• Microbiology and Biotechnology Letters
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• v.24 no.1
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• pp.9-18
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• 1996

Streptococcus mutans has been implicated as primary causative agents of dental caries by insoluble glucan (IG) in human and experimental animals. An attempt was made to search for the ${\alpha}$-1,3 glucanase that degrades IG produced by S. mutans. ${\alpha}$-1,3 glucanase was detected in the culture supernatant of microorganisms, which are isolated from soils on agar medium containing IG as a sole carbon source. This Streptomyces sp. hydrolysed IG produced by immobilized S. mutans and was named as Y9373. This enzyme required ${\alpha}$-1,3 glucan (IG) as an inducer. The optimum conditions for enzyme production were studied. The enzyme was purified by 30~70% $(NH_4)_2SO_4$ precipitation, anion exchange chroma tography on DEAE-cellulose and gel filtration on Sepadex G-75. The purified enzyme has a specific activity of 7840.0 U/mg protein giving 32.1-fold purification and final yield of 0.53%. The molecular weight was estimated to be about 22.5 kDa by SDS-PAGE. The optimum pH and temperature for enzyme reaction were 6.5 and 37$^{\circ}C$, respectively and the enzyme was relatively stable at the temperature below 60$^{\circ}C$. The activity of purified enzyme was enhanced by adding $Co^{2+},\;Mn^{2+}\;and\;Mg^{2+}$ into the medium, whereas inhibited by adding $Hg^{2+},\;Zn^{2+}$ and SDS. The $K_m\;and\;V_{max}$ value of ${\alpha}$-1,3 glucanase for IG were estimated to be 2.50 mM and 0.0431 mM/min, respectively. The thin layer chromatographic analysis of hydrolysates from IG with ${\alpha}$-1,3 glucanase showed that glucose was the main product of reaction. This enzyme activity was about 14 times higher than marketing dextranase as preventive agent against artificial dental caries by S. mutans in TH medium including 5% sucrose after 30 minutes.

• Journal of dental hygiene science
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• v.1 no.1
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• pp.7-11
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• 2001

Streptococcus mutans is one of the primary bacteria that cause dental caries which further result in plaque build up. Acid production resulted from carbohydrate metabolism can threaten survival of the bacteria. However some populations of S. mutans which are exposed to low acidic condition for a period of time would develop resistance and tolerance of cells to acidity that will enhance the chance of survival. Similar acid tolerances has been reported in case of Salmonella enterica serovar typhimurium, E. coli, Shigella flexneri. These acid tolerance responses(ATR) have been evolved in a similar manner as S. mutans. The protein produced in acidic condition has been proven to be important for ATR and confirmed by using chloramphenicol procedure. We hypothesize here that proteins synthesized in response to acid shock and other elements are important for ATR of cells. In this study we have confirmed that S. mutans developed acid tolerance and resistance against anaerobic condition. Mutational DNA analysis responsible for acid tolerance should be additionally required in the future. Since the development of acid tolerance that is essential for the survival of S. mutans and development of dental caries, ATR of S. mutans shoule be farther to prevent dental caries.

• Journal of dental hygiene science
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• v.4 no.1
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• pp.39-44
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• 2004

The primary purpose of this report is to investigate the index of dental caries experiences and the state of oral hygiene for the children with mental retardation, cerebral palsy, and autism. In order to get those things we investigated 99 students that ages from 8 to 13 in three special schools (which are the school for the children with mental retardation, physical difficulties, emotional disturbance). Then collected the statistics and examined if there were some regardful differences among each type. (1) The investigation shows that there is no regardful differences among them in statistice. However, the averages of their dental caries experience have a little gap. The average of the children with mental retardation group is the highest and the autistic children group is the lowest, as we can see the facts of 4.70 for group of children with mental retardation, 4.58 for group of children with cerebral palsy, 3.67 for group of autistic children, children with mental retardation group is severe, autistic children group is few. (2) The conclusion from research of oral hygiene among each type, statistically regardful differences were revealed (p<0.05). It shows children with cerebral palsy is on worst state, children with mental retardation is on next state, autistic children is on best state by compare for averages among each type, 32.30 for group of children with mental retardation 35.00 for group of children with cerebral palsy, 27.79 for autistic children.

• Journal of dental hygiene science
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• v.12 no.5
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• pp.459-468
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• 2012

This study surveyed and analyzed on the relationship between obesity and oral health in early child hood and on the oral health realities targeting 90 young children at K Child Care Center where is located in Gangwon-do Province from 10 to 11, June, 2011. As a result, DMF rate accounted for 56.7%. D rate accounted for 42.2%. The young children with the higher age, height in 100~110cm, and weight in 25 kg were indicated to be higher in DF rate than other toddlers. The young children with height in 110~115 cm were indicated to be higher in prevalence of dental caries in deciduous teeth than other young children. It was indicated that the young children in the higher age and weight leads to the higher in DFT index and DFS index. It was indicated that the young children in the more overweight leads to the higher in the index of dental caries in primary teeth, the filling deciduous teeth index, DFT index, DMFS, and DFS index. Accordingly, the child care center needs to systematically perform the oral health education and oral health management for young children, to allow Young children to acquire right food habit, and to pay close attention even to selecting snack.

• The Journal of Korea Assosiation for Disability and Oral Health
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• v.12 no.2
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• pp.96-100
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• 2016

Metachromatic leukodystrophy (MLD) is a progressive and degenerative neurological disease caused by a deficiency of the catabolic enzyme arylsulfatase A. Deficiency of arylsulfatase A results in accumulation of sulfatide in the white matter of the peripheral and central nervous system and it occurs demyelination as a result. The patient gradually goes through mental and motor failure. General symptoms of MLD include gait disturbance, mental deterioration, muscle rigidity and impaired swallowing. Inheritance of the disease is autosomal recessive. We report a dental caries treatment of a 3-year old boy with MLD. The patient underwent hematopoietic stem cell transplantation (HSCT) to slow the progression of the disease. He was suffered from difficulties of mastication and swallowing from the degenerative neurological symptom. He was ingesting food by both oral feeding and tubal feeding after he took percutaneous endoscopic gastrostomy (PEG). The cause of multiple caries was mainly presumed as patient's prolonged time of meal. The treatment was performed under general anesthesia considering patient's incompliance. Severely affected lower primary molars were treated with pulp treatment and restored with stainless steel crown. Others were restored with composite resin. There were no postoperative complications. MLD is life threatening progressive disease and also has an impact on unfavorable condition for oral health. Routine home oral care and periodic professional dental care should be emphasized to the caregiver of patient considering the susceptibility of dental caries. Not only the medical care, but periodic dental office visit would benefit the quality of life of the patient.

• The Journal of Korea Assosiation for Disability and Oral Health
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• v.15 no.1
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• pp.79-83
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• 2019

Treacher Collins syndrome(TCS) is an autosomal craniofacial development disorder which results from mutations in the gene TCOF1. Major features include midface hypoplasia, micrognathia, microtia, conductive hearing loss. Oral manifestations are characterized by cleft palate, shortened soft palate, malocclusion, anterior open bite and enamel hypoplasia. The purpose of this presentation is to describe the interesting aspects of dental treatment of a patient with TCS. A 6-year-old boy with TCS visited Seoul National University Dental Hospital for dental caries. Multiple caries was observed from clinical and radiographic examination. Because of multiple caries and behavior management ploblem, dental treatment under general anesthesia was planned. Treatment of posterior teeth was performed and some primary teeth were extracted. General anesthesia was induced and maintained with sevoflurane, nitrous oxide and oxygen. Under general anesthesia, successful dental procedure was done. Considering behavior management problem and medical condition of patient with TCS, general anesthesia can be useful.

• Journal of the korean academy of Pediatric Dentistry
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• v.47 no.4
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• pp.406-415
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• 2020

Silver diamine fluoride (SDF) is an effective and efficient agent for arresting dental caries. It can be useful in treating children with behavioral or medical limitations. The purpose of this study was to evaluate the antimicrobial effect of SDF by using salivary biofilm. Pellicle-like saliva coated structure was prepared by using unstimulated saliva. For developing cariogenic biofilm, Streptococcus mutans was added to the mixture of pooled saliva and inoculated into a saliva coated glass or chamber. SDF was applied to cariogenic biofilm to evaluate the antimicrobial effect of SDF. As time passed, total bacteria and S. mutans were reduced after application of SDF (p < 0.000). Confocal laser scanning microscope also showed the increment of the ratio of dead cell. As a result of experiment using enamel and dentin of primary teeth, it was confirmed that the growth of cariogenic biofilm was inhibited when the SDF was treated (p = 0.029 each). This study showed excellent anti-microbial effect of SDF. And anti-caries effect in clinical practice can be expected.

• The Journal of Korea Assosiation for Disability and Oral Health
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• v.14 no.1
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• pp.17-21
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• 2018

Williams syndrome (WS) is a rare congenital disorder which is caused by microdeletion of approximately 1.6 MBP from the long arm of chromosome 7 at 7q11.23. It is characterized by cardiovascular anomalies, elfin face and mental retardation. The most typical oral signs in patient with WS are hypodontia, reduced mesio-distal dimensions both in the primary and permanent teeth, macroglossia, excessive interdental spacing, enamel hypoplasia and enamel hypomineralization. The majority of children with WS have mild to moderate mental retardation, generalized anxiety disorder, hyperactivity disorder and sensitivity to sounds. The purpose of this presentation is to describe dental treatment for a child with WS. A 9-year-old boy diagnosed with WS had caries on his first permanent molars. Because of the poor cooperation, these teeth were filled temporarily with glass ionomer, and treatment under general anesthesia was planned. Under general anesthesia, caries treatment of first permanent molar and extraction of primary molar was successfully performed and there was no postoperative complications related to general anesthesia. Open bite, hypodontia, excessive dental space, enamel hypoplasia, enamel hypomineralization were observed which were characteristic in WS.

• Journal of the korean academy of Pediatric Dentistry
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• v.33 no.1
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• pp.1-12
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• 2006

The purpose of this study were to evaluate the efficacy of the newly developed Digital Imaging Fiber-Optic Trans-illumination (DIFOTI) system in detecting carious lesions in vivo as gold standard with confocal laser scanning microscopy and compared the efficacy of traditional radiography and DIFOTI system in vito as gold standard with confocal laser scanning microscopy, too. For the in vivo study, the subject pool consisted of 23 grammar school age patients just prior to entering the mixed dentition phase Each patient was given a DIFOTI examination of the anterior and posterior teeth. During $6{\sim}8$ months, the naturally expire primary teeth were collected and the efficacy of DIFOTI system was compared with confocal laser scanning microscopy. For in vitro study, 40 primary teeth were collected and decalcified by Carbopol decalcification solution for 1, 2, 4 and 8 days. Every experiment period, all teeth were DIFOTI examined and sectioned to take an image of confocal laser scanning microscopy Sensitivity and specificity were calculated from the result of DIFOTI examine and confocal laser scanning microscopy analysis. The results are as follows : 1. From the in vivo study, the sensitivity of DIFOTI examine was 0. 61 and specificity was 0.63. 2. From the in vivo study, the sensitivity of DIFOTI examine was 0.71 and specificity was 0.75.

• Journal of the korean academy of Pediatric Dentistry
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• v.29 no.1
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• pp.76-83
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• 2002

The purpose of study was to determine the effectiveness of crude IgY to S. mutans in preventing the acid production and the demineralization of primary tooth enamel in vitro. The acid production by S. mutans in Todd Hewitt broth with and without 5% sucrose was inhibited by 2.5% crude IgY, and as the concentration of crude IgY increased from 2.5% to 17.5%, the pH drop of the media after incubation continued to decrease. There were high positive correlations between the concentration of crude IgY and the pH of media in the late incubation period. The inhibition rate of demineralization of primary tooth enamel by S. mutans was determined by measuring the surface microhardness after incubation in 5% sucrose Todd Hewitt broth for 12 hours. The inhibition rate was 32.28% in 2.5% IgY, 42.28% in 7.5% IgY, 64.06% in 12.5% IgY, and 92.79% in 17.5% IgY. There was high positive correlation between the concentration of crude IgY and the surface microhardness of enamel after demineralization These results suggest that it would be possible to prevent dental caries through passive immunization using crude IgY.