On a regular basis, dental practitioners have to make decisions regarding their care of their patients. Previously, dentists did this almost instinctively, drawing upon personal resources such as clinical experience, training, colleagues’ opinions, social media and past successes…and failures. Today it is expected that good clinical practice be based on the best and most currently available evidence, obtained by critical appraisal of scientific research and literature, books, journals, internet publications, and participation at continuous education programmes. This has led to an explosion in research, not all of which is scientifically sound or ethically acceptable. Evidence based dentistry (EBD) evolved as a means of evaluating the science and rigour of research (the focus of the next chapter in this series), while numerous codes of conduct have been developed to try to ensure ethical standards.