Development of new methodologies using Micro-CT to evaluate physicochemical properties of reparative materials and root canal sealers

Author(s)

Fernanda Ferrari Esteves Torres

• Document type: Doctoral Thesis
• Press: Araraquara. 2020-04-14.
• Institution: Universidade Estadual Paulista (Unesp). Faculdade de Odontologia. Araraquara
• Defense date: 2020-03-06
• Advisor: Mario Tanomaru Filho

Abstract

This study evaluated new proposals and the necessary parameters for physicochemical analysis of materials using micro-CT. The materials used in subprojects 1, 2, 3 and 5 were: AH Plus, Fill Canal and Sealapex; Biodentine, IRM and MTA. The ANOVA/Tukey and T tests (α = .05) were applied. Subproject 1- evaluated by micro-CT the effect of immersion time in distilled water (7 and 30 days) on the volumetric change of endodontic materials inserted in simulated cavities in resin molds. All root canal sealers showed a difference in the percentage of volumetric change from 7 to 30 days of immersion. It is concluded that longer immersion periods can influence the volumetric changes of materials. Subproject 2- evaluated the influence of the size of specimens (thickness of 1.50 mm and internal diameters of 6.30, 7.75 and 9, 00 mm) in the volumetric change of materials after immersion in water. Sealapex and Biodentine showed the greatest volume loss. The sample size did not affect the percentage of volumetric change in the materials. Subproject 3- evaluated flow and volumetric filling of materials using different test models. Biodentine showed less flow and better filling than IRM when evaluated in the model with the highest height, while MTA presented the highest flow in this model. There was no difference in the flow and filling provided by the root canal sealers in the different models and methodologies. It is concluded that grooves with higher height and materials with greater flow provide less filling capacity for root-end filling cements, while for root canal sealers there was no influence of the models. Subproject 4- evaluated the effect of immersion in distilled water and PBS on the solubility and volumetric change of calcium silicate-based endodontic sealers (TotalFill BC Sealer, Sealer Plus BC and Bio-C Sealer), compared to AH Plus. Calcium silicate-based sealers showed greater solubility and volumetric changes when immersed in distilled water, showing higher values than AH Plus. Subproject 5- evaluated MTA, IRM and Biodentine, after root-end filling in maxilary premolars. 5A- Volumetric and morphological stability, porosity and voids at the material/dentin interface were evaluated before and after immersion in PBS. All materials showed volumetric stability. Biodentine showed a dimensional reduction and an increase in the porosity and thickness of voids after immersion. It is concluded that MTA presented dimensional and volumetric stability, despite greater porosity than Biodentine. IRM showed stability after immersion. 5B- Evaluated the impact of the voxel size (5, 10 and 20 µm) in the micro-CT evaluation of the material/dentin interface and cement thickness, in addition to the application of different software packages on analysis of volume and porosity of the materials in these cited voxel sizes. Increased volume and thickness were observed, as well as reduced porosity and voids at the interface when the materials were evaluated at 20 µm. When comparing the software packages, Biodentine showed differences for the evaluation of volume and porosity in all voxel sizes. It is concluded that higher resolution and radiopacity of the materials increased the similarity between the software and the reliability of the results. (AU)

• FAPESP's process: 16/00321-0 - Development of new methodologies using micro-CT for evaluation of physicochemical properties of repair materials and endodontic sealers
• Grantee: Fernanda Ferrari Esteves Torres Carvalho
• Support Opportunities: Scholarships in Brazil - Doctorate