Figure 1 - available via license: Creative Commons Attribution-NonCommercial 3.0 Unported
Content may be subject to copyright.
Rheological characteristics of the three gutta perchas and Resilon as a function of temperature. (a) Storage (elastic) modulus, G'; (b) Loss (viscous) modulus, G"; (c) Loss tangent, tan δ ; (d) Complex viscosity, η *. OBT, Obtura; DIA, Diadent; MET, Meta; RES, Resilon.
Source publication
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...
Contexts in source publication
Context 1
... viscoelastic changes of the four materials with varying temperature are shown in Figure 1. The shear moduli G' and G" increased with decreasing temperature, and each material showed differences in magnitude (Figures 1a and 1b). ...
Context 2
... viscoelastic changes of the four materials with varying temperature are shown in Figure 1. The shear moduli G' and G" increased with decreasing temperature, and each material showed differences in magnitude (Figures 1a and 1b). At temperatures of 50 -120℃, the G' and G" ranged 10 4 -10 5 Pa order. ...
Context 3
... tan δdecreased slowly with the cooling process, began to abruptly decrease at 35 -45℃, and exhibit- ed a dissimilar behavior among materials based on decreasing temperature (Figure 1c). The increase in elasticity was more magnified than that in viscosity, considering that the value of tan δchanged from 0.8 (Obtura) -2.6 (Resilon) to 0.08 (Resilon) -0.32 (Meta) with decreasing temperature. ...
Context 4
... increase in elasticity was more magnified than that in viscosity, considering that the value of tan δchanged from 0.8 (Obtura) -2.6 (Resilon) to 0.08 (Resilon) -0.32 (Meta) with decreasing temperature. The complex viscosity η * sharply increased in the order of Obtura, Resilon, Diadent, and Meta at the transition temper- ature of 40 -50℃ (Figure 1d). Thermal transition temperature of the filling materials determined by the DSC ...
Context 5
... shown in Figure 1, the magnitudes of G', G", tan δ , and η * at a specific temperature, and the onset temperatures of the rheological phase transition of the filling materials were significantly different among the materials. Meta showed the lowest values of G', G", and η * within a range of 39 -120℃, and had the lowest onset transition temperature (39℃). ...
Context 6
... the materials were cooled down to 40 -50℃, there was a drastic increase in G' and G" by 100 - 1,000 times (Figures 1a and 1b). The loss tangent (G"/G') decreased from 0.8 -2.6 to 0.08 -0.32, which meant that the increase in G' was more mag- nified than that of G" (Figure 1c). ...
Context 7
... the materials were cooled down to 40 -50℃, there was a drastic increase in G' and G" by 100 - 1,000 times (Figures 1a and 1b). The loss tangent (G"/G') decreased from 0.8 -2.6 to 0.08 -0.32, which meant that the increase in G' was more mag- nified than that of G" (Figure 1c). It implied that the visco-plastic and soft materials became more elastic and stiffer over time under a cooling process. ...
Similar publications
Modern microprocessors require many clock cycles to perform the Arithmetic and Logic Unit (ALU) operations. The Arithmetic Logic Unit performs integer addition, subtraction, multiplication and division etc.., Integer division is relatively more complex compared to other operations since it uses more clock cycles and logic circuit. The algorithm is...
In this work, a hardware-architecture for correlation algorithm implementation is presented. The proposed architecture allows real time tracking. For the design the hardware description language VHDL (Very High Speed Integrated Circuit Hardware Description Language) was used, it was implemented on a FPGA (Field Programmable Gate Arrays) Spartan 2....
This paper presents the design and implementation of six Image quality measures used to investigate the similarity between reconstructed images (after Denoising process) and the original ones on Spartan 3E XC3S500E FPGA. Since the visual comparison is too subjective, objective measure of image quality is required. The objective measure takes advant...
This paper presents a fast and compact FPGA based implementation of the Data Encryption Standard (DES) and Triple Data Encryption Standard (TDES) algorithm, widely used in cryptography for securing the Internet traffic. The main objective of this paper is to provide the reader with a deep insight of the theory and design of a digital cryptographic...
Citations
... In other words, both materials exhibited a dominant elastic behavior and a certain rigidity. This finding in consistent with that of Chang et al. 22 Schilder 4 used a plugger to compact the gutta-percha during its cooling to overcome the problem of volumetric shrinkage. The present results suggest that deformed guttapercha previously compacted may partially return to its original shape once the vertical force is removed due to its inherent elastic behavior. ...
Background/purpose
In clinical operations, qualitative differences in the texture and operational feeling of the regular type and soft type back-filled gutta-percha are readily discernible. This study aimed to investigate and compare the thermal behavior and physical properties of the two gutta-percha materials.
Materials and methods
The chemical compositions of regular and soft type Gutta-Percha Obturator® pellets were examined via energy dispersive X-ray spectroscopy. The thermal behaviors of the pellets during heating and cooling were evaluated using a differential scanning calorimeter. Finally, the viscoelastic properties of the two materials during cooling were assessed using a modular compact rheometer.
Results
The soft type gutta-percha contained a greater atomic percentage of zinc than the regular type material. In addition, the soft type gutta-percha exhibited exothermic peaks during cooling, whereas the regular type gutta-percha did not. The two materials exhibited different viscoelastic behaviors under cooling. In particular, the rate of change of the loss factor for the soft type gutta-percha was more than that of the regular type gutta-percha at temperature lower than 80°C.
Conclusion
The soft type gutta-percha underwent significant crystallization during cooling, and therefore exhibited pronounced volume shrinkage. Furthermore, the soft type gutta-percha underwent a greater rate of change in viscoelasticity under cooling than the regular type gutta-percha, and exhibited poorer physical stability. Consequently, in the back-packing procedure, soft type gutta-percha must be compacted more often over time than regular type gutta-percha to ensure the same quality of root canal obturation.
... Many factors are responsible for this failure, so the mechanical factors such as Thermal Behavior of Gutta Percha, Properties of Sealers and Compaction Force during obturation, Method and Techniques of Root filling etc.are considered to be important. The extrusion temperature affects the visco-elastic properties of Gutta-Percha during the injection, cooling, and compaction process in the root canals [2]. The mean specific heat value for gutta-percha was evaluated to be 0.94+ or -0.09 ...
... A variety of materials and techniques have been developed to improve the sealing quality and reinforcing effect of root canal obturation (30). With the CLC technique, it has been shown that the apical seal is best produced when the spreader can be placed close to the working length (31). The spreader's shape and its depth of penetration are considered to be important factors in producing a more homogenous root canal filling (32). ...
Background:
The aim of this study was to evaluate and compare the obturation quality between canals obturated with gutta-percha/AH Plus sealer (GP group) and resin-coated GP/EndoREZ® sealer (ER group).
Methods:
A total sample of 90 mandibular premolar teeth was divided into 2 groups (2 × 45 canals): the GP group and ER group. Each group was further divided into 3 subgroups (n = 15): cold lateral compaction (CLC), warm lateral compaction (WLC) and single cone (SC). The teeth were subsequently embedded in resin and sectioned horizontally at 1, 3, 6 and 9 mm. All sections were then viewed with a stereomicroscope at ×40 magnification. The area occupied by core filling materials was determined using Cell^D software.
Results:
With CLC, the percentage of core filling materials in the ER group was significantly higher than in the GP group at the 1- and 3-mm levels. Similarly, with WLC, the percentage of core filling material in the ER group was significantly higher than in the GP group at the 1-, 3- and 9-mm levels. With SC, the percentage of core filling materials in the ER group was significantly higher than in the GP group at all levels.
Conclusions:
It can be concluded that the resin-coated GP/EndoREZ® sealer is superior to the gutta-percha/AH Plus in the percentage of core filling material.
... In other words, both materials exhibited a dominant elastic behavior and a certain rigidity. This finding in consistent with that of Chang et al. 22 Schilder 4 used a plugger to compact the gutta-percha during its cooling to overcome the problem of volumetric shrinkage. The present results suggest that deformed guttapercha previously compacted may partially return to its original shape once the vertical force is removed due to its inherent elastic behavior. ...
The naturally occurring isoprene rubber component of gutta-percha has been used in dental root canal filling treatments for almost a hundred years owing to its stability and plasticity as a root canal filling material. The traditional warm gutta-percha vertical compaction technique is the major technique for warm gutta-percha root canal obturation. However, the relation between compaction force and temperature change in this technique is still unclear. The purposes of this study were to determine the ideal gutta-percha molding temperature for compaction and to evaluate single and double heating and compaction in the warm vertical compaction procedures using infrared thermography. Gutta-percha was placed in a digital dry bath incubator at temperatures ranging from 25°C to 62°C in order to analyze compaction forces using an Instron universal testing machine. Both single and double heating and compaction procedures were examined using an infrared thermograph model to monitor temperature change when performing the warm gutta-percha vertical compaction procedure. Our results demonstrate that 44–58°C is the ideal temperature to soften gutta-percha for excellent compaction. Heating and compacting gutta-percha twice at 3 mm from the apex can mold the gutta-percha completely.
Background/purpose
In the warm gutta-percha technique, soft-type and regular-type gutta-percha are using for backfilling thermoplasticized injection system. However, there are limited reports about the properties of these backfilling gutta-percha. This study aimed to analyze and compare the composition, thermal behavior and compact force of two types of backfilling gutta-percha.
Materials and methods
Soft-type and regular-type backfilling gutta-percha (B&L BioTech, Fairfax, VA, USA) were investigated. The inorganic and organic fractions of these gutta-perchas were separated by quantitative chemical analysis (n = 6). Their composition was analyzed using energy dispersive spectroscopy. Thermal behavior in response to temperature variations was analyzed using differential scanning calorimetry. Additionally, a compaction model was used to investigate the relation between compaction force and temperature (n = 10).
Results
The soft-type contained more gutta-percha (3.69–5.85%), carbon ratio (38.96–48.52%) and less inorganic substance (86.51–90.45%), zinc ratio (29.36–35.67%). The composition ratio of two types gutta-percha were statistically significant different (P < 0.05). There were three phase transitions of the soft-type gutta-percha which started at 39.84 °C, 49.32 °C and 54.15 °C while the two phase transitions of the regular-type gutta-percha started at 40.48 °C and 53.45 °C. The glass transition temperature of the regular-type gutta-percha (44.24 °C) was higher than that of the soft-type gutta-percha (40.66 °C). Under various setting temperature, the higher compaction force in the regular-type gutta-percha was required (P < 0.05).
Conclusion
The different components in gutta-percha contribute to its differences in thermal behavior. The soft-type had a higher proportion of gutta-percha and lower ZnO which makes the fluidity better than the regular-type.
AimTo compare the penetration resistance (PR) of six thermoplastic gutta-percha (GP) materials against needle penetration at different temperatures.MethodologyThe PR of the following materials based on warm gutta-percha technique: Beefill GP Cartridge (Beefill), GP Obturator-Hard/Medium/Soft (Dia-H, Dia-M, Dia-S), Obtura (Obtura), and Tactendo Gutta (Tactendo), were measured as a function of temperature change (from 30o C to 200o C). The PR was measured using a force gauge, mounted on a motor-driven micrometer stage, which pushed the penetration needle against GP in a glass cylinder at the designated temperatures. Data were analyzed using Kruskal-Wallis ANOVA and Duncan's multiple range tests at 5% significance.ResultsThe mean PR values for all assessed materials ranged from 15.55 MPa to 26.02 MPa at 30°C, decreased to 0.18 - 1.61 MPa at 60°C, and finally reached 0.02 - 0.12 MPa at 200°C. The Obtura had the highest PR values at most of the measured temperatures. At 40 - 60o C, Obtura had the highest PR value (P < 0.05), and Tactendo had the lowest among the tested materials. At 70 - 200o C, both the mean PR values and melt flow temperature (MFR) of Obtura, Dia-H, and Dia-M were significantly higher than those of other materials (P < 0.05).Conclusions
The PR values were changed by both the heating temperature and the brand or type of GP materials tested. Each material was associated with drastic decreases before reaching 60o C in different degrees, and Obtura had the highest PR at most of the measured temperatures.This article is protected by copyright. All rights reserved.
