONJ) is a major complication of bisphosphonate treatment in cancer patients, and its etiology is not completely clarified. The study's goal is to find connections between the clinical and histopathological characteristics of osteonecrosis and bisphosphonates in a cohort of cancer patients who had osteonecrosis treated surgically. The retrospective study includes 51 patients of both sexes, aged 46 to 85 years, who underwent surgical treatment for MRONJ in two oral and maxillofacial surgery clinics (Craiova and Constanța). Demographic, clinical, and imaging data from the records of patients with osteonecrosis were analyzed. The surgical treatment removed the necrotic bone, and the harvested fragments were analyzed from a histopathological perspective. The histopathological examination data were evaluated and statistically processed to look for viable bone, granulation tissue, bacterial colonies, and inflammatory infiltrate. In the study groups, MRONJ was found particularly in the posterior regions of the mandible. Tooth extraction, but also periapical or periodontal infections, represented the trigger factors in most of the cases. The surgical therapy consisted of sequestrectomy or bone resection, and the histopathological examination of the fragments revealed osteonecrosis-specific features, such as the lack of bone cells, the development of an inflammatory infiltrate, and the existence of bacterial colonies. MRONJ in cancer patients receiving zoledronic acid is a severe complication that significantly lowers quality of life. Since these patients are not usually monitored by the dentist, they are identified in advanced stages of MRONJ. For these patients, thorough dental monitoring could reduce the incidence of osteonecrosis and its related complications.

Incidence and risk factors for medication-related osteonecrosis after tooth extraction in cancer patients-A systematic review

OBJECTIVES

Antiresorptive medication has been reported to be associated with medication-related osteonecrosis of the jaw (MRONJ). This systematic review aims at investigating the incidence of and risk factors for MRONJ after tooth extractions in cancer patients treated with high-dose bisphosphonate and denosumab (BP and DS). MATERIAL AND METHODS: The protocol followed the PRISMA statement list and was registered in PROSPERO. Searches were performed for literature published up to April 2021 in the electronic databases PubMed, Embase, Web of Science, and CINAHL and then supplemented by manual research.

RESULTS

The search process resulted in 771 identified articles, of which seven studies fitted the population, intervention, comparison, and outcome framework. All were observational studies and four had control groups. A total of 550 patients treated with BP and DS were identified of whom 271 had received tooth extractions after medication onset. Due to significant heterogenicity in the collected data, only a qualitative analysis was performed. The MRONJ incidence after tooth extractions varied between 11% and 50% at the patient level. MRONJ occurred up to 3 years after the tooth extraction. Teeth affected by inflammation before the extraction and additional osteotomy during the surgical procedure were identified as risk factors.

CONCLUSIONS

Reliable methods of diagnosing MRONJ and adequate follow-up periods are important factors in obtaining the actual incidence of MRONJ after tooth extractions in patients treated with high-dose BP and DS.

Oral risk factors associated with medication-related osteonecrosis of the jaw in patients with cancer

INTRODUCTION

Bone-modifying agents (BMAs) are indispensable to cancer therapy. However, the number of patients with medication-related osteonecrosis of the jaw (MRONJ) is increasing according to the BMA administration. Oral factors predisposing to development of MRONJ are receiving attention, and oral management is recommended for prevention of MRONJ; however, the strategy and criteria have not yet been established. Therefore, we investigated the oral risk factors associated with MRONJ development in this study.

MATERIALS AND METHODS

A retrospective study was carried out on 398 cancer patients who had received oncological-dose BMAs between 2007 and 2018; general health factors, demographic, and dental factors were examined along with MRONJ development in all the patients. The cumulative occurrence rate of MRONJ was calculated using a Kaplan-Meier analysis. Clinical factors were analyzed using the Cox regression analysis.

RESULTS

MRONJ occurred in 42 of the 398 patients. The cumulative MRONJ incidence rates were 4.5, 12.9, 17.7, and 21.6% at 1, 2, 3, and 4 years, respectively. Age (p = 0.038), male sex (p = 0.002), initiation of dental interventions before BMA administration (p = 0.020), alveolar bone loss involving more than half the root (p < 0.001), and torus mandibularis (p < 0.001) were significantly associated with MRONJ.

CONCLUSIONS

Our findings suggest that patients with alveolar bone loss involving more than half the root on panoramic radiographs and torus mandibularis carry a high risk of MRONJ development. Early dental intervention before BMA administration and oral management during the treatment are important for preventing MRONJ.

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.