Background: The first supposition of a possible relationship between occlusion and TMJ (temporomandibular joint) function was suggested by Costen, who hypothesized that changes in dental condition (loss of vertical dimension) can lead to symptoms of temporomandibular disorders (TMD). Symptoms of temporomandibular disorders are more common in women, with a female-to-male ratio ranging from 2:1 to 8:1. Temporomandibular disorders occur in 25-38% of the general population. The reason for conducting this study is that no research has been conducted in Mongolia on the relationship between malocclusion and TMJ. Aim: This study aimed to investigate the association between malocclusion and temporomandibular disorders. Materials and Methods: The study was conducted using a case-control design, and patients requiring orthodontic treat ment who visited the Orthodontics Department of the Center Hospital of the Dentistry, Mongolian National University of Medical Sciences were included in the case group, while relatively healthy individuals with normal occlusion who had not undergone orthodontic treatment were included in the control group. The sample size for each case and control group was calculated to be 20 people, for a total of 40 people aged 20-30. The need for orthodontic treatment was determined by the IOTN index (Index of Orthodontic Treatment Need). Relatively healthy occlusion was defined according to Andrew’s six keys. The condition of the temporomandibular joint was determined using a questionnaire and physical examination. Results: The mean age of the study participants was 24.4±3.7 years in the malocclusion group and 26.0±3.6 years in the control group, 45% (n=8) of the malocclusion group were male and 40% (n=9) of the control group were male. The indicators of malocclusion, such as increased overjet, decreased overjet, increased overbite and mouth breathing were statistically significantly different between the malocclusion group and the control group (p<0.05). Logistic regression analysis showed that CII (OR=11.66, p=0.007) and CIII (OR=16.33, p=0.017) occlusion, increased overbite (OR=6.87, p=0.025) and mouth breathing (OR=4.22, p=0.042) had an impact on the occurrence of TMJ noise in both vertical and horizontal directions. Conclusions 1. Among the study participants, Angle’s Class I accounted for 50% (the highest percentage), while Angle’s Class III accounted for 20% (the lowest percentage). But Angle’s Class II accounted for 30%. 2. Symptoms of temporomandibular joint disorder were statistically significantly higher in the case group (p<0.05). 3. People with Angle’s Class II and Class III were 11-16 times more likely to develop temporomandibular joint (TMJ) noise, a symptom of TMD, compared to people with normal occlusion.

Background: Sleep is a complex neuropsychological, biological, and physiological process essential to human health. Obstructive Sleep Apnea (OSA) is a highly prevalent disorder worldwide. In Asian countries, 12–40% of the population, and in the United States, 35.8% of the population are estimated to be at high risk for OSA. In Mongolia, however, there is limited research on the prevalence of OSA, which led to the initiation of this study. Aim: To determine the prevalence and risk level of OSA among the Mongolian population. Materials and Methods: A total of 1,405 individuals aged 18 and older from the clinical Mon-Timeline cohort study were assessed using the Berlin Questionnaire (BQ). The BQ evaluates three categories: snoring and witnessed apneas, daytime sleepiness, and high blood pressure and obesity. Individuals who met criteria in any two of the three categories were classified as being at high risk for OSA. Data on educational attainment and lifestyle behaviors were collected using the Food Frequency Questionnaire and the Global Physical Activity Questionnaire. Statistical analysis was performed using Student’s t-test, Pearson’s chi-square test (χ²), and ANOVA. Results: The mean age of participants was 42 ± 14.3 years, and 42.5% were male. A total of 24.3% (n=341) were found to be at high risk for OSA. The risk increased with age: 6.7% in individuals under 30, 28.3% in those aged 30–50, and 39.4% in those over 50. Participants at high risk for OSA tended to be older and more physically inactive. Additionally, 41.7% of all participants reported snoring, and 39.3% of those stated that their snoring disturbed others. Conclusion A significant portion (24.4%) of the Mongolian population is at high risk for OSA. These individuals are more likely to be older and physically inactive. The high prevalence of snoring and associated disturbances suggests a need for increased awareness, early detection, and age-targeted prevention strategies in Mongolia.

Introduction : Intravascular ultrasound (IVUS) is an advanced technology used to guide percutaneous coronary intervention (PCI) in patients with stable coronary artery disease (CAD). Goal: This study aims to describe the first successful implementation of IVUS in patients with stable CAD in Mongolia. Materials and Methods : Patients with CAD who underwent either CAG or IVUS-guided PCI were prospectively selected. All patients provided informed consent, which was approved by the Ethical Committee of the Ministry of Health of Mongolia (March 17, 2023, №23/014). For patients who underwent CAG-guided PCI, stent deployment was performed under conventional CAG guidance, while stent implantation was performed under IVUS guidance in patients who underwent IVUS-guided PCI. Stent restenosis at 1-year follow-up was selected as the primary endpoint. The differences between the CAG-guided PCI and IVUS-guided PCI groups were compared using independent sample t-tests and chi-square tests. The association between treatment strategy (CAG-guided PCI vs. IVUS-guided PCI) and all cause restenosis (the study endpoint) was analyzed. Results: A total of 51 patients with stable coronary artery disease (CAD) who underwent coronary angiography CAG guided PCI and intravascular ultrasound (IVUS)-guided PCI were included in the present study. The mean age was 63±9.44 years, with 88.2% male (n=45). In the IVUS-guided PCI group, the minimal lumen area (mm²) was 4.46±1.1, and after stenting, the minimal stent area was 8.59±0.5, showing a statistically significant difference (p<0.001). The stent restenosis rate at 1-year follow-up in the CAG-guided PCI group and the IVUS-guided PCI group were 16% and 3.84%, respectively. The restenosis rate in the IVUS-guided PCI group was lower than in the CAG-guided PCI group. Conclusion Complete expansion of the stent on the coronary artery wall is effective in improving long term outcomes of PCI, and IVUS guided coronary artery intervention has better long-term results compared to angiography-guided PCI group (96.1% vs 84%).

Background/Aims: Ledipasvir/sofosbuvir (LDV/SOF) shows high efficacy and safety in patients with genotype 1-hepatitis C virus (HCV). We aimed to investigate the efficacy and safety of LDV/SOF in real-world Mongolian patients. Methods: Between 2015 to 2019, 23 (0.5%) and 5,005 patients (99.5%) with genotype 1a and 1b HCV, respectively, were treated with a fixed-dose tablet containing 90 mg ledipasvir and 400 mg sofosbuvir for 12 weeks, and 81 patients (1.6%) with previous experience of interferon (IFN)-based treatment received additional 1,000 mg ribavirin. HCV RNA was measured at 4, 12, and 24 weeks after the first dose to determine rapid virologic response, end of treatment response (ETR), and sustained virologic response at 12 weeks after end of treatment (SVR12). Results: Most patients (n=5,008; 99.6%) achieved ETR and SVR12 without virologic relapse. Patients with genotype 1a showed low rates of ETR and SVR12 in only 16 patients (69.6%). There was no significant difference in SVR12 rate between patients regardless of IFN experience (n=81; 1.6%), cirrhosis (n=1,151; 22.9%), HCV RNA >6×106 IU/mL (n=866; 17.2%), or liver stiffness >9.6 kPa (n=1,721; 34.2%) (100.0%, 99.3%, 99.4%, and 99.4%, respectively). No severe adverse events (AEs) were reported, and there was no dose reduction or interruption due to AE. The most common AEs were headache (n=472; 9.4%), fatigue (n=306; 6.2%), abdominal discomfort (n=295; 5.9%), and skin rash (n=141; 2.8%). Conclusions LDV/SOF showed high efficacy and safety for patients with genotype 1, especially 1b HCV, in Mongolia. The real-world data might be applicable to patients in other Asian-Pacific countries.

Background: The main purpose of primary cleft palate repair is to reconstruct anatomical structure with minimal impairment of maxillary growth and normalize velopharyngeal function and feeding process. One of the most common complications after the primary cleft palate repair is velopharyngeal insufficiency, which leads to the subsequent surgery. The velopharyngeal function assessment characterizes speech development in children. Researches noted that velopharyngeal insufficiency causes in 5-86% after primary cleft palate repair. Therefore, it is essential to choose an adequate primary surgical method for each particular type of cleft palate. Objective: To compare velopharyngeal function using nasopharyngoscopy after primary CP repair Materials and Methods: The patients who with congenital cleft palate and, underwent primary cleft palate repair in the Department of Maxillo-facial surgery of the National Centre for Maternal and Child Health and had velopharyngeal function assessment were recruited to the study. Patients with wound dehiscence and oronasal fistula postoperatively were excluded from the study.
Cleft palate was classified according to the Veau system and Golding-Kushner scale of nasopharyngoscopy was used to assess patient’s velopharyngeal function in order to associate with cleft types and the primary palatoplasty techniques. Pearson’s chi-squared analysis and Fisher exact test were used for statistical analysis. Results: A total of 335 patients were included in the study. The mean age at primary palate repair was 22.9±13.6 months. There were 56, 42, 177, and 60 patients with Veau-I type, Veau-II type, Veau-III type and Veau- IV type respectively, whereas for primary palatoplasty 65 patients underwent Furlow technique, 148 patients – Mongolian technique, 108 patients – Two flap technique, 34 patients – Von Langenbeck technique.
Nasopharyngoscopy assessment of adequate velopharyngeal function was as followed as by “Furlow” technique in 89.4% cases, ”Mongolian” technique in 62.2% cases but by “Two flap” technique only in 48.1% and Von Langenbeck technique in 47.1% cases. Conclusion The Furlow and Mongolian techniques were superior for maintaining velopharyngeal function after primary palatoplasty.

Introduction: Left main coronary artery (LMCA) is a large vessel which supplies the majority of left ventricle and critical lesion at the bifurcation of LMCA can lead to life threatening condition. Therefore, percutaneous coronary intervention (PCI) on LMCA bifurcational stenosis is considered as a complex high risk indicated patient and procedure (CHIP). Goal: In this study, we investigated the impact of urgent and elective PCI on outcomes of patients with LMCA bifurcational stenosis. Materials and Methods: Patients who underwent for urgent PCI due to acute myocardial infarction (AMI) or elective PCI due to stable coronary artery disease (CAD) for their LMCA bifurcational stenosis. Any lesion with >50% stenosis on coronary angiography was considered as a critical stenosis. LMCA bifurcational stenosis was evaluated by Medina classification. Difference between urgent and elective PCI group were compared by independent sample t-test and chi-square test. Association between treatment strategy (urgent or elective PCI) and prognosis were evaluated by Cox proportional hazard regression, and survival rate was evaluated by Kaplan-Meier methods. Ethical approval was taken from the ethical committee of the Health Science University of Medical Sciences (№30/1А) in June 12, 2012. Results: A total of 82 patients with LMCA bifurcational stenosis were included (mean age 62±11, male 76.8%) and 14 of them underwent urgent PCI due to AMI and 68 of had elective PCI due to stable CAD. Patients who underwent urgent PCI had significantly higher 30-day mortality (1.5% vs. 21.4%, p<0.05) and all-cause mortality (7.4% vs. 35.7%, p<0.003) compared to the elective PCI group. Urgent PCI for LMCA bifurcational stenosis due to AMI was associated with increased risk of death (HR=3.63, 95% CI 1.02-12.9, p<0.05). Kaplan-Meier estimation showed that patients in the urgent PCI group had significantly lower survival compared to the elective PCI group. Conclusion Unanticipated urgent PCI for patients with LMCA bifurcational stenosis due to AMI is associated with higher risk of short and long-term mortality. Patients who underwent urgent PCI for LMCA bifurcational stenosis had significantly lower survival compared to elective PCI group.

Background: The development of caries is dependent on the interaction of four primary factors. These are a host (tooth surface), a substrate (food), the presence of oral bacteria, and time. Caries will not develop if any of these four primary factors are not present. Although the primary molars are naturally replaced by the age of 10–12 years, caries, pulpitis, periapical periodontitis, primary molar defects, even loss of primary molars can have adverse effects on the permanent teeth. The bite force is created by the dynamic action of the muscles during the physiologic act of mastication. Determination of individual bite force level has been widely used in dentistry, mainly to understand the mechanics of mastication for evaluation of the therapeutic effects of prosthetic devices and to provide reference values for studies on the biomechanics of prosthetic devices. Methods: The 4-5 year olds who were treated at the National University of Medical Sciences, School of Dentistry, Dental Hospital were admitted to this study. The magnitude of the bite force in Newtons (N) was measured (Occlusal Force Meter GM10) bilaterally corresponding with the 1st and 2nd primary molars using a specifically designed single tooth bite force gauge. Results: Fifty three children were included in the study. The prevalence of dental caries was found to be 66.04% respective. No significant differences were found between the male and the female in bite force and p values of the study. Analysis of variance evaluated difference among the three groups. The means of maximum bite force were 258.83, 216.43 and 189.15 N for the groups. Significant differences between first molar and second molar’s occlusal surface area were detected. The analysis of correlation showed that the caries and bite force presented weak inverse (r=-0.36) correlation. Conclusion The bite force of 4-5 years old children was independent of gender, body weight, body height and side of mastication. The bite force on teeth with caries were 189.15 N. The caries was in weak inverse correlation with the bite force quantity. The amount of bite force measured was dependent on tooth occlusal surface area.

Background: This study radiographically evaluated the performance of autologous platelet-rich plasma (PRP) applied in tooth sockets. Methods: Sixty-eightextractions of bilateral impacted mandibular third molars were performed in 30 patients. In one side the autologous platelet-rich plasma was placed and the other side was filled with a blood clot. Radiographic bone density was quantified 3 times by the same examiner at different moments using ImageJ software, and data was statistically analyzed by SPSS 24.0 software. Results: There was significantly faster bone formation in sockets treated with PRP (P<0.001). Significant healing was observed in the first month (P<0.004), second month (P< 0.001) for the PRP group. Conclusions Use of the autologous PRP method can skip the resorptive phase, and proceed bone regeneration. Thus, to prove the results histomorphometric analysis is preferred.

TMJ is a mobile organ that participatesin speaking , chewing , swallowing and other regular movements. Its special characterization and other causes lead to disorders which progress into TMD & headache and those are one of the major concerns of the modern-day1-5.TMJ pain should be differentiated from migraine dependent pain and in both cases Botox injection has recently shown good results. Our study goal was to study use of Botox injection during TMJ and Migraine pain. The study was carried out in MNUMS, School Of Dentistry, PDIC hospital amongst patients with TMJ pain which splint therapy failed to show successful results and in patients with migraine pain. All patients received BOTULAX 200 units (Botulinum Toxin Type A) 20U per 0.1 ml , injected with 1ml syringe and 31G size pin to TMJ and migraine reliantpoints , 10-50U per each spot total of 200U. 15 patients with TMJ , 15 patients with migraine pain received BOTULAX 200 units (Botulinum Toxin Type A) and tested the results after 1 month, 3 months , 6 months, and 1 year periods. The TMJ pain has completely numbed after 1 to 12 months. In patients with migraine dependent pain after 1 month of supervision the suffering has eased down but the patient’s definition of pain was on 3-4 point. After 3 months of surveillance, 15 patients with migraine dependent pain had been relieved of the pain and had not been diagnosed for the following 12 months. The result of our study shows that the Botox injection is effective during TMJ and Migraine dependent pain.