Infrequent Flossing vs. Dirty Mouthguard: Which Is Worse?

You probably know flossing is important. But what about that mouthguard you wear at night? Both habits affect your oral health, but the research tells us they matter in different ways and understanding the difference helps you prioritize your daily routine.

What Research Shows

Interdental Cleaning and Gum Health
(Clinical Oral Investigations, 2022)
Skipping interdental cleaning (flossing, water flossers, or interdental brushes) allows plaque to accumulate between teeth, which increases gingival inflammation over time. Randomized controlled trials show that adding interdental cleaning to toothbrushing reduces inflammation and bleeding compared to brushing alone, even when overall plaque scores don't change dramatically. This makes interdental cleaning one of the most evidence-supported habits for preventing gingivitis and periodontitis.

Dirty Mouthguards and Bacterial Buildup
(The Open Access Journal for Life & Environment Research, 2022)
A dirty mouthguard can harbor dense biofilms and significant microbial loads, similar to other oral appliances. Studies on sports and nightguards show heavy contamination with bacteria linked to oral infections, bad breath, and other complications. Because mouthguards are highly porous thermoplastics, they readily accumulate bacteria and biofilm if not cleaned and dried properly, making hygiene essential.

Protective Steps

• Floss daily or use an interdental device. Water flossers, interdental brushes, and traditional floss all show benefits for reducing inflammation and preventing gum disease. Choose the method you'll actually use consistently.
• Clean your mouthguard daily with mild soap and a soft brush. Rinse thoroughly and air-dry completely before storage. This removes biofilm and reduces bacterial growth significantly.
• Use consistent, thorough brushing. Guided brushing, where coverage feedback helps you brush longer and more systematically improves plaque removal compared to rushed brushing. Feno's AI-powered monitoring can help optimize your technique, especially when interdental cleaning isn't perfect.
• Replace mouthguards annually. Most dentists recommend yearly replacement due to wear, deformation, and changes in fit, particularly for nightguards used nightly.

Bottom Line

If you must prioritize, consistent interdental cleaning has the strongest evidence for long-term gum health and tooth retention. However, regular mouthguard cleaning is equally non-negotiable, not for long-term periodontal outcomes, but to minimize bacterial buildup, infection risk, and bad breath. The best approach: do both, consistently.