Characterization of non-dialyzable constituents from cranberry juice that inhibit adhesion, co-aggregation and biofilm formation by oral bacteria.

An extract prepared from cranberry juice by dialysis known as nondialyzable material (NDM) has been shown previously to possess anti-adhesion activity toward microbial species including oral bacteria, uropathogenic Escherichia coli and Helicobacter pylori. Bioassay-guided fractionation of cranberry NDM was therefore undertaken to identify the anti-adhesive constituents. An aqueous acetone-soluble fraction (NDMac) obtained from Sephadex LH-20 inhibited adhesion-linked activities by oral bacteria, including co-aggregation of oral bacteria Fusobacterium nucleatum with Streptococcus sanguinis or Porphyromonas gingivalis, and biofilm formation by Streptococcus mutans. Analysis of NDMac and subsequent subfractions by MALDI-TOF MS and 1H NMR revealed the presence of A-type proanthocyanidin oligomers (PACs) of 3-6 degrees of polymerization composed of (epi)catechin units, with some (epi)gallocatechin and anthocyanin units also present, as well as quercetin derivatives. Subfractions containing putative xyloglucans in addition to the mixed polyphenols also inhibit biofilm formation by S. mutans (MIC = 125-250 µg mL-1). These studies suggest that the anti-adhesion activities of cranberry NDM on oral bacteria may arise from a combination of mixed polyphenol and non-polyphenol constituents.

Teaching mandibular implant-Supported overdentures in dental schools in North America - a survey.

INTRODUCTION: Mandibular two-implant overdentures are considered the minimum standard of care for edentulous patients and provide an excellent performance, as well as satisfaction to the patients. Dental schools are required to promote the teaching of current treatment options in order to enable students to master state-of-the-art procedures. AIMS: The purpose of this study was to examine how the theoretical and practical aspects of mandibular two-implant overdentures are taught in dental schools in North America. METHODS: Data were collected via an online questionnaire that included questions regarding the theoretical and clinical courses, surgical procedure and imaging method. RESULTS: Of 75 schools, 36 responded to the survey. Almost all the schools teach the subject theoretically, but it is not mandatory for students to perform in most of the schools. Only a minority (23%) of the mandibular dentures made by students are implant-supported. Almost all of the schools (94%) use two implants to support overdentures, and Locator abutment is used almost exclusively. The prevalent imaging for the surgical procedure is CT scans, although 30% of the schools use panoramic radiograph. None of the schools loads the implants immediately after surgery. CONCLUSION: Some clear trends are apparent in the current survey: the use of two implants, no use of bar connectors and delayed loading of the implants. It is likely that graduates will not have sufficient clinical skills and will need continuing education to be familiar with the required procedures, both surgical and prosthetic.

Testing manual dexterity using a virtual reality simulator: reliability and validity.

Virtual reality dental training simulators, unlike traditional human-based assessment, have the potential to enable consistent and reliable assessment. The purpose of this study was to determine whether a haptic simulator (IDEA Dental(®) ) could provide a reliable and valid assessment of manual dexterity. A total of 106 participants were divided into three groups differing in dental manual dexterity experience: (i) 63 dental students, (ii) 28 dentists, (iii) 14 non-dentists. The groups, which were expected to display various performance levels, were required to perform virtual drilling tasks in different geometric shapes. The following task parameters were registered: (i) Time to completion (ii) accuracy (iii) number of trials to successful completion and (iv) score provided by the simulator. The reliability of the tasks was calculated for each parameter. The simulator and its scoring algorithm showed high reliability in all the parameters measured. The simulator was able to differentiate between non-professionals and dental students or non-professionals and dentists. Our study suggests that for improved construct validity, shorter working times and more difficult tasks should be introduced. The device should also be designed to provide greater sensitivity in measuring the accuracy of the task.

Day-long reduction of oral malodor by a palatal mucoadhesive tablet containing herbal formulation.

Previous research has shown the oral malodor reducing abilities of an herbal formulation delivered using a palatal mucoadhesive tablet. The aim of the present study was to test the day-long effect of this preventive treatment on oral malodor reduction as compared with placebo and commercial mouthwash. Forty young healthy subjects (mean age, 25.8 ± 1.8 yrs, 19 females) presenting with oral malodor were randomly assigned to use one of the three tested products: herbal mucoadhesive tablets, placebo mucoadhesive tablets and a commercial mouthwash. Following baseline measurements, subjects were instructed to use the products in the evening of the same day and the following morning. Baseline and follow-up measurements were conducted in the afternoon and included odor judge scores (two judges), volatile sulfide compounds (VSC) levels using a sulfide monitor (Halimeter™) and saliva sample for ß-galactosidase activity assay. The herbal mucoadhesive tablet caused a significant reduction in malodor scores (p = 0.004), VSC levels (p = 0.002) and ß-galactosidase assay (p = 0.02) as compared to the placebo, and reduced malodor level to below the clinical threshold (mean odor judge score of 1.7). These results demonstrate the efficacy of the herbal formulation delivered using a mucoadhesive tablet for day-long prevention of oral malodor.

Host susceptibility to periodontitis: mapping murine genomic regions.

Host susceptibility to periodontal infection is controlled by genetic factors. As a step toward identifying and cloning these factors, we generated an A/J x BALB/cJ F2 mouse resource population. A genome-wide search for Quantitative Trait Loci (QTL) associated with periodontitis was performed. We aimed to quantify the phenotypic response of the progenies to periodontitis by microCT analysis, to perform a genome-wide search for QTL associated with periodontitis, and, finally, to suggest candidate genes for periodontitis. We were able to produce 408 F2 mice. All mice were co-infected with Porphyromonas gingivalis and Fusobacterium nucleatum bacteria. Six weeks following infection, alveolar bone loss was quantified by computerized tomography (microCT) technology. We found normal distribution of the phenotype, with 2 highly significant QTL on chromosomes 5 and 3. A third significant QTL was found on chromosome 1. Candidate genes were suggested, such as Toll-like receptors (TLR) 1 and 6, chemokines, and bone-remodeling genes (enamelin, ameloblastin, and amelotin). This report shows that periodontitis in mice is a polygenic trait with highly significant mapped QTL.

Towards antibacterial endodontic sealers using quaternary ammonium nanoparticles.

AIM: To change and characterize the antibacterial properties of endodontic sealers by incorporating low concentrations of insoluble antibacterial nanoparticles (IABN). METHODOLOGY: The antibacterial effect against Enterococcus faecalis was evaluated by (i) agar diffusion test (ADT), (ii) direct contact test (DCT) and (iii) scanning electron microscopy (SEM). IABN were incorporated into AH Plus (Dentsply, DeTrey Konstanz, Germany) and GuttaFlow (Coltène Whaledent, Langenau, Germany) at concentrations of 0.5%, 1% or 2% weight/weight. Bacterial growth rates were analysed using ANOVA followed by Tukey's test. RESULTS: The antibacterial tests demonstrated total bacterial growth inhibition using AH Plus samples incorporating 2% weight/weight IABN after 4 weeks (P < 0.005). DCT showed total growth inhibition of up to 6 logs in viable count in AH Plus samples incorporating IABN and up to 4 log in count in GuttaFlow incorporating IABN (P < 0.005). Significant differences were found between the unmodified sealers and the experimental groups. No antibacterial effect was observed in the ADT, indicating IABN were not diffusing into the agar. Furthermore, SEM indicated bacterial cell wall damage and lysis. CONCLUSIONS: AH Plus and GuttaFlow incorporating low concentrations of IABN exhibited significant and stable antimicrobial properties.

Involvement of autoimmunity in the pathogenesis of aggressive periodontitis.

The aim of this study was to investigate the involvement of autoimmune reactions to native and post-translationally modified extracellular matrix components in the pathogenesis of periodontitis. Sera from individuals with aggressive periodontitis (AgP, n = 25), chronic periodontitis (CP, n = 14), and gingivitis (G, n = 18) were tested for the presence of autoantibodies against: (a) native collagen type I (CI) and collagen type III (CIII); (b) CI and CIII post-translationally modified by reactive oxygen species (ROS) of the type present during inflammation; and (c) citrullinated filaggrin-derived peptides (CCP). Autoantibodies to native and ROS-modified CI and CIII as well as autoantibodies to CCP were observed exclusively in patients with AgP and not in those with CP or G. In conclusion, autoimmune reactions to native and post-translationally modified self-antigens may play a role specifically in the pathogenesis of AgP.

Potential oral health benefits of cranberry.

In the past decade, cranberry extracts have been attracting ever-growing attention by dental researchers. The potential benefits of cranberry components in reducing oral diseases, including dental caries and periodontitis, are discussed in this review. A non-dialysable cranberry fraction enriched in high molecular weight polyphenols has very promising properties with respect to cariogenic and periodontopathogenic bacteria, as well as to the host inflammatory response and enzymes that degrade the extracellular matrix. Cranberry components are potential anti-caries agents since they inhibit acid production, attachment, and biofilm formation by Streptococcus mutans. Glucan-binding proteins, extracellular enzymes, carbohydrate production, and bacterial hydrophobicity, are all affected by cranberry components. Regarding periodontal diseases, the same cranberry fraction inhibits host inflammatory responses, production, and activity of enzymes that cause the destruction of the extracellular matrix, biofilm formation, and adherence of Porphyromonas gingivalis, and proteolytic activities and coaggregation of periodontopathogens. The above-listed effects suggest that cranberry components, especially those with high molecular weight, could serve as bioactive molecules for the prevention and/or treatment of oral diseases.

Surface antibacterial properties of compomers.

AIM: This was to evaluate the antibacterial properties of four different compomers, using direct contact test (DCT) and agar diffusion test (ADT). Compomers (Polyacid Modified Composite Resin) form a group of dental restorative materials which were developed in order to improve conventional glass-ionomer and are widely used by pediatric dentists in primary dentition. Microorganisms captured under restorations or penetrating through the micro-gap at the tooth-restoration interface are the cause of secondary caries and pulpal pathology. METHODS: For the DCT, 8 samples of Freedom (SDI), F2000 (3M-ESPE), Dyract (Dentsply) and Hytac Hplitip (3M-ESPE) were placed on the sidewalls of wells in 96 microtiter plate. After polymerization, freshly grown streptococcus mutans cells (1x10(6)) were placed on the surface of each sample for one hour at 37 degrees C, fresh media was then added to each well and bacterial growth was followed for 16 hours by temperature controlled spectrophotometer. Similarly prepared samples were aged in phosphate buffered saline for 1, or 7 days and the DCT was repeated. The ADT was performed by placing samples in uniform wells punched in agar plates. RESULTS: In the DCT, freshly polymerized samples of F2000 showed the most potent antibacterial properties, while those of Hytac Hplitip showed moderate antibacterial phenomena. Dyract and Freedom did not show any antibacterial activity relative to the control material. None of the four aged materials showed antibacterial activity in the DCT after 1 or 7 days. In the ADT the halo in the bacterial lawn was measured after 48 hours and only F2000 demonstrated an inhibition zone of 2.15+/-0.3 mm. Statistics. Two way ANOVA indicated a significant difference in the growth rate of bacteria placed both on the different compomers (P<0.001) and in different tested time points (P<0.001). CONCLUSION: None of the compomers tested provided significant long term antibacterial activity.

[Hi-tech trends in future dentistry--Part B: diagnostic and therapeutic technologies].

The technology advance and the growing amount of knowledge had a great impact on dental practice for the last decade. The prominent change began with digital revolution presenting new computed technologies and accessible communicational means for sharing literal and imaging information. Following toward the coming biotechnological revolution, dentistry will be even further changed. This article presents dental innovations of Israeli Hi-Tech companies, sorted into two groups. Part A of the article discussed the area of computed imaging systems for educational purposes, diagnostic and treatment. While part B presents other diagnostic or therapeutic technologies. However, because some of the described technologies are still on their R&D (Research and Development) phases, they are not commercialized yet in the market.

[Hi-tech trends in future dentistry--part A: computerized technologies].

Growing knowledge and information in the field of dentistry has had a great impact on dental education, management and practice. A prominent change is the digital revolution, which presents new computed technologies and accessible means of communication for sharing written and visual information. Biotechnology, yet another innovated field, will change dentistry even further. This article presents dental innovations forwarded by Israeli Hi-Tech companies. An overview of some advances in technology in the field of dentistry is presented. Part of the described technologies is in R&D phase, part is under preliminary clinical evaluation, and a few have undergone short-term clinical studies. Part A of the article discusses the application of computerized imaging systems to educational purposes, diagnostics and treatment; part B presents other diagnostic and therapeutic technologies.

Antibacterial properties of temporary filling materials.

The purpose of this study was to investigate the antibacterial properties of temporary fillings. The direct contact test (DCT) was used to evaluate the antibacterial properties of Revoltek LC, Tempit, Systemp inlay, and IRM. These were tested in contact with Streptococcus mutans and Enterococcus faecalis. The materials were examined immediately after setting, 1, 7, 14, and 30 days after aging in phosphate buffered saline (PBS). Statistical analysis included two-way ANOVA, one-way ANOVA, and Tukey multiple comparison. Systemp inlay, Tempit, and IRM exhibited antibacterial properties when in contact with S. mutans for at least 7 days, Tempit and IRM sustained this ability for at least 14 days. When in contact with E. faecalis Tempit and IRM were antibacterial immediately after setting, IRM sustained this ability for at least 1 day. Our study suggests that the difference in temporary filling materials may influence which microorganism will be able to invade the root canal system.

Cranberry juice constituents affect influenza virus adhesion and infectivity.

Cranberry juice contains high molecular weight materials (NDM) that inhibit bacterial adhesion to host cells as well as the co-aggregation of many oral bacteria. Because of its broad-spectrum activity, we investigated NDM's potential for inhibiting influenza virus adhesion to cells, and subsequent infectivity. Hemagglutination (HA) of red blood cells (RBC) caused by representatives of both influenza virus A subtypes (H1N1)and H3N2) and the B type was inhibited by NDM at concentrations of 125 microg/ml or lower, which is at least 20-fold lower than that usually found in cranberry juice. A dose-response effect of NDM on HA was demonstrated. The infectivity of the A and B types was significantly reduced by preincubation with NDM (250 microg/ml), as reflected by the lack of cytopathic effect on Madine-Darby canine kidney (MDCK) cells and the lack of HA activity in the media of infected cells. The effect of NDM was also tested after A or B type viruses were allowed to adsorb to and penetrate the cells. Various levels of reduction in virus tissue culture infective dose TCID50 were observed. The effect was most pronounced when NDM was added several times to the infected MDCK cells. Our cumulative findings indicate that the inhibitory effect of NDM on influenza virus adhesion and infectivity may have a therapeutic potential.

A laboratory study of the effect of calcium hydroxide mixed with iodine or electrophoretically activated copper on bacterial viability in dentinal tubules.

AIM: The aim of this laboratory study was to evaluate the ability of calcium hydroxide (CH), CH/iodine-potassium iodide (IKI) and electrophoretically activated copper to kill bacteria in dentinal tubules. METHODOLOGY: In an in vitro model of dentinal tubule infection, 42 cylindrical root specimens, prepared from freshly extracted bovine teeth were used. After removal of the smear layer, intracanal dentinal tubules were infected with Enterococcus faecalis for 3 weeks. CH alone or preparations of CH with copper or IKI were placed in the root canal for 1 week. In specimens containing copper/CH, an electrophoretic current(5 mA/5 min) was applied using two electrodes follow-ing placement of the medicament in the canal. Powder dentine samples obtained from the canal wall using ISO sizes: 025, 027, 029, 031 and 033 burs were examined for the presence of viable bacteria by inoculating agar plates and counting colony forming units (cfu). RESULTS: A significant difference was found between the experimental groups and the positive control group. CH and CH/IKI significantly (P < 0.001)reduced bacterial viability in dentinal tubules to a depth of 200 microm. Specimens with CH/IKI had significantly fewer viable bacteria than CH alone in tubules between the depths of 200-500 microm. Treatment with CH/copper and electrophoresis was most effective: specimens showed no viable bacteria in dentinal tubules to a depth of 500 microm from the root-canal space. CONCLUSIONS: IKI or electrophoretically activated copper additives can significantly improve the antibacterial properties of CH in dentinal tubules.

Bacterial penetration and proliferation in root canal dentinal tubules after applying dentin adhesives in vitro.

Endodontic treatment is aimed at eliminating infection and preventing bacterial regrowth in the root canal and dentinal tubules. In the present study the ability of two dentin adhesives to prevent bacterial penetration and subsequent proliferation in dentinal tubules was evaluated. Cylindrical root specimens prepared from freshly extracted bovine teeth were used in an in vitro model of dentinal tubule infection. After removal of the smear layer the intracanal dentinal tubules of the specimens were acid-etched and treated with either Gluma or EBS. Untreated specimens served as controls. Specimens were infected with Enterococcus faecalis and incubated in Brain Heart Infusion for 21 days. Powder dentin samples obtained from within the canal lumina, using ISO 025 to 033 burs, were examined for the presence of vital bacteria by inoculating on agar plates and counting colony-forming units. A significant difference was found between the experimental groups and the untreated group. After application with Gluma specimens showed the least viable bacteria in dentinal tubules. Data suggested that dentin adhesives reduced bacterial invasion into dentin and therefore have a potential role in endodontic treatment.

A high molecular mass constituent of cranberry juice inhibits helicobacter pylori adhesion to human gastric mucus.

Because previous studies have shown that a high molecular mass constituent of cranberry juice inhibited adhesion of Escherichia coli to epithelial cells and coaggregation of oral bacteria, we have examined its effect on the adhesion of Helicobacter pylori to immobilized human mucus and to erythrocytes. We employed three strains of H. pylori all of which bound to the mucus and agglutinated human erythrocytes via a sialic acid-specific adhesin. The results showed that a high molecular mass constituent derived from cranberry juice inhibits the sialic acid-specific adhesion of H. pylori to human gastric mucus and to human erythrocytes.

Effect of repeated closures on opening torque values in seven abutment-implant systems.

STATEMENT OF PROBLEM: Implant abutment screw joints tend to loosen under clinical conditions. During impression and prosthesis fabrication, repeated clinical closing and opening of abutment screws may cause component wear and decrease frictional fit of the mating parts, resulting in altered resistance to opening and potential for loss of preload in function. PURPOSE: This study recorded changes in opening torque values due to multiple consecutive closures at a constant torque within and between different abutment/implant (A/I) systems. MATERIAL AND METHODS: Repeated opening-closing cycles were used to simulate in vitro embedment relaxation and component wear of 7 A/I systems from 5 manufacturers. Screw opening torque values were recorded up to 200 consecutive closures at 20 N/cm. RESULTS: A progressive decrease in opening torque values was measured in all implant systems. Significant differences were found between A/I systems. Systems with morse tapered and spline connections consistently maintained a higher resistance to opening force. Percentage torque loss ranged from 3% to 20% on immediate opening, and from 4.5% to 36% for average of first 30 opening/closing cycles. CONCLUSION: Repeated opening and closing of implant abutment screws caused progressive loss of torque retention with variations between systems. This was probably due to a decrease in the coefficient of friction between the mating components.

Improving fissure sealant quality: mechanical preparation and filling level.

OBJECTIVE: To assess the effect of different modes of fissure preparation and filling level on the quality of pits and fissure sealants. METHODS: Various modes of fissure preparation in combination with two filling levels were examined. A total of 90 caries-free extracted human molar teeth were divided into three groups according to fissure preparation: (a) no mechanical preparation; (b) mechanical preparation with a round carbide bur; and (c) mechanical preparation with a tapered fissure diamond bur. All fissures were acid-etched and each group was subdivided according to filling level, either to the border or overfilled, using Helioseal (Vivadent, Schaan, Lichtenstein) as a sealant material. A modified microleakage assay was performed, combining occlusal loading and thermocycling, prior to staining with 0.5% Basic Fuchsin. After sectioning, teeth were examined and photographed in a reflected light microscope, sealant retention was observed and recorded. Microleakage and sealant penetration depths were measured for each section. Two-way ANOVA was used for statistical analysis. RESULTS: Sealant penetration and retention were significantly improved by mechanical preparation compared to non-prepared fissures (p<0.0001), and preparation with a tapered fissure diamond bur was superior to the round carbide bur. Overfilled fissures caused significantly higher levels of microleakage (p<0.004). CONCLUSIONS: Based on the results of this in vitro study, it is suggested that fissure sealant quality may be improved by mechanical preparation, preferably with a tapered diamond bur, and filling just to the border. Overfilling of fissures should be avoided.

Attachment of Fusobacterium nucleatum PK1594 to mammalian cells and its coaggregation with periodontopathogenic bacteria are mediated by the same galactose-binding adhesin.

It has been shown that Fusobacterium nucleatum PK1594 coaggregates with Prophyromonas gingivalis PK1924 through a galactose-binding adhesin. In the present study, attachment of F. nucleatum PK1594 to a variety of mammalian cells was characterized. F. nucleatum PK1594 attached to all eukaryotic cells tested, including human buccal epithelial cells, gingival and periodontal ligament fibroblasts, HeLa cells and murine lymphocytes, macrophages, and polymorphonuclear leukocytes. These attachments were (i) inhibited by galactose, lactose and N-acetylgalactosamine and (ii) inhibited by monoclonal antibody specific for the galactose-binding adhesin of F. nucleatum PK1594. In addition, a coaggregation-defective mutant of F. nucleatum PK1594 (PK2172), which does not exhibit galactose binding activity, did not attach to the mammalian cells. Coaggregation of F. nucleatum PK1594 with P. gingivalis PK 1924 and Actinobacillus actinomycetemcomitans JP2, but not with other bacteria, showed a similar pattern with sugars, monoclonal antibody, and the adhesin-deficient mutant. The results suggest that the attachment of F. nucleatum PK1594 to mammalian cells and its coaggregation with periodontal pathogens are mediated by the same galactose-binding adhesin.

Continuous effect of pit and fissure sealing on S. mutans presence in situ.

PURPOSE: The effect of sealants on S. mutans presence in situ was investigated. METHODS: Four intact, fully erupted first permanent molars in each of 74 children, aged 6-8 years were required for inclusion in the study. Baseline examination included deft and plaque index. S. mutans presence on occlusal surfaces of the molars was evaluated, using a microbial replica method. Immediately after sealing the first permanent molars on one side, S. mutans presence in situ was re-evaluated, as well as three and six months thereafter. Three months after the initiation of the study, S. mutans presence was evaluated on the molars of the unsealed side, which were consequently sealed and re-evaluated immediately, and three months later. RESULTS: Positive correlation was found between deft scores, plaque indices and microbial replica values, at baseline. Sealing caused a significant reduction in S. mutans levels on the treated occlusal surfaces, in vivo (P < 0.001), which lasted, in most cases, up to six months. CONCLUSIONS: The data suggest that sealants enable a prolonged reduction of S. mutans presence in situ, indicating an additional prevention effect, by reducing one source of dissemination.