• The Journal of Korean Academy of Prosthodontics
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• v.22 no.1
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• pp.33-50
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• 1984

The purpose of this study was to investigate whether the ashed tooth powder is utilized as an alternative material of the implant to recovery the bony defect. For this purpose its biocompatibility was evaluated comparing to the synthetic calcium phosphate compounds, such as Syntograft and Calcitite, as well as the vacuum firing porcelain (Ceramco Inc.) which is anticipated to use as a matrix to aid sintering. Bony defects to exposure the bone marrow, $3{\times}5$ mm in size, were created in the right and left tibias of fifteen rabbits, and then the ashed tooth powder at $950^{\circ}C$, the porcelain powder, Syhtograft and Calcitite were inserted in the defects of twelve rabbits of the experimental group and the blood clot only was filled in the defects of three rabbits of the control group. The experimental and control rabbits were sacrificed at 1st, 2nd 3rd week after implantation and the histologic examination was performed. The ashed tooth powder in order to make the needed form of the implant was molded using the cylindrical mold 1 cm high, 1 cm in diameter under the pressure of $1000kg/cm^2$ and the ashed tooth powder was sintered at $1100^{\circ}C$ for 1 hour and the mixture of the porcelain powder and the ashed tooth powder at the weight ratio of 7:3, 6:4, 5:5, 4:6 were molded in the same manner and were sintered at $925^{\circ}C$. From this sintered material, square shaped implants were prepared in the dimension of $2{\times}4{\times}6mm$. The prepared implants were surgically placed in the subperiosteum of lateral surfaces of the right and left mandibular bodies. The dogs were sacrificed at 4 weeks, and then the specimens were examined using the light and scanning electron microscopes. The results of this study were obtained as follows: 1. Any inflammatory response was not noted after implanting of the ashed tooth powder, Syntograft, Calcitite and the porcelain powder during the whole experimental period after implantation. 2. Induction of the new bone formation was significantly shown in the ashed tooth powder, Syntograft and Calcitite. 3. The more the porcelain powder was contained in the implants, the more the porosity was and the bigger the pore size was under the scanning electron microscope. And there was ingrowing of the fibrous connective and the osteoid tissue. 4. The osteoid tissues were found to be directly fused to the implant of the ashed tooth powder, and the mixture implant of the porcelain powder and the ashed tooth powder at the weight ratio of 4:6 under the light and scanning electron microscopes.

• Journal of the korean academy of Pediatric Dentistry
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• v.32 no.4
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• pp.670-674
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• 2005

Supernumerary tooth develops as a result of abnormal proliferation of the dental lamina during the initiation stage of dental development. It could be a sporadic occurrence or a hereditary transmission. Supernumerary tooth occurs with a frequency of 1 to 3%. Generally, there is a 2:1 preference for boys. It is usually found in the anterior portion of the maxilla and may be associated with complications such as impaction, malposition of permanent teeth, formation of diastema, cysts and eruption into nasal cavity, The position of supernumerary tooth found in the anterior portion of the maxilla is determined by the axis of the tooth. One third of supernumerary tooth in the anterior portion of the maxilla has no possibility of eruption due to its invertedly impacted position. However, as long as the coronal part of the follicle remains intact, migration of supernumerary tooth is possible. The migration may occur into the palate, the premolar region, the sinus or the nasal cavity. Also, growth of vertical dimension of maxilla could make surgical approach difficult as time goes by For this reason, we have found invertedly impacted mesiodens moved to the vault of the palate in the two cases, and extracted supernumerary tooth surgically.

• Journal of the korean academy of Pediatric Dentistry
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• v.31 no.4
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• pp.651-658
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• 2004

Runx2 is a transcription factor in homologous with Drosophila runt gene and it is essential for bone formation during embryogenesis and a critical gene for osteoblast differentiation and osteoblast function. Runx2-haploinsufficency causes cleidocranial dysplasia (CCD). CCD is an autosomal-dominant inherited disorder characterized by hypoplastic clevicle and delayed ossification in fontanelles and wormian bones. Dental defects are possibly shown to CCD patients : multiple supernumerary teeth, irregular and compressed permanent tooth crowns, hypoplastic and hypomineralized defects in enamel and dentin, an excess of epithelial root remnants, the absence of cellular cementum, and abnormally shaped roots. In addition, delayed eruption of the secondary dentition is a constant finding. The aim of this study is to evaluate the role of Runx2 in the tooth development and eruption through analyzing the expression pattern of Runx2 by in situ hybridization during crown (late bell stage) and root formation of tooth, using postnatal day 1, 4, 7, 14 and 21 mice mandibular molar teeth. mRNA of Runx2-full length is expressed in dental follicle and surrounding tissue at postnatal day1 and 4. At postnatal day 7, it is expressed in ameloblasts of occlusal surface of enamel and bone area surrounding the tooth. In comparison with previous stage, at postnatal day 14, it is expressed in ameloblasts of proximal surface of enamel. At postnatal day 21 it's expression is observed only in bone area. mRNA of Runx2-typeII is not expressed. At postnatal day 1 and 7. At postnatal day 14 and 21, it's expression is observed in the bone area. In this study, we suggest that Runx2 have a relation of ameloblasts differentiation and an important role to tooth eruption made by dental follicle during intraosseous eruption stage. Also we can confirm that Runx2 has a role to bone formation.

• Food Science and Biotechnology
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• v.14 no.1
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• pp.94-98
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• 2005

Bone resorption surrounding tooth root causes tooth loss in periodontitis patients. Osteoclast has bone resorption activity. Effects of Artemisia asiatica on bone resorption induced by periodontopathogens, Porphyromonas gingivalis and Treponema denticola, were examined using co-culture systems of mouse osteoblasts and bone marrow cells. Addition of A. asiatica ethanol extract to bacterial sonicate abolished bacteria-induced osteoclastogenesis. To determine inhibitory mechanism of A. asiatica against osteoclastogenesis, effects of A. asiatica on expressions of osteoclastogenesis-inducing factors such as receptor activator of NF-${\kappa}B$ ligand (RANKL), prostaglandin $E_2\;(PGE_2)$, interleukin (IL)-1, and tumor necrosis factor (TNF)-${\alpha}$, in osteoblasts were examined. A. asiatica suppressed expressions of RANKL, $PGE_2$, IL-$1{\beta}$, and TNF-${\alpha}$ increased by each bacterial sonicate. These results suggest inhibitory action of A. asiatica against osteoclastogenesis is associated with down-regulations of RANKL, $PGE_2$ IL-$1{\beta}$, and TNF-${\alpha}$ expressions.

• Archives of Pharmacal Research
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• v.13 no.2
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• pp.211-213
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• 1990

To test flavonoids for antibacterial activity against oral micraorganisms, flavonoids, quercetrin and naringenin, were incorporated into two pharmaceutical preparations in the form of tooth paste. Samplees of dental plaque, the msot accused dental deposit which initiates the gingival and periodental diseases, were collected from the teeth surface of ten dental students at one week interval before and after using placebo, followed by two formulae of tooth paste containing 0.1% of quercetrin and naringenin (formulas I and II, respectively). The amount of dental plaque was assessed by the quigley and Hens index. Then plaque samples were subjected to bacteriological examination of Gram stain and plate counts of microorganisms. The amount of dental plaque was assessed by the Quigley and Hens index. Then plaque samples were subjected to bacteriological examination of Gram stain and plate counts of microorganisms. The results revealed that most of Gram negative cocci and bacilli were highly affected by the two formulae : the number of actinomycetes were decreased after using formula I and disappeared completely by the sue of formula II, while the number of Gram positive streptococci was highly decreased after the treatment with the two formulae. These results indicate a possible use of flavonoids to inhibit dental plaque formation.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.33 no.3
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• pp.256-263
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• 2011

Purpose: The purpose of this study was to evaluate the effectiveness of autogenous tooth graft materials after maxillary sinus bone grafts. Methods: The study involved 23 implants in 22 patients who visited the Department of Oral and Maxillofacial Surgery and the Department of Periodontics, Chosun University Dental Hospital, in 2008 and received autogenous tooth graft materials for maxillary sinus bone grafts. Results: For eight patients with maxillary bone graft materials prior to implant placement, the healing period averaged five months. For eleven patients with simultaneous maxillary bone graft and implant placement, eight patients received a second surgery, with an average healing time of six months. Three patients had a longer observation period with only a fixture implanted. Three patients who received only a bone graft required more time to implant placement because of the lack of residual bone and also for personal reasons. Only 5 patients had biopsies performed and complications such as infection and dehiscence healed well. The application of autogenous graft materials to the maxillary bone graft sites did not exert any significant effects on the success rates. When a mixture of graft materials was used, the post-surgical bone resorption rate was reduced. Histological analysis showed that new bone formation and remodeling were initiated during the three-to-six month healing period. Bone formation capacity increased continuously up to six months after the maxillary bone graft. Conclusion: According to this analysis, excellent stability and bone-forming capacity were seen in cases where autogenous materials were used alone or mixed with other materials. Autogenous tooth graft materials may be substituted instead of autogenous bones.

• Journal of the korean academy of Pediatric Dentistry
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• v.45 no.2
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• pp.144-153
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• 2018

The aim of this study was to understand the roles of Sonic Hedgehog (SHH) signaling during tooth root and periodontium formation. In this study, we generated the dental mesenchyme-specific Smoothened (Smo) activated/inactivated mice with the activity of Cre recombinase under the control of osteocalcin promoter. In the Smo activated mutant molar sections at the postnatal 28 days, we found extremely thin root dentin and widened pulp chamber. Picrosirius red staining showed loosely arranged fibers in the periodontal space and decreased cellular cementum with some root resorption. Immunohistochemical staining showed less localization of matrix proteins such as Bsp, Dmp1, Pstn, and Ank in the cementum, periodontal ligament, and/or cementoblast. In the Smo inactivated mutant mouse, there was not any remarkable differences in the localization of these matrix proteins compared with the wild type. These findings suggest that adequate suppressing regulation of SHH signaling is required in the development of tooth root and periodontium.

• International Journal of Oral Biology
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• v.41 no.2
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• pp.89-96
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• 2016

Tooth development shows dynamic morphological changes from the stages of cap to hard tissue formation and is strictly regulated during development. In the present study, we compared expression and localization of 3 major enamel matrix proteins in rats: amelogenin, enamel and ameloblastin. DD-PCR and RT-PCR revealed differential expression of the major proteins from the cap stage to root stage. Immunofluorescence staining results indicated that amelogenin was not detected in either inner enamel epithelium or reduced enamel epithelium, but highly immunoreactive in preameloblasts and ameloblasts; in addition, it was sporadically expressed in preodontoblasts abutting preameloblasts. Ameloblastin expression was also observed in not only differentiated ameloblasts but also osteoblasts. Immunoreactivity to ameloblastin in ameloblasts was strong in Tomes' processes. Enamelin was exclusively localized along the entire newly formed and maturing enamel. Enamelin was largely localized in near Tomes' processes and enamel rods in maturing enamel. Alendronate treatment resulted in down-regulation of amelogenin and ameloblastin at both transcription and translation levels; whereas, enamelin expression was unchanged in response to the treatment. These results suggested that amelogenin, ameloblastin and enamelin might be implicated in cell differentiation, adhesion of ameloblasts to enamel and enamel crystallization during enamel matrix formation, respectively.

• Journal of the korean academy of Pediatric Dentistry
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• v.26 no.4
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• pp.644-651
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• 1999

It is a relatively common clinical experience to see an unerupted maxillary central incisor. This phenomenon is apparent at the dental age of almost eight years and over. Among the possible cause for failure of eruption, ectopic development of the tooth germ is mentioned. This is not fully understood but trauma or periapical imflammation of primary predecessors is accepted. The case with no history of trauma may be impacted by the periapical imflammation of primary predecessors. For bringing into the tooth eruption and the continued normal root developement by the Hertwig's epithelial root sheath, there are early considered of surgical invention and orthodontic traction with removable appliance. We reported successful treatment for inverted maxillary central incisor with proper eruption and normal root developement by forced eruption using removable appliance. But further observation will be required to evaluate the final root developement state and amount of keratinized attachment gingiva.

• International Journal of Oral Biology
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• v.36 no.3
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• pp.135-141
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• 2011

Hertwig's epithelial root sheath (HERS) consists of bi-layered cells derived from the inner and outer dental epithelia and plays important roles in tooth root formation as well as in the maintenance and regeneration of periodontal tissues. With regards to the fate of HERS, and although previous reports have suggested that this entails the formation of epithelial rests of Malassez, apoptosis or an epithelial-mesenchymal transformation (EMT), it is unclear what changes occur in the epithelial cells in this structure. This study examined whether HERS cells undergo EMT using a keratin-14 (K14) cre:ROSA 26 transgenic reporter mouse. The K14 transgene is expressed by many epithelial tissues, including the oral epithelium and the enamel organ. A distinct K14 expression pattern was found in the continuous HERS bi-layer and the epithelial diaphragm were visualized by detecting the ${\beta}$-galactosidase (lacZ) activity in 1 week postnatal mice. The 2 and 4 week old mice showed a fragmented HERS with cell aggregation along the root surface. However, some of the lacZ-positive dissociated cells along the root surface were not positive for pan-cytokeratin. These results suggest that the K14 transgene is a valuable marker of HERS. In addition, the current data suggest that some of the HERS cells may lose their epithelial properties after fragmentation and subsequently undergo EMT.