Adults with type 2 diabetes who clean between teeth at least three times a week spend more time in the healthy glucose range.
A new clinical research study has found that adults with type 2 diabetes who clean between their teeth three or more times a week (with floss or interdental brushes) have more stable 24-hour blood glucose. Adults with 20 or more natural teeth also showed lower glucose levels throughout the day.
The innovative new research by Sunstar Group, Clinic Masae Minami, and the Minami Diabetes Clinical Research Center, published in advance in the American Diabetes Association’s Journal Diabetes Spectrum, explored the underexposed relationship between daily oral care routines and glucose management. The study also looked at the role of inflammation potentially underlying this association.
Adults with type 2 diabetes who practice interdental cleaning at least three times per week had extended periods within the healthy target glucose range and lower overall glucose variability, showing the significance of daily oral care routines such as interdental cleaning. The new study also demonstrates the potential benefits of integrating medical and dental care for adults with diabetes.
This latest study builds on previous findings of the close interconnection between diabetes and periodontal disease. Treating periodontal disease is known to potentially lower HbA1c levels, an established glycemic indicator. While previous studies focused on clinical treatment, the potential impact of oral care practices on daily glucose management in type 2 diabetes has been underexplored.
Latest CGM (Continuous Glucose Monitoring) technology simplifies tracking of daily glucose variation patterns and TIR (Time in Range, the proportion of time blood glucose levels remain within the target range of 70-180mg/DL). This is a vital indicator reflecting the ‘quality’ of glycemic variability and is closely linked to the development and progression of diabetes-related complications.
In the research study a total of 104 adults with type 2 diabetes were monitored using arm-mounted sensors for continuous glucose monitoring (CGM) for 14 days, alongside blood tests and surveys on their oral health routines. Researchers collected information on dental visits, toothbrushing, interdental cleaning, and how many natural teeth they had.
Researchers also analysed Time in Range (TIR) – the time blood glucose stays in the target range and Glucose Management Indicator (GMI), an estimate of overall glucose control based on CGM data.
Key research findings summary:
- People who cleaned between teeth ≥3 times/week had:
- Higher TIR (more time in the 70-180mg/DL range)
- Lower GMI (reflecting lower 24-hour average glucose)
- Lower fasting glucose and stable day-to-day glucose profiles
- People with ≥20 natural teeth showed more favourable 24-hour glucose profiles than those with fewer teeth.
- More frequent dental visits and twice daily toothbrushing were also linked with healthier metabolic and inflammation markers.
While these links remained significant even after accounting for age and sex, importantly, the benefits of interdental cleaning were not fully explained by inflammation markers, suggesting other pathways may be involved.
Detailed research findings:
1. Correlation between oral hygiene practices and glycemic/metabolic indicators
61% reported regular dental visits, 78% brushed at least twice daily, and 71% performed interdental cleaning weekly. The average number of natural teeth was 25.0 ± 3.6.
Higher dental visit frequencies correlated with lower HbA1c, fasting blood glucose, and BMI. Similarly, higher brushing frequencies were associated with lower BMI, high-sensitivity CRP, and urinary albumin-creatinine ratios. Frequent interdental cleaning was linked to lower fasting glucose, GMI, BMI, and three inflammation markers, as well as higher TIR, suggesting potential associations with systemic inflammation.
2. Comparison of glycemic management indicators by oral health status
Participants who followed interdental cleaning at least three times per week exhibited statistically significant associations with lower fasting glucose, HbA1c, and GMI, and higher TIR. Distinct differences in 24-hour CGM monitoring values were observed (Figure 1), and the trends remained statistically significant even after adjustments for gender and age (Figure 2).
Additionally, participants with 20 or more natural teeth demonstrated more favorable 24-hour glucose profiles compared to those with fewer teeth (15-19 teeth). Although individuals with less than 20 teeth represented approximately 10% of the group, strong associations with heightened glycemic profiles were found (Figure 1).
3. Analysis considering inflammation
Interdental cleaning habits performed three or more times per week showed significant associations with achieving clinical targets for TIR and GMI, even after adjustments for various inflammation markers. This suggests the possibility of mechanisms beyond inflammation linking these factors.
Bar graphs comparing glycemic management indicators between different groups based on oral hygiene status (blue bars vs. orange bars), adjusted for gender and age. Asterisks (*) indicate statistically significant differences between the two groups. GMI: Glucose Management Indicator (a value converted from CGM-measured glucose levels into an HbA1c equivalent). TIR: Time in Range (the percentage of time blood glucose levels remain within the target range).
Although a cross-sectional study, the research demonstrates that daily oral care routines, especially interdental cleaning and tooth retention, are associated with steadier blood glucose and play a significant role in diabetes management.
Integrating dental care and oral health checks into diabetes care could also provide a practical, low-cost step to support glucose management, while improving patients’ understanding of this two-way connection between oral hygiene and diabetes, and increasing dental visits.
Dr. Yasutaka Maeda, Diabetes Specialist at Clinic Masae Minami and Director of Minami Diabetes Clinical Research Center, comments: “This study demonstrated a strong relationship between daily oral hygiene practices and glucose management. Dietitian-led oral hygiene assessments conducted in this study prompted patients to better understand periodontal disease, leading to more dental visits.
“Nurses are also now utilizing Oral Frailty Check Sheets to address ageing-related issues in diabetes care and establishing a smooth medical-dental collaboration system within our clinic. More healthcare facilities are expected to implement similar collaborations by utilizing these research findings which clearly communicate the importance of oral care for people with diabetes.”
