Treatment of Experimental Periodontal Disease by Photodynamic Therapy in Rats With Diabetes

Lacticaseibacillus rhamnosus GG Improves Periodontal Bone Repair via Gut-Blood Axis in Hyperlipidemia

Periodontal bone regeneration remains a clinical challenge, and hyperlipidemia can aggravate alveolar bone resorption. Probiotics have recently been reported to improve bone mass. We aimed to determine the role of Lacticaseibacillus rhamnosus GG (LGG) in periodontal bone regeneration improvement within the context of periodontitis with hyperlipidemia. A Sprague Dawley rat model for periodontitis, hyperlipidemia, and periodontal fenestration defect was constructed (n = 36) and administered LGG gavage for 6 wk (the rats were subsequently sacrificed). Fecal microbiota from donor rats 3 wk after LGG gavage was transplanted into recipient rats to evaluate the role of LGG-modulated gut microbiota in periodontal bone regeneration. Regenerated bone mass was detected using micro-computerized tomography and hematoxylin and eosin stain. Gut microbiota was analyzed using 16S ribosomal RNA sequencing. Serum metabolites were detected by liquid chromatography-mass spectrometry (6 wk after LGG gavage). The pro-osteogenic effects of screened serum metabolite were verified in vitro on bone marrow mesenchymal stem cells (BMMSCs). We found that the bone mineral density, bone volume (BV), trabecular bone volume fraction (BV/TV), and trabecular thickness of the regenerated periodontal bone increased after LGG gavage (P < 0.05) but had little effect on oral flora. After LGG gavage, Staphylococcus, Corynebacterium, and Collinsella in the gut of donors were significantly changed, and these differences were maintained in recipients, who also showed increased trabecular thickness of the regenerated periodontal bone (P < 0.05). These key genera were correlated with BV/TV and BV (P < 0.05). In addition, LGG gavage significantly regulated bone-related blood metabolites, of which selenomethionine promoted BMMSC osteogenesis. Notably, selenomethionine was associated with key gut genera (P < 0.05). Collectively, LGG improved periodontal bone regeneration in the context of periodontitis with hyperlipidemia by modulating gut microbiota and increasing pro-osteogenic metabolites in the blood. These results reveal new insights into the use of probiotics to promote periodontal bone regeneration via the gut-blood-bone axis.

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.

Nanotechnology for Dentistry: Prospects and Applications

In the XXI century, application of nanostructures in oral medicine has become common. In oral medicine, using nanostructures for the treatment of dental caries constitutes a great challenge. There are extensive studies on the implementation of nanomaterials to dental composites in order to improve their properties, e.g., their adhesive strength. Moreover, nanostructures are helpful in dental implant applications as well as in maxillofacial surgery for accelerated healing, promoting osseointegration, and others. Dental personal care products are an important part of oral medicine where nanomaterials are increasingly used, e.g., toothpaste for hypersensitivity. Nowadays, nanoparticles such as macrocycles are used in different formulations for early cancer diagnosis in the oral area. Cancer of the oral cavity-human squamous carcinoma-is the sixth leading cause of death. Detection in the early stage offers the best chance at total cure. Along with diagnosis, macrocycles are used for photodynamic mechanism-based treatments, which possess many advantages, such as protecting healthy tissues and producing good cosmetic results. Application of nanostructures in medicine carries potential risks, like long-term influence of toxicity on body, which need to be studied further. The introduction and development of nanotechnologies and nanomaterials are no longer part of a hypothetical future, but an increasingly important element of today's medicine.

Hand instrumentation provides improved tissue response over ultrasonic scaler and substantiates safe dental practice: An in vivo study in rats

OBJECTIVE

The aim of this study was to evaluate the effectiveness of hand debridement (HD) versus ultrasonic dental scaler (UDS) for the treatment of experimental periodontitis (EP) in rats.

MATERIAL AND METHODS

Thirty 3-month-old male rats were used. EP was induced around the mandibular first molars (right and left). Seven days after induction, the treatments with either HD (n = 30) or UDS (n = 30) were randomly performed in each molar. Euthanasia were performed at 7, 15, and 30 days after treatment. Histometric (percentage of bone in the furcation [PBF]), histopathological, and immunohistochemical (for detection of tartrate-resistant acid phosphatase [TRAP] and osteocalcin [OCN]). Parametric data (PBF and TRAP) was analyzed by One-way ANOVA followed by Tukey's post-test. OCN was analyzed by Kruskal-Wallis followed by Student-Newman-Keuls post-test. The level of significance was 5%.

RESULTS

Group HD presented higher PBF and lower TRAP-immunolabeling at 30 days as compared with UDS in the same period (p≤0.05). Group HD presented higher OCN immunolabeling at 30 days as compared with 7 and 15 days (p≤0.05). Persistent and exacerbated inflammatory process was observed in some specimens from group UDS at 30 days, as well as the bone trabeculae presented irregular contour, surrounded by many active osteoclasts.

CONCLUSION

Nonsurgical periodontal therapy with HD resulted in higher PBF and lower expression of TRAP as compared with UDS. Also, HD increased the expression of OCN over time.

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.

Obesity influences the proteome of periodontal ligament tissues following periodontitis induction in rats

BACKGROUND AND OBJECTIVES

Many studies have been conducted to better understand the molecular mechanism involved with periodontitis progression. There has been growing interest in the potential impact of obesity on periodontitis onset and progression, but the mechanisms involved remain to be elucidated. The present study was designed to determine the impact of obesity on experimentally induced periodontitis in rats and identify novel pathways involved.

METHODS

Sixteen Holtzman rats were distributed into two groups (n = 8): ligature-induced periodontitis (P) and obesity plus ligature-induced periodontitis (OP). Obesity was induced by a high-fat diet for 70 days, whereas periodontitis was induced for 20 days, with a cotton thread placed around the upper first molars bilaterally. Alveolar bone loss was measured by microtomographic analysis and histologically by histometry on the hemimaxillae. The protein composition of the periodontal ligament was evaluated by proteomic analysis.

RESULTS

Data analysis (body weight, adipose tissue weight, and blood test) confirmed obesity induction, whereas bone loss was confirmed by micro-CT and histologic analyses. Proteome analysis from the periodontal ligament tissues (PDL) identified 819 proteins, 53 exclusive to the P group, 28 exclusive to the OP group, and 738 commonly expressed. Validation was performed by immunohistochemistry for selected proteins (spondin1, vinculin, and TRAP).

CONCLUSION

Histologically, it was found that obesity did not significantly affect bone loss resulting from periodontitis. However, the present study's findings indicated that obesity affects the proteome of PDL submitted to experimental periodontitis, allowing for identifying potential targets for personalized approaches.

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

OBJECTIVE

To investigate the security and effectiveness of antimicrobial photodynamic therapy (aPDT) with a citric acid-based methylene blue (MB) on the periodontal repair following the treatment of ligature-induced experimental periodontitis (EP) in rats.

MATERIAL AND METHODS

Were used 120 male rats, randomly divided into 4 experimental groups (n = 30): no treatment (NT), SRP alone (SRP), SRP plus aPDT using conventional MB pH 7.0 (aPDT-pH7), SRP plus aPDT using acidic MB pH 1.0 (aPDT-pH1). EP was induced at day 0 by the placement of a ligature around the mandibular left first molars. Ten animals per group/period were euthanized at 14, 22 and 37 days. Histopathological, histometric (percentage of bone in the furcation [PBF]) and immunohistochemical (for tartrate-resistant acid phosphatase [TRAP] and osteocalcin [OCN]) analyses were performed. Data were statistically analyzed.

RESULTS

aPDT-pH1 showed the highest PBF as compared with the other treatments. Collectively, tissues' reaction to both dyes were controlled and healthy for the periodontium. Both aPDT protocols reduced the extent and intensity of the local inflammatory response, reduced the alveolar bone resorption, and promoted a better structural arrangement of the connective tissue as compared with SRP. TRAP expression was downregulated while OCN expression was upregulated by aPDT as compared with SRP alone.

CONCLUSION

Our data implicate that the novel MB pH 1.0 is as safe as the conventional MB for use in aPDT and raises its additional benefit of increasing the amount of alveolar bone in the furcation.

Phototherapy and optical waveguides for the treatment of infection

With rapid emergence of multi-drug resistant microbes, it is imperative to seek alternative means for infection control. Optical waveguides are an auspicious delivery method for precise administration of phototherapy. Studies have shown that phototherapy is promising in fighting against a myriad of infectious pathogens (i.e. viruses, bacteria, fungi, and protozoa) including biofilm-forming species and drug-resistant strains while evading treatment resistance. When administered via optical waveguides, phototherapy can treat both superficial and deep-tissue infections while minimizing off-site effects that afflict conventional phototherapy and pharmacotherapy. Despite great therapeutic potential, exact mechanisms, materials, and fabrication designs to optimize this promising treatment option are underexplored. This review outlines principles and applications of phototherapy and optical waveguides for infection control. Research advances, challenges, and outlook regarding this delivery system are rigorously discussed in a hope to inspire future developments of optical waveguide-mediated phototherapy for the management of infection and beyond.

Influence of the treatment with the antineoplastic agents 5-fluorouracil and cisplatin on the severity of experimental periodontitis in rats

PURPOSE

The determination on how antineoplastic agents interfere on the progression of periodontitis is critical for improvement and even development of novel therapeutic approaches for periodontal management. This study evaluated the influence of chemotherapy with 5-fluorouracil (5-FU) or cisplatin (CIS) on healthy periodontal tissues and on the progression of experimental periodontitis (EP).

METHODS

One hundred forty-four male rats were divided into six groups (n = 24). Each group was treated with physiological saline solution (PSS) 0.9%, 5-FU, or CIS. Experimental periodontitis (EP) was induced by ligature placement. Animals were euthanized at 7, 15, and 30 days after treatment. Data were statistically analyzed (p ≤ 0.05).

RESULTS

The groups with EP and treated with 5-FU or CIS showed lower percentage of bone volume in the furcation region and higher percentage of alveolar bone loss, higher number of TRAP-positive cells, and lower number of PCNA-positive cells when compared group with EP and treated with PSS (p ≤ 0.05). Groups with EP and treated with 5-FU or CIS showed high immunolabelling pattern of RANKL, TNF-α, and IL-1β, moderate of BAX, and low of HIF-1α. Histological analysis showed severe tissue breakdown in the groups with EP and treated with 5-FU or CIS.

CONCLUSIONS

Chemotherapy with antineoplastic agents 5-FU and CIS increased the intensity and duration of the inflammation and compromised tissue repair by reduction in cellular and vascular turnover. The more severe periodontal breakdown was caused by 5-FU.

Indocyanine-mediated antimicrobial photodynamic therapy promotes superior clinical effects in stage III and grade C chronic periodontitis among controlled and uncontrolled diabetes mellitus: A randomized controlled clinical trial

BACKGROUND

The aim of this randomized controlled clinical trial was to evaluate the efficacy of indocyanine-green mediated antimicrobial photodynamic therapy (ICG-aPDT) in the treatment of stage III grade C periodontitis in terms of clinical, microbiological, and immune-inflammatory parameters in patients with well-controlled and poorly-controlled form of type-2 diabetes mellitus (T2DM).

MATERIALS AND METHODS

Subjects with a diagnosis of chronic periodontitis according to the new classification and case definition of periodontitis [probing depth (PD): ≥6 mm, interdental clinical attachment loss (CAL): ≥5 mm and bone loss extending to mid-third of root and beyond (≥3 mm)] were recruited. Subjects were grouped on the basis of well-controlled and poorly-controlled diabetic status. Two subgroups were made according to the treatment modality (RSD versus ICG-aPDT/RSD) in each group. A split-mouth design was used in which one site was designated for control (RSD alone treatment) while the other contralateral site was chosen for test treatment (ICG-aPDT/RSD) in all the patients. Periodontal parameters included the measurement of plaque score (PS), bleeding on probing (BOP), probing depth (PD), clinical attachment level (CAL) and alveolar bone levels (ABL). Identification of Porphyromonas gingivalis and Tannarella forsythia through PCR was executed using species specific primers. Gingival crevicular fluid samples were then analyzed using enzyme-linked immunosorbent assay for the quantification of interleukin (IL)-17 and interferon (IFN)-γ. All the clinical, microbiological, and immunological parameters were assessed using repeated measure ANOVA for intra and inter-group comparisons. The p-value significance was set at 0.05.

RESULTS

The mean age of the 50 patients was 44.7 ± 7.4 years. Systemic parameters suggest no significant change between the times in either HbA1c or serum CRP levels in any of the groups. A statistically significant reduction for BOP was noted for ICG-aPDT group for non-diabetic subjects at 3 months follow up only, while a significant reduction was seen at both 3 months and 6 months among well-controlled and poorly-controlled T2DM subjects (p<0.05). For PD and CAL, a significant improvement was seen for ICG-aPDT group among non-diabetic and well-controlled T2DM subjects at both 3- and 6-months follow up, while a significant reduction was seen at only 3 months among poorly-controlled T2DM subjects. A significant reduction was seen for ICG-aPDT group compared to RSD group for both bacteria in all the three groups at 6 months follow up (p<0.05).

CONCLUSION

ICG-aPDT significantly improved clinical and antimicrobial parameters in well-controlled and poorly-controlled T2DM having stage III and grade C periodontitis. Glycemic status did not have negative impact in the reduction of periodontal parameters in either types of T2DM.

TRIAL REGISTRATION

The present RCT was registered in the clinicaltrials.gov under the identifier: NCT04857346.

Effects of Limosilactobacillus fermentum CCFM1139 on experimental periodontitis in rats

Periodontitis is a polymicrobial inflammatory disease often characterized by the excessive colonization of Porphyromonas gingivalis and Fusobacterium nucleatum, which causes alveolar bone resorption and advanced oral inflammation. This study aimed to evaluate the effect of Limosilactobacillus fermentum CCFM1139 on experimental periodontitis induced following ligature and infection with P. gingivalis and F. nucleatum in vivo. The results showed that L. fermentum CCFM1139 significantly reduced weight loss associated with periodontal inflammation (p < 0.05), while decreasing both the P. gingivalis and F. nucleatum populations within the oral cavity of rats (p < 0.05) and regulating the expression of tumor necrosis factor-alpha, interleukin (IL)-1 beta, and IL-8 in the periodontal tissue (p < 0.05). Microcomputed tomography (micro-CT) and histopathological examination revealed that L. fermentum CCFM1139 supplementation reduced the level of alveolar bone loss and bone porosity and increased bone volume (p < 0.05) in the experimental animals. Furthermore, L. fermentum CCFM1139 exhibited promising effects in preventing the deepening of the periodontal pocket and the increase in the gap between adjacent molars. Thus L. fermentum CCFM1139 was shown to have solid potential as an oral probiotic for protection against periodontitis suggesting that this may be a good candidate in the production of a new functional food for improving periodontitis.

Influence of Doxycycline and InGaAlP Diode Laser at 660 nm Wavelength in the Treatment of Periodontitis Induced in Rats: In Vivo Study

This study evaluated the influence of Doxycycline (DOX) and Low-Intensity Laser (LIL) (InGaAlP diode laser) as scaling and root planing (SRP) adjuvants in the treatment of periodontitis induced in rats. The rats received periodontal disease induction, and after 7 days, the ligature was removed, and the animals were divided into groups/treatments: NT-receive no treatment; SRP-submitted only to SRP; DOX-submitted to SRP and DOX irrigation; LIL-submitted to SRP and LIL irradiation; and DOX + LIL-submitted to SRP treatments, DOX irrigation and LIL irradiation. The animals were sacrificed at 7, 15 and 30 days, and then, the analyses were performed. A lower concentration of Alpha-glycoprotein acid and Complement 3 was observed in the DOX + LIL group compared to all the other groups in all the periods, and for Complement 4 at 15 and 30 days (P < 0.01). A lower bone loss (BL) was observed in the DOX + LIL group compared to all the other groups in all the periods (P < 0.01). It can be concluded that LIL was effective in the reduction of proteins, and its association with DOX was effective in the reduction of proteins and BL, in the treatment of periodontal induction in rats.

Evaluation of antimicrobial photodynamic therapy on wounds infected by Staphylococcus aureus in animal models

BACKGROUND

Antibiotic-resistant Staphylococcus aureus bacteria are one of the expanding challenges. The purpose of current study is to evaluate the antimicrobial effect of photodynamic therapy (aPDT) on wounds infected to Staphylococcus aureus.

METHODS

In this study, 40 six-month-old rats were divided into 4 groups: control, photosensitizer (PS), laser, and aPDT. A full-thickness wound was created on their skin and it was infected by Staphylococcus aureus. For aPDT, the Indocyanine Green (Germany, Nürnberg, A.R.C. Laser, EmunDo) photosensitive agent and laser diod 810 nm (Germany, Nürnberg, A.R.C. Laser) was utilized. The wound healing procedure was monitored every 24 h until the 12th day with photography. The number of the bacteria was counted on the 12th day also. All results were compared using ANOVA and Tukey post hoc tests. Significance level was considered P-Value < 0.05.

RESULTS

The average area of wound reduced in days 5-11th in photosensitizer, laser, and aPDT, respectively. The absolute colonization rate of bacteria in the wounds showed a significant decrease in two groups laser and aPDT compared to the control group. However, the lowest value was for the aPDT.

CONCLUSION

In the conditions of this study, it emerged that aPDT and laser have an antimicrobial effect against antibiotic-resistant bacteria (particularly Staphylococcus aureus) and improve wound healing.

Non-surgical Periodontal Treatment Restored the Gut Microbiota and Intestinal Barrier in Apolipoprotein E-/- Mice With Periodontitis

Periodontitis has been associated with a variety of systematic diseases via affecting gut microbiota. However, the influence of periodontal treatment on intestinal microbiota is not known. Hyperlipidemia can significantly alter gut microbiota structure. It is proposed that the presence of hyperlipidemia can influence the impact of periodontitis on microbiota. This study was conducted to explore the influence of periodontitis and periodontal treatment on the gut microbiota on the basis of hyperlipidemia. Apolipoprotein E^-/-(ApoE^-/-) mice were ligatured to induced periodontitis and non-surgical periodontal treatment was performed for half of them after 4 weeks of ligation. Microbiota communities in the feces collected at 4, 5, 8 weeks after ligation were investigated using next-generation sequencing of 16S rDNA. Bone loss at periodontitis sites were analyzed using micro-computed tomography (Micro-CT). Morphology and mucosal architecture injury of ileum tissue were observed with hematoxylin-eosin staining. The serum lipid levels were assayed. The results showed that β-diversity index in experimental periodontitis group was differed significantly from that of the control group. Significant differences were found in β-diversity between the non-surgical periodontal treatment group and the ligation group. The samples of the non-surgical periodontal treatment group and the control group were clustered together 4 weeks after periodontal treatment. Intestinal villus height and ratio of villus height to crypt depth was found decreased after ligation and restored after non-surgical periodontal treatment. Non-surgical periodontal treatment induced the colonization and prosper of butyrate-producing bacteria Eubacterium, which was absent/not present in the ligation group. We confirmed that periodontitis led to gut microbiota dysbiosis in mice with hyperlipidemia. Non-surgical periodontal treatment had the trend to normalize the gut microbiota and improved the intestinal mucosal barrier impaired by periodontitis in apoE^-/- mice.

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.

Influence of adjuvant therapy with green tea extract in the treatment of experimental periodontitis

AIM

This study evaluated the effects of topical green tea extract solution (GTE) as adjuvant therapy to mechanical debridement for the treatment of experimental periodontitis (EP).

MATERIAL AND METHODS

We used 120 male rats (Rattus norvegicus albinus - Wistar), divided into the following four groups: NEP (sham) (n = 30): no experimental periodontitis (NEP), only simulation of EP by installation and removal of a ligature; EP (n = 30): EP induction by ligature; SRP (n = 30): EP, scaling and root planing (SRP), and irrigation with physiological saline solution; SRP/GT (n = 30): EP, SRP, and irrigation with GTE. Histologic analysis and immunohistochemistry were performed for detection of interleukin (IL)1ß, tumor necrosis factor-alpha (TNF-α), IL-10, and anti-tartrate resistant acid phosphatase (TRAP) in the furcation area. The percentage of bone in the furcation (PBF) was considered the primary variable and evaluated at 14, 22, and 37 days. The data from the histological analysis and the IL- 1B, TNF- A, and IL-10 were submitted to a Kruskal-Wallis variance test and Dunn's posttest (p ≤ 0.05). The histometric data and TRAP were submitted to analysis of variance (ANOVA) and Tukey's posttest (p ≤ 0.05).

RESULTS

The SRP/GT group showed lower inflammatory process, lower immunolabeling pattern of IL-1ß and TNF-α, and greater immunolabeling pattern of IL-10 compared with the EP and SRP groups at 22 days. Fewer TRAP-positive multinucleated osteoclasts were observed in all periods in the SRP/GT group (5.22 ± 0.65; 7.33 ± 0.80; 8.55 ± 1.15) compared with the SRP group (30.67 ± 8.55; 13.22 ± 0.77; 13.87 ± 0.77). Higher PBF was observed in all periods in the SRP/GT group (74.65 ± 7.14; 76.61 ± 5.36; 79.24 ± 3.75) compared with the SRP group (61.60 ± 9.48; 54.84 ± 9.06; 53.25 ± 9.66).

CONCLUSION

GTE adjuvant to SRP reduced inflammation, osteoclastic activity, and alveolar bone loss in EP.

Antimicrobial photodynamic therapy improves the alveolar repair process and prevents the occurrence of osteonecrosis of the jaws after tooth extraction in senile rats treated with zoledronate

This study evaluated the effects of antimicrobial photodynamic therapy (aPDT) in the alveolar repair of rats with major risk factors for bisphosphonate-related osteonecrosis of the jaws (BRONJ). Senile rats received 0.45 ml of vehicle (VEH and VEH/aPDT) or 0.45 ml of zoledronate (ZOL and ZOL/aPDT) every three days for seven weeks. After three weeks of treatment, the first lower left molar was extracted. VEH/aPDT and ZOL/aPDT were submitted to aPDT on the extraction site at 0, 2 and 4 days postoperatively. Euthanasia was performed 28 days postoperatively and the extraction site was evaluated by clinical, histological, histometric, histochemical and immunohistochemical analysis. ZOL showed tissue repair impairment; lower percentage of newly formed bone tissue (NFBT); higher percentage of non-vital bone tissue (NVBT); fewer mature collagen fibers and increased immunolabeling for tumor necrosis factor (TNFα), interleukin (IL)-1β and IL-6. ZOL/aPDT showed clinical and histological characteristics of the extraction site, percentage of NFBT and percentage of mature collagen fiber similar to VEH. Percentage of NVBT and immunolabeling for inflammatory cytokines in ZOL/aPDT was lower than in ZOL. Immunolabeling for tartarato-resistant acid phosphatase (TRAP) was lower in ZOL and ZOL/aPDT. aPDT in the dental extraction site improves tissue repair process and prevents the occurrence of BRONJ-like lesions after tooth extraction.

Adjunctive antimicrobial photodynamic therapy using methylene blue/ethanol formulation in experimental periodontitis in diabetic rats: short-term results

The aim of this study was to evaluate the effect of an MB experimental formulation (ethanol 20%) in aPDT used as an adjuvant to scaling and root planing (SRP) in the periodontal treatment of diabetic rats. Forty male Wistar rats received streptozotocin-intraperitonial injections to induce diabetes. After 14 days, 5 animals were allocated in the non-ligate group (NLG), and 35 animals received ligature at the first right mandibular molar to induce periodontitis. After 7 days, the ligature was removed and the animals were randomized into 4 groups: LG (without treatment, n = 5), SRPG (SRP, n = 10), aPDTW (SRP+aPDT-MB/water, n = 10), and aPDTEt (SRP + aPDT-MB/water/ethanol/carboxymethylcellulose, n = 10). Animals were euthanized after 7 days. Data of bone loss (BL) area, degree of inflammatory cell response, and collagen fibers percentages were statistically analyzed (p < 0.05). Percentage of animals that presented mild and severe inflammatory infiltrate was 10% and 40% for SRPG, 20% and 30% for aPDTW, and 50% and 0% for aPDTEt, respectively. BL area (mm²) was statistically higher in the LG (0.39 ± 0.15) than NLG (0.05 ± 0.02). aPDTEt showed the lowest value of BL (0.08 ± 0.03), followed by aPDTW (0.21 ± 0.15) and SRPG (0.31 ± 0.18). Statistical differences were verified between aPDTEt and SRPG. In relation to the LG, aPDTEt, aPDTW, and SRPG recovered the equivalent 80%, 46%, and 20% of the BL. aPDTEt showed collagen content statistically higher than SRPG and LG, and presented higher mean values than NLG (p > 0.05). Our findings showed aPDTEt presented promising results. aPDT using MB/ethanol can have potential as an adjunctive periodontal treatment in diabetics.

Antimicrobial Photodynamic Therapy: An Effective Alternative Approach to Control Bacterial Infections

Introduction: The purpose of this review was to evaluate the available literature for in vitro and in vivo effectiveness of antimicrobial Photodynamic therapy (aPDT) in the field of bacteriology. Methods: A review of the relevant articles carried out in PubMed and Scopus to determine the efficiency of aPDT used in the reduction of microbial infection. Thirty-one relevant documents retrieved from PubMed, Scopus by inserting "antimicrobial photodynamic therapy" and "bacterial infection" and "photodynamic therapy" keywords. Results: According to different results, aPDT can be used as an adjuvant for the treatment of infectious diseases. The use of photosensitizer methylene blue, toluidine blue O (TBO), indocyanine green with light diode laser centered at (630±10 nm) and (650±10 nm) wavelengths have been shown to have significant results for the treatment of infectious diseases and bactericidal properties Conclusion: These findings suggest that, aPDT can be an efficient method in the treatment of localized and superficial infections.

Effects of the GaAlAs diode laser (780 nm) on the periodontal tissues during orthodontic tooth movement in diabetes rats: histomorphological and immunohistochemical analysis

The purposes of the present study are to assess the effects of the GaAlAs diode laser on the periodontal tissues and to investigate its action on the alveolar bone remodeling process during orthodontic tooth movement in normoglycemic and diabetic rats. Sixty adult male Wistar rats were divided into four groups of 15 rats: normoglycemic (N), diabetic (D), laser-normoglycemic (LN), and laser-diabetic (LD) rats. Diabetes mellitus was induced by a single intravenous injection of 40 mg/kg monohydrated alloxan. The orthodontically moved tooth underwent a force magnitude of 20 cN. The laser irradiation with a continuous emission of a 780-nm wavelength, an output power of 20 mW, and a fiber probe with a spot size of 0.04 cm in diameter and an area of 0.00126 cm² were used. Moreover, an energy density of 640 J/cm² was applied in an exposition time of 40 s. Histomorphological and immunohistochemical analysis was performed. The photobiomodulation (PBM) strongly stimulated the periodontal tissue response, establishing mainly the balance between the bone formation and resorption. Intense inflammatory cell infiltration and extensive loss of bone tissue were mainly found in the D group from 14 days. The number of osteopontin-positive osteocytes was significantly greater in the LN group, followed by the LD, especially at 7 and 14 days, whereas osteoprotegerin-positive osteoblasts were significantly higher in the LN and LD groups than in the N and D groups, respectively, in all periods. The PBM strongly stimulated the alveolar bone remodeling and favored the continuous reorganization of the soft periodontal tissues, leading to the maintenance and integrity of the periodontal microstructure under orthodontic force, especially in uncontrolled diabetic rats.

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.

Low-level laser and antimicrobial photodynamic therapy on experimental periodontitis in rats submitted to chemotherapy by 5-fluorouracil

PURPOSE

The aim of this study was to evaluate the effects of low-level laser therapy (LLLT) and antimicrobial photodynamic therapy (aPDT) as adjuvant to mechanical treatment of experimental periodontitis (EP) in adult rats submitted to 5-fluorouracil (5-FU) chemotherapy.

METHODS

EP was induced through ligature around the left mandibular first molar for 7 days. The ligature was removed and the animals separated into groups: EP, no treatment; 5FU, systemic administration of 5-FU (80 and 40 mg/kg); 5FU/scaling and root planing (SRP), systemic application of 5-FU and SRP; 5FU/SRP/LLLT, systemic application of 5-FU, SRP, and LLLT (660 nm, 0.035 W; 29.4 J/cm²); and 5FU/SRP/aPDT, systemic application of 5-FU, SRP, and aPDT (methylene blue irrigation and LLLT). The animals were euthanized 7, 15, and 30 days after treatments. Histological sections from mandibles were processed for histomorphometric and immunohistochemical analysis (TRAP, RANKL, OPG, TNF-α, IL-6, IL-10). The alveolar bone loss (BL) area in the furcation region of the mandibular first molar was analyzed histometrically.

RESULTS

There was less bone loss in 5FU/SRP/aPDT compared with 5FU at 7 days (p < 0.05). The immunohistochemical analysis showed no significant difference for TRAP and osteoprotegerin, but lower RANKL immunolabeling was observed in the 5FU/SRP/LLLT and 5FU/SRP/aPDT groups compared with the 5FU group at 15 days. There was lower TNF-α and IL-6 immunolabeling in the 5FU/SRP/LLLT and 5FU/SRP/aPDT groups and higher IL-10 immunolabeling in 5FU/SRP/aPDT at 30 days.

CONCLUSION

LLLT and aPDT adjuvant to SRP minimized the effects of 5-FU on periodontal disease. Furthermore, aPDT promoted greater benefits in bone loss control and inflammatory response.

Adjunctive Application of Antimicrobial Photodynamic Therapy in Nonsurgical Periodontal Treatment: A Review of Literature

Periodontal disease is caused by dental plaque biofilms, and the removal of these biofilms from the root surface of teeth plays a central part in its treatment. The conventional treatment for periodontal disease fails to remove periodontal infection in a subset of cases, such as those with complicated root morphology. Adjunctive antimicrobial photodynamic therapy (aPDT) has been proposed as an additional treatment for this infectious disease. Many periodontal pathogenic bacteria are susceptible to low-power lasers in the presence of dyes, such as methylene blue, toluidine blue O, malachite green, and indocyanine green. aPDT uses these light-activated photosensitizer that is incorporated selectively by bacteria and absorbs a low-power laser/light with an appropriate wavelength to induce singlet oxygen and free radicals, which are toxic to bacteria. While this technique has been evaluated by many clinical studies, some systematic reviews and meta-analyses have reported controversial results about the benefits of aPDT for periodontal treatment. In the light of these previous reports, the aim of this review is to provide comprehensive information about aPDT and help extend knowledge of advanced laser therapy.

Sonodynamic effect of hematoporphyrin monomethyl ether on ligature-induced periodontitis in rats

Objectives

The aim of this study was to perform a histological evaluation of sonodynamic therapy (SDT) of hematoporphyrin monomethyl ether (HMME) on artificially induced periodontal disease in rats.

Methods

Submerging ligatures were placed at the subgingival region of the first maxillary molar in rats. Eighty rats were randomly assigned into four groups: group 1 received no treatment; group 2 was subjected to 50 μg/mL HMME alone; group 3 was treated with low-intensity ultrasound alone (1 W/cm²); and group 4 was treated with 50 μg/mL HMME plus ultrasound irradiation (1 MHz, 30 minutes). Ten rats in each group were euthanized at 7 and 15 days, and periodontal tissue samples were taken for histological examination.

Results

The animals treated by SDT showed less bone loss (P<0.05) at all experimental periods than the other three groups. No significant differences were found between the control and HMME groups (P>0.05).

Conclusion

Our results suggest that HMME-mediated SDT can effectively alleviate the periodontal tissue destruction in artificially induced periodontitis in rats. Hence, SDT may have good clinic potential as a noninvasive treatment of periodontal diseases.

Effect of the probiotic Saccharomyces cerevisiae on ligature-induced periodontitis in rats

BACKGROUND AND OBJECTIVE

This study assessed the effects of the local use of Saccharomyces cerevisiae as monotherapy and as an adjuvant to the mechanical treatment of ligature-induced periodontitis in rats.

MATERIAL AND METHODS

Periodontitis was induced in 72 rats via the installation of a ligature around the mandibular first molar. After 7 d, the ligature was removed and the rats were placed in one of the following groups: no treatment (C; n = 18); scaling and root planing (SRP; n = 18); local irrigation with probiotics (PRO; n = 18); and SRP followed by local irrigation with probiotics (SRP/PRO; n = 18). Six rats from each group were killed at 7, 15 and 30 d. The histological characteristics, alveolar bone loss (ABL) and immunolabeling of tumor necrosis factor alpha (TNF-α), interleukin-1beta (IL-1β), interleukin-10 (IL-10) and TRAP on the furcation area of the first molar were assessed.

RESULTS

The PRO group showed features of acceleration of the tissue-repair process during the entire experiment. On day 15, there was less ABL in the SRP/PRO group compared with the C group. There were fewer TRAP-positive cells in the SRP and SRP/PRO groups at 30 d. There was less immunostaining for TNF-α in the PRO and SRP/PRO groups and less immunostaining for IL-1β in the PRO group. However, there was more immunostaining for IL-10 in the PRO group on day 15.

CONCLUSION

Local use of the probiotic did not result in any adverse effects on periodontal tissues. When used as monotherapy or as an adjuvant, the probiotic was effective at controlling periodontitis in rats.

Photodynamic inactivation of biofilm: taking a lightly colored approach to stubborn infection

Microbial biofilms are responsible for a variety of microbial infections in different parts of the body, such as urinary tract infections, catheter infections, middle-ear infections, gingivitis, caries, periodontitis, orthopedic implants, and so on. The microbial biofilm cells have properties and gene expression patterns distinct from planktonic cells, including phenotypic variations in enzymic activity, cell wall composition and surface structure, which increase the resistance to antibiotics and other antimicrobial treatments. There is consequently an urgent need for new approaches to attack biofilm-associated microorganisms, and antimicrobial photodynamic therapy (aPDT) may be a promising candidate. aPDT involves the combination of a nontoxic dye and low-intensity visible light which, in the presence of oxygen, produces cytotoxic reactive oxygen species. It has been demonstrated that many biofilms are susceptible to aPDT, particularly in dental disease. This review will focus on aspects of aPDT that are designed to increase efficiency against biofilms modalities to enhance penetration of photosensitizer into biofilm, and a combination of aPDT with biofilm-disrupting agents.

Light based anti-infectives: ultraviolet C irradiation, photodynamic therapy, blue light, and beyond

Owing to the worldwide increase in antibiotic resistance, researchers are investigating alternative anti-infective strategies to which it is supposed microorganisms will be unable to develop resistance. Prominent among these strategies, is a group of approaches which rely on light to deliver the killing blow. As is well known, ultraviolet light, particularly UVC (200-280 nm), is germicidal, but it has not been much developed as an anti-infective approach until recently, when it was realized that the possible adverse effects to host tissue were relatively minor compared to its high activity in killing pathogens. Photodynamic therapy is the combination of non-toxic photosensitizing dyes with harmless visible light that together produce abundant destructive reactive oxygen species (ROS). Certain cationic dyes or photosensitizers have good specificity for binding to microbial cells while sparing host mammalian cells and can be used for treating many localized infections, both superficial and even deep-seated by using fiber optic delivered light. Many microbial cells are highly sensitive to killing by blue light (400-470 nm) due to accumulation of naturally occurring photosensitizers such as porphyrins and flavins. Near infrared light has also been shown to have antimicrobial effects against certain species. Clinical applications of these technologies include skin, dental, wound, stomach, nasal, toenail and other infections which are amenable to effective light delivery.

Shining light on materials--a self-sterilising revolution

This review focuses on the development of light activated antimicrobial surfaces. These surfaces kill microbes by the action of light and have potential applications in domestic and healthcare settings. The inspiration for the new self-cleaning surfaces originates from photodynamic therapy where light is used to locate and destroy tumours. The first generation photosensitiser molecules, based on a porphyrin ring structure, could be considered as bioinspired and chemically related to chlorophyll. The review looks at developments of both soft polymeric surfaces with either surface bound or impregnated photosensitiser molecules; and hard inorganic surfaces such as modified titanium dioxide. The bacterial kill mechanisms are looked into with both surface types showing primary microbial kill through a radical induced pathway. The hard inorganic surfaces also show low bacterial adherence by means of a light activated photo-wetting of the surfaces meaning that they are "Easy Clean" and wash off microbes uniformly.

Photodynamic therapy induces an immune response against a bacterial pathogen

Photodynamic therapy (PDT) employs the triple combination of photosensitizers, visible light and ambient oxygen. When PDT is used for cancer, it has been observed that both arms of the host immune system (innate and adaptive) are activated. When PDT is used for infectious disease, however, it has been assumed that the direct antimicrobial PDT effect dominates. Murine arthritis caused by methicillin-resistant Staphylococcus aureus in the knee failed to respond to PDT with intravenously injected Photofrin(®). PDT with intra-articular Photofrin produced a biphasic dose response that killed bacteria without destroying host neutrophils. Methylene blue was the optimum photosensitizer to kill bacteria while preserving neutrophils. We used bioluminescence imaging to noninvasively monitor murine bacterial arthritis and found that PDT with intra-articular methylene blue was not only effective, but when used before infection, could protect the mice against a subsequent bacterial challenge. The data emphasize the importance of considering the host immune response in PDT for infectious disease.

Progression of periodontal destruction and the roles of advanced glycation end products in experimental diabetes

BACKGROUND

Progression of diabetes-associated periodontal destruction and the roles of advanced glycation end products (AGEs) are investigated.

METHODS

Diabetes was induced by streptozocotin injection, and periodontitis was induced via silk ligature placement with Porphyromonas gingivalis lipopolysaccharide injection in 64 Sprague-Dawley rats for 7 to 21 days. The quality of alveolar bone and attachment loss (AL) were measured by microcomputed tomography and histology. Destruction profiles were evaluated by histology, histochemistry, immunohistochemistry, and quantitative assessments of inflammatory cells, expression of receptors for AGEs (RAGE), tartrate-resistant acid phosphatase, and proliferating cell nuclear antigen.

RESULTS

Without periodontitis induction, there was no obvious morphologic change in the periodontium, although slight elevations of AGEs and RAGE levels were noted in animals with diabetes. In the group with experimental periodontitis, significant periodontal bone loss was noted in animals both with and without diabetes from day 7, with more progressive bone loss in animals with diabetes during days 14 to 21. Histologically, the disruption of attachment and inflammation were observed from day 7, but subsequently subsided in animals without diabetes. A stronger and more prolonged response with significant AL was observed in animals with diabetes. Stronger inflammation, attenuated and persistent resorptive activity, and weaker proliferating potential were demonstrated by animals with diabetes. AGE deposition and RAGE expression were noted in animals without diabetes but with periodontitis, although levels were considerably elevated in the later stages in animals with diabetes.

CONCLUSIONS

Diabetes augments periodontal destruction by reducing the proliferating capability and activating resorptive activities. Presence of the AGE-RAGE axis without diabetes implies that it is involved in the regulation of inflammation.