An in vitro comparative study of four different root canal obturation techniques on the apical seal using two different sealers

The objective of obturation in endodontic is total obliteration of the root canal system and development of a fluid-tight seal at the apical foramen. The aim of this work was to compare the apical seal of four root canal obturation techniques namely lateral condensation technique, vertical condensation technique, warm lateral condensation technique with an ultrasonically activated spreader and Thermafil, when used with two different root canals sealers. 80 extracted human maxillary anterior teeth were used in this study. All root canals were instrumented by the step back technique. Root were divided into four groups [according to the technique of obturation and each group was further subdivided into two subgroups according to the type of sealer used. Leakage evaluation was done by using clearance technique by maximum linear apical dye penetration. The results were tabulated and statistically analyzed. The obtained result showed that there was no significant difference among the four obturation techniques, regarding the apical leakage with insignificant difference between the two sealers. Vertical condensation is the most time consuming technique. Sealer extrusion occurs with all the specimens obturated by Thermafil. Clearing technique is a valuable method in evaluating apical leakage in extracted teeth

Effects of two root canal preparation techniques and two different apical sizes on bacterial count: an in vitro comparative study

The purpose of this in-vitro study was to compare the intracanal bacterial reduction produced by two instrumentation techniques and two different apical size diameters. The mesio-buccal canals of 50 extracted human mandibular first molars, experimentally infected with Enterococcus Faecalis, were prepared either by the steep-back technique, with hand K flexo-files, or by the crown-down technique using protaper Ni-Ti rotary files. Each technique was once used where apical preparation was carried till size 20, and again where apical preparation was carried till size 35. A control group of ten canals was added where no canal instrumentation was done. Only saline irrigation was used. Samples taken before and after treatment were diluted 10-folds in the wells of ELISA plates. Then aliquots of 20ul were plated onto nutrient agar and the colony forming units that were grown after 24h incubation were counted. All techniques and apical sizes significantly reduced the number of bacterial cells within the root canal [p<0.05]. There was no significant difference between the experimental group [p>0.05]. Nonetheless, all of them were significantly more effective than the control group