Abstract
In periodontal treatment the importance of self-performed plaque control is frequently acknowledged but often underestimated. This article reviews the evidence relating to the effects of good oral hygiene on both the initiation and progression of gingivitis and periodontitis, and on treatment outcomes. Recent evidence suggests that an optimal level of supragingival plaque control can have profound effects on the subgingival microflora and this, together with evidence indicating that root surface microbial contaminants are superficially located within the biofilm, has significant therapeutic implications.