Resumo Este estudo laboratorial avaliou por meio de micro-CT a eficiência do uso de um único instrumento de três sistemas rotatórios em retratamentos endodônticos, comparados a um instrumento único reciprocante. Sessenta caninos extraídos foram preparados usando o sistema ProTaper Universal (F2) e obturados. Após 30 dias de armazenamento a 37 ºC e 100% de umidade, os dentes foram divididos aleatoriamente em quatro grupos (n = 15), de acordo com o instrumento utilizado para remover as obturações endodônticas: ProTaper NEXT (PTN), ProTaper Gold (PTG), TRUShape 3D (TS) e WaveOne (WO). Os canais foram retratados usando apenas o instrumento tamanho 40 de cada sistema, seguindo as recomendações do fabricante para torque e velocidade. O tempo necessário para remover a obturação foi registrado em segundos. A quantidade de material remanescente e o volume de dentina removida foram avaliadas por meio de micro-CT. Análise estatística foi realizada (ANOVA e Kruskal-Wallis), com nível de significância de 5%. O tempo de trabalho no grupo TS foi significativamente maior (p<0.05) (média, 384,80 ± 144,92) comparado a WO (229,67 ± 68,16) e PTG (248,67 ± 64,22), e similar a PTN (327,67 ± 133,3). Não houve diferenças entre os grupos na quantidade de dentina removida e nas porcentagens de material obturador residual. O uso de apenas um instrumento rotatório dos sistemas PTG, TS e PTN foi tão eficaz quanto o do sistema WO reciprocante na remoção do material obturador. No entanto, nenhum dos instrumentos conseguiu remover completamente os materiais obturadores.

Abstract This study evaluated the efficiency of using a single instrument from three different rotary multi-file systems and compared them with that of a reciprocating single-file for endodontic retreatment by means of micro-CT. Sixty extracted canines were prepared using a size F2 ProTaper Universal file and obturated. After 30 days of storage at 37ºC and 100% humidity, the teeth were randomly divided into four groups (n=15) based on the type of instrument used to retreatment: ProTaper Next (PTN), ProTaper Gold (PTG), TRUShape 3D (TS), and WaveOne (WO). The canals were retreated using only the size 40 instrument from each system according to the manufacturer’s recommendations for torque and speed. The time required to remove the filling material was recorded in seconds. The amount of initial and residual filling material and the quantity of dentin removed were assessed by means of micro-CT. Data were statistically analyzed (ANOVA and Kruskal-Wallis) at a 5% significance level. TS instruments required the highest (p<0.05) amount of time (mean, 384.80 ±144.92) compared with the WO (229.67±68.16) and PTG (248.67±64.22) and not so different from PTN instruments (327.67±133.3). No differences in the amount of dentin removed, initial and residual filling volume, and percentages of filling material were observed among the groups. The use of a single rotary instrument from the PTG, TS, and PTN systems was as effective as that of the single-file reciprocating WO system. However, none of the instruments was able to remove the filling materials completely.

Resumo Introdução O MTA é um importante material de uso na odontologia, com boas propriedades biológicas. As respostas experimentais aos cimentos endodônticos que utilizam este composto no selamento e preenchimento do sistema de canais radiculares, aliados a uma boa instrumentação e limpeza, podem ser importantes no processo de reparo periapical. Objetivo Avaliar in vitro a profundidade de penetração de dois diferentes cimentos endodônticos nos túbulos dentinários e a infiltração bacteriana em obturações com os cimentos AH Plus e MTA Fillapex. Material e método 34 pré-molares monorradiculados humanos foram selecionados, suas coroas removidas e suas raízes padronizadas em 16 mm, a seguir foram, então, divididos aleatoriamente em dois grupos de 15 espécimes e instrumentados com o sistema rotatório Pro Taper. Um grupo foi obturado com o cimento AH Plus (Grupo AH) e outro com MTA Fillapex (Grupo FI). Nestes grupos, avaliaram-se a infiltração coronária de bactérias para Enterococcus Faecalis e a profundidade de penetração nos túbulos dentinários. Para a aferição da infiltração bacteriana, usou-se o teste exato de Fisher; para a penetração intratubular, usou-se o teste-t. Resultado Para a infiltração bacteriana, considerando o número de amostras infiltradas para AH e MTA Fillapex, houve diferença estatística significativa (p=0,0341). Na avaliação da penetração intratubular, a diferença entre os dois grupos de cimentos foi considerada estatisticamente significativa (p=0,0006). Conclusão Ambos os cimentos apresentaram infiltração bacteriana, sendo que o MTA Fillapex teve pior desempenho. A capacidade de penetração nos túbulos dentinários do AH Plus foi significativamente maior que a do MTA Fillapex.

Abstract Introduction The MTA is an important use in dentistry material with good biological properties. The experimental responses to sealers using this compound in the sealing and filling of the root canal system, combined with a good instrumentation and cleaning, may be important in the periapical healing process. Objective To evaluate in vitro penetration depth of two different sealers in dentinal tubules and bacterial infiltration in fillings with AH Plus and MTA Fillapex cements. Material and method 34 premolars human monorradiculados were selected, their removed and their standardized root crowns in 16mm, after then randomly divided into two groups of 15 specimens, and instrumented with rotary system Pro Taper. One group was obturated with cement AH Plus (group HA) and another MTA Fillapex (FI Group). These groups are evaluated for coronary infiltration of bacteria Enterococcus faecalis and the depth of penetration in the dentinal tubules. For the measurement of bacterial infiltration used Fisher's exact test for Intratubular penetration we used the t-test. Result For bacterial infiltration, considering the number of infiltrated samples AH and MTA Fillapex, there was a statistically significant difference (p = 0.0341). In the evaluation of intratubular penetration, the difference between the two groups of cement was statistically significant (p = 0.0006). Conclusion Both cements showed bacterial infiltration and the MTA Fillapex had worse performance, capabilities to enter the dentinal tubules AH Plus was significantly higher than the MTA Fillapex.

Objective: To analyze possible correlations among tubular dentine cement penetration, adhesiveness and apical leakage in fillings performed with gutta percha and an endodontic cement based on epoxy amine resin. Material and Methods: Sixty similar, extracted human mandibular central incisors were irrigated, instrumented and filled following the same protocol. First, apical leakage was quantified by fluid filtration tests. Then, these same specimens were sectioned for analysis of tubular dentine cement penetration and the middle thirds were submitted to push-out tests to analyze the adhesiveness of the fillings. Results: In brief, the means and standard deviations with a confidence interval of 95% were as follows: tubular dentine cement penetration (8.875±4.540), adhesiveness (4.441±2.683) and apical leakage (0.318±0.215). The data were confronted using the Pearson's test (P>0.05), and it was possible to prove that there was no correlation between (1) tubular dentine cement penetration and apical leakage (r2: 0.08276), (2) tubular dentine cement penetration and adhesiveness (r2: -0.2412) and (3) adhesiveness and apical leakage (r2: 0.1340). Conclusion: After analysis of these data, it could be observed that there exists no correlation among the variables analyzed in this study.

The aim of this paper was to evaluate a possible correlation between obturation limits and leakage. Thirty-six extracted human mandibular incisors were used, characterized by straight and single canals, non-anatomical complexities, absence of previous endodontic treatment, complete root formation and patent foramen. For standardization of the specimens for the leakage analysis, foraminal instrumentation was performed up to a Flexofile #25 (Dentsply-Maillefer, Ballaigues, Switzerland). All specimens were instrumented and filled following the same protocol, and the obturation limits were measured using Axiovision 4.5 Software (Carl Zeiss Vision, Hallbergmoos, Germany). The specimens were then separated into three groups (n = 12) according to the following variables: Group I - obturation limits ranging from 0 mm to 0.76 mm of the main apical foramen. Group II - obturation limits ranging from 0.77 mm to 0.98 mm of the main apical foramen. Group III - obturation limits ranging from 0.99 mm to 1.68 mm of the main apical foramen. Apical leakage was quantified by fluid filtration. The analyses were confronted using Pearson's test (p > 0.05). Groups I, II and III showed Pearson correlation values (r2) of -0.152, -0.186 and 0.058, respectively. No correlation was found between the obturation limits and apical leakage

Avaliou-se, in vitro, a capacidade seladora, do MTA-Angelus, ProRoot-MTA, Super-EBA e MBP-c, quando utilizados para selar perfurações na região de furca de molares humanos extraídos; quando aplicados isoladamente ou em associação com uma matriz de gesso Paris, aplicada no fundo do trajeto da perfuração. O selamento produzido pelos materiais foi analisado por meio da infiltração do corante rhodamine B 0,2%. A análise estatística aplicada aos dados obtidos demonstrou que, quando utilizado isoladamente (sem matriz), o cimento MBP-c apresentou os menores índices de infiltração marginal, seguido pelo Super-EBA, apresentando diferença estatística significante (p< 0,001) entre esses e os cimentos ProRoot-MTA e MTA-Angelus. Na presença da matriz, o cimento MBP-c também foi superior, havendo diferença estatística significante (p<0,05) entre ele e os cimentos ProRoot-MTA e MTA-Angelus. A aplicação da matriz de gesso Paris influenciou negativamente a capacidade seladora dos cimentos Super-EBA e MBP-c; inclusive, com diferenciação estatística (p<0,05), contudo, ela evitou o extravasamento dos materiais seladores.

It has been evaluated in vitro the sealing capacity of MTA-Angelus, ProRoot-MTA, Super-EBA and MBP-c when sealing furcal perforations of extracted human molars. The experiment took place with materials both isolated as well as in association with a plaster of Paris matrix applied at the bottom of the perfuration path. The materials sealing capacity was analyzed by dye leakage of rhodamine B 0,2%.The statistical analysis revealed that when isolated and tested (without the matrix), the cement MBP-c presented the smallest coefficient of marginal leakage, followed by the Super-EBA. There was a statistical significance between those and the cements ProRoot - MTA e MTA - Angelus (p<0,001). In the presence of the matrix, the cement MBP-c also had a superior performance having statistical significance between those and the cements ProRoot - MTA e MTA - Angelus (p<0,05); The Plaster of Paris matrix had a negative impact with statistical significance regarding the sealing capacity of the cements Super-EBA and the MBP-c (p<0,05). Nevertheless, it avoided the leakage of the respective sealing materials.