The oral cavity contains a complex and dynamic microbial ecosystem that plays a central role in maintaining both local and systemic homeostasis. Emerging evidence indicates that disturbances in oral microbial communities-including genetic and functional diversity within species-are associated not only with oral diseases but may also contribute to the development and progression of systemic diseases. This narrative review summarises the current state of knowledge on bidirectional interactions between oral microbial communities and major organ systems. A comprehensive search of PubMed/MEDLINE, Web of Science, Scopus, and Cochrane databases was conducted for studies published between 2019 and 2025, prioritising systematic reviews, meta-analyses, and high-quality mechanistic studies. Ultimately, 40 articles were included in the narrative synthesis. The results provide clear evidence of an association between oral dysbiosis and cardiovascular disease (CVD), type 2 diabetes mellitus (T2DM), chronic respiratory infections, and adverse pregnancy outcomes (APOs). Recent data also suggest links with neurodegenerative disorders, chronic kidney disease (CKD), autoimmune diseases, and cancer. Proposed mechanisms include transient or persistent bacteraemia, systemic inflammation caused by microbial metabolites and endotoxins, disruption of immune homeostasis, molecular mimicry, and modulation of host metabolic pathways. Despite growing evidence linking oral microbial communities to systemic health, most findings are based on observational studies, and causal relationships remain to be established through longitudinal and interventional research. Understanding the connection between the mouth and the body highlights the potential for targeting oral microbial activity, virulence factors, and host inflammatory responses in disease prevention and treatment.

Secukinumab (SEC) is a recombinant, fully human monoclonal antibody that is selective for interleukin-17A (IL-17A). SEC may increase the risk of developing infections such as oral herpes and oral candidiasis. The aim of this case report and literature review was to describe chronic hyperplastic candidiasis (CHC) in a patient with psoriasis (PsO) and psoriatic arthritis (PsA) treated with SEC. CHC is a rare and atypical clinical entity. A definitive diagnosis requires biopsy of the oral mucosa for histopathological diagnosis (PHD). The differential diagnosis includes hairy tongue, hairy leukoplakia, oral lichen planus (OLP), oral lichenoid reaction (OLR), leukoplakia, frictional keratosis, morsication, oral psoriasis, syphilis, and oral lesions associated with coronavirus disease (COVID-19). In addition to the usual factors (xerostomia, smoking, antibiotics, vitamin deficiency, immunosuppression, comorbidities), the new biological therapies/immunotherapies are a predisposing factor for oral candidiasis. The therapeutic approach must be multidisciplinary and in consultation with a clinical immunologist. Dentists and specialists (oral medicine, dermatologists, rheumatologists) must be familiar with the oral adverse events of the new biological therapies. Simultaneous monitoring of patients by clinical immunology and oral medicine specialists is crucial for timely diagnosis and therapeutic intervention to avoid possible adverse events and improve quality of life (QoL).

Aim: to investigate the criteria to define implant–prosthodontic therapy failure for dentists in Croatia. Methods: We conducted a cross-sectional study using an online questionnaire among dentists in Croatia. The questionnaire consisted of demographic information and sections about experience and criteria for defining outcomes in implant–prosthodontic therapy to assess dentists’ perspectives towards implant failures, failure of prosthodontic supra-structures, potential complications and follow-up time. Descriptive statistics were used and differences were assessed using Chi-squared statistics. Results: Overall, 198 dentists completed the questionnaire, most of whom were general practitioners (81.8%), and mostly females (68.2%). 63.1% reported having worked with implants in their everyday practice. Most dentists (71.2%) have encountered implant failure, and more than half (57.1%) experienced a failed prosthodontic supra-structure. However, their definitions of implant failure or success differed significantly. Criteria for failure from 1986 were considered among 47% dentists, while 53% considered the implant to be successful if it remained in situ over a follow-up period. The three postoperative complications which patients should be warned about included pain, swelling and periimplantitis. Follow-up at six months and at five years were both chosen as appropriate by approximately the same number of dentists. Conclusions: Criteria to define implant failure differed between general practitioners and specialists, while definitions of implant success correlated with experience. The variability observed underscores the need for standardized education and unified assessment criteria to improve clinical consistency and communication.