JOURNAL OF PROSTHETIC DENTISTRY THE

Vol. 99 No. 1      JANUARY - 2008

ISSN: 0022-3913      UBIC: 171

RESUMEN

Statement of problem: It has been shown that under cyclic loading, more chipping fractures of the veneer ceramic occur on the occlusal surface of screw-retained implant-supported fixed partial dentures (FPDs) with unrestored screw access holes (SAHs) than in cemented restorations. This lack of stability may result in esthetic and functional problems. Purpose: The purpose of this study was to investígate whether, under dynamic loading, fewer chipping fractures occuron the occlusal surface of screw-retained ceramic veneered implant FPDs with restored SAHs than in those with unrestored SAHs. Material and methods: Twenty screw-retained ceramic veneered 5-unit FPDs were manufactured for a 3-implant situation and divided into 2 groups of 10 unrestored and 10 SAHs restored with adhesive composite resin restorations (Tetric Evo Ceram). A masticatory simulator was used to load the FPDs occlusal to the implant positions for 20,000 cycles with a force of 100 Napplied for 1 second, followed by 1 second of no loading. Three prosthodontists evaluated the FPDs using a light microscope and a dental probe. The number of chipping fractures found were analyzed using a generalized linear model with Poisson response and log link function (a=.05). Results: Investigators found significantly more chipping fractures in the group of screw-retained FPDs with unrestored SAHs. The rate ratio of unrestored versus restored prostheses was 3.29 (P=.006). Conclusions: Adhesive composite resin restorations can significantly reduce the number of chipping fractures occurring around the SAHs of screw-retained implant-supported restorations. (J Prosthet Dent 2008;99:19-24)

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