Search Results (389)

Background: Dentin disinfection plays an important role in prosthodontics, reducing the microbial load, preventing postoperative complications and enhancing the bond strength. This in vitro study aims to evaluate the antimicrobial efficacy of different dentin disinfection protocols, depending on microorganism type, application time, and dentin depth. Methods: A total of 144 extracted human molars were included in the final analysis. The exposed dentin surfaces were contaminated with methicillin-resistant Staphylococcus aureus (MRSA) or Candida albicans (C. albicans). The specimens were disinfected using 2% chlorhexidine digluconate, 3% hydrogen peroxide, or photodynamic therapy with 1% toluidine blue. Microbial growth at superficial and deep dentin was assessed using semi-quantitative visual colony-density scores, resulting in 288 microbiological measurements. Ordinal generalized estimating equation (GEE) models, accounting for within-tooth correlation, were used to evaluate the factors associated with microbial scores. Results: The results showed statistically significant differences among protocols for MRSA (Wald χ² = 62.98; df = 5; p < 0.001) and for C. albicans (Wald χ² = 18.77; df = 5; p = 0.002). Specifically, 2% CHX applied for 30 s was associated with the greatest reduction in MRSA microbial scores (OR = 0.121; p = 0.009), whereas 3% H₂O₂ applied for 60 s was more effective against C. albicans (OR = 0.054; p < 0.001). PDT showed lower and less consistent antimicrobial effects under the tested parameters. Conclusions: The effectiveness of dentin disinfection depends on the microorganism, application time, and dentin depth. Complete elimination of the microbial load cannot be achieved using the disinfectants investigated. Full article

Background and Clinical Significance: Peri-implantitis is an inflammatory condition associated, among other factors, with biofilm accumulation, affecting peri-implant soft and hard tissues and potentially leading to implant loss. Its treatment remains challenging because no single decontamination or regenerative protocol has demonstrated clear superiority. This case report describes a comprehensive surgical and regenerative approach aimed at preserving an affected implant and restoring peri-implant tissue stability; Case Presentation: A systemically healthy 30-year-old patient presented with peri-implant bone loss around an implant in position 25, restored with a lithium disilicate crown and functioning for three years. Treatment included flap elevation, mechanical debridement and air-polishing of the implant surface, followed by thorough irrigation with sterile saline to remove residual abrasive particles and debris, photodynamic antimicrobial therapy, and laser therapy. Bone regeneration was performed using a bone substitute combined with injectable platelet-rich fibrin to produce sticky bone, which was covered with an advanced platelet-rich fibrin membrane. A provisional crown was placed without occlusal contact. After four months, a definitive crown with a modified emergence profile was delivered to improve hygienic access and reduce biofilm retention. Clinical and radiographic follow-up over five years demonstrated stable peri-implant tissues and maintained bone levels; Conclusions: The combined use of surgical decontamination, PRF-assisted regeneration, sticky bone, and prosthetic modification resulted in stable clinical and radiographic outcomes over five years. Identification and elimination of contributing factors were essential for long-term treatment success. Full article

Background/Objectives: Antimicrobial photodynamic therapy (aPDT) has been proposed as an adjunct to non-surgical periodontal therapy, although its benefits remain debated. This study evaluated the clinical and microbiological effects of aPDT combined with ultrasonic scaling and root planing (US-SRP) compared with US-SRP alone in patients with periodontitis. Methods: In this randomized split-mouth clinical trial, 40 patients with stage II–III periodontitis were included. Two non-adjacent sites with probing pocket depth (PPD) ≥ 5 mm were assigned to either control (US-SRP) or test (aPDT + US-SRP) treatment. Clinical parameters, including PPD, bleeding on probing (BOP), plaque index (PI), gingival recession (REC), and clinical attachment level (CAL), were assessed at baseline and after 90 days. Subgingival plaque samples were analyzed by multiplex PCR for major periodontal pathogens. Results: No statistically significant differences were detected for microbiological outcomes at 90 days between groups. Significant greater variations were observed at T3 in the aPDT group for PPD (p = 0.04), BOP (p = 0.03) and PI (p = 0.005), whereas the control group showed a significant reduction only for PI (p = 0.01). Regarding comparisons of Δ(T0–T3) between the aPDT group and the control group, the paired t-test was significant for PPD, REC and CAL (p < 0.001), with a Cohen’s d_av < 0.5 for all three parameters (small effect sizes). In addition, the aPDT group showed a statistically significant reduction in BOP (p = 0.03 *) from T0 (92%) to T3 (50%). Exploratory analyses confirmed the same trend for BOP reduction in the aPDT group both in smokers and non-smokers. Conclusions: Despite the fact that adjunctive aPDT seems to offer predictable clinical outcomes in terms of PPD and BOP reductions, further larger and stratified studies are needed to verify if this treatment can provide superior benefits compared with conventional non-surgical periodontal therapy. Full article

Background: Rising antifungal and antibiotic resistance among Candida species, Staphylococcus aureus, and Enterococcus faecalis has renewed interest in antimicrobial photodynamic therapy (aPDT) as a resistance-independent strategy. Riboflavin 5′-phosphate is a biocompatible, blue-light-activated photosensitizer, but standardized dosing across fungal and bacterial targets is lacking. Objective: The aim of this study was to systematically optimize pre-irradiation incubation time, photosensitizer volume, irradiation time, and laser power for riboflavin 5′-phosphate aPDT (450 nm diode laser) against C. albicans, C. glabrata, C. krusei, S. aureus, and E. faecalis, and compare species susceptibility under optimized conditions. Methods: ATCC strains were treated with 0.1% riboflavin 5′-phosphate across four groups (photodynamic, photosensitizer-only, laser-only, control) in a staged design optimizing incubation (1–30 min), photosensitizer volume (50–150 µL), irradiation time (10–120 s), and power (50–400 mW). Viable counts (CFU/mL) were quantified. Results: Significant reductions occurred only with combined light-plus-photosensitizer treatment. Optimal parameters were 15 min incubation, 100 µL photosensitizer for Candida spp. (50 µL for bacteria), and 120 s at 400 mW, though C. albicans and C. krusei plateaued by 60 s. Maximum reductions were modest: 53.5% (C. albicans), 46.7% (S. aureus), 37.9% (C. glabrata), 35.9% (C. krusei), and 26.5% (E. faecalis), all below 1 log₁₀. A significant light × photosensitizer interaction, confirming photodynamic specificity, was seen for C. albicans, C. glabrata, and S. aureus, but not C. krusei or E. faecalis. Conclusions: Riboflavin 5′-phosphate aPDT under 450 nm light produces reproducible, dose-dependent, species-specific antimicrobial activity, best suited as an adjunctive rather than stand-alone therapy pending biofilm and in vivo validation. Full article

Background: Antimicrobial resistance represents a growing global health challenge, necessitating the development of effective non-antibiotic antimicrobial approaches. Antimicrobial photodynamic therapy (aPDT) has emerged as a promising localized antimicrobial strategy owing to its broad-spectrum activity, biofilm-targeting capability, and low propensity to induce resistance. However, its clinical translation remains restricted by limited photosensitizer (PS) performance, insufficient light penetration, oxygen dependency, biofilm-associated barriers, and the lack of standardized treatment protocols. Methods: This narrative review summarizes recent strategies developed to enhance the efficacy and translational potential of aPDT, including PS engineering, nanomaterial- and non-nanomaterial-based delivery systems, advanced light-source technologies, hypoxia-modulating approaches, and synergistic therapeutic strategies. In addition, current challenges associated with regulatory approval, manufacturing scalability, treatment standardization, and clinical implementation are discussed. Results: Recent advances have transformed aPDT from a conventional PS–light–oxygen system into a multifunctional antimicrobial platform. Emerging approaches improve bacterial targeting, biofilm penetration, reactive oxygen species generation, oxygen utilization, and therapeutic precision. Nevertheless, many advanced systems remain at the preclinical stage due to complexity, cost, safety concerns, and insufficient clinical validation. Conclusions: aPDT should be considered a targeted therapeutic option for accessible, localized, and biofilm-associated infections rather than a replacement for systemic antimicrobial therapy. Future clinical translation will depend on balancing technological innovation with biosafety, scalability, and protocol standardization. Strategies integrating intelligent PS design, oxygen regulation, and clinically feasible synergistic approaches may provide promising pathways toward the broader application of aPDT in antimicrobial management. Full article

Acinetobacter baumannii, a Gram-negative opportunistic bacterium in the ESKAPE group (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, A. baumannii, Pseudomonas aeruginosa and Enterobacter spp.), has emerged as a leading cause of nosocomial infections worldwide. It is known to possess diverse virulence traits and antimicrobial resistance, making it a critical priority pathogen on the World Health Organization’s 2024 Bacterial Priority Pathogens List. Carbapenem-resistant A. baumannii (CRAB) is currently endemic across several continents, with global carbapenem resistance exceeding 70% in healthcare settings and multidrug-resistant infections being associated with alarming mortality rates. This review comprehensively discusses the molecular underpinnings of A. baumannii pathogenesis and virulence, detailing the array of factors coordinated by complex regulatory networks. The convergence of this pathogen’s virulence and antimicrobial resistance traits, resulting in multidrug resistance, leaves clinicians with only a handful of therapeutic options. The review also discusses upcoming therapeutic strategies, including phage therapy, antimicrobial peptides, monoclonal antibodies, photodynamic therapy, and vaccine candidates in the pipeline. While emerging therapeutics show promise, several challenges remain, and integrated approaches are warranted to efficiently combat A. baumannii’s virulence and resistance armamentarium. Full article

The formation of biofilms on medical devices is a major public health challenge, associated with persistent infections, increased antimicrobial resistance and device failure. Biofilms are structured microbial communities, integrated into an extracellular matrix that they produce, giving them protection against antibiotics and host immune defenses. This review provides a synthesis of the mechanisms of biofilm formation, the molecular basis of their resistance, and current and emerging strategies for their prevention and control. This narrative review summarizes (i) the bacterial composition of device-associated biofilms, (ii) the sequential mechanisms of biofilm formation (initial adhesion, maturation, dispersion), (iii) the molecular and physiological basis of biofilm-mediated antimicrobial resistance, and (iv) prevention and control strategies, with particular emphasis on antibacterial and anti-adhesive coatings for orthopedic and dental implants. Surface engineering (anti-adhesive, antimicrobial, nanostructured and biomimetic coatings), anti-biofilm agents (enzymes, quorum sensing inhibitors, bacteriophages), physical approaches (ultrasound, photodynamic therapy) and combined multimodal strategies emerge as the most promising directions. No single strategy ensures complete prevention or eradication of biofilm-associated infections; multidisciplinary multimodal approaches integrating smart biomaterials, controlled antimicrobial release, and artificial intelligence-assisted surface design represent the most realistic clinical pathway forward. Full article

Photodynamic therapy (PDT) represents a promising non-antibiotic strategy for addressing bacterial and fungal infections, particularly in the context of increasing antimicrobial resistance and biofilm-associated disease. PDT is based on the light-induced activation of photosensitizers, leading to the generation of reactive oxygen species (ROS), including singlet oxygen (¹O₂), which induce oxidative damage to multiple microbial targets. Unlike conventional antimicrobial drugs that often act through specific molecular pathways, antimicrobial PDT produces simultaneous damage to membranes, proteins, nucleic acids, and extracellular biofilm components, thereby reducing the probability of resistance development. This review critically analyzes the cellular, biochemical, and biophysical determinants that govern PDT selectivity toward bacterial and fungal cells in comparison with mammalian host tissues. Particular attention is given to photosensitizer localization, membrane interactions, photobleaching, oxygen dependence, light penetration, and the balance between Type I and Type II photochemical mechanisms. The review provides a comparative overview of major molecular photosensitizer classes, including phenothiazines, porphyrins, chlorins, phthalocyanines, xanthene dyes, natural polyphenols, endogenous compounds, and advanced targeted photosensitizers. In addition, this review distinguishes molecular photosensitizers from nanotechnology-based platforms and delivery systems. Nanoparticles, polymeric carriers, hydrogels, and light-activated coatings are discussed not only as photosensitizer delivery tools, but also as systems that modulate aggregation, improve localization, enhance biofilm penetration, and enable surface-confined ROS generation. ROS are capable of causing phototoxic effects wherever they are located. Unless selectively accumulated by target organisms, there can be systemic phototoxicity. Overall, PDT should be regarded as a modular antimicrobial platform in which photosensitizer chemistry, formulation, light delivery, oxygen availability, and infection biology must be co-optimized. Although further studies are required to address clinical translation, regulatory complexity, material safety, and standardized treatment protocols, PDT offers a scientifically robust and clinically relevant approach that may complement conventional antibacterial and antifungal therapies, especially in localized, biofilm-associated, and device-related infections. Full article

Dental caries remains the most prevalent chronic disease worldwide, yet early enamel lesions are reversible if managed with appropriate remineralizing agents. This narrative review synthesizes current evidence on remineralizing agents, their mechanisms of action, and clinical applications, with a focus on dental materials used in preventive and minimally invasive dentistry. Traditional fluoride-based approaches enhance remineralization through fluorapatite formation; however, their effectiveness is limited when calcium and phosphate bioavailability is insufficient. Biomimetic agents, including casein phosphopeptide–amorphous calcium phosphate (CPP-ACP), bioactive glasses, tricalcium phosphate, and nano-hydroxyapatite, provide these bioavailable ions and demonstrate superior performance under challenging clinical conditions. Emerging therapies such as probiotics, photodynamic therapy, and laser-assisted mineralization show promise but require further clinical validation. Based on the primary mechanism of action, an original classification of remineralizing agents is proposed, grouping them into fluoride-based agents, calcium-phosphate systems, nanotechnology-based systems, biofilm modifiers, biomimetic and emerging systems, and adjunctive antimicrobial therapies. The review concludes that bioavailable calcium represents a critical limiting factor in remineralization under certain conditions, and that combination protocols incorporating multiple remineralizing agents, tailored to individual patient risk profiles, achieve superior outcomes compared to single-agent approaches. Clinicians are encouraged to adopt minimally invasive, patient-tailored remineralization strategies that arrest lesions before cavitation, preserving natural tooth structure and reducing the lifelong restorative burden. Full article

Porphyromonas gingivalis (P. gingivalis) is a primary pathogen in periodontitis, yet its elimination is limited by complex anatomical structures. Photodynamic therapy (PDT) is a promising adjunct, but its antimicrobial efficacy is compromised in the acidic microenvironment induced by P. gingivalis. Given that 2′,4′,5′,7′-tetraiodofluorescein (TIF) exhibits robust and stable photodynamic activity under acidic conditions, this study investigated the antibacterial effect of TIF-mediated PDT (TIF-PDT) against P. gingivalis. P. gingivalis ATCC 33277 was treated with TIF (5, 10, 20, and 40 μM), light (525 nm), or both. Reactive oxygen species (ROS) generation was assessed at pH 4.5 or 7.4. Bacterial viability and membrane integrity were evaluated by colony-forming unit (CFU) assay and LIVE/DEAD staining. CFU assays demonstrated that TIF-PDT groups achieved an approximately 4-log reduction in bacterial viability compared to the DEMI, Light, and TIF groups, with no dark cytotoxicity and light-alone effects. LIVE/DEAD staining revealed bright yellow fluorescence in the TIF-PDT (40 μM), indicating membrane damage and significantly lower survival rates than controls. TIF-PDT at 10, 20, and 40 μM produced ROS under both neutral and acidic conditions, exhibited low dark cytotoxicity, and demonstrated potent antibacterial activity against P. gingivalis in vitro, suggesting its potential as an acid-tolerant photosensitizer for periodontitis adjunctive therapy. Full article

In the present research, a new type of biomimetic material loaded with chlorophyll derivatives (CpDs) for photodynamic therapy based on poly(3-hydroxybutyrate) (PHB) was fabricated by the electrospinning method. Such matrices showed great potential for the advanced delivery of photodynamic therapeutic reagents to targeted regions and options for prolonged local application. The key morphological characteristics of fibrous materials were investigated. It was found that incorporation of CpDs leads to a change in the average fiber diameter from 3.5 µm to 2.1 µm, increasing porosity from 80% to 90% and accompanied by an over 3-fold increased proportion of open pores. Moreover, the CpD application facilitated fine hydrophilicity tuning, allowing an increase of this parameter up to 10% under different conditions, neutralizing the hydrophobic nature of the matrix polymer and photosensitizer. Moreover, changes in physical properties, supramolecular structure, photosensitizing effect, and singlet oxygen generation were investigated. The data obtained show that the proposed materials are great examples of convenient and reliable carriers for advanced PDT. The results obtained demonstrate high antimicrobial activity in the presence of irradiation as well as noticeable efficacy against carcinoma, both light and dark. Full article

Background/Objectives: Metabolic dormancy in biofilms leads to reduced drug efficacy in these communities. Different pharmacokinetics and adverse side effects complicate the simultaneous delivery of multiple drugs at appropriate concentrations to the infection site. This study aimed to develop chitosan-coated mesoporous silica nanoparticles loaded with curcumin and amphotericin B (CS@MSNs-Cur-AmB) and to evaluate their antibiofilm activity combined with antimicrobial photodynamic therapy (PDT) against Streptococcus mutans and Candida albicans dual-species biofilms. Methods: CS@MSNs-Cur-AmB were developed. The structure and morphology of the nanoparticles were evaluated using Fourier transform-infrared spectroscopy (FTIR), zeta potential, field emission scanning electron microscopy (FESEM), and thermogravimetric analysis (TGA). Cytotoxicity toward human gingival fibroblasts was assessed. Colony-forming units per milliliter (CFU/mL) were determined. The metabolic activity of biofilm-forming cells was measured using the tetrazolium (MTT) assay. Results: Physicochemical analyses confirmed the synthesis of CS@MSNs-Cur-AmB, revealing a particle size of 228 nm and thermal stability up to 600 °C. Cytotoxicity assays showed that CS@MSNs-Cur-AmB exhibited good biocompatibility (>90%). CS@MSNs-Cur-AmB improved antimicrobial activity, which was further enhanced by blue light-emitting diode (LED) irradiation. CS@MSNs-Cur-AmB under LED irradiation showed the strongest effect, reducing metabolic activity to 27.74 ± 4.08% (1 W/cm², 1 min), p < 0.001). Conclusions: Formulating two drugs in nanocarrier systems may improve therapeutic efficacy by increasing local concentration and reducing systemic exposure. This offers an effective strategy for combating oral biofilms. Full article

Carbon dots (CDs), including carbon quantum dots (CQDs), are ultra-small carbon-based nanomaterials, typically below 10 nm, with tunable photoluminescence, high aqueous dispersibility, favorable biocompatibility, low toxicity, and abundant surface functional groups. These properties make CDs promising multifunctional platforms for nanomedicine, particularly in bioimaging, biosensing, targeted drug/gene delivery, photodynamic therapy (PDT), photothermal therapy (PTT), antimicrobial treatment, and theranostic applications. This review critically examines recent advances in CD fabrication, including top-down, bottom-up, green biomass-derived, microwave-assisted, hydrothermal, and emerging hybrid strategies, with emphasis on how precursor selection, heteroatom doping, surface passivation, and polymer/ligand functionalization regulate optical performance, biological interaction, and therapeutic efficiency. The review discusses structural classification, including CQDs, graphene quantum dots (GQDs), carbon nanodots, and carbonized polymer dots (CPDs), together with major characterization approaches such as ultraviolet–visible (UV–Vis) spectroscopy, Fourier-transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and high-resolution transmission electron microscopy (HRTEM). Particular attention is given to red/near-infrared (NIR) emission, renal clearance, drug-loading behavior, reactive oxygen species (ROS) generation, toxicity mechanisms, biodistribution, and long-term biosafety. This review also highlights key translational barriers, including batch-to-batch variability, limited standardization, scalable manufacturing, regulatory uncertainty, and incomplete pharmacokinetic evaluation. It considers artificial intelligence (AI) and machine learning (ML) as emerging tools for reproducible CD design. CDs represent versatile and clinically promising nanoplatforms, but their translation requires standardized synthesis, rigorous safety assessment, and application-specific regulatory validation. Full article

Antimicrobial photodynamic therapy is a method that utilizes photodynamic inactivation of microorganisms exposed to a photosensitizer irradiated by a specific wavelength, followed by the formation of reactive oxygen species and subsequent oxidative stress. In contrast to antibiotics, which are generally efficient against specific microorganisms, photodynamic inactivation exhibits efficacy against a wide range of bacteria, representing a promising and non-invasive alternative to treating infections caused by pathogens of different origins. This study compares the antibacterial efficacy of five different photosensitizers, including TMPyP, Protoporphyrin IX, PdTPPS₄, Methylene Blue, and ZnPCS₂, against eight representatives of various pathogens, including Gram-negative bacteria Escherichia coli, Pseudomonas aeruginosa, Gram-positive bacteria Staphylococcus aureus, Staphylococcus epidermidis, Enterococcus faecalis, Enterococcus faecium, MRSA and Bacillus subtilis. An optimal irradiation protocol was developed based on growth curve measurements involving double irradiation. To induce the photodynamic effect, we utilized LED emitters with wavelengths of 414 nm and 660 nm, chosen to align with the photophysical properties of the photosensitizers. Additionally, the research included assessments of the radiation’s phototoxicity and the photosensitizers’ dark toxicity against specific microorganisms. The optical properties of the photosensitizers were analyzed using absorption spectrophotometry. The effectiveness of photodynamic inactivation was assessed by determining the minimum inhibitory and bactericidal concentrations. This study aimed to identify the most suitable photosensitizer for clinical application, considering the toxicity of the photosensitizer, the radiant exposure, and its efficacy in photodynamic inactivation. Full article

Background/Objectives: Klebsiella pneumoniae is a major pathogen involved in both acute and chronic infections, characterized by high incidence and significant clinical severity. Over the past decade, resistance to traditional antimicrobial treatments has risen rapidly, highlighting the urgent need for innovative approaches. Light-based antimicrobial strategies, including antimicrobial photodynamic therapy (aPDT), offer a promising approach for addressing drug-resistant bacteria. Combining two photosensitizers (PSs) with antibiotics synergistically enhances ROS generation and multi-target bacterial damage, achieving superior antimicrobial efficacy at reduced PS, light and antibiotic doses while limiting resistance development. We evaluated the efficacy of aPDT using the photosensitizers (PSs) methylene blue (MB) and Photodithazine (PDZ), either alone or in combination with the antibiotic ciprofloxacin (CIP), gentamicin (GEN), or ceftriaxone (CEF), against K. pneumoniae. Methods: Bacterial suspensions were treated with PDZ (25–200 µg/mL) and/or MB (5–20 µg/mL) in the presence of CIP (0.005–4 µg/mL), GEN (0.5–16 µg/mL), or CEF (0.5–16 µg/mL), followed by irradiation at either 15 J/cm² or 30 J/cm². Bacterial survival was assessed by colony-forming unit (CFU/mL) quantification. Results: The combined application of photosensitizers and antibiotics demonstrated a synergistic bactericidal effect against planktonic K. pneumoniae. The combined use of two PSs with antibiotics markedly reduced the antibiotic dose required to achieve a comparable bactericidal effect. Conclusions: This study highlights the potential of combining aPDT with conventional antibiotics as a promising strategy to combat drug-resistant infections, offering enhanced antimicrobial efficacy while allowing for reduced antibiotic dosages to achieve comparable therapeutic outcomes. Full article