Abstract: This clinical study compared the effectiveness of two rotary systems: HyFlex CM (Coltene-Whaledent, Altstetten, Switzerland) and ProTaper Next (Dentsply Sirona, Ballaigues, Switzerland) on the removal of cultivable bacteria and endotoxins from primarily infected root canals. This study was designed as a randomized single-blinded, 2-arm, clinical trial. Twenty-four primarily infected root canals were selected and randomly divided into 2 groups: HyFlex CM (n = 12); and ProTaper Next (n = 12). Samples were collected before and after the biomechanical preparation and inoculated in specific flasks. Irrigation was performed using 2.5% sodium hypochlorite. A kinetic turbidimetric lysate assay of limulus amoebocytes was used to quantify endotoxins. Microbiological culture technique was used to determine the count of bacterial colony forming units (CFU/mL). Data collected were statistically analyzed using SigmaPlot 12.0 for Windows. The Two-Way ANOVA statistical test was performed and the level of significance was 5%. In the samples before the biomechanical preparation, cultivable bacteria and endotoxins were evidenced in 100% of the cases. The culture analysis revealed that there was no statistically significant difference in the bacterial reduction between the two instrumentation systems. Endotoxins were present in 100% of the canals after instrumentation and there was no statistical difference between the two systems in endotoxin reduction. Thus, it was concluded that both instrumentation systems were effective in reducing root canal bacteria and endotoxins with primary endodontic infection and that there was no statistical difference between them. However, no system was able to eliminate 100% of the bacteria and their by-products.

Abstract: Based on aroeira's (Myracrodruon urundeuva) antimicrobial activity and a future trend to compose intracanal medication, the aim of this study was to assess in vivo inflamatory tissue response to the extracts by edemogenic and histological analysis containing inactivated facultative and anaerobic microorganisms. For edema quantification, eighteen animals were divided into three groups (n = 3, periods: 3 and 6 hours) and 0.2 mL of 1% Evans blue per 100 g of body weight was injected into the penile vein under general anesthesia. After 30 min the animals received a subcutaneous injection in the dorsal region of aqueous or ethanolic extract of aroeira or saline (control) containing inactivated bacteria. Samples were collected, immersed in formamide for 72h, and evaluated by spectrophotometry (630 m). For histological analysis, polyethylene tubes with the extracts were implanted in the dorsal of 30 male rats. Analysis of the fibrous capsule and inflammatory infiltrate were performed after 7 and 30 days. The aqueous extract group induced less edema in both postoperative periods compared to the other groups, but the differences were not significant (p > 0.05). Tissue repair was significantly better after 30 days than after 7 days (p < 0.01). The aqueous solution showed less inflammatory response than the ethanolic solution (p < 0.05), with tendency for better results than control after 7 days. After 30 days, the response to both extracts was similar to control. The aqueous and ethanolic aroeira extracts containing inactivated microorganisms showed a trend for better results than saline, even when associated with microorganisms, and facilitated the tissue repair process.

Resumo Psidium cattleianum (PC) tem apresentado atividade inibitória frente diversos microrganismos, entretanto esse efeito ainda não foi testado contra microrganismos de interesse endodôntico. O objetivo desse estudo foi avaliar a atividade antimicrobiana e a biocompatibilidade dos extratos aquoso (EAPC) e hidroetanólico (EHPC) das folhas de Psidium cattleianum. As concentrações inibitória mínima (CIM) e letal mínima (CLM) foram determinadas pelo método de microdiluição em caldo, com o objetivo de analisar o efeito antimicrobiano frente Enterococcus faecalis, Pseudomonas aeruginosa, Actinomyces israelii e Candida albicans em condições planctônicas. Os ensaios de biofilme foram realizados somente com os extratos em que se determinou a CLM frente os microrganismos em condições planctônicas. Respostas teciduais imediata e tardia frente aos extratos de Psidium cattleianum foram avaliadas por teste edemogênico e análise histológica de implantes subcutâneos em ratos Wistar. Os resultados mostraram que CIM e CLM variaram entre 0,25 e 4 mg/mL. As CLMs determinadas pelo EHPC inibiram 100% do crescimento de todas as cepas testadas, exceto Candida albicans. EAPC apresentou o mesmo efeito para E. faecalis e P. aeruginosa. Ambos os extratos de PC conseguiram eliminar o biofilme de E. faecalis, e somente o EHPC eliminou o biofilme de P. aeruginosa. Os controles positivos inibiram o crescimento de todos os microrganismos testados nos ensaios de CIM e CLM, mas nenhuma das concentrações de clorexidina testadas foi capaz de eliminar o biofilme de A. israelii. O EAPC provocou um discreto aumento de edema com o tempo, enquanto EHPC provocou um edema inicial severo, que diminuiu progressivamente. Ambos os extratos EAPC e EHPC foram biocompatíveis, entretanto, EHPC apresentou melhores resultados com baixos níveis de inflamação em 28 dias. Pode-se concluir que EHPC foi biocompatível e apresentou melhor efeito antimicrobiano frente importantes patógenos associados a infecções endodônticas persistentes.

Abstract Psidium cattleianum (PC) has been displaying inhibitory effect against a variety of microorganisms, but this effect has not yet been tested against endodontic pathogens. The aim of this study was to evaluate the antimicrobial activity and biocompatibility of the aqueous (PCAE) and hydroethanolic (PCHE) extracts from Psidium cattleianum (PC) leaves. Minimum inhibitory concentration (MIC) and minimum lethal concentration (MLC) were determined using the microdilution broth method in order to analyze the antimicrobial effect against Enterococcus faecalis, Pseudomonas aeruginosa, Actinomyces israelii and Candida albicans in planktonic conditions. Biofilm assays were conducted only with the extracts that were able to determine the MLC for microorganisms in planktonic conditions. Immediate and late tissue reactions against PC extracts were evaluated using edemogenic test and histological analysis of subcutaneous implants in Wistar rats. The results showed that the MIC and MLC values ranged between 0.25 and 4 mg/mL. The MLC obtained for PCHE inhibited 100% growth of all the tested strains, except for C. albicans. PCAE had the same effect for E. faecalis and P. aeruginosa. Both PC extracts were able to eliminate E. faecalis biofilms and only the PCHE eliminated P. aeruginosa biofilms. The positive controls inhibited the growth of all tested strains in MIC and MLC essays, but no CHX tested concentrations were able to eliminate A. israelii biofilm. PCAE caused a discrete increase in the edema over time, while PCHE caused a higher initial edema, which decreased progressively. Both PCAE and PCHE extracts were biocompatible, but PCHE showed better results with slight levels of inflammation at 28 days. In conclusion, PCHE was biocompatible and presented better antimicrobial effect against important pathogens associated with persistent endodontic infections

Abstract The aim of this study was to evaluate edemogenic activity and subcutaneous inflammatory reaction induced by Psidium cattleianum leaf extracts associated with Ca(OH)2. Thirty male Wistar rats, split equally into three groups [aqueous extract + Ca(OH)2; ethanolic extract + Ca(OH)2; and propylene glycol + Ca(OH)2], were assessed every 3 h or 6 h (five animals in each period). Under general anesthesia, 0.2 mL of 1% Evans blue per 100 g of body weight was injected into the penile vein and each combination to be evaluated was subcutaneously injected into the dorsal region 30 min thereafter. Edemogenic activity was analyzed by spectrophotometry (λ=630 nm). For inflammatory reaction analysis, 50 rats received four polyethylene tubes (three experimental groups) and an empty tube (control group). The assessments were made at 7, 15, 30, 60, and 90 days, followed by hematoxylin-eosin staining and by the assignment of scores for evaluation of tissue response intensity. Ethanolic extract + Ca(OH)2 yielded the largest edemogenic activity at 3 h. Intergroup differences at 6 h were not significant. The histological analysis showed progressive repair over time (p<0.05) and aqueous and ethanolic extracts produced similar responses to those of the control and Ca(OH)2 + propylene glycol groups. Psidium cattleianum leaf extracts used as Ca(OH)2 vehicles evoked similar tissue response when compared to Ca(OH)2 associated with propylene glycol.

Abstract Obturation of the root canal system aims to fill empty spaces, promoting hermetic sealing and preventing bacterial activity in periapical tissues. This should provide optimal conditions for repair, stimulating the process of biomineralization. An endodontic sealer should be biocompatible once it is in direct contact with periapical tissues. The aim of this study was to evaluate the rat subcutaneous tissue response to implanted polyethylene tubes filled with Smartpaste Bio, Acroseal, and Sealapex and investigate mineralization ability of these endodontic sealers. Forty Wistar rats were assigned to the three sealers groups and control group, (n = 10 animals/group) and received subcutaneous implants containing the test sealers, and the control group were implanted with empty tubes. After days 7, 15, 30, and 60, animals were euthanized and polyethylene tubes were removed with the surrounding tissues. Inflammatory infiltrate and thickness of the fibrous capsule were histologically evaluated. Mineralization was analyzed by Von Kossa staining and polarized light. Data were tabulated and analyzed via Kruskal-Wallis and Dunn’s test. All tested materials induced a moderate inflammatory reaction in the initial periods. Smartpaste Bio induced the mildest inflammatory reactions after day 15. No difference was observed among groups after days 30 or 60. Von Kossa-positive staining and birefringent structures observed under polarized light revealed a larger mineralization area in Sealapex-treated animals followed by Smartpaste Bio-treated animals. At the end of the experiment, all tested sealers were found to be biocompatible. All sealers induced biomineralization, except Acroseal, which induced a mild tissue reaction.

A cirurgia apical deve ser considerada como a última opção de tratamento, e realizada quando o tratamento endodôntico convencional não proporciona o resultado esperado. Em dentes submetidos à cirurgia apical, o tipo de material retro-obturador é um dos fatores que interferem no reparo dos tecidos periapicais. O material em íntimo contato com os tecidos periapicais desempenha um papel fundamental no processo de reparo. Vários materiais têm sido estudados e indicados para o uso em procedimentos de cirurgias apicais, entretanto o agregado de trióxido mineral (MTA) ainda é o mais frequentemente utilizado. A regeneração tecidual guiada (GTR) tem sido proposta como um auxiliar na cirurgia apical para melhorar a formação óssea. Aqui é relatado um caso clínico em que a cirurgia apical foi realizada em conjunto com a reconstrução radicular do incisivo lateral superior esquerdo com MTA. Após a cirurgia apical, foi preparada uma retro-cavidade na parede vestibular e o dente envolvido foi obturado com MTA. Um enxerto de osso bovino e uma membrana de colágeno cortical foram colocados no defeito ósseo. Após 5 anos, avaliações clínica e radiográfica mostram que o tratamento foi bem sucedido. Pode-se concluir que o MTA apresenta características favoráveis em condições adversas e que pode ser usado em conjunto com GTR em casos envolvendo reconstrução radicular.

Apical surgery should be considered as the last treatment option and employed when conventional endodontic treatment does not provide the expected result. In teeth undergoing apical surgery, the type of retrograde filling material is one of the factors interfering with the repair of periapical tissues. The material in intimate contact with the periapical tissues plays a fundamental role in the repair process. Several materials have been studied and indicated for use in apical surgery procedures, but the mineral trioxide aggregate (MTA) is still the most frequently used one. Guided tissue regeneration (GTR) techniques have been proposed as an adjunct to apical surgery to enhance bone healing. Here is reported a clinical case in which apical surgery was performed in conjunction with MTA-based root reconstruction of the maxillary right second incisor. After the apical surgery, a root-end cavity was prepared at the vestibular face of the involved tooth and filled with MTA. A bovine bone graft and a cortical collagen membrane were placed on the bone defect. After 5 years, clinical and radiographic assessments showed that the treatment was successful. It may be concluded that MTA presents favorable characteristics in adverse conditions and can be used in conjunction with GTR in cases involving root reconstruction.

Some manufacturers have recently added specific components to improve the ease of handling and insertion material properties of MTA in order to create MTA-based sealers. Objective The aim of this study was to evaluate the healing of periapical lesions in canine teeth after a single session of endodontic treatment with MTA Fillapex® compared with Sealapex® or Endo-CPM-Sealer®. Material and Methods Sixty-two root canals were performed on two 1-year-old male dogs. After coronal access and pulp extirpation, the canals were exposed to the oral cavity for 6 months in order to induce periapical lesions. The root canals were prepared, irrigated with a solution of 2.5% sodium hypochlorite and filled with gutta-percha and different sealers, according to the following groups: 1) Sealapex®; 2) Endo-CPM-Sealer®; and 3) MTA Fillapex®. Some teeth with periapical lesions were left untreated for use as positive controls. Healthy teeth were used as negative controls. After 6 months, the animals were sacrificed and serial sections from the roots were prepared for histomorphologic analysis and stained with hematoxylin and eosin and the Brown and Brenn technique. The lesions were scored according to pre-established histomorphologic parameters and the scores statistically analyzed using the Kruskal-Wallis test. Results All 3 materials produced similar patterns of healing (p>0.05); in particular, persistent inflammation and absence of complete periapical tissue healing were consistently noted. Conclusions Preparation of the infected root canals followed by filling with the materials studied was insufficient to provide complete healing of the periapical tissues.

INTRODUÇÃO: O tratamento endodôntico é de fundamental importância para abolir a infecção presente em dentes que apresentam necrose pulpar. OBJETIVO: O objetivo do presente estudo foi avaliar clínica e radiograficamente a eficácia dos tratamentos de canais radiculares de dentes com lesão periapical crônica, efetuados pelos graduandos em Odontologia, da Faculdade de Odontologia de Araçatuba - UNESP. MATERIAL E MÉTODO: Foram selecionados 100 pacientes que possuíam dentes com lesão periapical crônica para serem tratados. Após o preparo biomecânico, os canais radiculares receberam uma medicação intracanal de hidróxido de cálcio durante o período de 14 dias. Os canais radiculares foram obturados com cimento endodôntico à base de hidróxido de cálcio. Foi realizada a proservação por um período entre oito e 11 meses. RESULTADO: A análise dos resultados permitiu constatar a porcentagem de 78,46% dos casos com reparo total da lesão periapical e de 21,54% dos casos em que não houve evidências de reparo. CONCLUSÃO: Ocorreu reparo das lesões periapicais nos dentes tratados pelos graduandos da Faculdade de Odontologia de Araçatuba - UNESP.

INTRODUCTION: Root canal treatment plays a fundamental role in abolishing infections in teeth showing pulp necrosis. OBJECTIVE: We aimed to evaluate the clinical and radiographic efficacy of root canal treatment for teeth with chronic periapical lesions, which was performed by students of Undergraduate Dentistry, Faculty of Dentistry, Campus Araçatuba - UNESP. MATERIAL AND METHOD: We selected 100 patients who had teeth with chronic periapical lesions. After biomechanical preparation, the root canal receiving of calcium hydroxide intracanal dressing during the 14 days. The root canals were filled with a calcium hydroxide-based endodontic sealer. Follow-up examinations were performed for at least 8 months. RESULT: An analysis of the results showed total repair in 78.46% of the cases and no evidence of repair in 21.54% of the cases. CONCLUSION: Repair occurred in the teeth with chronic periapical lesions treated by students of Undergraduate Dentistry, Faculty of Dentistry, Campus Araçatuba - UNESP.

OBJECTIVES: This study evaluated subcutaneous tissue response to Aroeira (Myracrodruon urundeuva) extract employing edemogenic and histological analyses. MATERIAL AND METHODS: Test groups consisted of aqueous and ethanolic Aroeira extracts and saline (control). For edema quantification, 18 rats received an intravenous injection of Evan's Blue. After 30 min, the extracts and saline were injected on the dorsum of the rats, which were then sacrificed after 3 and 6 h. Readings were performed in a spectrophotometer. For subcutaneous implantation, 30 rats received a polyethylene tube containing the extracts on their dorsum and then they were killed after 7 and 28 days. The samples were processed for histological analysis and evaluated with a light microscope. The inflammatory infiltrate was quantified. RESULTS: There were no statistically significant differences between aqueous extract and saline groups in relation to edema quantification in the different periods (p>0.05). Ethanolic solution resulted in more edema independently of the experimental period (p<0.05). Histological analysis showed similar results on the 7-day period for the 3 groups. There was a notable reduction on inflammatory cell number for saline and aqueous extract groups at 28 days. CONCLUSION: The aqueous extract showed biocompatible properties similar to those of saline.

OBJECTIVES: The aim of this study was to evaluate the apical sealability of Fillapex®, endo-CPM-Sealer® and Sealapex®. Material and Methods: Ninety-four freshly extracted single-rooted teeth were selected and decoronated. All teeth were radiographed to confirm the existence of a single and straight root canal, which was prepared using Protaper Universal and 2.5% sodium hypochlorite. The teeth were randomly divided in groups of 10 specimens each according to the sealer, and the canals were filled using the single cone technique and one of the sealers. Four additional teeth were used as controls. The teeth were submitted to dye leakage with Rhodamine B for 24 h but using vacuum on the initial 15 min. Thereafter, they were cut longitudinally and the leakage was measured in a linear fashion from apex to crown. Data were analyzed by ANOVA and Tukey's tests at 5% significance level. Results: Fillapex® and Sealapex® showed significantly less dye leakage than endo-CPM-Sealer® (p<0.05). Conclusions: It was concluded that Fillapex® and Sealapex® were able to prevent apical dye leakage differently from endo-CPM-Sealer®.

OBJECTIVE: This study evaluated the response of periapical tissues to the endodontic sealer Endométhasone in root canal fillings short of or beyond the apical foramen. MATERIAL AND METHODS: Twenty root canals of premolars and incisors of 2 mongrel dogs were used. After coronal access and pulp extirpation, the canals were instrumented up to a size 55 K-file and the apical cemental barrier was penetrated with a size 15 K-file to obtain a main apical foramen, which was widened to a size 25 K-file. The canals were irrigated with saline at each change of file. The root canals were obturated either short of or beyond the apical foramen by the lateral condensation of gutta-percha and Endométhasone, originating 2 experimental groups: G1: Endométhasone/short of the apical foramen; G2: Endométhasone/beyond the apical foramen. The animals were killed by anesthetic overdose 90 days after endodontic treatment. The individual roots were obtained and serial histological sections were prepared for histomorphological analysis (H&E and Brown & Brenn techniques) under light microscopy. The following parameters were examined: closure of the apical foramen of the main root canal and apical opening of accessory canals, apical cementum resorption, intensity of the inflammatory infiltrate, presence of giant cells and thickness and organization of the apical periodontal ligament. Each parameter was scored 1 to 4, 1 being the best result and 4 the worst. Data were analyzed statistically by the Wilcoxon nonparametric tests (p=0.05). RESULTS: Comparing the 2 groups, the best result (p<0.05) was obtained with root canal filling with Endométhasone short of the apical foramen but a chronic inflammatory infiltrate was present in all specimens. CONCLUSIONS: Limiting the filling material to the root canal space apically is important to determine the best treatment outcome when Endométhasone is used as sealer.

O capeamento pulpar é um procedimento que consiste na adequada proteção do tecido pulpar exposto ao meio oral, objetivando a preservação de sua vitalidade e suas funções. O objetivo deste trabalho foi observar a resposta da polpa dental de cães ao capeamento com o agregado de trióxido mineral (MTA) ou hidróxido de cálcio P.A. Para tanto, 37 dentes foram divididos em dois grupos, de acordo com o material capeador utilizado. Dois cães foram anestesiados e após o isolamento absoluto do campo operatório, realizou-se exposição padronizada da polpa, proteção com os materiais capeadores testados e selamento das cavidades com cimento modificado de ionômero de vidro. Os dentes foram então restaurados com resina composta. Após sessenta dias, os animais foram sacrificados e as peças foram processadas para a análise microscópica dos dentes. Observou-se que o MTA apresentou maior índice de sucesso em relação ao hidróxido de cálcio, evidenciando menor ocorrência de infecção e necrose pulpar.

Pulp capping is a procedure that comprises adequate protection of the pulp tissue exposed to the oral environment, aiming at the preservation of its vitality and functions. This study evaluated the response of the dental pulps of dog teeth to capping with mineral trioxide aggregate (MTA) or calcium hydroxide P.A. For that purpose, 37 teeth were divided into two groups, according to the capping material employed. Two dogs were anesthetized and, after placement of a rubber dam, their pulps were exposed in a standardized manner and protected with the experimental capping materials. The cavities were then sealed with resin-modified glass ionomer cement and restored with composite resin. After sixty days, the animals were killed and the specimens were processed in order to be analyzed with optic microscopy. It was observed that MTA presented a higher success rate compared to calcium hydroxide, presenting a lower occurrence of infection and pulp necrosis.

O objetivo de encontrar um material ideal para obturar canais radiculares de dentes decíduos ainda não foi alcançado. Esse fato estimulou a realização de uma experimentação para analisar histologicamente a reação dos tecidos periapicais a 3 materiais obturadores de canal. Assim, oitenta canais radiculares de dentes decíduos anteriores de 6 cães, com 60 dias de idade, fora empregados neste estudo. Após o preparo biomecânico, os canais radiculares foram obturados com os seguintes materiais: pasta lentamente reabsorvível de Maisto, Sealer 26 com iodofórmio, pasta L&C (hidróxido de cálcio com óleo de oliva) e, como grupo controle, dentes cujos canais foram preparados biomecanicamente mas não obturados. Trinta dias após o tratamento os animais foram mortos e as peças processados para análise histológica. Os resultados permitiram ordenar estatisticamente os materiais do melhor para o pior da seguinte maneira: a- Pasta de Maisto, b- Sealer 26 com iodofórmio, c- grupo controle, d- Pasta L&C. Foi observado diferença significante (p=0,01) somente quando os resultados dos diferentes grupos foram comparados com o grupo da pasta L&C. Foi também observado que a pasta L&C não foi biologicamente compatível enquanto os outros materiais foram biocompatíveis, porém suas velocidades de reabsorção não foram a mesma observada com as raízes dos dentes decíduos.

The problem of finding an ideal material for filling root canals of deciduous teeth has not been solved yet. This fact led to the development of an experiment to histologically analyze the periapical tissue reaction to 3 root canal filling materials. Eighty root canals of dog deciduous anterior teeth from 6 animals, 60 days old, were used in this study. After biomechanical preparation, the root canals were filled with the following materials: slowly resorbable Maisto paste, Sealer 26 with iodoform, L&C paste (calcium hydroxide with olive oil) and as a control group, canals that were prepared but not filled. At thirty days after the treatment the animals were killed and the teeth prepared for histological analysis. The materials were ranked statistically from the best to the worst as follows: a - Maisto paste, b - Sealer 26 with iodoform, c - control group, d - L&C paste. There was significant difference (p = 0.01) only when the results of the other groups were compared with the L&C paste group. It was also observed that L&C paste was not biologically compatible and that the other materials were biocompatible but their resorption was not at the same rate as that of the deciduous teeth roots.

O presente estudo in vivo comparou os efeitos do agregado de trióxido mineral (MTA), IRM, Super EBA e OZE na consistência de massa de vidraceiro, usados como material para obturação retrógrada, no processo de reparo dos tecidos periapicais de dentes despulpados de cães submetidos à técnica de retrobturação convencional. Vinte e quatro pré-molares obtidos de três cães foram usados. Na primeira intervenção, os animais foram anestesiados, e a abertura coronária e a pulpectomia foram realizadas. Os canais radiculares foram mantidos abertos ao meio oral por 180 dias para induzir a formação de lesão periapical. Após a remoção cirúrgica das lesões com curetas, 2 mm apicais da raiz foram seccionados perpendicularmente ao longo eixo do dente e uma cavidade apical foi preparada com broca esférica em baixa-rotação. As cavidades ósseas foram irrigadas e secas, e as cavidades apicais obturadas com MTA, IRM, Super EBA e OZE na consistência de massa de vidraceiro. As cavidades ósseas foram passivamente preenchidas com sangue e os retalhos suturados. As aberturas coronárias foram limpas e seladas duplamente com OZE e amálgama. Após 180 dias, os animais foram sacrificados por super-dosagem de anestésico, a maxila e a mandíbula foram removidas e as peças processadas para análise histomorfológica. Os dados foram avaliados cegamente com base nos vários eventos histomorfológicos e os escores obtidos foram analisados estatisticamente usando o teste Kruskal Wallis. Nenhuma diferença estatisticamente significante foi observada entre MTA, Super EBA e IRM (p>0,005). Entretanto, o OZE teve influência negativa significantemente maior no reparo apical (p<0,005). Estes resultados indicam que MTA, Super EBA e IRM tiveram efeitos histopatológicos similares entre eles e melhor performance que o OZE utilizado na consistência de massa de vidraceiro. Além disso, somente o MTA estimulou a deposição de tecido duro em contato direto com o material retrobturador, mesmo quando inserido sob condições críticas.

This in vivo study compared the effect of mineral trioxide aggregate (MTA), IRM, Super EBA and ZOE in a puttylike consistency, used as retrofilling materials, in the healing process of periapical tissue of pulpless dogs' teeth submitted to a conventional retrofilling technique. Twenty-four premolars obtained from three dogs were used. At the first intervention, the animals were anesthetized, coronal access was obtained and pulpectomy was done. Root canals were kept open to the oral environment for 180 days to induce the formation of apical lesions. After surgical removal of the lesions with curettes, 2 mm of the apical root was cut out perpendicular to the long axis of the teeth, and root-end cavities were shaped with a low-speed round bur. The bone cavities were irrigated and dried, and the root-end cavities were filled with MTA, IRM, Super EBA and ZOE in a puttylike consistency. The bone cavities were passively filled with blood and flaps were sutured. The coronal access openings were cleaned and double-sealed with ZOE and amalgam. After 180 days, the animals were killed by anesthetic overdose, maxilla and mandible were removed and the pieces were processed for histomorphologic analysis. Data were evaluated blindly on the basis of several histopathologic events and the scores obtained were analyzed statistically using the Kruskal Wallis test. No significant differences were observed among MTA, Super EBA and IRM (p>0.05). However, ZOE had a significantly more negative influence on the apical healing (p<0.05). In conclusion, MTA, Super EBA and IRM had similar histopathologic effects among each other and better performance than ZOE used in a puttylike consistency. Furthermore, only MTA stimulated hard tissue deposition in direct contact with the retrofilling material, even when it was inserted under critical conditions.

Foi propósito deste trabalho observar o processo de reparo de dentes de cães após obturação dos canais com dois cimentos diferentes, fazendo ou não a patência apical. Após uma sobreinstrumentação, os canais receberam um curativo de uma solução de corticosteróide-antibiótico por 7 dias, com o objetivo de obter invaginação de tecido conjuntivo para dentro dos canais. Após esse período, esse tecido foi totalmente removido em metade dos casos (grupos com patência apical) e preservados no restante dos casos (grupos sem patência apical). Os canais foram obturados pela técnica da condensação lateral empregando um cimento a base de hidróxido de cálcio (Sealer Plus) ou um cimento de Grossman (Fill Canal). Os animais foram sacrificados por overdose anestésica 60 dias após o tratamento endodôntico e as peças anatômicas foram obtidas e preparadas para análise histológica. Os dados obtidos foram analisados com base em diversos parâmetros histomorfológicos. Os resultados foram melhores nos grupos sem patência apical (p=0,01) do que nos grupos com patência. Dentre os cimentos estudados, os melhores resultados foram observados com o cimento Sealer Plus (p=0,01). Em conclusão, tanto a patência apical (presença ou ausência) quanto o tipo de material obturador de canal influíram no processo de reparo apical de dentes de cães com polpas vitais após tratamento endodôntico. O emprego de um cimento a base de hidróxido de cálcio em dentes sem patência apical promoveu os melhores resultados, dentre as condições experimentais propostas.

The purpose of this study was to investigate the periapical healing process of dogs' teeth with or without apical patency and after root canal filling with two types of sealers. Forty roots of premolars and incisors were utilized. The root canals were overinstrumented and dressed with a corticosteroid-antibiotic solution for 7 days to obtain ingrowth of periapical connective tissue into the canals. After this period, the tissue was removed in half of the specimens (groups with patency) and preserved in the other half (groups without patency). Canals were filled by lateral condensation technique with gutta-percha points and either a calcium hydroxide-based sealer (Sealer Plus) or a Grossman's cement (Fill Canal). The animals were killed by anesthetic overdose 60 days after the endodontic treatment and anatomic pieces were obtained and prepared for histologic examination. Data were evaluated in a blind analysis on the basis of several histomorphologic parameters. The groups without patency had better results (p=0.01) than those in which the ingrown connective tissue was removed. Comparing the sealers, Sealer Plus had significantly better results (p=0.01) than Fill Canal. In conclusion, both the apical patency (presence or absence) and the type of root canal filling material influenced the periapical healing process in dogs' teeth with vital pulp after root canal treatment. The use of a calcium hydroxide-based sealer in teeth without apical patency yielded the best results among the experimental conditions proposed.