PRINTED IN TCI WEEKLY NEWS
February 9th, 2013
Crowns, Bridges & Veneers
When talking with patients about crowns, caps, post-crowns, bridges and veneers I find that there can sometimes be some confusion. In this article I want to explain the differences between them and when that particular course of treatment might be suitable.
Veneers
A veneer is a thin porcelain cover designed to go on the outside surface of a tooth. Veneers are only used on front teeth and are generally used for cosmetic purposes, for example to restore chipped or broken teeth, or to change the colour, size or shape of teeth.
The teeth generally require a small amount of preparation after which the patient will wear temporary veneers while the porcelain ones are being produced by the laboratory. This period is around 2 -3 weeks. The porcelain veneers are then fixed to the teeth with a tooth coloured bonding material to give a completely natural appearance. Veneers are generally strong although still more delicate than a full coverage crown just due to the fact that the porcelain, whilst strong, is thinner. I advise patients with veneers to avoid putting too much pressure on the edges and so to avoid chewing on bones eg. ribs or chicken wings, finger nails and the ends of pens!
Crowns
A more robust solution than a veneer is a crown, sometimes called a cap. A crown covers the whole tooth above the gum and is suitable for both front and back teeth. Crowns involve a greater reduction of the natural tooth’s surface than a veneer but the result is greater strength. Crowns are used both for cosmetic and clinical reasons, for example when a tooth is badly decayed but the root is still intact.
Crowns can be made from a variety of materials designed for difference circumstances; all porcelain (like a veneer but around the whole tooth) or porcelain with a strengthened core such as zirconium, procera or metal. In all these cases only the tooth-coloured porcelain is visible and, when completed, the teeth should look indistinguishable from your natural teeth. Crowns can be made purely of gold. This is a cosmetic choice and with the current price of gold can be a rather expensive option.
A post-crown is where the tooth has been root filled and a fibre-glass post is fixed into the root canal. A structure is built up onto this which holds the crown. A more old-fashioned method is to use a metal post or screw. However, this is found to sometimes cause stress fractures in the root and is less satisfactory than modern techniques.
Bridges
A bridge is used to replace one or more missing teeth, for example after an extraction, and, unlike a denture, is permanently fixed in place. A bridge is attached to adjacent teeth (either natural teeth or implants) and carries one or more artificial crowns to fill the gap of the missing teeth. If several or lots of teeth are missing more than one bridge maybe the solution. I always prefer to break down bridges into smaller units which gives greater strength and stability and if necessary use implants to replace missing teeth to reduce the span of larger bridges. Bridges are made from porcelain covering metal and again when complete should visibly be indistinguishable from your natural teeth.
