Endocrine-disrupting chemicals have been defined as exogenous agents that interfere with the synthesis, secretion, transport, binding, action or elimination of natural hormones in the body. The following parameters were studied using Bisphenol A (BPA): cell adhesion, cell proliferation, the expression of the related proteins, the level of estrogen receptors (ESR) and aromatase (CYP19). ESR correlates with the estrogen-like action, and Aromatase is the steroid metabolic enzyme that physiologically converts androgen to estrogen. It was shown in this study that the 10-3 M BPA treatment of epithelial cells was lethal from the results of cell adhesion and cell proliferation tests. In the 10-4 M BPA-treated 24-hour culture group, cell adhesion was about 80% that of the control group. There was no difference in adherent cell population and cell morphology in 10-5 M BPA adherent cells. However, afterwards the cell proliferation rate was significantly suppressed in comparison with the control group, and in the seventh culture, the proliferation rate decreased 60% in comparison with that of the control group. Concerning the expression of adhesion-related proteins, no difference in the expression level was recognized. The CYP19 gene expression increased by activation of ESR-1 and ESR-2 in 10-6 M and 10-7 M BPA treatment at 48 h, respectively it is supposed that the estrogen synthesis from androgens was promoted. In addition, gene expressions of ESR-1 and ESR-2 were induced after 72 h. These data suggest that BSA of low concentration may have an influence on epithelial cells.
The occurrence of resorption of the dental root is used to determine the success or failure of tooth transplantation. Tooth strage is most important factor which influences are considered success or failure. The genetic changes of periodontal ligament cells, which play an important role in the success of replantation and transplantation of preserved teeth, were investigated using real time RTPCR and cCDNA microarray. It was predicted that there might be a difference between the degree of damage to the cells in the cryopreservation group and the controlled freezing point storage (CFPS) group, and independently functioning gene clusters such as the stress reaction relation gene, apoptosis relation gene, cell death relation gene, and cell cycle relation gene were noticed. The number of genes in which the expression level was up-regulated in the CFPS group in comparison with the cryopreservation group in either gene cluster, and the number of genes down-regulated also decreased. In the low-temperature preservation, though it was considered to be one of the environmental factors which cause gene alteration, the gene expression of the gene related to the life-and-death of the cell and that related to the cell cycle decreased in comparison with cryopreservation in which CFPS. Based on the above findings, we can conclude that the CFPS method is very effective as a storage method of the cell, and it was indicated that this method has the possibility of being applied clinically.
The purpose of this study was to compare the area number density of dentinal tubules in human and bovine coronal dentin. Six human teeth and six bovine teeth were used in this study. The number of dentinal tubules per mm2 was measured in human and bovine coronal dentin using scanning electron microscopy. The mean density of dentinal tubules in human dentin was 27,838±6,700 dentinal tubules per mm2 and in bovine dentin was 31,011±1,679 dentinal tubules per mm2. These values were compared statistically by one-way ANOVA and Fisher's PLSD tests. There was no significant difference between dentinal tubule densities in human and bovine coronal dentin. Human and bovine dentins were structurally similar as observed by scanning electron microscopy.
To simplify the clinical handling of the dentin bonding procedures, one-step dentin adhesives have been developed though the efficacy of these systems has not been consistently clarified. The aim of this study was to investigate the effect of nine commercial one-step bonding system by measuring the contraction gap width of the resin composite in a dentin cavity. Nine commercial onestep bonding systems, (Absolute, Absolute 2, Bond Force, Fluoro Bond Shake One, G-Bond, i-bond, One-up Bond F plus, Prompt L-pop and S3 bond) were used. A cylindrical cavity, 3 mm in diameter and 1.5 mm deep, was prepared in the dentin of extracted human tooth. The one-step adhesives were applied in the cavity according to the manufacturers' instructions and a commercial resin composite (Palfique Estelite, Tokuyama, Japan) was filled. The marginal adaptation of resin composite was inspected under a light microscope and possible contraction gap width was measured. The gap values were statistically analyzed by Fisher's PLSD(p<0.05). For the positive control, the dentin cavity was conditioned with E-Lize Conditioner and primed with E-Lize Primer.Then a commercial dentin bonding agent (Clearfil Photo Bond, Kuraray, Japan) was applied prior to the resin composite filling.Complete marginal adaptation of composite was observed only in the control group. The gap values of tested dentin bonding systems were statically classified into two groups. Three one-step bonding systems (Prompt L-pop, Absolute and Fluoro Bond Shake One) exhibited significantly inferior marginal adaptation compared to that of other seven groups.
The junctional epithelium (JE) is at the front site of defense against microorganisms. However, the immunological characteristics of the JE and migrating cells within the JE are unclear. We examined the immunohistochemical expression of cell adhesion molecules(CAMs) on the JE and the cell surface markers on the migrating cells. In gingival epithelium, only the JE expressed intercellular adhesion molecule-1 (ICAM-1). Three distinct layers in the JE could be identified by the intensities of ICAM-1 expression; both side layers (ICAM-1high) facing the tooth surface or oral epithelium (OE), and the middle layer (ICAM-1low). Lymphocyte-function associated antigen-1 (LFA-1+) cells were uniformly distributed in the JE. Gr-1+ cells were located at both side layers, while CD3+ cells were detected in the middle layer. Most of the CD3+ cells expressed a T cell receptor γδ (TCRγδ). These results indicated that JE expressed ICAM-1 constitutively, that the interaction of LFA-1 and ICAM-1 might be a key role for the migration of cells into the JE, and that most of migrating cells were neutrophils and TCRγδ+ T cells.