Fig. (1) Periapical x-rays before and after root canal treatments. (a) Preoperative radiograph of upper left first molar (26); (b) One-year follow up radiograph of 26 obturated with vertically condensed gutta-percha and an epoxy-resin sealer; (c) Lower left first molar (36) before root canal treatment; (d) One-year follow up radiograph of 36 obturated with vertically condensed Resilon™ and RealSeal™ sealer. Note the similar radiopacity of the two filling materials (b and d).