Randomised methodology development study to investigate plaque removal efficacy of manual toothbrushes.

OBJECTIVES: This study aimed to evaluate plaque removal efficacy of toothbrushes to guide clinical model development. METHODS: This single-centre, randomised, controlled, examiner-blind, method development study included 80 healthy participants. Over 28 days, participants brushed twice-daily using a fluoride toothpaste and one of four marketed toothbrushes: Toothbrushes A (compact head) and B (regular head): medium-hard; flat trim; end-rounded bristles; Toothbrush C: medium-hard; end-rounded bristles; silky, tapered filaments; compact head; Toothbrush D: soft; tapered filaments; compact head. Supra-gingival plaque removal was evaluated immediately after single brushing events (Days 0, 7, 28, at study centre) and following 7- and 28-days' home use via Rustogi modified Navy Plaque Index (RPI) and Turesky modified Quigley Hein Plaque Index (TPI). RESULTS: All toothbrushes provided significant plaque removal after single-brushing events with change from Day 0 pre-brushing scores on RPI ranging from -0.10 to -0.16 (p<.0001) and on TPI ranging from -0.61 to -0.89 (p<.0001). Toothbrushes A and B showed significant (p<.05) pre-brushing RPI/TPI plaque reductions after 7- (-0.04/-0.06, respectively for RPI; -0.16/-0.20, respectively for TPI) and 28-days (-0.04/-0.03, respectively for RPI; -0.20/-0.11, respectively for TPI) use versus Day 0 pre-brushing (except Toothbrush B, Day 28, non-significant TPI). There were no significant differences with Toothbrush C. Toothbrush D TPI was significantly lower at both timepoints versus Day 0 pre-brushing (p<.05). Study toothbrushes were generally well-tolerated. CONCLUSION: The observations from this study showed how various aspects of a study design could impact toothbrushes performance. These data will inform the design of future clinical studies of plaque removal efficacy using manual toothbrushes. CLINICAL SIGNIFICANCE STATEMENT: Regular effective oral hygiene can help prevent and treat gingivitis, principally via twice-daily mechanical cleaning with a toothbrush. Data generated from this methodology development study will help to identify the key aspects which impact toothbrushes' performance and understand which one would be more suitable to answer questions of scientific interest. This study provides useful information for the design of future clinical trials to assess plaque removal efficacy of manual toothbrushes and generate results to inform clinical recommendations.

Interactions of dentine desensitisers with human dentine: morphology and composition.

OBJECTIVE: To evaluate the effect of desensitising agents on human dentine morphology and composition. METHODS: Randomly assigned human coronal-dentine specimens were subjected to: (a) no treatment (smear-layer control, n=4); (b) acid etching with 6% citric acid (demineralised control, n=4); (c) treatment with desensitising agents (12 cycles of 60 s treatment with 60 s between-treatment rinsing, n=6 per agent); and (d) exposure to acidic challenge (pH 5.0 for 90 s, n=6 per agent). The tested products were: Listerine® Advanced Defence Sensitive (LADS; 1.4% potassium oxalate) mouthrinse, Colgate® Sensitive Pro-Relief™ mouthrinse, and toothpaste slurries (paste/water 1:2 wt/wt ratio) of Colgate® Sensitive Pro-Relief™ paste, Crest® Sensitive paste and Sensodyne® Repair and Protect paste. All dentine surfaces were studied by attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy, Raman microscopy and high vacuum scanning electron microscopy with energy-dispersive X-ray microanalysis (HV-SEM/EDX). RESULTS: Desensitising slurry treatments occluded tubule orifices of acid-etched dentine, creating a randomly distributed surface pattern of particle aggregates. The greatest intratubular penetration of occluding particles was found in dentine treated with LADS. The atomic ratios of Ca/N and Ca/P, and the mineral/matrix ratios increased after toothpaste-slurry treatments compared with the acid-etched dentine. However, the acidic challenge removed most surface precipitates and further demineralised these substrates. Before the acidic challenge, the surface features were least affected in specimens treated with Sensodyne® Repair and Protect. After the acidic challenge, the sub-surface occlusion features were least affected in specimens treated with LADS. CLINICAL SIGNIFICANCE: Although most tested products achieved occlusion of dentinal tubules and provided evidence of mineral deposits, the deposit formed by LADS demonstrated the greatest resistance to acidic challenge, which simulates intra-oral demineralisation phases.

Dentine sensitivity: past, present and future.

OBJECTIVE: This review defines dentine sensitivity (DS), its prevalence, its aetiology, the mechanism(s) responsible for DS, its diagnosis and its treatment. The review then examines the modes of action of various treatments for DS including potassium salts, strontium salts, bioglasses, arginine/calcium carbonate and professional treatments such as adhesives and oxalates. The methods used to evaluate the various treatment modalities are discussed, including laboratory studies and randomised controlled clinical trials. DATA SOURCES AND STUDY SELECTION: A literature search was conducted using PubMed, Ovid Medline and Cochrane reviews for information on DS and its treatments, as well as laboratory and clinical studies used to evaluate the efficacy of various DS treatments. With regard to efficacy of treatments for DS only reports of clinical studies that were randomised, controlled and blinded were reviewed. The authors offer new insights into the shortcomings of the recent systematic review of the use of oxalates for DS. CONCLUSION: The authors introduce the concept of a novel desensitising mouthrinse containing 1.4% potassium oxalate: Listerine® Advanced Defence Sensitive mouthrinse. Readers of this supplement issue of the Journal of Dentistry are invited to review the significance of managing the clinical problem of DS. They are also invited to assess data from laboratory and randomised controlled clinical studies in order to understand the advantages offered by regular use of 1.4% potassium oxalate-containing mouthrinse, Listerine Advanced Defence Sensitive, in particular its resistance to daily erosive and/or abrasive challenges.

Scardovia wiggsiae sp. nov., isolated from the human oral cavity and clinical material, and emended descriptions of the genus Scardovia and Scardovia inopinata.

Six strains of anaerobic, pleomorphic Gram-positive bacilli, isolated from the human oral cavity and an infected arm wound, were subjected to a comprehensive range of phenotypic and genotypic tests and were found to comprise a homogeneous group. 16S rRNA gene sequence analysis revealed that the isolates were most closely related to Scardovia inopinata CCUG 35729(T) (94.8-94.9 % 16S rRNA gene sequence similarity). The isolates were saccharolytic and produced acetic and lactic acids as end products of fermentation. The major fatty acids were C(16 : 0) (49.8 %) and C(18 : 1)ω9c (35.8 %). Polar lipid analysis revealed a variety of glycolipids, diphosphatidylglycerol, an unidentified phospholipid and an unidentified phosphoglycolipid. No respiratory quinones were detected. The peptidoglycan was of the type A4α L-Lys-Thr-Glu, with L-lysine partially replaced by L-ornithine. The DNA G+C content of one of the strains, C1A_55(T)(,) was 55 mol%. A novel species, Scardovia wiggsiae sp. nov., is proposed to accommodate the six isolates, with the type strain C1A_55(T) (=DSM 22547(T)=CCUG 58090(T)).

The Bifidobacterium dentium Bd1 genome sequence reflects its genetic adaptation to the human oral cavity.

Bifidobacteria, one of the relatively dominant components of the human intestinal microbiota, are considered one of the key groups of beneficial intestinal bacteria (probiotic bacteria). However, in addition to health-promoting taxa, the genus Bifidobacterium also includes Bifidobacterium dentium, an opportunistic cariogenic pathogen. The genetic basis for the ability of B. dentium to survive in the oral cavity and contribute to caries development is not understood. The genome of B. dentium Bd1, a strain isolated from dental caries, was sequenced to completion to uncover a single circular 2,636,368 base pair chromosome with 2,143 predicted open reading frames. Annotation of the genome sequence revealed multiple ways in which B. dentium has adapted to the oral environment through specialized nutrient acquisition, defences against antimicrobials, and gene products that increase fitness and competitiveness within the oral niche. B. dentium Bd1 was shown to metabolize a wide variety of carbohydrates, consistent with genome-based predictions, while colonization and persistence factors implicated in tissue adhesion, acid tolerance, and the metabolism of human saliva-derived compounds were also identified. Global transcriptome analysis demonstrated that many of the genes encoding these predicted traits are highly expressed under relevant physiological conditions. This is the first report to identify, through various genomic approaches, specific genetic adaptations of a Bifidobacterium taxon, Bifidobacterium dentium Bd1, to a lifestyle as a cariogenic microorganism in the oral cavity. In silico analysis and comparative genomic hybridization experiments clearly reveal a high level of genome conservation among various B. dentium strains. The data indicate that the genome of this opportunistic cariogen has evolved through a very limited number of horizontal gene acquisition events, highlighting the narrow boundaries that separate commensals from opportunistic pathogens.

Isolation and identification of bifidobacteriaceae from human saliva.

Bifidobacteriaceae were isolated from saliva and infected dentine by using a mupirocin-based selective medium. Of the saliva samples, 94% harbored bifids. The mean concentration (+/- the standard error) was 4.46 (+/-0.12) log(10)(CFU per ml + 1), and the predominant isolates were Bifidobacterium dentium, B. longum, Scardovia inopinata, Parascardovia denticolens, and Alloscardovia omnicolens.