Histological evaluation of the safety of toluidine blue-mediated photosensitization to periodontal tissues in mice

Adjunctive antimicrobial photodynamic therapy for treating periodontal and peri-implant diseases

BACKGROUND

Periodontitis and peri-implant diseases are chronic inflammatory conditions occurring in the mouth. Left untreated, periodontitis progressively destroys the tooth-supporting apparatus. Peri-implant diseases occur in tissues around dental implants and are characterised by inflammation in the peri-implant mucosa and subsequent progressive loss of supporting bone. Treatment aims to clean the pockets around teeth or dental implants and prevent damage to surrounding soft tissue and bone, including improvement of oral hygiene, risk factor control (e.g. encouraging cessation of smoking) and surgical interventions. The key aspect of standard non-surgical treatment is the removal of the subgingival biofilm using subgingival instrumentation (SI) (also called scaling and root planing). Antimicrobial photodynamic therapy (aPDT) can be used an adjunctive treatment to SI. It uses light energy to kill micro-organisms that have been treated with a light-absorbing photosensitising agent immediately prior to aPDT.

OBJECTIVES

To assess the effects of SI with adjunctive aPDT versus SI alone or with placebo aPDT for periodontitis and peri-implant diseases in adults.

SEARCH METHODS

We searched the Cochrane Oral Health Trials Register, CENTRAL, MEDLINE, Embase, two other databases and two trials registers up to 14 February 2024.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) (both parallel-group and split-mouth design) in participants with a clinical diagnosis of periodontitis, peri-implantitis or peri-implant disease. We compared the adjunctive use of antimicrobial photodynamic therapy (aPDT), in which aPDT was given after subgingival or submucosal instrumentation (SI), versus SI alone or a combination of SI and a placebo aPDT given during the active or supportive phase of therapy.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methodological procedures, and we used GRADE to assess the certainty of the evidence. We prioritised six outcomes and the measure of change from baseline to six months after treatment: probing pocket depth (PPD), bleeding on probing (BOP), clinical attachment level (CAL), gingival recession (REC), pocket closure and adverse effects related to aPDT. We were also interested in change in bone level (for participants with peri-implantitis), and participant satisfaction and quality of life.

MAIN RESULTS

We included 50 RCTs with 1407 participants. Most studies used a split-mouth study design; only 18 studies used a parallel-group design. Studies were small, ranging from 10 participants to 88. Adjunctive aPDT was given in a single session in 39 studies, in multiple sessions (between two and four sessions) in 11 studies, and one study included both single and multiple sessions. SI was given using hand or power-driven instrumentation (or both), and was carried out prior to adjunctive aPDT. Five studies used placebo aPDT in the control group and we combined these in meta-analyses with studies in which SI alone was used. All studies included high or unclear risks of bias, such as selection bias or performance bias of personnel (when SI was carried out by an operator aware of group allocation). We downgraded the certainty of all the evidence owing to these risks of bias, as well as for unexplained statistical inconsistency in the pooled effect estimates or for imprecision when evidence was derived from very few participants and confidence intervals (CI) indicated possible benefit to both intervention and control groups. Adjunctive aPDT versus SI alone during active treatment of periodontitis (44 studies) We are very uncertain whether adjunctive aPDT during active treatment of periodontitis leads to improvement in any clinical outcomes at six months when compared to SI alone: PPD (mean difference (MD) 0.52 mm, 95% CI 0.31 to 0.74; 15 studies, 452 participants), BOP (MD 5.72%, 95% CI 1.62 to 9.81; 5 studies, 171 studies), CAL (MD 0.44 mm, 95% CI 0.24 to 0.64; 13 studies, 414 participants) and REC (MD 0.00, 95% CI -0.16 to 0.16; 4 studies, 95 participants); very low-certainty evidence. Any apparent differences between adjunctive aPDT and SI alone were not judged to be clinically important. Twenty-four studies (639 participants) observed no adverse effects related to aPDT (moderate-certainty evidence). No studies reported pocket closure at six months, participant satisfaction or quality of life. Adjunctive aPDT versus SI alone during supportive treatment of periodontitis (six studies) We were very uncertain whether adjunctive aPDT during active treatment of periodontitis leads to improvement in any clinical outcomes at six months when compared to SI alone: PPD (MD -0.04 mm, 95% CI -0.19 to 0.10; 3 studies, 125 participants), BOP (MD 4.98%, 95% CI -2.51 to 12.46; 3 studies, 127 participants), CAL (MD 0.07 mm, 95% CI -0.26 to 0.40; 2 studies, 85 participants) and REC (MD -0.20 mm, 95% CI -0.48 to 0.08; 1 study, 24 participants); very low-certainty evidence. These findings were all imprecise and included no clinically important benefits for aPDT. Three studies (134 participants) reported adverse effects: a single participant developed an abscess, though it is not evident whether this was related to aPDT, and two studies observed no adverse effects related to aPDT (moderate-certainty evidence). No studies reported pocket closure at six months, participant satisfaction or quality of life.

AUTHORS' CONCLUSIONS

Because the certainty of the evidence is very low, we cannot be sure if adjunctive aPDT leads to improved clinical outcomes during the active or supportive treatment of periodontitis; moreover, results suggest that any improvements may be too small to be clinically important. The certainty of this evidence can only be increased by the inclusion of large, well-conducted RCTs that are appropriately analysed to account for change in outcome over time or within-participant split-mouth study designs (or both). We found no studies including people with peri-implantitis, and only one study including people with peri-implant mucositis, but this very small study reported no data at six months, warranting more evidence for adjunctive aPDT in this population group.

Effects of Antimicrobial Photosensitizers of Photodynamic Therapy (PDT) to Treat Periodontitis

Antimicrobial photodynamic therapy or aPDT is an alternative therapeutic approach in which lasers and different photosensitizing agents are used to eradicate periodontopathic bacteria in 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.

Light-emitting-diode-based antimicrobial photodynamic therapies in the treatment of periodontitis

The use of light-emitting diode (LED)-based photodynamic therapies in the treatment of periodontitis is increasing because these modalities are effective, safe, and painless. They are not subject to acquired drug resistance or environmental issues and are associated with no complications when used appropriately. These light sources have also been used in combination with pharmacological measures to synergize their effects and optimize therapeutic outcomes. This review focuses on optical devices used in treating periodontitis and delineates the current applications of various methods, including their utility and efficacy. The application of LEDs in periodontology is described.

Repeated irradiation by light-emitting diodes may impede the spontaneous progression of experimental periodontitis: a preclinical study

PURPOSE

We investigated whether repeated irradiation with light-emitting diodes (LEDs) at a combination of 470 nm and 525 nm could suppress the progression of experimental periodontitis.

METHODS

A experimental periodontitis model was established in the second, third, and fourth premolars of the mandible in beagle dogs for 2 months. The spontaneous progression of periodontitis was monitored under the specified treatment regimen for 3 months. During this period, the animals were subjected to treatments of either plaque control only (control) or plaque control with LED application (test) at 2-week intervals. The clinical parameters included the probing pocket depth (PPD), gingival recession (GR), and the clinical attachment level (CAL). Histomorphometric analysis was performed using measurements of the length of the junctional epithelium, connective tissue (CT) zone, and total soft tissue (ST).

RESULTS

There were significant differences in PPD between the control and test groups at baseline and 12 weeks. When the change in PPD was stratified based on time intervals, it was shown that greater differences occurred in the test group, with statistical significance for baseline to 12 weeks, 6 to 12 weeks, and baseline to 6 weeks. There was no significant difference in GR between the control and test groups at any time points. Likewise, no statistically significant differences were found in GR at any time intervals. CAL showed a statistically significant difference between the control and test groups at baseline only, although significant differences in CAL were observed between baseline and 12 weeks and between 6 and 12 weeks. The proportion of CT to ST was smaller for both buccal and lingual areas in the control group than in the test group.

CONCLUSIONS

Repeated LED irradiation with a combination of 470-nm and 525-nm wavelengths may help suppress the progression of periodontal disease.

Efficacy of Adjunctive Antimicrobial Photodynamic Therapy to Mechanical Debridement in the Treatment of Peri-implantitis or Peri-implant Mucositis in Smokers: A Systematic Review and Meta-analysis

This systematic review and meta-analysis aimed to determine whether adjunctive use of antimicrobial photodynamic therapy (a-PDT) in peri-implant diseases improves clinical outcomes in smokers. An electronic search was performed in MEDLINE (through PubMed), Scopus, Cochrane Library, Embase, Web of Science and Google Scholar. The primary outcome measures were bleeding on probing (BOP) and pocket depth (PD). Plaque index (PI) was the secondary outcome. Four RCTs, (188 participants) comprised of 118 cigarette smokers, 38 E-cig smokers and 32 water pipe smokers with follow-up periods ranged from 6 weeks to 6 months were recruited. All trials applied diode laser in one session with wavelengths ranged from 660 to 670 nm. There was a significant difference between mechanical debridement (MD)+a-PDT and MD alone groups in PD (WMD = -1.26 mm, 95% CI: -2.19 to -0.32, P = 0.01) and PI (WMD = -10.60%, 95% CI: -14.46 to -6.74, P < 0.001) at 3-month follow-up. However, a great amount of heterogeneity was observed (PD: χ² = 199.19, I² = 98%, P < 0.001 and PI: χ² = 25.63, I² = 84.4%, P < 0.001). Due to methodological heterogeneity and small number of studies, this systematic review was unable to reach conclusive evidence in regards of adjunctive a-PDT efficacy in improving clinical parameters in smokers.

Antimicrobial Photodynamic Therapy Combined With Antibiotic in the Treatment of Rats With Third-Degree Burns

Cationic porphyrin conjugate, protoporphyrin IX-methyl ethylenediamine derivative (PPIX-MED) has a potent photosensitive antibacterial effect on clinically isolated bacteria, including methicillin-resistant Staphylococcus aureus, (MRSA), Escherichia coli, and Pseudomonas aeruginosa. This study investigated (i) the PPIX-MED-mediated antimicrobial photodynamic effect on these three species in vitro and (ii) the effect of antimicrobial photodynamic therapy (aPDT) combined with the use of an antibiotic on the healing in vivo of third-degree burns of rats with the wounds infected by these bacterial species. PPIX-MED exerted a potent inhibitory effect on the growth of the three bacterial species by producing reactive oxygen species when photoactivated. PPIX-MED-mediated antimicrobial photodynamic therapy (PPIX-MED-aPDT) had high bacterial photoinactivation ability in vitro, with a minimum inhibitory concentration of 15.6 μM PPIX-MED against each of the three types of bacteria and minimum bactericidal concentrations of 31.25 μM against MRSA and E. coli and 62.5 μM against P. aeruginosa. In rats with third-degree burns infected by a mixture of these bacteria, the bactericidal efficiency of PPIX-MED–aPDT-combined-with-antibiotic treatment was higher than that of antibiotic or aPDT treatment alone. This was confirmed by analysis of viable bacterial counts in wound tissue and blood. Enzyme-linked immunosorbent assay revealed that aPDT-combined-with-antibiotic treatment resulted in an obvious reduction in tumor necrosis factor-alpha and interleukin-6 levels compared with the no-treatment control group and the other treatment groups. Immunohistochemistry revealed that the expression of basic fibroblast growth factor and CD31 (a marker of neovascularization), expressed in burn wound tissue was higher in the aPDT-combined-with-antibiotic treatment group than in the other groups. PPIX-MED–aPDT has a promising bactericidal effect both in vitro and in vivo, and PPIX-MED–aPDT-combined-with-antibiotic treatment enhanced the healing of infected third-degree burns in rats.

Repeated application of photodynamic and antibiotic therapy as an adjunct to root surface debridement in patients with grade C and stage III or IV aggressive periodontitis

PURPOSE

To evaluate the efficacy of antimicrobial photodynamic therapy (aPDT) and antimicrobial therapy on clinical and immunological outcomes of periodontal treatment in patients with periodontitis grade C and stage III or IV.

MATERIAL AND METHOD

The patients recruited in the current research fulfil the clinical case definition of periodontitis 'grade C' in terms of onset of the infection and stage III or IV that defines degree and severity of the disease. One-stage full-mouth ultrasonic debridement (UD) was performed and randomly divided in two groups: Group-I - four applications of aPDT, and Group-II - combination of metronidazole (MTZ) and amoxicillin (AMX) 3 tablets each for 7 days. Whole-mouth periodontal parameters were recorded at baseline, 3-, 6-months after completion of treatment. Gingival crevicular fluid samples were obtained for assessment of inflammatory interleukin (IL)-10 and IL-17 at the same time points.

RESULTS

Seventeen healthy patients completed the study protocol and revealed similar clinical findings at baseline. Bleeding scores significantly reduced in group-I at 3 months post treatment (p < 0.05). It could be seen that group-I showed statistically significant reduction of deep periodontal pockets and gain in CAL in patients with GAP at 3 months (p < 0.05). This difference was maintained at 6 months of follow-up (p < 0.001). Group-II was capable of increasing the levels of IL-10 and reducing IL-17 in GCF at both time periods compared to Group-I (p < 0.05). Group-I did not have significant effect on either cytokine levels in GCF (p > 0.05).

CONCLUSION

Antimicrobial photodynamic therapy improved severe deep periodontal pockets. However, the combination of antimicrobial therapy helped in reducing proinflammation in grade C and stage III or IV periodontitis.

Assessment of Photodynamic Therapy and Nanoparticles Effects on Caries Models

AIM:

To assess the antibacterial competence of 650 nm diode laser, Methylene Blue (MB) and Silver Nano-Particles (Ag NPs) on Streptococcus mutans in biofilm-induced caries models.

MATERIAL AND METHODS:

One hundred eighty specimens were prepared and equally divided into 6 groups. One group was untreated (control), and the others were subjected to either MB, laser, Ag NPs, the combination of MB and Laser or MB, laser and Ag NPs.

RESULTS:

Comparison of the log10 mean Colony Forming Units per millilitre (CFU/ml) values of each of the treated 5 groups and the control group was found statistically significant (P-value < 0.05). The combination of MB, laser and Ag NPs recorded the greatest reduction (95.28%). MB alone represented the least capable (74.09%). The efficiency differences among the Ag NPs treated group; the Laser treated group and the combined MB/Laser treated group were found statistically insignificant.

CONCLUSION:

The combination of MB, 650 nm diode laser and Ag NPs may be among the highly effective modern antimicrobial therapeutics in dentistry.

Effectiveness of erythrosine-mediated photodynamic antimicrobial chemotherapy on dental plaque aerobic microorganisms: A randomized controlled trial

Background:

Dental plaque is one of the predominant causes of major oral diseases. Although mechanical and chemical methods are extensively followed to control the development of plaque, plaque-related diseases still persist. Therefore, this necessitates for alternative measures of plaque control, one such alternative is photodynamic antimicrobial chemotherapy (PACT).

Materials and Methods:

Split mouth randomized clinical trial (CTRI/2017/03/008239) was conducted on 30 participants who reported to the hospital. Participants were asked to rinse their mouth for 1 min using 10 ml of 25 μM erythrosine solutions. Same tooth on both quadrants of the same jaw are selected as the test and control. Intervention used was halogen-based composite curing light with wavelength of 500–590 nm. Plaque sample from the control tooth and test tooth was collected before and after exposure, respectively, and sent to microbiological laboratory for colony count.

Results:

Logarithmic mean and standard deviation of control group with 10² dilutions of aerobic microbial count were found to be 5.34 ± 0.94, and for experimental group, it was 4.47 ± 1.37. The statistical difference between mean CFU values between aerobic bacterial counts was significant (P = 0.006).

Conclusions:

Erythrosine-mediated PACT reduces the extent of dental plaque microbial count and has a potential preventive and therapeutic use in day-to-day life and dental clinics.

Novel Broad-Spectrum Antimicrobial Photoinactivation of In Situ Oral Biofilms by Visible Light plus Water-Filtered Infrared A

Antimicrobial photodynamic therapy (APDT) has gained increased attention as an alternative treatment approach in various medical fields. However, the effect of APDT using visible light plus water-filtered infrared A (VIS + wIRA) on oral biofilms remains unexplored. For this purpose, initial and mature oral biofilms were obtained in situ; six healthy subjects wore individual upper jaw acrylic devices with bovine enamel slabs attached to their proximal sites for 2 h or 3 days. The biofilms were incubated with 100 μg ml(-1) toluidine blue O (TB) or chlorin e6 (Ce6) and irradiated with VIS + wIRA with an energy density of 200 mW cm(-2) for 5 min. After cultivation, the CFU of half of the treated biofilm samples were quantified, whereas following live/dead staining, the other half of the samples were monitored by confocal laser scanning microscopy (CLSM). TB- and Ce6-mediated APDT yielded a significant decrease of up to 3.8 and 5.7 log10 CFU for initial and mature oral biofilms, respectively. Quantification of the stained photoinactivated microorganisms confirmed these results. Overall, CLSM revealed the diffusion of the tested photosensitizers into the deepest biofilm layers after exposure to APDT. In particular, Ce6-aided APDT presented elevated permeability and higher effectiveness in eradicating 89.62% of biofilm bacteria compared to TB-aided APDT (82.25%) after 3 days. In conclusion, antimicrobial photoinactivation using VIS + wIRA proved highly potent in eradicating oral biofilms. Since APDT excludes the development of microbial resistance, it could supplement the pharmaceutical treatment of periodontitis or peri-implantitis.

In vitro effectiveness of antimicrobial photodynamic therapy (APDT) using a 660 nm laser and malachite green dye in Staphylococcus aureus biofilms arranged on compact and cancellous bone specimens

The aim of this study was to evaluate the in vitro effectiveness of antimicrobial photodynamic therapy (APDT) using a 660 nm visible laser combined with malachite green (MG) dye in the inactivation of Staphylococcus aureus (ATCC 25923) biofilms formed within compact and cancellous bone specimens. Specimens of 80 compact bones and 80 cancellous bones were contaminated with a standard suspension of S. aureus and incubated for 14 days at 37 °C to allow for the formation of biofilms. The specimens were divided into the following groups (n = 10) according to the treatment conditions: PS-L - (control - no treatment), PS+L - (only MG for 5 min), PS-L + 90 (only laser irradiation for 90 s), PS-L + 180 (only laser irradiation for 180 s), PS-L + 300 (only laser irradiation for 300 s), APDT90 (APDT for 90 s), APDT180 (APDT for 180 s), and APDT300 (APDT for 300 s). The findings were statistically analyzed using an ANOVA 5%. All of the experimental groups were significantly different from the control group for both the compact and cancellous bone specimens. The compact bone specimens that received APDT treatment (for either 90, 180, or 300 s) showed reductions in the log10 CFU/ml of S. aureus by a magnitude of 4 log10. Cancellous bone specimens treated with 300 s of APDT showed the highest efficacy, and these specimens had a reduction in S. aureus CFU/ml by a factor of 3 log10. APDT treatment using these proposed parameters in combination with MG was effective at inactivating S. aureus biofilms in compact and cancellous bone specimens.

In vitro toxicity of photodynamic antimicrobial chemotherapy on human keratinocytes proliferation

This in vitro experimental study has been designed to assess the effects of photodynamic antimicrobial chemotherapy (PACT) on human keratinocytes proliferation. Human keratinocytes (HaCaT) monolayers (∼0.5 cm(2)) have been irradiated with 635 nm red laser light with a fluence of 82.5 or 112.5 J/cm(2) in the absence or presence of toluidine (TB). Cell proliferation, monolayer area coverage, cytokeratin 5 (K5) and filaggrin (Fil) expression, and metalloproteinase (MMP)-2 and MMP-9 activity were measured after 72 h from laser irradiation. HaCaT proliferation was reduced by TB staining. Cell exposure to both low- and high-fluence laser irradiation in both presence and absence of TB staining reduced their proliferation and monolayer area extension. Moreover both laser treatments were able to reduce K5 and Fil expression and MMP-9 production in keratinocytes not treated with TB. These data indicate that PACT could exert toxic effects on normal proliferating keratinocytes present around parodontal pockets. The observed reduced cell proliferation along with a reduced production of enzymes involved in wound healing could alter the clinical outcome of the patients treated with PACT.

Effect of photodynamic therapy, diode laser, and deep scaling on cytokine and acute-phase protein levels in gingival crevicular fluid of residual periodontal pockets

BACKGROUND

There is an ongoing controversy on the benefits of treatment protocols, including dental lasers and photodynamic therapy (PDT). The purpose of this study is to compare the local biologic effects of PDT, diode soft laser (DSL) therapy, and conventional deep scaling and root planing (SRP) in residual pockets.

METHODS

Thirty-two individuals were included based on a history of previous treatment for periodontitis and the persistence of sites with probing depths >4 mm and bleeding on probing. Residual pockets were debrided with an ultrasonic device and then randomly assigned either to PDT, DSL, or SRP. Gingival crevicular fluid was collected before treatment, after 14 days, and at 2 and 6 months. Levels of 13 cytokines and nine acute-phase proteins were measured using a bead-based multiplexing analysis system.

RESULTS

Treatment with PDT, DSL, or SRP led to significant changes in several cytokines and acute-phase proteins: Compared with baseline, levels of interleukin-17, basic fibroblast growth factor, granulocyte colony-stimulating factor, granulocyte macrophage colony-stimulating factor, and macrophage inflammatory protein 1-α were lower 14 days and 2 months after treatment. Except for granulocyte colony-stimulating factor, these differences remained significant throughout the observation period. The levels of five acute-phase proteins (α-2 macroglobulin, haptoglobin, serum amyloid P, procalcitonin, and tissue plasminogen activator) were significantly higher at 6 months than at baseline. No significant differences were observed among the three treatment modalities at any time point for any biochemical parameter.

CONCLUSIONS

Levels of several cytokines and acute-phase proteins significantly changed after treatment regardless of treatment modality. There was no evidence for a specific DSL- or PDT-enhanced expression of inflammatory mediators.

Histomorphometric and microbiological assessment of photodynamic therapy as an adjuvant treatment for periodontitis: a short-term evaluation of inflammatory periodontal conditions and bacterial reduction in a rat model

OBJECTIVE

The aim of this study was to investigate the short-term effects of photodynamic therapy (PDT) in periodontal tissue when it is used as an adjuvant treatment for periodontitis.

BACKGROUND DATA

PDT has been used as an adjuvant in the combat of local infections, such as periodontitis, and combines a photosensitizer (PS) with a light source to induce reactive oxygen species (ROS) and kill microbial cells.

METHODS

Fifty healthy male rats were used in this study. Periodontitis was induced by placing a cotton ligature around the upper left second molar in a subgingival position. Posterior maxillas were removed and histologically prepared with hematoxylin & eosin (H&E) staining techniques. PDT was performed with a diode laser (λ=660 nm) with an output power of 100 mW. Methylene blue aqueous solution (100 μM) was used as the PS while control group used phosphate buffered saline (PBS). Collagen organization, inflammatory infiltrate, and bone loss were evaluated. Bacterial samples were collected before and immediately after treatment to determine bacterial reduction.

RESULTS

The experimental group that was treated with PDT presented better periodontal healing, as measured by collagen organization, inflammatory infiltrate, and bone loss. Significant bacterial reduction was achieved following treatment with or without PDT compared to control, with a higher microbial reduction observed in the PDT group.

CONCLUSIONS

PDT used as an adjuvant treatment showed effective short-term control of periodontitis infection.

Bactericidal effects of a high-power, red light-emitting diode on two periodontopathic bacteria in antimicrobial photodynamic therapy in vitro

AIM

  Light-emitting diodes have been investigated as new light activators for photodynamic therapy. We investigated the bactericidal effects of high-power, red light-emitting diodes on two periodontopathic bacteria in vitro.

METHODS

  A light-emitting diode (intensity: 1100 mW/cm(2) , peak wavelength: 650 nm) was used to irradiate a bacterial solution for either 10 or 20 s. Bacterial solutions (Porphyromonas gingivalis or Aggregatibacter actinomycetemcomitans) at a concentration of 2.5 × 10(6) c.f.u./mL were mixed with an equal volume of either methylene blue or toluidine blue O (0-20 μg/mL) and added to titer plate wells. The plate wells were irradiated with red light-emitting diode light from a distance of 22 or 40 mm. The contents were diluted, and 50 μL was smeared onto blood agar plates. After 1 week of culturing, bacterial c.f.u. were counted.

RESULTS

  The light-emitting diode energy density was estimated to be approximately 4 and 8 J/cm(2) after 10 and 20 s of irradiation, respectively. Red light-emitting diode irradiation for 10 s from a distance of 22 mm, combined with methylene blue at concentrations >10 μg/mL, completely killed Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans.

CONCLUSION

  High-power, red light-emitting diode irradiation with a low concentration of dye showed effective bactericidal effects against two periodontopathic bacteria.

Effects of toluidine blue-mediated photodynamic therapy on periopathogens and periodontal biofilm: in vitro evaluation

Photodynamic therapy (PDT) is a selective modality of killing targeted cells, mostly known for its application in neoplasms. PDT can be considered to be an alternative method for the elimination of periodontal bacteria from the pocket without harms for the resident tissues. Therefore, PDT may replace systemic antibiotics and enhance the effect of mechanical treatments of periodontal defects. This effort focused on the in vitro sensitization of periopathogens (Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Fusobacterium nucleatum and Prevotella intermedia ) Toluidine Blue mediated and on the use of a Diode laser emitting source. The objective of this research was to evaluate the bactericidal in vitro effect of laser diodes 830 nm (as the light source) after photosensitization with Toluidine Blue (TBO) on the following periopathogenic bacteria: Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Fusobacterium nucleatum and Prevotella intermedia. After evaluating the effect on the single bacterial strain, the ability of Diode Laser to disrupt the structure of biofilms produced by A. actinomycetemcomitans after photosensitization with TBO was also analyzed. The study suggests that the association of TBO and diode laser light 830 nm is effective for the killing of bacteria strains and determines the photoinactivation of Aggregatibacter biofilms. In summary, photodynamic therapy has effectively shown its capabilities and, therefore, it can be considered a valid alternative approach to antimicrobial therapy of periodontitis.

Impact of photodynamic therapy on inflammatory cells during human chronic periodontitis

The aim of this study was to evaluate the effects of the photodynamic therapy (PDT) on the inflammatory infiltrate and on the collagen network organization in human advanced chronic periodontitis. Two different drug delivery systems (DDS) were tested (liposomes and nanoemulsions) to determine if the effects of PDT could differ according to the DDS used. Sixteen patients presenting two teeth with chronic advanced periodontitis and important tooth mobility with clinical indication of extraction were included in the group liposomes (group L, n=8) or in the group nanoemulsions (group N, n=8) in order to compare the effects of each DDS. Seven days before extractions one tooth of each patient was treated with PDT using phthalocyanine derivatives as photosensitizers and the contralateral tooth was taken as control. In group L the density of gingival collagen fibers (66±19%) was significantly increased (p<0.02) when compared to controls (35±21%). Concerning the antigen-presenting cells, PDT had differential effects depending on the drug delivery system; the number of macrophages was significantly decreased (p<0.05) in group L while the number of Langerhans cells was significantly decreased in group N (p<0.02). These findings demonstrate that PDT presents an impact on gingival inflammatory phenomenon during chronic periodontitis and leads to a specific decrease of antigen-presenting cells populations according to the drug delivery system used.

Laser phototherapy in the treatment of periodontal disease. A review

Many studies in the literature address the effect of low-power lasers in the management of pathologies related to periodontal tissues. Due to the lack of standardized information and the absence of a consensus, this review presents the current status of laser phototherapy (LPT) in periodontics and discusses its benefits and limits in the treatment of periodontal disease. The literature was searched for reviews and original research articles relating to LPT and periodontal disease. The articles were selected using either electronic search engines or manual tracing of the references cited in key papers. The literature search retrieved references on wound and bone healing, analgesia, hypersensitivity, inflammatory process and antimicrobial photodynamic therapy. Each topic is individually addressed in this review. The current literature suggests that LPT is effective in modulating different periodontal disease aspects in vitro, in animals, and in simple clinical models. Further development of this therapy is now dependent on new clinical trials with more complex study designs.

Toluidine blue-mediated photodynamic therapy of oral wound infections in rats

The purpose of this study was to examine the effect of toluidine blue (TB)-mediated photodynamic therapy (PDT) on oral wound infections in rats. The study called for a combination treatment of a 1mg/ml solution of TB with a red light at three intensity settings of 12 J/cm(2), 24 J/cm(2) and 48 J/cm(2). In the group that was given the highest light dose of 48 J/cm(2), an average kill rate of approximately 97% was achieved. A lesser killing effect was achieved in the group that was subjected to the lowest light dose of 12 J/cm(2), where an average of approximately 25% of the bacteria survived. After PDT, the lesions were allowed to develop, and the peak size of the lesions was larger in the control group than in the test groups, especially for the 48 J/cm(2) group. We also observed that in the 24 J/cm(2) and 48 J/cm(2) groups the lesions were of significantly smaller size. Our study demonstrated that combined TB-PDT therapy can successfully treat oral wound infections in rats. These promising results recommend the use of this treatment as a possible alternative to topical anti-microbials in future clinical applications.

Capacity of photodynamic therapy for microbial reduction in periodontal pockets

Practitioners are not successful in implemented treatments due to the great difficulty in completely removing bacterial deposits and their endotoxins. This study aimed to evaluate the capacity of photodynamic therapy to reduce the numbers of viable bacteria in periodontal pockets. Microbiological samples were collected before and after scaling and after photodynamic therapy. Photodynamic therapy was performed through the insertion of the photosensitizer toluidine blue and Endo PTC into the pocket for 3 min, followed by photosensitization with low-intensity diode of 4 J/cm(2). The results (log(10)) were submitted to a descriptive analysis and a t-test. A reduction of 81.24% in the numbers of bacteria after scaling was observed, as well as 95.90% after photodynamic therapy (P < 0.01). Photodynamic therapy is indicated as an adjuvant treatment to reduce the numbers of viable bacteria in periodontal diseases.