Comparison of biofilm models for producing artificial active white spot lesions.

Objective: This study compared three protocols for developing artificial white spot lesions (WSL) using biofilm models.

Methodology: In total, 45 human enamel specimens were sterilized and allocated into three groups based on the biofilm model: Streptococcus sobrinus and Lactobacillus casei (Ss+Lc), Streptococcus sobrinus (Ss), or Streptococcus mutans (Sm). Specimens were incubated in filter-sterilized human saliva to form the acquired pellicle and then subjected to the biofilm challenge consisting of three days of incubation with bacteria (for demineralization) and one day of remineralization, which was performed once for Ss+Lc (four days total), four times for Ss (16 days total), and three times for Sm (12 days total).

Role of mutans streptococci, acid tolerant bacteria and oral species in predicting the onset of early childhood caries.

Aim: Early childhood caries is the most common chronic infectious disease in children in the United States. This study, which is part of a larger, longitudinal study exploring oral microbiological components of caries development in children, reports on the impact of total mutans streptococci (MS), total acid tolerant bacteria and species on the development of dental caries in a subset of these children. Of particular interest was the relationship between caries development and co-colonization of mutans streptococci and species.

A Social Media Intervention for Promoting Oral Health Behaviors in Adolescents: A Non-Randomized Pilot Clinical Trial.

Poor oral hygiene and excessive consumption of soda are among the main drivers of systemic health issues in adolescents in the United States. This non-randomized pilot clinical trial focused on the effects of a health text message system and smartphone-based intervention on adolescent tooth-brushing behavior and dietary choices, with a convenience sample of 94 participants aged 12 to 14 years old. A group of 75 participants agreed to use a tooth-brushing app and received a health text message; the other group of 15 agreed to use the tooth-brushing app, but did not receive a health text message.

Choline and geranic acid (CAGE) ionic liquids inhibit both elastase activity and growth of oral bacteria.

Choline and geranic acid (CAGE) ionic liquids have recently been shown to have applications in the delivery of macromolecules and poorly soluble drugs across epithelial barriers and in bacterial growth inhibition. Ionic liquids are known to denature proteins by the disruption of forces that guide natural protein folding, and the inflammatory enzyme elastase was recently shown to be inhibited by a variety of ionic liquids other than CAGE. Inhibition of collagenolytic enzymes, including elastase, has been shown to improve outcomes in cases of periodontitis via amelioration of periodontal inflammation and alveolar bone resorption.

Spent culture supernatant of Streptococcus gordonii mitigates inflammation of human periodontal cells and inhibits proliferation of pathogenic oral microbes.

Background: The oral commensal bacterial species Streptococcus gordonii has been reported to regulate the inflammation of oral epithelial cells stimulated by the periodontal pathogen Porphyromonas gingivalis. This study investigated the activities of S. gordonii metabolites in S.

Vanillin-bioglass cross-linked 3D porous chitosan scaffolds with strong osteopromotive and antibacterial abilities for bone tissue engineering.

Chitosan scaffolds crosslinked by current methods insufficiently meet the demands of bone tissue engineering applications. We developed a novel effective crosslinking technique by using the natural and safe vanillin together with bioglass microparticles to generate an antibacterial, osteoconductive, and mechanically robust 3D porous chitosan-vanillin-bioglass (CVB) scaffold. In addition to the significantly improved mechanical properties, the CVB scaffolds had high porosity (>90%) and interconnected macroporous structures.

Solubilized ubiquinol for preserving corneal function.

Defective cellular metabolism, impaired mitochondrial function, and increased cell death are major problems that adversely affect donor tissues during hypothermic preservation prior to transplantation. These problems are thought to arise from accumulated reactive oxygen species (ROS) inside cells. Oxidative stress acting on the cells of organs and tissues preserved in hypothermic conditions before surgery, as is the case for cornea transplantation, is thought to be a major reason behind cell death prior to surgery and decreased graft survival after transplantation.

Antimicrobial efficacy of platinum-doped silver nanoparticles.

Silver nanoparticles (AgNPs) have been proposed to combat oral infection due to their efficient ionic silver (Ag ) release. However, concentrations required for antimicrobial efficacy may not be therapeutically viable. In this work, platinum-doped silver nanoparticles (Pt-AgNPs) were explored to evaluate their potential for enhanced Ag release, which could lead to enhanced antimicrobial efficacy against S.

Dental adhesive microtensile bond strength following a biofilm-based in vitro aging model.

Objective: Laboratory tests are routinely used to test bonding properties of dental adhesives. Various aging methods that simulate the oral environment are used to complement these tests for assessment of adhesive bond durability. However, most of these methods challenge hydrolytic and mechanical stability of the adhesive- enamel/dentin interface, and not the biostability of dental adhesives.

Evaluating the relationship between acidogenicity and acid tolerance for oral streptococci from children with or without a history of caries.

: Dental caries etiology is attributed to a dysbiotic imbalance within the plaque microbiome leading to a dominance of strong acidogens. Some studies that investigate the link between acidogens and caries quantify the recovery of acid tolerant strains on acid agar as a measure of acidogenic potential. This methodology assumes that acidogenic potential and acid tolerance are directly related.

Are the mutans streptococci still considered relevant to understanding the microbial etiology of dental caries?

The mutans streptococci were once the primary focus of research dedicated to understanding the etiology of dental caries. That focus has now shifted to an emphasis on the ecological balances and complexities within the entirety of the plaque microbiome. Within that framework there are considerable differences of opinion regarding the importance and relative contributions of the mutans streptococci.

Acidogenicity and acid tolerance of and isolated from plaque of healthy and incipient caries teeth.

Background: Non-mutans low pH oral streptococci are postulated to contribute to caries etiology.

Objective: This study was undertaken to investigate whether the acidogenicity and acid tolerance of clinical strains of and correlate with health or early-stage enamel caries.

Design: and were isolated from plaque samples taken from the occlusal surfaces of second molars sampled at two different visits 4 years apart.

PCR-Based Identification of Oral Streptococcal Species.

The microbial etiology of dental caries is still debated. Among the hypothesized contributors are the "low pH streptococci," a designation given to unusually acid proficient strains among the primary plaque colonizers , , , and . However, accurate assignment of species is difficult among the oral streptococci.

Discovery of antifungal constituents from the Miao medicinal plant Isodon flavidus.

Ethnopharmacological Relevance: Leigong Mountain is an area in the Southwest of China where there is a high incidence rate of athlete's foot, but the Miao people, a Chinese minority who reside in this mountainous area have suffered less from this disease due to their use of the herbal medicine Isodon flavidus (Hand.-Mazz.) H.

Codon-optimized fluorescent mTFP and mCherry for microscopic visualization and genetic counterselection of streptococci and enterococci.

Despite the powerful potential of fluorescent proteins for labeling bacteria, their use has been limited in multi-species oral biofilm models. Fermentative metabolism by streptococcal species that initiate biofilm colonization results in an acidic, reduced microenvironment that may limit the activities of some fluorescent proteins which are influenced by pH and oxygen availability. The need to reliably distinguish morphologically similar strains within biofilms was the impetus for this work.

Cariogenicity of Streptococcus mutans glucan-binding protein deletion mutants.

Streptococcus mutans is a principal etiologic agent in the development of dental caries due to its exceptional aciduric and acidogenic properties, and its ability to adhere and accumulate in large numbers on tooth surfaces in the presence of sucrose. Sucrose-dependent adherence is mediated by glucans, polymers of glucose synthesized from sucrose by glucosyltransferase (Gtf) enzymes. S.

Recovery of Viable Bacteria from Probiotic Products that Target Oral Health.

Probiotic therapy has predominantly been directed toward promoting and maintaining intestinal health. In recent years, however, probiotic regimens that target oral health have appeared on the market. These regimens are often delivered in the form of lozenges.

Rubesanolides C-E: abietane diterpenoids isolated from Isodon rubescens and evaluation of their anti-biofilm activity.

Phytochemical study of the leaves of the medicinal plant Isodon rubescens led to the isolation of three novel abietane diterpenoids, rubesanolides C-E (1-3). These diterpenes contain a unique γ-lactone subgroup formed between C-8 and C-20. Their structures were determined from analysis of spectroscopic data, and were further confirmed by X-ray crystallographic data.

Effects of DNA methylation on expression of virulence genes in Streptococcus mutans.

Bacteria produce a variety of enzymes capable of methylating DNA. In many species, the majority of adenine methylation is accomplished by the DNA adenine methylase Dam. In Escherichia coli the Dam methylase plays roles in the initiation of replication, mismatch repair, and gene regulation.

Role of the Streptococcus mutans irvA gene in GbpC-independent, dextran-dependent aggregation and biofilm formation.

Dextran-dependent aggregation (DDAG) of Streptococcus mutans is an in vitro phenomenon that is believed to represent a property of the organism that is beneficial for sucrose-dependent biofilm development. GbpC, a cell surface glucan-binding protein, is responsible for DDAG in S. mutans when cultured under defined stressful conditions.

Genome-wide identification of Francisella tularensis virulence determinants.

Francisella tularensis is a gram-negative pathogen that causes life-threatening infections in humans and has potential for use as a biological weapon. The genetic basis of the F. tularensis virulence is poorly understood.

Glucan-binding proteins are essential for shaping Streptococcus mutans biofilm architecture.

Glucan plays a central role in sucrose-dependent biofilm formation by the dental pathogen Streptococcus mutans. This organism synthesizes several proteins capable of binding glucan. These are divided into the glucosyltransferases that catalyze the synthesis of glucan and the nonglucosyltransferase glucan-binding proteins (Gbps).

Streptococcus mutans glucan-binding protein-A affects Streptococcus gordonii biofilm architecture.

The glucan-binding protein-A (GbpA) of Streptococcus mutans has been shown to contribute to the architecture of glucan-dependent biofilms formed by this species and influence virulence in a rat model. As S. mutans synthesizes multiple glucosyltransferases and nonglucosyltransferase glucan-binding proteins (GBPs), it is possible that there is functional redundancy that overshadows the full extent of GbpA contributions to S.