Direct and transdentinal antibacterial activity of chlorhexidine.

PURPOSE: To evaluate the antibacterial effect of different chlorhexidine (CHX) concentrations against Streptococcus mutans using the agar-diffusion method with and without human dentin discs placed between the bacteria and the test substances. METHODS: For the direct application (agar-well technique), a base layer containing 15 mL of BHI agar and 300 microL of S. mutans inoculum (10(9) cfu/mL) was prepared in Petri dishes. Six wells per dish were made at equidistant points and immediately filled with CHX gels (0.12%, 0.2%, 1% and 2%), 35% phosphoric acid and pure natrosol (n = 6 wells/substance). Paper discs soaked in sterile distilled water served as control group (n = 6). For the indirect application (transdentinal diffusion), 0.2 mm- and 0.5 mm-thick human dentin discs (36 discs/thickness) had the hydraulic conductance determined, which allowed the homogeneous allocation of them to the experimental and control groups. The discs were placed at equidistant points on the Petri dishes containing BHI with the S. mutans inoculum (six discs per dish; one per substance) with the pulpal side in contact with the bacteria. In the discs treated with CHX gels, dentin surface was etched with H3PO4 and rinsed with distilled water before CHX gel application for 1 minute. After both direct and indirect application, the dishes were incubated for 24 hours and the bacterial growth inhibition zones formed around the wells and dentin discs were measured. Data were analyzed statistically by the non-parametric Kruskal-Wallis and Mann-Whitney tests at 5% significance level. RESULTS: In the direct test, all CHX concentrations presented a dose-dependent antibacterial activity against S. mutans. In the indirect test, there were statistically significant differences (P < 0.05) among all groups and the largest microbial growth inhibition zones were observed when 2% CHX was applied on 0.2 mm-thick discs (P < 0.05). It was concluded that all evaluated CHX gels exhibited both direct and transdentinal antibacterial activity against S. mutans. This effect of CHX was strongly influenced by the CHX concentration as well as the dentin barrier thickness.

Cytotoxicity of resin-based light-cured liners.

PURPOSE: To evaluate the cytotoxic effects of resin-based light-cured liners on culture of pulp cells. METHODS: Discs measuring 4 mm in diameter and 2 mm thick were fabricated from TheraCal (TCMTA), Vitrebond (VIT), and Ultrablend Plus (UBP). These specimens were immersed in serum-free culture medium (DMEM) for 24 hours or 7 days to produce the extracts. After incubating the pulp cells for 72 hours, the extracts were applied on the cells and the cytotoxic effects were determined based on the cell metabolism (MTT), total protein expression and cell morphology (SEM). In the control group, fresh DMEM was used. Data from MTT analysis and protein expression were submitted to Kruskal-Wallis and Mann-Whitney tests at the preset level of significance of 5%. RESULTS: When in contact with the 24-hour extract, TCMTA, VIT, and UBP decreased the cell metabolism by 31.5%, 73.5% and 71.0%, respectively. The total protein expressed by the cells in contact with VIT and UBP was lower than TCMTA and DMEM (Mann-Whitney, P < 0.05). When in contact with the 7-day extract, TCMTA, VIT, and UBP decreased the metabolic activity by 45.9%, 77.1% and 64.4%, respectively. All the liners expressed statistically lower amounts of proteins when compared to the control. A reduction in the number of cells was observed for all liners. The remaining cells from TCMTA group resembled those from the control group while for VIT and UBP the cells presented significant morphological alterations.

Transdentinal cytotoxic effects of different concentrations of chlorhexidine gel applied on acid-conditioned dentin substrate.

It has been demonstrated that chlorhexidine digluconate (CHX) is capable of eliminating bacteria that may remain lodged in dentin after mechanical caries removal. In addition, the use of CHX on acid-etched dentin before adhesive system application delays the resin-dentin interface degradation, maintaining the integrity of the adhesive restorations. Despite these advantages of using CHX in restorative dentistry, when applied on dentin, this chemical agent may diffuse across dentinal tubules to cause toxic effects to the pulp cells. The aim of this study was to evaluate the transdentinal cytotoxic effects caused by different concentrations of CHX gels applied on acid-conditioned dentin substrate. Dentin discs (0.2-mm and 0.5-mm thick) were cut from human third molars and mounted in artificial pulp chambers. Odontoblast-like MDPC-23 cells (50,000 cells/cm(2)) were seeded on the pulpal side of the discs, and the carbon polymer gel (natrosol) with different CHX concentrations (0.12, 0.2, 1, and 2%), 35% phosphoric acid, or pure natrosol were applied on the occlusal side of the discs, forming six treatment groups (n = 10 discs/thickness). The dentin discs in the control group (n = 10 discs/thickness) did not receive any treatment. In each group, cell metabolism was analyzed by the methyltetrazolium assay (n = 8/thickness), and cell morphology was assessed by scanning electron microscopy (n = 2/thickness). Statistical analysis showed that CHX gels had a dose-dependent toxic effect on the odontoblast-like cells. Cell metabolism decreased by 12.8, 14.6, 18.3, 26, 13.7, and 10.5% for the 0.5-mm-thick dentin discs and 23, 26.3, 28.1, 34.5, 22.5, and 19.4% for the 0.2-mm-thick dentin discs treated with 0.12% CHX, 0.2% CHX, 1% CHX, 2% CHX, H(3)PO(4), and pure natrosol, respectively. According to the experimental conditions of the current investigation, it may be concluded that the application of natrosol gel with different concentrations of CHX on acid-conditioned dentin causes mild transdentinal cytotoxic effects to the MDPC-23 cells in a dose-dependent manner. Dentin acted as a biological barrier against CHX diffusion, and this effect was directly related to dentin thickness.

Toxicity of chlorhexidine on odontoblast-like cells.

UNLABELLED: Chlorhexidine gluconate (CHX) is recommended for a number of clinical procedures and it has been pointed out as a potential cavity cleanser to be applied before adhesive restoration of dental cavities. OBJECTIVE: As CHX may diffuse through the dentinal tubules to reach a monolayer of odontoblasts that underlies the dentin substrate, this study evaluated the cytotoxic effects of different concentrations of CHX on cultured odontoblast-like cells (MDPC-23). MATERIAL AND METHODS: Cells were cultured and exposed to CHX solutions at concentrations of 0.06%, 0.12%, 0.2%, 1% and 2%. Pure culture medium (alpha-MEM) and 3% hydrogen peroxide were used as negative and positive control, respectively. After exposing the cultured cells to the controls and CHX solutions for 60 s, 2 h or 60 s with a 24-h recovery period, cell metabolism (MTT assay) and total protein concentration were evaluated. Cell morphology was assessed under scanning electron microscopy. CHX had a dose-dependent toxic effect on the MDPC-23 cells. RESULTS: Statistically significant difference was observed when the cells were exposed to CHX in all periods (p<0.05). Significant difference was also determined for all CHX concentrations (p<0.05). The 60-s exposure time was the least cytotoxic (p<0.05), while exposure to CHX for 60 s with a 24-h recovery period was the most toxic to the cells (p<0.05). CONCLUSION: Regardless of the exposure time, all CHX concentrations had a high direct cytotoxic effect to cultured MDPC-23 cells.

Cytotoxic effect of a 35% hydrogen peroxide bleaching gel on odontoblast-like MDPC-23 cells.

OBJECTIVE: This study evaluated transenamel and transdentinal cytotoxic effects of a bleaching gel on the MDPC-23 cell line. STUDY DESIGN: Discs obtained from bovine incisors were placed in a metallic device to simulate an in vivo pulp chamber. Groups were formed according to the enamel surface treatment: G1: 35% H(2)O(2) bleaching gel; G2: 35% H(2)O(2) bleaching gel + halogen light; G3: halogen light; and G4: control. Cell metabolism was evaluated by the methyltetrazolium assay and cell morphology by scanning electron microscopy. RESULTS: Cell metabolism decreased by 31.7%, 41.6%, and 11.5% in G1, G2, and G3, respectively. Cytotoxic effects observed in G2 were significantly more severe compared with G3 and G4. In G1 and G2, a smaller number of viable cells with major morphologic alterations remained adhered to dentin. CONCLUSION: The bleaching gel associated with light presented transenamel and transdentinal cytotoxic effects characterised by direct damage to odontoblasts and decrease of their metabolic activity.

Toxicity of chlorhexidine on odontoblast-like cells

Chlorhexidine gluconate (CHX) is recommended for a number of clinical procedures and it has been pointed out as a potential cavity cleanser to be applied before adhesive restoration of dental cavities. OBJECTIVE: As CHX may diffuse through the dentinal tubules to reach a monolayer of odontoblasts that underlies the dentin substrate, this study evaluated the cytotoxic effects of different concentrations of CHX on cultured odontoblast-like cells (MDPC-23). MATERIAL AND METHODS: Cells were cultured and exposed to CHX solutions at concentrations of 0.06 percent, 0.12 percent, 0.2 percent, 1 percent and 2 percent. Pure culture medium (á-MEM) and 3 percent hydrogen peroxide were used as negative and positive control, respectively. After exposing the cultured cells to the controls and CHX solutions for 60 s, 2 h or 60 s with a 24-h recovery period, cell metabolism (MTT assay) and total protein concentration were evaluated. Cell morphology was assessed under scanning electron microscopy. CHX had a dose-dependent toxic effect on the MDPC-23 cells. RESULTS: Statistically significant difference was observed when the cells were exposed to CHX in all periods (p<0.05). Significant difference was also determined for all CHX concentrations (p<0.05). The 60-s exposure time was the least cytotoxic (p<0.05), while exposure to CHX for 60 s with a 24-h recovery period was the most toxic to the cells (p<0.05). CONCLUSION: Regardless of the exposure time, all CHX concentrations had a high direct cytotoxic effect to cultured MDPC-23 cells.

Educação em saúde: efeito de um método de auto-instrução sobre os níveis de higiene oral em escolares / Health education: effect of a method for self- instruction on oral hygiene levels in schoolchildren

Objetivo: Verificar o efeito, sobre a higiene bucal de escolares, de um método de auto-instrução (gibi) aplicado com diferentes enfoques, avaliado em dois períodos. Método: A amostra foi composta de alunos da 2ª série do ensino fundamental, escolhidos aleatoriamente e agrupados em quatro grupos: grupo controle (G1) que não recebeu material algum, grupo leitura (G2) o qual recebeu o gibi e realizou-se sua leitura em sala de aula, grupo discussão (G3) que recebeu o gibi, e seu conteúdo foi lido e discuti do em sala de aula e grupo complete (G4) que recebeu o gibi e após a leitura foi orientado a reescrever a história. Como instrumento de avaliação utilizou-se o índice de placa de O'Leary, medido antes do programa e decorridos 30 dias. O índice de placa antes e decorridos 30 dias foi comparado, em cada grupo, por meio do Teste de Wilcoxon. O índice de placa dos diferentes grupos foi comparado por meio do Teste de Kruskal-Wallis, separadamente no momento antes e decorridos 30 dias. O nível de significância adotado foi de 5%. Resultados: Verificou-se uma diminuição estatisticamente significante (p<0,05) do índice de placa apresentado entre os dois períodos, nos quatro grupos estudados. Entretanto esta queda foi significativamente maior nos grupos com discussão e complete. Conclusão: A utilização do método de auto-instrução associado ao trabalho do seu conteúdo, como ocorreu no grupo discussão e complete propiciou um maior entendimento do assunto por ele transmiti do proporcionando maior queda dos índices de placa.

Objective: To identify the effect of a self-instructive method (comic strip), applied with distinct approaches and evaluated over two periods, on the oral health of schoolchildren. Method: The sample comprised 2nd year elementary schoolchildren chosen randomly and divided into four groups: a control group (G1) which received no material, a reading group (G2), which was given the comic strip and read it in the classroom, a discussion group (G3), who received the comic strip, which was read out loud in the classroom and discussed, and a complete group (G4), which received the comic strip and which, after reading it, was asked to rewrite the story. O'Leary's plaque index was used as an evaluation instrument, measured immediately prior to application of the program and again 30 days later. The plaque index measured after and 30 days was compared, in each group, using the Wilcoxon test. The plaque index of the diferents groups was compared using the Kruskal- Walis test, in two moments diferents. The significance level was 5%. Results: The results of the evaluation revealed a statistically significant reduction (p<0.05) of the plaque index presented between the two periods in the four groups studied here. However, this reduction was considerably greater in the discussion and complete groups. Conclusion: The use of the self-instruction method associated with work on its content, as occurred in the discussion and complete groups, led to a better understanding of the subject matter, resulting in a higher reduction of plaque indices.

Efeito citotóxico de um novo cimento de ionômero de vidro modificado porresina aplicado sobre células odontoblastóides / Cytotoxic effects of a current resin-modified glass-ionomer cement applied onodontoblast-like cells

O objetivo deste estudo foi comparar os efeitos citotóxicos do cimento de ionômero de vidro modificadopor resina VitrebondTM e da sua nova formulação VitrebondTM Plus quando aplicados em contatocom células de linhagem odontoblástica MDPC-23...

The aim of this study was to evaluate the cytotoxic effects of the resin-modified glass-ionomer liningcement VitrebondTM and its new formulation VitrebondTM Plus when applied to an immortalized odontoblast-cell line MDPC-23...

Efectividad de las técnicas rotatoria y oscilatoria en la preparación de conductos radiculares de conformación ovalada / Efetividade das técnicas rotatória e oscilatória no preparo biomecânico de canais radiculares de conformação ovalada / Effectiveness of root canal rotary and oscillatory peraparation techniques in flattened root canals

Este trabajo evaluó la preparación biomecánica de conductos radiculares de conformación ovalada, en cuanto al área de utilización de los instrumentos, se aplicaron cuatro técnicas: instrumentación oscilatoria con instrumentos de acero inoxidable Endo-Eze; instrumentación rotatoria con instrumentos de níquel-titanio del sistema Profile, instrumentación oscilatoria utilizando o sistema Profile, e instrumentación rotatoria con sistema Profile asociada a la instrumentación oscilatoria con sistema Endo-Eze. Fueron utilizadas 40 raíces distales de molares inferiores extraídos. Los especimenes fueron incluidos en resina poliéster cristal incolora, obteniendo un bloque con marcas en la porción externa. La raíz incluida en el bloque de resina fue seccionada de forma que pudiéramos visualizar la porción media del conducto radicular. Los dos cortes del bloque de resina fueron reposicionados, posibilitando la instrumentación de los conductos radiculares. Las imágenes de la superficie inferior de la sección media de cada raíz fueron obtenidas a través de una cámara digital y las imágenes archivadas. Después de la instrumentación, fueron realizadas nuevas fotografías. Las imágenes fueron transferidas para el programa AutoCAD, para que los conductos radiculares fueran trazados y la medición de las áreas de actuación de los instrumentos fuera realizada. Los resultados demostraron que no hubo diferencia estadísticamente significativa entre los grupos, aún haya sido observado un desgaste más uniforme en las paredes dentinarias por la instrumentación con los sistemas Profile y Endo-Eze asociados

This study evaluated the biomechanical preparation of flattened root canals, considering the effective area of instrumentation, using four different techniques: oscillatory instrumentation using Endo-Eze instruments; rotary instrumentation using Profile system; oscillatory instrumentation using Profile system; and rotary instrumentation with Profile system associated to oscillatory instrumentation with Endo-Eze system. A total of 40 distal roots of lower molars were used. These teeth were included in transparent resin blocks and grooves were made in the external portion of the block. The resin block containing the teeth was cut showing the median third of the root. Using a digital camera, the lower portion from the median third of the root were photographed, and the images recorded. After instrumentation, new images were obtained. The images were transferred to AutoCAD, the root canal was demarcated and the root canal area was measured. The results showed no statistically significant difference between the groups. However, a more uniform enlargement was observed in the group where oscillatory and rotary instrumentation were associated

Este trabalho avaliou o preparo biomecânico de canais radiculares de conformação ovalada, quanto à área de atuação dos instrumentos, utilizando quatro técnicas: instrumentação oscilatória com instrumentos de aço inoxidável Endo-Eze; instrumentação rotatória com instrumentos de níquel-titânio do sistema Profile, instrumentação oscilatória utilizando o sistema Profile, e instrumentação rotatória com sistema Profile associada à instrumentação oscilatória com sistema Endo-Eze. Foram utilizadas 40 raízes distais de molares inferiores extraídos. Os espécimes foram incluídos em resina poliéster cristal incolor, obtendo-se um bloco com marcas na porção externa. A raiz incluída no bloco de reina foi seccionada de forma a visualizarmos a porção média do canal radicular. Os dois cortes do bloco de resina foram reposicionados, possibilitando a instrumentação dos canais radiculares. As imagens da superfície inferior da secção média de cada raiz foram obtidas através de uma câmera digital e as imagens arquivadas. Após a instrumentação, foram realizadas novas fotografias. As imagens foram transferidas para o programa AutoCAD, para q os canais radiculares fossem traçados e a mensuração das áreas de atuação dos instrumentos fosse realizada. Os resultados demonstraram que não houve diferença estatisticamente significante entre os grupos, embora tenha sido observado um desgaste mais uniforme nas paredes dentinárias pela instrumentação com os sistemas Profile e Endo-Eze associados

O que provoca medo em crianças no consultório odontológico? / What can cause fear in children at the dental office?

Participaram do estudo 164 escolares que escreveram uma redação sobre suas experiências em consultório odontológico e identificaram em desenhos os instrumentais que provocavam mais medo. Após análise dos dados, constatou-se que a seringa carpule, a sonda exploratória e o micromotor foram os instrumentos mais citados pelas crianças como desencadeadores de medo, tanto por alunos de ensino particular (65,6 por cento, 54,7 por cento, 40,6 por cento respectivamente) quanto para as de ensino público (69 por cento, 54 por cento, 72 por cento). A palavra mais citada nas redações sob o ponto de vista positivo dos escolares foi dentista. Concluiu-se assim que, embora o instrumental de rotina no consultório ainda cause medo nas crianças, o Cirurgião-dentista representa o principal meio para amenizar e controlar o medo das crianças frente ao tratamento odontológico.

Conhecimento de saúde bucal em escolares: efeito de um método de auto-instrução / Oral health knowledge by schoolchildren: effect of a self-instruction method

Observou-se o comportamento de um método motivacional de auto-instrução sobre o conhecimento odontológico de escolares de 8 a 10 anos de idade. O método testado foi um gibi, cujo assunto relaciona-se a doenças bucais e à importância de sua prevenção. Os escolares foram divididos em grupos: leitura (GI) - entregou-se o gibi e realizou-se a sua leitura na sala de aula; discussão (GII) - feita a leitura do gibi, foi estimulada a discussão de seu conteúdo; e controle (GIII) - nãorecebeu material algum. O método de avaliação utilizado foi um questionário, aplicado antes (período A), imediatamente após (B) e decorridos 30 dias da administração do método (C). Os dados foram analisados estatisticamente por meio de estatistica descritiva e do teste de McNemar. Os resultados mostraram que, para o GI, houve diferença estatisticamente significante apenas referente à freqüência de escovação dos alunos quando comparados os momentos iniciais (A e B) e decorridos 30 dias(C). Para o GII, em A e B verificou-se uma melhora (p = 0,019) no conhecimento da doença periodontal. Pôde-se notar ainda, em todos os grupos, uma melhora da imagem positiva do cirurgião-dentista. Concluiu-se assim que, apesar de algumas questões terem apresentado diferençasestatisticamente significantes nos diferentes períodos e grupos, de um modo geral, o método testado não foi suficiente para a assimilação e sedimentação de conhecimentos relacionados à saúde bucal

An evaluation was made of how a motivational method of self-instruction influenced the knowledge of 8 to 10-year-old schoolchildren about oral health. The method consisted of a comic strip about oral diseases and the importance of their prevention. The children were divided into three groups: a reading group (GI) ­ the children received the comic strip as a classroom reading assignment; a discussion group (GII) ­ the comic strip was read out loud in the classroom and the children were encouraged to discuss its content; and a control group (GIII) ­ no reading material was distributed. The children's knowledge about oral health was evaluated through a questionnaire applied prior to (A), immediately after the reading and/or discussion of the content (B), and 30 days after application of the method (C). The data obtained by these procedures were statistically analyzed by relative frequency distribution and MacNemar test. The results for group GI indicated that there was no difference in the children's knowledge in situations A and B, while situation C showed a higher frequency of teeth brushing frequency. In group GII, there was an improvement from situation A to situation B in the children's knowledge about periodontal disease (p = 0.019). The children's knowledge about image of the dental professional improved positive in all groups. Hence, it was concluded that, although some aspects showed statistically significant differences between groups and situations, as a rule, the method evaluated here did not suffice for the children to satisfactorily assimilate and consolidate knowledge concerning oral health.

Atividade antibacteriana e citotoxicidade do agregado de trióxido mineral associado a diferentes concentrações de clorexidina / Antibacterial activity and cytotoxic effects of mineral trioxide aggregate associate with different concentrations of chlorhexidine

Para que um material seja indicado como retrobturador, é desejável que apresente várias propriedades, entre elas, intensa atividade antibacteriana e aceitável biocompatibilidade. O presente trabalho teve como objetivo avaliar, in vitro, o efeito antibacteriano e citotóxico do Agregado de Trióxido Mineral (MTA-Branco, Angelus® Indústria de Produtos Odontológicos Ltda., Londrina, PR, Brasil), associado à solução de clorexidina (CHX) em diferentes concentrações. Para a análise da atividade antibacteriana foi empregado o método de difusão em ágar Müller-Hinton e foram utilizados os microrganismos Staphylococcus aureus (ATCC - 25923), Pseudomonas aeruginosa (ATCC - 27853), Escherichia coli (ATCC - 25922) e Enterococcus faecalis (ATCC - 29262). Em placas de Petri contendo a suspensão bacteriana com meio de cultura, foram preparados poços com 4 mm de diâmetro e 5 mm de profundidade, os quais foram preenchidos com o cimento MTA preparado com água destilada estéril (G1-controle) ou com solução de CHX nas concentrações de 0,06% (G2), 0,12% (G3), 0,2% (G4) e 1% (G5). As placas foram incubadas em condições de aerobiose a 37ºC por 24 horas e os halos de inibição do crescimento bacteriano foram medidos em milímetros. Para avaliar a citotoxicidade do MTA associado às diferentes concentrações de CHX, o metabolismo e a morfologia celular foram avaliados por meio do teste do MTT e da análise da microscopia eletrônica de varredura, respectivamente. Corpos de prova de 4 mm de diâmetro e 2 mm de espessura foram preparados com as associações de materiais e imersos em 1,1 mL de meio de cultura (DMEM) por 24 horas ou por 7 dias para obtenção dos extratos. DMEM completo (grupo controle - G6) e os extratos de cada grupo foram aplicados sobre cultura de fibroblastos do ligamento periodontal de camundongos, os quais foram incubados por 24 horas a 37ºC com 5% de CO2 e 95% de ar. A adição de CHX 1% ao MTA aumentou a atividade antibacteriana do cimento sobre S. aureus (p<0,05). Para E. coli e P. aeruginosa não houve diferença estatística em relação aos tamanhos dos halos de inibição para todos os materiais estudados (p>0,05). Para o E. faecalis, MTA + CHX 0,2% e MTA + CHX 1% apresentaram menores halos de inibição quando comparados aos demais grupos (p<0,05). Para os extratos de 24 horas, a redução do metabolismo celular para os grupos G1 a G5 foi de 11,87%; 23,63%; 21,87%; 34,64% e 83,01%, respectivamente; para os extratos de 7 dias, o metabolismo das células decresceu em 61,35%; 71,45%; 75,43%; 81,26% e 86,13%, respectivamente. Para ambos os períodos de obtenção dos extratos e para todos os grupos experimentais, o metabolismo celular foi estatisticamente menor do que para o grupo controle (G6) (p<0,05). O menor efeito citotóxico foi observado para G1 (p<0,05), seguido pelos grupos G2 e G3 que não apresentaram diferença estatisticamente significante entre si (p>0,05). Os grupos G4 e G5 apresentaram os maiores efeitos citotóxicos, sendo G5 mais citotóxico do que G4 (p<0,05). Concluiu-se que: 1) a adição de clorexidina ao MTA independente da concentração utilizada, não resultou em melhora da atividade antibacteriana sobre as espécies estudadas, com exceção do S. aureus; 2) quanto maior a concentração de CHX incorporada ao pó do MTA, maior a toxicidade do cimento sobre fibroblastos do ligamento periodontal de camundongos (MDPL); 3) o extrato de 7 dias foi mais citotóxico que o extrato de 24 horas

An ideal root-end filling material should present several properties, including antibacterial activity and biocompatibility. The aim of this in vitro study was to investigate the antibacterial and cytotoxic effects of Mineral Trioxide Aggregate (MTA-White, Angelus® Indústria de Produtos Odontológicos Ltda., Londrina, PR, Brasil) mixed with different concentrations of chlorhexidine (CHX). For antibacterial activity analysis diffusion method on Müller-Hinton agar was employed. The bacterial strains used were Staphylococcus aureus (ATCC - 25923), Pseudomonas aeruginosa (ATCC - 27853), Escherichia coli (ATCC - 25922) e Enterococcus faecalis (ATCC - 29262). In Petri plates containing culture medium with bacterial suspension, wells were made measuring 4 mm in diameter and 5 mm in depth. The wells were completely filled with MTA mixed with sterile distilled water (G1) or with different concentrations of CHX: 0.06 % (G2), 0.12% (G3), 0.2% (G4) and 1% (G5). The plates were incubated in aerobic conditions at 37ºC for 24 hours, and then the diameters of the zones of bacterial inhibition were measured. To evaluate the cytotoxicity of the MTA mixed with different concentrations of CHX, the cell metabolism and cells morphology were evaluated by the MTT assay and scanning electron microscopy, respectively. Round-shaped samples measuring 4 mm in diameter and 2 mm in thickness were prepared with the association of materials and immersed in 1.1 mL of culture medium (DMEM) and incubated for 24 hours or 7 days. The extracts from every sample and pure DMEM (control group - G6) were applied on mouse periodontal ligament fibroblast cells culture and incubated at 37ºC with 5% CO2 and 95% air for 24 hours. The addition of CHX 1% to MTA increased the antibacterial activity of the cement against S. aureus (p <0.05). There was no statistically significant difference in size of inhibition zones against E. coli and P. aeruginosa for the studied materials (p> 0.05). Against E. faecalis, MTA + CHX 0.2% and MTA + CHX 1% determined lower inhibition zones when compared to the other groups (p <0.05). To 24-hour extracts the reduction of cell metabolism was 11.87%; 23.63%; 21.87%; 34.64%; and 83.01%, respectively for groups G1 to G5. To 7-day extracts, the metabolism of the cultured cells decreased by 61.35%; 71.45%; 75.43%; 81.26%; and 86.13% respectively for groups G1 to G5. For both periods of extracts obtained and for all experimental groups, the cell metabolism was significantly lower than in control group (G6) (p<0.05). The lowest cytotoxic effect was observed for G1 (p<0.05) followed by G2 and G3 groups that did not show a statistically significant difference between them (p>0.05). The groups G4 and G5 had the higher cytotoxic effects and G5 was more cytotoxic than G4 (p<0.05). It was concluded that: 1) the addition of chlorhexidine to MTA independent of the concentration used did not improve the antibacterial activity against studied microorganisms (except against S. aureus); 2) all concentrations of chlorhexidine mixed with MTA caused intense cytotoxic effects when extracts obtained in both periods were applied directly on mouse periodontal ligament fibroblast cells (MDPL); 3) the extract of 7 days was more cytotoxic than the extract of 24 hours