Chroma, opacity and the tooth
“Layering” can mean more than working in increments: it can mean working with materials with different opacities. Many clinicians focus on chroma and aren’t necessarily thinking about the effect of opacity on overall esthetics – however, it’s just as important to the equation. Teeth are complex esthetically. They themselves are made up of two different layers with different optical properties that affect one another. Dentin, for example, is more opaque than enamel, and is responsible for most of a tooth’s color. However, we see this color through enamel, which distorts that color with its own shade, opacity and thickness – like looking outdoors through frosted glass. With all of this in mind, it only stands to reason that you may need to layer opacities to achieve a natural looking result.
When to use multiple opacities
When approaching the esthetics of any given tooth, anterior or posterior, I look at the tooth I’m going to restore as well as the adjacent teeth. Your restoration should not only match the tooth in question but also fit into the smile as a whole. However, before you can even begin to consider layers, you should first make sure that your materials enable you to match as many cases as possible. For example, 3M™ Filtek™ Supreme Ultra Universal Restorative has more opacities than any other brand: it provides options for dentin, enamel, body and translucent effects. With your materials in hand, here are some possible situations – and solutions – you may encounter:
- A monochromatic tooth with even shade distribution throughout: Keep it simple by using a body shade and single-shade technique.
- A tooth with a gradient of shade: To create a natural gradient effect, you need to place in multiple layers – with a darker dentin layer inside and a more translucent enamel layer outside. Make sure to keep material thickness in mind; if you layer the same thickness of enamel throughout, you will never be able to create that gradient.
The size of the restoration also matters. If it is small, enamel alone may suffice. However, if it’s a large class IV restoration you may need to use both body/dentin and enamel shades. Just like natural dentin, opaque body shades act as a “backing” to the rest of the restoration. Lastly, place a thin layer of enamel on the facial – and a little thicker toward the incisal edge – to achieve the gradient effect.
- A tooth that has many esthetic characteristics and different nuances: These teeth may have a halo in the incisal edge that blocks the light and gives you a wide edge, or may have more translucency in the incisal third. In that case, achieving an esthetic result requires multiple layers – such as dentin, body, enamel, followed by translucent composite. As such, this is a much more complicated layering technique. It’s completely doable, however financial variables may hold some clinicians back. The technique takes longer and requires extensive experience to perform successfully. I believe everyone can do it if they have enough time to practice, but with so many demands on their time, it’s difficult for many dentists to acquire the necessary expertise.