Juliana Machado Barroso

Effect of 17% EDTA on removal of canal wall smear layer and calcium hydroxide dressing: part II

^aOBJECTIVE: the aim of this study was to evaluate, by scanning electron microscopy, the effectiveness of 17% EDTA on removal of canal wall smear layer and calcium hydroxide dressing in different thirds of root canal.METHODS: Ttwenty-four premolars were instrumented in the cervical and middle thirds using Gates-Glidden drills. At the working length, the canal was widened up to # 35 file, followed by scaling up to file # 50. After instrumentation, the teeth were divided into four groups according to the treatment received: GI - irrigation performed with 5 ml of NaOCl 2.5 % ; GII - irrigation with 5 ml of 17% EDTA for 2 and a half minutes , submitted to agitation with file # 15, followed by irrigation with 5 ml of 2.5% NaOCl ; GIII - irrigation with 5 ml of NaOCl 2.5% , drying , application of temporary dressing of Ca (OH )2 with propylene glycol and sealing. After 5 days , removing the sealing irrigation with 5 ml of 17% EDTA for 2 and a half minutes , submitted to agitation with file # 15, followed by a final flush with 5 ml of 2.5% NaOCl ; GIV - irrigation with 5 ml of 17% EDTA for 2 and a half minutes , submitted to agitation with file # 15 , followed by irrigation with 5 ml of 2.5% NaOCl , drying and after use of the medication in Ca (OH )2 with the sealing and propylene glycol which was removed after 5 days performing the irrigation with 5 ml of 17% EDTA for 2 and a half minutes , submitted to agitation with file # 15, followed by using 5 ml 2.5% NaOCl . Next, the teeth were prepared and taken to the scanning electron microscope .RESULTS: The images revealed: Group I - a marked presence of smear layer in all three thirds, Group II - removal of almost all of the smear layer in the cervical third and removal of large quantity in the middle third, whereas in the apical third a large quantity of smear layer still remained however, in comparison with the other groups, this was shown to be cleaner; Group III - in the three thirds, the presence of smear layer was observed, which was shown to be much less compacted than that observed in Group 1; Group IV- in all the thirds there was reduction of smear layer and Ca(OH)2-based medication, and presence of several unobstructed dentinal tubules could be observed, demonstrating the second best result observed.CONCLUSION: It could be concluded that the use of 17% EDTA favored removal of the smear layer and intracanal medication residues in all thirds of the root canal.^len^aOBJETIVO: Avaliar atraves de Microscopia Eletronica de Varredura, a eficacia do EDTA a 17% na remocao da smear layer e da medicacao de hidroxido de calcio nos diferentes tercos do canal radicular.METODOS: Vinte e quatro pre-molares foram instrumentados nos tercos cervical e medio utilizando-se brocas Gates-Glidden. No comprimento de trabalho realizou-se o alargamento ate a lima #35 seguido do escalonamento ate a lima #50. Apos, os dentes foram divididos em quatro grupos de acordo com o tratamento recebido: GI - irrigacao realizada com 5 ml de hipoclorito de sodio a 2,5%; GII - irrigacao com 5 ml de EDTA 17%, durante 2 minutos e meio, submetidos a agitacao com a lima #15, seguidos de uma irrigacao com 5 ml de NaOCl a 2,5%; GIII - irrigacao com 5 ml de hipoclorito de sodio a 2,5%, secagem, aplicacao de medicacao intracanal de Ca(OH)2 associado ao propilenoglicol e selamento, apos 5 dias, remocao do selamento, irrigacao com 5 ml de EDTA 17%, durante 2 minutos e meio, submetidos a agitacao com a lima #15, seguida de irrigacao final com 5 ml de NaOCl a 2,5%; GIV - irrigacao com 5 ml de EDTA 17%, durante 2 minutos e meio, submetidos a agitacao com a lima #15, seguidos de uma irrigacao com 5 ml de NaOCl a 2,5%, secagem e apos o uso da medicacao intracanal de Ca(OH)2 associado ao propilenoglicol e selamento que foi removido apos 5 dias realizando-se a irrigacao com 5 ml de EDTA 17%, durante 2 minutos e meio, submetidos a agitacao com a lima #15, seguida da utilizacao de 5 ml de NaOCl a 2,5%. A seguir, os dentes foram preparados e levados ao microscopio eletronico de varredura.RESULTADOS: As imagens revelaram: grupo I - presenca marcante de smear layer nos tres tercos; grupo II - nota-se a menor quantidade de smear layer no terco cervical e medio enquanto no apical ha presenca mais marcante; grupo III- no terco cervical e apical ha presenca de smear layer compactada nas paredes do canal e o aspecto mais disperso da medicacao enquanto no terco medio nota-se presenca da medicacao no interior dos canaliculos; grupo IV- em todos os tercos houve reducao da smear layer e da medicacao e a presenca de varios canaliculos dentinarios desobstruidos.CONCLUSAO: Pode-se concluir que o uso do EDTA a 17% favoreceu a remocao da lama dentinaria e dos residuos da medicacao intracanal em todos os tercos do canal radicular.^lpt