{"doi":"10.3310/hta24600","title":"Risk-based, 6-monthly and 24-monthly dental check-ups for adults: the INTERVAL three-arm RCT","abstract":"Background Traditionally, patients are encouraged to attend dental recall appointments at regular 6-month intervals, irrespective of their risk of developing dental disease. Stakeholders lack evidence of the relative effectiveness and cost-effectiveness of different recall strategies and the optimal recall interval for maintenance of oral health. Objectives To test effectiveness and assess the cost–benefit of different dental recall intervals over a 4-year period. Design Multicentre, parallel-group, randomised controlled trial with blinded clinical outcome assessment at 4 years and a within-trial cost–benefit analysis. NHS and participant perspective costs were combined with benefits estimated from a general population discrete choice experiment. A two-stratum trial design was used, with participants randomised to the 24-month interval if the recruiting dentist considered them clinically suitable. Participants ineligible for 24-month recall were randomised to a risk-based or 6-month recall interval. Setting UK primary care dental practices. Participants Adult, dentate, NHS patients who had visited their dentist in the previous 2 years. Interventions Participants were randomised to attend for a dental check-up at one of three dental recall intervals: 6-month, risk-based or 24-month recall. Main outcomes Clinical – gingival bleeding on probing; patient – oral health-related quality of life; economic – three analysis frameworks: (1) incremental cost per quality-adjusted life-year gained, (2) incremental net (societal) benefit and (3) incremental net (dental health) benefit. Results A total of 2372 participants were recruited from 51 dental practices; 648 participants were eligible for the 24-month recall stratum and 1724 participants were ineligible. There was no evidence of a significant difference in the mean percentage of sites with gingival bleeding between intervention arms in any comparison. For the eligible for 24-month recall stratum: the 24-month ( n = 138) versus 6-month group ( n = 135) had an adjusted mean difference of –0.91 (95% confidence interval –5.02 to 3.20); the risk-based ( n = 143) versus 6-month group had an adjusted mean difference of –0.98 (95% confidence interval –5.05 to 3.09); the 24-month versus risk-based group had an adjusted mean difference of 0.07 (95% confidence interval –3.99 to 4.12). For the overall sample, the risk-based ( n = 749) versus 6-month ( n = 737) adjusted mean difference was 0.78 (95% confidence interval –1.17 to 2.72). There was no evidence of a difference in oral health-related quality of life between intervention arms in any comparison. For the economic evaluation, under framework 1 (cost per quality-adjusted life-year) the results were highly uncertain, and it was not possible to identify the optimal recall strategy. Under framework 2 (net societal benefit), 6-month recalls were the most efficient strategy with a probability of positive net benefit ranging from 78% to 100% across the eligible and combined strata, with findings driven by the high value placed on more frequent recall services in the discrete choice experiment. Under framework 3 (net dental health benefit), 24-month recalls were the most likely strategy to deliver positive net (dental health) benefit among those eligible for 24-month recall, with a probability of positive net benefit ranging from 65% to 99%. For the combined group, the optimal strategy was less clear. Risk-based recalls were more likely to be the most efficient recall strategy in scenarios where the costing perspective was widened to include participant-incurred costs, and in the Scottish subgroup. Limitations Information regarding factors considered by dentists to inform the risk-based interval and the interaction with patients to determine risk and agree the interval were not collected. Conclusions Over a 4-year period, we found no evidence of a difference in oral health for participants allocated to a 6-month or a risk-based recall interval, no","journal":"Health Technology Assessment","year":2020,"id":96800,"datarank":1.928961603724547,"base_score":3.5553480614894135,"endowment":3.5553480614894135,"self_citation_contribution":0.5333022092234121,"citation_network_contribution":1.3956593945011349,"self_endowment_contribution":0.5333022092234121,"citer_contribution":1.3956593945011349,"corpus_percentile":null,"corpus_rank":null,"citation_count":34,"citer_count":29,"citers_with_citation_signal":20,"citers_with_endowment":20,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.9508,"is_data_producer":true,"deposit_databanks":{"ISRCTN":["ISRCTN95933794"]},"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2020-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":479373,"name":"Nigel Pitts","orcid":"0000-0001-6184-4213","position":1,"is_corresponding":false},{"id":473278,"name":"Beatriz Goulão","orcid":"0000-0003-1490-7183","position":2,"is_corresponding":false},{"id":343724,"name":"Dwayne Boyers","orcid":"0000-0002-9786-8118","position":3,"is_corresponding":false},{"id":80999,"name":"Craig Ramsay","orcid":"0000-0003-4043-7349","position":4,"is_corresponding":false},{"id":479374,"name":"Ruth Floate","orcid":"0000-0003-2424-4643","position":5,"is_corresponding":false},{"id":479375,"name":"Hazel J Braid","orcid":"0000-0002-2062-8546","position":6,"is_corresponding":false},{"id":479376,"name":"Patrick A Fee","orcid":"0000-0002-7188-3416","position":7,"is_corresponding":false},{"id":479377,"name":"Fiona Ord","orcid":"0000-0002-9901-7739","position":8,"is_corresponding":false},{"id":343719,"name":"Helen V Worthington","orcid":"0000-0002-4851-7469","position":9,"is_corresponding":false},{"id":479378,"name":"Marjon van der Pol","orcid":"0000-0003-0636-1184","position":10,"is_corresponding":false},{"id":479379,"name":"Linda Young","orcid":"0000-0002-6004-3374","position":11,"is_corresponding":false},{"id":479380,"name":"Ruth Freeman","orcid":"0000-0002-8733-1253","position":12,"is_corresponding":false},{"id":479381,"name":"Jill Gouick","orcid":"0000-0002-1456-8241","position":13,"is_corresponding":false},{"id":479382,"name":"Gerry Humphris","orcid":"0000-0002-4601-8834","position":14,"is_corresponding":false},{"id":479383,"name":"Fiona E. Mitchell","orcid":"0000-0002-7922-0676","position":15,"is_corresponding":false},{"id":349915,"name":"Alison McDonald","orcid":"0000-0002-0256-2889","position":16,"is_corresponding":false},{"id":349916,"name":"John Norrie","orcid":"0000-0001-9823-9252","position":17,"is_corresponding":false},{"id":479384,"name":"Kirsty Sim","orcid":"0000-0002-2365-5013","position":18,"is_corresponding":false},{"id":479385,"name":"Gail Douglas","orcid":"0000-0002-0531-3909","position":19,"is_corresponding":false},{"id":479386,"name":"David Ricketts","orcid":"0000-0002-9851-1778","position":20,"is_corresponding":false},{"id":479372,"name":"Jan Clarkson","orcid":"0000-0001-5940-2926","position":0,"is_corresponding":true}],"reference_count":120,"raw_metadata":null,"created_at":"2026-07-18T22:35:06.014648Z","pmid":"33215986","pmcid":null,"fwci":null,"citation_percentile":null,"influential_citations":0,"oa_status":null,"license":null,"views":0,"total_file_size_bytes":0,"version_count":0,"fair_f":null,"fair_a":null,"fair_i":null,"fair_r":null,"fair_zscore":null,"fair_rationale":null,"fair_model":null,"fair_agent_version":null,"fair_fulltext_source":null,"fair_has_llm":null,"fair_computed_at":null,"clinical_trials":[],"software_tools":[],"db_accessions":[],"linked_datasets":[],"topics":[]}