. 2021 Apr 20;12:20417314211003735. doi: 10.1177/20417314211003735

Table 1.

Summary of the tissue engineering approaches in the craniofacial region.

Authors	Study type	Year	Regenerative construct	Study model	Reported results	References
Bone regeneration
Maliha et al.	In vivo	2020	Dipyridamole coated 3D printed B-tricalcium phosphate with varying pore dimensions (220, 330, and 500 µm)	Calvarial defects in rabbits	Large pore scaffolds with Dipyridamole coating showed most bone growth	¹⁸
Francis et al.	Clinical retrospective trial	2012	Endoscopic craniofacial reconstruction with injectable calcium phosphate cement	Secondary craniofacial reconstruction	The study group showed efficacious, cost-effective reconstruction	³¹
Kirschner et al.	In vivo	2020	Carbonated calcium phosphate cement in craniectomy defects	Frontal cranial defects in immature piglets	The study group with the CRS showed promising bone healing without growth hinderance when compared to the negative control	³²
Mediero et al.	In vivo	2016	Collagen sponge with CAM/ticagrelor 1 µm/10 µm	Calvarial defect in mice	Ticagrelor and CAM both showed more bone formation three dimensionally as compared to negative control (scaffold with saline). Comparable to the amount of bone when BMP was used	³⁵
Mediero et al.	In vivo	2016	3D printed collagen coated hydroxyapatite—βtricalcium phosphate scaffolds with ticagrelor 1 mM or CAM 1 mM	Calvarial defect in mice	Both ticagrelor and CAM showed significantly more bone formation than scaffold alone and comparable amount to the BMP treated defect	³⁵
Nokhbatolfoghahaei et al.	In vitro	2020	Gelatin/β-tricalcium phosphate scaffolds loaded with mesenchymal cells from the buccal fat pad and rotating-perfusion versus perfusion bioreactors	–	Rotating-perfusion bioreactor group showed higher RUNX2, OCN expressions and ALP and collagen one production increase when compared to the static and perfusion bioreactor	³⁶
Lopez et al.	In vivo	2019	3D-printed bioceramic scaffolds with 1000 μm of dipyridamole/10,000 μm of dipyridamole/0.2 mg/ml of rhBMP-2	Alveolar clefts in white immature rabbits	Dipyridamole allowed bone healing comparable to the BMP group with the early suture closure seen with the latter. The formed bone in both groups were of mechanical properties comparable to that of the native bone	³⁷
Wang et al.	In vivo	2019	Dipyridamole loaded 3D printed β-tricalcium phosphate scaffolds	Calvarial and alveolar defects in immature rabbits	The scaffolds showed significant bone formation in comparison to the gold standard bone graft	³⁸
Zhao et al.	In vitro	2009	β-tricalcium phosphate mixed with fibrinogen and thrombin to make injectable scaffolds	–	Human mesenchymal stem cells showed cytoviability and cellular number increase in the scaffold. Increased β-TCP content enabled a higher elastic modulus of the final scaffold	⁴¹
Wang et al.	In vitro	2016	Injectable calcium phosphate cement scaffolds with different cell types hDPSCs, hiPSC-MSCs from bone marrow (BM-hiPSC-MSCs) and from foreskin (FS-hiPSC-MSCs) and hBMSCs	–	The scaffolds supported cell viability, osteogenic differentiation. All cell types showed expression of bone forming genes. FS-hiPSC-MSCs were reported to be relatively inferior to the rest of the cell types in osteogenesis	⁴²
Hasani-Sadrabadi et al.	In vivo	2020	Injectable alginate-based hydrogel scaffold (AdhHG) with mesenchymal stem cells	Subcutaneous implantation in mice	The hydrogel was proven to be biocompatibility, biodegradable and osteoconductive	⁴³
Hasani-Sadrabadi et al.	In vivo	2020	Injectable Alginate-based hydrogel scaffold (AdhHG) with gingival mesenchymal stem cells	Rat peri-implantitis models	Complete bone regeneration was achieved around failing dental implants	⁴³
Chen et al.	In vivo	2019	DBBM/collagen gel/DBBM + collagen gel	Rabbit calvarial model	Addition of DBBM significantly improved immature bone formation while the Gel group improved soft tissue healing. The combination treatment is the best way to manage multi-tissue regeneration	⁴⁷
Salamanca et al.	In vivo	2016	Freeze-dried porcine collagen membrane with bovine xenograft	Lateral alveolar ridge defects in beagle dogs	The new collagen membrane improves osteoconduction and reduces alveolar height resorption rate	⁴⁸
Salamanca et al.	In vitro	2020	Collagenated porcine graft compared to porcine graft, HA/β-tricalcium phosphate with MG-63 osteoblast-like cell line	–	CPG group showed greater cell proliferation and osteoblastic differentiation. Gene sequencing showed stable bone formation markers and reduction of resorption makers	⁴⁹
Salamanca et al.	In vivo	2020	Collagenated porcine graft compared to porcine graft, HA/β-tricalcium phosphate	Calvarial defects in adult male white rabbits	CPG group showed the highest new bone regeneration by osteoconduction	⁴⁹
Cassetta et al.	Clinical trial	2015	Augmentation using 100% autologous bone, 100% porcine graft, 50:50 mixture of both	Sinus augmentation	Porcine bone alone and with autologous bone showed osteoconductivty and biocompatibility	⁵⁰
Ning et al.	In vivo	2019	LAGG-PM composite hydrogels with rat adipose-derived stem cells (rADSCs)	MRONJ induced rat model	LAGG-PM composite hydrogels were found to promote mucosal recovery, bone tissue reconstruction, and osteoclastogenesis	⁵²
Rodrigues-Lozano et al.	In vivo	2020	Bone marrow derived-MSCs cultured on β-Tri calcium phosphate	MRONJ induced mouse model (maxillary alveolar sockets)	No MRONJ-related bone exposure was detected in the study group versus 33% exposure in the control (β-TCP and saline)	⁵³
Sallstrom et al.	In vitro	2020	Zwitterionic sulfobetaine hydrogel with direct culture of neuroblastoma cell line VS indirect culture		The material seemed to support cellular growth and proliferation and that was supported by the appearance of extended neurites on the hydrogel surface	⁵⁴
Diez-Escudero et al.	In vitro	2020	Porous polylactic acid scaffolds with Diamon/Gyroid/Schwarz internal configuration with pre-osteoblastic cell lines		No cytotoxicity was reported. The larger and multimodal porosity supported differentiation better	⁵⁵
Muscle regeneration
Manchineella et al.	In vitro	2016	Silk fibroin/melanin films and electrospun fiber sheets as scaffolds with C2C12 myoblast cell line	–	The scaffolds promoted the myoblast’s assembly and differentiation and proved thermal stability provided by melanin	⁶¹
Vandenburgh et al.	In vitro	2008	Primary mouse myoblasts on polydimethylsiloxane (PDMS) attached to flexible microposts of varying diameters (300–800 µm), 4–5 mm tall, and 4 mm apart	–	The miniature bioartificial muscles generated active forces upon electric stimulation	⁶²
Abou Neel et al.	In vitro	2005	Phosphate-based glass fibers (PGF) with different iron oxide (Fe₂O₃) molarity	–	PGF with larger diameters and 3–5 mol% Fe₂O₃ are more durable scaffolds that should allow for better initial myoblast attachment than others with 1 or 2 mol% Fe₂O₃	⁶³
Farano et al.	In vitro	2018	Melt-quenched phosphate glasses were combined as powders with collagen fibers from bovine achilles tendon to make degradable scaffolds	Scaffold characterization	Characterization of the fabricated scaffolds showed interconnected porous structures and biodegradability. Bioactivity was proven by finding a Ca-P rich layer on all scaffolds’ surfaces—whish was comparable to that formed by HA in one sample	⁶⁴
Guo et al.	In vitro	2019	Injectable electroactive degradable hydrogels (dextran-graft-tetraaniline and N-carboxyethyl chitosan) with C2C12 myoblasts and human umbilical vein endothelial cells		Biocompatibility was confirmed Myoblasts showed linear like release	⁶⁵
Guo et al.	In vivo	2019	Injectable electroactive degradable hydrogels (dextran-graft-tetraaniline and N-carboxyethyl chitosan) with C2C12 myoblasts and human umbilical vein endothelial cells	200 µL were injected subcutaneously in rat tibialis anterior defects	Due to it’s injectability, the hydrogel allows non-surgical implantation high myofiber density, more capillaries, and centronucleated myofibers in the defect were detected in all study groups with significantly higher numbers of centronucleated myofibers in the 3% AT scaffolds	⁶⁵
Jung et al.	In vivo	2017	Pulp cells extracted from adult human premolars treated with 5-Aza	Gastrocnemius and masseter muscles of male mice	The epigenetic modification with 5-Aza stimulated muscle regeneration in vivo	⁷⁰
Brady et al.	In vitro	2008	Human myogenic and non-myogenic muscle-derived cells (MDC) seeded in 3D collagen constructs		Non-myogenic cells can be used for 3D myogenic differentiation, force generation and matrix remodelling	⁷¹
Brady et al.	In vitro	2008			The mix of cell origins had a synergistic effect on peak force and MMP-2 mRNA expression	⁷¹
Shah et al.	In vitro	2004	Human masseter derived cells cultured on phosphate-based glass fibers of different orientations		3D mesh arrangement of the glass fibers supported the best cell attachment and proliferation	⁷²
Shah et al.	In vitro	2004			Increasing seeding density and adding ILGF-1 and Matrigel enhanced prototypic muscle fiber formation	⁷²
Zhang et al.	In vivo	2019	Human amniotic mesenchymal cells with the DNA demethylating agent 5-azacytidine	Volumetric muscle loss in rat tibialis anterior muscle	The rat model showed improved local tissue repair and increased angiogenesis	⁷⁴
Cartilage regeneration
Vinatier et al.	In vivo	2009	Autologous rabbit nasal chondrocytes (RNC) associated with an injectable self-setting cellulose-based hydrogel (Si-HPMC)	Rabbit articular cartilage defect	The defect treated with RNC showed formation of repair tissue organized similar to normal cartilage	⁷⁷
Vinatier et al.	In vivo	2009		Rabbit articular cartilage defect	The regenerated tissue was histologically hyaline-like cartilage	⁷⁷
Ahtiainen et al.	In vivo	2013	Bi-layer polylactide (PLA) discs and autologous adipose stem cells (ASCs) with TGF-β1 for TMJ disc regeneration	Rabbit temporomandibular joints	ASC—PLA discs pre-treated with TGF-β1 improved condylar integrity	⁷⁸
Ahtiainen et al.	In vivo	2013		Rabbit temporomandibular joints	Histologically, no inflammation, infection or foreign body reactions were detected	⁷⁸
Vapniarsky et al.	In vivo	2018	Scaffold-free tissue constructs from passaged costal chondrocytes	Intralaminar implantation in TMJ discs of minipigs	The tissue engineered construct group showed better healing of the defect than the empty control. Histologically the cartilaginous formation and collagen content change was noted, while the mechanical properties of the constructs were also acceptable. Necropsy revealed no signs of cell damage/inflammation/neoplastic changes	⁷⁹
Cakmak et al.	In vivo	2013	Injectable tissue engineered cartilage within a fibrin glue with/without aprotinin, different concentrations of thrombin and fibrinogen. (chondrocytes harvested from auricle/costa/nasal septum)	Subcutaneous injection interocular and forehead of white rabbits	Inflammatory reactions, abscess formation, and foreign body reactions around the new cartilage tissue of tissue-engineered cartilage	⁸⁰
Cakmak et al.	In vivo	2013			The different groups (concentrations of constituents/cell sources) showed no statistically significant differences	⁸⁰
Kim et al.	In vivo	2019	Human umbilical cord matrix-mesenchymal stem cells (hUCM-MSCs) for the treatment of TMJ-osteoarthritis in comparison to other MSCs origins	Intra-articular injection in rabbit models with induced TMJ osteoarthritis	Regenerative and anti-inflammatory capacity of the hUCM-MSCs was clear	⁸²
					hUCM-MScs anti-inflammatory effect was comparable to that of dexamethasone
					Moreover, only hUCM-MSCs showed potential for chondrogenesis.
Cui et al.	In vivo	2020	Human dental pulp stem cells (DPSCs) were injected into the articular cavity to treat rat TMJ arthritis	Local injection in arthritic temporomandibular joints of female rats	Local injection of DPSCs in rats with arthritic joints of rats relieved hyperalgesia, synovial inflammation, reduced cartilage degradation, and enhanced bone regeneration	⁸³
Ogasawara et al.	In vivo	2020	IV injection of conditioned media from human exfoliated deciduous teeth stem cells (SHED-CM)	Injection in induced osteoarthritic mouse model	Suppressed temporal muscle inflammation, and improved bone integrity and surface smoothness of the destroyed condylar cartilage	⁸⁴
Zhang et al.	In vivo	2019	Mesenchymal stem cells’ exosomes injection	Intra-articular injection in 8-week old rats’ osteoarthritic TMJ	MSC exosomes promoted TMJ repair and regeneration in OA The cell-free ready-to-use exosome-based therapeutic potential for treating TMJ pain and degeneration is significant	⁸⁵
Kuznetsov et al.	In vivo	2019	Undifferentiated bone marrow stromal cells (BMSCs) on fibrin microbeads (FMBs)	Subcutaneous injection in immunocompromised mice	Significant amounts of hyaline-like cartilage were reported when BMSCs were attached to hyaluronic acid coated FMBs	⁸⁶
Chen et al.	In vivo	2020	3D fabricated decellularized bone scaffolds with autologous adipose-derived chondrogenic and osteogenic cells.	Ramus-condyle defect models in minipigs	The fabricated RCUs maintained their structure and cartilage was regenerated over the underlying bone more than the bone only and acellular scaffold comparators	⁸⁷
Park et al.	In vivo	2017	3D-printed PolyCaproLactone implants	Septal grafting for nasal reshaping in white rabbits	The implants retained their location	⁸⁹
Park et al.	In vivo	2017	3D-printed PolyCaproLactone implants	Septal grafting for nasal reshaping in white rabbits	Histologically, the implant retained its morphology with significant fibrovascular ingrowth and minimal inflammation	⁸⁹
Reuther et al.	In vitro	2014	Human septal chondrocytes expanded and resuspended in alginate on transwell clear polyester membrane insert		The expanded constructs were histologically similar to those of the standard size	⁹⁰
Mendelson et al.	In vivo	2014	Alginate containing gelatin microspheres encapsulating cytokines on PLGA base (with r-TGFβ3 at different concentrations)	Rhinoplasty model in rats	Cartilage-like tissue formation was enhanced by increasing doses of TGFβ3	⁹¹
Mendelson et al.	In vivo	2014		Rhinoplasty model in rats	This technique may be a successful alternative for augmentative and reconstructive rhinoplasty	⁹¹
Yi et al.	In vivo	2019	3D model of customized nasal implant with injected hydrogel containing human adipose-derived stem cells	Subcutaneous implantation in mice	Maintenance of the exquisite shape and structure, and striking formation of the cartilaginous tissues for 12 weeks	⁹²
Cao et al.	In vivo	1996	PGA-PLA scaffolds with chondrocytes isolated from bovine articular cartilage	Subcutaneous pockets on dorsa of athymic mice	Morphologic and histologic assessment showed the formation of new cartilage	⁹⁴
Cao et al.	In vivo	1996		Subcutaneous pockets on dorsa of athymic mice	The overall geometry resembled that of an infant auricle	⁹⁴
Morrison et al.	In vivo	2016	Human auricular chondrocytes (hAuC) and human mesenchymal stem cells (hMSC) encapsulated into type I collagen hydrogels shaped like full scale-ear constructs	Subcutaneously implanted in mice dorsa	The construct showed cartilage microstructure	⁹⁵
Morrison et al.	In vivo	2016		Subcutaneously implanted in mice dorsa	The human ear constructs maintained shape, projection, and flexibility	⁹⁵
Kagimoto et al.	In vivo	2016	Xenotransplantation of progenitor cells to reconstruct ear cartilage.	Subcutaneous region of a craniofacial defect in a monkey	Elastic cartilage was regenerated	⁹⁶
Kagimoto et al.	In vivo	2016		Subcutaneous region of a craniofacial defect in a monkey	Mature elastic cartilage with newly formed perichondrium was successfully detected	⁹⁶
Liao et al.	In vivo	2015	A chondrocyte membrane on an ear-shaped Ti model	Implanted in dorsal pockets of nude mice	Histologically the newly formed tissue was confirmed to be elastic cartilage	⁹⁷
Matuska et al.	In vitro	2018	Effect of delipidation on decellularized porcine TMJ disc with seeded human MSCc		A combination of solvents and surfactant treatment no cytotoxicity or residual lipid content was noted	⁹⁸
Nerve regeneration
Binnetoglu et al.	In vivo	2019	Bacterial cellulose conduits for nerve regeneration with or without primary suturing	Main trunk of facial nerve in female rats	The number of myelinated fibres was significantly higher with the placement of bacterial cellulose conduits	¹⁰⁷
Piao et al.	In vivo	2020	Collagen conduits with collagen-binding domain (CBD)-human basic fibroblast growth factor (bFGF)	Buccal branch of facial nerve injury model in white rabbits	CBD-bFGF enhanced functional facial nerve regeneration	¹⁰⁸
Watanabe et al.	In vivo	2017	Silicone conduits with differentiated and undifferentiated Adipose derived stem cells (ADSCs) embedded in a collagen gel	Nerve defect in the buccal branch of the facial nerve of rats	Functional nerve regeneration was evident in all groups comparable to results of autologous nerve grafts	¹¹⁰
Sasaki et al.	In vivo	2011	Degradable PLGA tubes filled with dental pulp cells (DPCs) embedded in collagen gel	Nerve defects in the buccal branch of mandibular nerve of adult rats	The PLGA tubes resorbed in vivo Tuj-1 positive axons were noted 2 months after transplantation	¹¹¹
Costa et al.	In vivo	2013	Bone marrow stem cells in Polyglycolic acid tube conduits with BMSCs/Schwann-like cells differentiated from BMSCs	Mandibular branch of facial nerve defects in rats	Facial nerve regeneration was improved by PGAt and the Schwann-like cells enhanced the regeneration potential	¹¹²
Xiao et al.	In vitro	2017	Dental pulp cell spheroids on matrigel in vitro		DPCs differentiated into neuronal lineage under neuronal inductive conditions	¹¹³
Xiao et al.	In vitro	2017	Dental pulp cell spheroids on matrigel in vitro		They can stimulate neurogenesis in mouse hippocampal slices in vitro	¹¹³
Salivary gland regeneration
Joraku et al.	In vivo	2005	Primary human salivary gland cells grown expanded and seeded on Polyglycolic acid scaffolds	Subcutaneous implantation in mice	Histologically acinar gland-like structures were noted in the regenerated tissue	¹²¹
Joraku et al.	In vivo	2005		Subcutaneous implantation in mice	Expression of human salivary type of α-amylase mRNA was confirmed	¹²¹
Joraku et al.	In vitro	2007	Human salivary cells cultured, expanded and seeded on a 3D collagen-based gel scaffold	–	Functional, differentiated salivary units containing acini and ducts were reported	¹²²
Nam et al.	In vivo	2019	Submandibular gland cell sheets (single vs multiple layers)	Direct placement into the wounded submandibular glands of mice	Single layer cells retained the cell-to-cell junctions. The double layer sheets formed glandular like structures in vitro.	¹²⁵
Ogawa et al.	In vivo	2013	Bioengineered gland germ from cells from submandibular, sublingual and parotid glands of mice with PGA extension into the parotid duct	Implanted atop the masstere muscle after extraction of salivary glands in female mice	Salivary flow and content was comparable of that in normal mice	¹²⁴
Nam et al.	In vivo	2017	Submandibular gland cells on Fibrin Hydrogels with L1 peptide conjugation	Submandibular gland wound models in mice	Organized salivary tissue was formed with good collagen organization was noted in the group with the FH scaffolds	¹²⁶
Maruyama et al.	In vitro	2015	Combination of laminin and a feeder layer of human hair follicle derived mesenchymal stem cells (hHF-MSCs)	–	hHF-MSC conditioned medium improved cellular orientation and allowed acinar and ductal structure formation	¹²⁷
Su et al.	In vivo	2020	Labial stem cells from human labial glands were extracted and expanded, the extract (LSCE) after centrifugation was used to regenerate irradiated salivary glands	Irradiated mice were injected with the LSCE through the tail vein	50%–60% increase in salivary flow was noted in LSCE treated mice in comparison to the control group	¹²⁹
Su et al.	In vivo	2020			Histologically a comparable number of acinar and neurovascular components was noted	¹²⁹
Skin, mucosa, and periodontal regeneration
Gielkins et al.	In vivo	2008	Poly (DL-lactide-e-caprolactone) (PDLLCL) membrane versus collagen and expanded polytetrafluoroethylene (ePTFE) membranes in implant defects	Mandibular angle defects in male rats	PDLLCL membranes showed less bone formation than the collagen and ePTFE membranes	¹³²
Duskova et al.	In vivo	2006	Resorbable collagen membranes (single-layer and double-layer); porcine collagen type I and III membrane versus atelocollagen membrane	Clinical alveolar defects with cancellous bone grafts	No statistically significant difference was found between the groups although the double membrane was more expensive	¹³⁴
Cortellini et al.	Clinical in vivo	2011	Non-resorbable/bio-resorbable barrier membranes; enamel matrix derivative (EMD)/a combination of bio-resorbable membranes and a bovine xenograft of bovine origin/a combination of EMD and alloplastic biomaterials/a combination of bio-resorbable membranes and EMD versus extraction and restoration of hopeless teeth	Hopeless teeth with perio-endo lesions	92% of the teeth treated with regeneration protocols lasted throughout the 5-year follow-up	¹³⁵
Cortellini et al.	Clinical in vivo	2011		Hopeless teeth with perio-endo lesions	Most of the regenerated teeth showed reduction in mobility	¹³⁵
Liu et al.	In vitro	2020	Assessment of potential use of Human periodontal ligament stem cells (hPDLSCs) to differentiate into different cell lineage	–	hPDLSCs were able to differentiate into bone-, fiber- and cementum-forming cells, and so can be used for regeneration of periodontium—bone-PDL-cementum complex specifically	¹³⁶
Guo et al.	In vivo	2017	Dental follicle cell (DFC) sheets and periodontal ligament cell (PDLC) sheets in periodontal defects	Healthy beagle dogs with simulated periodontal defects	Periodontal attachment was noted in both groups. Periodontal ligament–cementum complex structure and better alveolar bone height was only noted in the DFC sheet group	¹³⁷
Guo et al.	In vivo	2017		Healthy beagle dogs with simulated periodontal defects	DFC sheets are more effective for periodontal regeneration	¹³⁷
Xue et al.	Clinical trial	2018	Human acellular amniotic membrane (HAAM) with Vaseline gauze	Full-thickness defects in the lower third of the nose in humans	HAAM improved hemostasis and accelerated pain reduction. Lower infection rates and scar incidence were also noted	¹⁴⁰
Chen et al.	Clinical trial	2018	Bioengineered dermal substitute (dermal regeneration template)	Human traumatic periocular tissue loss	Defects either healed completely (50%), one case showed significant improvement not requiring secondary reconstructive procedures, and one other case showed significant reduction in defect size	¹⁴²
Rhee et al.	Clinical trial	1998	Acellular dermal matrix in comparison to split thickness skin grafting	Intraoral mucosal defects in humans	Graft take was successful in 90% of the cases	¹⁴³
Seol et al.	In vivo	2018	BioMask—a customized bioengineered skin substitute which fits perfectly onto facial wounds	Face defects in mice	Skin regeneration was noted at the dermis and epidermis levels	¹⁴⁴
Seol et al.	In vivo	2018		Face defects in mice	According to patient’s CT; wound dressing material and cell-laden hydrogels are accurately printed in a layer-by-layer way	¹⁴⁴
John et al.	In vitro	2019	De-epithelialization of human amniotic membrane as a cellular scaffold as a skin substitute	–	Trypsin and cell scraper provided best de-epithelialization results but showed tissue strain	¹⁴⁵
John et al.	In vitro	2019		–	Culturing of keratinocytes and fibroblasts on the membrane was successful and resulted in a mostly keratinized surface	¹⁴⁵
Roh et al.	In vivo	2017	Mucosa and skin equivalents were produced from cultured fibroblasts and autologous fibrin and seeding keratinocytes	Full-thickness excisional wounds of rat skin	The cell sheets enhanced healing with earlier wound closure and less scarring	¹⁴⁷
Roh et al.	In vivo	2017		Full-thickness excisional wounds of rat skin	Lower TGF-β1, α-smooth muscle actin, and fibronectin mRNA expression was also noted	¹⁴⁷
Suzuki et al.	In vitro	2020	Fish scale type I collagen scaffolds as oral mucosa equivalent	–	Histologically, a fully differentiated epithelial layer was noted indicating that the microstructured fish scale collagen scaffolds can be used to fabricate tissue-engineered oral mucosa equivalents for clinical use	¹⁵⁰
Engineering of multiple tissues
Costa et al.	In vivo	2014	Biphasic scaffold with a bone compartment (coated with a calcium phosphate (CaP) layer) and a periodontal PCL compartment	Subcutaneous implantation dorsally in nude male rats	The CaP compartment showed significant ALP activity while the PCL compartment showed with the larger pores allowed better vascularization and periodontal attachment	¹⁵³
Lee et al.	In vivo	2014	PCL-HA scaffolds with three phases (100 mm microchannels for cementum/dentin interface, 600 mm microchannels for PDL, and 300 mm microchannels for alveolar bone) with DPSCs, PDLSCs, and ABSCs	Subcutaneous pouches in immunodeficient mice	Properly oriented PDL-like collagen fibers, bone sialoprotein-positive bone-like tissue and putative cementum matrix/dentin tissues were found indicating success of the multiphasic scaffold	¹⁵⁴