Introdução: A TB pulmonar com baciloscopia negativa (TPBN) representa 30-60% de todos os casos de TB. A mortalidade destes pacientes pode atingir 25% em populações com alta prevalência de infecção por HIV, e 10-20% da transmissão da TB, em níveis populacionais são atribuídos a casos de TPBN. Métodos: Um estudo retrospectivo foi desenvolvido para avaliar as características epidemiológicas, clínicas e radiológicas de pacientes com TPBN e comparar com pacientes diagnosticados como tendo TB pulmonar com baciloscopia positiva (TPBP). Todos os pacientes adultos (≥ 18 anos) com cultura positiva para Mycobacterium tuberculosis, e diagnóstico de TB pulmonar foram incluídos no estudo. Resultados: 198 pacientes preencheram os critérios do estudo (cultura positiva para Mycobacterium tuberculosis) e foram incluídos na análise. Destes, 69 (34,8%) tiveram cultura positiva (TPBP) e 129 (65,2%) cultura negativa (TPBN). Numa análise univariada, tosse, dispneia e hemoptise foram menos frequentes nos pacientes com baciloscopia negativa, em comparação com os com TPBP. Num modelo multivariável, não ter tosse e não ter padrão radiológico típico de TB foram características independentemente associadas com o diagnóstico de TPBN. Conclusões: Encontramos uma prevalência muito alta de TPBN entre pacientes com TB, num local com alta prevalência de TB e HIV. A ausência de tosse na presença de outros sintomas sugestivos de TB, e não ter padrão radiológico típico de TB foram preditores independentes para TPBN. / Introduction: Smear-negative pulmonary TB (SNPT) represents 30-60% of all pulmonary TB cases. The mortality of these patients can reach 25% in populations with high prevalence of HIV infection, and 10-20% of TB transmission at the population level are attributable to SNPT cases. Methods: We conducted a retrospective study to evaluate epidemiological, clinical, and radiological characteristics of patients with SNPT and to compare these with patients who were diagnosed as having smear-positive pulmonary TB (SPPT). All adult patients (≥ 18 years old) with a positive culture for Mycobacterium tuberculosis, and a diagnosis of pulmonary TB were included in the study. Results: 198 patients met the inclusion criteria (positive culture for Mycobacterium tuberculosis) and were included in the analysis. Of these patients, 69 (34,8%) were smear positive (SPPT) and 129 (65,2%) were smear negative (SNPT). In univariate analysis, cough, dyspnea, and hemoptysis were less frequent in SNPT patients in comparison with SPPT patients. In a multivariate model, having no cough and no radiographic pattern typical of TB were the characteristics independently associated with a diagnosis of SNPT. Conclusions: We found a very high prevalence of SNPT among patients with TB in a setting with high TB and HIV prevalence. The absence of cough in the presence of other symptoms suggestive of TB, and having no radiographic pattern typical of TB where independent predictors of SNPT.

O objetivo do presente estudo foi avaliar a remoção da smear layer e a penetração intratubular do cimento obturador AH Plus utilizando diferentes protocolos de irrigação. Após aprovação do Comitê de Ética em Pesquisa da Faculdade de Odontologia de Ribeirão Preto - FORP/USP, noventa incisivos centrais superiores foram selecionados e fornecidos pelo banco de dentes da mesma instituição. Estes foram radiografados no sentido mésio - distal e vestíbulo - lingual para comprovar a presença de canais únicos, sem curvaturas abruptas, reabsorções ou tratamentos endodônticos prévios. Após a remoção da porção coronal para a obtenção de raízes com comprimentos padronizados de 15 milímetros, os diâmetros anatômicos foram determinados e as instrumentações realizadas por meio da técnica coroa ápice estabelecendo os diâmetros cirúrgicos utilizando 3 instrumentos acima dos anatômicos. Durante este processo, os espécimes foram divididos em seis grupos de acordo com os protocolos de irrigação: Grupo 1 (controle - n. 15) - 2,5ml de água destilada a cada troca de instrumentos e 2,5ml de água destilada por 3 minutos ao final da instrumentação; Grupo 2 (n. 15) - 2,5ml de hipoclorito de sódio a 2,5% a cada troca de instrumentos e 2,5ml de hipoclorito de sódio a 2,5% por 3 minutos ao final da instrumentação; Grupo 3 (n. 15) - 2,5ml de hipoclorito de sódio a 2,5% a cada troca de instrumentos e 2,5ml de EDTA a 17% por 3 minutos ao final da instrumentação; Grupo 4 (n. 15) - 2,5ml de hipoclorito de sódio a 2,5% e 2,5ml de EDTA a 17% a cada troca de instrumentos + 2,5ml de EDTA a 17% por 3 minutos ao final da instrumentação; Grupo 5 (n. 15) - 2,5ml de hipoclorito de sódio a 2,5% a cada troca de instrumentos e 2,5ml de ácido cítrico a 10% por 3 minutos ao final da instrumentação; Grupo 6 (n. 15) - 2,5ml de hipoclorito de sódio a 2,5% e 2,5ml de ácido cítrico a 10% a cada troca de instrumentos + 2,5ml de ácido cítrico a 10% por 3 minutos ao final da instrumentação. Após esta fase, cinco espécimes de cada grupo foram clivados no sentido mésio - distal para avaliação da remoção da smear layer em microscopia eletrônica de varredura por meio da análise de 3 imagens de cada terço em aumentos de 300, 1000 e 2000 vezes. Esta variável foi determinada por um score qualitativo estabelecido pelo consenso de 3 avaliadores calibrados. Os demais espécimes foram obturados pela técnica de condensação lateral com cones principais correspondentes ao último instrumento associados ao cimento AH Plus corado com Rodamina B, cones acessórios B8 e mantidos em ambiente com 100% de umidade por 7 dias. Em seguida, os espécimes foram seccionados transversalmente para obtenção de slices de aproximadamente 2mm de espessura em cada terço (cervical, médio e apical) e as faces cervicais submetidas a um tratamento metalográfico para análise da penetração intratubular do cimento obturador em microscopia confocal a laser. Os melhores índices de remoção de smear layer e as maiores porcentagens de penetração intratubular do cimento foram obtidos pelos grupos onde as soluções quelantes foram utilizadas (G3, G4, G5 e G6) com diferenças estatisticamente significantes (p<0,05) em relação aos grupos onde utilizou - se somente a água destilada (G1) e o hipoclorito de sódio a 2,5% (G2) durante o processo de instrumentação. Não foram observadas vantagens em relação ao uso associado do EDTA a 17% e do ácido cítrico a 10% ao hipoclorito de sódio pela ausência de diferenças estatísticas significantes entre os grupos 3 e 4 e 5 e 6, respectivamente. / The aim of this study was to evaluate the smear layer removal and tubular dentine sealer penetration of AH Plus after different irrigation protocols. After approval of the study by the Ethics Committee of the Ribeirão Preto Dental School - FORP/USP, ninety maxillary central incisors were selected and supplied by the tooth bank of the same institution. The teeth were radiographed in the mesiodistal and buccolingual directions to verify the presence of single canals, without abrupt curvatures, resorption or previous endodontic treatment. The coronal portion was removed and roots lengths were standardized at 15 mm. The anatomic diameters were then determined and instrumentations were carried out by the crown-down technique, using 3 higher-diameter instruments to establish the surgical diameters. During this process, the specimens were divided into six groups, according to the following irrigation protocols: Group 1 (control - n. 15) - 2.5ml of distilled water at each change of instruments + 2.5ml of distilled water for 3 minutes at the end of the instrumentation; Group 2 (n. 15) - 2.5ml of 2.5% sodium hypochlorite at each change of instruments + 2.5 ml of 2.5% sodium hypochlorite for 3 minutes at the end of the instrumentation; Group 3 (n. 15) - 2.5ml of 2.5% sodium hypochlorite at each change of instruments + 2.5ml of 17% EDTA for 3 minutes at the end of the instrumentation; Group 4 (n. 15) - 2.5ml of 2.5% sodium hypochlorite and 2.5ml of 17% EDTA at each change of instruments + 2.5ml of 17% EDTA for 3 minutes at the end of the instrumentation; Group 5 (n. 15) - 2.5ml of 2.5% sodium hypochlorite at each change of instruments + 2.5ml of 10% citric acid for 3 minutes at the end of the instrumentation; Group 6 (n. 15) - 2.5ml of 2.5% sodium hypochlorite and 2.5 ml of 10% citric acid at each change of instruments + 2.5 ml of 10% citric acid for 3 minutes at the end of the instrumentation. Following this phase, five specimens from each group were cleaved in the mesiodistal direction to evaluate the smear layer removal by scanning electron microscopy. Evaluation was performed by analyzing 3 images of each third at 300, 1000 and 2000X. This variable was determined by a qualitative score established by the consensus of 3 calibrated examiners. The remaining specimens were filled using lateral condensation with AH Plus sealer labeled with Rhodamine B and kept in an environment with 100% humidity for 7 days. Then, the specimens were sectioned to obtain approximately 2 mm thick slices of each third (cervical, middle and apical). The cervical surfaces were subjected to metallographic treatment for analysis of the tubular dentine sealer penetration by confocal laser microscopy. The highest smear layer removal rates and tubular dentine sealer penetration percentages were obtained by the groups that used chelating solutions (G3, G4, G5 and G6). These showed statistically significant differences (p<0.05) compared with the groups that used just distilled water (G1) and 2.5% sodium hypochlorite (G2) during instrumentation. No benefits were observed for the combined use of 17% EDTA or 10% citric acid with 2.5% sodium hypochlorite, considering that there were no statistically significant differences between groups 3 and 4, and between 5 and 6, respectively.

Este estudo teve como objetivo avaliar a capacidade de remoção da smear layer das paredes de canais radiculares instrumentados pelas soluções de soro fisiológico, EDTA a 17%, vinagre de maçã e SmearClear®, nos três níveis radiculares, associadas ou não ao ultra-som. Para tal propósito, foram utilizados 70 dentes caninos humanos superiores e inferiores extraídos os quais tiveram suas coroas removidas. O comprimento de trabalho foi determinado pela visualização da ponta de uma lima tipo K com diâmetro 10 no forame apical, subtraindo-se 1 milímetro dessa medida. Para o preparo biomecânico, instrumentou-se os dentes com o sistema rotatório ProTaper®, pela técnica coroa-ápice, até o instrumento F5, irrigando os canais com hipoclorito de sódio a 2,5% a cada troca de instrumento. Os dentes foram divididos aleatoriamente em 6 grupos de 10 dentes e 2 grupos controle de 5 dentes de acordo com o método de irrigação final a serem testados: Grupo 1 (controle) Soro fisiológico por 3 minutos sem ultra-som; Grupo 2 - (controle) Soro fisiológico por 3 minutos, sendo o primeiro minuto ativado pelo ultra-som; Grupo 3 - EDTA a 17% por 3 minutos sem ultra-som; Grupo 4 - EDTA a 17% por 3 minutos, sendo o primeiro minuto ativado pelo ultra-som; Grupo 5 - Vinagre de maçã por 3 minutos sem ultra-som; Grupo 6 - Vinagre de maçã por 3 minutos, sendo o primeiro minuto ativado pelo ultra-som; Grupo 7 - SmearClear® por 1 minuto sem ultra-som; Grupo 8 - SmearClear® por 1 minuto ativado pelo ultra-som. Em seguida, os dentes foram irrigados com hipoclorito de sódio a 2,5% e soro fisiológico e secos com cones de papel absorvente. As raízes foram seccionadas longitudinalmente e preparadas para a microscopia eletrônica de varredura com o aumento de 750 vezes. Fotomicrografias foram obtidas dos terços cervical, médio e apical e analisadas por três examinadores para a atribuição de escores para posterior análise estatística. Concluiu-se que as soluções de EDTA e SmearClear® foram efetivas na remoção da smear layer do canal radicular, com pequena vantagem numérica do EDTA, entretanto, sem diferença estatisticamente significante entre elas. O soro fisiológico apresentou resultado significativamente inferior comparado às demais soluções irrigadoras. O vinagre de maçã se mostrou ligeiramente inferior ao SmearClear® e ao EDTA, apresentando diferença estatisticamente significante ao EDTA no terço cervical. O uso do ultra-som não promoveu uma melhora significante na capacidade de limpeza de todas as soluções irrigadoras testadas. Em todos os grupos, o resultado menos favorável em relação à remoção da camada de smear layer foi observado no terço apical do canal radicular, com diferença estatisticamente significante em relação ao terço cervical. / The aim of this study was to evaluate the smear layer removal from instrumented root canal walls by saline solution, 17% EDTA, apple vinegar and SmearClear®, at three radicular levels, with or without ultrasonics. For that purpose, 70 upper and lower human canines were used, which had their crowns removed. The working length was established by visualizing the tip of a 10 K-type file at the apical foramen, by reducing 1 mm from this measurement. For preparation of root canal, the teeth were instrumented with rotatory files ProTaper®, using the crown-down technique, up to F5 instrument, irrigating with 2,5% sodium hypochlorite between each instrument change. The teeth were randomly divided into 6 groups of 10 teeth each and 2 control groups of 5 teeth according to the final irrigation protocol: Group 1 (control) Saline solution for 3 minutes without ultrasonics; Group 2 (control) Saline solution for 3 minutes, with ultrasonic activation for the first minute; Group 3 17% EDTA for 3 minutes without ultrasonics; Group 4 17% EDTA for 3 minutes, with ultrasonic activation for the first minute; Group 5 Apple vinegar for 3 minutes without ultrasonics; Group 6 Apple vinegar for 3 minutes, with ultrasonic activation for the first minute; Group 7 - SmearClear® for 1 minute without ultrasonics; Group 8 - SmearClear® for 1 minute with ultrasonic activation. Subsequently, the teeth were irrigated with 2,5% sodium hypochlorite and dried with paper points. The teeth were split open longitudinally and prepared for scanning electron microscopy at magnification of 750X. Photomicrographs were taken from coronal, middle and apical thirds and analyzed by three examiners for scores attribution for statistical analysis. It was concluded that EDTA and SmearClear® were efficient for smear layer removal from root canals, with a discrete superiority of EDTA, however, without statistical significance. The saline solution showed significant inferior results compared with the others solutions. Apple vinegar was slightly inferior to SmearClear® and EDTA, with statistical difference observed between apple vinegar and EDTA in coronal third. The ultrasonics did not enhance the cleaning ability of all the irrigating solutions tested. In all cases, the least favorable result regarding smear layer removal was observed in the apical third of the root canal, with statistically significant differences in the coronal third.

MPH, University of the Witwatersrand, Faculty of Health Sciences / Introduction Sex workers are considered to be a high risk group in the acquisition and transmission of sexually transmitted infections which include Human Immunodeficiency Virus (HIV) and Human Papillomavirus (HPV). Infection with HPV has been clearly established as a causative agent that infects the cells of the cervix and slowly causes cellular changes (dysplasia) or abnormal cells that can later develop into cancer. Women who are HIV positive are thought to be at higher risk of having HPV infection, and subsequently also at higher risk of having abnormal cervical lesions. Objectives The main focus of this study is to describe the prevalence of abnormal Pap-smears among sex workers and to further identify the difference between Pap-smear results of sex workers who are HIV-positive and HIV negative. Methods This is a retrospective descriptive study, where data was obtained from sex workers records from January 2004 to December 2006. The study population included all sex workers who attended the Esselen Street Clinic and sex worker outreach clinic in Hillbrow, in the inner-city of Johannesburg. Three hundred and nine records were randomly selected, of which 200 met the inclusion criteria. Data was collected on socio-demographic information including the age and place of residence, laboratory results (Pap-smear and HIV) and history of sexually transmitted infection at the last physical examination. Extracted data was captured in excel spreadsheet and transferred to Stata Computer Package software version 9.0 for data management and analysis. Descriptive analysis included frequency distributions of categorical variables (e.g. residence, Pap-smear results, HIV status and age group) and summary statistics of continuous variables (e.g. age). Pearson chi-square test or Fisher Exact test when necessary, where conducted to obtain proportions of the sex workers with abnormal Pap-smear results corresponding to each category of the explanatory variables for example age, HIV status and place of residence or business or business transactions. For continuous explanatory variables, such as age, two sample t-tests were used to determine differences between sex workers in terms of abnormal and normal Pap-smears. In all statistical considerations, a probability level of ≤0.05 was used. Results There were 200 records which were analysed to achieve the study objectives. These included 146 records of HIV positive (73%) and 54 of HIV negative sex workers (27%). Their ages ranged from 18 to 45 years with a mean of 26.85 years and median of 26.0 years. More than 70% (n=141) of the sex workers were below the age of 30 years. More than two thirds of sex workers lived in hotels and almost 90% was considered to be symptomatic for STIs. Eighty-eight (44%) of the sex workers were found to have had an abnormal smear result, of whom 58 (65.9%) were below the age of 30 years. Age, as a continuous variable, and place of residence (living on the street) was found to be statistically significantly associated with having an abnormal smear result. However, age (being older than 30), having symptoms of an STI and being HIV positive was not found to be statistically significantly associated with having an abnormal Pap-smear result. Conclusion This study has shown that the prevalence of abnormal Pap-smears among Hillbrow sex workers was high, especially in young sex workers. Sex workers who operated from the street were found to have a higher percentage of abnormal smear results as compared to those operating from the brothels and flats, signifying a need for a controlled environment and to improve sex workers access to health care services. No significant association was found between HIV status and abnormal Pap-smears. Further studies are required in this area. The study indicates that they may be a need to review the National Cervical Cancer Screening Policy to take into consideration the needs of high risk population, such as sex workers.

Mi’kmaq women in Nova Scotia are reported to have lower rates of Papanicolaou (Pap) smear screening and have higher rates of cervical cancer compared to non-Aboriginal women. Much of the cervical cancer literature reflects mainstream values and tends to essentialize Aboriginal women as one at-risk homogenous group lacking knowledge about cervical cancer prevention. The primary purpose of this qualitative participatory study was to explore Mi’kmaq women’s and primary healthcare providers’ experiences with Pap smear screening and to consider the broader historical, economic, and socio-political contexts that shape those healthcare experiences. Mi’kmaq women’s experiences accessing Pap screening services, their encounters with healthcare providers and the health care system, and women’s past experiences with Pap smear screening were also explored. This inquiry was grounded in postcolonial feminist perspectives and Indigenous principles in a two-eyed seeing approach. Community facilitators were identified to assist with recruitment and the research process. Women participated in talking circles to learn about and shape the study. Sixteen Mi’kmaq women and five healthcare providers participated in two semi-structured interviews. Five themes were identified from the women: a) Finding Our Way, b) Our Understanding and Perceptions about Pap Smear Screening, c) The Impact of History on Our Health and Healthcare Experiences, d) Healthcare Providers’ Encounters: “Making a Difference in Our Path to Paps,” and e) “The Healthcare System is Complicating Our Going for Paps.” Two themes were identified from healthcare providers: a) Understanding the Realities of Aboriginal Women’s Lives and b) Fostering Aboriginal Women’s Access to Pap Smear Screening. This research contributes to an understanding of the continued impact of wider historical, political, and socioeconomic conditions that have resulted from colonialism, residential schools, and assimilation on Pap smear screening. It reinforces the importance of not essentializing women’s views or experiences and recognizing that some are accessing Pap smear screening regularly in spite of challenging circumstances. Mi’kmaq women have been underrepresented in the previous Pap smear screening literature. It is critical that healthcare providers understand how they can improve access to Pap smear screening and the screening process itself.

<p> <p>&nbsp / </p> </p> <p><font face="Times New Roman" size="3">The aim of this study was to compare the sealing ability of AH Plus sealer to the canal wall in the presence and absence of the smear layer.</font></p>

<p> <p>&nbsp / </p> </p> <p><font face="Times New Roman" size="3">The aim of this study was to compare the sealing ability of AH Plus sealer to the canal wall in the presence and absence of the smear layer.</font></p>

Orientador: José Eduardo Cezar Sampaio / Banca: Carlos Rossa Júnior / Banca: Gibson Luis Pilatti / Resumo: O propósito deste estudo foi avaliar in vitro a eficácia de um gel de EDTA associado ao detergente texapon na remoção da "smear layer" avaliando-se os fatores concentração da substância, tempo e forma de aplicação. "Smear layer" foi produzida experimentalmente em dentes extraídos. As amostras obtidas receberam a aplicação do gel de EDTA nas seguintes concentrações: controle (soro fisiológico), 5%, 10%, 15%, 20%, 24%. Para cada grupo experimental os tempos de aplicação foram de um, dois e três minutos. Quanto à forma de aplicação, foram testadas as maneiras passiva e ativa (pincel). A seguir foram obtidas fotomicrografias em microscópio eletrônico de varredura que foram avaliadas segundo o índice de Sampaio (1999). Os resultados demonstraram que a utilização do gel de EDTA-T removeu mais "smear layer" que o grupo controle. Durante a aplicação passiva, a concentração de 15% foi superior a de 5% e 10%, diferença que não existia durante a aplicação ativa. O tempo de três minutos parece ser o ideal para aplicação do gel de EDTA-T. A forma de aplicação ativa é superior a forma de aplicação passiva. A forma de aplicação parece ser o fator fundamental na remoção da "smear layer", pois influencia os fatores concentração e tempo de aplicação e não é influenciado por eles. / Abstract: The purpose of this study was to evaluate in vitro the efficacy of na EDTA-T gel on smear layer removal evaluating the influence of concentration, application time and application manner. Smear layer was experimentally promoved at extracted teeth. The root fragments assigned one of the EDTA gel concentration tested: control, 5%, 10%, 15%, 20% and 24% . For each concentration, the gel was applied for one, two and three minutes, either in a passive or active manner. Photomicrographs was obtained with scanning electron microscope, which were evaluated using index of Sampaio (1999). The results demonstrated that the EDTA-T gel exhibitted a better smear layer removal than control. During the passive application, concentration of 15% was superior compared to 5% and 10% concentration, but when active application was used, there was no differenceamong the groups. Smear layer removal was more effective when EDTA gel was applied for three minutes. Application manner is the fundamental factor on smear layer removal because influenced concentration and application time and was not influenced by them. / Mestre

O preparo químico-mecânico tem sido essencial no sucesso do tratamento endodôntico. No entanto, atualmente não existe instrumento ou técnica com capacidade de proporcionar a limpeza e a desinfecção dos sistemas de canais em sua totalidade. O objetivo desse estudo foi avaliar a limpeza, tempo, transporte e centralização de preparos de canais radiculares curvos utilizando os sistemas de rotação contínua ProTaper®, de rotação alternada WaveOne® e uma sugestão de técnica híbrida de preparo. Foram selecionadas raízes mesiais de primeiros molares inferiores humanos permanentes extraídos. Após a definição dos ângulos de curvatura e raio, os canais (n=60) foram divididos em três grupos experimentais, conforme sistemas de preparo (ProTaper, WaveOne, WaveOne Técnica Híbrida). O diâmetro apical final foi padronizado em #25. As quantidades de debris e smear layer remanescentes foram analisadas em microscopia eletrônica de varredura, através de escores, e avaliadas estatisticamente por meio do teste de Kruskal–Wallis. Fraturas ou deformações nos instrumentos foram registradas. O tempo de preparo foi cronometrado e analisado através de ANOVA e Tukey. Tomografia computadorizada de feixe cônico pré e pós-operatória foram feitas para mensuração do transporte e centralização dos canais e os resultados obtidos foram avaliados estatisticamente através de ANOVA. Em relação à capacidade de limpeza, os três grupos apresentaram semelhante capacidade em remover debris e formar smear layer, sem diferenças estatísticas (P>0,05) em todas as porções dos canais. O preparo com apenas um instrumento foi significativamente mais rápido do que com sequências de instrumentos (P<0,05). Durante a instrumentação, não ocorreram fraturas, apenas três instrumentos deformaram. Não foram encontradas diferenças no transporte e centralização dos canais entre os sistemas. Sob as condições deste estudo, todos os instrumentos apresentaram uma capacidade de limpeza similar, sendo o instrumento único semelhante aos demais sistemas de sequências de instrumentos, contudo, reduzindo o tempo de preparo de forma significativa. Nenhum instrumento forneceu um debridamento completo. Todos os grupos mostraram-se similares em relação à capacidade de manter a curvatura original do canal. / The chemo-mechanical preparation is essential for successful endodontic treatment. However, currently no instrument can predictably clean the entire root canal system. The aim of this investigation was to assess the cleanliness, preparation time and shaping ability of curved root canals in extracted human molar teeth using rotary full-sequence ProTaper, single-file system WaveOne and a protocol using both systems. Sixty canals had the degree and the radius of curvature determined and were divided into three groups according with preparation systems. Canals were prepared until #25 apical sizes and the shaping ability and the cleaning efficacy were evaluated. The amounts of debris and smear layer were quantified on the basis of a numerical evaluation scale by scanning electron microscope and were analyzed statistically using the Kruskal–Wallis test. Instrument failures were recorded. Preparation time was analyzed statistically using ANOVA and Tukey. Teeth were scanned pre- and post-operatively using computed tomography to measure shaping changes and the obtained results were statistically analyzed using ANOVA. For debris removal and smear layer remaining, the results for three groups were similar and not significantly different for the all parts of the canals (P> 0.05). Instrumentation with WaveOne was significantly faster than with other instruments (P< 0.05). During preparation, no file fractured, three suffered deformations. No difference in the transportation and centering ratio was found between the systems. Under the conditions of this study, all instruments maintained the original canal curvature well and were safe to use. A single-file system presented as good cleanliness capacity as others, reducing the preparation time significantly, although none could provide a complete debridement.

O preparo químico-mecânico tem sido essencial no sucesso do tratamento endodôntico. No entanto, atualmente não existe instrumento ou técnica com capacidade de proporcionar a limpeza e a desinfecção dos sistemas de canais em sua totalidade. O objetivo desse estudo foi avaliar a limpeza, tempo, transporte e centralização de preparos de canais radiculares curvos utilizando os sistemas de rotação contínua ProTaper®, de rotação alternada WaveOne® e uma sugestão de técnica híbrida de preparo. Foram selecionadas raízes mesiais de primeiros molares inferiores humanos permanentes extraídos. Após a definição dos ângulos de curvatura e raio, os canais (n=60) foram divididos em três grupos experimentais, conforme sistemas de preparo (ProTaper, WaveOne, WaveOne Técnica Híbrida). O diâmetro apical final foi padronizado em #25. As quantidades de debris e smear layer remanescentes foram analisadas em microscopia eletrônica de varredura, através de escores, e avaliadas estatisticamente por meio do teste de Kruskal–Wallis. Fraturas ou deformações nos instrumentos foram registradas. O tempo de preparo foi cronometrado e analisado através de ANOVA e Tukey. Tomografia computadorizada de feixe cônico pré e pós-operatória foram feitas para mensuração do transporte e centralização dos canais e os resultados obtidos foram avaliados estatisticamente através de ANOVA. Em relação à capacidade de limpeza, os três grupos apresentaram semelhante capacidade em remover debris e formar smear layer, sem diferenças estatísticas (P>0,05) em todas as porções dos canais. O preparo com apenas um instrumento foi significativamente mais rápido do que com sequências de instrumentos (P<0,05). Durante a instrumentação, não ocorreram fraturas, apenas três instrumentos deformaram. Não foram encontradas diferenças no transporte e centralização dos canais entre os sistemas. Sob as condições deste estudo, todos os instrumentos apresentaram uma capacidade de limpeza similar, sendo o instrumento único semelhante aos demais sistemas de sequências de instrumentos, contudo, reduzindo o tempo de preparo de forma significativa. Nenhum instrumento forneceu um debridamento completo. Todos os grupos mostraram-se similares em relação à capacidade de manter a curvatura original do canal. / The chemo-mechanical preparation is essential for successful endodontic treatment. However, currently no instrument can predictably clean the entire root canal system. The aim of this investigation was to assess the cleanliness, preparation time and shaping ability of curved root canals in extracted human molar teeth using rotary full-sequence ProTaper, single-file system WaveOne and a protocol using both systems. Sixty canals had the degree and the radius of curvature determined and were divided into three groups according with preparation systems. Canals were prepared until #25 apical sizes and the shaping ability and the cleaning efficacy were evaluated. The amounts of debris and smear layer were quantified on the basis of a numerical evaluation scale by scanning electron microscope and were analyzed statistically using the Kruskal–Wallis test. Instrument failures were recorded. Preparation time was analyzed statistically using ANOVA and Tukey. Teeth were scanned pre- and post-operatively using computed tomography to measure shaping changes and the obtained results were statistically analyzed using ANOVA. For debris removal and smear layer remaining, the results for three groups were similar and not significantly different for the all parts of the canals (P> 0.05). Instrumentation with WaveOne was significantly faster than with other instruments (P< 0.05). During preparation, no file fractured, three suffered deformations. No difference in the transportation and centering ratio was found between the systems. Under the conditions of this study, all instruments maintained the original canal curvature well and were safe to use. A single-file system presented as good cleanliness capacity as others, reducing the preparation time significantly, although none could provide a complete debridement.