RESUMO Objetivo: Comparar a acurácia do diagnóstico precoce de reabsorções radiculares interna (RRI) e reabsorções radiculares externa (RRE) simuladas, por meio de radiografia periapical digital e tomografia computadorizada de feixe cônico. Métodos: Reabsorções radiculares foram simuladas em dentes humanos extraídos utilizando a desmineralização com ácido nítrico 5% e hipoclorito de sódio 8% em diferentes períodos (1 e 5 dias). Para o grupo reabsorções radiculares externa (n=12) cilindros de resina composta foram posicionados no terço médio das faces vestibulares das raízes, delimitando a aplicação das substâncias de desmineralização. No grupo reabsorções radiculares interna (n=12) os dentes foram seccionados longitudinalmente, e os cilindros de resina posicionados no terço médio dos canais radiculares. Os dentes foram montados em mandíbula seca e avaliados por meio de radiografia digital e tomografia por dois examinadores. Resultados: Nas imagens tomográficas no período de 1 dia, o examinador 2 identificou reabsorções radiculares interna as quais não foram identificadas nas radiografias (p<0,05). Nenhum examinador foi capaz de diagnosticar as reabsorções radiculares externa independente do exame no grupo de 1 dia (p>0.05). No período de indução de 5 dias ambos os exames identificaram as reabsorções radiculares interna (p>0,05), entretanto, as tomografias foram mais eficazes na identificação das reabsorções radiculares externa (p<0,05) para ambos os examinadores. Conclusão: A tomografia computadorizada de feixe cônico mostrou-se mais eficaz do que a radiografia periapical digital na detecção de reabsorções radiculares interna com 1 dia de indução. Os recursos imaginológicos utilizados neste estudo não foram capazes de detectar precocemente a reabsorção radicular externa.

ABSTRACT Objective: Compare the accuracy of early diagnosis of simulated internal root resorptions and external root resorption, using digital periapical radiography and cone beam computed tomography. Methods: Root resorption were simulated in extracted human teeth by demineralization with 5% nitric acid solution and 8% Sodium Hypochlorite in different periods (1 and 5 days). For the group external root resorption (n=12) composite resin cylinders were positioned on middle third of buccal surface of roots, to delimit application of demineralization substances. In group internal root resorptions (n=12) the teeth were sectioned longitudinally, and the composite resin cylinders were positioned in the middle third of root canals. The teeth were mounted in a dry mandible and evaluated by digital radiography and tomography. The images were evaluated by two examiners. Results: Analyzing the tomographic images in period of 1 day, the examiner 2 identified internal root resorptions that were not identified in radiographic images (p<0.05). No examiner was capable of diagnosing external root resorption irrespective of exam, in the group of 1 day (p>0.05). In 5 day period of induction, both exams identified internal root resorptions (p>0.05), however, the tomographic images were more effective in identifying external root resorption (p <0.05) for both examiners. Conclusion: Cone beam computed tomography was shown to be more effective than digital periapical radiography for detecting internal root resorptions with 1 day of induction. The imaginological resources used in this study were not able to early detect external root resorption.

OBJETIVO: Avaliar in vitro a capacidade seladora de três materiais utilizados como barreira cervical durante o clareamento interno. MÉTODOS: Foram selecionados trinta e três caninos humanos, que após o preparo biomecânico dos canais radiculares, foram obturados pela técnica da condensação lateral ativa. Após a reação de presa do material obturador os dentes foram divididos aleatoriamente em três grupos de dez dentes cada, de acordo com os seguintes materiais para confecção da barreira cervical: X Temp LC; Vitro Fil; Coltosol. O grupo controle constituiu de três dentes sem a confecção do tampão cervical. Utilizou-se como substância clareadora o Perborato de Sódio/ água destilada associado à Rodamina B 2%. Após a colocação do agente clareador na câmara pulpar, as aberturas coronárias foram seladas com cimento provisório IRM e as amostras foram armazenadas em estufa a 37° por 7 dias. Após esse período, as amostras foram clivadas no sentido longitudinal, e a avaliação da infiltração foi realizada pelo método visual. Os dados foram submetidos ao teste estatístico de Kruskal-Wallis, com nível de significância de 5%. RESULTADOS: Não houve diferença estatisticamente significante entre os grupos de estudo, embora o Coltosol tenha obtido maior número de espécimes com menor grau de infiltração. CONCLUSÃO: Todos os materiais avaliados na confecção do tampão cervical permitiram algum nível de infiltração.

OBJECTIVE: To evaluate in vitro the sealing ability of three materials used as cervical barrier for internal dental bleaching. METHODS: Thirty-three canines were selected, and after biomechanical root canal preparation, the canals were filled by lateral condensation technique. After the filling material setting reaction, the teeth were randomly divided into three groups of ten teeth each, according to the following materials for constructing the cervical barrier: X Temp LC; Vitro Fil; Coltosol. The control group consisted of three teeth, without placement of the cervical cap. Sodium perborate /distilled water associated with 2% Rhodamin B were used as bleaching substance. After placing the bleaching agent in the pulp chamber, access cavities were sealed with temporary cement IRM and samples were stored at 37 ° for 7 days. After this period, the samples were cleaved longitudinally, and leakage was evaluated by the visual method. The data were submitted to Pearson test with a 5% level of significance. RESULTS: No statistically significant difference was found between the study groups, however, the largest number of specimens with a lower degree of leakage were found in the Coltosol group. CONCLUSION: All the materials evaluated for making the cervical cap allowed some level of leakage.

OBJECTIVE: The aim of this study was to evaluate the biomechanical preparation of flattened root canals using the following systems: Endo-Eze AET stainless steel oscillatory instruments (Ultradent) and RaCe rotary NiTi instruments (FKG Dentaire). MATERIAL AND METHODS: Twenty extracted human mandibular incisors were randomly assigned to two groups: Group 1 - Instrumentation with oscillatory Endo-Eze AET files (oscillatory technique); Group 2 - Instrumentation with rotary NiTi RaCe files (rotary technique). The teeth were decoronated, had their apices and coronal openings sealed with sticky wax and were embedded in crystal-clear orthophtalic polyester resin. The roots were sectioned transversally with diamond discs at 10 mm (middle third) and 5 mm (apical third) from the apex and the segments were reassembled for instrumentation. The sections were photographed before and after root canal instrumentation and evaluated with respect to whether the original root canal shape was modified by instrumentation. To evaluate the differences in the root canal shape before and after biomechanical preparation, scores were given regarding the instruments touch on the intracanal walls. RESULTS: In middle third of the root canals instrumented with the rotary system, there was a change in the original canal anatomy (p<0.05), with formation of a protuberance in the mesiodistal direction. This protuberance did not occur when the oscillatory instrumentation was used. The oscillatory system had better results in the middle and apical thirds as evaluated by Dunn's multiple-comparison test (p>0.05). CONCLUSION: Under the tested conditions, Endo-Eze oscillatory system yielded the instrumentation of all flattened root canal walls, maintaining the canal original shape throughout the biomechanical preparation, and was more effective than RaCe rotary system.