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Effects of diameter, chemical impregnation and hydration on the tensile strength of gingival retraction cords
Author(s) -
Del Rocío NietoMartínez María,
Maupomé Gerardo,
BarcelóSantana Federico
Publication year - 2001
Publication title -
journal of oral rehabilitation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.991
H-Index - 93
eISSN - 1365-2842
pISSN - 0305-182X
DOI - 10.1046/j.1365-2842.2001.00789.x
Subject(s) - ultimate tensile strength , composite material , tearing , materials science , tensile testing
Gingival retraction cords are useful clinical aids but little information is available regarding desirable physical features that would preserve their integrity under tensile forces. The study aimed to establish under experimental conditions the extent to which tensile strength is affected by variation in cord diameter; impregnation with ferric sulphate (FS) or aluminium sulphate (AS); and cord hydration (wet/dry). Commercial cords and standard cotton cords were assayed in an Instron 1137 machine. Data were analysed using t ‐test, and one‐ and four‐way ANOVA . Results indicated that tensile strength for 200 commercial cords was 1˙4950 ± 1˙032 kg; and for 560 cotton cords was 1˙2964 ± 1˙4560 kg. Cord hydration had no significant effect on tensile strength, whereas impregnation with AS or FS, a smaller diameter, and/or being a cotton cord decreased tensile strength ( P < 0˙001). Bivariate analyses showed that hydrated commercial cords had higher tensile strength than dry specimens; hydrated or dry cotton cords were not different. The FS‐impregnated cotton cords had lower tensile strength than AS‐impregnated or control cords, and the effect was greater at higher FS concentrations. This study is one of the first evaluations of the physical properties of cords, highlighting characteristics that may minimize the risk of tearing.