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Root Surface Caries – an age-old problem?

In many industrialised countries, as birth rates fall and life expectancy increases, the proportion of older adults within the population is increasing. This trend is predicted to continue throughout the twenty first century[i]. Although prevalence of chronic medical conditions is high in this cohort, large longitudinal populations studies into ageing have shown that an increasing number of older adults are living independently and are mobile and active in their communities.[ii],[iii],[iv]. With increasing numbers of patients retaining their natural dentition into old age, the immense challenges of providing dental care for this population will increase. An increase in exposed root surfaces in the over 65 age group predisposes this cohort to a higher prevalence of root caries than younger populations[v]. We know that masticatory function is of particular importance for older adults. Healthy oral ageing is important to healthy ageing from both biological and social perspectives.  Maintenance of a nutritionally complete diet is important for avoiding sarcopenia and the frailty syndrome. Successful oral ageing then is associated with adequate function and comfort. A reduced, but functional, dentition of 20 teeth in occlusion has been proposed as a measure of successful oral aging. [vi]

The Role of Oral Hygiene

The mouth is clearly not a uniform environment but contains many distinct micro-environments, some of which are more conducive than others to developing dental disease.  Effective oral hygiene advice is tailored and takes into account the different needs in each area of the mouth as well as the very specific needs of the individual concerned. 

We know that dental caries is a complex process in which the colonisation of the tooth surfaces by bacterial plaque is an essential prerequisite for the development of the disease. Consequently, mechanical plaque removal could constitute a basic preventive measure. However, the predilection sites for the development of dental caries ie, the interdental surfaces and the fissures and pits are the sites most difficult to reach with mechanical plaque control measures. Many of the case studies concerned with the effects of the mechanical plaque control per se involve the simultaneous application of fluorides. Therefore, the respective role of these two elements is difficult to identify. However, there is good evidence supporting the fact that mechanical plaque removal in itself decreases the incidence of interdental caries.vii A recent study published in the Journal of Dentistry identified and concluded that poor plaque control was one of the strongest predictors of risk for root surface caries.viii

Caries is a preventable disease and so whilst this article will provide an overview of this classification of caries we also need to consider the role of the entire dental teams including deliverers of health education in working towards its prevention.

Root surface Caries

Root caries is a decayed lesion located on the root surface of a tooth, usually close to or below the gingival margin. Our ageing population has meant that root caries has become an important dental problem because people are living longer and keeping their teeth longer. As patients grow older, their gums recede and root surfaces are exposed, making them more susceptible to root caries. Any caries-prone patient having gingival recession can develop root caries. However, older adults are usually more vulnerable to root caries because of multiple medical conditions and their associated polypharmacy. The loss or reduction in the protective function of saliva from whatever cause, helps promote an oral environment that favours the caries process.

Dietary changes as a result of altered taste sensation, inability to prepare food themselves or simply ease of eating all add to the risk potential.

Distribution within the Mouth

Root caries most often occurs supra-gingivally, at or close to (within 2 mm) the cemento-enamel junction There is a characteristic distribution for root caries lesions within the oral cavity.

Mandibular molars are most effected followed by maxillary anterior teeth & maxillary posteriors. Mandibular anterior’s seem to be least susceptible. The buccal and interproximal surfaces are more susceptible than the palatal or lingual aspect of affected teeth[ix]

The role of Saliva

We know that presence of saliva is vital to the maintenance of healthy oral tissues. Reduction of salivary output not only results in a rapid deterioration in oral health but has a massive impact on the quality of life of the sufferer.  Many of the commonly prescribed drugs given to manage the plethora of medical conditions associated with aging cause a reduction in salivary flow. Xerostomia then, is a problem that faces an increasingly large proportion of the population. 

The demineralising effects of the organic acids produced in dental plaque by microorganism that ferment carbohydrates, most notably sucrose, cause caries. Studies have shown that sucrose ingested in several different forms is distributed very unevenly around the mouth and is cleared at very different rates at different locationsx. In general, clearance is more rapid from lingual than from buccal tooth surfaces, except buccal to the upper molars where parotid saliva enters the mouth. Apart from that region, buccal tooth surfaces are mostly exposed to the extremely viscous secretions from the minor mucous glands.

Risk factors

Risk factors associated with the high prevalence of root caries among older adults include:

  • Decrease salivary flow or xerostomia, 
  • Exposure of root surfaces due to periodontal (gum) disease, 
  • Chronic medical conditions, 
  • Radiation treatment for head and neck cancer, 
  • Physical limitations, 
  • Diminished manual dexterity due to stroke, arthritis, or Parkinson's disease, 
  • Cognitive deficits due to mental illness, depression, Alzheimer's disease or dementia, Sjögren's syndrome (an autoimmune disease), 
  • Diabetes, 
  • Poor oral hygiene, 
  • Multiple medication use, 
  • Changes in dietary habits. 
  • Previous root caries experience, either in the form of filled surfaces or decayed untreated lesions is also a potent risk factor for the development of new lesionsxi
  • Serum albumin concentration: A. Yoshihara (2003) conducted a study to evaluate, by serum albumin concentrations, the relationship between the general health condition and root caries. The findings of the study indicated that a relationship between root caries and serum albumin concentration in these elderly subjects is highly possible.xii

What makes this form of caries so difficult to manage?

  • It has a comparatively rapid progression
  • It is often asymptomatic
  • It is closer to the pulp
  • It is technically more difficult to restore.

With our changing age demographic, the mantra of oral health care teams, as the population ages and resources become limited, is to find progressive diseases like dental decay early enough to start effective treatment before irreversible damage has occurred. Training in learning how to engage the patient so that compliance and trust are maximized needs to become the bedrock of dental training in all disciplines. The role of diet on disease whilst very much in the popular press in relation to obesity needs to address sugar as a common risk factor for the most common of all preventable disease – tooth decay….

Teaching and encouraging patients to take ownership of their oral health is the answer here allocating time in practice for prevention and education is the ideal. Time is money but prevention is cheaper and more preferable than cure in the long run as we all appreciate. Sharing the burden of increasing the awareness of the importance of oral health is done well by our commercial partners – after all, fluoride toothpaste has arguably had the biggest impact on the overall reduction in the UK caries rate to date.

The development of new and adaptation of existing oral hygiene aids, to meet the needs of older adults, will be key to helping to reduce the incidence of dental disease in this group.

Prevention is everyone’s responsibility, the profession, the patient and the wider commercial sector – all of whom are stakeholders.

[i] J Banks, J Nazroo, A Steptoe, The Dynamics of Ageing: Evidence from the English Longitudinal Study of Agiveing 2002-2010. (Wave 5) . IFS 2012
[ii] MJS Kelly, N Nuttall, G Bradnock, J Morris, J Nunn, C Pine, N Pitts, E Treasure, D White,. Adult Dental Health Survey of Oral Health in the United Kingdom. The Stationary Office . London, 1998
[iii] Lamster IB, Asadourian L, Del Carmen T, Friedman PK.  The aging mouth; differentiating normal aging from disease.  Periodontal 2000; 2016 Oct 72 (1): 96 -107
[iv] B Gupta, C Marya, V Juneja, V Dahiya. Root Caries: An Aging Problem. The Internet Journal of Dental cience. 2006 Volume 5 Number 1.
[v] M Hayes, C Da Mata, M Cole, G McKenna, F Burke, P Finbarr Allen, Risk indicators associated with root surface cares in independently living older adults. Journal of Dent.  2016 51: 8-14
[vi] Banting DW, Ellen RP, Fillery ED. Prevalence of root surface caries among institutionalized older persons. Community Dent Oral Epidemiol. 1980;8:84-88.
[vii] Britse A, Lagerlof F. The diluting effect of saliva on the sucrose concentration in different parts of the human mouth after a mouth rinse with sucrose. J Dent Rest 1999; 68; 1479-1482
[viii] Vehkalahti MM, Rajala M, Tuominen R, Paunio I. Prevalence of root caries in the adult Finnish population. Community Dent Oral Epidemiol. 1983;11:188-190.
[ix] J J Murray.The prevention of oral disease. Third edition .Oxford university press1996:174-181.
[x] Banting D.W. (2001). The Diagnosis of Root Caries Retrieved 9 Oct, 2009 from www.nidcr.nih.gov/NR/rdonlyres/5A4386A8-E750-43E9-8450-651F4789D09A/0/David_Banting.pdf