Morphogenetic behavior of periodontium on inorganic implant materials: An experimental study of canines

Abstract

Periodontal ligament derived cells have the potential to regenerate all the components of the periodontium on the surface of inorganic implants, as well as on dentin. This suggests the hypothesis that the nature of the material affects the migration, proliferation, and differentiation of the progenitor cells for periodontium formation. To clarify this hypothesis, we evaluated the material-specific morphogenetic potential of periodontium-derived cells using an animal model for inducing cell migration from the functioning periodontium onto bioactive (hydroxyapatite, HA) and bioinert (titanium alloy, TA) material. Histologically, total periodontium including calcified cementum-like tissue only formed on HA and not on TA. Morphometrically, however, the length of fibrous connective tissue formed on HA was the same as on TA. This suggests that the bioactivity of the material does not affect the migration of periodontium-derived cells but strongly influences cell differentiation.

Osteostimulatory effect of bone grafts on fibroblast cultures

“…Fibroblasts can be induced to form calcified tissue by a number of factors such as bone morphogenic protein-2[ 5 ] and hydroxyapatite (HA). [ 6 ] Under these conditions, fibroblasts produce a number of proteins common to bone and cementum including osteopontin,[ 7 ] bone sialoprotein[ 7 ] and alkaline phosphatase (ALP). [ 8 ] Incidentally, fibroblasts express ALP,[ 9 10 ] a marker for developing bone cells.…”

A simple cell motility assay demonstrates differential motility of human periodontal ligament fibroblasts, gingival fibroblasts, and pre-osteoblasts

“…Fibroblasts of the PDL can be induced to form calcified tissue by a number of factors, including bone morphogenic protein-2 (Takiguchi et al 1999), dexamethasone (Kuru et al 1999), and hydroxyapatite (Urabe et al 2000). Under these conditions, PDL fibroblasts produce a number of proteins common to bone and cementum, including osteopontin (Strayhorn et al 1999), bone sialoprotein (Strayhorn et al 1999), and alkaline phosphatase (Alliot-Licht et al 1997).…”

Partial generation of periodontal ligament on endosseous dental implants in dogs

“…Previous attempts at the generation of a PDL on dental implants have involved placement of fixtures in close proximity to a retained root tip (Buser et al 1990; Urabe et al 2000). This protocol has involved partial extraction of a tooth with intentional root fracture, followed by implant placement in contact to the root tip.…”