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Diseases of the Oral Cavity

Malocclusion of teeth

Malocclusion means the teeth are not aligned properly.

Causes

Occlusion refers to the alignment of teeth and the way that the upper and lower teeth fit together (bite). Ideally, all upper teeth fit slightly over the lower teeth. The points of the molars fit the grooves of the opposite molar.

The upper teeth keep the cheeks and lips from being bitten and the lower teeth protect the tongue.

Malocclusion is most often hereditary, which means the condition is passed down through families. There may be a difference between the size of the upper and lower jaws or between jaw and tooth size, resulting in overcrowding of teeth or in abnormal bite patterns.

Variations in size or structure of either jaw may affect its shape, as can birth defects such as cleft lip and palate. Other causes of malocclusion include:
• Childhood habits such as thumb sucking, tongue thrusting, pacifier use beyond age 3, and prolonged use of a bottle
• Extra teeth, lost teeth, impacted teeth, or abnormally shaped teeth
• Ill-fitting dental fillings, crowns, appliances, retainers, or braces
• Misalignment of jaw fractures after a severe injury
• Tumors of the mouth and jaw

There are different categories of malocclusion:
• Class 1 malocclusion is the most common. The bite is normal, but the upper teeth slightly overlap the lower teeth.
• Class 2 malocclusion, called retrognathism or overbite, occurs when the upper jaw and teeth severely overlap the bottom jaw and teeth.
• Class 3 malocclusion, called prognathism or underbite, occurs when the lower jaw protrudes or juts forward, causing the lower jaw and teeth to overlap the upper jaw and teeth.

Symptoms

• Abnormal alignment of teeth
• Abnormal appearance of the face
• Difficulty or discomfort when biting or chewing
• Speech difficulties (rare) including lisp
• Mouth breathing (breathing through the mouth without closing the lips)

Exams and Tests

Most problems with teeth alignment are discovered by a dentist during a routine exam. The dentist may pull your cheek outward and ask you to bite down to check how well your back teeth come together. If there is any problem, the dentist will usually refer you to an orthodontist for diagnosis and treatment.

Dental x-rays, head or skull x-rays, or facial x-rays may be required. Plaster or plastic molds of the teeth are often needed.


Oral Cancer

About Oral Cancer

Oral cancer includes cancers of the mouth and the pharynx (the back of the throat).

Oral cancer accounts for roughly two percent of all cancers diagnosed annually in the United States. Approximately 35,000 people will be diagnosed with oral cancer each year and about 7,600 will die from the disease.

On average, 60 percent of those with the disease will survive more than 5 years.

Oral cancer most often occurs in people over the age of 40 and affects more than twice as many men as women.

What Puts Someone at Risk?

Tobacco and alcohol use.

Most cases of oral cancer are linked to cigarette smoking, heavy alcohol use, or the use of both tobacco and alcohol together. Using tobacco plus alcohol poses a much greater risk than using either substance alone.

HPV. Infection with the sexually transmitted human papillomavirus (specifically the HPV 16 type) has been linked to a subset of oral cancers.

Age. Risk increases with age. Oral cancer most often occurs in people over the age of 40.

Sun Exposure. Cancer of the lip can be caused by sun exposure.

Diet. A diet low in fruits and vegetables may play a role in oral cancer development.

Possible Signs & Symptoms

See a dentist or physician if any of the following symptoms lasts for more than 2 weeks.:
• A sore, irritation, lump or thick patch in your mouth, lip, or throat
• A white or red patch in your mouth
• A feeling that something is caught in your throat
• Difficulty chewing or swallowing
• Difficulty moving your jaw or tongue
• Numbness in your tongue or other areas of your mouth
• Swelling of your jaw that causes dentures to fit poorly or become uncomfortable
• Pain in one ear without hearing loss

Early Detection

It is important to find oral cancer as early as possible when it can be treated more successfully.

An oral cancer examination can detect early signs of cancer. The exam is painless and takes only a few minutes.

Your regular dental check-up is an excellent opportunity to have the exam. During the exam, your dentist or dental hygienist will check your face, neck, lips, and entire mouth.


Types of Periodontal Disease

There are many different varieties of periodontal disease, and many ways in which these variations manifest themselves. All require immediate treatment by a periodontist to halt the progression and save the gum tissue and bone. Here are some of the most common types of periodontal disease along with the treatments typically performed to correct them:
Healthy Gums - healthy gums are firm and don't bleed. They fit snugly around the teeth.
Gingivitis - gums are mildly inflamed, may appear red or swollen and may bleed during brushing.
Periodontitis - gums begin to separate and recede from the teeth. This allows plaque to move toward the roots, supporting fibers and bone.
Advanced Periodontitis - supporting fibers and bone are destroyed. Teeth become loose and may need to be removed.

Gingivitis

Gingivitis is the mildest and most common form of periodontitis. It is caused by the toxins in plaque and leads to periodontal disease. People at increased risk of developing gingivitis include pregnant women, women taking birth control pills, people with uncontrolled diabetes, steroid users and people who control seizures and blood pressure using medication.

Chronic Periodontal Disease

Chronic periodontal disease is the most common form of the disease, and occurs much more frequently in people over 45. Chronic periodontal disease is characterized by inflammation below the gum line and the progressive destruction of the gingival and bone tissue. It may appear that the teeth are gradually growing in length, but in actuality the gums are gradually recessing.

Aggressive Periodontal Disease

Aggressive periodontal disease is characterized by the rapid loss of gum attachment, the rapid loss of bone tissue and familial aggregation. The disease itself is essentially the same as chronic periodontitis but the progression is much faster. Smokers and those with a family history of this disease are at an increased risk of developing aggressive periodontitis.

Periodontal Disease Relating to Systemic Conditions

Periodontal disease can be a symptom of a disease or condition affecting the rest of the body. Depending on the underlying condition, the disease can behave like aggressive periodontal disease, working quickly to destroy tissue. Heart disease, diabetes and respiratory disease are the most common cofactors, though there are many others. Even in cases where little plaque coats the teeth, many medical conditions intensify and accelerate the progression of periodontal disease.

Necrotizing Periodontal Disease

This form of the disease rapidly worsens and is more prevalent among people who suffer from HIV, immunosuppression, malnutrition, chronic stress or choose to smoke. Tissue death (necrosis) frequently affects the periodontal ligament, gingival tissues and alveolar bone.


TMJ Disorders

Temporomandibular joint and muscle disorders, commonly called "TMJ," are a group of conditions that cause pain and dysfunction in the jaw joint and the muscles that control jaw movement. We don’t know for certain how many people have TMJ disorders, but some estimates suggest that over 10 million Americans are affected. The condition appears to be more common in women than men.

For most people, pain in the area of the jaw joint or muscles does not signal a serious problem. Generally, discomfort from these conditions is occasional and temporary, often occurring in cycles. The pain eventually goes away with little or no treatment. Some people, however, develop significant, long-term symptoms.

If you have questions about TMJ disorders, you are not alone. Researchers, too, are looking for answers to what causes these conditions and what are the best treatments. Until we have scientific evidence for safe and effective treatments, it’s important to avoid, when possible, procedures that can cause permanent changes in your bite or jaw. This booklet provides information you should know if you have been told by a dentist or physician that you have a TMJ disorder.


What causes TMJ disorders?

Trauma to the jaw or temporomandibular joint plays a role in some TMJ disorders. But for most jaw joint and muscle problems, scientists don’t know the causes. For many people, symptoms seem to start without obvious reason. Research disputes the popular belief that a bad bite or orthodontic braces can trigger TMJ disorders. Because the condition is more common in women than in men, scientists are exploring a possible link between female hormones and TMJ disorders.

There is no scientific proof that clicking sounds in the jaw joint lead to serious problems. In fact, jaw clicking is common in the general population. Jaw noises alone, without pain or limited jaw movement, do not indicate a TMJ disorder and do not warrant treatment.

The roles of stress and tooth grinding as major causes of TMJ disorders are also unclear. Many people with these disorders do not grind their teeth, and many long-time tooth grinders do not have painful joint symptoms. Scientists note that people with sore, tender chewing muscles are less likely than others to grind their teeth because it causes pain. Researchers also found that stress seen in many persons with jaw joint and muscle disorders is more likely the result of dealing with chronic jaw pain or dysfunction than the cause of the condition.


Tooth Decay

Tooth decay, known formally as dental caries, has been a serious health problem for all nations since time immemorial. For centuries, tooth decay was thought to be the handiwork of an elusive and, in some cultures, evil tooth worm that gnawed holes into the white, highly mineralized enamel and left all those in its wake in pain. But superstition has yielded to science and its explanation that certain oral bacteria discharge mineral-eroding acid onto the enamel, starting the gradual process of decay. Over the last several decades, dental researchers have made tremendous progress in defining and learning to thwart the decay process. This work has involved the three-pronged strategy of discovery, innovation, and prevention - and produced one of the major public health success stories of the 20th century.

Tooth decay is no longer the national epidemic it was a few generations ago. Millions of American children now have little or no decay, and total tooth loss or edentulism is now much less common. Without research progress in the fight against dental caries and periodontal diseases, there would be an additional 18.6 million Americans age 45 and older with none of their natural teeth.

New technologies will further prevent tooth decay. Research is underway to develop powerful imaging tools that can detect the earliest demineralization of tooth enamel. These tools will allow the application of special solutions to remineralize the tooth and reverse early decay.