It is possible to preserve or restore oral health and to avoid or treat the two plaque diseases, caries and periodontitis. These two diseases are extremely closely correlated with oral hygiene status. The patient's understanding of oral structures and his or her interest in preserving or restoring healthy teeth and gums depends on instruction and motivation. There is, unfortunately, no scientifically based method of reliably motivating every patient. A person's ability to be motivated is substantially moulded by his social position, intelligence, personality and attitude to his body and health. The techniques and methods illustrated are intended to stimulate and activate appropriate attitudes. A standard of oral hygiene that helps to prevent caries and periodontitis can be achieved only by the dental team in dental practice and not by collective measures.