Rosana de Souza Pereira

Avaliação da padronização dos instrumentos endodônticos

Com o objetivo de avaliar a conformidade dimensional dos instrumentos endodonticos manuais em relacao as especificacoes numero 28 da ANSI/ ADA e ISO 3630-1, foi realizada uma investigacao microscopica na ponta de limas manuais de aco inoxidavel tipo K de quatro diferentes marcas comerciais (Kerr, Maillefer, Moyco e CCCord). Foram medidos num microscopio otico de medicao: o diâmetro Do o ângulo e o comprimento da ponta. Os resultados das medidas de dimensoes das pontas revelaram um numero significativo de limas fora das especificacoes, principalmente para o comprimento da ponta. Os valores de Do, apesar de se encontrarem em sua maioria, para todas as marcas pesquisadas, dentro dos limites de tolerância, raramente exibiram o valor nominal exato. (AU)

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

Evaluation of the lengths and angles of the tips of rotatory files in root canal preparations

Purpose: To detect changes in the angles and lengths of the tips of rotary nickel-titanium files after use. Methods: Forty human teeth were prepared with eight sets of rotary ProTaper® Universal nickel-titanium files with a length of 25 mm and rotation of 350 rpm. The files were evaluated in a scanning electron microscope (SEM) at three different times: Group A - before use; Group B - after using each file in the preparation of three molars; and Group C - after using each file in the preparation of five molars. The length of the tip was determined by measuring the length of a straight line drawn parallel to the file axis, from the apex of the tip to its posterior border. The SEM software provided the angle measurements. Data were analyzed by using paired t-tests and Wilcoxon tests. Results: There were no differences between the groups for the S1 file. There was a decrease in length when the F2 file was used to prepare three and five molars, whereas decreases in length were seen when F5 files were used to prepare three or five molars. Conclusion: The results suggest that the tips of the rotary instruments showed significant changes in length and angle even with relatively low use.