Earlier posts have discussed the difference in light and color properties between natural tooth structure (enamel & dentin) and their corresponding composite replacements. The difference in translucency, opacity and how the thickness of each layer impacts these properties and others like chroma and value become a challenge chairside when we try and replicate nature. One of the ways to understand and maximize the properties of the composite you are using is a simple bench top exercise. First create a silicone lingual matrix from a model of a patients upper anterior teeth. Next using the current composite that you would employ for a class four or anterior veneer you simply need to create a few teeth and play with the layers and their relative thicknesses.
A2 Gingival Layer
I always layer from the lingual to the labial, starting with a .5mm layer of enamel composite. Next add in the dentin layers. If you are trying to create a natural chroma gradient for a tooth that will ultimately be A1, place an increment of A3 sloping from the gingival to the incisal. Next a layer of A2 that begins more incisally then the last and slopes to the incisal and lastly a layer of A1 that ends in dentinal lobes based on the age of the tooth you are creating.
A1 Dentin Layer
This is also a great way to play with adding incisal effects like opal composites, or characterization for craze lines or decalcification spots between the dentin layer you have created and the final enamel layer. Finish with a layer of enamel and the interproximal enamel. With a single matrix you can make a number of composite incisors varying the way you layer the composite to create a gradient or monchromatic result, with no or lots of effects and characterization.
Composite Incisor
This time at the bench will take what you can accomplish for your patients to the next level and give you a working knowledge of the composite you are using.
in this exersize if your silicone matrix of some anterior teeth that have class 4 type of lesions (or fractures etc.that you have created for this drill) when the layering is done on the silicone matrix do you then place filled matrix back on model (after altering model to create the problems you will ultimately find on some patients) since curing through the matrix would not work well. I guess this would be similar to doing a matrx for a veneer or similar situation , are there any transparent silicone materials or must we make a suckdown clear matrix and do your technique
Michael,
there are clear silicone matrix materials that can be cured through. I place the lingual enamel layer on the silicone and then seat the matrix on the tooth and then cure from the facial.
Lee Ann, is that to say, in your response to Michael, that you sandwich the uncured composite between the silicone matrix and the tooth, thereby expressing some excess from around the tooth to the front, and then you cure that from the front? I’m sorry I’m having a tough time visualizing what you are saying here. Or are you referring to the lingual layer of composite is applied first to the matrix, shaped, then cured from the facial, as you are going through this exercise, getting ready to add the next, more facial, internal dentin layer to the lingual enamel, again curing from the facial, stepping it out at each layer to the facial?
Another question for you on the subject of composites: is it ok to utilize different brands of composites in the different layers as I have found some brands have some qualities I like better in different layers? -or is it better to stick to the same brand of materials when layering and characterizing?
Thank you for your blog. I don’t often get to look at it, but I am a fan since I took a class you gave here in Seattle a couple of years ago.
I place the lingual enamel shade composite int he matrix outside the mouth. i then seat the matrix against the tooth and finally cure this layer int he mouth with the matrix in place.
As for mixing and matching brands, many many people do this and have great success, so if you have a particular brand of opaque composite or for the enamel layer you want to use a microfill you don;t have to worry about mixing and matching based on what I know about composites.