The Impacts of Biofilms on Our Oral Health
Whilst oral health is crucial for maintaining our physical and mental well-being, many people around the world suffer with poor oral health. Oral diseases are some of the most common non-transmissible illnesses globally, estimated to affect 3.5 billion people [1]. To tackle the challenges that oral diseases pose to individuals and society, it is essential to combat biofilms that initiate and drive many oral ailments.
The human mouth is estimated to host over 700 species of bacteria [2]. These bacteria can attach to various surfaces within the oral cavity, such as our teeth and gums, and form dental biofilms (also referred to as dental plaque) [3]. Interestingly, biofilms within the oral environment have played a significant role in the development of biofilm science. Biofilms were first observed under a microscope by Antonie van Leeuwenhoek in the late 1600s with samples taken from his own dental plaque [4]. Since then, it has become apparent that they are complex, co-ordinated microbial communities.
Oral biofilms initially form from species of bacteria referred to as primary colonisers – microorganisms that are the first to adhere to surfaces within the oral cavity. These primary colonisers create nutrients, attachment sites and a low oxygen environment, which promote other microbial species to establish and consequently form complex biofilms [5].
Dental biofilms are a normal component of our oral environment [3]. Unfortunately, though these microbial communities can be disrupted and altered by environmental stressors such as a change in diet (e.g. high sugar consumption), poor oral hygiene practices and drugs like antibiotics [3]. Such stressors can promote the proliferation of microbial species within the dental biofilm which initiate and drive oral diseases [3].
Only recently have we been able to build realistic models to mimic and understand oral microbes in a habitat close to their natural one [6]. These models are underpinning ongoing research which aims to tackle oral biofilms and the diseases that they cause.
Tooth decay
Tooth decay is the most common oral disease, affecting 2 billion people worldwide [1]. It is a consequence of microorganisms producing acids which can breakdown the enamel and dentine of our teeth. When we consume products that contain sugar, bacteria convert such sugar into acid. They can also incorporate the sugars into the ‘glue-like’ matrix which holds the biofilm together and helps it attach and adhere to the teeth [3]. If tooth decay persists due to recurrent consumption of foods with a high sugar content, or poor oral hygiene habits, cavities can start to form. Both decay and cavities can result in pain, infections and in some situations the loss of the affected tooth.
Pulpitis
Pulpitis is the inflammation of the nerves and blood vessels within the part of the tooth referred to as the pulp [7]. It can arise from dental trauma, but also from infections stemming from tooth decay. Bacteria residing in a cavity can gain access to the pulp of the tooth and trigger inflammation. If such inflammation is not treated it can lead to the development of irreversible pulpitis, where the inflamed pulp tissue can no longer heal and eventually dies [7]. This can result in the formation of an abscess, which may facilitate the spread of the infection to other parts of the mouth such as the jawbone [8].
Periodontal disease
Periodontal disease (also referred to as gum disease) is a collection of conditions which cause the infection and inflammation of the gums that surround our teeth. Gingivitis is one type of periodontal disease which is a result of biofilm build up along the gumline. The biofilm irritates the tissue and causes the gums to become red and inflamed [9]. If the biofilm is left undisturbed gingivitis can develop into periodontitis – a serious condition which was estimated to affect over 1 billion people in 2019 [1]. Periodontitis is the formation of pockets and loss of adhesion between the gums and teeth. Bacteria within the dental biofilm can produce toxins which breakdown and destroy the connections that hold our teeth in place [3], potentially resulting in tooth loss.
Infective endocarditis
Bacteria found in our mouths do not only cause oral diseases. Infective endocarditis is a condition caused by bacteria in the bloodstream forming biofilms on the lining of the heart [10]. These biofilms can initiate inflammation and cause serious damage to the heart’s valves [10]. It has been discovered that bacteria responsible for infections like gum disease can migrate from the mouth into the bloodstream [10] and cause infective endocarditis [3, 11].
To maintain good oral health and reduce our likelihood of developing an oral disease, we can each take a few small steps. It is important to regularly brush our teeth to prevent biofilm build up and consume healthy foods and drinks which do not have a high sugar content [12].
More widely, there have been calls for policy makers to include dental care in universal healthcare plans [13]. Many oral diseases stem from social and economic inequalities [1]. It is important that everyone worldwide should have access to dental care.
Make sure to check out our ‘Why should I brush my teeth?’ activity which aims to introduce biofilms in the context of oral hygiene.
References
[1] World Health Organization. Global oral health status report: towards universal health coverage for oral health by 2030. Geneva, Switzerland. WHO. 2022. Available at: https://www.who.int/publications/i/item/9789240061484
[2] Nimish Deo, P. Deshmukh, R. Oral microbiome: Unveiling the fundamentals. Journal of Oral and Maxillofacial Pathology. 2019. 23(1): 122-128. DOI: 10.4103/jomfp.JOMFP_304_18
[3] Larsen, T. Fiehn, N-R. Dental biofilm infections – an update. APMIS. 2017. 125(4): 376-384. https://doi.org/10.1111/apm.12688
[4] Høiby, N. A personal history of research on microbial biofilms and biofilm infections. Pathogens and Disease. 2014. 70(3): 205-211. https://doi.org/10.1111/2049-632X.12165
[5] Bloch, S. Hager-Mair, FF. Andrukhov, O. Schäffer, C. Oral streptococci: modulators of health and disease. Frontiers in Cellular and Infection Microbiology. 2024. 14. DOI: 10.3389/fcimb.2024.1357631
[6] Ramachandra, SS. Wright, P. Han, P. Abdal-hay, A. Lee, RSB. Ivanovski, S. Evaluating models and assessment techniques for understanding oral biofilm complexity. MicrobiologyOpen. 2023. 12(4). https://doi.org/10.1002/mbo3.1377
[7] Colgate. Reversible and Irreversible Pulpitis: Causes and Treatment. Available at: https://www.colgate.com/en-us/oral-health/mouth-sores-and-infections/reversible-and-irreversible-pulpitis-causes-and-treatment# [Accessed 2024, December 19].
[8] Colgate. Tooth Abscess & Gum Abscess. Available at: https://www.colgate.com/en-us/oral-health/dental-emergencies-and-sports-safety/abscess [Accessed 2024, December 20].
[9] OralB. Gingivitis – Symptoms, Causes and Treatment. Available at: https://www.oralb.co.uk/en-gb/oral-health/conditions/gums/gingivitis-symptoms-causes-treatments?gad_source=1&gclid=CjwKCAiAyJS7BhBiEiwAyS9uNWpp4ExbdMNe8-PdLVExMZbKsjbey2nyrPavTBS6iqOQOkJBbUKlZBoCK4sQAvD_BwE [Accessed 2024, December 20].
[10] NHS. Causes – Endocarditis. Available at: https://www.nhs.uk/conditions/endocarditis/causes/ [Accessed 2024, December 20].
[11] Vogkou, CT. Vlachogiannis, NI. Palaiodimos, L. Kousoulis, AA. The causative agents in infective endocarditis: a systematic review comprising 33,214 cases. European Journal of Clinical Microbiology & Infectious Diseases. 2016. 35: 1227-1245. https://doi.org/10.1007/s10096-016-2660-6
[12] NHS. Take care of your teeth and gums. Available at: https://www.nhs.uk/live-well/healthy-teeth-and-gums/take-care-of-your-teeth-and-gums/ [Accessed 2024, December 20].
[13] Bernabe, E. Marcenes, W. Hernandez, CR. Bailey, J. Abreu, LG. Alipour, V et al. Global, Regional, and National Levels and Trends in Burden of Oral Conditions from 1990-2017: A systematic analysis for the global burden of disease 2017 study. Journal of Dental Research. 2020. 99(4): 355-471. https://doi.org/10.1177/0022034520908533