Methodological issues in oral health research: intervention studies.

To provide a broad overview of methodological issues in the design and evaluation of intervention studies in dental public health, with particular emphasis on explanatory trials, pragmatic trials and complex interventions. We present a narrative summary of selected publications from the literature outlining both historical and recent challenges in the design and evaluation of intervention studies and describe some recent tools that may help researchers to address these challenges. It is now recognised that few intervention studies in dental public health are purely explanatory or pragmatic. We describe the PRECIS tool which can be used by trialists to assess and display the position of their trial on a continuum between the extremes of explanatory and pragmatic trials. The tool aims to help trialists make design decisions that are in line with their stated aims. The increasingly complex nature of dental public health interventions presents particular design and evaluation challenges. The revised Medical Research Council (MRC) guidance for the development and evaluation of complex interventions which emphasises the importance of planning and process evaluation is a welcome development. We briefly describe the MRC guidance and outline some examples of complex interventions in the field of oral health. The role of observational studies in monitoring public health interventions when the conduct of RCTs is not appropriate or feasible is acknowledged. We describe the STROBE statement and outline the implications of the STROBE guidelines for dental public health. The methodological challenges in the design, conduct and reporting of intervention studies in oral health are considerable. The need to provide reliable evidence to support innovative new strategies in oral health policy is a major impetus in these fields. No doubt the 'Methodological Issues in Oral Health Research' group will have further opportunities to highlight this work. © 2012 John Wiley & Sons A/S.