Methods: canals of 30 straight extracted roots(16 incisors,8 premolars,6 molars) were instrumented using ProTaper (Dentsply-Maillefer,Ballaigues,Switzerland) instruments, NaOCl 5,25% and EDTA 17%. Working-length was set using Morita TrZX (MoritaMfg.Corp.,Japan) to the apical foramen. Roots were randomly divided into 3 groups. Each group of 10 canals was obturated using SystemB (SybronEndo,Orange,CA,USA) and either .06 Meta(MetaBiomedCo.,Korea) or non-standardized Autofit (Analytic-SybronEndo,Glendora,CA,USA) or ProTaper (Dentsply-Maillefer,Ballaigues,Switzerland) gutta-percha cones, and sealer AH+(Dentsply, DeTrey, Zurich, Switzerland). Control radiographs were taken. Roots were embedded in acrylate. 3 transversal sections were performed at 0.5mm, 1mm and 1.5mm, and were examined under direct, polarized light microscope and stereomicroscope(Olympus BX51M, at50 and100X magnification). Images were captured using an Olympus ColorView IIIu digital camera and analyzed with the Analysis Auto system. Data were registered for each section: total area of the canal, area of gutta-percha, total area of the voids, total area of the sealer+debris. Kruskal-Wallis test was used to compare the gutta-percha-filled areas using the 3 types of cones, for each section.
Results: the mean percentage of the gutta-percha-filled area varied at 0.5mm of apex from 76.46±11.35 for Meta cones, to 55.46±35.74 for Analytic cones, and to 54.38±21.72 for ProTaper cones. At 1 mm of apex, the same parameter varied from 75.03±13.42 for Meta cones, to 61.63±16.43 for Analytic cones and 71.44±15.59 for ProTaper cones. At 0.5 mm, a significant difference (p<.05) was found between Meta and the other types of cones. Beyond 1mm, there was no significant difference between the 3 groups.
Conclusions: the vertical condensation technique using .06 Meta cones and SystemB seems to be superior to vertical condensation techniques using other types of gutta-percha cones, in terms of gutta-percha obturated area of the canal, within the first apical mm.