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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

The effect of temperature on the physical properties of bioceramic sealers

Khoshnoodi, Alireza 22 June 2023 (has links)
INTRODUCTION: The compatibility of EndoSequence BC Sealer (BC Sealer; Brasseler USA, Savannah, GA) for warm vertical compaction has been questioned due to changing physical properties under higher temperature. The aim was to evaluate the effect of heating on the physical properties (flowability and radiopacity) of a new calcium-based root canal sealer (EndoSequence BC Sealer HiFlow [HiFlow]) in comparison with EndoSequence BC Sealer. METHODS: The flow, and radiopacity of the 2 sealers were measured according to ISO 6786/2012 at different temperatures. Forty real printed plastic teeth (incisor) were used to evaluate the flowability of the two Standard EndoSequence BC Sealer and HiFlow EndoSequence BC Sealer into the lateral and apical accessory canals. These evaluation was done with two obturation techniques including single cone and warm vertical condensation. RESULT: The mean flowability was ranging from 22.25 mm to 9.52 mm. The results indicate that there is a statistical difference between the flowability of the two calcium silicate based sealers under all three different temperatures (37˚C, 100˚C and 150˚C). Radiopacity was measured at two different temperatures including 21˚C and 100˚C. The mean gray value ranged from 213.55 to 202.25. Results showed that HiFlow is more radiopaque and there is a statistically significant difference at both temperatures. The results of single cone and warm vertical obturation techniques show that there is no significant difference between the flowability of the two calcium silicate based sealers into the lateral and apical accessory canals at 21°C and there is a significant difference at higher temperatures. CONCLUSIONS: HiFlow BC sealer had higher flow and was more radiopaque, especially at high temperatures, which are generated by the commonly used warm vertical compaction technique.
2

Density of Gutta Percha by Weight in Straight Root Canals and Curved Root Canals after Single Cone, Cold Lateral, and Warm Vertical Condensation

Sparrow, Gerald Clay 01 January 2008 (has links)
The purpose of this study was to compare the density of gutta percha following three different obturation techniques using two split-tooth models. One split-tooth model was constructed with a straight rooted maxillary incisor and the other with the curved palatal root of a maxillary molar. Each tooth was obturated using single cone, cold lateral, and warm vertical obturation techniques without sealer. Each obturation technique was performed 20 times for each of the root systems. The weights of the gutta percha were recorded for each root type and obturation technique by subtracting the post-fill weight from the pre-fill weight of the two split-tooth models. Results show that in the straight canal, the three obturation techniques are significantly different (p < 0.0001). The warm vertical technique had the largest weight of gutta percha, followed by the single cone, and lastly by the cold lateral condensation group. In the curved canal, the three fill types were also significantly different (p < 0.0001). The warm vertical and single cone obturation techniques were not significantly different from one another but were significantly greater in gutta percha weight than the cold lateral technique. In conclusion, within curved canals, warm vertical and single cone techniques were more dense than cold lateral condensation. In the straight canal, the warm vertical was more dense than the single cone which was more dense than the cold lateral technique.

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