From prostheses to implants: the microbiological secrets of an unsuspected reservoir

The integration of prosthetic devices, whether removable, fixed, or implant-supported, permanently alters the oral ecology by providing new colonization surfaces for the biofilm. For the practitioner, the challenge goes beyond simple dental plaque management: do these devices act as genuine reservoirs for opportunistic or systemic pathogens? This scoping review, structured according to the Joanna Briggs Institute methodology and PRISMA-ScR guidelines, set out to precisely map the microbial communities colonizing these critical interfaces.

The central objective was to identify microorganisms isolated directly from prosthetic surfaces and implant components — such as abutments, healing screws, or internal connections — in order to evaluate their clinical implications. To ensure the robustness of this synthesis, the authors initially identified 1,149 scientific publications across four major databases (PubMed, Web of Science, Scopus, and Embase), finally including 50 studies meeting the eligibility criteria. The tested hypothesis is based on the fact that these structures, particularly confined spaces and removable prostheses, constitute favorable ecological niches for complex flora including major periodontopathogens (P. gingivalis, T. forsythia) as well as agents involved in respiratory or systemic infections.

Review methodology

The authors conducted a scoping review following the Joanna Briggs Institute (JBI) recommendations and the PRISMA-ScR protocol. An exhaustive search was performed on October 17, 2025, in the PubMed, Web of Science, Scopus, and Embase databases.

The selection process followed a precise analytical rigor:

• Identification: 1,149 articles initially identified.
• Assessment: 81 reports were read in full after removing duplicates (557) and screening by title/abstract (592).
• Inclusion: 50 studies were selected for the final synthesis, meeting the criterion of presenting primary microbiological data collected directly from surfaces.

The analysis covered a wide diversity of clinical devices and components:

• Removable and fixed prostheses, crowns.
• Implant abutments and healing screws.
• Internal implant connections and access channels.
• Attachments, cements and explanted implants.

Researchers extracted specific data on population characteristics, collection methods, microbial identification techniques, and isolated microorganisms to characterize these microbial reservoirs.

Mapping of prosthetic microbial niches

This scoping review synthesized data from 50 studies selected from 1,149 initial records. Microbiological analyses reveal that prosthetic surfaces and implant components constitute complex reservoirs for a wide diversity of micro-organisms, including opportunistic pathogens, periodontopathogens, and systemic infectious agents.

The authors highlight that removable prostheses and the internal spaces of implant components (connections, access channels) emerge as particularly critical niches for bacterial colonization.

Component category	Identified micro-organisms
Removable & fixed prostheses	Streptococcus spp., Staphylococcus aureus, Klebsiella pneumoniae, Escherichia coli, Pseudomonas aeruginosa, Mycobacterium tuberculosis.
Implant components (Abutments, healing screws, internal connections)	Porphyromonas gingivalis, Prevotella intermedia, Tannerella forsythia, Treponema denticola, Fusobacterium nucleatum, Enterococcus faecalis, Actinomyces spp.
Specific surfaces	Luting cements, attachments (LOCATOR® type), explanted implants.

Qualitative observations and methodological limitations

The analysis of the 50 included studies highlights several key points regarding peri-implant and prosthetic microbial ecology:

• Pathogen diversity: Beyond classic periodontopathogens, the presence of bacteria associated with respiratory infections (P. aeruginosa, K. pneumoniae) on removable prostheses poses a systemic health risk, particularly in fragile patients.
• Confined spaces: Internal implant connections and screw access channels constitute protected areas where biofilm can develop, shielded from conventional hygiene measures.
• Technical heterogeneity: The authors note a high variability in collection methods (swabbing, curettage, analysis of explanted components) and identification methods (culture vs PCR vs sequencing), which limits the direct comparison of bacterial loads between studies.

Although data confirm the role of prosthetic surfaces as a reservoir, the review highlights a lack of standardization in reporting results, necessitating the establishment of uniform sampling protocols for future clinical research.

Clinical analysis: beyond classic periodontopathogens

The results of this scoping review highlight that prosthetic devices and implant components are not biologically inert. The microbial diversity identified goes far beyond the scope of the usual oral flora. The recurring presence of opportunistic pathogens such as Staphylococcus aureus, Klebsiella pneumoniae and Pseudomonas aeruginosa transforms these devices into actual reservoirs for systemic infections, particularly respiratory ones. For the practitioner, this means that prosthetic maintenance is not only a matter of material durability, but a general health issue, especially in fragile patients.

Critical ecological niches underestimated

The analysis identifies two high-risk areas: removable prostheses and the internal spaces of implant-supported components. Internal connections, access channels, and healing abutments act as microbial sanctuaries where complex communities can proliferate, sheltered from conventional hygiene measures. The detection of Mycobacterium tuberculosis in certain reported clinical samples illustrates the potential for colonization by robust pathogens within these micro-environments.

Data limitations and heterogeneity

The authors point out a major limitation: the blatant methodological heterogeneity between the included studies. Collection techniques (swabbing, curettage, sonication) and identification methods (culture versus PCR) vary considerably, complicating the establishment of a standardized microbiological profile. This lack of consensus on sampling protocols highlights the need for future standardization to better quantify the impact of these biofilms on long-term success.

Conclusion

This synthesis demonstrates that the prosthetic surface is an active biological interface. The accumulation of complex biofilms on abutments, cements, and attachments constitutes a permanent clinical challenge, correlated not only with peri-implant health, but also with the patient's global infection risk.

The essentials of the study

This review of 50 studies confirms that prosthetic surfaces and implant components (abutments, healing screws, connections) act as complex reservoirs for microbial communities including periodontopathogens and systemic pathogens such as S. aureus, K. pneumoniae and P. aeruginosa. Internal implant spaces and removable prostheses emerge as the most critical niches for the persistence of these biofilms.

In practical terms, for the practitioner:

• Seal your assemblies: Since the internal space is a major bacterial focus, the use of chlorhexidine gels or antimicrobial sealants during abutment placement is a relevant strategy to prevent the colonization of connections.
• Do not underestimate the systemic risk: The presence of respiratory pathogens on removable prostheses requires strengthening therapeutic education, particularly in fragile patients, by prioritizing combined mechanical and chemical cleaning protocols (ultrasound and antimicrobial solutions).
• Vigilance on reused components: Be particularly rigorous regarding the processing of healing abutments; as autoclaving alone may leave traces of residual biofilm, meticulous pre-sterilisation cleaning is essential.

The integration of prosthetic devices, whether removable or fixed on implants, permanently alters the oral ecology. Beyond mechanical success, managing the microbial load on these artificial surfaces represents a major clinical challenge. This scoping review, based on the Joanna Briggs Institute recommendations and PRISMA-ScR guidelines, synthesises data from 50 selected studies to identify the nature and location of microorganisms colonising our restorations.

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