The first phase is to determine caries risk, which may vary throughout a patient’s lifetime. Risks can be classified as clinical, medical, social and behavioural. They are in turn used to determine a risk status for a patient; this can be low, moderate or high. The first stage in management of dental caries is to address any modifiable risk factors. Clinical risks are those that can be assessed by directly examining the patient and include recent past caries experience, the pres­ence of active caries and inadequate oral hygiene, including visible stagnation of plaque biofilm. It is also possible to identify clinically whether or not the patient has oral dry­ness (xerostomia). Xerostomia may be present for a variety of reasons, including medical conditions, such as Sjogren’s syndrome or previous damage to salivary glands from head and neck radiotherapy, or as a result of certain medica­tions, e.g. tricyclic antidepressants, antihistamines, anti­muscarinics or recreational drugs. Social, medical and be­havioural risks include diet, social status, compliance with hygiene practices, dental attendance patterns and other special educational needs or physical disabilities. Obvious milestones in a patient’s life, e.g. reliance on caregivers to prepare food and drinks, as well as help with oral hygiene practices either early or later in life, or adapting to indepen­dent living can all impact on caries risk. The most fre­quently encountered risk factor is a high intake (both amount and frequency) of free sugars in meals, snacks or drinks. The timing of sugar consumption in relation to meals and bedtime is also important and should be ascer­tained. High sugar consumption is a common risk factor for obesity, diabetes and cardiovascular disease, and the patient should be made aware of the potential impact on their gen­eral, as well as their oral, health.

Caries is not limited to the coronal aspect of a tooth and can occur on the root surfaces of teeth where there are areas of exposed dentine and cementum. Exposed areas of dentine are more prone to caries than enamel due to the higher (less acidic) critical pH of demineralisation of dentine (pH 6–6.5 compared with pH 5.5 for enamel). Therefore, the preva­lence of root caries increases with age as a consequence of older adults retaining more of their teeth for longer which may have been subjected to periodontal bone loss and reces­sion. The surfaces that are most susceptible are those that are prone to plaque accumulation and stagnation, which may be greater in interproximal sites, around fixed and re­movable prostheses and may not be removed effectively. Older adults are more likely to be medically compromised and as a result may have poorer manual dexterity. Treat­ment for root caries therefore will likely focus on prevention and minimally invasive treatment approaches.

Matrices can be used to help rebuild teeth where walls have been lost. These come in numerous shapes and sizes, from specific putty matrices (commonly used to help rebuild an­terior teeth – see later), to generic metal and clear matrices, which may be contoured or flat, and sectional or circumfer­ential. Sectional matrices, which are commonly contoured, used in conjunction with wooden wedges to seal cavity boxes and provide separation of the teeth, are very useful to achieve contact points both anteriorly and posteriorly with composite, which can be difficult if not impossible to achieve with circumferential bands due to the relatively passive nature of composite placement. This can also be facilitated by the use of separating rings (Fig. 3.3). Given that amal­gam is actively packed during placement, contact points can be achieved much more easily with the use of bur­nished circumferential bands.