Qualitative assessment of the removable denture microbiome.

Introduction: Assessment of the denture plaque can provide a valuable report regarding the oral health of geriatric patients and the oral hygiene habits in this population group. Focusing on the current research gap on this topic in Romania, our research aims to highlight the microbial plaque on the different surfaces and types of removable poly(methyl methacrylate) (PMMA) prostheses to qualitatively evaluate the microbial species, and to assess the combined effect of mechanical and chemical cleaning of dentures on the prosthetic microbiome.

Methods: The prosthetic plaque from four denture wearers was identified with a UV activated fluorescent revealer and digitally photographed. Swab samples according to a certain hygiene protocol were cultured on three different growth media such as blood agar (BA), bromothymol blue lactose agar (AABTL) and Sabouraud dextrose agar (SDA).

Results: Denture plaque was variably distributed on the surface of the prostheses. Regardless of the denture type (conventional complete denture, tooth or implant supported overdenture, removable partial denture) the microbial plaque was identified at the retentive areas, especially at interdental spaces. The main plaque deposition areas were the vestibular incline of the labial flange of the maxillary denture and the lingual incline of the posterior lingual flange of the mandibular denture. The prosthetic microbiome consisted of pathogenic Gram-positive aerobes (Streptococcus spp. and coagulase-negative Staphylococcus spp.), Gram-positive anaerobes (Actinomyces spp. and Klebsiella spp.) as well as subspecies of fungi of the genus Candida.

Conclusions: Despite its poor variety, the denture microbiome in the investigated cases hosts colonies with high pathogenic potential. Some areas of the prostheses are more likely to accumulate dental plaque. Dentists should insist through more regular checks of the patients and their caregivers on ensuring the biocontrol of the dentures, especially in frail geriatric patients exposed to greater risks related to general health.