Restoring Class V Abfraction Lesions

Retention of class V restorations can be a real problem until you understand a little physics.

First of all, do you understand what an abfraction lesion is? An abfraction is a notch in a tooth near the gumline. It usually occurs in the cementum, and is very smooth. We told our patients for years that these were caused by over-aggressive brushing. But then in the 90's someone published a study where they had discovered these lesions subgingivally, which seriously undermined the toothbrush abrasion hypothesis. Further study showed that these were stress-related lesions. They are caused by flexing of the teeth, and while they usually occur on the facial aspects of teeth, they can also occur on the lingual.

This brings us to the issue of retention. Restorations of these lesions are the bane of adhesive technology. It will be the first restoration to de-bond, and the ultimate test of any bonding agent has been its effectiveness in one of these class V situations. However, the flex stress theory of the cause of the abfraction lesion leads naturally to the flex stress theory of retention of abfraction restorations. It has been discovered that when the restorative material is flexible, retention increases dramatically.

Hence, when you restore an abfraction lesion, use a microfill. Microfills are less stiff, more flexible. In our practice, after we discovered this connection and began using microfills exclusively in abfraction situations, our failure rate decreased dramatically. Here are some choices that work well for abfraction lesions:

• Silux Plus. An advantage of Silux Plus is that it is manufactured in several shades that are quite dark and thus compatible with the root surface.

• Renamel. Renamel is a tough, esthetic material that takes a high shine and hold up well in class V situations.

• Heliomolar. With Heliomolar you have a radiopaque option, which is helpful in case the insurance company wants you to prove that you actually restored the tooth.

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