Made available in DSpace on 2014-08-20T14:30:16Z (GMT). No. of bitstreams: 1 Dissertacao_Laura_Siqueira_Pintado.pdf: 1321397 bytes, checksum: a54cf33fb1a88d6f8f068fcdad1d0588 (MD5) Previous issue date: 2011-08-26 / Aiming at the success of conservative pulp treatment, the MTA (mineral trioxide aggregate) has been considered the first choice product for performing direct pulp capping. It has features such as biocompatibility, ability to stimulate the formation of dentin and cellular proliferation, among others. However, drawbacks such as difficulty of handling after the manipulation and extended setting times stimulated new researches in an attempt to improve such characteristics. Thus, a light-cured cement-based MTA was developed at the CDC-BIO in the Faculty of Dentistry of the Federal University of Pelotas. It is suggested that the presence of resin monomers may have a deleterious effects on the dental pulp. Based on this fact, the study evaluated the cytotoxicity and genotoxicity of the experimental MTA compared with the conventional commercially available as well as their physical and mechanical properties. Primary cultures of human pulp fibroblasts (HPF) and one strain of mouse fibroblasts 3T3/NIH were employed. Pulp of extracted sound human third molars was used for the pulpal fibroblast cell culture. Specimens were made from the two materials and embedded in 1 mL of DMEM for obtaining the test eluate. For cytotoxicity, cells were incubated for 24 or 48 hours with the eluate and evaluated by the MTT assay [3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide]. To assess the genotoxicity of the products through micronucleus development the Feulgen staining technique was employed after cell incubation for 24 hours with the eluate. For the evaluation of physical and mechanical properties of the experimental MTA diametral tensile strength and sorption and solubility tests were performed. The results were analyzed by ANOVA and Kruskal Wallis tests considering p <0.05. The light-curing MTA showed cytotoxic effects similar to conventional MTA in the two cell lineages. The percentage of micronuclei was different between the materials, but both were similar to control. The diametral tensile strength was lower for the experimental MTA. The conventional MTA was more soluble and both had the same behavior in relation to water sorption. The results suggest that the experimental light-cured MTA had similar behavior and biocompatibility comparable to the commercially available MTA and is a promising material for pulp capping / Visando o sucesso do tratamento conservador da polpa, o MTA (agregado trióxido mineral) tem sido considerado o produto de primeira escolha para a realização de capeamento pulpar direto. Apresenta características como biocompatibilidade, capacidade de estimular a formação de dentina e proliferação celular, entre outros. No entanto, os inconvenientes como a dificuldade de manuseio após a manipulação e longo tempo de presa tem estimulado novas pesquisas na tentativa de melhorar essas características. Assim, um novo cimento fotopolimerizável baseado em MTA (MTA F) foi desenvolvido na Faculdade de Odontologia da Universidade Federal de Pelotas. Sugere-se que a presença de monômeros resinosos pode ter um efeito deletério sobre a polpa dentária. Baseado neste fato, o estudo avaliou a citotoxicidade e genotoxicidade do MTA F em comparação ao convencional disponível no mercado bem como suas propriedades físico-mecânicas. Foram utilizadas culturas primárias de fibroblastos de polpa humana (FPH) e uma linhagem de fibroblastos de camundongo 3T3/NIH. Polpa extraída de terceiros molares humanos íntegros foi utilizada para a cultura de fibroblastos pulpares. Os corpos de prova de ambos os materiais foram embebidos em 1 mL de DMEM para a obtenção do eludato teste. Para citotoxicidade, as células foram incubadas por 24 ou 48 horas com o eludato e avaliado pelo ensaio de MTT [3 - (4,5-dimetil-2-il) -2,5-brometo difeniltertrazolim]. Para avaliar a genotoxicidade dos produtos através da técnica de micronúcleos, foi utilizada a técnica de coloração de Feulgen após a incubação de células por 24 horas com o eludato. Para a avaliação das características físico-mecânicas do MTA experimental foram realizados os testes de resistência a tração diametral e sorção e solubilidade. Os resultados foram analisados pelos testes ANOVA e Kruskal Wallis considerando p<0,05. O MTA fotopolimerizável apresentou efeitos citotóxicos semelhantes ao MTA convencional nas duas linhagens celulares. O percentual de micronúcleos foi diferente entre os materiais, porém ambos foram semelhantes ao controle. A resistência a tração diametral do MTA experimental foi inferior ao MTA comercial. O MTA convencional foi mais solúvel e ambos tiveram o mesmo comportamento em relação à sorção de água. Os resultados sugerem que o MTA experimental fotopolimerizável teve comportamento e biocompatibilidade semelhante ao MTA disponível comercialmente, sendo um material promissor para o capeamento pulpar

En Europe de l’Ouest et tout particulièrement dans le Sud-Ouest de la France, la période comprise entre environ 60 et 40 mille ans avant le présent est marquée par une mosaïque de changements culturels et démographiques. L’étude des industries lithiques montre que les derniers groupes néandertaliens semblent avoir diversifié leurs comportements techniques juste avant de disparaître. Les industries dites de « transition »,notamment le Châtelperronien, sont souvent considérées comme l’aboutissement d’une trajectoire d’évolution technique néandertalienne. Cependant, notre compréhension des différentes industries du Moustérien récent, de leur chronologie, de leur organisation et de leur succession, ainsi que de leurs liens potentiels avec l’émergence du Paléolithique supérieur, est rendue infiniment complexifiée par, d’une part, le recours à des collections anciennes provenant de fouilles parfois réalisées il y a plus d’un siècle, et, d’autre part, l’absence de révision critique de certaines séquences clés. Ce travail présente une étude techno-typologique et taphonomique des industries lithiques de plusieurs niveaux majeurs de l’Abri inférieur du Moustier, sur la base d’une révision des collections anciennes mais aussi de l’analyse de matériel issu de la reprise récente des fouilles dans ce gisement de référence. Les résultats acquis au Moustier, combinés avec une révision critique de l’association présumée entre industrie châtelperronienne et restes humains néandertaliens à Saint-Césaire, soulèvent d’intéressantes questions sur les modalités de définition des techno-complexes lithiques et sur notre perception des conditions de la disparition des Néandertaliens. / During the period between broadly 60 ky and 40 ky Western Europe, and especially south-western France, was the theatre for a mosaic of bio-cultural changes. Late Neanderthal groups appeared to have diversified their lithic technology just prior to disappearing. This technological trajectory is commonly seen as culminating in the so-called ‘transitional ‘industries, notably the Châtelperronian. However, our understanding of the chronology, organisation and succession of the Late Mousterian and its possible relation to the emergence of the Upper Palaeolithic in this region is complicated due to the reliance on sites excavated sometimes as longas a century ago combined with the absence of a critical appraisal of certain key sites. This thesis presents arevision of previously recovered and newly excavated material from several important levels of Le Moustier(Lowe Shelter). When considered in light of a revision of the Châtelperronian-Neandertal association at Saint-Césaire, these results pose interesting questions for the definition of lithic techno-complexes and how we view the complex question of Neandertal extinction/replacement.

Made available in DSpace on 2014-08-20T14:30:08Z (GMT). No. of bitstreams: 1 Dissertacao_giane_silva_linhares.pdf: 488926 bytes, checksum: 2a1b87dca9f0a74faf913e8c6e40713e (MD5) Previous issue date: 2012-12-05 / The incorporation of light-curable resins has been proposed for Mineral Trioxide Aggregate (MTA) to improve its properties and reduce its setting time. The aim of the present study was to assess the pH, calcium-ion release and antibacterial activity of an experimental dual-cure Bis-EMA/MTA-based root-end filling material (E-MTA) in comparison with white-MTA (W-MTA); and to evaluate the influence of the addition of CaCl2 on these properties. Polyethylene tubes filled with the materials were immersed in deionized water for the measurement of pH (digital pH meter) and calcium release (atomic absorption spectrophotometry). The evaluations were performed at 3 and 24 hours and 7, 15 and 30 days. The direct contact test was used for evaluation of antibacterial activity of the materials against E. faecalis 30 min and 24 h after manipulation. All materials presented a variation from an alkaline to nearly neutral pH, and were capable of releasing calcium ions along the 30 days of the study. E-MTA showed a significant lower calcium ion release capacity when compared to W-MTA (P<0.05). The calcium release of E-MTA + 5% CaCl2 was similar to W-MTA (P> 0.05). All materials were 100% effective against E. faecalis at 30 min after manipulation. Reduction in the antibacterial activity was observed for E-MTA with or without the addition of CaCl2 after 24h. The monomer Bis-EMA added to MTA formed a material with lower capacity of calcium release and lower antibacterial activity than W-MTA, in spite of maintaining a similar pH. However, the addition of CaCl2 improved the calcium release of this material / A incorporação de resinas fotopolimerizadas ao agregado de trióxido mineral (MTA) tem sido proposta com o intuito de melhorar as suas propriedades e reduzir o tempo de presa. O objetivo do presente estudo foi avaliar o pH, a liberação de íons cálcio e a atividade antibacteriana de um material retrobturador experimental de polimerização dual a base de Bis-EMA/MTA (MTA-E) em comparação com o MTA-branco (MTA-B); e avaliar a influência da adição de CaCl2 sobre estas propriedades. Tubos de polietileno com os materiais foram imersos em água deionizada. Para medir o pH da água foi utilizado um peagâmetro digital. O cálcio liberado foi determinado pela técnica de espectrometria de absorção atômica. O Teste do Contato Direto foi utilizado para avaliar a atividade antibacteriana dos materiais contra E. faecalis 30 min e 24 h após a manipulação. Todos os materiais apresentaram uma variação de pH de alcalino para quase neutro e foram capazes de liberar íons cálcio durante os 30 dias do estudo. MTA-E mostrou uma capacidade de liberação de íons cálcio significativamente menor que o MTA-B (P<0,05). A liberação de cálcio do MTA-E + CaCl2 5% foi semelhante ao MTA-B (P>0,05). Todos os materiais foram 100% efetivos contra E. faecalis nos 30 minutos após a manipulação. Após 24h uma redução na atividade antibacteriana foi observada para o MTA-E, com ou sem a adição de CaCl2. O monómero Bis-EMA adicionado ao MTA formou um material com baixa capacidade de liberação de cálcio e menor atividade antibacteriana do que MTA-B, apesar de manter um pH semelhante. No entanto, a adição de CaCl2 melhorou a liberação de cálcio deste material

Objetivo: Avaliar se a adição de nanopartículas de prata ao cimento MTA branco irá melhorar a ação antimicrobiana sobre Enterococcus faecalis e prevenir a aderência deste microrganismo ao material. Método: Teste de contato direto utilizando corpos de prova dos materiais: MTA branco (n=10) grupo B, MTA cinza (n=10) grupo C, MTA branco + NPAg em pó a 1% em peso (n=10) grupo P, MTA branco + solução de NPAg 50ppm (n=10) grupo L, que foram mantidos a 35&#730;C por 72 horas na suspensão de Enterococcus faecalis em SBF (0.085 UA; 660nm). Alíquotas de 100&#956;L foram tomadas da suspensão a cada 24 horas, realizadas as diluições seriadas e semeadas em triplicata em placa de Petri contendo meio Nutriente acrescido de azul de bromotimol a 0,001%. As placas foram incubadas a 35&#730;C por 48 horas e então realizadas as contagens de UFC. Ao final de 72 horas, corpos de prova em resina (n=10), que haviam sido mantidos na mesma suspensão juntamente com os demais grupos, tiveram a suspensão renovada, tendo sido ajustada para 0.1 UA (660nm). Permaneceram por mais 72 horas em estufa a 35&#730;C e então foram submetidos ao teste de aderência. Resultados: Para a comparação intergrupos considerando a variação do número de UFC em dois períodos houve diferença significante entre o grupo P e demais grupos no intervalo (T0-24h) e no intervalo (48-72h) para o grupo C comparado ao grupo L e P (Teste Anova teste t; &#945;=0.01). Conclusões: Os cimentos MTA cinza e branco, com ou sem nanopartículas, apresentaram ação antimicrobiana sobre Enterococcus faecalis em todos os períodos do teste de contato direto; A adição da nanopartícula de prata em pó promoveu um efeito antimicrobiano em menor tempo sobre o Enterococcus faecalis, no teste de contato direto; O MTA branco, com nanopartículas não permitiu a aderência bacteriana ao final de 72 horas em contato com a suspensão bacteriana de Enterococcus faecalis. / Aim: To evaluate if the addition of silver nanoparticles to white MTA cement will improve the antimicrobial action of Enterococcus faecalis and prevent adherence of this microorganism to the material. Method: Direct contact test using samples of materials: white MTA (n=10) B group, gray MTA (n=10) C group, white MTA + NPAG powder to 1wt% (n=10) P group, white MTA + solution NPAG of 50ppm (n=10) L group were kept at 35&#730;C for 72 hours in Enterococcus faecalis in SBF(0.085AU; 660nm). Aliquots of the suspension were taken every 24 hours, serial dilutions carried out in triplicate and plated on Petri dishes containing nutrient medium plus bromothymol blue 0.001%. The plates were incubated at 35&#730;C for 48 hours and then the CFU counts performed. At the end of 72 hours resin specimens (n=10) which had been kept at the same suspension together with the remaining groups all had renewed suspension having been adjusted to 0.1AU (660nm). Lasted for over 72 hours in an oven at 35&#730;C and then were tested for adhesion. Results: Comparing between those groups consider the variation of numbers of CFU in two periods there was significant differente between the P group and other groups in the interval (T0-24h) and range (48-72h) for group C compared with group L and P (Anova test - t test; &#945;=00:01). Conclusions: The gray and white MTA, with or without nanoparticles showed antimicrobial activity on Enterococcus faecalis at all periods of direct contact test; the silver nanoparticle powder addition promoted an antimicrobial effect in less time on the Enterococcus faecalis in test direct contact; white MTA with nanoparticles prevented bacterial adherence at the end of 72 hours in contact with the bacterial suspension of Enterococcus faecalis.

Denna studie syftar till att undersöka hur ultraljudsutbildningar för ingenjörer köps in, vad de innehåller, hur de genomförs, utvärderas och vilka resultatutbildningarna leder till. Totalt intervjuades sex sjukhus runt om i Sverige där elva medicintekniska ingenjörer och fyra verksamhetschefer deltog. En kvalitativ metod användes i studien i form av semistrukturerade intervjuer som grund för att analysera frågeställningarna. Resultatet visade att utbildningar köps in i upphandling av nya ultraljudsmaskiner och genomförs under garantiåren. Utbildningarna hålls av leverantörerna och de brukar vara i två dagar. Effekterna av utbildningarna varierar och beror på vilket serviceavtal som sjukhusen har. Det saknas en formell modell för utvärdering och uppföljning, trots det faktum att det i årliga möten diskuteras hur utbildningarna har gått och vilka kompetenser som behövs. Resultatet från studien kan främst användas i syfte att skapa bättre utbildningar, underlätta kommunikationen mellan sjukhus och leverantör om vad kursen innebär, samt vad ingenjörerna föredrar för innehåll i kurser för att kunna utvecklas inom ultraljud. / This study aims to investigate how ultrasound training for engineers is purchased, including how it is carried out and evaluated, what the different courses contain and what result the courses lead to. Six hospitals around Sweden were interviewed, where eleven medical engineers and four business managers participated. A qualitative method was used in the study with semi-structured interviews as a basis for analysing the issues. The results showed that the training courses are purchased in the procurement of new ultrasound machines and are carried out during the warranty years. The suppliers hold the training courses, which are usually held for two days. The effects of training vary and depend on the service agreement that the hospitals have. There is no formal model for evaluation and follow-up, even though annual meetings discuss how the training has gone and what skills are needed. The results can mainly be used to create better training and improve communication between hospital and supplier about what the course entails and what the engineers prefer for the content of courses to develop in the area.

Objetivo: comparar la resistencia compresiva del agregado trióxido mineral y Biodentine TM en perforaciones de furca de molares inferiores permanentes. Materiales y métodos: se seleccionaron 30 molares inferiores humanas. Se preparó un acceso cavitario endodóntico en cada uno de los dientes para luego decoronarlos y seccionarlos eliminando las raíces, se aplicó silicona por debajo de furca y se agregó acrílico alrededor de los especímenes, empleando un molde cilíndrico. Las muestras fueron divididas aleatoriamente en 3 grupos: Grupo 1: 10 especímenes en los que se creó una perforación de furca, sellada con MTA. Grupo 2: 10 especímenes en los que se creó una perforación de furca, sellada con Biodentine TM . Grupo control negativo: 10 especímenes sin perforación. Después de 30 días, los especímenes fueron sometidos a fuerzas compresivas empleando una máquina de ensayos universales registrando la fuerza necesaria para producir la fractura. Los datos fueron procesados con las pruebas estadísticas ANOVA y Tukey, con un nivel de significancia p<0.05. Resultados: La resistencia compresiva del Biodentine (190.84 MPa) no presentó diferencias estadísticamente significativas al ser comparada con MTA (165.29 MPa) en perforaciones de furca de molares inferiores permanentes, a los 30 días de evaluación. Sin embargo, la resistencia compresiva del MTA sí presentó diferencia estadística significativa al ser comparada con el grupo control (213.46 Mpa). TM Conclusión: El Biodentine presenta valores similares al ser comparado con el grupo control y MTA. Mientras que, MTA presenta diferencias con el control, además de los valores más bajos respecto a los demás grupos. TM / Objective: to compare the compressive strength of mineral trioxide aggregate and BiodentineTM in furca perforations of permanent lower molars. Materials and methods: 30 human lower molars were selected. An endodontic cavity access was prepared in each of the teeth and then decoronated and sectioned eliminating the roots, silicone was applied under the furcation and acrylic was added around the specimens, using a cylindrical mold. The specimens were randomly divided into 3 groups: Group 1: 10 specimens in which a furcation perforation was created, sealed with MTA. Group 2: 10 specimens in which a furcation perforation was created, sealed with Biodentine . Negative control group: 10 specimens without perforation. After 30 days, the specimens were subjected to compressive forces using a universal testing machine recording the force required to produce the fracture. The data were processed with ANOVA and Tukey statistical tests, with a significance level of p<0.05. TM Results: The compressive strength of Biodentine (190.84 MPa) did not present statistically significant differences when compared to MTA (165.29 MPa) in furcation perforations of lower permanent molars at 30 days of evaluation. However, the compressive strength of MTA did show a statistically significant difference when compared to the control group (213.46 MPa). TM Conclusion: Biodentine TM presented similar values when compared with the control group and MTA. While, MTA presents differences with the control, in addition to the lower values with respect to the other groups.

The purpose of this study was to quantitatively compare the fill density of MTA produced by hand condensation and hand condensation with indirect ultrasonic activation. Thirty acrylic block with 30 degree curved canals (group C) and 30 with straight canals (group S) were instrumented to a final apical size of 45 of 0.06 taper crown-down technique. After irrigating with water and drying with paper points, each block was weighed to the nearest 0.0001g with a digital electronic balance. In half of the specimens, chosen at random, the canal first filled with MTA using the hand condensation method (H) then weighed. The MTA was removed. The canal was rinsed, dried, and refilled using hand condensation with indirect ultrasonic activation (US). In the other half of the specimens, the procedure was carried out identically but in reverse order. The blocks were weighed again after cleaning the MTA from the canal as well as after refilling the canal using indirect ultrasonic condensation. Data comparing the weight of MTA between the two placement methods and the two canal configurations were analyzed by a two-way ANOVA. There was a statistically significant increase in weight of MTA produced by ultrasonic activation than by hand condensation in groups C (p<.0001) and S (p<.0001). However, there was no statistically significant difference when comparing the straight canal versus the 30-degree curved canal (p = .08). In group C, ultrasonic condensation resulted in a 10.07% increase in the weight of MTA over hand condensation alone. Similarly in group S, there was a 9.1% increase in the weight of MTA over hand condensation. In conclusion, hand condensation with indirect ultrasonic activation resulted in an MTA fill that was denser than that accomplished by hand condensation alone.

The use of Mineral Trioxide Aggregate (MTA) is gaining popularity among clinicians. Despite the many ideal qualities it possesses, it is often difficult to manipulate and often requires a second appointment for placement of a restoration to allow for setting. If the time to set of MTA can be accelerated to a single appointment time frame without significantly altering its properties, then MTA may gain even wider acceptance. The purpose of this study is to identify the percentage of a Portland Cement Accelerator (PCA), that when added to MTA, will decrease the time to set of MTA towards a single appointment time frame. Ten Teflon sample molds were prepared to hold 20 standardized chambers in each. Three sample molds were prepared with a 5.0% (by weight of MTA) accelerator, 3 with 10.0% accelerator and 3 with 15.0% accelerator mixed with MTA and water. Another sample mold contained a mixture of MTA and water only and acted as the control. Samples were tested using a dial indicator microgauge apparatus that measured the depth of needle penetration starting at 2 minutes and then every minute up to 15 minutes. Samples were also tested at 3, 4, 24, 48 and 72 hours. A mixed-model repeated measures ANOVA showed the four accelerator groups were significantly different and there was a significant time trend. The 5.0% accelerator group set significantly faster compared to the 15.0% and the control at 15 minutes or less (p<0.05). In conclusion, it appears that 5.0% PCA when added to MTA can accelerate the setting reaction.

The objective of this study was to compare the time to final set and compressive strength of the white mineral trioxide aggregate (MTA) formulation to the original grey MTA. To test compressive strength, each MTA formulation was placed into Teflon split molds for four hours at 37° Celsius (C) and 100% humidity. Compressive strength of both MTA formulations was measured at 24 hours (n=12) and 21 days (n=19) using an Instron Testing Machine. For determination of time to final set, each MTA formulation (n=6) was placed into a metal mold and maintained at 37° C and 100% humidity while setting. At five-minute time intervals, an indenter needle was lowered onto the surface of the MTA material and allowed to remain in place for five seconds before it was removed from the specimen surface. This process was repeated until the needle failed to make a complete circular indentation in the MTA specimen. Results of a two-way ANOVA indicate that white MTA had a significantly higher compressive strength (mean=32.7 MPa) than grey MTA (mean=25.2 MPa) at 24 hours and no statistically significant differences at 21 days (white mean=38.6 MPa and grey mean=38.0 MPa). Using one-way ANOVA, results indicate that grey MTA had a significantly longer time to final setting time (mean=296 min) compared to white MTA (mean=276 min). Based on this study, the results suggest that white MTA is an effective substitute for grey MTA.

O objetivo deste estudo foi comparar a eficácia clínica, radiográfica e microscópica do formocresol (FC) de Buckley diluído a 1/5, hidróxido de cálcio PA (HC) e Agregado Trióxido Mineral (MTA) como agentes capeadores pulpares em dentes decíduos humanos acometidos por cárie extensa. Quarenta e cinco molares decíduos inferiores de 23 crianças com idades entre 5 e 9 anos foram tratados pela técnica convencional de pulpotomia. Os dentes foram aleatoriamente divididos entre os grupos experimentais (HC e MTA) e o grupo controle (FC). Após a remoção da polpa coronária e hemostasia, o tecido pulpar remanescente foi coberto com pasta de MTA ou pó de HC nos grupos experimentais. No grupo controle, uma bolinha de algodão umedecida na solução de FC diluído foi colocada por 5 minutos sobre o remanescente pulpar e então a câmara pulpar preenchida com óxido de zinco e eugenol. Todos os dentes foram restaurados com uma base de óxido de zinco e eugenol reforçado (IRM) e cimento de ionômero de vidro modificado por resina. As avaliações clínicas e radiográficas foram realizadas nos períodos de 3, 6, 12, 18, 24 e 30 meses do pós-operatório. Durante as avaliações, os dentes que se apresentavam no período normal de esfoliação, bem como, dentes considerados fracasso ao tratamento foram extraídos e processados para análise microscópica. Os cortes foram feitos seriadamente, no sentido vestíbulo-lingual e corados pela hematoxilina e eosina. A análise microscópica foi realizada de forma descritiva dos fenômenos mais marcantes ocorridos no tecido pulpar remanescente. Pelos resultados clínicos e radiográficos obtidos foi possível observar uma taxa de sucesso para os grupos FC, HC e MTA de 100%, 35,7% e 100%, respectivamente. Diferença estatisticamente significativa foi observada quanto à presença de reabsorção interna, lesão inter- radicular, mobilidade e fístula para o grupo HC (p < 0,05). A análise microscópica para o grupo FC revelou presença de intenso infiltrado inflamatório e deposição de tecido mineralizado, irregular por todo canal radicular. Para o grupo MTA, notou-se deposição de material mineralizado de aspecto dentinóide, obliterando todo o canal radicular, além de áreas centrais preenchidas por tecido conjuntivo frouxo com inúmeros vasos sanguíneos. O grupo HC apresentou, na maioria dos cortes, extensa área de necrose tanto na câmara pulpar quanto no canal radicular. Em outros poucos cortes, presença de barreira de dentina reacional, obliterando a abertura coronária do canal radicular, com discreto infiltrado inflamatório crônico. O MTA parece ser um possível substituto do FC, no entanto, o hidróxido de cálcio mostrou ser uma técnica muito sensível e, portanto, não indicada para pulpotomias de dentes decíduos. / The aim of this study was to compare the clinical, radiographic and microscopic effectiveness of formocresol (FC), calcium hydroxide (CH) and trioxide mineral aggregate (MTA) as pulp dressing agents in carious primary teeth. Forty-five primary mandibular molars of 23 children between 5 and 9 years old were treated by conventional pulpotomy technique. The teeth were randomly assigned to the experimental (CH and MTA) or control (FC) groups. After coronal pulp removal and hemostasis, remaining pulp tissue was covered with a MTA paste or CH powder in the experimental groups. In the control group, diluted FC was placed over the pulp tissue with a cotton pellet for 5 minutes and removed; the pulp tissue was covered then with zinc oxide-eugenol (ZOE) paste. All the teeth were restored with reinforced zinc oxide-eugenol base and resin modified glass ionomer cement. Clinical and radiographic evaluations were recorded at 3, 6, 12, 18, 24 and 30-month follow-up. During the assessments, the teeth in the regular exfoliation period, as well as those considered as treatment failures were extracted and further processed for microscopic analysis. Serial sections were performed in the bucco-lingual direction and stained with hematoxylin and eosin. Microscopic analysis was performed as a description of the most remarkable phenomena in the remaining pulp tissue. Through clinical and radiographic results, success rates of 100%, 35.7% and 100% for FC, CH and MTA were found, respectively. Statistically significant differences were observed regarding to the presence of internal resorption, inter-radicular bone destruction, mobility and fistula for CH group (p < 0.05). Microscopic analysis revealed the presence of intense inflammatory infiltrate and mineralized tissue deposition, which was irregular throughout the root canal, in the FC group. As far as MTA group, dentin-like mineralized material deposition obliterating the root canal, and central areas filled by loose conjunctive tissue with several blood vessels were noticed. CH group presented, in most of the sections, extensive necrotic areas both in pulp chamber and root canal. Other sections revealed the presence of extensive reactive dentin barrier, which obliterated the coronal opening of the root canal, and a discrete chronic inflammatory infiltrate. MTA may serve as an effective substitute of FC in primary molar pulpotomies. However, CH seems to be a technique sensitive-material and therefore not indicated for pulpotomies of primary teeth.