Attachment of peri-implant pathogens to laser melted abutments and the development of a novel antimicrobial coating.

Dental implant placement is undertaken increasingly frequently to restore the function and aesthetics of missing teeth. The abutment forms the interface between the implant and overlying crown, bridge or denture prosthesis. Despite reasonable long‐term survival of dental implants overall, inflammation of peri-implant tissues may develop in response to chronic insult from microbial biofilms formed on implant surfaces, leading to implant failure. Despite efforts in developing novel treatments, progression and recurrence of peri-implantitis is a major clinical problem. Therefore, focus on prevention rather than treatment of peri-implant conditions is crucial. This project aimed to investigate the early, direct attachment of peri-implant pathogens Fusobacterium nucleatum (FN) and Porphyromonas gingivalis (PG) to laser melted Ti6Al4V. Subsequently, a novel antimicrobial abutment coating was developed to reduce bacterial attachment. Both microbes attached readily to Ti6Al4V without the aid of early colonisers in the presence and absence of artificial saliva (AS). Interestingly, AS reduced FN attachment and encouraged the attachment of the more pathogenic PG to laser melted surface. The developed antimicrobial coating was composed of triclosan-loaded liposomes, tethered to the Ti6Al4V oxide layer by the amphiphilic molecule octadecylphosphonic acid. Liposomes were composed of phosphatidylcholine and cholesterol at a 7:1 w/w ratio and encapsulated 300 μg/mL triclosan in 3 mg/mL lipids. Triclosan demonstrated efficacy in inhibiting both FN and PG. The liposomes were successfully adsorbed to the laser melted surfaces, although this coating was not uniform. The triclosan-loaded liposomal coating showed high antimicrobial efficacy against FN and PG in the absence of AS. However, preconditioning of coated surfaces with AS reduced liposomal antimicrobial activity. This work indicates that bacterial attachment to oral metallic implants may differ from the successive process described in the literature. A novel liposomal coating demonstrated potential in preventing attachment and proliferation of clinically relevant implant pathogens which may reduce peri-implantitis risk

Compositional shifts within the denture-associated bacteriome in pneumonia – an analytical cross-sectional study

Introduction. Bacterial pneumonia is a common cause of morbidity and mortality in elderly individuals. While the incidence of edentulism is falling, approximately 19 % of the UK population wear a full or partial removable denture. Despite advances in denture biomaterials, the majority of dentures are fabricated using polymethyl-methacrylate. Growing evidence suggests that colonization of the oral cavity by putative respiratory pathogens predisposes individuals to respiratory infection, by translocation of these microorganisms along the respiratory tract.Hypothesis/Gap Statement. We hypothesized that denture surfaces provide a susceptible colonization site for putative respiratory pathogens, and thus could increase pneumonia risk in susceptible individuals.Aim. This study aimed to characterize the bacterial community composition of denture-wearers in respiratory health compared with individuals with a confirmed diagnosis of pneumonia.Methodology. This was an analytical cross-sectional study, comparing frail elderly individuals without respiratory infection (n=35) to hospitalized patients with pneumonia (n=26). The primary outcome was the relative abundance of putative respiratory pathogens identified by 16S rRNA metataxonomic sequencing, with quantitative PCR used to identified Streptococcus pneumoniae.Results. There was a statistically significant increase in the overall relative abundance of putative respiratory pathogens (P<0.0001), with a greater than 20-fold increase in the bioburden of these microorganisms. In keeping with these findings, there were significant shifts in bacterial community diversity (Chao index, P=0.0003) and richness (Inverse Simpson index P<0.0001) in the denture-associated microbiota of pneumonia patients compared with control subjects.Conclusion. Within the limitations of this study, our evidence supports the role of denture acrylic biomaterials as a potential colonization site for putative respiratory pathogens, which may lead to an increased risk of pneumonia in susceptible individuals. These findings support prior observational studies which have found denture-wearers to be at increased risk of respiratory infection. Further research is needed to confirm the sequence of colonization and translocation to examine potential causal relationships

Recent advances in nanocarrier-loaded gels: Which drug delivery technologies against which diseases?

International audienc