• Restorative Dentistry and Endodontics
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• v.32 no.5
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• pp.459-468
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• 2007

Protein microarray or protein chips is potentially powerful tools for analysis of protein-protein interactions. APin cDNA was previously identified and cloned from a rat odontoblast cDNA library. The purpose of this study was to investigate the APin-protein interactions during ameloblast differentiation. Protein microarray was carried with recombinant APin protein and MEF2, Aurora kinase A, BMPR-IB and EF-hand calcium binding protein were selected among 74 interacting proteins. Immortalized ameloblast cells (ALCs) were transfected with pCMV-APin construct and U6-APin siRNA construct. After transfection, the expression of the mRNAs for four proteins selected by protein micoarrays were assessed by RT-PCR. The results were as follows: 1. APin expression was increased and decreased markedly after its over-expression and inactivation, respectively. 2. Over-expression of the APin in the ALCs markedly down-regulated the expression of MEF2 and Aurora kinase A, whereas their expression remained unchanged by its inactivation. 3. Expression of BMPR-IB and EF-hand calcium binding protein were markedly increased by the over-expression of the APin in the ALCs, whereas expression of BMPR-IB remained unchanged and expression of EF-hand calcium binding protein was markedly decreased by its inactivation. These results suggest that APin plays an important role in ameloblast differentiation and mineralization by regulating the expression of MEF2, Aurora kinase A, BMPR-IB and EF-hand calcium binding protein.

• Journal of Korean Dental Science
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• v.8 no.2
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• pp.74-81
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• 2015

Purpose: In osteoclast differentiation, actin-rich membrane protrusions play a crucial role in cell adhesion. Odontogenic ameloblast-associated protein (Odam) contributes to cell adhesion by inducing actin rearrangement. Odam-mediated RhoA activity may play a significant role in multinucleation of osteoclasts. However, the precise function of Odam in osteoclast cell adhesion and differentiation remains largely unknown. Here, we identify a critical role for Odam in inducing osteoclast adhesion and differentiation. Materials and Methods: The expression of Odam in osteoclasts was evaluated by immunohistochemistry. Primary mouse bone marrow and RAW264.7 cells were used to test the cell adhesion and actin ring formation induced by Odam. Result: Odam was expressed in osteoclasts around alveolar bone. Odam transfection induced actin filament rearrangement and cell adhesion compared with the control or collagen groups. Overexpression of Odam promoted actin stress fiber remodeling and cell adhesion, resulting in increased osteoclast fusion. Conclusion: These results suggest that Odam expression in primary mouse osteoclasts and RAW264.7 cells promotes their adhesion, resulting in the induction of osteoclast differentiation.

• The Journal of the Korean dental association
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• v.10 no.4
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• pp.209-212
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• 1972

The effect of pyridoxine on the incisors were histochemically studied for the purpose of identifying the phosphoric acid. The microscopic observations were carried out by means of phosphoric acid reaction(Serraet Queiroz-Lopes method), mucoprotein reaction (Clara method), periodic acid-Schiff reaction (McManus method), methylen blue stain and hematoxylin-eosin stain. In the experimental result, it was found that phosphoric acid reactions of ameloblast, Tomes' process and preenamel were remarkably increased after pyridoxine administration.

• Applied Microscopy
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• v.46 no.1
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• pp.58-66
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• 2016

Thymosin ${\beta}4$ ($T{\beta}4$) has been recently reported to play a role in dentinogenesis by regulating the expression of dentin matrix proteins. Based on previous studies, it is hypothesized that $T{\beta}4$ is associated with the formation of the enamel matrix and thus plays an important role in ameloblast. However, there is no report on the function of $T{\beta}4$ during tooth development so far. Therefore, in this study, we aimed to investigate the expression of $T{\beta}4$ and its function in ameloblasts during mouse tooth development. $T{\beta}4$ was expressed strongly in the tooth bud at the bud stage and in the dental lamina and oral epithelium at the cap stage. In advanced bell stage at postnatal day 4, large elongated ameloblasts were observed and the expression of the $T{\beta}4$ protein was the highest, with the enamel being was thicker than that in the early bell stage. The length of ameloblasts increased from the presecretory to the secretory stage and decreased from the maturation to the protective stage. These results suggest that $T{\beta}4$ participates not only in the proliferation of oral epithelial cells during the early stage of tooth development but also regulates enamel protein secretion in ameloblasts and enamel mineralization.

• International Journal of Oral Biology
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• v.34 no.1
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• pp.21-28
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• 2009

Mutations in DLX3 are associated with both autosomal dominant hypoplastic hypomaturation amelogenesis imperfecta (ADHHAI) and tricho-dento-osseous (TDO) syndrome. ADHHAI is caused by a c.561_562delCT (2bp-del DLX3) mutation whereas TDO syndrome is associated with a c.571_574delGGGG (4bp-del DLX3) mutation. However, although the causal relationships between DLX3 and an enamel phenotype have been established, the pathophysiological role of DLX3 mutations in enamel development has not yet been clarified. In our current study, we prepared expression vectors for wild type and deletion mutant DLX3 products (4bp-del DLX3, 2bp-del DLX3) and examined the effects of their overexpression on the expression of the enamel matrix proteins and proteases. Wild type DLX3 enhanced the expression of matrix metalloprotease 20 (MMP20) mRNA and protein in murine ameloblast-like cells. However, neither a 4bp-del nor 2bp-del DLX3 increased MMP20 expression. Wild type DLX3, but not the above DLX3 mutants, also increased the activity of reporters containing 1.5 kb or 0.5 kb of the MMP20 promoter. An examination of protein stability showed that the half-life of wild type DLX3 protein was less than 12 h whilst that of both deletion mutants was longer than 24 h. Endogenous Dlx3 was also found to be continuously expressed during ameloblast differentiation. Since inactivating mutations in the gene encoding MMP20 are associated with amelogenesis imperfecta, the inability of 4bp-del or 2bp-del DLX3 to induce MMP20 expression suggests a possible involvement of such mutations in the enamel phenotype associated with TDO syndrome or ADHHAI.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.6 no.1
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• pp.33-38
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• 1976

The author observed the effects of the cobalt-60 irradiation on the amelogenesis and dentinogenesis of the albino rat fetuses by means of histological and histochemical methods. Females in oestrus were mated overnight and examined the next morning for evidence of copulation. The lower left abdomen of mothers were exposed to cobalt-60 irradiation on the 10th day of gestation, l00R 200R and 300R respectively. The fetuses were removed from the mothers on the 18th day of gestation. The employed histochemical methods were PAS reaction, colloidal iron reaction, aldehyde fuchsin stain, α-amino acid reaction, -SH radical reaction and methyl- green pyronin stain. The results were as follows; 1. The group irradiated by l00R made no histological differences in comparison with the control group. 2. Increasing the irradiation to 200R, abnormal dentin formation occured, and resulted in enamel hypoplasia and in atrophy and necrosis of odontoblasts. In dentinal papilla, the dilation and the degeneration of the blood vessels, excessive reticular atrophy and osteodentin were revealed. 3. With the more irradiation (200R-300R), the positive material of PAS, α-amino acid and aldehyde fuchsin tended to decrease in the ameloblast and the odontoblast. No significant changes appeared in DNA, the stainability of methylgreen pyronin.

• Restorative Dentistry and Endodontics
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• v.8 no.1
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• pp.61-68
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• 1982

This study was undertaken to compare the histopathological effects of the fractionated doses of 2,400, 4,800 and 7,200 rads of Cobalt-60 irradiation on the teeth of the sixty eight rats (Wester strain), weighing approximately 130gm. They were devided into four groups; no irradiation as a control (Group I) and others (Group II, III, and IV) which received different doses of radiation using 1.25 Mev RAC-120 Cobalt-60 Teletherapy Unit with exposure dose rate 69 rads/min, TSD 80cm. Experimental animals received 600 rads every three days until the total dosage of their groups were reached. Experimental animals were sacrified at the 1st day, 1st, 2nd, 3rd, 4th, 5th and 6th week irradiation. The following histopathologic findings were obtained: 1. The Group II, received 2,400 rads, showed no histopamologic changes essentially same as those of the control Group. 2. In the Groups III and IV, received 4,800 rads and 7,200 rads, disarray of the normal palasading arrangement of the odontoblastic cells, vacuolar degeneration in the odontoblastic layer, osteodentin and dentinal niches in the anterior teeth were observed. 3. There were no distinct changes in the posterior teeth in the Groups III and IV. 4. The ameloblast cells seemed to be less sensitive to radiation damage than the odontoblast cells.

• Journal of the korean academy of Pediatric Dentistry
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• v.3 no.1
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• pp.12-17
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• 1976

The study is about the effect of tetracycline-HCl on the amelogenesis and the dentinogenesis of the albino rats by means of histochemistry and fluorescence microscopy. Females in oestrus were mated overnight and examined the next morning for evidence of copulation. The mothers were intraperitonealy injected with a single dose of tetracycline-HCl from the eighth to tenth day of gestation. The heads of new born rats were fixed in Carnoy's solution and 10% formalin solution. The staining methods were alizarin red S stain, PAS reaction, colloidal iron reaction, Morin's stain and hematoxylin-eosin stain, The results were as follows: 1. By the single injection of tetracycline, the matrix formation of enamel and dentin were disturbed, and the shape and arrangement of ameloblast and odontoblast were distorted. 2. It seemed that, with the higher dose of tetracycline, the positive materials of PAS reaction were increased in the disturbed enamel and dentin matrix, but those of alizarin red S stain and colloidal iron reaction were decreased. 3. The fluorescence intensity in the disturbed enamel and dentin matrix were higher than the other areas and appeared to increase gradually with the higher dose of tetracycline.

• Journal of the korean academy of Pediatric Dentistry
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• v.11 no.1
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• pp.131-143
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• 1984

150 rats weighting about 150gm were devided into control group of 80 and experimental group of 70. Control group was subdivided into the irradiated vitamin D injection group and X-ray irradiated group. Experimental group was given 2.0mg ergocalciferol by four intramuscular injection prior to X-ray irradiation with single 800 rads and 1,500 rads respectively. Experimental animals from each group was sacrificed after 1, 3, 7, 14, and 28 days and their incisors were investigated by histopathological examination. The results were as follows; 1. In the irradiated groups, it showed dentin hypoplasia and formation of dentinoid substance caused by degeneration of odontoblast at the early stage. Especially, 1,500 rads group which was severely effected showed formation of osteoid dentin at the apical portion and severe injuries of dental papilla at the first week. 2. In the vitamin D2 administration group, it showed thinned dentin layer at the early stage but, taking time, predentin and dentin layer was thickened. At the fourth week, dentin was chiefly composed of interglobular dentin, especially in the lingual portion. 3. Using in combination of overdose vitamin D2 administration and X-ray irradiation, it effected severely odontoblast, undifferentiated mesenchymal cells around tooth germ and pulp tissue. At the early stage, dentin layer was thinned but, taking time, it was thickened and composed of interglobular dentin caused by calcification of predentin layer. 4. In 800 rads irradiation after the overdose vitamin D2 administration, it showed formation of osteoid dentin in the lingual portion at the first week. In the 1,500 rads irradiation after the overdose vitamin D2 administration, it showed formation of osteoid dentin and degeneration of ameloblast in both buccal and lingual portion at the first week, and enamel hypoplasia caused by edema and loss of polarity of ameloblasts at the second week. 5. By the entire experiment, the overdose vitamin D2 administration and X-ray irradiation effected severely odontoblasts, undifferentiated mesenchymal cells of dental papilla, and primitive cells of tooth germ among the dental tissue. Especially using combination of overdose vitamin D2 administration and X-ray irradiation also effected ameloblasts, resulting in enamel hypoplasia.

• Journal of dental hygiene science
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• v.21 no.1
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• pp.45-51
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• 2021

Background: Periodontal disease, also known as gum disease, is a major dental inflammatory disease with a very high prevalence; it is the main cause of tooth loss. Therefore, diagnostic biomarkers that can monitor gum inflammation are important for oral healthcare. Since the gingival crevicular fluid (GCF) adequately reflects changes in the periodontal environment, they have become a target for the development of effective diagnostic biomarkers for periodontitis. In the present study, the level of the target molecules suggested as diagnostic biomarkers for periodontitis were analyzed in GCF samples collected from healthy individuals and periodontitis patients. In addition, useful targets for the diagnosis of periodontitis were evaluated. Methods: GCF samples were collected from healthy individuals and periodontitis patients using absorbent paper points. SDS-PAGE and Coomassie staining were performed for protein analysis. The protein concentrations of GCF specimens were determined using the Bradford method. The levels of the target molecules appropriate for diagnosing periodontal disease were measured by ELISA, according to the manufacturer's protocol. Results: The protein concentration of GCF collected from periodontitis patients was 3.72 fold higher than that in an equal volume of GCF collected from healthy individuals. ELISA analysis showed that the level of interukin-6 (IL-6), IL-8, metalloproteinases 2 (MMP-2), MMP-9, tumor necrosis factor-alpha (TNF-α), azurocidin, and odontogenic ameloblast-associated protein (ODAM) were higher in the GCF samples from the periodontitis patients than in those from the healthy individuals. However, the level of IL-6 and TNF-α were relatively low (> 5 pg/ml). The prostaglandin E2 (PGE2) levels were not significantly different between the two GCF samples. Conclusion: These results indicate that IL-8, MMP-2, MMP-9, azurocidin, and ODAM are potentially useful diagnostic biomarkers for periodontitis; combining multiple biomarkers will improve the diagnostic accuracy of periodontitis.