The clinical and microbiological effect of locally-applied chlorhexidine gel 2%, amine fluoride gel 1.25%, stannous fluoride gel 4% or placebo gel in 40 periodontal pockets of 10 patients were studied. The gels were applied 3 x within 10 min. after mechanical debridement of the pockets. The treatment effect on the subgingival microflora was evaluated by microscopic and culture studies of the subgingival plaque samples. In addition, supragingival plaque, bleeding after probing and probing pocket depth were scored. Examination were carried out before and during a period of 36 weeks after treatment. At the start, the cultured microflora consisted mainly of anaerobic Gram-positive bacteria. Following treatment, the clinical parameters were significantly reduced. Concomitantly, the %s of spirochetes, motile rods and non-motile rods decreased significantly. A significant decrease was also found in the total anaerobic count, whereas the facultative counts remained at the same level found before treatment. This suggested that the treatment resulted in a mainly facultative subgingival microflora. The % Gram-negative rods showed a significant reduction after treatment, but returned to base line at week 12. Statistical analysis of the bacteriological and clinical examinations failed to demonstrate any significant differences between the 4 treatment groups. Thus, in comparison to the placebo gel, subgingival application of chlorhexidine gel 2%, amine fluoride gel 1.25% or stannous fluoride gel 4% did not augment the effect of mechanical debridement on bacteriological and clinical parameters during the experimental period of 36 weeks. However the indicated treatments resulted in a facultative subgingival microflora which is compatible with the host.

The effect of hand or ultrasonic instrumentation on the subgingival microflora of periodontal pockets was investigated. Pockets with probing depths of 6-9 mm were selected in 12 patients and were randomly assigned per patient to the experimental and control groups. After oral hygiene instruction, instrumentation of the experimental pockets was carried out either by ultrasonic or by hand instruments in a split-mouth design. The treatment effect on the subgingival microbiota was evaluated by microscopic and culture studies of subgingival plaque samples, while in addition, supragingival plaque, bleeding after probing and probing pocket depth were scored. Examinations were carried out before and 7, 21 and 49 days after treatment. The hand and ultrasonic treatments were equally effective in reducing probing pocket depths and bleeding scores. At the end of the experimental period, the probing depths of 54% of the hand-treated pockets and 43% of the ultrasonic-treated pockets were reduced to 4 mm or less while the bleeding scores were reduced to 29% and 22%, respectively. The analysis of microscopical and cultural data did not show any differences between hand and ultrasonic debridement. Both treatments reduced the microscopical counts of rods, spirochetes and motiles and reduced the total colony-forming units and number of black-pigmented Bacteroides and Capnocytophaga, resulting in a subgingival microbiota consistent with periodontal health.

The short-term bactericidal effect of 2% chlorhexidine gel, 4% stannous fluoride gel or amine fluoride gel containing 1.25% fluoride on the subgingival microflora was determined in 40 periodontal pockets of 10 patients. The antimicrobial gels or placebo gel were applied in 5-9 mm deep periodontal pockets 3 times within 10 min. Before and 30 min after the applications, samples were taken of the subgingival microflora for determination of the total number of bacteria as well as the number of black pigmented Bacteroides. Reductions of the total number of bacteria were found in all test groups. The reductions found in the pockets treated with chlorhexidine gel or stannous fluoride gel were significantly greater than the reduction found in the pockets treated with a placebo gel. A significant reduction of black-pigmented Bacteroides was found after treatment with chlorhexidine gel or amine fluoride gel. It is concluded that 2% chlorhexidine gel or 4% stannous fluoride gel has a more than 99% reduction effect on the microflora of periodontal pockets within 30 min after application.

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In edentulous patients, the microbial colonization of permucosal implants of sintered hydroxyapatite was studied. Samples were taken from mucosa and dentures before insertion of implants and from supra- and subgingival sites two to 10 weeks after insertion. In total, five patients and 10 implants with clinically healthy peri-implant tissues were studied. The samples were investigated by dark-field microscopy and anaerobic culture. The supragingival plaque of the implants was dominated by Gram-positive cocci and rods, the subgingival plaque by Haemophilus spp. and Veillonella parvula. A group of bacteria was found specifically related to the implants: Actinomyces odontolyticus, Peptostreptococcus micros, Haemophilus actinomycetemcomitans, Eikenella corrodens, Capnocytophaga sputigena, and Leptotrichia buccalis. Black-pigmented Bacteroides was not found in any of the examined samples. Spirochetes were observed in denture plaque samples and in supragingival plaque of the implants. It is concluded that bacteria known as potential periodontal pathogens colonize the permucosal implants in the first weeks after insertion. The presence of these species seems to be dependent on the ecological factors provided by the artificial gingival crevice of the permucosal implants in the edentulous mouth.