Fibrin gel improves tissue ingrowth and cell differentiation in human immature premolars implanted in rats.
BACKGROUND
In pulpless immature human premolars implanted in rodents, this study investigated whether fibrin gel offered advantages over leaving the root canal empty regarding soft tissue ingrowth and cell differentiation.


METHODS
Root canals of extracted human immature premolars (n = 12) were accessed and then irrigated with 5% sodium hypochlorite followed by 17% ethylenediaminetetraacetic acid. Root canals were then either left empty or filled with a fibrin gel (n = 6 each) before being placed subcutaneously on top of the calvarial bone of rats (1 tooth per rat) for 12 weeks. After sacrifice, teeth were histologically assessed. Tissue ingrowth was quantified and compared between groups using the Mann-Whitney U test (P < .05). Cells adhering to the pulp canal wall were immunohistochemically screened for the presence of bone sialoprotein (BSP) and dentin sialoprotein (DSP).


RESULTS
More tissue grew into the pulp space when teeth were filled with fibrin gel (P < .05). The presence of fibrin gel affected not only the extent of tissue ingrowth but also tissue morphology and differentiation of cells contacting the dentinal wall. In the fibrin gel group, newly formed tissue was similar to normal pulp, constituted of inner pulp, cell-rich zone, cell-free zone, and an apparent odontoblast layer, which stained positive for BSP and DSP. Newly formed blood vessels were also more abundant compared with the initially empty root canals.


CONCLUSIONS
Under the conditions of this study, fibrin gel improved cell infiltration and cell-dentin interaction. Both are necessary for pulp tissue regeneration.
Division of Cranio-Maxillofacial and Oral Surgery and Institute for Oral Biology, University of Zürich Center for Dental Medicine, Zurich, Switzerland.
Nisarat
N
Ruangsawasdi
Department of Preventive Dentistry, Periodontology, and Cariology, University of Zürich Center for Dental Medicine, Zurich, Switzerland.
Matthias
M
Zehnder
Division of Cranio-Maxillofacial and Oral Surgery and Institute for Oral Biology, University of Zürich Center for Dental Medicine, Zurich, Switzerland. Electronic address: franz.weber@zzm.uzh.ch.
Franz E
FE
Weber
D000818:Animals; D001641:Bicuspid / Q000187:drug effects* / Q000473:pathology; D002448:Cell Adhesion / Q000187:drug effects; D002454:Cell Differentiation / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D048430:Cell Shape / Q000187:drug effects; D003782:Dental Pulp / Q000187:drug effects / Q000473:pathology; D003786:Dental Pulp Cavity / Q000187:drug effects / Q000473:pathology; D003804:Dentin / Q000187:drug effects / Q000473:pathology; D016326:Extracellular Matrix Proteins / Q000032:analysis; D005260:Female; D015718:Fibrin Tissue Adhesive / Q000494:pharmacology*; D006801:Humans; D058574:Integrin-Binding Sialoprotein / Q000032:analysis; D018919:Neovascularization, Physiologic / Q000187:drug effects; D009804:Odontoblasts / Q000187:drug effects / Q000473:pathology; D010750:Phosphoproteins / Q000032:analysis; D051381:Rats; D017207:Rats, Sprague-Dawley; D012038:Regeneration / Q000187:drug effects; D018915:Root Canal Preparation / Q000379:methods; D012795:Sialoglycoproteins / Q000032:analysis; D040521:Subcutaneous Tissue / Q000601:surgery; D054457:Tissue Scaffolds; D019553:Tooth, Nonvital / Q000503:physiopathology*; D000099311:Dentin Sialophosphoprotein
D016326:Extracellular Matrix Proteins; D015718:Fibrin Tissue Adhesive; D058574:Integrin-Binding Sialoprotein; D010750:Phosphoproteins; D012795:Sialoglycoproteins; D000099311:Dentin Sialophosphoprotein
Pulp; regeneration; revascularization