• Applied Microscopy
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• v.31 no.3
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• pp.287-305
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• 2001

To investigate a role of cartilage canals in osteogenesis and growth of the vertebrae, in human fetuses ranging from 50 mm to 260 mm crown rump length were studied by electron microscopy. The initial appearance of cartilage canals of the vertebral body was observed at 60 mm fetus. In 80 mm fetus, primary ossification center in the vertebral body was first noted. The vertebral body showed calcified chondrocytes surrounded by a tone of hypertrophied chondrocytes and deep canals which terminated in calcified matrix. Most hypertrophied chondrocytes in the centrum showed in various stage of degeneration in disorderly arrangement. At the blind end of deep canal, osteogenic cells, osteoblasts and chondroclasts were observed. Resorption of unmineralized cartilage septa was undertaken by perivascular cells within cartilage canals. The ruffled border of the chondroclast was restricted to resorption site of calcified cartilagenous matrix. The periosteal bone formation was followed by the appearance of primary center of the centrum at 120 mm fetus. The osteoblasts of the perichondrium started to lay down a thin membranous bony lamella on the outer surface of the osseous trabeculae of the centrum. The processes of bone formation in the vertebral bodies were found to possess morphological similarities to that occurring at secondary center of the epiphysis of a long bone. These results indicate that the connective tissue cells within the cartilage canals proliferate and differentiate into osteoblasts at the site of endochondral ossification of the vertebrae.

• Journal of the korean academy of Pediatric Dentistry
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• v.31 no.2
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• pp.256-261
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• 2004

Pulp canal obliteration(PCO) is seen commonly in dental pulp after traumatic tooth injuries and is recognized clinically as early as 3 monthly after injury. Pulp canal obliteration is characterized by deposition of hard tissue within the root canal space and yellow discoloration of the clinical crown. Opinion differs among practitioners as to whether to treat these cases upon early detection of PCO or to observe them until symptoms or radiographic signs of pulpal necrosis are detected. PCO may make root canal treatment necessary because of the development of apical periodotitis or for cosmetic reasons. If carefully executed, root canal treatment in teeth with an PCO is hightly successful and may act as a basis for internal bleaching. During a game, a 12-year-old girl was hit in the face. At that time, she was diagnosis a subluxation of the maxillary right central incisor. At the 24-month recall examination, a root canal of the tooth had been calcified and discolored gradually. We performed endodontic treatment to prevent perfect pulp canal obliteration and internal bleaching.

• Journal of Dental Rehabilitation and Applied Science
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• v.22 no.2
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• pp.173-180
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• 2006

Objectives The aim of this study is to compare the quality of root canal preparation completed using MFile-$System^{(R)}$ instrument ( Komet, Gebr.Brsaseler, Germany) and conventional stainless steel file in the canals of Maxillary molar teeth that had a canal curvature between $25^{\circ}$ or more Materials & Methods Buccal canals of 24 first and second maxillary molar teeth, extracted for periodontal and prosthetic reasons were used. Tissue fragments and calcified debris were removed from teeth by scaling and the teeth were stored in 10% formalin solution for 24 hour. Then, teeth were stored in saline until used. To be included the roots had to have completed formed apices and angle of curvature ranging between $25^{\circ}$ or more according to the criteria described by Schneider(1971). Palatal and Second mesiobuccal canals were not included. Teeth were embedded into transparent acrylic. The teeth were randomly divided into two experimental groups. All teeth were scanned by Dental CT (PSR9000N, Asahi, Japan) to determine the root canal shape before instrumentation. Image slices were prepared from the apical end point to the pulp chamber. The first two sections were 2 mm from the apical end of root and 2 mm below the orifice. Further section was recorded, dividing the distance between the sections of apical and coronal levels into two equal lengths. 12 teeth were instrumented using stainless steel fileand another 12 teeth were instrumented using MFile-$System^{(R)}$. Following the completion of the instrumentation, the teeth were again scanned and compared with the cross sectional images taken prior to canal preparation. Amount of transportation and centering ability was assessed. Student's t-test was used for statistical analysis. Result Less transportation occurred with MFile-$System^{(R)}$ rotary instrumentation than stainless steel instrument. MFile-$System^{(R)}$ had better centering ability than stainless steel instrument. Conclusion MFile-$System^{(R)}$ rotary instrumentation transported canals less and had good centering ability.

• Journal of the korean academy of Pediatric Dentistry
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• v.47 no.3
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• pp.337-343
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• 2020

Molar-incisor malformation (MIM) is a new type of root anomaly reported recently. The characteristics of MIM are dysplastic root formations, constriction of pulp chambers and presence of calcified matrices at the level of cementoenamel junction in permanent first molars and primary second molars. In some cases, permanent maxillary incisors are also affected. The permanent first molars of the patient in this case report were affected with MIM. Generalized pulp stones were observed in overall primary dentition. Micro-computed tomography (micro-CT) imaging and scanning electron microscope-energy dispersive X-ray spectrometer analysis were performed on the extracted mandibular first molar and maxillary primary second molar of the patient. Micro-CT images revealed the discontinuity of enamel directly connected to an accessory canal of the root.

• Korean Journal of Veterinary Research
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• v.31 no.2
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• pp.143-154
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• 1991

The present study was undertaken to provide basic data on fetal endochondral ossification for the native Korean cattle femur. This study was determined to the both earliest stages of chondrification and ossification by histochemical methods. The forty-five pairs of femur, from a series of embryos and fetuses ranging from 11 to 100mm in crown-rump(C-R) length, were used. These samples were divided into 9 groups. The groupings were based on C-R length, as the first grouping being 11~20mm, the second grouping being 21~30mm and so on. The results were as follows: 1. Alcianophility and PAS reaction were markedly increased in the perichondrium and interterritorial matrix in the 3rd group(C-R length 31~40mm). These reactions were decreased in the territorial matrix and in the adjacent area to the cartilage canal in the 5th group(C-R length 51~60mm). 2. Calcium deposits and collagen substances were observed initially in the 3rd group(C-R length 31~40mm). The calcium deposits and calcified cores were observed in the trabeculae of the proximal epiphyseal plate of the femur in the 8th group(C-R length 81~90mm).

• Journal of Korean Neurosurgical Society
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• v.48 no.2
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• pp.173-176
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• 2010

In this report, we introduce an undetermined fibrous tumor with calcification occurring in the cerebellopontine angle (CPA). A 51-year-old woman was admitted with a short history of dizziness. Computed tomography and magnetic resonance images revealed a $2{\times}2{\times}2\;cm$ sized mass at the left CPA which was round and calcified. There was no dura or internal auditory canal involvement. At surgery, the tumor was located at the exit of 7th and 8th cranial nerve complex. It was very firm, bright yellow and well encapsulated. Histologic findings revealed that the tumor was predominantly composed of fibrous component, scant spindle cells and dystrophic calcification. Immunohistochemical staining demonstrated positive for vimentin and negative for epithelial membrane antigen (EMA), S-100 protein, CD34, factor XIIIa and smooth muscle actin. The diagnosis was not compatible with meningioma, schwannoma, metastatic brain tumors, and other fibrous tumors. Although the tumor was resected in total, long term follow-up monitoring is necessary due to the possibility of recurrence.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.25 no.1
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• pp.159-170
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• 1995

Few cases of florid osseous dysplasia has been described as a condition that characteristically affects the jaws. It usually manifests as multiple radiopaque masses distributed throughout the jaws. Confusion exists about the relationship of florid osseous dysplasia, gigantiform cementoma, chronic sclersing osteomyelitis, sclerosing osteitis or multiple enostosis. Authors experienced a case of florid osseous dysplasia of the jaws in 52-year-old female on the basis of clinical, radiographic and histopathologic findings. The characteristic features are as follows : 1. In clinical examination, there was no clinical sign and symptoms except extracted area. And there was no facial asymmetry. 2. Radiograms show round or lobular dense radiopaque masses surrounded by radiolucent bands in lower molar teeth area bilaterally. And slight increased radiopacities in maxillary molar teeth area bilaterally. There was no expansion or thinning of buccal and lingual cortical bones. There is no displacement or resorption of involved teeth. In right side of mandible, mandibular canal is displaced inferiorly due to mass. 3. Photomicrograms show densely mineralized sclerotic acellular masses with empty lacunae. Pattern is suggestive of cementum, although it could be considered sclerotic bone. In the periphery, lesion consisting of moderately cellular fibrous tissue in which globular calcified products are deposited.

• Journal of Veterinary Clinics
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• v.18 no.3
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• pp.284-287
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• 2001

Three dogs referred to Veterinary Medical Teaching Hospital, Seoul National University were diagnosed as intervertebral disc disease. Physical examination, neurologic examination, survey radiograph, and myelography were performed in patients. Case 1 showed narrowing intervertebral space and calcified intervertebral disc material in survey radiograph. Case 2 showed increased opacity in the intervertebral opacity in survey radiograph. All of 3 cases showed extradural pattern during myelography. In survey radiography, radiographic signs consistent with intervertebral disc herniations include narrowing of the disc space and the dorsal intervertebral articular process joint space, small intervertebral foramen, increase opacity in the intervertebral foramen and extruded, mineralized disc material within the vertebral canal. Myelography is useful for evaluating the spinal cord and the cauda equina. Indication for myelography includes confirming a spinal lesion seen or suspected on survey radiograph, defining the extent of a survey lesion, finding a lesion not observed on survey radiograph, and distinguishing between surgical and nonsurgical lesion. In presentcases, two of three cases show radiographic signs of IVDD with survey radiograph and all of three case show extradural pattern during myelography. It is observed that intervertebral disc disease is one of the most important indication for radiographic examination and myelography of the vertebral column of small animals.

• Journal of the korean academy of Pediatric Dentistry
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• v.48 no.3
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• pp.352-358
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• 2021

Molar-incisor malformation (MIM) is characterized by malformation in the root with a normal crown. While MIM mostly occurs in the permanent first molar, it has also been reported in the maxillary central incisor and the primary second molar (PSM), but anatomical analysis of the primary teeth with MIM has not been studied to date. In this case report, a patient with MIM was reported, and an extracted PSM with MIM was analyzed with micro computed tomography (CT). A cervical constriction morphology of the cementoenamel junction (CEJ) can be observed in extracted PSM. In micro CT analysis, characteristics such a mineralized plate (cervical mineralized diaphragm) in the CEJ area, complex root canal morphologies, a calcified mass inside the pulp chamber, and constricted pulp chamber of crown portion were observed.

• Restorative Dentistry and Endodontics
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• v.47 no.2
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• pp.24.1-24.15
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• 2022

Objectives: Regenerative endodontic treatment is a clinical procedure aimed at biologically regenerating damaged root canal tissue of immature permanent teeth. This study aimed to report the outcomes of regenerative endodontic treatment performed by endodontic postgraduate students. Materials and Methods: Clinical and radiographic data of 27 patients, aged 10-22 years, who underwent regenerative treatment of immature permanent teeth from 2015 to 2019 were followed up, wherein clinical and radiographic examinations were performed for each patient. Postoperative success rate and tooth survival were analyzed, and the postoperative radiographic root area changes were quantified. Results: A total of 23 patients attended the dental appointments, showing that all teeth survived and were asymptomatic. Specifically, 7 periapical pathosis cases were completely healed, 12 were incompletely healed, and 4 cases failed. Moreover, significant differences were found between discolored and non-discolored teeth, and between the presence or absence of periapical radiolucency. Additionally, 3 anterior teeth showed complete closure of the apical foramen, while the apical foramen width was reduced in 17 teeth and failed in 3 teeth. Root length was also found to have been increased in 7 anterior and 4 posterior teeth, and the average length ranged from 4.00-0.63 mm in the anterior teeth, 2.85-1.48 mm of the mesial root, and 2.73-2.16 mm of the molar teeth distal root. Furthermore, calcified tissue deposition was observed in 7 teeth. Conclusions: A favorable outcome of regenerative endodontic treatment of immature permanent teeth with necrotic pulp was achieved with a high survival rate.