Histo-blood group antigen expression and proliferative activity of fibroblasts treated with dental monomers.

The present work is focused on examining the effect of the structurally similar dental monomers bis-GA and bis-GMA on the expression of histo-blood group antigens (HBGAs) in comparison with fibroblast vitality and proliferation. The fibroblast cell line McCoy-Plovdiv was cultivated in a serum-free medium and was treated with both monomers. Cell vitality was measured by the crystal violet test. Mitotic index and cell morphology were assessed. An immunocytochemical technique was applied to follow the expression of proliferative antigens PCNA and Ki-67 and of HBGA. The expression level of HBGA was measured by an improved pixel selection algorithm with proprietary software. The lowest concentration of 2.5 micromol/L did not significantly affect morphology, vitality, or proliferation activity. Interestingly, the quantitative analysis revealed augmented expression of HBGA B at 2.5 micromol/L. The higher concentrations of the dental monomers reduced cell vitality and mitotic indices and altered proliferative antigen expression. Bis-GA proved to be more toxic than bis-GMA and caused more prominent alterations including greater enhancement of HBGA B expression. We present novel evidence for altered expression of proliferative antigens and enhanced expression of HBGA B in fibroblasts treated with dental monomers bis-GA and bis-GMA suggesting that these substances affect cell morphology, proliferative activity, and antigenic profile.

Electrometric determination of the working length of root canals by means of Apex locator.

AIM: To evaluate an apex locator in determining the working length of root canals and detecting micro-communications with the pulp chamber. METHODS: The apparatus was tested on 21 patients, aged 18 - 70, who received endodontic treatment of 34 teeth with 45 root canals. The apparatus was used in compliance with the instructions of the manufacturer. The precision of the instrument was determined by a radiograph of the tooth with a file inserted in it at a depth equal to the length determined with the Apex locator. The obtained results were divided into three groups: canals determined as longer; canals in which the outline of the instrument was close to the roentgenologic apex; and canals determined as shorter. CONCLUSION: The average deviation from the roentgenologic apex was 1.17 mm, which is, in fact, the area of the physiological apex opening - the ideal limits for treatment and obturation. The apparatus can be successfully used to make differential diagnosis is useful of deep caries with pulpitis chronica ulcerosa. It is ergonomic and easy to use.