Special Care Dentistry- Cancer, Respiratory Disorders and Endocrine Disorders.
04 May 2011
Cancer of the head and neck region/
Head and neck cancer represents a mixed group of malignancies affecting a number of sites in the nasopharyngeal tract. Most are sensitive to a treatment regime of surgery followed by radiotherapy and, increasingly, in combination with chemotherapy. Many patients who present with head and neck cancer do so by virtue of their lifestyle; patients are predominantly from lower socioeconomic groups, are likely to be poor dental attenders, neglect their oral health and smoke and drink to excess. The disease is therefore potentially preventable.
Oral and dental considerations:
- Patients suffering from head and neck cancer often require extensive dental care prior to curative surgery and/or radiotherapy if their oral health is not to be further compromised after cancer treatment. These patients are more prone to extensive and rapid caries. It is important to the successful outcome of rehabilitation care, which may include implant treatment, that patients retain as many of their own teeth as possible because not only does this improve the stability of dentures but it has been shown to significantly improve the quality of life for the cancer patients.
- Dental extractions must be completed before radiotherapy in order to avoid the serious sequelae of osteoradionecrosis, (necrosis of the bone) which is a risk if teeth requiring extraction have not been removed prior to treatment.
- Some patients will require obturators to be made because surgery may remove part of the jaws. Patients who require radiotherapy to the head and neck region will require a stent to shield dental tissues from the therapeutic beam. For post-radiotherapy patients, intra-oral appliances that act as a reservoir for topical fluoride therapy are advisable and the dentist should have these ready for the patient after their surgery.
Mucositis, seen without exception in head and neck irradiation but also with chemotherapy, is the most common and also distressing side-effect of the treatment. It impacts seriously on the quality of a patient's life in terms of pain, inability to eat, swallow and talk. Patients need to be monitored carefully because mucositis, when combined with neutropenia, can lead to septicaemia and can be potentially life threatening. It can be so severe that it cancer treatment may have to be interrupted. Prevention of mucositis, which is also a sequel of high-dose chemotherapy, is important and should be undertaken in conjunction with the inter-professional team managing the care of the patient. Patients with head and neck cancer who undergo radiotherapy will experience profound lack of saliva in most cases. The management of this relies on aggressive caries prevention, regular dental care and saliva stimulants/substitutes where needed by patients.
The five year survival rate of head and neck cancer is 40%, although this is dependent on the stage of the cancer. Palliative care is defined as the active total care of patients whose condition or disease is not responsive to curative treatment. The aim of the care is to relieve symptoms and pain and also the active support of patient and family members, physically and psychologically, in order to ensure the best quality of life for all. There is an important role for dental input into a palliative care team since oral signs and symptoms of disease can be the most distressing.
Acute upper respiratory infections are commonly associated with the common cold and make the delivery of dental treatment more challenging for the patient as well as increasing the exposure of the dentist and dental nurse to infection. When a nasal airway is mandatory in, for example, inhalation sedation or general anaesthetic, elective treatment needs to be postponed.
Asthma is defined as repeated, reversible attacks of wheeze on breathing out, shortness of breath and a cough as a result of narrowing of the airway. Inflammation and infection may follow. Asthma is a syndrome caused by allergy, pollution, infections, stress, exercise and non-compliance with drugs. Management of asthma consists of a) the avoidance of allergens and known precipitating factors and b) the use of inhaled bronchodilators and steroids. To avoid the potential for an acute attack, the patient should be sat up, the patient's airway should then be checked for any obstructions and they should then be advised to use their inhalor if appropriate. If the attack continues despite the above measures being taken then an ambulance should be called immediately.
- The use of epinephrine, aspirin and NSAID's in asthmatic patients should be avoided.
- Local anaesthetic agents such as articaine should be used with caution.
- There is the potential for fungal infections such as Candida in the palate from the use of inhalors.
- Coughing brought on by the condition may lead to gastro-oesophageal reflux which may cause dental erosion.
- Patients taking steroids may have a steroid crisis.
- Respiratory depressants, especially sedatives and tranquillisers should be avoided.
Chronic obstructive airway disease, also known as chronic bronchitis or emphysema, presents as bronchospasm and destruction/distension of the alveoli and is commonly seen in smokers. Patients already taking steroids may need supplemental steroids for invasive, stressful dental care because the endogenous supply of steroid will be suppressed. Patients taking theophylline should not be given erythromycin and some other antimicrobials because they result in toxic levels of theophylline. Sedatives, tranquillisers, hypnotics and narcotics should be avoided. High-flow oxygen may take away the respiratory drive and as such may be a relative contraindication to use of nitrous oxide sedation during which levels of oxygen are higher than in inspired room air. In order to clarify whether this is a real problem, the patient's physician should be consulted.
Scoliosis is a lateral curvature of the spine and patients who suffer this condition may have associated cardiac and respiratory disorders.
Oral and dental considerations:
- General anaesthetics may be contraindicated in a person who has severe scoliosis because of the poor ventilation of portions of the respiratory tree.
- It is very important that seating is comfortable for patients and they are supported well in the chair.
- Chairside aspiration must be high vacuum to protect the airway in a patient in whom respiratory infection would be complex to manage.
Cystic fibrosis is not strictly a respiratory disorder but it mainly affects the respiratory tree, it is the most common inherited conditions. The disorder is of mucus-secreting exocrine glands; therefore effects are seen principally in the respiratory and gastrointestinal tracts. Patients with cystic fibrosis will be taking a number of drugs, some of which may have affected the teeth during development. Orally and dentally, patients may present with:
- Discoloured teeth (from underlying disease or antibiotic therapy)
- Enamel hypoplasia
- Resistance to caries due to high pH of saliva
- Increased prevalence of calculus
- Salivary gland enlargement
Tuberculosis used to be the most common infective disease however better living conditions and widespread availability of antibiotic treatment have reduced its prevalence. Drug resistance and HIV have however brought about a recurrence of this infection. Patients with active TB complain of weight loss, tiredness, night sweats and breathlessness. A chronic cough with blood in the mucus is also a symptom. Transmission of TB is usually by droplets but occasionally from infected, non-pasteurised milk. Patients with active disease or who are still coughing should not receive dental care, except for dental emergencies. After three to four weeks of treatment, patients will usually test negative for active disease.
Integration of the functions of the specialised organs and tissues of the body is undertaken by two mechanisms:
- Electrical impulses carried in the peripheral and central nervous system
- Hormones produced in the endocrine glands
The glands that carry out this function are the:
- Testes and placenta
- Islets of Langerhans in the pancreas
The pituitary gland is situated at the base of the brain and regulates the activity of many of the other endocrine glands by the production of stimulating hormones. It lies closely to a number of important nerves, the cranial nerves in particular. Any alterations in size can put pressure on the cranial nerves and cause visual disturbances. The pituitary gland exerts its influence mainly by stimulating other glands however it does have a primary function in control of growth through the production of growth hormone.
Hyperpituitarism occurs when there is over-production of growth hormones during the growing period and this can cause:
- Early dental development
- Thickening of facial and cranial base bony structures
- Overgrowth of cementum
Hypopituitarism occurs when there is under-production of growth hormones during the growing period and this can cause:
- Delayed dental development
- Alteration in the facial skeleton and cranial base dimensions
- Anterior open bite
The thyroid gland is situated at the base of the neck with a lobe either side of the trachea. Its activity is controlled by thyroid-stimulating hormone (TSH) from the pituitary gland. This is regulated by the amount of thyroid hormone in the blood, which feeds back to the pituitary so preventing over or under-production. The thyroid gland also plays a central part in regulating the metabolic rate.