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A rapid, sensitive, and specific colorimetric biosensor based on the use of magnetic nanoparticles (MNPs) was designed for the detection of Pseudomonas aeruginosa in clinical samples. The biosensing platform was based on the measurement of P. aeruginosa proteolytic activity using a specific protease substrate. At the N-terminus, this substrate was covalently bound to MNPs and was linked to a gold sensor surface via cystine at the C-terminus of the substrates. The golden sensor appears black to naked eyes because of the coverage of the MNPs. However, upon proteolysis, the cleaved peptide-MNP moieties will be attracted by an external magnet, revealing the golden color of the sensor surface, which can be observed by the naked eye. In vitro, the biosensor was able to detect specifically and quantitatively the presence of P. aeruginosa with a detection limit of 102 cfu/mL in less than 1 min. The colorimetric biosensor was used to test its ability to detect in situ P. aeruginosa in clinical isolates from patients. This biochip is anticipated to be useful as a rapid point-of-care device for the diagnosis of P. aeruginosa-related infections.

Tijdens parodontale ontstekingen sijpelen verschillende stoffen van zowel de gastheer als bacteriële oorsprong naar de gingivale creviculaire vloeistof (GCV) en speeksel. Deze stoffen, zoals eiwitten en peptiden, dienen daardoor als biomarkers van het onstekingsproces. Met behulp van gevoelige en geavanceerde laboratoriumtechnieken is de rol van al deze biomarkers inmiddels in kaart gebracht. Maar de hoge kosten, complexiteit en lastige interpretatie van de gevonden resultaten werken vaak belemmerend voor de implementatie van biomarkers voor diagnostische doeleinden in de tandheelkundige praktijk. Bepaalde speekselenzymen, de proteasen, kunnen fungeren als biomarkers en hebben interessante eigenschappen voor het bedrijven van snelle diagnostiek aan de stoel. De aanwezigheid of activiteit van een protease kan namelijk op een eenvoudige en snelle, biochemische manier worden aangetoond, bijvoorbeeld door kleurverandering. Omdat ook andere processen in de mond van invloed zijn op de testuitslag zijn dergelijke testen vooral bruikbaar als onderdeel van een uitgebreider diagnostisch onderzoek.

Despite continuous exposure to environmental pathogens, injured mucosa within the oral cavity heals faster and almost scar free compared with skin. Saliva is thought to be one of the main contributing factors. Saliva may possibly also stimulate skin wound healing. If so, it would provide a novel therapy for treating skin wounds, for example, burns. This study aims to investigate the therapeutic wound healing potential of human saliva in vitro. Human saliva from healthy volunteers was filter sterilized before use. Two different in vitro wound models were investigated: (a) open wounds represented by 2D skin and gingiva cultures were used to assess fibroblast and keratinocyte migration and proliferation and (b) blister wounds represented by introducing freeze blisters into organotypic reconstructed human skin and gingiva. Re‐epithelialization and differentiation (keratin K10, K13, K17 expression) under the blister and inflammatory wound healing mediator secretion was assessed. Saliva‐stimulated migration of skin and oral mucosa fibroblasts and keratinocytes, but only fibroblast proliferation. Topical saliva application to the blister wound on reconstructed skin did not stimulate re‐epithelization because the blister wound contained a dense impenetrable dead epidermal layer. Saliva did promote an innate inflammatory response (increased CCL20, IL‐6, and CXCL‐8 secretion) when applied topically to the flanking viable areas of both wounded reconstructed human skin and oral mucosa without altering the skin specific keratin differentiation profile. Our results show that human saliva can stimulate oral and skin wound closure and an inflammatory response. Saliva is therefore a potential novel therapeutic for treating open skin wounds.

Melioidosis is a severe disease caused by Burkholderia pseudomallei. The biofilm of B. pseudomallei acquires resistance to several antibiotics and may be related to relapse in melioidosis patients. Here, the killing activity of antimicrobial peptides (LL-37, LL-31) and the D-enantiomers (D-LL-37, D-LL-31) in combination with ceftazidime (CAZ) against B. pseudomallei 1026b, H777 and a biofilm mutant M10, derived from H777 grown under biofilm-stimulating conditions was observed. Using static conditions, D-LL-31 exhibited the strongest killing activity against the three isolates in a dose-dependent manner. IC50 values for D-LL-31 ranged from 1 to 6 µM, for isolates M10, H777, and 1026b, respectively. Moreover, D-LL-31 combined with CAZ synergistically decreased the IC50 values of the peptide and antibiotic and caused also disruption of biofilms of B. pseudomallei 1026b under flow conditions. Thus a combination of D-LL-31 and CAZ may enhance the efficacy of the currently used antibiotic treatments against B. pseudomallei.

Dental biofilms are complex ecosystems containing many bacterial species that live in mutualistic relationships. These interactions can profoundly affect the virulence properties of the community. In this study we investigated how the production of gingipains, virulence factors from Porphyromonas gingivalis important in periodontal disease, was affected by other commonly found members of the sub-gingival microbiome.To mimic the subgingival microbiome, multispecies consortia (P. gingivalis, Fusobacterium nucleatum, Actinomyces naeslundii, Streptococus oralis, Streptococcus mitis, Streptococcus gordonii and Streptococcus cristatus, with or without Parvimonas micra) as well as dual species consortia (P. gingivalis with P. micra, S. oralis or F. nucleatum) were constructed and maintained anaerobically in 10% serum for up to seven days. The number of P. gingivalis was determined by plating on Brucella agar and the gingipain specific fluorogenic substrate BikKam-10 was used to investigate gingipain activity. The effect of secreted products from P. micra on gingipain activity was investigated by adding supernatants from P. micra to P. gingivalis cultures. The most prominent secreted proteins in the supernatant were identified using mass spectrometry.P. gingivalis was unable to grow in serum, either alone or in the presence of S. oralis or F. nucleatum. In contrast, with P. micra growth was significantly enhanced and this was associated with an increase in gingipain activity. In the multi-species consortia, the presence of P. micra caused a 13-fold increase in gingipain activity. Exposure of P. gingivalis to supernatants from P. micra for 24 h caused a 3-fold increase in gingipain activity. This effect was reduced by 43% after heat-treatment of the supernatant. Two dimensional gel electrophoresis revealed that several of the most prominent proteins in the P. micra supernatant were glycolytic enzymes. The results from this study suggests that gingipains are produced in response to a P. micra derived signalling molecule that is most likely a protein.This is the first time it has been shown that P. micra can affect P. gingivalis virulence properties. This is likely to be of significance for the development of be of periodontitis since these two microorganisms are often found together in the subgingival biofilm.

Background: During the last decade, the number of people with ≥1 tattoo has increased noticeably within the European population. Despite this, limited safety information is available for tattoo inks. Objectives: To test the skin sensitization potential of 5 tattoo inks in vitro by using reconstructed human skin (RHS) and the contact sensitization biomarker interleukin (IL)-18. Methods: Two red and 3 black tattoo inks, 1 additive (Hamamelis virginiana extract) and 1 irritant control (lactic acid) were tested. The culture medium of RHS (reconstructed epidermis on a fibroblast-populated collagen hydrogel) was supplemented with test substances in a dose-dependent manner for 24 hours, after which cytotoxicity (histology; thiazolyl blue tetrazolium bromide assay) and skin sensitization potential (IL-18 secretion; enzyme-linked immunosorbent assay) were assessed. Results: All but 1 ink showed cytotoxicity. Notably, 1 red ink and 1 black ink were able to cause an inflammatory response, indicated by substantial release of IL-18, suggesting that these inks may be contact sensitizers. Conclusions: The in vitro RHS model showed that 4 tattoo inks were cytotoxic and 2 were able to cause an inflammatory IL-18 response, indicating that an individual may develop allergic contact dermatitis when exposed to these tattoo inks, as they contain contact sensitizers.

Background: Recently, measurements of steroids like testosterone, androstenedione, cortisol and cortisone in saliva are more and more applied in diagnostics and scientific studies. This is mainly due to the simple and non-invasive collection of saliva. We aimed to evaluate the optimal way to collect saliva for steroid hormone measurement. Methods: We investigated in twenty volunteers whether there is a difference between steroid hormone concentrations in unstimulated and stimulated saliva collected while chewing, using cotton and synthetic Salivettes®, citric acid or chewing gum. Furthermore, total unstimulated saliva was compared to parotid gland saliva. Testosterone, androstenedione, cortisol and cortisone were measured using Liquid-Chromatography Tandem Mass Spectrometry (LC-MS/MS). Results: Salivary testosterone, androstenedione and cortisol concentrations were unaffected by stimulation upon mouth and tongue movements, cortisone levels were on average 16% lower. Concentrations of all hormones were lower in parotid gland saliva compared to total unstimulated saliva (on average 51%, 26%, 66% and 49% lower, for testosterone, androstenedione, cortisol and cortisone, respectively). Concentrations of testosterone as well as androstenedione were lower when using synthetic Salivettes® (58% and 41%, respectively) and were higher when using cotton Salivettes® (217% and 46%, respectively). Cortisol levels in saliva were unaffected by using Salivettes®. However, cortisol and testosterone levels were higher in with chewing gum stimulated saliva (16% and 55%, respectively). Cortisone concentrations were lower in all types of stimulations (on average 25%–35%). Conclusion: The way saliva is collected should be considered when analysing and interpreting salivary hormone concentrations. We advocate unstimulated saliva collection in simple polypropylene tubes for all steroid measurements.

In een veilig en welvarend land als Nederland komt kindermishandeling helaas ook voor. Sinds 2013 zijn alle organisaties en zelfstandige beroepsbeoefenaren in de gezondheidszorg wettelijk verplicht een meldcode te gebruiken bij vermoedens van huiselijk geweld en kindermishandeling. De KNMT heeft een eigen meldcode ontwikkeld met een stappenkaart met daarin 5 stappen en een afwegingskader, voor zowel kindermishandeling als volwassengeweld. Sinds 2 juli 2018 kunnen tandartsen hiermee werken. Vanaf januari 2019 is dit verplicht. Wat moet ik weten?

H.S. Brand of the Academic Centre for Dentistry Amsterdam, and film aficionado, returns with a special review of ‘A Christmas story 2’, a film directed by Brian Levant in 2012.

Speeksel is een veelzijdige vloeistof die rijk is aan moleculen en micro-organismen. Zo bevat speeksel antimicrobiële eiwitten die schadelijke micro-organismen in toom houden, buffers die de etsende werking van zuren op tandglazuur beperken en glycoproteïnen − mucinen − die bijdragen aan de viscositeit van speeksel en de smering van de mondholte. Kortom, speeksel speelt een cruciale rol in de handhaving van een gezonde mond. Doordat speeksel gemakkelijk en veilig te verzamelen is, en rijk is aan analyten, is het een aantrekkelijke vloeistof voor diagnostiek. De bepaling van de hoeveelheid speeksel kan al helpen bij het vaststellen van monddroogte. Anderzijds kan de analyse van verschillende biomarkers helpen bij het vinden van de juiste remedies voor zowel orale als voor sommige systemische ziekten. Om diagnostiek in de praktijk mogelijk te maken, is er in groeiende mate belangstelling voor handzame tests. In dit artikel wordt de huidige kennis van speekseldiagnostiek in zowel de mondzorgkundige praktijk als daarbuiten besproken.

Het syndroom van Sjörgren (SS) is een auto-immuunziekte waarbij de exocriene klieren zijn betrokken. Met name de traan-en speekselklieren zijn vaak aangedaan. een droge mond en ogen zijn hiervan het gevolg. Tevens zijn er vaak ook aspecifieke symptonen aanwezig, zoals algehele malaise en vermoeidheid. SS komt vooral voor bij vrouwen - met een vrouw-manration van 9:1 - en kan op elke leeftijd voorkomen. Tandartsen en mondhygiënisten spelen een zeer belangrijke rol in het zo gezond mogelijk houden van de mond en dentitie van deze patiënten. In dit artikel wordt besproken wat het syndroom van Sjörgren is. Ook besteden we aandacht aan hoe het kan worden vastgesteld of een mond droog is.

De mondgezondheid van (top)sporters is slechter dan die van vergelijkbare niet-sporters. Een van de oorzaken hiervan is monddroogte. Intensieve sportbeoefening veroorzaakt op verschillende manieren monddroogte. Door intensief sporten stijgt de lichaamstemperatuur tot boven de 39 graden. Dit gaat gepaard met transpireren, wat leidt tot verlies van water en zouten. Wanneer die niet worden aangevuld, treedt uitdroging op, wat gepaard gaat met een dorstgevoel, een droge mond en een lagere speekselproductie. Ten tweede veroorzaakt mondademhaling tijdens intensief sporten een gevoel van monddroogte. Ten derde veroorzaakt sportbeoefening een toename van de eiwit- en slijmproductie. Dit leidt tot dik, slijmerig speeksel, wat ook een droog gevoel kan geven. Naast de sport zelf veroorzaken diverse prestatiebevorderende middelen zoals amfetaminen, diuretica en astmamedicijnen een droge mond. Monddroogte maakt sporters gevoeliger voor cariës en tanderosie. Daarom is de consumptie van sportdranken, die zuur en suiker bevatten, niet aan te bevelen tijdens het sporten.

In onze maatschappij hebben ‘alle’ kwetsbare ouderen fundamenteel recht op kwalitatieve en toegankelijke mond(gezondheids)zorg. De mondhygiëne en mondzorg van ouderen in zorginstellingen in Nederland, België (Vlaanderen) en Europa baart echter grote zorgen. Juist nu dient de overheid dringende en strategische beslissingen te nemen om dit confronterende probleem op te lossen. Het aanbod zorgverleners daalt, de financiële middelen nemen af en de doelgroep neemt juist toe door vergrijzing. Wat zijn mogelijke oplossingen?

Objective Polymorphonuclear neutrophils (PMNs) are the most abundant innate immune cells and are also important effectors in the maintenance of oral health. However, little is known about the effects of saliva on the PMN. We therefore aimed to investigate the effect of saliva on the PMNs’ morphology and functioning. Design Effect of saliva on the membrane integrity of PMNs isolated from blood was evaluated with FACS using Annexin V (apoptosis marker) and propidum iodide (membrane integrity marker). The effect on cell morphology was examined using transmission electron imaging. Binding and phagocytosis of the oral bacterium Fusobacterium nucleatum by PMNs was analysed by FACS. Reactive oxygen species (ROS) production was measured with chemiluminescence. Results Incubation with saliva for 60 min had no detectable effects on the membrane integrity or the morphology of PMNs. In contrast, preincubation of F. nucleatum with saliva inhibited its subsequent interaction with PMNs, resulting in a diminished production of ROS. Conclusions Saliva does not impair the function of PMNs. However, interaction of salivary components with F. nucleatum may affect their recognition by PMNs resulting in a diminished functional response.

Yersinia pestis is the causative agent of plague. As adequate antibiotic treatment falls short and currently no effective vaccine is available, alternative therapeutic strategies are needed. In order to contribute to solving this problem we investigated the therapeutic potential of the peptide construct LFchimera against the safer-to-handle Y. pestis simulants Yersinia enterocolitica and Yersinia pseudotuberculosis in vitro. LFchimera is a heterodimeric peptide construct mimicking two antimicrobial domains of bovine lactoferrin, i.e. lactoferrampin and lactoferricin. LFchimera has been shown to be a potent antimicrobial peptide against a variety of bacteria in vitro and in vivo. Also Y. enterocolitica and Y. pseudotuberculosis have been shown to be susceptible for LFchimera in vitro. As Yersiniae spp. adhere to and invade host cells upon infection, we here investigated the effects of LFchimera on these processes. It was found that LFchimera has the capacity to inhibit host-cell invasion by Yersiniae spp. in vitro. This effect appeared to be host-cell mediated, not bacteria-mediated. Furthermore it was found that exposure of human HeLa epithelial cells to both LFchimera and the bacterial strains evoked a pro-inflammatory cytokine release from the cells in vitro.

ObjectivesTo assess the effect of sialendoscopy of the major salivary glands on salivary flow and xerostomia in patients with Sjögren’s syndrome (SS).MethodsForty-nine patients with SS were randomly assigned to a control group (n=15) and two intervention groups: irrigation of the major glands with saline (n=16) or with saline followed by triamcinolone acetonide (TA) in saline (n=18). Unstimulated whole saliva flow (UWS), chewing-stimulated whole saliva flow (SWS), citric acid-stimulated parotid flow (SPF), Clinical Oral Dryness Score (CODS), Xerostomia Inventory (XI) score and the European League Against Rheumatism (EULAR) SS Patient-Reported Index (ESSPRI) were obtained 1 week (T0) before, and 1 (T1), 8 (T8), 16 (T16) and 24 (T24) weeks after sialendoscopy.ResultsMedian baseline UWS, SWS and SPF scores were 0.14, 0.46 and 0.22 mL/min, respectively. After intervention, significant increases in UWS and SWS were observed in the saline group (at T8 (P=0.013) and T24 (P=0.004)) and the saline/TA group (at T24 (P=0.03) and T=16 (P=0.035)). SPF was increased significantly in the saline/TA group at T24 (P=0.03). XI scores declined after sialendoscopy in both intervention groups. Compared with the control group, CODS, XI and ESSPRI improved in the intervention groups. UWS, SWS and SPF were higher in the intervention groups compared with the control group, but these differences were not significant except for SPF in the saline/TA group at T24 (P=0.005).ConclusionsIrrigation of the major salivary glands in patients with SS enhances salivary flow and reduces xerostomia up to 6 months after sialendoscopy.

The purpose of this study was to explore the association of the clinical oral dryness score (CODS) with salivary flow rates, xerostomia inventory (XI), and bother index (BI). 147 patients were screened using CODS, which determined 10 features of oral dryness. Each feature contributed 1 point, and the total score varied from 0 to 10. Unstimulated (UWS), chewing-stimulated (CH-SWS) and acid-stimulated (A-SWS) whole salivary flows and the XI and BI were measured. Associations were explored with a bootstrapped Spearman rank correlation test (1000 × bootstrapping). Based on unstimulated salivary flow, 55 patients were classified as hyposalivators, 31 as low salivators, 48 as normosalivators and 13 as high salivators. Median CODS in the hyposalivation group was 5 (IQR 3–6) compared with 3 (IQR 2–5) in the low salivation group, 2 (IQR 1–4) in the normal salivation group and 2 (IQR 1–2.5) in the high salivation group. Significant associations between CODS and the other parameters were only found in the hyposalivation group between CODS and UWS (ρ(53) = − 0.513; p

Steeds meer gaat de aandacht bij cariësmanagement uit naar de begeleiding van kinderen bij systematische plaqueverwijdering. Ouders worden gemotiveerd de tanden van hun kinderen te poetsen, waarbij de eigen verantwoordelijkheid benadrukt wordt. Toch zijn er nog veel kinderen die we zien met (diepe) carieuze laesies die te laat adequate tandheelkundige zorg in welk vorm dan ook krijgen. Als er langdurig periapicale ontstekingen in de melkdentitie zijn, is er ook in de huidige tijd nog een kans dat blijvende elementen schade oplopen. Opvolgers worden gezien met hypoplasieën, een hoger cariësrisico of zelfs malformatie van de apex. Vandaar dat ook (diep)carieuze melkelementen adequate zorg verdienen.

Bacillus anthracis secretes a three component exotoxin-complex, which contributes to anthrax pathogenesis. Formation of this complex starts with the binding of protective antigen (PA) to its cellular receptor. In this study, we report that PA is a calcium-dependent serine protease and that the protein potentially uses this proteolytic activity for receptor binding. Additionally our findings shed new light on previous research describing the inhibition of anthrax toxins and exotoxin formation. Importantly, inhibition of the proteolytic activity of protective antigen could be a novel therapeutic strategy in fighting B. anthracis-related infections.

Het behandelen van kinderen vraagt veel van de tandarts. Tal van aanbevelingen zijn er hoe behandelingen makkelijker te laten verlopen. Hoe kun je het beste communiceren, welke behandeltechnieken zijn toepasbaar, welke mogelijkheden zijn er voor pijnbestrijding, enz. Maar heeft u zich eigenlijk wel eens afgevraagd waarom kinderen bang voor u zijn? Komt dat door onze goed bedoelde acties, hadden we het misschien anders moeten aanpakken? Wellicht herkent u iets van de hieronder uit de kindermond opgetekende verhalen.

In dit onderzoek werd de prevalentie van musculoskelettale klachten onder tandartsen en tandheelkundestudenten in Nederland geïnventariseerd door middel van 2 overeenkomstige web-enquêtes. Hieraan namen 196 (25% respons) tandartsen en 359 (40% respons) studenten deel. Van de tandartsen gaf 80% en van de studenten gaf 95% aan de afgelopen 12 maanden last te hebben gehad van spieren en gewrichten, waarbij vooral nek, schouders en onderrug werden genoemd. Studenten meldden daarnaast ook vaak klachten in de bovenrug. Door vrouwelijke studenten werden veel lichamelijke klachten vaker genoemd dan door de mannelijke studenten. Bij tandartsen werd daarentegen geen geslachtsverschil waargenomen, maar bleek ervaren stress een belangrijke risicofactor op het ontwikkelen van musculoskelettale klachten. Gezien de negatieve effecten op de beroepsuitoefening is nader onderzoek naar de preventie van musculoskelettale aandoeningen dringend gewenst, in het bijzonder wat betreft de doelmatigheid van (postacademisch) onderwijs en beroepsmatige voorlichting op dat gebied.

Objectives: The aberrant expression of mucins and mucin-type carbohydrates has been described in many types of cancer, including mucoepidermoid carcinoma (MEC), a malignant salivary gland tumor. In this study, we examined the aberrant expression patterns of mucins (MUC1, MUC4, MUC5AC and MUC5B), simple mucin-type carbohydrate antigens (Tn, sialyl-Tn and T) and mature carbohydrate antigens (Lewisa and sulfo-Lewisa antigens) in MEC originating from the parotid gland, which normally does not secrete mucins. Design: We conducted an immunohistochemical study to investigate the presence of mucins and carbohydrates in 24 MEC samples originating from the parotid gland and in surrounding normal tissue of the same gland in comparison 6 samples of normal salivary glands. The expression levels were compared with respect to the histological grading. Furthermore, 24 MEC samples from non-parotid salivary glands were included. Results: We observed loss of topology of membrane-bound MUC1 and MUC4, and de novo expression of MUC5AC, MUC5B and sialyl-Tn in MEC that originated in the parotid gland. Furthermore, mucins MUC1, MUC4 and carbohydrate antigens Tn, sialyl-Tn, T, Lewisa and sulfo-Lewisa were overexpressed in MEC samples compared to surrounding normal salivary gland tissues. MUC1 was expressed in both low- and high grade MECs, whereas MUC4 was not expressed in high grade MECs of the parotid gland. Conclusion: During the development of MEC in the parotid gland, the genes for gel-forming secretory mucins are switched on. Besides these MEC tissues overexpress short oligosaccharides, suggesting that the glycosylation machinery is altered.

The biochemical composition of articaine differs from other amide anaesthetics. The lipophilic part of articaine consists of a thiophene ring, whereas other amide anaesthetics contain a benzene ring. When used correctly, local anaesthetics are remarkably safe. However, all local anaesthetics are potentially neurotoxic. In rare cases a prolonged abnormal perception/sensation may be present after the expected duration of action (paraesthesia). In several countries retrospective studies have been conducted that examined the incidence of persistent paraesthesia after the use of local anaesthetics. In most studies the number of paraesthesia cases after the use of articaine was higher than the market share of this anaesthetic. In animal studies and in cell culture experiments, however, articaine did not have a higher toxicity compared to other amide anaesthetics. Further studies of the cause of paraesthesia after administration of local anaesthetics seem to be warranted.

Objectives. This study aimed to assess the impact of celiac disease (CD) on oral health and xerostomia. Study Design. Members of the Dutch Celiac Society (n = 5522) were invited to complete an online questionnaire based on the Oral Health Impact Profile 14 (OHIP-14) and Xerostomia Inventory (XI). Acquaintances and partners of the CD respondents served as the comparison group. In total, data of 740 patients with CD and 270 comparison participants were evaluated. Results. The median age of the responding patients with CD (55 years) was similar to the median age in the comparison group (53 years). Oral health problems, including aphthous stomatitis, painful mouth, and gingival problems, were more frequently reported by patients with CD. Mean OHIP-14 score (4.9 vs 2.6; P Conclusions. This study showed that oral health problems are more commonly experienced in adult patients with CD than in the comparison group. Collaboration between dentists and gastroenterologists is recommended to increase detection of undiagnosed CD.

In het onderzoek, dat aan de basis lag van het proefschrift ‘Het effect van speeksel op de kolonisatie van mondbacteriën’ uit 1992, werd aggregatie of klontering van mondbacteriën door speeksel onderzocht. Dit voorkomt kolonisatie van bacteriën in de mond. Er bestaan grote individuele verschillen in aggregatie-activiteit van speeksel, die mede worden bepaald door de bloedgroep van de donor. Bloedgroepantigenen komen, behalve op rode bloedcellen, ook voor op speekseleiwitten. Dit geldt echter niet voor iedereen: alleen bij zogenoemde secretors komen deze bloedgroepantigenen op speekseleiwitten voor. Non-secretors aggregeerden bacteriën slechter dan secretors. In later onderzoek werden non-secretors geassocieerd met een verhoogd cariësrisico. In vervolgonderzoek werd gevonden dat het complementsysteem, een afweersysteem in bloed, werd geactiveerd door speeksel van secretors, maar niet van non-secretors. Zo blijkt de afweer in de mond te worden beïnvloed door de bloedgroep en secretorstatus, maar op een andere manier dan aanvankelijk werd gedacht.

The Scavenger Receptor Cysteine-Rich (SRCR) proteins are an archaic group of proteins characterized by the presence of multiple SRCR domains. They are membrane-bound or secreted proteins, which are generally related to host defense systems in animals. Deleted in Malignant Brain Tumors 1 (DMBT1) is a SRCR protein which is secreted in mucosal fluids and involved in host defense by pathogen binding by its SRCR domains. Genetic polymorphism within DMBT1 leads to DMBT1-alleles giving rise to polypeptides with interindividually different numbers of SRCR domains, ranging from 8 SRCR domains (encoded by 6 kb DMBT1 variant) to 13 SRCR domains (encoded by the 8 kb DMBT1 variant). In the present study, we have investigated whether reduction from 13 to 8 amino-terminal SRCR domains leads to reduction of bacterial binding. The 6 kb variant bound ~20–45% less bacteria compared to the 8 kb variant. These results support the hypothesis that genetic variation in DMBT1 may influence microbial defense.

Giardia intestinalis is the most common infectious protozoan parasite in children. Despite the effectiveness of some drugs, the disease remains a major worldwide problem. Consequently, the search for new treatments is important for disease eradication. Biological molecules with antimicrobial properties represent a promising alternative to combat pathogens. Bovine lactoferrin (bLF) is a key component of the innate host defense system, and its peptides have exhibited strong antimicrobial activity. Based on these properties, we evaluated the parasiticidal activity of these peptides on G. intestinalis. Trophozoites were incubated with different peptide concentrations for different periods of time, and the growth or viability was determined by carboxyfluorescein-succinimidyl-diacetate-ester (CFDA) and propidium iodide (PI) staining. Endocytosis of peptides was investigated by confocal microscopy, damage was analyzed by transmission and scanning electron microscopy, and the type of programmed cell death was analyzed by flow cytometry. Our results showed that the LF peptides had giardicidal activity. The LF peptides interacted with G. intestinalis and exposure to LF peptides correlated with an increase in the granularity and vacuolization of the cytoplasm. Additionally, the formation of pores, extensive membrane disruption, and programmed cell death was observed in trophozoites treated with LF peptides. Our results demonstrate that LF peptides exhibit potent in vitro antigiardial activity.

Ulcerative colitis is a rather common inflammatory bowel disease, especially in the industrialised world. A limited number of studies have reported the prevalence of oral signs and symptoms in these patients, and widely varying prevalence rates have been reported ranging from 2 to 34%. Pyostomatitis vegetans is the most pathognomonic oral sign but also other abnormalities as oral ulcerations, caries and periodontitis are more often seen in patients with ulcerative colitis. In this review we describe the oral manifestations of ulcerative colitis and their potential dental implications.

Introduction: The Porcine Myeloid Antibacterial Peptide (PMAP)-23 is a porcine host defence peptide with strong antibacterial activity against Gram-positive and Gram-negative bacteria, and fungi. Objective: PMAP-23 and truncated/mutated derivatives were tested for antibacterial and immunomodulatory activities to determine core elements of the peptide required for functionality. Methods: PMAP-23 and truncated and/or mutated derivatives were synthesized. Antibacterial activity against Gram positive and negative bacteria was determined using colony counting assays. Cytotoxicity was measured against red blood cells and epithelial cells. Peptide induced cytokine production of epithelial cells was determined by ELISA. LPS neutralization was measured using isothermal titration calorimetry and inhibition of LPS induced cytokine production by macrophages. The effect of peptides on phagocytosis was performed by measuring uptake of fluorescently labelled beads by porcine macrophages. Results: Truncation of the peptide did not lead to a strong reduction in antibacterial activity, but interestingly, all C-terminal truncated forms were strongly inhibited by salt addition, unlike the full length peptide or the two N-terminally truncated peptides. None of the peptides were hemolytic or toxic in concentrations up to 40 μM. Full length PMAP-23 induced IL-8 production in porcine epithelial cells, however, this activity was lost in all truncated peptides. None of the peptides bound LPS and subsequently did not inhibit LPS-induced cytokine production of monocytes. Finally, all PMAP-23 derived peptides reduced the uptake of beads by freshly isolated monocytes. Conclusion: PMAP-23 is mainly antibacterial with only limited immunomodulating capacity; the full length peptide is required for the full spectrum of activities.

Mastitis in dairy cattle is an inflammatory reaction of the udder tissue. Mastitis increases plasmin levels, leading to an increased proteolysis of milk proteins such as casein, resulting in a significant decrease in milk quality and related dairy products. Due to its key-role in mastitis, we used plasmin proteolytic activity as a biomarker for the detection of mastitis in bovine mastitic milk. Inspired by earlier studies on protease activity using mastitic milk samples, we developed a simple colorimetric assay to distinguish mastitic milk from milk derived from healthy animals. The plasmin substrate coupled to magnetic nanoparticles form a black self-assembled monolayer on a gold sensor surface. In the presence of increased levels of plasmin, the substrate is cleaved and the peptide fragment attached to the magnetic beads, will be attracted by the magnet which is present under the sensor strips revealing the golden surface. We found the area of the golden color surface proportional to plasmin activity. The sensitivity of this method was determined to be 1 ng/ml of plasmin in vitro. Next, we tested the biosensor using mastitis positive milk of which infection is confirmed by bacterial cultures. This newly developed colorimetric biosensor has high potential in applications for the diagnosis of mastitis with potential spin offs to health, food and environmental sectors.

Streptococcus pneumoniae colonizes the upper airways of children and the elderly. Colonization progresses to persistent carriage when S. pneumoniae forms biofilms, a feature required for the development of pneumococcal disease. Nasopharyngeal biofilms are structured with a matrix that includes extracellular DNA (eDNA), which is sourced from the same pneumococci and other bacteria. This eDNA also allows pneumococci to acquire new traits, including antibiotic resistance genes. In this study, we investigated the efficacy of lactoferrin (LF), at physiological concentrations found in secretions with bactericidal activity [i.e., colostrum (100 μM), tears (25 μM)], in eradicating pneumococcal biofilms from human respiratory cells. The efficacy of synthetic LF-derived peptides was also assessed. We first demonstrated that LF inhibited colonization of S. pneumoniae on human respiratory cells without affecting the viability of planktonic bacteria. LF-derived peptides were, however, bactericidal for planktonic pneumococci but they did not affect viability of pre-formed biofilms. In contrast, LF (40 and 80 μM) eradicated pneumococcal biofilms that had been pre-formed on abiotic surfaces (i.e., polystyrene) and on human pharyngeal cells, as investigated by viable counts and confocal microscopy. LF also eradicated biofilms formed by S. pneumoniae strains with resistance to multiple antibiotics. We investigated whether treatment with LF would affect the biofilm structure by analyzing eDNA. Surprisingly, in pneumococcal biofilms treated with LF, the eDNA was absent in comparison to the untreated control (∼10 μg/ml) or those treated with LF-derived peptides. EMSA assays showed that LF binds S. pneumoniae DNA and a time-course study of DNA decay demonstrated that the DNA is degraded when bound by LF. This LF-associated DNase activity inhibited acquisition of antibiotic resistance genes in both in vitro transformation assays and in a life-like bioreactor system. In conclusion, we demonstrated that LF eradicates pneumococcal-colonizing biofilms at a concentration safe for humans and identified a LF-associated DNAse activity that inhibited the acquisition of resistance.

Objective Salivary total protease and chitinase activities were measured by a broad-spectrum fluorescence resonance energy transfer approach as predictors of induction and resolution of gingival inflammation in healthy individuals by applying an experimental human gingivitis model.Methods Dental biofilm accumulated (21 days, Induction Phase) by omitting oral hygiene practices followed by a 2-week Resolution Phase to restore gingival health in an experimental gingivitis study. Plaque accumulation, as assessed by the Turesky Modification of the Quigley-Hein Plaque Index (TQHPI), and gingival inflammation, assessed using the Modified Gingival Index (MGI), scores were recorded and unstimulated saliva was collected weekly. Saliva was analysed for total protein, albumin, total protease activity and chitinase activity (n = 18)Results The TQHPI and MGI scores, as well as total protease activity, increased until day 21. After re-establishment of oral hygiene, gingival inflammation levels returned to values similar to baseline (day 0). Levels of protease activity decreased significantly, but not to baseline values. Furthermore, ‘fast’ responders, who responded immediately to plaque, exhibited significantly higher proteolytic activity throughout the experimental course than ‘slow’ responders, who showed a lagged inflammatory response.Conclusion The results indicate that differential inflammatory responses encompass inherent variations in total salivary proteolytic activities, which could be further utilised in contemporary diagnostic, prognostic and treatment modalities for periodontal diseases.

The scavenging capacity of glycoprotein DMBT1 helps defend mucosal epithelia against microbes. DMBT1 binding to multiple bacterial species involves its conserved Scavenger Receptor Cysteine-Rich (SRCR) domains, localized to a 16-mer consensus sequence peptide, SRCRP2. Previously, we showed that DMBT1 bound Pseudomonas aeruginosa pili, and inhibited twitching motility, a pilus-mediated movement important for virulence. Here, we determined molecular characteristics required for twitching motility inhibition. Heat-denatured DMBT1 lost capacity to inhibit twitching motility and showed reduced pili binding (~40%). Size-exclusion chromatography of Lys-C-digested native DMBT1 showed that only high-Mw fractions retained activity, suggesting involvement of the N-terminal containing repeated SRCR domains with glycosylated SRCR-Interspersed Domains (SIDs). However, individual or pooled consensus sequence peptides (SRCRPs 1 to 7) showed no activity and did not bind P. aeruginosa pili; nor did recombinant DMBT1 (aa 1–220) or another SRCR-rich glycoprotein, CD163. Enzymatic de-N-glycosylation of DMBT1, but not de-O-glycosylation, reduced its capacity to inhibit twitching motility (~57%), without reducing pili binding. Therefore, DMBT1 inhibition of P. aeruginosa twitching motility involves its N-glycosylation, its pili-binding capacity is insufficient, and it cannot be conferred by the SRCR bacteria-binding peptide domain, either alone or mixed with other unlinked SRCRPs, suggesting an additional mechanism for DMBT1-mediated mucosal defense.

Adjunctive use of antibiotics in periodontal treatment have limitations and disadvantages including bacterial resistance. Antimicrobial peptides (AMPs) are potential new agents that can combat bacterial infection. In this study, antimicrobial activity of different concentrations of conventional antibiotics minocycline (MH), doxycycline (DOX), and antimicrobial peptides LL-37, LL-31, Lactoferrin chimera (LFchimera) and Innate Defense Regulator Peptide 1018 (IDR-1018) against Aggregatibacter actinomycetemcomitans ATCC 43718 were determined using colony culturing assay. Subsequently, in vitro activity of the most effective drug and peptide combination was evaluated by checkerboard technique. Impact of the drug and peptide co-administration on biofilm at different stages, i.e., during adhesion and 1-day old biofilm was compared to each of the agents used alone. Results revealed that the killing effects of all AMPs range from 13-100%. In contrast, MH and DOX at 1 and 5 μM showed no killing activity and instead stimulated growth of bacteria. DOX has better killing activity than MH. LFchimera displayed the strongest killing amongst the peptides. Checkerboard technique revealed that combining DOX and LFchimera yielded synergism. Confocal laser scanning microscopy further showed that the combination of DOX and LFchimera caused significant reduction of bacterial adhesion and reduction of biomass, average biofilm thickness and substratum biofilm coverage of 1-day old biofilm compared to DOX and LFchimera alone. In conclusion, LFchimera alone and in combination with DOX exhibited strong antibacterial and anti-biofilm property against A. actinomycetemcomitans. The findings suggest that LFchimera should be considered for development as a new potential therapeutic agent that may be used as an adjunctive treatment for periodontitis.

Background Since periodontitis is bi-directionally associated with several systemic diseases, such as diabetes mellitus and cardiovascular diseases, it is important for medical professionals in a non-dental setting to be able examine their patients for symptoms of periodontitis, and urge them to visit a dentist if necessary. However, they often lack the time, knowledge and resources to do so. We aim to develop and assess “quick and easy” screening tools for periodontitis, based on self-reported oral health (SROH), demographics and/or salivary biomarkers, intended for use by medical professionals in a non-dental setting. Methods Consecutive, new patients from our outpatient clinic were recruited. A SROH questionnaire (8 questions) was conducted, followed by a 30 s oral rinse sampling protocol. A complete clinical periodontal examination provided the golden standard periodontitis classification: no/mild, moderate or severe periodontitis. Total periodontitis was defined as having either moderate or severe. Albumin and matrix metalloproteinase-8 concentrations, and chitinase and protease activities were measured in the oral rinses. Binary logistic regression analyses with backward elimination were used to create prediction models for both total and severe periodontitis. Model 1 included SROH, demographics and biomarkers. The biomarkers were omitted in the analysis for model 2, while model 3 only included the SROH questionnaire. The area under the receiver operating characteristic curves (AUROCC) provided the accuracy of each model. The regression equations were used to create scoring algorithms, composed of the remaining predictors, each with its own weight. Results Of the 156 patients participating in this study, 67% were classified with total periodontitis and 33% had severe periodontitis. The models for total periodontitis achieved an AUROCC of 0.91 for model 1, 0.88 for model 2 and 0.81 for model 3. For severe periodontitis, this was 0.89 for model 1, 0.82 for model 2 and 0.78 for model 3. The algorithm for total periodontitis (model 2), which we consider valid for the Dutch population, was applied to create a freely accessible, web-based screening tool. Conclusions The prediction models for total and severe periodontitis proved to be feasible and accurate, resulting in easily applicable screening tools, intended for a non-dental setting. Electronic supplementary material The online version of this article (10.1186/s12903-019-0784-7) contains supplementary material, which is available to authorized users.

Speeksel als medicijn klinkt misschien gek, maar de instinctieve reactie om een verwonde vinger direct in je mond steken lijkt wel degelijk een positief effect te hebben op wondgenezing. Uit onderzoek bij ratten is inderdaad gebleken dat wonden waaraan dieren gelikt hadden sneller genezen dan wonden waaraan niet gelikt werd (1). Verder is bekend dat door de aanwezigheid van speeksel, wonden in de mond sneller genezen en minder littekens vormen dan de huid (2). Deze bevinding zijn aanleiding voor een onderzoek naar de toepassing van speeksel als behandeling bij brandwonden. Dit onderzoek wordt uitgevoerd in het Academisch Centrum Tandheelkunde Amsterdam samen met het Amsterdam UMC, locatie VUmc en het brandwondencentrum van het Rode Kruis Ziekenhuis in Beverwijk.

The pupil dilation response is sensitive both to listening effort and the emotional significance of a task. We aimed to assess the influence of evaluative feedback on the pupil dilation response using a speech reception threshold (SRT) task. Besides the pupil dilation response, we acquired subjective ratings and two physiological biomarkers sensitive to stress: cortisol and alpha-amylase levels as determined in saliva samples. We included 34 participants with normal hearing (mean age = 52 years, age range 25–67 years) and 29 age-matched participants with mild-to-moderate hearing loss (mean age = 52 years, age range 23–64 years). Half of the participants performed a standard SRT test without feedback, and the other half performed an SRT test in which they did receive feedback and were urged to perform better. The SRT conditions targeted 50% and 71% correct reception of the sentences. Pupil size was recorded and saliva samples were obtained and participants rated their experience of the task. Participants with hearing loss performed more poorly on the SRT test than participants with normal hearing participants receiving feedback had better SRTs in the 71% intelligibility condition and higher peak pupil dilation in both intelligibility conditions than participants who did not receive feedback, irrespective of hearing status. Saliva cortisol level and alpha-amylase activity reflected the usual diurnal patterns but showed no effects of hearing status or feedback. Finally, participants who received feedback experienced more difficulties than those who did not receive feedback, irrespective of hearing status. This study underlines the importance of taking into account the influence of task instructions and feedback in a speech perception task as these factors may influence the experienced difficulties, listening effort, and task performance.

H. S. Brand of the Academic Centre for Dentistry Amsterdam, and movie buff, continues his series of columns on films featuring dentists with Rudolph The Red-nosed Reindeer, directed by Larry Roemer.

The aim of this study is to assess dental students’ opinions of the dentists’ role in primary prevention of human papillomavirus (HPV)-related oral cancer using a cross-sectional web-based survey. A questionnaire, containing questions about knowledge of HPV and oral cancer, confidence in head and neck examination and role of the dentist in preventing HPV-related oral cancer, was sent to all students of the Academic Centre of Dentistry Amsterdam (n = 912). One hundred and twenty-six (n = 126) students completed the questionnaire. Significantly, more master students (75%) than bachelor students (54.3%) were aware that HPV is a causative factor for oral cancer. Master students had more knowledge of HPV than bachelor students, but knowledge about HPV vaccination was irrespective of the study phase. The majority of dental students agreed that it is important to discuss HPV vaccination with patients. Eighty-nine percent of the students think that more education about symptoms of oral cancer will increase screening for oral cancer. Development of a protocol for screening in dental practices was considered even more important. According to dental students, dentists should discuss HPV as a risk factor for oral cancer with patients. Future dentists are willing to be involved in both primary and secondary prevention of HPV-related oral cancer. Therefore, screening for oral cancer and education about HPV vaccination should be integral elements of the dental curriculum.

Van onderzoekers mag worden verwacht dat zij hun experimenten zorgvuldig ontwerpen, uitvoeren volgens de ­ge­l­­dende wet- en regelgeving en vervolgens in hun verslag een eerlijke beschrijving geven van de gevonden resultaten. Manuscripten worden, voordat zij in een wetenschappelijk tijdschrift worden gepubliceerd, gecontroleerd door een redacteur en enkele referenten. Dit zogenaamde peer-review-systeem werkt al enkele decennia heel behoorlijk, maar toch glippen er soms artikelen door waarvan na publicatie blijkt dat er iets aan de hand is. Er verschijnt dan enige tijd later in het betreffende tijdschrift een kleine mededeling dat het eerder gepubliceerde artikel is teruggetrokken en dat het betreffende artikel offline is gezet. Soms wordt vermeld waarom het artikel is ingetrokken, maar vaak blijft de reden duister.

Speeksel is een veelzijdige vloeistof die rijk is aan molecule en micro-organismen. Zo bevat speeksel antimicrobiële eiwitten die schadelijke micro-organismen in toom houden, buffers die de etsende werking van zuren op tandglazuur beperken en glycoproteïnen - mucinen - die bijdragen aan de viscositeit van speeksel en de smering van de mondholte. Kortom, speeksel spelt een cruciale rol in de handhaving van een gezonde mond. Doordat speeksel gemakkelijk en veilig te verzamelen is, en rijk is aan analyten, is het een aantrekkeljke vloeistof voor diagnostiek. De bepaling van de hoeveelheid speeksel kan al helpen bij het vaststellen van monddroogte. Anderzijds kan de analyse van verschillende biomarkers helpen bij het vinden van de juiste remedies voor zowel orale als voor sommige systematische ziekten. Om diagnostiek in de praktijk mogelijk te maken, is er in groeiende mate belangstelling voor handzame tests. In dit artikel wordt de huidige kennis van speekseldiagnostiek in zowel de mondzorgkundige praktijk als daarbuiten besproken.

Sport- en energiedranken kunnen voor, tijdens en/of na fysieke inspanning worden gedronken. Zij vullen een vocht- en suikertekort aan dat tijdens het sporten ontstaat en gaan zo vermoeidheid tegen en bevorderen het herstel van het lichaam. Sportdranken worden al jaren niet meer alleen maar door sporters gedronken. Steeds meer niet-sporters, waaronder ook veel kinderen, drinken met regelmaat sportdranken. Sportdranken bevatten relatief veel koolhydraten (suiker), zouten en citroenzuur. Deze ingrediënten kunnen bijdragen aan tandheelkundige problemen, maar ook aan het ontstaan van overgewicht, obesitas en diabetes. Een hoge intake tijdens het sporten, in combinatie met een droge mond door uitdroging, kan leiden tot een hoge mate van tanderosie.

Objective: The aim of this study was to investigate the ability of the serine protease inhibitor plasminogen activator inhibitor type 2 (PAI-2/Serpin B2) to inhibit proteases produced by a multispecies bacterial consortium in vitro.Background: Gingival and periodontal inflammation is associated with an increased flow of protein-rich gingival fluid. This nutritional change in the microenvironment favors bacteria with a proteolytic phenotype, triggering inflammation and associated tissue breakdown. PAI-2 is produced by macrophages and keratinocytes and is present in very high concentrations in gingival crevicular fluid; the highest level in the body.Design: A multispecies bacterial consortium comprising nine bacterial strains, resembling the conditions in a periodontal pocket, was grown planktonically and as a biofilm. After seven days PAI-2 was added to the consortium and the proteolytic activity was assayed with fluorogenic protease substrates; FITC-labeled casein to detect global protease activity, fluorescent H-Gly-Pro-AMC for serine protease activity and fluorescent BIKKAM-10 for Porphyromonas gingivalis-associated protease activity. Protease activity associated with biofilm cells was examined by confocal scanning laser microscopy.Results: PAI-2 inhibited proteolytic activity of the bacterial consortium, as seen by decreased fluorescence of all substrates. PAI-2 specifically inhibited P. gingivalis proteolytic activity.Conclusion: To our knowledge, this is the first time that PAI-2 has been shown to inhibit bacterial proteases. Given the high concentration of PAI-2 in the gingival region, our results indicate that PAI-2 might play a role for the integrity of the epithelial barrier.

The emergence of antibiotic-resistant bacteria is a major public health threat, and therefore novel antimicrobial targets and strategies are urgently needed. In this regard, cell-wall-associated proteases are envisaged as interesting antimicrobial targets due to their role in cell wall remodeling. Here, we describe the discovery and characteristics of a protease substrate that is processed by a bacterial cell-wall-associated protease. Stationary-phase grown Gram-positive bacteria were incubated with fluorogenic protease substrates, and their cleavage and covalent incorporation into the cell wall was analyzed. Of all of the substrates used, only one substrate, containing a valine–leucine–lysine (VLK) motif, was covalently incorporated into the bacterial cell wall. Linkage of the VLK-peptide substrate appeared unrelated to sortase A and B activity, as both wild-type and sortase A and B knock out Staphylococcus aureus strains incorporated this substrate into their cell wall with comparable efficiency. Additionally, the VLK-peptide substrate showed significantly higher incorporation in the cell wall of VanA-positive Enterococcus faecium strains than in VanB- and vancomycin-susceptible isolates. In conclusion, the VLK-peptide substrate identified in this study shows promise as a vehicle for targeting antimicrobial compounds and diagnostic contrast agents to the bacterial cell wall.

Multiplex bead-based flow cytometry is an attractive way for simultaneous, rapid and cost-effective analysis of multiple analytes in a single sample. Previously, we developed various bead-based assays using non-magnetic beads coated with Staphylococcus aureus and Streptococcus pneumoniae antigens for the detection of antibodies. Here, we compared the performance of the assay using non-magnetic beads with one based on the newly developed magnetic beads. We optimized the magnetic beads' coupling procedure and antibody detection assays for S. aureus and S. pneumoniae antigens and we measured IgG in human pooled serum against a series of S. aureus and S. pneumoniae-derived antigens in a singleplex and in a multiplex assay, respectively. For the multiplex assay, the comparison between magnetic and non-magnetic beads showed: i) in the majority of the cases (13 of the 17 tested S. pneumoniae antigens) significantly higher Median Fluorescence Intensity (ME) values, ii) lower detection limits, iii) lower coefficient of variation (CV: 12% vs. 7% for non-magnetic vs. magnetic beads), so lower inter assay variation and hence higher reproducibility. Magnetic bead coupling is cost effective, as we used 25% of the normal amount of antigen and only 50% of the beads in comparison to the non-magnetic beads. This optimized magnetic-based assay, which combines ease of use with an improved assay performance, allows detection of antibodies with a low titer that are potentially missed with the non-magnetic-based assay. (C) 2016 Elsevier B.V. All rights reserved.

A selection of commercially available products containing stannous fluoride (SnF2)/sodium fluoride (NaF), SnF2/amorphous calcium phosphate (ACP), SnF2/NaF/ACP, tin (Sn)/fluorine (F)/chitosan were compared with phytosphingosine (PHS) with respect to their anti-erosive properties in vitro. One-hundred and twenty bovine enamel specimens were immersed in the respective product slurries for 2 min, twice daily. The formulations were diluted with either remineralization solution or artificial saliva. After each treatment, an erosive challenge was performed for 10 min, twice daily, using citric acid, pH 3.4. The specimens were stored in remineralization solution or artificial saliva until the next treatment-erosion challenge. After 10 d, tissue loss was determined using profilometry. Enamel softening was determined through surface microhardness measurements. Tissue-loss values (measured in μm and expressed as mean ± SD) for PHS, SnF2/NaF, SnF2/ACP, SnF2/ACP/NaF, and Sn/F/chitosan treatment groups and for the negative-control group, were, respectively, 35.6 ± 2.8, 15.8 ± 1.8, 22.1 ± 2.0, 22.9 ± 1.8, 16.2 ± 1.2, and 51.2 ± 4.4 in the presence of remineralization solution and 31.7 ± 3.3, 15.6 ± 2.9, 16.5 ± 2.7, 16.8 ± 2.1, 13.1 ± 3.0, and 50.7 ± 2.8 in the presence of artificial saliva. There were no significant differences in surface microhardness measurements between the treatment groups. In conclusion, PHS resulted in a significant reduction of tissue loss compared with the negative control, but in comparison, the toothpastes containing Sn2+ and F− ions were significantly more effective compared with PHS.

The present investigation evaluated the ability of an experimental di-calcium phosphate (DCP) desensitising agent used alone or combined with phytosphingosine (PHS) to occlude dentine tubules and resist a citric acid (CA) or artificial saliva (AS) challenge. Three groups of human dentine specimens (DS) were treated with the following: (1) PHS alone, (2) DCP or (3) a combination of PHS and DCP. Dentine hydraulic conductance of DS was evaluated using a digital flow sensor at 6.9 kPa. The average fluid volume for each of the treated DS was used to calculate the total dentine permeability reduction (%P) prior to and following CA immersion for 1 min or AS immersion for 4 weeks. The treated DS were subjected to both scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy analysis. Statistically significant differences (%P) were identified between the groups by ANOVA and Fisher's multiple comparison test (p < 0.05), respectively. Interestingly, both PHS and DCP appeared to work synergistically. DS treated with DCP or PHS/DCP demonstrated a significant reduction (%P) prior to and following CA or AS challenge (p < 0.05). Both the SEM and FTIR analyses showed consistent brushite crystals occluding the dentine tubules. Conversely, the application of PHS alone failed to demonstrate any significant reduction of dentine permeability (p > 0.05) or show any evidence of occlusion of the dentine tubules. DCP can be used alone or combined with PHS to decrease the dentine permeability as well as to resist a CA and AS challenge. These results would, therefore, suggest that DCP may be a suitable treatment option for dentine hypersensitivity.

Salivary agglutinin (SAG), also known as gp340 or SALSA, is a glycoprotein encoded by the Deleted in Malignant Brain Tumours 1 gene and is abundantly present in human saliva. SAG aggregates bacteria and viruses, thereby promoting their clearance from the oral cavity. The mucosa lining the oral cavity contains dendritic cells (DC) and Langerhans cells (LC), which express the C-type lectin receptors (CLR) DC-SIGN and Langerin, respectively. Both DC-SIGN and Langerin recognise mannose and fucose carbohydrate structures on pathogens and self-glycoproteins to regulate immunity and homeostasis. The purpose of this study was to investigate whether SAG interacts with these CLR and whether this interferes with the binding to oral pathogens. We show that whole parotid saliva and SAG, when coated to microplates, strongly interact with DC-SIGN and Langerin, probably via mannose and fucose structures. Also, primary human DC and LC bind parotid saliva and SAG via DC-SIGN and Langerin, respectively. Furthermore, SAG binding to DC-SIGN or Langerin prevented binding to the micro-organisms Candida albicans and Escherichia coli which express mannose and fucose-containing glycan structures. Thus, binding of saliva glycoprotein SAG to DC-SIGN and Langerin may inhibit pathogen-DC/LC interactions, and could prove to be a new immunomodulatory mechanism of SAG.

Implanteerbare cardiale defibrillatoren (ICD’s) worden geïmplanteerd als het hartritme permanent gecontroleerd dient te worden. Wanneer de ICD van een patiënt ventrikeltachycardie of ventrikelfibrilleren registreert, zal de ICD automatisch een elektrische schok afgegeven. Aangezien een ICD een apparaat is dat elektrische signalen registreert en verwerkt, is deze potentieel gevoelig voor elektromagnetische interferentie (EMI) door andere elektrische apparatuur. Patiënten met een ICD bezitten dan ook een verklaring waardoor zij op vliegvelden niet onderzocht worden met de gebruikelijke detectiepoortjes. Het gebruik van MRI is bij patiënten met een ICD eveneens gecontraïndiceerd. In de tandartspraktijk wordt ook gebruik gemaakt van allerlei apparatuur die potentieel als bron kan fungeren van lichte of matige elektromagnetische velden. Dit artikel bespreekt daarom de mogelijke interferende bronnen in de tandartspraktijk.