This is a plain English summary of an original research article. The views expressed are those of the author or reviewers at the time of publication.
Dentists invite most people for a dental checkup every six months. Despite being common practice in the UK and many other countries, this interval is based on low-quality evidence.
The results of a large UK trial (INTERVAL) did not support such frequent dental appointments.
It found that 30% of people at low risk of oral disease were able to get one every two years without harm to their oral health. Over a four-year period, more frequent screenings had no added benefit. The research concluded that a screening interval based on each person’s individual risk of oral disease did not adversely affect their oral health. This approach was acceptable to patients and dentists and could save money.
Which is the subject;
Regular NHS dental checks include a clinical examination, oral health monitoring and advice. Regular checkups aim to detect the early signs of dental disease, such as tooth decay and gum disease.
NICE guidelines recommend that dentists and patients agree an appropriate interval between examinations. This interval ranges from every three months to every two years for adults. Most dentists encourage people to have a checkup every six months. But these recommendations and customs are based on low-quality evidence.
There is a growing need to reform dental services and prioritize the prevention of oral health problems. The risk of developing oral disease varies among individuals, and therefore resources should be targeted to those at higher risk. COVID-19 has prevented many from accessing dental care and has made these needs more urgent. In work conducted before the pandemic, researchers sought to update the evidence behind current guidelines. They wanted to determine the checkup interval that would best maintain oral health while offering value for money.
What’s new?
The four-year INTERVAL trial was a randomized controlled trial. It involved 2,372 adults from dental practices across the UK. About 70% completed all aspects of the trial and attended the follow-up appointment four years later.
Participants were randomly assigned to one of three groups:
- fixed checks every six months (high and low risk participants)
- screening intervals based on each individual’s risk of oral disease (high and low risk participants)
- regular checkups every two years (only for participants deemed low risk by their dentist);
Oral health was determined in this study by measuring the extent to which the gums bled on probing. This indicates inflammation and early gum disease. The researchers also looked at the extent of tooth decay, tartar build-up, the need for preventive treatment (such as removing plaque and tartar), the need for intervention (such as filling cavities), and dentists’ attitudes toward recall intervals. They asked patients to describe their stress, satisfaction with care, oral health knowledge, attitudes, and behaviors.
Results suggest no dental health benefits from 6-monthly check-ups compared to risk-based intervals or 2-yearly check-ups (for low-risk individuals). There was no difference in gingival bleeding or oral health-related quality of life. Nor did the data show differences in other clinical outcomes.
Overall, participants were satisfied with the dental services they received and were not concerned about their dental health. They had a good knowledge of how to brush, although few participants knew how to spit without rinsing after brushing.
The research included an analysis of costs to the NHS and to patients, and explored people’s willingness to pay for dental appointments. Three different analyzes examined the treatment interval that offered the best value for money while maximizing overall health-related quality of life, overall benefit to society, and dental health benefits.
The results of the economic evaluations were mixed. Benefits for general health were uncertain, possibly because the measure used may not have been sensitive enough to detect differences in dental health. However, for both general and dental health, the 2-year recall period (for low-risk patients) is likely to be the most cost-effective approach due to potential cost savings from fewer appointments.
As far as society was concerned, there were benefits to semi-annual checks because most people valued and were happy to pay for them.
The researchers conclude that a risk-based interval individualized for each individual could save money without having a negative impact on oral health.
Why is it important?
The findings suggest that the practice of six-monthly exams, regardless of a person’s risk of developing dental disease, does not improve oral health.
The results of this study can inform clinical guidelines to help make decisions about the frequency of checkups by dentists. An individualized frequency of screening, based on individual risk, could be a more efficient use of NHS resources.
The results of this study are reflected in the updated Cochrane review, Recall intervals for oral health in primary care patients.
What’s next?
Evidence from this study and the related Cochrane review could be incorporated into clinical guidance for dentists. Moving towards a personalized, variable recall strategy will require close collaboration between policy makers, clinicians and patients.
People valued exams every six months in this study and said they were willing to pay for them. However, the economic analyzes were based on surveys of regular attendees who may value frequent checkups more than other people. The researchers say they need more information about why the checks are so valued — perhaps because they’re an established routine, a recommendation or other reasons. They say careful messaging can help people understand that individualized, risk-based intervals between appointments are safe.
The researchers would like to develop risk assessment tools to help dentists choose recall intervals based on their patients’ likelihood of developing dental disease.
This study included only adults. More research is needed before any change is made to withdraw intervals for younger people.
You may be interested to read
The full paper: Clarkson JE and others. Risk-based adult dental screening at 6-month and 24-month follow-ups: the three-arm INTERVAL RCT. Health Technology Assessment. 2020? 24
Clinical outcome results are summarized here: Clarkson JE et al. Examining the effectiveness of different dental recall strategies in maintaining optimal oral health: the INTERVAL dental recall randomized controlled trial. Br Dent J. 2021? 230:236-243
The protocol for this trial as described in another paper: Clarkson JE et al. INTERVAL (Investigation of NICE Technologies for Enabling Risk-Variable-Adjusted-Length) dental recall trial: a multicentre randomized controlled trial investigating the best dental recall interval for optimal, cost-effective oral health maintenance in edentulous adults in primary care. BMC Oral Health 2018? 18:135
The recent Cochrane Database Systematic Review, which included the results of this study, also concluded that there was little or no difference in caries, gum disease and well-being between 6-month and risk-based examinations in adults: PA reward and others. Recall intervals for oral health in primary care patients. Cochrane Database Syst Rev. 2020? 10: CD004346
Financing: This research was funded by the NIHR Health Technology Assessment programme.
Conflict of interests: One author has received fees from toothpaste manufacturers.
Denial of responsibility: The NIHR evidence summaries are not a substitute for professional medical advice. They provide information about research funded or supported by the NIHR. Please note that the views expressed are those of the author or reviewers and not necessarily those of the NHS, NIHR or the Department of Health and Social Care.
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