Apical Leakage of Different Gutta-Percha Techniques sealer and apical voids. Peters4 demonstrated that compacted with an electric compactor in order to some sealer used in lateral condensation might unite with the master cone and fill the rest of the resorb with time. This might decrease the effec- root.10 tiveness of the root canal obturation. Fluid filtration has been used to measure mi- Studies have shown that softened gutta-percha croleakage since 1986. This method has been can easily be moved into the canal irregularities, more acceptable in measuring leakage than linear thus replicating the intricacies of the root canal dye-penetration measurement techniques.11 The system. There are a number of warm gutta-per- samples are not destroyed and it is possible to ob- cha methods. These include warm lateral conden- tain measurements of microleakage at intervals sation, warm vertical condensation, coated carrier over extended time periods. Also, dye penetration systems, injection systems and thermomechani- studies have limitations because trapped air has cal compaction. been shown to restrict the penetration of dye.12,13 The Thermafil technique introduced by Johnson It’s indicated that it is more relevant to measure in 1987 involves placing alpha phase gutta-percha the amount of fluid transversing through a canal on a metal carrier heating and using it to obturate than measuring the length of a gap in a filled ca- the root canal. Currently used carriers are made nal. However, conventional fluid filtration mea- of stainless steel, titanium or plastic. With regard surements are relatively subjective due to direct to sealing of and adaptation to canal walls, Beatty visual readings. A computerized, fully electronic, et al5 reported the Thermafil technique to be supe- reliable and digital air pressure checking system rior to the lateral condensation technique. And, in is required to remove this deficiencies.14 an earlier study we found both thermoplasticized The purpose of this in vitro study was to com- gutta-percha techniques Thermafil and Ultrafil to pare apical microleakage of teeth filled with dif- be superior to lateral condensation.6, 7 ferent gutta-percha techniques using a computer- Another coated carrier system, Soft Core (Soft ized fluid filtration meter. Core System, Copenhagen, Denmark) has re- cently been introduced. The Soft-Core obturators MAtErIALs And MEtHods consist of biocompatible plastic posts, available in Sixty extracted human non-carious single ISO standard sizes and coated with thermoplas- rooted teeth were used in this study. The crowns tic alpha phase gutta-percha.8 The central plastic were removed and a lingual access was prepared core of Soft-Core is round and hollow. Its depth in each tooth and instrumented using step-back corresponds to the diameter and the length of the technique. The teeth were irrigated with 5.25% so- insertion pin. However, Thermafil has a V shaped dium hypochloride before and after recapitulation central plastic core. using a size 60 master apical file and then dried JS Quick-Fill is a recently introduced mechani- with paper points. Sixty teeth were assigned to cally thermoplasticized gutta-percha obturation six groups (10 of each). An additional 6 teeth were method in which a titanium carrier similar to a used for control (3 for negative control and 3 for lentulo is covered with gutta-percha and warmed positive control). After air drying, a #20 K file 2.0 by wall friction resulting from rotating it within mm longer than the working length was passed the root canal. The plasticized gutta-percha is through the apex of each tooth and with the file in impulsed apically, and then the carrier can be re- place three coats of nail polish were applied to ex- moved from the root canal or left in place.9 ternal root surfaces to avoid sealing from the fora- Another warmed gutta-percha technique Sys- men after obturation. The negative control teeth tem B (endodontic heat source unit) designed to were totally coated with three layers of nail polish, modify Schilder’s technique by obturating the root including the apical foramina. Positive controls canal system with a single continuous wave of were left unfilled. thermoplasticized gutta-percha.6 In the first group, the teeth were obturated Lately, Microseal system was introduced. In using the plastic carrier Thermafil (Dentsply, this technique; a master gutta-percha cone is Maillefer, Switzerland) technique. Each canal was first compacted laterally with a spreader and then coated with Kerr sealer (Kerr Pulp Canal Sealer, thermoplasticized gutta-percha is delivered and Kerr, Romulus, MI, USA) and a size 60 Thermafil 98 European Journal of Dentistry