Year : 2017

Volume : Volume 7

Issue : Issue 3

Address for correspondence :
Dr. B. Harish Reddy.
hariesh_reddy@yahoo.com

Abstract

Background: The primary aim of this review was to assess effects of placebo interventions in periodontal clinical trials. The study also sought to examine whether trials have included special strategies to identify placebo responders and differences in outcomes between placebo and control groups. Materials and Methods: The MEDLINE bibliographic database and the PubMed Central (PMC) digital repository were searched for English language articles. Assessment of study quality focused on two key domains; results attributable to Hawthorne effect or placebo effect and study design options to identify placebo responders and to lower the placebo effect. Allocation to comparison groups, instances of auxiliary care apart from treatments under evaluation, assessment of outcomes were also assessed.
Results: The MEDLINE search yielded 6 articles and the PMC search yielded 16 articles. Additional 2 articles were found from references from the above articles. In many trials, the terms ‘placebo effects” and ‘Hawthorne effect” were used without distinction on whether the clinical improvement in a group of patients is attributable to the fact of being under study or because of the belief in the material being used. In periodontics, there are a paucity of trials which have effectively filtered out the “placebo responders” i.e. subjects in which the clinical evidence is overshadowed by the placebo effect. Conclusion: The terminology used to describe the placebo effect or Hawthorne effect is inconsistent and is a matter of intensive debate. The biggest grey area for a researcher or an author is the lack of standard guidelines towards using terms such as placebo and Hawthorne effect. Even after recognizing these effects, there is clearly a paucity in tools predicting the degree and effects of these responses.
Keywords: Hawthorne effect, placebo, periodontal disease.