Rheological characterization of thermoplasticized injectable gutta percha and resilon.
10.5395/JKACD.2011.36.5.377
- Author:
Juhea CHANG
1
;
Seung Ho BAEK
;
In Bog LEE
Author Information
1. Clinic for the Disabled, Seoul National University Dental Hospital, Seoul, Korea.
- Publication Type:Original Article
- Keywords:
Differential scanning calorimeter (DSC);
Gutta percha;
Resilon;
Rheometer;
Thermoplasticized;
Viscoelastic
- MeSH:
Elastic Modulus;
Gutta-Percha;
Handling (Psychology);
Hot Temperature;
Phase Transition;
Root Canal Filling Materials;
Viscosity
- From:Journal of Korean Academy of Conservative Dentistry
2011;36(5):377-384
- CountryRepublic of Korea
- Language:English
-
Abstract:
OBJECTIVES: The purpose of this study was to observe the change in the viscoelastic properties of thermoplasticized injectable root canal filling materials as a function of temperature and to compare the handling characteristics of these materials. MATERIALS AND METHODS: Three commercial gutta perchas and Resilon (Pentron Clinical Technologies) in a pellet form were heated in the Obtura-II system (Obtura Spartan) at 140degrees C and 200degrees C, and the extrusion temperature of the thermoplasticized materials was measured. The viscoelastic properties of the materials as a function of temperature were evaluated using a rheometer. The elastic modulus G', viscous modulus G", loss tangent tandelta, and complex viscosity eta* were determined. The phase transition temperature was determined by both the rheometer and a differential scanning calorimeter (DSC). The consistency of the materials was compared under compacting pressure at 60degrees C and 40degrees C by a squeeze test. RESULTS: The three gutta perchas had dissimilar profiles in viscoelastic properties with varying temperature. The phase transition of softened materials into solidification occurred at 40degrees C to 50degrees C, and the onset temperatures obtained by a rheometer and a DSC were similar to each other. The onset temperature of phase transition and the consistency upon compaction pressure were different among the materials (p < 0.05). Resilon had a rheologically similar pattern to the gutta perchas, and was featured between high and low-flow gutta perchas. CONCLUSIONS: The rheological characteristics of the thermoplasticized root canal filling materials changed under a cooling process. The dissimilar viscoelastic properties among the materials require different handling characteristics during an injecting and compacting procedure.
