CDE0211

38 I I industry report _ IPS e.max Press _The dental laboratory industry has searched for a material that is structurally sound and highly aesthetic. This material is now available in lithium-disilicate glass ceramic (IPS e.max Press, Ivoclar Vivadent), which is a material like no other in dentistry. The IPS e.max Press lithium disilicate is the first structural (long-lasting) material that is aesthetic, even without layering, when its High Translucency ingots are used. Its high strength comes from the lithium-disili- cate crystals. The IPS e.max lithium disilicate is composed of quartz, lithium dioxide, phosphoric oxide, alumina, potassium oxide and other com- ponents. Overall, this composition yields a glass ceramic that shows low thermal expansion when it is processed. Polyvalent ions dissolved in the glass provide thedesiredcolourofthelithium-disilicatematerial. These colour-releasing ions are homogeneously distributedinthesingle-phasematerial,resultingin the elimination of colour pigment imperfections in the microstructure. With its four levels of opacity and translucency —High Opacity, Medium Opacity, Low Translucency and High Translucency—IPS e.max Press enables laboratory ceramists to satisfy different aesthetic demandsanddeliverabeautifulandstrongrestora- tion. Overall, these materials demonstrate specific advantages, such as higher edge strength versus traditional glass-ceramic materials (can be finished more thinly without chipping); the low viscosity of the heated ingot, which enables pressing to very thin dimension (enabling minimal preparation or no-preparation veneers); and a chameleon effect owing to higher translucency. In some cases, mini- mal tooth preparation is needed (for example, thin veneers) and IPS e.max lithium disilicate enables restorations to be pressed as thin as 0.3 mm, while still ensuring strength of 400 MPa. This article guides readers through the process of accurately maintaining the incisal edge posi- tion, length, shape and contour of provisional restorations when fabricating final IPS e.max Press anterior restorations. Additionally, if one were to cosmeticdentistry 2_2011 Figs. 1 & 2_Pre-op 1:2 view showing discoloured temporary repairs to the central incisors. Fig. 3_An approved model of the provisional restorations was perfected by adding wax and reducing stone. Fig. 4_The facial incisal area was bevelled back 0.5 mm using a contour stone. One step closer to nature: Imitating natural optical properties using lithium-disilicate restorations Author_ Dr Bradley L. Jones, USA Fig. 2 Fig. 1 Fig. 4Fig. 3