Q. I’ve asked my dentist to replace my old crowns as they have unsightly dark lines around them which I can see when I smile. When I first had them fitted, they were perfect. I’m worried the same thing will happen again. Will my crowns fade over time?

A. This dark line is usually the metal surface underneath the porcelain showing. This can be caused by a number of factors,including your oral hygiene around the crown,the amount of gum recession etc.

It’s best to discuss the situation beforehand with your dentist. Newer technology now means that sometimes all porcelain crowns can be used which look more lifelike.