Application of non-inferiority testing in microhardness and its relationship to erosion: Relevance for hard tissue safety evaluations.

Purpose: To use non-inferiority statistical testing with simple microhardness measurements (SMH) as a prediction of potential erosive hard tissue damage of topical treatments on enamel.

Methods: Three independent experiments of a simple acid cycling demineralization (ACD) model were used to screen softening effects of various commercial beverages on dental enamel. The cycling model consists of six repeated exposures of enamel slabs with alternating treatments of artificial saliva over the course of 6 hours.

Laboratory screening evaluation of the safety of low pH oral care rinse products to dental enamel.

Purpose: To assess the hard tissue safety of a variety of low pH oral care rinses to dental enamel in a newly developed screening method.

Methods: Bovine enamel specimens were subjected to a cycling model that consisted of commercial mouthrinse product exposures and artificial saliva soaks based on a previously published screening method. The effect of test products on the surface of treated specimens was measured using surface microhardness (SMH).

Development of a Screening Method to Establish if pH of Oral Care Products Affects Hard Tissues.

Objectives: To develop a transferable, simple screening method to evaluate the effect of pH of oral care products on oral hard tissues.

Methods: The method reported here is based on the assessment of oral hard surface changes produced by oral care products measured via Vickers Surface Microhardness (SMH). Two variations of this screening test method were developed, one including the use of salivary pellicle and human teeth and a second using bovine substrates with artificial saliva.

Clinical effects of stannous fluoride dentifrice in reducing plaque microbial virulence III: Lipopolysaccharide and TLR2 reporter cell gene activation.

Purpose: This study expanded the analysis of subgingival dental plaques from previous research to include the evaluation of cohort, site and treatment effects on chemically measured endotoxin and activation of Toll-like receptor (TLR) based gene expression in two additional reporter cell lines: a TLR2 specific cell line and a THP-1 (multi TLR reporter) cell line.

Methods: Participants from high and low bleeding cohorts were sampled at baseline for both supra and subgingival dental plaque at both healthy as well as clinically diseased sites and then provided with intervention hygiene products including a stabilized SnF₂ dentifrice and a new soft bristle manual toothbrush. Following 2 and 4 weeks of assigned dentifrice use, participants returned for a re-evaluation of gingival inflammation and bleeding and repeat samplings of dental plaque.

Subgingival uptake and retention of stannous fluoride from dentifrice: Gingival crevicular fluid concentrations in sulci post-brushing.

Purpose: To examine the delivery of stannous fluoride to subgingival sulci following toothpaste use in a clinical population.

Methods: This was a controlled, single-site study. 23 subjects with at least 20 dental pockets, 2-4 mm with bleeding, who had not used a stannous fluoride dentifrice in the last 3 months were enrolled.

Clinical Effects of Stabilized Stannous Fluoride Dentifrice in Reducing Plaque Microbial Virulence II: Metabonomic Changes.

Objectives: The clinical effects of stannous fluoride (SnF2) dentifrice in reducing symptoms of gingivitis and reducing the virulence of subgingival plaque through suppression of activation of gene expression in toll receptor based reporter cells were previously reported. This study expanded analysis of the clinical study to include evaluation of dentifrice effects on salivary metabolites using 1H Nuclear Magnetic Resonance (1H NMR) systems biology-based metabonomics.

Methods: The clinical design was reported previously (J Clin Dent2017;28:16-26).

A Profilometry-Based Dentifrice Abrasion Method for V8 Brushing Machines Part III: Multi-Laboratory Validation Testing of RDA-PE.

Objectives: We have previously reported on progress toward the refinement of profilometry-based abrasivity testing of dentifrices using a V8 brushing machine and tactile or optical measurement of dentin wear. The general application of this technique may be advanced by demonstration of successful inter-laboratory confirmation of the method. The objective of this study was to explore the capability of different laboratories in the assessment of dentifrice abrasivity using a profilometry-based evaluation technique developed in our Mason laboratories.

Lipopolysaccharide and lipoteichoic acid binding by antimicrobials used in oral care formulations.

Purpose: To study the reactivity of lipopolysaccharide (LPS) and lipoteichoic acid (LTA) with the cationically charged agents cetylpyridinium chloride, stannous fluoride, and the non-cationic agent triclosan. We also assessed the effect of these agents to inhibit LPS and LTA binding to cellular Toll-like Receptors (TLRs) in vitro.

Methods: The ability of these antimicrobials to bind with LPS and/or LTA was assessed in both the Limulus amebocyte lysate and BODIPY-TR-cadaverine dye assays.

Quantitation of endotoxin and lipoteichoic acid virulence using toll receptor reporter gene.

Purpose: To apply quantitative Toll-like receptors (TLR) cell assays to compare lipopolysaccharides (LPSs) and lipoteichoic acids (LTAs) from different oral bacterial strains for potential pathogenicity in vitro.

Methods: The potency of LPS and LTA from different bacteria on activation of TLR reporter genes in HEK-tlr cell lines was examined. P.

Clinical Effects of Stabilized Stannous Fluoride Dentifrice in Reducing Plaque Microbial Virulence I: Microbiological and Receptor Cell Findings.

Objectives: Lipopolysaccharides (LPSs) and lipoteichoic acids (LTAs), or bacterial endotoxins, bind with Toll-like receptors (TLRs) that are expressed on host cells of the periodontium, thereby contributing to the periodontal pathogenicity of oral bacteria. Stannous fluoride (SnF2), an antibacterial fluoride that treats and controls gingivitis, has been shown to react with lipophilic domains/anionic charges in LPS and LTA. The effects of bacterial species and dental plaque on toll receptors can be studied using genetically engineered cell lines containing linked toll receptors on their surfaces.

Lipopolysaccharide and Lipoteichoic Acid Virulence Deactivation by Stannous Fluoride.

Objectives: Oral bacterial pathogens promote gingivitis and periodontal disease. Bacterial endotoxins, also known as lipopolysaccharides (LPSs) and lipoteichoic acids (LTAs), are known to enhance bacterial pathogenicity through binding with Toll-like receptors (TLRs), a group of pattern recognition receptors critical to the activation of innate immunity, that are expressed on host cells. Both LPS and LTA contain lipophilic domains and anionic charges that may be susceptible to reactivity with stannous fluoride, a commonly used ingredient clinically proven for the treatment and prevention of gingivitis.

A Profilometry-Based Dentifrice Abrasion Method for V8 Brushing Machines Part II: Comparison of RDA-PE and Radiotracer RDA Measures.

Objective: The purpose of this study was to compare the abrasivity of commercial dentifrices by two techniques: the conventional gold standard radiotracer-based Radioactive Dentin Abrasivity (RDA) method; and a newly validated technique based on V8 brushing that included a profilometry-based evaluation of dentin wear. This profilometry-based method is referred to as RDA-Profilometry Equivalent, or RDA-PE.

Methods: A total of 36 dentifrices were sourced from four global dentifrice markets (Asia Pacific [including China], Europe, Latin America, and North America) and tested blindly using both the standard radiotracer (RDA) method and the new profilometry method (RDA-PE), taking care to follow specific details related to specimen preparation and treatment.

Response of chronic gingivitis to hygiene therapy and experimental gingivitis. Clinical, microbiological and metabonomic changes.

Purpose: To compare the clinical, microbiological and metabonomic profiles of subjects with high and low levels of chronic gingival bleeding during a controlled oral hygiene regimen intervention including sequential phases of rigorous therapeutic oral hygiene followed by experimental gingivitis (EG).

Methods: Two cohorts of qualified study subjects with differences in gingival bleeding on probing levels at their baseline clinical examination were entered into the study. These two cohorts were followed through three separate study phases including a 1-week baseline phase, a 2-week phase of rigorous oral hygiene including dental prophylaxis, and a 3-week EG phase of no oral hygiene to encourage relapse of gingivitis.

Characterization of cornified oral mucosa for iontophoretically enhanced delivery of chlorhexidine.

Topical administration of chlorhexidine for periodontal disease can provide advantages over systemic delivery, but is limited by the permeability of the cornified oral mucosal tissue. In the present study, passive and iontophoretic transport of tetraethylammonium, salicylate, mannitol, dexamethasone, fluoride, and chlorhexidine across bovine palate was investigated to (a) determine the intrinsic barrier properties of bovine palate for its eventual use as a model of human cornified oral mucosa, (b) examine the feasibility of iontophoretically enhanced transport of chlorhexidine into and across bovine palate, and (c) identify the transport mechanisms involved in iontophoretic transport across the palate. The histology study suggests that bovine and human palates have similar cornified epithelium structures; bovine palate could be a model tissue of human hard palate for drug delivery studies.

A profilometry-based dentifrice abrasion Method for V8 brushing machines. Part I: Introduction to RDA-PE.

Objective: This paper describes the development and standardization of a profilometry-based method for assessment of dentifrice abrasivity called Radioactive Dentin Abrasivity - Profilometry Equivalent (RDA-PE).

Methods: Human dentine substrates are mounted in acrylic blocks of precise standardized dimensions, permitting mounting and brushing in V8 brushing machines. Dentin blocks are masked to create an area of "contact brushing.

Comparative bioavailability and antimicrobial activity of cetylpyridinium chloride mouthrinses in vitro and in vivo.

Purpose: Commercialized cetylpyridinium chloride (CPC) mouthrinses were compared for antimicrobial substantivity/bioavailability in an in vitro disk retention assay (DRA) and clinical antimicrobial activity in vivo in the plaque glycolysis and regrowth method (PGRM).

Methods: Formulations compared in this testing included commercially available CPC mouthrinses: Crest Pro Health (CPH), (containing 700 ppm formulated CPC); Colgate Total Puerto Rico (CT450), (containing 450 ppm formulated CPC); Colgate Total US (CT750), (containing 750 ppm formulated CPC); and Scope Mouthwash (SCP), (containing 450 ppm formulated CPC). A water control (CTR) was included in one of the PGRM clinical trials.

Depth profile analysis of non-specific fluorescence and color of tooth tissues after peroxide bleaching.

Purpose: To examine laboratory changes of endogenous non-specific fluorescence and color throughout subsurface of tooth structures prior to and following peroxide bleaching.

Methods: Extracted human teeth were cross sectioned and mounted on glass slides. Cross sections were examined for internal color (digital camera) and nonspecific fluorescence (microRaman spectroscopy) throughout the tooth structure at specified locations.

Plaque levels of patients with fixed orthodontic appliances measured by digital plaque image analysis.

Introduction: A digital plaque image analysis system was developed to objectively assess dental plaque formation and coverage in patients treated with fixed orthodontic appliances.

Methods: The technique was used to assess plaque levels of 52 patients undergoing treatment with fixed appliances in the Department of Orthodontics at Johannes Gutenberg University in Mainz, Germany.

Results: Plaque levels ranged from 5.

Construction and purification of His-tagged staphylococcal ArsB protein, an integral membrane protein that is involved in arsenical salt resistance.

Bacterial resistance to arsenical salts encoded on plasmid pI258 occurs by active extrusion of toxic oxyanions from cells of Staphylococcus aureus. The operon encodes for three gene products: ArsR, ArsB and ArsC. The gene product of arsB is an integral membrane protein and it is sufficient to provide resistance to arsenite and antimonite.

Effect of an oscillating rotating power toothbrush on plaque removal and regrowth.

Purpose: To measure the effectiveness of an oscillating rotating power toothbrush as compared to a manual toothbrush.

Methods: 17 subjects were preliminarily assigned commercial tubes of Crest Cavity Protection (CCP) dentifrice and an Oral-B manual toothbrush (P35) with instructions for bid brushing morning and evening. Subjects remained on CCP dentifrice for 2 weeks during which they were imaged on 6 days (three each week) including daily assessments of morning plaque levels before brushing (AM), morning plaque levels after brushing (PB) and afternoon plaque levels allowing for regrowth (PM).

Lynamicins A-E, chlorinated bisindole pyrrole antibiotics from a novel marine actinomycete.

A series of chlorinated bisindole pyrroles, lynamicins A-E (1-5), was discovered from a novel marine actinomycete, NPS12745, which was isolated from a marine sediment collected off the coast of San Diego, California. Close to full length 16S rRNA sequence analysis indicated that NPS12745 is a novel strain of a recently described marine actinomycete with the proposed genus name Marinispora. The antimicrobial spectrum of these compounds was evaluated against a panel of 11 pathogens, which demonstrated that these substances possess broad-spectrum activity against both Gram-positive and Gram-negative organisms.

In vivo antiplaque efficacy of combined antimicrobial dentifrice and rinse hygiene regimens.

Purpose: To evaluate using digital plaque image analysis the antiplaque efficacy of oral care regimens including use of antimicrobial toothpaste in combination with antimicrobial mouthrinse.

Methods: 16 subjects completed the study protocol including: (1) initial treatment phase, all subjects used a standard sodium fluoride dentifrice with 2x/day brushing, (2) second treatment phase, subjects were randomized to two treatment groups: stannous fluoride/sodium hexametaphosphate dentifrice or sodium fluoride triclosan/copolymer dentifrice; (3) third treatment phase, the group using stannous fluoride dentifrice rinsed with alcohol-free cetylpyridinium chloride mouthrinse and the group using triclosan dentifrice rinsed with essential oil mouthrinse. During each phase, plaque levels were assessed in the morning before toothbrushing (AM), post-brushing in the morning (PB) and in the afternoon (PM).

Effect of bleaching treatments on microleakage of Class I restorations.

Objective: To test the effect of bleaching agents on microleakage of composite restorations.

Methods: Sixty extracted human molar class I cavities were restored using Scotchbond 1 and Filtek Z250 composite according to the manufacturer's instructions. The teeth were randomly divided into four groups (n = 15 each).

The effects of high concentration tooth whitening bleaches on microleakage of Class V composite restorations.

Objective: To explore the effects of high-concentration hydrogen peroxide bleaching agents on the microleakage of composite restorations.

Methods: In 60 extracted human molars, Class V restorations were prepared with Scotchbond 1/Filtek Z250 composite. Teeth were randomly divided into four groups: (1) no bleaching; (2) bleaching with 14% hydrogen peroxide gel from Crest Whitestrips; (3) bleaching with 20% carbamide peroxide gel from Opalescence PF 20; and (4) bleaching with 38% hydrogen peroxide gel Opalescence Xtra Boost.