A mathematical and rheological study of the pastes that make up obturator endodontic cement from MTA base
Palavras-chave:
Mathematical Modeling, Rheology, Levenberg-Marquardt Method, MTA, Rheological ModelResumo
The MTA-Fillapex endodontic cement is constituted from base and catalyst pastes. In the present
work we investigated, from several rheological models, the model that described the best relationship between the
shear stress and shear rate for the pastes. To the investigation, five paste lots were selected, and the Brookfield
RST-CPS rheometer was used to the measurements. The rheological laws were deduced according to the models:
Bingham, Ostwald-de Waele, Herschel-Bulkley, and Casson. The models parameters were calculated by means of
our code. We used the Levenberg-Marquardt Method, from the computational platform OCTAVE on the version
5.2.0. Additionally, we analyzed the parameters’ existence domain, the fitted determination coefficient, the maxi-
mum deviation, and the correlation matrix. From this, the preliminary results showed that the Ostwald-de-Waele
was most representative rheological model to characterize the base paste, and to the catalyst paste we had the
Herschel-Bulkley model as the better representation.
