Bactericidal effect of Er,Cr:YSGG laser irradiation on endodontic biofilm: An ex vivo study.

AIM: This ex vivo study aimed to evaluate the of Er,Cr:YSGG laser effectiveness in the decontamination of an endodontic biofilm. MATERIALS AND METHODS: Seventy-three single rooted human teeth, freshly were chosen. Each tooth was exposed to four associated species in an endodontic biofilm (Enterococcus faecalis, Streptococcus salivarius, Porphyromonas gingivalis, and Prevotella intermedia) and randomly allocated to one of the seven experimental groups. The group 1 (7 teeth) was used to finalize the reliable biofilm-forming technique. The groups 2 and 3 (15 teeth each group) were irradiated with two different Er;Cr:YSGG laser settings (0,75 W - 40 Hz and 4 W - 40 Hz, respectively). The groups 4 and 5 (15 teeth each group) were irrigated with two different solutions and laser irradiated with the same settings (1,5 W - 15 Hz). The group 6 (6 teeth) was the control group treated only with 4 ml 2,5% NaOCl irrigation during 60 s. RESULTS: The observations of group 2 and 3 specimens showed the ripeness of the biofilm with the presence of Enterococcus faecalis and Streptococcus salivarius in chains but in group 3 thermal edge effects produced by the optic fiber in the canal walls were present. The group 4 specimens observation showed an average cleaning of the root canal walls while on the canal walls of group 5 samples the apical third presented several debris and smear layer and in the centre cracks and melting dentin of the radicular wall were observed. CONCLUSION: In those experimental conditions, this study, demonstrated that Er,Cr:YSGG laser has a canals decontamination ability when associated to NaOCl irrigation.

Photodynamic therapy versus ultrasonic irrigation: interaction with endodontic microbial biofilm, an ex vivo study.

INTRODUCTION: Photodynamic therapy was introduced as an adjuvant to conventional chemo-mechanical debridement during endodontic treatment to overcome the persistence of biofilms. The aim of this study was to evaluate the ability of photodynamic therapy (PDT) to disrupt an experimental microbial biofilm inside the root canal in a clinically applicable working time. MATERIALS AND METHODS: Thirty extracted teeth were prepared and then divided in three groups. All samples were infected with an artificially formed biofilm made of Enterococcus faecalis, Streptococcus salivarius, Porphyromonas gingivalis and Prevotella intermedia bacteria. First group was treated with Aseptim Plus® photo-activated (LED) disinfection system, second group by a 650 nm Diode Laser and Toluidine blue as photosensitizer, and the third group, as control group, by ultrasonic irrigation (PUI) using EDTA 17% and NaOCl 2.6% solutions. The working time for all three groups was fixed at 3 min. Presence or absence of biofilm was assessed by aerobic and anaerobic cultures. RESULTS: There was no statistically significant difference between results obtained from groups treated by Aseptim Plus® and Diode Laser (P<0.6267). In cultures of both groups there was a maximal bacterial growth. The group that was treated by ultrasonic irrigation and NaOCl and EDTA solutions had the best results (P<0.0001): there was a statistically significant reduction of bacterial load and destruction of microbial biofilm. CONCLUSION: Under the condition of this study, Photodynamic therapy could not disrupt endodontic artificial microbial biofilm and could not inhibit bacterial growth in a clinically favorable working time.

Triterpenoid saponins from the aerial parts of Solidago virgaurea alpestris with inhibiting activity of Candida albicans yeast-hyphal conversion.

As part of research for treatments to combat oral dryness, our evaluation of the activity of an aqueous extract of Solidago virgaurea (L.) ssp. alpestris (Asteraceae) revealed activity against Candida albicans hyphae, the pathogenic form of this yeast. Systematic bioassay-guided fractionation of this extract gave an active saponin-containing fraction from which six oleanane-type triterpenoid saponins were isolated. Three of these were isolated for the first time, as 3-O-(ß-D-glucopyranosyl-(1→3)-ß-D-glucopyranosyl)-28-O-(ß-D-fucopyranosyl-(1→2)-α-L-rhamnopyranosyl-(1→3)-ß-D-xylopyranosyl-(1→4)-α-L-rhamnopyranosyl-(1→2)-ß-D-xylopyranosyl)-polygalacic acid (virgaureasaponin 4), 3-O-(ß-D-glucopyranosyl)-28-O-(ß-D-fucopyranosyl-(1→2)-α-L-rhamnopyranosyl-(1→3)-ß-D-xylopyranosyl-(1→4)-α-L-rhamnopyranosyl-(1→2)-ß-D-xylopyranosyl)-polygalacic acid (virgaureasaponin 5) and 3-O-(ß-D-glucopyranosyl)-28-O-(α-L-rhamnopyranosyl-(1→3)-ß-D-xylopyranosyl-(1→4)-α-L-rhamnopyranosyl-(1→2)-[5-O-acetylapiofuranosyl-(1→3)-[4-O-(3-(3-hydroxy-1-oxobutoxy)-1-oxobutyl)]-ß-D-fucopyranosyl]-polygalacic acid (virgaureasaponin 6). Their structures were established by carrying out 1D and 2D NMR experiments along with HRMS analyses. All of the six saponins were evaluated to ascertain their inhibition of C. albicans yeast-hyphal conversion, and four of them showed significant inhibition.

Inhibition of Candida albicans yeast-hyphal transition and biofilm formation by Solidago virgaurea water extracts.

Xerostomia is a decrease of saliva secretion, which can unbalance the oral microflora, mainly to the benefit of Candida albicans. The aim of the present study was to find a plant extract that could create an unfavourable environment for Candida, and would, therefore, be appropriate for use in a dry-mouth daily-care mouthwash. Water extract from the herbaceous plant Solidago virgaurea (Goldenrod) was selected due to its saponin content (plant detergents). Saponin concentrations reached 0.7 and 0.95 mg ml(-1) in S. virgaurea subsp. virgaurea and S. virgaurea subsp. alpestris extracts, respectively. C. albicans was grown in liquid medium and cells were counted by microscopic examination after 0, 4 and 24 h of incubation. Solidago extracts did not inhibit the growth of C. albicans (four strains), Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Streptococcus mutans, Streptococcus salivarius or Enterococcus faecalis. When inocula were incubated with Solidago extract for 4 and 24 h, we observed a decrease in Candida yeast-hyphal transition. Candida biofilms were then prepared in microtitre plates and treated with plant extracts at 0 h, to estimate biofilm formation, or at 18 h to estimate the effect of the saponin on pre-formed biofilms. Biofilm formation and pre-formed biofilms were both strongly inhibited. In conclusion, the S. virgaurea extract was efficient against two key virulence factors of C. albicans: the yeast-hyphal transition phase and biofilm formation.