Avaliação da resistencia da união composito/dentina ao cisalhamento em dentes deciduos submetidos ao tratamento com hipoclorito de sodio

Orientador: Regina Maria Puppin-RontaniDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de PiracicabaResumo: O objetivo deste estudo foi avaliar diferentes sistemas de união (Single Bond - SB, Prime & Bond 2.1 - PB e Clearfil SE Bond - CSEB), aplicados à dentina de dentes decíduos, submetida ou não ao tratamento prévio com hipoclorito de sódio (NaDCI), através da análise da resistência da união ao cisalhamento (RC) e do aspecto morfológico da união compósito/dentina. Foram selecionados 45 molares decíduos hígidos extraídos. As raízes dos dentes foram seccionadas na junção cemento-esmalte e as coroas ao meio, no sentido mésiodistal. As amostras foram então embutidas com resina de poliestireno em tubos de PV.C., com a superfície vestibular, lingual ou palatina externamente e lixadas até a obtenção de uma superfície plana em dentina (3 mm de diâmetro). A seguir, foram aleatoriamente distribuídas em 6 grupos (n=15), sendo: G1 - aplicação do sistema SB; G2 - condicionamento ácido (CA), aplicação de NaOCI seguida pelo sistema SB; G3 - aplicação do sistema PB; G4 - CA, aplicação do NaOCI seguida pelo sistema PB; G5 - aplicação do sistema CSEB e G6 - aplicação de NaOCI, seguida pelo CSEB. Todos os sistemas de união foram aplicados de acordo com as instruções dos fabricantes. O NaOCI a 10%foi aplicado nos grupos 2,4 (após o condicionamento ácido) e 6 (antes da aplicação do sistema de união) por 60s, e o dente foi lavado por 30s e seco com papel absorvente. Em seguida, o compósito Filtek Z-250 foi inserido em três incrementos (aproximadamente 2 mm), em uma matriz bipartida de silicone por adição adaptada a um posicionador metálico, e fotoativado por 20s cada incremento. As amostras foram armazenadas em água destilada a 37°C por 24h e então submetidas ao ensaio de cisalhamento em uma Máquina de Ensaio Universal (Instron - modelo 4411) à velocidade de 0,5mm/min. Os padrões de fratura foram observados em microscópio estereoscópico (aumento 25X), e os representativos de cada grupo foram observados em Microscopia Eletrônica de Varredura (MEV). Para a análise da união compósito/dentina foram utilizados três dentes para cada grupo e repetidos todos os procedimentos descritos anteriormente. Emseguida, foram seccionados no centro da restauração e preparados para observação em MEV. Os dados obtidos no ensaio de cisalhamento foram submetidos à análise de variância e teste de Tukey (p<0,05). Os valores obtidos em MPa foram: G1- 3,17 :t 1,97; G2 - 2,93 :t 1,36; G3 - 2,04 :t 0,27; G4 - 1,91 :t 0,74; G5 - 2,67 :t 1,22; G6 -2,14 :t 1,10. De acordo com os resultados, pôde-se observar que houve diferença estatística significativa (p<0,05) entre os materiais (SB-CSEB-PB). Não houve diferença estatística significativa entre os grupos com ou sem tratamento do substrato, independente do material utilizado (p>0,05). O tipo de falha freqüentemente observada em todos os grupos foi a falha mista (coesiva no compósito + adesiva). Com relação ao aspecto . morfológico da união, nas amostras sem tratamento do substrato foi observada a presença da camada híbrida e dos prolongamentos resinosos. Nas amostras com tratamento da superfície (com NaOCI) não foi observada a presença da camada híbrida, porém foram observados prolongamentos resinosos. Pôde-se concluir que o tratamento da superfície com hipoclorito de sódio não afetou a resistência da união compósito/dentina ao cisalhamento, porém, interferiu na formação da camada híbrida, em dentes decíduosAbstract: The aim of this study was to evaluate different bonding agents (Single Bond - SB, Prime & Bond 2.1 - PB e Clearfil SE Bond - CSEB), in primary teeth treated with sodium hypochlorite (NaOCI) on the shear bond strength (SBS) and micromorphology of the resin/dentin interface. Forty-five sound extracted primary molars were selected. The roots were sectioned in the enamel-cement junction and the crowns longitudinally, in the mesio-distal sense. The samples were embedded in polystyrene resin with the bucal, lingual or palatine surface externally and they were flattened until dentin surface was reached (3mm in diameter). Then, the samples were randomly assigned in 6 groups (n=15), and received the following treatments: G1 - SB; G2 - acid etching (AE), 10% NaOCI and the SB; G3 - PB; G4 - AE, 10% NaOCI and the PB; G5 - CSEB; G6 - 10% NaOCI followed by CSEB. Ali the adhesive systems were applied according to manufactures' instructions. The 10% NaOCI solution was applied for 60s in groups 2,4 (after acid etching), and 6 (before adhesive system), washed for 30s and dried with tissue paper. Next, the composite resin was inserted in increments (2mm) in a vinyl polysiloxane impression material matrix, adapted in a metallic holder, and light cured for 20s (each increment). The samples were stored in distilled water at 37°C for 24h and then, submitted to SBS test in a universal testing machine (Instron - model 4411) with a crosshead speed of 0.5mm/min. The failure sites were observed in stereoscope microscopy of 40X magnification, and the representative failures of each group were observed in Scanning Electron Microscopy (SEM). The results obtained were submitted to ANOVA and Tukey's tests (p<0.05). The values in MPa were: G1- 3.17 :t 1.97;G2 - 2.93:t 1.36;G3 - 2.04:t 0.27; G4- 1.91 :t 0.74; G5 - 2.67:t 1.2; G6 -2.4:t 1.0. According to the results, it could be noticed that there was a statistical significant difference (p0.05) among ali the groups with or without treatment of the substrate, independently of the material used. The mixed fail (cohesive in resin + adhesive) was the one most frequently observed in ali groups. Regarding the interface aspect in specimens without substrate treatment (NaDCI) it could be observed the presence of the hybrid layer and resin tags whereas treated specimens only resin tags could be observed. It could be concluded that the treatment of the dentin surface with sodium hypochlorite did not affect the resin/dentin bonding strength but interfered in the hybrid layer formation in primary teethMestradoMestre em Materiais Dentário

Influence of the conditioning technique of a lithium disilicate vitroceramic

Introduction: Lithium disilicate reinforced glass ceramics are materials that require good adhesion to ensure clinical success. Objective: To evaluate the bond strength of resin cements to lithium-disilicateenhanced vitroceramics using different cleaning techniques of recently conditioned ceramics. Material and methods: Twelve ceramic discs (IPS Empress II) were made and inserted into PVC pipes using acrylic resin. The ceramic surface was designed and submitted to a 10% hydrofluoric acid conditioning process for 20s. Then, the specimenswere divided into 3 groups (n = 16) according to the cleaning techniques of recently conditioned ceramics: 1) control - conventional technique (no cleaning after the conditioning process); 2) application of 37% phosphoric acid for 20s; 3) 90% ethyl alcohol bath in a ultrasound tub for 4 min. After cleaning, the silane agent was applied for 1 minute and silicon matrices (1 mm in diameter x 1 mm in height) were made for further application of the resin cement (Vitique, DMG), which was handled according to the manufacturer’s instructions. Four cylinders were prepared on each ceramic surface. The specimens were storedin distilled water for 48 hours and subjected to the micro-shear test in a universal testing machine. After the micro-shear test, a failure analysis of the specimens was performed. Data were submitted to ANOVA (analysis of variance for a criterion) with a significance level of 5%. Results: There was no significant difference between groups (p > 0.05). Conclusion: the cleaning technique of the recently conditioned ceramics does not interfere with the resin/cement bond strength valuesIntroduction: Lithium disilicate reinforced glass ceramics are materials that require good adhesion to ensure clinical success. Objective: To evaluate the bond strength of resin cements to lithium-disilicateenhanced vitroceramics using different cleaning techniques of recently conditioned ceramics. Material and methods: Twelve ceramic discs (IPS Empress II) were made and inserted into PVC pipes using acrylic resin. The ceramic surface was designed and submitted to a 10% hydrofluoric acid conditioning process for 20s. Then, the specimenswere divided into 3 groups (n = 16) according to the cleaning techniques of recently conditioned ceramics: 1) control - conventional technique (no cleaning after the conditioning process); 2) application of 37% phosphoric acid for 20s; 3) 90% ethyl alcohol bath in a ultrasound tub for 4 min. After cleaning, the silane agent was applied for 1 minute and silicon matrices (1 mm in diameter x 1 mm in height) were made for further application of the resin cement (Vitique, DMG), which was handled according to the manufacturer’s instructions. Four cylinders were prepared on each ceramic surface. The specimens were storedin distilled water for 48 hours and subjected to the micro-shear test in a universal testing machine. After the micro-shear test, a failure analysis of the specimens was performed. Data were submitted to ANOVA (analysis of variance for a criterion) with a significance level of 5%. Results: There was no significant difference between groups (p > 0.05). Conclusion: the cleaning technique of the recently conditioned ceramics does not interfere with the resin/cement bond strength value

Prevalence of TMD and its impact on quality of life in male construction workers / Prevalência de DTM e impacto na qualidade de vida de trabalhadores na construção civil

Background: Temporomandibular joint disorder (TMD) can significantly affect the quality of life of individuals. However, evidence of TMD involvement and the extent of the impacts caused by it, in groups exposed to a stressful routine, are still scarce. Therefore, the aim of the present study was to evaluate the prevalence of TMD signs and symptoms and their impact on quality of life related to oral health in construction workers. Material and methods: This cross-sectional study included only male individuals. Illiterate workers and functional illiterate were excluded. The diagnosis of TMD was established according to the Research Diagnostic Criteria for TMD (RDC/TMD). The Oral Health Impact Profile questionnaire validated for Portuguese (OHIP-14) was used to assess the impact of TMD on oral health and quality of life. Descriptive analysis of TMD signs and symptoms was performed. Data related to the OHIP-14 questionnaire were compared using the Mann-Whitney U test. Pearson's correlation was also performed. The established alpha of this study was 5%. Results: 230 individuals were included. The mean age was 37.8 (SD=11) years. The most frequent TMD sign and the symptom was disc displacement, 86 (37.39%) of the individuals. OHIP-14 demonstrated a statistically significant difference when compared to all TMD signs and symptoms (p&lt;0.001). A weak correlation was observed between pain and OHIP-14 (r=0.366; p&lt;0.0001). Conclusion: TMD affects oral health and quality of life for construction workers