The comparative effectiveness and safety of three activated irrigation techniques in the isthmus area using a transparent tooth model.

AIM: To compare the effectiveness and safety of three activated irrigation techniques when removing pulp tissue from the isthmus of a transparent tooth model. The three techniques assessed were: the EndoVac (EV), passive ultrasonic irrigation (PUI) and ultrasonic wave aspiration (TUWA). Conventional syringe irrigation (CSI) was used as a control. METHODOLOGY: A transparent tooth model was created using the mesial root of an extracted mandibular first molar that had an isthmus and two independent mesial canals. An artificial 0.3-mL cylindrical chamber was created below the apical foramen. The tooth was then cleared. After preparation, the root canals were filled with fuchsine-stained bovine pulp tissue. The irrigation protocols were compared in respect of their effectiveness at removing pulp tissue from the isthmus and their safety with regard to irrigant extrusion. For all four groups, 5.25% sodium hypochlorite solution was used as the irrigant. Photographs were taken and analysed using an imaging software. A Kruskal-Wallis test was used to detect the differences between groups (statistical significance was set at P < 0.05). RESULTS: No group was associated with extrusion of irrigant beyond the apex. Significant differences were observed between the groups: TUWA was the most effective technique at removing pulp tissue from the isthmus (3.39 mm2 ; standard deviation (SD) = 0.67; range = 1.25-3.69), followed by PUI (2.16 mm2; SD = 0.38; range = 1.37-2.96), EV (0.73 mm2 ; SD = 0.14; range = 0.49-0.98) and CSI (0.27 mm2 ; SD = 0.01; range = 0.26-0.28). CONCLUSION: Ultrasonic wave aspiration was the most effective technique at removing artificial pulp tissue from the isthmus of a transparent tooth model. None of the techniques extruded irrigant.

Influence of HDV infection on clinical, biochemical and histological presentation of HBsAg positive chronic hepatitis.

In an attempt to identify some characteristics of HDV infection in the different forms of HBsAg positive chronic hepatitis (CH), we evaluated numerous clinical, biochemical and histological aspects in 203 consecutive HBsAg positive CH patients. The presence of hepatitis delta antigen (HD-Ag) in the liver tissue was the criterion used to identify HDV infection. HD-Ag was observed in none of the 7 patients with non-specific reactive hepatitis, in 14.6% of the 48 with chronic persistent hepatitis (CPH), in 36.4% of the 44 with chronic lobular hepatitis (CLH), in 36% of the 25 with mild chronic active hepatitis (CAH), in 52% of the 36 with severe CAH and in 30.2% of the 43 with inactive or moderately active cirrhosis. Compared with the 139 HD-Ag negative patients in this study, the 64 HD-Ag positive patients more frequently had severe CAH (29.7 vs. 12.2%, p less than 0.01) and less frequently CPH (10.9 vs. 29.5%, p less than 0.01). Of the 139 HD-Ag negative patients, 80 were anti-HD positive and 59 anti-HD negative. The 59 patients with no HD-Ag or anti-HD showed severe CAH less frequently than the 64 HD-Ag positive patients (6.8 vs. 29.7, p less than 0.01) and CPH more frequently (44.1 vs. 10.9, p less than 0.001). Both in CPH and CLH the presence of HD-Ag in the hepatocytes identified subgroups of patients who frequently showed high serum levels of aminotransferases and gammaglobulins and more extended areas of circumscribed lobular necrosis. HD-Ag positive CAH was characterized by a more frequent occurrence of eosinophilic degeneration of hepatocytes without peripolesis (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)