title: Immunocytochemical characterization of ectopic enamel deposits and cementicles in human teeth.
abstract: Despite the relative frequency and clinical relevance of radicular enamel deposits and cementicles, their etiology and nature are unknown. The purpose of the present study was therefore to evaluate the presence and distribution of mineralization-associated non-collagenous matrix proteins (NCPs) in various types of root-associated ectopic mineralizations. Human teeth were processed for embedding in epoxy or acrylic resins. Tissue sections were incubated with antibodies to amelogenins (AMEL), bone sialoprotein (BSP), and osteopontin (OPN). Radicular enamel deposits contained residual organic matrix that labeled for AMEL. In contrast, BSP and OPN were not detected in the residual enamel matrix, they were found in the cementum deposited on its surface as well as in collagen-free cementicle-like structures in the adjacent periodontal ligament. True cementicles consisted of a collagenous matrix intermixed with a non-collagenous ground substance. Labeling for BSP and OPN was mainly associated with the interfibrillar ground substance. No immunoreactivity for AMEL was detected in cementicles. These data indicate that ectopic enamel deposits on the root retain a high amount of AMEL, whereas cementicles contain BSP and OPN, two NCPs typically found in bone and cementum. These NCPs may, like in their normal tissue counterparts, play a role in the mineralization process.
authors.affiliation: Department of Periodontology and Fixed Prosthodontics, School of Dental Medicine, University of Berne, Berne, Switzerland. dieter.bosshardt@zmk.unibe.ch
authors.forename: Dieter D
authors.initials: DD
authors.lastname: Bosshardt
authors.forename: Antonio
authors.initials: A
authors.lastname: Nanci
mesh_terms: D053523:Amelogenin; D003739:Dental Cementum / Q000002:abnormalities* / Q000737:chemistry / Q000648:ultrastructure; D003743:Dental Enamel / Q000002:abnormalities* / Q000737:chemistry / Q000648:ultrastructure; D003746:Dental Enamel Proteins / Q000032:analysis; D016326:Extracellular Matrix Proteins / Q000032:analysis; D006801:Humans; D007150:Immunohistochemistry; D058574:Integrin-Binding Sialoprotein; D008854:Microscopy, Electron; D053495:Osteopontin; D010513:Periodontal Ligament / Q000002:abnormalities; D012795:Sialoglycoproteins / Q000032:analysis; D014071:Tooth Abnormalities / Q000473:pathology*; D014074:Tooth Calcification; D014092:Tooth Root / Q000002:abnormalities*
chemical_list: D053523:Amelogenin; D003746:Dental Enamel Proteins; D016326:Extracellular Matrix Proteins; C546871:IBSP protein, human; D058574:Integrin-Binding Sialoprotein; C506895:SPP1 protein, human; D012795:Sialoglycoproteins; D053495:Osteopontin