Background: Elucidating host‒microbe interactions is essential for understanding oral health and disease. In periodontitis, the host inflammatory response to accumulated plaque shifts eubiotic biofilm communities toward dysbiosis, with enrichment of proteolytic bacterial species. The first line of host defence in the subgingival niche involves oral keratinocytes, which communicate with immune cells in the mucosa. Host responses to individual bacterial species have been widely characterized, but in this study, we used a co-culture model to better understand how changes in the multispecies biofilm phenotype affect keratinocyte effector function as well as the effects on inflammatory cells.

Methods: Biofilms representative of eubiotic (HA) or dysbiotic (DA) bacterial communities were developed on nitro-cellulose membranes over 7 days and then co-cultured with oral keratinocytes for 6 h. Biofilm proteolytic activity was measured with a fluorescent substrate. Multiplex cytokine analysis of the co-culture medium was used to study keratinocyte responses and the activation of inflammatory cells was investigated via flow cytometry.

Results: Proteolytic activity was greater in the DA biofilms than in the HA biofilms, most likely due to gingipains from Porphyromonas gingivalis. Keratinocytes released a range of cytokines, chemokines and growth factors, and the response to DA was more pro-inflammatory than that to HA biofilms, with relatively high levels of factors such as MIP-3a, IL-8, GM-CSF and IL-17 C. Co-culture medium from both the HA and DA biofilms elicited strong monocyte and neutrophil activation responses, although the effect of the DA biofilms was greater for monocytes than for neutrophils.

Conclusions: In this study, we show that keratinocytes have distinct response profiles to HA as compared to DA periodontal biofilm communities. The combination of products from the biofilm and the activated keratinocytes generated significant activation of inflammatory cells. This in vitro model thus provides insight on the complex host-microbiome interactions during development of periodontal disease.

Oral health professional curricula require continuous evolution to meet the needs of the population. The development of existing curricula to incorporate new topics is rarely considered in the dental education literature, and practical guidance will support educators in achieving changes locally. This paper aimed to present an evidence-based curriculum development model grounded in current dental and oral health professional education practices. To illustrate and validate this model, the integration of environmental sustainability (ES) into the curriculum will be used as a case study, offering practical insights into a real-world curriculum development process.

The paper reports the design of multivalent bacterial receptors based on reversible self-assembled monolayers (rSAMs) on gold and glass substrates, mimicking the ligand display on host cells and extracellular matrices. The layers consist of α-(4-amidinophenoxy)alkanes decorated at the ω-position with β-galactose (Gal) or sialic acid (SA). The former acts as a mobile ligand binding to the complementary adhesin, LecA, a key virulence factor of the multi-drug-resistant bacterium Pseudomonas aeruginosa (PA). Binary amphiphile mixtures containing either of these ligands, spontaneously self-assemble on carboxylic acid terminated SAMs on gold or glass surfaces to form rSAMs that are easily tunable with respect to the ligand ratio. It is shown that this results in the ability to construct multi-reusable surfaces featuring strong affinity for the bacterial adhesin and recognitive surfaces for bacteria, the latter demonstrated by incubating a culture of PA or the oral commensal species Streptococcus gordonii (SG) on either Gal or SA functionalized rSAMs. In contrast to the mobile ligand display, surfaces featuring covalently attached "static" ligands exhibited low LecA affinity. This approach to wet chemical surface functionalization is unique in imparting both rapid restorability and adaptability, the latter compatible with heteromultivalent receptor designs for boosting lectin and bacteria affinity and specificity.

OBJECTIVE: To investigate whether low daily doses of fluoridated milk, as an adjunct to oral hygiene routines with fluoridated toothpaste, can prevent caries development in enamel and dentine in adolescents.

MATERIAL AND METHODS: Adolescents (mean age 13 years) at three dental clinics in Sweden were enrolled to a randomised clinical trial (RCT) including baseline and 2-year follow-up examinations. The intervention group consumed milk supplemented with fluoride (0.75-1.0 mg) daily, while the control group consumed milk with water. Caries lesion development was assessed visually in line with the international caries detection and assessment system (ICDAS), except for proximal surfaces of premolars and molars which were assessed using a radiological classification system. Outcome measures were decayed, missing and filled surfaces (DMFS) increment, caries lesion arrest and progression.

RESULTS: Eighty seven participants in the intervention group and 72 in the control group completed the study. The intervention reduced the incidence of DMFS increment for enamel lesions, but not for dentine lesions. The degree of caries lesion arrest in outer enamel was higher in the intervention group compared to the control group, whereas caries lesion progression was lower in the intervention group.

CONCLUSION: Fluoride exerts an effect on caries lesions in the outer enamel, and fluoridated milk thus can be beneficial to adolescents with such lesions.

TRIAL REGISTRATION: Clinicaltrials.gov registration number NCT06684405.

Orale biofilm bliver patogene på grund af økologiske ændringer, som skyldes værtens kostvaner, mundhygiejne og immunrespons. Sådanne ændringer fører til dysbiose, hvor patogene bakterier dominerer og ødelægger det normale gensidige samspil mellem vært og mikrobiom. Cariogene biofilm fremmer vækst af syretolerante bakterier som mutansstreptokokker og laktobaciller. En forøget mængde supragingival biofilm nær tandkødsranden fører til gingivitis, men værtens immunrespons spiller en afgørende rolle i inflammationsforløbet. Den dysbiotiske tilstand kan progrediere til parodontitis, hvor parodontale pocher er hjemsted for komplekse mikrobielle miljøer. Antallet af anaerobe, proteolytiske bakterier stiger under indflydelse af inflammationen og tilførslen af næringssubstrater fra gingivalvæsken.

The present review summarizes the contemporary knowledge on the healthy oral microbiome and on oral biofilms in caries, gingivitis, and periodontitis. In addition, the influence of the human host on the development of oral disease is highlighted.

Oral health is maintained through a symbiotic relationship between the oral microbiome and the human host. Perturbations in the oral ecosystem, however, such as the frequent intake of dietary sugars or insufficient oral hygiene, may change the ecological conditions, induce local compositional changes of the oral microbiota and lead to diseases like dental caries, gingivitis, and periodontitis.

Recent findings suggest that an individual’s disposition to the development of gingivitis and/or periodontitis is not a sole consequence of the mere amount of biofilm, nor of the abundance of specific putative pathogens. Rather, different clinically observed trajectories to gingivitis and periodontitis are influenced by the inflammatory response of the host to dental biofilm and associated virulence factors. Dental caries is caused by a gradual shift of the oral microbiota towards acid-producing and acid-tolerance species. Importantly, the extracellular polymeric matrix of dental biofilms contributes to the preservation of low pH and is thus an essential determinant of virulence in cariogenic biofilms.

INTRODUCTION: Salivary mucin MUC5B has been suggested to support eubiosis in early oral biofilms by regulating the attachment of commensals, while downregulating dysbiotic activities related to dental caries development, such as microbial carbohydrate transport and metabolism.

METHODS: To investigate how the metabolism of glucose, a potential driver for dental caries, in early mono- and dual-species biofilms of oral Actinomyces naeslundii and Streptococcus gordonii clinical isolates was affected by the presence of the complex salivary mucin MUC5B, this study employed nuclear magnetic resonance (NMR)-based metabolomics with the interpretation of network integration.

RESULTS AND DISCUSSION: MUC5B reduced early attachment in the presence of glucose compared with uncoated surfaces but maintained even species distribution. This suggests that MUC5B may represent an innate mechanism to regulate biofilm eubiosis by supporting early coadhesion while regulating total biomass. All annotated metabolites were intermediates in either carbohydrate metabolism, pyruvate conversion, or amino acid metabolism, which was not unexpected in biofilm glucose metabolomes from two saccharolytic species since pyruvate conversion represents a junction point between glycolysis and amino acid metabolic chains. The 10 metabolites present in all early biofilms represent a core metabolome shared by A. naeslundii and S. gordonii. Such core metabolomes can be used to detect deviations in future studies. Significant differences in metabolite abundance elicited by the presence of MUC5B were also detected. In early biofilms where they were each present, pyruvate, ethanol, and metabolite 134 were present in significantly higher abundance in the presence of 25% MUC5B with 20 mM glucose (MUC5B + G) compared with a physiologic buffer with 20 mM glucose (PBS + G), while metabolites 84, 97, and sarcosine were present at significantly lower abundance. Metabolite 72 was unique to biofilms grown in MUC5B + G, and eight unannotated metabolites were unique to biofilms grown in PBS + G. A pathway enrichment analysis of the metabolites that were differently expressed in early A. naeslundii, S. gordonii, and dual-species biofilms grown with 20 mM glucose with or without MUC5B showed that pyruvate metabolism was significantly over-represented. Studying the metabolic interactions between commensal members of oral biofilms and modulatory effects of host factors such as glycoproteins in saliva during the metabolism of substrates that are potential drivers of dysbiosis, such as glucose, is essential to understand the roles of oral microbial ecosystems in oral health and disease.

The student voice plays a crucial role in shaping the curriculum and learning outcomes by providing unique insights into teaching and learning experiences. This paper has been written collaboratively with the Association for Dental Education in Europe (ADEE) Curriculum Taskforce and the European Dental Students Association (EDSA) following a number of years of collaborative working. The paper discusses the increasing focus on, and importance of, involving Oral Health Professional (OHP) students as partners—and ways of recognising and jointly acting on student feedback and ideas. The paper describes various collaborative projects between ADEE and EDSA and makes recommendations for areas that would merit further exploration with students and educators alike.

In 2025 the Association for Dental Education in Europe (ADEE) Graduating European Dentist (GED) taskforce held an international multi-stakeholder event that undertook a deep-dive into the perceived ideologies underpinning Oral Health Professional (OHP) education. This paper reports how the event was planned and conducted—and reports the challenges that were discussed in relation to delivering OHP education, potential solutions to each challenge, and priorities for which the ADEE GED taskforce should focus its activity. Due to the very collaborative and fruitful nature of this event, ADEE plans to hold further multi-stakeholder meetings across Europe.

In nature, bacteria usually exist as mixed-species biofilms, where they engage in a range of synergistic and antagonistic interactions that increase their resistance to environmental challenges. Biofilms are a major cause of persistent infections, and dispersal from initial foci can cause new infections at distal sites thus warranting further investigation. Studies of development and spatial interactions in mixed-species biofilms can be challenging due to difficulties in identifying the different bacterial species in situ. Here, we apply CellTrace dyes to studies of biofilm bacteria and present a novel application for multiplex labeling, allowing identification of different bacteria in mixed-species, in vitro biofilm models. Oral bacteria labeled with CellTrace dyes (far red, yellow, violet, and CFSE [green]) were used to create single- and mixed-species biofilms, which were analyzed with confocal spinning disk microscopy (CSDM). Biofilm supernatants were studied with flow cytometry (FC). Both Gram-positive and Gram-negative bacteria were well labeled and CSDM revealed biofilms with clear morphology and stable staining for up to 4 days. Analysis of CellTrace labeled cells in supernatants using FC showed differences in the biofilm dispersal between bacterial species. Multiplexing with different colored dyes allowed visualization of spatial relationships between bacteria in mixed-species biofilms and relative coverage by the different species was revealed through segmentation of the CSDM images. This novel application, thus, offers a powerful tool for studying structure and composition of mixed-species biofilms in vitro. IMPORTANCE Although most chronic infections are caused by mixed-species biofilms, much of our knowledge still comes from planktonic cultures of single bacterial species. Studies of formation and development of mixed-species biofilms are, therefore, required. This work describes a method applicable to labeling of bacteria for in vitro studies of biofilm structure and dispersal. Critically, labeled bacteria can be multiplexed for identification of different species in mixed-species biofilms using confocal spinning disk microscopy, facilitating investigation of biofilm development and spatial interactions under different environmental conditions. The study is an important step in increasing the tools available for such complex and challenging studies. IMPORTANCE Although most chronic infections are caused by mixed-species biofilms, much of our knowledge still comes from planktonic cultures of single bacterial species. Studies of formation and development of mixed-species biofilms are, therefore, required. This work describes a method applicable to labeling of bacteria for in vitro studies of biofilm structure and dispersal. Critically, labeled bacteria can be multiplexed for identification of different species in mixed-species biofilms using confocal spinning disk microscopy, facilitating investigation of biofilm development and spatial interactions under different environmental conditions. The study is an important step in increasing the tools available for such complex and challenging studies.