Background: Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, and Prevotella intermedia are the major periodontal bacteria species in most forms of progressive periodontitis in Scandinavia and the United States. The occurrence of periodontal pathogens appears to be different in subjects of different ethnic origin, and geographical factors may influence the distribution of these species.
Methods: The occurrence of A. actinomycetemcomitans, P. gingivalis, and P. intermedia was determined using a DNA probe in progressive adult periodontitis in Chileans. Sixty patients (mean age 43.6 +/- 8 years) who had not previously received any type of periodontal therapy were selected. Bleeding on probing, probing depth, and clinical attachment level measurements were made with an automated probe. Patients were monitored at 2-month intervals until at least 2 sites exhibited > or =2 mm attachment loss. Two subgingival plaque samples from active sites were taken in 56 subjects and matched with 2 plaque samples from inactive sites in the same individuals.
Results: P. gingivalis was found in 75% of active sites and in 59.7% of inactive sites in 96% of the patients (P = 0.022). P. gingivalis at high levels of detection was significantly more frequent in active sites (48.2%) than in inactive sites (31.2%) (P = 0.014). A. actinomycetemcomitans was detected in 6.25% of active sites and in 12.5% of inactive sites in 11.6% of patients. P. intermedia was found in 33% of patients and at a significantly higher proportion in active sites (49.1%) than in inactive sites (30.3%) (P = 0.006). There was a significantly higher proportion of inactive sites (34.8%) than active sites (19.6%) without any of the 3 pathogens (P = 0.016). Bleeding on probing was significantly more associated with active sites with high levels of P. gingivalis and with active sites with P. intermedia than with inactive sites.
Conclusions: A high prevalence of P. gingivalis and P. intermedia was found in adult periodontitis, and the occurrence of these bacteria appears to be higher in Chileans than in other populations. No apparent association exists between A. actinomycetemcomitans and progressive adult periodontitis in Chileans.