Apically extruded debris in filling removal of curved canals using 3 NiTi systems and hand files

The aim of this study was to assess the amount of apically extruded debris during filling removal with WaveOne Gold (WOG), ProTaper Universal Retreatment (PTR), D-RaCe Retreatment (DRR) or hand files (HF), to compare the working time during filling removal, and to describe failures of NiTi instruments. Forty mesiobuccal roots of maxillary first molars were prepared with WOG Primary, obturated and divided into 4 groups (n=10), according to the instruments used: WOG, PTR, DRR or HF. Distilled water was used as irrigant and the extruded debris were collected in Eppendorf tubes and dried. The amount of extruded debris was determined by subtracting the final from the initial weight. The time of filling removal for each canal was recorded and the instruments used were analyzed pre and post-operatively by SEM. Kruskal-Wallis and Dunn’s test analyzed extruded debris data and ANOVA, followed by Tukey’s test, compared the working time data (α=0.05). Instrument deformation and fracture were described. WOG produced significantly less debris compared with HF and DRR (p0.05). HF, PTR and DRR showed no significant difference (p>0.05). Working time in HF group was significantly higher than others (p<0.05). SEM analyses showed, from the 18 instruments evaluated, 3 fractures and 10 deformations. All instruments tested caused debris extrusion. WOG was associated with less extrusion than DRR and HF. Filling removal with HF was slower than with the other instruments. All NiTi systems presented fracture and deformation

A quantitative analysis of rotary, ultrasonic and manual techniques to treat proximally flattened root canals

OBJECTIVE: The efficiency of rotary, manual and ultrasonic root canal instrumentation techniques was investigated in proximally flattened root canals. MATERIAL AND METHODS: Forty human mandibular left and right central incisors, lateral incisors and premolars were used. The pulp tissue was removed and the root canals were filled with red die. Teeth were instrumented using three techniques: (i) K3 and ProTaper rotary systems; (ii) ultrasonic crown-down technique; and (iii) progressive manual technique. Roots were bisected longitudinally in a buccolingual direction. The instrumented canal walls were digitally captured and the images obtained were analyzed using the Sigma Scan software. Canal walls were evaluated for total canal wall area versus non-instrumented area on which dye remained. RESULTS: No statistically significant difference was found between the instrumentation techniques studied (

Centering and transportation: in vitro evaluation of continuous and reciprocating systems in curved root canals

One of the goals of endodontic therapy is the shaping and cleaning of the root canal system. In recent years, there has been multiple systems instrumentation, and changes in their dynamics are central to maintain the original shape of the canal after preparation. Aims: The aim of this study was to evaluate centering and transportation in curved root canals after using ProTaper® and MTwo® in continuous rotation, Reciproc® in reciprocating motion, and a step-down manual instrumentation technique. Settings and Design: Mesiobuccal roots of human extracted the first and second maxillary molars were selected and the canals (n = 60) were divided into four groups according to the preparation techniques: PT-ProTaper®; MT-MTwo®; RE-Reciproc®; MI-manual instrumentation. Subjects and Methods: The final apical diameter was standardized to a size 25. Centering and transportation were evaluated by cone-beam computed tomography and Adobe Photoshop 8.0 software. Statistical Analysis Used: The data were statistically analyzed by ANOVA and Tukey post hoc. Results: Results of transportation showed no statistical differences (P > 0.05) between groups, and significantly, difference (P < 0.05) between ProTaper® and Reciproc® was found when evaluating centering ability in the apical third. Conclusions: We concluded that there were no differences in transportation between the evaluated systems for the preparation of curved root canals with an apical instrumentation diameter of #25. For centering ability, in the apical third, ProTaper® presented worst behavior when compared to Reciproc®

Desempenho de sistemas endodônticos rotatórios constante e progressivo no preparo do canal radicular

Objective The aim of this study was to compare the performance of two nickel-titanium rotary systems regarding the preparation time, final shape of canal, incidence of aberration, transportation, and fracture of instrument. Methods A total of 40 simulated canals in resin blocks with 30o curves and a length of 17 mm were divided randomly into two groups: preparation with ProTaper and BioRaCe systems up to F5 and BR5 respectively. Pre- and post-operative canal images were taken and superimposed in order to identify aberrations, transportation, and to take measurements of the canal width. In addition, the preparation time and instrument fractures were recorded. The data were analyzed using Student's t test. Results There is no difference (p>.05) comparing the systems regarding preparation time, canal aberration, and instrument fracture rates. The progressive tapered instruments of ProTaper prepared significantly larger canal widths in the apical third (p0,05). Os instrumentos progressivos do ProTaper resultou em canais significativamente mais largos no terço apical (p<0,05). Conclusão Os dois sistemas rotatórios avaliados resultaram em preparo endodôntico seguro, com poucas alterações e fratura de instrumento

Habilidade de centralização, transporte do canal e modificações de superfície do ProTaper F2 e F3 utilizados em rotação contínua e movimento reciprocante em canais curvos

Aims: To evaluate the centering ability, canal transportation and surface modifications of F2 and F3 ProTaper Universal (PT) instruments used in continuous rotation (CR) and reciprocating motion (RM) for the preparation of curved root canals. Material and methods: sixty mesiobuccal root canals of upper molars with curvatures between 25º and 35° were divided into three groups: I - PT in CR up to F3; II - PT in RM up to F3; III - F2 and F3 PT instruments in RM. Cone Beam Computed Tomography images were obtained before and after instrumentation. The scans were superimposed to determine the centering ability and canal transportation in apical, medium and cervical thirds. The apical 6 mm of the F2 and F3 files were evaluated under Scanning Electron Microscope before and after 1, 3 and 6 uses to assess distortion, surface wear and fracture. The statistical analysis of centering ability and canal transportation were performed by Kruskal–Wallis and ANOVA, respectively. The scores for deformation and surface wear were compared using ANOVA. Fisher’s exact test was used for the evaluation of instrument fracture. Results: there were no significant differences between groups regarding centering ability and canal transportation, as well as, for distortion, surface wear and fracture (p>.05). Conclusion: F2 and F3 instruments can be used for curved canals instrumentation. However, when used for entire canal preparation, F2 and F3 should be discarded after single use.Objetivos: avaliar a centralização, transporte do canal e modificações de superfície dos intrumentos ProTaper Universal (PT) F2 e F3 utilizados em movimento de rotação continua (CR) e movimento reciprocante (RM) no preparo de canais curvos. Materiais e métodos: sessenta canais mesiovestibulares de molares superiores com curvaturas entre 25o e 35o foram divididos em três grupos: I – PT em CR até F3; II – PT em RM até F3; III – instrumentos F2 e F3 em RM. Foram obtidas imagens de Tomografia Computadorizada Cone Beam antes e após a instrumentação. As imagens foram sobrepostas para determinar a centralização e transporte do canal nos terços apical, médio e cervical. Os 6 mm apicais dos instrumentos F2 e F3 foram avaliados por Microscopia Eletrônica de Varredura antes e após 1, 3 e 6 usos para verificar distorções, desgaste de superfície e fratura. A análise estatística da centralização e transporte do canal foi feita pelos testes de Kruskall-Wallis e ANOVA, respectivamente. Os escores de deformação e desgaste de superfície foram comparados pelo teste de ANOVA. O teste exato de Fisher foi utilizado para avaliar a fratura dos instrumentos. Resultados: não houve diferença estatística entre os grupos testados quanto aos testes de centralização e transporte do canal, assim como para distorção, desgaste de superfície e fratura dos instrumentos (p>.05). Conclusões: os instrumentos F2 e F3 podem ser utilizados no prepare de canais curvos. Entretanto, quando usados para o preparo completo do canal radicular, F2 e F3 devem ser descartados após uso único

Habilidade de centralização, transporte do canal e modificações de superfície do ProTaper F2 e F3 utilizados em rotação contínua e movimento reciprocante em canais curvos

Aims: To evaluate the centering ability, canal transportation and surface modifications of F2 and F3 ProTaper Universal (PT) instruments used in continuous rotation (CR) and reciprocating motion (RM) for the preparation of curved root canals. Material and methods: sixty mesiobuccal root canals of upper molars with curvatures between 25º and 35° were divided into three groups: I - PT in CR up to F3; II - PT in RM up to F3; III - F2 and F3 PT instruments in RM. Cone Beam Computed Tomography images were obtained before and after instrumentation. The scans were superimposed to determine the centering ability and canal transportation in apical, medium and cervical thirds. The apical 6 mm of the F2 and F3 files were evaluated under Scanning Electron Microscope before and after 1, 3 and 6 uses to assess distortion, surface wear and fracture. The statistical analysis of centering ability and canal transportation were performed by Kruskal–Wallis and ANOVA, respectively. The scores for deformation and surface wear were compared using ANOVA. Fisher’s exact test was used for the evaluation of instrument fracture. Results: there were no significant differences between groups regarding centering ability and canal transportation, as well as, for distortion, surface wear and fracture (p>.05). Conclusion: F2 and F3 instruments can be used for curved canals instrumentation. However, when used for entire canal preparation, F2 and F3 should be discarded after single use.Objetivos: avaliar a centralização, transporte do canal e modificações de superfície dos intrumentos ProTaper Universal (PT) F2 e F3 utilizados em movimento de rotação continua (CR) e movimento reciprocante (RM) no preparo de canais curvos. Materiais e métodos: sessenta canais mesiovestibulares de molares superiores com curvaturas entre 25o e 35o foram divididos em três grupos: I – PT em CR até F3; II – PT em RM até F3; III – instrumentos F2 e F3 em RM. Foram obtidas imagens de Tomografia Computadorizada Cone Beam antes e após a instrumentação. As imagens foram sobrepostas para determinar a centralização e transporte do canal nos terços apical, médio e cervical. Os 6 mm apicais dos instrumentos F2 e F3 foram avaliados por Microscopia Eletrônica de Varredura antes e após 1, 3 e 6 usos para verificar distorções, desgaste de superfície e fratura. A análise estatística da centralização e transporte do canal foi feita pelos testes de Kruskall-Wallis e ANOVA, respectivamente. Os escores de deformação e desgaste de superfície foram comparados pelo teste de ANOVA. O teste exato de Fisher foi utilizado para avaliar a fratura dos instrumentos. Resultados: não houve diferença estatística entre os grupos testados quanto aos testes de centralização e transporte do canal, assim como para distorção, desgaste de superfície e fratura dos instrumentos (p>.05). Conclusões: os instrumentos F2 e F3 podem ser utilizados no prepare de canais curvos. Entretanto, quando usados para o preparo completo do canal radicular, F2 e F3 devem ser descartados após uso único

A new in vitro method to evaluate radio-opacity of endodontic sealers

OBJECTIVES: To evaluate a new method for assessing the radio-opacity of endodontic sealers and to compare radio-opacity values with a well-established standard method. METHODS: The sealers evaluated in this study were AH Plus(®) (Dentsply DeTrey GmbH, Konstanz, Germany), Endo CPM Sealer (EGEO SRL, Buenos Aires, Argentina) and MTA Fillapex(®) (Angelus Dental Products Industry S/A, Londrina, Parana, Brazil). Two methods were used to evaluate radio-opacity: (D) standard discs and (S) a tissue simulator. For (D), ten standard discs were prepared for each sealer and were radiographed using Digora(®) phosphor storage plates (Soredex; Orion Corporation, Helsinki, Finland), alongside an aluminium stepwedge. For (S), polyethylene tubes filled with sealer (n = 10 for each) were radiographed inside the simulator as described. The digital images were analysed using Adobe Photoshop(®) software v. 10.0 (Adobe Systems, San Jose, CA). To compare the radio-opacity among the sealers, the data were analysed by ANOVA and Tukey's test, and to compare methods, they were analysed by the Mann–Whitney U test. To compare the data obtained from dentin and sealers in method (S), Student's paired t-test was used (=0.05). RESULTS: In both methods, the sealers showed significant differences, according to the following decreasing order: AH Plus, MTA Fillapex and Endo CPM. In (D), MTA Fillapex and Endo CPM showed less radio-opacity than aluminium. For all of the materials, the radio-opacity was higher in (S) than in (D). Compared with dentin, all of the materials were more radio-opaque. CONCLUSIONS: The comparison of the two assessment methods for sealer radio-opacity testing validated the use of a tissue simulator block