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Platform‐Switching for Cemented Versus Screwed Fixed Dental Prostheses: Reliability and Failure Modes: An In Vitro Study
Author(s) -
Anchieta Rodolfo Brunieira,
Machado Lucas Silveira,
Hirata Ronaldo,
Bonfante Estevam Augusto,
Coelho Paulo G.
Publication year - 2016
Publication title -
clinical implant dentistry and related research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.338
H-Index - 85
eISSN - 1708-8208
pISSN - 1523-0899
DOI - 10.1111/cid.12363
Subject(s) - abutment , implant , materials science , dentistry , dental prosthesis , dental implant , dental abutments , orthodontics , medicine , surgery , structural engineering , engineering
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, E mfils; Colosso Evolution System, I tú, SP , B razil) 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.