Fig 1.
Structure of matrices for engineered lamina propria.
Scanning electron micrographs of A) decellularized dermis (DD), B) electrospun collagen (ES), and C) collagen gels. Decellularized dermis was comprised of collagen fiber bundles woven into a crosshatched pattern (A), whereas electrospun collagen was nonwoven with larger individual collagen fibers. Collagen gels were dense in structure, containing smaller collagen fibers. Note the scale bar on the inset is 500 nm versus 5 μm in the insets for DD and ES matrices.
Fig 2.
Lamina propria engineered with different scaffold systems.
Multiple scaffold systems were considered for the development of human engineered gingiva including decellularized dermis (DD), electrospun collagen (ES), collagen gels cast over a membrane (Gel) and collagen gels cast into a standard culture plate and released (Gel-R). A) Contraction of engineered lamina propria as a function of culture time. B) Normalized MTT cell viability assay at day 7. DAPI stained cryosections of engineered lamina propria after 7 days of culture on C) decellularized dermis, D) electrospun collagen, E) collagen gel, and F) collagen gels that were released. White line indicates the bottom of each substrate. G) Quantification of the depth of penetration into each scaffold.
Fig 3.
Comparison of cytokeratin and basement membrane protein expression between normal and engineered human engineered gingiva.
Immunostained sections of normal human and engineered human gingiva at culture days 10 and 14. Scale bar = 50 μm for engineered gingiva and 100 μm for all native human gingiva to capture the entire epidermis.
Fig 4.
Comparison of stromal constituents in normal and engineered human gingiva.
at Both normal and engineered gingiva showed dense fibroblast layers (positive staining for TE-7); however, gingival fibroblasts populated the upper half of the connective tissue scaffold in the engineered tissue whereas they were present throughout the stromal component in normal gingiva. Dense, mature collagen type I bundles (red staining) are observed in a cross-hatched pattern in normal human gingiva while new collagen has just begun to be deposited in the upper stromal region at day 14 in the engineered gingiva. Scale bar = 100 μm for TE-7 stain and 50 μm for picrosirius red staining.
Fig 5.
In vitro attachment of human engineered gingiva to abutment materials.
H&E-stained ground sections of different abutment materials “implanted” into the engineered gingiva after 7days in culture. A) Machined commercially pure Ti, B) SLA surface modified Ti, C) TiN, D) Zirconia and E) PEEK implants exhibit a wide range of engineered gingival adhesion to the engineered gingiva. Machined Ti and PEEK have significant engineered tissue attachment to the abutment while the zirconia and TiN show weak attachment. No engineered gingiva attachment was observed with the TiN materials. Scale bar = 100 μm.
Fig 6.
Residual tissue attachment to abutment materials after removal from human engineered gingiva.
Scanning electron micrographs of abutment posts following implantation into human engineered gingiva for 7 days. A) Machined CP Ti, B) SLA surface modification, C) TiN, D) Zirconia and E) PEEK implants. Residual cellular attachment to the abutment surface following abutment retrieval was observed in the machined CP Ti, zirconia and PEEK groups. Scale bar = 300 μm.