Caries and the older patient

Primary caries

Primary caries in older adults can present in any tooth surface but it is more commonly seen on cervical areas (Figure 1) and the root surface. Caries can also be seen in susceptible pits and fissures if these have not experienced the disease in the past and therefore have not undergone restoration.

Secondary caries

Elderly patients who experienced caries in the past may present with large restorations which may eventually fail. It is known that 60% of restorations placed by practitioners are to replace failed restorations and the most common cause for replacing restorations is secondary caries.6 Hence the importance of applying minimally invasive procedures whenever possible to minimize restoration size.

Root caries

Recession of the gingival margin is a common finding among older patients.7 As the gingival margin recedes, the enamel-cementum junction becomes exposed. This is a very irregular site which can be susceptible to bacterial retention and root caries can develop. Cementum and dentine on the root are less mineralized than enamel and, as such, may be more susceptible to demineralization.

Root caries can present ranging from very small, softened and discoloured areas to extensive, yellow-brown soft or hard areas that may sometimes encircle the whole root surface.

It is important to differentiate between active root caries and arrested lesions. An active lesion is a well-defined, softened area on the root surface that is close to the gingival margin. The lesions are usually covered with plaque. An arrested root surface lesion, on the other hand, appears shiny, hard and is further from the gingival margin.

Both active and inactive lesions can be cavitated. It is important to distinguish between these two entities in order to provide the most appropriate treatment option. Active lesions can become arrested if oral hygiene measures are improved, with associated change in texture. Cavitated lesions must be restored if they represent a site of plaque accumulation which results in difficulty in cleaning (Figures 2 and 3).

Caries on overdenture abutments

Overdenture therapy has become an accepted alternative to extraction of all remaining teeth in older patients. Development of caries in these overdenture abutments is a significant problem and can result in abutment failure. The highest risk of failure can be associated with inadequate oral hygiene and failure to use fluoride consistently.8

General health

The patient's general health plays a key role in his/her oral health maintenance. An older adult's decreased mobility, manual dexterity and impaired vision can affect his/her ability to follow instructions and perform oral hygiene activities (Figure 3). Motivation to perform these activities may also become limited. It is very important to know and include all these details in the patient's history to be able to propose alternatives.

A patient with manual dexterity problems, for example, can receive an adapted toothbrush to make oral hygiene easier. In the case of patients who have a carer or helper, it is important to have this person present at the dental appointments and give them all the oral hygiene instructions together with the patient. Motivation is key and the carer needs to be aware of his/her role in ensuring oral hygiene and that preventive methods must become part of the patient's routine.

Xerostomia

Saliva is essential for tasting and enjoying food and has a key role on lubrication and protection of soft and hard tissues. Its antibacterial properties maintain the balance of the oral flora. It is also important to keep the mouth relatively clean as it washes away food debris. Therefore, a dry mouth is a risk factor and can result in dental caries.

Approximately 30% of the population aged 65 or over suffer from dry mouth.10 Drug-induced xerostomia is most common in old age and related to several drugs usually taken by this group of patients, such as tricyclic antidepressants, beta blockers and antihistamines.

A patient's salivary flow should be assessed through simple questions about self perceived xerostomia (Does your mouth feel dry? How often?) and examination (Does the mirror stick to buccal mucosa? Does the mouth look dry?). The use of saliva substitutes, mouth moisturizers and sugar-free chewing gums can then be suggested.

Diet

A high-sugar-content diet can result in tooth decay. Older patients might be on a more cariogenic diet or taking medications which contain great amounts of sugar. Assessing type and frequency of food intake is important, although proposing changes to older individuals can be quite challenging. It is essential to know if the diet represents a risk in order to plan the most appropriate treatment and preventive strategy.

Oral hygiene habits/fluoride exposure

Frequent toothbrushing with the use of fluoride-containing toothpastes is of great importance to avoid initiation of the caries lesion and also to promote remineralization of affected enamel, dentine or cementum.

The older adults of today come from an era when the knowledge about the caries process was scarce and oral health promotion programmes non-existent. Hence, some of them might not know how to brush their teeth properly or use the incorrect products to do so.

Past dental history

Patients who have a high number of filled and missing teeth, who live in non-fluoridated areas, partial denture wearers and who are not regular dental attendees can also be considered at a higher risk for dental caries. The past disease experience will also give an indication of caries risk.

Caries prevention

Evidence suggests the management of dental caries needs to move to less invasive approaches (Table 1). All effort must be made to prevent the disease from occurring and patients have to be educated in that direction. Older patients have not benefited from oral health programmes in the past and clinical studies suggest that oral health education for these patients can be effective.3

If a caries lesion is present, treatment will depend on the stage of the disease. In non-cavitated lesions, the oral environment may be altered to allow remineralization. This approach includes decreasing the frequency of refined carbohydrate intake, improving plaque control, ensuring optimum salivary flow and conducting patient education. Topical fluorides can be used to encourage remineralization.

In cavitated lesions, a surgical approach is indicated but should be minimally invasive. Infected tissue should be removed and replaced with an appropriate filling material.

Before any surgical intervention is undertaken, it is fundamental to establish a plan for disease control. This will involve moving patients from high to low risk status and promoting remineralization of early lesions. Any changes in oral hygiene technique, frequency of food intake, use of topical fluoride or saliva substitutes should be discussed and suggested at this stage.

Conventional restorations

Adhesive restorative materials and techniques result in less removal of healthy tissue.12 Composite resins may be indicated when aesthetics and strength are important. In situations where field control is not adequate, glass ionomer cement can be used more successfully. A conventional or resin-modified glass ionomer can be used to restore root caries.

Glass ionomer cement

As with composite resin, adequate isolation, use of matrices and strips is recommended to ensure optimum placement of glass ionomer cements. After caries removal, the cavity should be conditioned for 10 seconds using 10% polyacrylic acid to remove the smear layer and, after washing the cavity, it is important not to over-dry it. After the glass ionomer cement is mixed and placed into the cavity, a barrier should be used to avoid water exchange. Petroleum jelly or a light-activated resin enamel bond can be used for that purpose. Conventional glass ionomer cement should not be polished for at least 24 hours after the restoration is placed, whereas resin-modified glass ionomer cement can be finished immediately.

Atraumatic Restorative Treatment (ART)

ART involves the use of hand instruments only to remove caries and an adhesive material such as glass ionomer cement to restore the tooth. Only the very soft, infected dentine is removed and the cavity is sealed, which will allow remineralization. This is a technique which does not require the use of anaesthesia or rotary instruments. It has been used in children with success and studies show survival rates comparable to conventional techniques.13 ART can be very useful in treating older patients, especially those who have restricted mobility, who require domiciliary care or who have a dental phobia. It can also be a response to the challenge of restoring root lesions (Figures 4 and 5). High survival rates of ART to treat root caries have been reported in the literature.14

The technique entails:

Repair of defective restorations

When treating secondary caries, whenever it is possible, it is more conservative to repair rather than replace the restoration (Figures 6 and 7). The replacement of amalgam and composite restorations result in loss of tooth structure and larger restorations, which will have shorter life spans than their predecessors.6 Some studies suggest that repair of restorations may prove to be as effective as replacement but evidence is still weak and incomplete.15 Thus, the decision of repairing a restoration must be based on a patient's risk for caries, professional judgement of benefits versus risks and minimally invasive principles of cavity preparation. Long-term success of the repair will depend on the patient shifting to a low risk status. It is important to keep in mind, though, that a decision of ‘no treatment’ rather than ‘replacement’ of a restoration is more likely to be correct in a low risk population.