ELEVATED LESIONS

Numerous types of lesions are above the surface of the mucosa. Two of the most common are discussed below.

Vesicles \A small elevation that contains fluid. Most of these lesions in the oral cavity rupture, leaving superficial ulcers.

Hematoma \A localized collection of blood that escaped from blood vessels due to trauma. It is well-defined and with time, changes to a dark color.

NONELEVATED LESIONS

Two common lesions of the oral mucosa in this category are as follows:

Petechiae\Round pinpoint, nonraised, purplish-red spots, caused by mucosal or dermal hemorrhage.

Ecchymoses\Large, purplish-red areas caused by blood under the skin or mucosa; turns to a blue or yellow color.

DISEASES OF THE TEETH

Teeth become diseased for many reasons. We will look at some of the more common diseases found in teeth such as impaction, attrition, abrasion, erosion, resorption, and dental caries.

IMPACTION

An impaction (fig. 5-2) is the condition in which a tooth is blocked by a physical barrier, usually teeth or bone. A tooth may not erupt in the normal time period if an impaction occurs. Some of the causes of impacted teeth are:

Movement of the erupting tooth into a horizontal, vertical, or other abnormal position.

Early loss of deciduous teeth.

Insufficient jaw space, abnormally large tooth crowns, supernumerary or other teeth in a dental arch.

ABRASION AND ATTRITION

Attrition (fig. 5-3) is the loss of substance of a tooth from a wearing away process caused by teeth against teeth. Whereas, abrasion results in the loss of tooth structure secondary to the action of external agents.

In attrition, wear involves aspects on the incisal, occlusal, and interproximal surfaces of the teeth and is considered a normal or gradual loss of tooth substance because of the mastication of food. Causes of occlusal attrition can result from bruxism (grinding of teeth), chewing of tobacco or gum, or other oral habits that involve mastication.

In abrasion, one or more teeth may show wear, generally brought about by improper toothbrushing,

Figure 5-2.\Impaction.

Figure 5-3.\Attrition.

biting foreign objects such as a pipestem, thread, or bobby pins. Other mechanical actions such as a poorly fitted clasp of partial dentures or acid from food debris can cause abrasion.

EROSION

Erosion is a loss of tooth substances from a chemical process that does not involve bacteria. It occurs usually on the facial surfaces at the gingival third of the crown and often involves the maxillary incisors. The enamel and dentin on the floor of the lesion are smooth, hard, and glistening. Some types of lesions are called idiopathic erosion because the factors producing this condition are unknown or may occur from a known acid source such as people who have bulimia (who vomit frequently).

During the early stages of erosion, the eroded areas are very sensitive to heat and cold, acid foods, and toothbrushing, but sensitivity may decrease when secondary dentin is formed.