Evaluation of acrylic strips containing amoxycillin with clavulanic acid for local drug delivery.

The in vitro release of amoxycillin with clavulanic acid from acrylic strips at initial concentrations of 30, 40 and 50 per cent w/w was monitored using a double-beam ultraviolet spectrophotometer and compared with release of tetracycline hydrochloride. Highest levels of the antibacterial agents were released during the first 24 h period. Therapeutic levels of the drugs continued to be released during the subsequent 9 day period and were shown to be biologically active. Furthermore, for amoxycillin with clavulanic acid, an initial concentration of 40 per cent gave the highest level of release on day 10; while, for tetracycline, 50 per cent provided the highest level of release. Local application of 40 per cent amoxycillin with clavulanic acid incorporated into acrylic strips placed in periodontal pockets in patients with established periodontitis produced a marked change in the subgingival microflora as monitored by dark-field microscopy and cultural techniques. These changes in the subgingival flora were concomitant with elimination of bleeding on probing at the treated sites and were still evident 3 weeks after removal of the acrylic strips. The sensitivity of Bacteroides gingivalis (syn. Porphyromonas gingivalis) and Bacteroides intermedius (syn. Prevotella intermedia) isolated before and after treatment to amoxycillin with clavulanic acid remained unchanged.

Amoxycillin with clavulanic acid and tetracycline in periodontal therapy.

The effects of tetracycline and amoxycillin with clavulanic acid on the clinical parameters and subgingival flora of eight patients with rapidly progressive periodontitis was assessed. Subjects received either tetracycline 250 mg four times daily or amoxycillin 250 mg with clavulanic acid 125 mg three times daily for a period of 2 weeks together with subgingival scaling and root planning. Both treatment regimens produced significant reductions in bleeding on probing and probing pocket depths which were still present 16 weeks after the antibiotic therapy. A significant reduction in the mean percentage of black-pigmented Bacteroides spp., Fusobacterium nucleatum and anaerobic corroding bacilli was also obtained. Both treatment regimens were equally effective in reducing the clinical parameter and altering the subgingival flora. The MIC values for Bacteroides gingivalis (Porphyromonas gingivalis). Bacteroides intermedius (Prevotella intermedia) and F. nucleatum to amoxycillin with clavulanic acid remained constant throughout the period of investigation. The MIC values of these organisms to tetracycline increased.

Identification, and susceptibility to seven antimicrobial agents, of 61 gram-negative anaerobic rods from periodontal pockets.

Sixty-one cultures of Gram-negative anaerobic rods were isolated from deep periodontal pockets of patients with rapidly progressive periodontitis. Isolates were speciated as Bacteroides gingivalis (18 isolates), Bacteroides intermedius (8), Bacteroides oris (1), Bacteroides gracilis (17) and Fusobacterium nucleatum (17). Their susceptibilities, to seven antimicrobial agents, were determined in vitro using a plate dilution technique. Amoxycillin and amoxycillin with clavulanic acid were active against all isolates (MIC less than 1 mg/l) and proved the most effective agents tested. F. nucleatum and B. gracilis showed resistance to erythromycin; F. nucleatum had MIC values ranging from 0.03 mg/l up to 128 mg/l when tested with this, least effective agent. Metronidazole was effective against all isolates except for a few strains of B. gracilis (MIC less than 4 mg/l). Tetracycline hydrochloride and minocycline were active against all isolates except for a few strains of B. gracilis (MIC less than 2 mg/l with both minocycline and tetracycline hydrochloride). Penicillin proved less effective than amoxycillin with regard to inhibition of B. gracilis.