This work aims to introduce dental hygienists to the theory required to practice their skills, educate their patients and the public and to answer questions put to them about dental health. In addition to the revisions incorporated into this edition, there is a new chapter on local anaesthesia which is intended to prepare the reader for the advent of changes which are to be introduced shortly in the UK concerning the regulations governing the practice of dental hygiene. Emphasis is also placed in this edition on the necessity for preventing cross-infection in dental practice.