Cavalheiro, AlexandreSilva, Ana LuísaDias, Madalena de Quinhones Levy Rosa2016-12-282016-12-2820142014http://hdl.handle.net/10451/25476Tese de mestrado, Medicina Dentária, Universidade de Lisboa, Faculdade de Medicina Dentária, 2014A new generation of one-bottle self-etch dental adhesives is currently being used. The literature refers to them as universal or multi-mode adhesives. Universal adhesives are indicated as either self-etching or etch-and-rinse adhesives. Some clinical studies and laboratory evaluations have been performed, in fact, demonstrating that some universal adhesives may perform at the same level of previous adhesives. Purpose: To evaluate the effect of an additional hydrophobic resin layer (Adper Scotchbond Multipurpose) on the resin-dentin bond strength (_TBS), of the universal adhesive Scotchbond Universal used in a self-etch mode compared to the manufacturer’s instructions. Materials and Methods: A total of six extracted human teeth (n=6) were randomly distributed between two groups for bond strength testing, according to the different adhesive strategy used: Scotchbond Universal applied as a one-step self-etch adhesive as per manufacturer’s instructions (SBU SE D) and Scotchbond Universal applied as a one-step self-etch adhesive followed by one layer of the hydrophobic resin Adper Scotchbond Multipurpose. After composite restoration, specimens composed of sticks with 1mm2 were stored in distilled water (37ºC/24h) and then tested at 1mm/min using micro-tensile tests (_TBS) to assess dentin bond strength. Failure modes were analyzed under a stereomicroscope. Data were analyzed with a parametric pairedsample t-test since the assumptions of normality were valid. Results: For dentin, the use of a hydrophobic resin layer (SBU+A SE D) resulted in a statistically significantly higher mean μTBS value (38,59 ± 22,21 MPa) than the SBU SE D group (27,66 ± 13,22 MPa), (p<0,05) with a 95% confidence interval. Conclusions: Within the limitations of this in vitro study, it can be concluded that the use of a hydrophobic resin layer may be beneficial to the resin-dentin bond strength when applied to dentin with the self-etch mode. Keywords: universal adhesives; self-etch; hydrophobic resin coat; micro-tensile bond strength.engMateriais dentários - adesivosTeses de mestrado - 2014master thesis201269120