The proportion of older people in the population is growing and their inadequate plaque control procedures make root caries an increasingly common oral health problem. Soft tissue recession due to age, traumatic tooth brushing habits, periodontal disease or periodontal treatment will unavoidably result in more tooth root surfaces that are at risk for the development of root caries. Restorative treatment of root caries is notoriously difficult. Post-treatment pain and hypersensitivity are very common, and this may contribute to increased tooth loss in many people with root caries.

A systematic review examining the effectiveness of fluoride in preventing dental caries in adults found fluoride (self- and professionally applied or water fluoridation) annually averted 0.29 carious coronal and 0.22 carious root surfaces, and concluded fluoride is effective among adults of all ages.1 A systematic review of preventive interventions for root caries also showed that additional fluoride appears to be a preventive and therapeutic treatment for root caries.2 A recent randomised controlled trial (RCT) in elderly disabled nursing home residents in Denmark has found that 5000 ppm F toothpaste is significantly more effective for controlling root caries lesion progression and promoting remineralisation compared to 1450 ppm F toothpaste.3

The aim of this RCT was to evaluate the effectiveness of high-fluoride toothpaste (5000 ppm F) on root caries lesions in adults and to test the hypothesis that high concentration fluoride toothpaste would effectively improve the surface hardness in root caries lesions in adult patients. The results of this study do suggest a statistical benefit at both three and six months from the use of 5000 ppm F toothpaste. Although the methodology of this RCT is robust, there were a few limitations as highlighted by the authors in their discussion. It was not possible to produce identical packages for the test and control toothpaste. Consequently, the patients were aware of their group assignment although the outcome assessors were blind. Another shortcoming was the failure to recruit the sample size of 90 per group proposed by the power calculation. The power was not adequate to demonstrate that the high-fluoride group improved surface hardness better than the lower-fluoride group over time.

While reporting of this RCT follows closely the CONSORT statement (, there was no mention of any harms or unintended effects in each group. It would be helpful to state the absence of any adverse events even if none occurred. This is particularly important, as high-fluoride toothpaste is a prescription only medicine. Many patients who require the use of high-fluoride toothpaste may have special needs and find spitting out the toothpaste difficult. This may result in chronic ingestion of toothpaste and lead to fluoride toxicity.4

As with most trials, the participants recruited were a highly selective group, and/so the generalisability of the findings of this study is not certain. While we have strong evidence of effectiveness of fluoride toothpaste in children and adolescents5 only a small number of studies have been conducted in adults. While this study suggests a benefit from the use of the higher concentration fluoride toothpaste in adults in the short term, more information is required to better inform our adult patients on their use. The extra cost of prescription toothpaste can be a hurdle for some patients.

Practice point

  • Dental practitioners should consider prescribing higher concentration fluoride toothpaste (5000 ppm F) for patients with root caries lesions

  • Repeat prescriptions of high-fluoride toothpaste should not be dispensed without reassessing the patient.