Adjunctive effect of antimicrobial photodynamic therapy in induced periodontal disease. Animal study with histomorphometrical, immunohistochemical, and cytokine evaluation

Multiple PDT sessions with chlorin-e6 and LL-37 loaded-nanoemulsion provide limited benefits to periodontitis in rats

BACKGROUND

The combination of photodynamic therapy (PDT) and LL-37 has never been tested in an animal study and our research team background suggests this strategy might be a promising alternative to intensify periodontitis resolution. This study aimed to assess the effects of multiple sessions of PDT with chlorin-e6 conjugated to the antimicrobial peptide LL-37 loaded nanoemulsion, as adjunctive therapy in experimental periodontitis in rats.

METHODS

Experimental periodontitis was induced in 81 rats. After disease establishment, animals were assigned to three groups: SRP (scaling and root planning); SRP + 1PDT, SRP followed by a single PDT session; SRP + 4PDT (n=27), SRP followed by four PDT sessions at 0, 24, 48 and 72h after SRP. Animals were subjected to euthanasia at 7, 14 and 28 days, and samples were submitted to osteoclast quantification, immunological and microtomography analysis.

RESULTS

All treatments resulted in significant periodontal improvements and there was no significant difference between the groups in both local inflammatory response and healing process. Minimal adjunctive effects could be found for the combined therapy in terms of cytokine levels (IL-1β and IL-10), with no statistical significance. However, the number of TRAP-positive osteoclasts per mm of alveolar bone linear surface for the group treated with PDT sessions was significantly lower than those treated with SRP only.

CONCLUSIONS

Multiple PDT sessions with chlorin-e6 and LL-37 nanoemulsion as an adjunct to scaling and root planning reduced the presence of osteoclast in the local site but did not contribute towards bone regeneration and IL-1β and IL-10 levels.

Superhydrophobic Tipped Antimicrobial Photodynamic Therapy Device for the In Vivo Treatment of Periodontitis Using a Wistar Rat Model

Limited options exist for treatment of periodontitis; scaling and root planing (SRP) are not sufficient to eradicate P. gingivalis and the resulting inflammatory disease. Chlorhexidine (CHX), used as an adjuvant to SRP, may reduce bacterial loads but leads to pain and staining, while evidence for its efficacy is lacking. Antibiotics are effective but can lead to drug-resistance. The rising concern of antibiotic resistance limits the future use of this treatment approach. This study evaluates the efficacy of a novel superhydrophobic (SH) antimicrobial photodynamic therapy (aPDT) device as an adjuvant to SRP for the treatment of periodontitis induced in a Wistar rat in vivo model relative to CHX. The SH-aPDT device comprises an SH silicone rubber strip coated with verteporfin photosensitizer (PS), sterilized, and secured onto a tapered plastic optical fiber tip connected to a red diode laser. The superhydrophobic polydimethylsiloxane (PDMS) strips were fabricated by using a novel soluble template method that creates a medical-grade elastomer with hierarchical surface roughness without the use of nanoparticles. Superhydrophobicity minimizes direct contact of the PS-coated surface with bacterial biofilms. Upon insertion of the device tip into the pocket and energizing the laser, the device generates singlet oxygen that effectively targets and eliminates bacteria within the periodontal pocket. SH-aPDT treatment using 125 J/cm2 of red light on three consecutive days reduced P. gingivalis significantly more than SRP-CHX controls (p < 0.05). Clinical parameters significantly improved (p < 0.05), and histology and stereometry results demonstrated SH-aPDT to be the most effective treatment for improving healing and reducing inflammation, with an increase in fibroblast cells and extracellular matrix and a reduction in vascularization, inflammatory cells, and COX-2 expression. The SH-aPDT approach resulted in complete disease clearance assessed 30 days after treatment initiation with significant reduction of the periodontal pocket and re-formation of the junctional epithelium at the enamel-cementum junction. PS isolation on a SH strip minimizes the potential for bacteria to develop resistance, where the treatment may be aided by the oxygen supply retained within the SH surface.

Mesenchymal stem cells surpass the capacity of bone marrow aspirate concentrate for periodontal regeneration

Regenerative approaches using mesenchymal stem cells (MSCs) have been evaluated to promote the complete formation of all missing periodontal tissues, e.g., new cementum, bone, and functional periodontal ligaments. MSCs derived from bone marrow have been applied to bone and periodontal defects in several forms, including bone marrow aspirate concentrate (BMAC) and cultured and isolated bone marrow mesenchymal stem cells (BM-MSCs). This study aimed to evaluate the periodontal regeneration capacity of BMAC and cultured BM-MSCs in the wound healing of fenestration defects in rats. Methodology: BM-MSCs were obtained after bone marrow aspiration of the isogenic iliac crests of rats, followed by cultivation and isolation. Autogenous BMAC was collected and centrifuged immediately before surgery. In 36 rats, fenestration defects were created and treated with suspended BM-MSCs, BMAC or left to spontaneously heal (control) (N=6). Their regenerative potential was assessed by microcomputed tomography (µCT) and histomorphometry, as well as their cell phenotype and functionality by the Luminex assay at 15 and 30 postoperative days. Results: BMAC achieved higher bone volume in 30 days than spontaneous healing (p<0.0001) by enhancing osteoblastic lineage commitment maturation, with higher levels of osteopontin (p=0.0013). Defects filled with cultured BM-MSCs achieved higher mature bone formation in early stages than spontaneous healing and BMAC (p=0.0241 and p=0.0143, respectively). Moreover, significantly more cementum-like tissue formation (p<0.0001) was observed with new insertion of fibers in specimens treated with BM-MSCs within 30 days. Conclusion: Both forms of cell transport, BMAC and BM-MSCs, promoted bone formation. However, early bone formation and maturation were achieved when cultured BM-MSCs were used. Likewise, only cultured BM-MSCs were capable of achieving complete periodontal regeneration with inserted fibers in the new cementum-like tissue.

Dental-Plaque Decontamination around Dental Brackets Using Antimicrobial Photodynamic Therapy: An In Vitro Study

Background: In orthodontic therapy, the enamel around brackets is very susceptible to bacterial-plaque retention, which represents a risk factor for dental tissues. The aim of this study was to evaluate the effect of methylene blue and a chlorophyllin–phycocyanin mixture, used with and without light activation, in contrast with a 2% chlorhexidine solution, on Streptococcus mutans colonies. Methods: Twenty caries-free human extracted teeth were randomized into five groups. A Streptococcus mutans suspension was inoculated on teeth in groups B, C, D, and E (A was the positive-control group). Bacterial colonies from groups C, D, and E (B was the negative-control group) were subjected to photosensitizers and 2% chlorhexidine solution. For groups C and D, a combined therapy consisting of photosensitizer and light activation was performed. The Streptococcus mutans colonies were counted, and smears were examined with an optical microscope. Two methods of statistical analysis, unidirectional analysis of variance and the Tukey–Kramer test, were used to evaluate the results. Results: A statistically significant reduction in bacterial colonies was detected after the combined therapy was applied for groups C and D, but the most marked bacterial reduction was observed for group D, where a laser-activated chlorophyll–phycocyanin mixture was used. Conclusions: Photodynamic therapy in combination with methylene blue or chlorophyllin–phycocyanin mixture sensitizers induces a statistically significant decrease in the number of bacterial colonies.

Erythrosine as a photosensitizer for antimicrobial photodynamic therapy with blue light-emitting diodes - An in vitro study

BACKGROUND

This study aims to test the absorbance of a new composition of erythrosine, its pH, cell viability and potential as a photo sensitizer against Candida albicans when irratiaded with blue light emitting-diode (LED).

METHODS

For pH and absorbance tests, erythrosine was prepared at a concentration of 0.03/ml. The cells of the L929 strain were cultured and the alamarBlue® assay was performed on samples to assess cell viability. For the microbiological essay, the strain of Candida albicans ATCC 90028 was selected. Yeast suspensions were divided into the following groups: control without irradiation or photosensitizer (C), irradiated group without photosensitizer (L), photosensitizer group without irradiation (0), and groups that received photosensitizer and irradiation, called aPDT groups.

RESULTS

Erythrosine had no significant changes in pH and its absorbance was also consistent (≅400 nm). When it came to cell viability, on the first day, the group that was in contact with the dye and irradiated with the LED in minimun power was found to have the higher cell proliferation. On day 3, both irradiated groups (maximum and minimum) showed the highest cell proliferation. In the microbiological essay with C. albicans, aPDT groups started to show microbial reduction after 60 and 90 s of irradiation and when irradiated for 120 s, 6 microbial reduction logs were found.

CONCLUSIONS

The erythrosine in question is a PS, with pH stability, blue light absorbance, cell viability and efficacy against C. albicans. More studies with this PS should be encouraged in order to verify its performance in aPDT.

Effects of infrared light laser therapy in vivo and in vitro periodontitis models

BACKGROUND

This study evaluated the effects of infrared light laser therapy (ILLT) on ligature-induced periodontitis in rats using micro-computed tomography (micro-CT), histology, fibroblast migration, and viability analysis.

METHODS

Forty-eight rats were randomly distributed into three groups: control (no periodontitis), PDC (periodontitis without laser therapy), and PD+L (periodontitis with laser therapy). Periodontitis was induced by ligature placement for 4 weeks. The 12-week-old rats (baseline) were subjected to laser treatment and euthanized 30 days after. After treatment, the mandibular first molars were prepared for micro-CT scanning, and histological sections were assessed as to the cementoenamel junction, alveolar bone crest, and polymorphonuclear (PMN) cell infiltration. In vitro assays were carried out to examine NIH/3T3 fibroblast viability after laser therapy.

RESULTS

Migration and cell viability assays revealed that the ILLT maintained fibroblast cell viability with 4 J/cm² , reaching 100% healing. The control group (at baseline and 30 days) presented a statistically significant difference from the PDC group at 30 days in terms of distance from the cementoenamel junction to the alveolar bone crest (CEJ-ABC). The PD+L group showed a statistically substantial difference from the PDC group at 30 days in terms of trabecular thickness (Tb.Th), degree of anisotropy (DA), and closed porosity percentage (Po%).

CONCLUSION

ILLT seemed to preserve the bone structure in the in vivo periodontitis induction model at 30 days and did not reduce cell viability or increase fibroblast migration in vitro. The ILLT provides positive effects on mandibular bone microstructure.

Aptamers recognizing fibronectin confer improved bioactivity to biomaterials and promote new bone formation in a periodontal defect in rats

The use of alloplastic materials in periodontal regenerative therapies is limited by their incapacity to establish a dynamic dialog with the surrounding milieu. The aim of the present study was to control biomaterial surface bioactivity by introducing aptamers to induce the selective adsorption of fibronectin from blood, thus promoting platelets activation in vitro and bone regeneration in vivo. A hyaluronic acid/polyethyleneglycole-based hydrogel was enriched with aptamers selected for recognizing and binding fibronectin. In vitro, the capacity of constructs to support osteoblast adhesion, as well as platelets aggregation and activation was assessed by chemiluminescence within 24 h. Matrices were then evaluated in a rat periodontal defect to assess their regenerative potential by microcomputed tomography (µCT) and their osteogenic capacity by Luminex assay 5, 15 and 30 d postoperatively. Aptamers were found to confer matrices the capacity of sustaining firm cell adhesion (p = 0.0377) and to promote platelets activation (p = 0.0442). In vivo, aptamers promoted new bone formation 30 d post-operatively (p < 0.001) by enhancing osteoblastic lineage commitment maturation. Aptamers are a viable surface modification, which confers alloplastic materials the potential capacity to orchestrate blood clot formation, thus controlling bone healing.

Topical sodium alendronate combined or not with photodynamic therapy as an adjunct to scaling and root planing: Histochemical and immunohistochemical study in rats

OBJECTIVE

The purpose of this study was to evaluate influence of topical sodium alendronate (ALN), photodynamic therapy (aPDT), or a combination thereof as adjuvant to scaling and root planing (SRP) in the treatment of experimental periodontitis in rats.

BACKGROUND

Therapeutic protocols to control periodontitis progression that aim to equalize bacterial action and load with tissue immune response are well addressed in current scientific research.

METHODS

Experimental periodontitis was induced in 96 rats with a ligature around the mandibular left first molar. After 7 days, ligature was removed and animals were treated according to the following experimental groups (n = 8): control-SRP plus saline solution; ALN-SRP plus ALN; aPDT-SRP plus methylene blue irrigation, followed by low-level laser therapy (LLLT); and ALN/aPDT-SRP plus ALN and methylene blue irrigation followed by LLLT. The animals were euthanized at 7, 15, and 30 days after treatments. Collagen maturation (picrosirius red staining) and immunohistochemical analyses (TRAP, RANKL and osteoprotegerin [OPG]) were performed. Data were submitted to statistical analysis (P < .05).

RESULTS

At 7 days, group ALN presented a significantly higher number of TRAP-positive cells and percentage of immature collagen fibers than group ALN/aPDT, while group ALN/aPDT presented a significantly higher percentage of mature collagen fibers than group ALN. At 30 days, group ALN presented significantly lower percentage of immature collagen fibers and higher percentage of mature collagen fibers than control.

CONCLUSION

It can be concluded that topical use of ALN coadjutant to SRP, alone or combined with aPDT, enhanced collagen maturation and reduced osteoclastogenesis during the healing of experimental periodontitis.

Photodynamic therapy versus systemic antibiotic for the treatment of periodontitis in a rat model

BACKGROUND

To compare the therapeutic effect of photodynamic therapy (PDT) with Toluidine blue O hydrogel versus systemic antibiotic (SA) in treating periodontitis on rats.

METHODS

Thirty-two Wistar rats were divided into four groups and treated differently: Negative control (NC) group, normal rats; positive control (PC) group, rats with periodontitis; SA group, rats with periodontitis treated with systemic antibiotic; PDT group, rats with periodontitis treated with PDT. After treatment, gingival sulcus bacterial load was measured by counting the colony forming units per milliliter (CFU mL^-1 ). The tooth and periodontal tissues were histologically processed to analyze histological and immunohistochemical profile. Gingival samples were obtained to quantify interleukin-1 beta (IL-1β) and tumor necrosis factor-alpha (TNF-α) levels.

RESULTS

Gingival sulcus bacteria load is significantly lower in PDT group compared with the SA group. The histological analysis showed that some extremely effective repair signs of periodontal tissue were presented in PDT group, such as no periodontal pocket, no bone resorption, few inflammatory cells, massive fibroblasts and collagen fibers. Several effective repair signs of periodontal tissue were also observed in SA group, such as shallow periodontal pocket, small amount of inflammatory cells, substantial fibroblasts and collagen fibers. There were lower cyclooxygenase-2, matrix metalloproteinase -8 (MMP-8) and RANK immunolabeling, higher osteoprotegerin immunolabeling in PDT group compared with SA group. The IL-1β and TNF-α levels in PDT group were lower than those in NC group, but higher than those in SA group.

CONCLUSION

PDT was effective to treat experimental periodontitis and was superior to systemic metronidazole as a treatment for periodontitis.

Antimicrobial photodynamic therapy alone or in combination with antibiotic local administration against biofilms of Fusobacterium nucleatum and Porphyromonas gingivalis

Antimicrobial photodynamic therapy (aPDT) kills several planktonic pathogens. However, the susceptibility of biofilm-derived anaerobic bacteria to aPDT is poorly characterized. Here, we evaluated the effect of Photodithazine (PDZ)-mediated aPDT on Fusobacterium nucleatum and Porphyromonas gingivalis biofilms. In addition, aPDT was tested with metronidazole (MTZ) to explore the potential antimicrobial effect of the treatment. The minimum inhibitory concentration (MIC) of MTZ was defined for each bacterial species. Single-species biofilms of each species were grown on polystyrene plates under anaerobic conditions for five days. aPDT was performed by applying PDZ at concentrations of 50, 75 and 100 mg/L, followed by exposure to 50 J/cm² LED light (660 nm) with or without MTZ. aPDT exhibited a significant reduction in bacterial viability at a PDZ concentration of 100 mg/L, with 1.12 log₁₀ and 2.66 log₁₀ reductions for F. nucleatum and P. gingivalis in biofilms, respectively. However, the antimicrobial effect against F. nucleatum was achieved only when aPDT was combined with MTZ at 100× MIC. Regarding P. gingivalis, the combination of PDZ-mediated aPDT at 100 mg/L with MTZ 100× MIC resulted in a 5 log₁₀ reduction in the bacterial population. The potential antimicrobial effects of aPDT in combination with MTZ for both single pathogenic biofilms were confirmed by live/dead staining. These results suggest that localized antibiotic administration may be an adjuvant to aPDT to control F. nucleatum and P. gingivalis biofilms.

Role of the adjunctive antimicrobial photodynamic therapy to periodontal treatment at plasmatic oxidative stress and vascular behavior

BACKGROUND

To evaluate for the first time in vivo the effects of methylene blue (MB) photosensitizer dissolved in ethanol in antimicrobial photodynamic therapy (aPDT) as adjuvant periodontal treatment, at plasmatic oxidative stress and vascular behavior in rat model.

METHODS

Wistar rats were divided into negative control (NC, no periodontitis) and positive control (PC, with periodontitis, without any treatment). The other groups had periodontitis and were treated with scaling and root planing (SRP); SRP+aPDT+MB dissolved in water (aPDT I); SRP+aPDT+MB dissolved in ethanol (aPDT II). The periodontitis was induced by ligature at the mandibular right first molar. At 7/15/30days, rats were euthanized, the plasma was used to determine oxidative stress parameters and gingival tissue for histomorphometric analysis.

RESULTS

PC showed higher thiobarbituric acid reactive substances levels in 7/15/30days. aPDT II was able to block the lipid peroxidation, especially between 15th and 30th days. Glutathione reduced levels were consumed in PC, aPDT I and II groups throughout the experiment. aPDT II increased the vitamin C levels which were restored in this group in the 30th day. aPDT II group showed the highest number of blood vessels.

CONCLUSION

In summary, the aPDT with MB dissolved in ethanol provides better therapeutic responses in periodontitis treatment.

Antimicrobial photodynamic therapy with photosensitizer in ethanol improves oxidative status and gingival collagen in a short-term in periodontitis

BACKGROUND

This study evaluated the antimicrobial photodynamic therapy (aPDT) effects using the methylene blue (MB) in ethanol 20% on systemic oxidative status and collagen content from gingiva of rats with periodontitis.

METHODS

Rats were divided into five experimental groups: NC (negative control; no periodontitis); PC (positive control; periodontitis without any treatment); SRP (periodontitis and scaling and root planing), aPDT I (periodontitis and SRP+aPDT+MB solubilized in water), and aPDT II (periodontitis and SRP+aPDT+MB solubilized in ethanol 20%). After 7days of removal of the ligature, the periodontal treatments were performed. At 7/15/30days, gingival tissue was removed for morphometric analysis. The erythrocytes were used to evaluate systemic oxidative status.

RESULTS

PC group showed higher lipoperoxidation levels at 7/15/30days. aPDT indicated a protective influence in erythrocytes at 15days observed by the elevation in levels of systemic antioxidant defense. aPDT II group was the only one that restored the total collagen area in 15days, and recovered the type I collagen area at the same time point.

CONCLUSIONS

aPDT as an adjunct to the SRP can induce the systemic protective response against oxidative stress periodontitis-induced and recover the gingival collagen, thus promoting the healing periodontal, particularly when the MB is dissolved in ethanol 20%.