Functional Hydrogels and Their Applications in Craniomaxillofacial Bone Regeneration

Abstract

Craniomaxillofacial bone defects are characterized by an irregular shape, bacterial and inflammatory environment, aesthetic requirements, and the need for the functional recovery of oral–maxillofacial areas. Conventional clinical treatments are currently unable to achieve high-quality craniomaxillofacial bone regeneration. Hydrogels are a class of multifunctional platforms made of polymers cross-linked with high water content, good biocompatibility, and adjustable physicochemical properties for the intelligent delivery of goods. These characteristics make hydrogel systems a bright prospect for clinical applications in craniomaxillofacial bone. In this review, we briefly demonstrate the properties of hydrogel systems that can come into effect in the field of bone regeneration. In addition, we summarize the hydrogel systems that have been developed for craniomaxillofacial bone regeneration in recent years. Finally, we also discuss the prospects in the field of craniomaxillofacial bone tissue engineering; these discussions can serve as an inspiration for future hydrogel design.

Hydrogels in Dental Medicine

“…In addition, hydrogels with tunable mechanical properties can fulfill the needs of loadbearing defects. [21,292] It is recommended that the mechanical properties of craniofacial scaffolds should either match those of native tissue or, at a minimum, meet a certain threshold value. [293] However, there is limited experimental evidence to establish the required percentage of native tissue mechanical properties for a scaffold.…”

“…[293] The adjustable stiffness of hydrogels has been reported to reach 0.5 kPa-5 MPa, which can be altered by varying the cross-linking within the hydrogels, incorporating nanoparticles, and combining different polymers to create hybrid hydrogels. [21] For example, in carbon dots/nano-HA/PVA hydrogels, adding 0.6% solid content of nano-hydroxyapatite optimized the compression strength to 3.462 MPa. [297] Hydrogel scaffolds are used to incorporate growth factors (e.g., BMP, TGF, and VEGF) and stem cells (e.g., BMSCs, DSCs, and ADSCs) to facilitate the proliferation and differentiation of osteoblasts and osteocytes.…”

“…In addition, hydrogels with tunable mechanical properties can fulfill the needs of load‐bearing defects. [ 21,292 ]…”

“…[ 293 ] The adjustable stiffness of hydrogels has been reported to reach 0.5 kPa–5 MPa, which can be altered by varying the cross‐linking within the hydrogels, incorporating nanoparticles, and combining different polymers to create hybrid hydrogels. [ 21 ] For example, in carbon dots/nano‐HA/PVA hydrogels, adding 0.6% solid content of nano‐hydroxyapatite optimized the compression strength to 3.462 MPa. [ 297 ]…”

“…[8,9] Since their initial use in biological applications by Whichterler and Lim in 1960, [10] hydrogels have been widely used in various biomedical applications, including in drug delivery; [11] as tissue engineering scaffolds; [12] for encapsulation of cells, proteins, and other biomolecules; [13] as biosensors in wearable devices or responsive units; and as intrinsic antimicrobial materials. [14] In recent years, hydrogels have emerged as promising biomaterials in dental medicine (Figure 1), for encapsulating antibacterial agents to combat bacteria in periodontitis, [15,16] caries, [17] and pulp diseases, [18] as scaffold materials to regenerate dental tissues [19][20][21] and as drug delivery systems to regulate orthodontic tooth movement (OTM). [22] In this review, we highlight the various applications of hydrogels in dental medicine, including their therapeutic effects, limitations, and future potential.…”