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Comparing how patients value and respond to information on risk given in three different forms during dental check-ups: The PREFER randomised controlled trial

Lookup NU author(s): Professor Chris VernazzaORCiD, Professor Laura Ternent



This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).


© 2020 The Author(s). Background: This study aims to compare patient preference for, and subsequent change in, oral health behaviour for three forms of risk information given at dental check-ups (verbal advice compared to verbal advice accompanied by a traffic light (TL) risk card; or compared to verbal advice with a quantitative light fluorescence (QLF) photograph of the patient's mouth). Methods: A multi-centre, parallel-group, patient-randomised clinical trial was undertaken between August 2015 and September 2016. Computer-generated random numbers using block stratification allocated patients to three arms. The setting was four English NHS dental practices. Participants were 412 dentate adults at medium/high risk of poor oral health. Patients rated preference and willingness to pay (WTP) for the three types of information. The primary outcome was WTP. After receiving their check-up, patients received the type of information according to their group allocation. Follow-up was by telephone/e-mail at 6 and 12 months. Mean and median WTP for the three arms were compared using Wilcoxon signed-rank tests. Tobit regression models were used to investigate factors affecting WTP and preference for information type. Secondary outcomes included self-rated oral health and change in oral health behaviours (tooth-brushing, sugar consumption and smoking) and were investigated using multivariate generalised linear mixed models. Results: A total of 412 patients were randomised (138 to verbal, 134 to TL and 140 to QLF); 391 revisited their WTP scores after the check-up (23 withdrew). Follow-up data were obtained for 185 (46%) participants at 6 months and 153 (38%) participants at 12 months. Verbal advice was the first preference for 51% (209 participants), QLF for 35% (145 participants) and TL for 14% (58 participants). TL information was valued lower than either verbal or QLF information (p < 0.0001). Practice attended was predictive of verbal as first preference, and being older. Practice attended, preferring TL the most and having fewer than 20 teeth were associated with increased WTP; and living in a relatively deprived area or having low literacy decreased WTP. There were no significant differences in behaviour change on follow-up. Conclusions: Although a new NHS dental contract based on TL risk stratification is being tested, patients prefer the usual verbal advice. There was also a practice effect which will needs to be considered for successful implementation of this government policy. Trial registration: ISRCTN, ISRCTN71242343. Retrospectively registered on 27 March 2018.

Publication metadata

Author(s): Harris R, Lowers V, Laverty L, Vernazza C, Burnside G, Brown S, Ternent L

Publication type: Article

Publication status: Published

Journal: Trials

Year: 2020

Volume: 21

Online publication date: 06/01/2020

Acceptance date: 22/10/2019

Date deposited: 20/01/2020

ISSN (electronic): 1745-6215

Publisher: BioMed Central Ltd


DOI: 10.1186/s13063-019-3824-3

PubMed id: 31907022


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