• Journal of the korean academy of Pediatric Dentistry
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• v.47 no.1
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• pp.36-43
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• 2020

The aim of this study was to assess the occlusal relationships of primary dentition of Korean preschool children in Hwaseong city. Total 444 children of age group between 2 and 5 years were selected. One pediatric dentist took intraoral photos of children. Evaluation and categorization of the primary molar relationships were done by single examiner. Statistical analysis was performed with Pearson chi-squared test. Total 389 samples, which is consisted of 185 boys, 204 girls were satisfied with inclusion criteria. Bilateral mesial step was seen in 61.7%. Bilateral flush terminal plane was seen in 15.4%. When the primary molar relations of the right and left sides were not the same, the combination of the mesial step and flush terminal plane was 14.7%. The present study provides insight into occlusal relationships in the primary dentition of 2 - 5 years old of Korean children in Hwaseong city. Pediatric dentists should understand occlusal relationships of primary dentition for establishment of appropriate treatment strategies and occlusal guidance.

• Journal of the korean academy of Pediatric Dentistry
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• v.28 no.2
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• pp.300-309
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• 2001

The purpose of this study was to investigate the caries prevalence and caries pattern of preschool children in a small city. Six hundred twenty four kindergarten children in Milyang city were examined for their caries experience of individual teeth and surfaces by dmf index. The obtained results were as follows. 1. The rate of children with caries experience(dmft rate) in primary teeth was 74.0% in 3-year-olds, 83.8% in 4-year-olds, and 90.6% in 5-year-olds. The mean number of decayed, missed, and filled primary teeth(dmft index) was 3.47 in 3-year-olds, 5.41 in 4-year-olds, and 6.01 in 5-year-olds. 2. The caries prevalence of children in this study was higher than those of other researches in past and in other cities. 3. The caries-experienced teeth in order in 5-year-olds were as follows : mandibular 2nd primary molar, mandibular 1st primary molar, maxillary 2nd primary molar, maxillary primary central incisor and maxillary 1st primary molar. 4. The pattern of dental caries development was different between the incisors and molars. The prevalent surface of caries was proximal surface in primary incisors, but occlusal surface in primary molars.

• The Journal of the Korean dental association
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• v.50 no.6
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• pp.322-328
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• 2012

Ectopic eruption of the permanent first molar is defined as the eruption of the tooth in an abnormal position or orientation. It may causes distal root resorption and premature exfoliation of the adjacent primary second molar and uncontrolled space loss is followed. Prolonged partial impaction of the permanent molar may also cause undetected caries or abscess formation of the neighbor teeth. The purpose of this paper is to provide a brief review regarding the etiology, classification, and different management techniques for correcting ectopic eruption of permanent first molar.

• Journal of the korean academy of Pediatric Dentistry
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• v.48 no.1
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• pp.12-20
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• 2021

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.

• Journal of the korean academy of Pediatric Dentistry
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• v.51 no.1
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• pp.22-31
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• 2024

The objective of this study was to assess the wear resistance of tooth-colored materials used in crown restoration for primary molars with a chewing simulator. In this study, four groups-three experimental groups and one control group-were included. They consisted of three-dimensional (3D) printed resin crowns (NextDent and Graphy), milled nano-hybrid ceramic crowns (MAZIC Duro), and prefabricated zirconia crowns (NuSmile). Twelve mandibular second molar specimens were prepared from each group. In the wear experiment, 6.0 × 10⁵ cycles were conducted with a force of 50 N, and a 6 mm-diameter steatite ball was used as an antagonist. The amount of wear was calculated by comparing the scan files before and after the chewing simulation using 3D metrology software, and the worn cross-section was confirmed by scanning electron microscopy (SEM). The resin and ceramic groups did not exhibit any statistically significant differences. However, compared to other crown groups, the zirconia crown group demonstrated notably reduced levels of wear (p < 0.05). In SEM images, layers and cracks were observed in the 3D-printed resin crown groups, which differed from those in the other groups.

• Journal of the korean academy of Pediatric Dentistry
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• v.37 no.4
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• pp.519-525
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• 2010

Ectopic eruption means the eruption of the tooth in an abnormal position due to multiple factors, which found most frequently in maxillary fist permanent molars, mandibular lateral incisors and maxillary permanent canines. Ectopic eruption of the maxillary first permanent molar occurs when the molar erupts with a more mesial angulation than normal, and locks itself in an atypical resorption on the distobuccal root of the second primary molar. The maxillary first permanent molar plays important roles for mastication and occlusion, so ectopically erupted maxillary first permanent molars should be relocated into proper position. Treatment options are separation by insertion of the brass wire or elastic rings, preparation of distal aspect of the maxillary second primary molar, using fixed or removable appliance with finger spring, and placement of space maintainer or space regainer after extraction of the maxillary second primary molar. We report three cases treated of ectopically erupted maxillary first permanent molar by re-setting of stainless steel crowns, placement of brass wire and using active plate. We could find out distal movement of maxillary first permanent molars into proper position and normal occlusion.

• Journal of Dental Anesthesia and Pain Medicine
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• v.22 no.5
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• pp.387-394
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• 2022

Background: Dental pain management is an important aspect of patient management in pediatric dentistry. Articaine is considered the most successful anesthetic agent for infiltration anesthesia. Buffered articaine has been observed to have faster onset and longer duration of action with less pain on injection. The aim of this study was to evaluate and compare pain on injection, onset of action, and pain during extraction using buffered (using Sodium bicarbonate (NaHCO₃)) and non-buffered 4% articaine (with 1:100000 adrenaline) infiltrations for primary maxillary molar extractions in 4-10-year-old children. Methods: Seventy children who required extraction of maxillary primary molars were enrolled in this triple-blind randomized study. Children undergoing extraction were randomly divided into two groups, with 35 in each group. The study group was the buffered articaine group; the control group was the non-buffered articaine group. Buccal and palatal infiltrations were administered with either buffered or non-buffered articaine. Subjective evaluation was done for pain on injection, pain during extraction using Wong-Baker Faces Pain Rating Scale (WBFPR) and onset of anesthesia in seconds. Pain on injection, pain during extraction were objectively evaluated using Sound Eye Motor (SEM) scale and onset of anesthesia was also evaluated objectively by pricking with sharp dental probe. Results: The outcome was, significantly less pain on injection and significantly faster onset of anesthesia with significantly less pain during extraction for both subjective and objective evaluations in the buffered articaine group. Subgroup analysis was also performed and it showed variable results, with only significant difference for WBFPR scores in age subgroup 4-7 years for palatal infiltration. Conclusion: Less pain on injection, faster onset of anesthesia, and less pain during extraction were observed when buffered articaine was used for maxillary primary molar extraction.

• Journal of the korean academy of Pediatric Dentistry
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• v.37 no.2
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• pp.179-185
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• 2010

Molar Incisor Hypomineralization(MIH) have recently gained intensive research interests and various clinical trials. Most prevalence, etiology, treatment studies in MIH were carried out in the European countries, and data from the Korean were seldom. This study aimed to investigate the prevalence of MIH and the status of dental caries and treatment on the first permanent molars in primary school children. For this study, 1,344 primary school students in Busan and Ulsan cities were examined directly the permanent incisors and first molars. The results of the survey were as follows: 81 MIH cases were identified among 1,344 cases. The prevalence of MIH in this group of children was 6.0%. Children with MIH showed a significantly higher DMFT value for permanent teeth than children without MIH. The mean number of decayed, missed, and filled in 1st permanent molars(DMFT index) was 1.17. The rate of children with restoration on 1st permanent molar was 13.6% and the sequence of restoration materials was as follows : composite resin, amalgam, gold inlay.

• Journal of the korean academy of Pediatric Dentistry
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• v.47 no.1
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• pp.25-35
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• 2020

The purpose of this study is to evaluate the morphological characteristics of the roots and roots canals of primary molar teeth using Cone-Beam Computed Tomography (CBCT). A total of 68 CBCT images of children aged 4 - 5 years was used for this study. A total of 160 molar teeth were analyzed. Various parameters such as the number of roots and canals, length of root and root canal, and the angulation and shape of the roots were analyzed. All maxillary primary molars had 3 roots. The presence of 2 root canals in 1 root was only observed in the mesiobuccal root of maxillary primary second molars. Most mandibular primary molars had 2 roots, and most mesial roots had 2 root canals. Concerning the length of the roots, the palatal root of the maxillary primary molar was found to be longest whereas the distobuccal root was shortest. In mandibular primary molars, the mesial root was longer than the distal root. In maxillary primary molars, the palatal root had the greatest angulation whereas the distal root has the greatest in mandibular molars. The root and root canals of maxillary primary molars were more curved in shape whereas mandibular primary molars were straight.

• Journal of the korean academy of Pediatric Dentistry
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• v.26 no.2
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• pp.207-217
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• 1999

The purpose of this study was to compare the retentive forces of various types of clasps for removable orthodontic appliances for primary and mixed dentition. Seven metal models of a single tooth and two teeth were made, including maxillary left primary canine, first primary molar, second primary molar and first molar. Retentive forces of Adams clasp, circumferential clasp(C clasp), Jackson clasp, Duyzing clasp, arrowhead clasp, ball clasp, eyelet clasp, and triangular clasp were measured by Universal Testing Machine(Zwick Z020, Germany). The obtained results were as follows. 1. Jackson clasp and Adams clasp showed the highest retentive force among single tooth clasps. 2. C clasp showed the lowest retentive force, and there was no statistically significant difference in retentive force between mesial end C clasp and distal end C clasp. 3. Eyelet clasp showed the highest, and ball clasp showed the lowest retentive farce among clasps for interdental undercut. 4. Triangular clasp showed higher retentive force than ball clasp.