(Editor's Note: This is the third installment in a three-part series about dental care for cancer patients.)
Once a patient is irradiated, the blood supply to the treated area is compromised forever. It will not return. We all need blood to heal from any type of injury. Consequently, since the blood supply to the irradiated area is lessened, the ability to heal — both soft tissues and bone — is compromised. When a tooth is removed, the blood clot that forms in the socket is, in turn “organized” by new tissue as the wound heals. Almost everyone knows of someone who has suffered a “dry socket.” This is a slang term for a tooth extraction site where the blood clot spontaneously aborts, leaving exposed bone. This exposed bone necroses (dies) and is painful. Fortunately in most cases, this is a self-limiting condition, which resolves with minimal treatment. However, the irradiated patient may be left with the exposed bone without the promise of resolution, since there is less blood supply for healing.
Unfortunately, I have had experience with this type of situation. A patient had a tooth removed from an irradiated mandible by an uninformed dentist. When I saw this patient, the bone had eroded down to a small artery, which was bleeding quite profusely. Fortunately, once the bleeding was controlled, the area healed; however, a very tense and potentially devastating episode occurred which could have been prevented.
This prevention starts with proper evaluation by a dentist trained and knowledgeable in management of head and neck cancer patients PRIOR to commencement of radiation therapy. Any tooth removal and/or surgical procedures should be performed and healed before radiation starts. Proactive prevention and education is the best way to prevent osteorandionecrosis or death of bone following irradiation.
The risk of osteoradionecrosis (ORN) can be minimized or eliminated by a little foresight on the part of the clinician treating the patient. Unfortunately, there are occasions when ORN occurs spontaneously following irradiation.
In those instances, careful, insightful and knowledgeable management is crucial to control and limit the potentially devastating ramifications. No one ever wants to remove a tooth from irradiated bone or perform surgery on irradiated bone, lest ORN occur and become unmanageable. If ORN, despite all best efforts, does occur, the patient should immediately see a dentist or oral and maxillofacial surgeon trained and experienced in the care and management of the head and neck cancer patient.
Patients With Dentures
Should every cancer patient be seen by a knowledgeable dentist? Even those patients with dentures? Well fitting, well made dentures use saliva as a seal to keep them in place. Saliva also acts as a lubricant to prevent irritation to the mucosa. Sometimes the relatively benign dry mouth from medications, such as antihistamines, can also cause denture problems. The permanent and profound dry mouth caused by radiation can even render a patient completely incapable of using dentures at all. A well-intentioned dentist may think to provide a “soft liner” for this patient. Unfortunately, the soft liner does not wet as well as hard plastic. It drags on the tissue and acts more like an abrasive on sensitive mucosa. While this irritation might be annoying to the unsuspecting denture patient, the more troubling problem lurking beneath the surface is the prospect of ORN, if bone is exposed. Denture-wearing patients also need to be aware that anything which causes a break in the mucous membrane and exposes bone, can lead to ORN. They need to be careful!
For people with normal dentitions, dental evaluation prior to radiation is critical. Any teeth in the field of radiation that are likely to require removal, or any anticipated gum surgery in the radiated area is best completed 2-3 weeks prior to radiation treatment. The radiation oncologist may or may not call this to the attention of the patient: consequently, the patient must be aware. No one wants to perform dental surgery in an irradiated field, if it can be prevented. However, if it becomes apparent that some invasive procedure is required, it is absolutely critical that the patient be in the care of a practitioner experienced in the management of irradiated patients.
Patients treated with chemotherapy also have a special set of situations. Aside from oral lesions that may develop during therapy, the most pressing concerns are related to blood counts...specifically platelets and white blood cell counts. Platelets are necessary for blood clotting: white cells, to counter and prevent infection. The dentist must be aware of both, since there is a time lag after administration of chemotherapy, when these counts can be depressed to extremely low levels. If the platelets are too low, even cleaning someone’s teeth or giving an injection of local anesthetic can be a problem. Likewise, both the quantity and quality of the white cells are important. Sometimes the patient requires antibiotic coverage prior to dental care. In short, the dentist must be aware of these special circumstances, in order to safely and effectively care for the patient.
As always, your dentist should be the first person consulted and care and guidance with these situations.