RESUMEN
OBJECTIVES: The aim of this study was to evaluate the various NiTi rotary instruments regarding their ability to provide a circular apical preparation. MATERIALS AND METHODS: 50 single canal roots were selected, cut at the cementodentinal junction and the coronal 1/3 of the canals was flared using Gates Glidden burs. Samples were randomly divided into 5 experimental groups of 10 each. In group I, GT files, Profile 04 and Quantec #9 and #10 files were used. In Group II Lightspeed was used instead of Quantec. In Group III, Orifice shaper, Profile .06 series and Lightspeed were used. In Group IV, Quantec #9 and #10 files were used instead of Lightspeed. In Group V, the GT file and the Profile .04 series were used to prepare the entire canal length. All tooth samples were cut at 1 mm, 3 mm and 5 mm from the apex and were examined under the microscope. RESULTS: Groups II and III (Lightspeed) showed a more circular preparation in the apical 1mm samples than the groups that used Quantec (Group I & IV) or GT files and Profile .04 series.(Group V)(p < 0.05) There was no significant difference statistically among the apical 3, 5 mm samples. In 5 mm samples, most of the samples showed complete circularity and none of them showed irregular shape. CONCLUSIONS: Lightspeed showed circular preparation at apical 1 mm more frequently than other instruments used in this study. However only 35% of samples showed circularity even in the Lightspeed Group which were enlarged 3 ISO size from the initial apical binding file (IAF) size. So it must be considered that enlarging 3 ISO size isn't enough to make round preparation.
Asunto(s)
Níquel , Titanio , DienteRESUMEN
O objetivo deste estudo foi analisar a capacidade do sistema rotatório Quantec SC de remover guta-percha e/ou cimento de canais quando usado na velocidade de 350 ou 700rpm. Vinte incisivos inferiores extraídos foram obturados pela técnica da condensação lateral com guta-percha e cimento Ketac-Endo. Após seis meses as obturações foram removidas com o sistema rotatório Quantec SC na velocidade de 350 ou 700rpm. Inicialmente foram avaliados o tempo para a remoção da obturação, a extrusão de material obturador bem como o desvio do trajeto do canal, perfuração e a fratura de instrumento. A seguir os dentes foram seccionados longitudinalmente e a limpeza das paredes dos canais foi avaliada usando o software Sigma Scan. Aos dados obtidos foi aplicado o teste estatístico de Kruskal-Wallis. Observou-se que todos os canais exibiram resíduos de material obturador; a 700rpm o tempo de remoção da obturação foi menor, porém,a 350rpm menor quantidade de resíduos de guta-percha e cimento foram observadas. Quanto a extrusão de material obturador, não foram observadas diferenças estatísticas entre as velocidades de 350 e 700rpm. Fraturas de instrumento ocorreram em ambas as velocidades sendo mais frequentes no instrumento nº5; o número de perfurações e desvios do trajeto do canal foi maior na velocidade de 350rpm. Conclui-se que os instrumentos rotatórios do sistema Quantec SC podem ser utilizados para desobstrução de canais na velocidade de 700rpm.
The aim of this study was compare the ability of Quantec SC rotary system to remove gutta-percha and sealer from root canal when used using speed, 350 or 700rpm. Twelve extracted mandibular incisors were filled by lateral condensation with gutta-percha and Ketac-Endo sealer. After six months the root canal obturations were removed with Quantec SC rotary system, at speed of 350 or 700rpm. The teeth were grooved longitudinally and evaluated using the Sigma ScanII software. Were evaluated: time to gutta-percha removal, canal wall cleanliness and extruded material. The Kruskal- Wallis on-way analysis of variance was used to identify any significance differences amongst two groups. The number of canal transportation and fracture instruments was also recorded. All examined teeth had filling residues in the rootcanal; in 700rpm the time of work was reduced but at 350rpm more gutta-percha and cements was removed. Extruded material did not show difference at 350 or 700rpm. Procedures errors, instrument fractures occurred in both speed but most frequently in # 5 instrument; canal transportation and perforation occurred most in 350rpm. According to this studyQuantec SC system could be used at 700 rpm to root canal obsturation remotion.