Estudo ex vivo da elevação do pH em superfície radicular externa após agitação ultrassônica de diferentes pastas de hidróxido de cálcio / Assessment of pH increase in the external root surface after ultrasonic agitation of different calcium hydroxide pastes: Ex vivo study

Objetivo: O presente estudo teve por objetivo avaliar, ex vivo, a capacidade de elevação do pH da superfície radicular externa de diferentes pastas de hidróxido de cálcio (HC) utilizadas como medicação intracanal, além da influência da ativação ultrassônica (AUS) durante aplicação no interior do canal radicular. Métodos: Foram utilizados 100 incisivos humanos superiores unirradiculares, que tiveram os canais radiculares modelados e divididos aleatoriamente em seis grupos experimentais (n=15), de acordo com a pasta de HC, tendo como variáveis as medicações utilizadas e a ativação da pasta com AUS no momento da aplicação, além de um grupo controle (n=10): Pasta Calen; HC+clorexidina 2% gel (CX2%); e HC + água destilada. Os dentes foram mantidos imersos em água deionizada e as medidas do pH, verificadas nos períodos de 7, 14, 21 e 28 dias, com auxílio de pHmetro. Resultados: De acordo com os dados obtidos, verificou-se elevação do pH nos períodos de 7 e 14 dias em todos os grupos. Apenas os grupos em que foi utilizada a associação do HC com CX2% apresentou evolução com aumento significativo do pH ao longo dos períodos analisados (p<0,05). A ativação das pastas com AUS proporcionou incremento significativo dos valores de pH (p<0,05). Conclusão: De acordo com a metodologia empregada, pode-se concluir que todas as pastas utilizadas promovem elevação do pH no tecido dentinário, e a ativação das pastas com AUS influencia significativamente na elevação do pH no tecido dentinário (AU).

Objective: The aim of the present study was to evaluate, ex-vivo, the pH elevation capacity on the external root surface of different calcium hydroxide (HC) pastes, utilized as intracanal medication, it was also evaluated the influence of the ultrasonic activation at the application within the root canal. Methods: 100 human single root superior incisors were used, which had their root canals shaped and randomly divided into 6 experimental groups (n=15) according to the following HC pastes: Calen; HC + Chlorhex- idine 2% gel (CX2%); HC + distilled water, utilizing the medications and the ultrasonic activation of the paste at the time of the application as variables and 1 control group (n=10). The teeth were kept immersed in deionized water and the pH parameters were verified in 7, 14, 21 and 28 days with a pH measurement machine. Results: According to the data obtained, pH was elevated in the first week in all groups. Only the groups which the association of HC with CX2% was made, did show a significant increase in the pH level over the analyzed periods (p < 0,05). The activation of the pastes with US provided a significant increase in pH values (p < 0,05). Conclusion: According to the methodology used, we can conclude that all the HC pastes used, promote pH elevation in dentin tissue. And the acti- vation of the pastes with US significantly influences the pH increase in dentin tissue

Cyclic fatigue resistance of different continuous rotation and reciprocating endodontic systems.

Objective: The objective of this study is to compare the cyclic fatigue resistance of nine types of endodontic instruments of nickel–titanium. Materials and Methods: Five files of 25 mm of length of each group: Reciproc (RC) R25; WaveOne (WO) Primary; Unicone (UC) L25 25/0.06; K3XF 25/0.06; ProTaper Universal F2 (PTF2); ProTaper Next X2 (PTX2); Mtwo 25/0.06; BioRaCe 25/0.06; One Shape L25 25/0.06 were subjected to a cyclic fatigue resistance test on a mechanical apparatus. The mean fracture time was analyzed statistically by one-way analysis of variance and Tukey’s honest significant difference post hoc test, with significance set at P < 0.05. Conclusion: It was observed that the groups PTX2, RC, R25, UC L25 25/0.06, and WO Primary presented greater cyclic fracture resistance than the other groups (P < 0.001).

Comparative evaluation of push-out bond strength of a MTA-based root canal sealer

AIM: To evaluate the bond strength to root dentin of three root canal sealers: a mineral trioxide aggregate (MTA)-based sealer (MTA Fillapex(r)), an epoxy resin-based sealer (AH Plus(r)), and a zinc oxide eugenol-based sealer (EndoFill(r)). METHODS: Thirty extracted single-root human teeth of similar sizes and circular canals were prepared using #3 and #2 Gates Glidden drills in the cervical portion of the canal and K3(r) rotary instruments to a size #25/0.06 to working length. Irrigation with 0.5 mL 2% chlorhexidine gel was used before and 1 mL saline after each instrument.The smear layer was removed with 3 mL 17% EDTA for 3 min. The samples were sectioned horizontally into eight 1±0.1 mm-thick serial slices and then the push-out test was carried out. Two-way analysis of variance (ANOVA) and the post-hoc Tukey test were used for the analysis of the data with a significance level of 5%. RESULTS: AH Plus presented significantly higher bond strengths (p<0.05) than the other sealers, while MTA Fillapex showed the lowest bond strengths (p<0.05). CONCLUSIONS: The present study concluded that EndoFill(r) sealer and MTA FillApex(r) core combination were not superior to AH Plus(r) sealer and gutta-percha core combination...

Preliminary investigation to achieve patency of MB2 canal in maxillary molars

Aim: To establish a preliminary investigation about the possibility to achieve patency of second mesiobuccal canal (MB2) in mesiobuccal roots of maxillary molars. Methods: Three hundred and five first maxillary molars were examined with direct vision and with magnification. The root canal configurations were classified according to the possibility to achieve patency in MB2 canals. Clearing technique was also performed to illustrate root canal anatomy and verify the presence of extra canals not identified with magnification. Results: The prevalence of MB2 canals detected only with direct vision was 53.4% and the use of the surgical operating microscope increased rate detection to 90.7%. The clearing technique revealed the presence of MB2 canal in 12 more teeth (94.7%). In 49.1% of the localized MB2 canals, it was not possible to achieve patency. Conclusions: The findings of the presented study revealed that it was only possible to achieve patency in 50.9% of the MB2 canals, showing that achieve patency in the MB2 canal is much more challenging than locating them.

In vitro penetration of two cements into artificially created lateral canals / Análise in vitro da obturação de canais laterais simulados utilizando dois tipos de cimentos

Objective: The aim of this study was to assess the penetration of two obturation materials, Guta-percha (Konne Ind. e Com. Ltda., Belo Horizonte, Brazil) / Pulp Canal Sealer (Kerr Sybron, Romulus, USA) and Resilon (Resilon Research LLC, Madison, CT, USA) / Epiphany (Pentron Clinical Technologies, Wallingford, CT, USA), into artificially created lateral canals. Methods: Twenty upper, single-rooted human teeth with full or partial crown, straight root and radiograph suggesting one root canal were selected. Six lateral canals were created on each root, two on each third. The teeth were then divided randomly into 2 groups of 10 teeth each. The continuous wave of condensation technique was used to obturate all canals. After obturation, the roots were sectioned cross-sectionally into 3 segments with a diamond disc to expose the lateral canals. The segments were fixed in a fast curing epoxy resin and micrographs of the lateral canals magnified 20 times were taken. The software Carnoy 2.0 was then used to measure obturation material penetration into each lateral canal. The data were treated by the non-parametric Kruskal-Wallis test. Results: The extent of the lateral canals penetrated by the two obturation materials did not differ significantly in any of the root thirds (p>0.05). Conclusion: Both obturation materials, Guta-percha (Konne Ind. e Com. Ltda., Belo Horizonte, Brazil) / Pulp Canal Sealer (Kerr Sybron, Romulus, USA) and Resilon (Resilon Research LLC, Madison, CT, USA) / Epiphany (Pentron Clinical Technologies, Wallingford, CT, USA), presented good penetration, which did not differ significantly.

Objetivo: Avaliar a capacidade de selamento de canais laterais simulados frente a dois sistemas obturadores: Guta-percha (Konne Ind. e Com. Ltda., Belo Horizonte, Brasil) e cimento Pulp Canal Sealer (Kerr Sybron, Romulus, USA) e Resilon (Resilon Research LLC, Madison, CT, USA) com Epiphany (Pentron Clinical Technologies, Wallingford, CT, USA). Métodos: Foram selecionados 20 dentes humanos unirradiculares superiores, com coroas totais ou parcialmente íntegras, raízes retas e imagem radiográfica sugestiva de um canal. Foram confeccionados seis canais laterais, com a utilização de uma broca Long Neck ½ (Dentsply-Maillefer, Ballaigues, Suíça), em cada espécime, sendo igualmente distribuído nos 3 terços radiculares. Posteriormente, os dentes foram divididos aleatoriamente em 2 grupos de 10 dentes. A técnica de obturação utilizada foi a Onda Contínua de Condensação. Após as obturações, as raízes foram seccionadas transversalmente com um disco de diamante em 3 segmentos, que possibilitou a visualização dos canais laterais. Os segmentos foram incluídos em uma resina epóxica de presa rápida. As imagens dos terços radiculares inseridos em resina epóxica foram capturadas em lupa estereomicroscópica, com aumento de 20 vezes. Foram realizadas medições lineares das obturações em cada um dos canais dos diferentes segmentos dos dentes de cada grupo através do programa Carnoy 2.0. Os dados foram submetidos à análise estatística utilizando o teste não paramétrico de Kruskall-Wallis. Resultados: A análise dos resultados demonstrou não haver diferença estatística no escoamento entre os materiais obturadores e seus terços apicais, médios e cervicais (p > 0,05). Conclusão: Concluiu-se que os dois materiais obturadores, apresentaram um bom escoamento nos canais laterais, não havendo diferença estatística entre eles.

Evaluation of the dentin remaining after flaring using Gates Glidden drills and Protaper rotary files

INTRODUCTION: The application of rotary instruments for root canal preparation requires a safe, not harming procedure to the root structure remaining. OBJECTIVES: The purpose of this study was to analyze the root thickness in 28 mesial canals of lower permanent first molars before and after flaring using two rotary instruments: Gates-Glidden drills and ProTaper rotary files. MATERIAL AND METHODS: Teeth were embedded into a muffle system. Samples were obtained by cutting 2mm below the furcation. The images were captured by a digital video system (8X and 12X magnification). For image analysis and processing, Pro-Image Plus 4.1 software was used. Each image captured by the computer was gauged, eliminating any possible distortion. Gates-Glidden drills were used in decreasing order of size (GG#4, GG#3, GG#2). ProTaper was used according to the manufacturer's recommendations, with hand-piece powered by an electric motor with low torque. 5.25 percent sodium hypochlorite was utilized as irrigant. RESULTS: The average thickness between the canal and furcation before and after use of rotary instruments were: 0.857 mm and 0.561 mm for Gates-Glidden drills, and 0.858 mm and 0.486 mm for ProTaper, respectively. No statistical differences were found in the root thickness of specimens shaped with ProTaper rotary files and Gates Glidden drills. CONCLUSION: The use of Gates-Glidden drills is as safe as ProTaper rotary files with respect to danger of perforation on the distal side of the mesial roots of lower molars.

Avaliação in vivo da dor pós-operatória em dentes vitais após o alargamento do forame apical / In vivo evaluation of post operative pain in vital pulps after the foramen enlargement

Objetivo: O objetivo do presente trabalho foi avaliar a dor pós-operatória em dentes vitais uni ou birradicularessubmetidos ou não ao alargamento foraminal até a lima # 30. Métodos: Quarenta dentes foram selecionados e divididos randomicamente em dois grupos. No Grupo I (experimental) foi preconizada ampliação foraminal até a lima # 30 e comprimento de trabalho 1 a2 mm aquém do forame. No Grupo II (de controle) foi preconizado limite de trabalho de 1 a 2 mm aquém do ápice e manutenção do remanescente pulpar. Todos os procedimentos foram realizados pelo mesmo operador. A vitalidade foi analisada com base em aspectos clínicos e radiográficos. Todos os dentes foram tratados em sessão única e o localizador apical Root ZX® foi utilizado para a determinação do comprimento de trabalho, conjuntamente com a comprovação radiográfica. A dor foi avaliada por um período de 24 e 48h. Resultados e Conclusão: Com base nos resultados relatados pelos pacientes, não foi observada diferença estatística entreos dois grupos, ou seja, o alargamento do forame apical não aumentou a incidência de dor

Ex vivo evaluation of coronal and apical microbial leakage of root canal - Filled with gutta-percha or Resilon/Epiphany root canal filling material.

Objective: This ex vivo study compared coronal and apical microleakage of root canals filled with Resilon/Epiphany (RE) or gutta-percha/Grossman sealer (GP), using either lateral condensation (LC) or System B (SB) technique. Materials and Methods: Specimens in eight experimental groups were obturated using the following materials and techniques: Groups 1 and 3 - GP and LC; groups 2 and 4 - GP and SB; groups 5 and 7 - RE and LC; groups 6 and 8 - RE and SB. Apical and coronal leakages were tested using bacterial methods. For coronal analysis, the number of days required for complete contamination of the root canals was recorded according to observation of the brain heart infusion broth turbidity for 15 weeks. For apical analysis, the teeth were cleaved and the leakage was measured at 30 days. Data were collected for each sample and analyzed statistically with the Chi-square and ANOVA tests. Results: Leakage was found in all groups. The difference between filling materials, obturation techniques, and median time of leakage was not statistically significant for coronal ( P=0.847) and apical ( P=0.5789) leakages. Conclusion: There were no differences between the different filling materials (gutta-percha/Grossman sealer and Resilon/Epiphany) and obturation techniques (lateral condensation and system B technique) in coronal or apical leakages.

Coronal leakage of four intracanal medications after exposure to human saliva in the presence of a temporary filling material.

Aim: To determine the time required for the recontamination of root canals medicated with four different materials. Materials and Methods: A total of 60 intact, caries-free, human single-rooted teeth with straight roots were selected for this study. After chemo-mechanical preparation they must be changed in the specimens into seven groups: 10 teeth medicated with calcium hydroxide (Ca(OH) 2) + Camphorated paramonochlorophanol (CPMC) (G.1); 10 medicated with 2.5% Sodium hypochlorite (NaOCL) (G.2); 10 medicated with 2% Chlorhexidine gluconate (CHX) in gel (G.3); 10 medicated with 2% CHX in gel + Ca(OH) 2 (G.4); 10 without intracanal medicament and sealed with a coronal temporary filling (G.5). Five teeth were without intracanal medicament and coronally unsealed, used as the positive control group (PC) (G.6) and 5 teeth with intact crowns used as the negative control group (NC) (G.7). Glass vials with rubber stoppers were adjusted for use. The medicaments were prepared and injected into the root canals using sterile plastic syringes. An apparatus was used to evaluate for 30 days leakage. The chamber was filled with 3 ml of human saliva and Brain Heart Infusion (BHI) broth, incubated at 37°C and checked daily for the appearance of turbidity in the BHI broth. Results: Recontamination was detected after an average time of 2.6 days in group 2, 15.9 days in group 3, 30 days in group 1, 27.6 days in group 4, 2.9 days in group 5, 1 day in the positive control, and there was no contamination in the negative control group. Conclusion : The NaOCl group showed the highest worst average of recontamination; on the other hand, high averages were also shown by Ca(OH) 2 + CPMC and Ca(OH) 2 + 2% CHX in gel.

Evaluation of the risk of a stripping perforation with gates-glidden drills: serial versus crown-down sequences

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.

Cleaning ability of chlorhexidine gel and sodium hypochlorite associated or not with EDTA as root canal irrigants: a scanning electron microscopy study

The aim of this study was to evaluate the cleaning efficacy of 2 percent chlorhexidine gluconate gel (CHX) compared to 2.5 percent sodium hypochlorite solution (NaOCl) associated or not with 17 percent EDTA used as irrigants during the biomechanical preparation. Fifty freshly extracted single-rooted human teeth with complete apex formation were randomly divided into five groups: G1 - sterile saline, G2 - 2.5 percent NaOCl, G3 - 2 percent CHX, G4 - 2.5 percent NaOCl + EDTA and G5 - 2 percent CHX + EDTA. The specimens of G1 were subdivided into two control groups. The teeth were decoronated and the coronal and middle root thirds were prepared with Gates-Glidden burs, and the apical third was reserved to manual instrumentation. All procedures were performed by a single operator. In all groups, 2 mL of irrigant was delivered between each file change. The teeth were sectioned and prepared for analyses under scanning electron microscopy (SEM). SEM micrographs were graded according to a score scale by two examiners. Data were analyzed statistically by Kruskal-Wallis and Dunn tests at 1 percent significance level. The best results were obtained in the groups in which the irrigant was used followed by the chelating agent. No statistically significant difference was observed among G4, G5 and the positive control group (p<0.01). The groups G2 and G3 were significantly different from the others, presenting the worst cleaning capacity. In conclusion, the use of the chelating agent is necessary to obtain clean canal walls, with open tubules and no heavy debris. The use of 2 percent chlorhexidine gluconate gel alone is not able to remove the smear layer.

Brazilian gutta-percha points. Part II: thermal properties

This study was undertaken to explore the effect of heating on gutta-percha, analyzing the occurrence of endothermic peaks corresponding to the transformation that occurs in the crystalline structure of the polymer during thermal manipulation. This study also seeked to determine the temperature at which these peaks occur, causing a transformation from the beta- to the alpha-form, and from the alpha- to the amorphous phase. Eight nonstandardized gutta-percha points commercially available in Brazil (Konne, Tanari, Endopoint, Odous, Dentsply 0.04, Dentsply 0.06, Dentsply TP, Dentsply FM) and pure gutta-percha (control) were analysed using differential scanning calorimetry (DSC) and thermogravimetry analysis (TGA). The transition temperatures were determined and analysed. With the exception of Dentsply 0.04 and Dentsply 0.06, the majority of the products showed thermal behaviour typical of beta-gutta-percha, with two endothermic peaks, exhibiting two crystalline transformations upon heating from ambient temperature to 130°. Upon cooling and reheating, few samples presented two endothermic peaks. It was concluded that heating dental gutta-percha to 130°C causes changes to its chemical structure which permanently alter its physical properties.

Este estudo teve como objetivo analisar, através da Calorimetria Diferencial de Varredura (DSC) e Análise Termogravimétrica (TGA), os efeitos do aquecimento sobre o polímero guta-percha, bem como explorar a ocorrência de picos endotérmicos, os quais correspondem às transformações cristalinas do polímero guta-percha, o que é traduzido em transições de fases (fase beta para alfa e fase alfa para amorfa). Foram utilizadas 8 marcas comerciais de cones de guta-percha não-estandardizados disponíveis no mercado brasileiro (Konne, Tanari, Endopoint, Odous, Dentsply 0.04, Dentsply 0.06, Dentsply TP, Dentsply FM), além da guta-percha pura (controle). As temperaturas de transição foram determinadas e analisadas. Com exceção das amostras Dentsply 0.04 e Dentsply 0.06, todas as demais apresentaram duas transformações cristalinas de fase quando submetidas ao aquecimento da temperatura ambiente até 130°C, comportamento típico de guta-percha em fase beta. Ao serem resfriadas e reaquecidas, poucas amostras apresentaram dois picos endotérmicos. É possível concluir que o aquecimento a 130°C causa danos na estrutura química do polímero guta-percha, o qual altera de forma definitiva suas propriedades físicas.

In vitro evaluation of the effectiveness of the chemomechanical preparation against Enterococcus faecalis after single- or multiple-visit root canal treatment

The purpose was to assess the elimination of Enterococcus faecalis in vitro in human mandibular premolars after chemomechanical preparation with or without the use of a calcium hydroxide dressing. After 60 days of contamination with E. faecalis, the root canals were prepared using the Crown-Down technique combined with 2 percent chlorhexidine gel irrigation. Then, the specimens were divided into two experimental groups, treated in a single visit or in multiple visits, and two control groups. The multiple-visit group received a dressing with calcium hydroxide for 14 days (CalenTM) and the single-visit group did not receive any medication. In the two control groups, the canals were filled with BHI after chemomechanical preparation with 2 percent chlorhexidine gel or distilled water. Microbial samples were taken from the root canals for colony forming unit count for each phase of the treatment using sterile paper points inside the root canal lumen. Data were ranked and analyzed by the Kruskal-Wallis statistical test. The residual microbial colonies were then assessed. The results showed that chemomechanical preparation using 2 percent chlorhexidine gel with no intra-canal dressing reduced by 100 percent the E. faecalis contamination of the root canal lumen. The calcium-hydroxide group that received the 14-day intra-canal dressing allowed a small number of bacteria to grow between visits, but without statistical differences between groups.

Objetivou-se avaliar in vitro a eliminação do Enterococcus faecalis em pré-molares inferiores humanos após o preparo químico-mecânico seguido ou não de curativo de hidróxido de cálcio. Após 60 dias de contaminação com E. faecalis os canais radiculares foram preparados utilizando-se a técnica coroa-ápice associada à irrigação com clorexidina em gel a 2 por cento. Posteriormente os espécimes foram divididos em dois grupos experimentais, tratados em uma ou duas sessões, e dois grupos controles. O grupo tratado em duas sessões recebeu medicação intracanal de hidróxido de cálcio por 14 dias (CalenTM) e o grupo de sessão única não recebeu medicação. Nos dois grupos controles, após o preparo químico-mecânico com clorexidina em gel a 2 por cento ou água destilada, os canais foram preenchidos com BHI. Amostras microbiológicas foram coletadas dos canais radiculares e contadas por meio de unidades formadoras de colônia em cada fase do tratamento utilizando-se ponta de papel dentro da luz do canal. Os dados foram analisados estatisticamente pelo teste de Kruskal-Wallis. As colônias bacterianas residuais foram então mensuradas. A utilização da clorexidina em gel a 2 por cento sem emprego da medicação intracanal reduziu em 100 por cento a contaminação por E. faecalis. O grupo que recebeu a medicação intracanal de hidróxido de cálcio por 14 dias permitiu o crescimento de pequeno número de bactérias entre as sessões, mas sem diferença estatística entre os grupos.

The influence of the surgical operating microscope in locating the mesiolingual canal orifice: a laboratory analysis

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.

Analysis of the film thickness of a root canal sealer following three obturation techniques

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 percent 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

Penetraçäo intratubular de cimentos endodônticos / Intratubular penetration of root canal sealers

Este estudo foi desenvolvido para avaliar a capacidade de penetraçäo 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 1mm do ápice radicular. Durante a limpeza e modelagem, todos os dentes foram irrigados com 10 ml de hipoclorito de sódio a 5,25 por cento. Os dentes foram divididos em 4 grupos, sendo 1 para cada tipo de cimento. Estes grupos foram entäo subdivididos em funçäo do uso ou näo de EDTA a 17 por cento previamente à obturaçäo dos canais radiculares, para a remoçäo da lama dentinária. Todos os dentes foram obturados pela técnica da onda de condensaçäo com cone médio calibrado. Após obturaçäo, as raízes foram seccionadas no sentido mesio-distal e foi escolhida a secçäo de melhor qualidade visual. Estas foram entäo analisadas em microscopia eletrônica de varredura (MEV), sendo o foco de observaçäo sempre a interface dentina material obturador. Após obtençäo 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 penetraçäo nos túbulos dentinários, sendo os piores resultados apresentados pelo grupo que se utilizou o Sealapex. Os resultados foram avaliados estatisticamente pelo teste de SPEARMAN, o qual mostrou diferença estatisticamente significante (P0,01) entre os grupos que o EDTA foi utilizado

Análise da plastificaçäo e deformaçäo da guta-percha em três técnicas de obturaçäo / Plasticity and deformation analysis of guta-percha in three filling techniques

Quarenta e cinco blocos de resina simulando canais radiculares curvos foram instrumentados pela técnica anatômica simplificada e obturados pela condensaçäo lateral, compressäo hidráulica e sistema Thermafil. Posteriormente, foram selecionados transversalmente em cinco diferentes níveis e analisado o aspecto final da guta-percha (plastificaçäo e deformaçäo) com o auxílio do microscópio de luz evidente. Nenhuma das técnicas apresentou homogeneidade da massa obturada e perfeita adaptaçäo às paredes do canal. O sistema thermafil apresentou o melhor resultado, seguido da compressäo hidráulica e condensaçäo lateral

Tratamento endodôntico em sessäo única nas faculdades de Odontologia brasileiras / One-visit endodontic therapy in Brazilian dentistry college

Tendo em vista a polêmica que ainda causa a realizaçäo do tratamento dos canais com necrose e lesäo apical em uma única sessäo, os coordenadores dos cursos de Endodontia das Faculdades Brasileiras receberam um questionário que objetivou verificar o percentual de tal procedimento em suas clínicas, possibilitando a realizaçäo de um panorama nacional da filosofia da obturaçäo imediata em dentes necróticos com lesäo. Pôde-se comprovar que a maioria dos cursos de graduaçäo de Endodontia näo realiza a obturaçäo imediata em dentes necróticos com lesäo periapical, mesmo após realizarem os passos essenciais que fundamentam cientificamente tal conduta

Avaliaçäo do grau de limpeza obtido por duas técnicas de instrumentaçäo / A study of cleaning ability of two preparation techniques

Este trabalho teve como objetivo analisar a capacidade de remoçäo de smear layer e debris, no terço apical, comparando-se duas técnicas de instrumentaçäo. Vinte e seis raízes mesio-vestibulares de primeiros molares superiores foram selecionadas para a realizaçäo desta pesquisa. A análise da superfície dentinária foi realizada frente ao microscópio eletrônico de varredura. Debris e smear layer foram previamente definidos e, portanto, analisados distintamente. Os resultados demonstraram näo haver diferenças entre os dois grupos em relaçäo ao smear layer. Entretanto, já em relaçäo à remoçäo de debris, a Técnica Anatômica Simplificada apresentou resultados melhores que a Técnica Step-Back

Tratamento endodôntico em sessäo única / Endodontic treatment in single section

O presente estudo avalia a situaçäo do tratamento endodôntico em sessäo única de dentes necrosados com lesäo apical nas Universidades dos Estados Unidos da América. Foi enviada a cada Universidade uma carta explicativa com um questionário contendo 8 perguntas objetivas e 1 pergunta subjetiva. Totlizaram 61 cartas enviadas e 47 respondidas. A partir dos resultados concluímos que o tema ainda gera certa polêmica, porém a maior parte das Universidades pratica o tratamento de dentes sem vitalidade pulpar e com lesäo periapical em sessäo única