• Journal of the korean academy of Pediatric Dentistry
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• v.35 no.4
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• pp.731-736
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• 2008

Odontogenic keratocyst is classified as a developmental odontogenic cyst and is believed to arise from cell rests of the dental lamina. It accounts for 3% to 11% of all jaw cysts and they occur twice as often in the mandible as in the maxilla. Histologically, the cysts are lined by stratified, keratinizing, squamous epithelium. Daugther cysts or microcysts are often observed microscopically. The recurrence rate has been reported variously, but is known by its high recurrence rate. These lesions are more common in males than in females, occur over a wide age range and are typically diagnosed during the 2nd and 3rd decade. The diagnosis depends on the cyst’s microscopic features and is independent of its location and radiographic appearances. This cyst is a radiolucent lesion that is often multiloculated, has a smooth or scalloped border. The cyst is characteristically located in the body and ramus of the mandible, and often occurs in conjunction with an impacted tooth. This case report describes an odontogenic keratocyst on the lower right molar area of an 8-year-old girl. The cyst was removed under the general anaesthesia, and is being checked regularly for any recurrences.

• Journal of the korean academy of Pediatric Dentistry
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• v.33 no.4
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• pp.693-698
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• 2006

In Class I cavity, the highest C-factor could be obtained and it means the highest polymerization shrinkage stress. In this study, high C-factor model was designed. The pulpose of present study was to determine differences of Microtensile bond strength (MTBS) of class I cavity pulpal and axial wall specimens in primary molar. Twenty clean mandibular 2nd primary molars were randomly divided into two groups Different composite Resins (Filtek Z250, 3M ESPE & Filtek Supreme, 3M ESPE) were bulk filled and photo cured. Axial wall specimens and pulpal specimens were prepared at the same teeth, All specimens were divided into 4 groups and MTBS were evaluated. Group ZP : Filtek Z250-Pulpal wall Group ZA : Filtek Z250-Axial wall Group SP : Filtek Supreme - Pulpal wall Group SA : Filtek Supreme - Axial wall The results were as follows: 1. Mean MTBS of ZP & ZA and SP & SA were significantly different(p<.001). 2. There was no significant difference between MTBS of ZP & SP and ZA & SA.

• Journal of the korean academy of Pediatric Dentistry
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• v.36 no.3
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• pp.325-336
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• 2009

The purpose of this study was to investigate the eruption pattern of the mandibular first molar in sagittal, frontal and horizontal views using the cone beam CT scanning. CT images were obtained from healthy 83 children (42 boys, 41 girls) between 3 to 10 years of age with a normal dentition according to Nolla stage. 1. In the frontal and horizontal view, the intermolar width decreased continuously with stage and slightly increased at the last stage. 2. In the sagittal and frontal view, eruption distances from occlusal plane were observed the largest change between stage 5 and 7. 3. In the horizontal and sagittal view, mandibular first molar from distal surface of primary second molar moved distally between stage 4 and 6. 4. In the sagittal view, angle from occlusal plane to mesio-distal axis increased between stage 4 and 8. 5. In the frontal view, angle from occlusal plane to bucco-lingual axis increased continuously during all stage. 6. In the horizontal view, angle from midsagittal plane to long axis increased between stage 5 and 8.

• Journal of the korean academy of Pediatric Dentistry
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• v.50 no.1
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• pp.113-120
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• 2023

Restoring composite resins with the optimal shades for all primary teeth is a great challenge for pediatric dentists. A newly developed single-shade composite resin can exhibit a color similar to that of the surrounding tooth structure based on the structural color phenomenon. This study aims to evaluate the color adjustment potential (CAP) of a single-shade composite resin compared to conventional multi-shade composite resins in primary teeth. A single-shade composite resin and two conventional multi-shade composite resins were included in this study. Two types of specimens, a single specimen and a dual specimen, were evaluated. For single specimens, duplications of the primary second molar denture teeth were made using experimental composite resins. For dual specimens, cavities were prepared on the buccal surfaces of extracted primary second molars and restored with experimental composite resins. The L^*, a^*, and b^* values were measured using a colorimeter for the extracted teeth and specimens. The mean ΔE_ab^* values for single and dual specimens and CAP were calculated. Bonferroni post-hoc analysis was performed to confirm the statistical significance between the ΔE_ab^* and CAP values of the experimental resins. Among the single specimens, the single-shade composite resin showed significantly higher ΔE_Single compared to other composite resins (p < 0.0167). There was no significant difference between ΔE_Dual for all experimental resins. The single-shade composite resin showed highest CAP compared to other multi-shade composite resins. A single-shade composite resin exhibited the most prominent color adaptability compared to other conventional multi-shade composite resins for primary second molars. A single-shade composite resin can simplify shade matching and provide esthetic outcomes for the restoration of primary second molars.

• Journal of the korean academy of Pediatric Dentistry
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• v.36 no.2
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• pp.275-280
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• 2009

Radicular cyst is a true epithelium lined cyst formed when epithelium at the apex of a nonvital tooth is stimulated by inflammation. It is the most common type of cyst in the oral cavity, but its frequency is low in the primary dentition. Treatment of large-sized cyst aims at conservation of adjacent structure and allowance of proper eruption of the successive permanent teeth in the primary dentition. Considering these two aspects, marsupialization or enucleation following decompression is recommended as a treatment means for large-sized radicular cyst. In this case, 8-year old boy visited the pediatric dentistry department. Yonsei University Dental Hospital, with the chief complaint of pain on the lower right area. Clinical and radiographic examinations revealed periapical radiolucent lesion on #84, which had previous pulp treatment and restorated with the stainless steel crown. Dislocation of its successive tooth, #44, was also observed. #84 was extracted and sent for biopsy. Through histologic examination, it was diagnosed as radicular cyst. Following its extraction, removable space maintainer was delivered, which was also used as a decompressor. During periodic check-up for next 22 months, favorable healing of the lesion and eruption of the successive tooth were observed.

• Journal of the korean academy of Pediatric Dentistry
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• v.44 no.3
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• pp.370-377
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• 2017

Molar-incisor malformation (MIM) is a recently described dental anomaly characterized by root malformation in permanent first molars accompanied sometimes by abnormal root forms in primary second molars or enamel defects in maxillary central incisors. This report presents three cases of MIM along with a review of previous studies. Three patients exhibited abnormal root forms in the permanent first molars, with varying degrees of deformation. Two of the patients experienced medical events at birth. One of the patients was a monozygotic twin, whose twin sister exhibited normal dentition without any significant abnormalities. The present report also reviews recently reported cases of MIM in literature. In the management of MIM-associated clinical issues, consideration of microscopic features and accompanying characteristics might facilitate early diagnosis and comprehensive treatment planning.

• Journal of the korean academy of Pediatric Dentistry
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• v.28 no.3
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• pp.369-373
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• 2001

The congenital missing of mandibular second premolars is among the common dental anomaly in children. When a second premolar is diagnosed as congenitally missed, we should consider many factors influencing the treatment plan such as patient's age, states of roots of 2nd primary molar, degree of crowding, skeletal growth pattern, facial profile, procumbency of the incisor and lower facial height, etc. The mineralization of the second premolars begins in the majority of cases at the age of $2\sim2\frac{1}{2}$ years, but this period varies more widely than those for other permanent teeth. Also, mandibular second premolars show the greatest variations in differentiation and calcification. For this reason, aplasia of this group of teeth cannot be diagnosed at early age and with the same degree of certainty. From the clinical studies with 2 cases and some literature review on late development of second premolars, it could be summarized as follows : 1. The 2 cases showed marked delay in the development of mandibular second premolars. 2. After the crypt formation, the speed of calcification seemed nearly normal, suggesting that the delay was due to differentiation rather than calcification. 3. When one is encountered with similar conditions, it would be desirable to consider the possibility of delayed tooth development.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.33 no.6
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• pp.669-676
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• 2007

Orbital infection or inflammation is a rare but serious complication of an odontogenic infection. Odontogenic infection can spread to the orbit by one or more of several paths. Such extension is potentially dangerous and can lead to loss of vision or worse. 5-cases of orbital infection and inflammation secondary to infection from upper or lower molar teeth, which extended to the subperiosteal or the retrobulbar region of the orbit, are presented in this report. The infections spreaded to the infratemporal and temporal fossa or the ethmoidal labyrinth, and then to the orbit via the inferior orbital fissure or the lamina papyracea. The clinical presentation, differential diagnosis, route of spread, value of serial CT scanning, treatment and possible complications are reviewed.

• Journal of the korean academy of Pediatric Dentistry
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• v.45 no.3
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• pp.299-306
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• 2018

The aim of this study was to evaluate the effect of etching time and bonding agents on bond strength of sealant applied to the occlusal surface of primary molars. Forty non-carious exfoliated human primary molars were included in the study. The teeth were randomly divided into 4 groups for measurement. For group I, no acid etching treatment was used. For group II, III, and IV, acid etching gels were applied on the occlusal surface for 15, 30, and 60 seconds, respectively. Each group was divided into 2 subgroups; one group was treated with bonding agents on the enamel while the other was not. Microtensile bond strength was evaluated using a universal testing machine. There were no statistically significant differences in bond strength with varying duration of etching among groups. The results revealed that the use of bonding agents prior to application of fissure sealant increased the bond strength(p < 0.05). It could be concluded that etching time greater than 15 seconds does not significantly enhance the bond strength, but the use of bonding agents as an intermediate layer between the primary molar and fissure sealant would be beneficial in increasing the bond strength.

• Journal of the korean academy of Pediatric Dentistry
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• v.42 no.2
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• pp.172-179
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• 2015

The developmental mechanism of root formation is a complex process. Hereditary and environmental factors may affect the morphology of the developing root. A total of 12 cases was presented with permanent first molars with abberant root morphology. Clinically, these teeth appeared as a normal crown. However, radiographically, the root was slender, twisted and characterized by irregular lengths. In addition, root trunk length was shorter and pulp chamber was obliterated. In these cases, periapical radiolucency and loss of lamina dura were often observed. In 6 cases, an abnormal root of the primary second molars were also present, as well as root malformation of permanent first molars. In 3 cases, permanent central incisors also had a dysmorphic crown. These cases almost all had medical history, such as premature birth, brain infection or congenital heart disease in infants. The present paper describes cases of permanent first molars with an abnormal root that are rarely reported in literature. This case may intensify the variation in the permanent first molar and is intended to reinforce the clinician's awareness of rare morphology of the roots.