## 1 Introduction  
Periodontia or periodontal tissues have typically spatial compartmentalization for different tissue types, like cementum (the mineralized layer on tooth-root surface), periodontal ligament (PDL; fibrous connective tissues with perpendicular orientations to tooth-root surface), alveolar bone (the mineralized structures to support tooth constructs), and gingiva (the soft tissue structure to protect tooth-surrounding tissues as a barrier) [1]. In particular, the tooth-supporting (or periodontal) complex is the hierarchical architecture, like cementum-PDL-bone with strong tissue integrations by Sharpey's fibers, which are the terminal ends of principal fibers to facilitate PDL bundle insertions into the mineralized tissue surfaces like cementum and bone surface [2; 3; 4]. Of various tooth-supportive functions in the periodontal complex, PDL requires spatiotemporal orientations and angular configurations to mainly generate biomechanical responses under mastication loadings [2; 5]. Periodontitis or periodontal disease is the inflammatory chronic disease to induce the destructions of tooth-supporting structures and increase serious tooth mobility, including tooth root exposures, which can produce sensory responses or pains from the dental pulp [6; 7; 8]. Some severe cases require tooth extractions and place dental prosthetics, like dental implants or dentures to replace functioning of natural teeth. However, dental implants, which are directly placed into regenerated bone tissues or bone substitutes after bone healing within the tooth-extraction socket have recently reported about peri-implantitis, lost stability of implants, sensory limitations, or biomechanical malfunctioning [9; 10; 11]. Therefore, periodontal tissue constructs and their systemic integrations are significantly required to support and preserve natural teeth [3; 4; 12]. Various spatiotemporal scaffolding systems have been recently developed and applied for tissue replacement or regeneration. Many different types of scaffolding systems have been developed for multi-tissue and interface formations [4; 9; 13; 14; 15], but, to date, these approaches still have limitations in complete tissue integration, their functional restorations, and regenerated tissue-controllable architecture designs. After culturing PDL cells on thermosensitive culture dishes, engineered PDL cell sheets facilitated to promote periodontal tissue regeneration like cement, PDL, and alveolar bone around the periodontal defects in the canine model [16]. The strategy could be beneficial without artificial biomaterials in transplanting biologics, but it was limited to 3D organize fibrous connective tissues with specific angulations, which would be the main factor in restoring periodontal functions and generating appropriate biomechanical responses against mastication loadings [16; 17]. To overcome the difficulties, computer design-based fabrication techniques, such as rapid prototyping and solid freeform fabrication methods, can permit the design of desired and predictable geometric structures to regulate multiple tissue formations [5; 13]. Up to recently, [PERSON] et al. investigated fiber-guiding biopolymeric scaffolds for alveolar bone and PDL (bone-PDL scaffold) regenerations while using the additive manufacturing system in mandibular fenestration defects of the rodent model [15; 18]. In addition, the selective laser sintering (SLS) system created the designed biopolymeric scaffold with the remarkable architectural adaptability to the disease-induced geometric defect [14]. In addition, soft lithographic strategies are currently utilized to investigate optimal designs with sub-micron level topographic architecture for the perpendicular PDL guidance [19; 20]. The freeze-casting method could create 3D longitudinal pore structures as the PDL-guidable architectures and control the pore directionalities for the structural similarity to natural PDL orientations [5].