ROXANA BUZATU, ANCA S. VALCEANU, ADELINA GRIGORE, CAMELIA SZUHANEK THE EVALUATION OF THE BIOBLEACH TRAYS EFFICIENCY AND MANUFACTURING PROCESS Tooth bleaching and other cosmetic treatments (performed at home or in the dental office) are very common nowadays. The use of thermoplastic materials for the manufacturing of whitening trays should have good biomechanical properties in order to assure a good treatment outcome with a good esthetic result. The most common tray manufacturing material is an acrylic poly-resin thin foil that can be vacuum-formed in order to fit any clinical situation. The material must be inert in order to prevent harmful free radicals release form the interaction with different bleaching substances. Thermoformed trays were manufactured in our dental office and immersed in a mixed oral suspension (that also contained artificial saliva) in order to test the behavior of the material in the intraoral environment.