Dental Issues & hyperbaric oxygen (HBO) in head & neck cancer patients

Dental issues can be challenging for laryngectomees, mainly because of the long term effects of radiation therapy (RT). (see Side effects of radiation page) Dental care before RT and maintenance of good dental hygiene afterwards can prevent many problems.

Dental care before radiation therapy for head and neck cancer

Proper dental care before radiation therapy for head and neck cancer is crucial to prevent complications and improve treatment outcomes. Here are the key points regarding dental care before radiation:

• A comprehensive oral examination and necessary dental treatments should be completed before starting radiation therapy. This includes treating any existing dental infections, decayed teeth, or periodontal disease.
• Teeth with poor prognosis or those that cannot be restored should be extracted at least 2-3 weeks before radiation to allow proper healing and reduce the risk of osteoradionecrosis.
• Oral hygiene instructions and fluoride trays should be provided to maintain good oral health during and after radiation.
• Removable dental prostheses like dentures should be adjusted or remade to ensure proper fit after radiation-induced changes in oral tissues.

 

Importance of Pre-Radiation Dental Care:

• Eliminates existing sources of oral infection and potential complications during radiation therapy.
• Reduces the risk of osteoradionecrosis, which can occur after dental extractions in irradiated bone.
• Allows time for proper healing of any oral surgical sites before radiation starts.
• Establishes optimal oral health baseline to minimize radiation-induced side effects like mucositis, xerostomia (dry mouth), and radiation caries.
• Improves patient's quality of life and ability to maintain adequate nutrition during cancer treatment.

In summary, comprehensive pre-radiation dental evaluation and treatment are essential for head and neck cancer patients to prevent and manage oral complications during and after radiation therapy.

Dental Issues after radiation treatment

RT for head and neck cancers can lead to several long-term dental side effects:

• Dry Mouth (Xerostomia): Radiation can damage the salivary glands, leading to a permanent decrease in saliva production. Dry mouth increases the risk of dental caries, oral infections like candidiasis, difficulty swallowing, and compromised taste.
• Increased Risk of Dental Caries: Lack of saliva leads to a higher risk of tooth decay and cavities due to the loss of saliva's protective effects.
• Periodontal Disease: Radiation can cause soft tissue changes that increase the risk of periodontal (gum) disease and tooth loss.
• Osteoradionecrosis of the Jaw (see below): This condition causes poor healing and bone death in the jaw after trauma like tooth extractions. It occurs more frequently after high radiation doses.
• Trismus (see page x): Radiation-induced fibrosis of the muscles used for opening the mouth can limit mouth opening over time.

Other potential long-term effects include oral candidiasis, taste changes, and soft tissue necrosis. Proper dental evaluation and preventive care before, during, and after radiation is crucial to minimize these complications.

Long term effects on the oral cavity include:

• Reduced blood supply to the maxillary and mandibular bones.
• Reduced production and changes in the chemical composition of saliva.
• Changes in the bacteria that colonize the mouth.

Because of these effects dental caries, soreness, and gingival and periodontal inflammation can be particularly problematic. These can be lessened by maintaining good oral and dental hygiene such as cleaning, flossing, and using fluoridated toothpaste after each meal when possible. Using a special fluoridated preparation to gargle or apply on the gum helps in preventing dental carries. Keeping well hydrated and using saliva substitute when needed are also important.

 

It is advisable that patients receiving radiation therapy to the head and neck visit their dentist for a thorough oral examination several weeks prior to initiation of the treatment and be examined at a regular semiannual or annual basis throughout life. Getting regular dental cleaning by a dental hygienist or a dentist are also important.

In the past, some dentists and radiation oncologists recommended the removal of most or all teeth before receiving irradiation therapy. The current recommendation is the removal of only non restorable teeth, those with advanced periodontal disease, mobile teeth with furcation involvement, residual roots, necrotic teeth, or mandibular teeth that receive high levels of radiation. Individuals who have adequate oral hygiene, can be expected to receive regular dental care, and wish to keep their teeth should not undergo removal of healthy teeth that are not in the radiation field.

Because radiation treatment alters the blood supply to the maxillary and mandibular bones patients may be at risk of developing bone necrosis (osteoradionecrosis) at those sites. Tooth extraction, dental implants and dental disease in irradiated areas can lead to the development of osteoradionecrosis. Patients should inform their dentist about their past radiation treatment prior to these procedures. The risk of acquiring osteoradionecrosis may be reduced by the administration of a series of hyperbaric oxygen therapy (see below) before and after extraction or dental surgery. This is recommended if the involved teeth, or planned implants are at an area that had been exposed to a high dose of radiation. Consulting the radiation oncologist who delivered the radiation treatment can be helpful in determining if this is necessary. 

Dental prophylaxis can reduce the risk of developing dental problems leading to bone necrosis. Special fluoride treatments may help to prevent dental problems, along with brushing, flossing, and having one's teeth cleaned regularly.

A home care dental lifelong routine is recommended:

•  Flossing each tooth and brushing with toothpaste after each meal.
•  Brushing the tongue with a tongue brush or a soft bristled toothbrush once a day.
• Use dental water jet to clean the teeth at least once a day.
• Use fluoride tooth paste.
• Rinsing with a baking soda rinse daily. Baking soda helps neutralize the mouth. The rinse is made of one teaspoon of baking soda added to 12 oz. of water. The baking soda rinse can be used throughout the day.
• Using fluoride in a fluoride tary once a day. These preparations are commercially available and can also be custom made by dentists. They are applied over the teeth for 10 minutes. One should not rinse, drink, or eat for 30 minutes after fluoride application.

   

Fluoride trays

Fluoride application on a custom made tray

Stomach acid reflux is also very common after head and neck surgery, especially in individuals who have had partial or complete laryngectomy. (see page on eating, swallowing and smelling) This can also cause dental erosion (especially of the lower jaw) and, ultimately teeth loss. 

Measures to reduce and prevent acid reflux include:

• Losing weight (in those who are overweight)
• Reducing stress and practicing relaxation techniques
• Avoiding foods that worsen symptoms (e.g., coffee, chocolate, alcohol, peppermint, and fatty foods
• Stopping smoking and passive exposure to smoke
• Eating small amounts of food several times a day rather than large meals
• Siting when eating and staying upright 30-60 minutes later
• Avoiding lying down for 2-3 hours after a meal
• Elevating the beds' head side by 6-8 inches (by putting blocks of wood under 2 legs of the bed or a wedge under the mattress) or by using pillows to elevate the upper portion of the body by at least about 45 degrees
• Taking a medication that reduces the production of stomach acids, as prescribed by one's physician
• When bending down, bending the knees rather than bending the upper body 

Hyperbaric oxygen therapy

Hyperbaric oxygen (HBO) therapy involves breathing pure oxygen in a pressurized room. HBO is a well-established treatment for decompression sickness (a hazard of scuba diving) and can be used to prevent osteoradionecrosis. 

HBO is used to treat a wide range of medical conditions including: bubbles of air in the blood vessels (arterial gas embolism), decompression sickness, carbon monoxide poisoning, a wound that won't heal, a crush injury, gangrene, skin or bone infection causing tissue death (such as osteoradionecrosis), radiation injuries, burns, skin grafts or skin flaps at risk of tissue death, and severe anemia.

HBO therapy alone can often effectively treat decompression sickness, arterial gas embolism and severe carbon monoxide poisoning. To effectively treat other conditions, HBO therapy is used as part of a comprehensive treatment plan and is administered in conjunction with additional therapies and medications that fit  individual needs.

To be effective, HBO therapy requires more than one session. The number of sessions required depends on the medical condition. Some conditions, such as carbon monoxide poisoning, can be treated in as few as three visits. Others, such as osteoradionecrosis, and non-healing wounds, may require 20 to 30 treatments. Those who require dental extraction are often 20 treatments prior to the procedure and 10 following it.

HBO can be used in patients with head and neck cancer for the treatment of osteoradionecrosis, refractory osteomyelitis, dental procedures (i.e., extractions), avert the risk of flap or graft failure, and necrotizing soft tissue and wound infections. Antibiotics are administered in conjunction with HBO to those with infections.

Patients should inform their dentists about their radiation therapy prior to extraction or dental surgery. Osteonecrosis may be prevented by administration of a series of  HBO therapy before and after these procedures. This is recommended if the involved tooth is in an area that has been exposed to a high dose of radiation. Consulting the radiation oncologist who delivered the radiation treatment can be helpful in determining the extent of prior exposure. 

In an HBO therapy chamber, the air pressure is raised up to three times higher than normal air pressure. Under these conditions, the lungs can gather much more oxygen than would be possible when breathing pure oxygen at normal air pressure.

The blood carries this oxygen throughout the body, stimulating the release of chemicals called "growth factors" and stem cells that promote healing. When tissue is injured, it requires even more oxygen to survive. HBO therapy increases the amount of oxygen in the blood and can temporarily restore normal levels of blood gases and tissue function. These promote healing and the ability of the tissues to fight infection.

A patient is wheeled into a hyperbaric chamber

HBO therapy can be performed as outpatient procedure and does not require hospitalization. Hospitalized patients may need to be transported to and from the HBO therapy site if it is an outside facility.

Treatment can be performed in one of two settings:

·        A unit designed for one person in an individual (monoplace) unit where the patient lies down on a padded table that slides into a clear plastic tube.

           A HBO chamber designed for one person

·        A chamber designed to accommodate several people in a multiperson HBO room where the patient may sit or lie down. A hood or mask delivers the oxygen.

             

              A HBO chamber designed to accommodate several people

During HBO therapy the increased air pressure creates a temporary feeling of fullness in the ears - similar to the one felt in an airplane or at a high altitude that can be relieved by yawning. 

A therapy session may last from one to two hours. Members of the health care team monitor the patient throughout the session. Following HBO therapy the patient may feel lightheaded. Typically, this feeling dissipates within a few minutes. 

There is no evidence indicating that HBO neither acts as a stimulator of tumor growth nor as an enhancer of recurrence. On the other hand, there is evidence that implies that HBO might have tumor-inhibitory effects in certain cancer subtypes.

HBO therapy is generally safe, and complications are rare. Most complications are caused by the increased air pressure and volume barotrauma in the middle ear (i.e., tympanic membrane rupture), sinuses, and lungs. Other complication include increased heart output, seizure activity as a result of oxygen toxicity, and effects on the eye (i.e., temporary nearsightedness or myopia, enhancing a cataract). These can include:  (myopia), middle ear and inner ear injuries (including leaking fluid and eardrum rupture due to increased air pressure), organ damage caused by air pressure changes (barotrauma), and seizures 

HBO is absolutely contraindicated in those with untreated pneumothorax. It is relatively contraindicated in those with claustrophobia (who can be pretreated with anti-anxiety medications), advanced congestive heart failure or obstructive lung disease, bullous lung disease, while receiving chemotherapy, seizure disorder, active smoking, pregnancy, chronic sinus congestion, and fever.

Pure oxygen can cause a fire if there is a source of ignition, such as a spark or flame, and adequate fuel. It is therefore forbidden to take items that could ignite a fire (e.g., lighters or battery powered devices) into the HBO therapy room.

The risk of fire inside the chamber can be averted by with these safety measures: 

• Patients should wear cotton cloth and gown
• Avoiding the use of battery operated devices inside the chamber. Medical devices (i.e., pacemaker, defibrillator) are allowed after they have been tested
• Avoiding cosmetics
• No newspaper, tobacco products or matches are allowed
• Grounding the patient with a wire