The characterization of periodontal fibroblasts (PF) is essential in order to find out the specific role that it has to play in the regeneration of the periodontium. Previous studies have revealed that mineralization supplements have the ability to differentiate rat and human periodontal ligament cells.
In vivo studies have also shown that the periodontopathic bacteria have direct effects on the progression of periodontal disease. However, less is known about the relationships of mineralization supplements and the extracts derived from periodontopathic bacteria to
in vitro culture models on PF. Objectives: This study was undertaken to determine the combined effects of mineralization supplements and periodontopathic bacterial extracts on PF as to alkaline phosphatase (ALP) activity, collagen content and morphology. Methods: Mineralization supplements of known concentrations have been used; 10 mM
b-glycerophosphate(
b-GP), 50 µg ascorbic acid (AA), 10
-7M dexamethasone (Dex). They were tested singly or in combination to cultured PF. They were subjected for 24 to 30 day incubation periods in order to observe nodule formation. Then, these periodontopathic bacterial extracts (P.g., B.f., T.d.) and E.coli (negative control) were added and incubated for 24 hours to the cultured PF with mineralization supplements. Results: Increasing ALP activity and collagen content were observed for PF treated with Dex and AA (p<0.0001). There was a decreasing effect in ALP activity on Dex-AA-treated PF upon application of extracts derived from periodontopathic bacteria as compared to the control groups; P.g.(p<0.01), B.f.(p<0.00008), T.d.(p<0.0003), E.coli (p<0.001). Conclusions: These findings indicate that Dex-AA can alter the level of ALP activity and amount of collagen content. Moreover, it appears to be an effective agent to initiate differentiation for cells with osteoblastic phenotypes. The extracts from periodontopathic bacterial seems to have inhibitory effects on the ability of PF to undergo differentiation.