Plaque biofilm – dealing with a microbial community
Johnson & Johnson is delighted to bring you this article, with the aim of supporting the ongoing CPD needs of dental healthcare professionals in improving and maintaining the oral health of their patients.
This article is equivalent to one hour of Enhanced CPD. To provide feedback on this article, please contact firstname.lastname@example.org
Aims and objectives
The aim of this article is to revisit the main causes of periodontal disease, explore the evidence supporting an effective three-step home-care regimen and look at up-and-coming preventive options that may prove themselves worthy in the near future as an adjunct to mechanical cleaning.
On completing this Enhanced CPD session, the reader will:
• Understand that the causes of periodontal disease are multi-factorial and how the microbial community in the oral cavity may contribute
• Understand the continuum from gingivitis to periodontitis and at what point to take preventive action
• Understand what constitutes good periodontal health and how to help patients work towards achieving it
• Understand future preventive possibilities in relation to periodontal disease.
Plaque biofilm – dealing with a microbial community
This article revisits the main causes of periodontal disease, explores the evidence supporting an effective three-step home-care regimen and looks at up-and-coming preventive options that may prove themselves worthy in the near future as an adjunct to mechanical cleaning.
The Adult Dental Health Survey of 2009 indicates that 83% of dentate adults show some evidence of periodontal disease (that is bleeding, calculus, periodontal pocketing of 4mm or more and in the case of adults aged 55 or above, loss of periodontal attachment of 4mm or more anywhere in their mouth).1
Focusing on periodontal disease, Group B of the 5th European Workshop in Periodontology deemed gingivitis and periodontitis to be a ‘continuum’ of the same inflammatory disease. However, gingivitis will not always progress to periodontitis, since, ‘The weight of the evidence indicates that the prevention of gingival inflammation prevents periodontitis’.2
More recently, Chapple and colleagues (2017) wrote: ‘Periodontal diseases … 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.’3
Also considering the microbial community in the mouth, Chapple and colleagues (2017) went on to state, ‘… there is a symbiosis between a health-associated biofilm and a proportionate host immune inflammatory response. Periodontitis develops following the emergence of a dysbiosis in susceptible individuals which is associated with dysregulation of the immune-inflammatory response, and which leads to host mediated connective tissue damage and alveolar bone loss.’3
In addition, untreated periodontal disease may result in, ‘[…] tooth loss, reduced masticatory function, poorer nutritional status, low self-esteem and quality of life, negative general health impacts. There is also evidence of an association with higher all-cause mortality.’3
Given all of this, preventing the progression of periodontal disease and maintaining a good level of oral health is paramount but not necessarily easy. Given the low level of healthy periodontal tissue, as highlighted in the Adult Dental Health Survey 2009, despite three-quarters of respondents claiming to brush twice-daily and one-quarter of those saying they clean interdentally every day,1 there appears to be an unmet oral health need.
What is good oral health?
For dental professionals to move forwards in their preventive endeavours, it may be helpful to consider first what constitutes a good level of oral health.
The World Health Organization considers: ‘Health is a state of complete physical, mental and social wellbeing and not merely the absence of disease or infirmity.’4
Applying this to periodontal health, Chapple and colleagues (2018) wrote: ‘…periodontal health should be defined as a state free from inflammatory periodontal disease that allows an individual to function normally and avoid consequences (mental or physical) due to current or past disease. Based upon this overall framework of health, periodontal health should be predicated upon the absence of disease…’.4
In line with this, Tonetti and colleagues (2015) considered the importance of acting as soon as gingivitis has been diagnosed, suggesting: ‘Gingivitis and periodontitis are inflammatory conditions caused by the formation and persistence of microbial biofilms on the hard, nonshedding surfaces of teeth. Gingivitis is the first manifestation of the inflammatory response to the biofilm. It is reversible (i.e. if the biofilm is disrupted gingivitis resolves), but if biofilms persist gingivitis becomes chronic. In some subjects, chronic gingivitis progresses to periodontitis.’5
They also wrote: ‘Periodontitis is characterized by non-reversible tissue destruction resulting in progressive loss of attachment eventually leading to tooth loss.’5
Therefore, if gingivitis is not resolved in a patient, it may develop into the irreversible, more destructive periodontitis: ‘Primary prevention of gingivitis aims to avoid the development of more severe and widespread forms of gingivitis that may ultimately convert to periodontitis.’5
Adding to this picture, Birch and colleagues (2015) wrote: ‘Primary prevention of gingivitis should be a key aim of dental professionals, to maintain non-inflamed, healthy tissues. If gingivitis is identified, treatment should be provided to resolve the gingivitis, as this is a preventive strategy for preventing progression to periodontitis.’6
Three steps to success
Intervention, therefore, is essential and, offering practical insight on this issue, Khan and colleagues (2015) stated: ‘The primary goal of periodontal treatment is to restore the homeostatic relationship between periodontal tissue and its polymicrobial dental-plaque community. Therefore, prevention and treatment are primarily aimed at controlling the bacterial biofilm and other risk factors, arresting progressive disease, and restoring lost tooth support. The most widely used treatment is physical removal of the plaque by scaling. Therefore, establishing proper oral hygiene by practicing daily measures such as brushing, flossing, using an antiseptic mouthwash, and regular dental check-ups is the cornerstone for successful prevention and treatment of periodontal diseases.’7
Whilst it is widely accepted that twice-daily brushing and interdental cleaning are essential in helping to control the plaque-mediated conditions of periodontal disease, there are limitations.8
Boyle and colleagues (2014) offered clarification on this issue writing: ‘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.’9
In 2015, Working Group 2 of the 11th European Workshop in Periodontology agreed that a third step may be needed, writing: ‘For the treatment of gingivitis and where improvements in plaque control are required, adjunctive use of antiplaque chemical agents may be considered. In this scenario, mouth rinses may offer greater efficacy but require an additional action to the mechanical oral hygiene regime.’10
Further, Serrano and colleagues (2015) suggested that: ‘The adjunctive use of chemical plaque control, together with mechanical control, offers advantages […] in plaque levels control.’11
They added: ‘When it comes to the selection of a proper format to deliver the antiseptic agent, the results suggest that mouthrinses may provide better results.’11
The possibilities in terms of periodontal treatment are ever-evolving, with a number of issues currently being investigated, including microbial-focused studies such as host modulation of inflammation and bacteria, and host versus pathogens in the pathogenesis of periodontitis.12
Epigenetics – the study of changes in organisms caused by modification of gene expression rather than alteration of the genetic code itself – have also sparked interest.12,13
In a UK-based, cross-sectional study, Kurushima and colleagues (2019) found: ‘Epigenome-wide analyses and a candidate gene approach in adult female twins identified differentially methylated signals in periodontal disease. In conjunction with transcriptomics and metabolomics analyses, we conclude that the epigenetic changes may have functional regulatory effects over the course of development and progression of periodontal disease.’14
Although further research is needed, this outcome suggests that in the future it may be possible to use DNA methylation profiles in creating personalised treatment and prevention plans to address periodontal disease even before it strikes, for instance to identify patients at high risk for whom anticipatory changes to risk factors could be made.14
Natural therapies are being researched too, such as probiotics, fish oils and vitamin D, to name just three currently of interest to academics.3,12
Chapple and colleagues (2017) considered the role of such therapies, suggesting ‘Functional foods or probiotics could be helpful in … periodontal disease management, although evidence is limited and biological mechanisms not fully elucidated.’3
Adding to this possibility, Jayaraj and colleagues (2017) wrote: ‘The concept of probiotics promotes a new horizon on the relationship between diet and oral health. […] Randomized controlled trials and systematic studies needs to be done to find out the best probiotic strains and means of their administration in different oral health conditions.’15
Fish oil (a rich source of Omega 3 fatty acids), meanwhile, have proven antioxidant properties, which are able to reduce inflammation by via immunomodulatory activity.16,17
Investigating the effects of food supplements on periodontal status and local and systemic inflammation after non-operative periodontal treatment, Rasperini and colleagues (2019) found that, ‘DHA Omega 3 (Resolvine) has important antioxidant functions, protects cells from aging and moderates anti-inflammatory mechanisms reducing the protein levels of inflammatory cytokines… In patients with chronic periodontal disease treated with a non-surgical approach, the adjunctive administration of omega-3 PUFAs [polyunsaturated fatty acids] and low-dose aspirin improved periodontal clinical parameters … compared with the control treatment (SRP + placebo).’16
As for Vitamin D, Working Group 2 of the 1st joint European Workshop on the boundaries between caries and periodontal diseases (2017) wrote: ‘Whilst there is conflicting evidence relating to vitamin D intake and serum levels to periodontal health…, vitamin D supplementation combined with calcium has been shown to reduce tooth loss and improve periodontal health.’3
A holistic approach
As stated by the FDI Global Periodontal Health Project Task Team (2018): ‘The role of different bacterial species in the subgingival biofilm as the primary aetiological factor in periodontitis is indisputable. The microbiological characteristics of periodontitis show significant changes from those in periodontal health with co-association of different organisms into consortia, representing the critical shift of the oral microbiome from symbiotic states to dysbiotic ones. It is worth noting that host response plays an important role in the pathogenesis of periodontal diseases. Indeed, the dysregulation of immuno-inflammatory pathways is crucial for persistent periodontitis lesions.’18
Although interaction between the host and the microbial community has been acknowledged as a key element in the development of periodontal disease, the fact remains that multi-factorial and modifiable risk factors (e.g. smoking, obesity, socio-economic status, etc.) also need to be considered when working to stop gingivitis in it tracks before it has the opportunity to develop into more destructive and non-curable periodontitis.18,19,20
Adult Dental Health Survey 2009. Health and Social Care Information Centre 2011