Emerging threat: Pseudomonas aeruginosa and dental implant longevity: Part 1

The number of single dental implants being placed continues to rise across various disciplines, including general dentists, periodontists, and oral surgeons. Similarly, there is quite an uptick in the use of implant-retained overdentures. This increase is also accompanied by a concerning rise in implant failures. Failures, though accuracy of recording is questioned, are a growing worry among all demo-graphics, the elderly in particular.

Our populations are aging and for those with compromised health or residing in assisted living, memory care, or skilled nursing facilities, the risk can be great, if not deadly. Aging often brings systemic conditions that increase the risk of peri-implant diseases.^1,2 Many elderly individuals face challenges with oral hygiene and implant maintenance due to physical or cognitive limitations, lack of access to care, or limited financial resources. In assisted living settings, these challenges are further compounded by restricted access to specialized dental care and reliance on caregivers for oral hygiene. Single implants may not be as much of a problem, but what about overdentures in a patient with arthritis or Parkinson’s disease? Do they have O-rings, caps, or a clip system that need maintenance? Will they be able to visit a dental home for evaluations, radiographs, or replacement parts?

While clinicians are gaining more education on implant maintenance and care, many providers still lack the necessary knowledge and proper equipment to effectively manage their patients’ implants. Additionally, staying up-to-date with the evolving science on bacterial composition in peri-mucositis and peri-implantitis remains a challenge for many. Unsuccessful or failing implants can result from various factors, including overload, fractures, malposition, complications in guided bone regeneration, and systemic causes such as smoking, osteoporosis, bisphosphonate use, diabetes, and plaque-associated pathological disease.³

Peri-implantitis is an inflammatory condition that affects the tissues surrounding a dental implant, leading to bone loss and potentially implant failure. Whether due to poor oral hygiene, a weakened immune system, implant placement, or loose parts, it’s concerning and frustrating.

Bacterial species associated with peri-implantitis

Studies are identifying bacterial species associated with peri-implantitis that are making the game interesting. A case-control study found that peri-implant disease status was significantly associated with the submucosal presence of Porphyromonas gingivalis (Pg) and Tannerella forsythia (Tf).⁴ Sound familiar? It’s periodontal disease 101. A systematic review reported that peri-implantitis is associated with the presence of Staphylococcus epidermidis and specific periodontopathogens, including Pg, Tf, Treponema denticola (Td), and Fusobacterium nucleatum (Fn).⁵

Not-so-new research has pointed to microbes, bacteria, and viruses that may not be top of mind. Opportunistic pathogens such as Pseudomonas aeruginosa (P. aeruginosa) and Staphylococcus aureus, fungal organisms like Candida albicans, and herpes family viruses, including cytomegalovirus and Epstein-Barr virus, have significant influence.^6-10 The numerous factors contributing to disease accentuate the complexity and heterogeneity of peri-implantitis.¹¹

In the sweeping list of players, one bacteria of particular interest is P. aeruginosa, a notably aggressive pathogen capable of infecting almost any part of the body. This gram-negative facultative anaerobe is a versatile opportunistic microbe with significant implications for systemic health and dental implant failure. Renowned for its resilience in diverse environments, including human tissues and medical devices, P. aeruginosa is highly adaptable and ubiquitous. It thrives in hospitals, hot tubs, swimming pools, contact lens solutions, and on surfaces, particularly in moist environments. It can act as a resourceful pathogen, causing systemic infections such as wound and urinary tract infections, sepsis, and pneumonia.^12-15

P. aeruginosa’s role in peri-implant infections

P. aeruginosa is increasingly relevant in dentistry due to its role in peri-implantitis and biofilm-related infections. Its ability to form biofilms, resist antibiotics, and produce virulence factors contributes to implant failure and poses significant clinical challenges.^16,17 These bacteria colonize on dental implants, especially those with compromised surfaces or poor oral hygiene, and can integrate with other oral pathogens, worsening peri-implant inflammation. Once established, P. aeruginosa biofilms are highly resistant to host defenses and antimicrobial treatments. Biofilm-associated P. aeruginosa on implants requires innovative methods such as photodynamic therapy or biofilm-disrupting agents for effective treatment.^18-20

A cross-sectional study found that probing depth, clinical attachment loss, and bleeding on probing were worse near implants with gram-negative enteric bacteria or P. aeruginosa. These bacteria were linked to poorer clinical outcomes in patients with peri-implant disease.²¹

P. aeruginosa and bone loss

P. aeruginosa contributes to bone loss around dental implants through several mechanisms.²² Its lipopolysaccharide (LPS) component plays a key role. LPS is a molecule found on the outer surface of gram-negative bacteria. Lipo is the fatty part of a molecule, and saccharide is the sugar part. LPS triggers bone breakdown by both directly and indirectly stimulating the formation of bone-resorbing cells (osteoclasts). While LPS alone doesn’t directly create osteoclasts from bone marrow cells, it does so in the presence of bone-forming cells (osteoblasts) or if osteoclast precursors are first exposed to a small amount of RANKL (a key protein in bone remodeling). This indirect pathway involves inflammatory signals (TNF-, IL-1, and IL-6), which further promote osteoclast formation.²³ Studies in mice show that LPS-induced bone loss depends on the TLR4 receptor. Essentially, P. aeruginosa LPS hijacks bone remodeling processes, leading to accelerated bone resorption and implant instability.

As we continue to unravel the complexities of P. aeruginosa and its role in peri-implant infections, it becomes clear that this opportunistic pathogen is not just a bystander but an active driver of disease. Its ability to evade host defenses, resist treatment, and manipulate bone metabolism stresses the need for innovative diagnostic and therapeutic strategies.

In Part 2, we will take a deeper dive into P. aeruginosa’s arsenal of virulence factors—including adhesion mechanisms, exotoxins, and quorum-sensing systems—that further contribute to its pathogenicity. We will also investigate the challenges in detection, the growing concerns surrounding antibiotic resistance, and promising new approaches that may help tip the scales in our favor. Stay tuned for the next installment as we continue to shed light on this formidable bacterial adversary.

Editor's note: This article appeared in the June 2025 print edition of RDH magazine. Dental hygienists in North America are eligible for a complimentary print subscription. Sign up here.