Examining the impact of oral hygiene advice and/or scale and polish on periodontal disease: the IQuaD cluster factorial randomised controlled trial

Jan Clarkson* (Corresponding Author), Craig Ramsay, Thomas Lamont, Beatriz Goulao, Helen Worthington, Peter Heasman, John Norrie, Dwayne Boyers, Anne Duncan, Marjon van der Pol, Linda Young, Lorna Macpherson, Giles McCracken

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)


Objective To compare the clinical effectiveness and cost benefit of different frequencies of scale and polish (S&P) treatments in combination with different types of oral hygiene advice (OHA).Design Multi-centre, multi-level cluster randomised factorial open trial with blinded outcome evaluation. UK dental practices were cluster randomised to deliver OHA as usual or personalised. In a separate randomisation, patients were allocated to receive S&P 6-monthly, 12-monthly or never.Setting UK primary dental care.Participants Practices providing NHS care and adults who had received regular dental check-ups.Main outcome measures The percent of sites with bleeding on probing, patient confidence in self-care, incremental net benefits (INB) over three years.Results Sixty-three practices and 1,877 adult patients were randomised and 1,327 analysed (clinical outcome). There was no statistically significant or clinically important difference in gingival bleeding between the three S&P groups (for example, six-monthly versus none: difference 0.87% sites, 95% CI: 1.6 to 3.3, p = 0.48) or between personalised or usual OHA groups (difference -2.5% sites, -95%CI: -8.3 to 3.3, p = 0.39), or oral hygiene self-efficacy (cognitive impact) between either group (for example, six-monthly versus none: difference -0.028, 95% CI -0.119 to 0.063, p = 0.543). The general population place a high value on, and are willing to pay for, S&P services. However, from a dental health perspective, none of the interventions were cost-effective.Conclusion Results suggest S&P treatments and delivering brief personalised OHA provide no clinical benefit and are therefore an inefficient approach to improving dental health (38% of sites were bleeding whatever intervention was received). However, the general population value both interventions.
Original languageEnglish
Pages (from-to)229-235
Number of pages7
JournalBritish Dental Journal
Issue number4
Early online date26 Feb 2021
Publication statusPublished - Feb 2021

Bibliographical note

We would like to acknowledge the participating dental practice teams and patients without whose valuable contribution this study could not have taken place. We would also like to acknowledge the role of the IQuaD Group members from the NIHR HTA IQuaD final report for their dedication and support. In addition, we would like to thank the IQuaD Perio-Advisory Committee members for their support throughout the trial; Mary Cullinan, Mark Ide, Ian Needleman, Tim Newton, Greg Seymour. Ethical approval: a favourable ethical opinion for the trial was provided by the East of Scotland Research Ethics 24 March 2011 (REC reference number 10/S0501/65).

Funding information

This project was funded by the NIHR HTA Programme (project number 09/01/45) and was published in full in Health Technology Assessment 2018: 22(38) Current Controlled Trials number ISRCTN56465715: https://doi.org/10.3310/hta22380. The results have been reproduced as per the non-commercial Government licence: http://www.nationalarchives.gov.uk/doc/non-commercial-government-licence/version/2/. Further information available at: https://www.journalslibrary.nihr.ac.uk/HTA. The Health Services Research Unit and the Health Economics Research Unit are funded by the Chief Scientist Office of the Scottish Government Health and Social Care Directorates. This report presents independent research commissioned by the National Institute for Health Research (NIHR). The views and opinions expressed by authors in this publication are those of the authors and do not necessarily reflect those of the NHS, the NIHR, MRC, CCF, NETSCC, the NIHR HTA programme or the Department of Health.


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