title: Nickel-titanium versus stainless-steel finger spreaders in curved canals.
abstract: Placement of endodontic spreaders to within 1 to 2 mm of the root canal working length has been advocated for optimum gutta-percha obturation. Due to their stiffness, stainless-steel (SS) spreaders will often fail to achieve this position in curved canals. Newly marketed nickel-titanium (NiTi) spreaders may offer an advantage in this regard due to the increased flexibility of these instruments. Seventy mesial and distal mandibular molar canals were instrumented to a #35 master apical file size. Measurements of the canal curvature were made from preoperative radiographs. Canal curvature angles ranged from 0 to 51 degrees. The teeth were placed in a radiographic mount to ensure a constant focal length, and postoperative radiographs were exposed with comparably sized SS and NiTi spreaders inserted into each prepared canal. Measurements of spreader tip to apex distance were made with a micrometer to the nearest 0.02 mm on the radiographs. Using a t test for paired samples, it was shown that NiTi spreaders penetrated to a significantly greater depth than SS spreaders in curved canals (p < 0.001).
authors.affiliation: U.S. Army Dental Activity, Fort Gordon, GA, USA.
authors.forename: K A
authors.initials: KA
authors.lastname: Berry
authors.forename: R J
authors.initials: RJ
authors.lastname: Loushine
authors.forename: P D
authors.initials: PD
authors.lastname: Primack
authors.forename: D A
authors.initials: DA
authors.lastname: Runyan
mesh_terms: D003762:Dental Instruments; D003786:Dental Pulp Cavity / Q000033:anatomy & histology; D005069:Evaluation Studies as Topic; D016014:Linear Models; D009532:Nickel; D012389:Root Canal Obturation / Q000295:instrumentation*; D013193:Stainless Steel; D014025:Titanium; D014092:Tooth Root / Q000033:anatomy & histology
chemical_list: C040654:titanium nickelide; D013193:Stainless Steel; D009532:Nickel; D014025:Titanium