Mr Fernandez y Lombardi, do you believe in micro-layering as a technique that is capable of streamlining procedures in the dental laboratory while fulfilling high aesthetic demands?
Yes, I truly believe that micro-layering is the next step in the evolution of indirect restorative techniques and materials. This evolution is driven by improvements in the area of framework materials, which are becoming more and more tooth-like in their appearance. We have moved from metal to opaque, high-strength zirconia and—more recently—to high-translucency multilayered zirconia and lithium disilicate, which no longer require thick porcelain layers to achieve lifelike outcomes. In this context, it’s only natural that a new technique has emerged.

Are there any other benefits arising from the low firing temperature?
The low firing temperature definitely offers an economic benefit in that the process consumes less energy and takes less time compared with high-temperature firing cycles. Moreover, the wear on the furnace is reduced. Finally, the low temperature is of interest for users of CERABIEN ZR in specific indications: some ceramists like to combine systems, especially in cases with artificial gingiva. They can create the porcelain work on the teeth with CERABIEN ZR first and then individualise the gingival area with CERABIEN MiLai. Owing to the low firing temperature, the form, colour and surface of the previously applied veneering porcelain will remain stable.

Do you have any application technique recommendations for CERABIEN MiLai?
The best aesthetic outcomes are obtained by using the internal stain technique. By applying the stains first, it is possible to create natural depth effects despite the minimal thickness of the porcelain layer. The stains are easy to use, and the outcomes are impressive. The micro-layer of porcelain applied on top acts like a window imitating the enamel, which contributes to a tooth-like appearance. Owing to the compact line-up and easily manageable effects, this technique is even suitable for beginners.

Does the procedure differ depending on the base material (lithium disilicate vs zirconia)?
Most of the steps are identical. However, surface conditioning may be different depending on the material used (as described in the material manufacturer’s instructions for use). Moreover, Value Liner 1 or Value Liner 2 is typically used on lithium disilicate for wash baking, whereas Translucent or Luster are recommended for this step on zirconia. When space is limited, internal stains may be applied directly. All the following steps—the optional but highly recommended application of internal stains, the build-up of Translucent or Luster and baking, morphological corrections, the glaze bake and finishing—are identical.

What are the options for glazing?
CERABIEN MiLai porcelains offer a self-glazing effect obtained by fine polishing (with PEARL SURFACE C) followed by glaze baking. This leads to a natural gloss and maintains the anatomical details. Alternatively, CERABIEN ZR FC Paste Stain Glaze or Clear Glaze can be applied and fixed by baking. These liquid ceramics allow users to add some structural details and make the surface appear glossier. However, the procedure is more time-consuming owing to the additional application step.

Do you have any recommendations regarding the indication-specific selection of the framework or base material?
Traditionally, lithium disilicate has been the material of choice for aesthetic single anterior restorations, whereas zirconia was predominantly used for multi-unit restorations and restorations in the posterior area. Owing to the availability of KATANA Zirconia STML, KATANA Zirconia UTML and CERABIEN MiLai, zirconia is becoming increasingly attractive for the production of minimally invasive veneers, crowns and the like. A thin-walled restoration made of KATANA Zirconia, speed-sintered in just a few minutes and combined with a thin layer of CERABIEN MiLai results in an incredibly strong restoration with several aspects that lithium disilicate simply cannot match. The preparation technique for zirconia is much more favourable for dentists—for example, marginal adaptation and biocompatibility, especially regarding gingival healing, are superior.

Aesthetically, there is no risk of a greyish effect when using zirconia with CERABIEN MiLai, but lithium disilicate needs to be treated with Value Liner to prevent this. Additionally, the ease of cementation with PANAVIA SA Cement Universal further enhances the quality of the restoration in the fastest possible time frame, allowing for quick and flexible responses to dentists’ needs.

You mentioned speed sintering as a factor contributing to a streamlined workflow. Studies have shown, however, that this step might weaken the mechanical and aesthetic properties of zirconia. Do you recommend speed sintering despite this?
Indeed, speed sintering does affect the translucency and flexural strength of some zirconia variants. This is probably the reason why dental technicians have been reluctant to change their established practices of sintering overnight—despite the availability of high-speed furnaces. However, KATANA Zirconia is an exception. Owing to our unique powder formulation, we are able to offer zirconia with a composition that is completely different from other brands of dental zirconia. With this, we are able to fundamentally change the traditional workflow of the end user and offer greater flexibility, speed and efficiency, resulting in reduced energy consumption, stress and cost.

In a study conducted at the University of Alabama at Birmingham in the US, three different high-translucency zirconia materials, including KATANA Zirconia Block (KATANA Zirconia STML), were sintered according to a traditional and a high-speed sintering schedule. Prior to sintering and afterwards, the three-point bending strength, translucency and grain structure were analysed. The material from Kuraray Noritake Dental was the only zirconia with properties that remained unaffected after speed sintering. Internal testing confirmed this finding for all variants of the KATANA Zirconia multi-layered series. As a result, we do recommend speed sintering of our materials, delivering true economic and time advantages.

In light of the highly potent materials for micro-layering that are now available, do you think that full ceramic layering is going to be a thing of the past?
I am convinced that in the near future the great majority of dental restorations will be produced using aesthetic framework materials and simplified micro-layering techniques. However, full porcelain layering is here to stay. There will always be a demand for a few highly skilled ceramists serving the needs of individuals with the highest aesthetic demands. It is like tailor-made versus off-the-peg suits: the tailor-made ones are the best you can buy, but most people wear off-the-peg ones, which are perfectly adequate in virtually every environment.