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Oral mucosa has the same susceptibility to pathological change as does other covering tissue. Common abnormalities of the skin and the gastrointestinal tract may evidence themselves on oral mucosa. Local, focal oral mucosal lesions, generalized mucosal involvement, or intraoral lesions associated with a systemic problem may be caused by bacterial, fungal, or viral organisms. Benign or malignant lesions must always be considered when examining a patient's mouth.


A vesicle is a circumscribed, superficial elevation on the skin or mucous membrane containing fluid (serum, plasma, or blood). If the vesicle opens, it becomes an ulcer (an inflammatory lesion).

1-43. ULCER (Figure 1- 7)

An ulcer is an open sore of a superficial nature extending below the covering epithelial surface. The base of an ulcer is composed of granulation tissue resulting from initial healing. A secondary infection may develop in an ulcer, resulting in delay of the healing and repair process. A common cause of oral ulceration is trauma, which might even be a result of toothbrush injury. Irritation from a rough or broken tooth surface can also result in ulceration. Some ulcers start with vesicle formation.

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Figure 1-7. Ulcer.

NOTE: This painful ulceration on the lateral border of the tongue represents a nonspecific response to tissue injury. The cause of an ulcer must be determined and appropriate treatment initiated. Normal healing will often result without use of medication.


Initial exposure to the herpes simplex virus results in a generalized oral inflammation followed by vesicle formation and subsequent ulceration. Systemic symptoms of generalized illness accompany this initial attack. Most individuals have their primary exposure to this virus as infants; however, this disease may also occur in young adults and elderly patients. This condition is contagious. Healing occurs spontaneously, with the virus remaining in the nerve tissue, lying dormant in a latent form. Future recurrence of the condition may be either intraoral or extraoral.


The herpes simplex virus may be reactivated (recurrent) in an extraoral form on the lips or, inside the mouth, in an intraoral form.

a. Extraoral Herpes (Figure 1-8). Cold sore blisters, or herpes labialis, are often associated with colds, trauma, fatigue, fevers, and prolonged exposure to the sun and the wind. The common site of occurrence is on the lips at the border with the skin of the face (called the vermilion border). The lesions usually consist of clusters of small vesicles, which in the early stage, contain a clear, transparent fluid. After a few hours, the vesicles rupture and form a crust or scab. The disease is self-limiting and usually disappears in 10 to 14 days. The individual is infective until complete healing has occurred.


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Figure 1-8. Extraoral herpes.

NOTE: Cold sore blisters on the upper lip of this patient are caused by the herpes simplex virus. This recurring infection may be activated by prolonged exposure to sunlight and/or wind.

b. Intraoral Herpes (Figure 1-9). Intraoral herpes forms on extremely firm oral tissue surfaces, such as the palate (roof of the mouth) and attached gingiva. Vesicles are not usually identified because they break down almost immediately into ulcers and coalesce to form multiple jagged ulcerations.

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Figure 1-9. Intraoral herpes.

NOTE: The herpes simplex virus may cause ulcers to form inside the mouth. In this example, the ulcers are on the roof of the mouth (the palate).

c. Complications. The lesions may persist and be very serious in patients with a compromised immune system. While the virus may regress, it does not disappear. The lesions caused by the virus do disappear, however. Also, it is important for dental specialists to recognize that this may be a very serious infection when it occurs in immuno-compromised patients (AIDS, renal transplant, cancer chemotherapy, and so forth).


Recurrent aphthous ulcer (RAU) is a chronic inflammatory disease with repeated episodes of ulcerations. Recent investigations seem to indicate that the aphthous lesion is associated with an altered local immune response. This disease is characterized by small, whitish ulcers with red borders. The disease normally occurs as a single lesion or, infrequently, as multiple lesions on the wet mucous membranes of the lip, tongue, cheek, or floor of the mouth. Lesions appear as depressions on the mucous membrane and are covered by a grayish-white or light-yellow membrane. There is no vesicle formation before the ulcer appears, distinguishing this disease from viral diseases of the oral mucosa. Associated with the development of a recurrent aphthous ulcer is generally trauma, endocrine change, psychic factors, or allergy. The lesions are painful; however, the condition is self-limiting with the lesions usually healing in 10 to 14 days without leaving scars. Recurrent aphthous ulcerative lesions are similar to the ulcerative herpes simplex lesions except that the herpes lesions can also occur on the attached gingiva.

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Figure 1-10. Recurrent aphthous ulcers.

NOTE: The formation of ulcers on movable mucosal surfaces is extremely painful to the affected individual. This condition can cause difficulty in eating. The patient must maintain normal nutrition and oral health habits to limit bacteria formation.

1-47. ERYTHEMA MULTIFORME (Figure 1-11)

Erythema multiforme is an acute inflammatory condition that is easily observed because of a redness of the mucosa or the skin. It occurs in many forms on various parts of the body. Young adults are most commonly affected. The oral mucous membranes are frequently involved, including vesicle rupture that leaves painful oral ulcerations. The lips often exhibit crusted ulcerative lesions. Lesions appear rapidly (within 10 to 14 days) and persist several days or longer. The symptoms are treated, with spontaneous remissions occurring. Recurrence is common. If areas other than the skin and the mucous membranes are involved (such as the eye or the genitalia), the possibility of a syndrome complex exists.

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Figure 1-11. Erythema multiforme.

NOTE: Raw, easily bleeding gingival tissues may represent an allergic response. In this patient, a pseudomembrane has developed over the gingiva. Lack of normal oral function and decreased oral cleansing due to extreme discomfort allowed this buildup of ulcerative tissue.


a.  Common Symptoms and Causes. The allergic condition called angioneurotic edema may be related to food allergy, hypersensitivity, local infection, and endocrine or emotional disturbances. The characteristic symptom is rapid swelling of the affected tissue in 5 to 30 minutes with itching and burning sensation present. The areas most commonly involved are the skin about the eyes and chin, the lips, and the tongue. A major concern is the potential for laryngeal edema and airway compromise. The symptoms are treated.

b.  Adverse Reaction to Drug Absorption. Ingestion of certain drugs by individuals having an idiosyncrasy or intolerance to them may result in the allergic manifestations referred to as stomatitis medicamentosa. The signs in the mouth vary from a sensitive erythema (redness) to an ulcerative stomatitis or gingivitis. If withdrawal of the suspected drug is followed by disappearance of the lesions, it is evidence of its causal relationships. Therefore, treatment consists of identification and elimination of the drug causing the lesions.

c. Adverse Reaction to Contact With Drugs. While the lesions of stomatitis medicamentosa are the result of absorption of drugs, the lesions of stomatitis venenata are due to the direct contact with a drug or a material. Causative agents of stomatitis venenata may be topical medications, dentifrices, or mouthwashes. Intraoral signs may vary from a sensitive erythema (redness) to an ulceration. Treatment consists of elimination of the causative agent, local symptomatic care, or use of a mild antibacterial agent to minimize secondary infection of an ulceration.

1-49. LICHEN PLANUS (Figure 1-12)

Lichen planus is a common inflammatory disease that is observed frequently on oral mucosa. Oral lesions appear on adults as a lacy network of slender white lines, primarily on the buccal mucosa. Initiating factors may be herpes simplex, various bacterial and fungal agents, drugs (penicillin and barbiturates), vaccinations, or radiation and chemotherapy. On the skin, lichen planus is observed as a bilateral symmetrical area on the flexor muscle surfaces of the wrists and lower leg. Lichen planus may exist in various oral forms: erosive, vesicular, or hypertrophic (increase in growth through cell size, not number). The symptoms are treated.

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Figure 1-12. Lichen planus.

NOTE: The oral buccal mucosa is a common site for lichen planus. The picture shows the erosive form of lichen planus in which can be seen the typical lacy network of slender white lines on the mucosal surface.)

1-50. LEUKOPLAKIA (Figure 1-13)

Leukoplakia is a clinically descriptive term defining a white plaque. The white plaque is observed as irregular, thickening of the outer layers of the mucosa, a dullwhite-to-gray color, variable size, and with very little pain unless ulceration and secondary infection have developed. The predominate oral cause is commonly associated with chronic irritation or trauma, such as might result from ill-fitting dentures, cheekbiting, oral use of tobacco, or malpositioned or rough tooth surfaces. These areas are generally discovered by the dentist on routine examination, the patient being unaware of their existence. The condition may precede development of a malignant tumor. For this reason, early diagnosis and treatment is important. Leukoplakia resembles other conditions that may affect the oral mucosa. Therefore, diagnosis must be based upon microscopic examination of cellular changes within the involved tissues. Tissue specimens are prepared for examination by a procedure called biopsy. Once a definitive diagnosis has been made, the treatment of choice may be removal of the lesion.

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Figure 1-13. Leukoplakia.

NOTE: This white plaque has formed in an area commonly associated with denture wear. Any area of leukoplakia that does not return to normal within 10 to 14 days after removal of the cause of irritation must be biopsied to confirm a benign cellular change.


Moniliasis of the oral mucosa membranes, also called candidiasis or thrush, is a surface infection resulting from a yeast-like fungus, Candida albicans. The lesion appears as deposits of pearly-white, roughened-surface plaque, which leaves a raw, red, painful surface when scraped off. Its treatment involves prescribing antifungal drugs. When natural resistance is lowered, this infection may appear and grow. Because it takes advantage of such conditions, moniliasis is known as an opportunistic infection. It may affect debilitated adult patients, infants, or patients receiving prolonged therapy with antibiotics or corticosteroids. In addition, moniliasis may be indicative of AIDS (acquired immunodeficiency syndrome). AIDS results from the human immunodeficiency virus (HIV).

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Figure 1-14. Moniliasis.

NOTE: In this example, the yeast-like, white patches of the fungus Candida albicans can be clearly identified on the roof of the mouth.)


Localized areas of inflammation associated with dentures can result from a number of factors. They may result from occlusal disharmonies, damage to the denture base or metal framework because of careless handling, or certain tissue changes. The mucous membrane beneath the denture becomes inflamed. If it is not remedied, this chronic irritation may result in hyperplasia of the oral mucosa. Hyperplasia (an increased growth of normal cells) caused by irritation at the border of the denture takes the form of long folds of excess tissue along the denture border. These folds are called epulis fissuratum. Irritation of the palate may result in the development of numerous papillae, a condition called inflammatory papillary hyperplasia. Treatment consists of reduction of the inflammatory component and surgical removal of any hyperplastic tissue. Prostheses correction is necessary to prevent recurrence.


Cheilitis is inflammation affecting the lips. Angular cheilitis usually begins as redness and peeling of the skin at the angles (corners) of the mouth. As the condition continues, cracks occur in the skin and mucous membranes at the commissure (corners) of the lips. This condition is usually caused by infection with Candida albicans. Other factors may also contribute to the lesions. These include vitamin B complex deficiency and decreased vertical dimension associated with inadequate dentures. Angular cheilitis is also a frequent finding in patients who have been infected with the human immunodeficiency virus (HIV).

1-54. AMALGAM TATTOO (Figure 1-15)

Small, pigmented areas are common in the oral mucosa and are generally associated with tissue adjacent to restored teeth. During the placement of fillings, amalgam may find its way into soft tissue causing a discoloration. If clinical diagnosis can establish a definite diagnosis of amalgam tattoo, no treatment is necessary. An amalgam tattoo may be associated with the alveolar ridge or other mucosal tissue in patients without teeth. If there is a doubt concerning the diagnosis, a biopsy should be done. Pigmented soft tissue tumors are not frequently found on oral mucosa, though when found, they range from a benign freckle to malignant melanoma.

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Figure 1-15. Amalgam tattoo.

NOTE: This pigmented palatal lesion is not directly associated with the dentition. Amalgam particles may be found throughout the oral cavity. Amalgam particles can generally be identified as such on radiographs. Any questionable cause of tissue discoloration should be evaluated histologically after biopsy.


Aspirin burn is a chemical burn caused by holding aspirin tablets against the mucous membranes to relieve toothache. The treatment is usually palliative (medications are used to relieve discomfort but not to cure the lesions) and the prevention of secondary infection is considered.

1-56. NICOTINIC STOMATITIS (Figure 1-16)

The condition is caused by smoking, especially pipe-smoking. The irritation from heat and combustion products stimulates increased production of new epithelial cells resulting in hyperkeratosis (thickening of the layer of keratin on the epithelium) of the mucosal surface of the palate. The ductal openings of the minor salivary glands become inflamed, forming tiny spots, points, or depressions (a punctate appearance). Treatment requires elimination of the smoking habit.

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Figure 1-16. Nicotinic stomatitis.

NOTE: In this example, notice the spots. With elimination of the smoking habit, a return to normal might be expected. There is no documented malignant cellular change associated with this condition. However, there is likely to be some abnormality in tissue texture over a prolonged time.


Another oral lesion commonly seen in users of chewing tobacco or dip is called the snuff dipper's pouch. When the tobacco is kept in touch with oral mucosa over prolonged time, hyperkeratosis (thickening) occurs. Most tobacco dippers keep their chew in the mandibular labial vestibule, but the lesion can appear wherever the tobacco is kept. The lesion can be white-gray in color and develops deep folds of excess tissue. Treatment requires the elimination of the dipping habit. If the habit is not eliminated, the lesion can progress to cancer. A biopsy may be indicated to rule out cancer.


Fordyce's spots, or Fordyce's granules, are due to the entrapment of normally functioning sebaceous glands during development of the embryo. These spots are generally seen in the buccal mucosa in the retromolar area. There is no abnormality of the thin epithelial covering. No inflammation is present. The granules are observed as small, rounded elevations (maculopapules) of a yellowish-white color. They may occur singly (isolated) or in clusters. There is no clinical significance associated with Fordyce's spots. The granule is not harmful, and generally no treatment is indicated.

1-59 ORAL TORI (Figure 1-17)

In about one-fifth of the population, benign bony outgrowths called tori occur in the midline of the palate or on the lingual surfaces of the mandible in the region of the cuspids and bicuspids. Tori are covered with relatively thin mucosa. The names torus palatinus and torus mandibularis indicate the location of these benign bulges of excess bone. Oral tori develop slowly and do not need to be removed unless they interfere with speech, denture design, or are repeatedly irritated during normal mastication.

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Figure 1-17. Oral tori.

NOTE: Bilateral mandibular oral tori of varying sizes are frequently observed. These are within a normal variation of bone growth and no pathologic significance is associated with their presence.

David L. Heiserman, Editor

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Revised: June 06, 2015