Samples of group «A» were made up with Lucitone 199 acrylic Dentsply International Milford Delaware, this group did not have metallic inserts. Samples of group «B» were made up with Lucitone 199 acrylic Dentaurum, Pforzheim, Germany, this group did have metallic insert. Samples of group «C» were made up with ProBase Hot acrylic Ivoclar Schaan Liechstenstein without metallic inserts. Samples of group «D» were made up with ProBase Hot acrylic with metallic inserts.
El grupo «A» fue de acrílico Lucitene 199 Dentsply International Milford Delaware sin inserto metálico, el grupo «B» de acrílico Lucitone 199 con inserto metálico Dentaurum, Pforzheim, Germany, el grupo «C» de acrílico ProBase Hot Ivoclar Schaan Liechtenstein sin inserto metálico y el grupo «D» de acrílico ProBase Hot con inserto metálico.