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The purpose of this study was to investigate the prevalence and patterns of congenitally missing teeth in permanent teeth excluding third molars, in patients aged 8 to 16 years who visited Pusan National University Dental Hospital from January 2010 to February 2021. This retrospective study evaluated tooth agenesis and the pattern of missing teeth represented by the tooth agenesis code by reviewing panoramic radiographs and electronic medical records of 11,759 patients, including 5,548 females and 6,211 males. The prevalence of congenitally missing teeth was 10.74% (females 11.95%, males 9.66%, p < 0.0001). Patients with tooth agenesis had an average of 2.22 missing teeth, and congenitally missing teeth occurred more frequently in the mandible (8.39%) than in the maxilla (4.52%, p < 0.0001). The mandibular second premolar (58.19%) was the most frequently missing tooth. The second premolar was the most frequently missing tooth in all quadrants (30.10%, 31.67%, 43.14%, and 35.59%) when a single tooth was absent, while the first and second premolars were the most commonly absent teeth (11.69%, 11.47%, 5.94%, and 5.24%) when two or more teeth were missing. In the relationship between maxillarymandibular antagonistic quadrants and full mouth, the 1st to 4th place of the missing patterns were all involved with the 1st and 2nd premolars. This study can be clinically helpful in establishing a treatment plan for patients with missing teeth. In addition, it can be used as basic data for molecular biological research to find out the relationship between tooth agenesis and specific genes.

The purpose of this study was to measure bone age using an artificial intelligence program based on the Greulich-Pyle (GP) method to find out the bone age corresponding to each stage of cervical vertebral maturation (CVM) and the middle phalanx of the third finger (MP3). This study was conducted on 3,118 patients who visited pediatric dentistry at Kyung Hee University Dental Hospital and Pusan National University Dental Hospital from 2013 to 2021. The CVM stage was divided into 5 stages according to the classification by Baccetti, and the MP3 stage was divided into 5 stages according to the methods of Hägg and Taranger. Based on the GP method, bone age was evaluated using an artificial intelligence program. The pubertal growth spurt in the CVM stage was CVM II and III. The mean bone age in CVM II was 11.00 ± 1.81 years for males and 10.00 ± 1.49 years for females, and in CVM III, 13.00 ± 1.46 years for males and 12.00 ± 1.44 years for females (p < 0.0001). The pubertal growth spurt in the MP3 stage was MP3 - G stage. The bone age at the MP3 - G stage was 13.14 ± 1.07 years for males and 11.40 ± 1.09 years for females (p < 0.0001). Bone age evaluation using artificial intelligence is worth using in clinical practice, and it is expected that a faster and more accurate diagnosis will be possible.

Function of salivary gland and saliva composition can be an indicator of individual’s health status. Recently, saliva has been thought to have a high potential for usage in the biomedical field to diagnose, evaluate, and prevent systemic health due to the technological advances in analyzing and detecting small elements such as immunological and metabolic products, viruses, microorganisms, hormones in saliva. As a diagnostic specimen, saliva has some useful advantages compared to serum. Because of simple non-invasive method, saliva sampling is quite comfort for the patient, and it doesn’t require specialists to collect samples. The possibility of infection during the collection process is also low. For this reason, proteins, genetic materials, and various biomarkers in saliva are actively being utilized on studying stress, microbiomics, genetics, and epigenetics. For the research on collecting big data related to systemic health, the needs on biobank has been focused. Regeneration of salivary gland based on tissue engineering has been also on advancement. However, there are still many issues to be solved, such as the standardization of sample collection, storage, and usage. This review focuses on the recent trends in the field of saliva research and highlight the future perspectives in biomedical and other applications.

Objectives: The purpose of this study is to develop and evaluate the performance of a model that automatically sets a region of interest (ROI) and diagnoses mesiodens in panoramic radiographs of growing children using deep learning technology. Methods: Out of 988 panoramic radiographs, 489 patients with mesiodens were classified as an experimental group, and 499 patients without mesiodens were classified as a control group. This study consists of two networks. The first network (DeeplabV3plus) is a segmentation model that uses the posterior molar space to set the ROI in the maxillary anterior region with the mesiodens in the panoramic radiograph. The second network (Inception-resnet-v2) is a classification model that uses cropped maxillary anterior teeth to determine the presence of mesiodens. The data were divided into five groups and cross-validated. Deep learning model were created and trained using Inception-ResNet-v2. The performance of the segmentation network was evaluated using accuracy, Intersection over Union (IoU), and MeanBFscore. The overall network performance was evaluated using accuracy, precision, recall, and F1-score. Results: Segmentation performance using posterior molar space in panoramic radiographs was 0.839, IoU 0.762, and MeanBFscore 0.907. The mean values of accuracy, precision, recall, F1-score, and area under the curve for the diagnosis of mesiodens using automatic segmentation were 0.971, 0.971, 0.971, 0.971, and 0.971, respectively. Conclusions: The diagnostic performance of the deep learning system using posterior molar space on the panoramic radiograph was sufficiently useful. The results of the deep learning system confirmed the possibility of complete automation of the classification of mesiodens.

The purpose of this study was to analyze the accessibility to dental facilities and the differences in chief complaints of new patients who visited Pusan National University Dental Hospital. We collected information from electronic medical records for 1,820 new patients. The accessibility was analyzed by measuring the distance from the patient’s house to the dental facilities. The distance was categorized into 10 km sections, and the presence or absence of a local pediatric dental clinic within 10 km of the patient’s house was also categorized. As the distance between the house and Pusan National University Dental Hospital increased, the proportion of patients who visited for dental caries decreased, and orthodontic treatment increased. Dental caries accounts for 27.9% of less than 10 km and 20.5% over 30 km. Orthodontic treatment accounts for 25.4% within 10 km and 27.3% more than 30 km away. The presence or absence of a local pediatric dental clinic within 10 km did not significantly affect the distribution of chief complaints. This study can be used as basic research data to establish effective treatment measures that can improve the physical and geographical accessibility of patients visiting pediatric dentistry.

This study aimed to analyze the preoperative factors of immature first molars treated with vital pulp therapy and to find out their correlation in pediatric patients. From May 2014 to January 2020, 523 patients and 1,242 immature first molars were investigated. Factors including age, sex, tooth location, Molar-incisor hypomineralization (MIH), caries cavity location, and history of previous restoration were evaluated. As a result of the study, the vital pulp therapy group had 5.56 times more MIH, 3.39 times more mesial cavities, and 8.73 times more distal cavities. In order to avoid vital pulp therapy in immature first molar, early diagnosis and active management of MIH and preventive treatment of mesial and distal caries are necessary after its immediate eruption.

The purpose of this study was to investigate the prevalence and characteristics of pre-eruptive intracoronal radiolucencies (PEIR) from panoramic radiographs in Korean children and adolescents.This study examined panoramic radiographs of 3,000 patients aged between 5 and 14 years old who visited ten dental hospitals in Korea. The age and gender of the patients, the tooth type, the number of intracoronal radiolucent lesions, and the location and size of the lesions were recorded.The overall prevalence of patients with PEIR was 2.5%. The difference in the presence of PEIR between both genders was not significant. Within each tooth type, the mandibular first molar showed highest prevalence of PEIR (29.6%). The central part of the crown was the most frequently observed location of PEIR (56.8%). The size of the PEIR lesions was mostly limited to less than one-third of the thickness of coronal dentin.

The purpose of this retrospective study was to evaluate the survival rate by comparing Class II restoration using flowable resin composite with stainless steel crown in primary molars. Electronic medical records and radiographs of 1,504 primary molars with proximal caries of 590 patients from June 2015 to August 2019 were analyzed. With the collected data, survival analysis was performed using the Kaplan-Meier method. The 1-year survival rate of flowable resin composite in the primary molar was 98.5%, 3-year survival rate was 87.7%, and mean survival time was 39 months. There was no statistically significant difference between flowable resin composite and stainless steel crown (p = 0.896). Within the limits of this study, Class II restoration using flowable resin composite can be considered a promising option for the treatment of proximal caries in primary molars.

This study was performed to evaluate the restoration combined with resin infiltration (RI) of early cavitated smooth surface caries lesion in terms of microleakage. Flowable resin and resin-modified glass ionomer cement (RMGIC) were compared.Sound 20 extracted 3rd molars were divided into 2 groups randomly. Artificial decalcified lesion was induced. Cavities were prepared on the mesial and distal surfaces, and randomly set as experimental and control group. RI was applied to the experimental group before cavity restoration. The control group was restored without RI. In group I and II, flowable resin and RMGIC was used for restoration respectively. After thermocycling and silver nitrate immersion, microleakage was assessed by μ-CT.Depth of microleakage was lower in experimental group than control group only in group II (p = 0.05). Microleakage depth was lower in group II than group I in both experimental and control groups (p = 0.05).RI pretreatment before restoration of early cavitated caries lesions might reduce the microleakage and help long-term maintenance of restoration. In this study, RMGIC was less polymerization shrinkage. Restoration with RMGIC after RI pretreatment reduced the microleakage of the restoration compared to the flowable resin.

Background The COVID-19 pandemic changed the world and created a shift in the dental education program. This sudden change in the dental education program may have affected the academic standards of dental students. This study aimed to evaluate the overall satisfaction and effectiveness of online learning in pediatric dentistry of undergraduate dental students’ during the COVID-19 pandemic in South Korea. Methods An anonymous online survey was sent to three dental schools, and responses were collected from dental school students. Questions included the demographics, perspectives of online classes, comparison of online and offline pediatric dentistry classes and opinions on how dental schools are handling the pandemic. Students’ perspectives on online classes were evaluated based on satisfaction with online education. Data were analyzed using the Kruskal-Wallis test and the Mann-Whitney U test. Results Most students took online classes from home (80.9%) using Zoom (50.4%). The majority reported overall program satisfaction (74.1%) and agreed that universities implemented online classes well (55%). Students who were in favor of online classes responded more positively to questions on the effectiveness and safety of online learning (p Conclusions Dental students in South Korea preferred and adapted well to the web-based learning program in pediatric dentistry during COVID-19 pandemic.

In this study, we aimed to develop and evaluate the performance of deep-learning models that automatically classify mesiodens in primary or mixed dentition panoramic radiographs. Panoramic radiographs of 550 patients with mesiodens and 550 patients without mesiodens were used. Primary or mixed dentition patients were included. SqueezeNet, ResNet-18, ResNet-101, and Inception-ResNet-V2 were each used to create deep-learning models. The accuracy, precision, recall, and F1 score of ResNet-101 and Inception-ResNet-V2 were higher than 90%. SqueezeNet exhibited relatively inferior results. In addition, we attempted to visualize the models using a class activation map. In images with mesiodens, the deep-learning models focused on the actual locations of the mesiodens in many cases. Deep-learning technologies may help clinicians with insufficient clinical experience in more accurate and faster diagnosis.

The purpose of this study is to evaluate and compare the performance of six state-of-the-art convolutional neural network (CNN)-based deep learning models for cervical vertebral maturation (CVM) on lateral cephalometric radiographs, and implement visualization of CVM classification for each model using gradient-weighted class activation map (Grad-CAM) technology. A total of 600 lateral cephalometric radiographs obtained from patients aged 6–19 years between 2013 and 2020 in Pusan National University Dental Hospital were used in this study. ResNet-18, MobileNet-v2, ResNet-50, ResNet-101, Inception-v3, and Inception-ResNet-v2 were tested to determine the optimal pre-trained network architecture. Multi-class classification metrics, accuracy, recall, precision, F1-score, and area under the curve (AUC) values from the receiver operating characteristic (ROC) curve were used to evaluate the performance of the models. All deep learning models demonstrated more than 90% accuracy, with Inception-ResNet-v2 performing the best, relatively. In addition, visualizing each deep learning model using Grad-CAM led to a primary focus on the cervical vertebrae and surrounding structures. The use of these deep learning models in clinical practice will facilitate dental practitioners in making accurate diagnoses and treatment plans.

이 연구의 목적은 고등학교를 졸업한지 10년 이내의 성인을 대상으로 구강보건교육 경험과 인식을 조사하여 소아와 청소년의 구강보건교육을 제고할 방안을 찾기 위함이다. 412명의 성인에게 설문지를 배포 후 회수된 설문지 중 기준에 부합하는 388명을 선정하였다. 설문 내용은 학령기 구강보건교육 경험과 인식, 구강건...

Supernumerary tooth (ST) may arise from uncertain developmental abnormalities or underlying genetic causes, and the extraction at the early age is recommended. Dental pulp stem cells (DPSCs) are the valuable resource for the regeneration of tooth and related craniofacial structures. DPSCs isolated from ST (sDPSCs) have not been fully characterized despite the potential in the applications. The objectives of this study are the efficient isolation of sDPSCs and the analysis of the properties as stem cells. sDPSCs were established by hammer-cracking and separation of the intact pulp from ST. sDPSCs in the culture were examined by light microscope and flow cytometer for the morphology and the surface marker expression. sDPSCs exhibited the cellular morphology of typical mesenchymal stem cells and expressed CD44, CD73, CD90, CD105 and CD166, but not CD14, CD34 or CD45. sDPSCs showed the differentiation potential toward osteogenic, chondrogenic and adipogenic lineages. During osteogenic differentiation, the stimulation by Oncostatin M enhanced the differentiation and significantly increased the expression of genes involved in the hard tissue repair, such as BMP2, BMP4, BMP6 and RUNX2. sDPSCs can be effectively derived from ST and displays the characteristics of mesenchymal stem cells in the maintenance and the differentiation. sDPSCs satisfies the quality as DPSCs thus provide the valuable resource to the regenerative therapy.

Ameloblastic fibro-odontoma (AFO) is a rare, benign, and mixed odontogenic tumor that consists of both ectodermal and mesenchymal elements. AFO is more prevalent in young children and adolescents than in adults and is usually found in the molar area associated with a failure of tooth eruption. The purpose of this report is to discuss the differential diagnosis and treatment of a three-year-old girl diagnosed with an AFO around a primary canine. The manifestations of the lesion resembled localized periodontal disease caused by an enamel pearl. Excision and curettage were done and the separated dental hard tissue was confirmed from the enamel structure of the primary canine. In addition to the hard tissue, pulpy and soft tissues were removed together and were histologically examined, confirming the diagnosis of AFO.

Background Muscular dystrophy ( MD ) causes a progressive cardiomyopathy characterized by diffuse fibrosis, arrhythmia, heart failure, and early death. Activation of the thromboxane‐prostanoid receptor ( TP r) increases calcium transients in cardiomyocytes and is proarrhythmic and profibrotic. We hypothesized that TP r activation contributes to the cardiac phenotype of MD , and that TP r antagonism would improve cardiac fibrosis and function in preclinical models of MD . Methods and Results Three different mouse models of MD (mdx/utrn double knockout, second generation mdx/ mTR double knockout, and delta‐sarcoglycan knockout) were given normal drinking water or water containing 25 mg/kg per day of the TP r antagonist ifetroban, beginning at weaning. After 6 months (10 weeks for mdx/utrn double knockout), mice were evaluated for cardiac and skeletal muscle function before euthanization. There was a 100% survival rate of ifetroban‐treated mice to the predetermined end point, compared with 60%, 43%, and 90% for mdx/utrn double knockout, mdx/mTR double knockout, and delta‐sarcoglycan knockout mice, respectively. TP r antagonism improved cardiac output in mdx/utrn double knockout and mdx/ mTR mice, and normalized fractional shortening, ejection fraction, and other parameters in delta‐sarcoglycan knockout mice. Cardiac fibrosis in delta‐sarcoglycan knockout was reduced with TP r antagonism, which also normalized cardiac expression of claudin‐5 and neuronal nitric oxide synthase proteins and multiple signature genes of Duchenne MD. Conclusions TP r antagonism reduced cardiomyopathy and spontaneous death in mouse models of Duchenne and limb‐girdle MD . Based on these studies, ifetroban and other TP r antagonists could be novel therapeutics for treatment of the cardiac phenotype in patients with MD .

Cellulose nanocrystals (CNCs) are produced by sulfonic acid hydrolysis and used for the formation of Pickering emulsion (PE) with thyme white essential oil (EO). Highly volatile and hydrophobic thyme white is encapsulated in PE by the amphiphilicity of CNCs. Encapsulation of EO in a CNC shell is determined by confocal microscopy with distinct fluorescent labelling. The amount of CNC affects the size distribution of PE, and the emulsion stability is confirmed by rheological property. The antimicrobial activity of the emulsion is evaluated against Escherichia coli and Staphylococcus aureus by minimal inhibitory concentration and minimum bactericidal concentration. The larvicidal activity is also investigated against Aedes albopictus by dispersing the emulsion in water.

To improve the cell suspension of the gelatin-methacrylate(GelMA) bioink, the viscosity of the ink solution was controlled by biocompatible silk fibroin(SF) particles. The viscosity of the GelMA solution increased about 1.4 × 102 folds by the addition of 1 w/v% SF particles. The increase of solution viscosity reduced the displacement of cells and retarded the cell sedimentation significantly. SF-GelMA bioink containing 1 w/v% SF was non-cytotoxic and used for the 3D bioprinting by directly projecting a feature onto the bioink. The cells encapsulated in the structures showed a high level of metabolic activity and demonstrated that SF-GelMA was a biocompatible material.

Myoblast fusion is an indispensable step for skeletal muscle development, postnatal growth, and regeneration. Myeloid differentiation primary response gene 88 (MyD88) is an adaptor protein that mediates Toll-like receptors and interleukin-1 receptor signaling. Here we report a cell-autonomous role of MyD88 in the regulation of myoblast fusion. MyD88 protein levels are increased during in vitro myogenesis and in conditions that promote skeletal muscle growth in vivo. Deletion of MyD88 impairs fusion of myoblasts without affecting their survival, proliferation, or differentiation. MyD88 regulates non-canonical NF-κB and canonical Wnt signaling during myogenesis and promotes skeletal muscle growth and overload-induced myofiber hypertrophy in mice. Ablation of MyD88 reduces myofiber size during muscle regeneration, whereas its overexpression promotes fusion of exogenous myoblasts to injured myofibers. Our study shows that MyD88 modulates myoblast fusion and suggests that augmenting its levels may be a therapeutic approach to improve skeletal muscle formation in degenerative muscle disorders., Myoblast fusion is essential for skeletal muscle development and regeneration. Here the authors show that MyD88 is upregulated during myogenesis and during muscle growth, signals via the NF-κB and Wnt pathways, and that its expression modulates myoblast fusion and myofiber size in mice.

Dental caries are one of the chronic diseases caused by organic acids made from oral microbes. However, there was a lack of knowledge about the oral microbiome of Korean children. The aim of this study was to analyze the metagenome data of the oral microbiome obtained from Korean children and to discover bacteria highly related to dental caries with machine learning models. Saliva and plaque samples from 120 Korean children aged below 12 years were collected. Bacterial composition was identified using Illumina HiSeq sequencing based on the V3–V4 hypervariable region of the 16S rRNA gene. Ten major genera accounted for approximately 70% of the samples on average, including Streptococcus, Neisseria, Corynebacterium, and Fusobacterium. Differential abundant analyses revealed that Scardovia wiggsiae and Leptotrichia wadei were enriched in the caries samples, while Neisseria oralis was abundant in the non-caries samples of children aged below 6 years. The caries and non-caries samples of children aged 6–12 years were enriched in Streptococcus mutans and Corynebacterium durum, respectively. The machine learning models based on these differentially enriched taxa showed accuracies of up to 83%. These results confirmed significant alterations in the oral microbiome according to dental caries and age, and these differences can be used as diagnostic biomarkers.

Among 15 plant methanol extracts, Piper kadsura stem extract (PkSE) showed the strongest larvicidal activity against Aedes albotictus. Larvicidal activities of P. kadsura stem extract were 100 % and 80 % at 0.01 and 0.005 mg/mL concentrations, respectively. Two isobutyl amides, pellitorine and chingchengenamide A, and one neolignan, piperenone, were isolated as active compounds from PkSE. Larvicidal activities of chingchengenamide A, piperenone, and pellitorine were 100 %, 100 %, and 87.5 % at 0.005 mg/mL concentration, respectively, and 100 %, 67.5 %, and 15.0 % at 0.0025 mg/mL. Cellulose nanocrystal (CNC)-stabilized Pickering emulsion of PkSE was developed, and its larvicidal activity was slightly higher than that of pure PkSE. Acute oral and dermal toxicity of PkSE toward rat, Rattus norvegicus, was >2000 mg/kg body weight. Acute contact toxicity of PkSE to honeybee was >100 μg/bee. The no observed effect concentration (NOEC) of PkSE to Oryzias latipes was 0.031 mg/mL.