Biofilm formation on implants is a primary factor in peri-implant disease. Porphyromonas gingivalis is the main causative pathogen in periodontitis. This microorganism is also a risk factor for various systemic diseases, such as certain disorders, diabetes, and pulmonary infection. The features of microbes in a biofilm can deviate significantly from that of an equivalent organism under planktonic conditions in terms of the rate of growth and gene transcription(1). Clinically, biofilms form on skin, oral mucosa and teeth sometimes cause chronic infection of dental implants(2).
Management of biofilm-related infections brings great challenges in oral implantology because the structure and composition of the biofilm itself oﬀers protection against antimicrobial agents, and regular mechanical biofilm disruption is required to enable surface disinfection. Medications that may remove such biofilms are needed for clinical use. Dental implants have become the first choice for patients seeking dental restorations. However, implant mucositis and subsequent peri-implantitis impose a great risk for implant quality and patient comfort. Additionally, bone resorption and even implant loosening account for nearly 30% of total implant failure cases(3). Significant data have confirmed that biofilm formation on the implant neck is responsible for implant mucositis(4).
P. gingivalis has been confirmed as a critical pathogen in peri-implantitis, a periodontitis represented by inflammation of peri-implant soft and hard tissues. This condition may result in dental implant failure(5), (6), and a considerably high prevalence of peri-implantitis (20% to 56%) has been reported(7). Biofilms are complex communities of microorganisms that are adherent to each other and/or to a surface and are encapsulated within a self-produced matrix(8). These organized communities represent a major implant risk because of their invasion and evasion of host defense mechanisms and their decreased susceptibility to antimicrobials(9). Biofilm-mediated resistance is due to impaired penetration of antimicrobials, upregulation of drug resistance genes, and downregulation of metabolic activity of cells included within the biofilm(10), (11). The pathogenicity of P. gingivalis is expressed by an arsenal of virulence factors connected with tissue colonization and damage and hinders host defense mechanisms(12),(13). Nutritional interactions are described to play a role regarding the coexistence of P. gingivalis and T. denticola. P. gingivalis provides isobutyric acid, which promotes the growth of T. denticola, while T. denticola produces succinate, which enhances the growth of P. gingivalis; these interactions might explain the finding that P. gingivalis and T. denticola exhibit enhanced planktonic and biofilm growth once they are cultured together compared to monospecies growth (14), (15). Antibacterial agents that possess activity against P. gingivalis include quorum sensing inhibitors, antimicrobial peptides, and natural sources such as capsaicin from Capsicum plants (chili peppers) µg/mL(16). Selenium, an important element, is critical for health. In humans, selenium is necessary for the synthesis of 25 selenoproteins. The beneficial effects of selenium on the risk of various cancers (lung, liver, colorectal, prostate, esophageal, gastric cardia, thyroid and bladder) has been confirmed(17) , (18). SeNPs have been studied for certain medical uses and as a possible substance for orthopedic implants(19). The power of selenium compounds as antibiofilm and anti-inflammatory agents has been confirmed. Nanostructured materials improve osteoblast functions (such as adhesion(20), . proliferation, synthesis of certain bone proteins, and deposition of calcium-containing minerals) and encourage adequate osteointegration because of the maximized area and roughness(21), (22). In contrast, tailoring the surface of titanium dental implants with antibacterial agents is a critical aim for implantologists and researchers. Antimicrobial coatings inhibit the infection risks of implants, which are the foremost common explanation for reverse surgery. The antibacterial actions of NPs can be classified as (1) damaging the cell membrane, causing cell lysis; (2) disrupting protein synthesis; and (3) preventing DNA replication(23),(24, 25). Many different methods are used to assess biofilms. Biological techniques include the following: semiquantitative staining, measurements of dried biomass, protein or DNA quantification, and assessments of residual viable organisms. Each method has advantages and deficiencies, but all of them provide only indirect values of the removal efficiency and are susceptible to operator variability(26, 27) (28). Standard optical microscopy, confocal laser scanning microscopy and epifluorescence microscopy (EM) are reliable tools for biofilm analysis. Additionally, scanning electron microscopy (SEM) is a proper instrument not only for intimately viewing the substratum morphology but also for observing bacterial attachment and biofilm formation on abiotic surfaces. Indeed, SEM has been useful within the event of antibiofilm materials for biomedical applications (29) (30). Scanning electron microscopy (SEM) has been used extensively for qualitative observation of biofilms because of its high resolution and is typically applied in conjunction with biological assays on bacterial biofilms(31); advanced segmentation techniques such as semisupervised machine learning methods are also typically prescribed (32).