Background: According to the World Health Organization’s 2022 Global Oral Health Status Report, approximately 3.5 billion people worldwide - nearly half of the global population - suffer from some form of oral disease, among which dental caries is the most prevalent, affecting close to 2 billion people in permanent teeth (global average prevalence of 29%) and 514 million people in primary teeth (global average prevalence of 43%). In Mongolia, the prevalence of dental caries also remains high: a 2017 survey of 1,754 individuals from six provinces and five districts found caries prevalence of 82.9% among children under 5 years of age, 80.9% among those under 12, 97.8% among the population aged 35-44, and 99.1% among those aged 65-74. A 2010 study among Mongolian preschool and school-age children found a caries prevalence of 87.8-90%, with S. mutans identified alone in 75% of culture-positive plaque samples and together with S. sobrinus in the remaining 25%. Given the persistently high global burden of dental caries, preventing the disease rather than merely treating it - for example through “replacement therapy,” in which a less cariogenic strain of S. mutans is used to colonize the oral cavity - requires a reliable rat model in which standard and clinical strains of S. mutans can reproducibly induce dental caries, so that the efficacy of such preventive strategies can be properly evaluated. Untreated dental caries is also estimated to impose an annual global economic burden of approximately US$387 billion in direct costs and US$323 billion in indirect costs, underscoring the growing importance of research into new preventive approaches. Aim: Development of a dental caries model caused by Streptococcus mutans infection in rat teeth. Materials and Methods: This study used an experimental research design. It was conducted from March 30 to April 14, 2021, at the Core Laboratory and the Education Laboratory of the Department of Microbiology and Infection Prevention Control of the Mongolian National University of Medical Sciences (MNUMS). Ethical approval was obtained from the Medical Ethics Review Committee under the Ministry of Health (meeting No. 02, March 18, 2019). Five 8-week-old Wistar rats were divided into four experimental groups - differing by bacterial strain (S. mutans ATCC 25175 standard strain versus a clinical isolate) and by drinking-water composition (with or without sucrose) - plus one negative control group, with one rat assigned to each group. A bacterial suspension was applied to the rats’ molar teeth with a sterile cotton swab three times daily at two-hour intervals for 28 consecutive days. Rats were lightly sedated with midazolam during application, and the suspension was applied during the daytime, when salivary flow is naturally reduced in rodents, in order to promote bacterial colonization of the tooth surface. Result: On day 28, microscopic examination of each rat’s maxillary and mandibular teeth revealed carious spots and cavities in all groups except the sucrose-free negative control. Cavities were deeper in the groups that received sucrose-supplemented drinking water, whereas the sucrose-free groups showed comparatively milder lesions, indicating that bacterial infection alone was sufficient to induce caries. Conclusion Infection of 8-week-old Wistar rats with either the standard or a clinical strain of S. mutans for 28 days successfully induced dental caries, and sucrose intake increased the severity of the lesions. This baseline model can be reproduced within a relatively short time frame and at low cost, and may be applied in future studies evaluating the efficacy of replacement-therapy strains or probiotic products against dental caries.

Background: Mongolia ranks first in the world for liver cancer incidence and mortality, with more than 95% of cases associated with hepatitis B virus infection. Healthcare professionals are considered a priority group for vaccination. Aim: To investigate the level of hepatitis B virus immunization among dental specialist physicians. Materials and Methods: This retrospective, observational, analytical cross-sectional study was conducted with approval from the Research Ethics Committee of the Mongolian National University of Medical Sciences (MNUMS). We analyzed serum test data from 76 dentists officially registered in the Dentistry residency program during the 2025–2026 academic year, assessing hepatitis B virus infection status and immunization levels. Statistical analysis of quantitative data was performed using SPSS version 27. Results: Data from 76 dentists were analyzed. The mean age was 28.5±6.2 years; by age group, 70% (n=53) were aged 20–29 years, 22.3% (n=17) were 30–39 years, and 7.8% (n=6) were over 40 years (p<0.05). By sex, 13.2% (n=10) were male (p>0.05). Among the study participants, 97.4% were HBV-negative with a mean age of 28.2±5.3 years (Median: 27.0, IQR: 24.0–31.0), whereas 2.6% were infected; the mean age of infected physicians was 43.5±2.1 years (Median: 43.5, IQR: 42.0–45.0), indicating a high and statistically significant occurrence of HBV infection in the age group over 40 years (Fisher’s exact test, p=0.05). When classified by immunity level, 29.2% (n=19) had anti-HBs levels below 10 mIU/mL (insufficient), 24.6% (n=16) had anti-HBs levels of 10–99 mIU/mL (weak), and 46.2% (n=30) had anti-HBs levels above 100 mIU/mL (adequate immunity); however, no statistically significant association was observed between age groups and protective antibody levels (Fisher’s exact test, p=0.892). Conclusion Among participants, the prevalence of hepatitis B virus infection was 2.6%, vaccination coverage was 85.5%, and anti-HBs antibody titers were adequate in 46.2%.

BACKGROUND In recent years, the new treatment and technology developing quickly however, the disease prevention therapy necessary investigate in preventive dentistry. Oil pulling is a traditional Indian folk remedy and Researchers et al previously first time investigated this method. Asokan S, Emmadi P, Chamundeswari et al have indicated the antibacterial activity of sesame oil against on oral microorganisms and found the bacterial growth decreased 20%. In our country, this has not been investigated thus . AIM The aim of this study to assess the antimicrobial efficacy of sunflower oil for reducing micro bacterial count in the oral cavity. METHODS The present study was a parallel design, double-blind, randomized clinical trial with two groups which collected from 162 dental students at the MNUMS, School of Dentistry. The participants rinsed a mouth by 10 ml oil 5 min twice a day after meal and all participants used the same teeth paste during the study period. Oral health status and plaque index were obtained and assessed at baseline and after 30 days of oil therapy . RESULTS However, the Oral health status index not reduced after 30 days. The baseline bacterial count mean of treatment group: a) 0-15 colons subgroup increased from 40.4% to 55.4%, b) 16-200 colons subgroup reduced from 33.3% to 28.6% and c) >201 colons subgroup reduced from 26,3% to 16.1%. In the control group no differences the bacterial count means on baseline and after therapy. CONCLUSION The oil rinse therapy can be used as valuable preventive agents in maintaining and improving oral health furthermore reduced plaque formation and bacterial colonization 15%.

The present study was conducted to assess relationship between drinking water fluoride levels and dental caries among 12 years old school children of 2 districts of Ulaanbaatar city, Mongolia. A cross-sectional analytical study was conducted on 533 school children aged 12 years, selected from 6 schools of 2 districts of Ulaanbaatar city. 533 children were divided into 2 groups according to the fluoride concentration of the waters. The all children were examined oral examination, dental caries was assessed by the DMF-T index. The result of the present study revealed that the caries prevalence in the study population was about 68,9%, and mean DMF-T was 3.05. Water fluoride concentration was highest in Khan-Uul district with 0.622ppm. There was highest prevalence of caries in children who consume water from filtration system in both districts.

The present study was conducted to assess relationship between drinking water fluoride levels and dental caries among 12 years old school children of 2 districts of Ulaanbaatar city, Mongolia.A cross-sectional analytical study was conducted on 533 school children aged 12 years, selected from 6 schools of 2 districts of Ulaanbaatar city. 533 children were divided into 2 groups according to the fluoride concentration of the waters. The all children were examined oral examination, dental caries was assessed by the DMF-T index.The result of the present study revealed that the caries prevalence in the study population was about 68,9%, and mean DMF-T was 3.05. Water fluoride concentration was highest in Khan-Uul district with 0.622ppm.There was highest prevalence of caries in children who consume water from filtration system in both districts.