Complications refers to every type of undesired problem which can occur during root treatment!

We will only discuss specific complications, general side-effects such as nausea or dizziness due to a local anaesthetic are not mentioned here.

The most common type of complication is that not all root canals are filled. Either a canal is overlooked – as seen in this animation the tooth has 4 canals and only three are filled, or else the root is not filled up to the tip, as can be seen in this picture. There are many reasons for an „incomplete filling“ – crooked roots, instruments breaking, lack of motivation on the part of the dentist, a clumsy or inexperienced dentist, and moreover, most dental insurance plans pay when a root is more than half full.

An x-ray can be used to check the quality of dental work, here you can see an x-ray of a badly filled tooth (to the right) and a well-filled tooth to the left. The canals to the left are evenly sealed, conically shaped and filled to the tip (shown by the white line in the x-ray).

The problem with badly filled teeth is that even years later the bone may become infected or a cyst may form – patients feel a dull ache without knowing where it’s coming from. Here you can see a cyst which appeared years after faulty root treatment. The cyst is highlighted in blue – it is easy to see how the cyst has displaced the nerve in the lower jaw (highlighted in red) – and the patient complained of a prickly feeling in her lower lip.

A fractured instrument was what led to this problem. This is another common problem in root treatment – here you can see a white streak in the front root, this is part of an instrument which broke off and blocked the root so that it could not be filled up completely.

Sometimes the filling is too deep, and the material enters the surrounding tissue. It does not always need to be removed, only if the patient feels an ache or the bone gets inflamed – bi-annual x-rays can be used to check for this. The excess material should also be removed if it is too close to the nerve of the lower jaw, or the inside of the mouth – even if it doesn’t hurt. The animation shows how in the process of root treatment, the material is pressed against the nerve canal of the lower jaw.

Overlooking canals is a complication, as already mentioned. Molars usually have 3-4 roots and 3-4 canals. But some teeth may have up to six, which is why it is necessary to use a microscope or magnifying glass. The picture shows a tooth under a microscope with four canals surrounded by a coffer dam.

Dark discolorations of the tooth after root treatment either indicate blood or unclean work. The canal should be clean and free of blood and bacteria, otherwise bacteria dissolve the blood, and the iron contained in haemoglobin turns into iron sulfide, which is black – and the tooth turns dark. Using a coffer dam helps to avoid this complication. Here you can see a tooth protected against saliva and bacteria during root treatment by means of a coffer dam.

For an experienced dentist, root treatment is a very simple and necessary procedure for saving teeth, if it is performed well then the tooth can last for decades.