Antibiotics in Periodontal Therapy

Perforation of teeth through the continuous epithelial lining of the oral cavity is a singular anatomical situation. The dental surface consists of hard tissues that lack the potential to renew themselves and to shed their superficial layer. The microecologic system of the oral cavity is colonised by more than 400 different bacterial species (Moore and Moore, 1994). Approximately 150 or more different species may be detected and cultivated from the oral cavity of a single individual. Some bacteria are capable of adhering to and colonising dental surfaces, thereby preparing the ground for the colonisation by other microorganisms. The layer that is generated in this manner is called dental plaque, bacterial plaque, or biofilm. Biofilm is the name of organised aggregations on solid surfaces (e.g. on teeth but also ship bodies, artificial heart valves, water pipes etc.) that consist of microorganisms, extracellular bacterial macromolecules, and products originating from the surrounding medium (e.g. saliva or sulcus fluid). Bacterial plaque is the particular oral form of biofilm. The structure of biofilm not only hinders diffusion of growth factors into bacterial plaque but also forms an effective barrier against host defence (e.g. antibodies, lysozyme, lactoferrine) and antimicrobial substances (e.g. mouth rinses, antibiotics). In contrast to the epithelial surfaces of the body, teeth are not capable of shedding their superficial layers with the adhering microorganisms. Hence, gingivitis and periodontitis are characterised by inflammatory and immune response to the oral microflora, particularly that part that adheres to the tooth surface or has been established subgingivally. The primary etiologic factor of most inflammatory periodontal diseases (plaque-induced gingivitis, chronic and aggressive periodontitis) is bacterial plaque. The removal of supraand subgingival biofilm that is required for therapy of periodontal diseases is accomplished mechanically by profesAntibiotics in Periodontal Therapy