Tooth decay is a very common disease that over time destroys the tooth surface. It has been estimated to affect up to 80% of people in high-income countries and, despite being preventable through oral hygiene and dietary measures and the use of agents such as fluoride that reduce risk of decay, it is likely to remain a problem, especially in low-income countries. Tooth decay can result in pain and infection, and in young children may require treatment in hospital under a general anaesthetic. As well as causing anxiety and pain, this may mean the child or young person missing time at school and their parents or carers having to take time off work, possibly losing income and incurring extra costs. Prevention of tooth decay is simpler and possibly cheaper than waiting until it occurs and then requires extensive treatment. Tooth decay is largely preventable, and a range of things may assist this: twice-daily toothbrushing with a fluoride toothpaste, and reducing both the amount of and number of times per day sugar is eaten. Tooth decay occurs when certain types of bacteria (germs) in the mouth, such as Streptococcus mutans, produce acids from the sugar we eat, which dissolve the hard enamel coating on our teeth. Some studies have shown that the chemical antiseptic treatment chlorhexidine is highly successful at destroying these bacteria and can be used safely at home in the form of a gel, spray, chewing gum, toothpaste or mouthrinse. Alternatively, chlorhexidine can be applied as a varnish to the surface of teeth by a dentist. But what is the evidence that it works to reduce tooth decay in children?
What was the research?
A systematic review of the evidence to find out the effectiveness of varnishes and gels containing chlorhexidine in preventing tooth decay in children and young people
Who conducted the research?
The research was conducted by a team led by Tanya Walsh from the University of Manchester, on behalf of the Cochrane Oral Health Group. Jeronimo M. Oliveira-Neto and Deborah Moore were also on the team.
What evidence was included in the review?
Data was extracted from 8 randomised controlled trials. A total of 2,876 children under 15 years participated in the trials, and were randomly assigned to:
1. Chlorhexidine varnish versus no treatment (6 trials)
2. Chlorhexidine gel versus no treatment (2 trials)
What did the evidence say?
The results did not provide evidence that chlorhexidine varnish or gel reduces tooth decay or reduces the bacteria that encourage tooth decay. The studies did not evaluate other outcomes such as pain, quality of life, patient satisfaction or direct and indirect costs of interventions. Four studies measured side effects and found none were observed.
How good was the evidence?
Due to the lack of suitable studies and concerns about possible bias in the included studies, the evidence is very low quality.
What are the implications for dentists and the general public?
We are not able to conclude whether or not chlorhexidine is effective in preventing tooth decay in children or adolescents, when compared to placebo (an inactive substitute for chlorhexidine) or no treatment.
What should researchers look at in the future?
Future research on the use of chlorhexidine to prevent tooth decay is needed and should consider both primary (milk) and permanent (adult) teeth and should assess other chlorhexidine-containing products that can be used at home, such as toothpastes or mouthrinses.
Walsh T, Oliveira-Neto JM, Moore D. Chlorhexidine treatment for the prevention of dental caries in children and adolescents. Cochrane Database of Systematic Reviews 2015, Issue 4. Art. No.: CD008457. DOI: 10.1002/14651858.CD008457.pub2.