Multiphase Bioscaffold for Integrated Regeneration of Root-Periodontium Complex

Objective: Regeneration of root and periodontium holds a promise to overcome current limitations of dental implant therapy, including its dependence upon supporting bone structure and lack of biological integration and remodeling with host alveolar bone.  Here, we develop an integrated scaffold with multiphase microstructure and spatial-delivered bioactive cues, and its potential in generating root-periodontium complex from dental stem/progenitor cells is tested in vitro.

Method: Polycarprolactione (PCL)-hydroxylapatite (HA) (90:20wt%) scaffolds were fabricated 5×5×3mm³) using 3D printing per our prior works.  The scaffolds consisted of three phases: A) 100µm microchannels with 2.25mm in width, B) 600µm microchannels with 500µm in width, and C) 300µm microchannels with 2.25mm in width.  Phases A, B, and C were designed to guide formation of dentin/cementum, periodontal ligament (PDL), and alveolar bone, respectively.  To promote cell differentiation, PLGA microspheres encapsulated with amelogenin, CTGF, and BMP2 were incorporated in phase A, B, and C of the scaffolds, respectively.  Upon 4-wk culture with human dental pulp stem/progenitor cells (DPSCs), periodontal ligament stem/progenitor cells (PDLSCs), or alveolar bone stem/progenitor cells (ABSCs) in vitro, multiphase tissue formation in the scaffolds was evaluated by multitude of assays.

Result: Immuno-/histomorphometric analysis demonstrated that multiphase scaffold microstructure with spatial-delivered bioactive cues successfully generated multiphase tissues consisting of collagen I-rich fibrous matrix (Phase B) sandwiched between mineralized regions (Phase A and C). DSP-positive mineralized structure in Phase A was highly dense and polarized in comparison with that of Phase C.  DPSCs were superior to the other cell types in mineralization, whereas PDLSCs yielded highly aligned fibrous structure as compared to the other cell types. 

Conclusion: Our findings suggest a strategy to recapitulate the multiple tissues of the root-periodontium from dental stem/progenitor cells.  Multiphase scaffolds with spatially delivered bioactive cues may serve as an efficient tool for root-periodontium regeneration.