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Failure behaviour of fatigue‐tested post and cores
Author(s) -
HUYSMANS M.C. D. N. J. M.,
PETERS M. C. R. B.,
VARST P. G. T. VAN DER,
PLASSCHAERT A. J. M.
Publication year - 1993
Publication title -
international endodontic journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.988
H-Index - 119
eISSN - 1365-2591
pISSN - 0143-2885
DOI - 10.1111/j.1365-2591.1993.tb00574.x
Subject(s) - quasistatic process , amalgam (chemistry) , premolar , quasistatic loading , core (optical fiber) , materials science , fracture (geology) , fatigue testing , composite material , orthodontics , dentistry , medicine , chemistry , physics , electrode , quantum mechanics , molar
Summary Evaluation of die long‐term behaviour of restorations in clinical trials can be time‐consuming. A partial alternative to the clinical trial can be found in mechanical fatigue testing. The aim of this study was to evaluate the failure behaviour of post and core restored teeth when subjected to cyclic mechanical loading and to compare it with quasistatic failure. Eighty seven premolar teeth were restored with a titanium alloy post and an amalgam or composite core. Five to 21 days after restoration, the specimens were subjected to cyclic loading (frequency 5 Hz), at an angle of 45° to the long axis of the tooth. The load levels were 50,60,65 and 70% of mean quasistatic failure loads. The specimens were divided into three groups according to their survival time: short (S) (>10 4 cycles), intermediate (I) (10 4 ≥life>10 5 cycles) and long (L) (≥ 10 5 cycles). For both core materials failure behaviour changed after approximately 10 5 cycles, and the change was most marked for the composite group. Catastrophic fatigue failure consisted of core fracture in the amalgam group (three times) and of post fracture in the composite L group (four times). Three post fractures occurred at a site theoretically predisposed to fatigue failure. It was concluded that fatigue failure characteristics of post and core restorations may be very different from those of quasistatic failure. Therefore, in addition to quasistatic tests, fatigue tests are necessary, covering at least 10 5 load cycles.