Resumo Este estudo avaliou quantitativamente a quantidade de material extruído apicalmente pela instrumentação com lima única reciprocante, aplicando diferentes comprimentos de trabalho e tamanhos de preparo apical. Para a análise de extrusão foram utilizados oitenta incisivos inferiores unirradiculares humanos. Cavidades de acesso convencionais foram preparadas e os espécimes foram divididos em quatro grupos (n=20), de acordo com o tipo de instrumentação do canal: Reciproc 25, 0.08 e Reciproc 40, 0.06 foram utilizadas na instrumentação até o forame; Reciproc tamanho 25, 0.08 e Reciproc 40, 0,06 foram utilizadas na instrumentação até 1 mm aquém do forame. Água destilada foi empregada como irrigante e o material extruído apicalmente foi coletado em frascos de vidro já pesados e posteriormente submetidos a secagem. O peso médio de detritos foi avaliado com uma microbalança de precisão e os dados submetidos a ANOVA e teste Tukey (p<0,05). Todos os grupos experimentais foram associados à extrusão de debris. Nenhuma diferença significativa foi encontrada na quantidade de material extruído apicalmente entre os grupos (p>0,05). Este estudo demonstrou que o comprimento de trabalho e o tamanho do preparo apical não geraram efeito significativo sobre a extrusão de debris durante a instrumentação reciprocante.

Abstract The aim of this study was to quantitatively evaluate the amount of apically extruded debris by single-file reciprocating instruments with different working lengths and apical preparation sizes. Eighty human single-rooted mandibular incisors were used and conventional access cavities were prepared. Then, the specimens were divided into four groups (n=20), according to root canal instrumentation: Reciproc size 25, .08 taper and Reciproc size 40, .06 taper instruments were used at the foramen; Reciproc size 25, .08 taper and Reciproc size 40, .06 taper instruments were used 1 mm short of the foramen. Distilled water was used as an irrigant and the apically extruded debris were collected in pre-weighted glass vials and dried afterwards. The mean weight of debris was weighed with a microbalance and statistically analyzed using one-way analysis of variance and the post hoc Tukey multiple comparison test (p<0.05). The results showed that all experimental groups were associated with debris extrusion. No significant difference was found in the amount of apically extruded debris among all experimental groups (p>0.05). The present study demonstrated that the working length and the apical preparation size did not have a significant effect on debris extrusion when performing single-file reciprocating instrumentation.

A taurodontia é consequência de um distúrbio de desenvolvimento em que a bainha epitelial de Hertwig não invagina corretamente em um nível normal, repercutindo em um aumento do corpo e da câmara pulpar de um dente multiradicular, predominantemente molares permanentes, pelo deslocamento do assoalho pulpar no sentido apical. Apesar de clinicamente aparentar-se como um dente normal, esta variação morfológica pode ser diagnosticada por exame radiográfico de rotina evidenciando câmara pulpar aumentadas em tamanho no sentido ápico-oclusal e raízes curtas. Devido a estas alterações anatômicas, o tratamento endodôntico de um elemento com taurodontia se torna um desafio clínico, já que é necessário um cuidado especial na localização e manejo do sistema de canais radiculares. De acordo com o grau de deslocamento apical do assoalho pulpar, a taurodontia pode ser classificada em: hipotaurodontia, mesotaurodontia e hipertaurodontia. O objetivo deste trabalho é relatar o caso clínico de um paciente que necessitou de tratamento endodôntico em um segundo molar inferior com hipertaurodontia.

Taurodontism is the consequence of a developmental disorder in which the invagination of Hertwig's epithelial root sheath doesn't occur at a proper level. As a result, the pulp body and the chamber of a multi-root tooth, usually permanent molar teeth, are enlarged by the apical displacement of the pulp floor. Despite its clinically normal appearance, the morphological variation of this tooth can be diagnosed by a routine radiographic exam that shows enlarged apico-occlusal pulp chamber and short roots. Due to these anatomical variations, endodontic treatment of a taurodontic element is a clinical challenge given the complexity of localization and instrumentation of the root canal system. According to the degree of displacement of the pulp floor, taurodontism can be classified as: hypotaurodontism, mesotaurodontism and hypertaurodontism. This study objective is to report a clinical case of a patient who was submitted to endodontic treatment of the second inferior molar affected by hypertaurodontism.

The purpose of this study was to compare the efficacy of reciprocating and rotary techniques for removing gutta-percha and sealer from root canals. Forty straight and oval single-rooted premolars were prepared up to size 30, filled with gutta-percha and sealer, and then randomly allocated to two experimental retreatment groups: ProTaper Retreatment System (PTRS) and WaveOne System (WS). Procedural errors, time of retreatment and apically extruded material were recorded for all the roots. The roots were radiographed after retreatment. The percentage of residual material was calculated using image analysis software. The data were analyzed by Kolmogorov-Smirnov and t tests, with a significance level set at 5%. No system completely removed the root filling material from the root canal. No significant differences were observed between the systems, in terms of residual filling material in any tested third (p > 0.05). WS was faster in removing filling material than PTRS (p< 0.05). Extrusion was observed in 4 cases in PTRS and in 5 cases in WS. No procedural errors were observed in either group. It can be concluded that although no differences were observed in the efficacy of PTRS and WS for removing root filling material, WS was faster than PTRS.

A terapia fotodinamica (PDT) tem demonstrado ser eficaz na desinfeccao de canais radiculares. O objetivo do presente estudo foi avaliar os efeitos da PDT sobre a viabilidade de Enterococcus faecalis, utilizando azul de metileno (MB) e verde malaquita (MG) como fotosensibilizantes. Solucoes contendo E. faecalis (ATCC 29212) foram preparadas e colhidas por centrifugacao, para se obter suspensoes de celulas que foram misturadas com o MB e MG. As amostras foram irradiadas individualmente pelo diodo laser a uma distancia de 1 milimetro por 30, 60 ou 120 segundos. Unidades formadoras de colonias (UFC) foram determinados para cada tratamento. PDT por 60 e 120 segundos com MG reduz significativamente a viabilidade de E. faecalis. Resultados semelhantes foram observados quando MB foi utilizado como fotosensibilizante. PDT utilizando MB ou MG tem efeito antibacteriano contra E. faecalis, mostrando o potencial de ser usada como um adjuvante do processo antimicrobiana em endodontia.

Photodynamic therapy (PDT) has been proven to be effective in disinfecting root canals. The aim of this present study was to evaluate the effects of PDT on the viability of Enterococcus faecalis using methylene blue (MB) and malachite green (MG) as photosensitizers. Solutions containing E. faecalis (ATCC 29212) were prepared and harvested by centrifugation to obtain cell suspensions, which were mixed with MB and MG. Samples were individually irradiated by the diode laser at a distance of 1mm for 30, 60, or 120 seconds. Colonyforming units (CFU) were determined for each treatment. PDT for 60 and 120 seconds with MG reduced E. faecalis viability significantly. Similar results were obtained when MB was used as photosensitizer. PDT using MB and MG have antibacterial effect against E. faecalis, showing potential to be used as an adjunctive antimicrobial procedure in endodontic therapy.

AIM: To evaluate the cytotoxicity of several storage media (coconut water, whole milk, isotonic solution, Hank´s Balanced Salt Solution and tap water) using a multiparametric cytotoxicity analysis employing 3T3 cells. METHODS: Plates containing confluent 3T3 fibroblasts were exposed to the various media for 24h, at 37°C with 5% CO2, and cell viability was evaluated by a multiparametric assay assessing sequentially, on the same cells, mitochondrial activity (XTT), membrane integrity (neutral red test), and total cell density (crystal violet dye exclusion test). Results from each test were compared by one-way analysis of variance (ANOVA). RESULTS: Statistical analysis showed that whole milk and HBSS were the most effective media in maintaining cell viability at all tested times (p<0.05). Isotonic and tap water showed the highest cytotoxicity effects. CONCLUSIONS: This study shows that whole milk and HBSS are more efficient in maintaining the viability of 3T3 fibroblasts as demonstrated by three different cell viability tests.

OBJETIVO: Comparar a resposta do tecido subcutâneo de ratos frente a dentina contaminada com Enterococcus faecalis associado ao soro fisiológico 0.9% , hipoclorito de sódio 5.25% (NaOCl) ou clorexidina gel 2% (CHX). METODOLOGIA: Foi realizada a contaminação de dentina em pó com E. faecalis. As substâncias testadas foram misturadas com a dentina contaminada e inseridas em tubos de polietileno. Dez ratos Wistar tiveram os dorsos divididos em quatro quadrantes e cada quadrante recebeu um tubo com cada uma das misturas testadas. Um tubo vazio foi utilizado como controle. Os ratos foram distribuídos em dois grupos para avaliação no período de 24 e 72 horas. Os tecidos foram processados histologicamente e as reações teciduais foram avaliadas sobre microscopia de luz. RESULTADOS: Os grupos de NaOCl 5.25% promoveram maiores reações inflamatória após 24 e 72 horas. Quando comparado com os grupos de CHX 2%, os grupos de soro fisiológico 0.9% mostraram inflamação moderada após 24 horas e severa após 72 horas. CONCLUSÃO: Os resultados indicaram que o grupo de NaOCl 5.25% apresentou maior reação inflamatória aos tecidos subcutâneos de rato e que o grupo de CHX 2% apresentou menor reação inflamatória.

PURPOSE: To compare rat subcutaneous connective tissue reaction to dentine contaminated with Enterococcus faecalis associated with 0.9% sterile saline, 5.25% sodium hypochlorite (NaOCl) and 2% chlorhexidine gel (CHX). METHODS: Dentine was crushed into powder and inoculated with E. faecalis. Tested substances were mixed with contaminated dentine and placed in polyethylene tubes. Ten male Wistar rats had their backs divided into four quadrants that received an implant containing one of the tested substances. An empty tube was used as a control. Five rats were randomly distributed for evaluation at time intervals of 24 hours and 72 hours. Tissue samples were histologically processed. Tissue reactions to experimental groups were evaluated under optical microscopes. RESULTS: Groups of 5.25% NaOCl induced greater inflammatory response after 24 hours and 72 hours. Compared to groups of 2% CHX, the groups of 0.9% sterile saline showed milder inflammatory reactions after 24 hours and more severe after 72 hours. CONCLUSION: The results indicate that 5.25% NaOCl group showed a higher inflammatory reaction to rat subcutaneous connective tissue and the 2% chlorhexidine group showed the least reaction.

The surface of gutta-percha cones was evaluated after using five different cutting methods, including a new TipSnip device . The gutta-percha cones were cut off using: 1) TipSnip, 2) a single cut with a scalpel blade using a gauge, 3) two cuts with a scalpel blade using a gauge, 4) a razor blade against a glass slab or 5) scissors. Samples were examined under stereomicroscopy and observed by three highly qualified evaluators. The Kappa coefficient with a 95% confidence interval was used and all scores were tabulated and analyzed statistically using a nonparametric Kruskal-Wallis test with a 5% significance level. Cutting with scissors produced significant irregularities in the cone surface, providing the worst result. TipSnip, two cuts with scalpel blade, and cut with a razor against a glass slab provided the best results. A regular surface on the tips of gutta-percha cones improves apical fit, and may be achieved by means of different cutting methods.

Fue evaluada la superficie de conos de gutapercha después de ser calibrados con cinco diferentes métodos de corte, incluyendo el nuevo dispositivo TipSnip. Los conos de gutapercha fueron cortados con TipSnip, con un corte con hoja de bisturí en regla calibrada, con corte de ida y vuelta con hoja de bisturí en regla calibrada, con hoja de afeitar sobre una platina de vidrio, o con tijeras. Las muestras fueron observadas bajo microscopía estereoscópica y examinadas por tres evaluadores altamente calificados y previamente calibrados utilizado el coeficiente Kappa con intervalo de confianza del 95%; todos los resultados fueron tabulados y analizados estadísticamente mediante el test no paramétrico de Kruskal-Wallis con un nivel de significancia del 5%. El corte con tijeras produjo significativas irregularidades en la superficie del cono, siendo el grupo con peores resultados. El corte con TipSnip, el corte de ida y vuelta con hoja de bisturí, y la hoja de afeitar obtuvieron los mejores resultados. Una superficie regular en la punta de los conos de gutapercha mejora la adaptación apical, y esto puede conseguirse por medio de diferentes métodos de corte.

The aim of this study was to evaluate the remaining dentine/cementum thickness using Gates-Glidden burs in serial and crown-down sequences and to observe which of the two sequences is the safest for preparing mesial roots of molars. Thirty-six left and right human mandibular first molars were selected. Standard access cavities were made and initially explored with Flexofiles sizes 10 and 15 until the tip was visible at the apex. The teeth were embedded in a muffle specially developed for this study using a PVC tube with two parallel metal rods in its lid. Each tooth-block was sectioned 3 mm apically to the furcation using a low-speed saw with a diamond disc. The tooth-block was examined under a microscope and an initial image was captured by a digital video system with 8 X and 12 X magnifications. Finally, the tooth-blocks were reassembled in the muffle so that the canals could be instrumented. After instrumentation the area of each mesial canal as well as the smallest distance to the root furcation were measured again. The mesio-buccal canals (crown-down order) and the mesio-lingual canals (serial sequence) presented an average area of 0.46 ± 0.16 mm² and 0.88 ± 0.27 mm² (P < 0.01), respectively. The mean values of the smallest distance to the furcation for the mesio-buccal and mesio-lingual canals were 0.66 ± 0.19 mm and 0.39 ± 0.13 mm (P < 0.01), respectively. The remaining dentine/cementum thickness using Gates-Glidden burs was greater in the crown-down sequence than in the serial sequence.

O objetivo deste estudo foi avaliar a influência do uso do microscópio cirúrgico na localização do canal mesiopalatino (MP) em primeiros molares superiores humanos permanentes extraídos. Cento e oito primeiros molares superiores permanentes foram selecionados aleatoriamente e montados em um manequim dental. Uma cavidade de acesso convencional foi realizada e uma tentativa de se localizar o canal mesiopalatino foi feita, utilizando-se somente uma sonda exploradora afiada, um odontoscópio e uma lima tipo K tamanho 10. Quando não localizado o referido canal, os dentes foram então avaliados com auxílio de um microscópio cirúrgico (MC). As raízes mésio-vestibulares de todos os dentes nos quais o canal MP não foi localizado foram então seccionadas transversalmente e exploradas com auxílio do MC, com um aumento de 25 X. Os canais MP foram detectados em 58 dentes em que se usaram somente uma sonda exploradora afiada, um odontoscópio e uma lima tipo K tamanho 10. Nos 50 dentes restantes, 37 canais MP foram localizados com o auxílio do MC e 3 canais MP foram localizados após a secção das raízes. Em 10 dentes os canais MP não foram localizados. Os resultados deste estudo mostraram uma alta incidência do canal MP na raiz mésio-vestibular do primeiro molar superior permanente (90.7%) e demonstraram que o uso adjunto do MC aumentou a capacidade do operador em localizar o canal MP.

The aim of this study was to evaluate the influence of using the surgical operating microscope (SOM) for detection of the mesiolingual (ML) canal orifice in extracted first maxillary permanent molars. One hundred and eight human first maxillary permanent molars were randomly selected and mounted onto a dental chair mannequin. Conventional access cavity was prepared and an attempt was made to locate the mesiolingual canal orifice using only a sharp explorer, a mirror and a #10 K-file. A mesiolingual canal orifice was either located or not located. If not located, the teeth were then evaluated by using a surgical operating microscope (SOM). The mesiobuccal roots of all teeth where the ML canal orifice had not been located were sectioned in an axial plane and the sections were explored with an adjunctive use of the SOM at a 25 X magnification. ML canal orifices were detected in 58 teeth using only a sharp explorer, a mirror and #10 K-file. In the remaining 50 teeth, 37 ML canal orifices were located by using the SOM and 3 ML canal orifices were located after root sectioning. In 10 teeth, the ML canal orifices were not found. The results of this study showed a high incidence of a ML canal in the mesiobuccal roots of the first maxillary molars (90.7%) and demonstrated that the adjunctive use of the SOM increased the ability of the dental clinician to locate the ML canal orifice.

O objetivo deste estudo foi avaliar a qualidade do selamento obtido por 3 técnicas de obturação em canais ovais, através de um modelo de infiltração bacteriano. Setenta incisivos inferiores com canais ovais foram selecionados após radiografias bucolinguais e mésio-distais, e divididos em 3 grupos. Após a instrumentação, os dentes foram obturados respectivamente pela condensação lateral (G1), condensação vertical da guta-percha aquecida (G2) e pelo Thermafil (G3). Cinco canais radiculares que não foram obturados serviram como grupo controle positivo, e cinco com as coroas intactas serviram como grupo controle negativo. Todos os dentes foram montados em um aparato de 2 câmaras e expostos à saliva humana. O número de dias necessário à total contaminação do canal radicular foi verificado, através da observação do turvamento do BHI, por um período de 100 dias. Não apresentaram contaminação ao término do estudo 84,21% das amostras do grupo da condensação lateral (G1); 84,21% das amostras do grupo da condensação vertical da guta-percha aquecida (G2); e 89,47% das amostras do grupo do Thermafil. Não houve diferença estatisticamente significativa entre as 3 técnicas. A qualidade do selamento apical nas 3 técnicas testadas foi similar.

The aim of this study was to evaluate the sealing ability of 3 obturation techniques in oval canals using a bacterial leakage model. Seventy mandibular incisors with oval canals were selected after buccolingual and mesiodistal radiographs, and divided into three groups. After instrumentation, the canals were obturated respectively by lateral condensation (G1), warm vertical condensation (G2) and Thermafil (G3). Five root canals were not obturated and served as positive controls; five teeth with intact crowns served as negative controls. All teeth were mounted on a 2 chamber apparatus and then exposed to human saliva. The number of days required for the entire contamination of the root canals was recorded, observing the turbidity of the BHI broth, for a period of 100 days. 84.21% of the samples from the lateral condensation group (G1); 84.21% of the samples from the warm vertical condensation group (G2); and 89.47% of the samples from the Thermafil System group (G3) showed no contamination at the end of the study. No statistical significant difference was found among the three techniques. The quality of the apical seal in the three techniques tested was similar.

O objetivo deste estudo foi realizar uma análise quantitativa da espessura da linha de cimento endodôntico formada por três técnicas de obturação. Trinta incisivos centrais superiores humanos foram selecionados e acessados de modo convencional. Uma lima nº 15 K-Flexofile foi usada para a verificação da patência foraminal e para determinação do comprimento de trabalho, que foi estabelecido a 1 mm aquém do forame apical. Os canais foram preparados até a lima nº 45. Hipoclorito de sódio a 5,25% foi usado durante toda a instrumentação. Os dentes foram divididos em 3 grupos e obturados pelos seguintes critérios: G1 - condensação lateral; G2 - compressão hidraúlica e G3 - onda de condensação. Os dentes foram seccionados e analisados nos terços cervical, médio e apical. A espessura do filme de cimento foi determinada por um processo semi-automático de análise e processamento digital de imagens realizado no software KS 400. O tratamento estatístico foi realizado com teste de Wilcox, que revelou diferenças significantes entre G3 e G1 e entre G3 e G2, sendo p £ 0,05. Não houve diferenças estatisticamente significantes entre G1 e G2. De um modo geral, a compressão hidraúlica (G2) e condensação lateral (G1) revelaram uma maior espessura do filme de cimento. A menor espessura do filme de cimento obtida pela técnica de onda de condensação tende a melhorar a performance clínica dessa técnica em relação às outras testadas.

The aim of this study was to obtain a quantitative analysis of the film thickness of a root canal sealer formed after filling by three different techniques. Thirty human maxillary incisors were selected and access cavities were prepared using high-speed diamond stones and water spray. A size #15 K-Flexofile was introduced in the canal of each specimen until it was seen just at the apical foramen. The working length was determined to be 1 mm short of that position and the canals were prepared to an apical size of #45 K-Flexofile. Copious irrigation with 5.25% NaOCl (sodium hypochlorite) was used during and after instrumentation. The samples were divided into three groups and obturated as follows: G1 - lateral condensation, G2 - lateral condensation with an accessory cone, and G3 - continuous wave of condensation. The samples were evaluated in the cervical, middle and apical thirds. The film thickness of the root canal sealer was measured through a microscopic evaluation. Statistical analysis was obtained using the Wilcox test. Statistical analysis showed significant differences between G3 and G1, G3 and G2 (p < 0.05). In general, the lowest film thickness was observed in the continuous wave of condensation (G3). Lateral condensation with an accessory cone (G2) and lateral condensation (G1) demonstrated poorer results in this study, showing a higher film thickness. The small film thickness of the sealer obtained by the continuous wave of condensation technique may increase the clinical performance of this technique.

Este estudo foi desenvolvido para avaliar a capacidade de penetração de diferentes cimentos endodônticos (Endo Fill, Sealapex, AH Plus e Pulp Canal Sealer) nos túbulos dentinários em dentes devidamente modelados e obturados. Foram utilizados 72 incisivos centrais superiores, os quais foram instrumentados no sentido coroa-ápice pela técnica de forças balanceadas. O comprimento de trabalho foi estabelecido a 1 mm do ápice radicular. Durante a limpeza e modelagem, todos os dentes foram irrigados com 10 ml de hipoclorito de sódio a 5,25%. Os dentes foram divididos em 4 grupos, sendo 1 para cada tipo de cimento. Estes grupos foram então subdivididos em função do uso ou não de EDTA a 17% previamente à obturação dos canais radiculares, para a remoção da lama dentinária. Todos os dentes foram obturados pela técnica da onda de condensação com cone médio calibrado. Após obturação, as raízes foram seccionadas no sentido mésio-distal e foi escolhida a secção de melhor qualidade visual. Estas foram então analisadas em microscopia eletrônica de varredura (MEV), sendo o foco de observação sempre a interface dentina/material obturador. Após obtenção das imagens, mensurou-se os prolongamentos dos cimentos para o interior dos túbulos dentinários. O cimento de Rickert (Pulp Canal Sealer) apresentou a maior capacidade de penetração nos túbulos dentinários, sendo os piores resultados apresentados pelo grupo em que se utilizou o Sealapex. Os resultados foram avaliados estatisticamente pelo teste de Spearman, o qual mostrou diferença estatisticamente significante (p <=0,01) entre os grupos em que o EDTA foi utilizado.

The purpose of this study was to evaluate the capacity of penetration of four endodontic sealers (Endo Fill, Sealapex, AH Plus and Pulp Canal Sealer) into dentinal tubules. Seventy-two extracted human maxillary anterior teeth were utilized in this study. The teeth were cleaned and shaped by means of the balanced-forces technique. The work length was established at 1 mm beyond the apex. Copious irrigation with 10 ml of 5.25% sodium hypochlorite was carried out. The teeth were divided in 8 groups - 4 had the smear layer maintained, and 4 had it removed. The smear layer was removed with a commercial solution of 17% EDTA, and the root canal system was flushed for 3 min. Finally, the roots were irrigated with 3 ml of 5.25% sodium hypochlorite. All teeth were sealed by means of the technique of the condensation wave with a medium nonstandardized cone. After filling, the roots were grooved, longitudinally split and examined under a scanning electron microscope (SEM). The focus of observation was the interface between the dentin and the sealing material. The Rickert sealer (Pulp Canal) presented the maximum penetration depths into the dentinal tubules, and Sealapex, the minimum. The Spearman test was used to determine whether there were significant differences between the groups. The removal of smear layer allowed significant penetration of the sealers (p <= 0.01).