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Monitoring of Virulence Factors and Metabolic Activity in Aggregatibacter Actinomycetemcomitans Cells Surviving Antimicrobial Photodynamic Therapy via Nano-Chitosan Encapsulated Indocyanine Green
摘要： Aggregatibacter actinomycetemcomitans is an etiological agent frequently found in both chronic and aggressive periodontitis as well as peri-implantitis. This study assessed the effect of antimicrobial photodynamic therapy (aPDT), as an alternative treatment modality, by nano-chitosan encapsulated indocyanine green (CNPs/ICG), as a photosensitizer, on the virulence features of cell-surviving aPDT against A. actinomycetemcomitans. The cell cytotoxicity effect of CNPs/ICG was evaluated on primary human gingival fibroblast cells. A. actinomycetemcomitans ATCC 33384 photosensitized with CNPs/ICG was irradiated with diode laser at a wavelength of 810 nm for 1 min (31.2 J/cm2), and then bacterial viability measurements were done. The biofilm formation ability, metabolic activity, and antimicrobial susceptibility profiles were assessed for cell-surviving aPDT. The effect of aPDT on the expression of the fieF virulent gene, encoding the ferrous-iron efflux pump, was evaluated by the quantitative real-time PCR. CNPs/ICG-aPDT resulted in a significant reduction of cell viability (91%), biofilm formation capacity (53%), and metabolic activity (48%) of A. actinomycetemcomitans when compared to the control group (P < 0.05). Moreover, fieF gene expression was downregulated by 14.8 folds after the strains were treated with aPDT. The virulence of A. actinomycetemcomitans strain reduced in cells surviving aPDT with CNPs/ICG, indicating the potential implications of aPDT for the treatment of A. actinomycetemcomitans infections in periodontitis and peri-implantitis in vivo.
关键词： peri-implantitis,nano-chitosan,Aggregatibacter actinomycetemcomitans,antimicrobial photodynamic therapy,indocyanine green,periodontitis
更新于2025-09-23 15:21:01
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Photoexcitation triggering via semiconductor Graphene Quantum Dots by photochemical doping with Curcumin versus perio-pathogens mixed biofilms
摘要： Background: Recently, antimicrobial photodynamic therapy (aPDT) as an alternative treatment modality has been used adjunctively in the treatment of periodontitis and peri-implantitis. Photosensitizing agents in the form of nanoparticles have been designed for improving the e?ciency of aPTD. Graphene quantum dots are a special type of nanocrystals that can promote aPDT when coupled with curcumin (Cur). The main objective of the present study was to investigate the e?ects of photoexcited GQD-Cur on the metabolic activity of perio-pathogen mixed bio?lms. Materials and methods: GQD-Cur was synthesized and characterized by scanning electron microscopy (SEM), dynamic light scattering (DLS), fourier transform infrared (FTIR) spectroscopy, ultraviolet-visible spectrometry (UV–Vis), and X-ray di?raction (XRD). The cell cytotoxicity e?ect of GQD-Cur was evaluated on primary human gingival ?broblast (HuGu) cells. Perio-pathogen mixed bio?lms including Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, and Prevotella intermedia photosensitized with GQD doped with Cur were irradiated with a blue LED at a wavelength of 435 ± 20 nm for 1 min, and then bacterial viability measurements were performed. The antimicrobial susceptibility pro?le, bio?lm formation ability, amount of reactive oxygen species (ROS) released, and variations of gene expressions involved in bio?lm formation were assessed. Results: The SEM, DLS, FTIR, UV–Vis spectrometry, and XRD pattern con?rmed that GQD-Cur was synthesized successfully. According to the results, GQD-Cur exhibited no cytotoxicity against HuGu cells. Photoexcited GQD-Cur resulted in a signi?cant reduction in cell viability (93%) and bio?lm formation capacity (76%) of peri-pathogens compared to the control group (P < 0.05). According to the results, a signi?cant concentration-dependent increase in the ROS generation was observed in perio-pathogens mixed cells treated with di?erent doses of GQD-Cur-aPDT. Moreover, rcpA, ?mA, and inpA gene expression pro?les were downregulated by 8.1-, 9.6-, and 11.8-folds, respectively. Conclusions: Based on the results, photoexcited GQD-Cur have a high potency of perio-pathogens suppression in planktonic and bio?lm forms and downregulation of the bio?lm genes expression pattern was exploited as a nanoscale-based platform for periodontitis.
关键词： Curcumin,Antimicrobial photodynamic therapy,Graphene Quantum Dot,Peri-implantitis,Periodontitis
更新于2025-09-19 17:13:59
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Q-Switch Nd:YAG Laser-Assisted Decontamination of Implant Surface
摘要： Peri-implantitis (PI) is an inflammatory disease of peri-implant tissues, it represents the most frequent complication of dental implants. Evidence revealed that microorganisms play the chief role in causing PI. The purpose of our study is to evaluate the cleaning of contaminated dental implant surfaces by means of the Q-switch Nd:YAG (Neodymium-doped Yttrium Aluminum Garnet) laser and an increase in temperature at lased implant surfaces during the cleaning process. Seventy-eight implants (titanium grade 4) were used (Euroteknika, Sallanches, France). Thirty-six sterile implants and forty-two contaminated implants were collected from failed clinical implants for different reasons, independent from the study. Thirty-six contaminated implants were partially irradiated by Q-switch Nd:YAG laser (1064 nm). Six other contaminated implants were used for temperature rise evaluation. All laser irradiations were calibrated by means of a powermetter in order to evaluate the effective delivered energy. The irradiation conditions delivered per pulse on the target were effectively: energy density per pulse of 0.597 J/cm2, pick powers density of 56 mW/cm2, 270 mW per pulse with a spot diameter of 2.4 mm, and with repetition rate of 10 Hz for pulse duration of 6 ns. Irradiation was performed during a total time of 2 s in a non-contact mode at a distance of 0.5 mm from implant surfaces. The parameters were chosen according to the results of a theoretical modeling calculation of the Nd:YAG laser fluency on implant surface. Evaluation of contaminants removal showed that the cleaning of the irradiated implant surfaces was statistically similar to those of sterile implants (p-value ≤ 0.05). SEM analysis confirmed that our parameters did not alter the lased surfaces. The increase in temperature generated at lased implant surfaces during cleaning was below 1 °C. According to our findings, Q-switch Nd:YAG laser with short pulse duration in nanoseconds is able to significantly clean contaminated implant surfaces. Irradiation parameters used in our study can be considered safe for periodontal tissue.
关键词： biofilm,dental implant,peri-implantitis,titanium surfaces decontamination
更新于2025-09-16 10:30:52
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Clinical evaluation of multiple peri-implant bony defect management by Er:YAG laser-assisted bone regenerative therapy
摘要： Conventional mechanical debridement is the main procedure for treating plaque-induced peri-implantitis, such as using plastic/metallic curettes, sand blasting machines, polishing by rubber cup/pumice powder, ultrasonic scalers, and titanium brushes. However, it is difficult to completely remove bacterial plaque with these instruments, especially in the micro-threads area. Recently, use of Er:YAG laser in dental field has increased for periodontal and peri-implantitis therapy, because Er:YAG laser is able to effectively ablate soft and hard tissues as well as calculus, and it can effectively debride the titanium surface with minimal thermal damage under suitable energy output. Meanwhile, the blood clot forming in the superficial areas of grafted bone by Er:YAG laser irradiation without water spray is useful for bone regenerative procedure, which is so called the Er:YAG laser-assisted bone regenerative therapy (Er-LBRT) developed by Taniguchi et al. This case report demonstrated a perspective option for implant surface debridement and simultaneously bone regeneration by Er-LBRT technique without usage of membrane coverage.
关键词： implant surface debridement,bone regenerative therapy,peri-implantitis,Er:YAG laser
更新于2025-09-12 10:27:22
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Thermal Testing of Titanium Implants and the Surrounding Ex-Vivo Tissue Irradiated With 9.3um CO2 Laser
摘要： Purpose: To measure the temperature rise and surface damage of titanium dental implants and the surrounding tissue in a pig jaw during 9.3-mm carbon dioxide (CO2) laser irradiation at various durations of time. Materials and Methods: Thermal analysis tests were performed on 12 implants with the same surface. Twelve implants mounted alone or in pig jaws were laser-irradiated with a 9.3-mm CO2 laser using 3 different power settings. The temperature of the implant body and the proximal tissues was measured with a J-Type Thermocouple after being laser-irradiated with 3 different power setting for 30, 60 seconds, and 2 minutes. Scanning electron microscope (SEM) and digital microscope images were also taken of the all the implants before and after laser irradiation to detect the presence or absence of surface damage. Results: Temperature analysis showed that in all cases the implant and the proximal tissue temperatures remained around the start temperatures of the implant and tissues with fluctuations of 63°C but never reached the upper threshold of 44°C, the temperature at which thermal injury to bone has been reported. Digital and SEM images that were taken of the implants showed an absence of surface damage at the cutting speed of 20% (0.7 W); however, cutting speeds of 30% to 100% (1.0–4.2 W) did yield surface damage. Conclusions: Laser irradiation of titanium implant surfaces using a 9.3-mm carbon dioxide laser with an average power of 0.7 W showed no increase in thermal temperature of the implant body and tissue temperatures as well as no evidence of implant surface damage.
关键词： thermal testing of implants,implant detoxification,implant complication,peri-implantitis,laser decontamination
更新于2025-09-12 10:27:22
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Temperature Changes and SEM Effects of Three Different Implants-Abutment Connection during Debridement with Er:YAG Laser: An Ex Vivo Study
摘要： The study aimed to evaluate a temperature increase in, and damage to, titanium implants during flapless laser debridement. The study analyzed 15 implants with various implant–abutment connections: a two-piece implant (n = 4) with a screw abutment (IA—Implant–Abutment) and a one-piece implant with a ball type fixture (BTF, n = 4) or fix type fixture (FTF, n = 4). The implants were placed in porcine mandibles 2 mm over a bone crest to imitate a peri-implantitis. The implants were debrided in contact mode for 60 s with a Er:YAG laser at fluence of 9.95 J/cm2 (G1 group: 50 mJ/30 Hz); 19.89 J/cm2 (G2 group: 100 mJ/30 Hz); 39.79 J/cm2 (G3 group: 200 mJ/30 Hz), or a scaler with a ceramic tip (G4 control group: 4 W/20 Hz). The temperature was measured with thermocouples at implant and abutment levels. The damage in the titanium surface (n = 3, non-irradiated implants from each type) was assessed using SEM (Scanning Electron Microscopy). The temperature increase at the implant level for the laser was higher at IA in contrast with FTF and BTF. (p < 0.05) The temperature change at the abutment level was lower for the scaler in contrast to Er:YAG laser at FTF. (p < 0.0002) C at 100 mJ/30 Hz and 50 mJ/30 Hz. Based on SEM analysis, cracks occurred on the surface of two-piece implants and were more pronounced. Cracks and the melting of the titanium surface of two-piece implants cleaned with Er:YAG laser at 100 or 200 mJ were observed. The specimens treated with the ultrasonic scaler with a plastic curette showed the remaining dark debris on the titanium surface. We recommend using Er:YAG laser at 50 mJ/30 Hz during flapless implants debridement.
关键词： titanium,peri-mucositis,peri-implantitis,two-piece implant,one-piece implant
更新于2025-09-11 14:15:04
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Efficacy of Antimicrobial Photodynamic Therapy as an Adjunctive to Mechanical Debridement in the Treatment of Peri-implant Diseases: A Randomized Controlled Clinical Trial
摘要： Introduction: The purpose of the present study was to assess the clinical effects of antimicrobial photodynamic therapy (PDT) after closed surface scaling in the treatment of peri-implant diseases. Methods: Ten patients with a total of 15 pairs of dental implants, showing clinical and radiographic signs of peri-implant diseases, were included in this study. In each patient, one implant randomly served as control implant and the other served as test implant. The control implants were treated with closed surface scaling only and the test implants received additionally PDT, using light with a wavelength of 630 nm and intensity of 2000 mw/cm2 for 120 seconds after application of photosensitizer in peri-implant sulcus. Clinical parameters were evaluated before and 1.5 and 3 months after treatment. Results: Statistical analysis showed significant differences in probing pocket depth (PPD), clinical attachment loss (CAL), bleeding on probing (BOP), and gingival index (GI) at each time point between the two groups. There were no statistically significant changes with respect to any of the parameters in the control group. Complete resolution of BOP at 3 months was achieved in 100% of test implants. At 1.5 and 3 months, there were significant differences in the mean probing depth and CAL gain measurements at implants in the test group. Conclusion: The present study revealed that adjunctive use of PDT following closed surface scaling could lead to clinical improvement of peri-implant diseases. Further studies are necessary to confirm our results.
关键词： photodynamic therapy,mechanical debridement,peri-implantitis,dental implant,clinical trial
更新于2025-09-11 14:15:04
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Antimicrobial efficacy of methylene blue-mediated photodynamic therapy on titanium alloy surfaces in vitro
摘要： Bacterial elimination using antimicrobial photodynamic therapy (aPDT) has been considered an alternative therapeutic modality in peri-implantitis treatment. The present in vitro study was to evaluate the dose-dependent and pH-dependent bactericidal effects of methylene blue (MB)-mediated aPDT on eliminating Gram-negative (P. gingivalis and A. actinomycetemcomitans) and Gram-positive (S. mutans) bacteria on sandblasting, large-grit and acid-etching (SLA)-pretreated titanium alloy. The effects of different MB concentrations (50, 100, and 200 μg/mL), the pH of the MB (4, 7, and 10), and irradiation time (0, 30, and 60 sec) on the bacterial viability and residual lipopolysaccharide (LPS) levels were examined. The variations in the pH of the MB solution after aPDT for 60 sec on the uncontaminated and contaminated specimens were also detected. The experimental results indicated that MB-mediated PDT could effectively kill the majority of bacteria on the titanium alloy surfaces of biofilm-contaminated implants compared with the MB alone. Of note, aPDT exhibited better antibacterial efficacy with increase in the MB concentration and irradiation time. While treated in an acidic solution on the biofilm-contaminated specimens, aPDT caused the pH to increase. By contrast, the initially high alkaline pH decreased to a value of about pH 8.5 after aPDT. Intriguingly, the neutral pH had minor changes, independent of the MB concentration and bacterial species. As expected, aPDT with higher MB concentration at higher pH environment significantly lowered the LPS concentration of A. actinomycetemcomitans and P. gingivalis. On the basis of the data, the aPDT with 200 μg/mL MB at pH 10 for 60 sec of irradiation time might be an effectively treatment to eliminate bacteria and LPS adherent to titanium surface, however, the use of the multispecies biofilm model and the evaluation of in vitro osteogenesis needed to be further evaluated.
关键词： Peri-implantitis,Antimicrobial activity,Lipopolysaccharide,Methylene blue,Photodynamic therapy
更新于2025-09-10 09:29:36
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Disinfect <i>Porphyromonas gingivalis</i> biofilm on titanium surface with combined application of chlorhexidine and antimicrobial photodynamic therapy
摘要： Various antimicrobial modalities have been proposed to treat peri-implantitis but resulted in limited outcomes. The aim of this in vitro study was to evaluate the disinfection efficacy of combined application of chlorhexidine digluconate (CHX) and antimicrobial photodynamic therapy (aPDT) of titanium surfaces previously contaminated with a porphyromonas gingivalis biofilm. P. gingivalis biofilms were grown on 32 polished and 32 sandblasted large-grit acid-etched (SLA) titanium surfaces. Titanium disks were allocated into four groups as follows: (i) immersed in phosphate-buffered saline (PBS), (ii) immersed in 0.2% CHX, (iii) application of aPDT, (iv) immersed in 0.2% CHX and subsequent aPDT. Residual bacteria were determined by microbial culture analysis and by scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM) imaging. Combination protocol (CHX+ aPDT) was the most effective in eradicating P. gingivalis (P < 0.05) on both polished and SLA surfaces. There was no significant difference in the number of remaining P. gingivalis between polished titanium disks and the SLA ones in four groups (P > 0.05). Under the limitation of this study, combined technique of preceding application of CHX and subsequent aPDT was shown to be an efficient method in reducing P. gingivalis numbers in both polished and SLA titanium surfaces.
关键词： chlorhexidine digluconate,Porphyromonas gingivalis,titanium surfaces,peri-implantitis,antimicrobial photodynamic therapy
更新于2025-09-09 09:28:46