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Improving the Quality of Dentistry (IQuaD)


Periodontal disease is the most common oral disease affecting adults. Effective self-care (tooth brushing and interdental aids) for plaque control and removal of risk factors such as calculus, by periodontal instrumentation (PI), commonly known as a “scale and polish”, are considered necessary to prevent and treat periodontal disease.

A Cochrane review found evidence that psychological interventions resulted in improvements in oral hygiene behaviours but there is a lack of reliable evidence to inform clinicians of the relative effectiveness of different types of Oral Hygiene Advice (OHA) on the prevention of periodontal disease in adults. Similarly there is mixed evidence on the effectiveness and optimal frequency of PI. The majority of trials that have been carried out to date have been of poor to moderate quality with few conducted in primary care and a lack of patient centred outcomes and economic analyses reported.

SDPBRN supports, and is a partner in, the NIHR HTA funded IQuaD study (project number 09/01/45). The aim of this study is to compare the effectiveness and cost-effectiveness of theoretically based, personalised oral hygiene advice (OHA) or periodontal instrumentation (PI) at different time intervals or their combination, for improving periodontal health in dentate adults attending general dental practice.

The primary objectives are to test the effectiveness and cost effectiveness of the following dental management strategies:

  1. Personalised OHA versus routine OHA
  2. 12 monthly PI versus 6 monthly PI
  3. No PI versus 6 monthly PI

The research will be carried out in 63 general dental practices in the UK and a total of 1877 participants will be recruited to the trial.

Outcome measures are:

  • Gingival inflammation/bleeding on probing at the gingival margin at 3 year follow-up;
  • Oral hygiene self-efficacy at 3 year follow-up: Oral Health Impact Profile-14 (OHIP-14);
  • Net benefits (mean willingness to pay minus mean costs).

Current status

Recruitment is closed. Intervention phase and data collection ongoing.


Clarkson, J.E. et al., 2013. ‘IQuaD dental trial; improving the quality of dentistry: a multicentre randomised controlled trial comparing oral hygiene advice and periodontal instrumentation for the prevention and management of periodontal disease in dentate adults attending dental primary care.’ BMC Oral Health, 13 (1). 58.

Joint chief investigators

Further details of IQuaD are available on the University of Dundee, Dental Health Services Research Unit website.

Partner programmes