Plaque and prevention

This article explores the role plaque plays in periodontal disease, and considers preventive strategies that may help to reduce the risk of poor soft tissue health.

The ‘Oxford Dictionary of Dentistry’ defines plaque as: ‘A biofilm consisting of an organized bacterial community, salivary mucins and proteins adhering to tooth surfaces, restorations, and prosthetic appliances. Plaque forms by attachment of bacteria to the outer surface of the pellicle, predominantly in stagnation areas not having the benefit of the self-cleansing actions of the oral cavity.’1

According to Page and Kornman (1997), plaque is a major cause of gum disease. They wrote: ‘Experts agree that human periodontitis is initiated and perpetuated by a small group of predominantly gram-negative, anaerobic or microaerophilic bacteria that colonize the subgingival area.’2

They continued: ‘Indeed, at the 1996 World Workshop on Clinical Periodontics, the relevant working group concluded (2) that most human periodontitis is caused by Porphyromonas gingivalis, Bacteroides forsythus and Actinobacillus actinomycetemcomitans.’2

Building on the concept of plaque as one causative factor of periodontal disease, Scully (2016) reported, ‘It has been estimated that 80% of the periodontal tissue damage is due to an inappropriate host response to pathogenic bacteria.’3

In addition, earlier this year, Chapple and colleagues (2017) issued a report on group 2’s findings from the joint EFP/ORCA workshop on the boundaries between caries and periodontal diseases, writing: ‘Periodontal diseases and dental caries are complex diseases with multiple and diverse exposures that impact upon risk of disease initiation (risk factors) or progression of existing disease (prognostic factors). Exposures include those that are inherited (e.g. genetic variants), those that are acquired, such as social, educational and economic factors, and the local environment (e.g. biofilm load or composition), other diseases (e.g. sub-optimally controlled diabetes) and lifestyle (e.g. smoking, consumption of sugars, carbohydrate intake) factors. These may arise in different combinations in different individuals, and at an individual patient level may also have differentially weighted effects.’4

Preventive care

In real terms, the Adult Dental Health Survey of 2009 indicated that just 17% of dentate adults in England, Wales and Northern Ireland had very healthy periodontal tissues and no periodontal disease (i.e. no bleeding, no calculus, no periodontal pocketing of 4mm or more and, in the case of adults aged 55 or above, no loss of periodontal attachment of 4mm or more anywhere in their mouth).5

Also of significances is that the Group B consensus report of the 5th European Workshop in Periodontology stated: ‘Currently oral plaque biofilm disruption is the most effective way to treat and prevent both conditions [gingivitis and periodontitis]’.6

Given the low level of healthy periodontal tissue, as highlighted in the ADHS – and this despite 75% of respondents claiming to brush twice-daily and 25% of those saying they floss every day5 – there appears to be an unmet oral health need.

Boyle and colleagues (2014) offer clarification on this issue: ‘Dental plaque is the main cause of oral diseases and can be removed mechanically by ‘effective’ brushing and flossing. However, a very large proportion of plaque on teeth is left behind by most individuals and soft tissues largely untouched mechanical means of plaque control.’7

They added, ‘A major advantage which a mouthwash has is that antimicrobial mouthrinses can reach virtually all residual plaque.’7

In terms of offering patients practical advice for home care to help disrupt plaque biofilm in the mouth, Working Group 2 of the 11th European Workshop in Periodontology on the primary prevention of Periodontitis, reached the following consensus: ‘We support the almost universal recommendations that all people should brush their teeth twice a day for at least 2 min. with fluoridated dentifrice. Expert opinion is that for periodontitis patients 2 min. is likely to be insufficient, especially when considering the need for additional use of inter-dental cleaning devices. In patients with gingivitis once daily inter-dental cleaning is recommended and the adjunctive use of chemical plaque control agents offers advantages in this group.’8

The ‘Delivering better oral health’ toolkit offers further advice, in relation to controlling risk factors for periodontal disease in adults, as follows:

• Do not smoke – smoking increases the risk of periodontal disease, reduces benefits of treatment and increases the chance of losing teeth. Dental health care professionals (DCHPs) should therefore take a history of tobacco use, offer brief advice on how to quit, and provide details of a local stop smoking service.9

• Patients with diabetes should try to maintain good diabetes control as they are: - At greater risk of developing serious periodontal disease - Less likely to benefit from periodontal treatment if the diabetes is not well controlled Because of this, DHCPs should explain to patients the risks related to diabetes.9

• Some medications can affect gingival health As a result, DHCPs need to ascertain if a patient is taking any medication that may cause xerostomia or gingival enlargement, and explain the risks, as well as providing a clinical assessment and management guidance.9

Cause and effect, Offering an overview of the situation, Chapple and colleagues (2017) wrote that, since periodontal disease has multiple causes, ‘[…] the correction of one risk factor may not lead to disease cure. It is important to state that increased risk does not necessarily imply causation, as certain factors may increase susceptibility to a disease developing, but may not fulfil all the requirements required for a causal factor. For this, temporal associations between the risk factor and disease onset should be established, with the risk factor arising prior to the disease onset; the risk factor also being associated with an increased frequency of the disease within a population; biological mechanistic plausibility regarding how the risk factor may contribute to disease onset; and evidence that risk factor management leads to improvement in the disease or its resolution.’4

It would seem, therefore, that, as multifactorial diseases, gingivitis and periodontitis should be considered holistically, and any dental treatment and preventive advice be tailored to those causes assessed to have the potential to affect a patient’s soft tissue health detrimentally.



  1. A Dictionary of Dentistry (Ed: Ireland R). Oxford University Press 2010; 274
  2. Page RC, Kornman KS. The pathogenesis of human periodontitis: an introduction. Periodontology 2000 1997; 14: 9-11
  3. Scully C. Churchill's Pocketbooks. Clinical Dentistry. Churchill Livingstone, 4th edition, 2016; 465
  4. Chapple ILC et al. Interaction of lifestyle, behaviour or systemic diseases with dental caries and periodontal diseases: consensus report of group 2 of the joint EFP/ORCA workshop on the boundaries between caries and periodontal diseases. J Clin Periodontol 2017; 44 (Suppl. 18): S39-S51
  5. UK Adult Dental Health Survey 2009. The Information Centre for Health and Social Care 2011
  6. Kinane DF, Attström R. Advances in the pathogenesis of periodontitis. Group B consensus report of the fifth European workshop in periodontology. J Clin Periodontol 2005; 32(Suppl. 6): 130-1
  7. Boyle P et al. Mouthwash use and the prevention of plaque, gingivitis and caries. Head & Neck Oral Diseases 2014; 20(1): 1-76
  8. Chapple ILC et al. Primary prevention of periodontitis: managing gingivitis. J Clin Periodontol 2015; 42 (Suppl. 16): S71–S76
  9. Delivering better oral health: an evidence-based toolkit for prevention. Public Health England, 3rd edition, updated 2017