Comparison of the rheological properties of four root canal sealers

Abstract

The flowability of a root canal sealer is clinically important because it improves the penetration of the sealer into the complex root canal system. The purpose of this study was to compare the flowabilities of four root canal sealers, measured using the simple press method (ISO 6876), and their viscosities, measured using a strain-controlled rheometer. A newly developed, calcium phosphate-based root canal sealer (Capseal) and three commercial root canal sealers (AH Plus, Sealapex and Pulp Canal Sealer EWT) were used in this study. The flowabilities of the four root canal sealers were measured using the simple press method (n=5) and their viscosities were measured using a strain-controlled rheometer (n=5). The correlation between these two values was statistically analysed using Spearman's correlation test. The flow diameters and the viscosities of the root canal sealers were strongly negatively correlated (ρ=−0.8618). The viscosity of Pulp Canal Sealer EWT was the lowest and increased in the following order: AH Plus<Sealapex<Capseal (P<0.05). All of the tested root canal sealers showed characteristic time- and temperature-dependent changes in their rheological properties. The viscosities measured using the strain-controlled rheometer were more precise than the flowabilities measured using the simple press method, suggesting that the rheometer can accurately measure the rheological properties of root canal sealers.

Mineral Trioxide Aggregate: A review of clinical usage and investigations of the effects of modifying particle size

“…However, further research is required to determine which points in the elastic modulus curve could best be defined as the working time. 274 In this study, the rheological setting times of the tested glass ionomer cements, defined by the time required to reach 90% of the plateau elastic modulus, are similar to the indentation setting times marketed by the manufacturer for Fuji VII and Fuji IX. In contrast, the rheological setting time for Biodentine was longer than the advertised setting time.…”

“…232 The advantage of using a rheometer to assess endodontic sealers is that this instrument can measure the viscosity of the material as well as its other important properties such as elastic modulus and storage modulus, recording how these change over time. 274 Furthermore, a strong negative correlation exists between flow using the glass plate press method, and viscosity, whereby the greater the flow, the lower the viscosity. 274 This is typical of shear thinning behaviour.…”

“…274 Furthermore, a strong negative correlation exists between flow using the glass plate press method, and viscosity, whereby the greater the flow, the lower the viscosity. 274 This is typical of shear thinning behaviour.…”

“…80 There have also been reports of the flow properties of endodontic sealers. 274 When assessing rheological properties, the parameter of G' is of most interest, since this represents resistance to elastic (temporary) deformation under force. Tracking the G' over time can document the progression of a mixture from a liquid-like state (with less resistance) to a solid-like state (with greater resistance).…”

Eficácia dos cimentos obturadores do sistema de canais radiculares frente a desafio ácido <i>in situ</i>

“…A maior parte das obturações dos canais radiculares é realizada pela associação de cones de guta-percha e cimentos endodônticos (SAGSEN et al, 2011;ASSMANN et al, 2012;ZHOU et al, 2013;OLIVEIRA et al, 2015). As formulações de cimentos utilizadas são à base de: óxido de zinco e eugenol, resina-epóxica, hidróxido de cálcio, MTA/silicato de cálcio, ionômero de vidro, metacrilato, silicone e biocerâmica (CAMILLERI et al, 2013;SHARMA et al, 2014;CHANG et al, 2015). Cimentos à base de óxido de zinco e eugenol, como o Endofill (Dentsply-Herpo, Petrópolis, RJ, Brasil), têm sido amplamente utilizados em Endodontia, apresentam baixo custo, radiopacidade adequada, bom escoamento e longevidade comprovada, porém apresentam substâncias que são nocivas aos tecidos periapicais (PÉCORA et al, 2002;MARIN-BAUZA et al, 2012;ROSA et al, 2013).…”