OCCURRENCE OF CERTAIN BACTERIAL SPECIES AND MORPHOTYPES IN JUVENILE PERIODONTITIS IN CHILE

THE OCCURRENCE OF Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia, Eikenella corrodens, Fusobacterium nucleatum, Campylobacter rectus, Capnocytophaga species, and certain b acterial morphotypes was determined in 18 affected and 18 unaffected s ites in 10 localized juvenile periodontitis (LJP) patients, and in 10 affected and 10 unaffected sites in 5 generalized juvenile periodontit is (GJP) patients. The subgingival proportion of the 7 bacterial speci es was determined by selective and nonselective culturing. The results showed that when considering the pure prevalence of bacteria (> 0%) t here were significant differences (P < 0.05) in the subgingival plaque microflora of the affected sites versus those of the unaffected sites for P. gingivalis, A. actinomycetemcomitans, P. intermedia, E. corrod ens, C. rectus, and F. nucelatum in LJP, and for P. gingivalis, P. int ermedia, and F. nucleatum in GJP. The mean proportions of cocci, motil e rods and spirochetes were also significantly different (P < 0.05) in affected sites compared to unaffected sites. Capnocytophaga sp, F. nu cleatum, P. intermedia, and E. corrodens were found in more than 75% o f affected sites LJP. When taking the approach that an organism, to be associated with periodontal disease, has to be detected above a certa in minimum threshold, the results indicated that bacteria most frequen tly associated with LJP and GJP in Chile are P. gingivalis (66% of LJP and 80% of GJP affected sites), and A. actinomycetemcomitans (44% of LJP and 50% in GJP affected sites). Different bacterial species may be judged to be important in the disease process depending upon whether a pure bacterial prevalence, or a prevalence above a certain detection level, is considered.