Ozonated oil effect for prevention of medication-related osteonecrosis of the jaw (MRONJ) in rats undergoing zoledronic acid therapy.

OBJECTIVES: The aim of this study was to evaluate the preventive effect of ozonated oil on the development of MRONJ-like lesions at tooth extraction sites in rats submitted to zoledronic acid treatment. MATERIALS AND METHODS: Twelve rats were divided into two groups. Each rat received an injection of zoledronic acid solution once a week for 5 weeks before having its upper first molar extracted. In group 1, the clotted socket was maintained, while in the group 2, the socket was treated with ozonated oil for 10 min/day during 3 days. After euthanasia, block resection was performed for histological analysis. Necrotic bone was defined as the area of the bone with empty osteocyte lacunae and vital bone as the area with osteocyte-occupied lacunae. RESULTS: There was no statistically significant difference between the groups in the average area of vital bone (p = 0.2248) and the average area of necrotic bone (p = 0.1208). However, the average area of vital bone in group 1 was smaller (24.1 ± 2.9 cells/cm2) than in group 2 (26.8 ± 4.2 cells/cm2), and the average area of necrotic bone in group 1 was higher (7.0 ± 2.5 cells/cm2) than in group 2 (4.0 ± 1.1 cells/cm2), indicating that ozonated oil may reduce the development of osteonecrosis. CONCLUSIONS: Our findings suggest that ozonated oil might prevent MRONJ-like lesions at tooth extraction sites in rats submitted to a disease induction protocol. Further research should be conducted to confirm this hypothesis. CLINICAL RELEVANCE: MRONJ has been reported as a complication of surgical dental procedures, and there are currently no predictable preventive therapies.

Incidence of cancer among persons living near a municipal solid waste landfill site in Montreal, Québec.

The Miron Quarry municipal solid waste landfill site in Montreal, Québec, generates copious quantities of methane and other gases, including a rich mixture of volatile organic compounds, some of which are recognized or suspected human carcinogens. The site is the third largest in North America and is located in the center of a densely populated area. Using data from the Québec Tumour Registry, we conducted Poisson regression analyses to evaluate whether cancer incidence among persons who lived near the site was higher than expected. Potential exposure to ambient air pollutants from the site was defined in terms of a set of geographic exposure zones proximal to the site. A set of reference areas distal from the site was selected to be similar to these exposure zones with respect to several key sociodemographic factors. Risk ratios (RRs) were adjusted for age and calendar year. Among men living in the exposure zone closest to the site, elevated risks were observed for cancers of the stomach (RR = 1.3, 95% confidence interval [95% CI] = 1.0-1.5); liver and intrahepatic bile ducts (RR = 1.3, 95% CI = 0.9-1.8); and trachea, bronchus, and lung (RR = 1.1, 95% CI = 1.0-1.2). Among women, rates of stomach cancer (RR = 1.2; 95% CI = 0.9-1.5) and cervix uteri cancer were elevated (RR = 1.2, 95% CI = 1.0-1.5), but breast cancer incidence was less than expected (RR = 0.9, 95% CI = 0.9-1.0). Prostate cancer was also elevated in one of the proximal exposure subzones (RR = 1.2, 95% CI = 1.0-1.4). Further studies at this and at other landfill sites are needed to confirm or refute these observations.