The microbiota of periodontal pockets with different depths in therapy-resistant periodontitis

This study presents the composition of the cultivable microbiota colonising periodontal pockets of different depths among 2 patient-groups classified as non-responsive (NR-group; 11 participants) or responsive (R-group; 10 pa rticipants) to periodontal treatment. Microbiological samples from three ty pes of pocket (<4 mm deep A-samples; 4-5 mm B-samples; >5 mm C-samples) wer e analysed by cultural methods for putative periodontitis pathogens, microb ial groups constituting greater than or equal to 5% of the total cultivable flora and opportunistic pathogens. Actinomyces naeslundii, A. israelii, Ba cteroides forsythus, Fusobacterium spp, Porphyromonas gingivalis, Prevotell a intermedia, Peptostreptococcus micros, anaerobic streptococci and faculta tive anaerobic streptococci were most prevalent. Actinobacillus actinomycet emcomitans, Staphylococcus aureus, enteric rods and yeasts were less preval ent, The periodontitis pathogens Bacteroides forsythus, Fusobacterium spp, Porphyromonas gingivalis, Prevotella intermedia and Peptostreptococcus micr os constituted together (on average) less than or equal to 23% of the viabl e counts in the A- and B-samples of both patient groups and in the C-sample s of the R-group. In the C-samples of the NR-group their mean counts were 4 5%. Correlations were found between smoking habits and the five pathogens i n the C-samples and in pooled pocket depth samples. The results show that g roups of periodontopathogens should be considered a causal factor in therap y-resistant periodontitis. Further, smoking and deep pockets can enhance a shift in the balance of the subgingival microflora predisposing a site to d isease and a susceptible host may be the pre-requisite to therapy-resistant periodontitis.