• Journal of the korean academy of Pediatric Dentistry
• /
• v.50 no.3
• /
• pp.307-317
• /
• 2023

Due to increasing demand for aesthetics, zirconia crowns have become a popular choice for treating primary molars. However, there is limited literature available comparing the survival rates of zirconia crowns with those of other restorative materials. The objective of this study was to compare the 36-month survival rates of zirconia crowns and stainless steel crowns for proximal caries, as well as to analyze failure types associated with each crown type. Electronic medical records and radiographs of 1,061 primary molars from 498 patients treated with 2 types of prefabricated crowns at Chosun University Dental Hospital and 2 private dental clinics between 2017 and 2019 were collected and analyzed. The survival rate of zirconia crowns was found to be lower compared to that of stainless steel crowns. Regarding the groups without pulp treatment, the survival rate of stainless steel crowns was significantly higher than that of zirconia crowns. However, in the groups that received pulp therapy, no significant difference in the survival rates was observed between the two preformed crowns. Notably, abnormal root resorption or periapical lesions were identified as the primary cause of restorative failure in stainless steel crowns, whereas loss of restoration was the predominant cause in zirconia crowns. This study holds valuable implications for clinicians when selecting preformed crowns for primary molars.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.50 no.3
• /
• pp.263-276
• /
• 2023

The purpose of this study was to evaluate the performance of a model using You Only Look Once (YOLO) for object detection of proximal caries in periapical radiographs of children. A total of 2016 periapical radiographs in primary dentition were selected from the M6 database as a learning material group, of which 1143 were labeled as proximal caries by an experienced dentist using an annotation tool. After converting the annotations into a training dataset, YOLO was trained on the dataset using a single convolutional neural network (CNN) model. Accuracy, recall, specificity, precision, negative predictive value (NPV), F1-score, Precision-Recall curve, and AP (area under curve) were calculated for evaluation of the object detection model's performance in the 187 test datasets. The results showed that the CNN-based object detection model performed well in detecting proximal caries, with a diagnostic accuracy of 0.95, a recall of 0.94, a specificity of 0.97, a precision of 0.82, a NPV of 0.96, and an F1-score of 0.81. The AP was 0.83. This model could be a valuable tool for dentists in detecting carious lesions in periapical radiographs.

• Korean Journal of Clinical Laboratory Science
• /
• v.55 no.3
• /
• pp.195-202
• /
• 2023

The caries activities of some commercially available children's beverages were measured to determine the risk of dental caries and provide basic data for preventing dental caries. For the experimental beverage, the beverages with the highest market share among carbonated beverages, fruit beverages, milk, and fermented milk products sold in the domestic market were selected. As a control, 0.25% glucose trypticase soy broth was prepared and used. The pH of the beverages, titrate acid and buffering capacity, and the acid production and vitality were measured over time after inoculating the beverages with Streptococcus mutans. The pH of children's beverages was the lowest in soda (2.61±0.02), and milk had the lowest in titratable acid (14.00±0.58). Fermented milk (80.33±3.64) had the highest buffering capacity, and carbonated beverage (9.40±1.06) had the lowest (P<0.05). Carbonated beverages (3 hr and 25 min) had the highest acid production, and milk (4 hr) had the lowest. In conclusion, thorough oral hygiene management is necessary after consuming children's beverages because they have a low pH promote high acid production of S. mutans.

• Journal of Korean society of Dental Hygiene
• /
• v.23 no.5
• /
• pp.343-350
• /
• 2023

Objectives: Water constitutes a majority of the human body and is essential for health. In addition, water intake can prevent dental caries by improving salivary lubrication and self-cleaning. This study aimed to determine the relationship between the amount of daily water intake and the symptoms of oral disease in Korean adolescents. Methods: We used data from the Korea Youth Risk Behavior Web-based Survey (KYRBS), conducted in Korea in 2021, and identified the relationship between daily water intake and oral disease symptoms in Korean adolescents. KYRBS is a nationwide cross-sectional survey conducted by the Korea Disease Control and Prevention Agency (KDCA), and a total of 54,848 participants were included in this study. Results: After adjusting for confounding factors, logistic regression analysis showed that tooth pain was more often experienced by those who drank less than two cups of water per day (odds ratio [OR]: 1.14; 95% confidence interval [CI]: 1.01-1.30) than those who drank five or more cups of water per day. Conclusions: A low daily water intake is associated with tooth pain, a symptom of dental caries. The results of our study suggest that increasing water intake may reduce dental caries. Therefore, adequate water intake may help prevent dental caries.

• The Journal of Korean Academy of Prosthodontics
• /
• v.62 no.2
• /
• pp.140-145
• /
• 2024

Removable partial denture wearers are exposed to the risks that remaining teeth get damaged by caries, attritions, erosion, and fracture. In the case of damaged abutment tooth which should fit to Removable partial denture (RPD), the fabrication of surveyed crown is followed by the making of RPD. However, making new denture takes a long time, and needs several processes and costs. Also, patients should get used to new denture. If other abutment teeth and edentulous ridges provide the existing denture with support, retention, and stability, use of existing denture is considered clinically acceptable. In this situation, fabricating retrofit crowns to an existing removable partial denture makes patient use existing denture, cuts costs, and reduces discomfort. In this case, severely worn teeth were restored using monolithic zirconia crown which fit to an existing removable partial denture by CAD-CAM. Moreover, support, retention, and stability of the denture were improved, and both doctor and patient were satisfied with the result.

• Journal of dental hygiene science
• /
• v.8 no.2
• /
• pp.81-87
• /
• 2008

The purpose of this study was to examine the oral health state, oral health awareness and oral health behavior of middle school students in a bid to raise concerns about oral health problems in a local community and help ensure the efficiency of oral health programs. The subjects in this study were 662 seventh graders in 14 different middle schools located in the city of Hwaseong. The findings of the study were as follows: Frist, In terms of indices related to dental caries, DMFT index numbered 2.0. Secondly, as to subjective oral health state, 22 percent of the boys and 10.9 percent of the girls found their own oral cavity to be healthy, and the gap between them and the others was statistically significant different(p=.000). Thirdly, in regard to tooth-related habits, the girls brushed their teeth more often than the boys(p=.000). Fourthly, for snack-intake habits, the largest number of the boys ate between meals once(42.1%), and the second largest group of them did it two or three times(31.3%). Fifthly, regarding how they felt about dental treatment, the greatest number of the boys and girls replied there's nothing special when they were asked about their mood in case of seeing a dentist next day. The second largest group answered they would get a little nervous. As to mood while waiting for treatment, the greatest number of the boys and girls answered they would get a little nervous. In regard to mood while lying on a dental chair, the largest group replied they would be nervous. Concerning mood while lying on a dental chair for scaling, most of them answered they would get nervous.

• Journal of Life Science
• /
• v.18 no.2
• /
• pp.167-174
• /
• 2008

Antimicrobial activity of Zanthoxylum piperitum was investigated against Streptococcus mutans that causes dental caries. Although the methylene chloride extract of seeds exhibited higher antimicrobial activity than other organic solvent extracts, including methanol, ethyl acetate, and hexane extracts of pericarps or seeds of Z. piperitum, essential oils prepared from both seeds and pericarps possessed more potent inhibitory activity than the methylene chloride extract of seeds. The minimal inhibitory concentrations (MICs) of the essential oils of seeds and pericarps were 0.3 mg/ml and 4.0 mg/ml against S. mutans, respectively. When the seed essential oil was further separated into seven fractions (CS-SD-A${\sim}$CS-SD-G) by thin layer chromatography (TLC), all fractions exhibited lower antimicrobial activity than the essential oil. To understand the antimicrobial ingredients of Z. piperitum, seeds the gas chromatography-mass spectrometry (GC-MS) data of the methylene chloride extract of seeds was compared with those of the seed essential oil (CS-SD). Whereas the methylene chloride extract of seeds contained carvacrol (0.24%), ${\beta}$-caryophyllene (1.72%), and ${\alpha}$-humulene (0.88%), which were previously known to inhibit growth of S. mutans, the seed essential oil contained sabinene (1.57%), linalool (1.55%), citronellal (13.67%), terpinene-4-ol (0.45%), citronellol (3.69%), geraniol (0.9%), linalyl acetate (1.35%), ${\beta}$-caryophyllene (1.35%), ${\alpha}$-humulene (0.78%), and ${\delta}$-cadinene (0.67%) in this regard. These results indicate that Z. piperitum seeds possess various inhibitory substances against S. mutans, and an effective method to isolate the active ingredients from the seeds is to prepare the essential oil. These results also suggest that the essential oil of Z. piperitium seeds may be applicable to preventing dental caries.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.36 no.1
• /
• pp.38-45
• /
• 2009

The aim of this study was to examine efficacy of the commercially available 10% CPP-ACP cream (Tooth mousse, GC Co., Japan) and/or 0.05% NaF solution on the remineralization of artifical caries-like lesion in the bovine teeth enamel. Sixty bovine teeth were embedded in orthodontic resin and flattened. The enamel surface in 3 mm diameter was exposed with nail varnish. Specimens were stored in demineralizing solution and divided 5 groups; Group 1 (No treatment), 2 (0.05% NaF solution 1 min), 3 (Tooth mousse 3 min), 4 (After 0.05% NaF solution, Tooth mousse treatment), and 5 (After Tooth mousse treatment, soaking in 0.05% NaF solution during 1 min). After treatment by groups, all specimens was stored in artificial saliva for 30 min. After the process described as above was performed during 10 days without pH cycling, surface hardness (Vickers Hardness Number, VHN) was tested and analyzed by paired t-test and one-way ANOVA test with SPSS 14.0. In intragroup comparison between surface hardness of pre and post-treatment, group 3, 4, 5 showed statistically significant increase (P < 0.05). In intergroup comparison among surface hardness increase of all groups, difference of group 5 between pre and post-treatment ($15.80{\pm}12.21$) was the highest, and followed by group 4 ($14.27{\pm}11.73$), 3 ($4.05{\pm}5.18$), 2 ($1.15{\pm}6.83$), 1 ($0.78{\pm}6.21$). Tooth mousse can be a good alternative agent for the fluoride, and the combination use with fluoride might have the additional anticariogenic effect.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.37 no.2
• /
• pp.233-239
• /
• 2010

Space loss of dental arch can appear when the proper position of teeth within the dental arch changes by a certain cause, because the balance of force makes changes about tooth position as well as alignment. The causes of space loss include proximal caries, early extraction, congenital missing of a tooth and hypodontia, etc. Among those causes of space loss, congenital missing of a tooth is more rarely observed in the primary dentition than in the permanent dentition. Congenital missing in the primary dentition is associated with that in the permanent dentition. Furthermore, it can cause space problem, such as mesial tilting or drift of adjacent teeth, space loss for permanent successors and dental arch constriction, etc. Primary lateral incisors is the most commonly involved, in the maxilla rather than in the mandible, but primary canine is rarely reported. In this patient, who visited the department of pediatric dentistry at Yonsei university dental hospital, it was observed that the maxillary right primary canine was congenitally missing and an odontoma was found insteadly. However, neither the space loss for the congenitally missing primary canine nor midline deviation is remarkable during the 2-year-10-month observation period. In addition, any clinical or radiographical symptom did not occur in spite of odontoma. Therefore, surgical enucleation of odontoma is planned according to the eruption of permanent lateral incisor or canine, unless eruption failure of permanent lateral incisor or canine nor cystic change around the odontoma is occurred. Through further evaluation, space maintainer or orthodontic treatment may be necessary.

• Journal of Life Science
• /
• v.27 no.1
• /
• pp.15-22
• /
• 2017

Streptococcus mutans (S. mutans), which plays a major role in the etiology of human dental caries, is able to tolerate exposure to acid shock in addition to its acidogenicity. We investigated the effects of pH stress on membrane fluidity, activities and expression levels of F-ATPase, and proton permeability in S. mutans. Using 1,6-diphenyl-1,3,5-hexatriene, we observed membrane ordering at pH 4.8 and pH 8.8. The ordering effects were larger at pH 4.8 in cytoplasmic membranes isolated from S. mutans (CMSM). Increasing pH resulted in a decrease in the activities and expression levels of F-ATPase. The proton permeability was decreased at both acidic and alkaline pHs, and the lowest permeability was observed at pH 4.8. The lower permeability at pH 8.8 than pH 6.8 is likely to be caused by the decreased proton influx due to the decreased CMSM fluidity. In addition, it seems to be evident that extremely low permeability at pH 4.8 was caused by the decreased proton influx due to the decreased CMSM fluidity as well as the increased proton efflux due to the increased activity and expression level of F-ATPase. It is likely that CMSM fluidity and F-ATPase activity are two major key factors that determine proton permeability in S. mutans. We suggest that CMSM fluidity plays an important role in the determination of proton permeability, which sheds light on the possibility of using nonspecific membrane fluidizers, e.g., ethanol, for anti-caries purposes.