Resumo O objetivo deste estudo foi avaliar o efeito da irrigação do espaço preparado para o pino com NaOCl e CaOCl em diferentes concentrações na resistência adesiva de pinos cimentados com um cimento resinoso autoadesivo. Oitenta pré-molares foram seccionados 14 mm do ápice e endodonticamente tratado. As obturações foram parcialmente removidas. Os espécimes divididos randomicamente em 8 grupos (n=10) de acordo com o irrigante usado para irrigação do espaço preparado para pino: SF - soro fisiológico 0,9% (grupo controle); CHX - clorexidina 2%; NaOCl 1% - hipoclorito de sódio 1%; NaOCl 2,5% - hipoclorito de sódio 2,5%; NaOCl 5% - hipoclorito de sódio 5%; CaOCl 1% - hipoclorito de cálcio 1%; CaOCl 2,5% - hipoclorito de cálcio 2,5%; CaOCl 5% - hipoclorito de cálcio 5%. Para cada grupo, irrigação foi realizada com 2 mL de solução. O espaço preparado para pino foi seco com cone de papel absorvente (#80) e os pinos de fibra foram cimentados com cimento resinoso autoadesivo. Os espécimes foram seccionados perpendicularmente e o teste de push-out foi realizado. Microscopia óptica foi usada para analisar o padrão de falha. Os testes de ANOVA e Bonferroni analisaram os dados de resistência adesiva. NaOCl e CaOCl apresentaram similar resistência adesiva, independentemente da concentração usada para irrigar o espaço preparado para pino (p>0,05). SF apresentou os maiores valores de resistência adesiva (11,47 MPa) (p<0,05). Falhas adesivas na interface cimento/dentina foram predominantes (58,33%). Soro fisiológico deve ser o irrigante de escolha para irrigar o espaço preparado para pino antes da cimentação de pinos de fibra com cimentos resinosos autoadesivos. NaOCl e CaOCl afetam negativamente os valores de resistência adesiva.

Abstract The aim of this study was to evaluate the effect of post-space irrigation with NaOCl and CaOCl at different concentrations on the bond strength of posts cemented with a self-adhesive resin cement. Eighty premolars were sectioned 14 mm from the apex, and endodontically treated. The root canal filling was partially removed. Specimens were randomly assigned into 8 groups (n=10), according to the irrigant for post-space irrigation: SS - 0.9% saline solution (control group); CHX - 2% chlorhexidine; 1% NaOCl - 1% sodium hypochlorite; 2.5% NaOCl - 2.5% sodium hypochlorite; 5% NaOCl - 5% sodium hypochlorite; 1% CaOCl - 1% calcium hypochlorite; 2.5% CaOCl - 2.5% calcium hypochlorite; and 5% CaOCl - 5% calcium hypochlorite. For each group, irrigation was performed continuously with 2 ml of solution. The post-spaces were dried with paper points (#80), and glass fiber posts were cemented using a self-adhesive resin cement. The specimens were sectioned perpendicularly and the push-out test was performed. Optical microscopy was used to analyze the failure mode. ANOVA and Bonferroni tests analyzed the bond strength data. NaOCl and CaOCl presented similar bond strength regardless the concentration used to irrigate the post-space (p>0.05). SS showed the highest bond strength (11.47 MPa) (p<0.05). Adhesive failures at the cement/dentin interface were predominant (58.33%). Saline solution should be irrigant of choice to irrigate the post-space before fiber post cementation with self-adhesive resin cement. NaOCl and CaOCl negatively affect the bond strength values.

Objectives The aim of this study was to evaluate the volume of remaining filling material after passive ultrasonic irrigation (PUI) of sodium hypochlorite (NaOCl) and orange oil in mesial canals of mandibular molars, with and without isthmus. Material and Methods Thirty mesial roots of mandibular molars were divided according to the presence or absence of isthmus. Canals were prepared and filled (Micro-CT #1). Filling was removed using rotary instruments, and specimens were sub-divided into three groups according to the irrigation procedures: Conventional – conventional irrigation with NaOCl, PUI/NaOCl – PUI of NaOCl (three activations, 20 seconds each), and PUI/orange oil – PUI of orange oil (Micro-CT#2). Specimens were enlarged using the X2 and X3 ProTaper Next instruments and submitted to the same irrigation protocols (Micro-CT #3). Results No differences were found between the experimental groups in each stage of assessment (P>0.05). The volume of residual filling material was similar to that in Micro-CT #2 and Micro-CT #3, but lower than that observed in Micro-CT #1 (P<0.05). When groups were pooled according to the presence or absence of an isthmus, volume of residual filling material was higher in specimens presenting isthmus (P<0.05). Conclusions PUI of NaOCl or orange oil did not improve filling removal. Isthmus consists in an anatomical obstacle that impairs the removal of filling material.

OBJECTIVE: This study has two aims: 1) to evaluate the apical transportation of the Wizard CD Plus and ProTaper Universal after preparation of simulated root canals; 2) to compare, with Adobe Photoshop, the ability of a new software (Regeemy) in superposing and subtracting images. MATERIAL AND METHODS: Twenty five simulated root canals in acrylic-resin blocks (with 20º curvature) underwent cone beam computed tomography before and after preparation with the rotary systems (70 kVp, 4 mA, 10 s and with the 8×8 cm FoV selection). Canals were prepared up to F2 (ProTaper) and 24.04 (Wizard CD Plus) instruments and the working length was established to 15 mm. The tomographic images were imported into iCAT Vision software and CorelDraw for standardization. The superposition of pre- and post-instrumentation images from both systems was performed using Regeemy and Adobe Photoshop. The apical transportation was measured in millimetres using Image J. Five acrylic resin blocks were used to validate the superposition achieved by the software. Student's t-test for independent samples was used to evaluate the apical transportation achieved by the rotary systems using each software individually. Student's t-test for paired samples was used to compare the ability of each software in superposing and subtracting images from one rotary system per time. RESULTS: The values obtained with Regeemy and Adobe Photoshop were similar to rotary systems (P>0.05). ProTaper Universal and Wizard CD Plus promoted similar apical transportation regardless of the software used for image's superposition and subtraction (P>0.05). CONCLUSION: Wizard CD Plus and ProTaper Universal promoted little apical transportation. Regeemy consists in a feasible software to superpose and subtract images and appears to be an alternative to Adobe Photoshop.

Este estudo objetivou avaliar a influência do tipo de cimento endodôntico (um cimento à base de resina de salicilato e dois cimentos endodônticos) e do tempo decorrido entre a obturação do conduto e a cimentação do pino de fibra na adesão de pinos de fibra à dentina radicular bovina. Sessenta dentes bovinos foram divididos em seis grupos (n=10), considerando um desenho experimental de dois fatores (3x2): cimento endodôntico em três níveis [à base de resina epóxica (AH Plus), eugenol (Endofill) e resina de salicilato e MTA (MTA Fillapex)] e o tempo para cimentação em dois níveis (cimentação imediata e 15 dias pós a obturação). Após cimentação do pino de fibra, fatias com 2 mm de espessura foram obtidas e submetidas ao teste de push-out. Os padrões de falha foram analisados em estereomicroscópio (40×) e classificados em: adesiva na interface cimento/dentina, adesiva cimento/pino, coesiva do cimento, coesiva do pino, coesiva da dentina e mista. Os dados foram analisados através dos testes de ANOVA a dois fatores e post hoc de Tukey (α=0,05). Quando os pinos de fibra foram cimentados imediatamente após a obturação dos condutos, a resistência adesiva foi similar, independentemente do tipo de cimento endodôntico. Entretanto, após 15 dias, os dentes obturados com cimento resinoso à base de resina epóxica apresentaram os maiores valores de resistência adesiva (p<0,05). Os valores de resistência adesiva do mesmo cimento nos diferentes tempos experimentais não foram alterados. O principal tipo de falha foi adesiva na interface cimento/dentina (89,4%). O tempo decorrido entre a obturação dos condutos e a cimentação do pino não influenciou a adesão do pino de fibra à dentina radicular. Por outro lado, o tipo de cimento endodôntico influencia a adesão entre dentina radicular e pinos de fibra.

This study aimed to assess the influence of the type of endodontic sealer (salicylate resin-based sealer vs. two endodontic sealers) and the time of fiber post cementation after root filling on the post adhesion to bovine root dentin. Sixty bovine roots were assigned to six groups (n=10), considering an experimental design with two factors (factorial 3x2): endodontic sealer factor in three levels [epoxy resin-based sealer (AH Plus), eugenol-based sealer (Endofill), and salicylate resin-based sealer plus mineral trioxide aggregate - MTA (MTA Fillapex)] and time for post cementation factor in two levels (immediate post cementation or 15 days after root canal filling). After post cementation, 2-mm-thick slices were produced and submitted to push-out test. The failure modes were analyzed under a 40× stereomicroscope and scored as: adhesive at cement/dentin interface; adhesive at cement/post interface; cement cohesive; post cohesive; dentin cohesive; or mixed. Data were analyzed using two-way ANOVA and Tukey's post-hoc tests (α=0.05). When the fiber posts were cemented immediately after the root canal filling, the bond strengths were similar, independent of the endodontic sealer type. However, after 15 days, the epoxy resin-based sealer presented higher bond strength than the other sealers (p<0.05). Comparison between each sealer in different experimental times did not reveal any differences. The main failure type was adhesive at dentin/cement interface (89.4%). The time elapsed between the root canal filling and post cementation has no influence on post/root dentin adhesion. On the contrary, the type of endodontic sealer can influence the adhesion between fiber posts and root dentin.