| Oral/Dental
Care - Oral Manifestations of Radiation Therapy to the Head & Neck Radiation therapy is associated with a variety of side effects that vary according to total dosage, rate of radiation delivery, fraction size, field of radiation, radiation source, previous surgical intervention and individual patient status. Patients receive radiation therapy to the oral cavity and/or salivary glands for the treatment of tumors in the oral cavity, oropharynx, nasopharynx, larynx and salivary glands, and for the treatment of lymphomas and leukemias. Patients may undergo radiation therapy for 3-7 weeks with a total dose ranging from 3,000 to >7,000 centigray (cGy), depending on tumor type and location. Hodgkin's and non-Hodgkin's lymphomas require less radiation than other solid tumors of the head and neck.
Taste LossAlteration and loss of taste may begin with the first 200-400 cGy. After three weeks of therapy, it takes 500-8,000 times normal concentrations of taste stimulant to elicit a normal taste response. Taste acuity levels usually return to normal 2-4 months following completion of therapy, if adequate saliva is available.
XerostomiaSalivary gland acini within the field of radiation may be permanently destroyed during therapy. Saliva is reduced in volume and altered in consistency. Reduction is dependent upon the total dose of radiation, degree of salivary gland involvement in the field of radiation, and individual patient variables. Flow may be reduced 50% by the end of the first week, and further reduction in volume (up to 100%) may occur. The saliva produced is more mucinous and acidic, and it may distribute less easily throughout the mouth. Salivary gland tissue does not recover from radiation damage, although some patients may perceive an improvement in salivary output over time.
Mucositis The mucosa becomes edematous, erythematous, pseudomembranous, and sometimes ulcerated. Pain varies considerably in severity and may be intensified by certain foods. The patient may develop problems in swallowing and speaking. Mucositis usually occurs after the second week of radiation therapy. The lips, buccal mucosa, soft palate, borders of tongue and floor of mouth are at greater risk of mucositis. Severe symptoms usually resolve within six weeks following completion of therapy.
Infection Secondary infections are common. While candidiasis is most common, all bacterial, mycotic and viral organisms may cause infections.
Nutritional Deficiency Eating difficulty caused by xerostomia, mucositis and dysphagia may lead to nutritional compromise and dehydration.
Dental Demineralization/"Radiation Caries" Rapid demineralization and breakdown of tooth structure may occur following radiation therapy. The process may be recognized early after treatment. The teeth need not be in the direct field of radiation therapy. Demineralization results when the parotid and/or submandibular/sublingual glands are included in the field of radiation. A diminished supply of saliva, particularly of resting flow from the submandibular/sublingual glands, deprives the oral cavity of the protective components of saliva and the tooth structure of the calcium and phosphate ions necessary to maintain the hydroxyapatite content of enamel and dentin. Although some patients do not clinically appear to be xerostomic after radiation therapy, they may experience a change in the quality of their saliva, leading to rapid dental demineralization. Even a 25% decrease in saliva may result in dental breakdown.
Trismus Spasms and/or fibrosis of the muscles of mastication and temporomandibular joint may develop when the muscles and/or TMJ are in the field of radiation. This may impair saliva circulation and interfere with oral hygiene procedures and dietary intake.
Soft tissue necrosis/Osteoradionecrosis (ORN) Soft tissue and bone necrosis may develop because tissues within the field of radiation become hypovascular, hypoxic and hypocellular. This process may be spontaneous or result from trauma, leading to non-healing soft tissue and bone lesions, and necrosis. Trauma may result from tooth extraction, invasive periodontal procedures and intraoral prosthetic appliances. The mandible is much more susceptible to ORN than the maxilla. The non-healing bone may become secondarily infected.
Developmental Maxillofacial Deformity Children who receive radiation therapy to facial bones and developing dental structures may experience altered craniofacial growth and tooth development. The degree of deformity depends on the dose of radiation therapy and the age of the child at the time of therapy.
Long-Term Effects of Radiation Therapy Although patients receiving radiation therapy will experience dramatic resolution of the acute effects following the completion of treatment, the long-term effects are progressive and significant. Fibrosis of tissues and hyalinization of blood vessels contribute to decreased perfusion of tissues that intensifies with time. Radiation Therapy - Evaluation and Treatment Plan Pre-radiation therapy dental appointments should establish a dentition that the patient will be able to maintain for the rest of his or her life. The evaluation should consider the patient’s previous interest in oral health, as well as current motivation to comply with a rigorous and lifelong preventive oral health program. The financial commitment of the preventive measures and the costly reality and complications of non-compliance should be strongly emphasized.
All hopeless and questionable teeth (i.e. teeth with furcation involvement or advanced periodontitis, or teeth that are impacted, nonessential or nonrestorable), implants with questionable prognosis, root fragments and other bone pathology within the field of radiation should be removed prior to radiation. Since osteoradionecrosis has been reported to develop in irradiated jaws as late as 25 years following radiation therapy, serious consideration must be given to the extraction of any teeth that may be a problem in the future. Total odontectomy, followed by alveoloplasty or alveolectomy should be performed on patients with minimal potential for maintaining adequate oral hygiene, a significant percentage of non-restorable teeth and/or severe periodontitis.
Oral Surgery Extractions and surgery, with tension-free primary tissue closure and antibiotic coverage, should be performed to allow at least 14 days of healing prior to initiation of radiation therapy. The precise time interval depends upon the extent of surgical insult and the philosophy of the treatment center.
Pre-prosthetic surgery, including removal of interfering tori and exostoses, should be performed at this time since additional surgical procedures are contraindicated on irradiated bone.
Prosthodontic Evaluation Proper evaluation of existing removable prostheses is essential. The patient should leave appliances out of the mouth as much as possible during the period of therapy, especially if mucositis develops. New prostheses should not be constructed for at least 3-6 months following radiation, depending upon the integrity of the mucosa, severity of xerostomia and surgical scarring.
Temporomandibular Disorders Patients with temporomandibular disorders can experience increased complications during and after radiation therapy to the head and neck. Conservative management should be planned at the time of the pretherapy evaluation.
Additional Needs of Children Evaluate the dentition and estimate the exfoliation of primary teeth. Remove mobile teeth. Remove gingival operculum if there is a risk for entrapment of food debris or infection.
Tobacco Cessation Patients who use tobacco should be advised to quit. Response to radiation therapy is improved in individuals that do not smoke. Facilitation in the quitting process may involve referral for cessation counseling or to a support group and, when appropriate, nicotine replacement therapy.
Dietary Counseling Analyze and modify the patient’s daily dietary habits to eliminate highly cariogenic foods and drinks without compromising adequate caloric intake. Aggressive use of over-the-counter medications high in sugar content should be discouraged.
Treatment and Maintenance of the Teeth Provide periodontal care, including prophylaxis and home care instruction. Perform high priority restorations and eliminate sites of irritation. Remove orthodontic bands if they are within the field of radiation.
To prevent demineralization of tooth structure, “radiation caries,” the minerals normally provided by saliva must be replaced on a daily basis for the rest of the patient’s life. The presence of fluoride ions enhances the teeth’s ability to uptake calcium and phosphate ions; therefore, fluoride gel, and on occasion a calcium phosphate remineralizing gel, should be applied to the teeth in custom gel-applicator trays.
Several days before the initiation of radiation therapy, patients should begin their daily five-minute application of a fluoride gel. Acceptable fluoride gels include a 1.1% neutral pH sodium fluoride or a 0.4% stannous fluoride (unflavored). A neutral pH fluoride should be used by patients with porcelain crowns. Fluoride rinses do not provide adequate fluoride coverage of teeth to prevent demineralization.
Custom Gel-Applicator Trays Custom gel-applicator trays are fabricated on a vacu-form machine using a flexible vinyl mouthguard material. The trays should completely cover all tooth structure. The edges should be tapered to reduce bulkiness and should be smoothed with either a rag wheel or felt cone or it can be flamed. To prevent the risk of soft and/or hard tissue necrosis, the trays must not irritate the gingival or mucosal tissues.
The adaptation of the trays to cervical margins of the teeth should be checked and modified from time to time, as this thermoplastic material will gradually lose intimacy of fit.
Patient Instruction for Gel Application The patient should be instructed to perform the following:
Patients During Radiation Therapy Dental Treatment Restorative treatment not accomplished prior to radiation therapy may be performed during the first two weeks of radiation or until the patient begins to experience mucositis.
Infection Control Ulcerations and dry, friable tissues may easily become infected. Culture suspected infections and prescribe treatment in cooperation with the radiation oncologist. Fungal infections should be treated with a topical antifungal agent, preferably one without sugar.
Dietary Counseling Guidance in food selection should be offered in order to maintain the patient's nutritional status and to control caries.
Trismus When the muscles of mastication are in the direct field of radiation, instruct the patient to exercise the muscles three times daily by opening and closing the mouth 20 times as far as possible without causing pain. Opening against gentle pressure generated by placing the hand against the midline mandible may also be helpful. This exercise may lessen the degree of trismus experienced by the patient.
Patient Home Care Excellent oral hygiene must be maintained. The teeth should be brushed with an extra-soft nylon bristle toothbrush after each meal and at bedtime. Dental floss should be used daily. If the oral tissues become painful, the mouth may be rinsed with a topical anesthetic before brushing. Softening the toothbrush in hot water before use may be helpful. Plaque may be wiped from the oral tissues with gauze moistened in a baking soda-saline solution. Water irrigating devices should be used only on the lowest setting. Sharp objects should not be put in the mouth.
The mouth must be kept as moist and clean as possible to reduce development of infection and pain. Over-the-counter alcohol-based mouthwashes and full-strength peroxide should not be used due to their drying and irritating effects. Long-term use of diluted peroxide solutions may disrupt the normal oral flora.
The mouth should be rinsed with a baking soda-saline solution frequently throughout the day, followed by a plain water rinse. The solution may be prepared by mixing 1-2 tsp(s) of baking soda and 1/2 tsp of salt with one quart of water. Salt may be eliminated according to patient preference. This solution may be put in a disposable irrigation bag and hung overhead to allow the solution to flow through the mouth. The solution must not be swallowed.
Daily fluoride gel applications in custom gel-applicator trays should continue unless pain from mucositis becomes significant. As soon as the mucositis resolves, the patient should resume daily gel application.
Patients should not wear removable prostheses if any irritation, mucositis or ulceration develops. Some radiation oncologists request that the patient not wear dentures throughout the entire therapy period. Dentures should be cleansed daily and soaked in an antimicrobial denture-soaking solution. When out of the mouth, they should be stored in clean water that is changed daily. Denture adhesives should not be used.
Suggestions for symptomatic relief of xerostomia and mucositis pain should be offered to the patient Patients Following Radiation Therapy Dental Recall/Restorative Treatment Following completion of all radiation therapy and resolution of the acute oral side effects, the patient should be placed on a dental recall schedule at intervals appropriate to the maintenance of excellent oral status. A typical recall frequency for prophylaxis and home care evaluation may be every four to eight weeks for the first six months following radiation therapy. The frequency of recall visits should be adjusted according to the needs of the individual patient.
Perform restorative dental procedures as needed. Consideration should be given to the use of glass ionomer and resin-bonded restoration of remineralized tooth structure. The prophylactic bonding of sealant resins to remineralized tooth structure may be beneficial. (See next section on remineralizing gels). For the pediatric patient, consideration should be given to restoration with stainless steel crowns.
Control of Demineralization/Patient Home Care Patients may believe that, over time, saliva levels have recovered. However, it is well documented that the quantity and/or quality of saliva is typically permanently compromised and never recovers to normal values. Therefore fluoride gel applications must be continued at a frequency sufficient to maintain tooth mineralization. This may require lifelong daily application(s) of either a 1.1% neutral sodium fluoride or a 0.4% stannous fluoride. A neutral pH fluoride should be used by patients with porcelain crowns.
For patients with early or persistent enamel breakdown, remineralization of teeth may be achieved by regular application of a calcium phosphate remineralizing gel in gel-applicator trays. Applications are made after tooth cleansing procedures have been completed. In the severely xerostomic patient, these procedures should be completed after every meal and before retiring to bed, in addition to a daily fluoride application. Frequency can rarely be reduced because xerostomia is usually lifelong. Patients with enamel breakdown, but who demonstrate compliance with oral hygiene procedures and gel applications, may need a dietary analysis to assist with the elimination of cariogenic foods or oral medications. Chlorhexidine products may help control cariogenic bacterial plaque.
Continue assistance with the palliative management of xerostomia and the identification and treatment of oral infections.
Monitor patient for evidence of trismus. Encourage daily jaw exercises.
Prosthodontics Prosthodontic appliances may be constructed after the mucositis has resolved and integrity of the oral tissues has been reestablished. Appliances must be carefully adjusted to prevent tissue irritation and the initiation of soft or hard tissue necrosis. Some patients may never re-acquire the ability to tolerate a tissue-borne prostheses because of friable tissues and xerostomia.
For the comprehensive management of major dental breakdown, or of significant prosthetic need, referral to a maxillofacial prosthodontist with experience in the treatment of cancer patients is indicated when possible.
Oral Surgery Invasive surgical procedures involving exposure of irradiated bone should be avoided if at all possible, due to risk for osteoradionecrosis. If tooth extraction is unavoidable, extreme caution must be exercised. Conservative surgical technique, antibiotic coverage for at least two weeks post-operatively, and the use of hyperbaric oxygen therapy for tissue preparation may all be essential to assure complete healing. Alternatives to tooth extraction include coronal amputation and root canal therapy Additional Oral Management
Measures Palliative Measures for Xerostomia and Pain There is no one product that has demonstrated complete effectiveness in the relief of xerostomia and pain. A clean, well-hydrated mouth may prevent exacerbation of the complications associated with cancer therapies and may be the most important suggestion for easing these complaints. The following empirical suggestions may be helpful, and an empathetic ear may greatly enhance the patient's comfort.
Measures to Assist the Xerostomic Patient Dietary Counseling To aid in swallowing, foods may be softened or thinned with liquids such as skim milk, broth or water. In addition, melted margarine or gravy may be added to foods if fat consumption is not a problem. Foods with some bulk may be easier to swallow than liquids. Dry foods may be dunked in liquids. Alcohol and drinks with caffeine may cause additional dryness. Carbonated beverages with sugar and diet drinks with phosphoric and citric acids should be discouraged.
Saliva Stimulation The use of a sugarless gum or candy containing xylitol as a sweetening agent or a wax bolus may help stimulate salivary flow. It may also be helpful to keep a cherry pit or small glass bead in the mouth. Sialogogues such as pilocarpine (and anetholetrithione, which is available in Canada and Europe) may benefit some patients with residual salivary gland function.
Saliva Substitutes A trial of a commercial oral lubricant may be suggested for the patient with a dry mouth. Water alone remains a frequently used mouth-wetting agent, although a small amount of glycerine (1/4 tsp) may be added to eight ounces of water to offer longer-lasting relief from dryness.
Palliative Measures for Xerostomia and Pain Measures for the Palliation of Pain It is imperative to determine the etiology of pain prior to suggesting palliative measures.
Topical preparation A variety of topical anesthetic and coating agents are available to palliate painful mucositis.
Analgesics Systemic analgesics, such as acetaminophen or ibuprofen, may be taken according to product directions. More potent analgesics may be needed. Dietary counseling Patients should be aware that irritating foods such as acidic citrus fruits and juices, hot and spicy products and rough-textured foods may cause additional discomfort. Straws may be used to drink liquids. Temporary comfort may be achieved by sucking on ice chips or popsicles. The patient's diet may consist of foods that are easy to chew and swallow such as milk shakes, cooked cereals and scrambled eggs; soft and pureed fruits and vegetables such as apple sauce and mashed potatoes; custards, puddings and gelatins; and high-moisture foods such as sorbets and ices.
Infection control Early identification and treatment of infections will diminish the severity of mucositis and help control pain. The following products and practices may increase dryness and pain and should be avoided: Commercial mouthwashes Most over-the-counter mouthwashes should not be used because they have a high alcohol content and can dry and irritate the oral tissues. Flavoring and coloring agents also may be irritating. Alcohol-free mouth-washes are available.
Peroxide Excessive use of hydrogen peroxide 3% and carbamide peroxide 10% are acidic and may be irritating to the oral tissues and disrupt the normal oral flora. When used, hydrogen peroxide 3% should be diluted (one part peroxide to four parts of water or saline) and should be limited to short-term use.
Alcohol and Tobacco Products Use should be discouraged due to the irritating and carcinogenic effects. Passive smoke may be filtered from rooms with an electronic filtering appliance.
The BC Cancer Agency
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