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Time‐dependent visco‐elastic creep and recovery of flowable composites
Author(s) -
Baroudi Kusai,
Silikas Nick,
Watts David C.
Publication year - 2007
Publication title -
european journal of oral sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.802
H-Index - 93
eISSN - 1600-0722
pISSN - 0909-8836
DOI - 10.1111/j.1600-0722.2007.00487.x
Subject(s) - creep , materials science , composite material , curing (chemistry) , viscoelasticity , preload , stress (linguistics) , medicine , hemodynamics , linguistics , philosophy
Creep behaviour of flowable composites was evaluated in relation to their filler fraction and the postcure period. Solid cylindrical specimens were prepared (4 × 6 mm) using steel moulds, with thorough light curing from multiple directions at 600 mW cm −2 . The specimens were divided into two groups ( n = 3/material) as follows: group I, loaded 5 min after preparation; and group II, loaded after storage for 1 month in water at 37 ± 1°C. A constant compressive stress of 36 MPa was applied to each specimen for 2 h followed by removal of the weight for 2 h of strain recovery. Axial strain measurements were obtained continuously over the total analysis time of 4 h. The maximum creep strain ranged from 2.04 to 7.69% and from 1.03 to 6.12% for groups I and II, respectively. Flowables that had the highest percentage of filler produced the lowest creep strain. The creep response decreased with 1 month of preload storage. Clinically, the finding of this study suggests that flowable composites are unsuitable for stress‐bearing areas.