Clinical research in implant dentistry: study design, reporting and outcome measurements: consensus report of Working Group 2 of the VIII European Workshop on Periodontology

Aims: The objective of this working group was to assess and make specific recommendations to improve the quality of reporting of clinical research in implant dentistry and discuss ways to reach a consensus on choice of outcomes.

Material and methods: Discussions were informed by three systematic reviews on quality of reporting of observational studies (case series, case-control and cohort) and experimental research (randomized clinical trials). An additional systematic review provided information on choice of outcomes and analytical methods. In addition, an open survey among all workshop participants was utilized to capture a consensus view on the limits of currently used survival and success-based outcomes as well as to identify domains that need to be captured by future outcome systems.

Results: The Workshop attempted to clarify the characteristics and the value in dental implant research of different study designs. In most areas, measurable quality improvements over time were identified. The Workshop recognized important aspects that require continued attention by clinical researchers, funding agencies and peer reviewers to decrease potential bias. With regard to choice of outcomes, the limitations of currently used systems were recognized. Three broad outcome domains that need to be captured by future research were identified: (i) patient reported outcome measures, (ii) peri-implant tissue health and (iii) performance of implant supported restorations. Peri-implant tissue health can be measured by marginal bone level changes and soft tissue inflammation and can be incorporated in time to event analyses.

Conclusions: The Workshop recommended that collaboration between clinicians and epidemiologists/clinical trials specialists should be encouraged. Aspects of design aimed at limitation of potential bias should receive attention by clinical researchers, funding agencies and journal editors. Adherence to appropriate reporting guidelines such as STROBE and CONSORT are necessary standards. Research on outcome measure domains is an area of top priority and should urgently inform a proper process leading to a consensus on outcome measures in dental implant research.