Ultrasonic activation of irrigants increases growth factor release from human dentine.
OBJECTIVE
Bioactive proteins are sequestered in human dentine and play a decisive role in dental pulp regeneration and repair. They can be released and exposed on the dentine surface by acids, but also chelators, such as ethylenediaminetetraacetic acid (EDTA). The objectives of this study were (i) to evaluate whether ultrasonic activation of irrigants in the root canal will promote growth factor release from dentine and (ii) to collect bioactive proteins in a physiological solution.


METHODS
Human dentine disks underwent irrigation with and without ultrasonic activation. The protocols included treatment by either a single or two consecutive steps with 10 % EDTA and phosphate-buffered saline (PBS), where each sample was treated three times. To mimic clinical conditions, selected irrigation regimens were applied to root canals of extracted human teeth after preparation. Amounts of transforming growth factor β1 (TGF-β1) in solution were quantified using enzyme-linked immunosorbent assays. Nonparametric statistical analysis was performed to compare different groups as well as repetitions within a group (Mann-Whitney U test, α = 0.05). Additionally, morphological changes of dentine surfaces were visualized by scanning electron microscopy (SEM).


RESULTS
TGF-β1 was not detectable after irrigation of dentine with PBS, neither with nor without ultrasonic activation. Irrigation with EDTA released TGF-β1, and ultrasonic activation of EDTA enhanced this effect. However, preceding EDTA conditioning enabled the release of bioactive proteins into PBS solution. Similar results were observed in dentine disks and root canals. Visualization of dentine surfaces after different treatment revealed superficial erosion after ultrasonic activation irrespective of the irrigant solution, but different degrees of exposure of organic substance.


CONCLUSIONS
Ultrasonic activation enhances growth factor release from human dentine. Bioactive proteins can be isolated in physiological solvents and may act as autologous supplements for regenerative endodontic treatment or pulp tissue engineering.


CONCLUSIONS
Autologous growth factors from human dentine can advance treatment strategies in dental pulp tissue engineering.
Department of Conservative Dentistry and Periodontology, University Hospital Regensburg, Franz-Josef-Strauß-Allee 11, 93053, Regensburg, Germany. matthias.widbiller@ukr.de.
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Widbiller
Department of Conservative Dentistry and Periodontology, University Hospital Regensburg, Franz-Josef-Strauß-Allee 11, 93053, Regensburg, Germany.
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Eidt
Department of Conservative Dentistry and Periodontology, University Hospital Regensburg, Franz-Josef-Strauß-Allee 11, 93053, Regensburg, Germany.
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Hiller
Department of Conservative Dentistry and Periodontology, University Hospital Regensburg, Franz-Josef-Strauß-Allee 11, 93053, Regensburg, Germany.
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Buchalla
Department of Conservative Dentistry and Periodontology, University Hospital Regensburg, Franz-Josef-Strauß-Allee 11, 93053, Regensburg, Germany.|School of Dental Medicine, University of Bern, Freiburgstrasse 7, CH-3010, Bern, Switzerland.
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Schmalz
Department of Conservative Dentistry and Periodontology, University Hospital Regensburg, Franz-Josef-Strauß-Allee 11, 93053, Regensburg, Germany.
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Galler
D003804:Dentin / Q000378:metabolism*; D004492:Edetic Acid / Q000494:pharmacology; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D066298:In Vitro Techniques; D008855:Microscopy, Electron, Scanning; D012388:Root Canal Irrigants / Q000494:pharmacology*; D007507:Therapeutic Irrigation; D053773:Transforming Growth Factor beta1 / Q000378:metabolism*; D014465:Ultrasonics
D012388:Root Canal Irrigants; D053773:Transforming Growth Factor beta1; D004492:Edetic Acid
Dentine; Ethylenediaminetetraacetic acid; Regenerative endodontic procedure; Tissue engineering; Transforming growth factor beta1; Ultrasonic activation