Periodontal ligament (PDL) with structural connectivity between cementum and alveolar bone tissues has key functions to optimize positional stabilities of teeth, transmit and absorb various stresses under masticatory/occlusal loading conditions, or promote tissue remodeling by mechanical stimulations. The oriented PDL formations with micron-scaled dimensions and calcified interfacial tissue formation with fibrous tissue anchorages are challenging in bone-ligament complex neogeneses. We investigated the 3-D microarchitectures, which can spatiotemporally organize PDL for fibrous connetive tissue formations.
The periodontal regeneration scaffolds had three compartmentalized microarchitectures; cementogenesis platform (~200um), PDL-guiding architectures, and bone scaffolds. After computer designs, 3-D printing system manufactured micron-scaled wax molds and biodegradable material (poly-ε-caprolactone; PCL) was casted into wax molds. The architectures were characterized with micro-CT, SEM, and confocal microscope for topographies. In in-vitro human PDL cell cultures and in-vivo subcutaneous model system, cell orientations or angulations were analyzed with nuclear morphologies and deformations.
In in-vitro experiments, microgrooves on scaffold architectures can angularly organize and geometrically control cell orientations for 7-day and 21-day cultivations. In particular, micro-patterns on microarchitectures can predictably and accurately control PDL cell orientations with high proliferations. Moreover, microgroove-patterned scaffolds promisingly provided more predictable cell alignments and cell orientations were significantly angular-controllable with statistical difference in in-vivo.
The additive manufacturing system can fundamentally manufacture various microarchitectures with micron-scaled patterns, which are designed in CAD. Based on topographical cues, PDL stem cells can be spatiotemporally regulated for fibrous connective tissue and mineralized tissue formations as well as scaffolds can control specific orientations of ligament cells and tissues. Therefore, the investigation demonstrates the compartmentalized microarchitectures facilitate to regenerate periodontal complexes which have structural similarities to natural periodontia.