EFFECTS OF ANTIBIOTIC-TREATMENT ON CLINICAL CONDITIONS AND BACTERIAL-GROWTH WITH GUIDED TISSUE REGENERATION

MUCOGINGIVAL FLAPS WERE REFLECTED over pairs of mandibular molar teeth with Class II furcation invasions. The dimensions of the furcations w ere measured. The teeth were debrided and an expanded polytetrafluoroe thylene (e-PTFE) membrane was placed and retained over one furcation o f each pair (test site) for 4 weeks. The second site served as a contr ol. Eight patients (group 1) with 12 e-PTFE sites received no antibiot ic. Seven patients (group 2) with 12 e-PTFE sites were administered am oxicillin/clavulanate potassium for 10 days. Paper-points were used to collect bacterial samples and clinical indices were recorded at basel ine and weekly for 4 weeks. Paper-point samples and the e-PTFE collect ed at week 4 were sonicated and analyzed by DNA probes for seven putat ive pathogens. At baseline no parameter showed statistical differences between groups or sites. At week 1 significantly greater levels of Pr evotella intermedia type I (P <0.05) and Fusobacterium nucleatum (P <0 .01) were found in group 1. At week 4, paper-point samples from test s ites (P <0.05) and e-PTFE materials (P <0.001) showed significantly hi gher presence of Bacteroides forsythus in group 1. No significant micr obial changes were found for control sites over time or between groups . The total bacterial load at test sites over time increased similarly for patients administered or not administered the antibiotic. Clinica l signs of inflammation were significantly greater in group 1 and asso ciated with the presence of B. forsythus (P <0.01).