The delivery of oral hygiene advice is a crucial component of the management of patients susceptible to periodontal disease. However, the complexity of the issues surrounding such advice is frequently underestimated. It is not simply a question of manual dexterity; many factors influence compliance and motivation, including lifestyle, beliefs, attitude and understanding, and such factors need to be taken into account in order to effect permanent change in a patient's habits. This article reviews these issues and examines oral hygiene techniques and methods of assessment.