"I Concurso de Investigación, Proyectos de Intervención y de Emprendedurismo", evento académico desarrollado el 16 de diciembre de 2020 de manera virtual, Lima, Perú. Se presentaron los proyectos de intervención y de Emprendedurismo desarrollado por la comunidad de Odontología en UPC.. Ganador Segundo Puesto. / Evaluar in vitro el efecto antibacteriano y citotóxico de los extractos metanólicos de Phyllanthus niruri y Caesalpinia spinosa y la fusión de ambos sobre cepas de Enterococcus faecalis. (ATCC 29212).

Magister Chirurgiae Dentium (MChD) / The goal of root canal treatment is to eradicate microorganisms in the root canal system of the tooth. However; it has been found that no method of tooth preparation is efficient in eliminating all microorganisms present in root canals. Therefore, obturation materials with anti-microbial properties are advantageous, so that any residual microorganisms in the root system of the tooth can be eliminated. Therefore, the aim of the study was to assess the antimicrobial effect of 3 endodontic sealers: Sealapex™, EndoREZ™ and Guttaflow bioseal™ against Enterococcus faecalis. The Direct Contact test was used to assess the antibacterial effect of the 3 sealers against E. Faecalis. Sample size was n=50 per sealer. The survival of bacteria was assessed by culturing aliquots of 100 μL onto Tryptic Soy Agar plates after 10-fold serial dilutions. After incubation for 24 hours at 37⁰C, colonies on the plates were counted, and the CFU/mL was calculated. The experiments were performed in triplicates. Testing after setting enabled the assessment of the antimicrobial activity of aged sealers after 7 days, 14 days, 21 days and 28 days. All 3 sealers displayed evidence of antibacterial activity against E. Faecalis with various degrees of antibacterial activity at day 0, 7, 14, 21 and 28. Antibacterial activity was displayed by all 3 sealers against E. Faecalis which will have an effect on entombed bacteria.

Magister Scientiae Dentium - MSc(Dent) / Background: The primary goal of pulp therapy in the deciduous dentition is to keep the teeth fully functional in order to prevent arch space loss. A pulpectomy is a pulp therapy procedure indicated when an irreversibly inflamed or necrotic radicular pulp is encountered. ZOE and iodoform pastes (i.e. Kri 1 paste and Vitapex) have been recommended as root filling materials after pulpectomy. High clinical success rates have been reported with Vitapex and the fact that it resorbs readily when extruded beyond the apex is an added advantage. However, it has also been reported to resorb from within the root canals and even cause pathological root resorption in cases where the vital pulp is inflamed (Nurko et al., 2000). Iodoform-based preparations are thought to be more appropriate because they fulfill nearly all the requirements of the ideal root filling materials in primary teeth. Despite this, there are limited studies comparing the antibacterial effect of iodoform-based preparations. Aim: The aim of this study was to evaluate the antibacterial efficacy of Vitapex (V), Kri 1 paste (K) and pure iodoform (I) against E. faecalis.

This thesis deals with testing of antimicrobial activity of plant essential oils as part of packaging systems for foodpackaging against bacteria genus Enterococcus. The first literature part is focused on characteristic of genus Enterococcus and his possible apperace in food and his negative effect on human health. Next topic of literature section is targeted on using plants as producers of essential oils and their use in food industry as active compounds with antimicrobial and atifugal activity. This includes also characteristic of selected aromatic plants growing in our geographical conditions. Last part of literature section is introduction of characteristic of packaging materials and theirs big importance in food industry. Practical part of this thesis is dealing with testing of packaging materials containg essential oils on theirs surface against E. faecalis. Another part of this experiment is testing these antimicrobial packaging materials on selected foods in this case meat product following with microbiological analysis of selected bacteria.

Bacteria and fungi have acquired the ability to interact and survive in many hostile environments both found in nature, as well as, the human body. Candida albicans, an opportunistic fungal pathogen, causes a variety of infections in immunocompromised or immunosuppressed individuals, but also asymptomatically colonizes 80% of the population within the intestinal tract, oral cavity, as well as, the female genitourinary system. A unique capability of C. albicans is the ability to change its morphology from benign circular yeast form, to oval pseudohyphal form, to cylindrical tissue-penetrating hyphal form. Our laboratory has previously identified a bacterium, Alcaligenes faecalis, which displays inhibitory characteristics towards C. albicans. A review of the literature shows that some bacteria have the ability to inhibit C. albicans, but only when in the hyphal form. We therefore wanted to explore if the morphological state of C. albicans dictated the degree of inhibition A. faecalis is able to exude, or simply “does morphology matter?” To determine this effect, a series of both solid and liquid media experiments were performed using a wild-type (able to convert between morphologies) strain of C. albicans, a mutant strain of C. albicans locked into the yeast morphological state, and a mutant strain of C. ablicans locked into the hyphal morphological state. For solid media experiments, the different strains of C. albicans were made into a lawn on agar plates, A. faecalis was spotted onto the lawns, and, after 24 hours, observed for signs of inhibition. For liquid media experiments, C. albicans strains were inoculated alone or co-cultured with A. faecalis for 24 hours and plated to enumerate colony forming units. Our results indicate that: (1) the morphological state of C. albicans is not a determining factor, which is a unique finding compared to other published reports; (2) Both A. faecalis and the closely related A. viscolactis both inhibit C. albicans showing that this is a shared ability among the Alcaligenes genus. (3) that the ability to inhibit C. albicans is thru some form of contact dependent mechanism, as the cell free supernatant of A. faecalis has no inhibitory action. Currently, the exact mechanism for this interaction is unknown, but could be one of the secretion systems bacteria use for interactions with other microbes. As there are very limited treatments for fungal infections and severe side-effects associated with current antifungals, exploiting these mechanisms are medically relevant to human health as they could potentially lead to novel treatments for problematic human fungal pathogens.

The development and refinement of FA has been adequately investigated with major emphasis on pathogenic microorganisms. The development of this technique has reduced both the time and number of biochemical tests necessary to identify a diversity of organisms. The organisms included are the protozoans, as described by Goldman (1953 and 1957) and by Ingram (1961), viruses, as reported by Liu (1955a) and Burgdorfer and Lackman (1960a), pathogenic bacteria which have been investigated by Moody, Goldman, and Thomason (1956), Moody and Winter (1959), Deason, Falcone, and Harris (1957) and Thomason, Cherry, and Moody (1957). Various fungi have been studied with FA by Kaufman and Brandt (1964), Kaufman and Kaplan (1961 and 1963) and Gordon (1958). Therefore, due to the success of the fluorescent antibody technique in many areas of microbiology in previous investigations, the logical assumption was that immunofluorescence might be incorporated into an efficient system in which a specific organism associated with fecal pollution, such as S. faecalis, could be rapidly identified. Based on this assumption, the feasibility of fluorescent antibody techniques, using S. faecalis was investigated as a means of rapid determination of bacterial pollution in water. Although much progress has been achieved in the study of cytochemical reactions by immunofluorescence, no attention has been focused on the application of this method as a determinative tool by which water contamination, due to the presence of the enterococci, could be demonstrated. Specifically, the purpose of the research reported in this dissertation was to devise an applicable, valid, and rapid method that could be employed in the detection and identification of S. faecalis.

Enterococci are found in soil, sewage, food, water, and are commensal to the gastrointestinal tracts of mammals, insects, and birds. Enterococci often become nosocomial pathogens that cause a wide variety of diseases including urinary tract infections, endocarditis, and septicemia. These infections are often difficult to treat with antibiotics because most of the nosocomial strains are multi-drug resistant. Enterococcal plasmids function as reservoirs for resistance genes because they are extremely stable, allow for specific and efficient transfer, and can acquire resistance determinants from the chromosome and other plasmids. Additionally, enterococcal plasmids transfer across species boundaries transferring resistance genes like vancomycin to species like Staphylococcus aureus. There are two types of enterococcal plasmids, pheromone-responsive and broad host range. Pheromone-responsive plasmids are extremely stable, have a limited host range, and are primarily found in Enterococcus faecalis. Broad host range plasmids of E. faecalis and Enterococcus faecium are less stable than pheromone-responsive plasmids, but have an expanded host range into other Gram-positive species. E. faecalis has at least 25 known pheromone-responsive conjugative plasmids. One of the most extensively studied pheromone-responsive conjugative plasmids, pCF10. Conjugation of pCF10 from donor to recipient cell is induced by pheromone cCF10. cCF10 is contained within n the lipoprotein signal sequence encoded by the E. faecalis chromosomal gene ccfA. The lipoprotein signal sequence is processed by a series of proteolytic cleavage events to produce mature cCF10. Maturation of pheromone cCF10 produces three peptides: pre-cCF10 (CcfA1-22), cCF10 (CcfA13-19), and CcfA1-12. Cells containing pCF10 continue to produce cell membrane associated precursor pheromone of cCF10 (pre-cCF10), as well as, secreted and cell wall-associated cCF10. The presence of cCF10 does not self-induce conjugation by the donor cell because of two inhibitory molecules, PrgY and iCF10. Transmembrane protein PrgY is encoded by pCF10 and reduces cell wall associated cCF10, iCF10 is a pCF10 encoded inhibitory peptide (AITLIFI) that binds to PrgX, preventing cCF10 binding. While cCF10 controls pCF10 conjugation, pre-cCF10 controls host range of pCF10 by interacting with pCF10 replication initiation protein PrgW. cCF10 can initiate conjugation and mobilize the transfer of plasmids into other species, including Lactococcus lactis, but pCF10 cannot be maintained within the cell. However, if L. lactis is engineered to produce pre-cCF10, pCF10 can be maintained. The pre-cCF10 involvement in the establishment of pCF10 into other species might be related to the observation that it binds to the pCF10 replication initiation protein PrgW. By in vitro affinity chromatography experiments, interaction of cCF10 and pre-cCF10 with PrgW induced changes in PrgW mobility in gel electrophoresis that caused by formation of doublets and formation of aggregates which were thought to be mediated by disulfide bonds. Initial evidence of regulation of PrgW conformation by disulfide bonds was seen in Western blots of E. faecalis whole cell lysates where PrgW migration is sensitive to reduction. Sequence alignment comparisons between PrgW and a group of 54 of 59 known RepA_N superfamily proteins in E. faecalis revealed three highly conserved cysteines; these RepA_N proteins had a limited host range to E. faecalis. To study the importance of theses cysteines in pCF10 maintenance and host range limitation, prgW single, double, and triple cysteine to alanine (C to A) substitutions were generated. The cysteine mutant prgW was cloned into a plasmid functioning as either a contained the prgW alone (pORI10), or containing prgW with genes necessary for efficient pCF10 maintenance (pMSP6050). While all cysteine mutant plasmids of pORI10 and pMSP6050 were still capable of replicating in E. faecalis, the plasmid stability and copy number decreased, providing evidence that the cysteines were important to PrgW function. Additionally, Western blot analysis revealed PrgW C to A substitutions decreased PrgW aggregation. Mutations of PrgW cysteines reduced pMSP6050 stability and aggregation, but increased host range to L. lactis. Both L. lactis engineered to produce pre-cCF10 and the mutation of the conserved cysteines of PrgW extended host range of pMSP6050 into L. lactis. These data taken together with the observations that pre-cCF10 induced PrgW aggregation suggested that pre-cCF10 regulated the activity of the PrgW replication initiation protein through disulfide bonds. While the conserved cysteines of RepA_N proteins are found only in E. faecalis, phylogenetic analysis revealed that RepA_N homologs lacking the three cysteines are also found in E. faecium or S. aureus, suggesting that the host range of multiple plasmids might be affected by cysteine bond formation. Phylogenetic analysis also showed that the RepA_N proteins of enterococci and staphylococci appear to have evolved to determine host range based on the presence of two of the three conserved cysteines. Modular evolution of E. faecalis plasmids, like pCF10, that contained RepA_N proteins with three conserved cysteines, might have determined the fate of the plasmid as a limited host range, stable reservoir for antibiotic resistance. / Microbiology and Immunology

O objetivo deste estudo foi avaliar as propriedades físico-químicas, antimicrobianas e biocompatibilidade do MTA branco manipulado com extratos aquoso e/ou em propilenoglicol da Arctium lappa L., Casearia sylvestris Sw. e própolis. Dentre os testes físico-químicos foram avaliados o tempo de presa, escoamento, pH, liberação de íons cálcio e alteração volumétrica. Para verificar o efeito antimicrobiano foram aplicadas as metodologias do contato direto (Enterococcus faecalis e a Cândida albicans) e da descontaminação dentinária, empregando a microscopia confocal de varredura laser para verificar a viabilidade de Enterococcus faecalis. Para a avaliação da biocompatibilidade, 162 ratos Wistar foram utilizados, onde cada animal recebeu dois implantes subcutâneos e um alveolar. Após os períodos experimentais de 15, 30 e 60 dias foram realizadas análises microtomográfica, histológica descritiva e histomorfométrica. Adicionalmente amostras do tecido alveolar foram processadas para dosagem das citocinas TNF-&#x3B1; e IL-10 por meio do ensaio imunoenzimático (ELISA). Os dados obtidos foram analisados estatisticamente com os testes ANOVA e Tukey ou Kruskal-Wallis e Dunn. Os resultados revelaram que a variação do veículo associado ao MTA aumentou significativamente o tempo de presa, no entanto, não houve influência na alteração volumétrica (P>0,05) e na capacidade do cimento em manter o meio alcalino e liberar íons cálcio. Os cimentos manipulados com extratos em propilenoglicol apresentaram maior escoamento (P<0,05). Apenas o extrato da própolis agregou ao MTA efeito contra o Enterococcus faecalis após 24 e 48 horas (descontaminação dentinária e contato direto respectivamente) e contra a Cândida albicans após 10 horas (P<0,05). De acordo com as avaliações histológica e histomorfométrica dos implantes em tecidos subcutâneo e alveolar não foi constatada diferença significativa entre os grupos experimentais quando comparados com o grupo no qual o MTA foi manipulado com água destilada. Segundo a análise microtomográfica e a expressão das citocinas TNF-&#x3B1; e IL-10 houve similaridade (P>0,05) entre todos os grupos. Apesar de ter alterado algumas propriedades físico-químicas, o extrato da própolis potencializou o efeito antimicrobiano do MTA sem, contudo, alterar sua biocompatibilidade. / The aim of this study was to evaluate the physicochemical, antimicrobial properties and biocompatibility of white MTA mixed with aqueous or propylene glycol extracts of Arctium lappa L., Casearia sylvestris Sw. and propolis. Among physicochemical tests were evaluated the setting time, flowability, pH, ion calcium release and volumetric change. To verify the antimicrobial effects were applied the methods of direct contact (Enterococcus faecalis and Candida albicans) and dentin decontamination by using the confocal laser scanning microscopy to verify the Enterococcus faecalis viability. To evaluate the biocompatibility were used 162 Wistar rats. Each animal received one alveolar and two subcutaneous implants. After the experimental periods of 15, 30 and 60 days were performed the microtomography, histological description and histomorphometric analyses. Additionally alveolar tissue samples were processed for the measurement of TNF-&#x3B1; e IL-10 cytokines by enzyme-linked immunosorbent assay (ELISA). The data were statistically analyzed by the ANOVA and Tukey or KruskalWallis and Dunns tests. The results revealed that the variation of the vehicle associated to MTA significantly increased its setting time, however did not influence the volumetric change (P>0,05) and the cement\'s ability to maintain the alkaline medium and ion calcium release. Cements mixed with propylene glycol extracts showed higher flowability (P<0,05). Only propolis extract added to MTA the effect against E. faecalis after 24 and 48 hours (dentin decontamination and direct contact respectively) and against Candida albicans after 10 hours (P<0,05). According to the histological and histomorphometric evaluation of the implants in subcutaneous and alveolar tissue was not observed significant differences between the experimental groups in comparison to the reference group (MTA was mixed with distilled water). The microtomography analysis and expression of TNF-&#x3B1; and IL-10 showed that the groups were similar (P>0,05). Although the propolis extract modified some physicochemical properties of MTA it is potentiated the antimicrobial effect and did not influence the biocompatibility.

O objetivo deste estudo foi investigar o efeito da Terapia Fotodinâmica antimicrobiana (TFDa) sobre o Enterococcus faecalis (E. faecalis), in vitro, utilizando a clorofila (CL) como agente fotossensibilizador (FS) e o diodo emissor de luz (LED) como fonte de luz. A cultura pura de E. faecalis foi ativada em caldo de BHI a 37oC por 24h. O cultivo do microrganismo foi centrifugado a 3000rpm por 15min, e o pellet re-suspenso em 0,85% de solução salina. As concentrações da bactéria foram ajustadas para 107UFC mL-1 (unidades formadoras de colônias por mililitro). Diferentes tipos de solventes para a CL foram testados: éter, álcool de cereais, Tween 80 e P-123. 100l do inóculo e o mesmo volume da solução teste foram inseridos em cada poço da placa de microtitulação. A mistura foi agitada e aguardou-se 1min. 25l da suspensão foi removida e diluições seriadas foram realizadas. Alíquotas de cada diluição foram espalhadas na superfície da placa, armazenadas em microaerofilia e incubadas na estufa por 24h a 37oC. O número de UFC foi contado em cada placa. Para o experimento da TFDa, os grupos foram divididos em: controle (G1); TBO 1min (G2); CL+Tween 1min (G3); CL+Tween 5min (G4); CL+P-123 1min (G5); CL+P-123 5min (G6); CL+Tween 1min + LED 1min (G7); CL+Tween 1min + LED 5min (G8); CL+Tween 5min + LED 1min (G9); CL+Tween 5min + LED 5min (G10); CL+P-123 1min + LED 1min (G11); CL+P-123 1min + LED 5min (G12); CL+P-123 5min + LED 1min (G13); CL+P-123 5min + LED 5min (G14); TBO 1min + LED 1min (G15); TBO 1min + LED 5min (G16); LED 1min (G17); LED 5min (G18).Um volume de 100l da suspensão bacteriana foi inserido em poços da placa e o mesmo volume da solução do FS foi adicionado. A CL foi solubilizada em soluções aquosas de Tween ou P-123. Cada poço foi agitado e o tempo de préirradiação foi de 1 ou 5min. O LED foi acionado durante 1 ou 5min. 25l da suspensão foi submetida a diluições seriadas e as alíquotas de cada diluição foram espalhadas na superfície da placa em Ágar BHI. As placas foram armazenadas e colocadas na estufa a 37oC por 24h. Os experimentos foram realizados em triplicata e as UFC em cada placa foram contadas. As UFC foram transformadas em valores de Log10 UFC para normalizar os dados para análise estatística. A média e o desvio padrão (DP) de cada experimento foram calculados. Os resultados mostraram que o Tween e o P-123 foram os solventes mais eficazes para diluição da CL. A TFDa com utilização da CL diluída em Tween ou P-123 com tempo de pré-irradiação de 5min e com a ação do LED por 5min causou uma pequena diminuição na contagem bacteriana. A CL diluída em Tween com tempo de 1min teve uma redução significante da contagem bacteriana. O TBO quando associado ao LED durante 1min provocou uma leve redução no número de UFC. A irradiação pelo LED durante 5min foi capaz de causar uma diminuição significativa da quantidade de UFC. / The aim of this study was to investigate the effect of Antimicrobial Photodynamic Therapy (aPDT) against Enterococcus faecalis (E. faecalis), in vitro, using chlorophyll (CL) as photosensitizer (FS) agent and light-emitting diode (LED) as light source. Pure culture of E. faecalis was cultivated in BHI broth at 37oC for 24h. The culture was centrifuged at 3000rpm for 15min, and the pellets were resuspended in 0.85% saline solution. The bacterial concentrations were adjusted to 107CFU mL-1 (colony forming units per milliliter). Different types of solvents for CL were tested: ether, grain alcohol, Tween 80 and P-123. 100l of inoculum and the same volume of the test solution were inserted into each well of the microtitre plate. The mixture was mixed and 1 min was awaited. 25l of the suspension was removed and serial dilutions were performed. Aliquots of each dilution were spread on the surface of the plates, stored in microaerophilic conditions and incubated for 24h at 37oC. The number CFU was counted in each plate. For aPDT experiment, the groups were divided into: control (G1); TBO 1min (G2); CL+Tween 1min (G3); CL+Tween 5min (G4); CL+P-123 1min (G5); CL+P-123 5min (G6); CL+Tween 1min + LED 1min (G7); CL+Tween 1min + LED 5min (G8); CL+Tween 5min + LED 1min (G9); CL+Tween 5min + LED 5min (G10); CL+P-123 1min + LED 1min (G11); CL+P-123 1min + LED 5min (G12); CL+P-123 5min + LED 1min (G13); CL+P-123 5min + LED 5min (G14); TBO 1min + LED 1min (G15); TBO 1min + LED 5min (G16); LED 1min (G17); LED 5min (G18). A volume of 100l of bacterial suspension was inserted into the well of microtitre plate and the same volume of FS was added. CL was solubilized in aqueous solution of Tween and P-123. Each well was mixed and preirradiation time was 1 or 5min. LED was irradiated during 1 or 5 min. 25l of suspension was subjected to serial dilutions and aliquots of each dilution were spread on the surface of agar BHI plates. The plates were stored and incubated at 37oC for 24h. Experiments were performed in triplicate and CFU in each plate were counted. The results showed that Tween and P-123 were the most effective solvents for CL dilution. aPDT with diluted CL in Tween or P-123 with pre-irradiation time of 5min and with LED irradiation for 5min caused a small decrease in bacterial count. CL diluted in Tween with 1min time showed a significant reduction in bacterial count. TBO when associated with LED irradiation of 1min caused a slight reduction on CFU number. LED irradiation during 5min caused a significant reduction in CFU count.

O objetivo deste estudo foi comparar a capacidade de selamento apical de três materiais retrobturadores em dentes submetidos à infiltração microbiana por Enterococcus faecalis. Além de analisar a ocorrência da infiltração microbiana em relação à variável tempo. Para tal, foram utilizados 80 caninos superiores permanentes humanos extraídos, instrumentados com o sistema rotatório ProTaper Universal (MAILLEFER) e obturados pela técnica de compactação lateral, com dois tipos de cimento endodôntico: Endofill (DENTSPLY) e AH Plus (DENTSPLY). A apicetomia foi realizada com a remoção de 3mm do terço apical e o retropreparo confeccionado com pontas ultrasônicas. As amostras foram subdivididas, aleatoriamente, em 6 grupos com 10 dentes cada, e 2 grupos controles. Os materiais utilizados para a retrobturação foram MTA branco (ANGELUS), IBC BioAggregate (INNOVATIVE BIOCERAMIX INC.) e Acroseal (SEPTODONT). Foram confeccionados dispositivos para fixação dos dentes aos tubos Eppendorfs. As amostras foram inoculadas com cepas de E. faecalis e incubadas a 37C, por um período de 90 dias, para análise da presença de turvação do meio Enterococcosel. Para a realização da análise estatística foram utilizados os seguintes testes: Qui-quadrado com Prova Exata de Fisher e Kruskal-Wallis. Os resultados mostraram que todos os grupos nos quais foi realizada a obturação e a posterior retrobturação apresentaram infiltração. Comparando todos os grupos, não houve diferença significativa entre os materiais testados. Em relação apenas aos materiais retrobturadores, o Acroseal obteve a menor infiltração, seguido do MTA branco e do IBC BioAggregate. As amostras obturadas com o cimento Endofill não apresentaram diferença estatística em relação à variável tempo. Porém, nas amostras obturadas com o cimento AH Plus, houve maior ocorrência de infiltração nas amostras retrobturadas com o IBC BioAggregate e menor infiltração nas amostras retrobturadas com Acroseal, com diferença estatisticamente significante ao nível de 10%. / The objective of this study was to compare the apical sealing ability of three root-end filling materials in teeth submitted to the microbial leakage by Enterococcus faecalis. Besides analyzing the occurrence of the microbial leakage in relation to the variable time.For such, 80 canine permanent superior teeth extracted from humans were used, which were instrumented with ProTaper Universal system (MAILLEFER) and filled by the lateral compaction technique, with two types of endodontic sealers: Endofill (DENTSPLY) and AH Plus (DENTSPLY). The apices were resected with the removal of 3mm of the apical third and the root-end cavities prepared with ultrasonic tips. The samples were subdivided, randomly, in 6 groups with 10 teeth each, and 2 control groups. The materials used for the retrofilling were white MTA (ANGELUS), IBC BioAggregate (INNOVATIVE BIOCERAMIX INC.) and Acroseal (SEPTODONT). Devices were made for fixation of the teeth to the Eppendorf tubes. The filling samples were inoculated with strains of E. faecalis and incubated at 37C, for a period of 90 days, for analysis of the presence of turbidity of Enterococcosel medium. For the accomplishment of the statistical analysis the following tests were used: Qui-square with Exact Proof of Fisher and Kruskal-Wallis. The results showed that all the groups in which the filling was accomplished and the subsequent retrofilling presented leakage. Comparing all groups, there was not significant difference among the tested materials. In regard to only the root-end filling materials, Acroseal obtained the smallest leakage, followed by white MTA and IBC BioAggregate. The samples filled with the sealer Endofill didn't present statistical difference in relation to the variable time. However, in the samples filled with the sealer AH Plus, there was larger leakage occurrence in the samples retrofilled with IBC BioAggregate and smaller leakage in the samples retrofilled with Acroseal, with statistically significant difference at a 10% level.