aim: Discolouration of direct composite resin restoration poses a significant aesthetic problem. This study compares the staining capacities of various beverages on direct composite materials, and compares the stain removing abilities of in-office bleaching using 38% Hydrogen Peroxide (Opalescence Boost) and re-polishing with Sof-Lex polishing system (3M ESPE). Materials & Methods: 180 composit...

PURPOSE The aim of this study was to evaluate the surface hardness of six composite resins: Revolution, Natural Flow, Fill Magic Flow, Flow-it! (flowables), Silux Plus (microfilled) and Z100 (minifilled) before and after polishing at different times. MATERIALS AND METHODS For this purpose, 240 specimens (5mm diameter, 1.4mm high) were prepared. Vickers hardness was determined before and after...

Although computer controlled polishing (CCP) of aspheres and freeforms is one of the best understood state-of-the-art fab processes today, there are yet some unsolved issues: e.g. compared to bonnet polishing, fluid jet polishing is taking less iteration steps reaching the same form accuracy and ion beam figuring eventually is reaching much higher shape accuracies. This paper is a first move in...

Non-water based fixed abrasive polishing was adopted to manufacture LBO crystal for nano precision surface quality because of its deliquescent. Ethyl alcohol was selected as the non-water based slurry solvent and ethanediamine, lactic acid, hydrogen peroxide was added in the slurry as a chemical additive, respectively. Effect of different additives with non-water based slurry on material remova...

The specification for the total thickness variation (TTV) of the device layers on thick-film silicon on insulator (SOI) wafers tighten for future applications. Therefore, the bulk removal polishing process of current technology after grinding cannot meet the demands in terms of flatness. The currently required amount of material removal for polishing out the induced sub surface damage (SSD) of ...

For time and cost saving reasons, the lowest surface roughness possible is sought in milling operations. High speed milling is recommended in order to minimise the amount of material to be removed in subsequent finishing operations, e.g. grinding, electrical discharge machining or manual polishing. Several roughness parameters are usually employed for the characterization of polished surfaces. ...

UNLABELLED Esthetics and durability of materials used to fabricate artificial eyes has been an important issue since artificial eyes are essential to restore esthetics and function, protect the remaining tissues and help with patients' psychological therapy. However, these materials are submitted to degrading effects of environmental agents on the physical properties of the acrylic resin. OBJ...

The widespread use of aesthetic f illings has highlighted their advantages and disadvantages. One of the most troublesome features of earlier aesthetic materials was the difficulty of finishing the restoration surface to decrease adherence of food debris. The rougher the finished surface, the greater the possibility of bacterial accumulation and discolouration of restoration along the restorati...

Polishing can be more uniform if the polishing path provides uniform coverage of the surface. It is known that Peano paths can provide uniform coverage of planar surfaces. Peano paths also contain short path segments and turns: (1) all path segments have the same length, (2) path segments are mutually orthogonal at the turns, and (3) path segments and turns are uniformity distributed over the d...