Radiotherapy is often an important part of managing oral cancer, but unfortunately it can cause unwanted side effects. The radiotherapy treatment can mean the exposure of the salivary glands, jaws and oral mucosa. The side effects can include xerostomia or dry mouth, losing the sense of taste, or it can lead to the oral tissues becoming inflamed and painful.
In addition patients who have undergone radiation treatment are more at risk of developing radiation caries. This condition occurs as a result of someone receiving radiotherapy to the head and neck area. It is can develop several weeks after the completion of radiation therapy and can affect the teeth in several different ways.
It’s not uncommon to see lesions develop in the teeth at the junction where the teeth meet the gums, called the cervical area. This type of radiation caries can lead to the loss of the crown portion of the tooth. Another common side effect is to see the teeth becoming eroded and worn on the chewing and biting surfaces. This occurs due to the hard outer enamel layer of the tooth becoming softer, meaning the teeth are much more susceptible towards developing cavities, or radiation caries. Another problem that is sometimes seen is that the crown area becomes discolored, and may appear brown or black in color.
Some patients may exhibit one form of radiation caries, while others may develop one or more different forms of this condition. It can affect teeth that weren’t directly irradiated. At the moment the exact effects radiation therapy can have on teeth aren’t yet known, as studies have given conflicting results. Some studies have found demineralization to be a factor in irradiated teeth while others have found no significant difference between non-irradiated tooth enamel and irradiated tooth enamel. Yet more studies have looked at the effects of radiation on the pulp area or central part of the tooth, but again they have proved inconclusive. One factor that does seem to be important is the way radiation therapy affects saliva.
Saliva and Radiation Caries
The therapy has quite an effect on the salivary glands, causing the saliva to become thicker. This can lead to difficulties in eating and speaking, and increases the risk of radiation caries. Saliva has a very important role to play in oral health as it helps keep the mouth clean and reduces the chances of disease by helping to wash away bacteria. In addition saliva is vital in helping teeth to remineralize.
Remineralization is an important process that helps keep the enamel layer of the tooth strong and healthy. Every time you eat something sweet or full of carbohydrates than your teeth come under acid attack. The acid has the effect of leaching out important minerals from the enamel, resulting in it becoming softer. Around half an hour to an hour after eating the mouth becomes less acidic, and important minerals in the saliva are redeposited into the tooth enamel during remineralization. Patients who have undergone radiation therapy can see the composition of the saliva change, as the therapy can affect its antibacterial qualities, and can reduce its capacity for remineralization. With this capacity decreased the likelihood of caries developing due to radiation increases.
Reducing the Risk of Radiation Caries
In an ideal world the salivary glands would be spared during radiation therapy, but obviously this is not always possible. However preventative dental care can help if it is provided before, during and after therapy, although it’s not always possible to prevent radiation caries from developing. It can help to make sure plaque levels are properly controlled, to use fluoride in a form prescribed by your dentist, and use artificial saliva substitutes, or to try to stimulate the flow of saliva.
Choosing your diet carefully can also help reduce the risk, although this can sometimes be quite difficult to do. Patients who have undergone radiation therapy may find it a lot more comfortable to eat soft, sticky foods that are easy to chew and swallow, but unfortunately these aren’t always the best thing for teeth. Choosing a dentist who is experienced in treating cancer patients can help a lot as they understand the clinical and biological implications of cancer therapies, and more able to provide optimal dental treatments.