Abstract
The calcifications in dental pulp appeared to consist of discrete, smooth-surfaced laminated denticles and irregularly shaped, non-laminated denticles, together with a diffuse calcification characterized by small foci scattered throughout the fibrous pulp matrix. Calcification appeared to be initiated in relation to the interfibrillar matrix, collagen fibres and connective tissue cells. In each case the inorganic phases showed a distinct morphology; electron diffraction suggested hydroxyapatite. Both the laminated and non-laminated denticles had an organic matrix consisting of collagen fibres together with a background of electron dense material between the fibres. The laminated denticles appeared to grow by the addition of layers of collagen to the surface, leaving an uncalcified border zone which gradually calcified. The matrix of the non-laminated denticles was formed by the collagen fibres orientated in the long axis of the pulp, and no border zone was present. These denticles grew by the addition of mineral to the adjacent matrix fibres. Some small denticles did not have a collagen fibre matrix, but an electron-dense granular matrix was present. One such denticle was being resorbed by a giant multi-nucleated cell. The non-laminated denticles contained areas devoid of fibrils in which the crystallites were larger but gave a diffraction pattern indicative of hydroxyapatite. Between the matrix fibres in diffuse calcification an electron dense granular material was present.
Résumé
Les calcifications de la pulpe dentaire semblaient constituer par de petits pulpolithes lamellaires, à surfaces lisses, par des pulpolithes non lamellaires, à contours irréguliers, ainsi que par une calcification diffuse, constituée de petits foyers disséminés dans la matrice fibreuse pulpaire. La calcification semble débuter au niveau de la matrice interfibrillaire, du collagène et des cellules conjonctives. Dans chaque cas, les phases inorganiques ont un aspect morphologique distinct: la diffraction électronique semble indiquer la présence d’hydroxyleapatite. Les 2 types de pulpolithes ont une matrice organique constituée de collagène et d’un matériel dense aux électrons, situé entre les fibres. Les pulpolithes lamellaires semblent s’accroitre par adjonction de couches de collagène à leur surface, laissant subsister un rebord non calcifié, que se calcifie progressivement. La matrice des pulpolithes non lamellaires est formée de fibres de collagène orientées le long de l’axe de la pulpe et aucun rebord n’est visible. Ces pulpolithes s’accroissent par dépôt de minéral aux fibres de la matrice adjacente. Certains petits pulpolithes n’ont pas de matrice collagénique, mais une matrice granulaire dense aux électrons. Un de ces pulpolithes est résorbé par une cellule géante multinucléée. Les pulpolithes non-lamellaires présentent des zones afibrillaires où les cristaux sont plus larges et donnent des clichés de diffraction électronique d’hydroxyleapatite. Entre les fibres de la matrice des calcifications diffuses, un matériel granulaire dense est visible.
Zusammenfassung
Die Verkalkungen in Zahnpulpa scheinen zu bestehen aus: getrennten, lamellenförmigen Dentikeln mit glatter Oberfläche und unregelmäßig geformten, nicht-lamellenförmigen Dentikeln, zusammen mit einer diffusen Verkalkung, welche durch kleine Foci charakterisiert ist, die in der ganzen fibrösen Pulpamatrix verteilt sind. Die Verkalkung schien durch die inter-fibrilläre Matrix, die Kollagenfasern und die Bindegewebszellen hervorgerufen zu werden. Bei jedem Fall zeigten die anorganischen Phasen eine ausgeprägte Morphologie; die Elektronendiffraktion deutete auf Hydroxyapatit. Lamellenförmige und nicht-lamellenförmige Dentikel besaßen eine organische Matrix, welche aus Kollagenfasern und elektronendichtem Material zwischen den Fasern bestand. Die lamellenförmigen Dentikel schienen zu wachsen, indem sie Kollagenschichten auf der Oberfläche anfügten, wobei eine Randzone zuerst unverkalkt blieb und dann allmählich verkalkte. Die Matrix der nicht-lamellenförmigen Dentikel wurde durch die Kollagenfasern der Längsachse der Pulpa gebildet, und eine Randzone war nicht vorhanden. Diese Dentikel wuchsen, indem den angrenzenden Matrixfasern Mineral zugefügt wurde. Einige kleine Dentikel wiesen keine Kollagenfaser-Matrix auf, aber eine elektronendichte granuläre Matrix wurde festgestellt. Ein solcher Dentikel wurde von einer vielkernigen Riesenzelle resorbiert. Die nicht-lamellenförmigen Dentikel enthielten Zonen ohne Fibrillen, in welchen die Kriställchen größer waren, aber ein Diffraktionsmuster zeigten, welches auf Hydroxyapatit hindeutete. Zwischen den Matrixfasern in der diffusen Verkalkung wurde ein elektronendichtes granuläres Material festgestellt.
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Appleton, J., Williams, M.J.R. Ultrastructural observations on the calcification of human dental pulp. Calc. Tis Res. 11, 222–237 (1973). https://doi.org/10.1007/BF02547221
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DOI: https://doi.org/10.1007/BF02547221