title: Comparison of the retentive characteristics of cobalt-chromium and commercially pure titanium clasps using a novel method.
abstract: This study aimed to compare the retentive forces of cast cobalt-chromium (Co-Cr) and commercially pure titanium (cpTi) clasps. A clasp assembly comprising a pair of symmetrical clasps was made to fit the opposite halves of a hardened stainless-steel sphere. This twin clasp was designed to counterbalance the tipping forces when the clasp assembly was drawn from the sphere. A total of 120 clasp assemblies were fabricated in cast Co-Cr and cpTi and placed at undercut depths of 0.25 mm, 0.50 mm, and 0.75 mm (n = 20 for each). For Co-Cr clasps, the retentive forces at these undercuts depths were 2.34 +/- 0.23 N, 4.65 +/- 0.35 N, and 7.56 +/- 0.50 N, respectively. The corresponding retentive forces for cpTi clasps were 1.24 +/- 0.13 N, 2.34 +/- 0.23 N, and 3.70 +/- 0.27 N. The retentive force of cpTi clasps was approximately half that of Co-Cr clasps for the same undercut depth.
authors.affiliation: Faculty of Dentistry, University of Hong Kong, Hong Kong, China.
authors.forename: Edward T P
authors.initials: ET
authors.lastname: Tse
authors.forename: Leo Y Y
authors.initials: LY
authors.lastname: Cheng
authors.forename: Henry W K
authors.initials: HW
authors.lastname: Luk
authors.forename: Frederick C S
authors.initials: FC
authors.lastname: Chu
authors.forename: John
authors.initials: J
authors.lastname: Chai
authors.forename: Tak W
authors.initials: TW
authors.lastname: Chow
mesh_terms: D002858:Chromium Alloys / Q000737:chemistry*; D016734:Dental Clasps; D003764:Dental Materials / Q000737:chemistry*; D003779:Denture Design; D003781:Denture Retention; D006801:Humans; D008422:Materials Testing; D013314:Stress, Mechanical; D013499:Surface Properties; D014025:Titanium / Q000737:chemistry*
chemical_list: D002858:Chromium Alloys; D003764:Dental Materials; D014025:Titanium