Evaluation of photodynamic therapy using a light-emitting diode lamp against Enterococcus faecalis in extracted human teeth.

Introduction: Photodynamic therapy (PDT) with high-power lasers as the light source has been proven to be effective in disinfecting root canals. The aim of this study was to evaluate the antimicrobial effect of PDT using toluidine blue O (TBO) and a low-energy light-emitting diode (LED) lamp after the conventional disinfection protocol of 6% NaOCl.

Methods: Single-rooted extracted teeth were cleaned, shaped, and sealed at the apex before incubation with Enterococcus faecalis for 2 weeks.

Determinants of enamel decalcification during simulated orthodontic treatment.

Objective: To determine the relative effects that phosphoric acid etching, metal brackets, composite resin adhesives, and filled resin sealants have on enamel decalcification.

Materials And Methods: One hundred and fifty teeth were randomly divided into six groups to test the effects of acid etching, brackets, and a composite resin adhesive. The right side of each tooth was sealed.

Does the amount of filler content in sealants used to prevent decalcification on smooth enamel surfaces really matter?

Objective: To determine how filler content and an acidic environment affect the retention of sealants placed on smooth enamel surfaces.

Materials And Methods: A sample of 120 teeth was randomly divided into six subsamples. Three experimental sealants with identical formulas, with the exception of the amount of filler content (18%, 30%, 50%), were applied according to manufacturers' recommendations.

Antimicrobial effects of zinc oxide in an orthodontic bonding agent.

Objective: To test the null hypothesis that the addition of zinc oxide (ZnO) has no effect on the antimicrobial benefits and shear bond strength of a light-cured resin-modified glass ionomer.

Materials And Methods: ZnO was added to Fuji Ortho LC to create mixtures of 13% ZnO and 23.1% ZnO.

Comparative assessment of ActiV GP/glass ionomer sealer, Resilon/Epiphany, and gutta-percha/AH plus obturation: a bacterial leakage study.

The objective of this study was to compare the sealing ability of ActiV GP/glass ionomer (GI) sealer (Brasseler USA, Savannah, GA), Resilon/Epiphany (Pentron Clinical Technologies, Wallingford, CT), and gutta-percha (GP)/AH Plus (Dentsply Maillefer, Tulsa, OK). Seventy-three human single-rooted teeth were randomly divided into three test groups (20 canals each) and two control groups (5 positive and 8 negative). Using Enterococcus faecalis, a split-chamber bacterial leakage model was developed to evaluate the sealing ability of the three obturation systems.

Overlapping substrate specificity for sucrose and maltose of two binding protein-dependent sugar uptake systems in Streptococcus mutans.

Sugar metabolism by Streptococcus mutans is associated with tooth decay. The most abundant sugars in the human diet are sucrose and maltose, a derivative of starch. Previously, we reported a binding protein-dependent transport system (msm) in S.

Comparative evaluation of endodontic irrigants against Enterococcus faecalis biofilms.

The aim of this study was to compare the efficacy of root canal irrigants against E. faecalis biofilms using a novel in vitro testing system. Biofilms grown in a flow cell system were submerged in test irrigants for either 1 or 5 minutes.

Transcriptional analysis of the bglP gene from Streptococcus mutans.

Background: An open reading frame encoding a putative antiterminator protein, LicT, was identified in the genomic sequence of Streptococcus mutans. A potential ribonucleic antitermination (RAT) site to which the LicT protein would potentially bind has been identified immediately adjacent to this open reading frame. The licT gene and RAT site are both located 5' to a beta-glucoside PTS regulon previously described in S.

The LicT protein acts as both a positive and a negative regulator of loci within the bgl regulon of Streptococcus mutans.

An open reading frame (ORF) that would encode a putative antiterminator protein (LicT) of the BglG family was identified in the genomic DNA sequence of Streptococcus mutans. A DNA sequence that would encode a potential ribonucleic antiterminator (RAT) site in the mRNA at which the putative antitermination protein LicT would bind was located immediately downstream from this ORF. These putative antitermination components are upstream of a glucose-independent beta-glucoside-utilization system that is responsible for aesculin utilization by S.

The transcriptional regulation of the Streptococcus mutans bgl regulon.

A beta-glucoside utilization regulon recently isolated from Streptococcus mutans has been shown to contain genes involved in beta-glucoside hydrolysis and a putative regulator. The bglP gene encodes a beta-glucoside-specific enzyme II (EII) component of the phosphoenolpyruvate-dependent phosphotransferase system, the bglC gene encodes a putative transcriptional regulator, and the bglA gene encodes a putative phospho-beta-glucosidase. To investigate the transcriptional activity of these genes, the putative promoter regions of the bglP, bglC and bglA genes were fused with the E.

Construction of transcriptional and translational lacZ gene reporter plasmids for use in Streptococcus mutans.

Reporter genes have become standard genetic tools used to evaluate either the transcriptional or the translational activity associated with genes of interest, whose products cannot be easily assayed. The lacZ gene from Escherichia coli has been used very effectively to quantify such regulated activities in many different organisms. This report describes the construction of a pair of plasmids that may be used for either transcriptional or translational lacZ gene fusions in Streptococcus mutans.

The mannitol-specific enzyme II (mtlA) gene and the mtlR gene of the PTS of Streptococcus mutans.

The phosphoenolpyruvate-dependent phosphotransferase system (PTS) is widely found among Gram-positive bacteria. It is the major source of carbohydrate transport in the dental pathogen Streptococcus mutans. The transported carbohydrates are fermented to produce large amounts of lactic acid which initiates dental caries.

A novel beta-glucoside-specific PTS locus from Streptococcus mutans that is not inhibited by glucose.

A regulon from Streptococcus mutans that plays a role in the utilization of beta-glucosides has been isolated, sequenced and subjected to sequence analysis. This regulon encodes a beta-glucoside-specific Enzyme II (EII) component (bglP) of the phosphoenolpyruvate-dependent phosphotransferase system (PTS) and a phospho-beta-glucosidase (bglA) which is responsible for the breakdown of the phospho-beta-glucosides within the cell. Both the bglP and bglA gene products have significant similarity with proteins that have similar functions from Clostridium longisporum, Listeria monocytogenes, Erwinia chrysanthemi, Escherichia coli, Klebsellia oxytoca and Bacillus subtilis.