A lesão periapical é uma doença causada por micro-organismos presentes no sistema de canais radiculares, assim como por seus produtos e subprodutos e pelas reações desencadeadas no organismo. A base para a obtenção do sucesso pós-tratamento endodôntico é o controle da infecção. Com essa finalidade, novos sistemas de irrigação dos canais radiculares têm sido desenvolvidos, no qual a irrigação por Pressão Apical Negativa (EndoVac®) tem se destacado. O objetivo desse estudo in vivo foi efetuar uma avaliação histopatológica, histoenzimológica e histomicrobiológica, comparando o sistema EndoVac® com a irrigação convencional, em dentes de cães com rizogênese incompleta e lesão periapical crônica induzida experimentalmente. Um total de 52 canais radiculares de pré-molares com rizogênese incompleta foram aleatoriamente divididos em 4 grupos: Grupo I - Irrigação com EndoVac® (n=15); Grupo II - Irrigação Convencional (n=17); Grupo III - Dente hígido (controle negativo) (n=10) e Grupo IV - Dente com lesão e sem tratamento (controle positivo) (n=10). Após indução de lesões periapicais nos dentes dos Grupos I, II e IV, os dentes dos grupos I e II foram instrumentados com limas manuais, empregando o EndoVac® e a irrigação convencional, respectivamente. Decorridos 90 dias, os animais foram eutanasiados e os espécimes submetidos ao processamento histotécnico para a análise histopatológica morfológica e morfométrica em cortes corados com HE, sob microscopia convencional e de fluorescência. Foi realizada também a histoenzimologia para a Fosfatase Ácida Resistente ao Tartarato (TRAP), para a marcação de osteoclastos, e a coloração de Brown e Brenn, para avaliar a presença de bactérias, sua localização e concentração/intensidade. Os resultados obtidos foram submetidos à análise estatística por meio dos testes de qui-quadrado, Fisher, Anova e pós-teste de Tukey. O nível de significância adotado foi de 5%. Os resultados obtidos na avaliação dos parâmetros histopatológicos evidenciaram diferença significante entre os Grupos I e II (p<0,05), observando-se no Grupo I predomínio de infiltrado inflamatório de menor magnitude, menor espessura do ligamento periodontal e menor reabsorção dos tecidos mineralizados. Embora não tenha sido verificada diferença significante entre esses grupos com relação à extensão das lesões periapicais em microscopia de fluorescência, e com relação à presença, localização e intensidade da contaminação bacteriana, foi observado menor número de osteoclastos no Grupo I (p<0,05). Os resultados do presente estudo in vivo permitiram concluir que a irrigação por pressão apical negativa (EndoVac®) apresentou melhores resultados biológicos, quando comparada à irrigação convencional, favorecendo a ocorrência do processo de reparo, em dentes com rizogênese incompleta e lesão periapical. / The apical periodontitis is a disease caused by microorganisms from the root canal system, as well as their products, by-products and the reactions triggered in the host. The postendodontic treatment success is based in the control of the infection. For this purpose, new irrigation systems of root canals have been developed, in which apical Negative Pressure (EndoVac®) have been highlighted. The objective of this in vivo study was to perform a histopathological, histoenzymology and histomicrobiologic evaluation, comparing the EndoVac® system with the conventional irrigation, in immature teeth of dogs with apical periodontitis experimentally induced. A total of 52 root canals of immature pre-molars were randomly assigned into 4 groups: Group I - EndoVac® Irrigation (n= 15); Group II - Conventional Irrigation (n= 17); Group III - Sound Tooth (negative control) (n= 10) and Group IV - Tooth with apical periodontitis without treatment (positive control) (n= 10). After induction of apical periodontitis in teeth of the Groups I, II and IV, in the groups I and II, the teeth were instrumented with manuals files, using EndoVac® and conventional irrigation, respectively. After 90 days, the animals were euthanized and the specimens subjected to histotechnic for histopathological, morphologic and morphometric analysis in HE-stained sections, under conventional and fluorescence microscopy. The histoenzymology for the phosphatase-Resistant Acid tartrate (TRAP), for the identification of osteoclasts, and the Brown and Brenn staining method to assess the presence of bacteria, their location and concentration/intensity were also performed. The results obtained were subjected to statistical analysis using the chi-square test, Fisher exact test, ANOVA and Tukey post-test. The level of significance was set at 5%. The results obtained in the evaluation of histopathological parameters demonstrated a significant difference between groups I and II (p< 0.05). In the Group I, the predominance was inflammatory infiltrate of low magnitude, small thickness of the periodontal ligament and less resorption of mineralized tissues. Although the periapical lesions extension in fluorescence microscopy, and the presence, location, and intensity of bacterial contamination was not significant different between these groups, a lower number of osteoclasts in Group I (p< 0.05) was observed. The results of this in vivo study allowed us to conclude that the irrigation with EndoVac® presents best biological results in relation to conventional irrigation, favored the occurrence of the repair process, in immature teeth with apical periodontitis.

Objetivou-se avaliar se o curativo de hidróxido de cálcio realmente apresenta influência no selamento de obturações de canais, realizadas com cimento de óxido de zinco e eugenol, utilizando-se o transporte de fluídos e a infiltração de corantes com azul de metileno e rodamina B. Foram utilizadas 70 raízes que tiveram seus canais obturados pela técnica da condensação lateral com cimento de óxido de zinco e eugenol, após o uso ou não do curativo de hidróxido de cálcio. A infiltração marginal apical foi avaliada utilizando-se, primeiramente, o sistema de transporte de fluído e, posteriormente, os mesmos espécimes foram imersos em corante, sendo uma metade em Rodamina B a 0,2% e a outra em azul de metileno a 0,5%. Os resultados obtidos mostraram que tanto com o sistema de transporte de fluído, como com a utilização da Rodamina B, o curativo de hidróxido de cálcio não teve qualquer influência no selamento apical das obturações. Todavia, os resultados foram significantes quando da marcação pelo azul de metileno, demonstrando haver interferência desse curativo, a qual tem sido relatada como que física e que, provavelmente, melhoraria a capacidade de selamento das obturações. A observação desse resultado isoladamente poderia levar a supor da possibilidade dessa ocorrência. Contudo, considerando-se que apenas os resultados utilizando o azul de metileno mostraram diferença estatisticamente significante entre os grupos com e sem uso de curativo, o mais sensato é concluir que o hidróxido de cálcio, muito provavelmente, tenha apresentado interação química com o azul de metileno, o que deve ter promovido sua descoloração (pela ação da alcalinidade do hidróxido de cálcio) e resultando, portanto, em dados não confiáveis. / Filling of the root canal system is the end of a sequence of cleaning, shaping and removing bacteria from root canals, and should seal them as more hermetic as possible. Many filling techniques and materials are continuously being developed, trying to reach a perfect seal of the root canal system. The necessity of testing such techniques and material produces a lot of papers analyzing biological and physical properties of root canal fillings. Apical sealing is the more tested physical property, although there is not standardization for it that could provide unquestionable results. Seventy roots canals were filled by the lateral condensation technique with zinc-oxide eugenol sealer, after the use or not of a intracanal medicament of calcium hydroxide paste. Apical marginal leakage was assessed firstly by a fluid transport system and, then, the roots were divided in two groups, being immersed in Rhodamine B or methylene blue dye solutions. Either the fluid transport system results as the Rhodamine B ones, showed no statistically influence of calcium hydroxide use in the sealing capacity of the root fillings. However, when methylene blue was used as tracer, the results were significant, indicating a direct influence of this root canal dressing in the quality of apical sealing of the fillings. This fact is usually explained as a physical action of calcium hydroxide, what should improve the apical sealing. If this finding would be analyzed solely, we could suppose and believe in it but, considering that only methylene blue test showed this statistically significant finding between dressing and no dressing groups, it\'s reasonable to conclude that a chemical interaction between calcium hydroxide and methylene blue should happen, making this tracer uncolored (through alkalinity action), giving us no trustable results at all.

Objetivou-se avaliar se o curativo de hidróxido de cálcio realmente apresenta influência no selamento de obturações de canais, realizadas com cimento de óxido de zinco e eugenol, utilizando-se o transporte de fluídos e a infiltração de corantes com azul de metileno e rodamina B. Foram utilizadas 70 raízes que tiveram seus canais obturados pela técnica da condensação lateral com cimento de óxido de zinco e eugenol, após o uso ou não do curativo de hidróxido de cálcio. A infiltração marginal apical foi avaliada utilizando-se, primeiramente, o sistema de transporte de fluído e, posteriormente, os mesmos espécimes foram imersos em corante, sendo uma metade em Rodamina B a 0,2% e a outra em azul de metileno a 0,5%. Os resultados obtidos mostraram que tanto com o sistema de transporte de fluído, como com a utilização da Rodamina B, o curativo de hidróxido de cálcio não teve qualquer influência no selamento apical das obturações. Todavia, os resultados foram significantes quando da marcação pelo azul de metileno, demonstrando haver interferência desse curativo, a qual tem sido relatada como que física e que, provavelmente, melhoraria a capacidade de selamento das obturações. A observação desse resultado isoladamente poderia levar a supor da possibilidade dessa ocorrência. Contudo, considerando-se que apenas os resultados utilizando o azul de metileno mostraram diferença estatisticamente significante entre os grupos com e sem uso de curativo, o mais sensato é concluir que o hidróxido de cálcio, muito provavelmente, tenha apresentado interação química com o azul de metileno, o que deve ter promovido sua descoloração (pela ação da alcalinidade do hidróxido de cálcio) e resultando, portanto, em dados não confiáveis. / Filling of the root canal system is the end of a sequence of cleaning, shaping and removing bacteria from root canals, and should seal them as more hermetic as possible. Many filling techniques and materials are continuously being developed, trying to reach a perfect seal of the root canal system. The necessity of testing such techniques and material produces a lot of papers analyzing biological and physical properties of root canal fillings. Apical sealing is the more tested physical property, although there is not standardization for it that could provide unquestionable results. Seventy roots canals were filled by the lateral condensation technique with zinc-oxide eugenol sealer, after the use or not of a intracanal medicament of calcium hydroxide paste. Apical marginal leakage was assessed firstly by a fluid transport system and, then, the roots were divided in two groups, being immersed in Rhodamine B or methylene blue dye solutions. Either the fluid transport system results as the Rhodamine B ones, showed no statistically influence of calcium hydroxide use in the sealing capacity of the root fillings. However, when methylene blue was used as tracer, the results were significant, indicating a direct influence of this root canal dressing in the quality of apical sealing of the fillings. This fact is usually explained as a physical action of calcium hydroxide, what should improve the apical sealing. If this finding would be analyzed solely, we could suppose and believe in it but, considering that only methylene blue test showed this statistically significant finding between dressing and no dressing groups, it\'s reasonable to conclude that a chemical interaction between calcium hydroxide and methylene blue should happen, making this tracer uncolored (through alkalinity action), giving us no trustable results at all.

Light is one of the environmental signals that regulate axillary shoot development. However, little is known about molecular and physiological mechanisms regulating the development of the axillary shoot in response to light signals. Molecular events associated with the enhanced apical dominance of phytochrome B mutant sorghum (Sorghum bicolor) were analyzed to reveal processes mediating axillary shoot development in response to light. The enhanced apical dominance of phyB-1 mutant sorghum is due to inhibition of bud outgrowth and is accompanied by upregulation of the dormancy-associated gene (SbDRM1) in the buds. Increased expression of the Teosinte Branched1 (SbTB1) gene (encoding a putative transcription factor that represses bud outgrowth) suggests that the inhibition of bud outgrowth in phyB-1 sorghum is due to the absence of active phyB to repress SbTB1. The results were confirmed by growing wild type seedlings at high plant density or with supplemental farred (FR) light that induces enhanced apical dominance. However, the SbTB1 gene is not involved in the inhibition of bud outgrowth induced by defoliation in wild type seedlings. The results indicate variations in molecular mechanisms among different signals inhibiting branching. Increased expression of SbMAX2 (which encodes an F-box protein that represses bud outgrowth) in buds repressed by light and defoliation suggests common mechanisms at the downstream end of pathways inhibiting branching. The expression levels of several cell cycle-related genes including SbPCNA, SbHis4, SbCycD2, SbCycB and SbCDKB were down-regulated in the repressed buds of FRtreated and defoliated seedlings indicating the suspension of cell division in those buds. However, these cell cycle-related genes were continuously expressed in the repressed buds of phyB-1, suggesting that inhibition of bud outgrowth in phyB-1 is not associated with down-regulation of cell cycle-related gene expression. The down-regulation of cell cycle-related genes in the buds of FR-treated wild type seedlings indicates that other sensors, in addition to phyB, regulate bud outgrowth in response to FR enrichment. The approaches used and results achieved will provide direction for future research on this important topic.

Thesis (Ph. D.)--University of Oregon, 1999. / Typescript. Includes vita and abstract. Includes bibliographical references (leaves 87-98). Also available for download via the World Wide Web; free to University of Oregon users. Address: http://wwwlib.umi.com/cr/uoregon/fullcit?p9947979.

Its known that the age-related decline in cognitive facilities is not due to the loss of neurons but more subtle changes in specific areas of the brain. Structural and morphological changes in cellular alignment in the minicolumns correlate with increased prevalence of neurological diseases and in aging. In the rhesus monkey, cognitive decline is similar to what humans experience in aging. In the monkey prefrontal cortex, Brodmann area 46, an important region for executive functioning, cognitive decline correlates with changes in cellular alignment or “columnar strength” as studies by Cruz et al., (2009). Using the density maps method in Area 46, the ventral bank was identified to be the most susceptible to structural changes. Minicolumns, are defined by the cellular alignment of neurons in the cortex and some believe that the dendritic bundles of neurons in the cortex is also considered an integral part of the columns. The functional role of apical dendrites, is not well understood, however, given the that repeated organized bundles transverse through the laminae could be further support for their inclusion in minicolumns with possible functional importance. If structural changes such as loss of columnar strength (neuronal displacement) that correlates with cognitive aging, it is possible that the dendritic organization may also be affected in this area. In this thesis, it is hypothesized that the dendritic bundles in this area could also be related to the cognitive deficits associated with normal aging. Using double- fluorescence labeling for dendrites (MAP-2) and neurons (Neu-N), 3D confocal reconstructions of the dorsal and ventral banks of Area 46 were used to investigate structural/morphological changes in the dendritic bundles in young and old rhesus monkeys. While cortical thickness and apical dendritic length between both banks did not change, we found a significant increase in inter-bundle spacing at layer 6A in the older monkeys in the ventral bank. Inter-bundle spacing for bundles in layer 5 was measured and showed that the young consistently have smaller inter-bundle spacing. Future studies with larger sample size will also investigate whether changes in dendritic bundles and their organization also correlate with age-related cognitive deficits.

A lesão periapical é uma doença causada por micro-organismos presentes no sistema de canais radiculares, assim como por seus produtos e subprodutos e pelas reações desencadeadas no organismo. A base para a obtenção do sucesso pós-tratamento endodôntico é o controle da infecção. Com essa finalidade, novos sistemas de irrigação dos canais radiculares têm sido desenvolvidos, no qual a irrigação por Pressão Apical Negativa (EndoVac®) tem se destacado. O objetivo desse estudo in vivo foi efetuar uma avaliação histopatológica, histoenzimológica e histomicrobiológica, comparando o sistema EndoVac® com a irrigação convencional, em dentes de cães com rizogênese incompleta e lesão periapical crônica induzida experimentalmente. Um total de 52 canais radiculares de pré-molares com rizogênese incompleta foram aleatoriamente divididos em 4 grupos: Grupo I - Irrigação com EndoVac® (n=15); Grupo II - Irrigação Convencional (n=17); Grupo III - Dente hígido (controle negativo) (n=10) e Grupo IV - Dente com lesão e sem tratamento (controle positivo) (n=10). Após indução de lesões periapicais nos dentes dos Grupos I, II e IV, os dentes dos grupos I e II foram instrumentados com limas manuais, empregando o EndoVac® e a irrigação convencional, respectivamente. Decorridos 90 dias, os animais foram eutanasiados e os espécimes submetidos ao processamento histotécnico para a análise histopatológica morfológica e morfométrica em cortes corados com HE, sob microscopia convencional e de fluorescência. Foi realizada também a histoenzimologia para a Fosfatase Ácida Resistente ao Tartarato (TRAP), para a marcação de osteoclastos, e a coloração de Brown e Brenn, para avaliar a presença de bactérias, sua localização e concentração/intensidade. Os resultados obtidos foram submetidos à análise estatística por meio dos testes de qui-quadrado, Fisher, Anova e pós-teste de Tukey. O nível de significância adotado foi de 5%. Os resultados obtidos na avaliação dos parâmetros histopatológicos evidenciaram diferença significante entre os Grupos I e II (p<0,05), observando-se no Grupo I predomínio de infiltrado inflamatório de menor magnitude, menor espessura do ligamento periodontal e menor reabsorção dos tecidos mineralizados. Embora não tenha sido verificada diferença significante entre esses grupos com relação à extensão das lesões periapicais em microscopia de fluorescência, e com relação à presença, localização e intensidade da contaminação bacteriana, foi observado menor número de osteoclastos no Grupo I (p<0,05). Os resultados do presente estudo in vivo permitiram concluir que a irrigação por pressão apical negativa (EndoVac®) apresentou melhores resultados biológicos, quando comparada à irrigação convencional, favorecendo a ocorrência do processo de reparo, em dentes com rizogênese incompleta e lesão periapical. / The apical periodontitis is a disease caused by microorganisms from the root canal system, as well as their products, by-products and the reactions triggered in the host. The postendodontic treatment success is based in the control of the infection. For this purpose, new irrigation systems of root canals have been developed, in which apical Negative Pressure (EndoVac®) have been highlighted. The objective of this in vivo study was to perform a histopathological, histoenzymology and histomicrobiologic evaluation, comparing the EndoVac® system with the conventional irrigation, in immature teeth of dogs with apical periodontitis experimentally induced. A total of 52 root canals of immature pre-molars were randomly assigned into 4 groups: Group I - EndoVac® Irrigation (n= 15); Group II - Conventional Irrigation (n= 17); Group III - Sound Tooth (negative control) (n= 10) and Group IV - Tooth with apical periodontitis without treatment (positive control) (n= 10). After induction of apical periodontitis in teeth of the Groups I, II and IV, in the groups I and II, the teeth were instrumented with manuals files, using EndoVac® and conventional irrigation, respectively. After 90 days, the animals were euthanized and the specimens subjected to histotechnic for histopathological, morphologic and morphometric analysis in HE-stained sections, under conventional and fluorescence microscopy. The histoenzymology for the phosphatase-Resistant Acid tartrate (TRAP), for the identification of osteoclasts, and the Brown and Brenn staining method to assess the presence of bacteria, their location and concentration/intensity were also performed. The results obtained were subjected to statistical analysis using the chi-square test, Fisher exact test, ANOVA and Tukey post-test. The level of significance was set at 5%. The results obtained in the evaluation of histopathological parameters demonstrated a significant difference between groups I and II (p< 0.05). In the Group I, the predominance was inflammatory infiltrate of low magnitude, small thickness of the periodontal ligament and less resorption of mineralized tissues. Although the periapical lesions extension in fluorescence microscopy, and the presence, location, and intensity of bacterial contamination was not significant different between these groups, a lower number of osteoclasts in Group I (p< 0.05) was observed. The results of this in vivo study allowed us to conclude that the irrigation with EndoVac® presents best biological results in relation to conventional irrigation, favored the occurrence of the repair process, in immature teeth with apical periodontitis.

No / The EyeSys videokeratoscope (VK) measurements of the principal corneal meridians of 98 subjects already analysed by Douthwaite et al. [Ophthal. Physiol. Opt. (1999)19:467¿474] were re-analysed in order to revise the assessment of asphericity, to derive information on corneal tilt and to assess the degree to which the corneal section approximates to that of a conic section. The range of normality for the revised p-value (asphericity) was from 0.57 to 0.97 for the near horizontal and from 0.56 to 1.08 in the near vertical principal meridians. The approximate corneal tilt angles ranged from ¿3.95 to +8.13 degrees in the horizontal and from ¿8.99 to +9.33 degrees in the vertical meridian. A tilted conicoidal surface will display a linear relationship (r = 1) when a scatterplot is drawn of the perpendicular distance squared vs radius squared, after first averaging the two semimeridian results for each VK ring. Analysing the results from the human cornea in the same way allows an assessment of the degree to which the corneal section approximates to that of the conic section.

Symptomatic apical periodontitis (SAP) is indicative of inflammation of the periodontal ligament. It may or may not be accompanied by radiographic changes and may occur with vital or necrotic pulpal diagnosis. Purpose of this study was to analyze clinical and radiographic presentations of SAP in a retrospective electronic dental chart and digital radiograph review utilizing the endodontic diagnostic template note of predoctoral dental school patients presenting with SAP. The aim was to determine prevalence of periapical radiolucencies (PARLs) in SAP, association of SAP to pulpal diagnosis, and define associated radiographic changes. Most prevalent pulpal diagnosis with SAP was symptomatic irreversible pulpitis (44%). A tooth presenting with SAP was more likely to have an intact lamina dura, but presented with a PARL 38% of the time. When a PARL was present the most common pulpal diagnosis was pulp necrosis however, 24.5% of teeth presented with a vital pulp diagnosis and lesions <2mm.

O chá verde vem sendo utilizado na prevenção e tratamento de variadas doenças infecciosas e imunoinflamatórias, por apresentar efeitos benéficos decorrentes da presença de Epigalocatequina-3-galato (EGCG). Esta catequina apresenta papel antiinflamatório, anti-oxidante, anti-microbiano e mineralizador e poderia ser utilizado no tratamento da doença periapical. O objetivo do presente trabalho foi avaliar o efeito uma pasta à base de EGCG utilizada como curativo de demora em lesões periapicais experimentalmente induzidas em cães. Um total de 80 raízes de pré-molares de cão com rizogênese completa e lesões periapicais experimentalmente induzidas, foram aleatoriamente divididos em 4 grupos submetidos à diferentes protocolos de tratamento endodôntico: 1) curativo de demora com pasta à base de EGCG; 2) curativo de demora com EGCG em veículo aquoso; 3) curativo de demora com pasta à base hidróxido de cálcio (Pasta Calen); 4) tratamento endodôntico em sessão única. Para avaliação da resposta tecidual, os dentes foram avaliados radiograficamente e histopatologicamente. As imagens radiográficas obtidas antes e 120 dias após o tratamento, foram fotografadas e digitalizadas para o programa Image J 1.28 para mensuração das áreas (mm&sup2;) radiolúcidas periapicais. Aos 120 dias após a obturação doa canais radiculares os animais foram eutanasiados e os espécimes foram processados histotecnicamente, corados com HE e avaliados com microscopia de luz convencional e de fluorescência (infiltrado inflamatório, espessamento do ligamento periodontal e reabsorção de tecidos mineralizados). Os resultados obtidos foram analisados estatisticamente utilizando os testes quiquadrado, Fisher, Anova e pós teste de Tukey, com nível de significância de 5% em todos os testes. De acordo com os resultados radiográficos, o percentual médio de redução da área radiolúcida (± erro padrão da média) foi semelhante (p>0,05) nos grupos EGCG em veículo aquoso (64,57%; ±7,514); pasta à base de EGCG (59,95%; ±8,023) e pasta à base de hidróxido de cálcio (58,65%; ±6,192). Todos foram superiores ao grupo tratado em sessão única (19,49%; ±2,881) (p<0,01). A análise histopatológica mostrou que os grupos que receberam aplicação de curativo de demora com EGCG ou hidróxido de cálcio, apresentaram reaparação da lesão periapical com semelhança em todos os parâmetros avaliados. Por outro lado, o tratamento em sessão única resultou em manutenção da lesão periapical, com maior espessura do ligamento periodontal (p<0,001), persistência de infiltrado inflamatório moderado ou severo (p<0,01) e presença de reabsorção óssea e cementária (p<0,0001). Foi possível concluir que a pasta à base de EGCG proporcionou o reparo de lesões periapicais, constituindo possível medicação intracanal alternativa / Green tea has been used in the prevention and treatment of various infectious and immunoinflammatory diseases, since it has beneficial effects due to the presence of Epigallocatechin-3-gallate (EGCG). This catequin present anti-inflammatory, antimicrobial, antioxidant and mineralizing role that could be usefull in the treatment of periapical disease. The aim of the present study was to evaluate the effect of the intracanal dressing with an EGCG paste-based im periapical lesions experimentaly induced in dogs. A total of 80 dog premolar roots with complete rhizogenesis and experimentally induced periapical lesions were randomly divided into 4 groups submitted to different endodontic treatment protocols:1) intracanal dressing with EGCG based paste; 2) intracanal dressing with EGCG in aqueous vehicle; 3) intracanal dressing with based paste on calcium hydroxide (Calen paste); 4) single session endodontic treatment. To evaluate the tissue response, the teeth were evaluated radiographically and histopathologically. Radiographic images are selected before 120 days after treatment, were photographed and scanned for the program Image J 1.28 for the measurement of periapical radiolucent areas (mm2). To 120 days after the root canal filling animals were euthanasied and the specimens processed, stained in the rotin HE and evaluated under conventional and fluorescence microscopy (inflammatory infiltrate, periodontal ligament space and mineralized tissue resorption). The results were compared statistically using chisquare, Fisher, Anova and Tukey post-test, with a significance level of 5% in all tests. According to the radiographic results, the mean percentage reduction of the radiolucent area (standard pattern of the mean) was similar (p> 0.05) in the EGCG groups in aqueous vehicle (64.57%; ± 7.514); EGCG based paste (59.95%, ± 8.023) and calcium hydroxide based paste (58.65%, ± 6.192). All groups were higher for the group treated in single session (19.49%, ± 2.881) (p <0.01). The histopathological analysis showed that the groups that received the prescription of intracanal dressings with EGCG or calcium hydroxide, resulted in periapical lesion repair and were similar in all the evaluated parameters. However, treatment in single session did not repair the periapical lesion resulting in greatest measure of the periodontal ligament (p <0.001), persistence of moderate or severe inflammatory infiltrate (p <0.01) and presence of bone and cementum resorption (p <0.0001). It is possible to conclude that EGCG paste-based allows the periapical lesions repair, constituting possible alternative intracanal medication