Platform-Switching for Cemented Versus Screwed Fixed Dental Prostheses: Reliability and Failure Modes: An In Vitro Study

Rodolfo Brunieira Anchieta, Lucas Silveira Machado, Ronaldo Hirata, Estevam Augusto Bonfante, Paulo G. Coelho

Research output: Contribution to journalArticlepeer-review


PURPOSE: The aim of this study was to evaluate the probability of survival of cemented and screwed three-unit implant-supported fixed dental prostheses (ISFDP) using different implant-abutment horizontal matching configurations (regular vs switching platforms).

METHODS: One hundred and sixty-eight implants with internal hexagon connection (4 mm diameter, 10 mm length, Emfils; Colosso Evolution System, Itú, SP, Brazil) were selected for this study according to the horizontal implant-abutment matching configuration (regular or switching) and retention method and divided in four groups (n = 21 per group) as follows: 1) regular platform cemented (IRC); 2) or screw-retained (IRS); 3) switched-platform cemented (ISC); or 4) screw-retained (ISS). Regular and platform-switched abutments (Colosso evolution, 4 mm and 3.3 mm, respectively) were torqued, and 84 three-unit metal bridges were fabricated (first molar pontic). Implants were embedded in polymethyl-methacrylate resin and subjected to step-stress accelerated life testing in water. Weibull distribution was used to determine the probability of survival for a mission of 100,000 cycles at 400 N (90% two-sided confidence intervals). Polarized light and scanning electron microscopes were used for fractographic analysis.

RESULTS: The β values of 0.50, 1.19, 1.25, and 1.95 for groups IRC, IRS, ISC, and ISS respectively, indicated that fatigue accelerated the failure for all groups, except IRC. The cement-retained groups presented significantly higher probability of survival (IRC - 98%, ISC - 59%) than screw-retained groups (IRS - 23% and ISS - 0%). Screw-retained FDPs exclusively failed by abutment-screw fractures, whereas cement-retained presented implant/screw/abutment fractures.

CONCLUSIONS: The probability of survival of cement-retained ISFDP was higher than screw-retained, irrespective of implant-abutment horizontal configuration.

Original languageEnglish (US)
Pages (from-to)830-839
Number of pages10
JournalClinical Implant Dentistry and Related Research
Issue number4
StatePublished - Aug 1 2016


  • Weibull analysis
  • dental implant
  • fatigue
  • fixed dental prostheses
  • fractography
  • reliability

ASJC Scopus subject areas

  • Oral Surgery
  • General Dentistry


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