In the dental surgery, the impression is washed and then put in a bag but not wrapped in a moist paper towel. The residual moisture which will preserve the impression.
Once the identification sheet has been completed, the impression can be immersed in a pre-disinfection solution for about 3 minutes. Compressed air can be used to remove any excess water. The impression is then ready for pouring. We recommend the use of GC Fujirock dental stone, in accordance with the manufacturer's instructions. First the operator pours plaster onto the preparation, and after it has set the second pouring is reserved for the opposing arch. The product has low permanent deformation, 0.12% at 24 hours and 0.3% at 48 hours, which allows enough time for processing in the laboratory. Taking the impression off the stone model is simpler and the integrity of the model is preserved.
For crown and bridge work, an impression taken with Apol Classe alginate is treated by the same technical processes as a silicone impression. Apol Classe used in a dual arch tray impression gives very accurate reproduction of occlusion. The perfect compatibility between Apol Classe and dental stone is characterised by a powerful hydrophilic force, unlike silicone which by contrast tends to repel dental stone. The alginate formulation is by nature hydrophilic and when combined with the accuracy of the material, this results in an accurate model with a remarkable surface condition.
In this case the preparation is modelled by CADCAM; the screen shows a representation of the future zirconium crown. The definitive crown is ready to be tried in the mouth.
Apol, Dental Product Manufacturer, 597 rue René Cassin - 39 300 Champagnole - France. With kind participation of "laboratoire Actuel Dental" from Evreux (F)
