Primero Enamel: versatile, chipresistant, low hardness
Primero Enamel is build-up of three different glasscomponents that combined provide a robust chip-resistance and a low surface hardness. The first is a high melting glasscomponent containing leucite crystals, which act as stressbreakers and provide chip-resistance. The second glasscomponent is opalescent and the third a low-melting glasscomponent, that causes a hydrothermal surface gelation. The leucite crystalline content increases the load bearing capacity during chewing and makes Primero Enamel porcelain chip-resistant. The low surface hardness is obtained by an exchange reaction with saliva, which creates a water-rich and soft surface layer, with a hardness similar to natural enamel (HV 450-470). Opalescence is the optical effect of blue absorption, causing an orange tinge, when light is passing through. When light falls on the tooth against a dark background we can see that blue is absorbed.
Primero Enamel has a strong opalescense through the presense of very fine calciumphosphate crystals
Primero Enamel has a structure consisting of three glas component, of which one contains Leucite crystals. in fysical and clinical testing the chipresistance of Primero Enamel was clearly proven. The photo shows a bridge that broke at a n average load of 144 kg after 1,2 million loading with 5 kg, without showing any chipping (Foto: Klinikum der Universität Regensburg).
Low surface hardness
The surface of Primero Enamel reacts with saliva bij exchanging sodium in the porcelain for watermolecules from saliva. This “hydrothermal” reaction gives a soft surface layer with a hardness of 450-475, very close to the hardness of natural enamel.
Primero Enamel has a natural fluorescense.
Porcelain adhesion with zirconia
The adhesion of Primero Enamel porcelain with zirconia is based on excellent wetting and an oxygen bridge with zirconia. The photo shows that a crack initiated at porcelain-zirconia interface remains in the porcelain. This is what we call an cohesive failure instead of an adhesive failure.
Reflection of light in fullzirconia and Primero
Because zirconia has a refractive index close to that of diamond and porcelain has a refractive index close to natural enamel we can see a difference in the flow of light through the restoration. In full zirconia restorations the reflection is superficial, while translucent porcelain layer gives a natural reflection on the zirconia with a color that appears “to come from the inside“.