Methods: 1mm thick slices of human dentine were treated with PBS, 10% EDTA, 10% citric acid, 37% phosphoric acid and 0.02M Ca(OH)2 for 5 and 10 minutes. Gold immunolabelling and ELISA examined growth factor exposure and release. A clonal DPSC population were seeded on treated dentine at 3.5x104 cells/cm2 and on plastic (controls) and cultured for up to 14 days prior to visualisation and morphological examination by SEM. Q-PCR for progenitor cell and differentiation markers (CD105, CD90, BSP, osteopontin and alkaline phosphatase) was performed following culture.
Results: 5mins treatment with all conditioning agents resulted in significant exposure of TGF-β1, BMP2 and VEGF on dentine surfaces. After 10min treatment, maximum growth factor exposure was observed in slices treated by Ca(OH)2. Highest concentrations of TGF- β1 was detected in the supernatants of EDTA. Concentrations of BMP2 and VEGF were highest following Ca(OH)2 and citric acid treatment. After 7 days culture, expression of osteopontin and alkaline phosphatase were significantly higher (P<0.05) in cells cultured on slabs treated by Ca(OH)2 and after 14 days by EDTA when compared to untreated dentine. Expression of progenitor cell markers were significantly down regulated in cells cultured on dentine 7 days following seeding.
Conclusion: Growth factors were exposed and released following dentine treatment by different clinical conditioning agents. Dentine surface treatment induced a stimulatory response in DPSCs. This may provide a useful basis for selection of dentine conditioning techniques prior to restorative procedures.