ROEN0310

24 I I clinical report _ obturation root-canalsealers(PulpCanalSealer,Sealapex;both SybronEndo; EndoREZ, Ultradent; AH Plus) at two different thicknesses. In the thin-layer groups, the sealers demonstrated similar results. In the thick- layer groups, AH Plus had the best performance.23 Overall, greater sealer thickness negatively influ- encedthesealingabilityoftheroot-canalfilling,ex- cept in AH Plus samples. Wu et al. compared sealer distribution in root canals filled by single-cone, lat- eral condensation and vertical condensation using epoxy-resin cement. They reported a significantly higher percentage of sealer-coated canals in the single-cone group and a better sealer distribution.24 The matched-cone technique, however, uses master cones with a greater taper that match the geometryofthefinalNiTiinstrumentationsystems.19 The use of contemporary root-canal sealing systems that claim to create bonds along the sealer–gutta- percha interface via modifications of the sealer or therootfillingmaterialmayalsosupporttheuseofa single-matched, taper-sized cone technique.25–27 It is well known that in order to seal the entire root-canal system, the largest area has to be filled by gutta-percha cones, and the root-canal sealer is onlyemployedasanadditionalmeasuretopromote better adhesion between root-canal walls and the cones. Moreover, sealers are able to fill irregular areas that gutta-percha cones are unable to fill. The single-matched, taper-sized cone technique has many advantages, including: _safecoronalextrusionofexcesscementwithmini- mal extrusion of sealer in the apical direction; _a uniform mass of gutta-percha with less sealer at thecanalwallinterfaceandwithinthefillingmass; _a higher percentage of sealer-coated canals and a better sealer distribution; _significantly less implementation time; _ease of learning; _elimination of lateral stresses during obturation that may result in overfills and root fractures; _higher quality obturation compared with other methods; _nopotentialriskoftissuedamageduetoanincrease in root surface temperature; _nopotentialforobturationmaterialshrinkage;and _lower cost.1,19,20,28–32 An in vitro evaluation of single-matched, taper- sized cone obturation with a fluid filtration method demonstrated results comparable with those of the lateral condensation and Thermafil techniques.33 _Conclusion Use of the single-matched, taper-sized cone technique for cold obturation relies on the original canal shape and the ability to create a tapered cir- cular preparation. A small diameter canal would be suitable for this technique. Oval-shaped and larger diameterrootcanalswouldrequireexcessiveprepa- rationforthistobeeffective.Furtherstudyisneeded toevaluatethesealingabilityofthesingle-matched, taper-sized cone technique in order to determine whethertheseobturationconeswillhaveanaccept- able apical seal._ Editorial note: A list of references is available from the publisher. roots3_2010 Dr Mohammed A.Alshehri Consultant Restorative and Implant Dentistry,Riyadh Military Hospital,Department of Dentistry Assistant Clinical Professor,King Saud University,College of Dentistry,Department of Restorative Dental Sciences P.O.Box 225763 Riyadh 11324 SaudiArabia E-mail:dr_mzs@hotmail.com _contact roots Fig. 3 Fig. 4 Fig. 5