The INTERVAL trial, funded by NIHR HTA, was a UK multi-centre randomised controlled trial evaluating the effectiveness and cost effectiveness of three dental recall strategies, including one advocated by the recent NICE guidance, on maintaining oral health.
An NIHR-HTA funded feasibility phase started in June 2009 and recruited across 10 dental practices in the UK. After the initial 18 month feasibility study, the trial continued to full recruitment of 2372 participants across 50 dental practices.
The primary outcome is the mean proportion of site bleeding on probing at 4 years follow-up.
INTERVAL participants were adults with healthy gums that attended the dentist regularly. Dentists in INTERVAL were asked to stratify their patients into patients that could go without a dental check-up for a maximum of 24 months and those who couldn’t. The trial showed that there was no evidence of a difference in bleeding gums (primary outcome) between different frequencies of dental check-ups (no check-up, 6-monthly, or risk-based over 4 years) for both subgroups. The results of the study have been published in the British Dental Journal: https://www.nature.com/articles/s41415-021-2612-0
The INTERVAL trial was led jointly by Professor Jan Clarkson and Professor Nigel Pitts from the University of Dundee.
- Craig Ramsay; firstname.lastname@example.org
Jan E. Clarkson, Nigel B. Pitts, Debbie Bonetti, Dwayne Boyers, Hazel Braid, Robert Elford, Patrick A. Fee, Ruth Floate, Beatriz Goulão, Gerry Humphris, Ian Needleman, John D. T. Norrie, Fiona Ord, Marjon van der Pol, Craig R. Ramsay, David N. J. Ricketts, Helen V. Worthington, Linda Young and INTERVAL Trial Collaboration. INTERVAL (investigation of NICE technologies for enabling risk-variable-adjusted-length) dental recalls trial: a multicentre randomised controlled trial investigating the best dental recall interval for optimum, cost-effective maintenance of oral health in dentate adults attending dental primary care. BMC Oral Health 2018, 18:135 https://bmcoralhealth.biomedcentral.com/articles/10.1186/s12903-018-0587-2
Clarkson JE, Pitts NB, Goulao B, Boyers D, Ramsay CR, Floate R, Braid HJ, Fee PA, Ord FS, Worthington HV, van der Pol M, Young L, Freeman R, Gouick J, Humphris GM, Mitchell FE, McDonald AM, Norrie JD, Sim K, Douglas G, Ricketts D. Risk-based, 6-monthly and 24-monthly dental check-ups for adults: the INTERVAL three-arm RCT. Health Technol Assess. 2020 Nov;24(60):1-138. doi: 10.3310/hta24600. PMID: 33215986; PMCID: PMC7701991.
Clarkson JE, Pitts NB, Fee PA, Goulao B, Boyers D, Ramsay CR, Floate R, Braid HJ, Ord FS, Worthington HV, van der Pol M, Young L, Freeman R, Gouick J, Humphris GM, Mitchell FE, McDonald AM, Norrie JD, Sim K, Douglas G, Ricketts D Examining the effectiveness of different dental recall strategies on maintenance of optimum oral health: the INTERVAL dental recalls randomised controlled trial. Br Dent J 230, 236–243 (2021). https://doi.org/10.1038/s41415-021-2612-0