Abstract This study aimed to evaluate the effect of apicoectomy performed with a bur or an ultrasonic tip on the adaptation of the filling material to root canal dentin. Twenty human mandibular incisors were selected and prepared with a ProDesign Logic system up to diameter 40/.05. The root canals were filled with Bio-C Sealer (Angelus, PR, Brazil) using the single cone technique and were stored at 37ºC and 95% relative humidity for 7 days. After this period, the apicoectomy of the 3 millimeters of the root apex was performed using Endo-Z bur (Dentsply Sirona) or Bladesonic ultrasonic tip (Helse Ultrasonic, Santa Rosa de Viterbo, Brazil) (n=10). The specimens were scanned by micro-computed tomography (micro-CT; SkyScan 1176) with a voxel size of 8.74 µm after obturation and after apicoectomy. The percentage of voids at the interface between the filling material and the root canal wall was evaluated in the apical 4 mm of the root after apicoectomy, besides the time cutting to both devices. The data obtained were submitted to paired and unpaired t-tests (α = 0.05). Endo-Z and Bladesonic increased the percentage of voids between the filling material and the dentin after apicectomy (p<0.05), and they were similar (p>0.05). Endo-Z has a shorter time to perform apicoectomy compared to Bladesonic (p<0.05). Apicectomies with Endo-Z or Bladesonic could harm the material/dentin interface, while the Endo-Z bur was faster than the Bladesonic ultrasonic tip.

Resumo O objetivo deste estudo foi avaliar o efeito da apicectomia realizada com broca ou inserto ultrassônico na adaptação do material obturador á dentina do canal radicular. Vinte incisivos inferiores humanos extraídos foram selecionados e preparados com o sistema ProDesign Logic até o diâmetro 40/.05. Os canais radiculares foram obturados com Bio-C Sealer (Angelus, PR, Brasil) por meio da técnica de cone único e foram armazenados em estufa a 37ºC e umidade relativa de 95% por 7 dias. Após esse período, foi realizada apicectomia dos 3 milímetros apicais utilizando broca Endo-Z (Maillefer - Dentsply) ou inserto ultrassônico BladeSonic (Helse Ultrasonic, Santa Rosa de Viterbo, Brasil) (n=10). Os espécimes foram escaneados por meio de microtomografia computadorizada (micro-CT; SkyScan 1176) com tamanho de voxel de 8,74 µm após obturação e após apicectomia. Please, correct this sentece to O percentual de falhas na interface entre o material obturador e a parede dentinaria foi avaliado nos 4 mm apicais da raiz apos apicectomia, alem do tempo de corte para ambos dispositivos. Os dados obtidos foram submetidos aos testes t pareado e não pareado (α = 0,05). Endo-Z e Bladesonic aumentaram o percentual de vazios entre o material obturador e a parede da dentina após apicectomia (p<0.05), sendo semelhantes entre si (p>0.05). Endo-Z demonstrou menor tempo para realizar apicectomia em comparação com Bladesonic (p<0.05). Apicectomias com Endo-Z ou Bladesonic podem prejudicar a interface material obturador/dentina, sendo a broca Endo-Z mais rápida que a ponta ultrassônica Bladesonic.

Abstract Introduction Calcium silicate-based sealers demonstrate greater solubility in distilled water. The use of alternative methodologies can help at better understanding the solubility of these materials. Objective To evaluate the effect of the immersion solution and the type of experimental model on the solubility of ready-to-use Bio-C Sealer. Material and method Circular models of polyethylene or bovine dentin (n = 16) were made. After insertion of the sealer, the specimens were kept in an oven at 37°C and 95% humidity for 48h. Subsequently, the samples were weighed on a precision balance to determine the initial mass. Next, the specimens were immersed in 7.5 mL of distilled water (pH 6.5) or PBS (pH 7.0) (n = 8) for 28 days. After that, the samples were removed from the solutions and weighed every 24 hours until the final mass stabilized (0.001g). Test specimens made with Bio-C Sealer were used as a control. Solubility was evaluated according to the difference between the initial and final mass in percentage. Two-Way ANOVA test and Tukey post-hoc tests were performed (α=0.05). Result Immersion in distilled water provided greater solubility compared to PBS regardless of the experimental model (p<0.05). The test specimens showed greater solubility, followed by polyethylene and dentin models immersed in distilled water (p<0.05). There was no difference between the experimental models immersed in PBS (p>0.05). Conclusion Bio-C Sealer presents significantly greater solubility in distilled water than in PBS under all conditions. Experimental model using bovine dentin and PBS as an immersion solution demonstrates reduction in the mass loss of Bio-C Sealer and can be a valuable alternative for evaluating the solubility of bioceramic sealers.

Resumo Introdução Cimentos endodônticos à base de silicato de cálcio demonstram maior solubilidade em água destilada. Emprego de metodologias alternativas pode auxiliar em melhor compreensão sobre a solubilidade desses materiais. Objetivo Avaliar o efeito da solução de imersão e do tipo de modelo experimental na solubilidade de cimento pronto para uso Bio-C Sealer. Material e método Modelos circulares de polietileno ou dentina bovina (n = 16) foram confeccionados. Após inserção do cimento, os espécimes foram mantidos em estufa a 37 °C por 48 horas. Posteriormente, as amostras foram pesadas em balança de precisão para determinação da massa inicial. Na sequência, os espécimes foram imersos em 7,5 mL de água destilada (pH 6,5) ou PBS (pH 7,0) (n = 8) por 28 dias. Após isso, as amostras foram removidas das soluções e pesadas a cada 24 horas até a estabilização da massa final (0,001g). Corpos de prova confeccionados com Bio-C Sealer foram empregados como controle. A solubilidade foi avaliada de acordo com a diferença entre a massa inicial e final em porcentagem. Teste ANOVA Two-Way e teste post-hoc de Tukey foram realizados (α = 0,05). Resultado Imersão em água destilada proporcionou maior solubilidade em comparação com PBS, independentemente do modelo experimental (p < 0,05). Corpos de prova apresentaram maior solubilidade, seguidos dos modelos de polietileno e dentina imersos em água destilada (p < 0,05). Não houve diferença entre os modelos experimentais imersos em PBS (p > 0,05). Conclusão Bio-C Sealer apresenta solubilidade significativamente maior em água destilada do que em PBS em todas condições. Modelo experimental empregando dentina bovina e PBS como solução de imersão demonstra diminuir a perda de massa de Bio-C Sealer e pode ser uma alternativa valiosa para avaliar a solubilidade de cimentos biocerâmicos.

Abstract Introduction Repair materials must have low solubility. Phosphate buffered saline (PBS) allows simulating clinical condition and interaction with dentin may be important for the correct evaluate of mass loss of bioceramic cements. Objective To evaluate the effect of distilled water (DW), or PBS immersion on the solubility of Bio-C Repair (BCR, Angelus) or MTA Repair HP (MTAHP, Angelus) using a dentin tube model. Material and method Bovine dentin tubes with a length of 4 mm, an internal diameter of 1.5 mm and walls thickness of approximately 1 mm were made. The specimens were immersed in DW for 24h, then filled with BCR or MTAHP (n = 14) and stored in an oven at 37°C and 95% humidity for 24h. After being weighed on a precision balance to determine the initial mass, the specimens were immersed in DW (pH 6.5) or PBS (pH 7.0) (n = 7) for 28 days. Empty tubes also were used for calculating the mass loss of the dentin (n=4). After this period, the specimens were weighed until stabilization of the final mass occurred (0.001g). The solubility of each material was evaluated. ANOVA and Tukey statistical tests were performed (α=0.05). Result BCR and MTAHP showing gain of mass in DW and mass loss in PBS (p<0.05). Conclusion The immersion solution influenced the solubility of BCR and MTAHP using dentin tube model. The new methodological proposal could be an alternative to ISO standards for testing the solubility of bioceramic cements.

Resumo Introdução Materiais reparadores devem apresentar baixa solubilidade. Solução salina tamponada com fosfato (PBS) permite simular condição clínica e interação com dentina pode ser importante para correta avaliação da perda de massa de cimentos biocerâmicos. Objetivo Avaliou o efeito da imersão em água destilada (AD) ou PBS na solubilidade de Bio-C Repair (BCR, Angelus) ou MTA Repair HP (MTAHP, Angelus) usando modelo de tubo de dentina. Material e método Tubos de dentina bovina foram confeccionados com 4 mm de comprimento, 1,5 mm de diâmetro interno e 1 mm aproximadamente de espessura de parede. Os espécimes foram imersos em AD por 24h, posteriormente preenchidos com BCR ou MTAHP (n = 14) e armazenados em estufa a 37°C e umidade 95% por 24h. Após serem pesados em balança de precisão para determinação da massa inicial, os corpos de prova foram imersos em AD (pH 6,5) ou PBS (pH 7,0) (n = 7) por 28 dias. Tubos vazios também foram utilizados para o cálculo de perda de massa da dentina (n=4). Após esse período, os espécimes foram pesados até a estabilização da massa final (0,001g). A solubilidade de cada material foi avaliada. Testes estatísticos ANOVA e Tukey foram realizados (α=0,05). Resultado BCR e MTAHP apresentaram ganho de massa em AD e perda de massa em PBS (p<0,05). Conclusão A solução de imersão influencia a solubilidade de BCR e MTAHP usando modelo de tubo de dentina. Nova proposta metodológica poderá ser uma alternativa às normas ISO para testar a solubilidade de cimentos biocerâmicos.

Abstract: The aim of this study was to assess the influence of micro-computed tomography (micro-CT) voxel size on the evaluation of debris accumulation after passive ultrasonic irrigation (PUI) in curved root canals prepared with rotary nickel-titanium files. Mesial root canals (n = 24) of mandibular molars with curvature between 25° and 35° were prepared using ProDesign Logic 30/.05 (PDL) or HyFlex EDM 25/.08 (HEDM). PUI was performed after root canal preparation of all root canals. The specimens were scanned using high-resolution (5 μm voxel size) micro-CT imaging before and after experimental procedures. The percentage of debris was analyzed in the middle and apical thirds using images with 5, 10 and 20 μm voxel sizes. Data were compared using unpaired and paired Student's t-test, ANOVA and Tukey's statistical tests (α = 0.05). There were no differences among the debris analyses performed at different voxel sizes (5, 10 and 20 μm) (p > 0.05). The percentage of debris was similar between the root canals prepared by PDL and HEDM before and after PUI (p > 0.05). In both groups, the percentage of debris decreased in the middle third after PUI (p < 0.05). Within the limitations of this ex vivo study, it can be concluded that the voxel sizes evaluated did not have a significant impact on the analysis of accumulated debris. However, the results showed a tendency for detection of more debris in the analysis performed using a lower voxel size. PUI decreased the debris accumulation in the middle third of curved root canals.

Abstract The aim of this study was to evaluate the filling ability of a new ready-to-use calcium silicate-based sealer using thermoplastic or single-cone technique in flattened root canals. Twenty-four flattened distal canals of mandibular molars with a buccolingual diameter 4 or more times larger than the mesiodistal diameter were selected. The root canals were prepared and filled (n = 12), according to the following techniques: thermoplastic or single-cone technique using Bio-C Sealer. The teeth were scanned using Skycan 1176 micro-computed tomography (micro-CT) - voxel size 8.74 µm, before and after filling the root canal. The percentage of voids in the filled root canals was evaluated, and the data were statistically analyzed using the unpaired t-test (α = 0.05). The root canals filled using the thermoplastic technique created a smaller percentage of voids in the cervical/middle thirds than those filled using the single-cone technique (p < 0.05). There was no difference in the percentage of voids using either technique in the apical third (p > 0.05). The flattened root canals in the cervical/middle thirds were better filled using the ready-to-use calcium silicate-based sealer associated to the thermoplastic technique, compared with the single-cone technique. In the apical third, the techniques showed similar filling ability.