Hydroxyapatite (HA) coatings on Ti implants are made by the physical methods, mainly plasma spraying. We have developed a new chemical coating technique, thermal decomposition method. This method consisted of applying HA or perovskite (CaTiO₃) coating solution containing organometals, phosphate ester (only in HA solution), and organic solvents onto the surface of Ti and then sintered it at 650°C. The process was repeated several times. The thin and homogeneous layer included an initial CaTiO₃ layer with a thickness of 0.6 μm followed by an HA layer (2.4 μm) on top. The underlying CaTiO₃ layer reduced oxidation of the Ti substrate and enhanced stability of the coating.

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This paper overviews the present status on therapy of regenerative medicine which is based on tissue engineering. Tissue engineering is a biomedical form which enables cells to promote their proliferation and differentiation, resulting in induction of tissue regeneration. The scaffold of 3-dimensional porous material for cells with or without the controlled release system of growth factor is applied to induce tissue regeneration in vivo. Some data of bone tissue regeneratio are introduced to emphasize significant role of growth factor release technology in the therapy of regenerative medicine bone.

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Fluoride-releasing materials can be expected to inhibit secondary caries and enhance remineralization of decalcified dentin underneath restorations. The aim of this study was to evaluate the inhibitory effect on secondary caries and remineralization of decalcified dentin by fluoride-releasing adhesives. Two commercial fluoride-releasing adhesives, Reactmer bond (RB, Shofu) and One-up bond F (OB, Tokuyama), and a commercial adhesive without fluoride release, Mac-bond II (MB, Tokuyama), were used in this study. For examination of the inhibitory effect, class V cavities were prepared on extracted human premolars and restored with a restorative material following the application of each adhesive. The restored teeth were incubated in bacterial medium for 14 days after storage for 14 days at 37°C, 100% humidity. For examination of remineralization of decalcified dentin, decalcified dentin was promoted by using a bacterial caries induction system at the cavity wall. The cavities were then restored with resin composite after application of each adhesive and incubated for 4 weeks at 37°C, 100% humidity. Microradiographs in the inhibitory test showed an acid-resistant layer adjacent to the restoration in the caries-like lesions. The acidresistant layers in the RB and OB groups with fluoride release were thicker than that in the MB group. Microradiographs in remineralization tests showed that the radiopacities of the decalcified dentin layers in the RB and OB groups were significantly higher than that in the MB group without fluoride release. These results indicated that fluoride-releasing adhesives are effective in inhibiting wall lesions and in enhancing the remineralization of decalcified dentin.

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The concept of minimal intervention dentistry has evolved as a consequence of our increased understanding of the caries process and the development of adhesive restorative materials. Recently, new concepts of treatments for dentin caries by use adhesive resins and glass-ionomer cements have been proposed. However, new hard tissue, indicated as the result of applying calcium hydroxide or adhesive resins and/or sterilized by the mixed drugs, formed with a tunnel defect frequency present, running from the medicament interface to pulp. These reports suggest the urgent necessity for us to the establishment of the biological dentin regeneration therapy like the Modified Sealed Restoration (MSR). In this review, we reported “In vivo dentin regeneration by adhesive resin containing EVA+C” and “Future approaches to establish the dentin regeneration therapy”.

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Dental trauma in childhood requires emergency treatment that might range from a simple repositioning, through replantation, to root as well as pulp treatment and apexification depending on severity of the injury. The trauma may be complicated with the existence of supernumerary teeth, and orthodontic treatment other than the management of trauma may be needed either for complication of the traumatized teeth or already existed occlusion problems. We report the management and long-term follow-up of a rare case in a child with traumatically avulsed maxillary incisor accompanied by mesiodens. The patient had a severe trauma to the face, which resulted in avulsion of the maxillary central incisor. Immediate replantation within 30 min after the trauma was performed. Radiographic examination also showed the mesiodens. Since external resorption started during follow-up, and electric pulp testing indicated negative response, we performed root treatment and apexification by calcium hydroxide. The mesiodens was extracted after the stabilization of the patient, followed by orthodontic treatment for the maxillary protraction. Although ankylosis occurred in long-term follow-up, no discomfort in the daily life with good prognosis was noticed.

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Although replantation of avulsed primary teeth is described as a contraindication in some books, there have been reports that patients had uneventful courses after replantation of avulsed primary teeth until eruption of the succeeding permanent teeth. We replanted an avulsed primary central incisor and followed up the patient until eruption of the succeeding permanent incisor. The patient was a boy aged 2 years and 1 month old at the initial visit. He fell from a chair and hit the maxillary incisor region. At the injury, the right primary central incisor was avulsed, and the patient came to the clinic after preserving the lost tooth in milk. Since the patient's parent strongly wished replantation of the tooth at the initial visit, we carefully explained the risk of infection after replantation, obtained the parent's consent, and replanted and splited the tooth. No particular adverse clinical problems were observed during the follow-up period, and the succeeding permanent tooth erupted nearly at its normal position.

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Although it has been known that amelogenin gene is expressed in ameloblastoma, the precise expression pattern of X and Y amelogenin genes (AMGX, AMGY) in this tumor has not yet identified. In this study, we analyzed amelogenin gene expression in 19 samples (9 male, 10 female) of oral ameloblastomas by RT-PCR and detect the chromosomal origin of amelogenin mRNA by restriction enzyme digestion of the RT-PCR product. All tumor samples expressed amelogenin mRNA. We could detect increased level of AMGY expression in all male samples, higher than that of AMEX. It is an interesting finding as in normal male tooth development, the expression of AMGY is very much lower than that of AMGX. We postulate that epigenetic change of sex chromosomes may have some correlations with tumorigenesis of ameloblastoma. We also discuss the other possible mechanisms and points for future studies on this the change in expression pattern.

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Five-year survival rates of oral cancer are not improving in spite of the progression of multidisciplinary treatment, because distant metastasis is the major cause of death in individuals suffering cancer. Therefore, early detection of metastasis at cervical lymph nodes and choosing appropriate treatment for advanced cases are highlighted for reducing deaths due to oral cancer and keeping QOL after treatment. First, actual condition of the micrometastasis in the cervival lymph nodes was analyzed with semiserial sectioning and its detection rate was improved with genetic diagnosis. SCC antigen mRNA is found to be a suitable marker of oral cancer. Next, I applied the sentinel node navigation surgery using intraoperative real-time genetic diagnosis. In order to further improve diagnostic accuracy, an optimal gene marker set was identified by means of a whole genome-wide microarray gene-expression profiling, which can detect common upregulated and downregulated genes in oral cancer. I believe that the genetic diagnosis is pivotal for choosing appropriate treatment, especially for individuals diagnosed with oral cancer.

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ING1 gene, the founding member of the ING tumor suppressor family, was originally identified through subtractive hybridization between normal mammary epithelial cells and breast cancer cell lines, and subsequent in vivo selection of genetic suppressor element that displayed oncogenic features. The four additional members of the ING family (ING2-5) were recently identified and all the gene products contain a highly conserved plant homeodomain (PHD) finger motif in the carboxy (C)-terminal end. Although exact functions of ING family genes have not been clarified, the gene products are involved in transcriptional regulation, apoptosis, cell cyle, angiogenesis and DNA repair through p53-dependent and -independent pathways and constituting complexes with histone acetyltransferases (HAT) and histone deacetylases (HDAC).

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The objective of our study was to assess the possibility of prognostication and monitoring of oral squamous cell carcinoma by microsatellite blood assay. DNA from normal and tumorous tissues and serum DNA obtained at three time points (preoperatively, postoperatively, and 4 weeks postoperatively) from 64 patients with oral squamous cell carcinoma was examined at nine microsatellite loci. Thirty-eight (59%) DNA samples from tumorous tissues and 52% from serum showed allelic imbalances in at least one locus. Patterns of allelic imbalances in serum DNA were matched to those detected in tumor DNA. Of them, allelic imbalances were frequently detected preoperatively (44%, 28/64), and postoperatively (20%, 13/64). Moreover, among 12 cases with allelic imbalances during the postoperative period, six had no evidence of an allelic imbalance 4 weeks postoperatively, and they had no recurrence and were disease free. In contrast, six patients with allelic imbalance-positive DNA 4 weeks postoperatively have died with distant metastasis within 44 weeks. Thus, our results suggest that the assessment of microsatellite status in serum DNA could be a useful predictive tool to monitor disease prognosis.

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The early development of alligator odontogenesis shows embryological ‘the Biogenetic law’. The swelling of the oral epithelium formed in the medial nasal process. It contained many cell deaths without teeth development at (Ferguson) stage 16. This stage compared to the horny teeth of Lamprey. At stages 17-19, the dental lamina developed from the oral epithelium and the enamel organ-like structure raised from it. The teeth developed just under the organ is composed of only collagen, so called dentine teeth. This stage compared to the fish tooth with the absence of enamel organ. After stage 27, the enamel organ completely developed and formed the tooth crown with the enamel and dentine. The completed teeth had long roots about 2 to 3 times longer than the crown height. Hertwig's epithelial sheath grew opposite to the enamel organ. All these observations suggested that the crown forming enamel organ and Hertwig's epithelial sheath developed in the symmetry through evagination (swelling) and invagination of the oral epithelium, respectively, based on the concept of the body plan.

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The stratum intermedium develops as flattened cell layer on the proximal side of the ameloblast layer during the bell stage of tooth development. Stratum intermedium cells strongly express alkaline phosphatase (ALP) activity and have been considered to play a complementary role in the enamel mineralization, however the origin and/or the role of these cells have not been elucidated. In the present study, we focused on the lineage of stratum intermedium cells in continuously growing rodent incisors and analyzed it by using DiI tracers experiment and using the incisors organ culture. The results indicated that some stratum intermedium cells were originated from the inner enamel epithelium. Immunohistochemical and in situ hybridization studies showed that the stratum intermedium cells expressed the Notch-1, Notch-2, and Hes1, while the inner enamel epithelium and ameloblasts expressed their ligands Jagged-1. Furthermore, we examined th role of Notch signaling in the development of the stratum intermedium cells by use of the dental epithelial cell line, HAT-7. Recombinant Jagged1 protein enhanced the appearance of the stratum intermedium cells in HAT-7. On the other hand, anti-sense Notch1 decreased the number of stratum intermedium cells. Taken together, we propose a hypothesis that the lineage of the stratum intermedium differentiates from the ameloblasts lineage through Notch signaling.

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Tooth root formation is initiated by the elongation of Hertwig's epithelial root sheath (HERS). HERS cells are widely accepted to control root formation, but the mechanisms regulating HERS growth have not been elucidated. To solve this problem, we have established a new culture method for postnatal mouse mandibular molars and, using it, examined the role of insulin-like growth factor-I (IGF-I) during tooth root formation. Our immunohistochemical study revealed the specific localization of the IGF-I receptor in HERS in the tooth root. In control cultures of molars prepared from postnatal 5- and 20-day-old mice, normal development of both HERS and periodontium proceeded as seen in vivo. However, the presence of 100 ng/ml IGF-I in the culture medium resulted in further elongation of HERS and increased cell proliferation in its outer layer of 5-day-old mice molars, and in promotion of cellular cementogenesis at the root surface of 20-day-old mouse molars. Thus, our results show that IGF-I played different roles depending on the stage of root formation

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In this study, we have developed a tooth regeneration model derived from mouse tooth germ cells based on tissue engineering. Lower first molars from DDY mice embryos at E 14 were used. Biodegradable Polyglycolate acid (PGA) scaffolds were fabricated, seeded with dissociated the first molars cells, and implanted into the subcapsular layer of kidney in an adult mouse where they allowed to develop over 3, 5, 7, and 14 days. We present histological analyses characterizing tissue-engineered tooth (TE-tooth). Histological analysis of 14 day implants tissue revealed mineralized enamel and dentin layer were apparent, of the kind of found in normally developing teeth.

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In the present study, we examined to identify down-regulated genes between pre- and post dental papillae by microarray analysis in order to identify genes involved in tooth morphogenesis. The dental papilla tissues obtained from E16, E18, P03 and P10 of ICR mice were used for microarray analysis. Microarray analysis showed that the number of up-regulated genes ranged from 860 to 2214 from E16 to P10 and was decreased following the tooth morphogenesis. On the other hand, the number of down-regulated genes ranged from 1337 to 2924, and number of down-regulated genes was the highest (2924 genes) during E18 and P3. The results suggest that the reduced or disappeared genes in dental papilla between P0 and P3 are associated with forming and calcifying the dentin of tooth crown and regeneration of tooth.

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Statement of the problem: Early detection of potentially malignant epithelial lesions (PMELs) is aimed at improving survival rates as carcinogenesis is a multistep process and prevention is possible if these lesions are detected at an early and reversible stage of the disease. Objectives: This prospective clinical study was designed to determine the prevalence of bilateral mirror-image PMELs in patients presenting with unilateral PMELs clinically. A modified brush biopsy technique was employed to detect early cytological epithelial changes if any, in the contralateral normal oral mucosa. Materials and method: Sixty individuals presenting with unilateral PMELs were selected for this study. These comprised 30 (50%) Indians, 24 (40%) Chinese, 5 (8.3%) Malays and one (1.7%) Nepalese. All selected cases had histopathological confirmation of their primary existing lesion(s) as inclusion criteria in this study. Cases which had subsequently presented with a lesion contralateral to the existing lesion were also subjected to scalpel incisional biopsy on this second lesion. The remaining cases which presented with a unilateral PMEL at the time of this clinical study were subjected to a brush biopsy on the clinically normal looking mucosa contralateral to the existing lesion. Results: A total of 70 lesions were detected in 60 patients. The most common PMEL found was oral lichen planus. Of the 60 patients studied, 26 exhibited mirror-image lesions either metachronously (73%) or synchronously (27%). The remaining cases that had undergone brush biopsy on the contralateral side to the existing PMEL yielded normal histological results. Conclusions: Present findings demonstrated that patients presenting with PMELs in the upper aerodigestive tract are at greater risk of developing a second lesion most probably on the contralateral mirror-image site. However the efficacy of brush biopsy method in detecting epithelial changes remained inconclusive due to the small sample examined.

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Statement of problem: Angiogenic squamous dysplasia (ASD), a qualitative distinct form of angiogenesis, was first described in pre-invasive bronchial mucosa of high-risk individuals. It is characterized histologically by the presence of capillary tufts that are closely juxtaposed to and projecting into the dysplastic bronchial epithelium. Objective: To determine whether ASD occurs in oral epithelial dysplastic lesions. Methods: Sixty cases of potentially malignant oral epithelial lesions comprising 20 mild epithelial dysplasia (ED), 20 moderate ED and 20 severe ED (inclusive of carcinoma-in-situ), and 10 normal oral mucosa (as normal controls) were retrieved from the archives of the Department of Oral Pathology, Oral Medicine & Periodontology, Faculty of Dentistry, University of Malaya, and the Cancer Research Centre, Institute for Medical Research, Kuala Lumpur, Malaysia. The grading of oral ED was in accordance with the recommendations of the World Health Organization. For all selected cases, new 5 micron thick sections were prepared for H&E staining, and for immunohistochemistry with three vascular markers, CD31, CD34 and CD105, with appropriate positive and negative controls. The established criteria for identification of ASD was applied. Results: ASD was identified in parts of severe oral ED, but was absent in normal oral epithelium, mild and moderate oral ED. About 65% of these severe oral ED cases were from individuals with high-risk habits. As with bronchial ASD, the capillaries typically formed CD31- and CD34-positive projections or loops that abut onto the overlying dysplastic oral epithelium causing the latter to assume a papillary surface configuration. Unlike bronchial ASD which occurs in respiratory-type epithelium, oral ASD was found in keratinzed stratified squamous epithelium. CD105 confirmed the presence of neoangiogenesis. Conclusions: Present findings confirm that ASD can occur in oral severe ED. It also demonstrates that this angiogenic abnormality is not unique to bronchial mucosal dysplastic lesions.

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A clinical follow-up study on traumatized young permanent teeth which treated by surgical endodontics was made. These teeth had progressive root resorption, ankylosis, or endodontic-periodontic lesions. The cases included 3 teeth from 3 patients aged 8 to 10 years at their initial visits. The treatments were curettage and resin filling of resorption cavities before intentional tooth replantation or surgical extrusion. Successful treatment relies on the complete removal of granulation tissue or the protection of resorption cavities by resin filling, and the proper splinting.

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For the bone regeneration, tissue engineering approach combines cells capable of osteogenic activity with an appropriate scaffold. We developed a biodegradable sponge composite (b-TCP/CS) by combining â-tricalcium phosphate (â-TCP) granules and collagen. Human mesenchymal stem cells (MSCs) were cultured within b-TCP/CS scaffolds and collagen sponge (CS) scaffolds, we investigated the alkaline phosphates (ALP) activity and the expression of osteogenic markers using RT-PCR. Furthermore, MSCs- loaded b-TCP/CS and CS were implanted under the back skin of nude mice for 4 and 12 weeks, and then removed for histological evaluation of bone formation. In vitro studies demonstrated that b-TCP/CS with MSCs of the ALP activity and the expression of osteogenic markers was higher than CS. In vivo, no bone formation was observed in CS, but newly bone formation was observed around â-TCP granules of b-TCP/CS. These results suggest that b-TCP/CS composites enhance the osteogenic differentiation of MSCs and new bone formation.

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Although it has been known that amelogenin gene is expressed in ameloblastoma, the precise expression pattern of X and Y amelogenin genes (AMGX, AMGY) in this tumor has not yet identified. In this study, we analyzed amelogenin gene expression in 19 samples (9 male, 10 female) of oral ameloblastomas by RT-PCR and detect the chromosomal origin of amelogenin mRNA by restriction enzyme digestion of the RT-PCR product. All tumor samples expressed amelogenin mRNA. We could detect increased level of AMGY expression in all male samples, higher than that of AMEX. It is an interesting finding as in normal male tooth development, the expression of AMGY is very much lower than that of AMGX. We postulate that epigenetic change of sex chromosomes may have some correlations with tumorigenesis of ameloblastoma. We also discuss the other possible mechanisms and points for future studies on this the change in expression pattern.

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Destruction of basement membrane is an important element in invasion of cancer cells. Type IV collagen, the major component of basement membrane has six distinct α chains. In this study, we investigated the localization of six α chains and matrix metalloproteinases (MMPs) in oral squamous cell carcinoma immunohistochemically. In well differentiated squamous cell carcinoma, the localization of α chains showed various patterns. α1 (IV), α2 (IV), α5 (IV) and α6 (IV) chains were stained in almost all basement membranes in the central of cancer. Unique staining with only α5 (IV) and α6 (IV) chains was also observed. In the invasive point of cancer, all a chains mainly became negative, but MMP-2 and MMP-9 were stained strongly. In poorly differentiated squamous cell carcinoma, both a chains and MMPs were not stained. Furthermore, we examined the correlation between distribution of α1 chain and invasive pattern of cancer. We found that the disappearance of α chains correlated closely with invasive activity of cancer.

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In 1999, Mundy et al. has indicated that statins, drugs widely used for lowering serum cholesterol, stimulate bone formation in rodents and increase bone morphogenetic protein (BMP)-2 expression in vitro. However, the other growth factors except for BMP-2 and the effects of simvastatin, one of statins, on periodontal tissues have not been shown yet. The purpose of this study was to investigate the possibility of statins as a new effective agent for periodontal regeneration using luciferase reporter gene assay and reverse transcription-polymerase chain reaction (RT-PCR), and the alkaline phosphatase (ALP) activity in human periodontal ligament (HPDL) cells. The results showed that simvastatin induced not only BMP-2 but also transforming growth factor-β1 (TGF-β1) in HPDL cells and human osteoblastic cells (NHOst). To examine whether the TGF-â1 activity was related with productions of the cholesterol biosynthetic pathway, HPDL cells were treated with simvastatin in the presence or absence of mevalonic acid. The TGF-β1 induction was caused by the inhibition of cholesterol biosynthetic pathway. The differentiation study showed that TGF-β1 increased the ALP activity, but BMP-2 decreased the ALP activity in HPDL cells, even in the presence of TGF-β1. The effect of simvastatin is similar to that for BMP-2 with TGF-β1. The above in vitro findings suggest that simvastatin may be effective for periodontal regeneration as new therapeutic agents to induce the regenerative factors such as TGF-β1 and BMP-2.

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Tooth-shaped titanium implants were placed into a tooth socket with adhering periodontal ligament after extraction to examine the regeneration of periodontal tissues from remaining periodontal ligament cells. The extraction forces of the implants were measured with a materials testing machine. The mechanical strength of the peri-implant ligament increased markedly from 14 (25% of control) to 28 (68% of control) days. The implants and surrounding tissues were observed morphologically. The result showed that cementum-like hard tissues were formed on the surface of the titanium implants and there were many collagen fiber bundles between the cementum-like tissues and alveolar bone at 21 and 28 days. These findings suggest that placement of an implant into a socket with periodontal ligament leads to formation of new cementum-like hard tissues with functionally-oriented collagen bundles and development of adequate mechanical strength.

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The gingival epithelium is the physiologically important interface between the bacterially colonized gingival sulcus and periodontal soft and mineralized connective tissues requiring protection from exposure to bacteria and their products. However, the molecules comprising the gingival epithelial cell junction remain poorly characterized. Thus, the aim of the present study was to characterize the desmosome-associating proteins (desmoglein 1 and 3), desmosome-associating cytoskeleton (keratins), and tight junction-associating protein (claudin-1) within the oral gingival epithelium (OGE), sulcular epithelium (SE), and junctional epithelium (JE). Gingival epithelia excised at therapeutic flap surgery from patients with periodontitis were used to examine expression of adhesion molecules by immunofluorescence. In the OGE and SE, but not JE, desmoglein 1 was more abundant in the cell-cell contact sites of the upper than the suprabasal layer, while desmoglein 3 and desmoplakin were present in the cell-cell contact sites in all layers of the JE as well as the OGE and SE. Keratin 14 and 19, but not keratin 13 and 4, were present in the JE. Claudin-1 was expressed only in the intermediate layers in the uppermost flat layers in the OGE. These data indicated that the JE contained only few desmosomes composed of desmoglein 3. Thus, it is thought that the anchoring junction connecting JE cells is not firm, causing widened intercellular spaces in the JE. In contrast, the OGE, which has tight junctions, functions as a barrier.

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The purpose of this study is to evaluate the combined effects of xylitol and low concentrations of fluoride on the promotion of remineralization of human enamel. Demineralized enamel blocks were immersed in remineralizing solutions containing 10% xylitol and various concentrations of fluoride (0-1.2ppm). The remineralizing solution containing xylitol and fluoride was found to promote remineralization between 14 and 15 degrees of saturation with respect to fluoroapatite. Although both fluoride and xylitol are thought to promote remineralization, from this study, it can be suggested that for effective remineralization, the degree of saturation with respect to fluoroapatite should also be considered.

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We developed the CO₂ incubator (Fig.1) which can emit specific wavelength (7 to 12 υm) of far-infrared ray (FIR), which range was regarded to have strong effect to living body, and had been analyzing the effect of specific FIR in radiated osteoblasts. The results suggested that specific FIR inhibited the proliferation and promoted the differentiation of osteoblastic MC3T3-E1 cells. In the present study, the gene expression in MC3T3-E1 cell affected by specific FIR was analyzed. MC3T3-E1 cells were exposed to full time specific FIR and total mRNA were analyzed by using Mouse oligo microarray (Agilent technologies) on day 3 of differentiation. Data filtering and cluster analysis were done by Genespring (Silicon Genetics). The results suggested that most important genes belonged to the control systems for transcription and, cell-cell signaling and growth affected by specific FIR.
Still more, it was found that the DEAD related system and Homeobox related system were important for transcription, and interferon related system, thyroid hormone related system, and fibroblast growth hormone related system, platelet-derived growth factor related system and interleukin related system were important for cell-cell signaling and growth by our developed profiling system of genes in specific FIR radiation.

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We examined the effect of the inflammatory mediator interleukin-1α (IL-1α) on the expression of macrophage colony-stimulating factor (M-CSF), osteoprotegerin (OPG), and prostaglandin E₂ (PGE₂) in rat osteoblasts, and the indirect effect of IL-1α on the formation of osteoclast-like cells. The expression of M-CSF and OPG were estimated by determining protein levels using Western blot analysis. PGE₂ expression was determined using ELISA. The formation of osteoclast-like cells was estimated using tartrate-resistant acid phosphatase (TRAP) staining of osteoclast precursors in culture with conditioned medium from IL-1α-treated osteoblasts and the soluble receptor activator of NF-κB ligand (RANKL). M-CSF and PGE₂ expression in osteoblasts increased markedly in cells cultured with IL-1α, whereas OPG expression decreased. The conditioned medium containing M-CSF and PGE₂ produced by IL-1α-treated osteoblasts and soluble RANKL increased the TRAP staining of osteoclast precursors. These results suggest that IL-1α stimulated the formation of osteoclast-like cells via an increase in M-CSF and PGE₂ production, and a decrease in OPG production by osteoblasts.

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It has not been determined the best scaffold-structure for bone engineering. Because of this, we compared Honeycomb porous structure (HPS) and Interconnected porous structure (IPS) with or without KUSA/A1 cells implanted in mice. The transplants were subjected to radiological and histological examinations after 1,2,4 and 8 weeks of implantation.
KUSA/A1 cells alone showed small islands of new bone. Both scaffolds alone did not reveal any bone induction. KUSA/A1-HPS presented the scaffold partially filled with new bone. In contrast, KUSA/A1-IPS showed the whole scaffold filled with new bone. Our results indicated that cotton structure plays an important role in carrying the cells giving the precise size, shape and comfortable environment.

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The present study was undertaken to determine the feasibility of using primary stability as a predictor of implant success the short-term clinical result of treatment. Methods: This study included 32 patients, in whom a total of 80 implants were placed, 34 in maxillary sites and 46 in mandibular sites. Who were partially edentulous. From May 2001 to June 2004. All implants were immediately loaded in partially edentulous patients. Then, Within 2 hours providing support for fixed provisional prosthesis and noble-metal-ceremic crowns were completed with in 3 months. All patients were followed up by 1.3.6.12 months and after the patients were checked every 6 months. Results: There were no surgical complications. A total of 80 implants were loaded immediately, From May 2001 to June 2004, No implants were lost during follow-up (range 5-36 months, mean of 19 months), no infections, nerve or sinus damages or other accidents occurred. No implants exhibited peri-implant radiolucencies. Moreover, immediate loading seems to increase the ossification of the alveolar bone around endosseous implants. Patients were satisfied with the treatment. Discussion: Clinical research has shown that immediate loading is a viable treatment modality. The favorable success rate reported in this study for rough-surfaced implants suggests that adherence to a protocol, an important parameter of which is primary stability above 32 cm, can lead to osseointegration. Conclusion: The results of this limited investigation suggest that patients who are partially edentulous may be immediately restorations, Provided that the dental implants are adequetely stable immediately after their surgical placement. The experience described in this study indicate that immediate loading with restorations using appropriate surgical and restorative techniques with one-stage JIAD(KOM) implant system can predicate the partially edentulous mandible in some cases. Further study is needed to determine the long-term result of immediately loaded implants.

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Background: Immediate implant function means great benefits for patients and therapists because treatment time and cost can be substantially reduced. The immediate-function JIAD(KOM) implant system have become an accepted alternative for fixed restorations in partial edentulous, based on documented high success rates. Countinuous development is ongoing to fine simple protocols for their use. Purpose: The purpose of resent study was to develop and document a simple, safe and effective surgical and prosthetic protocol for immediate function (within 2 hours) of JIAD(KOM) implant system supporting fixed prostheses in partially edentulous patients. Materials and Methods: This retrospective clinical study included 7 patients with 16 nature teeth by immediately loaded implants, placed in the all region, supporting fixed complete-arch jaws. 12 implants in 5 patients were placed in fresh extraction sites. The goal with the preparation and no mucosal incision and insertion technique was to achieve good primary implant stability and a minimum implant insertion torque of 30 Ncm before the implant was completely seated. The occlusion was adjusted to eliminate direct contact with the provisional prostheses. After 3 months, the patients received their permanent prostheses. All patients were followed for 1 year. Results: There were no implant losses in all sites. Conclusions: this therapeutic approach simplifies patient care without apparent additional risk.

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Enamel covers the dentin in mammalian teeth. It is believed that the enamel structure reflects the function of teeth, since the enamel structure is different depending on an animal's feeding habits. Tooth germ transplantation is a popular method for developmental and tissue engineering research. However, there is little information about the structure of the enamel of transplanted tooth germ, although tooth structure, especially enamel structure, is very important for the function of teeth. In this study, the enamel structure of E13.5 mouse mandible first molars transplanted into the kidney capsule was observed by scanning electron microscopy. Many part of the tooth crown are formed at transplantation 7 day. Although enamel and dentin were observed at the cusp portion, hard tissue was not formed at the cervical portion. The enamel prisms were observed at day 21 after transplantation. The enamel was divided into three layers according to the running pattern of the enamel prisms as normal tooth germ in vivo. However, the width of the various layers was different. It seems likely that the microenvironment surrounding tooth germ may play an important role in determining the structure of the enamel, since normal tooth germ grows in the calcified alveolar bone according as development.

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Although carcinogenesis of oral squamous cell carcinoma (OSCC) have been studied by many investigators in the past decade, the data about its molecular mechanism remain fragmented. The objective of the present study was to investigate the expression of a signaling molecule of TGF-β pathway, Smad4 in OSCC in comparison with normal oral mucosa. The expression of Smad4 in tissue samples of OSCC and oral normal mucosa was studied by means of immunohistochemical technique. We also compared the expression of Smad4 protein in SCC cell lines and normal oral keratinocytes by Western blot analysis. The rate of Smad4 expression in OSCC tissue samples was only 60% while 82% in tissue samples of normal oral mucosa. A reduction of Smad4 expression was clearly shown in all SCC cell lines as compared with normal oral keratinocytes. These findings indicate that the aberration of TGF-β pathway as evidenced by a reduction or deletion of Smad4 expression may promote carcinogenesis of OSCC.

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We evaluated the efficacy of honeycomb scaffold combined with KUSA/A1 cells in vivo. The transplants were subjected to radiographical, histological and immunohistochemical examinations after 2 and 4 weeks of implantation. KUSA/A1 cells alone showed small nests of bone formation. Whereas, KUSA/A1-Atelocollagen revealed abundant new bone formation. We also determined the immunolocalization of type I collagen, CD34, Osteocalcin, and PCNA in this newly formed bone. Our results indicated that collagen scaffold plays an important role allowing vessel formation and cell anchorage especially through the proliferation and differentiation process in a confined space. This study can possible enhances existing therapeutic applications.

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Cbfa1 (Runx2) is a well recognized factor for osteoblast differentiation. However its role during odontogenesis is not well known. We examined the morphogenesis of tooth and gene expression of matrix protein in Cbfa1-knockout mice at ed 17.5 and day 0 of birth and compared them with mandible bone development. Incisor tooth germ showed morphological and functional differentiation of odontoblasts with expression of osteopontin and osteocalcin, whereas the mandible bone-forming site displayed lack of osteoblastic differentiation, and absence of osteopontin and osteocalcin expression. Stage-specific and cytodifferentiation differences demonstrated: incisor tooth germ progressed to the bell stage, whereas molar tooth germ showed maturational arrest at bud to cap stage. Present findings suggest that 1. Cbfa1 is associated with morphogenesis of teeth and matrix protein gene expression, 2. Compared to the incisor tooth germ, the molar tooth germ is more strongly subjected to control by Cbfa1, and 3. In Cbfa1-knockout mice, the odontoblast-like cells in the incisor and the spindle cells in the mandible forming region showed different patterns of gene expression of matrix proteins which are common to both teeth and bones.

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Tumor suppressor genes are defined as genetic elements whose loss or mutational inactivation allows cells to display one or more phenotypes of neoplastic growth. Frequent deletion in a chromosomal region suggests existence of a candidate tumor suppressor gene. We analyzed Ch2q21-37.3 region by using 17 polymorphic microsatellite markers in 39 matched oral normal and cancer tissues. Loss of heterozygosity (LOH) was detected at least one location in 36 of 39 (92%) tumor tissues. High deletions were detected at microsatellite marker locations, D2S2304 (35%), D2S111 (40%), D2S155 (35%), D2S164 (29%), D2S125 (71%) and D2S140 (39%). Three frequently deleted regions at 2q22, 2q35-36 and 2q37.3 were observed. Chromosomal 2q22-37.3 region is highly populated with genes. Several candidate tumor suppressor genes in this region including such as ING5, CASP8, CASP10, PPP1R7 and BOK are located. We are currently analyzing inactivation mutations and mRNA expressions in oral squaomus cell carcinomas.

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Identifying the tumor suppressor gene (TSG) loci by genomic studies is an important step to uncover the molecular mechanisms involved in HNSCC pathogenesis. We therefore performed comprehensive analyses on loss of heterozygosity (LOH) using a genome-wide panel of 191 microsatellite markers in 22 HNSCC samples. We found 53 markers with significantly high LOH (>30%) on 21 chromosomal arms, the highest values of those were observed on 3p, 9p, 13q, 15q, and 17p, corresponding to D3S2432 (67%), D9S921-D9S925 (67%) and GATA62F03 (86%), D13S1493 (60%), D15S211 (62%) and D17S1353 (88%), respectively. Fifteen hot spots of LOH were defined in 13 chromosomal arms reported previously in HNSCCs. Furthermore, we identified 5 novel hot spots of LOH on 3 chromosomal arms in HNSCC at 2q33 (D2S1384), 2q37 (D2S125), 8q12-13 (D8S1136), 8q24 (D8S1128) and 15q21 (D15S211). In conclusion, our comprehensive allelotype analyses have unveiled and confirmed a total of 20 possible TSG loci that could be involved in the development of HNSCC. These results provide useful clues for identification of putative TSGs involved in HNSCC by fine mapping of the suspected regions.

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Destruction of basement membrane is an important element in invasion of cancer cells. Type IV collagen, the major component of basement membrane, has six distinct α chains. Matrix metalloproteinases (MMPs) are enzymes that resolve extracellular matrix. Oral squamous cell carcinoma is occurred after precancerous lesions, epithelial dysplasia and carcinoma in situ. We investigated localization of six α chains and MMPs in normal oral mucosal tissue, precancerous lesions, early squamous cell carcinoma immunohistochemically. In normal oral mucosal tissue and epithelial dysplasia, α1 (IV), α2 (IV), α5 (IV) and α6 (IV) chains were detected continuously along basement membrane. In carcinoma in situ and early squamous cell carcinoma, either α5 (IV) and α6 (IV) chains or all α chains were not stained. In contrast, MMP-2 and MMP-9 that are members of type IV collagenase were stained at the parts of disappearance of α chains. This study suggested that the disappearance of α chains is an important element in carcinogenesis of oral squamous cell carcinoma.

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Bone morphogenic protein (BMP) induces ectopic bone. In that process, there are some tissue-specific collagens (type I, II and X) in osteocartilagenous matrix. And these types of collagen are also observed in the process of ossification in condylar cartilage. We searched for the localization of collagen gene expression in ectopic bone induction using rh-BMP and condylar cartilage ossification. BMP-type I collagen complex were implanted into the subcutaneous tissue of the dorsal region of ICR mice. Then we made specimens 3 days, 1week, and 2weeks after implanting. For condylar cartilage, we pick out condylar region from ICR mice, and made specimens. The probes was made from mouse type I, II and X collagen cDNA segment (kikindly provided by Dr. Ninomiya of Okayama Universy). The process of ectopic bone induction using rh-BMP was the process through the intermediary of rapidly formed cartilagenoid tissue. And there are some difference of type I, II and X collagen gene expressions between the process using rh-BMP and that of condylar cartilage. Those gene expressions imply that the ectopic hard tissue formative cells induced in early stage will take on the characters of osteoblasts and chondrocytes, and that the cells in growing cell layer in cartilagenoid tissue can differentiate into both osteoblasts and chondrocytes.

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In order to analyze the potential teratogenic mechanism of RA in secondary palate development, we established RA-induced cleft palate (CP) model by using C57BL/6J mice and performed immunohistochemical staining by using Wnt5a, β-Catenin and Bcl-2 antibodies. Higher level expression of Wnt5a was detected in mesenchymal cells of secondary palate at E13 and the expression decreased from E14 in wild type. In RA-induced CP Wnt5a decreased severely at E15 and disappeared earlier. No relative of β-catenin and Wnt5a was detected in both wide type and RA-induced CP mouse. We also found the expression of Bcl-2 located in MEE cells of RA-induced CP group was restrained in horizontal stage of palate development.

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The human heparanase gene, an endo-beta-D-glucuronidase, has recently been cloned. It functions as an extracellular degradative enzyme that cleaves heparan sulfate proteoglycans, and acts as a critical modulator of tumor metastasis and angiogenesis. Heparanase RNA probe and monoclonal anti-heparanase antibodies were used to examine the expression of heparanase mRNA gene and protein in epithelial dysplasia, carcinoma-in-situ and/or microinvasive carcinoma and oral squamous cell carcinoma. Strong signal and expression of both gene and protein were detected in epithelium progressing from dysplasia to invasive carcinoma. Carcinomatous cells at the tumor invasive front showed the highest levels of heparanase mRNA gene and protein. These results suggest that heparanase plays an important role during oral cancer development and progression, and this may have both prognostic and therapeutic implications.

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SAPHO syndrome is characterized by bone-inflammation with or without skin lesions. We reported about clear effect of oral-treatments for skin lesion of palmoplantar pusturosis. This time, for a first investigation into a relation between oral diseases and pathogenesis of SAPHO syndrome, we made a clinical study for oral-treatments on 12 patients of SAPHO syndrome with palmoplantar pusturosis and biomedical research on trace elements in blood. Dental treatments(treatment for dental chronic focuses, dental metal removal by patch test) were done for 12 patients of SAPHO sindrome with skin, bone and joint symptoms. By the dental treatments, the skin lesion had been cured or decreased remarkably in all cases, and pain of bone and joints had been cured in all cases. The blood samples from 7 patients with SAPHO Syndrome were analyzed for trace metals. The analyzed trace metals were serum zinc serum copper serum iron blood selenium and blood mercury. The serum copper level was significantly high, the serum zinc level was significantly low and the blood selenium level was significant low than healthy control. The other trace metals in the blood showed no remarkable change. These result suggests a possibility intra-oral-focus, dental-metals and trace metals has some relation to pathogenesis of SAPHO syndrome.

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