Gençoğlu, Oruçoğlu, Helvacıoğlu was heated in a Thermaprep oven for a minimum manufacturer instruction. The sealer was placed of 10 min accordance to the manufacturer’s rec- into the canal and sealer coated master gutta-per- ommendations. The heated obturator was slowly cha was seated. The spreader was inserted along- inserted into the canal within 0.5 mm of the work- side the master cone at the appropriate length for ing length. An inverted cone bur was used to cut compaction. Upon the withdrawal of the spreader through the shank of each carrier. from the canal, a tapered void had formed be- In the second group, JS Quick-Fill obturator (JS tween the compacted gutta-percha cone and the Dental Manufacturing Inc, Ridgefeild, CT) was used root canal walls. The appropriate compactor was in accordance to the manufacturer’s instructions. inserted in the heated gutta-percha cartridge and No #50 Quick-fill obturator (two size smaller than was coated with a uniform layer of material. The the last file used to prepare the apical third of the gutta-percha-coated compactor was then imme- canal) was coated with the sealer and positioned diately carried to the void previously created in the in the canal until a slight resistance was felt. Rota- canal by the spreader and was placed as close to tion was started until gutta-percha plasticity was the working length as possible, avoiding rotation seen and slight pressure was applied apically until as it was inserted. With the application of a resist- reaching working length. An inverted cone bur was ing force to the compactor’s backing-out motion, used to cut through the shank of each carrier.9 but without any apical pressure, rotation of the In the third group, the teeth were obturated compactor started at a speed of 6000 rpm. After with Soft-Core technique. Based on the informa- approximately 2 seconds, the compactor was re- tion obtained from a “size verifier” a #60 Soft-Core moved slowly, whilst being softly pushed against obturator was selected and heated. The root canal one side of the canal. Rotation did not stop until was coated with Kerr sealer and the plasticized the compactor was removed fully from the canal. Soft-Core device was inserted to the apical stop. If the canal was not completely filled, more gut- The handle and insertion pin were removed and ta-percha was placed on the compactor. Excess excess plastic core was cut away with a small in- gutta-percha and sealer removed from the access verted cone bur.8 cavity.10 In the fourth group, canals were obturated us- In the sixth group, the teeth were obturated ing the System B technique (Analytic, Sybron Den- with lateral condensation technique. A gutta- tal Specialties, CA, USA) as recommended by the percha master cone (Hygenic Corp, Akron, Ohio) manufacturer. The canal walls were thinly coated was fitted to within 0.5 mm of the working length. with Kerr sealer and a medium-large non-stan- Freshly mixed Kerr sealer was placed into the ca- dardized gutta-percha cone was placed to within nal. A D11 spreader was inserted 1 mm shorter 0.5 mm. of the working length. A medium-large than the working length. The spreader was kept insert tip, which bound in the canal 3 mm from in the canal until a fine gutta-percha accessory the working length, was used in the obturation of cone was placed. The canal was considered to be the canal. The System B unit was preset to 200C° adequately obturated when enough points were during apical condensation of the primary gutta- placed that the spreader could no longer pen- percha cone (down-pack), to 100C° when adapt- etrate beyond the coronal third of the canal. After ing and condensing the apical portion of the sec- complete canal obturation the coronal gutta-per- ondary (backfill) gutta-percha cone, and finally to cha was removed with a hot instrument. 250C° to soften the remainder of the secondary Following the obturation, the teeth were stored cone prior to vertical condensation. for 2 years at 37°C and 100% humidity. 2 years In the fifth group, canals were obturated using later, each tooth was allowed to bench cool for 1 h the Microseal system (Tycom, Irvine, CA, USA). An prior to testing, in order to reach room tempera- appropriate size of master cone was selected until ture. tug back was confirmed. The appropriate spreader For leakage study, apical roots of 10.00±0.05 was selected that was able to compact the master mm were sectioned using low speed diamond saw. cone of gutta-percha 1.0 mm short of the working Root sections were inserted into the plastic tube length. Finally, the additional appropriate mechan- from the apical side and connected to 18-gauge ical compactors were selected, according to the stainless steel tube. The cyanoacrylate adhesive April 2007 - Vol.1 99 European Journal of Dentistry