Journal of Functional Biomaterials

18 pages, 4728 KiB

Open AccessArticle

Influence of Pontic Length on the Structural Integrity of Zirconia Fixed Partial Dentures (FPDs)

by Tareq Hajaj, Ioana Elena Lile, Ioana Veja, Florina Titihazan, Mihai Rominu, Meda Lavinia Negruțiu, Cosmin Sinescu, Andreea Codruta Novac, Serban Talpos Niculescu and Cristian Zaharia

J. Funct. Biomater. 2025, 16(4), 116; https://doi.org/10.3390/jfb16040116 - 25 Mar 2025

Abstract

Objective: This study aims to evaluate the influence of pontic length and design on the fracture resistance of zirconia fixed dental prostheses (FDPs). By assessing different span lengths under controlled mechanical loading conditions, the research seeks to provide insights into optimizing the structural [...] Read more.

Objective: This study aims to evaluate the influence of pontic length and design on the fracture resistance of zirconia fixed dental prostheses (FDPs). By assessing different span lengths under controlled mechanical loading conditions, the research seeks to provide insights into optimizing the structural integrity of zirconia dental bridges. Materials and Methods: A total of 20 zirconia bridges were fabricated and tested in vitro. Ten bridges were designed to replace a single missing molar (tooth 46), with a pontic span of 11 mm, while the remaining ten were crafted for two missing teeth (35 and 36), featuring a longer pontic span of 17 mm. The zirconia frameworks were milled using the Wieland Zenotec^® Select Hybrid system and cemented onto metal abutments with Voco Meron Plus QM resin-reinforced glass ionomer cement. The specimens were subjected to occlusal loading using a ZwickRoell ProLine Z005 testing machine at a crosshead speed of 1 mm/min until fracture occurred. Results: The mechanical testing revealed a significant correlation between pontic length and fracture resistance. The mean fracture resistance for three-unit bridges (single pontic) was 3703 N, whereas four-unit bridges (double pontic) exhibited a significantly lower resistance of 1713 N. These findings indicate that increased span length reduces the fracture resistance of zirconia restorations due to higher stress accumulation and reduced rigidity. Conclusions: This study underscores the importance of pontic length and design in determining the fracture resistance of zirconia restorations. Shorter spans exhibit greater structural stability, reinforcing the need for careful treatment planning when designing multi-unit zirconia bridges. By optimizing bridge parameters, clinicians can improve clinical outcomes and extend the longevity of zirconia prostheses in restorative dentistry. Full article

(This article belongs to the Special Issue Technologies and Materials for Application in Dental, Oral and Maxillofacial Engineering)

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20 pages, 43063 KiB

Open AccessArticle

Intramuscular Reactivity of the Modified Graphene Oxides and Their Bio-Reactivity in Aging Muscle

by Xiaoting Jian, Jiayin Wang, Jijie Hu, Yangyang Li, Qisen Wang, Han Wang, Jingwen Huang, Yu Ke and Hua Liao

J. Funct. Biomater. 2025, 16(4), 115; https://doi.org/10.3390/jfb16040115 - 25 Mar 2025

Abstract

To enhance the biocompatibility and drug delivery efficiency of graphene oxide (GO), poly(ethylene glycol) (PEG), poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), or its triblock copolymer PEG-PHBV-PEG (PPP) were used to chemically modify GO. However, it is still unknown whether non-toxic polymer-modified GO mediates muscle toxicity or triggers [...] Read more.

To enhance the biocompatibility and drug delivery efficiency of graphene oxide (GO), poly(ethylene glycol) (PEG), poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), or its triblock copolymer PEG-PHBV-PEG (PPP) were used to chemically modify GO. However, it is still unknown whether non-toxic polymer-modified GO mediates muscle toxicity or triggers intramuscular inflammation. This study aims to investigate the biological reactivity and inflammation/immune response induced by PEG, PHBV, or PPP modified GO when injected into the tibialis anterior (TA) muscle of mice prior to drug loading. The results showed that after muscle exposure, the coating of biocompatible polymers on GO is more likely to provoke muscle necrosis. Muscle regeneration was found to occur earlier and more effectively in muscle treated with hydrophilic PEG-GO and PPP-GO compared to muscle treated with hydrophobic PHBV-GO. When observing the transient muscle macrophage invasion of three modified GOs, PHBV-GO caused severe muscle necrosis in the early stage, induced a delayed peak of macrophage aggregation, and caused severe inflammatory progression. All three kinds of modified GO induced T cell aggregation to varying degrees, but PEG-GO induced early mass muscle recruitment of CD4⁺ T cells and was more sensitive to cytotoxic T cells. Based on the higher biocompatibility of PPP-GO in muscles, PPP-GO was implanted into the muscles of old or adult mice. Compared to adult mice, aged mice are more vulnerable to the stress from PPP-GO, as demonstrated by a delayed inflammatory response and muscle regeneration. Full article

(This article belongs to the Section Biomaterials for Drug Delivery)

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30 pages, 4468 KiB

Open AccessReview

Piezoelectric Nanomaterials for Cancer Therapy: Current Research and Future Perspectives on Glioblastoma

by Zayne Knight, Amalia Ruiz and Jacobo Elies

J. Funct. Biomater. 2025, 16(4), 114; https://doi.org/10.3390/jfb16040114 - 24 Mar 2025

Abstract

Cancer significantly impacts human quality of life and life expectancy, with an estimated 20 million new cases and 10 million cancer-related deaths worldwide every year. Standard treatments including chemotherapy, radiotherapy, and surgical removal, for aggressive cancers, such as glioblastoma, are often ineffective in [...] Read more.

Cancer significantly impacts human quality of life and life expectancy, with an estimated 20 million new cases and 10 million cancer-related deaths worldwide every year. Standard treatments including chemotherapy, radiotherapy, and surgical removal, for aggressive cancers, such as glioblastoma, are often ineffective in late stages. Glioblastoma, for example, is known for its poor prognosis post-diagnosis, with a median survival time of approximately 15 months. Novel therapies using local electric fields have shown anti-tumour effects in glioblastoma by disrupting mitotic spindle assembly and inhibiting cell growth. However, constant application poses risks like patient burns. Wireless stimulation via piezoelectric nanomaterials offers a safer alternative, requiring ultrasound activation to induce therapeutic effects, such as altering voltage-gated ion channel conductance by depolarising membrane potentials. This review highlights the piezoelectric mechanism, drug delivery, ion channel activation, and current technologies in cancer therapy, emphasising the need for further research to address limitations like biocompatibility in whole systems. The goal is to underscore these areas to inspire new avenues of research and overcome barriers to developing piezoelectric nanoparticle-based cancer therapies. Full article

(This article belongs to the Special Issue Medical Application of Functional Biomaterials (2nd Edition))

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22 pages, 3094 KiB

Open AccessArticle

Assessing the Effects of Surface-Stabilized Zero-Valent Iron Nanoparticles on Diverse Bacteria Species Using Complementary Statistical Models

by Brittany J. Carnathan, Dinny Stevens, Swarna Shikha, Carson Slater, Nathen Byford, Rodney X. Sturdivant, Kuzy Zarzosa, W. Evan Braswell and Christie M. Sayes

J. Funct. Biomater. 2025, 16(3), 113; https://doi.org/10.3390/jfb16030113 - 20 Mar 2025

Abstract

Nanoparticles are proposed as alternatives to traditional antimicrobial agents. By manipulating a nanoparticle’s core and surface coating, antimicrobial effects against various microbial populations can be customized, known as the “designer effect”. However, the antimicrobial properties of nanoparticle core–coating combinations are understudied; little research [...] Read more.

Nanoparticles are proposed as alternatives to traditional antimicrobial agents. By manipulating a nanoparticle’s core and surface coating, antimicrobial effects against various microbial populations can be customized, known as the “designer effect”. However, the antimicrobial properties of nanoparticle core–coating combinations are understudied; little research exists on their effects on diverse bacteria. The antimicrobial effects of surface-stabilized zero-valent iron nanoparticles (FeNPs) are particularly interesting due to their stability in water and ferromagnetic properties. This study explores the impact of FeNPs coated with three surface coatings on six diverse bacterial species. The FeNPs were synthesized and capped with L-ascorbic acid (AA), cetyltrimethylammonium bromide (CTAB), or polyvinylpyrrolidone (PVP) using a bottom-up approach. Zone of inhibition (ZOI) values, assessed through the disc diffusion assay, indicated that AA-FeNPs and CTAB-FeNPs displayed the most potent antibacterial activity. Bacteria inhibition results ranked from most sensitive to least sensitive are the following: Bacillus nealsonii > Escherichia coli > Staphylococcus aureus > Delftia acidovorans > Chryseobacterium sp. > Sphingobacterium multivorum. Comparisons using ordinal regression and generalized linear mixed models revealed significant differences in bacterial responses to the different coatings and nanoparticle concentrations. The statistical model results are in agreement, thus increasing confidence in these conclusions. This study supports the feasibility of the “designer nanoparticle” concept and offers a framework for future research. Full article

(This article belongs to the Section Antibacterial Biomaterials)

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19 pages, 6443 KiB

Open AccessArticle

Biocompatible and Antibacterial Chemical Coatings on TiZr Dental Implants

by Vlad Gabriel Vasilescu, Toma Lucian Ciocan, Andreea Mihaela Custura, Florin Miculescu, Miruna Stan, Ionela Cristina Voinea, Dumitru Dima, Florentina Ionela Bucur, Andreea Veronica Dediu-Botezatu, Marian Iulian Neacșu, Elisabeta Vasilescu and Marina Imre

J. Funct. Biomater. 2025, 16(3), 112; https://doi.org/10.3390/jfb16030112 - 20 Mar 2025

Abstract

This research aims to study the antibacterial coatings of invasive surgical medical devices, including dental implants, to reduce superficial and deep local infections over the long term. To obtain the coating without altering the initial properties of the substrate (dental implant made of [...] Read more.

This research aims to study the antibacterial coatings of invasive surgical medical devices, including dental implants, to reduce superficial and deep local infections over the long term. To obtain the coating without altering the initial properties of the substrate (dental implant made of TiZr bioalloy), simple, cost-effective, and efficient methods were employed, such as chemical deposition of silver (Ag). The deposition characteristics were analyzed using scanning electron microscopy (SEM), EDX analysis, and FT-IR infrared analysis. The in vitro testing of antimicrobial activity was conducted using the diffusion method by cultivating the bacterial strains Escherichia coli (E. coli) ATCC25922 and Staphylococcus aureus (S. aureus) ATCC25923 and measuring the diameter of the bacterial inhibition zone. Investigations and biocompatibility evaluations were performed on both uncoated and silver-coated (Ag) samples by analyzing cell viability and morphology in the presence of human fetal osteoblasts (hFOB cell line) and human gingival fibroblasts (HFIB-G cells) after 8 days of incubation. The research results confirm the biocompatibility of the coating, demonstrated by the lack of significant differences in cell density between the Ag-coated samples and the control group, as well as by the fact that the silver-coated surface effectively supports actin cytoskeleton organization, adhesion, and migration of both human osteoblasts and gingival fibroblasts. The results regarding the antibacterial efficiency of the silver implant coating indicated that the E. coli bacterial strain is more resistant than S. aureus. The resistance difference between the two bacterial strains was attributed to differences in the structure of their cell envelopes. Full article

(This article belongs to the Special Issue The Development and Future of Dental Implants)

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12 pages, 870 KiB

Open AccessReview

Class-I and Class-II Restorations with the Application of a Flowable Composite as an Intermediate Layer—A Narrative Review of Clinical Trials

by Anh Duc Nguyen, Kerstin Bitter and Christian Ralf Gernhardt

J. Funct. Biomater. 2025, 16(3), 111; https://doi.org/10.3390/jfb16030111 - 20 Mar 2025

Abstract

The objective of this review is to investigate the effect of an additional layer of flowable composite for cavity lining on the clinical outcome of direct posterior composite restorations. The PICO question (patient, intervention, comparison, and outcome) was stated as follows: Does the [...] Read more.

The objective of this review is to investigate the effect of an additional layer of flowable composite for cavity lining on the clinical outcome of direct posterior composite restorations. The PICO question (patient, intervention, comparison, and outcome) was stated as follows: Does the additional application of a flowable composite as a cavity liner improve the clinical outcome of Class-I and Class-II restorations? The electronic databases MEDLINE, Web of Science, LILAS, and BBO were assessed for identifying relevant clinical studies. After removal of duplicate records, 309 records could be identified and, after a screening of the title and abstract, 20 articles were selected for full-text analysis. Finally, six studies met the eligibility criteria and were included in this review for further investigation. Four of the included studies have a follow-up period of two years, while the other two studies had an observation period of three and seven years, respectively. No significant differences in annual failure rates were observed between restorations with and without a flowable composite liner. Consequently, the additional usage of flowable composites as a cavity liner seems to have no effect on the clinical longevity of direct composite restorations in Class-I and Class-II cavities. Therefore, the application of a flowable composite is a possible option in everyday dental clinical practice. Full article

(This article belongs to the Special Issue Advanced Biomaterials and Biotechnology: Applications in Dental Medicine—2nd Edition)

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25 pages, 2427 KiB

Open AccessReview

Dentistry Insights: Single-Walled and Multi-Walled Carbon Nanotubes, Carbon Dots, and the Rise of Hybrid Materials

by Roxana-Ionela Vasluianu, Ana Maria Dima, Livia Bobu, Alice Murariu, Ovidiu Stamatin, Elena-Raluca Baciu and Elena-Odette Luca

J. Funct. Biomater. 2025, 16(3), 110; https://doi.org/10.3390/jfb16030110 - 20 Mar 2025

Abstract

We are committed to writing this narrative review given that carbon-based nanomaterials are revolutionizing dental medicine. Since the groundbreaking discovery of carbon nanotubes in 1991, their dental applications have skyrocketed. The numbers speak for themselves: in 2024, the global carbon nanotubes market hit [...] Read more.

We are committed to writing this narrative review given that carbon-based nanomaterials are revolutionizing dental medicine. Since the groundbreaking discovery of carbon nanotubes in 1991, their dental applications have skyrocketed. The numbers speak for themselves: in 2024, the global carbon nanotubes market hit USD 1.3 billion and is set to double to USD 2.6 billion by 2029. Over the past few decades, various forms of carbon nanomaterials have been integrated into dental practices, elevating the quality and effectiveness of dental treatments. They represent a transformative advancement in dentistry, offering numerous benefits such as augmented mechanical properties, antimicrobial activity, and potential for regenerative applications. Both carbon nanotubes (CNTs) and carbon dots (CDs) are derived from carbon and integral to nanotechnology, showcasing the versatility of carbon nanostructures and delivering cutting-edge solutions across diverse domains, such as electronics, materials science, and biomedicine. CNTs are ambitiously examined for their capability to reinforce dental materials, develop biosensors for detecting oral diseases, and even deliver therapeutic agents directly to affected tissues. This review synthesizes their current applications, underscores their interdisciplinary value in bridging nanotechnology and dentistry, identifies key barriers to clinical adoption, and discusses hybrid strategies warranting further research to advance implementation. Full article

(This article belongs to the Section Dental Biomaterials)

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20 pages, 15356 KiB

Open AccessArticle

A Carbon-Based Nanomaterial with Dichotomous Effects: Antineoplastic on Oral Cancer Cells and Osteoinductive/Chondroinductive on Dental Pulp Stem Cells

by Milica Jaksic Karisik, Nataša Jović Orsini, Jelena Carkic, Milos Lazarevic, Dijana Mitić, Bojan Jokanovic, Vukoman Jokanović and Jelena Milasin

J. Funct. Biomater. 2025, 16(3), 109; https://doi.org/10.3390/jfb16030109 - 19 Mar 2025

Abstract

Background: Oral cancer is an aggressive malignancy with modest survival rates. It also causes disfigurement following surgical removal of the tumor, thus highlighting the need for new cancer treatment and tissue repair modalities. Carbon-based nanomaterials have emerged as promising tools in both anticancer [...] Read more.

Background: Oral cancer is an aggressive malignancy with modest survival rates. It also causes disfigurement following surgical removal of the tumor, thus highlighting the need for new cancer treatment and tissue repair modalities. Carbon-based nanomaterials have emerged as promising tools in both anticancer and regenerative therapies. Objectives: We aimed to synthesize a new carbon-based nanomaterial (CBN) and test its antineoplastic effects, as well as its potential regenerative capacity. Materials and Methods: A carbon nanomaterial, obtained by ball milling graphite flakes, was functionalized with polyvinylpyrrolidone (CBN/PVP). Its physicochemical properties were explored with X-ray diffraction (XRD), attenuated total reflection–Fourier transform infrared spectroscopy (ATR-FTIR), micro-Raman spectroscopy, fluorescent and scanning electron microscopy, and wettability analysis. For the antineoplastic effects investigation, oral cancer cells were treated with CBN/PVP and examined with MTT and migration assays, as well as cell-cycle and ROS production analyses. Gene expression was determined by qPCR. To examine the pro-regenerative capacity of CBN/PVP, dental pulp stem cell cultures (DPSCs) were treated with the nanomaterial and subjected to osteo- and chondro-induction. Results: Lower concentrations of CBN/PVP (50, 100 μg/mL) applied on cancer cells exerted remarkable cytotoxic effects, induced G1 cell-cycle arrest, and reduced cancer cell invasion potential by different mechanisms, including downregulation of the PI3K/AKT/mTOR pathway. In contrast, the addition of 50 µg/mL of CBN/PVP to DPSCs stimulated their survival and proliferation. CBN/PVP significantly enhanced both the osteogenic (p < 0.05) and chondrogenic (p < 0.01) induction of DPSCs. Conclusions: The novel carbon-based nanomaterial displays unique characteristics, making it suitable in anticancer and regenerative therapies concomitantly. Full article

(This article belongs to the Special Issue Recent Studies on Biomaterials for Tissue Repair and Regeneration)

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Graphical abstract

29 pages, 5047 KiB

Open AccessArticle

ZnO Nanoparticle-Infused Vaterite Coatings: A Novel Approach for Antimicrobial Titanium Implant Surfaces

by Atiđa Selmani, Scarlett Zeiringer, Ankica Šarić, Anamarija Stanković, Aleksander Učakar, Janja Vidmar, Anže Abram, Branka Njegić Džakula, Jasminka Kontrec, Anamarija Zore, Klemen Bohinc, Eva Roblegg and Nives Matijaković Mlinarić

J. Funct. Biomater. 2025, 16(3), 108; https://doi.org/10.3390/jfb16030108 - 19 Mar 2025

Abstract

Loss of implant function is a common complication in orthopaedic and dental surgery. Among the primary causes of implant failure are peri-implant infections which often result in implant removal. This study demonstrates the development of a new antimicrobial titanium coating with ZnO nanoparticles [...] Read more.

Loss of implant function is a common complication in orthopaedic and dental surgery. Among the primary causes of implant failure are peri-implant infections which often result in implant removal. This study demonstrates the development of a new antimicrobial titanium coating with ZnO nanoparticles of various sizes and morphologies immobilised in poly(allylamine hydrochloride) and alginate multilayers, combined with epitaxially grown vaterite crystals. The coated samples were characterised with various methods (FTIR, XRD, SEM) and surface properties were evaluated via water contact angle and surface charge measurements. Zinc ion release was quantified using ICP-MS. The antimicrobial efficacy of the coatings was tested against Staphylococcus aureus, Staphylococcus epidermidis, and Candida albicans while the biocompatibility was tested with preosteoblast cells (MC3T3-E1). Results demonstrated the successful preparation of a calcium carbonate/ZnO composite coating with epitaxially grown vaterite on titanium surfaces. The Zn ions released from ZnO nanoparticles dramatically influenced the morphology of vaterite where a new flower-like morphology was observed. The coated titanium surfaces exhibited robust antimicrobial activity, achieving over 90% microbial viability reduction for Staphylococcus aureus, Staphylococcus epidermidis, and Candida albicans. Importantly, the released Zn²⁺ concentrations remained below the cytotoxicity limit for MC3T3-E1 cells, showing potential for safe and effective implant applications. Full article

(This article belongs to the Section Antibacterial Biomaterials)

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15 pages, 5359 KiB

Open AccessArticle

Biomechanical Evaluation of a Novel Non-Engaging Abutment and Screw in Internal Implant Systems: Comparative Fatigue and Load Testing

by Su-Min Cho, Soo-Hwan Byun, So-Yee Ahn, Hyun-Sook Han, Sung-Woon On, Sang-Yoon Park, Sang-Min Yi, In-Young Park, Byoung-Eun Yang and Lee-Kyoung Kim

J. Funct. Biomater. 2025, 16(3), 107; https://doi.org/10.3390/jfb16030107 - 19 Mar 2025

Abstract

Dental implants rely on precise prosthetic design and biomechanical stability to ensure long-term success. This study evaluates the mechanical performance of non-engaging abutments in multi-unit combined screw- and cement-retained prostheses (CSCRP) using two internal implant systems: the BlueDiamond (BD) and AnyOne (AO) systems. [...] Read more.

Dental implants rely on precise prosthetic design and biomechanical stability to ensure long-term success. This study evaluates the mechanical performance of non-engaging abutments in multi-unit combined screw- and cement-retained prostheses (CSCRP) using two internal implant systems: the BlueDiamond (BD) and AnyOne (AO) systems. Unlike conventional implant systems that utilize the same type of screw for both engaging and non-engaging abutments, the BD system employs a distinct screw design for non-engaging abutments. A total of 80 implants were tested, with 40 in each group. Mechanical testing included static compressive load and fatigue tests following ISO 14801 standards. The BD system demonstrated significantly higher compressive strength (326.32 kgf vs. 231.82 kgf, p < 0.001) and 23.4% greater fatigue strength compared to the AO system. Precision fit analysis confirmed no significant deformation, microcracks, or fractures after 5 million loading cycles. These findings suggest that the BD system’s unique screw design for non-engaging abutments contributes to improved mechanical performance and durability. Further clinical studies are needed to assess the long-term implications of this design on prosthetic stability and implant longevity. Full article

(This article belongs to the Special Issue Advanced Biomaterials and Oral Implantology—3rd Edition)

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15 pages, 5200 KiB

Open AccessArticle

Designing Superhydrophilic 3D Porous Surfaces on Polyetherketoneketone Surfaces to Promote Biocompatibility

by Hui-Ching Lin, Chiang-Sang Chen, Kai-Yi Lin, Ya-Lin Huang, Hao-Hsiang Hsu, Yu-Lin Kuo, Wei-Cheng Chen and Her-Hsiung Huang

J. Funct. Biomater. 2025, 16(3), 106; https://doi.org/10.3390/jfb16030106 - 14 Mar 2025

Abstract

Polyetherketoneketone (PEKK) exhibits satisfactory mechanical properties and biocompatibility, with an elastic modulus closely resembling that of natural bone. This property reduces the stress-shielding effect associated with bone implants. However, the biological inertness of the PEKK surface remains a significant limitation for its application [...] Read more.

Polyetherketoneketone (PEKK) exhibits satisfactory mechanical properties and biocompatibility, with an elastic modulus closely resembling that of natural bone. This property reduces the stress-shielding effect associated with bone implants. However, the biological inertness of the PEKK surface remains a significant limitation for its application in bone tissue engineering. The objective of this study was to create a superhydrophilic 3D porous structure on the surface of PEKK to enhance biocompatibility, in terms of vascularization and bone remodeling. A combination of mechanical, chemical, and physical surface treatments was employed to modify the PEKK surface. Initially, mechanical sandblasting was used to create a rough surface to promote mechanical interlocking with bone tissue. Subsequently, chemical acid etching and physical low-temperature atmospheric plasma cleaning were applied to develop a superhydrophilic 3D porous surface. The modified surfaces were characterized for morphology, roughness, hydrophilicity, and functional groups. Cellular responses, including vascularization and bone remodeling, were evaluated to assess the potential for improved biocompatibility. The combination of acid etching and low-temperature atmospheric plasma cleaning, with or without prior sandblasting, successfully created a superhydrophilic 3D porous structure on the PEKK surface. This modified surface enhanced the tube formation in human umbilical vein endothelial cells. It also promoted the adhesion and mineralization of human bone marrow mesenchymal stem cells and slightly reduced tartrate-resistant acid phosphatase expression and F-actin ring size in mouse macrophage cells. This study introduces an innovative and effective surface modification strategy for PEKK surface, combining mechanical, chemical, and physical treatments to enhance biocompatibility. The modified PEKK surface promotes angiogenic and osteogenic responses while slightly inhibiting osteoclastic activity, making it a potential alternative for dental and orthopedic PEKK implant applications. Full article

(This article belongs to the Collection Feature Papers in Bone Biomaterials)

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36 pages, 3511 KiB

Open AccessReview

Three-Dimensional Bioprinting for Intervertebral Disc Regeneration

by Md Amit Hasan Tanvir, Md Abdul Khaleque, Junhee Lee, Jong-Beom Park, Ga-Hyun Kim, Hwan-Hee Lee and Young-Yul Kim

J. Funct. Biomater. 2025, 16(3), 105; https://doi.org/10.3390/jfb16030105 - 14 Mar 2025

Abstract

The rising demand for organ transplants and the need for precise tissue models have positioned the in vitro biomanufacturing of tissues and organs as a pivotal area in regenerative treatment. Considerable development has been achieved in growing tissue-engineered intervertebral disc (IVD) scaffolds, designed [...] Read more.

The rising demand for organ transplants and the need for precise tissue models have positioned the in vitro biomanufacturing of tissues and organs as a pivotal area in regenerative treatment. Considerable development has been achieved in growing tissue-engineered intervertebral disc (IVD) scaffolds, designed to meet stringent mechanical and biological compatibility criteria. Among the cutting-edge approaches, 3D bioprinting stands out due to its unparalleled capacity to organize biomaterials, bioactive molecules, and living cells with high precision. Despite these advancements, polymer-based scaffolds still encounter limitations in replicating the extracellular matrix (ECM)-like environment, which is fundamental for optimal cellular activities. To overcome these challenges, integrating polymers with hydrogels has been recommended as a promising solution. This combination enables the advancement of porous scaffolds that nurture cell adhesion, proliferation, as well as differentiation. Additionally, bioinks derived from the decellularized extracellular matrix (dECM) have exhibited potential in replicating biologically relevant microenvironments, enhancing cell viability, differentiation, and motility. Hydrogels, whether derived from natural sources involving collagen and alginate or synthesized chemically, are highly valued for their ECM-like properties and superior biocompatibility. This review will explore recent advancements in techniques and technologies for IVD regeneration. Emphasis will be placed on identifying research gaps and proposing strategies to bridge them, with the goal of accelerating the translation of IVDs into clinical applications. Full article

(This article belongs to the Special Issue Three-Dimensional-Printable Biomaterials for Bone Regeneration)

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43 pages, 1876 KiB

Open AccessReview

Evolution of Dental Resin Adhesives—A Comprehensive Review

by Waad Khalid Alomran, Mohammed Zahedul Islam Nizami, Hockin H. K. Xu and Jirun Sun

J. Funct. Biomater. 2025, 16(3), 104; https://doi.org/10.3390/jfb16030104 - 14 Mar 2025

Abstract

This comprehensive review of dental resin adhesives explores their historical development, key components, recent innovations, and potential future directions, highlighting a dynamic and continually advancing field. From Buonocore’s breakthrough acid-etching technique and Bowen’s pioneering dental resin invention, successive generations of clinicians and scientists [...] Read more.

This comprehensive review of dental resin adhesives explores their historical development, key components, recent innovations, and potential future directions, highlighting a dynamic and continually advancing field. From Buonocore’s breakthrough acid-etching technique and Bowen’s pioneering dental resin invention, successive generations of clinicians and scientists have pushed forward the technological and materials development for secure bonding, while preserving dental tissues. The review discusses the substantial advances in improving adhesive reliability, enabling more conservative treatment approaches. It also delves into enhancing fundamental adhesive components and their synergistic combinations. Recent innovations, including biostable and functional resins, nanotechnology, and bioactive components, address persistent challenges such as durability, antimicrobial efficacy, and therapeutic functionality. Emerging technologies, such as digital dentistry, artificial intelligence, and bioinspired adhesives, portend an exciting and promising future for dental adhesives. This review underscores the critical role of ongoing research in developing biocompatible, multifunctional, and durable adhesives. It aims to support dental professionals and researchers by providing a comprehensive understanding of the dynamic progression of dental adhesives, inspiring continued innovation and excellence in restorative dentistry. Full article

(This article belongs to the Special Issue Recent Advances in Dental Resin Composites)

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22 pages, 5628 KiB

Open AccessArticle

Effect of Pixel Offset Adjustments for XY Plane Dimensional Compensation in Digital Light Processing 3D Printing on the Surface Trueness and Fit of Zirconia Crowns

by KeunBaDa Son, Ji-Min Lee, Kyoung-Jun Jang, Sang-Kyu Lee, Jun Ho Hwang, Jong Hoon Lee, Hyun Deok Kim, So-Yeun Kim and Kyu-Bok Lee

J. Funct. Biomater. 2025, 16(3), 103; https://doi.org/10.3390/jfb16030103 - 14 Mar 2025

Abstract

This study aimed to evaluate the effect of pixel offset adjustments in digital light processing (DLP) three-dimensional (3D) printing on the marginal and internal fit and surface trueness of zirconia crowns. Zirconia crowns were designed using dental computer-aided design software (Dentbird; Imagoworks) and [...] Read more.

This study aimed to evaluate the effect of pixel offset adjustments in digital light processing (DLP) three-dimensional (3D) printing on the marginal and internal fit and surface trueness of zirconia crowns. Zirconia crowns were designed using dental computer-aided design software (Dentbird; Imagoworks) and fabricated with a vat photopolymerization DLP 3D printer (TD6+; 3D Controls) under three pixel offset conditions (−1, 0, and 1). Pixel offset refers to the controlled modification of the outermost pixels in the XY plane during printing to compensate for potential dimensional inaccuracies. The marginal and internal fit was assessed using a triple-scan protocol and quantified using root mean square (RMS) values. Surface trueness was evaluated by measuring RMS, positive and negative errors between the designed and fabricated crowns. Statistical analyses included one-way ANOVA and Pearson correlation analysis (α = 0.05). The Pixel offset had a significant effect on fit accuracy and surface trueness (p < 0.05). Higher pixel offsets increased marginal discrepancies (p = 0.004), with the marginal gap exceeding 120 µm at a pixel offset of 1 (114.5 ± 14.6 µm), while a pixel offset of −1 (85.5 ± 18.6 µm) remained within acceptable limits (p = 0.003). Surface trueness worsened with increasing pixel offset, showing greater positive errors (p < 0.001). Optimizing pixel offset in DLP 3D printing is crucial to ensuring clinically acceptable zirconia crowns. Improper settings may increase marginal discrepancies and surface errors, compromising restoration accuracy. Full article

(This article belongs to the Special Issue Advanced 3D Printing Biomaterials)

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10 pages, 3362 KiB

Open AccessCommunication

Preclinical Performance of a Novel Dental Implant Design Reducing Mechanical Stress in Cortical Bone

by Carolin Erbel, Matthias W. Laschke, Tanja Grobecker-Karl and Matthias Karl

J. Funct. Biomater. 2025, 16(3), 102; https://doi.org/10.3390/jfb16030102 - 14 Mar 2025

Abstract

This animal study compared the healing performance of a novel implant design characterized by a shift in thread geometry and core diameter with two different surfaces with that of an apically tapered implant. Test Bioactive (n = 9), Test Porous (n = 7) [...] Read more.

This animal study compared the healing performance of a novel implant design characterized by a shift in thread geometry and core diameter with two different surfaces with that of an apically tapered implant. Test Bioactive (n = 9), Test Porous (n = 7) and Control (n = 8) implants were placed in the mandibles of minipigs. Following healing, bone samples were harvested for determining bone-to-implant contact (BIC) and marginal bone loss (MBL). Comparative statistics were based on Levene’s test, Shapiro–Wilk tests, the Kruskal–Wallis test and Wilcoxon tests with Holm correction (α = 0.05). The mean undersizing of the osteotomy was 0.15 mm for Control, while in the test groups 0.33 mm and 0.34 mm were calculated. Insertion torques ranged from 61.5 Ncm (Control) to 76.1 Ncm (Test Bioactive). Maximum BIC was seen in Test Porous with 55.83%, while Test Bioactive showed only 48.11%. MBL was 4.1 mm in Test Bioactive, while Test Porous and Control exhibited 2.8 mm. No significant differences between the implant groups were observed (p > 0.05). Despite greater undersizing, the novel implant type performed comparably to the established Control implants. The rougher surface of the bioactive implants increased the insertion torque and led to more MBL. Full article

(This article belongs to the Section Dental Biomaterials)

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15 pages, 5530 KiB

Open AccessArticle

Formulating Mechanically Robust Composite Restorative Materials for High Performance

by Austyn Salazar, Natalie Anderson and Jeffrey Stansbury

J. Funct. Biomater. 2025, 16(3), 101; https://doi.org/10.3390/jfb16030101 - 13 Mar 2025

Abstract

Although dental resin composite restoratives offer a widely used direct-placement treatment option aimed at replacing the form and function of a natural tooth, there are several clinically relevant performance aspects of these materials that can be improved. The formulation of the resin matrix [...] Read more.

Although dental resin composite restoratives offer a widely used direct-placement treatment option aimed at replacing the form and function of a natural tooth, there are several clinically relevant performance aspects of these materials that can be improved. The formulation of the resin matrix phase of dental composites for high-efficiency photopolymerization leading to polymers with excellent mechanical properties has always been a challenge that is addressed here through the use of structurally new and more reactive monomers as well as the formation of polymer networks that incorporate non-covalent reinforcing interactions. The purpose of this study was to validate that a set of tetraurethane diacrylates (TUDAs) with a novel configuration of their urethane linkages in coordination with acidic comonomers could be devised to obtain highly robust new composite materials. Due to the novel molecular design, this exploratory approach was conducted using reaction kinetics and three-point bend testing to assess the performance. Conversion and mechanical properties were measured to refine these formulations prior to the addition of filler. The initial formulations demonstrated outstanding dry mechanical test results that subsequently showed a major intolerance to water storage, which led to a model study using urethane diacrylate (UDA) followed by the addition of hydrophobic TUDA monomers. Once the resin formulations were optimized, silane-treated particulate filler was added to determine the effectiveness as composite materials. The final formulation used a hydrophobic, aromatic TUDA along with 4-methacryloxyethyl trimellitic anhydride (4-META) as a latent acidic comonomer and a mixture of acrylic acid (AA) and methacrylic acid (MAA). This formulation achieves a very high level of both reactivity and mechanical properties relative to current dental composite restoratives. Full article

(This article belongs to the Special Issue State-of-the-Art Dental Adhesives and Restorative Composites)

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22 pages, 4851 KiB

Open AccessArticle

Porous Hydrogels Prepared by Two-Step Gelation Method for Bone Regeneration

by Yongzhi Li, Jiangshan Liu, Jiawei Wei, Li Yuan, Jiaxin Hu, Siluo Dai, Yubao Li and Jidong Li

J. Funct. Biomater. 2025, 16(3), 100; https://doi.org/10.3390/jfb16030100 - 13 Mar 2025

Abstract

Hierarchical porous hydrogels possess advantageous characteristics that facilitate cell adhesion, promote tissue growth, and enhance angiogenesis and osteogenesis. In this study, porous composite hydrogels were successfully prepared by a two-step gelation method with sodium alginate (SA), gelatin (GEL), and calcium hydrogen phosphate (DCP) [...] Read more.

Hierarchical porous hydrogels possess advantageous characteristics that facilitate cell adhesion, promote tissue growth, and enhance angiogenesis and osteogenesis. In this study, porous composite hydrogels were successfully prepared by a two-step gelation method with sodium alginate (SA), gelatin (GEL), and calcium hydrogen phosphate (DCP) as the main components. The fabricated porous hydrogels initially featured small pores (approximately 60 μm), and gradually evolved to large pores (exceeding 250 μm) during the gradual degradation in the cellular microenvironment. In vitro cell culture experiments indicated that these hydrogels could enhance the proliferation and osteogenic differentiation of bone marrow mesenchymal stem cells due to the hierarchical porous structure and the incorporation of DCP. Subcutaneous implantation and cranial defect repair experiments in Sprague−Dawley rats further confirmed that the small initial pore size of hydrogel scaffolds can provide more sites for cell adhesion. Additionally, the gradual degradation to form large pores was conducive to cell/tissue growth and blood vessel formation, ultimately being beneficial for vascularized bone regeneration. In summary, this study proposes an innovative strategy for developing porous hydrogels with gradual degradation for functional bone regeneration. Full article

(This article belongs to the Section Bone Biomaterials)

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14 pages, 3056 KiB

Open AccessArticle

Spatial Platform for Periodontal Ligament Angulation and Regeneration: In Vivo Pilot Study

by Min Guk Kim, Do-Yeon Kim, Hyoung-Gon Ko, Jin-Seok Byun, Joong-Hyun Kim and Chan Ho Park

J. Funct. Biomater. 2025, 16(3), 99; https://doi.org/10.3390/jfb16030099 - 13 Mar 2025

Abstract

The periodontal ligament (PDL) is a fibrous connective tissue that anchors the tooth-root surface to the alveolar bone with specific orientations. It plays a crucial role in functional restoration, optimal position stabilities, biomechanical stress transmission, and appropriate tissue remodeling in response to masticatory [...] Read more.

The periodontal ligament (PDL) is a fibrous connective tissue that anchors the tooth-root surface to the alveolar bone with specific orientations. It plays a crucial role in functional restoration, optimal position stabilities, biomechanical stress transmission, and appropriate tissue remodeling in response to masticatory loading conditions. This pilot study explored spatial microarchitectures to promote PDL orientations while limiting mineralized tissue formation. A computer-designed perio-complex scaffold was developed with two parts: (1) PDL-guiding architectures with defined surface topography and (2) a bone region with open structures. After SEM analysis of micropatterned topographies on PDL-guiding architectures, perio-complex scaffolds were transplanted into two-wall periodontal defects in the canine mandible. Despite the limited bone formation at the 4-week timepoint, bone parameters in micro-CT quantifications showed statistically significant differences between the no-scaffold and perio-complex scaffold transplantation groups. Histological analyses demonstrated that the PDL-guiding architecture regulated fiber orientations and facilitated the functional restoration of PDL bundles in immunohistochemistry with periostin and decorin (DCN). The perio-complex scaffold exhibited predictable and controlled fibrous tissue alignment with specific angulations, ensuring spatial compartmentalization for PDL tissues and bone regenerations. These findings highlighted that the perio-complex scaffold could serve as an advanced therapeutic approach to contribute periodontal tissue regeneration and functional restoration in tooth-supporting structures. Full article

(This article belongs to the Special Issue Advanced Biomaterials for Periodontal Regeneration)

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15 pages, 3413 KiB

Open AccessArticle

Hybridization Chain Reaction-Enhanced Ultrasensitive Electrochemical Analysis of miRNAs with a Silver Nano-Reporter on a Gold Nanostructured Electrode Array

by Bin Wang, Huiqiang Ma, Mingxing Zhou, Xian Huang, Ying Gan and Hong Yang

J. Funct. Biomater. 2025, 16(3), 98; https://doi.org/10.3390/jfb16030098 - 12 Mar 2025

Abstract

Abnormal expression of miRNAs is associated with the occurrence and progression of cancer and other diseases, making miRNAs essential biomarkers for disease diagnosis and prognosis. However, the intrinsic properties of miRNAs, such as short length, low abundance, and high sequence homology, represent great [...] Read more.

Abnormal expression of miRNAs is associated with the occurrence and progression of cancer and other diseases, making miRNAs essential biomarkers for disease diagnosis and prognosis. However, the intrinsic properties of miRNAs, such as short length, low abundance, and high sequence homology, represent great challenges for fast and accurate miRNA detection in clinics. Herein, we developed a novel hybridization chain reaction (HCR)-based electrochemical miRNAs chip (e-miRchip), featured with gold nanostructured electrodes (GNEs) and silver nanoparticle reporters (AgNRs), for sensitive and multiplexed miRNA detection. AgNRs were synthesized and applied on the e-miRchip to generate strong redox signals in the presence of miRNA. The stem–loop capture probe was covalently immobilized on the GNEs, and was opened upon miRNA hybridization to consequently trigger the HCR for signal amplification. The multiple long-repeated DNA helix generated by HCR provides the binding sites for the AgNRs, contributing to the amplification of the electrochemical signals of miRNA hybridization. To optimize the detection sensitivity, GNEs with three distinct structures were electroplated, in which flower-like GNEs were found to be the best electrode morphology for miRNAs analysis. Under optimal conditions, the HCR-based e-miRchip showed an excellent detection performance with an LOD of 0.9 fM and a linear detection range from 1 fM to 10 pM. Moreover, this HCR-based e-miRchip platform was able to effectively distinguish miRNAs from the one- or two-base mismatches. This HCR-based e-miRchip holds great potential as a highly efficient and promising miRNA detection platform for the diagnosis and prognosis of cancer and other diseases in the future. Full article

(This article belongs to the Special Issue Women’s Special Issue Series: Functional Biomaterials (2nd Edition))

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Journal of Functional Biomaterials

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