Ceramic conversion treated titanium implant abutments with gold for enhanced antimicrobial activity

INTRODUCTION

Peri-implantitis is an inflammatory process around dental implants that is characterised by bone loss that may jeopardize the long-term survival of osseo integrated dental implants. The aim of this study was to create a surface coating on titanium abutments that possesses cellular adhesion and anti-microbial properties as a post-implant placement strategy for patients at risk of peri-implantitis.

MATERIALS AND METHODSMETHODS

Titanium alloy Grade V stubs were coated with gold particles and then subjected to ceramic conversion treatment (CCT) at 620 °C for 3, 8 and 80 h. The surface characteristics and chemistry were assessed using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD) analysis. The leaching profile was investigated by inductively coupled plasma mass spectroscopy (ICP-MS) for all groups after 7, 14 and 28 days in contact with distilled water. A scratch test was conducted to assess the adhesion of the gold coating to the underlying titanium discs. Two bacterial species (Staphylococcus aureus (SA) & Fusobacterium nucleatum (FN)) were used to assess the antibacterial behaviour of the coated discs using a direct attachment assay test. The potential changes in surface chemistry by the bacterial species were investigated by grazing angle XRD.

RESULTS

The gold pre-coated titanium discs exhibited good stability of the coating especially after immersion in distilled water and after bacterial colonisation as evident by XRD analysis. Good surface adhesion of the coating was demonstrated for gold treated discs after scratch test analysis, especially titanium, following a 3-hour (3 H) ceramic conversion treatment. All coated discs exhibited significantly improved antimicrobial properties against both tested bacterial species compared to untreated titanium discs.

CONCLUSIONS

Ceramic conversion treated titanium with a pre-deposited gold layer showed improved antimicrobial properties against both SA and FN species than untreated Ti-C discs. Scratch test analysis showed good adherence properties of the coated discs the oxide layer formed is firmly adherent to the underlying titanium substrate, suggesting that this approach may have clinical efficacy for coating implant abutments.

Experimental models for peri-implant diseases: a narrative review

OBJECTIVES

Peri-implant diseases, being the most common implant-related complications, significantly impact the normal functioning and longevity of implants. Experimental models play a crucial role in discovering potential therapeutic approaches and elucidating the mechanisms of disease progression in peri-implant diseases. This narrative review comprehensively examines animal models and common modeling methods employed in peri-implant disease research and innovatively summarizes the in vitro models of peri-implant diseases.

MATERIALS AND METHODS

Articles published between 2015 and 2023 were retrieved from PubMed/Medline, Web of Science, and Embase. All studies focusing on experimental models of peri-implant diseases were included and carefully evaluated.

RESULTS

Various experimental models of peri-implantitis have different applications and advantages. The dog model is currently the most widely utilized animal model in peri-implant disease research, while rodent models have unique advantages in gene knockout and systemic disease induction. In vitro models of peri-implant diseases are also continuously evolving to meet different experimental purposes.

CONCLUSIONS

The utilization of experimental models helps simplify experiments, save time and resources, and promote advances in peri-implant disease research. Animal models have been proven valuable in the early stages of drug development, while technological advancements have brought about more predictive and relevant in vitro models.

CLINICAL RELEVANCE

This review provides clear and comprehensive model selection strategies for researchers in the field of peri-implant diseases, thereby enhancing understanding of disease pathogenesis and providing possibilities for developing new treatment strategies.

Advanced Immunomodulatory Biomaterials for Therapeutic Applications

The multifaceted biological defense system modulating complex immune responses against pathogens and foreign materials plays a critical role in tissue homeostasis and disease progression. Recently developed biomaterials that can specifically regulate immune responses, nanoparticles, graphene, and functional hydrogels have contributed to the advancement of tissue engineering as well as disease treatment. The interaction between innate and adaptive immunity, collectively determining immune responses, can be regulated by mechanobiological recognition and adaptation of immune cells to the extracellular microenvironment. Therefore, applying immunomodulation to tissue regeneration and cancer therapy involves manipulating the properties of biomaterials by tailoring their composition in the context of the immune system. This review provides a comprehensive overview of how the physicochemical attributes of biomaterials determine immune responses, focusing on the physical properties that influence innate and adaptive immunity. This review also underscores the critical aspect of biomaterial-based immune engineering for the development of novel therapeutics and emphasizes the importance of understanding the biomaterials-mediated immunological mechanisms and their role in modulating the immune system.

Graphene oxide/ε-poly-L-lysine self-assembled functionalized coatings improve the biocompatibility and antibacterial properties of titanium implants

The construction of an antibacterial biological coating on titanium surface plays an important role in the long-term stability of oral implant restoration. Graphene oxide (GO) has been widely studied because of its excellent antibacterial properties and osteogenic activity. However, striking a balance between its biological toxicity and antibacterial properties remains a significant challenge with GO. ε-poly-L-lysine (PLL) has broad-spectrum antibacterial activity and ultra-high safety performance. Using Layer-by-layer self-assembly technology (LBL), different layers of PLL/GO coatings and GO self-assembly coatings were assembled on the surface of titanium sheet. The materials were characterized using scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and contact angle test. The antibacterial properties of Porphyromonas gingivalis (P.g.) were analyzed through SEM, coated plate experiment, and inhibition zone experiment. CCK-8 was used to determine the cytotoxicity of the material to MC3T3 cells, and zebrafish larvae and embryos were used to determine the developmental toxicity and inflammatory effects of the material. The results show that the combined assembly of 20 layers of GO and PLL exhibits good antibacterial properties and no biological toxicity, suggesting a potential application for a titanium-based implant modification scheme.

Graphene-Based Material-Mediated Immunomodulation in Tissue Engineering and Regeneration: Mechanism and Significance

Tissue engineering and regenerative medicine hold promise for improving or even restoring the function of damaged organs. Graphene-based materials (GBMs) have become a key player in biomaterials applied to tissue engineering and regenerative medicine. A series of cellular and molecular events, which affect the outcome of tissue regeneration, occur after GBMs are implanted into the body. The immunomodulatory function of GBMs is considered to be a key factor influencing tissue regeneration. This review introduces the applications of GBMs in bone, neural, skin, and cardiovascular tissue engineering, emphasizing that the immunomodulatory functions of GBMs significantly improve tissue regeneration. This review focuses on summarizing and discussing the mechanisms by which GBMs mediate the sequential regulation of the innate immune cell inflammatory response. During the process of tissue healing, multiple immune responses, such as the inflammatory response, foreign body reaction, tissue fibrosis, and biodegradation of GBMs, are interrelated and influential. We discuss the regulation of these immune responses by GBMs, as well as the immune cells and related immunomodulatory mechanisms involved. Finally, we summarize the limitations in the immunomodulatory strategies of GBMs and ideas for optimizing GBM applications in tissue engineering. This review demonstrates the significance and related mechanism of the immunomodulatory function of GBM application in tissue engineering; more importantly, it contributes insights into the design of GBMs to enhance wound healing and tissue regeneration in tissue engineering.

Comparison of Prophylactic Effects between Localized Biomimetic Minocycline and Systematic Amoxicillin on Implants Placed Immediately in Infected Sockets

This study evaluated the prophylactic effect of localized biomimetic minocycline and systemic amoxicillin on immediate implant placement at infected extraction sites. Twelve mongrels with six implants each were randomly assigned to five groups: uninfected negative control (Group N); infected with oral complex bacteria (Group P); infected and treated with amoxicillin one hour before implant placement (Group A); infected and treated with minocycline during implant placement (Group B); and infected and treated with amoxicillin one hour before implant placement and with minocycline during implant placement (Group C). Radiographic bone level, gingival index (GI), probing depth (PD), papillary bleeding index (PBI), and removal torque (RT) were recorded. There was no significant difference between Groups A, B, and C for bone loss. Group A showed the highest RT, the lowest PBI, and significantly lower GI and PD values than Group P. Group B exhibited significantly higher RT value than Group N and significantly smaller PD value than Group P at 6 w postoperatively. Localized minocycline could improve implant success by reducing bone loss and increasing RT and systemic amoxicillin could maintain the stability of the peri-implant soft tissue. However, combined use of these two antibiotics did not augment the prophylactic effect.

Can Graphene Pave the Way to Successful Periodontal and Dental Prosthetic Treatments? A Narrative Review

Graphene, as a promising material, holds the potential to significantly enhance the field of dental practices. Incorporating graphene into dental materials imparts enhanced strength and durability, while graphene-based nanocomposites offer the prospect of innovative solutions such as antimicrobial dental implants or scaffolds. Ongoing research into graphene-based dental adhesives and composites also suggests their capacity to improve the quality and reliability of dental restorations. This narrative review aims to provide an up-to-date overview of the application of graphene derivatives in the dental domain, with a particular focus on their application in prosthodontics and periodontics. It is important to acknowledge that further research and development are imperative to fully explore the potential of graphene and ensure its safe use in dental practices.

Graphene and its derivatives: "one stone, three birds" strategy for orthopedic implant-associated infections

Orthopedic implants provide an avascular surface for microbial attachment and biofilm formation, impeding the entry of immune cells and the diffusion of antibiotics. The above is an important cause of dental and orthopedic implant-associated infection (IAI). For the prevention and treatment of IAI, the drawbacks of antibiotic resistance and surgical treatment are increasingly apparent. Due to their outstanding biological properties such as biocompatibility, immunomodulatory effects, and antibacterial properties, graphene-based nanomaterials (GBNs) have been applied to bone tissue engineering to deal with IAI, and in particular have great potential application in drug/gene carriers, multi-functional platforms, and coating forms. Here we review the latest research progress and achievements in GBNs for the prevention and treatment of IAI, mainly including their biomedical applications for antibacterial and immunomodulation effects, and for inducing osteogenesis. Furthermore, the biosafety of graphene family materials in bone tissue regeneration and the feasibility of clinical application are critically analyzed and discussed.

Graphene on dentistry: A bibliometric and scientometric analysis

Background

Today, the development of dental materials is a very important issue. Graphene has been used in dentistry to strengthen many materials.

Aim

The aim of this study was to analyze leading countries and to identify the preferred journals, the most commonly used keywords, and the most productive authors in the field of graphene.

Materials and Methods

The search keyword was "graphene" on the Web of Science database; the search was restricted to before 2022. The selected search from the Web of Science database included the title of articles, authors, year of publication, country, citation count, and keywords. An analysis was performed regarding citations and documents, authors, journals, and keywords using a bibliometric software program. All articles were evaluated and subjected to scientometric analysis.

Results

Twenty six articles were included in the study. There has been a remarkable increase in published articles from past to present, and a regular increase is observed in the number of citations. Dental Materials has highest number of publications among the articles included in the present study. Dr. Rosa, who had the highest number of citations, is also the most effective author. Graphene has many studies in dentistry with different materials. As per the data obtained, graphene, graphene oxide, and peri-implantitis are the most used keywords and Singapore and China are at the forefront of the countries where the articles are published.

Conclusion

This bibliometric analysis reveals the progress and trend of research on graphene in dentistry and extensive collaborations between authors, countries, and institutions. The findings of this study can help inspire researchers to plan new studies and collaborate on graphene.

In Vitro Studies of Graphene for Management of Dental Caries and Periodontal Disease: A Concise Review

Graphene is a single-layer two-dimensional carbon-based nanomaterial. It presents as a thin and strong material that has attracted many researchers’ attention. This study provides a concise review of the potential application of graphene materials in caries and periodontal disease management. Pristine or functionalized graphene and its derivatives exhibit favorable physicochemical, mechanical, and morphological properties applicable to biomedical applications. They can be activated and functionalized with metal and metal nanoparticles, polymers, and other small molecules to exhibit multi-differentiation activities, antimicrobial activities, and biocompatibility. They were investigated in preventive dentistry and regenerative dentistry. Graphene materials such as graphene oxide inhibit cariogenic microbes such as Streptococcus mutans. They also inhibit periodontal pathogens that are responsible for periodontitis and root canal infection. Graphene-fluorine promotes enamel and dentin mineralization. These materials were also broadly studied in regenerative dental research, such as dental hard and soft tissue regeneration, as well as periodontal tissue and bone regeneration. Graphene oxide-based materials, such as graphene oxide-fibroin, were reported as promising in tissue engineering for their biocompatibility, bioactivity, and ability to enhance cell proliferation properties in periodontal ligament stem cells. Laboratory research showed that graphene can be used exclusively or by incorporating it into existing dental materials. The success of laboratory studies can translate the application of graphene into clinical use.

Research on Graphene and Its Derivatives in Oral Disease Treatment

Oral diseases present a global public health problem that imposes heavy financial burdens on individuals and health-care systems. Most oral health conditions can be treated in their early stage. Even if the early symptoms of oral diseases do not seem to cause significant discomfort, prompt treatment is essential for preventing their progression. Biomaterials with superior properties enable dental therapies with applications in restoration, therapeutic drug/protein delivery, and tissue regeneration. Graphene nanomaterials have many unique mechanical and physiochemical properties and can respond to the complex oral microenvironment, which includes oral microbiota colonization and high masticatory force. Research on graphene nanomaterials in dentistry, especially in caries, periodontitis therapy, and implant coatings, is progressing rapidly. Here, we review the development of graphene and its derivatives for dental disease therapy.

Graphene-Based Nanomaterials for Dental Applications: Principles, Current Advances, and Future Outlook

With the development of nanotechnology, nanomaterials have been used in dental fields over the past years. Among them, graphene and its derivatives have attracted great attentions, owing to their excellent physicochemical property, morphology, biocompatibility, multi-differentiation activity, and antimicrobial activity. In our review, we summarized the recent progress about their applications on the dentistry. The synthesis methods, structures, and properties of graphene-based materials are discussed. Then, the dental applications of graphene-based materials are emphatically collected and described. Finally, the challenges and outlooks of graphene-based nanomaterials on the dental applications are discussed in this paper, aiming at inspiring more excellent studies.

Potential of Carbon-Based Nanocomposites for Dental Tissue Engineering and Regeneration

While conventional dental implants focus on mechanical properties, recent advances in functional carbon nanomaterials (CNMs) accelerated the facilitation of functionalities including osteoinduction, osteoconduction, and osseointegration. The surface functionalization with CNMs in dental implants has emerged as a novel strategy for reinforcement and as a bioactive cue due to their potential for mechanical reinforcing, osseointegration, and antimicrobial properties. Numerous developments in the fabrication and biological studies of CNMs have provided various opportunities to expand their application to dental regeneration and restoration. In this review, we discuss the advances in novel dental implants with CNMs in terms of tissue engineering, including material combination, coating strategies, and biofunctionalities. We present a brief overview of recent findings and progression in the research to show the promising aspect of CNMs for dental implant application. In conclusion, it is shown that further development of surface functionalization with CNMs may provide innovative results with clinical potential for improved osseointegration after implantation.

Efficacy of local antibiotic therapy in the treatment of peri-implantitis: A systematic review and meta-analysis

OBJECTIVES

The aim of this systematic review and meta-analysis was to state the efficacy of local administration of antibiotics in the treatment of peri-implantitis in terms of peri-implant probing depth (PPD) and bleeding on probing (BoP) reduction.

DATA, SOURCES AND STUDY SELECTION

Electronic and manual literature searches were conducted. Screening process was done using the National Library of Medicine (MEDLINE by PubMed), Embase and the Cochrane Oral Health. Included articles were randomized controlled trials and observational studies. Weighted means were calculated. Heterogeneity was determined using Higgins (I2). Due to the encountered heterogeneity between the studies being combined, random-effects models were applied in order to analyze effect sizes. Twelve studies (365 patients and 463 implants) were included in the systematic review. After peri-implantitis treatment with local antibiotics, PPD was reduced 1.40 mm (95% confidence interval: 0.82-1.98). When local antibiotics were applied, a 0.30 mm higher reduction of PPD was obtained than in the control group (95% confidence interval: 0.07-0.53). BoP attained an odds ratio value of 1.82 (95% confidence interval: 1.09-3.04), indicating that the likehood of bleeding is almost two-fold when antibiotics are not locally administrated. Adverse effects were not found after applying local antibiotics.

CONCLUSIONS

The local antibiotic administration does reduce, without adverse effects, both peri-implant probing depths and bleeding on probing in patients affected by peri-implantitis, if compared to control groups without local antibiotic application.

CLINICAL SIGNIFICANCE

Patients with dental implants frequently suffer from peri-implantitis. Clinical features of peri-implantitis lesions include the presence of bleeding on probing and increased peri-implant probing depths. Both BoP and PPD have become reduced after local administration of antibiotics.

Methods of Topical Administration of Drugs and Biological Active Substances for Dental Implants-A Narrative Review

Dental implants are, nowadays, established surgical devices for the restoration of lost teeth. Considered as an alternative for traditional prosthetic appliances, dental implants surpass them in reliability and patient feedback. Local drug delivery around the implants promotes osseointegration and reduces peri-implantitis. However, there are currently no methods of a multiple, precise topical administration of drugs to the implant area. Engineering coatings on the implants, drug application on carriers during implantation, or gingival pockets do not meet all requirements of dental surgeons. Therefore, there is a need to create porous implants and other medical devices that will allow a multiple drug delivery at a controlled dose and release profile without traumatic treatment. Due to the growing demand for the use of biologically active agents to support dental implant treatment at its various stages (implant placement, long-term use of dental superstructures, treatment of the peri-implant conditions) and due to the proven effectiveness of the topical application of pharmacological biologically active agents to the implant area, the authors would like to present a review and show the methods and devices that can be used by clinicians for local drug administration to facilitate dental implant treatment. Our review concludes that there is a need for research in the field of inventions such as new medical devices or implants with gradient solid-porous structures. These devices, in the future, will enable to perform repeatable, controllable, atraumatic, and repeatable injections of active factors that may affect the improvement of osteointegration and the longer survival of implants, as well as the treatment of peri-implantitis.

Nerve growth factor-chondroitin sulfate/hydroxyapatite-coating composite implant induces early osseointegration and nerve regeneration of peri-implant tissues in Beagle dogs

Background

Osseointegration is the premise of the chewing function of dental implant. Nerve growth factor (NGF), as a neurotrophic factor, can induce bone healing. However, the influence of NGF-chondroitin sulfate (CS)/hydroxyapatite (HA)-coating composite implant on the osseointegration and innervations is still not entirely clear.

Materials and methods

NGF-CS/HA-coating composite implants were prepared using the modified biomimetic method. The characteristics of NGF-CS/HA-coating implants were determined using a scanning electron microscope. After NGF-CS/HA-coating implants were placed in the mandible of Beagle dogs, the early osseointegration and innervation in peri-implant tissues were assessed through X-ray, Micro-CT, maximal pull-out force, double fluorescence staining, toluidine blue staining, DiI neural tracer, immunohistochemistry, and RT-qPCR assays.

Results

NGF-CS/HA-coating composite implants were made successfully, which presented porous mesh structures with the main components (Ti and HA). Besides, we revealed that implantation of NGF-CS/HA-coating implants significantly changed the morphology of bone tissues and elevated maximum output, MAR, BIC, and nerve fiber in the mandible of Beagle dogs. Moreover, we proved that the implantation of NGF-CS/HA-coating implants also markedly upregulated the levels of NGF, osteogenesis differentiation, and neurogenic differentiation-related genes in the mandible of Beagle dogs.

Conclusion

Implantation of NGF-CS/HA-coating composite implants has significant induction effects on the early osseointegration and nerve regeneration of peri-implant tissues in the mandible of Beagle dogs.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13018-020-02177-5.

Hard tissue volumetric and soft tissue contour linear changes at implants with different surface characteristics after experimentally induced peri-implantitis: an experimental in vivo investigation

OBJECTIVE

To evaluate the hard tissue volumetric and soft tissue contour linear changes in implants with two different implant surface characteristics after a ligature-induced peri-implantitis.

MATERIAL AND METHODS

In eight beagle dogs, implants with the same size and diameter but distinct surface characteristics were placed in the healed mandibular sites. Test implants had an external monolayer of multi-phosphonate molecules (B+), while control implants were identical but without the phosphonate-rich surface. Once the implants were osseointegrated, oral hygiene was interrupted and peri-implantitis was induced by placing subgingival ligatures. After 16 weeks, the ligatures were removed and peri-implantitis progressed spontaneously. Bone to implant contact (BIC) and bone loss (BL) were assessed three-dimensionally with Micro-Ct (μCT). Dental casts were optically scanned and the obtained digitalized standard tessellation language (STL) images were used to assess the soft tissue vertical and horizontal contour linear changes.

RESULTS

Reduction of the three-dimensional BIC percentage during the induction and progression phases of the experimental peri-implantitis was similar for both the experimental and control implants, without statistically significant differences between them. Soft tissue analysis revealed for both implant groups an increase in horizontal dimension after the induction of peri-implantitis, followed by a decrease after the spontaneous progression period. In the vertical dimension, a soft tissue dehiscence was observed in both groups, being more pronounced at the buccal aspect.

CONCLUSIONS

The added phosphonate-rich surface did not provide a more resistant environment against experimental peri-implantitis, when assessed by the changes in bone volume and soft tissue contours.

CLINICAL RELEVANCE

Ligature-induced peri-implantitis is a validated model to study the tissue changes occurring during peri-implantitis. It was hypothesized that a stronger osseointegration mediated by the chemical bond of a phosphonate-rich implant surface would develop an environment more resistant to the inflammatory changes occurring after experimental peri-implantitis. These results, however, indicate that the hard and soft tissue destructive changes occurring at both the induction and progression phases of experimental peri-implantitis were not influenced by the quality of osseointegration.

Synthesis and characterization of graphene oxide-zirconia (GO-ZrO2) and hydroxyapatite-zirconia (HA-ZrO2) nano-fillers for resin-based composites for load-bearing applications

OBJECTIVES

The study aims to synthesize two different types of nano-fillers based on zirconia (ZrO₂), which was functionalized with graphene oxide (GO-ZrO₂), and hydroxyapatite (HA-ZrO₂), and to implement them in an experimental methacrylate matrix containing new dimethacrylic oligomers.

METHODS

Nano-particles were synthesized via a modified Hummer's method and a sol-gel route. Bisphenol A-glycidyl methacrylate oligomers (Bis-GMA_336[0-1]) were synthesized from an epoxy resin that reacted with methacrylic acid in the presence of a basic catalyst. Traditional dental glass-fillers (Barium oxide/BaO and Barium fluoride/BaF₂) were synthesized to create an experimental resin-based composite (RBC) used as reference. Filler morphology was evaluated via Transmission Electron Microscopy. RBCs were characterised by real-time Fourier transform infrared spectroscopy (degree of cure/DC, polymerisation kinetics), real-time spectrometry (light transmittance), 3-point bending test (flexural strength and modulus, Weibull parameters), and depth-sensing indentation test (plastic and elastic deformation parameters).

RESULTS

The synthesized nanohybrid fillers proved good dispersing performance. Mechanical properties and materials' reliability are within or above the mean values reported in the literature for RBCs. Addition of HA-ZrO₂-fillers resulted in a decrease light transmission, DC and mechanical properties. Except for the HA-ZrO₂ RBC, materials showed a high resistance to softening in solvent.

CONCLUSIONS

The synthesis of GO-ZrO₂ and HA-ZrO₂ nanohybrid particles and their implementation in experimental RBCs has proven successful. Adjustments of the light transmission through suitable co-fillers in addition to GO-ZrO₂ as well as adjustments of the amount of HA-ZrO₂ are necessary to enable reduced curing time (<20 s).

CLINICAL SIGNIFICANCE

The addition of nanofillers with tailor-made properties can help improving the performance of modern restoratives.

Ultrasound-assisted synthesis of BiVO4/C-dots/g-C3N4Z-scheme heterojunction photocatalysts for degradation of minocycline hydrochloride and Rhodamine B: optimization and mechanism investigation

BiVO₄/C-Dots/g-C₃N₄Z-scheme photocatalyst with carbon dots as the electron mediators efficiently degrades minocycline hydrochloride and dye wastewater.