Preparations of apical cavities in resected root ends using rotary burs, with and without citric acid rinse, and ultrasonic tips were compared based on the presence or absence of superficial debris and smear layer. Three groups of 20 extracted teeth each were prepared as follows; I, a size 010 round bur was used to prepare an apical cavity 2-3 mm down the long axis of the root; II, treatment as per group I followed by a 60-s rinse with a solution of 10:3 (10% citric acid, 3% Fe2Cl3); and III, an ultrasonic retrotip was used to prepare a 2-3 mm deep apical cavity. Roots were grooved longitudinally, split and prepared for SEM analysis at x100 and x780 magnification. Examiners were calibrated to a standardized grading system. Extensive statistical analyses indicated statistically significant differences within and among the groups (P < 0.05). Root-end preparation with a bur created a heavy smear layer at all levels of the preparation. This layer was partially removed during ultrasonic preparation in the apical two-thirds. A greater removal of the smear layer was achieved with the citric acid rinse (P < 0.05). Coronally, root-end preparations were contaminated with moderate to heavy amounts of debris with all techniques.

Summary Adaptation and placement of alpha‐phase gutta‐percha delivered with a plastic core‐carrier, Thermafil, was compared to the lateral condensation of gutta‐percha in a specific tooth model. Fifty‐one mandibular molar roots with separate canals, patent canal orifices and curvatures greater than 15 degrees were cleaned and shaped with K‐files and 2.5% sodium hypochlorite to a size 30 at the apex, and flared with Hedstrom flies to create a continuously tapering funnel preparation. Canals were randomly obturated with Sealapex root canal sealer and either alpha‐phase gutta‐percha on a plastic Thermafil carrier, or standard beta‐phase gutta‐percha with lateral condensation. Roots were radiographed from the proximal and evaluated by three examiners, based on established criteria for overall material adaptation, apical adaptation, and filling material extrusion. Thermafil provided a statistically significant better over‐alt canal obturation (P < 0.001), while, in the apical third, both techniques were not significantly different (P > 0.05). When the apical orifice was patent there was a significant propensity for the extrusion of filling materials beyond the apex (P < 0.001) with the Thermafil technique.

Summary The short‐ and long‐term apical seal of root canals obturated with softened alpha‐phase gutta‐percha on plastic core‐carriers, Thermafil, was compared to that of laterally condensed, cold gutta‐percha. Fifty‐one roots from mandibular molars with separate canals, patent canal orifices and curvatures greater than 15 degrees were cleaned and shaped with K‐files and 2.5% sodium hypochlorite to a size 30 at the apex, and flared with Hedstrom files to create a continuously tapering funnel preparation. Canals were randomly obturated with Sealapex root canal sealer and either alpha‐phase gutta‐percha on a plastic Thermafil carrier, or standard beta‐phase gutta‐percha with lateral condensation. Teeth were separated into three groups of 17 each and placed in black India ink for 24 h, 7 days or after 5 months storage in water. The teeth were demineralized, rendered transparent, and apical microleakage determined by the linear measurement of dye penetration. Significant differences in microleakage were noted between the 24 h and 5‐month Thermafil groups (P<0.05), 24‐h and 7‐day lateral condensation groups (P<0.05), and 24‐h and 5‐month lateral condensation groups (p<0.05). There were no significant difierencs between the two techniques at each time interval. It was concluded that both techniques demonstrated a significant increase in apical microleakage over a 5‐month period.

The purpose of this study was to assess the effect of a calcium silicate‐based sealers (CeraSeal) and an epoxy resin‐based sealer (AH Plus) on cytotoxicity and cell migration of stem cell from the human apical papilla (hSCAPs) by using the Alamar Blue, Annexin V‐FICT and wound healing assays. In Alamar Blue assay, hSCAPs exposed to undiluted CeraSeal extract had significantly higher cell viability compared with that observed when cells were treated with AH Plus in all experimental period (p < 0.001). The flow cytometry analysis confirmed the comparison on viable cells and indicated that AH Plus increased apoptosis compared to CeraSeal and the control groups (p < 0.001). Additionally, AH Plus exhibited significantly lower level of cell migration than CeraSeal and the control for up to 48 h observation (p < 0.01). In summary, calcium silicate‐based sealer (CeraSeal) is less cytotoxic and more biocompatible than epoxy resin‐based sealer (AH Plus).