Adaptation and sealability of two contemporary obturation techniques in the absence of the dentinal smear layer

Aim The aim of this study was to evaluate the adaptation and short- and lon g-term sealability of two different thermoplastic techniques - a core carri er technique, Thermafil; and a warm vertical continuous wane of compaction technique, System B. Methodology Fifty-one mesial roots of mandibular molars with separate canal s, patent canal orifices and curvature greater than 15 degrees were cleaned and shaped with Orifice Shapers and Profile.04/.06 taper Ni-Ti rotary file s using 5.25% NaOCl and 17% REDTA to a size 30.04 taper Profile at the apex to create a continuous tapered preparation. Canals were randomly obturated with Sealapex root canal sealer and either alpha-phase gutta-percha on a p lastic Thermafil carrier, or nonstandardized beta-phase gutta-percha using the System B heat source. Proximal radiographs of roots were evaluated by t hree examiners based on established criteria for overall material adaptatio n, apical adaptation and filling material extrusion, Teeth were randomly se parated into three groups of 17 each and placed in black India ink for 10 d ays, 24 h, or after 67 days storage in Hank's Balanced Salt Solution. All r oots were demineralized and rendered transparent. Three examiners evaluated the apical leakage by the linear measurement of dye penetration under the stereo-microscope. The movement of filling material into canal irregulariti es was also evaluated. Results Both obturation techniques were not significantly different in the overall canal obturation and in the apical third adaptation (P > 0.05). Sig nificantly more filling material extrusion beyond the apex was noted with t he Thermafil technique (P < 0.001). No significant difference was found amo ngst the 67-day, 10-day and 24 h System B groups (P > 0.05). The 67-day The rmafiI group showed significantly more leakage than the 10-day and 24 h The rmfil groups. There was a significant difference in the degree of leakage b etween the 67-day Thermafil group and the 67-day System B group (P < 0.05), but not between the 10-day and 24 h groups (P > 0.05). Both obturation tec hniques produced substantial filling material movement into canal irregular ities. Conclusions It was concluded that Thermafil demonstrated more filling mater ial extrusion beyond the apex and significantly more long-term apical leaka ge.