pH-FISH: coupled microscale analysis of microbial identity and acid-base metabolism in complex biofilm samples.

Background: Correlative structural and chemical imaging of biofilms allows for the combined analysis of microbial identity and metabolism at the microscale. Here, we developed pH-FISH, a method that combines pH ratiometry with fluorescence in situ hybridization (FISH) in structurally intact biofilms for the coupled investigation of microbial acid metabolism and biofilm composition. Careful biofilm handling and modified sample preparation procedures for FISH allowed preservation of the three-dimensional biofilm structure throughout all processing and imaging steps.

Effect of mutanase and dextranase on biofilms of cariogenic bacteria: A systematic review of studies.

Matrix-degrading enzymes are promising non-biocidal adjuncts to dental biofilm control and caries prevention. By disrupting the biofilm matrix structure, enzymes may prevent biofilm formation or disperse established biofilms without compromising the microbial homeostasis in the mouth. This study reviewed whether treatment with mutanase and/or dextranase inhibits cariogenic biofilm growth and/or removes cariogenic biofilms .

The efficacy and safety of an enzyme-containing lozenge for dental biofilm control-a randomized controlled pilot trial.

Objectives: To evaluate the effect of daily use of a multiple-enzyme lozenge on de novo plaque formation, on gingivitis development, and on the oral microbiome composition.

Methods: This trial with two parallel arms included 24 healthy adults allocated to the Active (n = 12) or Placebo (n = 12) group. Subjects consumed one lozenge three times daily for seven days, and no oral hygiene procedures were allowed.

Combined pH ratiometry and fluorescence lectin-binding analysis (pH-FLBA) for microscopy-based analyses of biofilm pH and matrix carbohydrates.

Bacterial biofilms have a complex and heterogeneous three-dimensional architecture that is characterized by chemically and structurally distinct microenvironments. Confocal microscopy-based pH ratiometry and fluorescence lectin-binding analysis (FLBA) are well-established methods to characterize pH developments and the carbohydrate matrix architecture of biofilms at the microscale. Here, we developed a combined analysis, pH-FLBA, to concomitantly map biofilm pH and the distribution of matrix carbohydrates in bacterial biofilms while preserving the biofilm microarchitecture.

The Effect of Enzymatic Treatment with Mutanase, Beta-Glucanase, and DNase on a Saliva-Derived Biofilm Model.

Introduction: The dental biofilm matrix is an important determinant of virulence for caries development and comprises a variety of extracellular polymeric substances that contribute to biofilm stability. Enzymes that break down matrix components may be a promising approach to caries control, and in light of the compositional complexity of the dental biofilm matrix, treatment with multiple enzymes may enhance the reduction of biofilm formation compared to single enzyme therapy. The present study investigated the effect of the three matrix-degrading enzymes mutanase, beta-glucanase, and DNase, applied separately or in combinations, on biofilm prevention and removal in a saliva-derived in vitro-grown model.

A New Device for Dental Biofilm Collection Additively Manufactured by Direct Metal Laser Sintering and Vat Photopolymerization.

Dental biofilms are complex medical biofilms that cause caries, the most prevalent disease of humankind. They are typically collected using handcrafted intraoral devices with mounted carriers for biofilm growth. As the geometry of handcrafted devices is not standardized, the shear forces acting on the biofilms and the access to salivary nutrients differ between carriers.

Semi-Automated Planimetric Quantification of Dental Plaque Using an Intraoral Fluorescence Camera.

Dental plaque accumulation is quantified using clinical indices or, otherwise, the planimetric plaque index (PPI), which measures the relative area of a tooth that is covered by plaque deposits. Compared to clinical indices, the PPI has a higher discriminatory power, but traditional planimetry is a time-consuming analysis, as the plaque-covered and clean tooth areas have to be determined manually for each image using image-processing software. Here, we present a method for the semi-automated planimetric quantification of dental plaque, which allows for the rapid processing of up to 1,000 images simultaneously.

A fast and reliable method for semi-automated planimetric quantification of dental plaque in clinical trials.

Aim: To develop a simple and reproducible method for semi-automated planimetric quantification of dental plaque.

Materials And Methods: Plaque from 20 healthy volunteers was disclosed using erythrosine, and fluorescence images of the first incisors, first premolars, and first molars were recorded after 1, 7, and 14 days of de novo plaque formation. The planimetric plaque index (PPI) was determined using a semi-automated threshold-based image segmentation algorithm and compared with manually determined PPI and the Turesky modification of the Quigley-Hein plaque index (TM-QHPI).

Prevention of Initial Bacterial Attachment by Osteopontin and Other Bioactive Milk Proteins.

A considerable body of work has studied the involvement of osteopontin (OPN) in human physiology and pathology, but comparably little is known about the interaction of OPN with prokaryotic cells. Recently, bovine milk OPN has been proposed as a therapeutic agent to prevent the build-up of dental biofilms, which are responsible for the development of caries lesions. Bioactive milk proteins are among the most exciting resources for caries control, as they hamper bacterial attachment to teeth without affecting microbial homeostasis in the mouth.

Fluorescence lectin binding analysis of carbohydrate components in dental biofilms grown in situ in the presence or absence of sucrose.

Carbohydrate components, such as glycoconjugates and polysaccharides, are constituents of the dental biofilm matrix that play an important role in biofilm stability and virulence. Exopolysaccharides in Streptococcus mutans biofilms have been characterized extensively, but comparably little is known about the matrix carbohydrates in complex, in situ-grown dental biofilms. The present study employed fluorescence lectin binding analysis (FLBA) to investigate the abundance and spatial distribution of glycoconjugates/polysaccharides in biofilms (n = 306) from 10 participants, grown in situ with (SUC) and without (H2O) exposure to sucrose.

A comparison of video-based and slide-based teaching before hands-on rubber dam application: A quantitative and qualitative study.

Purpose/objectives: Instructional videos may demonstrate the execution of complex clinical procedures and the cooperation between members of the dental team better than traditional slide-based teaching materials. The aim of the present study was to compare the effect of a procedural video on student ratings to a traditional still-image-based presentation in a course on rubber dam application.

Methods: In a randomized, double-blind, parallel arm design, participants (46 dental students) completed a seven-item, five-step Likert-scale questionnaire at baseline (t1), after a video-based or slide-based demonstration of rubber dam application (t2) and after hands-on training (t3).

The impact of glass ionomer cement and composite resin on microscale pH in cariogenic biofilms and demineralization of dental tissues.

Objective: Secondary caries is among the most frequent reasons for the failure of dental restorations. Glass ionomer cement (GIC) restorations have been proposed to protect the surrounding dental tissues from demineralization through the release of fluoride and by buffering the acid attack from dental biofilms. In contrast, the lack of buffering by composite resin (CR) restorations has been suggested as a promoting factor for the development of secondary caries.

Reduction of dual-species biofilm after sonic- or ultrasonic-activated irrigation protocols: A laboratory study.

Aim: To evaluate the antibacterial effect of sonic- and ultrasonic-activated irrigation on bacterial reduction of a dual-species biofilm in root canals compared to nonactivated irrigation in a laboratory study.

Methodology: Two hundred and forty extracted human single-rooted maxillary anterior teeth were divided into two main groups (G, n = 120) according to the initial preparation size of the root canal (G1: size 25, 0.06 taper, G2: size 40, 0.

Ratiometric imaging of extracellular pH in biofilms exposed to different flow velocities and saliva film thicknesses.

Fluid flow has a prominent influence on the metabolism of surface-attached biofilms. Dental biofilms are covered by a thin saliva film that flows at different rates in different locations under stimulated and unstimulated conditions. The present study employed pH ratiometry to study the impact of different flow velocities, saliva film thicknesses and saliva concentrations on microscale pH developments in S biofilms of different age.

Root Caries Preventive Effect of Varnishes Containing Fluoride or Fluoride + Chlorhexidine/Cetylpyridinium Chloride In Vitro.

Caries preventive varnishes containing only fluoride might differ from those containing a combination of fluoride and antimicrobial components in terms of mineralization properties and their impact on the cariogenic biofilm. We compared a fluoride and a fluoride + chlorhexidine (CHX)/cetylpyridinium chloride (CPC) varnish on root caries formation in vitro. One hundred bovine root dentin samples were allocated to five groups ( = 20/group): (1) 7700 ppm fluoride varnish (Fluorprotector S (F)), (2) experimental placebo varnish for F (F-P), (3) 1400 ppm fluoride + 0.

Hands-on live demonstration vs. video-supported demonstration of an aesthetic composite restoration in undergraduate dental teaching.

Purpose/objectives: Live hands-on demonstration of dental procedures is a central format in undergraduate dental teaching. It captures the immediacy of the clinical situation and allows for direct communication between instructor and students, but it also requires an experienced instructor who is able to handle both the performed treatment and its visualization alongside the actual teaching. The aim of the present work is to compare the hands-on demonstration of a class IV composite restoration to a teaching format where the instructor guided the students through a prerecorded procedural video of the same treatment.

The whitening effect of single brushing with blue-covarine containing toothpaste-A randomized controlled trial.

Objective: To evaluate whether a blue covarine containing silica-based toothpaste promotes a whitening effect immediately after tooth brushing.

Methods: A triple-blind, parallel group, randomized design was used to compare the tooth color before and after brushing. Two silica-based toothpastes were chosen, one of them containing blue covarine (BCT) and the other one without pigment to serve as control (CT).

Probiotic Effects on Multispecies Biofilm Composition, Architecture, and Caries Activity .

While probiotics have been tested for their anti-caries effect in vitro and also clinically, there is a lack of understanding of their effects on complex dental biofilms. We assessed two probiotics, and , on a continuous-cultured model containing , and . Cariogenic biofilms were grown on bovine enamel specimens and daily challenged with or whole culture (LC/SC) or cell-free supernatant (LS/SS) or medium only (negative control, NC) ( = 21/group) for 10 days.

A 3D printed microfluidic flow-cell for microscopy analysis of in situ-grown biofilms.

Biofilm phenomena ranging from metabolic processes to attachment, detachment and quorum sensing are influenced by the fluid flow across the biofilm. A number of commercially available flow-cells allow for microscopy analysis of laboratory biofilms under flow, but there is a lack of shear controlled microfluidic devices that accommodate biofilms grown in situ on carriers or tissue samples. Therefore, we developed a flow-cell with adjustable geometry for microscopy analysis of in situ-grown biofilm samples under shear-controlled flow.

Monitoring Extracellular pH in Cross-Kingdom Biofilms using Confocal Microscopy.

Cross-kingdom biofilms consisting of both fungal and bacterial cells are involved in a variety of oral diseases, such as endodontic infections, periodontitis, mucosal infections and, most notably, early childhood caries. In all of these conditions, the pH in the biofilm matrix impacts microbe-host interactions and thus the disease progression. The present protocol describes a confocal microscopy-based method to monitor pH dynamics inside cross-kingdom biofilms comprising Candida albicans and Streptococcus mutans.

Improved pH-ratiometry for the three-dimensional mapping of pH microenvironments in biofilms under flow conditions.

Confocal microscopy-based monitoring of pH in biofilms is gaining increasing interest, as it allows for a quick assessment of horizontal pH gradients without mechanically perturbing the biofilm. Ratiometric monitoring of pH with the fluorescent dye C-SNARF-4 has been used to reliably map extracellular pH in the basal layers of biofilms, but only under static conditions. Here, we expand this methodology to measurements of vertical gradients in multispecies in vitro-grown and in situ-grown dental biofilms of different age, and to pH measurements in in vitro-grown biofilms under flow conditions.

Effect of DNase Treatment on Adhesion and Early Biofilm Formation of .

Objective: Extracellular DNA (eDNA) has been shown to be important for biofilm stability of the endodontic pathogen . In this study, we hypothesized that treatment with DNase prevents adhesion and disperses young biofilms in 96-well plates and root canals of extracted teeth.

Methods: eDNA in 96-well plates was visualized with TOTO-1®.

A confocal microscopy based method to monitor extracellular pH in fungal biofilms.

pH in fungal biofilms is important for a variety of fungal infections and industrial applications involving fungal biofilms, but to date, it has never been measured directly inside the biofilm matrix. In the present study, a new methodology was developed allowing for confocal microscopy based monitoring of extracellular pH inside fungal biofilms. Monospecies biofilms of Aspergillus fumigatus, Candida albicans, Candida dubliniensis and Cryptococcus neoformans were stained with the pH dependent ratiometric probe C-SNARF-4, imaged with a confocal microscope, and a digital image analysis procedure was developed to determine pH in the extracellular matrix.