Effectiveness of different final irrigation protocols in removing debris in flattened root canals

ABSTRACT

This study evaluated in vitro the capacity of debris removal from the apical third of flattened root canals, using different final irrigation protocols. Thirty human mandibular central incisors with a mesiodistal flattened root were prepared using rotary instrumentation by Endo-Flare 25.12 and Hero 642 30.06, 35.02, 40.02 files, irrigated with 2 mL of 1 percent NaOCl after each file. The specimens were randomly distributed into 5 groups according to the final irrigation of root canals Group I 10 mL of distilled water (control), Group II 10 mL of 1 percent NaOCl for 8 min, Group III 2 mL of 1 percent NaOCl for 2 min (repeated 4 times), Group IV 10 mL of 2.5 percent NaOCl for 8 min, and Group V 10 mL of 2.5 percent NaOCl for 2 min (repeated 4 times). The apical thirds of the specimens were subjected to histological processing and 6-μm cross-sections were obtained and stained with hematoxylin-eosin. The specimens were examined under optical microscopy at ×40 magnification and the images were subjected to morphometric analysis using the Scion image-analysis software. The total area of root canal and the area with debris were measured in square millimeters. Analysis of variance showed no statistically significant difference (p>0.05) among the groups GI (2.39 ± 3.59), GII (2.91 ± 2.21), GIII (0.73 ± 1.36), GIV (0.95 ± 0.84) and GV (0.51 ± 0.22). In conclusion, the final irrigation protocols evaluated in this study using the Luer syringe presented similar performance in the removal of debris from the apical third of flattened root canals.

RESUMO

Este estudo avaliou, in vitro, a capacidade de remoção de debris do terço apical de canais radiculares achatados, usando diferentes protocolos de irrigação final. Trinta incisivos centrais mandibulares humanos com a raiz mésio-distal achatada foram preparados usando instrumento rotatório Endo-Flare 25.12 e limas Hero 642 30.06, 35.02, 40.02, irrigadas com 2ml de NaOCl 1 por cento após cada lima. Os espécimes foram aleatoriamente distribuídos em cinco grupos de acordo com a irrigação final dos canais radiculares Grupo I 10 mL de água destilada (controle), Grupo II 10 mL de NaOCl a 1 por cento por 8 min, Grupo III 2 mL de NaOCl a 1 por cento por 2 min (repetidos 4 vezes), Grupo IV 10 mL de NaOCl 2,5 por cento por 8 min e Grupo V 10 mL de NaOCl 2,5 por cento por 2 min (repetido 4 vezes). Os terços apicais dos espécimes foram submetidos a processamento histológico de rotina e cortes transversais com 6 μm de espessura foram obtidos e corados com hematoxilina e eosina. Os espécimes foram analisados em microscopia óptica com aumento final de 40 X e as imagens submetidas à análise morfométrica com a utilização do software Scion Image. A análise de variância evidenciou não haver diferença estatística (p>0,05) entre os grupos GI (2,39 ± 3,59), GII (2,91 ± 2,21), GIII (0,73 ± 1,36), GIV (0,95 ± 0,84) e GV (0,51 ± 0,22). Conclui-se que os protocolos de irrigação final utilizando a seringa Luer apresentaram comportamentos semelhantes na remoção de debris do terço apical de canais radiculares achatados.