Analysis of instrumentation protocols, preparation quality and final cleaning of the root canal in mandibular molars

• Ano de defesa: 2021
• Autor(a) principal: Vivacqua, Flavia Darius
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: eng
• Instituição de defesa: Biblioteca Digitais de Teses e Dissertações da USP
• Palavras-chave em Português: Endodontia; Endodontics; Microcomputed tomography; Microscopia Eletrônica de varredura; Microtomografia computadorizada; Preparo do canal radicular; Root canal preparation; Scanning electron microscopy
• Link de acesso: https://www.teses.usp.br/teses/disponiveis/25/25147/tde-08122021-161257/

This work analyzed three instrumentation protocols using micro-tomography, aiming at the quality of endodontic preparation in mesial roots, as well as, verified the effectiveness of final root canal cleaning protocols, with different chemical substances and agitation devices in distal roots. A hundred mandibular molars were selected, 45 of which had 2 distinct mesial canals and all had a distal canal. After scanning escaneamento (SkyScan 1174v2, Bruker-MicroCT, Kontich, Belgium) and volumetric analysis of the mesial roots, they were randomly divided into 3 groups, according to the enlargement of Bassi-Logic file and the working length: G25.06 / + 1 mm; G35.05 / foramen and G50.01 / - 1 mm. The mesial canals were scanned using microtomography SkyScan 1174v2 and analyzed for increase in total and apical volume, centralization and deviation of the preparation, and the percentage of total and apical untouched walls. For intra-group comparison, the Wilcoxon test was used and in the analysis between groups, the Kruskal Wallis and Dunn test (p <0.05). Considering the distal roots, all canals were instrumented with the R50 file and divided into 10 groups according to antimicrobial irrigant and agitation device as follows: 1) CHX + Canal brush, 2) CHX + EasyClean, 3) CHX + Irrisonic, 4) CHX + Canal 1) CHX + Canal brush, 2) CHX + EasyClean, 3) CHX + Irrisonic, 4) CHX + Canal brush + EasyClean, 5) CHX + Canal brush + Irrisonic, 6) NaOCl + Canal brush, 7) NaOCl + EasyClean, 8) NaOCl + Irissonic, 9) NaOCl + Canal brush + EasyClean, and 10) NaOCl + Canal brush + Irrisonic. EDTA 17% was applied as final chelator irrigant in all protocols. Three cycles of 20s agitation were performed, with 2 mL of each irrigant. After completing the final cleaning protocols described, the samples were dried with medium-sized paper points and the roots were longitudinally sectioned for scanning electron microscopy (SEM) analysis of dentin surface. Cleaning of surfaces were assigned to scores (0-3) for quantitative evaluation. Statistical analysis was performed by Kruskal-Wallis and DunnS test (p<0.05). In the mesial root canals analysis, there was a statistical difference in the total volume between the G25.06 / + 1 mm and the other groups (p <0.05). In the apical third, there was a statistical difference between G25.06 / + 1 mm and G50.01 / -1 mm (p <0.05). No statistical differences were found between the groups regarding centralization and deviation of the preparation, and no statistical difference regarding the percentage of untouched walls of the canal, total or apical (p> 0.05). In the distal analysis, the irrigation protocols CHX+Canal brush+EasyClean, CHX+Canal brush+Irrisonic and NaOCl+Canal brush presented statistical difference between cervical and apical third and the middle and apical thirds in CHX+EasyClean. This work observed that the preparation of the mesial canals, with files of a higher tip and less taper, kept the preparation centralized, making a safe apical dentin wear, without causing severe cervical wear. We also found that none of the final cleaning distal protocols performed, did not promoted a thorough cleaning the root canal, the apical third was more critical in relation to cleaning in all groups.