Craniofacial therapy: advanced local therapies from nano-engineered titanium implants to treat craniofacial conditions

Constructing an Injectable Multifunctional Antibacterial Hydrogel Adhesive to Seal Complex Interfaces Post-Dental Implantation to Improve Soft Tissue Integration

Soft tissue integration (STI) around dental implants determines their long-term success, and the key is to immediately construct a temporary soft tissue-like barrier to prevent bacterial invasion after implantation and then, promote STI. In response to this need, an injectable multi-crosslinked hydrogel (MCH) with abilities of self-healing, anti-swelling, degradability, and dry/wet adhesion to soft tissue/titanium is developed using gallic acid-graft-chitosan, oxidized sodium alginate, gelatin, and Cu2+ with water and borax solution as solvents, whose properties can be controlled by adjusting its composition and ratio. MCH can not only immediately build a sealing barrier to block the bacterial invasion in the oral simulation environment but also deliver outstanding antibacterial efficacy through the synergism of trapping bacteria and releasing bactericidal agents such as chitosan, gallic acid, aldehyde, and Cu2+. Moreover, MCH has an adjustable ROS-scavenging ability imparted by gallic acid, chitosan, and gelatin to reduce inflammation and can control the release of Cu2+. Based on these, it is believed that by injecting MCH around implants (percutaneous/transmucosal) after surgery, a universal non-aggressive strategy to promote STI can be developed for long-term implant success.

Unlocking Osseointegration: Surface Engineering Strategies for Enhanced Dental Implant Integration

Tooth loss is a prevalent problem faced by individuals of all ages across the globe. Various biomaterials, such as metals, bioceramics, polymers, composites of ceramics and polymers, etc., have been used for the manufacturing of dental implants. The success of a dental implant primarily depends on its osseointegration rate. The current surface modification techniques fail to imbibe the basics of tooth development, which can impart better mineralization and osseointegration. This can be improved by developing an understanding of the developmental pathways of dental tissue. Stimulating the correct signaling pathways through inductive material systems can bring about a paradigm shift in dental implant materials. The current review focuses on the developmental pathway and mineralization process that happen during tooth formation and how surface modifications can help in biomimetic mineralization, thereby enhancing osseointegration. We further describe the effect of dental implant surface modifications on mineralization, osteoinduction, and osseointegration; both in vitro and in vivo. The review will help us to understand the natural process of teeth development and mineralization and how the surface properties of dental implants can be further improved to mimic teeth development, in turn increasing osseointegration.

Photoelectron Therapy Preventing the Formation of Bacterial Biofilm on Titanium Implants

The exogenous bacterial infection and formation of biofilm on the surface of titanium implants can affect the adhesion, proliferation, and differentiation of cells associated with osteogenesis, ultimately leading to surgical failure. This study focuses on two critical stages for biofilm formation: i) bacterial adhesion and aggregation, ii) growth and proliferation. The titanium with well-organized titania nanotube arrays is first modified by nitrogen dopants, then loaded with CuFeSe2 nanoparticles to form a p-n heterojunction. Such heterojunction can effectively separate the electrons and holes generated by CuFeSe2 under NIR excitation, where CuFeSe2 serves as an electron acceptor from adherent bacteria, thus disrupting the respiratory chain and eventually affecting the metabolism. Combined with the released ions in solution and photothermal effect, the formation of bacterial biofilm on the surface of titanium implants is prevented on both stages.

D-arginine-loaded pH-responsive mesoporous silica nanoparticles enhances the efficacy of water jet therapy in decontaminating biofilm-coated titanium surface

Peri-implantitis, caused by bacterial biofilm on dental implants, leads to bone loss and tissue inflammation, ultimately causing oral health decline. Traditional methods to remove biofilm are ineffective in promoting reosseointegration on implant surfaces. This phenomenon can be attributed to two factors: incomplete removal of biofilm from hard-to-reach areas and alterations in the physicochemical properties of implant surfaces caused by decontamination procedures. To address this problem, we developed D-arginine-loaded chitooligosaccharide-capped pH-responsive mesoporous silica nanoparticles (Dar@MSN-COS) for improving the efficacy of decontamination of Water Jet (WJ). Dar@MSN-COS particles exhibit a targeted approach towards the extracellular polymeric substance (EPS) in order to disrupt the biofilm, and possess the capability to infiltrate confined areas between implant screws. Following this, the WJ treatment effectively removed residual biofilm and demonstrated improved cleaning efficacy. Furthermore, the decontamination of the Dar@MSN-COS combination with WJ promotes effective cell cytocompatibility on the titanium surface. The results of mechanistic experiments indicate that Dar@MSN-COS may act on biofilms by releasing a significant quantity of reactive oxygen species (ROS), suggesting it as a key contributing factor. In summary, our novel therapeutic protocol shows promise as an alternative solution for addressing the clinically complex aspects of peri-implantitis.

Wirelessly Actuated Microfluidic Pump and Valve for Controlled Liquid Delivery in Dental Implants

Enabling minimally invasive and precise control of liquid release in dental implants is crucial for therapeutic functions such as delivering antibiotics to prevent biofilm formation, infusing stem cells to promote osseointegration, and administering other biomedicines. However, achieving controllable liquid cargo release in dental implants remains challenging due to the lack of wireless and miniaturized fluidic control mechanisms. Here wireless miniature pumps and valves that allow remote activation of liquid cargo delivery in dental implants, actuated and controlled by external magnetic fields (<65 mT), are reported. A magnet-screw mechanism in a fluidic channel to function as a piston pump, alongside a flexible magnetic valve designed to open and close the fluidic channel, is proposed. The mechanisms are showcased by storing and releasing of liquid up to 52 µL in a dental implant. The liquid cargos are delivered directly to the implant-bone interface, a region traditionally difficult to access. On-demand liquid delivery is further showed by a metal implant inside both dental phantoms and porcine jawbones. The mechanisms are promising for controllable liquid release after implant placement with minimal invasion, paving the way for implantable devices that enable long-term and targeted delivery of therapeutic agents in various bioengineering applications.

Engineering of Bioresorbable Polymers for Tissue Engineering and Drug Delivery Applications

Herein, the recent advances in the development of resorbable polymeric-based biomaterials, their geometrical forms, resorption mechanisms, and their capabilities in various biomedical applications are critically reviewed. A comprehensive discussion of the engineering approaches for the fabrication of polymeric resorbable scaffolds for tissue engineering, drug delivery, surgical, cardiological, aesthetical, dental and cardiovascular applications, are also explained. Furthermore, to understand the internal structures of resorbable scaffolds, representative studies of their evaluation by medical imaging techniques, e.g., cardiac computer tomography, are succinctly highlighted. This approach provides crucial clinical insights which help to improve the materials' suitable and viable characteristics for them to meet the highly restrictive medical requirements. Finally, the aspects of the legal regulations and the associated challenges in translating research into desirable clinical and marketable materials of polymeric-based formulations, are presented.

Application of advanced surface modification techniques in titanium-based implants: latest strategies for enhanced antibacterial properties and osseointegration

Titanium-based implants, renowned for their excellent mechanical properties, corrosion resistance, and biocompatibility, have found widespread application as premier implant materials in the medical field. However, as bioinert materials, they often face challenges such as implant failure caused by bacterial infections and inadequate osseointegration post-implantation. Thus, to address these issues, researchers have developed various surface modification techniques to enhance the surface properties and bioactivity of titanium-based implants. This review aims to outline several key surface modification methods for titanium-based implants, including acid etching, sol-gel method, chemical vapor deposition, electrochemical techniques, layer-by-layer self-assembly, and chemical grafting. It briefly summarizes the advantages, limitations, and potential applications of these technologies, presenting readers with a comprehensive perspective on the latest advances and trends in the surface modification of titanium-based implants.

Recent development and applications of electrodeposition biocoatings on medical titanium for bone repair

Bioactive coatings play a crucial role in enhancing the osseointegration of titanium implants for bone repair. Electrodeposition offers a versatile and efficient technique to deposit uniform coatings onto titanium surfaces, endowing implants with antibacterial properties, controlled drug release, enhanced osteoblast adhesion, and even smart responsiveness. This review summarizes the recent advancements in bioactive coatings for titanium implants used in bone repair, focusing on various electrodeposition strategies based on material-structure synergy. Firstly, it outlines different titanium implant materials and bioactive coating materials suitable for bone repair. Then, it introduces various electrodeposition methods, including electrophoretic deposition, anodization, micro-arc oxidation, electrochemical etching, electrochemical polymerization, and electrochemical deposition, discussing their applications in antibacterial, osteogenic, drug delivery, and smart responsiveness. Finally, it discusses the challenges encountered in the electrodeposition of coatings for titanium implants in bone repair and potential solutions.

Application of nanoparticles as surface modifiers of dental implants for revascularization/regeneration of bone

BACKGROUND

Osseointegrated dental implants are widely established as a first-choice treatment for the replacement of missing teeth. Clinical outcomes are however often compromised by short or longer-term biological complications and pathologies. Nanoparticle-coated materials represent a very active research area with the potential to enhance clinical outcomes and reduce complications of implant therapy. This scoping review aimed to summarize current research on various types of nanoparticles (NPs) used as surface modifiers of dental implants and their potential to promote biological and clinical outcomes.

METHODS

A systematic electronic search was conducted in SCOPUS, PubMed and Google Scholar aiming to identify in vivo, in situ, or in vitro studies published between 2014 and 2024. Inclusion and exclusion criteria were determined and were described in the methods section.

RESULTS

A total of 169 articles (44 original papers from Scopus and PubMed, and 125 articles from Google Scholar) were identified by the electronic search. Finally, 30 studies fit the inclusion criteria and were further used in this review. The findings from the selected papers suggest that nanoparticle-coated dental implants show promising results in enhancing bone regeneration and promoting angiogenesis around the implant site. These effects are due to the unique physicochemical properties of nanoparticle-coated implants and the controlled release of bioactive molecules from nanoparticle-modified surfaces.

CONCLUSION

Nanoscale modifications displayed unique properties which could significantly enhance the properties of dental implants and further accelerate revascularization, and osseointegration while facilitating early implant loading. Yet, since many of these findings were based on in-vitro/in-situ systems, further research is required before such technology reaches clinical application.

Surface-Engineered Titanium with Nanoceria to Enhance Soft Tissue Integration Via Reactive Oxygen Species Modulation and Nanotopographical Sensing

The design of implantable biomaterials involves precise tuning of surface features because the early cellular fate on such engineered surfaces is highly influenced by many physicochemical factors [roughness, hydrophilicity, reactive oxygen species (ROS) responsiveness, etc.]. Herein, to enhance soft tissue integration for successful implantation, Ti substrates decorated with uniform layers of nanoceria (Ce), called Ti@Ce, were optimally developed by a simple and cost-effective in situ immersion coating technique. The characterization of Ti@Ce shows a uniform Ce distribution with enhanced roughness (∼3-fold increase) and hydrophilicity (∼4-fold increase) and adopted ROS-scavenging capacity by nanoceria coating. When human gingival fibroblasts were seeded on Ti@Ce under oxidative stress conditions, Ti@Ce supported cellular adhesion, spreading, and survivability by its cellular ROS-scavenging capacity. Mechanistically, the unique nanocoating resulted in higher expression of amphiphysin (a nanotopology sensor), paxillin (a focal adhesion protein), and cell adhesive proteins (collagen-1 and fibronectin). Ti@Ce also led to global chromatin condensation by decreasing histone 3 acetylation as an early differentiation feature. Transcriptome analysis by RNA sequencing confirmed the chromatin remodeling, antiapoptosis, antioxidant, cell adhesion, and TGF-β signaling-related gene signatures in Ti@Ce. As key fibroblast transcription (co)factors, Ti@Ce promotes serum response factor and MRTF-α nucleus localization. Considering all of this, it is proposed that the surface engineering approach using Ce could improve the biological properties of Ti implants, supporting their functioning at soft tissue interfaces and utilization as a bioactive implant for clinical conditions such as peri-implantitis.

A Facile Surface Modification Scheme for Medical-Grade Titanium and Polypropylene Using a Novel Mussel-Inspired Biomimetic Polymer with Cationic Quaternary Ammonium Functionalities for Antibacterial Application

Medical device-associated infection remains a critical problem in the healthcare setting. Different clinical- or device-related methods have been attempted to reduce the infection rate. Among these approaches, creating a surface with bactericidal cationic functionality has been proposed. To do so, a sophisticated multi-step chemical procedure would be needed. Instead, a simple immersion approach was utilized in this investigation to render the titanium and polypropylene surface with the quaternary ammonium functionality by using a mussel-inspired novel lab-synthesized biomimetic catechol-terminated polymer, PQA-C8. The chemical oxidants, CuSO4/H2O2, as well as dopamine, were added into the novel PQA-C8 polymer immersion solution for one-step surface modification. Additionally, a two-step immersion scheme, in which the polypropylene substrate was first immersed in the dopamine solution and then in the PQA-C8 solution, was also attempted. Surface analysis results indicated the surface characteristics of the modified substrates were affected by the immersion solution formulation as well as the procedure utilized. The antibacterial assay has shown the titanium substrates modified by the one-step dopamine + PQA-C8 mixtures with the oxidants added and the polypropylene modified by the two-step scheme exhibited bacterial reduction percentages greater than 90% against both Gram-positive S. aureus and Gram-negative E. coli and these antibacterial substrates were non-cytotoxic.

Manganese Enhances the Osteogenic Effect of Silicon-Hydroxyapatite Nanowires by Targeting T Lymphocyte Polarization

Biomaterials encounter considerable challenges in extensive bone defect regeneration. The amelioration of outcomes may be attainable through the orchestrated modulation of both innate and adaptive immunity. Silicon-hydroxyapatite, for instance, which solely focuses on regulating innate immunity, is inadequate for long-term bone regeneration. Herein, extra manganese (Mn)-doping is utilized for enhancing the osteogenic ability by mediating adaptive immunity. Intriguingly, Mn-doping engenders heightened recruitment of CD4+ T cells to the bone defect site, concurrently manifesting escalated T helper (Th) 2 polarization and an abatement in Th1 cell polarization. This consequential immune milieu yields a collaborative elevation of interleukin 4, secreted by Th2 cells, coupled with attenuated interferon gamma, secreted by Th1 cells. This orchestrated interplay distinctly fosters the osteogenesis of bone marrow stromal cells and effectuates consequential regeneration of the mandibular bone defect. The modulatory mechanism of Th1/Th2 balance lies primarily in the indispensable role of manganese superoxide dismutase (MnSOD) and the phosphorylation of adenosine 5'-monophosphate-activated protein kinase (AMPK). In conclusion, this study highlights the transformative potential of Mn-doping in amplifying the osteogenic efficacy of silicon-hydroxyapatite nanowires by regulating T cell-mediated adaptive immunity via the MnSOD/AMPK pathway, thereby creating an anti-inflammatory milieu favorable for bone regeneration.

Titanium particles in peri-implantitis: distribution, pathogenesis and prospects

Peri-implantitis is one of the most important biological complications in the field of oral implantology. Identifying the causative factors of peri-implant inflammation and osteolysis is crucial for the disease's prevention and treatment. The underlying risk factors and detailed pathogenesis of peri-implantitis remain to be elucidated. Titanium-based implants as the most widely used implant inevitably release titanium particles into the surrounding tissue. Notably, the concentration of titanium particles increases significantly at peri-implantitis sites, suggesting titanium particles as a potential risk factor for the condition. Previous studies have indicated that titanium particles can induce peripheral osteolysis and foster the development of aseptic osteoarthritis in orthopedic joint replacement. However, it remains unconfirmed whether this phenomenon also triggers inflammation and bone resorption in peri-implant tissues. This review summarizes the distribution of titanium particles around the implant, the potential roles in peri-implantitis and the prevalent prevention strategies, which expects to provide new directions for the study of the pathogenesis and treatment of peri-implantitis.

Emerging Applications of Nanotechnology in Dentistry

Dentistry is a branch of healthcare where nanobiotechnology is reverberating in multiple ways to produce beneficial outcomes. The purpose of this review is to bring into the awareness of the readers the various practical dimensions of the nano-dental complex (nanodentistry) in healthcare and how novelties linked with the field are revolutionizing dentistry. A methodological approach was adopted to collect the latest data on nanotechnology and dentistry from sources, including PubMed, Google Scholar, Scopus, and official websites like the WHO. Nanodentistry is an emerging field in dentistry that involves the use of nanomaterials, nanorobots, and nanotechnology to diagnose, treat, and prevent dental diseases. The results summarize the descriptive analyses of the uses of nanodentistry within orthodontics, preventive dentistry, prosthodontics, restorative dentistry, periodontics, dental surgeries, dental restoration technologies, and other areas of dentistry. The future directions of nano-industries and nano-healthcare have been included to link them with the oral healthcare sector, treatment plans, and improved medical services which could be explored in the future for advanced healthcare regulation. The major limitations to the use of dental nanoproducts are their cost-effectiveness and accessibility, especially in financially constrained countries. These data will help the readers to experience a detailed analysis and comprehensive covering of the diverse achievements of nanodentistry with past analyses, present scenarios, and future implications.

Profiling to Probing: Atomic force microscopy to characterize nano-engineered implants

Surface modification of implants in the nanoscale or implant nano-engineering has been recognized as a strategy for augmenting implant bioactivity and achieving long-term implant success. Characterizing and optimizing implant characteristics is crucial to achieving desirable effects post-implantation. Modified implant enables tailored, guided and accelerated tissue integration; however, our understanding is limited to multicellular (bulk) interactions. Finding the nanoscale forces experienced by a single cell on nano-engineered implants will aid in predicting implants' bioactivity and engineering the next generation of bioactive implants. Atomic force microscope (AFM) is a unique tool that enables surface characterization and understanding of the interactions between implant surface and biological tissues. The characterization of surface topography using AFM to gauge nano-engineered implants' characteristics (topographical, mechanical, chemical, electrical and magnetic) and bioactivity (adhesion of cells) is presented. A special focus of the review is to discuss the use of single-cell force spectroscopy (SCFS) employing AFM to investigate the minute forces involved with the adhesion of a single cell (resident tissue cell or bacterium) to the surface of nano-engineered implants. Finally, the research gaps and future perspectives relating to AFM-characterized current and emerging nano-engineered implants are discussed towards achieving desirable bioactivity performances. This review highlights the use of advanced AFM-based characterization of nano-engineered implant surfaces via profiling (investigating implant topography) or probing (using a single cell as a probe to study precise adhesive forces with the implant surface). STATEMENT OF SIGNIFICANCE: Nano-engineering is emerging as a surface modification platform for implants to augment their bioactivity and achieve favourable treatment outcomes. In this extensive review, we closely examine the use of Atomic Force Microscopy (AFM) to characterize the properties of nano-engineered implant surfaces (topography, mechanical, chemical, electrical and magnetic). Next, we discuss Single-Cell Force Spectroscopy (SCFS) via AFM towards precise force quantification encompassing a single cell's interaction with the implant surface. This interdisciplinary review will appeal to researchers from the broader scientific community interested in implants and cell adhesion to implants and provide an improved understanding of the surface characterization of nano-engineered implants.

Layered Double Hydroxides: A Novel Promising 2D Nanomaterial for Bone Diseases Treatment

Bone diseases including bone defects, bone infections, osteoarthritis, and bone tumors seriously affect life quality of the patient and bring serious economic burdens to social health management, for which the current clinical treatments bear dissatisfactory therapeutic effects. Biomaterial-based strategies have been widely applied in the treatment of orthopedic diseases but are still plagued by deficient bioreactivity. With the development of nanotechnology, layered double hydroxides (LDHs) with adjustable metal ion composition and alterable interlayer structure possessing charming physicochemical characteristics, versatile bioactive properties, and excellent drug loading and delivery capabilities arise widespread attention and have achieved considerable achievements for bone disease treatment in the last decade. However, to the authors' best knowledge, no review has comprehensively summarized the advances of LDHs in treating bone disease so far. Herein, the advantages of LDHs for orthopedic disorders treatment are outlined and the corresponding state-of-the-art achievements are summarized for the first time. The potential of LDHs-based nanocomposites for extended therapeutics for bone diseases is highlighted and perspectives for LDHs-based scaffold design are proposed for facilitated clinical translation.