• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.50 no.2
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• pp.80-85
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• 2024

Objectives: To access the knowledge of undergraduate and postgraduate students of the dental college on basic anatomy, physiology, clinical examination, and pathology of the temporomandibular joint (TMJ). Materials and Methods: A total of 610 undergraduate and postgraduate students of dental college, were included in this study. The questionnaire was pretested for validation and distributed online through Google forms. Results: A pairwise comparison showed that the percentage of correct answers for interns significantly differed from that of IV Bachelor of Dental Surgery (P=0.050) and postgraduate students (P=0.048) (below average: up to 6 correct answers, good: 7-11 correct answers, excellent: 12 or more correct answers). Conclusion: TMJ diseases are common in daily life but frequently go undiagnosed and untreated due to a lack of clinical expertise. This demonstrates the necessity of providing instructions that give students in-depth knowledge and abilities for TMJ issues in clinical practice.

• Journal of Periodontal and Implant Science
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• v.50 no.5
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• pp.303-312
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• 2020

Purpose: The purpose of this study was to evaluate severe periodontitis with tooth loss as a modifiable risk factor for Alzheimer dementia (AD), vascular dementia (VaD), and mixed dementia (MD) using the National Health Insurance Service-National Health Screening Retrospective Cohort database with long-term follow-up over 14 years. Methods: Multivariate Cox hazards regression analysis was applied to a longitudinal retrospective database, which was updated in 2018, to evaluate the association between severe periodontitis with few remaining teeth and dementia after adjusting for potential risk factors, including sociodemographic factors and comorbid diseases. Results: Among 514,866 individuals in South Korea, 237,940 (46.2%) participants satisfying the inclusion criteria were selected. A total of 10,115 age- and sex-matched participants with severe periodontitis and 10,115 periodontally healthy participants were randomly selected and evenly assigned. The results showed that the risks of AD (hazard ratio [HR], 1.08), VaD (HR, 1.24), and MD (HR, 1.16) were significantly higher in patients with severe periodontitis with 1-9 remaining teeth after adjustment for sociodemographic factors, anthropomorphic measurements, lifestyle factors, and comorbidities. Conclusions: Severe periodontitis with few remaining teeth (1-9) may be considered a modifiable risk factor for the development of AD, VaD, and MD in Korean adults.

• Journal of Korean society of Dental Hygiene
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• v.17 no.1
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• pp.155-168
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• 2017

Objectives: The purpose of this research is to examine oral pathogen distribution among elderly with dementia in a care facility to understand the importance of preventively managing oral diseases in terms of preventively managing senile diseases. Methods: From 11th August 2015 to 11th October 2015, gingival crevicular fluid was collected from 130 subjects consisting of demented/non-demented elderly people aged above 65 in care facilities located in the regions of Busan/Gyeonggnam. Based on collected data, real-time PCR analysis on oral pathogen was conducted. Results: The demented elderly group consisting of female patients aged from 0 to 79 indicated higher ratios of T. denticola in comparison to the non-demented elderly group, and the demented elderly group consisting of female patients aged above 80 indicated a high ratio of S. mutans. It was confirmed that P. gingivalis and T. forsythensis categorized under the red complex are correlated, and that bacterial species categorized under the orange complex and bacterial species categorized under the red complex are correlated. Conclusions: Because eldery people with demntia are exposed to periodontal disease and dental caries, their oral environments are more vulnerable. In order to improve such environments, it is necessary to provide care facility personnel with an opportunity to receive education to become aware of the importance of oral health, and it is also necessary to compulsorily assign dental hygienists to care facilities so that they can serve as personnel specializing in oral health management.

• Journal of Korean Dental Hygiene Science
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• v.3 no.2
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• pp.51-58
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• 2020

Oral examination ensures early detection and treatment of oral diseases and improvement of quality of health-related life. This is imperative as it reduces individuals' dental medical expenses and social costs caused by diseases. However, as the low oral examination acceptance rate continues to be a problem, this study was conducted to identify the factors that influence the oral examination of an economically active population. In this study, 4,836 economically active individuals between the ages of 20 and 65 years were studied using data from the 7th National Health and Nutrition Survey in 2018. Logistic regression analysis was performed to determine the factors influencing demographic and sociological characteristics on oral examination after adjusting for complaints of mastication and speech discomfort. As a result of confirming the factors influencing the oral examination, increase in age tended to be inversely proportional to the oral examination. Income level, type of job, and job position were identified as factors that influenced oral examinations. Compared to the group with a high socioeconomic status, which is represented by a group with a high income level or a stable job type or job position, the group with low economic status was found to have a negative effect on oral examination. Oral management of vulnerable groups, who might not be considered while devising oral health management policies, should be promoted through the development and provision of oral health management policies that consider employment status and environment.

• Journal of Microbiology and Biotechnology
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• v.32 no.10
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• pp.1234-1244
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• 2022

Oral streptococci are considered as an opportunistic pathogen associated with initiation and progression of various oral diseases. However, since the currently-available treatments often accompany adverse effects, alternative strategy is demanded to control streptococci. In the current study, we investigated whether short-chain fatty acids (SCFAs), including sodium acetate (NaA), sodium propionate (NaP), and sodium butyrate (NaB), can inhibit the growth of oral streptococci. Among the tested SCFAs, NaP most potently inhibited the growth of laboratory and clinically isolated strains of Streptococcus gordonii under anaerobic culture conditions. However, the growth inhibitory effect of NaP on six different species of other oral streptococci was different depending on their culture conditions. Metabolic changes such as alteration of methionine biosynthesis can affect bacterial growth. Indeed, NaP enhanced intracellular methionine levels of oral streptococci as well as the mRNA expression level of methionine biosynthesis-related genes. Collectively, these results suggest that NaP has an inhibitory effect on the growth of oral streptococci, which might be due to alteration of methionine biosynthesis. Thus, NaP can be used an effective bacteriostatic agent for the prevention of oral infectious diseases caused by oral streptococci.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.29 no.5
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• pp.330-337
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• 2003

This is a retrospective study on the care of odontogenic infections in admission patients with major bleeding disorders. The study was based on a series of 514 patients treated at Dong San Medical Center, Wonju Christian Hospital and Il San Health Insurance Hospital, from Jan. 1, 2000, to Dec. 31, 2002. The obtained results were as follows : 1. The cardiovascular disease was the most frequent cause of the systemic diseases with major bleeding disorders, and liver disease, cerebrovascular disease and renal failure were next in order of frequency. But, there was the most frequent dental consultation in the liver disease, owing to the many odontogenic infectious diseases. 2. Male prediction (66.3%) was almost existed in the odontogenic infectious patients with major bleeding disorders. But, there was slight female prediction (53.4%) in the cardiovascular disease. 3. The most common age group of the odontogenic infectious patients with major bleeding disorders was the fifty decade(27.2%), followed by the forty, sixty & thirty decade in order. 4. In the contents of chief complaints on the odontogenic infectious patients with major bleeding disorder, peak incidence was occurred as toothache (42.2%), followed by intraoral bleeding, ulcer pain, dental extraction in order. 5. In the diagnosis group of odontogenic infectious diseases, periodontitis, pulpitis and periapical abscess were more common. 6. In the treatment group of odontogenic infectious diseases, the most frequent incidence(44.2%) was showed in primary endodontic drainage(pulp extirpation, occlusal reduction & canal opening drainage) and followed by the incision & drainage, the medications & oral hygiene instruction, scaling, indirect pulp capping in order.

• Journal of Korean society of Dental Hygiene
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• v.19 no.3
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• pp.387-397
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• 2019

Objectives: This study was conducted to examine the subjects' oral health status and changes in the oral environment after mouthwash with effervescent Vitamin C and its intake and to understand the impact on changes in the number of bacteria causing periodontal diseases in the oral cavity based on the oral health status and oral environmental condition. Methods: After obtaining approval from the Institutional Review Board of D-University, 45 people (24 in an experimental group and 21 in a control group) who participated in the oral health program were selected, among visitors of the Clinical Dental Hygienics Laboratory of D. University in B. Results: Based on the subjects' periodontal health status, the number of bacteria causing periodontal diseases in the oral cavity decreased in both experimental and control groups before and after the experiment. However, in the experimental group, it was significant when the Bleeding on Probing(BOP) level was below average, and Calculus index(CAL) was above average, in Aggregatibacter actinomycetemcomitans and the red complex. It was also significant when CAL was above average in the orange complex in the control group. Regarding bacterial changes in periodontal diseases based on the subjects' oral environmental condition, there was a significant change in the Adenosine Tri Phosphate (ATP : intraoral contaminants test) test in the oral cavity in A. actinomycetemcomitans and the red complex in the experimental group and in the O'Leary index in the control group. Further, there was a significant change in the orange complex in the ATP test in the experimental group. Conclusions: A comprehensive analysis of the results revealed that the oral health care program for dental hygiene decreased the number of bacteria causing periodontal diseases in the oral cavity in both experimental and control groups.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.37 no.1
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• pp.67-73
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• 2011

Dental bacteria can cause gum diseases, i.e. gingivitis and periodontitis, by inducing inflammation in human gingiva. Therefore, the most effective way to prevent and treat gum diseases is the control of the inflammatory reactions induced by dental bacteria. Almost all present dental care products contain anti-bacterial agents to eliminate dental bacteria. However, recent studies report that even heat-killed dental bacteria can induce the inflammation responses in oral cells. Therefore, the method using anti-bacterial agents should be improved for better anti-inflammatory effect and the effective natural anti-inflammatory substances need to be found. In addition, the mechanisms of gingival inflammation should be elucidated. In this study, we tried to find out the mechanism of the gingival inflammation and effective natural anti-inflammatory substances with human gingival epithelial cells and Prevotella intermedia which is well known as a typical dental bacteria inducing gingivitis and periodontitis. In results, Prevotell intermedia initiated the gingival inflammation response by stimulating gingival epithelial cells to release an inflammatory cytokine, IL-8. Furthermore, the inflammation by Prevotella intermedia is related to COX-2, AP-1, and TNF-${\alpha}$ pathways. Green tea extract could effectively suppress the inflammatory responses induced by Prevotella intermedia. We find out the effective natural substance for the improvement of gum diseases by studying the mechanism of the gingival inflammation induced by dental bacteria.

• International Journal of Oral Biology
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• v.42 no.4
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• pp.155-161
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• 2017

Teeth and bones are highly mineralized tissues containing inorganic minerals such as calcium phosphate, and a growing number of evidences show that their mineral content is associated with many diseases. Although the quantification of mineral contents by micro-computed tomography(micro- CT) has been used in diagnosis and evaluation for treating bone diseases, its application for teeth diseases has not been well established. In this study, we attempted to estimate a usefulness of a high-resolution micro-CT in analysis of human teeth. The teeth were scanned by using the Skyscan 1172 micro-CT. In order to measure tooth mineral content, beam hardening effect of the machine was corrected with a radiopaque iodine-containing substance, iodoacetamide. Under the maximum resolution of $6.6{\mu}m$, X-ray densities in teeth and hydroxyapatite standards were obtained with Hounsfield unit (HU), and they were then converted to an absolute mineral concentration by a CT Analyzer software. In enamel layer of cusp area, the mean mineral concentration was about $2.14mg/mm^3$ and there was a constant mineral concentration gradient from the enamel surface to the dentinoenamel junction. In the dentin of middle 1/3 of tooth, the mean mineral concentration was approximately $1.27mg/mm^3$ and there was a constant mineral concentration gradient from the outer of root to the pulp side, ranging from 1.3 to $1.06mg/mm^3$. In decay region of dentin, the mineral content was gradually decreased from the intact inner side to the decayed surface. These results suggest that high-resolution micro-CT can be as a useful tool for non-invasive measurement of mineral concentration in teeth.

• The Journal of Advanced Prosthodontics
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• v.7 no.3
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• pp.214-223
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• 2015

PURPOSE. To measure the surface loss of dental restorative zirconia and the short-term bond strength between an indirect composite resin (ICR) and zirconia ceramic after various sandblasting processes. MATERIALS AND METHODS. Three hundred zirconia bars were randomly divided into 25 groups according to the type of sandblasting performed with pressures of 0.1, 0.2, 0.4 and 0.6 MPa, sandblasting times of 7, 14 and 21 seconds, and alumina powder sizes of 50 and $110{\mu}m$. The control group did not receive sandblasting. The volume loss and height loss on zirconia surface after sandblasting and the shear bond strength (SBS) between the sandblasted zirconia and ICR after 24-h immersion were measured for each group using multivariate analysis of variance (ANOVA) and Least Significance Difference (LSD) test (${\alpha}$=.05). After sandblasting, the failure modes of the ICR/zirconia surfaces were observed using scanning electron microscopy. RESULTS. The volume loss and height loss were increased with higher sandblasting pressure and longer sandblasting treatment, but they decreased with larger powder size. SBS was significantly increased by increasing the sandblasting time from 7 seconds to 14 seconds and from 14 seconds to 21 seconds, as well as increasing the size of alumina powder from $50{\mu}m$ to $110{\mu}m$. SBS was significantly increased from 0.1 MPa to 0.2 MPa according to the size of alumina powder. However, the SBSs were not significantly different with the sandblasting pressure of 0.2, 0.4 and 0.6 MPa. The possibilities of the combination of both adhesive failure and cohesive failure within the ICR were higher with the increases in bonding strength. CONCLUSION. Based on the findings of this study, sandblasting with alumina particles at 0.2 MPa, 21 seconds and the powder size of $110{\mu}m$ is recommended for dental applications to improve the bonding between zirconia core and ICR.