Introdução: Os objetivos do presente estudo foram comparar a extrusão apical de detritos durante o preparo apical #25 com os sistemas Twisted File Adaptive (TFA), WaveOne Gold (WOG) e técnica manual (TM), registrar o tempo de preparo; e comparar WOG com TFA em relação ao transporte do canal radicular (TCR) e centralização (CR) com diâmetros apicais #25 e #35. Metodologia: Quarenta e cinco canais mésio-vestibulares de molares inferiores foram preparados e divididos em 3 grupos (n=15) para avaliar extrusão apical. A extrusão de detritos foi quantificada subtraindo-se o peso final do peso inicial dos tubos Eppendorf. TCR e CR foram avaliados em micro-TC com os sistemas TFA e WOG (n=15). A normalidade dos valores obtidos para cada grupo foi verificada usando teste de Kolmogorov-Smirnov. Para quantificar detritos extruídos e tempo de preparo, os dados foram paramétricos, sendo utilizado o Teste ANOVA de 1 via e post hoc de Tukey’s. Para avaliar TCR e CR, o teste estatístico foi Mann Whitney e Wilcoxon (α=.05). Resultados: Em relação aos detritos, o sistema WOG foi associado com menos extrusão em comparação com TM (P<0,05) ou com o sistema TFA (P> 0,05). O tempo de preparo exigido pela TM foi significativamente maior do que o exigido pelas outras técnicas (P<0,05). Não foram encontradas diferenças estatisticamente significantes entre WOG e TFA em relação à centralização em todos os níveis, quando usado diâmetro apical #25 ou #35 (P> 0,05). Para TCR, diferença significativa foi encontrada entre TFA e WOG a 1 e 7mm com diâmetro apical #25 e #35 (P<0,05). Foi encontrada diferença significante para TFA em 4mm, quando os diâmetros apicais #25 e #35 foram avaliados no mesmo sistema (P <0,05). Conclusões: Todos os sistemas de instrumentação causaram extrusão de detritos apicais em algum grau. TFA e WOG podem ser usados em canais radiculares curvos com segurança com diâmetros apicais# 25 ou 35. / Introduction: The aims of this study were to assess the amount of apically debris during root canal preparation with apical size #25 with the Twisted File Adaptive system (TFA), WaveOne Gold system (WOG) and manual technique (MT), and recorded working time; and to assess WOG with TFA in relation to root canal transportation (RCT) and centering ratio (CR) with apical diameters # 25 and # 35. Methods: Forty-five mesiobuccal root canals of mandibular molars were prepared and assigned into 3 groups (n = 15) to evaluate apical extrusion. Debris extrusion was quantified by subtracting the final from the initial weight of the Eppendorf tubes. RCT and CR were evaluated in Micro-TC with the TFA and WOG systems (n = 15). The normality values obtained for each group were tested using the Kolmogorov-Smirnov test. To quantify extruded debris and preparation time, the data were parametric, using the Tukey's 1-way and post-hoc ANOVA test. To evaluate RCT and CR, the statistical test was Mann Whitney (α =.05). Results: The WaveOne Gold reciprocating single-file system was associated with less extrusion of debris compared with hand files (P < 0.05) or with the Twisted File Adaptive system (P > 0.05). The preparation time required by hand files was significantly longer than that required by the other techniques (P < 0.05). No significant differences were found between WOG and TFA regarding CR for all levels when used #25 or #35 apical size preparation (p>0.05). For RCT, significant difference was found among TFA and WOG at 1 mm and 7 mm with diameter apical #25 and #35. (p<0.05). Statistically different for the TFA in 4 mm was observed when the apical diameters # 25 and # 35 was evaluated in the same system (P <0,05). Conclusions: All of the instrumentation systems caused apical debris extrusion to some degrees. TFA and WOG can be used in curved root canals with safety with #25 or 35 apical diameters.

Este estudo objetivou avaliar a influência do diâmetro do forame e do instrumento endodôntico na leitura odontométrica de dois aparelhos localizadores apicais eletrônicos. Foram utilizados 40 dentes incisivos inferiores, divididos em 4 grupos, de acordo com o diâmetro do forame apical (100, 200, 300 e 400 µm). Após a abertura coronária desses dentes e o acesso aos canais radiculares, realizou-se a medição do comprimento dos mesmos com auxílio de um microscópio clínico com ampliação de 7,8X, da incisal até que a ponta da lima surgisse no forame apical. Os dentes foram colocados em potes individuais contendo solução de ágar a 1% em solução salina de fosfato tamponado, mantendo-se cerca de 2/3 de suas raízes imersas na solução para que pudesse ser feita a leitura com o Root ZX® (J.Morita, Japão) e o NovApex® (Fórum, Israel). Os mesmos foram medidos com limas nº10 até que a distância de 0,5 mm do ápice fosse acusada no display dos aparelhos. Uma outra medida foi realizada nos dentes utilizando-se lima nº10 e limas com diâmetros correspondentes ao diâmetro dos forames (200µm, 300µm e 400µm). Para a análise estatística foi empregado o teste de Análise de Variância a dois critérios para o confronto global entre os aparelhos e o emprego da lima nº10 em todos os dentes e teste de Tukey para as comparações individuais. Os resultados demonstraram diferença estatística na precisão dos dois aparelhos com um resultado mais preciso para o Root ZX® (p<0,05). Dentes com forame, de menor diâmetro, apresentaram uma medida mais precisa com o localizador apical e dentes com forame de maior diâmetro apresentaram uma maior discrepância na medida. O emprego de limas tipo K nº10 nos dentes com forames de diâmetros maiores apresentaram maior precisão na medição quando comparadas às limas coincidentes aos diâmetros dos forames para o aparelho Root ZX®. Para o NovApex® esta correlação só passou a ocorrer a partir da lima nº40. / This study evaluated the influence of foramen diameter and endodontic instrument size on the odontometry reading of two electronic apical measuring devices. Forty mandibular incisors were used, which were divided into four groups according to the apical foramen diameter (100, 200, 300 and 400µm). After coronal opening of these teeth and access to the root canals, the root canal length was measured with aid of a clinical microscope with 7.8x magnification, from the incisal edge until the file tip reached the apical foramen. Ten teeth with 100-µm diameter were placed in individual jars containing 1% agar solution in phosphate-buffered saline, maintaining around 2/3 of their roots immersed in the solution to allow measurement with Root ZX (J. Morita, Japan) and NovApex (Forum, Israel). Teeth were measured with files n. 10 until the distance of 0.5mm from the apex was indicated by the device. Another measurement was performed on the other thirty teeth with files n. 10 and files with diameters corresponding to the foramen diameters (200µm, 300µm and 400µm). Statistical analysis was performed by two-way analysis of variance for overall comparison between the devices and employment of file n. 10 in all teeth, and Tukey test for individual comparisons. The results demonstrated statistical difference in the precision of both devices, with a more accurate result for Root ZX (p<0.05). Teeth with narrower foramina presented a more accurate measurement with the apical measuring device, and teeth with wider foramina presented larger discrepancy in the measurement. Utilization of K file n. 10 in teeth with wider foramina showed more accurate measurements compared to files with size corresponding to the foramen diameters with the Root ZX® device. With the NovApex® device, this correlation was only observed with file n. 40.

Introdução: Poucos estudos investigaram o papel da periodontite apical (PA) como fator de risco para doenças cardiovasculares (DCV) e mortalidade associada. Esta tese teve o objetivo de avaliar a associação entre variáveis endodônticas, com ênfase na PA, e DCV, estando dividida em quatro diferentes artigos: 1- uma revisão sistemática e meta-análise investigando se indivíduos com PA apresentam alteração nos níveis séricos de marcadores inflamatórios (MI); 2- um coorte retrospectivo avaliando a associação entre variáveis endodônticas e eventos cardiovasculares (ECV) incidentes, incluindo morte por ECV, em participantes do Estudo Longitudinal de Envelhecimento de Baltimore (BLSA); 3- um estudo transversal verificando se perda dentária e a condição de saúde bucal autorrelatada (SROH) estão associados com a carga aterosclerótica (CAB) em indivíduos do sul do Brasil; 4- um estudo de validação do auto-relato de tratamento endodôntico (SRHET) como método de identificar a presença de tratamento endodôntico (TE) e a presença de PA detectável radiograficamente, em participantes do BLSA. Métodos: No Artigo 1, as bases de dados MEDLINE, Embase, Cochrane e Pubmed foram pesquisadas, sem restrição de idioma. A partir de critérios de inclusão e exclusão, dois revisores avaliaram a qualidade dos estudos pela Escala de Newcastle-Ottawa. A principal variável de desfecho da meta-análise foi o nível sérico de MI em indivíduos com PA versus controles saudáveis ou em indivíduos com PA antes versus após o tratamento da PA. No Artigo 2, 278 indivíduos com exames médicos e odontológicos foram avaliados. Doença periodontal (DP) e perda dentária foram aferidas. O número total de dentes com PA e TE foi apurado através de radiografias panorâmicas. A carga endodôntica (EB) foi calculada a partir da soma de PA e TE. O desfecho ECV incidentes incluiu angina, infarto agudo do miocárdio e morte por ECV. Os participantes foram monitorados por até 44 anos (média=17,4±11,1 anos). Riscos relativos (RR) foram calculados por modelos de regressão de Poisson, estimando a relação entre PA, TE, EB e ECV incidentes. No Artigo 3, 382 indivíduos submetidos a coronarioangiografia foram incluídos. Dados sociodemográficos, fatores de risco cardiovascular e condição de saúde bucal foram coletados por questionário, incluindo dados acerca do SROH. O número de dentes a as medidas antropométricas foram coletadas através de exames clínicos. CAB foi quantificada através do escore de Friesinger (FS). Razões de prevalência (PR) foram calculadas por regressão de Poisson. No Artigo 4, o SRHET foi coletado através de questionário em 247 participantes do BLSA. TE e PA foram determinados através de radiografias panorâmicas. O número total de TE, PA e dentes perdidos foi registrado para cada indivíduo. A validação de SRHET foi determinada com base em ET e PA, separadamente. Acurácia, eficiência, sensibilidade, especificidade, valores preditivos positivos e negativos (+PV, -PV) e razões de verossimilhança positivos e 13 negativos (+LR, -LR) foram calculados por métodos padrão. Resultados: No Artigo 1, dos 531 estudos inicialmente identificados, 20 integraram a análise final. Trinta e um MI foram analisados, sendo IgA, IgM, IgG e CRP os mais comumente investigados. CRP, IL-1, IL-2, IL-6, ADMA, IgA, IgG, e IgM demonstraram níveis elevados em pacientes com PA em comparação com os controles na maioria dos estudos. A meta-análise revelou que: a) os níveis séricos de IgA (P=0,001), IgG (P=0,04), e IgM (P<0,00001) apresentaram-se aumentados em humanos com PA comparados com indivíduos saudáveis; b) os níveis séricos de CRP, IgA, IgE, IgG e IgM não foram estatisticamente diferentes entre pacientes com PA antes e após o tratamento (P>0.05). No Artigo 2, a idade média foi de 55,0±16,8 anos, sendo 51,4% homens. Ao total, 62 participantes (22,3%) desenvolveram ECV. Modelos multivariados, ajustados para idade, gênero, IMC, fumo, hipertensão, dislipidemia, diabetes, DP e perda dentária demonstraram que EB (P=0,035) esteve associada de forma independente com ECV incidentes. No Artigo 3, a idade média foi de 60,3±10,8 anos, com 63,2% de homens. Modelos multivariados, ajustados para idade, sexo, fumo, hipertensão, diabetes e dislipidemia mostraram que a condição ruim de SROH (P=0,03) e perda dentária (P=0,02) foram associados de modo independente com a CAB. No Artigo 4, 229 participantes compuseram as análises de TE e 129 as análise de PA. Os valores de validação do SRHET foram: sensibilidade (TE=0,91; PA=0,78), especificidade (TE=0,89; PA=0,69), +PV (TE=0,82; PA=0,35), -PV (TE=0,95; PA=0,94), +LR (TE=8,39; PA=2,51) e -LR (TE=0,09; PA=0,32). Conclusões: O Artigo 1 mostrou que a evidência disponível é limitada mas consistente, sugerindo que a PA está associada a um aumento nos níveis séricos de CRP, IL-1, IL-2, IL-6, ADMA, IgA, IgG, e IgM em humanos. Estes achados indicam que a PA pode contribuir para uma resposta imune em nível sistêmico, com possível aumento no risco vascular global. Os resultados do Artigo 2 demonstraram que embora as variáveis PA e ET não estiveram associadas com o desenvolvimento de ECV, a variável EB foi um preditor independente da incidência de ECV entre participantes do BLSA. No Artigo 3, perda dentária e uma condição ruim de SROH foram associados de modo independente com a CAB, sugerindo que a associação entre doenças bucais e aterosclerose está presente entre indivíduos do sul do Brasil. O Artigo 4 demonstrou que o SRHET foi um método acurado para identificar indivíduos com TE, mas um preditor fraco da presença de PA entre indivíduos do BLSA. O uso do SRHET como método de predizer a presença de PA em estudos populacionais deve ser vista com cautela. Esta tese identifica a necessidade do desenvolvimento de estudos prospectivos controlados de larga escala que avaliem a possível redução no risco de DCV frente ao tratamento da PA. / Introduction: Few studies have investigated the role of apical periodontitis (AP) as a risk factor for cardiovascular diseases (CVD) and related mortality. This thesis aimed to evaluate the association between apical periodontitis (AP) and cardiovascular diseases (CVD) and was divided in four different articles: 1- a systematic review and meta-analysis investigating evidence to support whether AP can modify systemic levels of inflammatory markers (IM) in humans; 2- a retrospective cohort evaluating whether the presence of AP and endodontic treatment (ET) was associated with incident cardiovascular events (CVE) on participants in the Baltimore Longitudinal Study of Aging (BLSA); 3- a cross-sectional study testing the hypothesis that poor self-reported oral health (SROH) and tooth loss are positively associated with coronary atherosclerotic burden (CAB) in a group of southern Brazilian patients; 4- a study quantifying the validity of self-reported history of endodontic treatment (SRHET), as reported in the BLSA, as a method to identify individuals who experienced ET and individuals who present with AP. Methods: In Article 1, the MEDLINE, Embase, Cochrane and Pubmed databases were searched, with no language restriction. Based on inclusion and exclusion criteria, two reviewers rated the quality of each study based on the Newcastle-Ottawa Scale. The primary outcome variable for meta-analysis was determined by the serum levels of IM in AP subjects versus healthy controls or in AP subjects before versus after treatment intervention. In Article 2, 278 subjects who received complete medical and dental examinations were evaluated. Periodontal disease (PD) and missing teeth were recorded. Total number of AP and ET were determined from panoramic radiographs. Endodontic burden (EB) was calculated as the sum of AP and ET. Main outcome incident CVE included angina, myocardial infarction and cardiovascular-related death. Participants were monitored for up to 44 years (mean=17.4±11.1 years) following the dental examination. Relative Risks (RR) were calculated through Poisson regression models, estimating the relationship between AP, ET, EB and incident CVE. In Article 3, 382 subjects undergoing coronary angiography were included. Socio-demographic characteristics, cardiovascular risk factors and oral health status were collected using a standardized questionnaire, including data on SROH. Number of teeth and anthropometric measures were collected through clinical examinations. CAB at coronary angiography was quantified using the Friesinger score (FS). Prevalence ratios (PR) were calculated with Poisson regression analyses. In Article 4, SRHET was collected through the BLSA questionnaire in 247 participants. Data on ET and AP were determined from panoramic radiographs. The total number of ET, AP and missing teeth were recorded for each individual. Validity of SRHET was determined based on ET and AP, separately. Accuracy, efficiency, sensitivity, specificity, positive and negative predictive values (+PV, -PV) and positive and negative likelihood ratios (+LR, -LR) were 15 calculated according to standard methods. Results: In Article 1, among the 531 initially identified papers, 20 comprised the final analysis. Thirty-one IM were analyzed, with IgA, IgM, IgG and CRP being most commonly investigated. CRP, IL-1, IL-2, IL-6, ADMA, IgA, IgG, and IgM were shown to be increased in patients with AP compared to controls in most studies. Meta-analyses showed that: a) serum levels of IgA (P=0.001), IgG (P=0.04), and IgM (P<0.00001) were increased in humans with AP compared to healthy controls and b) serum levels of CRP, IgA, IgE, IgG and IgM were not significantly different between patients with AP before and after treatment (P>0.05). In Article 2, mean age at dental examination was 55.0±16.8, with 51.4% males. A total of 62 participants (22.3%) developed CVE. Multivariate models, adjusted for covariates age, sex, BMI, smoke, hypertension, dyslipidemia, diabetes, PD and tooth loss showed that EB (P=0.035) was independently associated with incident CVE. In Article 3, mean age was 60.3±10.8 years, with 63.2% males. Multivariate models, adjusted for age, gender, smoking, hypertension, diabetes and dyslipidemia showed that poor SROH (P=0.03) and tooth loss (P=0.02) were independently associated with CAB. In Article 4, 229 participants were available for ET analysis and 129 for AP analysis. The SRHET validity values were: sensitivity (ET=0.915; AP=0.782), specificity (ET=0.891; AP=0.689), +PV (ET=0.824; AP=0.353), -PV (ET=0.949; AP=0.936), +LR (ET=8.394; AP=2.514) and -LR (ET=0.095; AP=0.316). Conclusions: The systematic review showed that available evidence is limited but consistent, suggesting that AP is associated with increased levels of CRP, IL-1, IL-2, IL-6, ADMA, IgA, IgG, and IgM in humans. These findings indicate that AP may contribute to a systemic immune response not confined to the localized lesion, with a possible role in patient's global vascular risk. Results from Article 2 demonstrated that although AP and ET were not individually associated with the development of CVE, EB in mid-life was an independent predictor of CVE among community-resident participants in the BLSA. In Article 3, poor SROH and tooth loss were independently associated with CAB, suggesting that the association between oral diseases and atherosclerosis is also present among southern Brazilian individuals. In Article 4, SRHET was found to be a highly accurate method to predict ET but a weak predictor of the presence of AP among participants in the BLSA. Thus, the use of SRHET as a predictor of AP in large populational studies must be considered with careful. Finally, future large-scale prospective controlled studies are required to evaluate CVD risk reduction with the treatment of AP.

O objetivo no presente estudo foi avaliar, por meio de tomografia computadorizada cone beam, o transporte do canal, o aumento da área do canal e o desgaste da dentina intrarradicular na região voltada para a furca de molares inferiores com diferentes instrumentos e verificar a influência do desgaste na determinação do instrumento apical inicial (IAI) por meio de MEV. Os dentes foram dispostos (n=10) em três bases de resina (corpos de prova) de acordo com o tipo de preparo cervical e submetidos ao escaneamento em tomógrafo computadorizado de feixe cônico. Em seguida foi realizado o preparo cervical nos canais mesiais G1: Gattes-Glidden 2 e 3 nos canais mesiais e 3 e 4 no distal; G2 LA Axxess 20.06 e 35.06 nos canais mesiais e 35.06 e 45.06 no canal distal. Concluído o preparo do terço cervical os corpos de prova foram submetidos a novo exame tomográfico. O IAI foi determinado inserindo-se passivamente limas tipo K de aço inox, seqüencialmente a partir da lima #10 até obter a sensação de travamento do instrumento no comprimento de trabalho, em seguida este instrumento foi fixado utilizando-se adesivo à base de cianoacrilato para posterior corte apical e observação em MEV. O índice de centralização não mostrou diferença estatística entre os grupos estudados. O aumento percentualda área do canal pós preparo apresentou diferença estatisticamente significante apenas no canal mesio-lingual (p=0,023), o desgaste da dentina intraradicular na região voltada para a furca foi estatisticamente diferente somente na raiz distal. Os resultados mostraram que o percentual médio de ocupação da área do canal pelo IAI não apresentou diferença estatística entre os grupos estudados. Concluiu-se que o desgaste da região de cervical com Gates-Glidden e LA Axxxes não influenciou na determinação precisa do diâmetro anatômico apical nos canais de molares inferiores. / The aim of this study was to evaluate, by means of cone beam computed tomography, the transportation, the increased of the area, and the dentine thickness of the cervical third of the root canal of thirty lower first molars prepared with different instruments and the influence of this preparation to determining the initial apical file to bind (IAI), through scanning electron microscopy. The teeth (n = 10) were fixed on three resin plates (samples) according to the instrumentsused in the cervical preflaring and scanned with a cone beam computed tomography device. Then, preparation was performed in the cervical third of the canals: G1 Gattes-Glidden burs #2 and #3 in the mesial canals and #3 and #4 in the distal canal; G2 - LA Axxess #20.06 and #35.06 in the mesial canals and #35.06 and #45.06 in the distal canal. After preparation, the specimens were submitted to a new CT scan. Each canal was sized using manual K-files, starting with size 08 files, until the working length (WL) was reached. File sizes were increased until a binding sensation was felt at the WL, and the instrument sizewas recorded for each canal. The files were fixed with methylcyanacrylate at the WL. Teeth were then sectioned transversally 1 mm from the apex, with the binding file in the position. The apical region was then observed under a scanning electron microscope. The centering ratio showed no statistical difference between groups; the percentage of area increase after preparation showed statistical significance only in the mesio-lingual canal (P = 0.023); the thickness of the dentine in the region facing the furcation showed statistical difference only in the distal root. SEM analysis showed that the mean percentage area of the IAI in relation to the root canal area at the WL showed no statisticalsignificant difference between groups. It was concluded that cervical preflaring with Gates-Glidden or LA Axxess did not influence the determination of the apical gauging in lower molars.

A cirurgia parendodôntica é um recurso utilizado para solucionar casos em que a terapia endodôntica não obteve sucesso, ou ainda na impossibilidade da sua realização. A escolha de um material retroobturador adequado pode contribuir positivamente para o reparo tecidual. Este estudo teve como objetivo avaliar a capacidade seladora de três materiais usados para retroobturação, em dois tempos diferentes, tendo como marcador o corante Rodamina B a 0,2%. Sessenta e seis dentes tiveram as suas coroas seccionadas, os canais preparados com limas manuais e obturados com cimento e guta-percha. Seccionaram-se dois milímetros da porção apical e cavidades retrógradas foram preparadas com pontas de ultra-som lisas; dividindo-se então, em 3 grupos experimentais que receberam os seguintes materiais: MTA Ângelus ® , Real Seal ® e um material experimental desenvolvido pelo IPEN-USP (Instituto de Pesquisas Energéticas e Nucleares da Universidade de São Paulo). Dez elementos de cada grupo foram imersos em soro fisiológico durante 72h a 37°C, antes de serem impermeabilizados e colocados no corante por 24h (grupos I A, II A e III A). Os demais permaneceram 60 dias em soro fisiológico para depois serem impermeabilizados e colocados no marcador (grupos I B, II B e III B). O controle positivo consistiu de 3 espécimes, que não tiveram as cavidades retroobturadas. Outros três espécimes serviram como controle negativo, cada um foi retroobturado com um dos materiais em estudo e foram totalmente impermeabilizados antes de serem imersos no corante. Após o tempo de imersão no corante, todos os espécimes foram lavados, e em seguida, clivados ongitudinalmente no sentido mésio-distal. As superfícies foram avaliadas em lupa estereoscópica com aumento de 20X e fotografadas. A infiltração linear foi medida com auxílio de uma lente reticulada e régua milimetrada. Os resultados foram submetidos aos testes estatísticos de Kruskal-Wallis e verificou-se que não houve diferença entre os grupos do MTA Ângelus ® e do Real Seal ® , sendo que a maior infiltração do corante ocorreu na interface dentina-material experimental, com diferença estatisticamente significante ao nível de 1% (a=0,01). Fazendo a análise estatística de Mann-Whitney entre os grupos com o mesmo material, verificou-se que o tempo de permanência em umidade até 60 dias não influenciou na vedação dos materiais retroobturadores. / Apical surgery is a resource that is used to solve cases in which endodontic therapy was either unsuccessful or could not be done. Choice of root-end filling material contributes for successful. The purpose of this study was to evaluate the sealing ability of three materials used for root-end filling, using 0.2% Rhodamine B. Sixty-six teeth had their crowns removed, and their canals were cleaned and shaped with manual files, and filled with cement and gutta-percha. Two millimeters of the apical portion were sectioned and root-end cavities were prepared in all specimens with smooth ultrasonic tips. Three groups were formed to receive the following materials: MTA Ângelus ® , Real Seal ® , and an experimental material developed by the IPEN-USP (Institute of Energetic and Nuclear Research from São Paulo University). Ten specimens from each group were immersed in a physiological saline solution for 72h at 37°C, before being waterproofed and put in the colorant for 24 h (groups I A, II A, and III A). The others remained in physiological saline solution for 60 days and were then waterproofed and put in the marker (groups I B, II B, and III B). The positive control consisted of three specimens that did not have their cavities root-end filled. Another three specimens served as a negative control, each being root-end filled with one of the materials being studied, and they were totally waterproofed before being immersed in Rhodamine B. After the time of immersion in the colorant, all of the Speci mens were washed and then cleaved longitudinally in the mesio-distal direction. The surfaces were evaluated under a stereoscopic magnifying glass at 20X magnification and photographed. The linear infiltration was measured with a micro metered lens and millimeter rule . The results were submitted to the Kruskal-Wallis statistical tests and it was noticed that there was no difference between the MTA Ângelus ® and Real Seal ® groups. The experimental material presents the most colorant microleakage, with a statistically significant difference (a=0.01). The Mann-Whitney statistical analysis performed in the groups with the same material showed that the period of time the specimen remained exposed to moisture - up to 60 days - did not impact the materials’ sealing capacity.

La membrane plasmique des cellules épithéliales polarisées comporte deux domaines distincts, le domaine apical et le domaine basolatéral. Chaque domaine a une composition en lipides et en protéines déterminée, leur permettant d'assurer des fonctions spécifiques. Les mécanismes moléculaires responsables du tri et de l'adressage des protéines transmembranaires vers le pôle apical sont encore mal connus. La membrane apicale est enrichie en glycosphingolipides et en cholestérol qui forment des microdomaines appelés « rafts ». Expérimentalement, les rafts peuvent être isolés sous forme de DRM (detergent-resistant membranes) définis par leur résistance à un détergent non ionique, le Triton X-100. Il a été proposé que les rafts recrutent les protéines apicales au niveau du réseau trans-golgien et servent de plateforme pour leur adressage au pôle apical. Effectivement les protéines ancrées par le glycosylphosphatidyl-inositol sont résistantes au Triton et sont localisées en général à la membrane apicale. En revanche, la plupart des protéines transmembranaires apicales sont solubles dans le Triton, bien qu'elles soient résistantes à l'action de détergents plus doux comme le Lubrol WX. L'objectif des travaux de thèse a été d'étudier le rôle des rafts dans l'adressage apical de protéines transmembranaires et de comprendre l'effet différentiel du Triton et du Lubrol sur leur solubilisation. Les nucléotides pyrophosphatases NPP1 (basolatérale) et NPP3 (apicale) exprimées de façon stable dans les cellules MDCK ont servi de modèles. NPP3 est insoluble dans le Lubrol et partiellement insoluble dans le Triton, tandis que NPP1 est essentiellement solubilisée. L'étude de la localisation et de la sensibilité aux détergents de mutants et de chimères combinant des domaines cytoplasmiques, transmembranaires et extracellulaires de NPP3 et NPP1, a montré qu'il n'existait pas de corrélation stricte entre l'adressage apical et la résistance aux détergents. La résistance de NPP3 à la solubilisation par le Lubrol est acquise précocement au cours de sa biosynthèse, indépendamment de sa destination finale. Cette résistance dépend d'acides aminés chargés positivement situés dans la queue cytoplasmique, proches de la membrane. Afin de comprendre la sélectivité du Triton et du Lubrol dans l'extraction des protéines et des lipides membranaires, la composition lipidique des DRM obtenus après extraction par le Triton et le Lubrol a été comparée. Les DRM extraits par le Triton et le Lubrol sont enrichis en cholestérol ce qui correspond à la définition des rafts. Cependant, les DRM Triton sont appauvris en lipides du feuillet interne tandis que les DRM Lubrol sont enrichis en phosphatidyléthanolamine. Les DRM Lubrol sont également enrichis en protéines associées au feuillet interne de la membrane. En conclusion, ces travaux montrent que la résistance de la protéine apicale NPP3 à l'extraction par le Lubrol, et en partie par le Triton, est une propriété intrinsèque qui correspond probablement à une adaptation de la protéine à la composition lipidique du domaine apical, mais que cette propriété ne détermine pas son adressage polarisé. De plus, ces travaux montrent que les détergents sont des outils très intéressants pour étudier les interactions entre les protéines et les lipides membranaires, mais qu'il n'existe probablement pas de détergent capable d'isoler de façon stricte des microdomaines membranaires tels que sont définis les rafts. Nos résultats suggèrent que le feuillet interne des rafts est enrichi en phosphatidyléthanolamine et en cholestérol, qu'il est en partie solubilisé par le Triton, ce qui déstabiliserait les protéines transmembranaires et entraînerait leur extraction. Mots clés: détergent, raft, , ciblage apical, cholestérol, microdomaine membranaire, feuillet interne de la membrane, phosphatidyléthanolamine.

La polarité épithéliale est un processus essentiel au cours du développement d'un organisme. Ici, nous nous focalisons sur le tissu épithélial intestinal et épidermal de C. elegans pour comprendre comment la cellule maintient sa polarité en définissant un pôle apical et un pôle basolatéral. Afin d'assurer la mise en place et le maintien de cette polarité, des protéines appelées déterminants de polarité interviennent. Parmi ces déterminants, le module PAR-3/PAR-6/aPKC et CDC-42 sont des acteurs majeurs pour spécifier la polarité apicale. Nous avons montré que le complexe adaptateur pour la clathrine AP-1, un régulateur clé du trafic intracellulaire remplit une fonction inattendue dans ce processus. En effet, nous avons confirmé le rôle d'AP-1 dans le tri basolatéral observé chez les mammifères, mais de façon intéressante nous avons démontré qu'AP-1 contrôle également le tri apical d'une protéine transmembranaire ainsi que la localisation asymétrique apicale de CDC-42 et PAR-6. En effet, l'inhibition d'AP-1 cause une délocalisation basolatérale de CDC-42 et PAR-6. La perte de fonction d'AP-1 induit une conversion de la membrane latérale en membrane apicale et la formation de lumières intestinales ectopiques. La perte de fonction du complexe AP-1 induit également une létalité embryonnaire qui peut s'expliquer par le phénotype identifié dans l'épiderme. Dans cet épithélium, AP-1 contrôle l'intégrité des jonctions cellulaire et notamment le tri apical de la E-cadhérine. Nos résultats démontrent une fonction essentielle d'AP-1 dans le tri apical, directement responsable du maintien de la polarité épithéliale.

The shoot apical meristem (SAM) is the structure that shapes the aerial architecture of the plant, by producing lateral organs throughout development. In the model plant Arabidopsis thaliana, the SAM is always identifiable as a characteristic dome, whether it is found in the centre of a rosette of leaves or at the tip of an inflorescence. When senescence occurs and organogenesis ceases, the now inactive SAM still retains its characteristic appearance and it is never consumed into a terminal structure, such as a flower. Mutant plants that undergo termination represent a valuable tool to understand how the SAM structure and function are maintained during plant life. The aim of this work was to investigate the dynamics of meristem development through morphological and genetic studies of three Arabidopsis mutants that exhibit distinct modes of SAM termination: distorted architecture 1 (dar1), adenosine kinase 1 (adk1) and terminal flower 2 (tfl2). The dar1 mutation is characterised by a severely distorted cellular architecture within the SAM. We propose that dar1 affects the pattern of cell differentiation and/or cell proliferation within the SAM apical dome, resulting in termination by meristem consumption. Instead, the adk1 mutation affects the organogenic potential of the SAM, without altering its structure. The adk1 mutant has increased levels of cytokinins and, as a consequence of this, cell division is enhanced and cell differentiation is prevented in the apex, causing termination by meristem arrest. Finally, tfl2 is mutated in the conserved chromatin remodelling factor HP1, a transcriptional repressor with multiple roles during plant development. The tfl2 SAM terminates by conversion into a floral structure, due to de-repression of floral identity genes. Interestingly, tfl2 mutants also show an altered response to light, an indication that TFL2 might act as a repressor also in the context of light signalling.

Background: Teeth affected by apical periodontitis (AP) that could be retained by root canal therapy (RCT) are increasingly being extracted and replaced with implant-supported crowns (ISC). Objectives: 1) To investigate preferences of dentists and patients towards retaining a tooth with AP using RCT versus its extraction followed by, no replacement, replacement with an ISC, or with a partial fixed or removable denture. 2) To investigate patients’ preferred role and dentists’ ethical responsibilities in decision-making. Methods: A mail-out survey (sent to: dental specialists, n=195, response rate=39%; patients, n=434, response rate=43%) and a web-based survey (general dentist sample, n=304, response rate =15%) were used to collect data. Statistical bivariate and multivariate analyses were undertaken with P set at < 0.05 with Bonferroni adjustment as necessary. Results: RCT or ISC were the most selected treatment choices for dentists, while the preference for RCT was reduced for teeth treated previously with RCT. Dentists’ preferences were associated with their specialty as well as clinical experience in endodontics and/or implant dentistry. Patients’ stated general preference for saving teeth was associated with higher self-rated oral health, frequent dental check-ups, and higher socio-demographic factors. Those with higher education, regular dental visits and previous experience of RCT preferred to undergo RCT for future treatment in comparison to those who never experienced RCT. Patients preferred a collaborative role with their dentists in making treatment decisions and valued the retention of natural teeth very highly. They also felt that communication with and trust in their dentist was paramount. Conclusion: Dentists should establish rapport with patients in a milieu that values and respects the patients’ autonomy. By following the highest standards of evidence-based care, and transferring unbiased information on treatment options and associated risks/benefits, it is highly probable that dental care will be delivered in a more ethical manner than would otherwise be possible.

Background: Teeth affected by apical periodontitis (AP) that could be retained by root canal therapy (RCT) are increasingly being extracted and replaced with implant-supported crowns (ISC). Objectives: 1) To investigate preferences of dentists and patients towards retaining a tooth with AP using RCT versus its extraction followed by, no replacement, replacement with an ISC, or with a partial fixed or removable denture. 2) To investigate patients’ preferred role and dentists’ ethical responsibilities in decision-making. Methods: A mail-out survey (sent to: dental specialists, n=195, response rate=39%; patients, n=434, response rate=43%) and a web-based survey (general dentist sample, n=304, response rate =15%) were used to collect data. Statistical bivariate and multivariate analyses were undertaken with P set at < 0.05 with Bonferroni adjustment as necessary. Results: RCT or ISC were the most selected treatment choices for dentists, while the preference for RCT was reduced for teeth treated previously with RCT. Dentists’ preferences were associated with their specialty as well as clinical experience in endodontics and/or implant dentistry. Patients’ stated general preference for saving teeth was associated with higher self-rated oral health, frequent dental check-ups, and higher socio-demographic factors. Those with higher education, regular dental visits and previous experience of RCT preferred to undergo RCT for future treatment in comparison to those who never experienced RCT. Patients preferred a collaborative role with their dentists in making treatment decisions and valued the retention of natural teeth very highly. They also felt that communication with and trust in their dentist was paramount. Conclusion: Dentists should establish rapport with patients in a milieu that values and respects the patients’ autonomy. By following the highest standards of evidence-based care, and transferring unbiased information on treatment options and associated risks/benefits, it is highly probable that dental care will be delivered in a more ethical manner than would otherwise be possible.