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This study investigated the use of Mineral Trioxide Aggregate (MTA) as an apical barrier by comparing the sealing ability and set hardness of white and gray MTA. Forty-four root segments were prepared to simulate an open apex. Apical barriers of white and gray MTA were placed to a thickness of 2 mm or 5 mm. The samples were obturated immediately (one-step) or after the MTA set for 24 h (two-steps). After placement in methylene blue dye for 48 h, the samples were sectioned for leakage analysis and microhardness testing of the barrier. Gray MTA demonstrated significantly less leakage than white MTA (p < 0.001), and the two-step technique showed significantly less leakage than one-step (p < 0.006). The 5-mm thick barrier was significantly harder than the 2 mm barrier, regardless of the type of MTA or number of steps (p < 0.01). Results suggested that a 5 mm apical barrier of gray MTA, using two-steps, provided the best apical barrier.

The purpose of this study was to compare (a) forces generated during lateral compaction and (b) apical microleakage for nickel-titanium (NiTi) and stainless steel (SS) finger spreaders. Twenty-eight extracted human teeth were instrumented using a standardized rotary instrumentation technique. NiTi and SS #30 spreaders were used to obturate molar roots while the forces generated during obturation were measured on a Universal testing machine. Apical microleakage was determined using a fluid filtration method. There was no significant difference in microleakage between spreaders. NiTi spreaders produced significantly less force than SS spreaders in all specimens (p < 0.001).

The purpose of this study was to compare Schick CDR and Trophy RVGui direct digital radiography (DDR) systems for the ability to detect periapical lesions in human cadaver mandibles. Digital radiographs were exposed of teeth with normal periapical areas and of teeth with artificially prepared periapical lesions using both DDR systems. Three examiners independently viewed the images at two different time periods and estimated which bony state was present. The resulting data were subjected to statistical analysis using a two-way ANOVA. Interexaminer variability was statistically analyzed using Spearman's rho. There was no significant difference in the level of accuracy between the two different DDR systems at either observation period. There was a statistically significant high level of agreement between examiners (p < 0.01). In conclusion, there was no significant difference in the accuracy of detecting artificially prepared periapical lesions between Schick CDR and Trophy RVGui DDR systems.

Forty extracted maxillary incisors were decoronated, prepared in a crown-down fashion and randomly divided into two groups of 16 roots each. Remaining roots served as controls. Smear layer was removed with 17% EDTA followed by 5.25% NaOCl, the canals in group N were again rinsed with NaOCl before obturation with laterally compacted gutta-percha and Roth's 801 sealer. The roots in group E were rinsed with 95% ethyl alcohol instead of NaOCl for the final rinse. Leakage was determined using a fluid-flow model. Roots were cleared, split, and sealer penetration into the dentinal tubules was measured under light-microscopy. Group E demonstrated significantly greater sealer penetration (p = 0.002) and significantly less leakage (p = 0.040), than group N. Leakage could not be significantly correlated with sealer penetration (p = 0.725). Under the conditions of this study, we found that a final rinse with 95% ethyl alcohol increased sealer penetration and decreased leakage.

Endodontic diagnosis often requires thermal testing through porcelain fused-to-metal (PFM) and all-ceramic restorations. The purpose of this study was to measure and compare the temperature change during thermal testing by three commonly used methods occurring at the pulp-dentin junction (PDJ) of nonrestored teeth and teeth restored with full coverage restorations made of PFM, all-porcelain, or gold. The methods used to produce a thermal change were (a) an ice stick, (b) 1,1,1,2-tetrafluoroethane (TFE), and (c) carbon dioxide snow. A thermocouple measured temperature changes occurring at the PDJ in 10 extracted premolars when thermal tested by each method over a period of 30 seconds. Temperature reduction was also measured for the same samples restored with full gold crowns, PFM, and Empress crowns. Results showed intact premolars and those restored with PFM or all-ceramic restorations to respond similarly to thermal testing. In these teeth, TFE produced a significantly greater temperature decrease than carbon dioxide snow between 10 and 25 seconds (p < 0.05). In conclusion, application of TFE on a saturated #2 cotton pellet was the most effective method for producing a temperature reduction at the PDJ of intact teeth and those restored with gold, PFM, and all-porcelain when testing for less than 15 seconds.