Insulin resistance and dental health: Why dentists are the first line of defense

Dentists and allied dental health professionals can often be the first health-care providers to detect signs of systemic inflammation—bleeding gums, delayed healing, recurrent abscesses, or unexplained tooth mobility. By recognizing that these findings might also reflect insulin resistance, a patient’s long-term health trajectory can be changed. Insulin resistance (IR) may silently predate diabetes by 10 to 15 years, giving dental professionals a unique window of opportunity to intervene early.¹

How is insulin resistance measured?²

Insulin resistance is measured indirectly through tests like the HOMA-IR (Homeostatic Model Assessment) or by evaluating blood sugar levels and other risk factors. Numbers indicating insulin resistance include a fasting blood glucose level of 1 or higher, an A1C between 5.7% and 6.4%, or a HOMA-IR score greater than 2.

What are the risk factors for insulin resistance?

Insulin resistance can’t be identified by appearance alone. While overweight and obese individuals may be at increased risk, many normal-weight individuals also exhibit IR.

Key risk factors include³:

• Blood pressure readings of 130/80 or higher
• A fasting glucose level over 100 milligrams per deciliter (mg/dL)
• Elevated HbA1c above 5.7%
• A fasting triglyceride level over 150 mg/dL
• An HDL cholesterol level under 40 mg/dL in men and 50 mg/dL in women
• Skin tags
• Patches of dark, velvety skin under the arms or on the neck (acanthosis nigricans)
• Damage to tiny blood vessels in the backs of the eyes, which can lead to a condition called retinopathy
• Chronic gingival inflammation, rapid bone loss, and delayed healing without local etiology (bacteria)

Insulin resistance’s influence on periodontal disease and tooth loss

A study examining more than 8,000 participants found that people with the most missing teeth were 30% more likely to exhibit insulin resistance.⁴ Poor diet quality and elevated systemic inflammatory markers partly mediated this link. For example, tooth loss, often resulting from periodontal disease, reduces masticatory function, promotes soft-food diets low in fiber and antioxidants, and fuels systemic inflammation. The outcome is a self-perpetuating cycle: fewer teeth → poorer diet → higher inflammation → worsening insulin resistance.

Another study demonstrated how oral pathogens such as Porphyromonas gingivalis and Tannerella forsythia directly impair insulin signaling through endotoxin-driven inflammation, oxidative stress, adipokine imbalances, and microbial translocations leading to infection and inflammation.⁵ Together, these mechanisms explain how chronic periodontitis can act not only as a symptom but also as a driver of insulin resistance.

Further reading: Type 5 diabetes (severe insulin-deficient diabetes): What every dental professional should know

How can patients reverse insulin resistance?

Insulin resistance is reversible. Early lifestyle modifications can restore cellular insulin sensitivity and benefit both oral and systemic health:

• Exercise regularly: Physical activity is one of the strongest insulin sensitizers.
• Achieve healthy weight: Modest weight loss reduces pancreatic strain and improves glucose uptake.
• Eat for metabolic balance: Favor nonstarchy vegetables, whole grains, fruits, and lean proteins. Limit processed sugars and saturated fats. Eat polyphenols—found in green tea, berries, cocoa, grapes, and herbs—to combat both periodontal inflammation and insulin resistance. Their antioxidant and antimicrobial properties reduce gingivalis colonization, improve endothelial health, and restore insulin sensitivity.
• Sleep and stress management: Adequate sleep and stress reduction blunt cortisol spikes that worsen insulin resistance.

Why should dental care providers screen for insulin resistance?

1. Early detection saves years: Insulin resistance precedes type 2 diabetes by up to 15 years; identifying it early can prevent micro- and macrovascular damage.
2. Shared inflammatory pathways: Treating periodontal inflammation helps lower systemic cytokine load, potentially improving insulin sensitivity.
3. Patient education: Discussing metabolic risk during dental visits reinforces the concept of the mouth-body connection and motivates lifestyle change.
4. Interdisciplinary collaboration: Timely referral to primary-care physicians or endocrinologists enables early lab testing (fasting glucose, HOMA-IR, lipid panel).

Conclusion

Insulin resistance isn’t just an endocrinologist’s problem—it’s a dental concern. For the practicing dentist, recognizing signs of IR offers a unique opportunity to prevent diabetes, reduce inflammation, and preserve both teeth and systemic health. By identifying risk early, coordinating with physicians, and guiding patients toward anti-inflammatory, polyphenol-rich nutrition and healthy habits, dentists can treat beyond the tooth—protecting health, not just smiles.

Editor’s note: This article originally appeared in Perio-Implant Advisory, a chairside resource for dentists and hygienists that focuses on periodontal- and implant-related issues. Read more articles and subscribe to the newsletter.

References

1. Tabák A, Herder C, Rathmann W, Brunner EJ, Kivimäki M. Prediabetes: a high-risk state for diabetes development. Lancet. 2012;379(9833):2279-2290. doi:10.1016/S0140-6736(12)60283-9
2. Insulin resistance and prediabetes. Blood tests. National Institutes of Health. National Institute of Diabetes and Digestive and Kidney Diseases. Reviewed March 2025. https://www.niddk.nih.gov/health-information/diabetes/overview/what-is-diabetes/prediabetes-insulin-resistance
3. Booth S. Insulin resistance — what you need to know. WebMD. Reviewed April 22, 2024. https://www.webmd.com/diabetes/insulin-resistance-syndrome
4. Hao Y, Li S, Dong S, Niu L. The association between tooth loss and insulin resistance mediated by diet quality and systemic immunoinflammatory index. Nutrients. 2023;15(23):5008. doi:10.3390/nu15235008
5. Thouvenot K, Turpin T, Taïlé J, Clément K, Meilhac O, Gonthier MP. Links between insulin resistance and periodontal bacteria: insights on molecular players and therapeutic potential of polyphenols. Biomolecules. 2022;12(3):378. doi:10.3390/biom12030378