Commentary

Ageing of the population will result in an increase in the incidence of root caries as it has been shown that elderly patients are at a higher risk of root caries than younger populations.1 Root caries lesions frequently exhibit mixed cavity margins positioned in enamel as well as dentine, and restoration of this cavity type is challenging with respect to the lack of restorative materials which bond equally well to both dental tissues. The evidence base for the choice of restorative material for root caries lesions is neither plentiful nor convincing and studies have reported failure rates as high as 68% within 12 months.2,3 In light of this, prevention or remineralisation of these lesions is highly desirable for patients and clinicians alike.

This systematic review aimed to compare chemical agents in the prevention of new caries on root surfaces or to inactivate existing lesions. PubMed, EMBASE and the Cochrane Central Register of Controlled Trials were searched for clinical trials which utilised preventive dental regimes and/or one or more chemical agents applied by a dental professional or by the patient themselves. Thirty-four articles were included reporting 30 trials with 10,136 patients and analysing 28 chemical agents. These chemical agents were dentifrices (eleven studies), rinses (ten studies), varnishes (eight studies), fluoride solutions (three studies), gels (three studies) and ozone (two studies). One study investigated a preventive regime without any chemical agent.

Meta-analyses were performed where possible, however once the studies were subdivided the number of studies in each analysis were very small (two to four studies), and the number of events in each group was low. Many of the trials had a short follow-up time of less than one year.

Also, results were reported at the tooth or root surface level and it must be remembered that these events are not independent of each other if multiple new carious lesions develop within one individual. Studies also utilised different diagnostic criteria in the identification of root caries and the level of activity of these lesions. This presents difficulty when conducting any meta-analyses of these trials.

The authors of this systematic review concluded that dentifrice containing 5,000 ppm fluoride and professionally applied chlorhexidine or silver diamine fluoride varnishes may inactivate existing and/or reduce the initiation of root caries. However they caution the reader that this is based on a low number of clinical trials which have a high risk of bias. While this review attempts to answer a timely and important clinical question, the number of chemical agents reported across the literature was large and no single intervention can be identified as our current ‘gold standard’ for the prevention or remineralisation of carious lesions on root surfaces.

Practice points

  • Root caries can be prevented or arrested using topically applied agents. These can be applied by a dental professional or by the patient themselves.

  • Based on the evidence available, patients at risk of developing root caries or who have existing root caries may benefit from daily use of a prescription strength toothpaste which will deliver 5000ppm fluoride or professional application of a chlorhexidine or silver diamine fluoride containing varnish.