Increased expression of genes after periodontal treatment with photodynamic therapy

Multiple Sessions of Antimicrobial Photodynamic Therapy Improve Periodontal Outcomes in Patients with Down Syndrome: A 12-Month Randomized Clinical Trial

Background/Objectives: Individuals with Down syndrome (DS) often present with severe periodontal disease at a young age. Adjuvant treatments to scaling and root planing (SRP), such as antimicrobial photodynamic therapy (aPDT), may benefit this population. This study evaluated the effectiveness of aPDT as an adjunct to SRP in individuals with DS. A randomized, double-blind, parallel trial was conducted with 37 individuals with DS. Methods: The test group (aPDT; n = 18) received SRP + aPDT, while the control group (C group; n = 19) received SRP only. For aPDT, a red laser (658 nm; 0.1 W; 2229 J/cm2; 40 s sweeping with optical fiber) combined with methylene blue (MB) (100 µg/mL) was applied across repeated sessions (on days 3, 7, and 14). Clinical parameters, such as plaque index (PI), clinical attachment level (CAL), probing depth (PD), and bleeding on probing (BOP), were recorded at baseline and after 3, 6, and 12 months of treatment. Statistical analyses were performed using parametric and non-parametric tests (p < 0.05). Results: Both treatments promoted improvements in all clinical periodontal parameters (p < 0.05). The aPDT group showed a statistically significant reduction in CAL at 3 months (aPDT = 4.58 mm vs. C = 4.72 mm; p < 0.05) and 12 months (aPDT = 4.59 mm vs. C = 4.84 mm; p < 0.05). Conclusions: aPDT improved periodontal health in the long term through a stable gain in attachment.

The Impact of Type 2 Diabetes Mellitus on Non-Surgical Periodontal Treatment: A Non-Randomized Clinical Trial

Background/Objectives: Periodontitis (P), a chronic inflammatory condition that affects the supportive tissues around the teeth, is three to four times more prevalent in individuals with diabetes mellitus (DM), with a direct correlation between its severity and the levels of glycosylated hemoglobin (HbA1c). This study aimed to evaluate the periodontal clinical parameters following non-surgical periodontal treatment (NSPT) in P patients with or without type 2 DM. Methods: Forty patients with P were divided into two groups: Group DM/P and Group P. All the patients were assessed at baseline and at 90 and 180 days after receiving NSPT. The parameters evaluated included the HbA1c level, plaque index (PI), probing pocket depth (PPD), clinical attachment level (CAL), and bleeding on probing (BoP). A statistical analysis was performed with a significance level set at α = 5%. Results: There were significant differences in the HbA1c levels between the DM/P and P groups at baseline, 90, and 180 days, as expected. Importantly, the HbA1c levels did not change after NSPT. Group P showed a significant reduction in both the PI and the BoP values at 90 and 180 days (p < 0.05). In contrast, Group DM/P demonstrated a significant increase in the percentage of sites with a PPD ≥ 5 mm at 180 days (p < 0.05). Additionally, Group P exhibited an increase in sites with a PPD ≤ 4 mm and a decrease in sites with a PPD ≥ 5 mm at both 90 and 180 days (p < 0.05). Conclusions: Our findings suggest that DM may compromise the effectiveness of NSPT, potentially hindering favorable outcomes during the follow-up period.

A mechanistic study on the toluidine blue/ photodynamic therapy inhibition of lipopolysaccharide-induced inflammatory response in rat gingival fibroblasts

The purpose of this research was to investigate the effect of toluidine blue (TB) mediated photodynamic therapy (PDT) on the inhibition of lipopolysaccharide (LPS)-induced inflammation in rat gingival fibroblasts through in vitro experiments. Rat gingival fibroblasts were divided into five groups: (1) control, (2) LPS treatment, (3) laser treatment, (4) TB treatment (1.0 µg/mL), and (5) PDT treatment (TB plus laser irradiation at 320 mW/cm2 for 240 s). After 24 h, cell growth activity was measured using MTT assay. The levels of receptor activator for nuclear factor-κB ligand (RANKL) and osteoprotegerin (OPG) in the cell culture supernatant were measured using enzyme-linked immunosorbent assay (ELISA). Nuclear proteins were extracted and the phosphorylation levels of phosphorylated nuclear factor-κB/p65 (p-p65) and phosphorylated inhibitor of nuclear factor-κB (p-IκBα) were determined using Western Blot. MTT results showed no significant difference in cell viability between the groups (P > 0.05). After LPS induction, OPG expression decreased, RANKL expression increased, and the OPG/RANKL ratio decreased, which was different from the control group (P < 0.05). After PDT treatment, OPG expression increased, RANKL expression decreased (P < 0.05), and the OPG/RANKL ratio increased (P < 0.05). Compared to the control group, there was no significant difference in OPG and RANKL expression or the OPG/RANKL ratio (P > 0.05). The activation of NF-κB was closely related to the phosphorylation levels of p-p65 and p-IκBα. LPS significantly up-regulated p-p65 and p-IκBα expression (P < 0.05), while PDT treatment decreased their phosphorylation levels (P < 0.05). TB-PDT treatment can inhibit NF-κB signaling pathway activation, decrease RANKL and OPG expression, and reduce the OPG/RANKL ratio, thereby reducing inflammation and playing a role in periodontitis treatment.

The use of photodynamic therapy in medical practice

Cancer therapy, especially for tumors near sensitive areas, demands precise treatment. This review explores photodynamic therapy (PDT), a method leveraging photosensitizers (PS), specific wavelength light, and oxygen to target cancer effectively. Recent advancements affirm PDT's efficacy, utilizing ROS generation to induce cancer cell death. With a history spanning over decades, PDT's dynamic evolution has expanded its application across dermatology, oncology, and dentistry. This review aims to dissect PDT's principles, from its inception to contemporary medical applications, highlighting its role in modern cancer treatment strategies.

Antimicrobial photocatalysis using bio-hydrothermally synthesized Zinc oxide nanoparticles in the management of periodontitis: a prospective split-mouth, double-blind, randomized, controlled clinical trial

BACKGROUND

The antimicrobial activity of metallic nanoparticles (NPs) has been confirmed to fight a broad spectrum of microorganisms, through antimicrobial effects that are amplified when these particles are irradiated with light of the proper wavelength. This is the first study to use phytoconjugated Zinc oxide (ZnO) NPs containing traces of active biomolecules derived from Emblica officinalis (E. officinalis) plant extract in antimicrobial photocatalysis (PCT) during non-surgical periodontal therapy.

OBJECTIVES

This study aimed to evaluate the effects of repeated PCT application in the treatment of periodontitis, using a gel containing bio-hydrothermally synthesized ZnO NPs and visible light as an adjunct to scaling and root planing (SRP).

METHODOLOGY

In total, 16 systemically healthy volunteers with stage 3 grade B generalized periodontitis were recruited for this prospective double blind, randomized placebo-controlled trial. After receiving SRP, the subjects received the following interventions in a split-mouth design at baseline, 1 week and 1 month: Group 1 - Placebo gel + Sham PCT; Group 2 - Nano ZnO gel + Sham PCT; Group 3 - Placebo gel + PCT; and Group 4 - Nano ZnO gel + PCT. The site-specific profile of Porphyromonas gingivalis in the subgingival plaque and clinical parameters (Plaque Index, Gingival Index, Gingival Bleeding Index, Probing pocket Depth and Clinical Attachment Level) were assessed at baseline, 1 month and 3 months.

RESULTS

All interventions tested caused participants' clinical and microbiological parameters to generally improve after 3 months. Subjects who received the Nano ZnO gel + PCT combination showed a sustained and progressive improvement in their treatment outcomes, a result that presented statistically significant differences from the outcomes obtained through the remaining interventions, at all time points during the study period.

CONCLUSIONS

The repeated application of PCT using bio-hydrothermally synthesized ZnO NPs can effectively complement SRP in the non-surgical treatment of Periodontitis.

The potential effect of leptin co-administration on photodynamic damage using quail chorioallantoic membrane model

BACKGROUND

The chorioallantoic membrane (CAM) of the Japanese quail is an excellent model for studying photodynamic therapy (PDT) due to its rich vascularization. PDT is used not only in oncological treatment but also in infectious diseases, or psoriasis, where it yields significant advantages. This treatment also has its limitations, such as burning, itching, erythema, redness, swelling, and delayed wound healing. The aim of this study was to analyse the potentially protective properties of the tissue hormone leptin during PDT.

METHODS

Japanese quail embryos incubated ex ovo were used in this experiment. On the 9th day of embryonic development, leptin (5 μg) and photosensitiser hypericin (79 μM) were topically applied, followed by irradiation. The effect of leptin co-administration was evaluated from CAM images and histological structure analysis, histological samples, and qPCR, where the expression of genes involved in angiogenesis, apoptosis, and oxidative stress was monitored.

RESULTS

We observed vascular damage in all experimental groups, the highest damage was found after the application of hypericin without leptin coadministration. Histological analysis confirmed the protective effect of leptin. qPCR analysis presented differences in FREK gene expression, but also in genes involved in oxidative stress like SOD, NRF-1, NRF-2, and GPX7. The application of leptin significantly reduced the expression of apoptosis regulatory proteins CASP3, cytochrome C, and APAF1.

CONCLUSIONS

Our results in the CAM model suggest a possible protective effect of leptin to prevent PDT damage and aid in the subsequent regeneration of target tissues after antimicrobial PDT.

Central Regulatory Role of Cytokines in Periodontitis and Targeting Options

BACKGROUND

Periodontitis is an immune-inflammatory disease that leads to the progressive destruction of bone and connective tissue in the periodontal area. The cytokine network plays a primary role in tissue homeostasis, the recruitment of immune cells to control the pathogenic impact and the regulation of osteoclastic function, thus modulating the intensity and duration of the immune response. This review provides an update on the main cytokines implicated in the pathogenesis and progression of periodontitis and their targeting potential in order to enrich current treatment options.

METHODS

A structured search of bibliographic databases (PubMed, MEDLINE, Scopus) was performed for peer-reviewed cytokine studies focused on periodontitis the last ten years. A qualitative content analysis was performed in screened papers and a critical discussion of main findings is provided.

RESULTS

An altered cytokine profile has been detected in periodontitis patients and the interplay of pro-inflammatory and/or anti-inflammatory cytokines has been associated with disease pathogenesis. Among the most prominent pro-inflammatory cytokines, TNF-α, IL-1β, IL-17, IL-6 and the chemokines CXCL-6, CXCL-8 are overexpressed in periodontitis patients and correlate with disease progression. On the other hand, the anti-inflammatory IL-4 and IL- 11 levels are reduced while IL-12 and IFN-γ expression play a dual role in periodontal disease. Current periodontitis treatment strategies include selective antibiotics, antimicrobial photodynamic therapy and probiotics, which can modulate the cytokine network and when applied in combination with specific anti-cytokine agents can exert additional beneficial effects.

CONCLUSION

It is evident that cytokines play a central regulatory role in the inflammatory process and immune cell response that underlies bone destruction in periodontitis. Specific cytokine targeting should be considered as a complementary therapeutic scheme to current periodontal management.

Effectiveness of Antimicrobial Photodynamic Therapy in the Treatment of Periodontitis: A Systematic Review and Meta-Analysis of In Vivo Human Randomized Controlled Clinical Trials

This systematic review and meta-analysis evaluated antimicrobial photodynamic therapy (aPDT) efficacy in periodontitis. The review protocol was conducted in accordance with PRISMA statements, Cochrane Collaboration recommendations and is registered in PROSPERO (CRD 42020161516). Electronic and hand search strategies were undertaken to gather data on in vivo human RCTs followed by qualitative analysis. Differences in probing pocket depth (PPD) and clinical attachment level (CAL) were calculated with 95% confidence intervals and pooled in random effects model at three and six months. Heterogeneity was analyzed, using Q and I² tests. Publication bias was assessed by visual examination of the funnel plot symmetry. Sixty percent of 31 eligible studies showed a high risk of bias. Meta-analysis on 18 studies showed no additional benefit in split mouth studies in terms of PPD reduction (SMD 0.166; 95% CI −0.278 to 0.611; P = 0.463) and CAL gain (SMD 0.092; 95% CI −0.013 to 0.198; P = 0.088). Similar findings noted for parallel group studies; PPD reduction (SMD 0.076; 95% CI −0.420 to 0.573; P = 0.763) and CAL gain (SMD 0.056; 95% CI −0.408 to 0.552; P = 0.745). Sensitivity analysis minimized heterogeneity for both outcome variables; however, intergroup differences were not statistically significant. Future research should aim for well-designed RCTs in order to determine the effectiveness of aPDT.

Antimicrobial photodynamic therapy effectively reduces Porphyromonas gingivalis infection in gingival fibroblasts and keratinocytes: An in vitro study

BACKGROUND

Porphyromonas gingivalis possess the ability to invade host cells which prevents this pathogen from eradication by conventional periodontal therapy. Recently, antimicrobial photodynamic therapy (aPDT) was introduced to periodontal treatment as a complementary antibacterial method. The aim of this study was to evaluate the effect of toluidine blue-O (TBO) mediated aPDT on the viability of P. gingivalis invading gingival fibroblasts and keratinocytes in an in vitro model of infection.

METHODS

Primary human gingival fibroblasts (PHGF) and telomerase immortalized gingival keratinocytes (TIGK) were infected with Pg ATCC 33277. Two concentrations of TBO (0.01 mg/mL, TBO-c1 and 0.001 mg/mL, TBO-c2) and a non-laser red light source (λ = 630 nm) were applied to treat both cell-adherent/intracellular Pg (the adhesion/invasion model) or exclusively the intracellular bacteria (the intracellular infection model).

RESULTS

The median viability of cell-adherent/intracellular Pg in infected keratinocytes declined from 1.88 × 10⁵ cfu/mL in infected cells treated with TBO without irradiation to 40 cfu/mL upon irradiation for 10 s with TBO-c1. At higher light doses a complete photokilling of P. gingivalis was observed. Pg from exclusively intracellular infection model was also efficiently eradicated as the residual viability dropped from 1.44 × 10⁵ cfu/mL in control samples to 160, 20 and 10 cfu/mL upon irradiation for 10, 20 and 30 s, respectively. In the infected fibroblasts irradiation significantly reduced bacterial viability but did not completely eradicate the intracellular pathogen.

CONCLUSIONS

Antimicrobial PDT is effective in reducing the viability of intracellular periopathogens, however those residing within gingival fibroblasts seems to attenuate the photokilling effectiveness of this method.

Adjunctive laser or antimicrobial photodynamic therapy to non-surgical mechanical instrumentation in patients with untreated periodontitis: A systematic review and meta-analysis

AIM

To compare the adjunctive effects of lasers or antimicrobial photodynamic therapy (aPDT) to non-surgical mechanical instrumentation alone in untreated periodontitis patients.

MATERIALS AND METHODS

Two focused questions were addressed using the Population, Intervention, Comparison and Outcome criteria as follows: in patients with untreated periodontitis, (a) does laser application provide adjunctive effects on probing pocket depth (PPD) changes compared with non-surgical instrumentation alone? and (b) does application of aPDT provide adjunctive effects on PPD changes compared with non-surgical instrumentation alone? Both randomized controlled clinical trials (RCTs) and controlled clinical trials (CCTs) were included. Results of the meta-analysis are expressed as weighted mean differences (WMD) and reported according to the PRISMA guidelines.

RESULTS

Out of 1,202 records, 10 articles for adjunctive laser and 8 for adjunctive aPDT were included. With respect to PPD changes, 1 meta-analysis including 2 articles (total n = 42; split-mouth design) failed to identify a statistically significant difference (WMD = 0.35 mm; 95%CI: -0.04/0.73; p = .08) in favour of adjunctive aPDT (wavelength range 650-700 nm). In terms of adjunctive laser application, a high variability of clinical outcomes at 6 months was noted. Two articles included patient-reported outcomes and 10 reported on the presence/absence of harms/adverse effects.

CONCLUSIONS

Available evidence on adjunctive therapy with lasers and aPDT is limited by (a) the low number of controlled studies and (b) the heterogeneity of study designs. Patient-reported benefits remain to be demonstrated.

The impact of Aggregatibacter actinomycetemcomitans biofilm-derived effectors following antimicrobial photodynamic therapy on cytokine production in human gingival fibroblasts

BACKGROUND

Antimicrobial photodynamic therapy (aPDT) is an effective adjunctive therapeutic modality for the treatment of local infections, including periodontitis and peri-implantitis. After receiving aPDT, microbial cells in the biofilm structure may produce and/ or release soluble biofilm-derived effectors (BDEs), which may affect the biology of the host cells in the community context of their surrounding microenvironment. Given the fact that no study has investigated the role of BDEs following aPDT in the pathogenesis of infectious diseases, the aim of the current study was to determine the effect of BDEs of Aggregatibacter actinomycetemcomitans following exposure to sub-lethal doses of indocyanine green (ICG)-aPDT on human gingival fibroblasts (HGFs) in terms of cytokines produced.

MATERIALS AND METHODS

In this study, we evaluated the effect of biofilm-conditioned medium (BCM) resulting from the treatment of A. actinomycetemcomitans biofilm with a sub-lethal dose of aPDT on cytokines production, including IL-6, IL-8, CXCL10, TGF-β, and bFGF of HGFs using enzyme-linked immunoassays (ELISA). The sensitivity of cytokines to BDEs was determined by micro-titer plates.

RESULTS

The maximal sub-lethal dose of ICG-PDT was 20.15 μM/mL ICG at a fluence of 31.2 J/cm². The BCM of ICG-PDT-treated viable A. actinomycetemcomitans significantly reduced IL-6, IL-8, and CXCL10 levels compared to the BCM of untreated viable A. actinomycetemcomitans (78-, 93-, and 61.6-fold reduction, respectively; all P < 0.01). TGF-β and bFGF were strongly induced by BCM of ICG-PDT treated viable A. actinomycetemcomitans (by 57.7 and 36.1 folds, respectively; both P < 0.05). The BCM of untreated viable A. actinomycetemcomitans degraded most of the CxCL10, TGF-β and bFGF (58.8, 61.5, and 71.6%, respectively) in 24 h, while it degraded 9.3% of IL-6 and 15.1% of IL-8 after 24 h.

CONCLUSION

The results of the current study revealed that a sub-lethal dose of ICG-aPDT through the effect of BCM on HGFs could not only significantly reduce the production of pro-inflammatory cytokines but also promoted their role in periodontal regeneration due to increasing the bFGF level. Altogether, ICG-aPDT, with it's antimicrobial effects reduces inflammation and induces of tissue regeneration resulting from BCM, can be considered an efficient adjunctive therapeutic method for the treatment of local infections.

Impact of photodynamic therapy versus ultrasonic scaler on gingival health during treatment with orthodontic fixed appliances

OBJECTIVES

Poor oral hygiene during treatment with fixed appliances results in plaque accumulation. The presence of bacteria in the gingival crevice triggers an inflammatory reaction in the gingival tissues. The aim of this study was to compare the impact of two preventive treatments, photodynamic therapy (PDT), and ultrasonic scaler (US), on gingival health in patients under fixed orthodontic treatment.

METHODS

Twenty orthodontic patients were randomly allocated to two groups: PDT or US. Each group received seven sessions [days 0, 15, 30, 45, 90 (3-months follow-up), 180 (6-months follow-up), 270 (9-months follow-up)] of experimental interventions, and clinical parameters [Plaque index(PI); gingival index(GI); probing depth(PD)], periodontopathogens [Agreggatibacter actinomycetemcomitans; Porphyromonas gingivalis; Prevotella intermedia; Micromonas micros; Fusobacterium nucleatum; Tannerella forsythia; Campylobacter rectus; Eikenella corrodens; Capnocytopaga sp.] and protein markers [IL-1β;IL-1ra;IL-6;IL-10;TNF-α;FGF-2/FGF basic] were monitored at baseline and at 3, 6, and 9 months. ANOVA, Student's t-test with Bonferroni correction and ANOVA with multiple rank test were used to identify differences between groups (P < 0.05).

RESULTS

Clinical assessments [PI, GI, and PD] yielded no differences (P > 0.05) between groups, which showed a major decrease at the start of the trial. Reductions in total colony forming units (log CFU reduction) were observed with both treatments, although to a greater extent in the PDT group, but with no differences between groups (P > 0.05). Similar reductions in log CFU counts of P. gingivalis, P. intermedia, and F. nucleatum were observed in both groups (P > 0.05). The two groups also showed similar trends for inflammatory mediators with decreased levels of IL-1β, IL-10, and TNF-α, whereas IL-6 and IL-1ra levels remained stable and those of FGF-2 were increased after both interventions, with no differences (P > 0.05) between groups.

CONCLUSION

Both PDT and US methods proved similar effectiveness for the treatment of gingival inflammation induced by fixed orthodontic appliances. Lasers Surg. Med. 51:256-267, 2019. © 2018 Wiley Periodicals, Inc.

Efficacy of photodynamic therapy vs ultrasonic scaler for preventing gingival inflammation and white spot lesions during orthodontic treatment

INTRODUCTION

The complex designs of fixed orthodontic appliances hinder proper access for cleaning, favouring the development of gingival inflammation and white spot lesions around brackets. The aim of this study was to evaluate the effectiveness to avoid these undesirable effects by using two prophylactic methods: Photodynamic Therapy (PDT) and conventional ultrasonic scaler (US), in patients during fixed orthodontic treatment.

MATERIALS AND METHODS

Twenty patients under orthodontic treatment for at least 15 months were randomly divided into two groups: PDT mediated by methylene blue (MB) and US. Both treatments were applied in repeated doses (four times in intervals of 2 weeks in the beginning of the study (T0), with booster doses at 3, 6 and 9 months, T1, T2 and T3, respectively). Periodontal clinical parameters (full-mouth plaque score (FMPS), full-mouth bleeding score (FMBS) and probing depth (PD)) were recorded as well as the International Caries Detection and Assessment System (ICDAS) index. Samples of subgingival plaque and saliva (for determination of 4 periodontopathogens and mutans streptococci, respectively), were collected at T0 and at the follow-ups of T1, T2 and T3.

RESULTS

The evolution of FMPS, FMBS, PD, ICDAS scores as well as the counts of periodontopathogens and salivary mutans streptococci was similar after US or PDT implementation. Greatest periodontal scores reduction took place at T1 for FMBS and PD and at T2 for FMPS. Main microbial reduction took place at T1. ICDAS index began to increase from T2. No statistically significant intergroup differences were observed.

CONCLUSIONS

Additional treatment of PDT or US in repeated doses delayed undesired side effects during fixed orthodontic treatment in young patients with low caries risk and signs of gingival inflammation.

Indocyanine green-mediated photothermal therapy in treatment of chronic periodontitis: A clinico-microbiological study

Background:

Photodynamic therapy (PDT) has developed as an alternative treatment modality in periodontitis patients. Different photosensitizers used over the years have shown contradictory results. Thus, recently indocyanine green (ICG)-mediated photothermal therapy has emerged for the treatment of chronic periodontitis.

Aim:

The present study aimed at comparing and evaluating the effects of photothermal therapy using ICG in the treatment of chronic periodontitis with scaling and root planing (SRP).

Materials and Methods:

This was a randomized, controlled, clinical trial where fifty participants were equally divided into two groups, i.e., control group (SRP) and test group (SRP + photothermal therapy). Clinical parameters were evaluated at baseline and 6-month follow-up. These were plaque index (PI), bleeding on probing (BOP), probing depth (PD), and clinical attachment level (CAL). Microbiological analysis of plaque sample was also done to check for anaerobic mixed flora.

Results:

Significant reduction was seen in PD, CAL, and BOP in the test group as compared to control group after 6 months (P < 0.05). However, intergroup comparison of PI showed nonsignificant results (P > 0.05). Anaerobic culture of plaque samples of test group also revealed a significant reduction of microorganisms in comparison with control group.

Conclusion:

ICG-mediated photothermal therapy can act as an alternative to antimicrobial PDT as an adjunct to SRP in the treatment of chronic periodontitis.

Effects of photodynamic therapy in periodontal treatment: A randomized, controlled clinical trial

AIM

To evaluate the effects of photodynamic therapy (PDT) in the nonsurgical treatment of chronic periodontitis.

MATERIALS AND METHODS

A randomized, single-blind, controlled, parallel-group clinical trial was performed. Sixty patients were enrolled: 20 healthy controls and 40 patients with periodontitis. The 40 patients were randomized for scaling and root planing (SRP) or SRP + PDT. Periodontal (plaque index, probing depth, clinical recession, clinical attachment level, bleeding on probing and gingival crevicular fluid volume, corresponding to 381 versus 428 critical sites), microbiological (Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola, Prevotella intermedia and Campylobacter rectus presence, 18 versus 19 samples) and biochemical (interleukin (IL)-1β, IL-6 and tumour necrosis factor (TNF)-α, receptor activator of nuclear factor-kappaB ligand (RANK-L) and osteoprotegerin (OPG) levels, 18 versus 19 samples) parameters were recorded.

RESULTS

Within each group, significant improvements were found for clinical parameters, though without significant differences between groups. RANK-L was significantly decreased at week 13 in the SRP + PDT group compared with the SRP group. SRP + PDT, but not SRP alone, significantly reduced the abundance of A. actinomycetemcomitans.

CONCLUSIONS

Except for a significant decrease in the pathogenic burden of A. actinomycetemcomitans, coadjuvant PDT resulted in no additional improvement compared with SRP alone in patients diagnosed with moderate-to-advanced chronic periodontitis.

pH influences the biocompatibility of methylene blue solutions

OBJECTIVE

The aim of this study was to investigate the biocompatibility of methylene blue at different pH levels through the method of implantation in subcutaneous tissue.

MATERIALS AND METHODS

Eighty-four sterilized polyethylene tubes were allocated in the subcutaneous tissue of 28 rats, each one receiving four tubes, set into four groups: group tube (G-T)-empty tube, fibrin group (G-F)-tube filled with fibrin sponge, group methylene blue pH 7 (G-MB/pH 7)-tube filled with fibrin sponge soaked by methylene blue (100 μg/ml) at pH 7.0, and group methylene blue pH 1 (G-MB/pH 1)-tube filled with fibrin sponge and soaked by methylene blue (100 μg/ml) at pH 1.0. After 7, 15, and 30 days, seven animals from each group were euthanized, and the tubes involved by the surrounding tissue were removed and fixed with 4% buffered formaldehyde solution. The collected pieces were processed and histological sections (4 μm) were stained with hematoxylin and eosin and analyzed by light microscopy. Scores were assigned to analysis of histopathologic parameters. The results were statistically analyzed by the Kruskal-Wallis test (p ≤ 0.05).

RESULTS

At 7 and 30 days, the G-MB/pH 1 group showed no significant difference in the G-T control group, while G-MB/pH 7 had a significant increase on tissue reaction, also when compared to G-T. At 15 days, there was no statistical difference between the groups.

CONCLUSION

Within the limits of this study, it is concluded that methylene blue at pH 1.0 provides better biocompatibility than at pH 7.0.

A Dual Role for P2X7 Receptor during Porphyromonas gingivalis Infection

Emerging evidence suggests a role for purinergic signaling in the activation of multiprotein intracellular complexes called inflammasomes, which control the release of potent inflammatory cytokines, such as interleukin (IL) -1β and -18. Porphyromonas gingivalis is intimately associated with periodontitis and is currently considered one of the pathogens that can subvert the immune system by limiting the activation of the NLRP3 inflammasome. We recently showed that P. gingivalis can dampen eATP-induced IL-1β secretion by means of its fimbriae in a purinergic P2X7 receptor-dependent manner. Here, we further explore the role of this purinergic receptor during eATP-induced IL-1β processing and secretion by P. gingivalis-infected macrophages. We found that NLRP3 was necessary for eATP-induced IL-1β secretion as well as for caspase 1 activation irrespective of P. gingivalis fimbriae. Additionally, although the secretion of IL-1β from P. gingivalis-infected macrophages was dependent on NLRP3, its adaptor protein ASC, or caspase 1, the cleavage of intracellular pro-IL-1β to the mature form was found to occur independently of NLRP3, its adaptor protein ASC, or caspase 1. Our in vitro findings revealed that P2X7 receptor has a dual role, being critical not only for eATP-induced IL-1β secretion but also for intracellular pro-IL-1β processing. These results were relevant in vivo since P2X7 receptor expression was upregulated in a P. gingivalis oral infection model, and reduced IFN-γ and IL-17 were detected in draining lymph node cells from P2rx7(-/-) mice. Furthermore, we demonstrated that P2X7 receptor and NLRP3 transcription were modulated in human chronic periodontitis. Overall, we conclude that the P2X7 receptor has a role in periodontal immunopathogenesis and suggest that targeting of the P2X7/NLRP3 pathway should be considered in future therapeutic interventions in periodontitis.