We have previously demonstrated that gingival fibroblast obtained from nifedipine reactive patients (nifedipine responder, NIFr) was found to possess higher proliferative activity than fibroblasts obtained from nifedipine non-reactive patients (nifedipine non-responder, NIFn) or normal gingival fibroblast (nifedipine non-treated gingival fibroblast) . 18α-Glycyrrhetinic acid (18α-GA), a constituent of licorice, is a good anti-proliferative agent especially on those cells whose replication rate is slow, by inhibiting the onset of progression. Thus, we examined the effect of 18α-GA to clarify whether it depresses the growth of NIFr. 18α-GA inhibited cell proliferation and G₁/S transition induced by bFGF in NIFr cells. It was also shown that cell cycle control proteins, such as pRB (ser780), pRB (ser807/811), CDK4, CDK6, CDK2, cyclin D1, and cyclin A, were down-stream targets in the growth-inhibition activity of 18α-GA in NIFr cells. In the development of nifedipine-induced gingival overgrowth, an inflammation and the cell growth of NIFr cells are important factors. Based on these findings, 18α-GA, which has anti-inflammatory effect and inhibits growth of NIFr cells, may have a positive role in nifedipine-induced gingival overgrowth therapy.

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Cytokines are messengers that play a major role in mediating cellular functions to resist external invasion such as trauma and surgical intervention by maintaining physiological homeostasis. The amount of cytokines produced changes when the human body is exposed to such external invasion, suggesting a close relationship between cytokine levels and invasion. The purpose of this study was to investigate changes in serum cytokine levels in a mouse model of shinbone fracture by determining post-fracture IL-6, IL-10, and IL-1β levels over time. Male C57BL mice, aged 8 weeks, received intraperitoneal anesthesia with pentobarbital sodium, and an artificial unilateral fracture was made in the thighs of the mice. Fractures were confirmed using plain dental x-ray films. Cardiac blood sampling was performed at 1, 3, 24, 72, and 120 hours after fracture. Collected blood was coagulated and centrifuged to obtain serum samples. Enzyme-linked immunosorbent assay (ELISA) was used to determine serum levels of IL-6, IL-10, and IL-1β. The results showed that IL-6 level in the fractured mice peaked at 3 hours after fracture and was significantly higher at 3 and 24 hours, as compared to that in the control. IL-6 levels in the fractured mice were significantly lower at 24, 72, and 120 hours after fracture than the peak level observed at 3 hours. IL-10 level also significantly increased at 3 hours after fracture, indicating that its changes over time were very similar to those of IL-6 level. No significant differences were noted for changes in IL-lβ levels at any assessment time point. These results showed that serum levels of I1-6, indicating degrees of invasion, and IL-10, an anti-inflammatory cytokine, had a similar profile of changes in time course after a shinbone fracture. These contrastive cytokines were found to be released simultaneously at the early stage after fracture, and the release was observed for a short period of time, even if no treatment was provided.

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The purpose of this study was to investigate the removability of calcium hydroxide dressed in root canals. Three types of calcium hydroxide pastes were used: Calfee paste ^®, Caicipex, ^® and Caicipex II ^®. Five single-rooted human extracted teeth were used. After removing the tooth crowns, the canals were prepared by NiTi files with 0.06 taper using the conventional method, and the roots were sectioned in the bucco-lingual direction so that repositionable root canal models could be obtained. After root canal dressing of the calcium hydroxide pastes, the root canals were irrigated by the following three methods: alternative irrigation with 1.5mL of 3% hydrogen peroxide and 1.5mL of 6 % sodium hypochlorite (NaClO), solely with 3.0mL of NaClO, or 3.0mL of NaCIO with ultrasonics. Then, the canal model assemblies were dismantled, and the images of the canal wall surfaces were taken with a digital microscope. The ratio of the area occupied by calcium hydroxide pastes to the total canal wall surface area within 3 mm from the root apex was calculated as a percentage for each canal model. Statistical analysis showed that the removability of Calfee paste ^® was the highest among the three calcium hydroxide pastes (p < 0.05) . There were no statistically significant differences among the irrigation methods used (p > 0.05) .

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The effects of tetracyclines in organotypic cocultures using human gingival epithelial cells (NDUSD-1 cells) and human periodontal ligament fibroblasts (Pelt cells) were investigated. The organotypic cocultures were treated with tetracycline (TC) or minocycline (MINO) at 10-300μM for 1 week and multilayered epithelial cells were examined by hematoxylin-eosin staining and immunohistochemistry. Treatment with TC at 30μM did not affect multilayer formation of epithelial cells, but the formation was inhibited by treatment with TC at 100μM or more. Treatment with MINO at 10μM did not affect the multilayer formation, but the formation was inhibited by treatment with MINO at 30 μM or more. These values were greater than their MIC₉₀ concentrations for periodontopathic bacteria, including Porphyromonas gingivalis, Prevotella intermedia, and Actinobacillus actinomycetemcomitans. These results suggested that topical administration of TC or MINO to the periodontal pocket at their MIC90 concentration for periodontopathic bacteria would have few adverse effects on the growth of the periodontal ligament.

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We report a 34-year-old male with a mandibular bone ameloblastoma postoperativelly, with severe MRSA infection which was isolated from the wound, gastric fluid and feces culture. The patient was successfully treated with linezolid.

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