An eruption cyst, sometimes known as an eruption hematoma, is a common, localized swelling that appears on the gum tissue just before a new tooth emerges into the mouth. It is a benign condition resulting from fluid accumulation between the crown of an erupting tooth and the soft tissue covering it.
Identifying an Eruption Cyst
An eruption cyst presents as a smooth, dome-shaped swelling on the gums, directly over the site where a primary or permanent tooth is expected to appear. This soft tissue lesion is often translucent or may display a bluish, purplish, or reddish-brown hue due to the presence of blood, which is why it is also called an eruption hematoma. The color variation simply indicates whether the trapped fluid is clear or mixed with a small amount of blood from the eruption process.
The cyst forms when fluid collects in the space between the tooth’s crown and the dental follicle, the tissue sac that surrounds the developing tooth. It is most frequently observed in children ages six to nine as permanent teeth, particularly the first permanent molars, begin to erupt.
The Typical Timeline for Resolution
The vast majority of eruption cysts are self-resolving and require no active medical intervention. As the tooth continues its upward movement, the mechanical pressure against the overlying gum tissue causes the cyst membrane to rupture.
This rupture allows the fluid to drain and the swelling to subside, with the tooth then emerging through the now-open gum tissue. In most cases, the cyst lasts only a few days to a couple of weeks, resolving entirely as soon as the tooth breaks through the gum line.
If the underlying tooth is erupting more slowly than usual, the eruption cyst may persist for a longer period. For instance, in rare cases of a slow-growing or impacted tooth, the cyst might remain for up to four months. In these longer-duration scenarios, the recommended approach is typically observation and patience, as the body is often still working to complete the natural process.
When is Dental Intervention Necessary
While the “wait and see” approach is appropriate in most situations, there are specific signs that indicate the need for a dental evaluation. A dentist should be consulted if the cyst fails to resolve after a few weeks, or if it causes significant, persistent pain that interferes with eating or drinking. These symptoms suggest the cyst may be delaying the tooth’s progress or causing unnecessary discomfort.
Signs of a possible secondary infection also require prompt professional attention, including fever, pus discharge, or swelling that spreads beyond the immediate cyst area. In the rare instance that the cyst is particularly dense, large, or significantly impedes the tooth’s eruption, a minor procedure may be necessary.
This procedure, sometimes called marsupialization, involves making a small incision in the cyst to allow the fluid to drain and create an opening for the tooth to emerge. This action is generally a straightforward way to encourage the tooth to continue its natural path into the mouth.