Efficacy and safety of a therapeutic apparatus using hydrogen peroxide photolysis to treat dental and periodontal infectious diseases

Inhibition of tooth demineralization caused by Streptococcus mutans biofilm via antimicrobial treatment using hydrogen peroxide photolysis

OBJECTIVES

An antimicrobial technique utilizing hydroxyl radicals generated by the photolysis of 3% H₂O₂ has been developed recently. The present study aimed to evaluate the effect of H₂O₂ photolysis treatment on tooth demineralization caused by Streptococcus mutans biofilm.

MATERIALS AND METHODS

To induce tooth demineralization, S. mutans biofilm was allowed to form on the maxillary first molars collected from Wistar rats via 24-h culturing. The samples were immersed in 3% H₂O₂ and irradiated with 365-nm LED (H₂O₂ photolysis treatment). Viable bacterial counts in the biofilm were evaluated immediately after treatment and after an additional 30-h culturing by colony counting. The acidogenicity of the biofilm, re-established 30 h after treatment, was assessed by measuring the pH. The effect of H₂O₂ photolysis treatment on tooth demineralization was assessed by measuring the depth of the radiolucent layer in micro-CT images.

RESULTS

H₂O₂ photolysis significantly reduced viable bacterial counts in the biofilm to 3.7 log colony forming units (CFU)/sample, while the untreated group had 7.9 log CFU/sample. The pH of the biofilm re-established after treatment (6.6) was higher than that of the untreated group (5.3). In line with the pH measurement, the treatment group had a significantly lower depth of radiolucent layer in dentin than the untreated group.

CONCLUSIONS

H₂O₂ photolysis treatment was effective not only in killing the biofilm-forming S. mutans but also in lowering the acidogenicity of the biofilm. Thus, this technique could inhibit tooth demineralization.

CLINICAL RELEVANCE

H₂O₂ photolysis can be applicable as a new dental caries treatment.

The In Vitro Effect of Laser Irradiation (Er:YAG and CO2) and Chemical Reagents (Hydrogen Peroxide, Sodium Hypochlorite, Chlorhexidine, or Sodium Fluoride) Alone or in Combination on Reducing Root Caries Bacteria

(1) Lasers have been used for the treatment of dentinal hypersensitivity and bacterial reductions in periodontology. The purpose of this in vitro study was to evaluate the effect of Carbon Dioxide (CO₂) and Erbium-doped Yttrium Aluminum Garnet (Er:YAG) lasers with chlorhexidine (CHX), hydrogen peroxide (H₂O₂), sodium hypochlorite (NaOCl), or sodium fluoride (NaF) on the viability of oral bacteria associated with root caries. (2) Streptococcus mutans, Streptococcus sanguinis, and Enterococcus faecalis were grown in Brain Heart Infusion (BHI) broth, diluted to an OD660 of 0.5, and treated with antiseptics with or without simultaneous irradiation with the Er:YAG and CO₂ lasers for 30 s repeated three times. The treatment groups consisted of 1: no treatment, 2: 0.5% H₂O₂ alone, 3: 0.5% NaOCl alone, 4: 0.12% CHX alone, 5: 2% NaF alone, 6: laser alone, 7: laser with 0.5% H₂O₂, 8: laser with 0.5% NaOCl, 9: laser with 0.12% CHX, and 10: laser with 2% NaF for both lasers. The microbial viability was determined through plating and viable colonies were counted, converted into CFU/mL, and transformed into log form. The statistical analysis was performed using a two-tailed paired t-test. (3) The use of CO₂ and Er:YAG lasers alone failed to show statistically significant antibacterial activity against any of the bacteria. The only effective monotreatment was CHX for S. mutans. The combined treatment of 0.5% NaOCl with Er:YAG produced the greatest reduction in overall viability. (4) The combination of the Er:YAG laser with 0.5% NaOCl resulted in the largest reduction in bacterial survival when compared to monotherapies with antimicrobial solutions or lasers.

Application of Reactive Oxygen Species in Dental Treatment

Reactive oxygen species (ROS) and free radicals, which have been implicated in inflammation, pain, carcinogenesis, and aging, are actually used in dental treatments such as tooth bleaching and composite resin polymerization. Recently, numerous studies have investigated the application of ROS in the medical and dental fields. In previous studies, ROS were generated intentionally through pathways such as photolysis, photocatalytic methods, and photodynamic therapy, which are used in the medical field to target cancer. In the field of dentistry, generated ROS are applied mainly for periodontal treatment and sterilization of the root canal, and its effectiveness as an antibacterial photodynamic therapy has been widely reported.. Given this background, the present article aimed to review the basic effects of ROS in dental medicine, especially endodontic therapy, and to discuss future applications of ROS.

Oral bacterial decontamination using an innovative prototype for photocatalytic disinfection

OBJECTIVES

The aim of this study was to evaluate the effectiveness of a prototype photocatalytic device for bacterial decontaminations of the oral cavity.

METHODS

Sixty-four subjects (18-65) were selected and randomly assigned to eight groups (n = 8), according to oral disinfection protocol: (G1): distilled water (control); (G2): 1.5% hydrogen peroxide (HP); (G3): 3.0% HP; (G4): 0.12% chlorhexidine (CHX); (G5): Germinator; (G6): 1.5% HP + Germinator; (G7): 3.0%HP + Germinator; (G8): 0.12% CHX + Germinator. Stimulated saliva was collected before and after a 3-min mouthwash and/or Germinator application. The patients were kept relaxed and retained saliva 5-10 min, spitting out into the tube for 3 min. The percentage bacterial reduction was checked by counting the colony-forming units (CFUs) after culturing on blood agar plates. Data were subjected to one-way ANOVA followed by Tukey's post hoc test (α = 5%) for statistical significance.

RESULTS

The highest bacterial reduction was observed in groups 3 (3.0% HP), 6 (1.5% HP + Germinator), and 7 (3.0% + Germinator), with no statistically significant difference between them (p > 0.05). Groups 6 (1.5% HP + Germinator) and 8 (0.12% CHX + Germinator) showed higher bacterial reduction than groups 2 (1.5% HP) and 4 (0.12% CHX) (p < 0.05). Finally, group 5 (Germinator) showed higher bacterial reduction than control group (DW) and group 4 (0.12% CHX) (p < 0.05).

CONCLUSIONS

The photocatalytic disinfection was effective against oral bacteria and improved the antimicrobial action of 1.5% HP and 0.12%.

CLINICAL SIGNIFICANCE

The photocatalytic disinfection can be an alternative protocol to provide the oral decontamination.

Clinical Evaluation of Diode (980 nm) Laser-Assisted Nonsurgical Periodontal Pocket Therapy: A Randomized Comparative Clinical Trial and Bacteriological Study

Background: Mechanical debridement is the gold standard in the periodontitis therapy. However, it is suggested that adjunctive use of lasers can result in a more effective treatment outcome. Objective: Evaluate the efficiency of diode laser-assisted nonsurgical therapy of periodontitis as adjunctive to scaling and root planing (SRP). Methods: One hundred sixty vertical bone defects [pocket depth (PD) at baseline ≥6 mm] had been randomly allocated to receive SRP alone (group C) or SRP coupled to a diode laser (980 nm) protocol (group C+L): SRP, irrigation with hydrogen peroxide solution (3%), de-epithelization of the internal and external gingiva followed by blood stabilization, and coagulation by laser beam were made. Beam parameters: 10 μsec/pulse duration, 10 kHz, pick power of 10 W, average power of 1 W, and fiber diameter of 400 μm. Plaque index (PI), bleeding on probing, gingival recession (GR), clinical attachment level (CAL), and PD were measured at baseline, at 6 weeks, 12 weeks, 18 weeks, 6 months, and 12 months. Microbiological data were collected randomly from 26 pockets from both groups at baseline, 6 weeks, 12 weeks, and 6 months after treatment. Results: At all periods of follow-up, there was a significant difference between both groups in all clinical parameters except in GR. In group C+L, 76% of pockets had PD ≤3 mm after 12 months of follow-up and an average of PD = 1.77 ± 0.46 mm, while 56% of pockets in group control (C) had an average of PD = 5.00 ± 0.83 mm after 12 months of follow-up. Total bacteria count in group C + L was significantly lower compared to group C only at 12 weeks and 6 months of follow-up. Furthermore, there was high significant decrease in the number of Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Tannerella forsythia, and Prevotella intermedia at all the follow-up periods. Conclusions: As adjunctive to SRP, diode laser-assisted nonsurgical therapy of periodontitis has significantly improved clinical parameters of PI and POB and has significantly reduced the clinical attachment loss (CAL) and PD compared to the control group after 1 year of follow-up. A significant reduction in periodontal pathogens has been observed in group C + L only at 12 weeks and 6 months of follow-up.

Oral mucosal irritation potential of antimicrobial chemotherapy involving hydrogen peroxide photolysis with high-power laser irradiation for the treatment of periodontitis

In the present study, we assessed the oral mucosal irritation potential of antimicrobial chemotherapy involving hydrogen peroxide (H₂O₂) photolysis with a 405-nm laser device at an output power of ≥100 mW in hamsters. Twenty-four cheek pouches from 12 male Syrian hamsters received 7-min treatment with pure water (PW), 3% H₂O₂, laser irradiation of PW at 100 mW, laser irradiation of 3% H₂O₂ at 100 mW, laser irradiation of PW at 200 mW, or laser irradiation of 3% H₂O₂ at 200 mW (n = 4 each). The diameter of the irradiation area was set at 3 mm; accordingly, the calculated irradiances (optical power densities) of the 100- and 200-mW laser lights were approximately 1400 and 2800 mW/cm², respectively. In addition, 12 cheek pouches from six animals received laser irradiation of 3% H₂O₂ at 100 mW for 1, 3, or 5 min (n = 4 each). Each treatment was repeated three times at 1-h intervals. Macroscopic and histological changes were evaluated 24 h after the last treatment. In addition, in vitro bactericidal activity of the treatment against periodontal pathogens was evaluated. We found that 405-nm laser irradiation of 3% H₂O₂ caused moderate to severe oral mucosal irritation when performed at powers of 100 and 200 mW for ≥3 min, while the same treatment performed at 100 mW for 1 min resulted in mild irritation. Moreover, 1-min H₂O₂ photolysis at 100 mW caused a >4-log decrease in viable bacterial counts. These findings suggest that 1-min H₂O₂ photolysis, which can effectively kill periodontal pathogens, may be acceptable when a 405-nm laser device is used at 100 mW. However, use of the laser at a lower power would be preferable for the prevention of unnecessary oral mucosal irritation.

Hydroxyl radicals generated by hydrogen peroxide photolysis recondition biofilm-contaminated titanium surfaces for subsequent osteoblastic cell proliferation

Titanium dental implants have been successfully used for decades; however, some implants are affected by peri-implantitis due to bacterial infection, resulting in loss of supporting bone. This study aimed to evaluate the effect of an antimicrobial chemotherapy employing H₂O₂ photolysis-developed to treat peri-implantitis-on biofilm-contaminated titanium surfaces in association with osteoblastic cell proliferation on the treated surface. Titanium discs were sandblasted and acid-etched, followed by contamination with a three-species biofilm composed of Porphyromonas gingivalis, Fusobacterium nucleatum, and Streptococcus mitis. This biofilm model was used as a simplified model of clinical peri-implantitis biofilm. The discs were subjected to ultrasound scaling, followed by H₂O₂ photolysis, wherein 365-nm LED irradiation of the disc immersed in 3% H₂O₂ was performed for 5 min. We analysed proliferation of mouse osteoblastic cells (MC3T3-E1) cultured on the treated discs. Compared with intact discs, biofilm contamination lowered cell proliferation on the specimen surface, whereas H₂O₂ photolysis recovered cell proliferation. Thus, H₂O₂ photolysis can recover the degraded biocompatibility of biofilm-contaminated titanium surfaces and can potentially be utilised for peri-implantitis treatment. However, to verify the findings of this study in relation to clinical settings, assessment using a more clinically relevant multi-species biofilm model is necessary.

Notch pathway deactivation mediated by F-box/WD repeat domain-containing 7 ameliorates hydrogen peroxide-induced apoptosis in rat periodontal ligament stem cells

OBJECTIVE

To investigate the protective role of F-box/WD repeat domain-containing 7 in rat periodontal ligament stem cells under oxidative stress.

MATERIALS AND METHODS

The apoptosis of rat periodontal ligament stem cells was induced by exposure to various concentrations of hydrogen peroxide for 24 h, after which cell viability and the cleaved caspase-3 and -9 levels were determined. The levels of proteins in the Notch signaling pathway were determined by western blotting.

RESULTS

The overexpression of F-box/WD repeat domain-containing 7 increased cell viability following hydrogen peroxide administration and suppressed the activation of caspases-3 and -9. The overexpression of F-box/WD repeat domain-containing 7 inhibited Notch signaling. Furthermore, the protective effect of F-box/WD repeat domain-containing 7 could be resumed by PF-03084014, a Notch-specific inhibitor.

CONCLUSIONS

These observations suggest a protective role of F-box/WD repeat domain-containing 7 against hydrogen peroxide-induced oxidative stress in rat periodontal ligament stem cells. These findings will facilitate the in vitro culturing of periodontal ligament stem cell for clinical usage and promote stem cell-based therapy for periodontal tissue regeneration.

Adjunctive antimicrobial chemotherapy based on hydrogen peroxide photolysis for non-surgical treatment of moderate to severe periodontitis: a randomized controlled trial

Treatment of severe periodontitis with non-surgical therapy remains challenging in dentistry. The present study aimed to evaluate the clinical efficacy of hydrogen peroxide (H₂O₂) photolysis-based antimicrobial chemotherapy adjunctively performed with root debridement (RD) for moderate to severe periodontitis. A randomized controlled trial was conducted that included 53 patients with 142 test teeth. The test teeth were randomly assigned to one of three treatment groups: Group 1, RD + H₂O₂ photolysis; Group 2, RD followed by administration of a local drug delivery system (minocycline chloride gel); or Group 3, RD alone. Clinical and microbiological examination were performed for up to 12 weeks following treatment. Probing pocket depth (PPD) and bleeding on probing (BoP) were improved after each treatment session. At 12 weeks, Group 1 had achieved significantly lower PPDs than the other groups, though there were no significant differences in BoP between Group 1 and the other groups. Counts of Porphyromonas gingivalis, a known periodontal pathogen, in Group 1 were significantly lower than those in Group 3, and were comparable to those in Group 2. Therefore, it is suggested that H₂O₂ photolysis treatment can be used as a novel adjunctive antimicrobial chemotherapy for non-surgical periodontal treatment.

Antimicrobial Intervention by Photoirradiation of Grape Pomace Extracts via Hydroxyl Radical Generation

The annual production of grape worldwide amounts to almost 70 million tons, and around 80% is used for winemaking. The two major wastes from winemaking process, pomace and lees account for 20 and 7% of the grapes, respectively. They have been expected as a valuable resource to be recycled because they are rich in polyphenols. Polyphenols possess prooxidatve activity as well as antioxidative one just like a two sides of a coin. A typical example of the prooxidative activity is antibacterial activity of catechins. The activity is exerted through oxidation of phenolic hydroxyl moiety coulpled with reduction of dissolved oxygen leading to hydrogen peroxide (H₂O₂) generation. In addition, once the oxidation of phenolic hydroxyl moiety is augmented by photoirradiation, highly reactive hydroxyl radical (·OH) is generated. Accordingly, there have been several reports showing that photoirardiation of polyphenols exerts bactericidal activity via ·OH generation. This review focuses mainly on antimicrobial intervention by photoirradiation of grape pomace extract in relation to ·OH generation analyzed by an electron spin resonance-spin trapping method.