title: Effect of implant connection and restoration design (screwed vs. cemented) in reliability and failure modes of anterior crowns.
abstract: The mechanical performance of cemented or screw-retained implant-supported crowns with an internal or external configuration is yet to be understood. This in vitro study evaluated the effect of screw-retained and cement-retained prostheses on internal and external implant-abutment connections. Thereby, the reliability and failure modes of crowns were investigated. Eighty-four implants (Emfils; Colosso Evolution system) were divided into four groups (n=21 each): screw-retained and internal connection (Si), screw-retained and external connection (Se), cement-retained and internal connection (Ci), and cement-retained and external connection (Ce). Ti-6Al-4V abutments were torqued (30 Ncm) to the implants, and maxillary central incisor metal crowns were torqued (30 Ncm) or cemented (Rely X Unicem; 3M-ESPE) and subjected to accelerated life-testing in water. Use-level probability Weibull curves and reliability for 50,000 cycles at 150 N were calculated. The β values for Si (1.72), Se (1.50), Ci (1.34), and Ce (1.77) groups indicated that fatigue/damage accumulation accelerated their failure. The Ci group presented the highest reliability, the Se group presented the lowest reliability, and Si and Ce groups presented intermediate reliability. Screw-retained restorations presented mainly abutment fracture. Cement-retained restorations resulted in failures of the screw in the Ce group, but implant/screw fracture in the Ci group.
authors: Department of Biomaterials and Biomimetics, New York University College of Dentistry, New York, NY, USA.
authors: Amilcar C
authors: AC
authors: Freitas
authors: Estevam A
authors: EA
authors: Bonfante
authors: Eduardo P
authors: EP
authors: Rocha
authors: Nelson R F A
authors: NR
authors: Silva
authors: Leonard
authors: L
authors: Marotta
authors: Paulo G
authors: PG
authors: Coelho
mesh_terms: D000497:Alloys; D001696:Biomechanical Phenomena; D002484:Cementation / Q000379:methods*; D002858:Chromium Alloys / Q000737:chemistry; D003442:Crowns; D000044:Dental Abutments; D003722:Dental Alloys / Q000737:chemistry; D019250:Dental Implants, Single-Tooth; D017267:Dental Prosthesis Design; D017268:Dental Prosthesis Retention / Q000379:methods*; D019094:Dental Prosthesis, Implant-Supported; D019232:Dental Restoration Failure; D003799:Dental Stress Analysis / Q000295:instrumentation; D006801:Humans; D007180:Incisor; D008437:Maxilla; D015203:Reproducibility of Results; D019279:Resin Cements / Q000737:chemistry; D013314:Stress, Mechanical; D013499:Surface Properties; D014025:Titanium / Q000737:chemistry; D019415:Torque; D014867:Water / Q000737:chemistry
chemical_list: D000497:Alloys; D002858:Chromium Alloys; D003722:Dental Alloys; C483701:Rely X Unicem; D019279:Resin Cements; D014867:Water; C031462:titanium alloy (TiAl6V4); D014025:Titanium