Effective oral hygiene routines displace plaque biofilm from the oral cavity, reducing the risk of infection and disease. Whilst visible plaque may be easily targeted, subgingival biofilm poses an equally unwanted threat to oral hygiene.
Almost half of all adults in the UK have a degree of periodontitis that is not reversible, and between 50-90% of the adult population has some degree of gingivitis.[i] Dental plaque biofilm has a known causative effect on this, and subgingival plaque is recognised as playing a key role by creating a hypoxic environment that allows anaerobic bacteria to thrive.[ii]
Peri-implantitis, a destructive infection of the tissue surrounding an implant restoration, has a wide-ranging prevalence. One 2022 systematic review suggests it affects 20% of patients and 11.5% of implants,[iii] but prevalence could be as large as 28-56% according to a consensus report from the 6th European Workshop on Periodontology.[iv] For implant bridges and dentures in particular, an inability to remove plaque and biofilm from below the restoration can lead to widescale adverse oral health outcomes.
Understanding how subgingival plaque operates, and the oral hygiene advice that should be provided to patients, helps to improve oral health outcomes.
Hidden threat
When patients are subject to biofilm-induced gingivitis, changes in the subgingival microbiota provoke the continued growth of pathogenic species.[v] This results in inflammation of the periodontal tissue.
At this stage, a continuous cycle of destructive microbe production begins. The subgingival biofilm population gradually changes to one dominated by gram-negative anaerobes, with the literature noting the prevalence of Capnocytophaga, Selenomonas, Veillonella, Campylobacter, Fusobacterium and Prevotella.v The inflammatory process creates products that gram-negative bacteria can use as a source of nutrients, and so these continue to thrive, perpetuating an environment that supports its continued growth.
The literature finds that subgingival dental plaque and peri-implant plaque differs, with the latter having more aerobic organisms. Dental plaque at sites of standard gingivitis also presents more diverse microbe populations, with a higher plaque index and an increased proportion of strict anaerobes.[vi] It’s thought that inflammation throughout peri-implant tissue can be triggered by a thinner and healthier biofilm, with the implant itself being a partial cause of this biological response.vi With this in mind, patients with these restorations (including single- and multi-unit implants) need to be further engaged with effective oral hygiene routines, and consistently debride subgingival plaques from implant sites.
Taking action
Given the prevalence and effects of anaerobic bacteria that thrive below the gingival margin, professionals have the responsibility to remind patients to remove this biofilm regularly. Clear instructions and advice are imperative, and patients should understand that professional support may be needed at points from the dental team.
Toothbrushes can be angled to improve access to subgingival spaces, helping to remove some of the biofilm from here. This may be difficult in the posterior dentition, however, especially for those with limited dexterity. The use of traditional dental floss to access subgingival spaces is also heavily reliant on a patient’s technique, and improper approaches may leave biofilm untouched.
For patients with implant bridges and dentures, it’s vital that patients achieve effective access between every point of contact with the periodontal tissue. Toothbrushing is imperative, and traditional string floss can be helpful, however additional solutions may be recommended to ensure maximum removal of plaque.
New additions to effective routines
Interdental brushes and floss aid subgingival plaque removal, with the ability to reach deeper below the gingival margin[vii] and into spaces around dental implant restorations. The efficacy of each is difficult to ascertain, with some in the literature declaring an advantage to interdental brushes,[viii] whereas others find little difference.vii
The use of an oral irrigator, especially with a specially-designed tip to access the spaces around restorations, may be more consistently beneficial for many patients. Whilst the literature notes that oral irrigators may help to facilitate subgingival biofilm removal up to 6mm, with pulsations also reducing inflammation,vii patients need to be directed towards clinically-proven alternatives.
This includes the Ultra Professional water flosser from Waterpik™, the #1 water flosser brand recommended by dental professionals.[ix] The oral hygiene adjunct reaches below the gingival margin where brushing and traditional flossing cannot access, and is able to remove up to 99.9% of plaque from treated areas.[x] Patients can receive extra support with the Waterpik™ Implant Denture Tip, which is specifically engineered to clean around fixed implant bridges and dentures. Compatible exclusively with the Ultra Professional water flosser, the Implant Denture Tip uses a unique curved design for improved access to treatment sites, enabling patients to confidently look after their restorations.
Subgingival plaque presents a risk to oral health and restoration success, so patients and the dental team need to work together to effectively remove biofilm. Doing so will remove anaerobic bacteria from around the gingival margin, and breathe new life into a smile.
For more information on WaterpikTM water flosser products visit www.waterpik.co.uk. WaterpikTM products are available from Amazon, Costco UK, Argos, Boots and Tesco online and in stores across the UK and Ireland.
Charleane McInally is a professional educator for Waterpik, and dental hygienist
[i] National Institute for Health and Care Excellence, (2023). Gingivitis and periodontitis: How common is it? (Online) Available at: https://cks.nice.org.uk/topics/gingivitis-periodontitis/background-information/prevalence/ [Accessed February 2026]
[ii] Xu, T., Wei, Z., Zeng, Q., Feng, Q., & Zhi, M. (2026). Unveiling potential driver taxa in subgingival plaque and their roles in mediating periodontitis progression. Journal of Oral Microbiology, 18(1), 2609452.
[iii] Diaz, P., Gonzalo, E., Villagra, L. J. G., Miegimolle, B., & Suarez, M. J. (2022). What is the prevalence of peri-implantitis? A systematic review and meta-analysis. BMC Oral Health, 22(1), 449.
[iv] Association of Dental Implantology, (N.D.) Peri Implantitis – Prevalence and Risk Factors. (Online) Available at: https://www.adi.org.uk/resources/peri_implantitis_-_prevalence_and_risk_factors/ [Accessed February 2025]
[v] Iniesta, M., Vasconcelos, V., Sanz, M., & Herrera, D. (2024). Supra-and subgingival microbiome in gingivitis and impact of biofilm control: a comprehensive review. Antibiotics, 13(6), 571.
[vi] Philip, J., Buijs, M. J., Pappalardo, V. Y., Crielaard, W., Brandt, B. W., & Zaura, E. (2022). The microbiome of dental and peri‐implant subgingival plaque during peri‐implant mucositis therapy: A randomized clinical trial. Journal of Clinical Periodontology, 49(1), 28-38.
[vii] Ng, E., & Lim, L. P. (2019). An overview of different interdental cleaning aids and their effectiveness. Dentistry journal, 7(2), 56.
[viii] Imai, P. H., Yu, X., & MacDonald, D. (2012). Comparison of interdental brush to dental floss for reduction of clinical parameters of periodontal disease: A systematic review. Canadian journal of dental hygiene, 46(1).
[ix] Based on 2025 independent survey of Dental Professionals; among those who recommended branded water flossers
[x] Gorur, A., Lyle, D. M., Schaudinn, C., & Costerton, J. W. (2009). Biofilm removal with a dental water jet. Compendium of continuing education in dentistry (Jamesburg, NJ: 1995), 30, 1-6.
