Oral microflora of supragingival and subgingival biofilms in Algerian healthy adults

The purpose of this investigation was to define the cultivable oral microflora in supragingival and subgingival plaques of Algerian healthy adults. Supragingival and subgingival plaque samples were collected from 65 Algerian caries-free, periodontally healthy subjects. Samples were taken from approximal surfaces and analysed for bacterial content after being inoculated on non-selective and selective media and incubated under different atmospheres; aerobic, capnophilic and anaerobic. The standard identification procedures by biochemical tests were used. Pearson’s Chi-square χ2 test (P < 0.05, χ2-test) was used to assess the differences between the isolation frequencies. Gram negative anaerobic rods (Porphyromonas assacharolytica, Porphyromonas gingivalis, Prevotella melaninogenica, Prevotella intermedia, Prevotella buccae, Fusobacterium mortiferum, Bacteroides ureolyticus, Bacteroides ovatus, Bacteroides eggertii, Capnocytophaga sp. and Aggregatibacter actinomycetemcomitans) more often were detected in subgingival plaque than supragingival plaque (p<0.05, χ2-test). However, streptococci and Actinomyces naeslundii were isolated more frequently from supragingival plaque. (p<0.05, χ2-test). Facultative anaerobic Gram positive cocci were also isolated both from supragingival and subgingival plaques in comparable proportions (P>0.05, χ2-test) with the predominance of enterococci which were isolated even from supragingival and subgingival plaques in considerable proportions. The supragingival bacterial flora in healthy adults was composed mainly of Gram positive cocci and anaerobic Gram positive rods with the predominance of Streptococci and Actinomyces naeslundii, respectively; whereas, anaerobic Gram negative rods and facultative anaerobic Gram positive cocci were the predominant bacteria in subgingival plaque.