Effect of synthetic tissue fluid on microleakage of grey and white mineral trioxide aggregate as root-end filling materials

The success of endodontic surgery has been shown to depend partly on the apical seal. Grey mineral trioxide aggregate [GMTA] produces hydroxyapatite twice as often as white mineral trioxide aggregate [WMTA] when suspended in a phosphate buffered saline [PBS] solution. The aim of this in vitro study was to compare the microleakage phenomenon of gray and white mineral trioxide aggregates as root-end filling materials after immersion in synthetic tissue fluid [STF]. 55 single-rooted extracted maxillary anterior human teeth were divided into two experimental groups of 20 teeth each, plus 3 groups of 5 teeth each as two negative and one positive control groups. The root canals were cleaned, shaped, and laterally compacted with gutta-percha. The root ends were resected and 3 mm deep cavities were prepared. The root-end preparations were filled with GMTA or WMTA in the experimental groups. Leakage was determined using a dye penetration method. Data were analysed using analysis of variance [ANOVA] at the 0.05 level of significance. Results: The mean dye leakage was 0.40 +/- 0.1 mm for GMTA and 0.50 +/- 0.1 mm for WMTA groups, respectively. There was no significant difference between the two experimental groups [P = 0.14]. Despite the different properties and behaviours of GMTA and WMTA in STF, there were no significant differences in microleakage when using GMTA or WMTA

comparative scanning electron microscope investigation of cleanliness of root canals using hand K-Flexofiles, rotary RaCe and K3 instruments

The most important aims of root canal preparation are the removal of vital pulp tissue, remaining necrotic debris and infected dentin, eliminating the bulk of bacteria present in the root canal system. The aim of this study was to compare the cleaning efficacy of hand K-Flexofiles and rotary RaCe and K3 instruments in root canal preparation. A total of 60 single rooted teeth with maximum curvature of <20§ were selected and divided into three groups of 20 teeth each. Canals were prepared with KFlexofiles, K3 and RaCe instruments using crown down preparation technique, up to size #30. After instrumentation, the root canals were flushed with 5 mL of 2.5% NaOCl solution. The amount of debris and smear layer was quantified on the basis of Hulsmann method using a scanning electron microscope. The data were statistically analyzed with one-way ANOVA test at a significance level of P<0.05. None of the three groups achieved completely debrided root canals.. In general, KFlexofiles were able to achieve cleaner canals compared to K3 and RaCe instruments [P<0.05]. There were no significant differences between three groups in smear layer removal throughout the root canal walls [P<0.05]. K-Flexofiles group had less remained debris when compared to K3 and RaCe instruments