Apical Leakage of Different Gutta-Percha Techniques System B and lateral condensation techniques. They stated that higher sealer content might lead to higher leakage amounts. In the present study, Microseal and lateral condensation techniques showed higher leakage results in 2 years. Also, Cathro and Love25 found that Microseal technique produced a heterogeneous fill, but System B/Ob- tura II technique produced a homogenous fill at all levels of the root canal filling. On the other hand, Silver et al26 compared two vertical condensation techniques Touch’n Heat modified and System B and they found System B produced acceptable obturation. Kytridou et al27 investigated adaptation and short and long term seal ability of Thermafil and System B and found that both obturation techniques produced substan- tial filling material movement in the canal irregu- larities. On the other hand, although no difference were detected between Thermafil and System B, in teeth which were immersed in Indiana ink for 24 hours or 10 days, significantly more leakage was detected in Thermafil group which were im- mersed 67 days in HBS and 90 hours in dye solu- tion. Shakespeare and Donnelly,28 and Guabivala et al29 found less leakage due to lateral condensa- tion than to the JS Quick-Fill technique whereas Pallares and Faus30, Canalda-Sahli et al31 found no statistical difference between them. Davalou et al32 compared sealing ability of System B and Microseal techniques and found statistically no difference. Pomel and Camps19 investigated seal- ing ability of Thermafil, warm vertical condensa- tion technique and single cone technique by using fluid filtration, electrochemical and dye leakage methods. They found no correlation among the re- sults obtained with the three methods of evalua- tion. This result corroborates to other studies that also attempted to compare different microleakage methods.33-37 Therefore, more research should be done about the methodology of leakage tests and standardization is needed for test protocols. So far, fluid filtration method seems the best method for evaluation microleakage for the time being and a computerized fluid meter has some advantages over the conventional method. Even though with these in vitro results, in-vivo apical leakage can- not be determined. Further clinical studies are necessary to confirm these results. ocnLusIons Thermafil, Soft Core,Quick-Fill and System B techniques showed lower leakage than Microseal and lateral condensation. In addition, this new computerized fluid filtration meter allowed quan- titative measurement of leakage easily. rEFErEncEs 1. Nyguen NT. Obturation of the root canal system. In: Co- hens S, Burns, RC, editors. Pathways of the pulp. 3rd ed. St. Louis: CV Mosby Co, 1984. 2. Brayton SM, Davis SR, Goldman M. Gutta-percha root ca- nal fillings. An in vitro analysis. I. Oral Surg Oral Med Oral Pathol 1973;35:226-231. 3. Eguchi DS, Peters DD, Hollinger JO, Lorton L. A compari- son of the area of the canal space occupied by gutta-per- cha following four gutta-percha obturation techniques us- ing Procosol sealer. J Endod 1985;11:166-175. 4. Peters DD. Two-year in vitro solubility evaluation of four Gutta-percha sealer obturation techniques. J Endod 1986;12:139-145. 5. Beatty RG, Baker PS, Haddix J, Hart F. The efficacy of four root canal obturation techniques in preventing apical dye penetration. J Am Dent Assoc 1989;119:633-637. 6. Gencoglu N, Samani S, Gunday M. Dentinal wall adapta- tion of thermoplasticized gutta-percha in the absence or presence of smear layer: a scanning electron microscopic study. J Endod 1993;19:558-562. 7. Gencoglu N, Samani S, Gunday M. Evaluation of sealing properties of Thermafil and Ultrafil techniques in the ab- sence or presence of smear layer. J Endod 1993;19:599- 603. 8. Soft Core®Manual. Soft Core® Dental Production, Copen- hagen K, Denmark. 9. JS Quick-Fill Instructions. JS Dental Manifacturing Inc. Ridgefield, CT, USA. 10. Korzen BH. Endodontic obturation using the MicroSeal technique. Oral Health 1997;87:67-70;73-74. 11. Antonopoulos KG, Attin T, Hellwig E. Evaluation of the api- cal seal of root canal fillings with different methods. J En- dod 1988;24:655-658. 12. Goldman M, Simmonds S, Rush R. The usefulness of dye- penetration studies reexamined. Oral Surg Oral Med Oral Pathol 1989;67:327-332. 13. Spangberg LS, Acierno TG, Yongbum Cha B. Influence of entrapped air on the accuracy of leakage studies using dye penetration methods. J Endod 1989;15:548-551. 14. Orucoglu H, Sengun A, Yilmaz N. Apical leakage of resin 102 European Journal of Dentistry