The Comparative Analysis of the Salivary Biomarker’s level Between Different Areas with Air Pollutant PM2.5, in Ulaanbaatar, Mongolia

Abstract

Background/purpose: Ulaanbaatar, the capital of Mongolia, is one of the coldest and most polluted cities globally, with PM2.5 concentrations five times higher than WHO guidelines. PM2.5 enters the body via the respiratory tract and damages multiple organs, including the oral cavity. This study aimed to compare salivary biomarker levels among 12 year old children living in areas with different PM2.5 concentrations in Ulaanbaatar.
Materials and Methods: A cross sectional study enrolled 190 children from schools in the highest (study) and lowest (control) PM2.5 areas, selected using four year air quality data. Oral examinations followed WHO criteria, OHI S, Loe Silness gingival index, and PPD assessment. Saliva from 45 children (stratified by PM2.5 and oral health status) was analyzed for F₂ isoprostane, 8 OHdG, and TAC via ELISA. SPSS v29 was used for statistics.
Results: Caries prevalence was 91.0%, mean DMFT 5.29±3.49 and DT comprised 84.9% of DMFT. OHI S score averaged 1.85±1.29, significantly worse in the study group (p<0.01). Gingivitis affected 23.2% overall (25.2% study vs. 20.5% control). Children with PPD ≥3 mm were significantly more common in the high PM group (57.8% vs. 42.1%, p=0.040). Salivary 8 OHdG was the most sensitive combined burden marker, showing a 2.6 fold increase in the high PM+disease group versus low PM+healthy (447.63 vs. 172.22 pg/mL, p<0.001). TAC was markedly depleted in both disease groups, whereas F₂ isoprostane showed an unexpected inverse association with PM exposure.
Conclusion: Significantly higher caries/gingivitis and altered salivary biomarkers in high PM children underscore environmental factors in oral disease and the urgent need for public health action.