Desmosomes are molecular complexes of cell adhesion proteins and linking proteins that attach the cell surface adhesion proteins to intracellular keratin cytoskeletal filaments. The cell adhesion proteins of the desmosome, desmoglein and desmocollin, are members of the cadherin family of cell adhesion molecules. They are transmembrane proteins that bridge the space between adjacent epithelial cells by way of homophilic binding of their extracellular domains to other desmosomal cadherins on the adjacent cell. Both have five extracellular domains, and have calcium-binding motifs.
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This article has been cited by other articles in PMC. Abstract Objetives: This study define altered passive eruption APE and evaluate the morphology of the dentogingival unit. Material and Methods: individuals subjected to clinical examination and parallel profile radiography of the upper central incisor. Statistical analysis confirms two morphological patterns of APE. Key words:Altered passive eruption ape , radiographic exploration, dentogingival unit dgu , gingival thickness, plastic periodontal surgery, surgical crown lengthening.
Introduction The dentogingival unit DGU has been described as a functional unit composed of the epithelial attachment and connective tissue attachment of the gingiva — both of which afford biological protection 1.
Gargiulo et al. These authors described the relationships and dimensions of the DGU components in humans, and their results show the epithelial attachment to measure 0. In humans this distance is 2. The DGU is habitually located close to the cementoenamel junction, the gingival margin slightly covering the limits of the dental crown 5.
Different physiological situations do not exhibit this morphological disposition, however, and the gingival margin tends to occupy a much more incisal position — thus giving rise to short clinical crowns.
This variation in habitual morphology involving a more coronal periodontium has been referred to as altered passive eruption APE or delayed passive eruption 6. Tooth eruption comprises two phases 7 : an active eruption phase which causes the tooth to emerge into the oral cavity, and a passive eruption phase involving apical migration of the soft tissues covering the crown of the tooth.
From the current perspective, the active phase of eruption is defined by emerging motion of the tooth in the occlusal direction until the tooth reaches the occlusal plane of its antagonist. This vertical motion causes the gums to displace along with the crown. With the passive eruption phase, the gums migrate in the apical direction, with gradual exposure of the crown of the tooth and final stable localization of the DGU at cervical level.
However, even if this pathogenic hypothesis of APE were accepted, the literature fails to clarify the circumstances causing arrested tooth eruption and conditioning DGU morphology. 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 purpose of the study was to further knowledge of the morphological features of APE at DGU level, with the following specific aims: a Definition of APE based on gingival overlap on the anatomical crown; b The determination of possible differences at DGU level between teeth with and without APE; and c Confirmation of the existence of different morphological patterns of APE.
Material and Methods A total of individuals participated in the study. The selection focused on ensuring the maximum inclusion of subjects with upper anterior teeth presenting clinical evidence of APE.
The protocol of the study was accepted by the Committee on Ethics in Human Research of the University of Valencia and written informed consent was granted from all subjects. Two types of exploration were carried out in second sextant: clinical, and one parallel profile radiography PPRx on the maxillary left central incisor tooth The same examiner F. Clinical exploration Two subjective criteria were contemplated for the clinical diagnosis of APE: a excessively flattened gingival festooning, and b a disproportionate papilla base width in relation to the height reached by the tip.
The APE was diagnosed when these criteria were met in the context of a patient with a clinically apparent short dental crown Fig.
Morphology and dimensions of the dentogingival unit in the altered passive eruption