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.

Masticatory Performance and the Related Factors in Korean Children and Adolescents / 대한소아치과학회지

This study aimed to evaluate the masticatory performance of Korean children and adolescents and to investigate related factors. Early loss of primary molars, degree of occlusion of first molars, occlusal relationship of first molars, and presence of anterior crossbite were considered. From March 2020 to July 2021, 56 children and adolescents between the ages of 6 and 12 were included. The mixing ability index (MAI) was calculated to evaluate the masticatory efficiency of children and adolescents. The subjects were classified into three groups according to the number of early lost primary molars; normal dentition, 1 - 2 teeth lost, more than 3 teeth lost. The number of participants are 23, 18, and 15, respectively. There was no difference in the MAI values between the normal dentition group and the group has 1 - 2 teeth lost. However, when 3 or more primary molars were lost, the MAI value decreased and a significant difference was observed. This study is the first study to evaluate the masticatory performance of children and adolescents in Korea, and it will be helpful to pediatric dentists who evaluate the masticatory performance of children and adolescents and strive to improve the masticatory efficiency of children and adolescents in clinical practice.

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.

Correlation of Left Mandibular Third Molar Development and Chronological Age / 대한소아치과학회지

The aim of this study is to evaluate the development of the left mandibular third-molar development with modified Demirjian method and its relation to chronological age.A total of 1653 digital panoramic radiographs of healthy individuals aged between 7 and 23 years who visited Yonsei University Dental hospital were selected. The developmental status of the left mandibular third molars was assessed using dental maturity scoring proposed by Demirjian et al. The mean age of the first appearance of mineralization, complete crown formation, and complete root formation were around 9, 14, 21 years respectively. Statistically significant differences between males and females in the development stage of D and G were revealed that crown formation and root length completion were attained earlier in males than in females. There was significant positive relationship between age and third molar development in both sexes, and new formula was presented to estimate age of children and adolescents based on their developmental stages of third molars.In this study, the use of left mandibular third molar as a developmental marker is appropriate, and age estimation can be attained with dental maturity stage.

Assessment of the Caries Detection Ability of Quantitative Light-induced Fluorescence (QLF) in Primary Teeth in vitro / 대한소아치과학회지

The aim of this study was to evaluate QLF (quantitative light-induced fluorescence) technology for the caries detection in primary teeth and validate the relationships between the cavity volume of carious lesions and QLF analysis results. Total 125 tooth surfaces include 53 occlusal surfaces, and 72 proximal surfaces were investigated with the portable QLF device for detection of dental caries in primary molars. Micro-CT radiograph was also performed to classify carious lesions and calculate the cavity volume. QLF showed good accuracy and reliability (sensitivity 0.75 - 0.94, specificity 0.82 - 0.95, and AUROC 0.88 - 0.98) for the caries detection in primary teeth except ΔR average results of proximal caries which showed relatively low values. Statistically significant relationships were found between ΔF average, QS-Index and the cavity volume according to Spearman rank-order correlation coefficients (r = 0.805 - 0.832, p < 0.001). QLF detection method would be a harmless and reliable way for children to diagnose dental caries without the concern about radiation exposure.

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.

Survey on Sedation Training for Pediatric Residents in Training Hospitals / 대한소아치과학회지

The purpose of this study was to investigate current status of sedation training for the residents in pediatric dentistry training institutions and opinions about continuing education after the residency program. Surveys were sent to 18 pediatric dentistry training institutions by e-mail, and the responses were collected and analyzed. Most of the sedation education period for the residents were the 1st-year education (61.1%) and 1 - 3 years of integrated education (55.6%). In terms of an externship, 5 institutions (27.8%) sent their residents to the department of anesthesiology. Second half of the 1st year (50%) was the highest for a resident to use sedation for the first time. The period of supervisor participation varied from not participating at all to whole time throughout the residency program. The sedation training is conducted at all training institutions, but there were variations in the experience that a resident can gain. All training institutions agreed on the necessity of continuing education of the sedation, but there were various opinions regarding time, method, and the period of review course. Overall, this study suggested that continuing education should be consisted of 1 - 2 hours of didactic education every year and clinical skills and simulation training in every 2 - 3 years.

Analysis of Prevalence of Pyramidal Molars in Adolescent / 대한소아치과학회지

A pyramidal molar is which has completely fused roots with a solitary enlarged canal. The purpose of this retrospective study was to assess the prevalence and characteristics of pyramidal molars among adolescent.A total of 1,612 patients’ panoramic radiographs were screened. A total of 12,896 first and second molars were evaluated. The relative incidence and the correlations regarding the location of pyramidal molar (maxillary versus mandibular) and gender were analyzed using the chi-square test.The overall incidence of patients with pyramidal molars was 1.49%. 24 patients were found to have a pyramidal molar and it was more prevalent in women (18 women and 6 men). The prevalence of pyramidal molars from all first and second molars examined was 0.31%. 88 percent of pyramidal molars occurred in maxilla. All pyramidal molars were second molar.Pyramidal molar has a relatively poor periodontal prognosis compared with common multi-rooted teeth and it is important to understand the structural characteristics of root canal during pulp treatment. Clinicians should be able to understand the anatomical properties of pyramidal molar and apply it to treatment and prognostic evaluation.

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.

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.

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.

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.

Analysis of Treatment Period on the Intraoral Removable Appliance Utilizing Vertical Facial Growth on Class III Malocclusion / 대한소아치과학회지

Vertical facial growth triggers the rotation of mandible to move the chin point to the downward and backward direction, which showed remarkably effective result making the less prominent chin. Recently, the intraoral removable appliance utilizing class III elastic demonstrated the vertical growth trigger mechanism. The treatment change was very fast and wearing was quite easy, compared to extraoral appliances.The purpose of this study was to verify the duration of the treatment on class III malocclusion using intraoral removable appliances, which designed to accelerate vertical facial growth.56 patients were selected with the complaint of the protruded mandible and class III malocclusion (overjet : −3 – 0 mm, overbite : 0 – 4 mm). Information like; age at start, duration of the treatment events, type of the treatment, overjet, overbite etc. was collected and calculated.The average age of the patients delivering the initial brace was 8.75 ± 1.10 year. Most of the anterior crossbite was resolved within 6 months. The total treatment period was 21.79 ± 10.73 months with the additional procedures like the alignment of anterior teeth and torque control using additional removable and fixed orthodontic appliances. The correlation study showed that patient's cooperation (p = 0.000) and the use of fixed appliance (p = 0.032) were significantly influenced on treatment duration.

Dental Consultations and Treatment Pattern of Pediatric Inpatient in Severance Hospital / 대한소아치과학회지

The purpose of this study was to analyze the dental consultation of pediatric inpatients to the department of pediatric dentistry in Yonsei University Severance Hospital, and to investigate the change in patterns. In 2017, 268 pediatric patients (384 cases) admitted to the Severance Hospital were referred to the department of pediatric dentistry. The mean age was 6.6 years, and most of the patients were referred from the Department of Pediatric Hematology Oncology and Rehabilitation Medicine. The chief complaints were as follows: oral examination (31%), dental caries (20%), oral pain (10%), tooth mobility (10%), pre-operative evaluation (9%) and others (20%). 41% of the patients received only oral examination without treatment. Dental caries were the most frequent dental diagnosis of the patients. 28% (111 cases) of patients received operative treatments, 22 cases were treated under general anesthesia. Oral health is closely related to systemic diseases, especially for hospitalized patients. Dental consultations should be encouraged for prevention and early appropriate treatments. For this purpose, it is necessary to establish a referral system and perform dental treatment under general anesthesia.

Tooth Agenesis and Delay in Patients with Agenesis of Mandibular Second Premolars / 대한소아치과학회지

Tooth agenesis is a common human dental anomaly and the agenesis of mandibular second premolars has been proven to be the most frequently observed. The aim of this study is to investigate tooth agenesis and delayed tooth development in patients with agenesis of mandibular second premolars.This study reviewed 9 to 15 year-old patients with agenesis of mandibular second premolars who visited the department of pediatric dentistry of Yonsei University Dental Hospital and took panoramic radiographs from January 2014 to December 2016. On panoramic radiographs, agenesis of teeth was observed and developmental delay of teeth was evaluated by the Nolla method. Among 125 patients with agenesis of mandibular second premolars, 58 patients (46.4%) showed agenesis of other teeth and 38 patients (30.4%) showed delayed tooth development. In this study, patients with agenesis of mandibular second premolars were more likely to have tooth agenesis or delayed eruption of other teeth.

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.