Altered passive eruption (APE):A little-known clinical situation

Abstract

Gummy smile constitutes a relatively frequent aesthetic alteration characterized by excessive exhibition of the gums during smiling movements of the upper lip. It is the result of an inadequate relation between the lower edge of the upper lip, the positioning of the anterosuperior teeth, the location of the upper jaw, and the gingival margin position with respect to the dental crown. Altered Passive Eruption (APE) is a clinical situation produced by excessive gum overlapping over the enamel limits, resulting in a short clinical crown appearance, that gives the sensation of hidden teeth. The term itself suggests the causal mechanism, i.e., failure in the passive phase of dental eruption, though there is no scientific evidence to support this. While there are some authors who consider APE to be a risk situation for periodontal health, its clearest clinical implication refers to oral esthetics. APE is a factor that frequently contributes to the presence of a gummy or gingival smile, and it can easily be corrected by periodontal surgery. Nevertheless, it is essential to establish a correct differential diagnosis and good treatment plan. A literature review is presented of the dental eruption process, etiological hypotheses of APE, its morphologic classification, and its clinical relevance.

Prevalence of Altered Passive Eruption in Orthodontically Treated and Untreated Patients

“…Few studies have evaluated the possible causes of APE. A number of factors have been proposed, such as interocclusal interference on the part of soft tissues during the eruptive phase, a certain hereditary tendency in families with individuals presenting APE, and the presence of thick and fibrotic gingival biotype that tends to migrate more slowly during the passive phase than thin gingival tissue 12,13 …”

“…Evidence to date fails to clarify the causes and mechanisms that may lead to APE, although a few studies have related such mechanisms to the morphology adopted by the coronal periodontium 12 …”

Morphology and dimensions of the dentogingival unit in the altered passive eruption

“…Many authors have investigated the causes and mechanisms that may lead to tooth eruption failure, though few studies have related such mechanisms to the morphology adopted by the coronal periodontium (8). …”

The treatment of gummy smile: integrative review of literature

“…Today, however, people often seek dental treatment for aesthetic reasons, forcing professionals to find ways of achieving more harmonious and symmetrical smiles, in order to ensure satisfactory rehabilitation. 1,2 Factors normally involved in the aesthetic consideration of a smile are related to the lips, positioning, size, shape, and teeth color, as well as the proximity between the gingival tissue and the teeth. 3,4 Other factors associated with aesthetics are related to health, tooth discoloration, morphology and suitable gingival contours, all of which are considered essential to an attractive smile.…”