FIGURE 117.3 An eruption cyst associated with an erupting primary central incisor Eruption Cysts Eruption cysts arise from the pre-eruptive dental sac and appear as a swelling of the alveolar ridge They are associated with the eruption of primary ( Fig 117.3 ) and permanent teeth Occasionally, they fill with blood and may be termed eruption hematomas ( Fig 117.4 ) Treatment is unnecessary because the erupting tooth usually emerges within several days If treatment becomes necessary due to the size of the lesion, excision of the overlying soft tissue to expose the erupting tooth eliminates the problem Aphthous Stomatitis Aphthous stomatitis is the most common disease of the oral mucosa and may affect 20% or more of the population These painful, shallow, circular ulcerations are distinctive because of their size (2 to mm), distribution, and recurrence Clinically, the floor of the ulceration is yellowish, with a sharply defined red margin Aphthae affect only nonkeratinized areas of the mouth, such as the