Comparison of the shaping ability of different nickel-titanium instruments in simulated root canals in resin / 口腔疾病防治

Objective @#To compare the shaping ability of 3 different nickel (Ni)-titanium (Ti) systems in simulated root canals in resin and to provide a reference for clinicians.@*Methods@#Forty-eight resin blocks were prepared using the F360 (Komet, Brasseler GmbH & Co., Lemgo, Germany) (Group 1), F6 SkyTaper (20/06) (Komet, Brasseler GmbH & Co., Lemgo, Germany) (Group 2), F6 SkyTaper (25/06) (Komet, Brasseler GmbH & Co., Lemgo, Germany) (Group 3) and Reciproc R25 systems (VDW, Munich, Germany) (Group 4) (n=12 canals/group). The images taken before and after preparation were superimposed and analyzed by Adobe Photoshop v7.0. The amount of resin removed by each system was measured, and the centering ability was assessed. The data were statistically analyzed using SPSS 20.0.@*Results @#At the 1 mm point, the transportation in Group 4 [(0.10 ± 0.03) mm] was significantly greater than that in Groups 2 [(0.05 ± 0.03) mm] and 3 [(0.05 ± 0.03) mm] (P < 0.05). At the 8 mm and 9 mm points, the transportation values in Group 4 [(0.12 ± 0.06) mm and (0.13 ± 0.05) mm] were significantly higher than those in Groups 2 [(0.05 ± 0.05) mm and (0.05 ± 0.05) mm] and 3 [(0.05 ± 0.04) mm and (0.06 ± 0.05) mm] (P < 0.05). At the 10 mm point, the transportation was significantly greater in Group 4 [(0.13 ± 0.06) mm] than in Group 2 [(0.06 ± 0.06) mm].@*Conclusion@#F6 SkyTaper exhibits better centering ability than Reciproc.

AN in vitro study of 4 instruments in the preparation of curved root canals / 实用口腔医学杂志

Objective: To compare ProTaper Universal(PU),ProTaper Next(PN),WaveOne(WO) and M3 in the preparation of simulated curved canals. Methods: 40 simulated root canals were made from translucent resin and randomly divided into 4 groups(n = 10),the canals were prepared by PU,PN,WO and M3 respectively. The efficacy of canal preparation was analyzed. The pre-instrumentation and post-instrumentation images were recorded and the assessment of the canal shape was completed with Photoshop cs6 and Image Pro Plus6. 0. The apical transportation indexes and the amounts of apically extruded debris were measured. Results: WO was the most time-saving in mean working time(P ＜ 0. 05). PN and M3 took less time than PU in shaping the canals at the most levels(P ＜ 0. 05; PN vs M3,P＞ 0. 05). The amounts of apically extruded debris by PN was less than by PU,WO and M3(P ＜ 0. 05). The apical transportation by PN and M3 was less than that by PU and WO(P ＜ 0. 05). Conclusion: WaveOne is the most time-saving in shaping root canals. ProTaper Next and M3 are more effective and time-saving than ProTaper Universal in shaping root canals. ProTaper Next and M3 are comparable for optimally enlarge root canal.

Comparison of the shaping ability of novel thermally treated reciprocating instruments

OBJECTIVES: The present study aimed to evaluate the shaping ability of 2 thermally treated nickel-titanium reciprocating systems in simulated curved canals. MATERIALS AND METHODS: Forty simulated canals were prepared to apical size 25 using Reciproc Blue R25 (VDW) and WaveOne Gold Primary (Dentsply Sirona) instruments. Standard pre- and post-preparation images were taken and superimposed. The removal of resin material was measured at 5 standard points: the canal orifice, halfway between the canal orifice and the beginning of the curve, the beginning of the curve, the apex of the curve, and the end-point of the simulated canal. The data were analysed using the independent sample t-test with a 5% significance threshold. RESULTS: The canals in which Reciproc Blue R25 was used showed a significantly greater widening than those in which WaveOne Gold was used at 4 of the 5 measurement points (p < 0.05). The Reciproc Blue R25 instrument removed significantly more resin from the inner aspect of the curve at 2 of the 5 points and similar amounts at the remaining 3 points. At the 2 apical points, there was no significant difference between the Reciproc Blue R25 and WaveOne Gold Primary instruments. CONCLUSION: Both instruments respected the original canal anatomy; however, WaveOne Gold resulted in a more conservative shape with less transportation.

Método para o ensino de endodontia laboratorial: plataforma radiográfica para canais simulados / Method for teaching endodontic laboratory: the radiographic platform for simulated root canals

O preparo do canal radicular tem sido avaliado por diferentes métodos ao longo dos anos: a microscopia ótica, a microscopia eletrônica de varredura, o exame radiográfico, analises fotográficas, moldagem, os métodos computadorizados e recentemente a análise tomográfica. Até 1987, a grande dificuldade na avaliação estava na ausência de um controle negativo uma vez que o preparo só podia ser avaliado após a instrumentação. Neste ano, Bramante et al. desenvolveram um método que permitiu a análise antes e após o preparo, usando dentes incluídos em resina e em morsa adequada e seccionados transversalmente, o qual se tornou o mais importante método para análise da qualidade do preparo do canal radicular. Em 1991 Sydney et al.3, desenvolveram uma plataforma radiográfica com a finalidade de padronizar as tomadas radiográficas, obtendo numa mesma película as imagens dos instrumentos antes e depois da instrumentação, para em seguida analisar a manutenção do trajeto original do canal radicular ou não. Face às restrições no uso de dentes naturais e as dificuldades de sua obtenção, o ensino básico da endodontica viu-se obrigado a buscar alternativas. Dente estas, o uso de canais simulados tem se mostrado uma opção de grande valia o que gerou ao desenvolvimento de uma plataforma radiográfica específica para estes, tornando-se valioso auxiliar no ensino da Endodontia.

Root canal preparation has been evaluated by different methods along the years: common optical microscope, the scanning electron microscope, radiographic examination, photographic studies, root canal models, computer programs and recently the tomography. Until 1987 the difficulty on analyzing root canal preparation was the negative control. In this year, Bramante et al. introduced a method that allowed the analysis before, during and after instrumentation. In 1991 Sydney et al.3 developed the radiographic platform method that makes possible to get in the same film the position of the file at the beginning and at the end of instrumentation. Deviations and imperfection are directly observed. The importance of simulated root canals in teaching endodontics is significant as we have difficulties and restrictions on getting human tooth for the grad students. The development of a radiographic platform for simulated root canals is an important teaching aid in endodontics.

Canal transportation in simulated root canals instrumented with one progressive taper and two constant taper nickel-titanium rotary systems

This study investigated the occurrence of canal transportation in the apical third of simulated root canals instrumented with progressive and constant taper shaft designed rotary instruments. Thirty simulated resin canals were prepared with progressive taper (ProTaper Universal) and constant taper (Hero 642 and K3) Ni-Ti rotary systems, with 10 canals per group. The pre and post-instrumentation images of the canals were superimposed and the composite images were analyzed with Image Pro Plus 5.0 software. Centering ability of the instruments was assessed by subtracting the amount of resin removed at the inner wall from that removed at the outer wall. Total amount (in mm) of resin removed was recorded by adding the amount of resin removed at the inner and outer walls, comparing the pre and post-preparation images. Data were analyzed statistically by Kruskal Wallis and Median tests (α=5%). There was statistically significant difference (p<0.05) among the groups. ProTaper produced the greatest canal transportation in the apical third. In conclusion, canal transportation occurred in all groups; the constant taper rotary instruments (Hero 642 and K3) presented greater centering ability towards the original canal curve and caused less canal transportation than the progressive taper instruments (ProTaper).

Este estudo investigou a ocorrência do transporte do canal no terço apical de canais simulados preparados com instrumentos rotatórios de conicidade progressiva e constante. Trinta canais simulados em blocos de resina foram preparados com sistemas rotatórios de Ni-Ti de conicidade progressiva (ProTaper Universal) e de conicidade constante (Hero 642 e K3), com 10 canais simulados por grupo. As imagens pré e pós-operatórias dos canais foram superpostas e analisadas com o Programa Image Pro Plus 5.0. A capacidade de manter a centralização do canal foi avaliada pela subtração da quantidade de resina removida da parede interna daquela removida na parede externa. A quantidade total de resina (em mm) removida foi obtida por meio da soma da resina removida das paredes internas e externas do canal, comparando as imagens pré e pós-operatórias. Os dados foram analisados estatisticamente pelo teste de Kruskal Wallis e Teste das medianas (α=5%). Houve diferença estatisticamente significativa (p<0.05) entre os grupos. O Sistema ProTaper produziu o maior transporte do canal no terço apical. Em conclusão, o transporte do canal ocorreu em todos os grupos; os intrumentos rotatórios de conicidade constante (Hero 642 e k3) apresentaram uma grande capacidade de manter o canal centrado e causaram menos transporte do canal do que os instrumentos de conicidade progressiva (ProTaper).