Bactericidal activity and recovery effect of hydroxyl radicals generated by ultraviolet irradiation and silver ion application on an infected titanium surface.

This study investigated the bactericidal effect, the underlying mechanisms of treatment, and recovery of biocompatibility of the infected titanium surface using a combination treatment of silver ion application and ultraviolet-A (UV-A) light irradiation. Streptococcus mutans and Aggregatibacter actinomycetemcomitans were used in suspension and as a biofilm on a titanium surface to test for the bactericidal effect. The bactericidal effect of the combination treatment was significantly higher than that of silver ion application or UV-A light irradiation alone.

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 (HO) 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% HO, laser irradiation of PW at 100 mW, laser irradiation of 3% HO at 100 mW, laser irradiation of PW at 200 mW, or laser irradiation of 3% HO 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/cm, respectively.

Potential adverse effects of antimicrobial chemotherapy based on ultraviolet-A irradiation of polyphenols against the oral mucosa in hamsters and wounded skin in rats.

Antimicrobial chemotherapy based on ultraviolet-A (UVA) irradiation of polyphenol solution has been proposed as an adjunctive treatment for dental caries. However, the safety of this treatment has not been thoroughly evaluated. Therefore, the aim of the present study was to assess the influence of this treatment on the oral mucosa in hamsters and wounded skin in rats.

Proanthocyanidin-Rich Grape Seed Extract Modulates Intestinal Microbiota in Ovariectomized Mice.

Unlabelled: Grape-seed extract (GSE) is rich in proanthocyanidins (polymers of flavan-3-ols). GSE is well known to have various beneficial effects to health. The objective of this study was to examine the effect of dietary GSE on the intestinal microbiota in ovariectomized (OVX) mice as a model of menopause.

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 (HO) 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.

Bactericidal Action of Photodynamic Antimicrobial Chemotherapy (PACT) with Photosensitizers Used as Plaque-Disclosing Agents against Experimental Biofilm.

Our previous study revealed that the photo-irradiation of rose bengal, erythrosine, and phloxine, xanthene photosensitizers, used as dental plaque disclosing agents, could exert bactericidal action on planktonic Streptococcus mutans via the singlet oxygen. In the present study, the photo-irradiation induced bactericidal activity of the three xanthene compounds against the experimental biofilm of S. mutans was investigated in combination with acid electrolyzed water (AcEW) and alkaline electrolyzed water (AlEW).

Bactericidal Activity and Mechanism of Photoirradiated Polyphenols against Gram-Positive and -Negative Bacteria.

The bactericidal effect of various types of photoirradiated polyphenols against Gram-positive and -negative bacteria was evaluated in relation to the mode of action. Gram-positive bacteria (Enterococcus faecalis, Staphylococcus aureus, and Streptococcus mutans) and Gram-negative bacteria (Aggregatibacter actinomycetemcomitans, Escherichia coli, and Pseudomonas aeruginosa) suspended in a 1 mg/mL polyphenol aqueous solution (caffeic acid, gallic acid, chlorogenic acid, epigallocatechin, epigallocatechin gallate, and proanthocyanidin) were exposed to LED light (wavelength, 400 nm; irradiance, 260 mW/cm(2)) for 5 or 10 min. Caffeic acid and chlorogenic acid exerted the highest bactericidal activity followed by gallic acid and proanthocyanidin against both Gram-positive and -negative bacteria.

Reevaluation of analytical methods for photogenerated singlet oxygen.

The aim of the present study is to compare different analytical methods for singlet oxygen and to discuss an appropriate way to evaluate the yield of singlet oxygen photogenerated from photosensitizers. Singlet oxygen photogenerated from rose bengal was evaluated by electron spin resonance analysis using sterically hindered amines, spectrophotometric analysis of 1,3-diphenylisobenzofuran oxidation, and analysis of fluorescent probe (Singlet Oxygen Sensor Green®). All of the analytical methods could evaluate the relative yield of singlet oxygen.