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

Carbon-based nanomaterials with higher specific surface area: more expensive but more effective antimicrobials

Titanium dental implants are prone to infections by pathogenic bacteria, leading to the formation of biofilm and development of peri-implantitis. Due to their excellent biocompatibility, peroxidase-like activity, and photothermal capabilities, carbon-based nanozymes emerge as a low-risk alternative to traditional antibiotics to treat drug-resistant bacterial infections. However, a crucial question regarding carbon-based nanomaterials with antibacterial properties lies in how to optimize the process parameters to maximize their bactericidal efficacy while minimizing adverse effects such as energy consumption, cytotoxicity, and damage to titanium implants. We have synthesized five groups of carbon-based nanozymes with distinct microstructures through pyrolysis and comprehensively evaluated their performance in five key aspects: energy consumption, photothermal performance, peroxidase-like activity, environmental sensitivity, and cytotoxicity. The results of our experiments provide valuable references for the rational design of carbon-based nanozymes for the treatment of peri-implantitis.

Pinosylvin Inhibits Inflammatory and Osteoclastogenesis via NLRP3 Inflammasome

Pro-inflammatory cytokines such as TNF, IL-1, and IL-6 trigger aberrant osteoclastogenesis and result in massive bone loss. During RANKL-induced osteoclastogenesis, pyroptosis of macrophages/preosteoclasts acts as a pivotal mechanism for IL-1β release, thereby promoting osteoclast maturation and bone resorption. In the current study, it is observed that Pinosylvin (PIN), a compound extracted from European red pine, selectively inhibits LPS- and RANKL-induced release of IL-1β effectively reducing osteoclastogenesis. Notably, PIN inhibits the assembly of NLRP3 and the cleavage of GSDMD, pro-IL-1β, and pro-caspase-1, suggesting its therapeutic effects are NLRP3-targeted. Mechanistically, PIN blockes the NEK7/NLRP3 interaction, but not the NLRP3/ASC interaction, through its 3,5-dihydroxy groups by binding to NEK7, thereby inhibiting subsequent pyroptosis and osteoclastogenesis. Importantly, PIN alleviates inflammatory bone loss due to estrogen deficiency, reduces cranial bone destruction from local LPS injections, and improves survival in LPS-induced septic mice. This study uncovers the specific mechanism behind PIN's potent anti-inflammatory effects and identifies a new therapeutic target for NLRP3-driven diseases.

In Situ Eradication of Mature Oral Biofilm on Titanium Implant Surfaces Using Cold Atmospheric Plasma

Objective: This study evaluated the effectiveness of a new cold atmospheric plasma device (AmbiJet) for eradicating mature oral biofilm on titanium implant surfaces, aiming to improve decontamination methods for the treatment of peri-implant infections. Material and methods: Mature oral biofilms were grown on titanium disks placed in participants' mouths. These disks were divided into control and plasma treatment groups. The AmbiJet device delivered plasma directly to the implant surface for 3 min per 20 mm2, utilizing the applicator nozzle and implant as electrodes. Biofilm reduction was quantified by counting colony-forming units (CFUs). Results: Cold plasma treatment rendered approximately 90% of samples bacteria-free. A > 6-log10 reduction (≈99.9999%) in bacterial load was achieved in 30% of samples, with an overall average reduction of 4.9-log10 across all treated samples. The temperature during treatment remained below 40 °C. Conclusions: Within the study's limitations, cold atmospheric plasma effectively eradicates mature oral biofilm on titanium surfaces. This high disinfection efficacy is likely due to the combined action of reactive species and electrical phenomena, which does not cause significant temperature increases.

Microbial Dysbiosis, Titanium Release, and Peri-implantitis

The peri-implant mucosal barrier is a unique microenvironment where host-microbiome interactions take place on the surface of an implanted biomaterial. Therefore, peri-implant immunity not only is quintessential to oral health but also contributes to the maintenance of the biomaterial-tissue equilibrium in health. This review delves into the intricate interplay between host factors, biomaterial properties, and the microbiome with a focus on the mechanisms underlying peri-implant dysbiosis. Investigations into this complex milieu have led to the emerging understanding of titanium particles released from the implant as significant exposomes. When biomaterial breakdown occurs, implant degradation products form particles that are released in the peri-implant crevice, exerting profound effects on the local immune surveillance. Comparative analyses with natural dentition highlight the distinct immune responses elicited by titanium particles, thereby implicating them as a key modulator of peri-implant dysbiosis that differentiates peri-implant from periodontal inflammation. Nonetheless, disruptions in the homeostatic balance of host-biomaterial interactions are linked to pathogenic shifts of the peri-implant microbiome that are correlated with titanium particles in humans. Collectively, it is now well established that to elucidate the mechanisms governing peri-implant dysbiosis, this triangle of host-microbiome-biomaterial has to be conjointly investigated. This review highlights findings from studies that have underscored the multifaceted nature of peri-implant dysbiosis, emphasizing the intricate crosstalk between host immunity, biomaterial characteristics, and microbial ecology. These findings suggest that the titanium particle exposome may alter key inflammatory cascades in the peri-implant tissues including toll-like receptor activation and inflammasome and complement signaling, which lead to nonresolving destructive inflammation. The presence of abiotic danger signals in the form of implant degradation products in peri-implant tissues may make antimicrobial monotherapies largely ineffective for managing peri-implantitis. In turn, the future of peri-implantitis therapy seems to lie in the development of targeted host modulatory interventions against titanium-mediated inflammatory pathways.

Impact of different chemical debridement agents on early cellular responses to titanium dental implants: A transcriptome-based in vitro study on peri-implant tissue regeneration

BACKGROUND

Poor peri-implant health leads to biofilm accumulation, peri-implantitis, and bone loss. Chemical debridement may help maintain peri-implant health, but its effects on peri-implant cells remain unclear.

METHODS

Five cleaning agents-hydrogen peroxide (H2O2), Poloxamer, H2O2 +Poloxamer, Perisolv, and Paroex-were applied on titanium (Ti) surfaces. Mouse pre-osteoblasts (MC3T3-E1), human gingival fibroblasts (HGF), and human bone marrow stromal cells (hBMSC) were cultured on agent-treated Ti surfaces for up to 120 minutes to assess morphology, cytotoxicity, adhesion, and proliferation. RNA sequencing was performed on hBMSC.

RESULTS

Except for Poloxamer, all treatments inhibited cellular spreading. Paroex increased cytotoxicity and inhibited proliferation. Perisolv impaired hBMSC adhesion and variably affected proliferation. H2O2, alone or with Poloxamer, elevated cytotoxicity and inhibited adhesion in hBMSCs but not MC3T3-E1 or HGF. In contrast, Poloxamer-treated Ti surfaces enhanced adhesion and proliferation across all cell types. RNA sequencing revealed that oxidant-based treatments (H2O2, H2O2 +Poloxamer, Perisolv) suppressed key genes for proliferation (HMGA2, JAG1, NOTCH1, YAP1, TBX3), anti-apoptosis (MCL1, BCL2L2), and adhesion (ITGA2, ITGB3, SPP1), while inhibiting MAPK, PI3K-Akt, and pluripotency pathways.

CONCLUSION

Commercial agents like Perisolv and Paroex impair hBMSC function, with Paroex demonstrating significant cytotoxicity. H2O2 exhibits toxicity, particularly to hBMSCs. Poloxamer improves cell attachment and growth. Given these findings, careful selection of debridement agents is critical to balance cleaning efficacy and cytocompatibility. The adverse effects on hBMSCs necessitate prompt removal postapplication. Further research on biomaterials supporting tissue regeneration postdebridement is needed to restore peri-implant health.

Dysregulation of the Immune System in Advanced Periimplantitis: Systemic Implications and Inflammatory Mechanisms-A Hematological and Immunological Study

Objectives: This study aimed to assess the systemic and local inflammatory responses in patients with periimplantitis, focusing on key immune markers and clinical parameters. The study further explores the relationship between inflammatory markers, clinical indices, and immune dysregulation, particularly regarding T-cell exhaustion and systemic inflammation. Methods: A cohort of patients with periimplantitis, classified into moderate and advanced stages, was compared to a control group of healthy individuals with dental implants. Clinical parameters, including plaque index (API), bleeding on probing (BoP), probing pocket depth (PPD), and peri-implant sulcus depth (PSI), were recorded. Hematological, immunological, and biochemical analyses were performed, with a focus on immune cell populations (NK cells, T-cells, and their exhaustion markers PD-1 and PD-L1). Results: Patients with periimplantitis exhibited significantly higher clinical indices (API, BoP, PSI, and PPD) than the control group, with the most pronounced differences in the advanced periimplantitis group. Hematological analysis revealed increased leukocyte and neutrophil counts, whereas NK cell levels were significantly reduced. Immunological profiling indicated elevated PD-1 and PD-L1 expression on T-cells, suggesting T-cell exhaustion and immune dysregulation. Furthermore, strong correlations were found between increased PPD values and elevated inflammatory marker levels, highlighting the relationship between peri-implant pocket depth and systemic inflammation. Conclusions: The findings confirm that immune dysregulation plays a central role in periimplantitis progression. The association between increased inflammatory markers, immune alterations, and clinical indices emphasizes the need for a multifactorial diagnostic and treatment approach. Integrating immune modulation strategies, clinical assessments, and lifestyle modifications, such as improved oral hygiene and smoking cessation, could improve disease management and reduce recurrence.

Effect of mechanical instrumentation on titanium implant surface properties

OBJECTIVE

To assess the impact of mechanical decontamination using rotary brushes on the surface topography, elemental composition, roughness, and wettability of titanium implant surfaces.

METHODS

Four commercially available rotary brushes were used: Labrida BioClean Brush® (LB), i-Brush1 (IB), NiTiBrush Nano (NiTiB), and Peri-implantitis Brush (PIB). Seventy-five titanium discs with sandblasted, large-grit, acid-etched (SLA) surfaces were randomly assigned to five groups (n = 15): LB, IB, NiTiB, PIB, and a control group. Each disc was treated for 60 seconds with the respective rotary brush according to the manufacturer's instructions. Surface morphology was analysed using Scanning Electron Microscopy (SEM), surface elemental composition with Energy Dispersive X-ray (EDX), surface roughness via optical profilometry, and wettability with a droplet shape analyser.

RESULTS

SEI analysis revealed morphological changes, including scratches, flattening, and loose titanium particles in the IB, PIB, and NiTiB groups, whereas the LB group preserved the original surface morphology. SEM-EDX analysis showed that LB, PIB, and NiTiB groups closely match the control elemental composition. However, IB groups showed significantly different composition. Surface roughness values in the IB, PIB, and NiTiB groups differed significantly from the control (p < 0.05), whereas the LB group had comparable roughness values (p > 0.05). Contact angle measurements indicated enhanced wettability in IB, PIB, and NiTiB groups (p < 0.05), while the LB group exhibited values comparable to the control (p > 0.05).

SIGNIFICANCE

Mechanical decontamination of implant surfaces utilising rotary brushes can alter implant surface properties.

Zinc-Doped Antibacterial Coating as a Single Approach to Unlock Multifunctional and Highly Resistant Titanium Implant Surfaces

Failures of dental and orthopedic implants due to microbial colonization, corrosion, and insufficient osseointegration remain persistent clinical challenges. Current implant surface coatings often lack the mechanical robustness needed for long-term success. Therefore, this study developed zinc (Zn)-doped coatings on titanium implants via plasma electrolytic oxidation (PEO), achieving 11 at % Zn incorporation primarily as zinc oxide (ZnO). The Zn-doped coatings were primarily composed of zinc, calcium, phosphorus, and oxygen, displaying moderate roughness (∼1 μm), hydrophilic behavior, and high crystallinity with anatase and rutile phases. Tribological tests demonstrated over a 50% reduction in mass loss, while electrochemical tests confirmed significantly enhanced corrosion resistance of Zn-doped coating with higher open circuit potential values, larger Nyquist plot semicircles, and higher impedance values at low frequencies compared to controls (p < 0.05). The Zn-doped coatings also showed superior antimicrobial efficacy, reducing Streptococcus sanguinis viability, completely inhibiting Escherichia coli growth, and reducing biofilm biomass by over 60%, which may be related to the sustained Zn release (∼6 μg/cm2) over 7 days. Enhanced bioactivity was evidenced by greater protein adsorption, increased hydroxyapatite formation, and improved preosteoblastic cell metabolism and morphology. Ex vivo analyses confirmed coating mechanical stability, without morphological or chemical impairment, during implant insertion and removal from bovine rib bone, with increased implant stability quotient (ISQ) values, indicating benefits in poor bone quality. These findings highlight the significant promise of Zn-doped plasma electrolytic oxidation coatings for advancing dental and orthopedic implant technology, offering enhanced longevity, antimicrobial defense, and improved bioactivity to optimize clinical outcomes.

Impact of Titanium Plate Fixation on Diacylglycerol and Growth Factor Levels in the Periosteum of the Mandible and Maxilla in Patients with Dentofacial Deformities After Jaw Osteotomies

Titanium is widely recognized for its biocompatibility and utility in maxillofacial and orthopedic surgery; however, its influence on bone remodeling biomarkers remains underexplored. This study investigates the effects of uncoated titanium plates on both the growth factors and diacylglycerols (DAGs) in the periostea of the maxilla and mandible, as DAG signaling is an essential secondary messenger molecule involved in intracellular signaling connected to various growth factors. The study group comprised 20 patients undergoing bimaxillary osteotomies using miniplates and screws made of Ti6Al4V titanium, from whom bone fixations were removed, while the control group included 20 patients operated on for dentofacial deformities (before the insertion of titanium fixations). Diacylglycerol levels in the serum and periosteum were analyzed using tandem mass spectrometry coupled with ultra-high performance liquid chromatography. Growth factors in the periosteum were measured via ELISA with commercially available assay kits. Our findings demonstrate a significant reduction in growth factors, including IGF-1, PDGF, and FGF-23, alongside decreased total DAG levels, suggesting titanium plate stabilization may modulate bone remodeling dynamics. Notably, while overall DAG levels declined, specific DAG species such as C16:0/16:0 and C18:0/18:0 were elevated, whereas polyunsaturated DAGs showed reductions, indicating selective regulation of lipid signaling pathways. Correlation analyses highlighted complex interactions between growth factors and DAGs, with distinct regional differences observed in the mandibular and maxillary periostea. These alterations may result from chronic titanium exposure, potentially inducing a low-grade immune response or modifying the local biochemical environment. This study emphasizes the need for further research into the long-term effects of titanium implants, particularly their influence on lipid metabolism, growth factor dynamics, and bone healing.

Transcriptional modulation of Porphyromonas gingivalis biofilms on titanium-copper implant surfaces

The healthcare sector is currently concerned about infections caused by Porphyromonas gingivalis biofilms due to their high frequency and incidence, particularly in patients with implanted medical devices. This study investigated biofilm formation and biofilm-related gene expression in P. gingivalis on titanium-copper discs and polycarbonate discs. P. gingivalis highly expressed biofilm-related genes were examined using quantitative real-time PCR during biofilm formation on the Ti-Cu surface. SEM analysis revealed various cellular components around the aggregated cells at various stages of biofilm formation. The Ti-Cu surface was colonized by P. gingivalis, as evidenced by biofilm formation levels that varied from ~ 103-104 CFU/cm2 after 2 days of incubation to ~ 105-107 CFU/cm2 after 7 days. Real-time expression analysis showed a significant increase in the expression of signaling molecules on Ti-Cu discs. Furthermore, genes linked to virulence (rgpA, rgpB, and Kgp, fimC, PorK, and PorP) and adhesion (mfa1, fimD, fimA, RpoN, rgpA, rgpBiKgp) demonstrate transcriptional alterations in signaling pathways impacting P. gingivalis biofilm on Ti-Cu surfaces. Scanning electron microscopy (SEM) and confocal microscopy correlated the results of the structural analysis with the expression from the qPCR data. This study adds significant value by advancing the understanding of biofilm formation on Ti-Cu implants.

Predicting interactome networks of up/down regulated proteins and drug-gene interaction analysis associated with peri-implantitis

Background

Peri-implantitis is implant-associated inflammation that leads to irreversible loss of surrounding bone. Early diagnosis increases the success of peri-implantitis treatment. Despite various studies associated with this most common complication, early detection of the onset of peri-implantitis remains a major challenge. Molecular biomarkers are applicable detectors for the early detection of numerous diseases and monitoring their development. The present study aimed to predict interactome networks of up/down regulated proteins and analyze drug-gene interaction in peri-implantitis to identify the diagnostic and druggable genes.

Materials and Methods

In this in silico study, a suitable gene expression profile related to peri-implantitis was retrieved from Gene Expression Omnibus. Screening differentially expressed genes (DEGs) was carried out based on the cut-off criteria |log2 (fold change)|>2 and P < 0.05. Interactome networks were constructed and analyzed by the STRING database (Version: 12.0) and the Cytoscape software (version: 3.9.1). Finally, to investigate drug-gene interaction, detected hub genes were analyzed by DGIdb (version: 5.0.6).

Results

A total of 216 genes were identified as DEGs (129 down-regulated and 87 up-regulated genes) in peri-implantitis. Regarding Cytoscape analysis, FCGR3B, CSF3R, AQP9, TREM1, and P2RY13 were the top 5 hub nodes of up-regulated DEGs, and CXCL10, OASL, IFIT1, RSAD2, and ISG15 were the top 5 hub nodes of down-regulated DEGs. Among these key nods, AQP9, CSF3R, CXCL10, IFIT1, ISG15, OASL, and, FCGR3B were therapeutic targets and had approved drugs.

Conclusion

In this research, seven genes have been identified as druggable genes in peri-implantitis which can be used to treat and diagnose this disease. However, these results and identified genes need to be validated by clinical or experimental methods.

Study of an arginine- and tryptophan-rich antimicrobial peptide in peri-implantitis

The combination of hydrophilic arginine residues and hydrophobic tryptophan residues is considered to be the first choice for designing short-chain antimicrobial peptides (AMPs) due to their potent antibacterial activity. Based on this, we designed an arginine- and tryptophan-rich short peptide, VR-12. Peri-implantitis is a significant microbial inflammatory disorder characterized by the inflammation of the soft tissues surrounding an implant, which ultimately leads to the progressive resorption of the alveolar bone. This study found through antibacterial experiments, wound healing promotion experiments, and anti-inflammatory experiments that VR-12 inhibited and killed planktonic peri-implantitis-associated bacteria, inhibited biofilm formation, and disrupted mature biofilms. Additionally, VR-12 exhibited good biocompatibility with RAW264.7 cells and human gingival fibroblasts (HGFs) cells, promoting proliferation of both cell types. Moreover, VR-12 induced HGFs migration by promoting expression of migration-related factors, thereby promoting soft tissue healing. VR-12 also acted on lipopolysaccharide (LPS)-induced RAW264.7 cells, exerting excellent anti-inflammatory properties by affecting the secretion/expression of inflammation-related factors/genes. Therefore, VR-12 may be a good option for both warding off and treatmenting peri-implantitis.

Titanium particle-induced inflammasome in human gingival epithelial cells

Background/purpose

Peri-implantitis remains a substantial challenge. This study investigated the effect of titanium particles on human oral epithelial cells, focusing on the nucleotide-binding domain and leucine-rich repeat protein (NLRP) 3 inflammasome.

Materials and methods

The Ca9-22 human gingival epithelial cell line was subjected to incubation with titanium particles. To evaluate cell viability, the MTT assay was employed. Total RNA was extracted, and messenger RNA (mRNA) expressions of COX2, TGF-β1, NLRP1, NLPR3, CASP1, and AIM2 were analyzed. The concentration of interleukin (IL)1β in cell supernatants was quantified through enzyme-linked immunosorbent assay. Intracellular reactive oxygen species (ROS) were visualized using an ROS assay Kit.

Results

Ca9-22 cells treated with titanium particles showed >75% cell viability across all concentrations tested, with consistent results. mRNA expressions of inflammation-related genes (COX2 and TGF-β1) significantly increased in a dose-dependent manner. The mRNA expression of NLRP3 and CASP1, as well as the secretion of IL1β, increased after 6-h incubation with titanium particles. Moreover, the ROS assay results showed increased production of ROS after treatment with titanium particles, whereas NLRP3 expression and IL1β secretion reduced after treatment with N-acetyl-l-cysteine (ROS scavenger).

Conclusion

Our findings indicate that titanium particles possess a distinct ability to trigger the NLRP3 inflammasome, partly by producing ROS.

Multi-Scale Characterisation and Mechanical Adhesion in PVD-Deposited Ca-SZ Coating for Implantable Medical Devices

Oral implantology faces a multitude of technical challenges in light of current clinical experience, underlining the need for innovation in implantable medical devices in both mechanical and biological terms. Objectives: This study explores the influence of the thickness factor of calcium-doped zirconia (Ca-SZ) coatings deposited by PVD on their intrinsic mechanical properties and the determinism of the latter on adhesion to the TA6V alloy substrate after mechanical loading for applications in dental implantology. Methods: Three separate thicknesses of 250 nm, 450 nm and 850 nm were evaluated in terms of mechanical strength, modulus of elasticity and adhesion to the substrate, in accordance with ISO 20502:2005. Results: The results show an increase in apparent modulus of elasticity with thickness, reaching values of around 25.05 GPa and 36.3 GPa, close to the cortical bone for the 250 nm and 450 nm thick coatings, respectively. Adhesion tests show a progressive improvement up to 450 nm, followed by a similar observation at 850 nm, underlining the importance of optimal thickness to balance mechanical protection and biomechanical compatibility. Furthermore, the initial roughness and topography of the substrate were not influenced by the different thicknesses of the Ca-SZ coating. Conclusions: Together, these results reinforce the potential of Ca-SZ coatings to minimise stress shielding in dental implants.

Acetyl-11-keto-β-boswellia acid attenuates Ti particle-induced osteoblastic oxidative stress and osteolysis through the Foxo3 signaling pathway

Oxidative stress injury in osteoblasts is one of the leading causes of periprosthetic osteolysis (PPOL). Acetyl-11-keto-β-boswellia acid (AKBA) has been used as an antioxidant in the treatment of various diseases, but its antioxidant mechanism in osteolysis has yet to be elucidated. In this study, a mouse cranial osteolysis model was constructed, and MC3T3-E1 cells and bone marrow mesenchymal stem cells (BMSCs) were cultured in vitro. Western blotting and immunofluorescence staining revealed that titanium (Ti) particles aggravated osteoblast oxidative stress injury and apoptosis. Ti particles and hydrogen peroxide reduced the osteogenic ability of BMSCs. At a certain concentration, AKBA alleviated the oxidative stress injury of MC3T3-E1 cells induced by Ti particles and enhanced the osteogenic ability of BMSCs, and the expression of Forkhead box O3 (Foxo3) increased with increasing AKBA concentration. To verify the antioxidant mechanism of AKBA, we designed and synthesized Foxo3-targeting siRNAs. We found that after Foxo3 expression was inhibited, the protective effect of AKBA on osteoblasts decreased significantly. Moreover, AKBA treatment suppressed bone mass loss in the skull mediated by Ti particles in mice. Therefore, we suggest that AKBA alleviates the oxidative stress injury in osteoblasts induced by Ti particles, at least in part, by regulating the expression of Foxo3. In this study, the mechanism and biosafety of AKBA in treating PPOL were demonstrated to some extent.

Patient Centricity-An Empirical Research on Titanium Dental Implants and Their Adverse Effects on Health Condition

BACKGROUND/OBJECTIVES

Titanium dental implants are considered to be the most modern and effective solution for replacing lost teeth. These medical devices not only restore the chewing and aesthetic functionality of the smile but also provide a stable support for crowns, bridges or dentures. The aim of this study was to identify the perceptions of patients about titanium dental implants and their effects on the human body.

METHODS

A structural equation model (SEM) was conducted to study how a series of independent variables have the ability to influence the perception and intention of the patients regarding these medical devices. A data analysis was performed using WarpPLS 8.0 software. This research was conducted on a sample of 162 respondents.

RESULTS

The results illustrated that patients' perception of titanium dental implants is explained by 71% of the independent variables analysed, and their intention to have a new implant in the next period is explained by 61%. The proposed econometric model was validated, with seven hypotheses accepted out of nine.

CONCLUSIONS

Although titanium has long been used in implant dentistry, in recent years, experts have identified a number of adverse effects that can arise from its use. This study has added value both at the practical and theoretical level. Perception is influenced by respondents' perceived advantages, by the problems perceived by the respondents regarding titanium dental implants, by the degree of awareness of the risks of titanium dental implants, and by the adverse effects experienced by respondents regarding titanium dental implants.

Role of immune dysregulation in peri-implantitis

Peri-implantitis, a complex condition that can lead to dental implant failure, is characterized by inflammatory destruction resulting from immune dysregulation. Oral microbial dysbiosis and foreign body stimulation are the main factors contributing to such dysregulation, impairing immune cell function and triggering an inflammatory response. Immune dysregulation plays a critical role in the pathophysiology of peri-implantitis, impacting the balance of T cell subsets, the production of inflammatory factors, and immune-related molecular signaling pathways. Understanding the relationship between immune dysregulation and peri-implantitis is crucial for developing targeted strategies for clinical diagnosis and individualized treatment planning. This review explores the similarities and differences in the immune microenvironment of oral bacterial infections and foreign body rejection, analyzes the relevant molecular signaling pathways, and identifies new key targets for developing innovative immunotherapeutic drugs and effective and personalized treatment modalities for peri-implantitis. Additionally, it addresses the challenges and potential directions for translating immunotherapy into clinical practice for peri-implantitis, offering insights that bridge the gaps in current literature and pave the way for future research.

Fretting-corrosion at the Implant-Abutment Interface Simulating Clinically Relevant Conditions

OBJECTIVE

Implant treatment is provided to individuals with normal, idealized masticatory forces and also to patients with parafunctional habits such as grinding, clenching, and bruxing. Dental erosion is a common increasing condition and is reported to affect 32 % of adults, increasing with age. This oral environment is conducive to tribocorrosion and the potential loss of materials from the implant surfaces and interfaces with prosthetic components. Although several fretting-corrosion studies have been reported, until now, no study has simulated clinically relevant micromotion. Therefore, our aim is to investigate fretting-corrosion using our new micro-fretting corrosion system, simulating clinical conditions with 5 µm motion at the implant-abutment interface under various occlusal loads and acidic exposures.

METHODS

We simulated four conditions in an oral environment by varying the contact load (83 N and 233 N) and pH levels (3 and 6.5). The commonly used dental implant material, Grade IV titanium, and abutment material Zirconia (ZrO2)/ Grade IV titanium were selected as testing couple materials. Artificial saliva was employed to represent an oral environment. In addition, a standard tribocorrosion protocol was followed, and the pin was controlled to oscillate on the disk with an amplitude of 5 μm during the mastication stage. After the testing, 3D profilometry and scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS) were utilized to analyze the worn surfaces. Inductively coupled plasma mass spectrometry (ICP-MS) was also used to measure the metal ion release.

RESULTS

Energy ratios were below 0.2, indicating a fretting regime of partial slip for all groups. Open-circuit potential (OCP) and electrochemical impedance spectroscopy (EIS) were analyzed to compare the electrochemical behavior among groups. As a result, corrosive damage was observed to be more in the Ti4- Ti4 groups than in Zr-Ti4 ones, whereas more mechanical damage was found in the Zr-Ti4 groups than in the Ti4-Ti4 groups. Possible mechanisms were proposed in the discussion to explain these findings.

SIGNIFICANCE

The results observed from this study might be helpful to clinicians with implant selection. For example, for patients with bruxism, a titanium implant paired with a titanium abutment may be preferable, while patients with GERD may benefit more from a titanium implant paired with a zirconia abutment.

Porous metal materials for applications in orthopedic field: A review on mechanisms in bone healing

Background

Porous metal materials have been widely studied for applications in orthopedic field, owing to their excellent features and properties in bone healing. Porous metal materials with different compositions, manufacturing methods, and porosities have been developed. Whereas, the systematic mechanisms on how porous metal materials promote bone healing still remain unclear.

Methods

This review is concerned on the porous metal materials from three aspects with accounts of specific mechanisms, inflammatory regulation, angiogenesis and osteogenesis. We place great emphasis on different cells regulated by porous metal materials, including mesenchymal stem cells (MSCs), macrophages, endothelial cells (ECs), etc.

Result

The design of porous metal materials is diversified, with its varying pore sizes, porosity material types, modification methods and coatings help researchers create the most experimentally suitable and clinically effective scaffolds. Related signal pathways presented from different functions showed that porous metal materials could change the behavior of cells and the amount of cytokines, achieving good influence on osteogenesis.

Conclusion

This article summarizes the current progress achieved in the mechanism of porous metal materials promoting bone healing. By modulating the cellular behavior and physiological status of a spectrum of cellular constituents, such as macrophages, osteoblasts, and osteoclasts, porous metal materials are capable of activating different pathways and releasing regulatory factors, thus exerting pivotal influence on improving the bone healing effect.

The translational potential of this article

Porous metal materials play a vital role in the treatment of bone defects. Unfortunately, although an increasing number of studies have been concentrated on the effect of porous metal materials on osteogenesis-related cells, the comprehensive regulation of porous metal materials on the host cell functions during bone regeneration and the related intrinsic mechanisms remain unclear. This review summarizes different design methods for porous metal materials to fabricate the most suitable scaffolds for bone remodeling, and systematically reviews the corresponding mechanisms on inflammation, angiogenesis and osteogenesis of porous metal materials. This review can provide more theoretical framework and innovative optimization for the application of porous metal materials in orthopedics, dentistry, and other areas, thereby advancing their clinical utility and efficacy.

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.

Evaluation of risk factors, clinic pathological aspects and implant characteristics in patients of oral peri-implant malignancies

This study was conducted to carry out retrospective analyses of oral peri-implant malignancy (OPIM) focussing on demographic details, risk factors, habit factors, clinicopathological features and implant features in patient with OPIM. Clinical data and demographic data from 1646 individuals with oral cancer undergoing resection procedures were gathered. Clinical, radiological, histopathological assessments and implant characteristics records of these patients were obtained and assessed. 46 (2.79%) cases were found to diagnose with OPIM. 36 (85.76%) cases of OPIM were found to having implant occlusion with opposing prosthesis. Prosthesis/prosthesis occlusion was observed in 18 (50%) cases, prosthesis/inlay occlusion in 4 (11.12%) cases and prosthesis/prosthesis on implants in 14 (38.88%) cases. The surgical placement of implants and the galvanic currents that flow between prostheses can operate as an irritating or inflammatory cofactor that aids in the development of malignancies.

Dynamic assessment of titanium surface oxides following mechanical damage reveals only partial passivation under inflammatory conditions

Motivated by clinical problems of titanium implant degradation, we developed a workflow that enabled assessment of surface oxide dynamics as a function of clinical interventions and inflammation conditions. We found that mechanical damage led to decrease of stoichiometric TiO2 ratio in the passivation oxide film and further resulted in accelerated degradation under inflammatory anaerobic conditions. This method can be employed for the assessment of surface oxides to monitor implant safety.

Risk factors and prediction model of peri-implantitis in post operative periodontitis patients

OBJECTIVES

To analyze the risk factors for peri-implantitis (PI) in patients with periodontitis after dental implantation and to establish a prediction model.

METHODS

A retrospective analysis was conducted using clinical data from 208 patients with periodontitis who required implant restoration due to tooth loss from various causes. These patients, meeting the indications for dental implantation, were treated at the Third People's Hospital of Shenzhen from January 2019 to December 2023. The dataset was divided into training and validation sets in a 7:3 ratio. Logistic regression was used to identify risk factors for PI in these patients. Significant variables from the regression analysis were incorporated into the prediction model. The model's accuracy was evaluated using Receiver Operating Characteristic (ROC) and calibration curves. A decision curve was also drawn to assess the clinical utility of the model. The model's performance was evaluated using the Area Under the Curve (AUC), accuracy, sensitivity, and specificity.

RESULTS

Among the 208 patients, 68 developed PI, resulting in an incidence rate of 32.69%. Independent risk factors for PI included smoking history, diabetes, irregular periodontal treatment, high alveolar bone resorption, and a high plaque index score (all P < 0.05). Based on these risk factors, a logistic regression model was constructed to predict the occurrence of PI. The AUC of the logistic regression model was 0.911 for the training set and 0.823 for the validation set. The calibration curve indicated that the predicted probabilities closely matched the actual probabilities. The decision curve showed that the threshold probabilities for the training and validation sets were 0.1 to 0.85 and 0.1 to 0.81, respectively, suggesting that the net benefit was maximized within these ranges.

CONCLUSION

Smoking history, diabetes, irregular periodontal treatment, high alveolar bone resorption, and a high plaque index score are significant risk factors for PI in patients with periodontitis. The logistic regression model constructed from these factors effectively predicts the probability of PI, providing a valuable reference for the prevention and management of PI.

Titanium nanoparticles released from orthopedic implants induce muscle fibrosis via activation of SNAI2

Titanium alloys represent the prevailing material employed in orthopedic implants, which are present in millions of patients worldwide. The prolonged presence of these implants in the human body has raised concerns about possible health effects. This study presents a comprehensive analysis of titanium implants and surrounding tissue samples obtained from patients who underwent revision surgery for therapeutic reasons. The surface of the implants exhibited nano-scale corrosion defects, and nanoparticles were deposited in adjacent samples. In addition, muscle in close proximity to the implant showed clear evidence of fibrotic proliferation, with titanium content in the muscle tissue increasing the closer it was to the implant. Transcriptomics analysis revealed SNAI2 upregulation and activation of PI3K/AKT signaling. In vivo rodent and zebrafish models validated that titanium implant or nanoparticles exposure provoked collagen deposition and disorganized muscle structure. Snai2 knockdown significantly reduced implant-associated fibrosis in both rodent and zebrafish models. Cellular experiments demonstrated that titanium dioxide nanoparticles (TiO2 NPs) induced fibrotic gene expression at sub-cytotoxic doses, whereas Snai2 knockdown significantly reduced TiO2 NPs-induced fibrotic gene expression. The in vivo and in vitro experiments collectively demonstrated that Snai2 plays a pivotal role in mediating titanium-induced fibrosis. Overall, these findings indicate a significant release of titanium nanoparticles from the implants into the surrounding tissues, resulting in muscular fibrosis, partially through Snai2-dependent signaling.

Mechanochemically Reprogrammed Tantalum Interfaces Enhance Osseointegration Via Immunomodulation

Bone and tooth defects can considerably affect the quality of life and health of patients, and orthopedic implants remain the primary method of addressing such defects. However, implant materials cannot coordinate with the immune microenvironment because of their biological inertness, which may lead to implant loosening or failure. Motivated by the microstructure of nacre, we engineered a biomimetic micro/nanoscale topography on a tantalum surface using a straightforward method. This comprised an organized array of tantalum nanotubes arranged in a brick wall structure, with epigallocatechin gallate acting as "mortar." The coating improved the corrosion resistance, biocompatibility, and antioxidant properties. In vitro and in vivo evaluations further confirmed that coatings can create a favorable bone immune microenvironment through the synergistic effects of mechanochemistry and enhance bone integration. This research offers a new viewpoint on the creation of sophisticated functional implants, possessing vast potential for use in the regeneration and repair of bone tissue.

Preventing periprosthetic osteolysis in aging populations through lymphatic activation and stem cell-associated secretory phenotype inhibition

With increases in life expectancy, the number of patients requiring joint replacement therapy and experiencing periprosthetic osteolysis, the most common complication leading to implant failure, is growing or underestimated. In this study, we found that osteolysis progression and osteoclast differentiation in the surface of the skull bone of adult mice were accompanied by significant expansion of lymphatic vessels within bones. Using recombinant VEGF-C protein to activate VEGFR3 and promote proliferation of lymphatic vessels in bone, we counteracted excessive differentiation of osteoclasts and osteolysis caused by titanium alloy particles or inflammatory cytokines LPS/TNF-α. However, this effect was not observed in aged mice because adipogenically differentiated mesenchymal stem cells (MSCs) inhibited the response of lymphatic endothelial cells to agonist proteins. The addition of the JAK inhibitor ruxolitinib restored the response of lymphatic vessels to external stimuli in aged mice to protect against osteolysis progression. These findings suggest that inhibiting SASP secretion by adipogenically differentiated MSCs while activating lymphatic vessels in bone offers a new method to prevent periprosthetic osteolysis during joint replacement follow-up.

Microbial corrosion of metallic biomaterials in the oral environment

A wide variety of microorganisms have been closely linked to metal corrosion in the form of adherent surface biofilms. Biofilms allow the development and maintenance of locally corrosive environments and/or permit direct corrosion including pitting corrosion. The presence of numerous genetically distinct microorganisms in the oral environment poses a threat to the integrity and durability of the surface of metallic prostheses and implants used in routine dentistry. However, the association between oral microorganisms and specific corrosion mechanisms is not clear. It is of practical importance to understand how microbial corrosion occurs and the associated risks to metallic materials in the oral environment. This knowledge is also important for researchers and clinicians who are increasingly concerned about the biological activity of the released corrosion products. Accordingly, the main goal was to comprehensively review the current literature regarding oral microbiologically influenced corrosion (MIC) including characteristics of biofilms and of the oral environment, MIC mechanisms, corrosion behavior in the presence of oral microorganisms and potentially mitigating technologies. Findings included that oral MIC has been ascribed mostly to aggressive metabolites secreted during microbial metabolism (metabolite-mediated MIC). However, from a thermodynamic point of view, extracellular electron transfer mechanisms (EET-MIC) through pili or electron transfer compounds cannot be ruled out. Various MIC mitigating methods have been demonstrated to be effective in short term, but long term evaluations are necessary before clinical applications can be considered. Currently most in-vitro studies fail to simulate the complexity of intraoral physiological conditions which may either reduce or exacerbate corrosion risk, which must be addressed in future studies. STATEMENT OF SIGNIFICANCE: A thorough analysis on literature regarding oral MIC (microbiologically influenced corrosion) of biomedical metallic materials has been carried out, including characteristics of oral environment, MIC mechanisms, corrosion behaviors in the presence of typical oral microorganisms and potential mitigating methods (materials design and surface design). There is currently a lack of mechanistic understanding of oral MIC which is very important not only to corrosion researchers but also to dentists and clinicians. This paper discusses the significance of biofilms from a biocorrosion perspective and summarizes several aspects of MIC mechanisms which could be caused by oral microorganisms. Oral MIC has been closely associated with not only the materials research but also the dental/clinical research fields in this work.

Titanium corrosion products from dental implants and their effect on cells and cytokine release: A review

INTRODUCTION

Titanium is considered to be an inert material owing to the ability of the material to form a passive titanium oxide layer. However, once the titanium oxide layer is lost, it can lead to exposure of the underlying titanium substructure and can undergo corrosion.

SUMMARY

The article explores the role of titanium ions and particles from dental implants on cells, cytokine release, and on the systemic redistribution of these particles as well as theories proposed to elucidate the effects of these particles on peri-implant inflammation based on evidence from in-vitro, human, and animal studies. Titanium particles and ions have a pro-inflammatory and cytotoxic effect on cells and promote the release of pro-inflammatory mediators like cytokines. Three theories to explain etiopathogenesis have been proposed, one based on microbial dysbiosis, the second based on titanium particles and ions and the third based on a synergistic effect between microbiome and titanium particles on the host.

CONCLUSION

There is clear evidence from in-vitro and limited human and animal studies that titanium particles released from dental implants have a detrimental effect on cells directly and through the release of pro-inflammatory cytokines. Future clinical and translational studies are required to clarify the role of titanium particles and ions in peri-implant inflammation and the etiopathogenesis of peri-implantitis.

Clinical retrospective analysis of peri-implant oral malignancies

PURPOSE

Complications of implant prostheses have direct correlation with the increased use of implants for dental rehabilitation. In this study, we present cases of peri-implant oral malignancies (PIOM) around dental implants and a retrospective analysis of patients treated for PIOM.

METHODS

The retrospective analysis was performed with patients treated for PIOM at the Department of Oral and Maxillofacial Surgery of the Seoul National University Dental Hospital between 2006 and 2014. The patient records were thoroughly screened for previous medical issues, human papilloma virus infections, and other clinical data with a focus on relevant information such as localization, time from implant insertion to the development of the carcinoma, implant type and prosthetic rehabilitation.

RESULTS

Twenty-one patients were diagnosed with PIOM. The male-to-female ratio was 1.625. The mean age of the patients was 60.42 ± 9.35 years old. Three patients reported ongoing alcohol/tobacco consumption. Five patients had a history of previous oral cancer surgery or exhibited mucosal lesions. The time from implant placement until carcinoma diagnosis was 49.13 ± 33.63 months on average. Most PIOM patients (95.2%) were diagnosed with SCC. All patients had previously been treated for peri-implantitis. In 85.7% of the patients, prostheses were observed on the opposing teeth where PIOM occurred.

CONCLUSION

Based on the review of these cases, it can be deduced that there is a possibility that implant treatment and galvanic currents between prosthesis may constitute an irritant and/or inflammatory cofactor which contributes to the formation and/or development of malignant tumors. Patients at potential risk may benefit from individualized recall intervals and careful evaluations.