CANCER-DENTAL AND ORAL COMPLICATIONS cont...

Xerostomia....

Xerostomia (dry mouth) changes the ability of the mouth to neutralize acid, clean the teeth and gums, and protect the mouth from infection. Saliva is needed for taste, swallowing, and speech. Xerostomia is the thickening of, or reduction in volume of saliva. Symptoms include dryness, a sore or burning feeling (especially on the tongue), cracked lips, cuts or cracks at the corners of the mouth, changes in the surface of the tongue , and difficulty wearing dentures. An extremely dry mouth will also impair proper speaking, and the swallowing of foods. Saliva contains important protective enzymes which aid in the prevention of tooth decay and periodontal disease. To protect against tooth decay during and after treatments, patients with xerostomia should apply fluoride to the teeth daily to protect them. Besides a reduction in salivary volume, treatments can cause saliva to become thick, stringy and annoying to the patient. Once saliva is thickened or reduced in volume, minerals can be lost from the teeth (demineralization), and needed minerals (calcium, phosphorus) are not redeposited on the teeth. Plaque becomes heavy and thick, and the acids produced after eating sugary foods can cause additional mineral loss. All this contributes to dental decay. It is essential that once salivary function begins to diminish that attention to oral hygiene must be increased. It is not uncommon for post treatment individuals to visit their dental hygienist at rates far more frequently than what is recommended for the general public. Quarterly for cleanings would not be too often, and some patients go even more frequently because even with the most diligent program at home they are unable to prevent the accumulation of plaque and calculus on the teeth. Xerostomia is typically not reversible, and the chronic effects may persist for months or years, with recovery depending on the area radiated, the total dose, and the individual patient. Obviously when the salivary glands are directly in the field of radiation, the condition is unavoidable. New developments in the manner in which radiation is delivered such a IMRT treatments. More about IMRT and radio-protective drugs such as Amifostine may reduce the effects of radiaion induced xerostomia.

Synthetic saliva solutions and saliva substitute lubricants are helpful in many patients with dry mouth, and some favorable reports have been published. Oral Balance, an over-the-counter gel, also available as a liquid which can be carried easily in the pocket, is a good example. In some patients in whom the salivary complaint is related to the "thickness" (excess mucous-type secretions), guaifenesin as a liquid or tablet may help as a mucolytic agent. There are a variety of over the counter products that contain this active ingredient - read labels. During the treatment phase of these moisture changes in the mouth the thickening of saliva and mucous production can be problematic. OTC products such as MUCinex which contain the same active ingredient, may be helpful in this area.

More about saliva.

Management of xerostomia in oral cancer patients during and after treatments Mary Brosky, DMD, University of Minnesota.

Demineralization....

Demineralization of the teeth and the breakdown of tooth structure can also occur as a result of treatment. This is not necessarily the result of the teeth being in the direct field of radiation therapy. Demineralization may also result when the parotid and/or submandibular/sublingual salivary glands are included in the field of radiation, and are damaged. A diminished supply of saliva, or a change in the quality of saliva, particularly of the resting flow from the submanibular/sublingual galnds, deprives the oral cavity of the protective componenets of saliva, and the calcium and phosphate ions necessary to maintain the hydroxyapatite content of tooth enamel and dentin. Demineralization may contribute to dental caries, or hypersensitive teeth.

Scrupulous hygiene must be maintained indefinitely; daily topical fluoride applications are effective as a means of combating the tendency of oral cancer patients to develp dental caries which can be a by-product of demineralization.

LOSS OF TASTE....

With radiation therapy, a loss of taste (dysgeusia) may also occur due to damage of the taste bud cells. These cells occur primarily in the tongue papilla and are very sensitive to radiation. These cells usually are capable of repopulating within four months following treatment, but some permanent impairment may remain. There are essentially four tastes; sweet, sour, bitter, and salty. Patients are unique, and different tastes will return at different rates after treatment, and in different amounts. The degree to which taste returns is highly variable and varies from patient to patient. Xerostomia and mucositis also contribue to dysgeusia.


to be cont....

CANCER - DENTAL AND ORAL COMPLICATIONS cont. from February 2, 2011

SURGICAL ISSUES...

Patients who undergo a surgical solution to the removal of their cancer may have unique problems related to the oral structure which are now missing. While necessary in some cases, surgery can be deforming. Reconstructive surgery may be employed during the primary surgery or afterwards as a secondary procedure.

Alterations to the structures of the oral cavity and face result in complications which frequently require prosthetic reconstructure after completion of the healing process.

The use of dental and facial implants may be employed in achieving the final solution. The success rates of these osteointegrated implants, is well substantiated. Implants to replace teeth and to hold maxillofacial prosthesis, have been placed successfully even in irradiated tissues, though with lower success rates.

Mucositis, which can be caused by radiation or chemotherapy, results from the mitotic death of the basal cells of the mucosal epithelium. Portions of the gastrointestinal tract become inflamed, and red, burn-like or ulcer-like sores appear throughout the mouth.

Patients being treated with chemotherapy for tumors anywhere in their bodies, or by radiotherapy, are often plagued with mucositis. Severity depends on the quality of dental hygiene, the treatment schedule, the irradicated area and the amount of radiation given, as well as the age of the patient. Late effects can be characterized by thinning of the mucosa (the soft tissue of the oral cavity), and submucosal ulceration and necrosis. Oral mucositis is made worse by infection. The mouth can become infected, and the loss of soft tissues in the mouth can allow disease-causing organisms to enter the bloodstream. Once the mouth is affected by treatments, even the normal, good bacteria that exists as part of the natural flora of our mouth, can cause infections, as well as disease-causing organisms picked up from other sources. As the white blood cell count decreases as a result of treatments, the frequency and seriousness of infection increases. Patients who have low white blood cell counts over a long period of time, are at more risk of developing serious infections. Antibiotics used over a long period of time can change the number of normal, beneficial bacterial organisms in the mouth. Their decreased numbers may allow an excessive growth of fungi. Steroids given at the same time as treatments can also make the problem worse. Most oral infections in patients with solid tumors are caused by yeast and other fungi, while the rest are caused by viruses (such as herpes) and bacteria.

One of the more common fungal infections is Candidiasis, which colonizes the damaged mucosa.

Mucosaal healing should be complete within three to six weeks after radiation therapy, and mucositis should begin to resolve at the same time.

Radioprotectors may also be employed to reduce the negative biological effects of radiation therapy, and they may prove useful in reducing tissue toxicity. A dentist or oncologist may prescribe viscous topical anesthetics such a lidocaine to reduce discomfort, or a "Miracle Mix" (a tissue coating agent and numbing agent) to aid in oral comfort, if the symptoms are especially bad. While an uncomfortable aspect of treatment, mucositis will heal by itself shortly after treatement is completed.

to be continued....

DENTAL SEALANTS: PROTECTING AGAINST TOOTH DECAY:

The use of dental sealants is universally recognized as a cost-effective and proven evidence-based method of reducing the incidence of dental caries in high-risk populations. Sealant utilization in California remains low, however, especially among groups such as low-income children who have the highest risk of developing tooth decay.

The October 2010 issue of the Journal of the California Dental Association (CDA) is devoted to evidence-based recommendations intended to increase the dental professional's comfort level in making appropriate contemporary sealant recommendation and placement decisions. Based on the ADA's 2008 sealant guidlines, the Journal includes information on the science related to sealant materials available, tooth preparation, and the use of adhesives prior to sealant placement. The similarities and differences between sealant use in private practice and in public healthcare settings, including school-based programs, is also examined as well as prevention and mangement protocols based on caries risk assessment. "Dental sealants can reduce the incidence of tooth decay in school children by more than 70%," said Paul Reggiardo, DDS, chair of the CDA Policy Developement Council's 2008 Sealant Workgroup. "The Journal's recommentations give oral healthcare providers effective guidelines on the utilization and placement of sealants."

In addition to the Journal, the CDA has also published a new dental sealant resource fact sheet and patient education flyer. The fact sheeet is printed in multiple languages and contains information on the benefits of dental sealants, which are proven to be the most effective method of reducing cavities in children.

CANCER....DENTAL AND ORAL COMPLICATIONS

The likelihood is high that aggressive cancer treatment will have toxic effects on normal cells as well as cancer cells. The gastrointestinal tract, including the mouth, is particularly prone to damage. This is true whether the treatment is radiation or chemotherapy. Most patients being treated for head and neck cancer will experience some oral complications, and while most of these are manageable, complications can sometimes become severe enough that treatment must be completely stopped. In addition, surgical solutions to tumor removal may lead to oral and nutritional problems as well.

The most common oral problems occurring after radiation and chemotherapy are mucositis (an inflammation of the mucous membranes in the mouth), infection, pain and bleeding. Other possible complications might include dehydration and malnutrition, commonly brought on by difficulties in swallowing (dysphagia). Radiation therapy to the head and neck may injure the glands that produce saliva (xerostomia), or damage the muscles and joints of the jaw and neck (trismus). These treatments may also cause hypovascularization (reduction in blood vessels and blood supply) of the bones of the maxilla or mandible (the bones of the mouth). In addition, treatments may affect other forms of dental disease (caries, or soft tissue complications), or even cause bone death (osteonecrosis).

By identifying patients at risk for oral complications, health care providers are able to start preventive measure before cancer therapy begins, reducing the occurrence of problems brought about by different treatment modalities. The most important risk factors leading to problems are oral or dental disease that already exists, and poor oral care during cancer therapy. Other risk factors include the type of cancer, the chemotherapy type and schedule used, the area irradiated and how much radiation is given, how low blood counts are decreased and for how long, the patient's age, and the general condition of the patient's health pre-treatment.

Pre-existing oral conditions may increase the risk of infection or other problems. Problems such as calculus and tartar on the teeth, broken teeth, the condition and quality of existing dental repairs such as crowns or fillings, periodontal disease, and appliances such as bridges, partial dentures or other removable fixtures can make therapy more difficult later on. Bacteria and fungi can live in the mouth, and may develop into an infection when the immune system is not working well, or when white blood cell counts are low. Both of these factors can be caused by the treatment methods used. Where the gums (gingiva) or other soft tissues are irritated, tissues can thin and waste away, causing sores in the mouth. These complications can result in a significant reduction in the quality of life for the patient.

One way in which radiation therapy kills cancer cells, is by shrinking blood vessels in the affected area. Fast growing tumor cells require more oxygen and nutrients than normal cells, and they are"oxygen starved" to death. Additionally, both radiation therapy to the head and neck and chemotherapy drugs affect the ability of cells to divide, an efficient manner in which to kill cancer cells. This however, also makes it difficult for tissues in the mouth to repair themselves in the treated sites. Therefore, people being treated with radiation therapy for head and neck tumors, frequently have side effects associated with the radiation itself, or with the decreased blood flow. The mucus membranes, or soft tissues inside our mouth and throat, are tender to this lifesaving treatment; salivary glands are especially sensitive as well. The damage to these tissues and glands depends on the amount and kind of radiation used, the total dose, and the size of the area irradiated. Damage caused by radiation therapy affects the tissues for the rest of the patient's life. These hard and soft tissues are more easily damaged after treatment has been completed, and normal methods of cell repair do not work as well once cells have been exposed to radiation. It is of extreme importance that the patient's dentist is aware and educated in the issues regarding radiation therapy. The special dental considerations surrounding post-treatment care last forever.

CHEMOTHERAPY ISSUES...

Chemotherapy kills cancer cells by taxing some aspects of their life cycles more than it taxes the life cycle of most normal cells. however normal cells in the body can be susceptible to the stress of chemotherapy. When the white blood cell count is lowest, oral tissues are most prone to damage. The mouth is able to recover only when the white blood cell count returns to normal. The lips, tongue, floor of the mouth, inside by the cheeks, and soft palate (the upper back of the mouth) are more affected by chemotherapy drugs than are the hard palate (the upper front of the mouth) and the gingiva surrounding the teeth. Some chemotherapy drugs are more likely to cause problems in the mouth, especially when they are given in high doses, in repeating schedules, or when given simultaneously with radiation therapy. Spicy foods, abrasive foods, and alcohol should be avoided so as not to agggravate the sore tissues, and water should be consumed in high volume to maintain the mostness of tissues and the body's fluid balance. During and shortly after chemotherapy, an oncologist should be consulted before any dental care is performed. With white blood counts and clotting factors at low levels, dental treatment should be postponed until after a blood test confirms a return to normal levels. Chemotherapy can also lead to neurotoxicity, a persistent, deep pain that mimics a toothache, but that has no dental or mucosal source.

to be continued......