Evaluation of antimicrobial photodynamic therapy with acidic methylene blue for the treatment of experimental periodontitis

Efficacy of methylene blue-mediated antimicrobial photodynamic therapy on clinical and radiographic outcomes among patients with periodontal diseases: A systematic review and meta-analysis of randomized controlled trials

OBJECTIVE

This study aimed to assess the influence of methylene blue (MB)-mediated adjunctive antimicrobial photodynamic therapy (aPDT) when compared to conventional mechanical debridement (MD) alone on periodontal clinical and radiographic outcomes among periodontitis patients.

METHODS

Randomized clinical trials (RCTs) were incorporated by conducting an electronic search in Web of Science, Scopus, and PubMed for articles published in English up to August 2023 to address the following focused question based on the PICO format: "Whether the application of MB-mediated aPDT as an adjunctive to MD (Intervention) leads to improved periodontal clinical and/or radiographic outcomes (Outcome) among participants with and without periodontal diseases (Population) as compared to MD alone (Conparison)". The risk of bias (RoB) of the included studies was assessed using the modified Jadad scale. A meta-analysis was conducted, and it included the presentation of the standard mean difference (SMD) along with a 95 % confidence interval (CI).

RESULTS

In total, 11 studies were included in this systematic review and meta-analysis. The meta-analysis demonstrated statistically significant improvements in periodontal plaque index (SMD: -0.72 % [95 % CI: -0.99 % to -0.45 %]; p<0.00001), probing depth (SMD: -0.38 % [95 % CI: -0.57 % to -0.19 %; p<0.00001), and bleeding on probing (SMD: -0.44 % [95 % CI: -0.68 % to -0.20 %]; p = 0.0003) scores at the final follow-up visit after the application of MB-mediated aPDT in comparison with MD alone. Nevertheless, there was no statistically significant difference was observed in periodontal clinical attachment level values (SMD: -0.01 % [95 % CI: -0.21 % to 0.19 %]; p = 0.95) between the control group and the experimental group. Six studies achieved a low RoB, five were rated as having medium RoB, while no study received a high RoB.

CONCLUSION

MB-mediated aPDT, when used as an adjunct to conventional MD contributes to the improvement of periodontal clinical outcomes including PI, PD, and BOP in patients with periodontitis.

TRPC expression in human periodontal ligament cells and the periodontal tissue of periodontitis mice: a preliminary study

BACKGROUND

Transient receptor potential canonical (TRPC) channels are non-selective cationic channels with permeability to Ca2+ and Na+. Despite their importance, there are currently few studies on TRPC in the periodontal ligament (PDL) and bone cells in the dental field. To provide biological information regarding TRPC in PDL cells and periodontal tissue, we evaluated TRPC channels expression in the osteoblast differentiation of PDL cells and periodontitis-induced tissue. Human PDL cells were cultured in osteogenic differentiation media for 28 days, and the expression of Runx2, osteocalcin (OCN), and TRPC1, 3, 4, and 6 was evaluated by real-time PCR. In ligature-induced periodontitis mice, the alveolar bone and osteoid areas, the osteoclast number, and the expression of Runx2, OCN, TRPC3, and TRPC6 was evaluated by H&E staining, TRAP staining, and immunohistochemistry, respectively.

RESULTS

In the PDL cell differentiation group, TRPC6 expression peaked on day 7 and TRPC3 expression generally increased during differentiation. During the 28 days of periodontitis progression, alveolar bone loss and osteoclast numbers increased compared to the control group during the experimental period and the osteoid area increased from day 14. TRPC6 expression in the periodontitis group increased in the PDL area and in the osteoblasts compared to the control group, whereas TRPC3 expression increased only in the PDL area on days 7 and 28.

CONCLUSIONS

These results indicate changes of TRPC3 and TRPC6 expression in PDL cells that were differentiating into osteoblasts and in periodontitis-induced tissue, suggesting the need for research on the role of TRPC in osteoblast differentiation or periodontitis progression.

Benefits of Antimicrobial Photodynamic Therapy as an Adjunct to Non-Surgical Periodontal Treatment in Smokers with Periodontitis: A Systematic Review and Meta-Analysis

The objective of this study was to analyze evidence of the clinical and microbiological benefits of antimicrobial photodynamic therapy (aPDT) adjunctive to scaling and root planing (SRP) in smokers with periodontitis. Randomized clinical trials (RCTs) were included, through an electronic search in PubMed/MEDLINE, LILACS, Web of Science, and the Cochrane Library for articles published in English until December 2022. The quality of the studies was assessed using the JADAD scale and the risk of bias was estimated using the Cochrane Collaboration assessment tool. Of the 175 relevant articles, eight RCTs were included. Of these, seven reported clinical results and five microbiological results, with a follow-up time of 3–6 months. A meta-analysis was performed for the probing depth (PD) reduction and clinical attachment level (CAL) gain at 3 and 6 months. The weighted mean differences (WMDs) and 95% confidence intervals (CIs) were counted for the PD and CAL. The overall effect for the PD reduction at 3 and 6 months (WMD = −0.80, 95% CI = −1.44 to −0.17, p = 0.01; WMD = −1.35, 95% CI = −2.23 to −0.46, p = 0.003) was in favor of aPDT. The CAL gain (WMD = 0.79, 95% CI = −1.24 to −0.35, p = 0.0005) was statistically significant at 6 months, in favor of aPDT. In these RCTs, aPDT was unable to demonstrate efficacy in reducing the microbial species associated with periodontitis. aPDT as an adjuvant to SRP improves the PD reduction and CAL gain more effectively than only SRP. RCTs are needed to establish standardized protocols with longer follow-up times in order to provide more results on aPDT adjunctive to SRP in smokers with periodontitis.

DNA-aptamer-nanographene oxide as a targeted bio-theragnostic system in antimicrobial photodynamic therapy against Porphyromonas gingivalis

The aim of this study was to design and evaluate the specificity of a targeted bio-theragnostic system based on DNA-aptamer-nanographene oxide (NGO) against Porphyromonas gingivalis during antimicrobial photodynamic therapy (aPDT). Following synthesis and confirmation of NGO, the binding of selected labeled DNA-aptamer to NGO was performed and its hemolytic activity, cytotoxic effect, and release times were evaluated. The specificity of DNA-aptamer-NGO to P. gingivalis was determined. The antimicrobial effect, anti-biofilm potency, and anti-metabolic activity of aPDT were then assessed after the determination of the bacteriostatic and bactericidal concentrations of DNA-aptamer-NGO against P. gingivalis. Eventually, the apoptotic effect and anti-virulence capacity of aPDT based on DNA-aptamer-NGO were investigated. The results showed that NGO with a flaky, scale-like, and layered structure in non-cytotoxic DNA-aptamer-NGO has a continuous release in the weak-acid environment within a period of 240 h. The binding specificity of DNA-aptamer-NGO to P. gingivalis was confirmed by flow cytometry. When irradiated, non-hemolytic DNA-aptamer-NGO were photoactivated, generated ROS, and led to a significant decrease in the cell viability of P. gingivalis (P < 0.05). Also, the data indicated that DNA-aptamer-NGO-mediated aPDT led to a remarkable reduction of biofilms and metabolic activity of P. gingivalis compared to the control group (P < 0.05). In addition, the number of apoptotic cells increased slightly (P > 0.05) and the expression level of genes involved in bacterial biofilm formation and response to oxidative stress changed significantly after exposure to aPDT. It is concluded that aPDT using DNA-aptamer-NGO as a targeted bio-theragnostic system is a promising approach to detect and eliminate P. gingivalis as one of the main bacteria involved in periodontitis in periopathogenic complex in real-time and in situ.