When a tooth is so weakened by decay that there is insufficient tooth structure to retain a filling, the restoration of choice is a crown.
What remains of the tooth is reduced to a stump under local anaesthetic and an accurate mould or impression is made. This is sent to a dental laboratory for construction of the crown. In the meantime, the tooth is protected with a temporary crown, usually made of plastic.
Crowns can be made of ceramic, gold or a combination of the two, depending on a number of factors relating to the position in the mouth, the chewing load and the desired appearance. They are all custom made for each individual tooth.
A second visit is needed to remove the temporary crown and fit the permanent one.
The loss of only one or two teeth can be problematic, particularly at the front of the mouth. Replacement is usually by one of two options although in cases of more extensive loss we occasionally still use dentures.
If the tooth loss is due to untreatable decay and the adjacent teeth have also been extensively filled, the most straightforward replacement is by bridgework.
This entails preparing the teeth either side of the space for crowns and spanning across the gap with a bridge made to look like the missing teeth. It is cemented in place and looks and functions just like natural teeth.
Preparation of a tooth for a crown or bridge involves a considerable amount of ‘dentistry’ and is never undertaken lightly in our practice. It is often the best restoration in the circumstances but comes with a considerable biological and financial cost. There must always be a good reason for taking a drill to a tooth!
If a tooth is lost through trauma or an accident, often its neighbours are completely health and it would be inappropriate to cut these down for a conventional bridge. In these situations it is occasionally possible to construct a Maryland bridge. This is essentially a single tooth on a ‘wing’ that is simply bonded to the neighbour with little or no tooth preparation. This obviously fits well with our policy of minimal intervention but the applications are limited.
Often the most appropriate means of replacement of a missing tooth today is by an implant as there is no involvement of the adjacent teeth.
An implant is effectively an artificial titanium tooth, embedded into the bone with a ceramic crown made to fit the space. Implantology is highly specialised dentistry and until now we have always referred cases to a specialist practice.
However we are starting the training process to be able to offer implants in our practice. Quite literally – watch this space!