[Antimicrobial approaches to periodontal therapy].

The relationship between the periodontal microbiota and the threshold for periodontal disease is dependent on the specific bacterial composition of the plaque and the resistance of the host. Supragingival plaque is the cause of gingivitis and plays a primary role in the initiation of periodontitis. The 0.2% chlorhexidine mouthwash (twice a day) is safe and most effective antiplaque and anti-gingivitis agent. The use of adjunctive tetracycline for 2 week periods (1 gm daily) with root debridement is highly effective against Actinobacillus actinomycetemcomitans and many of suspected virulence microorganisms, the major etiological agents of juvenile periodontitis. For rapidly progressive periodontitis and refractory adult periodontitis, metronidazole for 1-2 week periods (600 mg.daily) has excellent activity against strictly anaerobic bacteria such as Bacteroides gingivalis, Spirochetes and others. Clinical use of antimicrobial agent in adjuvant with scaling, root planing, and personal oral hygiene instruction cause a significant improvement of the periodontium.