The Role of Supragingival Dental Plaque in the Initiation of Gingivitis

The periodontium, which is responsible for the retention of teeth in the maxilla and mandible, consists of four tissue types. Cementum and alveolar bone are the hard tissues to which the fibrous periodontal ligament anchors the tooth into the skeleton, and the gingiva is the covering tissue of the periodontium (Fig. 42.1). The gingiva is a unique body tissue in that it allows the penetration of calcified tissue (i.e., teeth) into an intact mucosa while protecting the underlying periodontal tissues. The accumulation of microorganisms on the tooth surface along the gingival margin can alter the structure and function of the gingiva, inducing an oral inflammatory reaction. Its clinical expression is called gingivitis. During adolescence gingivitis is almost universal, and in adulthood it affects approximately 50% of the population. Because of the frequent appearance of gingivitis, this disease remains a principal concern for the dentist, since it can convert to other more destructive forms of periodontal disease. Hence, the prevention or cure of gingivitis is of particular interest. The most common method of eliminating gingivitis is by the mechanical removal of the microorganisms found in dental plaque via toothbrush and floss. However, effective mechanical removal of plaque is a tedious, time-consuming process that is affected by an individual’s gingival architecture, tooth position, dexterity, and motivation. Consequently, incomplete removal of dental plaque by mechanical means allows for the induction, continued progression, or both of gingivitis. Therefore, pharmacological agents that prevent or reduce plaque can aid the dentist by effectively preventing or eliminating gingival inflammation. Accordingly, the development of safe and effective topical liquid antimicrobial agents will help in the maintenance of healthy gingival tissues. This chapter examines the relationship of supragingival dental plaque to gingivitis and the unique pharmacokinetic characteristics of common antiplaque agents.