Cloud-Based Multicenter Data Collection and Epidemiologic Analysis of Bisphosphonate-Related Osteonecrosis of the Jaws in a Central European Population

Role of Actinomyces spp. and related organisms in the development of medication-related osteonecrosis of the jaw (MRONJ): Clinical evidence based on a case series

Medication-related osteonecrosis of the jaw (MRONJ) is an increasingly common consequence of antiresorptive treatment, which often leads to the development of necrotic exposed bone surfaces with inflammatory processes affecting the jawbone. Although the development of MRONJ is often associated with the inflammatory response or infections caused by the colonizing members of the oral microbiota, the exact pathogenesis of MRONJ is still not fully understood. In the present paper, we aimed to provide additional, microbiological culture-supported evidence, supporting the "infection hypothesis" that Actinomyces spp. and related organisms may play an important pathogenic role in the development of MRONJ and the resulting bone necrosis. In our case series, all patients presented with similar underlying conditions and anamnestic data, and have received antiresorptive medications (bisphosphonates or a RANK ligand (RANKL) inhibitor) to prevent the occurrence or progression of bone metastases, secondary to prostate cancer. Nevertheless, a few years into antiresorptive drug therapy, varying stages of MRONJ was identified in the mentioned patients. In all three cases, quantitative microbiological culture of the necrotic bone samples yielded a complex microbiota, dominated by Actinomyces and Schaalia spp. with high colony counts. Additionally, our followed-up case series document the treatment of these patients with a combination of surgical intervention and long-term antibiotic therapy, where favourable clinical responses were seen is all cases. If the "infection hypothesis" is valid, it may have significant consequences in the preventative and therapeutic strategies associated with this disease.

Medication-Related Osteonecrosis of the Jaw in Dental Practice: A Retrospective Analysis of Data from the Milan Cohort

A retrospective analysis was performed with the aim of understanding whether the risk factors showed in the literature for medication-related osteonecrosis of the jaws (MRONJ) in cancer patients are also relevant in osteoporotic patients taking antiresorptive drugs (ARDs). Data were retrospectively pooled from health records of patients on ARDs who requested a dental visit between January 2006 and April 2020 in the Dental Unit at Fondazione Ca’ Granda IRCCS Ospedale Maggiore Policlinico, University of Milan. A total of 434 patients were included. The following variables were collected: sex, age, smoking habit, type of ARD, duration of treatment, route of administration, therapeutic indication, concurrent systemic therapies and pathologies. Statistical analysis confirmed the relevance of chemotherapy, smoking, and immunosuppressive drugs as risk factors. In addition, a higher frequency of MRONJ in osteoporotic patients was reported in our cohort in association with an immunodeficiency disorder of variable origin. In conclusion, the identification of individual risk-profile before dental treatments is crucial for prevention. Anamnesis should include main risk factors, such as immunosuppression, dental extractions, smoking, trauma, and poor dental health. Nevertheless, our suggestion for dental professionals is to conduct a complete medical history of patients who mention long-term per oral therapies with ARDs for osteoporosis. Osteoporotic, as well as cancer patients, may also benefit from periodic monitoring of the ARDs therapy in order to prevent MRONJ.

Is the Mandibular Condyle Involved in Medication-Related Osteonecrosis of the Jaw? Audit of a Single Tertiary Referral Center and Literature Review

Background:

Medication-related osteonecrosis of the jaw (MRONJ) may manifest as exposed mandible bone. Recent reviews of the incidence of MRONJ report primarily as exposed cortical bone of the mandibular body, ramus, and symphysis with no reports of condylar involvement.

Objective:

The aim of this study is to analyze the topographical incidence of MRONJ, comorbidities, demographics data, and clinical characteristics of patients diagnosed with MRONJ between 2014 and 2019 in the Maxillo-Facial Surgery Department University of Campania “Luigi Vanvitelli”, and compare these results with published reports.

Methods:

Data on 179 patients were collected for the study, including gender, age, underlying malignancy, medical history, and specific lesion location-identifying premaxilla and posterior sectors area involvement for the maxilla and symphysis, body, ramus, and condyle area for the mandible. A literature review was performed in order to compare our results with similar or higher sample sizes and find if any condylar involvement was ever reported. The research was carried out on PubMed database identifying articles from January 2003 to November 2020, where MRONJ site distribution was discussed, and data were examined to scan for condylar localization reports.

Results:

30 patients had maxillary MRONJ, 136 patients had mandibular MRONJ, and 13 patients had lesions located in both maxilla and mandible. None of the patients reported condylar involvement, neither as a single site nor as an additional localization. Literature review results were coherent to our findings showing no mention of condylar MRONJ.

Conclusion:

Results do not show reports of condylar involvement in MRONJ. Although the pathophysiology of the disease has not been fully elucidated, two possible explanations were developed: the first one based on the condyle embryogenetic origin; the second one based on the bisphosphonate and anti-resorptive medications effects on the different vascular patterns of the mandible areas.