Recently published taxonomic studies of viridans streptococci have resulted in several changes in the nomenclature and definition of oral streptococcal species. With this background, the ecology of streptococci in the oropharyngeal cavities was reinvestigated. The results based on the examination of 1426 streptococcal isolates confirmed and extended earlier findings. Apart from mature supragingival plaque, which contained a mixture of all orally encountered streptococci, each site showed a characteristic streptococcal flora. Initial dental plaque formation is primarily associated with Streptococcus sanguis, Streptococcus mitis biovar 1 and Streptococcus oralis. Our investigation showed that S. sanguis and S. mitis biovar 1 were the most prominent streptococci, also on buccal mucosa. In contrast, S. oralis was almost exclusively found in initial dental plaque. Streptococcus gordonii, formerly part of S. sanguis, was found in small numbers on the oropharyngeal mucosa and in mature supragingival plaque. The dorsum of the tongue was dominated by S. mitis biovar 2 and Streptococcus salivarius, the latter of which was predominant also on the pharyngeal mucosa. Streptococcus anginosus was by far the most predominant streptococcus in subgingival plaque. Immunoglobulin A1 (IgA1) protease-producing streptococci were primarily isolated from initial dental plaque and from the buccal mucosa. This lends further support to the concept of IgA1 proteases being important for the ability of streptococci to evade the local immune defence during their initial colonization of certain oral surfaces.
The Royal Dental College. Aarhus. adult periodonti tis Pedrazzoli K Kilian A1 and Karring T Comparable clinical and microbiological eflects of topical subgingival application of a 25% metronidazole gel and scaling in the treatment of adult periodontitb. J CIin Periodontol 1992; 19: 715-722.Abstracr. The aim of the study was to compare the clinical and microbiological effects Of topical application of a metronidazole gel and a single session of subgingival scaling in the treatment of adult periodontitis. An open. randomized controlled clinical study design was employed. Each of 24 subjects received the 2 treatments simultaneously each in 2 randomly selected quadrants of the dentition. The metronidazole, 25% gel was applied subgingivally on days 0 and 7. Scaling was camed out in one quadrant on day 0 and in one quadrant on day 7. Clinical and microbiological examinations were camed out before treatment and on days 2 I, 49,9 I , 133, and I 75 of the experimental period. The microbiological analyses included determination of total anaerobically cultivable bacteria, and relative proportions of anaerobes, aerobes, black-pigmented anaerobic Gram negative rods. Actinobacillus ac.rinom.vcetemcomitans, streptococci. and spirochetes. Both treatments were effective in reducing probing pocket depth and bleeding on probing. Metronidazole tended to be a little better than scaling during the study period and the clinical effects of both treatments persisted during the whole 6 months observation period. Local metronidazole treatment induced a significant and long-lasting shift in the subgingival flora towards a composition more compatible with health and comparable to that obtained by mechanical debridemem. Proportions of black pigmented anaerobes including Prevotellu intermedia, and the number of spirochetes were significantly r e d u d after both treatments with a concomitant increase in the proportions of streptococci. While scaling resulted in a statistically significant increase in the proportion of A. "ctinom)'cetrmc.omitans. this was avoided after metronidzole treatment. No selection or emergence of bacteria with reduced susceptibility to metronidazole was observed during the study. The use of a topically applied metronidazole 25% dental gel seems to be as effective as conventional mechanical therapy in the treatment of adult periodontitis.
The purpose of this study was to evaluate, on a short-term basis, the clinical and microbiological effects of a single course of scaling and root planing as compared with those obtained by flap surgery in patients with moderate to advanced periodontitis. 11 patients participated in the study. Using a split-mouth design, one quadrant of the mouth was treated with reverse bevel flap surgery, whereas the contralateral one was subjected to a single course of scaling and root planing. 2 approximal sites on single-rooted teeth with a pocket depth greater than or equal to 5 mm were monitored clinically and microbiologically for 16 weeks after active treatment. Both techniques resulted in a gain of probable attachment levels, a reduction in bleeding on probing and a reduced mean pocket depth, although 31.2% of the sites in the scaling and root planing group still had 6-7 mm deep pockets at 8 and 16 weeks after treatment. Both techniques reduced median relative proportions and frequencies of detection of black-pigmented Bacteroides species. A highly statistically significant increase (p less than 0.01) in median proportions of oral streptococci was recorded only for surgery within the 1st month post-operatively. No correlation was found between residual pocket depth and any of the microbiological parameters considered in the study, suggesting that residual pocket depth does not exert a significant influence on bacterial subgingival recolonization after therapy. The results from this study suggest that surgery can be as effective as scaling and root planing in favoring the establishment of micro-organisms compatible with periodontal health, although this effect is limited to the 1st month after therapy.
The aim of the present study was: (1) to assess longitudinally the occurrence of Actinobacillus actinomycetemcomitans (Aa) in young subjects wearing fixed orthodontic appliances compared to matched appliance-free controls; (2) to determine whether the presence of the micro-organism at baseline could influence the periodontal status assessed 3 years later. 70 subjects, 27 male and 43 female, aged between 12 and 20 years participated in the study: 35 subjects under orthodontic treatment with fixed appliances for at least 6 months, and 35 appliance-free individuals matched for age and gender. All subjects were free of clinically demonstrable loss of attachment. They all received oral hygiene instructions 2x during the 2 months preceding the first clinical and microbiological examination. No subgingival instrumentation was performed between baseline and the 3-year examination. Clinical parameters included gingival bleeding index (GBI), pocket probing depth (PPD) and measurements of attachment level (AL). Statistically significant differences were reported regarding frequency of detection of Aa between both groups at each examination. The %s of orthodontic subjects infected with Aa at the baseline and at the 3-year examination were 86% and 80%, respectively, while the corresponding figures for control subjects were 16.6% and 26.6%. The frequency distribution of %s of Aa in the total anaerobic subgingival flora among control subjects remained fairly stable, whereas the proportion of orthodontic subjects yielding Aa at a concentration > or = 1.0% dropped significantly from 32% at baseline to 19% at the 3-year visit. Calculations of the relative risk for increasing GBI and PPD in both groups when Aa was present at baseline, revealed that the orthodontic subjects positive for Aa had a negligible relative risk of experiencing worse periodontal conditions compared to orthodontic patients where Aa was not detected at baseline. In contrast, control subjects initially infected with Aa presented with a risk for increased GBI 6.6x higher than that for subjects without Aa. In conclusion, the present study confirmed previous cross-sectional findings reporting that young individual with an integer periodontium wearing fixed orthodontic appliances harbor Aa with a statistically significant greater frequency than appliance-free matched controls. However, although orthodontic patients exhibited more inflammation, their deteriorated clinical conditions could not be accounted for by the sole presence of Aa in their sulci. In contrast, appliance-free young subjects initially infected with Aa had a higher risk of experiencing more gingival inflammation than subjects without the bacterium during a 3-year observation period.
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