Large Fillings

What are the potential problems?

• There are a number of considerations to take into account when a large filling is necessary.
• In heavily filled teeth where the filling is close to the nerve there is usually some decay present that must be removed.
• Amalgam fillings don’t seal the cavity completely but rely on the chemical effect of the silver and the mercury in them to act as a bacteriostatic agent to slow the spread of bacteria under the filling.
• This means that where there is some mild infection under the filling, that may be causing some inflammation of the nerve tissue, there is no pressure build up as it can leak away.
• It is not possible in most cases for the dentist to identify this problem at this stage.
• This doesn’t mean there is nothing wrong, just that there are no symptoms. The problem will get progressively worse until a painful abscess develops.
• Bonded composite fillings do seal the tooth completely.
• In about 95% of these situations, once the new filling is in place the tooth settles down quite quickly with just a little sensitivity for the first few days.
• In about 5% of cases the inflammation doesn’t settle because the nerve has already been affected too much, and the initial discomfort gets progressively worse as the pressure increases until it can cause really severe pain. A secondary effect is that the pressure causes the tooth to become subluxed (slightly pushed out of the socket) so that it comes into contact with the opposite tooth before the other teeth. This accelerates the problem and can lead to an abscess quite quickly.

• What to do about it?

• There are 2 options:
o It would be possible to root fill any potentially susceptible tooth at the outset. The disadvantage is that only 5% will actually go on to develop a problem, and root canal treatment has a failure rate of over 5% in molar teeth because of the internal anatomy of some teeth. This can only be determined after the tooth has been extracted, not usually before treatment. Root canal treatment is often more expensive than the filling and will usually lead eventually to the need for a crown and possibly a reinforcing post.
o The filling can be placed in the tooth and in the small number of cases where a problem subsequently develops, then the additional treatment can be carried out to deal with the problem at that time. This reduces the overall cost in most cases, but does rely on the patient returning in good time if symptoms build up if the painful latter stages are to be avoided.

The infection/ inflammation will usually respond in the short term (usually a few days) to antibiotics and anti-inflammatory analgesics, but will recur if active treatment is not taken up fairly quickly.