1.Digital and conventional workflows for complete denture retention
Buyankhishig B ; Javkhlan P ; Baatarkhuu B ; Otgonbayar B
Mongolian Journal of Health Sciences 2026;92(2):45-48
Background:
Although the prevalence of complete edentulism has decreased over the past decade, there are significant regional differences. For example, among adults aged 15 and older in the United States, the prevalence of complete edentulism is 4.9%, while in China, approximately one in four elderly individuals is completely edentulous. The primary treatment for this condition is complete dentures. Over the past ten years, the use of digital technology for fabricating complete dentures has increased substantially, prompting comparative studies between conventionally fabricated and digitally fabricated complete dentures.
Aim:
To compare the initial fit of complete maxillary dentures fabricated using digital and conventional methods, and to evaluate the dimensional changes after one month of denture use.
Materials and Methods:
This study was conducted based on the decision No. 24-25/05-02 of the Research Ethics Committee of the Mongolian National University of Medical Sciences. The study was carried out at the School of Dentistry, specifically in the Department of Prosthodontics and the Digital Technology Laboratory. A total of 30 complete dentures-15 fabricated digitally and 15 fabricated using conventional methods-were made for 15 patients with complete edentulism. Each denture was used for a period of one month, after which denture retention was re-evaluated using a force gauge (AMF500). Statistical analysis was performed using SPSS version 26.0, and differences were considered significant at p<0.05.
Result:
To compare the differences between digital and conventional methods at baseline, the Wilcoxon Signed-Rank Test was performed. The results showed a statistically significant difference (Z=-2.045, p=0.041, p<0.05). At the one-month follow-up, the Friedman test revealed a significant difference among the four groups (χ²(3)=11.40, p=0.01). Pairwise comparisons using the Wilcoxon Signed-Rank Test indicated that retention of conventional complete dentures at one month was significantly different (Z=-2.803, p=0.005), and retention of CAD/CAM-fabricated complete dentures at one month was also significantly different (Z=-2.497, p=0.013). However, comparison of baseline and one-month retention between CAD/CAM and conventional dentures showed no statistically significant difference (p=0.059).
Conclusion
At baseline, retention of conventional complete dentures was statistically higher compared to CAD/CAM-fabricated dentures. At the one-month follow-up, retention improved for both conventional and digital dentures.
2.The results of a comparative study on the bacterial activity of some honey trade in Mongolia
Gerelmaa E ; Nomin B ; Otgonjargal B ; Tsend-Ayush D ; Buyankhishig T ; Enkh-Amar B ; Oyunbaatar A ; Anuujin G
Mongolian Journal of Health Sciences 2026;92(2):62-66
Background:
Numerous international studies have established that the antibacterial activity of honey is attributed to its key components, including hydrogen peroxide, methylglyoxal, peptides, polyphenolic compounds, high sugar content, and acidic pH. Despite the vast consumption of different types of honey in Mongolia, there is a lack of sufficient scientific evidence on their antibacterial properties, which served as the rationale for conducting this study.
Aim:
A study comparing the antibacterial activity of honey commonly traded in Mongolia.
Materials and Methods:
The study was conducted using an experimental research design. Eight standard pathogenic bacterial strains were utilized: Pseudomonas aeruginosa ATCC 27853, Escherichia coli ATCC 25922, Klebsiella pneumoniae ATCC 1706, Staphylococcus aureus ATCC 25923, Methicillin-resistant Staphylococcus aureus (MRSA) ATCC 700699, Staphylococcus epidermidis ATCC 35984, Salmonella enterica ATCC 13076, and Acinetobacter baumannii ATCC 19606. A total of 14 honey samples were selected for the study, comprising 11 samples sourced from the Uvs, Tuv, Sukhbaatar, Khentii, Dornod, Darkhan, Selenge, and Khuvsgul provinces of Mongolia, and 3 Manuka-type honey samples from Australia. The samples were serially diluted in broth using a 96-well U-bottom microtiter plate. One microliter of each bacterial suspension was added, and the plates were incubated at 37°C for 18–24 hours. Subsequently, the cultures were spread onto Mueller-Hinton agar and incubated under the same conditions. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined by evaluating bacterial growth inhibition and bactericidal activity, respectively.
Result:
Among the tested samples, the Manuka honey with MGO 570 and the honey collected from Tumentsogt soum in Sukhbaatar province exhibited the most potent antibacterial activity against MRSA, with a minimum inhibitory concentration (MIC) of 12.5% (v/v) and a minimum bactericidal concentration (MBC) of 25% (v/v). In contrast, the antibacterial activity of Manuka honey with UMF 5 and the honeys sourced from Tuv, Uvs, and Khalkhgol soum in Dornod province demonstrated MIC and MBC values of 25% (v/v) and 50% (v/v), respectively. The Manuka honey with MGO 30, as well as the honeys collected from Selenge, Darkhan, Sukhbaatar, Khentii, and Rashaant and Tarialan soums in Khuvsgul province, showed comparatively weaker activity against MRSA, Salmonella enterica, Staphylococcus epidermidis, Escherichia coli, and Staphylococcus aureus.
Conclusion
1. The antibacterial activity of natural and cultivated floral honeys was assessed by determining their minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) against eight standard bacterial strains.
2. All seven natural floral honey samples exhibited measurable antibacterial effects against the tested strains, whereas some of the cultivated floral honey samples showed no observable activity against certain bacterial strains.
3.CAD/CAM and conventional workflows for complete denture retention
Buyankhishig B ; Javkhlan P ; Baatarkhuu B ; Otgonbayar B
Mongolian Journal of Health Sciences 2026;93(3):132-135
Background:
In the field of oral and maxillofacial prosthetics, implant-supported or tooth-supported prostheses have been proven to be an effective treatment option for patients with partial edentulism. However, complete dentures remain the sole treatment option for fully edentulous patients. Over the past decade, the use of CAD/CAM technology for fabricating complete dentures has increased substantially, leading to a growing number of studies comparing conventional complete dentures with those produced using CAD/CAM. In our country, however, there is a scarcity of research comparing the retention of maxillary complete dentures fabricated by conventional and CAD/CAM methods.
Aim:
To compare the retention of maxillary complete dentures fabricated by CAD/CAM and conventional methods.
Materials and Methods:
This study was conducted using a clinical trial design. The research was carried out at the Department of Prosthodontics, School of Dentistry, Mongolian National University of Medical Sciences (MNUMS), utilizing the Digital Technology Laboratory. The retention of 15 maxillary complete dentures fabricated by CAD/CAM and conventional methods was measured using a force gauge (AMF500). Statistical analysis was performed using SPSS version 26.0, and differences were considered statistically significant at p<0.05.
Result:
The mean retention of maxillary complete dentures fabricated by the conventional method (8.85±9.10N) was higher than that of dentures fabricated by the CAD/CAM method (4.95±2.57N). To assess the difference between the two fabrication methods, the Wilcoxon Signed Ranks Test was performed. The results showed Z=-2.045, p=0.041 (p<0.05), indicating that the retention of conventional dentures was statistically significantly higher than that of CAD/CAM dentures.
Conclusion
The retention of maxillary complete dentures fabricated by the conventional method was statistically significantly higher than that of dentures fabricated by the CAD/CAM method.
4.Study on microcapsule preparation technology
Baatarbolat J ; Buyankhishig E ; Ichinkhorloo D ; Odonchimeg M ; Purevdolgor B ; Maralmaa Ts ; Shinezaya D ; Jambaninj D ; Davaadagva D ; Otgonsuren D
Mongolian Journal of Health Sciences 2026;93(3):203-210
Background:
Maintaining the concentration of a drug in the blood at a therapeutic level is crucial for enhancing treatment efficacy and reducing adverse effects. Conventional dosage forms are rapidly absorbed, causing a quick rise in the drug concentration in the blood, but it soon declines. As a result, frequent dosing is required in chronic or acute conditions. This can lead to drug concentrations exceeding therapeutic levels, increasing toxicity, or failing to reach the required level. To address these limitations, drug delivery systems (DDS) have been intensively developed over the past few decades. Among these systems, microencapsulation technology enables targeted delivery of the drug within the body, maintains stability, controls release, improves bioavailability, reduces side effects, and protects the active pharmaceutical ingredient from degradation or elimination, delivering it specifically to the necessary tissues. These characteristics provided the rationale for conducting this study.
Aim:
Select a suitable polymer for microcapsule formation, develop a production technology using the emulsion solvent evaporation method, and evaluate certain morphological characteristics of the resulting microcapsules.
Materials and Methods:
The microcapsules were prepared using an O/W emulsion solvent evaporation method. Dichloromethane (DCM) was used as the solvent, and the wall materials were solutions of chitosan (2% w/v) and gelatin (5% w/v), which are polymers combining biodegradability and biocompatibility. These solutions were mixed in a total of eight different ratios and emulsified into an aqueous phase containing polyvinyl alcohol (PVA, 1% w/v) using a high-speed homogenizer at 8000–10000 rpm to form the emulsion, followed by solvent evaporation. The resulting microcapsules were freeze-dried to obtain dry microcapsule forms. The morphology and surface structure of the microcapsules were characterized using light microscopy and scanning electron microscopy (SEM), while their size and distribution were analyzed using the ImageJ software.
Result:
To determine the optimal wall material for the microcapsules, a total of eight formulation ratios were prepared, and the emulsion stability and viscosity were evaluated. Chitosan-dominant formulations (F1, F7, F8) exhibited excessively high viscosity and a tendency for the system to thicken, which reduced the uniformity and stability of the emulsion. In contrast, formulations with low or imbalanced gelatin content (F2, F3) failed to achieve complete emulsion stabilization and showed significant phase separation. The F5 formulation demonstrated the best stability, minimal phase separation, and appropriate viscosity, making it the optimal choice for microcapsule wall preparation. The chitosan-to-gelatin ratio of 1:2 (F5 formulation) was found to be the most suitable in terms of complete microcapsule formation, spherical shape, uniform surface, and proper viscosity. Microcapsules of the F5 formulation had an average diameter of 290±30 µm, were spherical, and maintained shape stability even after freeze-drying. A microcapsule preparation technology based on the emulsion method was developed experimentally, and the most suitable conditions were established.
Conclusion
1. The results of the study indicated that a chitosan-to-gelatin ratio of 1:2 was the most suitable formulation for microcapsules in terms of complete formation, spherical shape, and uniform surface characteristics.
2. When the gelatin content increased, microcapsule morphology deteriorated and aggregation tendencies were observed, whereas higher chitosan content increased the viscosity of the solution, which affected the stability of the emulsion and resulted in non-uniform microcapsule sizes.
3. The 1:2 chitosan-gelatin ratio is therefore crucial for microcapsule preparation, and this wall composition can be applied in further studies involving drug-loaded microcapsules.
5.Results of a study on the prevalence of pulmonary tuberculosis among people with type 2 diabetes mellitus
Tsetsegtuya B ; ; Oyuntuya T ; ; Narantuya G ; Ulzii-Utas A ; Davaadulam D ; Purevsuren B ; Bolortsetseg G ; Aigul U ; Lkhagvajav N ; Ermek J ; Tsolmon B ; Oyuntugs B ; Naranzul D ; Mitarai S ; Buyankhishig B ; Sarantuya J
Mongolian Journal of Health Sciences 2025;90(6):135-140
Background:
The continuous annual increase in the prevalence of diabetes mellitus (DM) poses significant challenges not
only within our nation but also globally in the control and management of tuberculosis.
Aim:
This study aimed to determine the incidence of pulmonary tuberculosis among individuals with type 2 diabetes
mellitus (T2DM) residing in six central districts of Ulaanbaatar and to investigate associated factors.
Materials and Methods:
A cross-sectional study design was employed. Participants aged 18 years and older diagnosed
with T2DM and receiving care at endocrinology clinics in six central districts of Ulaanbaatar were selected using systematic random sampling. Presumptive TB cases were identified through a structured questionnaire and chest X-ray. Sputum
specimens were collected and subjected to smear microscopy and Xpert MTB/RIF assay for tuberculosis detection. Cases
confirmed by laboratory diagnosis, currently undergoing tuberculosis treatment and previously treated cases as per questionnaire data were classified as tuberculosis cases, and prevalence was calculated.
Results:
A total of 1,644 individuals with T2DM were enrolled in the study, of whom 836 (50.9%) were female, with
a mean age of 58 years (range 19–89). The overall prevalence of presumptive TB cases was 10.5% (n=172; 95% CI,
9.0–12.0). Among 112 suspected cases from whom sputum samples were obtained, 10 (8.9%; 95% CI, 4.9–15.7) were
laboratory-confirmed for M.tuberculosis. Notably, 7.2% (6 cases; 95% CI, 3.4–14.9) of asymptomatic individuals with
abnormal X-ray findings were diagnosed with tuberculosis. According to questionnaire responses, 9 participants (0.5%;
95% CI, 0.3–1.0) were undergoing tuberculosis treatment, and 53 (3.2%; 95% CI, 2.5–4.2) reported a previously treated
TB cases. The overall prevalence of tuberculosis among individuals with diabetes was 4.4% (n=72; 95% CI, 3.5–5.5).
Stratification by age and sex revealed a significantly higher prevalence among males (5.9%; n=48; 95% CI, 4.5–7.8)
compared to females (2.9%; 95% CI, 1.2–4.2) (p=0.002), indicating a twofold increased risk of tuberculosis in males.
Although no statistically significant differences in tuberculosis prevalence were observed across age groups (p>0.05), a
declining trend in prevalence with older age was noted.
Conclusion
The prevalence of tuberculosis among individuals with type 2 diabetes was 4.4% (n=72; 95% CI, 3.5–5.5),
with a significantly higher rate in males (p=0.002) and a decreasing trend with increasing age. Among asymptomatic
individuals exhibiting radiographic abnormalities, 7.2% were confirmed to have tuberculosis via laboratory testing
6.The results of genotype and drug resistance analysis of M. tuberculosis strains circulating in Mongolia, compared over a 10-year interval
Oyuntuya T ; Tsetsegtuya B ; Baasansuren B ; Akiko T ; Naranzul D ; Gantungalag G ; Mitarai S ; Buyankhishig B ; Sarantuya J
Mongolian Journal of Health Sciences 2025;85(1):67-73
Background:
Tuberculosis (TB) is a preventable and usually curable disease. Yet in 2022, TB was the world’s second
leading cause of death from a single infectious agent, after coronavirus disease (COVID-19)1.
Aim:
By reviving strains isolated at specific years over a 10-year interval and performing next-generation sequencing,
we can analyze their strain genotype, epidemiology, drug resistance, and dynamicsTherefore, this study was conducted
to examine the historical trends and dynamics of strain genotype, variants, and drug resistance of tuberculosis preserved
in the culture bank.
Materials and Methods::
Using a retrospective, laboratory-based research approach, 200 strains were randomly selected from over 1,000 diagnostic isolates preserved in the NTRL culture collection from 2010 and 2020. Whole-genome
sequencing (WGS) was performed using GridION from Oxford Nanopore Technologies (ONT, Oxford, UK) to analyze
these strains. The FastQ file was submitted to the International Mycobacterial Database. Strain genotypes, subtypes, gene
mutations of drug resistance, and resistance profiles were identified using TBprofiler, MTBseq, IQ-Tree (version 1.6.12),
and EPI2me software.
Results:
Of the tuberculosis strains selected for the study, 66.5% were from eight out of nine districts of Ulaanbaatar,
while 33.5% were sampled from 16 out of 21 provinces. Out of the strains analyzed, 83.9% (95% CI 78.7–89.1) belonged
to lineage 2 or the Beijing genotype, while 16.1% (95% CI 10.9–21.3) were lineage-4 or Euro-American genotype. While
the proportion of Beijing lineage strains was slightly higher and the Euro-American lineage strains slightly lower in rural
populations compared to urban populations, the difference in strain distribution between urban and rural areas was not
statistically significant (p=0.485). Among the Beijing lineage strains, only the modern Beijing sublineage (100%) was
identified. In contrast, the Euro-American lineage exhibited various sublineages: 4 (0.5%), 4.5 (1%), 4.1.2.1 (Haarlem,
3%), Latin American-Mediterranean (LAM, 7.5%), mainly T (3.5%), and S type (0.5%). Notably, the proportion of Lineage 2 strains increased from 80% in 2010 to 86% in 2020.
The overlap of the confidence intervals for 2010 (72.16%–87.84%) and 2020 (79.20%–92.80%) indicates that there has
been no significant change in the distribution of Mycobacterium tuberculosis lineages over time. The study revealed that
among the selected Mycobacterium tuberculosis strains, resistance rates to first-line anti-tuberculosis drugs were as follows: isoniazid (39%), rifampicin (21%), ethambutol (19%), and streptomycin (34%). Genotypic analysis indicated that
the Beijing lineage was predominantly associated with drug-resistant tuberculosis cases, including multidrug-resistant
(MDR), poly-drug-resistant, and mono-drug-resistant TB. Notably, the Beijing lineage accounted for 100% of pre-extensively drug-resistant (pre-XDR) TB cases. Within the Haarlem lineage, 33% were MDR-TB.
In the Latin American-Mediterranean (LAM) lineage, 13.3% were MDR-TB, 6.6% were poly-drug-resistant, and 13.3%
were mono-drug-resistant. Among the mainly T lineage, 42.8% exhibited mono-drug resistance. These findings suggest
that the distribution of M. tuberculosis lineages in the Mongolian population has remained relatively stable over time,
with no significant temporal changes.
Conclusion
The distribution of M. tuberculosis genotypes circulating among the population of Mongolia has remained
relatively stable over time, with no significant time-dependent changes. Additionally, no mutations associated with resistance to newly introduced anti-TB drugs were detected.
7.Gene mutation associated with drug resistance in M.tuberculosis strains isolated from national TB prevalence survey in Mongolia
Tsetsegtuya B ; Baasansuren E ; Oyuntuya T ; Tserelmaa B ; Gundsuren Sh ; Tsolmon B ; Naranbat N ; Tsatsralt-Od B ; Buyankhishig B ; Naranzul D
Mongolian Medical Sciences 2019;187(1):3-10
Background:
According to the First National Tuberculosis (TB) Prevalence Survey in Mongolia the prevalence of
bacteriologically-confirmed pulmonary TB among adults was 559.6 (95% CI: 454.5–664.7) per 100000
population in 2014–2015. This was three times as high as previously estimated. Nationwide anti-tuberculosis (TB) drug resistance survey was conducted in 1999 and 2007 in Mongolia. Share of multidrug resistant TB (MDR-TB) cases among newly notified TB cases increased from 1.0% in 1999 to 1.4% in 2007. Accordingly, we aimed to perform drug susceptibility test on strains isolated from TB Prevalence Survey and to determine the prevalence of drug resistant TB.
Material and Methods:
All 242 MTB strains isolated from the survey TB cases were tested GenoTypeMTBDRplus test and conventional 1st line DST on solid medium.
Result:
Conventional DST and GenoTypeMTBDRplus tests done for 93.8% (227/242) of them and 6.2% (15/242) were tested by GenoTypeMTBDRplus only. A 61.6% (95%CI 55.3-67.4) of all cases were susceptible to first line anti-TB drugs, any drug resistance and MDR-TBdetected as 38.4% (95% CI 32.5-44.7)and 9.5% (95% CI 6.4-13.9), respectively. Prevalence of MDR-TB was7.8% (95% CI 4.9-12.4) among new and 17.9% (95% CI 9.0-32.7) among previously treated cases. The 64 strains were identified as a resistant to isoniazid, 32.8% (42/64) and 65.6% (21/64) were katG, and inhAmutation, respectively. One isolate (1.6%) was mutations in both the inhAand katGgenes.The predominant mutations detected in therpoB were S531L (91.3%) among rifampicin resistant isolates and the mutation in inhAwas C–15T (100%) and katG mutation was S315T1 (100%) among isoniazid-resistant isolates.
Conclusion
Prevalence of cases with DR-TB is high among prevalent TB cases, especially prevalence of MDR-TB among new cases. In comparison to previous studies, DR-TB cases seem to be increased. Rifampicin resistant strains have a mutation of the rpoBand resistance to isoniazid is predominantly associated with the inhA mutation.
8. Liver cirrhosis, liver cancer
Undarmaa D ; Myagmardulam B ; Buyankhishig S ; Naran G
Health Laboratory 2016;5(1):52-54
9.Results of molecular genetic study of m. Tuberculosis strains isolated from specimens of mdr-tb suspects in Ulaanbaatar, Mongolia in 2009-2010
Buyankhishig B ; Oyuntuya T ; Tserelmaa B ; Naranbat N ; Sarantuya J ; Mitarai S
Mongolian Medical Sciences 2011;158(4):56-62
Bacground: DST by conventional methods takes several weeks, while early diagnosis of the disease and the rapid identification of resistant strains are essential for efficient treatment and control of the MDR strains. Rapid molecular testing of detecting MDR-TB is needed.Objective: The aim of this study was to assess performance of molecular line probe assay, Genotype16 MTBDRp/us, for rapid detection of RIF and INH resistance for M.Tuberculosis in Mongolia. The sensitivity and specificity of Genotype® MTBDRp/us to detect RIF and INH resistance-associated mutations in culture specimens and directly in smear-positive clinical specimens was examined and compared with conventional culture and drug susceptibility testing on solid medium.Material and Methods: The subjects of this study were 218 MDR-TB suspects aged 14-75 years from 8 districts in Ulaanbaatar city. The study was conducted from July 2009 to May 2010. The Genotype M. Tuberculosis drug resistance first line (MTBDR plus) assay (Hain Life-science, Nehren, Germany) was tested on directly on 41 sputum specimens and 109 clinical isolates.Results: The high correlation of the results from Genotype® MTBDRp/us and conventional drug susceptibility testing was obtained from this study. The results clearly show high performance of Genotype® MTBDRp/us with almost 100% accuracy for all the important indicators, such as sensitivity, specificity, positive and negative predictive values of detection of RIF and INH resistance. Some minor discrepancies were obtained in comparison with DNA sequencing results.Our study found that among high proportion for detection of RIF resistance, S531L mutation (MUT3 band) occurred the most commonly, with 80.0% of all RIF-resistant strains (83.6% of MDR) having the mutation. Other mutation in the 530-533 regions was common, as detected by the lack of binding to the WT8 probe in the absence of S531L mutation.In this study we observed that mutations in the promoter region of inhA gene played a major role (67.6 % (63.9% of MDR strains and 90% of INH-mono-resistant strains) had a mutation in the inhA.Conclusion: The Genotype® MTBDRp/us assay was demonstrated as a rapid, reliable and highly accurate tool for early detection of MDR-TB through examining smear positive cases enabling early start of appropriate therapeutic and public health measures to control of the spread of drug resistant M.tuberculosis in the population.
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