Robot-assisted dental implant surgery procedure: A literature review.

Robot-assisted dental surgery has gained significant attention in the field of dental implant therapy as an alternative to conventional free-hand surgery. It addresses challenges faced by human operators, such as limited visibility, operator fatigue, and lack of experience, which can lead to errors. Dental implant robots offer improved precision, efficiency, and stability, enhancing implant accuracy and reducing surgical risks. Accurate placement of dental implants is crucial to avoid complications during and after surgery. Robotic guidance in dental implant surgery provides several benefits. Firstly, the robotic arm offers haptic feedback, allowing physical guidance when placing the implant in the desired position. Secondly, a patient tracker integrated into the robotic system monitors patient movement and provides real-time feedback on a screen. This feature ensures that the surgeon is aware of any changes and can adjust accordingly. Lastly, the robotic system operates under human-robot collaboration, with the surgeon maintaining control and oversight throughout the procedure. Therefore, the objective of the current study is to review the dental implant robots, as well as accuracy and efficiency (e.g. operation and preparation time) of robot-assisted dental implant surgery procedures.

Bioinformatics analysis of photoexcited natural flavonoid glycosides as the inhibitors for oropharyngeal HPV oncoproteins.

The presence of oropharyngeal human papillomavirus (HPV)-18 E6 and E7 oncoproteins is highly significant in the progression of oropharyngeal cancer. Natural flavonoid compounds have potential as photosensitizers for light-activated antimicrobial therapy against HPV-associated oropharyngeal cancer. This study evaluated five natural flavonoid glycosides including Fisetin, Kaempferol, Morin, Myricetin, and Quercetin as photosensitizers against HPV-18 E6 and E7 oncoproteins using computational methods. After obtaining the amino acid sequences of HPV-18 E6 and E7, various tools were used to predict and verify their properties. The PubChem database was then examined to identify potential natural flavonoid glycosides, followed by predictions of their drug-likeness and ADMET properties. Subsequently, molecular docking was conducted to enhance the screening accuracy and to gain insights into the interactions between the natural compounds and the active sites of HPV-18 E6 and E7 oncoproteins. The protein structures of E6 and E7 were predicted and validated to be reliable. The results of molecular docking demonstrated that Kaempferol exhibited the highest binding affinity to both E6 and E7. All compounds satisfied Lipinski's rules of drug-likeness, except Myricetin. They showed high absorption, distribution volume and similar ADMET profiles with no toxicity. In summary, natural flavonoid glycosides, especially Kaempferol, show potential as photosensitizers for antimicrobial photodynamic therapy against HPV-associated oropharyngeal cancer through inhibition of E6 and E7 oncoproteins. These findings provide insights into the development of novel therapeutic strategies based on antimicrobial photodynamic therapy.

Antimicrobial photodynamic therapy for managing the peri-implant mucositis and peri-implantitis: A systematic review of randomized clinical trials.

BACKGROUND: The presence of peri­implant inflammation including peri­implant mucositis and peri­implantitis, is a crucial factor that impacts the long-term stability and success of dental implants. This review aimed to evaluate the safety and effectiveness of antimicrobial photodynamic therapy (aPDT) as an adjuvant therapy option for managing peri­implant mucositis and peri­implantitis. METHODS: We systematically searched the PubMed/MEDLINE, Cochrane Library, Scopus, and Google Scholar databases (no time limitation). The review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, and the quality of the studies was assessed using the Cochrane Collaboration tool. RESULTS: Of 322 eligible articles, 14 studies were included in this review. The heterogeneity and poor quality of the articles reviewed prevented a meta-analysis. The reviewed articles used a light source (60 s, 1 session) with a wavelength of 635 to 810 nm for optimal tissue penetration. These studies showed improved clinical parameters such as probing depth, bleeding on probing (BOP), and plaque index after aPDT treatment. However, in smokers, BOP increased after aPDT. Compared to conventional therapy, aPDT had a longer-term antimicrobial effect and reduced periopathogens like Porphyromonas gingivalis, as well as inflammatory factors such as Interleukin (IL)-1ß, IL-6, and Tumor necrosis factor alpha (TNF-α). No undesired side effects were reported in the studies. CONCLUSION: Although the reviewed articles had limitations, aPDT showed effectiveness in improving peri­implant mucositis and peri­implantitis. It is recommended as an adjunctive strategy for managing peri­implant diseases, but further high-quality research is needed for efficacy and long-term outcomes.

Effects of Kojic Acid-mediated Sonodynamic Therapy as a Matrix Metalloprotease-9 Inhibitor against Oral Squamous Cell Carcinoma: A Bioinformatics Screening and in vitro Analysis.

BACKGROUND: Oral squamous cell carcinoma (OSCC) is a type of cancer that is responsible for a significant amount of morbidity and mortality worldwide. Researchers are searching for promising therapeutic methods to manage this cancer. In this study, an in silico approach was used to evaluate the activity of sonodynamic therapy (SDT) based on the use of Kojic acid as a sonosensitizer to inhibit matrix metalloprotease-9 (MMP-9) in OSCC. MATERIALS AND METHODS: The three-dimensional structure of MMP-9 was predicted and validated by computational approaches. The possible functional role of MMP-9 was determined in terms of Gene Ontology (GO) enrichment analysis. In silico, molecular docking was then performed to evaluate the binding energies of Kojic acid with MMP-9, and ADME parameters and toxicity risks were predicted. The pharmacokinetics and drug-likeness properties of Kojic acid were assessed. Moreover, after the determination of the cytotoxicity effect of Kojic acid-mediated SDT, the change of mmp-9 gene expression was assessed on OSCC cells. RESULTS: The results of the study showed that Kojic acid could efficiently interact with MMP-9 protein with a strong binding affinity. Kojic acid obeyed Lipinski's rule of five without violation and exhibited drug-likeness. The cytotoxic effects of Kojic acid and ultrasound waves on the OSCC cells were dose-dependent, and the lowest expression level of the mmp-9 gene was observed in SDT. CONCLUSIONS: Overall, Kojic acid-mediated SDT as an MMP-9 inhibitor can be a promising adjuvant treatment for OSCC. The study highlights the potential of in silico approaches to evaluate therapeutic methods for cancer treatment.

Effects of Antimicrobial photosensitizers of Photodynamic Therapy (PDT) to Treat Periodontitis.

Along with antimicrobial photosensitizers or antimicrobial photodynamic therapy (aPDT), Photodynamic therapy (PDT) is a therapeutic approach in which lasers and different photosensitizers (PSs) are used to eradicate periodontopathic bacteria in aggressive and chronic periodontitis. Periodontitis is a localized infectious disease caused by periodontopathic bacteria and can destroy bones and tissues surrounding and supporting the teeth. The aPDT system has been shown by in vitro studies to have high bactericidal efficacy. It was demonstrated that aPDT has low local toxicity, can speed up dental therapy, and is cost-effective. Several photosensitizers (PSs) are available for each type of light source which did not induce any damage to the patient and are safe. In recent years, significant advances have been made in aPDT as a non-invasive treatment method, especially in treating infections and cancers. Besides, aPDT can be perfectly combined with other treatments. Hence, this survey focused on the effectiveness and mechanism of aPDT of periodontitis by using lasers and the most frequently used antimicrobial PSs such as methylene blue (MB), toluidine blue ortho (TBO), indocyanine green (ICG), Malachite green (MG) (Triarylmethanes), Erythrosine Dyes (ERY) (Xanthenes dyes), Rose bengal (RB) (Xanthenes dyes), Eosin-Y (Xanthenes dyes), Radachlorin group and Curcumin. The aPDT with these PSs can reduce pathogenic bacterial loads in periodontitis. Therefore, it is clear that there is a bright future for using aPDT to fight microorganisms causing periodontitis.

Anti-multispecies microbial biofilms and anti-inflammatory effects of antimicrobial photo-sonodynamic therapy based on acrylic resin containing nano-resveratrol.

BACKGROUND: Polymethylmethacrylate (PMMA)-based removable orthodontic appliances are susceptible to microbial colonization due to the surface porosity, and accumulating the biofilms causes denture stomatitis. the present study evaluated the anti-biofilm and antiinflammatory effects of antimicrobial photo-sonodynamic therapy (aPSDT) against multispecies microbial biofilms (Candida albicans, Staphylococcus aureus, Streptococcus sobrinus, and Actinomyces naeslundii) formed on acrylic resin modified with nanoresveratrol (NR). MATERIALS AND METHODS: Following the determination of the minimum biofilm inhibitory concentration (MBIC) of NR, in vitro anti-biofilm activity of NR was evaluated. The antibiofilm efficacy against multispecies microbial biofilm including C. albicans, S. aureus, S. sobrinus, and A. naeslundii, were assessed by biofilm inhibition test and the results were measured. To reveal the anti-inflammatory effects of aPSDT on human gingival fibroblast (HGF) cells, the gene expression levels of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) were evaluated via quantitative real-time polymerase chain reaction (qRT-PCR). RESULTS: According to the results, the MBIC dose of NR against multispecies microbial biofilm was considered 512 µg/mL. The highest biofilm reduction activity was observed in MBIC treated with aPSDT and 2 × MBIC exposed to light emitting diode (LED) and ultrasound waves (UW). The expression level of TNF-α and IL-6 genes were significantly increased when HGF cells were exposed to multispecies microbial biofilms (P<0.05), while after treatment with aPSDT, the expression levels of genes were significantly downregulated in all groups (P<0.05). CONCLUSION: Overall, NR-mediated aPSDT reduced the growth of the multispecies microbial biofilm and downregulated the expression of TNF-α and IL-6 genes. Therefore, modified PMMA with NR can be serving as a promising new orthodontic acrylic resin against multispecies microbial biofilms and the effect of this new material is amplified when exposed to LED and UW.

Virtual screening and computational simulation analysis of antimicrobial photodynamic therapy using propolis-benzofuran A to control of Monkeypox.

BACKGROUND: Monkeypox is a viral zoonotic disease and there are no available treatments that specifically target the monkeypox virus. Antimicrobial photodynamic therapy (aPDT) is a non-invasive approach that has been introduced as a targeted adjuvant treatment against various microbial infections. In this study, we used a computational strategy to investigate the potential of aPDT using propolis-benzofuran A against the Monkeypox virus. METHODS: In this in silico study, the evaluation of drug-likeness, molecular properties, and bioactivity of propolis-benzofuran A was carried out using SwissADME. Pro-Tox II and OSIRIS servers were used to identify the organ toxicities and toxicological endpoints of propolis-benzofuran A. Molecular docking approach was employed to screen the potential binding modes of propolis-benzofuran A ligand with the Monkeypox virus A48R protein (PDB ID: 2V54). RESULTS: The results of the computational investigation revealed that propolis-benzofuran A obeyed all the criteria of Lipinski's rule of five and exhibited drug-likeness. The photosensitizing agent tested was categorized as toxicity class-5 and was found to be non-hepatotoxic, non-carcinogenic, non-mutagenic, and non-cytotoxic. The docking studies employing a predicted three-dimensional model of Monkeypox virus A48R protein with propolis-benzofuran A ligand exhibited good binding affinity (-7.84 kcal/mol). DISCUSSION: The computational simulation revealed that propolis-benzofuran A had a strong binding affinity with the Monkeypox virus A48R protein. Hence, aPDT based on this natural photosensitizer can be proposed as an adjuvant treatment against the Monkeypox virus.

Quorum quenching of Streptococcus mutans via the nano-quercetin-based antimicrobial photodynamic therapy as a potential target for cariogenic biofilm.

BACKGROUND: Quorum sensing (QS) system can regulate the expression of virulence factors and biofilm formation in Streptococcus mutans. Antimicrobial photodynamic therapy (aPDT) inhibits quorum quenching (QQ), and can be used to prevent microbial biofilm. We thereby aimed to evaluate the anti-biofilm potency and anti-metabolic activity of nano-quercetin (N-QCT)-mediated aPDT against S. mutans. Also, in silico evaluation of the inhibitory effect of N-QCT on the competence-stimulating peptide (CSP) of S. mutans was performed to elucidate the impact of aPDT on various QS-regulated genes. METHODS: Cytotoxicity and intracellular reactive oxygen species (ROS) generation were assessed following synthesis and confirmation of N-QCT. Subsequently, the minimum biofilm inhibitory concentration (MBIC) of N-QCT against S. mutans and anti-biofilm effects of aPDT were assessed using colorimetric assay and plate counting. Molecular modeling and docking analysis were performed to confirm the connection of QCT to CSP. The metabolic activity of S. mutans and the expression level of various genes involved in QS were evaluated by flow cytometry and reverse transcription quantitative real-time PCR, respectively. RESULTS: Successful synthesis of non-toxic N-QCT was confirmed through several characterization tests. The MBIC value of N-QCT against S. mutans was 128 µg/mL. Similar to the crystal violet staining, the results log10 CFU/mL showed a significant degradation of preformed biofilms in the group treated with aPDT compared to the control group (P < 0.05). Following aPDT, metabolic activity of S. mutans also decreased by 85.7% (1/2 × MBIC of N-QCT) and 77.3% (1/4 × MBIC of N-QCT), as compared to the control values (P < 0.05). In silico analysis showed that the QCT molecule was located in the site formed by polypeptide helices of CSP. The relative expression levels of the virulence genes were significantly decreased in the presence of N-QCT-mediated aPDT (P < 0.05). CONCLUSIONS: The combination of N-QCT with blue laser as a QQ-strategy leads to maximum ROS generation, disrupts the microbial biofilm of S. mutans, reduces metabolic activity, and downregulates the expression of genes involved in the QS pathway by targeting genes of the QS signaling system of S. mutans.

Antimicrobial and anti-biofilm potencies of dermcidin-derived peptide DCD-1L against Acinetobacter baumannii: an in vivo wound healing model.

BACKGROUND: The global emergence of Acinetobacter baumannii resistance to most conventional antibiotics presents a major therapeutic challenge and necessitates the discovery of new antibacterial agents. The purpose of this study was to investigate in vitro and in vivo anti-biofilm potency of dermcidin-1L (DCD-1L) against extensively drug-resistant (XDR)-, pandrug-resistant (PDR)-, and ATCC19606-A. baumannii. METHODS: After determination of minimum inhibitory concentration (MIC) of DCD-1L, in vitro anti-adhesive and anti-biofilm activities of DCD-1L were evaluated. Cytotoxicity, hemolytic activity, and the effect of DCD-1L treatment on the expression of various biofilm-associated genes were determined. The inhibitory effect of DCD-1L on biofilm formation in the model of catheter-associated infection, as well as, histopathological examination of the burn wound sites of mice treated with DCD-1L were assessed. RESULTS: The bacterial adhesion and biofilm formation in all A. baumannii isolates were inhibited at 2 × , 4 × , and 8 × MIC of DCD-1L, while only 8 × MIC of DCD-1L was able to destroy the pre-formed biofilm in vitro. Also, reduce the expression of genes involved in biofilm formation was observed following DCD-1L treatment. DCD-1L without cytotoxic and hemolytic activities significantly reduced the biofilm formation in the model of catheter-associated infection. In vivo results showed that the count of A. baumannii in infected wounds was significantly decreased and the promotion in wound healing by the acceleration of skin re-epithelialization in mice was observed following treatment with 8 × MIC of DCD-1L. CONCLUSIONS: Results of this study demonstrated that DCD-1L can inhibit bacterial attachment and biofilm formation and prevent the onset of infection. Taking these properties together, DCD-1L appears as a promising candidate for antimicrobial and anti-biofilm drug development.

Modulation of the triggered apoptosis by nano emodin transfersome-mediated sonodynamic therapy on head and neck squamous cell carcinoma cell lines.

BACKGROUND: Non-invasive sonodynamic therapy (SDT) is a new treatment modality that uses low-intensity ultrasound to activate a non-toxic sensitizing chemical agent for cancer therapy in a site-directed manner. This study aimed to investigate the anti-cancer effects of ultrasound combined with nano emodin transfersome (NET) on head and neck squamous cell carcinoma (HNSCC) cell lines. MATERIALS AND METHODS: A transfersome form of nano emodin as a novel sono-responsive nanomaterial was synthesized to enhance the accumulation and penetration of nanoparticles. iIn vitro experiments including hemolytic activity, cell proliferation, intracellular reactive oxygen species (ROS) generation, apoptosis induction, DNA fragmentation, and mRNA expressions of caspase 3 and 9 were conducted to explore the anti-cancer effects of NET-SDT on FaDu and CAL-27 cell lines. RESULTS: Characterization tests showed the round and uniform morphology of NET with transfersome structure, resulting in a high drug-loading content and encapsulation efficiency. No significant hemolytic activity was observed (P > 0.05). Cytotoxicity gradually increased with increasing concentrations of NET, so that 10 × 10-4 g/L of NET plus 5 min ultrasound irradiation at a frequency of 1 MHz and ultrasonic intensity of 2 W/cm2 effectively killed 98.2 % and 97.3 % of FaDu and CAL-27 cell lines, respectively (P < 0.05). We found that ROS generation in NET-SDT was dose-dependent and the triggered apoptosis and caspase-3/9 gene expression levels were significantly enhanced as the concentration of NET increased (P < 0.05). No significant difference was found in the rate of apoptosis induction and gene expression between two cell lines. CONCLUSIONS: Our data demonstrated that SDT with NET as a sonosensitizer can induce apoptosis and significantly decrease cell viability of HNSCC cell lines, which represents the role of NET-SDT as a potent anti-cancer modality.

The Effect of Indocyanine Green Antimicrobial Photothermal/Photodynamic Therapy on the Expression of BCL-2 and BAX Messenger RNA Levels in Human Gingival Fibroblast Cells.

BACKGROUND: Antimicrobial photothermal/photodynamic therapy (PTT/PDT) with indocyanine green (ICG) is an adjuvant therapeutic approach in the treatment of periodontitis. To explore whether PTT/PDT with ICG causes cell death by apoptosis in human gingival fibroblast (HGF) cells, BAX and BCL-2 genes expression as key events for apoptosis were evaluated in this study. MATERIALS AND METHODS: HGF cells were treated with: 1) different concentrations (500-2000 µg/mL) of ICG alone, 2) Diode laser irradiation alone with a fluency of 39.06 J/cm2; 3) PTT/PDT combined different concentrations (500-2000 µg/mL) of ICG with an 808 nm diode laser with a fluency of 39.06 J/cm2, and 4) controls (untreated cells). After that, BAX and BCL-2 messenger RNA levels were evaluated by real-time quantitative reverse transcription PCR. RESULTS: PTT/PDT with 500 µg/mL of ICG caused significant increases in the expression of the BAX gene, with an 8.5-fold increase, which was approximately 7- and 8.5-fold higher than PTT/PDT with ICG for 1500 and 2000 µg/mL of ICG, respectively, indicating induction of apoptosis in HGF cells. ICG (in different test concentrations), diode laser, and PTT/PDT with ICG (1500 and 2000 µg/mL of ICG) treatment displayed insignificant increases in expression levels of BAX (all p>0.05). Our experiments showed an insignificant increase (1.1-1.6-fold) in the expression of BCL-2 after ICG, diode laser, and PTT/PDT with ICG treatment (all p>0.05). CONCLUSIONS: This study suggests that various concentration of ICG can be the diverse expression of BAX responses to PTT/PDT on HGF cells.

Ex vivo comparison of antibacterial efficacy of conventional chemomechanical debridement alone and in combination with light-activated disinfection and laser irradiation against Enterococcus faecalis biofilm.

BACKGROUND AND OBJECTIVES: Intracanal disinfection plays an important role in endodontic treatment success. Enterococcus faecalis (E. faecalis) is a resistant microorganism responsible for endodontic infections. We aimed to assess the bactericidal effects of three disinfection methods on E. faecalis biofilm. MATERIALS AND METHODS: Fifty-five freshly extracted single-rooted human teeth were evaluated. A barbed broach was used to extract the pulp tissue. No further root canal preparation was performed. Specimens were sterilized with gamma radiation, and inoculated with E. faecalis suspension. They were then incubated for 4 days and 4 weeks. Biofilm formation was confirmed using a scanning electron microscope (SEM). The teeth were randomly assigned to three subgroups (n = 7) to assess the antimicrobial efficacy of the following three disinfection methods against immature (4-day) and mature (4-week) biofilms: the conventional chemomechanical debridement (CCMD), CCMD + light-activated disinfection (LAD; 810 nm, 0.3 W, 120 J/cm2) with indocyanine Green (EmunDo) as photosensitizer and CCMD + diode laser irradiation (810 nm, 2 W). The teeth were then longitudinally split into two halves and the colony count was reported as colony forming units (CFUs) to assess bacterial viability after each disinfection protocol. RESULTS: None of the disinfection methods could completely remove the biofilm. CCMD + LAD caused the highest and CCMD + diode laser caused the lowest reduction in biofilm. Antibacterial efficacy was significantly lower against the mature (4-week) biofilm compared with immature (4-day) biofilm in all groups (P < 0.05). CONCLUSION: All three disinfection methods were effective for partial elimination of E. faecalis biofilm. But CCMD + LAD was significantly more efficacious in decreasing both mature and immature biofilms.

The Photomodulation Activity of Metformin Against Oral Microbiome.

Periodontitis is one of the most common inflammatory diseases of the periodontium, which results in the inflammatory destruction of supporting structures around teeth and is closely associated with the development of systemic disease. Due to a wide variety of antibiotic resistance periodontopathic bacteria, photodynamic therapy (PDT) is a non-invasive adjunctive therapeutic modality that is capable of destroying the whole range of microbes. Metformin (Metf) is an antidiabetic drug, and recent studies suggest that cancer patients who receive Metf and are exposed to radiotherapy and chemotherapy show better outcomes. Our surveys in this review introduce Metf as a potent stimulus in increasing the efficacy of PDT in the induction of destruction in microbial cells.

Effects of Micro RNAs and their Targets in Periodontal Diseases.

RNA interference (RNAi) or Post-Transcriptional Gene Silencing is a strong mechanism of gene silencing which is moderated by MicroRNAs (miRNAs), underlying many fields of eukaryotic biology. The miRNAs are small noncoding RNAs and a gene regulation expression system which showing a tissue-specific expression pattern, and inhibits protein synthesis. For the first time, miRNA has been seen in Caenorhabditis elegans. They play an important role in signaling pathways of various diseases especially periodontal disease during periodontal inflammation and oral cancers. The most important miRNAs in periodontal diseases and oral squamous cell carcinoma are miR-142-3p, miR-146a, miR-155, miR-203, and miR- 223. One of the most important diseases in association with gingival infectious is periodontal diseases which if left untreated, would lead to tooth loss. Hence, the aim of the present study is to focus the effects of miRNAs and their targets in diseases which are mentioned above.

Carnosine-graphene oxide conjugates decorated with hydroxyapatite as promising nanocarrier for ICG loading with enhanced antibacterial effects in photodynamic therapy against Streptococcus mutans.

Antimicrobial photodynamic therapy (aPDT) has been emerged as a noninvasive strategy to remove bacterial contaminants such as S. mutans from the tooth surface. Photosensitizer (PS), like indocyanine green (ICG), plays a key role in this technique which mainly suffers from the poor stability and concentration-dependent aggregation. An appropriate nanocarrier (NC) with enhanced antibacterial effects could overcome these limitations and improve the efficiency of ICG as a PS. In this study, various ICG-loaded NCs including graphene oxide (GO), GO-carnosine (Car) and GO-Car/Hydroxyapatite (HAp) were synthesized and characterized by Fourier Transform Infrared Spectroscopy (FT-IR), X-ray Diffraction (XRD), Filed Emission Scanning Electron Microscopy (FE-SEM), Energy Dispersive Spectroscopy (EDS), Zeta Potential and Ultraviolet-Visible spectrometry (UV-Vis). The colony forming unit and crystal violet assays were performed to evaluate the antimicrobial and anti-biofilm properties of PSs against S. mutans. The quantitative real-time PCR approach was also applied to determine the expression ratio of the gtfB gene in S. mutans. The zeta potential analysis and UV-Vis spectrometry indicated successful loading of ICG onto/into NCs. GO-Car/HAp showed highest amount of ICG loading (57.52%) and also highest aqueous stability after one week (94%). UV-Vis spectrometry analyses disclosed a red shift from 780 to 800 nm for the characteristic peak of ICG-loaded NCs. In the lack of aPDT, GO-Car@ICG showed the highest decrease in bacterial survival (86.4%) which indicated that Car could significantly promote the antibacterial effect of GO. GO@ICG, GO-Car@ICG and GO-Car/HAp@ICG mediated aPDT, dramatically declined the count of S. mutans strains to 91.2%, 95.5% and 93.2%, respectively (P < 0.05). The GO@ICG, GO-Car@ICG, GO-Car/HAp@ICG significantly suppressed the S. mutans biofilm formation by 51.4%, 63.8%, and 56.8%, respectively (P < 0.05). The expression of gtfB gene was considerably reduced to 6.0, 9.0 and 7.9-fold after aPDT in the presence of GO@ICG, GO-Car@ICG, GO-Car/HAp@ICG, respectively (P < 0.05). It could be concluded that the multi-functionalized GO as a novel nanocarrier could significantly enhance the ICG loading, stability, and improve its inhibitory effects as a photosensitizer in aPDT against S. mutans. These findings might provide opportunity for efficient treatment of local dental infections.

Investigation of arginine A-specific cysteine proteinase gene expression profiling in clinical Porphyromonas gingivalis isolates against photokilling action of the photo-activated disinfection.

Porphyromonas gingivalis is a significant root canal pathogen capable of causing endodontic infections, which during their treatment may receive sub-lethal doses of photo-activated disinfection (sPAD). As sPAD can influence microbial virulence, this study was designed to evaluate the effect of sPAD on gene expression level of arginine A-specific cysteine proteinase (rgpA), as one of the underlying virulence factors involved in the development of endodontic infection via P. gingivalis strains. To find out the sPAD against 16 clinical isolates of PAD-resistant P. gingivalis that were isolated in vivo, we used toluidine blue O (TBO), methylene blue (MB), and indocyanine green (ICG) as the photosensitizers, which were excited with specific wavelength of light in vitro. Quantitative real-time PCR (qRT-PCR) was then applied to monitor gene expression of rgpA in P. gingivalis isolates to characterize its virulence agent and understand the effect of sPAD on its pathogenicity. Maximal sPAD that could not decrease the count of P. gingivalis isolates were 6.25, 15.6, and 25 µg/mL at fluencies of 171.87, 15.6, and 93.75 J/cm2 for TBO, ICG, and MB, respectively. ICG-sPAD could suppress the rgpA gene expression about 14-fold, while MB and TBO-mediated sPAD could cause the attenuation of rgpA expression about 4.9- and 11.6-fold, respectively. ICG-sPAD with the maximum ability to reduce rgpA gene expression compared with other photosensitizers can be an appropriate candidate for the treatment of endodontic infections.

Effect of TiO2 nanoparticles incorporation on antibacterial properties and shear bond strength of dental composite used in Orthodontics

ABSTRACT Introduction: Plaque accumulation and bond failure are drawbacks of orthodontic treatment, which requires composite for bonding of brackets. As the antimicrobial properties of TiO2 nanoparticles (NPs) have been proven, the aim of this study was to evaluate the antimicrobial and mechanical properties of composite resins modified by the addition of TiO2 NPs. Methods: Orthodontics composite containing 0%, 1%, 5% and 10% NPs were prepared. 180 composite disks were prepared for elution test, disk agar diffusion test and biofilm inhibition test to collect the counts of microorganisms on three days, measure the inhibition diameter and quantify the viable counts of colonies consequently. For shear bond strength (SBS) test, 48 intact bovine incisors were divided into four groups. Composites containing 0%, 1%, 5% and 10% NPs were used for bonding of bracket. The bracket/tooth SBS was measured by using an universal testing machine. Results: All concentration of TiO2 NPs had a significant effect on creation and extension of inhibition zone. For S. mutans and S. sanguinis, all concentration of TiO2 NPs caused reduction of the colony counts. Composite containing 10% TiO2 NPs had significant effect on reduction of colony counts for S. mutans and S. sanguinis in all three days. The highest mean shear bond strength belonged to the control group, while the lowest value was seen in 10% NPs composite. Conclusions: Incorporating TiO2 nanoparticles into composite resins confer antibacterial properties to adhesives, while the mean shear bond of composite containing 1% and 5% NPs still in an acceptable range.

RESUMO Introdução: o acúmulo de placa e as descolagens de braquetes são algumas desvantagens presentes no tratamento ortodôntico, no qual se requer o uso de materiais compósitos para a colagem dos braquetes. Objetivo: tendo em vista que as propriedades antimicrobianas das nanopartículas (NPs) de TiO2 já foram confirmadas, o objetivo do presente estudo foi avaliar as propriedades antimicrobianas e mecânicas de resinas compostas modificadas pela adição de NPs de TiO2. Métodos: compósitos ortodônticos contendo 0%, 1%, 5% e 10% de NPs foram preparados. Cento e oitenta discos de compósito foram preparados para o teste de eluição, o ensaio de difusão em ágar por disco, e o ensaio de inibição da formação de biofilme, para se calcular as contagens de microrganismos ao longo de três dias, medir o diâmetro da inibição e, consequentemente, quantificar as contagens de colônias viáveis. Para o teste de resistência da colagem ao cisalhamento (SBS), 48 incisivos bovinos intactos foram divididos em quatro grupos, nos quais os compósitos contendo 0%, 1%, 5% e 10% de NPs foram utilizados para colagem dos braquetes. A SBS da interface braquete/dente foi medida em uma máquina universal de ensaios. Resultados: todas as concentrações de NPs de TiO2 apresentaram efeito significativo na formação e na extensão da zona de inibição. Para o S. mutans e o S. sanguinis, todas as concentrações de NPs de TiO2 causaram redução na contagem das colônias. O compósito contendo 10% de NPs de TiO2 apresentou uma diminuição significativa na contagem de colônias de S. mutans e S. sanguinis durante os três dias. A média mais alta da SBS foi observada no grupo controle, enquanto o valor mais baixo foi observado para o compósito com 10% de NPs. Conclusões: a incorporação de nanopartículas de TiO2 nas resinas compostas lhes conferiu propriedades antibacterianas, e o valor médio da SBS das resinas contendo 1% e 5% de NPs apresentou-se dentro de uma faixa aceitável.

Evaluation of photodynamic therapy effect along with colistin on pandrug-resistant Acinetobacter baumannii.

BACKGROUND AND AIMS: Pandrug-resistant Acinetobacter baumannii (PDRAB) are including colistin resistant starins (CoRAB) which cause infections potentially untreatable infections. Recently, incidence of these strains are increasing worldwide. Therefore, new approaches, methods and strategies are urgently needed for treatment and eradication of infections due to PDRAB. So the aim of this study was to evaluate the efficacy of photodynamic therapy (PDT) in combination treatment with colistin against PDRAB. MATERIALS AND METHODS: PDRAB which was isolated from burn patients was used as a test strain. PDT carried out in which toluidine blue O (TBO) and light-emitting diode (LED) were used as photosensitizer and radiation source, respectively. Then, the effect of PDT plus colistin was evaluated on CoRAB and the colony-forming units of each tested groups calculated. Finally, confirmation of antibacterial activity of combination therapy was carried out using scanning electron microscope. RESULTS: PDT declined bacterial count in comparing with control group by 83.7% of killing percentage, in other words, less than one log reduction. While PDT in combination with colistin showed high synergetic effect against A. baumannii in all concentrations of colistin tested by 100% of killing percentage with 9-log reduction. CONCLUSIONS: According to our results, PDT alone couldn't eliminate all of the treated bacterial cells. But when combined with colistin, it killed all of the treated bacterial cells in all tested concentrations. Also PDT decreased the minimal inhibitory concentration of colistin against PDRAB by more than 11 fold.

Antibiotic susceptibility of Helicobacter pylori strains isolated from Iranian children: High frequency of A2143G point mutation associated with clarithromycin resistance.

OBJECTIVE: Increasing antibiotic resistance in Helicobacter pylori is a global concern and is associated with treatment failure. The aim of this study was to evaluate antibiotic resistance of H. pylori to different antibiotics including amoxicillin, erythromycin, ciprofloxacin, furazolidone, tetracycline, metronidazole and clarithromycin. In addition, ​detection of A2143G mutation in clarithromycin resistant isolates was performed using real-time PCR technique. METHODS: Ninety patients with upper gastrointestinal symptoms were enrolled in this study. H. pylori were isolated from 32 specimens and the resistance rate of these strains to amoxicillin, erythromycin, ciprofloxacin, furazolidone, and tetracycline was tested by disc agar diffusion method. The resistance level to metronidazole and clarithromycin was determined by agar dilution method. The presence of A2143G point mutation in clarithromycin resistant isolates was determined using real-time PCR technique. RESULTS: The resistance rates to amoxicillin, erythromycin, ciprofloxacin, furazolidone, tetracycline, metronidazole and clarithromycin were 53%, 50%, 37.5%, 62.5%, 25%, 62.5% and 22%, respectively. The A2143G point mutation was detected in 71% of clarithromycin resistant strains (5 out of 7). CONCLUSIONS: The prevalence of H. pylori resistance to metronidazole, ciprofloxacin, erythromycin, amoxicillin and furazolidone in Iran is high. Determination of antibiotic susceptibility plays an important role in selecting of the appropriate anti H. pylori regimen.

Effect of photodynamic therapy based on indocyanine green on expression of apoptosis-related genes in human gingival fibroblast cells.

BACKGROUND: Periodontal diseases refer to inflammation of the gingiva, induction of apoptosis in human gingival fibroblast cells, destruction of the surrounding tissues, and early bone loss resulting in infections due to the pathogenic activity of the microorganisms and the host immune inflammatory responses. Recent investigations have suggested that antimicrobial photodynamic therapy (aPDT) can be an adjunct treatment therapy for periodontal infections. AIM: To prove the lack of side effects of PDT on periodontal tissues, we investigated the expression of BAX and BCL-2 genes that are involved in apoptosis after the PDT on human gingival fibroblast (HGF) cells. MATERIALS AND METHODS: In this study the effect of PDT based on indocyanine green (ICG) as a photosensitizer with the diode laser were tested on the expression of BAX and BCL-2 genes in monolayers of HGF cells. The effects of PDT on the expression of BAX and BCL-2 genes were evaluated by real-time quantitative reverse transcription PCR. RESULTS: The results of the genes expression analysis revealed that ICG-PDT at concentrations 1000µg/mL, induced the significant expression of BAX in HGF cells; however, the laser irradiation as well as ICG showed no significant effects on the expression of these genes. Treatment with ICG alone, laser irradiation and ICG-PDT caused no observable BCL-2 gene expression changes between the tested and control groups. CONCLUSION: Our findings indicate that ICG-PDT at 1000µg/mL of ICG with the exposure time of 60s for the diode laser would appear to be an inducer of apoptosis in HGF at transcriptome level.