ABSTRACT Objectives This study evaluated the antimicrobial efficacy of ozone therapy in teeth contaminated with Pseudomonas aeruginosa, Enterococcus faecalis, and Staphylococcus aureus using a mono-species biofilm model. Parallel to this, the study aimed to evaluate the cytotoxicity of ozone for human gingival fibroblasts. Material and Methods: One hundred and eighty single-root teeth were contaminated with a mono-species biofilm of Enterococcus faecalis, Pseudomonas aeruginosa, and Staphylococcus aureus. Groups were formed: Group I – control; Group II – standard protocol; Group III – standard protocol + ozone gas at 40 µg/mL; and Group IV – standard protocol + aqueous ozone at 8 µg/mL. In parallel, human gingival fibroblasts were submitted to the MTT test. Cells were plated, then ozone was applied as follows: Group I (control) – broth medium; Group II – aqueous ozone at 2 µg/mL; Group III – aqueous ozone at 5 µg/mL; and Group IV – aqueous ozone at 8 µg/mL. Data were submitted to the Kruskal Wallis test and Bonferroni post hoc analyses to assess microbiology and cytotoxicity, respectively (p<0.05%). Results The results revealed antimicrobial efficacy by Group IV with no CFU count. The cytotoxicity assay showed Groups III and IV to be the most aggressive, providing a decrease in cell viability at hour 0 from 100% to 77.3% and 68.6%, respectively. Such a decrease in cell viability was reverted, and after 72 hours Groups III and IV provided the greatest increase in cell viability, being statistically different from Groups I and II. Conclusion According to the applied methodology and the limitations of this study, it was possible to conclude that ozone therapy improved the decontamination of the root canal ex vivo. Ozone was toxic to the cells on first contact, but cell viability was recovered. Thus, these findings suggest that ozone might be useful to improve root canal results.

This study compared the coronal and apical leakage of AH Plus with gutta-percha to that of Epiphany with Resilon. Twenty-four single rooted teeth were instrumented and divided into 2 groups according to the solutions for smear layer removal and the obturation materials employed: Group A - 17% EDTA-T and AH Plus with gutta-percha; Group B - primer and Epiphany with Resilon. The Group B specimens were light-cured in the coronal area for 20 s. The external root surfaces were covered with a double layer of ethyl cyanoacrylate, except for the apical foramen and the cavity access. The teeth were immersed in 0.5% methylene blue for 48 h. The specimens were rinsed, dried and axially split for dye penetration measurement with the ImageLab 2.3 software. The t-test showed no significant differences for coronal leakage between the groups, but there were significant differences for apical leakage between the groups (P < 0.05). AH Plus with gutta-percha and Epiphany with Resilon provided the same coronal seal, whereas Epiphany with Resilon provided the best apical seal.

A matriz extracelular (MEC) tem um papel importante na regulação do crescimento e na diferenciação e organização dos tecidos. Com base nestes aspectos o objetivo do deste estudo foi analisar o colágeno, maior componente orgânico da MEC da polpa dentária, na papila de germes dentários humanos, em diferentes fases do desenvolvimento. Foram obtidos fragmentos de maxilas e mandíbulas de 9 fetos humanos com 10 a 22 semanas de vida intra-uterina, dos quais foram analisados 16 germes dentários (1 em estágio de capuz, 8 em estágio de campânula precoce e 7 em estágio de campânula tardia). Secções histológicas seriadas foram coradas com hematoxilina e eosina, tricrômico de Masson e técnica de coloração do picrosirius. Ambos os tipos de colágeno na papila dentária foram somente detectados pela técnica de coloração do picrosirius usando microscopia de luz polarizada. Colágeno tipo III foi detectado em todas as amostras. Colágeno tipo I estava presente em áreas focais da papila dental em algumas amostras. Concluiu-se que o colágeno tipo III mostrou-se um componente regular da papila de germes dentários humanos, enquanto o colágeno tipo I esteve presente em quantidade significativamente menor.

The extracellular matrix (ECM) performs a very important role in growth regulation and tissue differentiation and organization. In view of this, the purpose of this study was to analyze the collagen, the major organic component of dental pulp ECM, in papillae of human tooth germs in different developmental phases. The maxillas and mandibles of 9 human fetuses ranging from 10 to 22 weeks of intrauterine life were removed and 16 tooth germs (1 in the cap stage, 8 in the early bell stage and 7 in the late bell stage) were obtained. The pieces were processed for histological analysis and stained with hematoxylin-eosin, Masson's Trichrome and picrosirius staining technique. Both types of collagen in the dental papilla were only detected by the picrosirius staining technique under polarized light microscopy. Type III collagen was detected in all specimens. Type I collagen was present in focal areas of the dental papilla only in some specimens. In conclusion, the findings of this study showed that type III collagen is a regular component of the papillae of human tooth germs whereas type I collagen is present in a significantly lesser amount.

O selamento do sistema de canais radiculares é de fundamental importância para o sucesso do tratamento endodôntico. Para um adequado selamento apical, devemos considerar, entre outros fatores, a presença da smear layer e o cimento obturador empregado. Após o preparo do canal, esta camada deve ser removida pois, entre outros fatores, impede contato íntimo entre a parede dentinária e o material obturador. O objetivo deste trabalho foi avaliar a capacidade seladora de quatro diferentes cimentos obturadores após remoção da smear layer com irrigação com EDTA-T a 17% ou irradiação com laser Er:YAG. Os 46 dentes humanos foram instrumentados e a smear layer foi removida por irrigação com EDTA-T ou irradiação com laser Er:YAG. Os canais foram obturados com 4 diferentes cimentos obturadores: Sealapex, Ketac Endo, AH Plus e N-Rickert. O método de remoção da smear layer não interferiu no selamento apical. Quanto aos cimentos testados, o AH Plus e o N-Rickert permitiram menos infiltração do corante quando comparados aos cimentos Sealapex e Ketac Endo.

The sealing of the root canal system is of fundamental importance for successful endodontic treatment. To obtain an adequate apical seal, many factors must be considered such as the presence of smear layer and the sealer applied. After canal preparation, this layer must be removed because it prevents close contact between the dentinal walls and the sealing material. The goal of this study was to evaluate the sealing ability of four different sealers after smear layer removal with either 17% EDTA-T irrigation or Er:YAG laser irradiation of 46 teeth. The canals were sealed with four different sealers: Sealapex, Ketac Endo, AH Plus and N-Rickert. The method for smear layer removal did not influence apical sealing. AH Plus and N-Rickert allowed less dye leakage when compared to Sealapex and Ketac Endo.

É a partir da instrumentação que o canal radicular adquire a forma necessária à adaptação perfeita do material obturador. Durante essa fase, é necessário que ocorra uma interação entre instrumento e canal radicular com vistas a reduzir o número de alterações decorrentes desse passo improcedente. Neste estudo, procurou-se observar a ação de dois tipos de instrumentos endodônticos mecânico-rotatórios: as limas Quantec series 2000 tipo SC, com ponta cortante, e tipo LX, com ponta embotada, na instrumentação de canais simulados com curvaturas entre 20 e 35 graus, valendo-se da técnica Quantec Graduating TapersTM. Os resultados evidenciaram que a média de alteração da curvatura dos canais do Grupo I, que foram instrumentados com limas SC, foi 2,15%; para os canais do Grupo II, instrumentados com limas LX, foi de 2,61%. Embora tenha-se verificado que os canais do Grupo I apresentaram menor percentagem de alteração da curvatura, o teste estatístico pertinente de Mann-Whitney demonstrou não existir diferença significante para ± 5% entre os dois grupos experimentais.

After instrumentation, the root canal acquires the necessary shape for a perfect adaptation of filling material. During this phase cutting end and LX type an interaction between instrument and root canal is necessary in order to reduce alterations that could occur at this point. This study evaluated the action of two mechanical-rotatory endodontic instruments, Quantec files 2000 serie type SC with blunt end, during the instrumentation of simulated canals curved between 20 and 35 degrees, using quantec graduating tapers. Results showed that the mean curvature alteration of group I canals that were instrumented with SC files, was 2,15%, and for group II instrumented with LX files, was 2,61%. Furthermore group I canals showed lower percentage of curvature alteration. Mann-Whitney tests showed no significant statistical difference at 5% between experimental groups.

Buscou-se avaliar, após o preparo químico-cirúrgico, a modificação do ângulo de curvatura de canais radiculares simulados, confeccionados em blocos de resina epóxica com curvaturas de 35 graus, instrumentados acorde técnica seriada de Paiva & Antoniazzi, usando-se limas tipo K e Flexofile pré-curvadas e retas e limas Nitiflex. Os resultados mostraram que a menor alteração da curvatura foi provocada pela lima Flexofile pré-curvada, seguida da lima Nitiflex e da lima tipo K pré-curvada. Os canais instrumentados com lima tipo K e Flexofile retas mostraram as maiores deformações angulares. A pré-curvatura influencia na deformação dos canais, uma vez que houve diferenças estatísticas significantes entre os valores obtidos pelas limas Flexofile e tipo K pré-curvada ou não.

Chemical-surgical preparation (C.S.P.) is responsible for shaping and cleaning the root canal, being these the main requirements for a correct filling procedure. Therefore, this study attempted to evaluate the change of curvature angle of simulated root canals after chemical-surgical preparation. These root canals were made in blocks of epoxy resin with curvatures of 35 degrees, and instrumented according to the serial technique of Paiva and Antoniazzi, using type-K files, Flexofile files (pre-curved and straight) and Nitiflex files. The results showed that the smallest alteration in curvature was caused by the pre-curved Flexofile files, followed by Nitiflex files and pre-curved type-K files. The root canals instrumented with straight type-K and Flexofile files showed the largest deformation in curvature. The pre-curvature of the files affects the deformation of the root canals, presenting statistically significant differences between the results obtained with straight and pre-curved Flexofile and type-K files.

O estudo das imagens do dente em tratamento endodôntico e das suas estruturas anexas favorece a identificação precoce das alterações capazes de comprometer o prognóstico de sucesso. A perfeita informação radiográfica e a correta interpretação comprovadamente orientam a conduta terapêutica, estreitando a relação entre a cura e a patologia. Assim sendo, e devido à importância da fidelidade desse procedimento, os autores apresentam um dispositivo que, acoplado a qualquer posicionador comercializado, possibilita a tomada de imagens semelhantes sob o aspecto das suas dimensões. A importância desse fato surgiu da necessidade do confronto das imagens obtidas entre as sessões do tratamento. Os estudos clínicos indicaram que o posicionador personalizado obtido através de moldagem com material pesado favoreceu sensivelmente as análises comparativas das áreas da superfície radicular externa acometidas de reabsorção cemento-dentinária, como seqüela de trauma dental, bem como as regiões portadoras de rarefação óssea periapical no decorrer da avaliação da neoformação.

The study of images of teeth under endodontic treatment, as well as neighboring structures, favours the early identification of the alterations that may jeopardize a prognosis of success. The perfect radiographic information and the correct interpretation guide the therapeutic approach, enhancing the relationship between pathology and healing. Due to the importance of this procedure, the authors show an instrument that, coupled to any commercial positioner, allows similar image taking under the aspect of its dimensions. The importance of this fact derived from the need of comparing the images obtained during treatment. Clinical studies indicated that the customized positioner, obtained by means of impression with heavy material, increasingly benefited the comparative analysis of areas on the external root surface with cementum-dentin resorption, such as dental trauma sequela and regions with periapical bone rarefaction during the evaluation of the new bone formation.