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Chemotherapy, Radiotherapy and Dental Health

Patients receiving treatment due to cancer go through several changes in their dental health. Among the changes occurring on the oral mucosa, the most common is mucositis. It manifests after the beginning of the treatment, due to the decline or complete loss of epithelium. Mucosa becomes hyperemic (rubescent). Velum, pharynx, palate and cheek mucosa are the first affected regions. Patients have pain and burning complaints. Depending on the inflammatory changes in the mucosa, secondary infections may develop. Candida albicans is the most common oppurtunist infection that can develop. Sense of taste may change and this condition may occur on the first weeks of the treatment, especially on patients with head-neck cancers. It has been reported that parotis, submaxillar, sublingual and other minor salivary glands of patients receiving treatment for head-neck cancers are affected. Consequently, saliva flow and content is adversely affected, causing cotton mouth condition. The burning sensation that derives from cotton mouth, diminished masticatory ability, food getting stuck on teeth and mucosa, hot-cold sensitivity and fungal infections are all conditions which can be observed. Cotton mouth is also the most important cause for decays due to radiation. Saliva's antiseptic properties are disabled with radiotherapy, making saliva unable to perform its protective duties of removing bacteria. As a result, bacterial flora in the mouth undergoes changes and continues on for 4 years. One of the direct causes of raditation on teeth is reduction of minerals on tooth enamel (decalcification). Radiation also leads to insufficient development on teeth in development stage.

The most important complication is the changes forming on bone tissue. Exposed to radiation, the bone becomes brittle and there's a delay in the regeneration of the traumatized bone tissue. Changes are observed on the veins providing blood for the bone cell matrix. Sensitivity to infection increases and the rate of regeneration diminishes or stops altogether, inevitably causing osteoradionecrosis. Osteoradionecrosis is described as the development of bone necrosis and the presence of open bone with or without pain on the area of radiotherapy. Because of the fact that bone tissue is 1.8 times denser than soft tissue, a large portion of the radiation is absorbed by bone tissue. Lower jawbone absorbs more radiation due to its structure compared to upper jawbone. The risk of osteoradionecrosis is consequently bigger. Serious complications may occur when patients are exposed to radiation on head-neck area, aggressive periodontal treatment, infections or mechanic irritation. For this reason, the basic principle for radiotherapy patients is to receive their dental treatments at least 14 days before they are exposed to radiation. On some patients, trismus may occur due to muscle fibrosis following radiotherapy. Trismus is more frequently encountered on patients who require radiation on their temporomandibular joint and chewing muscles (masseter) or following the tumor treatments on nasopharyngeal, palatal and nasal sinuses.

Similar oral changes and complications are observed on chemotherapy patients. Stomatitis in addition to mucositis are observed on such patients. Stomatitis occurs due to trauma on the mucosa with orthodontic apparatus or with infections. The difference between mucositis and stomatitis is that stomatitis is treatable and based on a specific reason while mucositis derives from the impact of chemotherapy on cells.

Candida Albicans is the most common oppurtunist infection. Although, HSV (Herpes Simplex Virus), gram-negative or positive coccus infections develop in addition. Fungal infections such as Candida Albicans are encountered mostly on tongue, cheek mucosa and pharynx.

Symptoms caused as a result of the infection are burning and prickly sensation, pain and ulcer formation on vesicle lesions due to tearing of vesicles. Oral bleeding may occur due to the thrombocytopenia and clotting disorder caused by chemotherapy. Various medications used in chemotherapy cause changes in the saliva quality and quantity on the second day of the treatment. Degree of cotton mouth is directly proportional with duration of treatment. Some medications can cause neurotoxicity. The amount of nerve damage is dependant on the dosage and duration of the treatment. Especially on cases with head-neck area cancer treatment, partial paresthesia may occur on the mouth and its surrounding area after being stimulated by trigeminal nerve. In addition, patients may have intense pain complaints described as toothache on the lower jaw area of molar teeth. It is difficult to diagnose neurotoxicity. Pain complaints subsiding after the cessation of chemotherapy medication confirms the diagnosis.

Precautions

• Patients should schedule their appointments with a dental professional at least a month before radiotherapy and chemotherapy. There has to be a window of at least two weeks between the tooth extraction with radiotherapy and chemotherapy.
• Calculus scaling needs to be performed before radiotherapy. Advanced periodontal treatments have to be performed if necessary. A perfect oral hygiene must be achieved and the patient needs to maintain discreet oral care. Chronic periodontal conditions may move to an acute stage. Oral hygiene is very important due to this condition.
• Fluoride application should be performed to prevent decay formation and the patient needs to use toothpaste with fluoride.

Things to Do During Radiotherapy and Chemotherapy

• Patient needs to maintain a pristine oral hygiene. A soft, small toothbrush should be used and the patient must be careful not to brush harshly. It is not recommended to use oxyjet or electric toothbrushes. If the patients are unable to brush their teeth due to nausea, burning sensation on the gingiva or any other reason, gargling with carbonated water will suffice.
• A proper oral hygiene is necessary in case of acute mucositis. It is highly beneficial to gargle every 3-4 hours with half teaspoonful of salt or soda in warm water. If there is pain during mastication, Dyclone (0.5%) solution should be used 20-30 minutes before every meal.
• Gargling with salty, warm mineral water or topical anesthetics is effective for symptomatic treatment in cases with candida albicans lesions in addition to mucosal changes. Acute or chronic oral fungi are effectively treated by taking "Nystatin". Performing the same treatment on partial removable dentures is essential in controlling the fungal infection.
• Inflammation or ulcerations can be treated with antimicrobial gargle (chlorhexidine gluconate, benzydamine HCl).
• Analgesic and surface covering sticky gel (anestol or protofix) should be used for treating ulceration and inflammations.
• In the case of xerostomia (cotton mouth), frequent hydration is needed with soda water, gum, candy and ice cubes. It is also highly recommended not to consume acidic or spicy food along with too hot or too cold food. Alcohol and tobacco product consumption needs to be discontinued. In addition, potassium iodide medication, lemon tablets, sialogogue agents (Biotene etc.) and artificial saliva should be used.
•  In case of Trismus, regular home exercises are highly recommended. Special apparatus should be made by the dental professional if necessary.