Effect of systemic use of amoxicillin and metronidazole during mechanical therapy on the periodontal microorganisms in subgingival plaque and saliva of patients with aggressive periodontitis

Abstract

Objective: To explore the effect of systemic use of amoxicillin and metronidazole during mechanical therapy on the clinical parameters of the first molars and periodontal microorganisms in subgingival plaque and saliva in patients with generalized aggressive periodontitis (GAgP). Methods: A total of 23 GAgP patients were recruited from Peking University School and Hospital of Stomatology from January 2006 to December 2009 and then randomly divided into two groups according to random number table: 12 patients received scaling and root planning (SRP) only and 11 patients received SRP combined with systemic administration of antibiotics (amoxicillin and metronidazole for a week after supragingival scaling). Clinical examination of periodontal parameters and collection of saliva and pooled subgingival plaque samples from mesial-buccal sites of 4 first molars were performed before initial therapy and 2, 4 and 6 months respectively after mechanical therapy, and saliva samples were also collected 2 weeks after therapy. Eight different periodontal microorganisms were detected in these samples by PCR. In addition, semiquantitative analysis of red complex microorganisms [Porphyromonas gingivalis (Pg), Tannerella forsythia (Tf), Treponema denticola (Td)] was performed. Results: Both therapies led to significant decrease of the plaque index (PLI), probing depth (PD) and bleeding index (BI) from mesial-buccal sites of first molars. Meanwhile the PD of antibiotics group [(4.21±1.50), (4.00±1.54), (3.84±1.89) mm of 2, 4 and 6 months respectively after therapy] was significantly lower than the SRP group [(5.29±1.27), (5.30±1.34), (4.98±1.36) mm of 2, 4 and 6 months respectively after therapy] at 3 different time points after mechanical therapy (P<0.05). In the antibiotics group, the quantities of Pg, Tf and Td in subgingival plaque samples (the median quantity decreased to 0.0 ng at 2, 4 and 6 months after therapy) and saliva samples (the median quantity of Tf and Td decreased to 0.0 ng at 2, 4 and 6 months after therapy (P<0.05), and the median quantity of Pg decreased to 16.3, 59.6 and 22.4 ng at 2, 4 and 6 months respectively after therapy) significantly decreased at 3 different time points after mechanical therapy compared with before therapy (P<0.05). While in the SRP group, there were no significant changes in the quantities of Tf and Td in saliva at 2, 4 and 6 months after mechanical therapy (P>0.05) , and the quantities of Tf and Td in subgingival plaque significantly decreased only at 2 months after therapy (P<0.05). Conclusions: SRP combined with systemic administration of amoxicillin and metronidazole could achieve greater improvement in PD of first molars and better control of the amounts of red complex microorganisms in the saliva and subgingival plaque of GAgP patients over a 6-month period.