Connective tissue reaction to white and gray MTA mixed with distilled water or chlorhexidine in rats

The purpose of this study was to compare the histocompatibility of white [WMTA] and gray [GMTA] mineral trioxide aggregate mixed with 0.12% chlorhexidine [CHX] and distilled water [DW] in subcutaneous connective tissues of rats. The freshly mixed WMTA and GMTA with CHX or DW were inserted in polyethylene tubes and implanted into dorsal subcutaneous connective tissue of 50 Wistar Albino rats; tissue biopsies were collected and were then examined histologically 7, 15, 30, 60 and 90 days after the implantation procedure. The histology results were scored from 1-4; score 4 was considered as the worst finding. Data were analyzed using one-way ANOVA tests. All experimented materials were tolerated well by the connective tissues after 90- day evaluation, except for the WMTA/CHX group that had significantly more mean inflammatory scores [P<0.001]. There was a statistically significant difference in the mean inflammation grades between experimental groups in each interval [P<0.001]. After 90 days, GMTA/CHX group had the lowest inflammatory score. Although adding CHX to WMTA produces significantly higher inflammatory response, it seems a suitable substitute for DW in combination with GMTA. Further research is necessary to recommend this mixture for clinical use

Comparison of apical microleakage using Ni-Ti with stainless steel finger spreaders

The purpose of this in vitro study was to compare apical microleakage after obturation with Nickel-Titanium [NiTi] compared to Stainless Steel [SS] finger spreaders. Eighty straight single-rooted human teeth were instrumented using step-back technique. The specimens were randomly divided into four groups. The two experimental groups [n=30] and the negative control group [n=10] were obturated by lateral condensation technique with Ariadent gutta-percha and AH26 sealer. The roots in the positive control group [n=10] were instrumented but not obturated. In one group, SS and in another group NiTi spreaders were used. Microleakage evaluation was conducted using dye penetration method t-test was used for statistical analysis. The results showed statistically significant differences between NiTi and SS groups [P=0.022], with the greatest dye penetration in SS group and the least in NiTi group. According to the results of the present study using NiTi spreader decrease apical microleakage in endodontically treated teeth

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