• Journal of Dental Rehabilitation and Applied Science
• /
• v.32 no.3
• /
• pp.149-157
• /
• 2016

Tooth preparation design is essential for successful laminate veneer treatment. Preservative tooth preparation limited on enamel, supra-margin advantageous for plaque control, and maintaining contact points known as a standard concept. However, the tooth preparation design has been the controversial issue. In biomechanical considerations, the incisal coverage should be decided on esthetic needs and necessity for the anterior guidance reconstruction. In occasion for sufficient enamel thickness, preparation can prolong to the palatal side but not recommended at palatal concavity. Elongation to contact point is selective option according to the cases. If an old resin restoration located at contact area, laminate veneer should cover over half area of that after surface treatment. The laminate veneer can be also selected at a partially discolored tooth root canal therapy (RCT) and at this occasion, the fiber-reinforced composite (FRC) posts are recommended.

• Journal of Oral Medicine and Pain
• /
• v.32 no.4
• /
• pp.375-381
• /
• 2007

Occlusal stabilization appliance is one of the most common treatment option for management of temporomandibular disorders. It acts in oral cavity for several hours per day, and usually it will take at least 6 months to 2 years of total wearing periods to take a treatment goal. In the oral cavity, occlusal stabilization appliance, unintentional manner, is able to acts as a reservoir of bacteria and protect bacteria from saliva and oxygen. This condition is so favorable to many bacteria such as S. mutans and other anaerobes, usually have been reported as causative factors of dental caries, periodontal disease and oral malodor. In this study, we investigated anaerobic bacteria and S. mutans count before and after occlusal stabilization appliance use to evaluate the possible role of occlusal stabilization appliance as protector of these bacteria. Four men(average 27.5 years) wore maxillary occlusal stabilization appliance at each night(average 9 hours) for 5 days. we swabbed saliva-plaque mixed sample at 3 different site(maxillary left 2nd molar, maxillary left central incisor, mandibular left 2nd molar) before and after occlusal stabilization appliance use. Each samples were plated in (1) anaerobic blood agar medium, (2) selective S. mutans medium(MS-MUTV) and incubated in anaerobic chamber($CO^2$ 10%, $37^{\circ}C$) for 72 hours. Each bacterial colony forming unit(CFU) were counted with naked eyes. From obtained data, we can conclude as follows: 1. There was some changes about anaerobic bacteria and S. mutans count in oral cavity after occlusal stabilization appliance use. 2. The number of anaerobic bacteria was significantly increased at maxillary 2nd molar(P=0.003), maxillary central incisor(P=0.020) after occlusal stabilization appliance use compared with before. 3. Occlusal stabilization appliance use itself had indirect effect to increase the number of anaerobic bacteria at other uncovered opponent tooth site. 4. The number of S. mutans was significantly increased at maxillary 2nd molar(P=0.043), maxillary central incisor (P=0.049) after occlusal stabilization appliance use compared with before. 5. Occlusal stabilization appliance use itself had not any effect on the number of S. mutans at other uncovered opponent tooth site.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.41 no.2
• /
• pp.157-165
• /
• 2014

Skeletal anchorage is recommended as an orthodontic treatment for an impacted immature permanent tooth. Among these methods, C-tube is relatively safe because it is fixed to the cortical bone of interdental and the lower part of the root with several short miniscrews, which causes less damage to the root in patients of early permanent dentition. As it can be easily bent, the traction direction can be adjusted to favorable bone density sites. However, patient cooperation is important and traction based on physiological force in order to gain root and dentoalveolar tissue development in immature permanent teeth is required. Periodic follow-ups should be mandatory.

• The Journal of the Korean Society for Microbiology
• /
• v.35 no.1
• /
• pp.77-85
• /
• 2000

Streptococcus mutans is the most important causative bacteria of dental caries among the oral bacteria. Lactococcus lactis 1370 was isolated from the oral cavity of child. The effect of Lactococcus lactis 1370 on the formation of artificial plaque by Streptococcus mutans was studied. 1. The insoluble substances and bacteria were much more attached on the wall of disposable cuvette in the culture of Streptococcus mutans than in the combined culture of Streptococcus mutans and Lactococcus lactis 1370. 2. The mean weight of produced artificial plaque on the wires in the beaker was 131.7 mg in the culture of Streptococcus mutans only, whereas being reduced to 6.4 mg in the combined culture of Streptococcus mutans and Lactococcus lactis 1370 (p<0.05). The viable cell didn't show the significant difference between them after culturing. 3. When Streptococcus mutans was cultured in the media containing culture supernatant of Lactococcus lactis 1370 cultured in M17 broth containing 0.5% yeast extract and 5% sucrose, the mean weight of produced artificial plaque was 8.0 mg on the wires, whereas being 125.4 mg in the media without culture supernatant of Lactococcus lactis 1370 (p<0.05). The viable cell didn't show the significant difference between them after culturing. 4. When Streptococcus mutans was cultured in the media containing soluble polymer produced by Lactococcus lactis 1370, the mean weight of produced artificial plaque was significantly reduced compared with being cultured in the media without soluble polymer (p<0.05). The viable cell didn't show the significant difference between them after culturing. 5. The soluble polymer produced by Lactococcus lactis 1370 was glucan. 6. The glucan produced by Lactococcus lactis 1370 was water-soluble glucan containing ${\alpha}$-1,6-glucose linkage as the main linkage. These results suggest that the artificial plaque formed by Streptococcus mutans is inhibited by water-soluble glucan produced by Lactococcus lactis 1370.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.25 no.3
• /
• pp.619-626
• /
• 1998

The critical etiologic factor in the development of dental caries is dental plaque. The main component of dental plaque is the mutan produced by Streptococcus mutans. The following results were obtained by using blue mutan to assess the factors affecting the mutan-digesting activity of Micromonospora aurantiaca isolated from oral cavity. Micromonospora aurantiaca digested more blue mutan in the minimal essential broth at pH 7.0 than at pH 5.5 or 8.5, and at $37^{\circ}C$ than at $32^{\circ}C\;or\;42^{\circ}C$. Blue mutan was similarly digested at the range of 1mM to 16mM of $CaCl_2$ and 0.1mM to 6.4 mM of $MgCl_2$, while being significantly digested at the concentration of 2.5mM of KCl. When the concentration of glucose was decreased in the minimal essential broth, the digestion of blue mutan was increased. When the culture supernatant of Micromonospora aurantiaca in the RL broth with 1% glucose or 0.5% mutan was mixed with 2 ${\times}$ BHIYS broth containing 0.5% yeast extract and 10% sucrose, the formation of artificial plaque on the orthodontic wires by Streptococcus mutans was inhibited(p<0.05). These results indicated that the production of mutanase was identified in the culture supernatant of Micromonospora aurantiaca, suppressing the formation of artificial plaque by Streptococcus mutans.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.27 no.2
• /
• pp.361-369
• /
• 2000

Enterococcus is a normal inhabitant of the human oral cavity, the vagina, and the gastrointestinal tract. Four isolates of Enterococcus in this study were identified as E. durans. These bacteria were characterized and the interaction of these bacteria with the important oral bacteria as like S. mutans and S. oralis was studied as follows. 1. The carbohydrate fermentation test and biochemical test showed similar results in 4 isolates. 2. The susceptibility test against erythromycin, penicillin, tobramycin, ampicillin, teicoplanin, ciprofloxacin, vancomycin, gentamicin, kanamycin, and streptomycin showed to be susceptible in all four isolates. 3. The optical density of absorbance at 550 nm was 1.405 in the culture of S. mutans in disposable cuvette, whereas being 0.855, 0.867, 0.797, and 1.083 in the combined culture of S. mutans and each E. durans. 4. The mean weight of produced artificial plaque on the wires in the beaker was $1566{\pm}103mg$ in culture of S. mutans only, whereas being reduced to $44{\pm}5mg,\;41{\pm}12mg,\;34{\pm}7mg,\;and\;38{\pm}12mg$ in the combined culture of S. mutans and each E. durans. The viable cells were $2.0\times10^9$ per ml in the culture of S. mutans wheras being $2.0\times10^7\;to\;6.0\times10^7$ per ml in the combined culture S. mutans and E. durans. 5. The viable cells were $2.1\times10^8$ per ml in the culture of S. oralis, wheras being $1.4\times10^7\;to\;7.0\times10^7$ per ml in the combined culture of S. oralis and E. durans. 6. Plasmid of about 60 kb was isolated in three isolates of E. durans. These results suggested that E. durans isolated from the oral cavity inhibited the replication of S. mutans and formation of artificial plaque, while inhibiting the replication of S. oralis a little.

• The Journal of Korean Academy of Prosthodontics
• /
• v.51 no.2
• /
• pp.107-112
• /
• 2013

Complications increases when crown height space is excessive and one should be careful of choosing type of fixed prosthesis in case crown height space is over 12 mm. In this condition, tooth seems to be longer, therefore, it is needed to use gingival shade in aesthetically important area for fixed prosthesis. In this case, fixed prosthesis which has inappropriate maintenance and hygiene could hold food, plaque, calculus, thus increase incidence of inflammation and infection. Moreover, it could lead to chronic inflammation and infection and in that case surgical improvement could be necessary. In present case report, gingival inflammation and swelling developed around prosthesis after having made it considering articulation and aesthetic view in patient who had excessive crown height space. Finding out that design of prosthesis is a factor to make it hard to maintain oral hygiene, a temporary prosthesis which has enough interproximal space and proper emergence profile was fabricated. After two months of observation, significant abnormal symptoms are not found and oral reconstruction is performed using fixed prosthesis with zircornia infrastructure and porcelain build-up based on convenient self hygiene design. Through serial treatment, inappropriate soft tissue response is not observed and satisfactory result in functional aspect comes out.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.42 no.1
• /
• pp.53-61
• /
• 2015

This study was conducted for the purpose of evaluating the stainless steel crowns on extracted primary molars and thus identifying frequent errors and defects. Visual assessment and micro-computed tomography (micro-CT) image analysis were performed on 97 primary molars for evaluation of the state of marginal adaptation, cement loss, secondary caries, ledge formation, attritive perforation and marginal polishing defect. The results were as follows: In the examination of object teeth by evaluation criteria, cement loss was found most frequently (98%), followed by secondary caries (42.3%), marginal polishing defect (41.2%), ledge formation (29.9%) and attritive perforation (17.5%), in this order. The cement loss at the margins showed a significant relationship with marginal gap and secondary caries: the larger the marginal gap is, the more frequent is the cement loss (p < 0.05). The average marginal gap was $0.31{\pm}0.26mm$ and showed the highest value in the maxillary 2nd primary molars. The location of the crown margin above the cementoenamel junction was found most frequently and it was found that the higher the crown margin is located, the less the marginal gap becomes (p < 0.05). In conclusion, it is thought very desirable to pay closer attention to crown margins and shapes for stainless steel crown restoration in order to minimize the marginal gaps and consequent cement loss.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.32 no.2
• /
• pp.357-369
• /
• 2005

Streptococci are Gram-positive, facultative anaerobes and have no catalase activities. Among mutans streptococci containing ${\alpha}-type$ hemolytic activity, S. mutans is a causative agent for dental caries. As well as acid production yielding the demineralization of tooth enamel, adherence and colonization of S. mutans to the teeth are also important for its virulence. These early colonization are accomplished by the bacterial fibrillar protein, Antigen I/II (Ag I/II) and glucosyltransferase (GTF). Therefore, Ag I/II and GTF are reasonable targets for the development of vaccine against S. mutans GS-5. The ag I/II and gtfD genes from S. mutans GS-5 were cloned and sequenced. Sequence analyses showed the nucleotides sequence of cloned genes had high homology to the sequences previously reported. The sequence alignment of 280 nucleotides between the cloned Ag I/II and the available sequence of the corresponding S. mutans GS-5 showed the perfect match. Comparing with the sequence of gtfD from S. mutans UA159, the corresponding nucleotide sequence of S. mutans GS-5 showed some mismatches and the mismatches introduced changes in four residues out of 105 amino acids, yielding four missense mutations.

• The Journal of Korean Society for School & Community Health Education
• /
• v.9 no.2
• /
• pp.105-118
• /
• 2008

Objectives: This study was performed in order to figure out oral health knowledge level of home room teachers of elementary schools in Daegu area. This study was conducted from March through May 2008. Methodology: A total of three hundred and ten (43 male teachers and 267 female teachers) home room teachers of elementary schools were surveyed. The collected data were analyzed by X2 test and one way ANOVA test by using SPSS 11.0 program. Results: Most oral health knowledge was obtained from dental clinics (45.8%) and mass media and books (40.0%). Many respondents reported that the main purpose of oral hygiene was prevention of periodontal diseases. The highest number of respondents reported that fluoridated tooth paste was the best for fluoride effects on teeth. 56.7% of the respondents said that they visited periodically dental clinics for dental caries prevention. The respondents did not have much knowledge about the importance of fluoride in dental caries. Many respondents did not know that the plaque is the main cause of periodontal diseases. Conclusion: Effective oral health education program should be prepared for the elementary school teachers because their knowledge levels of oral health is not sufficient for students.