ORAL MICROBIAL HOMEOSTASIS · BONE AND JOINT HEALTH
Oral microbiome, periodontal disease and systemic bone-related diseases in the era of homeostatic medicine
How a disrupted oral ecosystem may intersect with inflammation, bone remodelling and joint health—and where the evidence still stops.
Volume 73 · 443–458 · 2025
DOI: 10.1016/j.jare.2024.08.019
ORIGINAL PAPER · AT A GLANCE
Volume 73 · Pages 443–458
Oral microbiome, periodontal disease and systemic bone-related diseases in the era of homeostatic medicine
Hu · Chen · Zou · Chen · Luo · Zhong · Ma
The review maps how oral microbial homeostasis may relate to rheumatoid arthritis, osteoarthritis, osteoporosis and osteomyelitis, and examines proposed biological routes, diagnostic possibilities and emerging therapeutic strategies.
This is a PerioMed-designed bibliographic presentation and editorial synthesis, not a reproduction of the publisher’s first page or full abstract.
01 · THE QUESTION
When the oral ecosystem loses balance,
what might happen beyond the mouth?
The review shifts attention from individual bacteria to the relationship among the microbial community, the host immune response and the local environment.
Oral microbial homeostasis describes a dynamic, mutually beneficial balance. Diet, smoking, lifestyle, socioeconomic conditions, genetics, saliva, the mucosal barrier and host immunity can all influence that balance. Dysbiosis describes a shift towards a microbial and inflammatory state associated with tissue damage.
HOW THE PAPER WAS BUILT
A broad search.
A narrative synthesis.
The authors searched PubMed from database inception to 3 August 2024 without language limits. The article brings several research traditions together, but it does not report a PRISMA flow diagram, detailed eligibility criteria, formal risk-of-bias assessment or meta-analysis.
Its strength is breadth. Its limitation is certainty.THE CENTRAL IDEA
Health is not a sterile mouth.
It is a regulated ecosystem.
Commensal microorganisms can support immune regulation and local bone homeostasis. The question is what changes when host–microbe balance becomes unstable.
Microbial community and host remain in a dynamic balance
- Stable ecological relationships
- Regulated immune responses
- Oral barrier integrity
- Balanced bone remodelling
The ecosystem shifts towards persistent inflammation
- Changed microbial composition
- Immune overactivation
- Periodontal tissue damage
- Potential systemic signalling
WHAT THE REVIEW REPORTS
Four conditions.
Four different evidence pictures.
Grouping these diseases under one heading does not mean that the evidence is equally strong—or that the same mechanism explains each relationship.
Rheumatoid arthritis
Studies report altered oral microbial patterns and periodontal bacterial DNA or antibodies in some people with RA. These findings support microbial and immune hypotheses, but do not establish the direction of effect.
Osteoarthritis
The review describes bacterial DNA in joint samples and experimental effects on cartilage cells. Much of the evidence remains laboratory-based or preclinical.
Osteoporosis
Periodontitis and osteoporosis have been associated in observational research. Animal models suggest possible roles for inflammation and the oral–gut axis, while shared risk factors complicate causal interpretation.
Osteomyelitis
Oral organisms have been identified in selected infections and case reports. This can be clinically relevant in individual cases, but does not support broad claims of routine causation.
THREE PROPOSED PATHWAYS
How might signals travel
from the mouth to bone?
Distant transmission
Oral bacteria, bacterial components or extracellular vesicles may enter the circulation and reach distant tissues.
Detection outside the mouth supports biological plausibility; it does not prove that viable oral microbes initiated disease there.Oral–gut axis
Swallowed oral microorganisms and inflammatory signals may influence gut microbial balance, metabolism and immune responses.
Animal findings are informative, but human evidence remains limited.Systemic inflammation
Periodontal inflammation may add to a wider inflammatory burden through cytokines, endotoxins and immune activation.
The magnitude and clinical relevance of this effect in humans are not yet established.FROM MECHANISM TO TISSUE
The review proposes effects on cells that build, resorb and maintain bone and cartilage.
Most of this work is experimental. It helps explain how a relationship could occur, but biological plausibility is not the same as a demonstrated clinical effect in humans.
DIAGNOSIS AND TREATMENT
Promising research directions.
Not established clinical tools.
Microbial biomarkers
Candidate signatures need validation in large, independent cohorts and comparison with current diagnostic standards.
Probiotics
Early experimental findings are promising, but they do not establish treatment effects for systemic bone disease.
Mesenchymal stem-cell approaches
Potential links between microbial balance and stem-cell function are mainly preclinical.
Oral microbiota transplantation
A research concept with unresolved questions about targeting, safety and long-term effects.
WHAT THE REVIEW SUPPORTS
A biologically plausible oral–systemic research field
- Oral microbial homeostasis is influenced by microbial, host and environmental factors.
- Periodontal inflammation may interact with systemic immune and metabolic pathways.
- Experimental work identifies mechanisms worth testing in stronger human studies.
- Oral microbial patterns may eventually contribute to risk prediction or precision medicine.
WHAT IT DOES NOT ESTABLISH
Direct causation or ready-to-use treatments
- Oral dysbiosis alone has not been shown to cause RA, OA, osteoporosis or osteomyelitis.
- Bacterial DNA in a distant sample does not prove that living oral bacteria initiated disease.
- Candidate microbial signatures are not validated diagnostic tests.
- Probiotics, stem-cell strategies and oral microbiota transplantation are not established treatments for these systemic conditions.
CLINICAL MEANING TODAY
Keep oral health in the wider health conversation—without promising more than the evidence shows.
For clinicians, this means recognising shared risk factors, managing periodontal inflammation according to established guidance and coordinating care when a patient’s wider health requires it. For patients and the public, maintaining oral health remains important for its proven oral benefits and as part of general health care. This review does not show that periodontal treatment prevents or cures systemic bone disease.
PERIOMED BOTTOM LINE
“The mouth is part of the bone-health conversation. It is not a proven single cause.”
This review maps plausible links between oral microbial imbalance, inflammation and bone or joint disease. The next step is stronger longitudinal and interventional human research that can separate association, mechanism and causation.