In Vitro Study on the Bond Strength Between 3D-Printed Resin and Resin Cement for Pediatric Crown Restoration / 대한소아치과학회지

A 3D-printed resin crown is a novel option for esthetic crown restoration for primary teeth, which are typically bonded with resin cement. The purpose of this study was to evaluate the bonding ability of a 3D printing resin and compare it with other indirect resin materials for crown fabrication. The shear bond strengths of two 3D printing resin materials, Graphy (GP) and NextDent (NXT), and two indirect resin materials, VIPI Block (VIPI) and MAZIC Duro (MZ), were compared in the study. For all materials, the shear bond strength at the interface between the surface of the resin material and resin cement was measured. The mean shear bond strength values of GP, NXT, MZ, and VIPI were 23.29 ± 3.88, 26.14 ± 4.67, 25.41 ± 4.03, and 18.79 ± 4.26 MPa, respectively. There was no significant difference among the SBSs of GP, NXT and MZ except for VIPI. The result of this study indicates that the 3D printing resin meets the essential requirement for clinical use by showing clinically adequate bond strength.

Impact of Coronavirus Disease 2019 on Dental Service Utilization of Korean Children and Adolescents / 대한소아치과학회지

This study aimed to investigate the frequency of dental visits after coronavirus disease 2019 (COVID-19) in children and adolescents in comparison to that of adults. The data on the number of dental visits on the basis of different classification and treatment codes for all the age groups were provided by the Health Insurance Review and Assessment Service from January 2017 to December 2020. To reduce the impact of the population change, dental visits per 1000 people was used. After the start of the pandemic, dental visits per 1000 people decreased in all age groups when analyzed for the diseases of pulp and periapical tissues classification code and dental visits per 1000 people decreased over 5 years age groups when analyzed for the pulp treatment code. Regarding the restorative treatment code, visits in the 0 - 19 years age group decreased after the pandemic. Based on the comparison of the number of confirmed COVID-19 cases to that of monthly dental visits by treatment codes, the change rate of pulp and restorative treatments gradually decreased after the waves of the pandemic in February and August 2020 in Korea. Furthermore, dental visits per 1000 people for gingivitis and periodontal disease classification code increased after the pandemic in all age groups. The rate of decrease in dental visits per 1000 people for restorative treatments in children and adolescents was higher than that in adults. The rate of decrease in the number of dental visits for multi-visit pulp treatments showed a rapid decrease as compared to that of 1-visit pulp treatments after the pandemic. This study identified changes in the number of dental visits of children and adolescents after COVID-19 transmission in comparison to that observed in adults.

National Oral Health Screening for Infants and Children: A Survey on its Perception, Requirements and Accuracy of Parents and Dentists / 대한소아치과학회지

This study aimed to investigate parents’ and dentists’ perceptions of the national oral health screening for infants and children (OHS), and evaluate the dentists’ accuracy of analyzing the results of OHS. A questionnaire survey was conducted, face-to-face or online, for 90 parents of children who received OHS in the Department of Pediatric Dentistry at Yonsei University Dental Hospital and 100 dentists working at local clinic or university dental hospital from May to October 2021. Most parents and dentists were aware of the importance of OHS, and approximately 96.7% of parents were satisfied with OHS. The requirements of parents and dentists about OHS were different. The reasons for having difficulties in explaining parents after OHS and the opinions on appropriate period and number of OHS were disagreed between pediatric dentists and general dentists. Regardless of dentists’ major, work experience, elapsed period after taking online education program, the accuracy of the examination result was low. In this study, various opinions of parents and dentists on OHS were collected. Efforts should be made to enhance the oral health of infants and children by considering the requirements of parents and dentists and improving the accuracy of examination results.

Effects of Essential Oil Containing Mouth Rinse in Children with Black Staining : Two Case Reports / 대한소아치과학회지

Black staining of the teeth in children and adolescents does not cause pain or serious illness, but it can be socially debilitating for esthetic reasons. Black staining is easily removed through periodic professional mechanical tooth cleaning and ultrasonic scaling, but it can easily recur within few months. Using essential oil-containing mouth rinses diluted at 50% twice per day could prevent the black staining from returning after it is removed, reducing the need for mechanical treatments and improving esthetics.

Assessment of Dental Noise Environment of a Pediatric Dentist / 대한소아치과학회지

The noise is defined as unwanted sound that causes discomfort and physical changes. This study was conducted to evaluate intensity of noise in the pediatric dental clinic and to investigate noise environment of a pediatric dentist. Human ear shaped microphone and mobile noise level meter were used for recording noise and calculating intensity of noise.By recording according to the method specified by Korea Occupational Safety and Health Agency (KOSHA) of Korea Ministry of labor and employment, the following results were obtained. For 16 experimental days, 8 hour time weighted average (8hr-TWA) was 49.33 dBA (A-weighted deci-Bell) on daily average with maximum 58.54 dBA and minimum 33.97 dBA. And Dose was 0.49% on daily average with maximum 1.28%, minimum 0.04%. These values are less than criteria of KOSHA standard (85 dBA, 100%). Comparing the highest noise level for each patient, pulp therapy group and Frankel grade I group were the highest.The intensity of dental noise of pediatric dental clinic didn’t meet standard of KOSHA. It is necessary to re-evaluate noise environment by establishing new standards considering environment of pediatric dental clinic.

Accuracy of Automatic Cephalometric Analysis Programs on Lateral Cephalograms ofPreadolescent Children / 대한소아치과학회지

The aim of this study was to evaluate the accuracy of 3 different automatic landmark identification programs on lateral cephalgrams and the clinical acceptability in pediatric dentistry.Sixty digital cephalometric radiographs of 7 to 12 years old healthy children were randomly selected. Fourteen landmarks were chosen for assessment and the mean of 3 measurements of each landmark by a single examiner was defined as the baseline landmarks. The mean difference between an automatically identified landmark and the baseline landmark was measured for each landmark on each image.The total mean difference of 3 automatic programs compared to the baseline landmarks were 2.53 ± 1.63 mm. Errors among 3 programs were not significantly different for 12 of 14 landmarks except Orbitale and Gonion. The automatic landmark identification programs showed significant higher mean detection errors than the manual method. The programs couldn’t be used as the 1st tool to replace human examiners. But considering short consuming time, these results indicate that all 3 programs have sufficient validity to be used in pediatric dental clinic.

Correlation between Dental and Skeletal Maturity in Korean Children / 대한소아치과학회지

The aim of this study was to investigate the relationships between the stages of calcification of various teeth and skeletal maturity stages among Korean subjects. The samples were derived from hand-wrist, panoramic radiographs, and lateral cephalograms of 743 subjects (359 males and 384 females) with ages ranging from 6 to 14 years. Calcification of seven permanent mandibular teeth on the left side were rated according to the system of Demirjian. To evaluate the stage of skeletal maturation, hand-wrist radiographs were analyzed by skeletal maturity indicators (SMI) system of Fishman and lateral cephalograms by cervical vertebral maturation (CVM) method of Baccetti. Statistically significant relationships were found between dental calcification and skeletal maturity stages according to Spearman rank-order correlation coefficients (r = 0.40-0.84, p < 0.001). The second molar showed the highest correlation and central incisor showed the lowest correlation for female and male subjects. For both sexes, canine stage G and second molar stage F were related to SMI 6 and CS 3. Because of the high correlation coefficients, this study suggests that tooth calcification stages from panoramic radiographs might be clinically useful as a maturity indicator of the pubertal growth period in Korean patients.

Analysis of the Prevalence of Taurodont Deciduous Molars in Children / 대한소아치과학회지

Taurodontism is an anomaly characterized by a long and broad pulpal cavity and consumed apical location of the furcation area. This study aimed to determine the prevalence of taurodontism in deciduous molars based on digital panoramic radiographs of children. The study was performed on a sample of panoramic radiographs taken from 2,473 Korean children who visited the department of pediatric dentistry, Yonsei University Dental Hospital between Nov. 2005 and Mar. 2018. Taurodontism was mainly categorized by Daito’s method. Using panoramic radiographs, taurodontism was also categorized into mesotaurodontism, hypotaurodontism, and hypertaurodontism. Mesotaurodontism was the most prevalent type. A total of 2,473 panoramic radiographs were evaluated. The prevalence of taurodontism was 5.7% in general, 51.5% in the left quadrant, 48.5% in the right quadrant, 6.3% in the maxilla, and 93.7% in the mandible. The distribution of taurodontism stratified by gender showed a higher prevalence in males. This is a comprehensive study on the prevalence of taurodontism in children using the largest sample size to date.

A Study on Visual Exploration of Children and Adolescents during Dental Treatment / 대한소아치과학회지

The aim of this study is to investigate visual exploration of children and adolescents during dental treatment by examining time ratio of eye opening in various age groups.This study reviewed 5 - 15 year-old patients who visited the department of pediatric dentistry of Yonsei University Dental Hospital from March to October 2018. Restorative treatment or sealant application was done by one pediatric dentist. A trained observer used 2 stopwatches to measure total treatment time and time of open eye. Average ratios of eye opening were calculated and compared.60 patients were investigated, with 15 patients in each age group. Average ratio of eye opening increased as age decreased (p This study indicated that children have higher rates of eye opening during dental treatment than adolescents.

Effect of Noise Cancelling Devices on Dental Handpieces Using Ear Model / 대한소아치과학회지

This study intended to evaluate noise level of dental handpieces and the effects of noise cancelling devices. An ear model was designed to measure the level of the noise delivered to the inner ear during dental handpiece operation. The level of noise was measured in various conditions using the ear model and the portable noise meter. Noise level was measured again after applying of 4 different noise cancelling devices to the model ear.The noise level of dental handpieces was 82.5 - 84.4 dB. When 4 types of noise canceling devices were applied, the noise level reduced to 67.4 - 73.8 dB. All 4 devices had statistically significant effect in reducing the noise of the handpiece.Considering the intensity and exposure time, noise in dental clinics can cause hearing damage to dentists. For protection from the risk of occupational hearing damages, noise canceling devices can be recommended.

Status and Survey of Pulp Treatment by Korean Pediatric Dentists / 대한소아치과학회지

The pulp treatment of primary and immature teeth in the children and adolescents is affected by the environment of the patients, clinical careers and dentists performing the techniques, as well as clinical modalities and pulpal diagnosis. The purpose of this study was to investigate the current status of pulp treatment performed in real clinical practice, as well as the reasons behind the choice of treatment methods. The study was conducted on a total of 153 members of the Korean Academy of Pediatric Dentistry, and statistical data from the Health Insurance Review and Assessment Service (HIRA) from 2010 to 2018 were analyzed ogether. Both the survey results and the statistics from the HIRA showed that 1-visit pulpectomies of primary teeth were most common, and the frequency of the use of the Ni-Ti file was increased in children with primary or mixed-dentition. In the treatment of immature permanent teeth, regenerative endodontic treatment by individual dentists was found to be less frequent than in university hospitals.

Evaluation of Characteristics of the Dental Maturity in Girls with Precocious Puberty / 대한소아치과학회지

Precocious puberty (PP) is defined as the early development of secondary sexual characteristics (before the ages of 8 years in girls and 9 years in boys). The aim of this study is to identify characteristics of the dental maturity in girls with PP that discriminate them from normal healthy girls. This study included 99 girls aged 6 - 8 years with PP and 99 girls without past medical history of same chronological age (control group). The study was performed on 198 panoramic radiographs (99 PP girls, 99 control group girls). Demirjian method was used to evaluate the panoramic radiographs and determine dental maturity. Difference in dental maturity score and tooth formation stages between the two groups were analyzed. The PP group showed significant higher maturity score than control group. Among mandibular teeth, mandibular 2nd premolar and 2nd molar were significantly more mature in the PP group than control group. Logistic regression analysis showed that mandibular 2nd molar was only significant predictor for PP girls.

Comparative Histologic Study of 3-Root Canal Filling Materials for Dog's Teeth / 대한소아치과학회지

Endodontic treatment of primary molars is a great challenge to the dentists because of their complex morphology. However, there have been limited controlled in vivo studies about filling materials for primary teeth. Hence, the aim of this study is to evaluate and compare histologic responses of different calcium hydroxide canal filling materials that are used in daily clinical practice.Pulpectomies were performed in 132 teeth of the dogs. The root canals were randomly filled with either Vitapex® (n = 44), Metapex® (n = 44), or Metapaste® (n = 44). After 4 or 13 weeks, respectively after operation, the dogs were sacrificed, and teeth were processed for histologic examinations. Inflammatory reaction was evaluated and scored in a blind manner. The Fisher's exact test and Kruskal-Wallis test were used to compare the tested groups.In 4-week-group, all inflammatory responses were in normal range except for fibrosis. In 13-week-group, increased response to various inflammation reaction was shown compared to the 4-week-group. However, there were no statically significant differences between the tested groups in all inflammatory reaction.Overall, there were no significant differences among three materials in responses of apical tissues and all of them showed favorable tissue responses.

Dental complications associated with neonatal intubation in preterm infants

This paper describes the potential oral complications in preterm infants who have undergone orotracheal intubation. Neonatal intubation may have adverse effects on the developing deciduous teeth, oral soft tissues, and even the permanent teeth. However, endotracheal intubation may be essential for the survival of premature infants, owing to incomplete tracheal development. Excessive pressure to the oral tissue must be avoided, in cases where orotracheal intubation is inevitable. Moreover, the potential oral complications must be considered when neonatal intubation is performed for the patient's survival, and subsequent reevaluation and proper oral health care are needed.

Comparison in Demineralization Resistance of Resin Infiltration and 1.23% Acidulated Phosphate Fluoride in Bovine Teeth / 대한소아치과학회지

The aim of this study is to compare the differences of the demineralization resistance of resin infiltration and 1.23% acidulated phosphate fluoride in bovine teeth with artificial caries. We applied 1.23% Acidulated phosphate fluoride (APF) gel and Icon® caries infiltrant on the artificial bovine enamel carious lesion and then demineralized all samples. The depth of demineralization was measured by using Confocal Laser Scanning Microscope (CLSM) and observed the roughness and irregularity of the enamel was observed by Scanning Electron Microscope (SEM).In this experiment with demineralization resistance on smooth artificial carious lesion, less depth of demineralization, roughness, and irregularity of enamel was observed in APF gel and Icon® group than in the control group. There was no significant difference between the depth of demineralization of 1.23% APF gel and Icon® caries infiltrant group. However, resin infiltration is beneficial as less roughness and irregularity was observed on the enamel surface than when 1.23% APF gel is applied.

Role of OD314 During Odontoblast Differentiation / 체질인류학회지

Odontoblasts are responsible for the formation and maintenance of dentin which is a mineralized part in dentin-pulp complex of tooth. OD314 was obtained by subtractive hybridization between odontoblasts and osteoblast/dental papilla cells, and differentiatially expressed in the odontoblasts but not in osteoblasts and dental papilla cells. In this study, to better understand the biological function of new odontoblast-enriched gene, OD314, we examined expression of OD314 in cultured MDPC-23 cells and intracellular localization of OD314 protein. We also evaluate the effect of OD314 over-expression and inactivation on the cells by northern analysis. When MDPC-23 cells are cultured in the differentiation and mineralization medium for 28 days, OD314 mRNA expression was gradually increased from the beginning to day 21 and remained relatively high on day 28. Immunofluorescent staining of cultured MDPC-23 revealed localization of OD314 on the cytoplasm, especially near the nuclear membrane. However, a small amount of fluorescence was also observed in the nucleus. Inactivation of OD314 by RNA interference up-regulated the expression of DSPP, whereas over-expression of OD314 by CMV-OD314 plasmid down-regulated the expression of ON. These results suggest that OD314, a odontoblat-enriched gene, may play important roles in the odontoblast differentiation and dentin mineralization.