Growth Factor Liberation and DPSC Response Following Dentine Conditioning.
Liberation of the sequestrated bioactive molecules from dentine by the action of applied dental materials has been proposed as an important mechanism in inducing a dentinogenic response in teeth with viable pulps. Although adhesive restorations and dentine-bonding procedures are routinely practiced, clinical protocols to improve pulp protection and dentine regeneration are not currently driven by biological knowledge. This study investigated the effect of dentine (powder and slice) conditioning by etchants/conditioners relevant to adhesive restorative systems on growth factor solubilization and odontoblast-like cell differentiation of human dental pulp progenitor cells (DPSCs). The agents included ethylenediaminetetraacetic acid (EDTA; 10%, pH 7.2), phosphoric acid (37%, pH <1), citric acid (10%, pH 1.5), and polyacrylic acid (25%, pH 3.9). Growth factors were detected in dentine matrix extracts drawn by EDTA, phosphoric acid, and citric acid from powdered dentine. The dentine matrix extracts were shown to be bioactive, capable of stimulating odontogenic/osteogenic differentiation as observed by gene expression and phenotypic changes in DPSCs cultured in monolayer on plastic. Polyacrylic acid failed to solubilize proteins from powdered dentine and was therefore considered ineffective in triggering a growth factor-mediated response in cells. The study went on to investigate the effect of conditioning dentine slices on growth factor liberation and DPSC behavior. Conditioning by EDTA, phosphoric acid, and citric acid exposed growth factors on dentine and triggered an upregulation in genes associated with mineralized differentiation, osteopontin, and alkaline phosphatase in DPSCs cultured on dentine. The cells demonstrated odontoblast-like appearances with elongated bodies and long extracellular processes extending on dentine surface. However, phosphoric acid-treated dentine appeared strikingly less populated with cells, suggesting a detrimental impact on cell attachment and growth when conditioning by this agent. These findings take crucial steps in informing clinical practice on dentine-conditioning protocols as far as treatment of operatively exposed dentine in teeth with vital pulps is concerned.
Oral and Biomedical Sciences, School of Dentistry, College of Biomedical and Life Sciences, Cardiff University, Cardiff, UK sadaghianil@cf.ac.uk.
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Sadaghiani
School of Dentistry, College of Biomedical and Life Sciences, Cardiff University, Cardiff, UK.
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HB
Gleeson
Oral and Biomedical Sciences, School of Dentistry, College of Biomedical and Life Sciences, Cardiff University, Cardiff, UK.
S
S
Youde
Oral and Biomedical Sciences, School of Dentistry, College of Biomedical and Life Sciences, Cardiff University, Cardiff, UK.
R J
RJ
Waddington
Learning and Scholarship, School of Dentistry, College of Biomedical and Life Sciences, Cardiff University, Cardiff, UK.
C D
CD
Lynch
Oral and Biomedical Sciences, School of Dentistry, College of Biomedical and Life Sciences, Cardiff University, Cardiff, UK.
A J
AJ
Sloan
D000180:Acrylic Resins / Q000494:pharmacology; D019343:Citric Acid / Q000494:pharmacology; D003782:Dental Pulp / Q000166:cytology* / Q000187:drug effects / Q000502:physiology; D003804:Dentin / Q000187:drug effects / Q000502:physiology*; D004492:Edetic Acid / Q000494:pharmacology; D015870:Gene Expression / Q000187:drug effects; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000378:metabolism*; D010756:Phosphoric Acids / Q000494:pharmacology; D013234:Stem Cells / Q000166:cytology / Q000187:drug effects* / Q000502:physiology; D014016:Tissue Conditioning, Dental / Q000009:adverse effects
D000180:Acrylic Resins; D036341:Intercellular Signaling Peptides and Proteins; D010756:Phosphoric Acids; D019343:Citric Acid; C006903:carbopol 940; D004492:Edetic Acid; C030242:phosphoric acid
cell differentiation; dentinogenesis; esthetic dentistry; gene-expression; pulp biology; stem cell(s)