The aim of this study was to assess the relationship between Porphyromonas gingivalis, Epstein-Barr virus (EBV) infection and reactivation in periodontitis using real-time PCR. The mean proportion of P. gingivalis cells to total bacterial cells in the saliva from EBV-positive periodontitis patients was significantly higher than that in saliva from EBV-negative patients. An EBV-positive B-cell line was used to determine whether P. gingivalis sonicate induced reactivation of EBV, using real-time PCR to measure the virus genome in the culture medium. A significant increase in EBV numbers was observed after the stimulation with P. gingivalis sonicate. These findings suggest that the interaction between EBV and P. gingivalis is bi-directional, with EBV reactivation suppressing host defenses and permitting overgrowth of P. gingivalis, and P. gingivalis having the potential to induce EBV reactivation. (J. Oral Sci. 46, 203-206, 2004)

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The ability of human mesenchymal stem cells (hMSC) to differentiate into osteoblasts was examined through the use of osteogenic induction medium (MSCOIM) cultures. hMSC first attached to the dish surface and exhibited fibroblast-like spindle shapes, and after proliferation, formed cuboidal shapes. Calcium assays and the use of von Kossa and alizarin red S staining showed that hMSC were capable of mineralization when cultured in MSCOIM. Gene expressions of Cbfa-1 and BMP-4, which are markers for osteogenic differentiation, were also increased during the hMSC differentiation into osteoblasts. When compared to albumin (Alb)-coated dishes, microscopic observation documented enhanced cell attachment and spreading when hMSC were cultured on fibronectin (FN)-coated dishes. Adherent cell numbers also exhibited a greater increase on the FN-coated dishes during earlier culture stages than that seen for the Alb-coated dishes. These findings suggest that hMSC have the capability to differentiate into osteoblasts and that FN can stimulate the attachment and spreading of the hMSC. (J. Oral Sci. 46, 207-213, 2004)

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Given the importance of sterilizing human teeth before using them in research, the effects of a 25 kGy dose of gamma radiation on the mechanical properties of enamel and its resistance to demineralization were evaluated. Thirty human teeth were sectioned longitudinally, and while one half of each tooth was irradiated, the other half was kept as a control. Abraded and unabraded enamel slabs were obtained from these halves. The surface microhardness (SMH) of abraded slabs of irradiated and non-irradiated enamel was determined to evaluate the effect of radiation on enamel structure. Further, both abraded and unabraded slabs, either irradiated or non-irradiated, were submitted to a pH-cycling model to evaluate enamel resistance to demineralization, which was quantified by mineral loss (ΔZ) using cross-sectional microhardness. The data for SMH and ΔZ were statistically analyzed by t-test and ANOVA, respectively. The difference in enamel SMH between slabs from irradiated teeth and non-irradiated teeth was not statistically significant (P > 0.05). The abraded enamel slabs showed higher values of ΔZ than unabraded enamel slabs (P < 0.05), but the irradiation effect was not statistically significant (P > 0.05). The results suggest that the medical gamma radiation dose of 25 kGy does not affect either enamel hardness or its resistance to demineralization. (J. Oral Sci. 46, 215-220, 2004)

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The aim of this study was to investigate the prevalence and psychosocial impact of enamel defects among 16-year-old school children on the island of Penang. The data were collected through a self-administered questionnaire survey and an oral examination, using the Modified Developmental Defects of Enamel Index (FDI, 1992). In all, 1024 subjects were selected using a multistage random sampling technique. About two-thirds of the sample (67.1%) had at least one tooth affected by enamel defects. Enamel opacities accounted for 85.6% of the total condition. Diffuse-type opacity predominated (63.5%). Among subjects who expressed dissatisfaction, 18.8% reported covering their mouths when smiling, 8.7% avoided going out with friends and 39.1% had consulted their dentists. About 17% of the subjects reported that their parents had complained about the color of their front teeth but only 5.7% had experienced being teased by their friends about the problem. Two-thirds of the subjects were affected by enamel defects involving at least one tooth; however, the esthetic perception and psychosocial impact of those affected were minor. (J. Oral Sci. 46, 221-226, 2004)

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The exact pathomechanism of inflammation progress and fibrosis in chronic sialadenitis is unknown. Connective tissue growth factor (CTGF), matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) have been implicated in the pathogenesis of various fibrotic conditions. These factors are thought to be essential in the regulation of extracellular matrix turnover and the development of tissue fibrosis. In the present study, the expression of CTGF, MMP-2, -3, -9, -13 and TIMP-3 was examined in chronic obstructive sialadenitis. Tissue samples of 13 patients with chronic sialadenitis of the submandibular gland associated with sialolithiasis and 4 normal tissue samples of the submandibular gland were analyzed immunohistochemically and by Western blot analysis. An intense CTGF immunoreactivity was observed in the ductal system of inflamed salivary glands, whereas in normal glands no reactivity or a very low CTGF immunoreactivity was present. Immunohistochemical studies revealed a low to strong reactivity of MMP-2, -3, -9, -13, and TIMP-3 in the ductal system, in acinar cells and in lymphomonocytic infiltrates in normal and inflamed tissues. The expression of MMP-2, -3, -9, -13, and TIMP-3 was confirmed by Western blotting in all cases. Over-expression of CTGF in chronic obstructive sialadenitis suggests that this factor may play a role in glandular fibrosis. However, the physiological role of MMP-2, -3, -9, -13, and TIMP-3 in normal glands, as well as their possible role in inflammation progress and fibrosis in chronic obstructive sialadenitis, remains to be elucidated. (J. Oral Sci. 46, 227-233, 2004)

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In this study, the bond strength between an indirect composite and a gold alloy was determined for the purpose of evaluating noble metal bonding systems. A single liquid primer designed for conditioning noble metal alloys (Infis Opaque Primer) and tri-n-butylborane-initiated adhesive resins (Super-Bond C & B), with or without the powder component, were assessed. Cast gold alloy disks (Casting Gold type IV) were air-abraded with alumina, followed by six surface preparations, and were then bonded with a light-activated composite material (New Metacolor Infis). Shear testing was performed both before and after thermocycling for evaluation of bond durability. The results showed that three primed groups improved post-thermocycling bond strengths compared to each of the corresponding unprimed groups (P < 0.01). The bond strength was reduced for all six groups by the application of thermocycling (P < 0.01). After thermocycling, the group primed with the Infis Opaque Primer material and bonded with the Super-Bond C & B resin exhibited the greatest bond strength (23.4 MPa). The Infis Opaque Primer and Super-Bond bonding system increased the post-thermocycling bond strength of the control group by a factor of approximately ten. This simple technique is applicable in the fabrication of composite veneered restorations and cone-telescope dentures. (J. Oral Sci. 46, 235-239, 2004)

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The purpose of this study was to investigate the association between periodontal conditions and electrocardiogram test results that were obtained to screen for coronary heart disease risk factors. The present study included a total of 578 subjects who underwent annual medical check-ups at the Total Health Care Center in Otsu, Shiga Prefecture, Japan. To calculate the odds ratios for the electromyography abnormalities, we performed a logistic regression analysis for the oral examination, electrocardiogram, and blood analysis data. The crude odds ratio was obtained by a logistic regression analysis of age, sex, number of missing teeth, number of filled teeth, simplified oral hygiene index, community periodontal index, and blood analysis factors and results indicated there was a statistically significant correlation with the prevalence of electrocardiogram abnormalities. However, electrocardiogram abnormalities have a strong correlation with demographic factors such as sex and age. Therefore the experimental factors representing oral status were reexamined after the odds ratios were adjusted for age and sex. As a result of this adjustment, the new odds ratios that were determined indicated that there were no correlations between the oral factors and the prevalence of electrocardiogram abnormalities. (J. Oral Sci. 46, 241-246, 2004)

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We report here a clinico-statistical study of congenital absence of the permanent canines (CAPC). Sixty-five cases (22 men and 43 women) of CAPC were found in the files of 35,927 outpatients, an incidence of 0.18%. Thirty-seven cases had single absence of the canine and 28 cases had multiple absences. There were 42 cases in the maxilla, 17 in the mandible, and 6 in both the maxilla and the mandible. In the single absence cases, there was a tendency of occurrence at the left side in the maxilla, and the right side in the mandible. There were 39 CAPC cases without absence of other permanent teeth. Several complicated dental anomalies were seen such as persistence of deciduous teeth, congenital absence of other permanent teeth, microdontia, malposition, and complete or incomplete impaction (excluding the third molars). The complication rate of other permanent tooth absences was higher in the cases with CACP in the maxilla than in the mandible. (J. Oral Sci. 46, 247-252, 2004)

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The maxillofacial region is affected by a greater number of cysts than any other part of the body. In this study, 90 odontogenic cysts were collected from 90 patients over a five-year period. Patients with radicular cysts, dentigerous cysts and odontogenic keratocysts were further analyzed with regard to age, sex and anatomical distribution. Using the histological classification of the World Health Organization, 53 cases (59%) were classified as radicular cysts, 24 (27%) as keratocysts and 13 (14%) as dentigerous cysts. Radicular cysts occurred most frequently in the anterior region of the maxilla, odontogenic keratocysts in the ramus and angular region of the mandible, and dentigerous cysts in the mandible. No recurrences were observed during the limited follow-up period. (J. Oral Sci. 46, 253-257, 2004)

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A family case of Cleidocranial Dysplasia is presented. A mother and two adolescent girls were examined. In all three cases, a radiological series was performed over the entire body. Generalized dysplasia in bones, prolonged retention of primary teeth, and delayed eruption of permanent, as well as supernumerary teeth was diagnosed. The citogenetic study with GTG band showed normal 46, XX. Bilateral audiometry in the mother demonstrated a mild to moderate hypoacustic condition. Radiological findings are presented and the importance of early diagnosis is discussed. (J. Oral Sci. 46, 259-266, 2004)

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