ABSTRACT
Abstract This study evaluated the Reciproc R25 and Pro-R 25 instruments in unused condition, after one and a second use in endodontic retreatment employing a noncontact 3D light interferometer profiler, scanning electron microscopy (SEM) and cyclic fatigue tests. Twenty single-root teeth were instrumented with Reciproc R25 and filled with gutta-percha and sealer. A 3D profiler with a 20x objective using the Mx™ software was used to evaluate the cutting blade surfaces of Reciproc R25 and Pro-R 25 (n=5 per group) in unused condition, after the first and second uses in retreatment procedures. After retreatment, SEM was used to evaluate the topographic features of the used instruments. Cyclic fatigue tests were performed to compare new to used instruments. One-way ANOVA followed by Tukey test was used to compare the tested instruments before and after the first and second uses. Student t-test was used to compare the different instruments and for cyclic fatigue evaluation. No significant differences were observed in the cutting blade surfaces of Reciproc and Pro-R before and after one and two uses (p>0.05). Reciproc without use showed higher Sa and Sq when compared to Pro-R without use (p<0.05). No differences were observed between Reciproc and Pro-R after one and two uses (p>0.05). New and unused Reciproc showed longer time to fracture than Pro-R instruments (p<0.05), and only Pro-R showed differences between new and used instruments (p<0.05). Retreatment procedures with Reciproc and Pro-R did not change the surface topography of instruments. Reciproc had greater resistance to cyclic fatigue compared with Pro-R.
Resumo Este estudo avaliou os instrumentos Reciproc R25 e Pro-R 25 sem uso, após um primeiro e um segundo uso em retratamento endodôntico com perfilômetro 3D por interferometria de luz sem contato, microscópio eletrônico de varredura (MEV) e testes de fadiga cíclica. Vinte dentes unirradiculares foram instrumentados com Reciproc R25 e obturados com guta-percha e cimento endodôntico. Um perfilômetro 3D com uma objetiva 20x usando o software Mx ™ foi usado para avaliar as superfícies da lâmina de corte do Reciproc e Pro-R (n = 5 por grupo) na condição sem uso, após o primeiro e após um segundo uso em procedimentos de retratamento. Após retratamento, o MEV foi usado para avaliar as características topográficas dos instrumentos utilizados. Testes de fadiga cíclica foram realizados para comparar instrumentos novos com instrumentos usados. O teste One-way ANOVA seguido pelo teste de Tukey foi usado para comparar os instrumentos testados nos diferentes estágios. Para comparar os diferentes instrumentos e para avaliação de fadiga cílcica, foi utilizado o Student t-test. Não foram observadas diferenças estatisticamente significantes nas superfícies das lâminas de corte dos instrumentos Reciproc e Pro-R antes e após um e dois usos (p> 0,05). O Reciproc na condição sem uso apresentou maior Sa e Sq quando comparado ao Pro-R (p <0,05). Não foram observadas diferenças entre Reciproc e Pro-R após um e dois usos (p> 0,05). O Reciproc sem uso apresentou maior tempo de fratura do que os instrumentos Pro-R (p<0,05), e apenas o Pro-R apresentou diferenças entre instrumentos novos e usados (p<0,05). Os procedimentos de retratamento com Reciproc e Pro-R não alteraram a topografia da superfície dos instrumentos. Reciproc apresentou maior resistência à fadiga cíclica em comparação com o Pro-R.
ABSTRACT
This study evaluated the Reciproc R25 and Pro-R 25 instruments in unused condition, after one and a second use in endodontic retreatment employing a noncontact 3D light interferometer profiler, scanning electron microscopy (SEM) and cyclic fatigue tests. Twenty single-root teeth were instrumented with Reciproc R25 and filled with gutta-percha and sealer. A 3D profiler with a 20x objective using the Mx™ software was used to evaluate the cutting blade surfaces of Reciproc R25 and Pro-R 25 (n=5 per group) in unused condition, after the first and second uses in retreatment procedures. After retreatment, SEM was used to evaluate the topographic features of the used instruments. Cyclic fatigue tests were performed to compare new to used instruments. One-way ANOVA followed by Tukey test was used to compare the tested instruments before and after the first and second uses. Student t-test was used to compare the different instruments and for cyclic fatigue evaluation. No significant differences were observed in the cutting blade surfaces of Reciproc and Pro-R before and after one and two uses (p>0.05). Reciproc without use showed higher Sa and Sq when compared to Pro-R without use (p<0.05). No differences were observed between Reciproc and Pro-R after one and two uses (p>0.05). New and unused Reciproc showed longer time to fracture than Pro-R instruments (p<0.05), and only Pro-R showed differences between new and used instruments (p<0.05). Retreatment procedures with Reciproc and Pro-R did not change the surface topography of instruments. Reciproc had greater resistance to cyclic fatigue compared with Pro-R.