Hector Dario Taveras

Bio: Hector Dario Taveras is an academic researcher from Universidad Autónoma de Santo Domingo. The author has an hindex of 1, co-authored 1 publications receiving 81 citations.

Subgingival Microflora of Advanced Periodontitis in the Dominican Republic

Abstract: A study of the predominant subgingival microflora was carried out in 24 periodontitis patients, 18 to 60 years of age, in Santo Domingo, Dominican Republic. Paper point sampling, transport in VMGA III, and conventional microbiological techniques were utilized. Direct microscopic examination revealed that cocci and nonmotile organisms made up 85% of the total organisms and spirochetes as little as 3%. Nonselective culturing showed Gram-negative organisms to constitute 53% of total isolates. Fusobacterium nucleatum averaged 15%, black-pigmented anaerobes 7%, and Peptostreptococcus micros 10% of the cultivable microflora. Enteric rods and acinetobacter species were recovered from 16 patients and comprised 23% of the cultivable flora. Enterobacter cloacae occurred in 8 patients, Klebsiella oxytoca in 3 patients, and 7 other species in 10 patients. Parallel studies have found a significantly lower prevalence of enteric rods in advanced periodontitis patients in the USA. In conclusion, fewer spirochetes and mar...

Polymerase chain reaction detection of 8 putative periodontal pathogens in subgingival plaque of gingivitis and advanced periodontitis lesions

Abstract: A 16S rRNA-based polymerase chain reaction (PCR) detection method was used to determine the prevalence of Actinobacillus actinomycetemcomitans, Bacteroides forsythus, Campylobacter rectus, Eikenella corrodens, Porphyromonas gingivalis, Prevotella intermedia. Prevotella nigrescens and Treponema denticola in subgingival specimens of 50 advanced periodontitis, 50 adult gingivitis and 50 pediatric gingivitis subjects. The optimal PCR conditions were determined for each study species. Agarose gel electrophoresis of PCR products from each study species revealed a single band of the predicted size. Restriction enzyme digestion of amplicons confirmed the specificity of the amplification. PCR detection limits were in the range of 25-100 cells. No cross-reactivity with other oral micro-organisms or nonspecific amplification was observed. The prevalence by PCR in advanced periodontitis, adult gingivitis and pediatric gingivitis subjects was 30%, 14% and 14% for A. actinomycetemcomitans, 86%, 18% and 8% for B. forsythus, 74%, 52% and 78% for C. rectus, 80%, 70% and 66% for E. corrodens, 70%, 10% and 14% for P. gingivalis, 58%, 12% and 18% for P. intermedia, 52%, 20% and 22% for P. nigrescens, and 54%, 16% and 16% for T. denticola, respectively. The prevalence was higher in the advanced periodontitis group than in both adult gingivitis and pediatric gingivitis for A. actinomycetemcomitans, B. forsythus, P. gingivalis, P. intermedia, P. nigrescens and T. denticola at P < 0.01, and for E. corrodens at P < 0.05. The prevalence of C. rectus was significantly higher in the advanced periodontitis group than in the adult gingivitis group at P < 0.01. Matching results between PCR and culture occurred in 28% (B. forsythus) to 71% (A. actinomycetemcomitans) of the samples; the major discrepancy occurred in the PCR-positive/culture-negative category. Matching results between PCR and DNA probe methods were found in 84% of the subjects (B. forsythus) and 70% (P. gingivalis). Odds ratio analysis revealed statistically significant positive associations between 17 of the 28 possible combinations (P < 0.01). This study demonstrated the utility of a 16S rRNA-based PCR detection method for identifying important subgingival microorganisms. The results indicated a strong association between the study species and periodontitis. Several previously unreported symbiotic relationships were found between the 8 species tested.

Subgingival microbiota in healthy, well‐maintained elder and periodontitis subjects

Abstract: This investigation compared the site prevalence of 40 subgingival species in 30 periodontally healthy (mean age 36+/-9 years), 35 elders with a well-maintained periodontium (mean age 77+/-5) and 138 adult periodontitis subjects (mean age 46+/-11). Subgingival plaque samples were taken from the mesial aspect of each tooth (up to 28 samples) in the 203 subjects at baseline. The presence and levels of 40 subgingival taxa were determined in 5003 plaque samples using whole genomic DNA probes and checkerboard DNA-DNA hybridization. Clinical assessments including dichotomous measures of gingival redness, bleeding on probing, plaque accumulation and suppuration, as well as duplicate measures of pocket depth and attachment level, were made at 6 sites per tooth. The % of sites colonized by each species (prevalence) was computed for each subject. Differences in prevalence and levels among groups were sought using the Kruskal-Wallis test. Commonly detected species, such as Actinomyces naeslundii genospecies 2, Streptococcus sanguis and Streptococcus oralis did not differ significantly among subject groups. After adjusting for multiple comparisons, 4 species were significantly elevated and at greater prevalence in the periodontitis group. Mean % of sites (+/-SEM) colonized by Bacteroides forsythus was 10+/-3, 12+/-2 and 40+/-2 (p or = 5% of sampled sites. Mean prevalence for Porphyromonas gingivalis in healthy, elder and periodontitis subjects was 4+/-2, 5+/-2 and 23+/-2 respectively (p<0.001); for Treponema denticola 12+/-4, 10+/-3 and 30+/-2 (p<0.001) and for Selenomonas noxia 6+/-2, 7+/-2 and 19+/-2 (p<0.01). Similar differences among subject groups were observed when only sites with PD 0-4 mm were analyzed. The data suggest an etiologic role for B. forsythus, P. gingivalis, T. denticola and S. noxia in adult periodontitis.