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The effect of temperature on viscosity of root canal sealers
Author(s) -
Lacey S.,
Pitt Ford T. R.,
Yuan X.F.,
Sherriff M.,
Watson T.
Publication year - 2006
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.1365-2591.2006.01154.x
Subject(s) - materials science , grossman , viscosity , composite material , shear thinning , shear rate , rheometer , root canal , rheology , atmospheric temperature range , shear (geology) , thermodynamics , dentistry , medicine , physics , keynesian economics , economics
Aim To test the hypothesis that there was no significant ( α = 0.05) change in viscosity of commercially available root canal sealers with increase in temperature using a high‐performance Advanced Rheometric Expansion System (ARES) rheometer. Methodology Materials tested were Apexit, Tubliseal EWT, Grossman's, AH Plus and Ketac‐endo. Cone‐and‐plate geometry was used (25‐mm diameter, 0.1 radian and gap 0.051 mm). Measurements were carried out for steady‐state viscosity at 25 and 37 °C in the shear rate range of 0.001–50 s −1 at standardized relative humidity and within 30 min from the start of mixing. Five samples were taken for each sealer at each temperature. Results At 25 °C all sealers demonstrated shear thinning. At 37 °C Grossman's (powder : liquid ratio 2 : 1 and 3 : 1) and Ketac‐endo had a rapid rise in viscosity and early set whereas the other sealers were shear thinning. On increasing temperature from 25 °C to 37 °C, Apexit, Tubliseal and AH Plus had reduced viscosity whereas Grossman's 2 : 1, Grossman's 3 : 1 and Ketac‐endo had increased viscosity, which varied with the shear rate. The change in viscosity with change in temperature was significant ( P < 0.05) for all sealers except AH Plus. Conclusions There was a variation in the effect of increasing temperature on each sealer depending on the shear rate. With the exception of AH Plus, a significant ( P < 0.05) change in viscosity was found, and the null hypothesis was rejected.