ROEN0310

I 23 clinical report _ obturation I roots3_2010 _Discussion The original single-cone technique performed with conventional sealers has been found to be less effective in sealing root canals than the warm ver- tical compaction technique.11,12 Several root-canal fillingtechniqueshavebeendevelopedtoovercome theshortcomingsofthesingle-conetechnique.One is the warm, vertical gutta-percha technique. The primarycriticismofthistechniqueisthatonlyasin- gle,uncondensedconeispresentintheapicalregion for sealing the root-canal apex. Unlike the lateral condensation technique, the plugger depth for the continuous wave of obturation technique is recom- mended to be within 3 to 5mm of the working length.13,14 Ithasbeenreportedthatthefillingofthe root-canal system using the lateral condensation technique has a better treatment outcome than the single-cone filling technique.15 However, these fill- ings were done with standardised 0.02 taper gutta- percha cones, usually with zinc oxide eugenol based sealers. Because large volumes of this soluble sealer were used, dissolution of the sealer may have had a negative effect on the outcome.16 Schäfer et al. compared the solubility of resin-, silicone-, calcium hydroxide-, zinc oxide–eugenol- and glass-ionomer-based sealers in water and artificial saliva, and reported that the resin-based AHPluslosttheleastamountofweightofallsealers testedinallliquids.17 Pommeletal.comparedsingle- cone, lateral condensation, vertical condensation, Thermafil and System B techniques using a zinc oxide–eugenol-based sealer, and reported that the single-cone technique had the highest leakage.18 On the other hand, Wu et al. studied the leakage of single-cone fillings using a silicone-based sealer for one year and concluded that single-cone fillings prevented fluid transport for one year.16 WithNiTirotarypreparationoftherootcanaland the use of a sealer, single-matched, taper-sized conescouldprovide3-Dfillingoftherootcanalover its entire length without requiring accessory cones or time spent on lateral condensation. Laboratory evidence suggests that a comparable cross-sec- tional area of the canal can be occupied by gutta- percha using single-matched, taper-sized cones as compared with lateral condensation, and that this technique can be performed in significantly less time.19 Hembrough et al. compared the root-canal filling quality and efficiency of lateral condensation using variously tapered gutta-percha cones after preparation of single-rooted, straight root canals with ProFile 0.06 tapered rotary files.20 They found that 0.06 tapered gutta-percha cones were more efficient than 0.02 tapered gutta-percha cones in terms of the number of accessory points used, while the filling quality (measured as the linear amount of sealer present between the gutta-percha mass and the canal wall) was not significantly different for either method. Although this was a lateral conden- sation study, the authors were only able to place an average of one accessory cone in the 0.06 tapered cone group, thereby effectively describing a single- matched,taper-sizedconetechnique.Baletal.com- paredthesealingabilityofrootcanalspreparedwith 0.06 tapered rotary NiTi instruments and filled with either a 0.06 or a 0.02 tapered gutta-percha master cone using lateral condensation and found no dif- ference.21 Zmener etal. prepared the root canals us- ing a rotary system and filled them using the single- cone and lateral condensation techniques.22 They reported that the difference between single-cone and lateral condensation filling was not signifi- cant with the use of a methacrylate-based sealer. De-Deusetal.investigatedthesealingabilityoffour Fig. 2 Fig. 1

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