• Journal of the korean academy of Pediatric Dentistry
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• v.34 no.3
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• pp.481-489
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• 2007

Maxillary canine impaction is a frequently encountered clinical problem, and it may cause the resorption of adjacent tooth or cystic change. Treatment plan for maxillary canine impaction should be decided among extraction, orthodontic traction and autotransplantation according to several factors such as direction and position of unerupted tooth, degree of developing root apex, eruption space, exsitance of supernumerary tooth, odontoma, or cyst. Autotransplantation is a valuable alternative to extraction of impacted teeth, where surgical exposure and subsequent orthodontic realignment are difficult or impossible due to unfavorable impaction position. And its prognosis is dependent on a number of factors such as preservation of periodontal ligament, degree of root development, surgical technique, patient's age, endodontic treatment, time and type of splinting and storage medium, etc. The patients in these cases visited our dental clinic in the late permanent dentition with the chief complaint of unerupted maxillary canines. And it was thought that the spontaneous eruption guidance or orthodontic traction and alignment were difficult because of its unfavorable impacted position. Therefore, autotransplantaion and endodontic treatment were done and have been checked periodically until now.

• Journal of Periodontal and Implant Science
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• v.34 no.2
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• pp.269-279
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• 2004

백악질 세포의 분리 및 배양방법을 확립하고, 이를 이용하여 백악질 세포의 형질특성을 알아보고자 하였다. 교정목적으로 발거된 소구치를 이용하여, 치은섬유아세포, 치주인대 세포 및 백악질 유래세포를 분리, 배양하였다. 백악질 유래 세포 배양시에는 백악질을 절제한 후 Collagenase P를 이용하여 백악질 유래 세포 외의 다른 세포의 개제를 배제하였고, 기질을 분해하여 세포의 분리 및 배양이 용이하도록 하였다. 분리 및 배양시기의 세포의 형태를 광화현미정을 이용하여 관찰하였다. 조골세포의 특성을 가지는 SaOs-2 세포를 대조군으로 이용하여 분리 및 배양된 세포군들을 동일한 조건으로 배양하였다. 3일 및 7일째에 세포증식도를 측정하였고 7일째에 ALPase 효소 활성도를 측정하였다. 각 세포의 형질 특성을 알아보기 위해 RT-PCR을 실시하여 조골세포 분화 표식자와 연관된 osteopontin(OPN), Alkaline phosphatase(ALP), type I collagen(COL-I), Bone sialoprotein(BSP), BMP-2 및 osteocalcin(OC)의 발현을 비교 관찰하였다. 백악질 유래 세포의 분리 및 배양을 시도한 5명의 치아 중에서 3명의 치아에서 세포군을 배양해 낼 수 있었다. 배양한 백악질 유래 세포는 섬유아세포와 유사한 형태와 증식을 보였다. ALPase 효소 활성도 검사 결과 백악질 유래 세포는 SaOs-2 세포보다 낮은 활성도를 나타내었으며, 배양된 세포의 RT-PCR 결과 백악질 유래 세포군에서는 ALPase의 발현이 나타나지 않았고, 다른 조골세포 표식자의 발현도 낮게 나타났다. 이는 백악질 유래 세포가 조골세포 및 다른 대조군의 세포와는 다른 형질 특성을 가지고 있다는 것을 시사한다. 이상의 관찰결과로 사람의 백악질 유래 세포롤 백악질의 절제 및 효소처리 방법으로 효과적인 분리 및 배양이 가능하며, 이는 향후 백악질 세포의 형질 특성 및 백악질 형성의 분자적 기전을 파악하는 중요한 연구자료로 활용 될 수 있을 것으로 사료된다.

• Journal of the korean academy of Pediatric Dentistry
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• v.38 no.3
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• pp.303-308
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• 2011

Tooth impaction refers to situations in which the eruption is inhibited by some physical barriers in eruptive path and the tooth remains unerupted beyond the normal time of eruption. The etiology of impacted tooth is controversial, but ankylosis has been suggested probably as a leading role. Impacted primary molars may cause several problems such as space loss, tipping of adjacent teeth, supra-eruption of the antagonists, dislocation of succeeding premolar, cystic change and infection. As one of conventional treatments of impacted primary molars, early tooth extraction or surgical extraction following space regaining when there is space loss has been suggested. However, when they are in normal formation and not ankylosed, orthodontic traction following surgical exposure can be the choice of treatment. In this case, a 3-year-old boy was referred to the department of pediatric dentistry for the unerupted mandibular right second primary molar. After surgical removal of gingiva on the occlusal surface, orthodontic traction was performed. After treatment, we could get normal alignment of primary teeth and the opportunity for normal development of permanent teeth.

• Journal of the korean academy of Pediatric Dentistry
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• v.33 no.3
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• pp.534-547
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• 2006

Ectopic eruption and impaction of canines is a frequently encountered clinical problems. The incidence of impaction ranges between 1-3%. The cause of canine impaction can be the result of localized factors or can be a polygenic multifactorial inheritance and associated with other dental anomalies. The general dentist and pediatric dentist should know how to properly diagnose and manage potential disturbances in the eruption of maxillary canine. Diagnosis of impacted canine at age 8-10 years can significantly reduce serious ramifications, including surgical exposure and orthodontic traction as well as root resorption of the lateral incisors. Extraction of primary canine would be one of the method to prevent the impaction. The surgical procedure should be designed to minimize the destruction of periodontal tissue of impacted canine. Closed eruption technique is thought to be optimal method of surgical exposure compared with other methods. An overview of the incidence, sequela as well as the surgical periodontal, and orthodontic consideration in the management of impacted canine was presented.

• Journal of the korean academy of Pediatric Dentistry
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• v.36 no.4
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• pp.619-624
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• 2009

Pyknodysostosis(PKND) is a rare sclerosing bone disorder that has an autosomal recessive trait, also known as Toulouse-Lautrec syndrome. Deficiency of the cathepsin enzyme K in the osteoclasts of PKND patients results in continuous endosteal bone deposits without osteoclastic resorption or remodeling. This causes a generalized increase in sclerosis and fragility of bones. Osteomyelitis in the mandible and recurrent fracture of the long bones are characteristic complicatons of PKND. The patients present typical features of PKND, such as short stature under 150 cm, open cranial suture and fontanelle, club-shaped phalanges, and underdevelopment of midface. This is a case of a 7-year-old girl with PKND, who visited our clinic with the chief complaint of anterior Open-bite and generalized crowding. The patient had been diagnosed as PKND by an orthopedist and manifested characteristic clinical and radiographic features, such as open cranial suture and fontanelle, obtuse madibular gonial angle, frontal and occipital bossing, grooved palate, club-shaped phalanges, and short stature. Orthodontic treatment was not considered because patients with PKND show abnormal bone resorption and remodeling. Instead, removal of deciduous teeth near exfoliation and TFA were performed, and periodic check-up is planned to maintain good oral hygiene.

• Journal of the korean academy of Pediatric Dentistry
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• v.40 no.3
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• pp.177-184
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• 2013

Calcium hydroxide mixture medicaments can nearly be considered to be the ideal primary tooth filling material. However, long-term application of calcium hydroxide combinations as an intra canal medicament softens dentin. The aim of this study was to evaluate the effect of calcium hydroxide on the microhardness of root dentin of primary tooth. For the study, 60 extractedprimary incisors were divided into 3 groups (no medicament, calcium hydroxide/iodorform mixture, and calcium hydroxide/distilled water mixture). After the cleansing and shaping of canals, calcium hydroxide medicaments were applied and stored for different periods of time (1, 7, 30, 90 days). The root was horizontally sectioned into 2 mm thick specimens and the microhardness was measured using Vickers microhardness tester. The results were as follows : Root dentin microhardness of primary teeth decreased with long term exposure to calcium hydroxide medicaments according to the experimental period and showed statistically significance (p < 0.05). Root dentin microhardness of primary tooth filled with calcium hydroxide mixed with distilled water showed more decrease than filled with Vitapex and showed statistically significance (p < 0.05). Root dentin microhardness of a control group without exposure to calcium hydroxide decreased according to the experimental period and showed statistically significance (p < 0.05).

• Journal of the korean academy of Pediatric Dentistry
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• v.27 no.3
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• pp.444-456
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• 2000

To test the shear bond strength of a new "one-bottle adhesive" system to primary dentin two commercially available one-bottle adhesives (Prime & Bond NT, Single bond) and conventional three step system(Scotchbond Multi-Purpose Plus) were included for comparison. And We observe the interfacial morphology by scanning electron microscope. 90 primary molar teeth were embedded in acrylic and buccal and lingual surface were polished to 320 grit to create standardized dentin surface for testing. After bonding of composite resin to sample surfaces according to the manufacturer s direction and 1000 times thermocycling in dwell time 30 second, Shear bond strengths of adhesives to dentin were determined using universal testing machine and analyzed by ANOVA test. Another groups of specimens were treated by hydrochloric acid to secure the resin only and those tags were evaluated under SEM for their length and forms and the morphology of the bonding sites were also observed. The result are as follows. 1. Group I(Prime & Bond NT) showed higher shear bond strength than group iI(Single Bond) and III(Scotchbond Multi Purpose Plus) but no statistically significant difference was founded between groups(p>.05). 2. Relating long resin tags of $70-120{\mu}m$ were observed in samples of all groups under SEM. We could observed hybrid layer, resin tag and many lateral branches in every group. But, we observed in group III rare lateral branched than other two group and discontinuous hybrid layer.

• Journal of the korean academy of Pediatric Dentistry
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• v.29 no.3
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• pp.407-412
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• 2002

The primary cause of missing teeth vary depending on the region. The loss of posterior teeth is mainly due to dental caries, whereas that of the anterior teeth occur primarily due to trauma at the age of standing and walking and secondarily from the rampant dental caries. Particularly, reduction of the arch length in the cases of premature loss of primary teeth may compromise the eruption of succedaneous permanent teeth. This may result in crowding and impaction of the permanent teeth, and asymmetry of arch, thus a careful consideration for space maintenance should be made in such cases. Space maintainer is required in the case of premature loss of primary posterior teeth, because space loss result from the approximate and centrifugal movement of the neighboring teeth. Generally, in the case of primary incisor, space loss occurs when 1) tooth contact is relevant, 2) crowding in primary dentition is present, and 3) a primary incisor is lost before the eruption of primary canine. Contrarily, in the case of primary dentition with interdental space, space loss will not be observed, mostly when a primary incisor is lost after the eruption of primary canine. Thus, using a space maintainer in cases of premature loss of primary incisor has been introduced primarily not for the purpose of space maintaining but for an aesthetic purpose, prevention of parafunctional oral habits such as tongue thrust, and of pronunciation. Additionally, few case studies have been reported of space loss in cases of premature loss of primary incisor. This study is to report cases of the space loss following the premature loss of primary incisors observed in children.

• Journal of the korean academy of Pediatric Dentistry
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• v.27 no.4
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• pp.524-534
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• 2000

Deciduous teeth can be extracted for two reasons, one due to the physiologic resorption and the other by the inflammation at the apex after traumatic injury. Physiologic resorption may be different from pathologic resorption in timing and mechanism. Therefore we resumed the different features of physiologic and pathologic resorption root surfaces. Many previous studies showed micromorphology of resorbed surface of roots of deciduous teeth. But, few studies compared physiological and pathological root resorption surfaces. In this study, we carefully observed microscopic morphologies of those two different root surfaces by scanning electron microscope and histologic features by light microscope. The resultant differences between physiologic and pathologic resorption surfaces of deciduous teeth were as follows: 1. The morphology of pathologic resorption lacunae due to inflammation varied in size and shape with irregular boundaries compared with the physiologic areas from scanning electron microscope observations. 2. From light microscope observations, several large resorption fossae containing numerous resorption lacunae were found, whereas the resorption lacunae were irregular in shape with pathologic resorption surface. 3. Numerous multinucleated giant cells were closely attached to the physiologic resorption lacunae, whereas several kinds of mesenchymal cells with numerous inflammatory cells were found in the areas adjacent to the pathologic resorption surface. 4. Light microscope findings showed that compensating cementum formation took place along some of the areas of inflammatory dentinal resorption. In conclusion, several morphological differences were present between physiologic and pathologic root resorption surfaces of human deciduous teeth. The future studies should include cytochemistry to clarify the cellular roles in resorption process observations of pulpal surfaces of coronal and radicular dentin to and the changes that occur in each phase of human deciduous tooth resorption.

• Journal of the korean academy of Pediatric Dentistry
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• v.27 no.3
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• pp.438-443
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• 2000

Ectopic eruption should be understood as a change in the course of the normal eruption path of a dental bud at any moment its origin. An example of this alteration is the dental transposition, a rare and more specific dental anomaly that may be defined as a change of position between two teeth. This case shows ectopic eruption of transposed mandibular lateral incisor beneath primary first molar at the first transitional period of the mixed dentition The crown of the lateral incisor has tipped distally, compelling root resorption and exfoliation of the adjacent primary cuspid and primary first molar. The reason for such eruption is not clearly understood, but it may involve; (1)trauma history, (2)prolonged retention of the deciduous teeth, (3)premature exfoliation of the deciduous teeth, and (4)genetic factor. Treatment is divided into interceptive and definitive treatment. Ectopically erupting mandibular incisor tends to become transposed with the adjacent cuspid and thus seems to warrant early orthodontic intervention. Early treatment may obviate later extraction or transposition of the incisor and canine in the permanent dentition. Timing is an important factor to be considered regarding in the correction of the lateral incisor transposition. This case advocates treatment with an active orthodontic therapy at the early stage of the mixed dentiton, before the eruption of the permanent cuspid.