This study evaluated the influence of curing tip distance, shade and filler particle size on Vickers microhardness (VHN) of composite resins. Two composites were tested: Filtek Z250 microhybrid (3M ESPE; shades A1 and A3.5) and Filtek Supreme nanofilled (3M ESPE; shades A1B and A3.5B). For each resin, 42 specimens (5 mm in diameter and 2 mm height) were prepared being 21 for each shade. The specimens were exposed using a 20-second exposure to a quartz-tungsten-halogen light source with an irradiance of approximately 560 mW/cm2, at the following distances: 0 mm (surface contact), 6 mm and 12 mm from composite surface. Effectiveness of cure of different resins, shades and curing distances was determined by measuring the top and bottom hardness (VHN) of specimens using a digital microhardness tester (load: 50 g; dwell time: 45 seconds) 24 hours following curing. The hardness ratio was calculated by dividing VHN of the bottom surface by VHN of top surface. Three-way ANOVA and Tukey's post-hoc test (p<0.05) revealed statistically significant differences for all analyzed factors. As for top hardness, as microhardness ratio (bottom/top), the factors shade, distance and composite filler particle size exerted influence on resin curing. Lighter shade composites (A1 and A1B) showed higher hardness values. At 6 and 12 mm curing tip distances, hardness was lower when compared to 0 mm. The microhybrid composite resin presented higheer hardness, being its microhardness ratio satisfactory only at 0 mm for both shades and at 6 mm for the lighter shade. The nanofilled composite resin did not present satisfactory microhardness at the bottom while the microhybrid composite resin had higher hardness than the nanofilled. Composite's curing tip distance and shade can influence hardness.

This study evaluated the influence of the dental substrates obtained after the use of different caries removal techniques on bonding of a self-etching system. Forty, extracted, carious, human molars were ground to expose flat surfaces containing caries-infected dentine surrounded by sound dentine. The caries lesions of the specimens were removed or not (control--G1) either by round steel burs and water-cooled, low speed, handpiece (G2), or by irradiation with an erbium, chromium:yttrium scandium gallium garnet (Er,Cr:YSGG) laser (2W, 20 Hz, 35.38 J/cm(2), fiber G4 handpiece with 0.2826 mm(2), non-contact mode at a 2 mm distance, 70% air/20% water--G3) or using a chemo-mechanical method (Carisolv--G4). Caries-infected, caries-affected and sound dentines were submitted to a bonding system followed by construction of a resin-based composite crown. Hour-glass shaped samples were obtained and submitted to a micro-tensile bond test. The bond strength data were compared by analysis of variance (ANOVA), complemented by Tukey's test (P

À Deus, que me guia, protege e acompanha sempre. À minha orientadora, Prof a. Dr a. Adriana Bona Matos, pela confiança depositada e a oportunidade de compartilhar de seus conhecimentos. Sua incansável e sábia orientação e apoio em todos os momentos foi essencial para a realização deste trabalho. À Prof a. Dr a. Júlia Maria Pavan Soler, do IME-USP, pela ajuda na análise e interpretação estatística. À Prof a. Dr a. Márcia Martins Marques, pela confiança e todo apoio neste período. Ao Prof. Dr. Antônio Alberto de Cara, que me incentivou a dar os primeiro passos na Dentística. Agradeço por todo seu apoio e amizade durante todos estes anos. Aos professores do Departamento, por todo conhecimento compartilhado. Aos funcionários do Departamento, especialmente Soninha, Davi, Neuza, Ana e Arnaldo por todo auxílio e atenção. Aos meus colegas da Dentística Restauradora II, pela convivência, estímulo e momentos alegres. Ao colega Tiago Zanet, pelo auxílio com as radiografias digitais. Aos colegas do Curso de Pós-Graduação em Dentística, pela amizade e companheirismo. À Vânia, Glauci, Solange e Rita, funcionárias da biblioteca da FOUSP, pelo auxílio na revisão e formatação do texto. Às funcionárias do serviço de Pós-Graduação da FOUSP, pela atenção, paciência e competência em todos os momentos. Palavras-chave: Adesão-Dentina infectada-Dentina afetada por cárie-Adesivo auto-condicionante-Resistência adesiva-Micro-tração Tachibana A. Microtensile bond strength of self-etching adhesives to caries-affected dentine [Dissertação de Mestrado].

<p><strong> </strong></p><p>Objective:<strong> </strong>The aim of this study was to detect the influence of application mode of cleansing agents, on enamel and dentin during the adhesion process of a one-step adhesive system.</p><p>Materials and Methods: 24 human molars were sectioned into halves along the long axis for enamel and dentin tests. The cleansing agents used were hydrogen peroxide, anionic detergent, and antiseptic solution. In the experiment, these agents were applied with and without friction on enamel and dentin surfaces. A one-step adhesive system (Clearfil S3 Bond) was applied on dental surface and composite resin cylinders were built using Tygon tubing molds. After 24 h, μSBS test (1 mm/ min) and fracture analysis were performed. Results: There was no statistically significant difference in bond strength values regarding the application mode of cleansing agents for enamel and dentin (p≥0,05).</p><p>Conclusions: Regarding bond strength, application mode of the cleansing agents used in this study presented the same behavior. </p><p> </p>