Diseases of the Digestive System - The oral cavity

The Salivary Glands

The smell of food triggers the salivary glands to pour saliva into the mouth; that is what is meant by “mouthwatering” odors. During a meal, saliva is released into the mouth to soften the food as it is chewed.


Stones will sometimes form in the salivary glands or ducts, blocking the ducts and preventing the free flow of saliva into the mouth. After a meal, the swollen saliva-filled glands and ducts slowly empty. The swelling may sometimes be complicated by infection. Surgical removal of the stones is the usual treatment; sometimes the entire gland is removed.


Tumors sometimes invade the salivary gland. An enlarged gland may press on the auditory canal and cause deafness, or it may result in stiffness of the jaw and mild facial palsy. The tumors can grow large enough to be felt by the fingers, and surgery is required to remove them.

Inflammation of the Parotid Glands

Inflammation of the upper ( parotid ) salivary glands may be caused by an infection in the oral cavity, by liver disease, or by malnutrition.


One of the commonest inflammations of the salivary glands, called mumps , occurs especially in children. It is a highly contagious viral disease characterized by inflammation and swelling of one or both parotid salivary glands, and can have serious complications in adults. See “Alphabetic Guide to Child Care” in Ch. 2, The First Dozen Years , for a fuller discussion of mumps.

The Digestive System

Bad Breath (Halitosis)

Poor oral hygiene is the principal cause of offensive mouth odor, or halitosis . It can result from oral tumors, abscesses from decaying teeth, and gum disease or infection. The foul smell is primarily a result of cell decay, and the odors are characteristic of the growth of some microorganisms.

When halitosis results from poor oral sanitation, the treatment is obvious—regular daily tooth brushing and the use of an antiseptic mouthwash. If the halitosis is because of disease of the oral cavity, alimentary tract, or respiratory system, the cure will depend on eradicating the primary cause.

Nonmalignant Lesions

The oral cavity is prone to invasion by several types of microorganisms that cause nonmalignant lesions. The most prominent follow.

Canker Sores

These are of unknown origin and show up as single or multiple small sores near the molar teeth, inside the lips, or in the lining of the mouth. They can be painful but usually heal in a few days.

Fungus Infections

Thrush is the most common oral fungus infection and appears as white round patches inside the cheeks of infants, small children, and sometimes adults. The lesions may involve the entire mouth, tongue, and pharynx. In advanced stages the lesions turn yellow. Malnutrition, especially lack of adequate vitamin B, is the principal cause. Thrush is also one of the opportunistic infections commonly found in persons with AIDS. See also “AIDS” in Ch. 19, Other Diseases of Major Importance . Fungus growth may be aided by the use of antibiotics, which kill normal oral bacteria and permit fungi to flourish.

Tooth Decay and Vitamin Deficiencies

Lack of adequate vitamins in the daily diet is responsible for some types of lesions in the oral cavity. Insufficient vitamin A in children under five may be the cause of malformation in the crown, dentin, and enamel of the teeth. Lack of adequate vitamin C results in bleeding gums. Vitamin D insufficiency may lead to slow tooth development.

An inadequate and improper diet supports tooth decay, which in turn may be complicated by ulcers in the gums and abscesses in the roots of the decaying teeth. A diet with an adequate supply of the deficient vitamins will cause the symptoms to disappear. Infections, abscesses, cysts, or tumors in the mouth require the attention of a physician, dentist, or dental surgeon. See Ch. 22, The Teeth and Gums .


These are primary syphilis lesions, which commonly develop at the lips and tongue. They appear as small, eroding red ulcers that exude yellow matter. They can invade the mouth, tonsils, and pharynx. Penicillin therapy is usually required.

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