Principles of aetiology and pathogenesis governing the treatment of periodontal disease.

Modern periodontal therapy is based on the fundamental realization that accumulation of bacterial plaque at the gingival margin causes the incipient lesion in periodontal disease. Without interference, most lesions will progress to involve deeper parts of the periodontium. Recent research has revealed that dental plaque comprises a multitude of bacteria in various combinations with a variety of pathogenic potentials, that supragingival plaque is significantly different from the subgingival variety and that particular bacterial species are associated with different periodontal disease states. However, studies have not yet clearly defined a group of bacteria, much less one species, that is responsible for the different forms of periodontal disease. Therefore, the concept of specific pathogenesis is still not ready for clinical application in the prevention and treatment of these diseases, and dental plaque must be dealt with as an entity. Investigators have failed to demonstrate local or systemic factors, other than local aggregates of micro-organisms, that cause gingivitis and periodontitis. As in any other infections, the pathological events and final outcome are determined by the relationship between the microflora and host resistance. Presently, there are no known means by which the host factors can be manipulated to enhance the defense of the periodontium. Therefore, the only rationale for the clinical management of periodontal diseases is to interfere with the microbiological events. Since it is known that gingivitis precedes periodontitis, the only useful approach to preventing the development of periodontitis is to control gingivitis. The treatment of moderate and severe periodontitis also focuses on the elimination of subgingival bacteria and inhibition of recolonization. The target for this is the root surface, which must be detoxified. Surgical elimination of periodontal pockets is still a valid approach to the treatment of the advanced periodontal lesion but only in so far as it provides access to the subgingival accumulations of plaque. The key to success in periodontal therapy is to prepare the tooth surfaces in such a way as to make them biologically acceptable to the gingival tissues. This may be achieved with or without gaining surgical access.