Dr. James Belcher, December 7, 2025

Understanding biofilm – Why plaque is so persistent

Have you ever thought about what's teeming on your teeth? Plaque, also known as dental biofilm, is much more than just a bit of dirt. It's a living biofilm – a kind of "city" made up of millions of bacteria. Here you'll learn why this is important for dental health and how to keep this stubborn buildup in check.

Biofilm verstehen – Warum Plaque so hartnäckig ist

What's behind it?

Biofilm —often colloquially called "plaque"—is a thin film of saliva components, food debris, and microorganisms that forms on teeth and gum surfaces . An intact biofilm with a balanced mix of beneficial and neutral microbes can be harmless or even protective . Problems arise when this balance is disrupted: then pathogenic bacteria colonize the biofilm, it thickens, and it can lead to gingivitis or further damage to the periodontal tissues (Sedghi et al., 2021) .

Why is it relevant?

If plaque is not removed for too long, it hardens and can form tartar . The rough tartar bed provides ideal surfaces for bacteria to adhere to – creating a breeding ground for chronic inflammation (Akcali et al., 2018). Such inflammation not only affects the mouth and teeth but can also have systemic effects via the gums. A stable, healthy biofilm is therefore a cornerstone of dental and gum health (Hajishengallis et al., 2025). 


Infobox
Without regular cleaning, plaque can form within a few hours . If ignored, it can turn into tartar – and tartar is one of the main causes of periodontitis.

Scientific background

In a healthy mouth, hundreds of bacterial species live in balance. In dysbiosis —that is, an imbalance— certain bacteria multiply disproportionately , colonize preferred areas, and form a dense, pathogenic biofilm . This protects the harmful germs from the immune system and prevents the toothbrush or saliva from reliably removing them (Sedghi et al., 2021). 

Traditional approaches such as broad-spectrum antiseptics or antibiotics are usually non-specific—they eliminate not only harmful but also beneficial microbes. While this may alleviate inflammation in the short term, it can disrupt the balance of the oral flora in the long term and increase the risk of recurring problems (Koromantzos et al., 2025). Modern approaches therefore focus on targeted microbiome modulation : They aim to block pathogenic mechanisms—instead of simply killing everything. This preserves the natural protective community and reduces the risk of inflammation (Taudte et al., 2025). 

Practical tips for everyday life

  • ✓ Clean your teeth and interdental spaces regularly — this will disrupt dense biofilm and prevent hardening (Worthington et al., 2019) .  
  • ✓ Use – if possible – microbiome -friendly care products that specifically target harmful bacteria modulate instead of destroying them all (Koromantzos et al., 2025).  
  • ✓ Have your teeth professionally cleaned regularly – especially in areas that are difficult to reach with a toothbrush or brush (Chapple et al., 2015). 
  • ✓ Avoid aggressive rinsing immediately after cleaning – this keeps a protective layer active and allows the microbiome to stabilize (Brookes et al., 2025). 
  • ✓ Pay attention to a healthy lifestyle : diet, abstaining from smoking and oral hygiene have a positive effect on biofilm and oral flora (Sabine Elisabeth et al., 2025). 

At a glance

ⓘ Plaque/biofilm is normal — what matters is its composition.

ⓘ A healthy balance protects against inflammation and gum disease.

ⓘ Selective microbiome care protects beneficial bacteria and specifically combats harmful ones.  

ⓘ Regular cleaning and gentle care are the key to healthy gums and a stable oral flora. 

Sources

  • Akcalı A, Lang NP. Dental Calculus: The Calcified Biofilm and Its Role in Disease Development. Periodontology 2000 . 2018.

  • Balaji VR, Niazi TM, Dhanasekaran M. An Unusual Presentation of Dental Calculus. Journal of the Indian Society of Periodontology . 2019;23(5):484–486. doi:10.4103/jisp.jisp_680_18.

  • Brookes Z, Bescos R, Witton R, et al. An Update on Mouthwashes: Advice for Dental Practitioners. British Dental Journal . 2025;239(5):312–315. doi:10.1038/s41415-025-9115-3.

  • Chapple IL, Van der Weijden F, Doerfer C, et al. Primary Prevention of Periodontitis: Managing Gingivitis. Journal of Clinical Periodontology . 2015;42(Suppl 16):S71–S76. doi:10.1111/jcpe.12366.

  • Eick S, et al. Effect of a Bacterial Glutaminyl Cyclase Inhibitor on Multi-Species Biofilms. Frontiers in Oral Health . 2025;6:1716625. doi:10.3389/froh.2025.1716625.

  • Hajishengallis G, Chavakis T. Local and Systemic Mechanisms Linking Periodontal Disease and Inflammatory Comorbidities. Nature Reviews Immunology . 2021.

  • Koromantzos PA, Bobetsis YA, Giota C, et al. Effect of Adjunctive Use of Commercial Daily Mouthwashes on Periodontal Health: An Umbrella Review. Journal of Clinical Periodontology . 2025. doi:10.1111/jcpe.70061.

  • Li J, et al. Identification of Early Microbial Colonizers in Human Dental Biofilm. Journal of Applied Microbiology . 2004;97(6):1311–1318. doi:10.1111/j.1365-2672.2004.02420.x.

  • Sabine Elisabeth G, Yuxi Z, Jiawen Y, et al. Systemic, lifestyle and environmental modifying factors in the pathogenesis of periodontitis. Journal of Periodontal Research . 2025.

  • Sedghi L, DiMassa V, Harrington A, Lynch SV, Kapila YL. The Oral Microbiome: Role of Key Organisms and Complex Networks in Oral Health and Disease. Periodontology 2000 . 2021.

  • Taudte N, et al. Novel Small Molecule Targeting PgQC Reduces Porphyromonas Gingivalis Virulence. bioRxiv . 2025.09.30.679452. doi:10.1101/2025.09.30.679452. Preprint, not peer reviewed.

  • Tartaglia GM, Kumar S, Fornari CD, Corti E, Connelly ST. Mouthwashes in the 21st Century: A Narrative Review About Active Molecules and Effectiveness on the Periodontal Outcomes. Expert Opinion on Drug Delivery . 2017;14(8):973–982. doi:10.1080/17425247.2017.1260118.

  • Trombelli L, Franceschetti G, Farina R. Effect of Professional Mechanical Plaque Removal Performed on a Long-Term, Routine Basis in the Secondary Prevention of Periodontitis: A Systematic Review. Journal of Clinical Periodontology . 2015;42(Suppl 16):S221–S236. doi:10.1111/jcpe.12339.

  • Worthington HV, MacDonald L, Poklepovic Pericic T, et al. Home Use of Interdental Cleaning Devices, in Addition to Toothbrushing, for Preventing and Controlling Periodontal Diseases and Dental Caries. The Cochrane Database of Systematic Reviews . 2019;4:CD012018. doi:10.1002/14651858.CD012018.pub2.

  • Zeng Y, Lin D, Chen A, Ning Y, Li X. Periodontal Treatment to Improve General Health and Manage Systemic Diseases. Advances in Experimental Medicine and Biology . 2025. 

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