The aim of this study is to evaluate the interference of different types of rotary cutting instruments used in dental preparation on the interaction morphology and effectiveness of self-adhesive resin cements to dentin. For this, sixty-two human molars will be sectioned, about 1mm below the dentin-enamel junction and then the occlusal enamel of the remaining coronal portion removed to expose a flat of dentin. The exposed dentin will be prepared using a rotary cutting instruments as follows: diamond bur - PD 1090, KG SORENSEN - medium granulation, with particle size ranging from 91-126¼m; diamond bur- PD KG SORENSEN 3101F - with fine-grained 46¼m particles of diamond and tungsten carbide bur - BC 56 KG SORENSEN, with 6 blades. It will also be used as a control, the Silicon Carbide Sandpaper - 600 Grit. After the dentin preparation and creation of the smear layer, the prepared surfaces shall be submitted to the interaction with one of the following self-adhesive resin cements: RelyX U100 (3M ESPE) or Clearfil SA Luting (Kuraray Medical). The results of this interaction will be evaluated by means of micromorphological investigation using Scanning Electron Microscopy (SEM) in order characterize the level of dentin surface morphology alterations and the cement/dentin bonding interface. In addition, the microtensile bond strength test will be performed and the fracture modes obtained classified. The authors expect that development of this work can provide important new information, since the literature doesn´t have previous studies that exanimate the interference of different types of rotary cutting instruments used for the cavity preparation on the effectiveness of self-adhesive cements to dentin. As this category of resin cement employee a particular strategy for bonding, which depends on contact with the dental tissues, it is speculated that smear layers with different characteristics may affect the form of interaction with the dentin.
News published in Agência FAPESP Newsletter about the scholarship: