Live WebinarImmediacy and bone maintenance in the long term: Neodent Philosophy.
25 Feb 2021, 09:00 PM Dubai
Dr. Sérgio R. Bernardes
Press technology is considered an efficient and reliable method to manufacture all-ceramic restorations. The IPS e.max Press (Ivoclar Vivadent) all-ceramic system enables highly aesthetic restorations that functionally and aesthetically integrate so well that they are nearly indistinguishable from the natural dentition. Now the IPS e.max Press range has been extended to include five new shades. The writer covers some essential principles in the first part and presents the application of these principles in the second part on the basis of a clinical case.
Dental technicians look at new materials with a cautious and critical mind. With our well-trained eye, we in particular scrutinise the light optical properties of any newly launched all-ceramic product. Recently, interesting new materials have been introduced with the extension of the IPS e.max Press portfolio (Ivoclar Vivadent). Five new shades (MT A3.5, B2, C1, C2, D2) have been added to the medium translucency MT range of the IPS e.max Press ingots to give technicians even more options to imitate the large diversity of characteristics found in the natural dentition. The approach that best matches the given indication can be conveniently selected, whether this is a full-contour restoration customised with the staining technique or a cut-back with microlayering.
Three benefits of IPS e.max Press for laboratories
Three benefits of IPS e.max Press for clinicians
The role of brightness and translucency in achieving shade harmony
In addition to manual skills and functional knowledge, dental technicians should know the basic optical properties of natural teeth and ceramic materials when using the ceramic press technique. Translucency is one of the distinguishing features of the IPS e.max Press ingots. The level of translucency (low, medium, high) is selected in relation to the patient’s oral situation (target tooth shade, shade of the preparation). The restoration is finished using either a staining or layering technique. Whichever method is preferred, choosing the “correct” ingot is essential to achieving a successful outcome. The choice of ingot has a significant effect on the result. Monochromatic lithium disilicate ingots in the medium translucency (MT) range bridge the gap between HT and LT ingots. MT ingots are suited for cases where the brightness of an HT restoration would be clearly too low. Given their reduced chroma, the MT ingots offer room for creativity to provide patient-specific customisations. These bright MT ingots are now available in nine A–D and three BL shades. The IPS e.max Press system has only just become even more attractive.
MT ingots: advantages and possibilities
MT ingots are mainly used for aesthetic restorations that are expected to offer a lifelike translucency and high level of brightness. A few highlights of the material include:
Allocating the MT ingots on the A–D scale (of brightness)
The portfolio of IPS e.max Press MT ingots has now been extended to include five additional shades. It is necessary to create a common understanding of what the term “value” means before positioning the MT ingot in the IPS e.max portfolio.
There are three properties that come into play when determining the shade of a tooth: basic colour (hue), intensity (chroma) and lightness (value). “Value” describes the amount of light reflected back from an object. This way of seeing colour is based on the Munsell system, one of the most widespread colour order systems. The Munsell system describes “value” on a scale from white to grey/black. Objects with a high brightness value contain less grey and appear lighter, while objects with a low brightness value contain more grey and look darker. Lowering the value means that the amount of light reflected from the object is decreased and the remaining light is absorbed or scattered elsewhere.
The MT ingots are indicated for restorations that require:
Given their reduced chroma, the MT ingots offer room for creativity to individualize restorations and achieve a natural-looking transition between dentin and enamel (Figs. 2a–d).
Position of the MT ingot in the BL (bleach) range
The MT ingots are additionally available in bleach shades (BL). The MT ingots of the bleach range offer ample scope for creativity in the production of natural-looking restorations because they feature a balanced relationship between value, chroma and translucency and their chroma is based on different intensities of white (by contrast, A–D shades exhibit varying intensities of yellow) (Fig. 3). Smooth transitions between dentin and enamel can be achieved with both the staining technique and the cut-back/microlayering technique. Figures 4a–b show the bleach ingots in order from the highest to the lowest value.
The MT bleach ingots are suited for restorations in bleach shades that require:
“Recipe” for choosing the correct ingot
Success in the press technique largely hinges on selecting the right ingot. By considering some basic principles and following a consistent approach, the best ingot for the given clinical situation can be found. Four aspects come into play:
a) Expectations of the patient
If the restorations should be adapted to blend in with the neighbouring dentition, the layering technique is best used. If the patient wants to have a “brighter smile”, the focus will be on the bright ingots (IPS e.max MT or LT). Depending on the clinical situation, pressed restorations can be completed using the staining technique or the microlayering technique.
b) Design and depth of preparation
If the preparation is confined to superficial enamel (0.3 to 0.5 mm), the HT ingot is a good choice. If the preparation extends into the deeper strata of the enamel (0.7 to 0.8 mm), the MT ingot provides a better choice. The MT ingot features enamel-like optical properties and a balanced relationship between brightness and translucency. If the preparation extends into the dentin, a low translucency (LT) ingot is indicated as this is the ingot that looks the most like dentin.
c) Tooth shade and shade of the prepared tooth
Depending on the difference between the shade of the tooth and the preparation, a HT ingot may appear to provide the best choice (depending on the depth of the preparation). However, HT ingots do not provide sufficient brightness to conceal, e.g., a dark preparation. In this case, the alternative is to use an MT ingot.
d) Technique employed to complete the restoration
The translucency of the neighbouring natural dentition has an effect on the technique used to complete the pressed restoration, i.e. either by staining technique (IPS Ivocolor) or by cut-back and layering technique (IPS e.max Ceram). Macrophotography provides an easy way to establish if a low, medium or high translucency is required. In the case of high translucency, the recommended approach is to use the layering technique for the entire restoration or a cut-back combined with a veneering ceramic to reproduce the features (e.g. translucency, transparency, opalescence) of the natural neighbouring teeth. If the right materials are used, it is in some cases possible to use the staining technique to emulate the appearance of natural enamel.
The second part of this report discusses the way these principles are applied to the restorative treatment of a clinical case. In this case, the potential of IPS e.max Press, or rather the power of the MT ingot, comes to fruition through a smart symbiosis of monolithic pressing and microlayering.