Influence of bioceramic intracanal medication on the bond strength of bioceramic root canal sealer

Abstract To investigate the influence of the remaining volume of a new intracanal medication based on bioceramic compounds on the bond strength (BS) and formation of an adhesive interface between calcium silicate-based and epoxy resin-based root canal sealers. For this purpose, the specimens were distributed according to the intracanal medication (n = 26): Bio-C Temp (BCT) and Ultracal XS (UXS). The roots were scanned in microCT, and after 7 days, the medication was removed. Then a new scan was performed to evaluate the volume of medication remaining. Subsequently, 40 specimens were redistributed into 2 subgroups (n = 10) and filled according to the sealer used: AH Plus (AHP) and Bio-C Sealer (BCS), to assess the bond strength by using the push-out test, and the adhesive interface by confocal laser fluorescence microscopy (CLSM) and scanning electron microscopy (SEM). The t test showed a smaller remainder of BCT (1.77 ± 0.86) compared with UXS (10.47 ± 5.78), irrespective of the root third evaluated. The BS showed that teeth with BCT + BCS had higher bond strength values (3.70 ± 1.22) when compared to the other groups: BCT + AHP (2.15 ± 1.07), UXS + BCS (3.18 ± 1.09) and UXS + AHP (2.11 ± 1.02) (p<0.001). The cervical third had higher BS when compared with the middle and apical thirds (p < 0.001), and higher number of adhesive failures. The adhesive interface in SEM and CLSM images showed better adaptation for the association between BCT + BCS. Intracanal medication and silicate-based endodontic sealer appeared to interact chemically by forming a biomineralizing layer, allowing for an increase in the bond strength and forming an adhesive interface between the materials, with no or less gap formation

Evaluation of the over and underestimation of two-dimensional morphometric parameters of root canals of lower molars in cone beam computed tomographic images using a microtomography as standard reference

Este estudo propôs avaliar a super e subestimação dos valores de parâmetros morfométricos bidimensionais (área, perímetro, circularidade, diâmetro maior e menor) de canais mesiais de molares inferiores com presença de istmo, em imagens obtidas por meio de tomografia computadorizada de feixe cônico (TCFC), com equipamentos com diferentes especificações técnicas, através do processo de limiarização determinado pelo operador e pelo método automático de Otsu, tendo as imagens de microtomografia computadorizada (microCT) limiarizadas pelo operador como padrão de referência. Molares inferiores (n=10), com presença de istmo na raiz mesial, foram escaneados por microCT e por 3 diferentes tipos de TCFC, (1) Accuitomo (ACC), (2) NewTom 5G (N5G) e (3) NewTom VGi evo (NEVO). Para a padronização e registro das imagens obtidas com os diferentes aparelhos, utilizou-se o programa MevisLab. As imagens das reconstruções axiais obtidas pelos TCFCs foram avaliadas quantitativamente em relação aos parâmetros bidimensionais de área, perímetro, circularidade e diâmetros maior e menor; por 2 examinadores calibrados que delimitavam a área a ser avaliada, e pelo método de Otsu, que determinava de forma automática as estruturas por meio da média dos tons de cinza em relação às densidades das estruturas. O teste de Fleiss Kappa verificou concordância substancial inter e intra-observadores. Os dados quantitativos de área, perímetro, circularidade, diâmetro maior e diâmetro menor apresentaram distribuição normal (teste de Shapiro-Wilk). Dessa forma, foi calculado o erro absoluto em valores médios e desvio padrão. Em seguida foi realizado o teste de análise de variância de 1 fator (ANOVA) para comparação entre os métodos realizado pelo operador e automático de Otsu. Para estabelecer a acurácia entre os aparelhos de TCFC foi calculado a porcentagem de erro absoluto de cada parâmetro tendo como valor de referência as medidas de microCT utilizando a limiarização delimitada pelo operador. O método de limiarização realizado pelo operador apresentou os menores valores de erro absoluto para área, perímetro e diâmetro menor, com diferença (p<0,05) do método de limiarização de Otsu, não evidenciando diferenças entre os aparelhos de TCFC. Os parâmetros de área, circularidade e diâmetro menor apresentaram superestimação, enquanto o perímetro evidenciou subestimação de valores. Pode-se concluir que todos os TCFCs apresentaram super ou subestimação dos parâmetros avaliados. A limiarização determinada pelo operador é mais precisa que a determinada pelo método automático de Otsu para avaliação dos parâmetros morfométricos bidimensionaisThe aim of this study was to evaluates the over and underestimation of the values of two-dimensional parameters of area, perimeter, roudness and major and minor diameter in mesial canals of lower molars with isthmus from images obtained by cone beam computed tomography (CBCT), using equipment with different technical specifications, through operator-delimited treshold and Otsu automatic treshold, using the operator-delimited treshold computerized microtomography images as reference standard. Lower molars (n=10) with the presence of isthmus in their mesial roots were scanned by microCT and three different types of CBCT, (1)3D Accuitomo (ACC), (2) NewTom 5G (N5G) and (3) NewTom VGi evo (NEVO). The MevisLab software was used to standardize and record images obtained with the different devices. The axial reconstructed images obtained through four imaging systems were evaluated quantitatively by two-dimensional parameters of area, perimeter, roudness and major and minor diameter. The structure evaluated was delimited by 2 calibrated examiners using the Otsu method, which automatically determined evaluated area by means of gray tones in relation to the densities of the structures. The Fleiss\' Kappa test was performed to verify inter- and intra-observer agreement. The quantitative data of area, perimeter, roudness and major and minor diameter showed normal distribution (Shapiro-Wilk test) and the absolute error in mean values and standard deviation was calculated. A One-Way analysis of variance (ANOVA) was thereafter performed to compare results obtained through operator-delimited threshold and automatic treshold Otsu method. To establish accuracy between the CBCT devices, the percentage absolute error of each parameter was calculated, having as reference value the microCT measurements obtained using the operator-delimited threshold. The operator-delimited threshold method presented significantly lower absolute error values for area, perimeter and minor diamater (p<0.05) as compared to the Otsu threshold method. There were no significant differences between the TCFC devices. All the devices presented either over or underestimation of the evaluated parameters. The operator-delimited threshold method was more precise than the Otsu automatic method in the evaluation of two-dimensional morphometric parameter

Evaluation of the physicochemical properties of silicone- and epoxy resin-based root canal sealers

Abstract To assess the physicochemical properties of AH Plus, GuttaFlow 2, GuttaFlow BioSeal, and MM Seal, five samples of each root canal sealer were evaluated to determine their setting time (ST), dimensional change (DC), solubility (SL), flow (FL), and radiopacity (RD) according to American National Standards Institute/American Dental Association (ANSI/ADA) Specification 57. The distilled and deionized water obtained from the SL test were subjected to atomic absorption spectrometry to observe the presence of Ca2+, K+, and Na+ ions. Statistical analysis was performed by using one-way ANOVA and Tukey–Kramer tests (p < 0.05). The following results were obtained: ST (min) (AH Plus 463.6 ± 13.22; GuttaFlow 2 24.35 ± 2.78; GuttaFlow Bioseal 17.4 ± 0.55; MM Seal 47.60 ± 4.39), DC (%) (AH Plus 0.06 ± 0.12; GuttaFlow 2 −26.06 ± 1.24; GuttaFlow Bioseal 2.10 ± 1.47; MM Seal 8.47 ± 2.41), SL (%) (AH Plus 0.41 ± 0.21; GuttaFlow 2 5.13 ± 4.11; GuttaFlow Bioseal 3.03 ± 1.05; MM Seal 0.94 ± 0.17), FL (mm) (AH Plus 36.42 ± 0.40; GuttaFlow 2 36.44 ± 0.05; GuttaFlow Bioseal 35.4 ± 0.03; MM Seal 52.75 ± 0.60), and RD (mmAl) (AH Plus 7.52 ± 1.59; GuttaFlow 2 6.85 ± 0.14; GuttaFlow Bioseal 7.02 ± 0.18; MM Seal 3.32 ± 0.90). ST, DC, SL, FL, and RD showed statistical differences among the root canal sealers (p < 0.05). As AH Plus showed the lowest DC and SL values (p < 0.05), the findings indicate that this sample is the only sealer conforming to ANSI/ADA standards