Incisal Translucency Skill or Ignorance?

Modern dentistry is deeply focused on replicating nature to provide the best aesthetic outcome for our patients. The more we are invested in tooth morphology the better eye we develop to notice the fine details of a tooth. This includes producing life-like textures imitating the primary, secondary, and tertiary morphology of a tooth.

 

However, are we standing too close to the elephant? Are we exaggerating our interpretation of what teeth look like? Or are we lost in the translation of the macro details of a tooth, which made us lose the sense of what a natural tooth really looks like? An example of what I’m referring to is the incisal translucency of anterior teeth. Technicians and dentists are showing off their talent to produce the “see-through” layer and brand it as “natural”.

 

Before we jump in, I’d like to start by defining what translucency really means. In the glossary of prosthodontic terms, translucency is defined as “having the appearance between complete opacity and complete transparency; partially opaque” keyword PARTIALLY OPAQUE. Now I ask you, is that what we see now?

What I keep seeing, is a tooth with a black smudge in the incisal end. This glassy see-through layer is not like what the enamel looks like on the incisal edge and the result is far from natural.

 

The three layers of a tooth are the pulp, the dentine and the enamel. To fabricate a veneer or composite restoration, there are different layers used. These layers differ in their value and chroma effects which dictate how the result will be. The dentine shade is usually opaquer, and richer in chroma (colour). The enamel shade is more translucent and usually dictates the value of the shade (light or dark). So, when technicians start layering the ceramic powders, they usually mix the different layers in the same sequence as their location in the teeth. So mamelons are layered in dentine ceramic and the final layer is layered with enamel (fig 1). That being said, the enamel powder can come in high translucency, which will make it resemble the glass in the windows and become see-through.

 

 

 

 

 

 

 

 

 

 

                                                                                                                       fig 1. The different ceramic layers

 

Here is where the problem starts. To show off their skills and produce the translucent ends, the technician will increase the glassy see-through enamel layer to have the translucent ends. Viola! now you have translucency, THAT’S ALL THERE IS TO IT. If you are dealing with opaque material eg. zirconia, translucent illusions can be achieved by using stains.

 

The dentist then brands this ugly black stain look as “natural” as if it was something difficult to achieve (it’s not) (fig 2). I think to myself, where did it go wrong? Are we standing too close to the elephant so now we cannot differentiate between natural and macro-morphology? Or are we simply ignorant when it comes to material properties?

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                                                                                                                      fig 2 Exaggerated ugly incisal translucency

 

The skilful technician will have the subtle touch of adding just the right amount of translucent enamel layer to mimic the natural enamel of a tooth. That is the real skill. Certainly, a gap is formed, and the word natural has lost its credibility. Maybe we need to start looking at natural teeth more, and restorations less.