Comparative cytotoxicity of five root canal sealers on cultured human periodontal ligament fibroblasts.

AIM: To evaluate the cytotoxicity of current root canal sealers to periodontal ligament (PDL) fibroblasts. METHODOLOGY: Five root canal sealers (Canals, Canals-N, Topseal, Sealapex, Tubliseal) were prepared and placed into transwells. After initial setting for 1 h, the transwells with sealers were placed into cultured PDL fibroblasts. They were cultured for further 3 or 18 h. Morphological changes were observed. Cell viability was estimated by 3-(4,5-dimethyl-thiazol-2-yl)-2,5- diphenyl-tetrazolium bromide (MTT) assay. RESULTS: Marked retraction and death of PDL fibroblasts were observed after exposure to Canals or Topseal for 3 h. A 3-h exposure of PDL fibroblasts to Tubliseal stimulated MTT reduction. Canals-N showed little cytotoxicity even after an exposure of 18 h. CONCLUSION: Canals was the most toxic sealer, followed by Topseal. Sealapex and Tubliseal had comparable and moderate cytotoxicity to PDL fibroblasts, whereas Canals-N showed little cytotoxicity. Exposure to Tubliseal may modulate MTT reduction in PDL fibroblasts. Canals-N had good biocompatibility.

A predictive study on the role and function of the dental hygienist in Taiwan.

OBJECTIVES: The purpose of this study was to achieve a consensus on the work roles and scope of practice of dental hygienists in Taiwan and to rank the results according to their importance. METHODS: A modified Delphi technique was used to enquire how experts view their role and function as a dental hygienist in Taiwan. Three groups of 105 experts (dentists, officials and scholars) were surveyed. Responses were analysed using qualitative statistics. RESULTS: Fifty-one topics, which were included in the categories of the research agenda, were identified through the first phase of the study. The return rate of 87.62% and 68.48% was achieved from the two rounds of surveys. Afterwards, a consensus was reached on 38 out of the 51 topics. In the aspect of service, the most desired roles and functions were those of a friendly receptionist and of an employee effective in scheduling appointments. In the aspect of administration, the most important roles and functions were billing of health insurance, and book keeping on payments, as well as administering materials. In the aspects of technical efficiency, dental hygienists were most frequently seen as serving in four- or six-handed assisting and in infection control. In the area of oral health, an oral health educator and an oral health promoter were viewed as having the most important roles and functions. CONCLUSIONS: The experts concluded that the role and function of a dental hygienist should shift from a patient treatment orientation to that of an oral health promoter. The role expectations need to change to reflect what hygienists actually learn and do.

Interleukin-8 secretion by cultured oral epidermoid carcinoma cells induced with nicotine and/or arecoline treatments.

Interleukin-8 (IL-8) is one of the multifunctional cytokines that can play a role on immune and inflammatory activities. Other in vitro observations indicated that IL-8 is a growth factor for keratinocytes. However, as the role of IL-8 in oral cancer cells is unclear, this study is thus designed to examine IL-8 secretion in cultured oral epidermoid carcinoma KB CCL17 cells treated with nicotine and/or arecoline. The cultures were treated with nicotine (1 or 100 microM) and arecoline (1 or 100 microM), alone or both, for 72 hrs. Enzyme-linked immunosorbent assay (ELISA) was used to examine IL-8 concentrations in culture supernatants. A repeated measure analysis of variance was used to identify differences among the treatments. Nicotine and arecoline, single or combined treatment, increased IL-8 secretion in KB CCL17 cells. When monoclonal 1 microgram/ml of antibody was added against IL-1 alpha or IL-1 beta in the treatment, IL-8 concentration significantly decreased compared with the non-added one. Exposure of cells to antibody against IL-1 alpha or IL-1 beta showed no significant increase in cell growth as compared with the control (medium alone). However, incubation of cells for 72 hrs in the presence of nicotine and/or arecoline treatments and antibody against IL-1 alpha or IL-1 beta significantly increased cell growth as compared with the antibody free one. It was concluded that IL-8 secretion by KB CCL17 cells may be partially mediated by IL-1 which could inhibit the KB CCL17 cell growth. Thus, IL-8 may be a vital participant in the cascade of interacting cytokines during smoking and areca quid chewing, inducing inflammation in oral cancer.

Nicotine- and arecoline-induced interleukin-1 secretion and intercellular adhesion molecular-1 expression in human oral epidermoid carcinoma cells in vitro.

The purpose was to examine interleukin (IL)-1 concentrations and intercellular adhesion molecule (ICAM)-1 expression in nicotine/arecoline-exposed oral KB CCL17 cultures. Enzyme-linked immunosorbent assay was used to quantify IL-1 concentrations in culture supernatants. A repeated-measures analysis of variance was used to identify differences among the groups. IL-1 beta concentrations increased by 2.6, 2.7 and 7.5 times those of the control in groups treated with 1 microM nicotine, arecoline or with both, respectively. IL-1 beta concentrations were more dramatically increased when the agents tested were at 100 microM concentration. Similar, although less dramatic, alterations in IL-1 alpha concentrations were observed. The fluorescence intensity of ICAM-1 (CD54) analysed by flow cytometry was also significantly increased in a dose-dependent manner when the cells were treated with nicotine and/or arecoline. Nicotine and arecoline therefore significantly increased IL-1 alpha and -1 beta secretions and the surface expression of ICAM-1 in KB CCL17 cells.