In dental research, dogs and mice are playing critical roles in solving the mysteries of human dental health.
Periodontitis is a silent epidemic affecting millions worldwide, leading to tooth loss and systemic health problems1 . Combating this complex disease requires testing new treatments for safety and efficacy. This is where the indispensable allies of periodontology research come into play: experimental animals.
Before periodontal treatments are applied to humans, extensive testing is required to understand the regeneration potential of complex periodontal tissues (gingiva, alveolar bone, periodontal ligament, and cementum)1 . Animal models fill this gap, allowing researchers to examine not only the effects of bacterial infection but also the body's complex immunoinflammatory response4 .
| Animal Model | Disease Etiology | Immunology & Microbiology | Biomaterials & Surgery | Advantages & Limitations |
|---|---|---|---|---|
| Mouse/Rat | Low | Good | Medium |
Advantages: Low cost, short reproduction cycle, genetic manipulation capability2 4 . Limitations: Small size, continuous tooth growth1 . |
| Dog | Good | Good | Excellent |
Advantages: Naturally develops periodontitis, suitable for large surgical defects1 4 . Limitations: Ethical concerns, high maintenance requirements1 . |
| Pig | Low | Low | Good |
Advantages: Similar tooth and jaw structure to humans4 . Limitations: Cost and maintenance difficulties1 . |
| Non-human Primates | Excellent | Excellent | Excellent |
Advantages: Phylogenetic and anatomical similarity to humans1 4 . Limitations: High cost, ethical restrictions, special care1 . |
Ideal for genetic studies and initial screening of therapies due to their small size and rapid reproduction.
Provide the closest natural disease progression and are excellent for surgical procedure testing.
Offer the highest similarity to human periodontitis but come with ethical and practical challenges.
Researchers experimentally induce human periodontitis in animals primarily through methods like ligature placement or bacterial inoculation4 . The ligature method involves placing a string, usually made of silk or nylon, around a tooth.
This ligature accelerates bacterial plaque accumulation, initiating a localized inflammation and alveolar bone loss process2 .
Even in extremely small and difficult-to-manipulate mice, scientists have developed new ways to apply this technique using innovative tools like nickel-titanium root canal files to place ligatures2 .
The ligature method remains the gold standard for inducing experimental periodontitis, reliably creating localized inflammation and bone loss that mimics the human disease progression.
In 2023, a team of Russian researchers published a new, accelerated periodontitis model addressing the limitations of existing models.
A 0.3 mm diameter wire ligature was applied in a figure-eight pattern to the lower and upper incisors.
Dental plaque from a human periodontitis patient was placed under the ligature. This aimed to introduce human periodontopathogens into the animal model.
Nicotine and ethanol solutions were injected under the gingiva to mimic tissue damage and intensify the inflammatory response.
Researchers used a complex inflammation index to quantitatively assess inflammation. The dramatic increase in values indicated a severe and rapid inflammatory response.
| Time Point | Main Group (Average Index) | Control Group (Average Index) |
|---|---|---|
| Pre-study (Day 0) | 9 | 9 |
| Day 7 | 195 | 12 |
Histological findings were even more compelling. Gingival tissues showed signs of exudative inflammation, while alveolar bone exhibited signs of irreversible structural resorption. This model successfully mimicked the main features of periodontitis - infection, inflammation, and tissue destruction - in just one week.
| Tissue | Observed Pathological Changes | Clinical Significance |
|---|---|---|
| Gingiva | Exudative inflammation, swelling, cyanotic color change | Tissue-level evidence of clinically observed redness, swelling, and bleeding. |
| Alveolar Bone | Irreversible bone resorption, structural loss | Indicates alveolar bone loss, the ultimate outcome of periodontitis. |
Function: Accelerate plaque accumulation in the gingival sulcus.
Usage Purpose: Initiation of experimental periodontitis.
Function: Create pathways for ligature placement in narrow interdental spaces in mice.
Usage Purpose: Ensuring surgical accuracy in small animals.
Function: Serve as scaffolds or create barriers to test regenerative treatments.
Usage Purpose: Supporting tissue regeneration and evaluating new implants3 .
Function: Intentional infection with periodontopathogenic bacteria.
Usage Purpose: Examining the role of specific periodontal pathogens4 .
Function: Mimic environmental risk factors like smoking and alcohol consumption.
Usage Purpose: Intensifying inflammatory response and tissue damage.
Function: Visualize tissue structures and pathological changes.
Usage Purpose: Detailed analysis of disease progression at cellular level.
Knowledge gained from animal models is crucial in shaping the future of dental care. A new paradigm known as precision periodontology is emerging8 .
This approach aims to develop personalized prevention, diagnosis, and treatment strategies for each patient based on their genetics, microbiome, and immune response.
Research in animal models enables the development of targeted therapies that address specific host response patterns or target specific bacterial species, promising better outcomes compared to standard protocols8 .
The transition from one-size-fits-all treatments to personalized approaches marks a revolutionary shift in periodontal care, made possible by detailed understanding gained through animal research.
From dogs to mice and primates, experimental animals in periodontology are silent and selfless partners. These models have enabled our understanding of the complex dance of periodontitis and led to groundbreaking advances in regenerative treatments and targeted therapies.
The next time you benefit from a gum disease treatment, spare a thought for these special partners who have spent countless hours helping to preserve your smile.