RESUMEN
The aim of this in-vitro study was to use dye penetration method to compare the apical microleakage of matched taper single-cone and cold lateral condensation technique in teeth prepared with ProTaper instruments. Eighty [80] human extracted single rooted teeth were used. The teeth were randomly divided into two experimental groups of thirty [30] teeth each and two negative and positive control groups of ten [10] teeth each. The groups were as follows: Group I, Teeth were obturated using single cone obturation technique; Group II, Teeth were obturated using a cold lateral condensation technique. In positive control Group; teeth were instrumented and left unobturated, where as in negative control Group, teeth were instrumented and five [5] teeth were obturated with single cone obturation technique and five [5] teeth with the Lateral condensation technique. The access cavities of all teeth were obturated with Ketac Molar [3M ESPE] to ensure a coronal seal. The specimens were stored for 24 hours in 100% humidity at 37°C to allow the sealer to set. After that the surface of all roots in experimental and positive control groups were then covered with two layers of nail polish, except for the apical area [2mm]. In the negative control group all surfaces of the roots, including the apical area, were covered with two layers of nail polish. Each tooth was subsequently immersed in a freshly prepared 5% aqueous methylene blue dye solution [PH 7.0] at 37°C for seven days, and stored in incubator. Following storage, the roots were cut along their long axis and evaluated under a stereomicroscope to measure the depth of dye penetration. The negative controls showed no dye penetration while, the positive controls showed completely dye penetration. Mean and standard deviation of leakage for experimental groups were, for Single Cone Obturation, 6.42 [SD +/- 3.18], for Lateral Condensation Obturation, 6.44 [SD +/- 1.8]. There was no significant difference between the two groups [p=0.245]. Both the single cone and the lateral condensation obturation techniques proved equally effective in achieving the apical seal