Composite Graded Melt Electrowritten Scaffolds for Regeneration of the Periodontal Ligament-to-Bone Interface

Integration of Melt Electrowritten Polymeric Scaffolds and Bioprinting for Epithelial Healing via Localized Periostin Delivery

Management of skin injuries imposes a substantial financial burden on patients and hospitals, leading to diminished quality of life. Periostin (rhOSF), an extracellular matrix component, regulates cell function, including a proliferative healing phase, representing a key protein to promote wound healing. Despite its proven efficacy in vitro, there is a lack of scaffolds that facilitate the in situ delivery of rhOSF. In addition, there is a need for a scaffold to not only support cell growth, but also to resist the mechanical forces involved in wound healing. In this work, we synthesized rhOSF-loaded mesoporous nanoparticles (MSNs) and incorporated them into a cell-laden gelatin methacryloyl (GelMA) ink that was bioprinted into melt electrowritten poly(ε-caprolactone) (PCL) microfibrous (MF-PCL) meshes to develop mechanically competent constructs. Diffraction light scattering (DLS) analysis showed a narrow nanoparticle size distribution with an average size of 82.7 ± 13.2 nm. The rhOSF-loaded hydrogels showed a steady and controlled release of rhOSF over 16 days at a daily dose of ∼40 ng/mL. Compared with blank MSNs, the incorporation of rhOSF markedly augmented cell proliferation, underscoring its contribution to cellular performance. Our findings suggest a promising approach to address challenges such as prolonged healing, offering a potential solution for developing robust, biocompatible, and cell-laden grafts for burn wound healing applications.

Materials and Strategies to Enhance Melt Electrowriting Potential

Melt electrowriting (MEW) is an emerging additive manufacturing (AM) technology that enables the precise deposition of continuous polymeric microfibers, allowing for the creation of high-resolution constructs. In recent years, MEW has undergone a revolution, with the introduction of active properties or additional functionalities through novel polymer processing strategies, the incorporation of functional fillers, postprocessing, or the combination with other techniques. While extensively explored in biomedical applications, MEW's potential in other fields remains untapped. Thus, this review explores MEW's characteristics from a materials science perspective, emphasizing the diverse range of materials and composites processed by this technique and their current and potential applications. Additionally, the prospects offered by postprinting processing techniques are explored, together with the synergy achieved by combining melt electrowriting with other manufacturing methods. By highlighting the untapped potentials of MEW, this review aims to inspire research groups across various fields to leverage this technology for innovative endeavors.

Melt electrowriting scaffolds with fibre-guiding features for periodontal attachment

Periodontal regeneration requires the re-attachment of oblique and perpendicular periodontal ligament (PDL) fibres to newly formed cementum and alveolar bone, which has proven elusive with existing approaches. In this study, multiple fibre-guiding biphasic tissue engineered constructs were fabricated by melt electrowriting. The biphasic scaffolds were 95 % porous and consisted of a pore size gradient bone compartment and periodontal compartment made of fibre-guiding channels with micro-architectural features ranging from 100 to 60 µm aimed to direct PDL fibre alignment and attachment. In vitro evaluations over 3 and 7 days demonstrated a marked improvement in collagen fibre orientation (over 60 % fully aligned) for scaffolds with micro-architecture ≤100 µm. The biphasic scaffolds were placed on a dentine slice and implanted ectopically, and this demonstrated that all micro-channels groups facilitated oblique and perpendicular alignment and attachment on the dentine with a mean nuclei angle and mean collagen fibre angle of approximately 60° resembling the native periodontal ligament attachment. A further in vivo testing using a surgically created rodent periodontal model highlighted the 80 µm micro-channel group's effectiveness, showing a significant increase in oblique PDL fibre attachment (72 %) and periodontal regeneration (56 %) when compared to all other groups onto the tooth root compared to control groups. Further to this, immunohistochemistry demonstrated the presence of periostin in the newly formed ligament indicating that functional regeneration occurred These findings suggest that scaffold micro-architectures of 100 µm or below can play a crucial role in directing periodontal tissue regeneration, potentially addressing a critical gap in periodontal therapy. STATEMENT OF SIGNIFICANCE: Periodontal regeneration remains a significant clinical challenge. Essential to restoring dental health and function is the proper attachment of the periodontal ligament, which is functionally oriented, to regenerated bone and cementum. Our research presents an innovative biphasic scaffold, utilizing Melt Electrowriting to systematically guide tissue growth. Distinct from existing methods, our scaffold is highly porous, adaptable, and precisely guides periodontal ligament fibre attachment to the opposing tooth root and alveolar bone interfaces, a critical step for achieving periodontal functional regeneration. Our findings not only bridge a significant gap in biomaterial driven tissue guidance but also promise more predictable outcomes for patients, marking a transformative advancement in the field.

Recent advances in additive manufacturing of patient-specific devices for dental and maxillofacial rehabilitation

OBJECTIVES

Customization and the production of patient-specific devices, tailoring the unique anatomy of each patient's jaw and facial structures, are the new frontiers in dentistry and maxillofacial surgery. As a technological advancement, additive manufacturing has been applied to produce customized objects based on 3D computerized models. Therefore, this paper presents advances in additive manufacturing strategies for patient-specific devices in diverse dental specialties.

METHODS

This paper overviews current 3D printing techniques to fabricate dental and maxillofacial devices. Then, the most recent literature (2018-2023) available in scientific databases reporting advances in 3D-printed patient-specific devices for dental and maxillofacial applications is critically discussed, focusing on the major outcomes, material-related details, and potential clinical advantages.

RESULTS

The recent application of 3D-printed customized devices in oral prosthodontics, implantology and maxillofacial surgery, periodontics, orthodontics, and endodontics are presented. Moreover, the potential application of 4D printing as an advanced manufacturing technology and the challenges and future perspectives for additive manufacturing in the dental and maxillofacial area are reported.

SIGNIFICANCE

Additive manufacturing techniques have been designed to benefit several areas of dentistry, and the technologies, materials, and devices continue to be optimized. Image-based and accurately printed patient-specific devices to replace, repair, and regenerate dental and maxillofacial structures hold significant potential to maximize the standard of care in dentistry.

The 3-dimensional printing for dental tissue regeneration: the state of the art and future challenges

Tooth loss or damage poses great threaten to oral and general health. While contemporary clinical treatments have enabled tooth restoration to a certain extent, achieving functional tooth regeneration remains a challenging task due to the intricate and hierarchically organized architecture of teeth. The past few decades have seen a rapid development of three-dimensional (3D) printing technology, which has provided new breakthroughs in the field of tissue engineering and regenerative dentistry. This review outlined the bioactive materials and stem/progenitor cells used in dental regeneration, summarized recent advancements in the application of 3D printing technology for tooth and tooth-supporting tissue regeneration, including dental pulp, dentin, periodontal ligament, alveolar bone and so on. It also discussed current obstacles and potential future directions, aiming to inspire innovative ideas and encourage further development in regenerative medicine.

Melt Electrowriting of Nylon-12 Microfibers with an Open-Source 3D Printer

This study demonstrates how either a heated flat or cylindrical collector enables defect-free melt electrowriting (MEW) of complex geometries from high melting temperature polymers. The open-source "MEWron" printer uses nylon-12 filament and combined with a heated flat or cylindrical collector, produces well-defined fibers with diameters ranging from 33 ± 4 to 95 ± 3 µm. Processing parameters for stable jet formation and minimal defects based on COMSOL thermal modeling for hardware design are optimized. The balance of processing temperature and collector temperature is achieved to achieve auxetic patterns, while showing that annealing nylon-12 tubes significantly alters their mechanical properties. The samples exhibit varied pore sizes and wall thicknesses influenced by jet dynamics and fiber bridging. Tensile testing shows nylon-12 tubes are notably stronger than poly(ε-caprolactone) ones and while annealing has limited impact on tensile strength, yield, and elastic modulus, it dramatically reduces elongation. The equipment described and material used broadens MEW applications for high melting point polymers and highlights the importance of cooling dynamics for reproducible samples.

Polycaprolactone-based scaffolds for guided tissue regeneration in periodontal therapy: A systematic review

BACKGROUND

Polycaprolactone (PCL) is a highly recognized synthetic polymer for its biocompatibility, ease of fabrication and mechanical strength in bone tissue engineering. Its applications have extended broadly, including regeneration of oral and maxillofacial lost tissues. Its usefulness has brought attention of researchers to regenerate periodontal lost tissues, including alveolar bone, periodontal ligament and cementum. The aim of this systematic review was to obtain an updated analysis of the contribution of PCL-based scaffolds in the alveolar bone regeneration process.

METHODS

This review adheres to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines for systematic reviews. A computerized search of the PubMed, EBSCO, Scielo and Web of Science databases was performed, restricting literature search to published studies in English or Spanish between January 2002 and March 2023. Database search returned 248 studies which were screened based on title, author names and publication dates.

RESULTS

Data from 17 studies were reviewed and tabulated. All studies combined PCL with other biomaterials (such as Alginate, hydroxyapatite, bioactive glass, poly (lactic-co-glycolic acid)), growth factors (BMP-2, rhCEMP1), and/or mesenchymal stromal cells (adipose-derived, bone marrow, periodontal ligament or gingiva mesenchymal stromal cells). PCL scaffolds showed higher cell viability and osteoinductive potential when combined with bioactive agents. Complementary, its degradation rates were affected by the addition or exposure to specific substances, such as: Dopamine, Cerium Oxide, PLGA and hydrogen peroxide.

CONCLUSIONS

PCL is an effective biomaterial for alveolar bone regeneration in periodontally affected teeth. It could be part of a new generation of biomaterials with improved regenerative potential.