Low-concentrated nonvital bleaching effect on bond strength of composite resin restorations / Efeito de clareadores não-vitais pouco concentrados sobre a força de cisalhamento de restaurações de resina composta

Objective: To investigate if short-term dentin bleaching with low-concentrated substances affects the bond strength of immediate resin composite restorations. Material and Methods: The buccal surfaces of fifty molar crowns were ground for dentin exposure and randomly assigned into 5 groups (n=10), according to the following treatments: sodium perborate + water; sodium perborate + 6% hydrogen peroxide; 6% hydrogen peroxide; 35% hydrogen peroxide (positive control), or no bleaching agent (negative control). The specimens were immediately restored with resin composite. Seven days after treatments, the shear bond test was performed in a universal test machine at a crosshead speed of 0.5 mm/min. Data were analyzed using ANOVA and Tukey’s HSD test (α = 0.05). Results: The shear bond strength mean values for the negative control group were higher than all experimental and positive control groups (p < 0.000), whose differences were not statistically significant (p > 0.05). Conclusion: Short-term dentin bleaching with sodium perborate+water, 6% hydrogen peroxide, or sodium perborate mixed with 6% hydrogen peroxide reduced the shear bond strength of immediate resin composite restorations.

Objetivo: Investigar se o clareamento rápido da dentina com substâncias de baixa concentração afeta a resistência de união ao cisalhamento de restaurações imediatas de resina composta. Material e Métodos: As superfícies vestibulares de cinquenta molares foram desgastadas para exposição da dentina e então aleatoriamente alocadas em 5 grupos (n = 10), de acordo com as substâncias clareadoras: perborato de sódio + água; perborato de sódio + peróxido de hidrogênio a 6%; peróxido de hidrogênio a 6%; peróxido de hidrogênio a 35% (controle positivo); ou nenhum agente clareador (controle negativo). Os espécimes foram imediatamente restaurados com resina composta. Sete dias após os tratamentos, testes de resistência ao cisalhamento foram realizados em uma máquina de ensaios universal a uma velocidade de cruzeta de 0,5 mm/min. Os dados foram analisados com os testes ANOVA e Tukey HSD (α = 0,05). Resultados: Os valores de resistência ao cisalhamento do grupo controle negativo foram maiores do que os dos grupos experimentais e controle positivo (p < 0,001), cujas diferenças não foram estatisticamente significativa (p > 0,05). Conclusão: Clareamentos dentinários rápidos com perborato de sódio, peróxido de hidrogênio 6% ou perborato de sódio misturado com peróxido de hidrogênio 6% reduziram a força de resistência ao cisalhamento de restaurações imediatas de resina composta.

Analysis of the reaction of subcutaneous tissues in rats and the antimicrobial activity of calcium hydroxide paste used in association with different substances

The aim of this study was to evaluate the subcutaneous tissue response in rats and the antimicrobial activity of intracanal calcium hydroxide dressings mixed with different substances against E. faecalis. Fifty four rats were divided into three experimental groups according to the vehicle in the calcium hydroxide treatment: 0.4% chlorohexidine in propylene glycol (PG),Casearia sylvestris Sw in PG and calcium hydroxide+PG (control group). The pastes were placed into polyethylene tubes and implanted into the subcutaneous tissue. After 7, 14 and 30 days, the samples were processed and histologically evaluated (hematoxylin and eosin). The tissue surface in contact with the material was analyzed, and the quantitative analysis determined the volume density occupied by the inflammatory infiltrate (giant cells, polymorphonuclear cells and mononuclear cells), fibroblasts, collagen fibers and blood vessels. For the antimicrobial analysis, 20 dentin blocks infected with E. faecalis were treated with calcium hydroxide pastes in different vehicles; 0.4% chlorhexidine in PG, PG, extract fromCasearia sylvestris Sw in PG and a positive control (infection and without medication) for 7 days. The efficiency of the pastes was evaluated by the live/dead technique and confocal microscopy. The results showed that 0.4% chlorhexidine induced a higher inflammatory response than the other groups. The Casearia sylvestris Sw extract showed satisfactory results in relation to the intensity of the inflammatory response. In the microbiological test, there were no statistical differences between the evaluated intracanal dressings and the percentage of bacterial viability was between 33 and 42%. The control group showed an 86% viability. Antimicrobial components such as chlorhexidine or Casearia sylvestris Sw did not improve the antimicrobial activity against E. faecalis in comparison to the calcium hydroxide+PG treatment. In addition, the incorporation of chlorhexidine in the calcium hydroxide paste promoted the highest inflammatory response.

Reconstrução de dentes para o tratamento endodôntico / Teeth reconstruction for endodontic treatment

O isolamento do campo operatório com o dique de borracha é fundamental para o tratamento endodôntico, porém alguns dentes se apresentam com grande destruição coronária, dificultando ou mesmo impedindo sua colocação. A reconstrução da coroa dentária por meio de resina fotoativada é um procedimento fácil de ser realizado e que, além de reforçar a coroa do dente, propicia maior facilidade para fazer o isolamento do mesmo. Este artigo descreve a técnica para a reconstrução da coroa dental, para isolamento do campo operatório com dique de borracha.

The use of rubber dam is vital for endodontic treatment, however some teeth present themselves with large coronary destruction hindering or even preventing the placement of the rubber dam. The reconstruction of dental crown using light-activated resin is a procedure that in addition to strengthening the crown of the tooth facilitates posterior isolation of the tooth. This article describes a technique for reconstruction of dental crown with the purpose of facilitating the use of rubber dam.

Rat subcutaneous tissue response to calcium silicate containing different arsenic concentrations

Objective: To evaluate the response of rat subcutaneous tissue in implanted polyethylene tubes that were filled with GMTA Angelus and Portland cements containing different arsenic concentrations. Material and Methods: Atomic absorption spectrophotometry was utilized to obtain the values of the arsenic concentration in the materials. Thirty-six rats were divided into 3 groups of 12 animals for each experimental period. Each animal received two implants of polyethylene tubes filled with different test cements and the lateral of the tubes was used as a control group. After 15, 30 and 60 days of implantation, the animals were killed and the specimens were prepared for descriptive and morphometric analysis considering: inflammatory cells, collagen fibers, fibroblasts, blood vessels and other components. The results were analyzed utilizing the Kuskal-Wallis test and the Dunn's Multiple test for comparison (p<0.05). Results: The materials showed, according to atomic absorption spectrophotometry, the following doses of arsenic: GMTA Angelus: 5.01 mg/kg, WPC Irajazinho: 0.69 mg/kg, GPC Minetti: 18.46 mg/kg and GPC Votoran: 10.76 mg/kg. In a 60-day periods, all specimens displayed a neoformation of connective tissue with a structure of fibrocellular aspect (capsule). Control groups and MTA Angelus produced the lower amount of inflammatory reaction and GPC Minetti, the highest reaction. Conclusions: There was no direct relationship between the concentration of arsenic present in the composition of the materials and the intensity of the inflammatory reactions. Higher values, as 18.46 mg/kg of arsenic in the cement, produce characteristics of severe inflammation reaction at the 60-day period. The best results were found in MTA angelus. .

Influence of bismuth oxide concentration on the pH level and biocompatibility of white Portland cement

Objectives: To investigate if there is a relation between the increase of bismuth oxide and the decrease of pH levels and an intensification of toxicity in the Portland cement. Material and Methods: White Portland cement (WPC) was mixed with 0, 15, 20, 30 and 50% bismuth oxide, in weight. For the pH level test, polyethylene tubes were filled with the cements and immersed in Milli-Q water for 15, 30 and 60 days. After each period, the increase of the pH level was assessed. For the biocompatibility, two polyethylene tubes filled with the cements were implanted in ninety albino rats (n=6). The analysis of the intensity of the inflammatory infiltrate was performed after 15, 30 and 60 days. The statistical analysis was performed using the Kruskal-Wallis, Dunn and Friedman tests for the pH level and the Kruskal-Wallis and Dunn tests for the biological analysis (p<0.05). Results: The results showed an increase of the pH level after 15 days, followed by a slight increase after 30 days and a decrease after 60 days. There were no significant statistical differences among the groups (p>0.05). For the inflammatory infiltrates, no significant statistical differences were found among the groups in each period (p>0.05). The 15% WPC showed a significant decrease of the inflammatory infiltrate from 15 to 30 and 60 days (p<0.05). Conclusions: The addition of bismuth oxide into Portland cement did not affect the pH level and the biological response. The concentration of 15% of bismuth oxide resulted in significant reduction in inflammatory response in comparison with the other concentrations evaluated. .

Análise microscópica de incisões realizadas com três diferentes pontas do laser Erbio YAG / Microscopic evaluation of incision with three different Er-YAG laser tips

Analisou-se microscopicamente o processo de reparo de incisões realizadas na derme de ratos, utilizando três pontas diferentes do laser de Erbio YAG. Foram selecionados 6 ratos, nos quais, após depilação da região dorsal e anestesia, foram submetidos a incisões com o Laser Erbio-YAG, utilizando as peças de mão 2051, peça de mão 2055 com fibra óptica de forma cilíndrica e peça de mão 2056 com fibra óptica de forma de espátula. Os animais foram mortos após 7 e 14 dias, sendo que nesse momento, as feridas incisionais foram fotografadas. As peças contendo a região incisada foram preparadas para análise microscópica, realizando-se secções de 7µm e coloração com hematoxilina e eosina. Avaliou-se a zona de ablação tecidual, zona de necrose térmica, presença e característica das células inflamatórias e o processo de reparo. A peça de mão 2051 foi a que propiciou corte mais rápido e produziu bordas de ferida mais definidas. Para realizar uma incisão de 1.30 mm de profundidade foi necessário passar as peças de mão do laser cinco vezes no mesmo local. Não houve diferença no processo de reparo nas incisões realizadas com os três tipos de peças de mão do laser de Erbio Yag

The study analised microscopic wound healing of incision made with Er:YAg laser with three different tips. In six Rattus norvegicus, incision was made with Laser Er-YAG (KeyLaser) using tips 2051, 2055 and 2056. The animals were killed at 7 e 14 and the sites of incision are photographed in this time. The parts containing the incision area were prepared for microscopic analysis, performing sections of 7µm and staining with haematoxylin and eosin. Zone of tissue ablation, zone of thermal necrosis, the presence and character of inflammatory cell infiltrate and wound healing were measured. The 2051 tip produced faster and defined edges of the wound. To create wound 1.30 mm in depth lasers tips required at last five passes within the same line of incision. Microscopic analysis shows no difference with use of three different laser tips

Biocompatibility and setting time of CPM-MTA and white Portland cement clinker with or without calcium sulfate

Objective: To evaluate the biocompatibility and the setting time of Portland cement clinker with or without 2% or 5% calcium sulfate and MTA-CPM. Material and Methods: Twenty-four mice (Rattus norvegicus) received subcutaneously polyethylene tubes filled with Portland cement clinker with or without 2% or 5% calcium sulfate and MTA. After 15, 30 and 60 days of implantation, the animals were killed and specimens were prepared for microscopic analysis. For evaluation of the setting time, each material was analyzed using Gilmore needles weighing 113.5 g and 456.5 g, according to the ASTM specification Number C266-08 guideline. Data were analyzed by ANOVA and Tukey's test for setting time and Kruskal-Wallis and Dunn test for biocompatibility at 5% significance level. Results: Histologic observation showed no statistically significant difference of biocompatibility (p>0.05) among the materials in the subcutaneous tissues. For the setting time, clinker without calcium sulfate showed the shortest initial and final setting times (6.18 s/21.48 s), followed by clinker with 2% calcium sulfate (9.22 s/25.33 s), clinker with 5% calcium sulfate (10.06 s/42.46 s) and MTA (15.01 s/42.46 s). Conclusions: All the tested materials showed biocompatibility and the calcium sulfate absence shortened the initial and final setting times of the white Portland cement clinker.

In vivo accuracy of conventional and digital radiographic methods in confirming root canal working length determination by Root ZX

OBJECTIVES: To compare, in vivo, the accuracy of conventional and digital radiographic methods in determining root canal working length. MATERIAL AND METHODS: Twenty-five maxillary incisor or canine teeth from 22 patients were used in this study. Considering the preoperative radiographs as the baseline, a 25 K file was inserted into the root canal to the point where the Root ZX electronic apex locator indicated the APEX measurement in the screen. From this measurement, 1 mm was subtracted for positioning the file. The radiographic measurements were made using a digital sensor (Digora 1.51) or conventional type-E films, size 2, following the paralleling technique, to determine the distance of the file tip and the radiographic apex. RESULTS: The Student "t" test indicated mean distances of 1.11 mm to conventional and 1.20 mm for the digital method and indicated a significant statistical difference (p<0.05). CONCLUSIONS: The conventional radiographic method was found to be superior to the digital one in determining the working length of the root canal.

Analysis of accuracy of endodontic millimeter rulers of different commercial brands / Análise da precisão das réguas endodônticas milimetradas de diferentes marcas comerciais

Objective: Evaluate the accuracy of the Brazilian market of endodontic millimeter rulers. Methods: The endodontic millimeter rulers were divided into four experimental groups of 10 rulers each, according to the commercial brand: Group 1 - Jon (Comércio de Produtos Odontológicos Ltda., São Paulo, Brazil), Group 2 - Microdont (Microusinagem de Precisão Ltda., Socorro, Brazil), Group 3 - Angelus (Angelus Soluções Odontológicas, Londrina, Brazil) e Group 4 - ICE (Instrumentos Cirúrgicos Esmeralda Ltda., São Paulo, Brazil). In each endodontic ruler the measure of 20.00 mm was verified with an electronic digital caliper. The results were statistically tested using variance analysis ANOVA followed by Turkey test with p <0.05. Results: The results showed that the average measures of the rulers are not exact, ranging from 19.80 mm to 20.27 mm for the brand ICE (Instrumentos Cirúrgicos Esmeralda Ltda., São Paulo, Brazil). The brand Angelus (Angelus Soluções Odontológicas, Londrina, Brazil) had the lowest variation and exact measurement in 60% of rulers examined. There was no significant difference between brands.Conclusion: The endodontic millimeter rulers analyzed were not standardized and accurate, so the professional should use the same ruler from the beginning to the end of the treatment.

Objetivo: Avaliar a precisão de réguas endodônticas milimetradas comercializadas no Brasil. Métodos: As réguas endodônticas milimetradas foram divididas em 4 grupos experimentais de 10 réguas cada, de acordo com a marca comercial: Grupo 1 - Jon (Comércio de Produtos Odontológicos Ltda., São Paulo, Brasil), Grupo 2 - Microdont (Microusinagem de Precisão Ltda., Socorro, Brasil), Grupo 3 - Angelus (Angelus Soluções Odontológicas, Londrina, Brasil) e Grupo 4 - ICE (Instrumentos Cirúrgicos Esmeralda Ltda., São Paulo, Brasil). Em cada régua foi aferida a medida de 20,00mm por meio de um paquímetro digital eletrônico. Os resultados obtidos foram submetidos à análise estatística utilizando Análise de Variância ANOVA, seguido do teste de Turkey com p<0,05. Resultados: Os resultados demonstraram que a média das medidas das réguas não são exatas, variando desde 19,80mm até 20,27mm para a marca ICE (Instrumentos Cirúrgicos Esmeralda Ltda., São Paulo, Brasil). A marca Angelus (Angelus Soluções Odontológicas, Londrina, Brasil) apresentou a menor variação e a medida exata em 60% das réguas examinadas. Não houve diferença significante entre as marcas. Conclusão: As réguas endodônticas milimetradas analisadas, não se mostraram padronizadas e precisas, devendo o profissional utilizar a mesma régua do início ao fim do tratamento.

Influence of root canal sealer on the radiographic appearance of filling voids in maxillary single-rooted teeth

OBJECTIVE: This study compared the influence of three epoxy resin-based sealers with distinct radiopacities on the observers' ability to detect root canal filling voids during radiographic analysis. MATERIAL AND METHODS: The root canals of 48 extracted maxillary canines were prepared and divided into three groups. Each group was laterally condensed with one sealer (AH Plus®, Acroseal® or a non-radiopaque sealer), and a longitudinal void was simulated in half of the specimens from each group (n=8). Buccolingual radiographs were obtained and randomly interpreted for voids by a radiologist and an endodontist in a blinded fashion. Teeth were cut and inspected under a microscope to confirm the position of void. Differences in sensitivity and specificity between groups and examiners were compared using the Fisher's Exact and McNemar tests, respectively (α=0.05). RESULTS: Significantly lower sensitivity levels (p<0.05) were observed in the coronal portion of fillings performed with both radiopaque sealers. Specificity values for Acroseal® were significantly higher (p<0.05) in the coronal and apical portions of fillings. CONCLUSIONS: The type of root canal sealer can affect the observers' ability to detect root canal filling voids during radiographic analysis of upper single-rooted teeth.

Biocompatibilidade e tempo de presa do clinker do cimento Portland cinza, com ou sem sulfato de cálcio

Objetivo: avaliar a biocompatibilidade do clinker do cimento Portland cinza, sem e com 2% e 5% de sulfato de cálcio. Métodos: vinte e quatro ratos receberam implantes no tecido subcutâneo, de tubos de polietileno preenchidos com o pó do clinker do cimento Portland cinza, sem ou com 2% e 5% de sulfato de cálcio. Após 15, 30 e 60 dias da implantação, os animais foram mortos e os espécimes preparados para a análise microscópica.Os tempos de presa de cada material foram avaliados de acordo com as especificações n° C266-08 da ASTM. Os dados foram analisados pelos testes ANOVA e de Tukey, para o tempo de presa; e pelo de Kruskal-Wallise de Dunn para a biocompatibilidade, com nível de significância de 5%. Resultados: histologicamente, não se constatou diferença estatística entre os materiais. Conclusão:o clinker sem sulfato de cálcio apresentou tempo de presa inicial de 5 min. e final de 55 min., seguido pelo clinker com 2% de sulfato de cálcio (8-95 min.) e pelo clinker com 5% de sulfato de cálcio (10-110 min.)

Uso de protetor gengival para isolamento apical em cirurgia parendodôntica / Use of gum protector for apical isolation in endodontic surgery

Para a realização da obturação retrógrada é necessário que o ápice radicular esteja livre de sangue ou umidade. A utilização do protetor gengival em cavidades cirúrgicas foi sugerida para facilitar procedimentos cirúrgicos no ápice radicular. Este trabalho apresenta a técnica de utilização do protetor gengival para isolamento apical em cirurgia parendodôntica

To perform the retrograde filling, it is necessary that the apex is free of blood or moisture. The use of gum protector in surgical cavities has been proposed to facilitate surgical procedures in the apex. This paper presents the technique for use of gum protector material for apical isolation in endodontic surgery

Removal efficiency of propolis paste dressing from the root canal

OBJETIVES: The aim of this study was to investigate through scanning electron microscopy (SEM) the cleaning of root canal walls after the use of experimental propolis or calcium hydroxide root canal dressings. MATERIAL AND METHODS: Twenty single-rooted teeth were used. After conventional cleaning and shaping procedures and removal of the smear layer with 17 percent EDTA, the teeth were divided into four groups according to the medication used (N=5): Group I (control) - No drug, Group II - Calcium hydroxide dressing, Group III - Propolis paste A70D and Group IV - Propolis paste D70D. The medications were introduced into the root canals and maintained for 7 days, then removed with a K-file and 5 mL of 1 percent sodium hypochlorite irrigation. Finally, the canals were flushed with 2 mL of 17 percent EDTA for 3 min. For SEM analysis, the roots were cleaved and microphotographs from the middle third of the root canal were taken at 750x. The cleaning of the root canal walls was determined by the number of open dentinal tubules as verified with the software Image Tool 3.1. The statistical analysis was performed by ANOVA and Tukey's test (p<0.05). RESULTS: The results showed no statistically significant difference between the calcium hydroxide and propolis groups. CONCLUSIONS: The experimental propolis pastes presented acceptable physical characteristics to be used as intracanal medicaments.

SAF (self adjusting file) um novo conceito na instrumentação dos canais radiculares / SAF (self adjusting file) a new concept in root canal preparation

A instrumentação dos canais radiculares tem sofrido uma série de inovações tanto quanto aos instrumentos como às técnicas. Com o advento dos instrumentos de níquel-titânio o mercado tem recebido uma grande variedade de novos instrumentos. Recentemente um novo sistema foi introduzido no mercado, o SAF (Self Adjusting file) ou lima auto ajustável. Este artigo tem o objetivo de apresentar esse novo instrumento.

The instrumentation of root canals has suffered a series of innovations to instruments as well as techniques. With the advent of nickel-titanium instruments of the market has received a variety of new instruments. Recently a new system was introduced in the market, SAF (Self Adjusting file). This article aims to present this new instrument.

Rins endo: um novo sistema para irrigação dos canais radiculares / Rins endo: a new system for irrigation of the root canals

A completa limpeza do sistema de canais radiculares, por meio da instrumentação e irrigação, é um fator importante no sucesso na terapia endodôntica. Além de novos instrumentos, novos dispositivos foram desenvolvidos para irrigação dos canais radiculares, destacando, entre eles, o sistema Rins Endo com ativação hidrodinâmica baseado na tecnologia de pressão-sucção. A finalidade deste trabalho é descrever os componentes desse novo sistema e a técnica para sua utilização.

In the attempt to reach the complete cleanness of the root canals system and to increase the success in the endodontics therapy, new devices had been developed to irrigation of root canals, amongst them, the Rins Endo system, with hydrodynamic activation based in the pressure-suction technology. This system is a alternative to the endodontics during the biomechanical preparation. The objective of this work was to describe the components of this new system and the technique for its use.

Avaliação de cavidades apicais realizadas com pontas ultrassônicas lisas, diamantadas e combinação de ambas / Evaluation of apical cavity preparation with ultrasonic, stainless steel, diamond coated lips and both

OBJETIVO: O objetivo deste trabalho foi avaliar, por meio do microscópio clínico e eletrônico devarredura, as paredes de cavidades apicais, as irregularidades produzidas com as pontas ultrassônicas diamantadas,lisas e com a combinação de ambas. MATERIAL E MÉTODO: Dezoito dentes pré-molaresinferiores de humanos, com apenas um conduto, foram apicetomizados e, no ápice, foram realizadascavidades para obturação retrógrada divididas em três grupos: grupo 1: cavidades preparadas com pontaultrassônica lisa; grupo 2: cavidades preparadas com ponta ultrassônica diamantada e grupo 3: cavidadespreparadas, iniciando com a ponta diamantada e seguida pela lisa. As paredes das cavidades foramobservadas inicialmente sob microscópio clínico e, a seguir, os ápice foram seccionados, metalizados eanalisados no microscópio eletrônico de varredura, atribuindo-se-lhes os seguintes escores: 1 - adequada;2 - regulares e 3 - irregulares. RESULTADOS: A ponta diamantada produziu 3 cavidades adequadas, 2regulares e 1 irregular; a ponta lisa, 5 adequadas, 1 regular e nenhuma irregular. A associação de ambaspropiciou 2 cavidades adequadas, 3 regulares e 1 irregular. CONCLUSÃO: Não houve diferença estatísticana qualidade das cavidades preparadas com pontas lisas, diamantadas ou na associação das duas. Quanto àavaliação realizada com os microscópios clínico e o de varredura, não houve diferença estatística entre eles.

OBJECTIVE: To evaluate the quality of root-end preparations using ultrasonic stainless steel and diamond coated tips used individually or associated. The cavity walls were analyzed using a clinical microscope and by scanning electron microscopy (SEM). MATERIAL AND METHOD: Eighteen single rooted mandibular premolars weresubmitted to apicectomy and root-end cavities were performed using ultrasonic tips. The teeth were divided according to the ultrasonic tip used. Group 1 (n=6) stainless steel tips. Group 2 (n=6) diamond coated tips. Group 3 (n=6) the cavity was done initially with a diamond coated tip and finished using a non-coated tip. Three scores were assigned to evaluate the quality of the cavity walls: 1 adequate; 2 regular; 3 inadequate. RESULTS: Diamond coated tip preparation showed 3 adequate cavities, 2 regulars and 1 inadequate. The stainless steel tip preparation showed 5 adequate cavities and 1 regular. The association of the tips showed 2 adequate cavities, 3 regulars and 1 inadequate. CONCLUSION: There was no statistically difference in the quality preparation for the analyzed groups. There was no statistically difference in the evaluation using a clinical microscope or SEM.

Effect of calcium hydroxide-based dressing on apical sealing in immature teeth filled with MTA / Efeito da medicação à base de hidróxido de cálcio no selamento apical de dentes imaturos obturados com MTA

OBJECTIVES: To evaluate the effects of a calcium hydroxide-based intracanal dressing on the initialapical adaptation and leakage of fillings performed with mineral trioxide aggregate (MTA) in teeth withopen apices. STUDY DESIGN: A total of 24 canals were manually prepared and randomly divided intotwo groups (n = 12). In the experimental group, root canals were dressed with calcium hydroxide-basedpaste for 21 days; in the control group, no medication was applied prior to the filling of root canalswith mineral trioxide aggregate. Apical sealing was evaluated on the basis of rhodamine B penetrationand the detection of microscopic apical defects at the filling interface (SEM). The data obtained werecompared by means of t- and Fisher’s Exact tests (á = 0.05). RESULT S: The difference in mean dyeleakage between the experimental (5.03±1.97 mm) and control (4.14±1.13 mm) groups was not statisticallysignificant (ñ < 0.05). The number of microscopic fissures at the experimental group interface (2/12)was significantly lower than that observed for the control group (9/12) (ñ < 0.05). CONCLUSIONS:The use of a calcium hydroxide-based intracanal dressing did not interfere with the initial apical sealingof immature teeth filled with MTA.

OBJETIVOS: Avaliar os efeitos da medicação intracanal à base de hidróxido de cálcio sobre a adaptação apical inicial e selamento de obturações realizadas com agregado de trióxido mineral (MTA) em dentes com ápice aberto. PLANEJAMENTO DO ESTUDO: Um total de 24 canais foram manualmente preparados e aleatoriamente divididosem dois grupos (n = 12). No grupo experimental, canais radiculares foram preenchidos com pasta à base de hidróxido de cálcio por 21 dias; no grupo controle, nenhuma medicação foi aplicada antes da obturação dos canais com agregado de trióxido mineral. O selamento apical foi avaliado com base na penetração de rodamina B e na detecção microscópica de defeitos apicais na interface das obturações (MEV). Os dados obtidos foram comparados por intermédio dos testes “t” e Exato de Fisher (α = 0,05). RESULTADOS: A diferença nos níveis médios de infiltraçãoentre os grupos experimental (5.03±1.97 mm) e controle (4.14±1.13 mm) não se mostrou estatisticamente significante (ρ < 0,05). O número de fendas microscópicas na interface das obturações do grupo experimental (2/12) apresentou-se estatisticamente inferior ao detectado para o grupo controle (9/12) (ρ < 0,05). CONCLUSÕES: O uso de medicação intracanal à base de hidróxido de cálcio não interferiu no selamento apical inicial de dentes imaturos obturados com MTA.

Capacidade de limpeza de alguns agentes auxiliares do preparo biomecânico em dentes portadores de canais laterais (Estudo em microscopia eletrônica de varredura) / Cleaning efficiency assessment of some auxiliary substances during the preparation of teeth with lateral canals (a SEM study)

O objetivo deste trabalho foi avaliar a eficiência de limpeza de diferentes substâncias irrigadoras auxiliares durante o preparo biomecânico em dentes portadores de canais laterais. Foram utilizados 40 dentes pré-molares inferiores humanos recém-extraídos, com canal único. Confeccionou-se em cada dente, três canais laterais (terços cervical, médio e apical). Os dentes foram divididos em quatro grupos, em função das substâncias utilizadas: Grupo I-Hipoclorito de sódio a 1% + EDTA; Grupo II-Endo-PTC + hipoclorito de sódio a 0,5%; Grupo III-File-Eze; Grupo IV-Clorexidina a 2%, em forma de gel. O preparo biomecânico dos canais radiculares foi realizado utilizando o sistema de instrumentação rotatória, Profile 0.04, técnica “crown-down”. Apos o preparo dos canais as raízes foram seccionadas longitudinalmente e então preparadas para análise das paredes dos canais em microscopia eletrônica de varredura, a qual se analisou a obstrução ou não dos canais laterais.O hipoclorito de sódio associado ao EDTA propiciou menor obstrução dos canais laterais; mais obstruções ocorreram no terço apical.

The aim of this work was to assess the cleaning efficiency of different auxiliary substances during the biomechanical preparation of teeth with lateral canals. 40 human lower pre-molar teeth with just one canal were used; three lateral canals (cervical, mid and apical thirds) were made in each tooth. The teeth were divided into 4 groups of 10 specimens each according to the substance used: Group I-1% sodium hypochlorite + EDTA; Group II-Endo-PTC + 0,5% sodium hypochlorite; Group III-File-Eze; Group IV-2% Chlorexidine gel. The root canal biomechanical preparation was carried out using rotating instrumentation, Profile 04 with “crown-down” technique.The teeth were split along their long axis in a buccolingual direction and prepared for scanning electron microscopic analysis. The results concluded that the sodium 1% sodium hypochlorite + EDTA showed best cleaning of lateral canal; apical third showed most obstruction of lateral canal.

Avaliação da adaptação de diferentes materiais às paredes de cavidades retrógradas por meio de microscopia eletrônica de varredura / Marginal adaptation in root-end cavities of different root end filling materials: a SEM study

O objetivo deste trabalho foi avaliar, in vitro, a adaptação de diferentes materiais retro-obturadores às paredes de cavidades retrógradas. Foram utilizados 60 caninos superiores humanos, que, após a obturação dos canais foram apicetomizados perpendicularmente à raiz a 3mm do ápice radicular. Foram preparadas cavidades apicais com 3mm de profundidade, utilizando broca esférica nº 3. As cavidades foram retroobturadas com Super EBA, Polímero de Mamona, Vidrion Endo, Ketac Endo, MTA Pro Root e cimento Portland branco. Os ápices radiculares foram moldados com silicona de condensação. Tanto os moldes, como os ápices foram analisados em microscopia eletrônica de varredura. O cimento Portland branco, e o EBA apresentaram a melhor adaptação às paredes das cavidades.

The aim of this study was to analyze the marginal adaptation of retro-fillings materials using Scanning Electron Microscopy (SEM). The sample consisted of 60 human canines, in wich apicoectomy was performed on the three final millimeters and three millimeters deep retro-preparation was achieved through round burs. The specimens were divided in 6 groups and retrofilled with super EBA, Castor oil polymer, Vidrion Endo, Ketac Endo, MTA ProRoot, Portland white cement. Resected root apices with retro preparation and their respective impressions were examined by means of SEM magnified 50 times to allow measurement of occasional gaps between the filling material and tooth walls. Portland cement and EBA show good adaptation in walls of retro filling cavities.

Sealing ability, marginal adaptation and their correlation using three root-end filling materials as apical plugs

OBJECTIVE: This study used dye leakage assay and scanning electron microscopy to evaluate, respectively, the sealing ability and marginal adaptation of three root-end filling materials used as apical plugs, as well as the possible correlation between these properties. MATERIAL AND METHODS: Ninety-eight single-rooted human teeth were prepared to simulate an open apex. The teeth were allocated to three experimental groups (n = 30), which received a 5-mm thick apical plug of (1) gray MTA AngelusTM, (2) CPM TM and (3) MBPc, and two controls groups (n = 4). After immersion in 0.2 percent Rhodamine B solution for 48 h, the teeth were sectioned longitudinally and analyzed by Image Tool 3.0 software. The marginal adaptation between apical plugs and the root canal walls were analyzed by SEM. RESULTS: MBPc had significantly less (p<0.05) apical leakage than the other materials. Regarding marginal adaptation, CPM TM showed the best numerical results, though without statistical significance from the other materials (p<0.05). There was no correlation between the two properties. CONCLUSIONS: When used as apical plugs, the tested root-end filling materials had similar marginal adaptation to the dentin walls, but MBPc had the best sealing ability, as demonstrated by the least apical leakage from all tested materials.