Furcation means division.
In dentistry we understand it to mean the division of the roots, primarily in teeth with more than one root.
In the upper jaw we speak of trifurcation (since the rear teeth of the upper jaw have three roots). In the lower jaw we speak of bifurcation (since the lower jaw rear teeth have two roots).
Here you see a tooth. You can recognise the crown. This then goes on into the root stem. In the picture you can clearly recognise the transitional zone. We call this the enamel-cement border. Unlike the tooth crown, the tooth roots don’t have a surface of enamel but rather of a material which is similar to bone, namely root cement.
The root stem divides into its particular roots and each area of division is described as furcation. In this case we have a three root tooth and we thus speak of trifurcation.
The root stem is usually surrounded by bone. Should a retreat of the bone due to bacterial inflammation as a result of periodontitis occur the stem of the root and even the furcation may come to lie away from the bone. In this hard to clean area bacteria invade immediately and a rapid loss of bone will be the result. In the furcation scar tissue will develop, known as granulation tissue.
We differentiate between various grades of severity of furcation problems. Here you see a tooth and bone that has retreated due to periodontitis. In the furcation inflammed transformed tissues remain and very many bacteria.
If the probe penetrates the furcation by up to 3mm, we talk about Grade I furcation problems. Up to 6mm we talk about Grade II furcation problems. If the probe goes right through the furcation then this means we have a Grade III furcation problem.
What is important is to halt the inflammation caused by bacteria as otherwise bone will continue to be lost until ultimately the entire tooth will be lost. In order to halt the inflammation the existing gaps must be freed from bacteria, i.e. made cleanable. Since with a normal toothbrush, as shown in the animation, only flat, easily accessible surfaces can be cleaned the bristles will never be able to reach the furcation.
Grade I and II furcation problems can be given very good treatment in which, for example the lost bone/periodontium is reconstructed. Unfortunately regeneration is no longer possible with Grade III problems. The aim is therefore to arrest the inflammation by cleaning. To do this the Grade III problem must become cleanable, by means of interdontal brushes for example.
In order to be able to clean right through without pain, the dentist may enlarge the furcation slightly. This procedure is referred to as tunnelling.
Here you see an x-ray of a rear tooth, one can clearly recognise the loss of bone in the furcation region. The dentist tunnels the tooth first – the black spot is more clearly visible now. If the anatomy of the root canal is not well-suited for tunnelling, then the dentist may carry out a root amputation, which is also a was to treat a furcation problem. In the example shown the inflammation was not brought under control by tunnelling and therefore a root amputation was carried out.
One can see that, there where previously the roots were located, bone has built up. The x-ray shows the situation one year after a successful root amputation. Sometimes premolarisation is preferred to root amputation. In this case the dentist creates two teeth out of one.
According to the furcation problem and the anatomy of the root canal the dentist will decide which technique to employ. The aim is always the same – the bacteria which the periodontitis has caused must be removed from the gaps – this occurs when the problem area becomes cleanable for you.
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