The focus of this study is, in a sample of patients in private dental clinics, to assess the perception of the efficacy of described therapies and procedures, based on the research evidence presented. Patients will be presented with information about the effectiveness of the therapy in a plain language summary. The independent variable in a research is the type of research on which the evidence is based (randomized controlled trial or cross sectional study-survey) and the number of the participants in a study (small vs big sample), resulting in total 4 combinations of research type presented, on which participants can rely to decide about the effectiveness of the therapy. Each participant will be presented with only one combination when reading two plain language summaries, randomly assigned.