Analysis of the physicochemical properties, cytotoxicity and volumetric changes of AH Plus, MTA Fillapex and TotalFill BC Sealer

To evaluate the physicochemical properties and cytotoxicity of AH Plus, MTA Fillapex and TotalFill BC Sealer. Volumetric changes were also evaluating using micro-computed tomography (micro-CT). Radiopacity and flow were evaluated in accordance with the ISO 6876, while setting time was evaluated in accordance with the ASTM- C266-08 specifications. The release of Ca2+ ions and pH were measured with spectrophotometer and pH meter, respectively, after different time intervals (1h, 3h, 24h, 72h, 168h, and 360h). Cytotoxicity was evaluated by MTT reduction assay to check 3T3 cells viability at 24, 48 and 72 hours. Volumetric change was evaluated by micro-CT, by using 30 acrylic teeth, filled with gutta-percha cones and the tested root canal sealer. The samples were evaluated after 168h, 360h and 720h of immersion in distilled water. Data were statistically analyzed by one-way ANOVA and Tukey test or by Kruskal-Wallis and Dunn tests (P<0.05). MTA Fillapex and TotalFill BC Sealer showed lower radiopacity than AH Plus (P<0.05). The MTA Fillapex showed the highest flow, while AH Plus showed the lowest flow (P<0.05). The initial and final setting time of AH Plus were lower than MTA Fillapex and TotalFill BC Sealer (P<0.05). In general, TotalFill BC Sealer presented higher Ca2+ ion release and pH than the other tested sealers. TotalFill BC Sealer also showed overall lower cytotoxicity when compared to the other sealers. Volumetric change of AH Plus and TotalFill BC Sealer was lower than MTA Fillapex (P<0.05). AH Plus, MTA Fillapex and TotalFill BC Sealer showed slight differences in the physicochemical properties and cytotoxicity, but all suitable for an endodontic sealer. However, AH Plus and TotalFill BC Sealer showed low volumetric changes when compared to MTA Fillapex

Evaluation of the use of heat-treated NiTi-alloy instruments with different tapers and kinematics in the biomechanical preparation of root canals with different anatomical shapes and sections

O objetivo dessa pesquisa foi avaliar, por meio de microtomografia computadorizada (micro-CT), as alterações morfológicas de canais radiculares com diferentes conformações e secções anatômicas, após o preparo biomecânico com instrumentos de liga de NiTi tratadas termicamente, e avaliar qualitativamente, por meio de microscopia eletrônica de varredura (MEV), a presença de debris dentinários. (1) Para o primeiro estudo, foram selecionados 30 incisivos inferiores humanos com canais radiculares achatados (razão diâmetro maior/menor &ge; 4) divididos em 5 grupos (n=10), G1: XP-endo Shaper, preparo seguindo as recomendações do fabricante; G2: XP-endo Shaper, com tempo de trabalho adicional de 30 segundos; G3: XP-endo Shaper, com movimento de pincelamento; G4: XP-endo Shaper, com movimento de pincelamento e tempo de trabalho adicional de 30s; e G5: Hyflex CM; sendo que os grupos G2 e G4 utilizaram a mesma amostra dos grupos G1 e G3, respectivamente. Para avaliação dos protocolos de irrigação final, os grupos 1, 3 e 5 foram submetidos a 3 diferentes protocolos: Sem irrigação (n=2); irrigação convencional com agulha e seringa (n=4), e irrigação com pressão negativa - Endo-Vac (n=4). Após o preparo, as amostras foram escaneadas em micro-CT e preparadas para avaliação de debris em MEV. Os dados quantitativos obtidos no micro-CT foram avaliados por meio do teste paramétrico ANOVA, seguido pelo pós-teste de Tukey, com nível de significância estatística estabelecido em 5%, e os dados qualitativos obtidos em MEV, foram comparados para estabelecer a concordância entre os examinadores através do teste Kappa. Observou-se que na análise dos protocolos de utilização do instrumento XP-endo Shaper, o tempo adicional não ocasionou diferença em nenhum dos parâmetros avaliados (p>0,05) em relação ao tempo preconizado pelo fabricante, independemente da cinemática empregada. Já na comparação ao instrumento Hyflex CM, o instrumento XP-endo Shaper em movimento de pincelamento apresentou as maiores médias de aumento de volume (p0,05). Já na análise qualitativa em MEV observou-se que o instrumento XP-endo Shaper, embora apresente movimento de chicoteamento no interior do canal radicular, foi capaz de propiciar a formação de batente apical assim como o instrumento manual, o que também foi observado em micro-CT. (3) Para o terceiro estudo, foram selecionados 40 molares inferiores humanos com canais mesiais curvos (ângulo: 25º - 50º; r &le; 4mm), divididos em 4 grupos (n=10) de acordo com o preparo biomecânico, G1: XP-endo Shaper (30/.04); G2: Hyflex CM (30/.04); G3: Reciproc Blue (25/.08) e G4: R-Motion (30/.04). Após o preparo, as amostras de cada grupo foram escaneadas em micro-CT para análise dos parâmetros bi e tridimensionais, bem como nível de espessura dentinária nas regiões de risco e segurança. Os dados quantitativos obtidos no micro-CT foram avaliados por meio do teste paramétrico ANOVA, seguido pelo pós-teste de Tukey, com nível de significância estatística estabelecido em 5%. Observou-se que o instrumento rotatório XP-endo Shaper e o instrumento reciprocante R-Motion foram capazes de realizar alterações na geometria do canal radicular em relação aos parâmetros avaliados de modo semelhante (p>0,05) aos instrumentos de maior conicidade, com semelhante número de paredes tocadas (p>0,05) e menores desgastes dentinários nas áreas de risco e segurança (p0.05) in relation to the time recommended by the manufacturer, regardless of the kinematics used. Compared to the Hyflex CM instrument, the XP-endo Shaper instrument in a brushing movement showed the highest mean volume increase (p0.05). Qualitative SEM analysis showed that the XP-endo Shaper instrument, although presenting whipping movement inside the root canal, was able to promote apical stop formation as well as the manual instrument, which was also observed in micro-CT. (3) For the third study, 40 human mandibular molars with curved mesial canals (angle: 25° - 50°; r &le; 4mm) were selected and divided into 4 groups (n=10) according to biomechanical preparation, G1: XP-endo Shaper (30/.04); G2: Hyflex CM (30/.04); G3: Reciproc Blue (25/.08) and G4: R-Motion (30/.04). After preparation, the samples from each group were scanned in micro-CT for analysis of two- and three-dimensional parameters, as well as dentin thickness level in the danger and safety regions. The quantitative data obtained in the micro-CT were evaluated using the parametric ANOVA test, followed by Tukey\'s post-test, with statistical significance level set at 5%. It was observed that the XP-endo Shaper rotary instrument and the R-Motion reciprocating instrument were able to make changes in the geometry of the root canal in relation to the parameters evaluated similarly (p>0.05) to the instruments with greater taper, with similar number of walls touched (p>0.05) and less dentin wear in the danger and safety areas (p<0.05). Therefore, according to the results obtained in these studies, it can be concluded that heat-treated NiTi-alloy instruments with different tapers and kinematics performed differently in root canals with different anatomical shapes and sections, indicating the need to plan an individualized biomechanical preparation on basis according to the anatomical characteristics of each dental group

Root canal preparation using micro-computed tomography analysis: a literature review

Abstract: This literature review has critically analyzed the published research related to the biomechanical preparation of root canals with three-dimensional analysis using micro-computed tomography (micro-CT). In December 2017, six databases (PubMed, Cochrane, Web of Science, Embase, Scopus, and Science Direct) were accessed using keywords to find articles including the use of the micro-CT analysis in biomechanical root canal preparation. There were 60 full articles that were selected, which were screened and read by two authors. The research that was reviewed and analyzed included root canal anatomy and sample selection, changes in canal shape and untouched canal areas, canal transportation and centering ability, and kinematics (motion). Of the studies selected, 49.18% discussed anatomical characteristics, with 54.1% of these studies describing mesial roots of mandibular molars with moderate curvature. Only 35% used a stratified distribution based on root canal system morphology and quantitative data obtained by micro-CT. The analysis of canal transportation and centering ability showed that transport values in the apical third exceeded the critical limit of 0.3 mm in mesial roots of mandibular molars with moderate curvature, especially in the groups in which a reciprocating system was used. In relation to kinematics, 91.70% of the reviewed studies evaluated continuous rotating instruments, followed by reciprocating rotation (38.33%), vibratory (15%), and the adaptive kinematics, which was in only 8.33%. The reciprocating kinematics was associated with higher canal decentralization and transportation indexes, as well as a greater capacity for dentin removal and debris accumulation. This literature review showed that the anatomy, the type of design and kinematics of instruments, and the experimental design are factors that directly influence the quality of biomechanical preparation of root canals analyzed in a qualitative and quantitative manner by micro-CT

Root canal preparation using micro-computed tomography analysis: a literature review

This literature review has critically analyzed the published research related to the biomechanical preparation of root canals with three-dimensional analysis using micro-computed tomography (micro-CT). In December 2017, six databases (PubMed, Cochrane, Web of Science, Embase, Scopus, and Science Direct) were accessed using keywords to find articles including the use of the micro-CT analysis in biomechanical root canal preparation. There were 60 full articles that were selected, which were screened and read by two authors. The research that was reviewed and analyzed included root canal anatomy and sample selection, changes in canal shape and untouched canal areas, canal transportation and centering ability, and kinematics (motion). Of the studies selected, 49.18% discussed anatomical characteristics, with 54.1% of these studies describing mesial roots of mandibular molars with moderate curvature. Only 35% used a stratified distribution based on root canal system morphology and quantitative data obtained by micro-CT. The analysis of canal transportation and centering ability showed that transport values in the apical third exceeded the critical limit of 0.3 mm in mesial roots of mandibular molars with moderate curvature, especially in the groups in which a reciprocating system was used. In relation to kinematics, 91.70% of the reviewed studies evaluated continuous rotating instruments, followed by reciprocating rotation (38.33%), vibratory (15%), and the adaptive kinematics, which was in only 8.33%. The reciprocating kinematics was associated with higher canal decentralization and transportation indexes, as well as a greater capacity for dentin removal and debris accumulation. This literature review showed that the anatomy, the type of design and kinematics of instruments, and the experimental design are factors that directly influence the quality of biomechanical preparation of root canals analyzed in a qualitative and quantitative manner by micro-CT.status: publishe