Dental plaque samples from (i) subjects with no apparent oral disease, (ii) mentally retarded subjects with periodontal disease, and (iii) subjects with active caries were collected in three transport media viz. a dithiothreitol poised balanced mineral salt solution designated as reduced transport fluid (RTF), VMG II, and modified Stuart medium (SBL). The samples were dispersed by sonic treatment, diluted in the respective medium in which they were collected, and cultured on MM10 sucrose agar. The efficiency of the transport media in the survival of dental plaque flora was determined by comparing the quantitative recovery (expressed as percentage of the initial viable count) from the specimens stored for various lengths of time. The data showed a great variation in the recovery of the oral bacterial flora from the plaque samples. VMG II and SBL served better than RTF as storage media for non-disease-associated dental plaque cultured under strict anaerobic conditions. Recoveries of bacteria from periodontal plaque specimens stored in RTF were higher than SBL and VMG II under identical conditions. The organisms present in the carious plaque samples appeared to survive much better in RTF and VMG II than in SBL as determined by conventional anaerobic culturing technique. However, VMG II showed a higher recovery of organisms from these specimens with an increase in the storage period, suggesting multiplication of the plaque flora. RTF did not allow the growth of oral bacterial flora under all experimental conditions. On the basis of the relative performance of these media it is suggested that RTF is a statisfactory medium for the transport of oral bacteria present in the samples.

In this report over 400 subgingival plaque samples taken from over 110 patients were examined microscopically and culturally for 30 bacterial parameters. The patients could be placed into six disease categories based upon clinical criteria. The bacterial profile of each clinical category was generally distinctive of that category. Periodontal patients who had been successfully treated and maintained had plaques that were populated by significantly higher proportions of Streptococcus sanguis, Actinomyces viscosus, A. odontolyticus and S. mutans and significantly lower proportions of B. gingivalis and spirochetes compared to the five untreated disease categories. The spirochetes were the overwhelming microbial type in the plaques of adult periodontitis (AP) patients, averaging about 45% of the microscopic count. The bacteriological results could not distinguish between ADA Type III and IV periodontitis, suggesting that the same type of infection was occurring in an active site in any AP patient. The patients designated as early onset periodontitis (EOP) differed from the other patients by their relative youth and by their significantly higher proportions of Bacteroides gingivalis and/or B. intermedius. Two types of EOP were recognized in which the most diseased variant was characterized by having an average of 49% spirochetes in the plaque. Four localized juvenile periodontitis (LJP) patients were notable in not having detectable A. actinomycetemcomitans. The data indicate that the various types of periodontitis, with the possible exception of LJP are specific anaerobic infections involving spirochetes and to a lesser extent B. gingivalis and B. intermedius.

This study revealed that the quantity of baeteria filtered from the base of Class V cavity restorations were directly related to the type of medicament used. Of the brands studied: composite, amalgam, sitieate, and guttapereha -eaeh produeed varying numbers of bacterial eolonies, whereas zinc oxide and eugenol eement showed none. Histopathology of the pulps eorrelated direetly to the mierobiologieal data.

Plaque samples from 22 ulcerated sites in eight patients with ANUG were cultured using quantitative anaerobic procedures and were examined microscopically. The partial characterization of the predominant cultivable flora revealed a constant flora comprised of a limited number of bacterial types and a variable flora composed of a heterogeneous array of bacterial types. This constant flora would appear to be pathognomonic of acute necrotizing ulcerative gingivitis (ANUG) and included the various Treponema and Selenomonas sp., which comprised about 32 and 6%, respectively, of the microscopic count; B. melaninogenicus ssp. intermedius and Fusobacterium sp., which averaged 24 and 3%, respectively, of the viable count. One week of metronidazole treatment caused a prompt resolution of clinical symptoms, which coincided with a significant reduction in the plaque proportions of the Treponema sp., B. melaninogenicus ssp., intermedius and Fusobacterium sp. for at least 2 to 3 months following treatment. Thus, the same anaerobic species which were numerically associated with the ANUG lesion were also selectively reduced in the plaque flora following resolution of the infection. This supports a role for the above species in the ulcerative stage of the lesion but does not demonstrate that these specific anaerobes initiated the infection. although not confirmed by the data, it was proposed that these particular anaerobic species gained ascendency in the plaque as a result of being selected through the availability of host-derived nutrients in individuals who had undergone certain physiological and psychological stresses.

Sunnnary-Tooth surface plaque was removed from 11 institutional~ed individuats and cultured on agar plates in an anaerobic chamber. The recovery of organisms on a dilute trypticase yeast extract medium (MMIO), incubated anaerobically, averaged 33 & 26 per cent of the microscopic count. Growth on MMlO, under aerobicconditions averaged 8 i: 5 per cent. The anaerobe to aerobe recovery ratio on medium MM10 was about 4. Six hundred and seventy-one isoiates grew on subculture and were partially characterized. About half the isolates were not capable of lowering the pH in glucose PREDOMINANT CULTIVABLE FLORA OF TDOTH SURFACE PLAQUE

A total of 80 oral strains of Bacteroides gingivalis, B. asaccharolyticus, B. melaninogenicus subsp. intermedius, B. melaninogenicus subsp. melaninogenicus, Capnocytophaga, Treponema denticola, and T. vincentii were characterized with the API ZYM system for 19 enzyme activities. Comparison of anaerobic and aerobic incubation with nine reference strains of these organisms showed no important differences. The key differential tests for black-pigmented Bacteroides strains and treponemes of oral origin were trypsin, a-glucosidase, and N-acetyl-13glucosaminidase. All Capnocytophaga strains produced distinctive aminopeptidase activities but varied in their glycosidic capabilities. The presence of a trypsin-like activity in B. gingivalis, T. denticola, and a group of Capnocytophaga strains may contribute to tissue destruction in periodontal disease.

The quantitative recovery of bacteria from single localized sites, namely the interproximal plaque over a carious lesion and the underlying carious dentine, was undertaken. The samples were collected with minimal oxygen exposure and after dispersion and serial dilution were plated on mitis salivarius agar and various formulations of MM10 agar (a dilute trypticase, yeast extract medium). Higher total counts, Strep, mutans and Strep, sanguis counts were obtained on MM10 supplemented with 5% sucrose. Strep, mutans accounted for 3% of the plaque isolates and 24% of the dentinal isolates. Lactobacillus casei was a prominent organism averaging about 21% of the dentinal isolates.

Twenty-five subjects with previously excellent hygiene and healthy gingiva developed heavy plaque accumulations and bleeding or nonbleeding gingivitis about certain papilla after 21 days of no oral hygiene. Gingival marginal plaque about a single papilla was collected at 0, 1, 2, and 3 weeks of no oral hygiene.in each subject. The plaque was dispersed, serially diluted, and plated on MM10 sucrose agar in an oxygen-free atmosphere. From 50 to 100 colonies from a single high-dilution plate were characterized for each sample. Over 8,500 isolates were partially characterized and placed into one of 29 taxonomic species or groups. The flora was predominantly gram-positive at all time periods. Streptococcal species dominated in the 0-and 1-week-old plaques, i.e. 62 and 43% of the colonyforming units (CFU), but dropped to 26 to 32% of the CFU in the 2-and 3-weekold plaques. Actinomyces species dominated in the older plaques, i.e., 40 to 50% of the CFU. Actinomyces israelii was the most prominent species in the older plaques. Veillonella accounted for 15 to 20% of the CFU at all time periods. Although the other gram-negative species increased with time, collectively they averaged less than 5% of the CFU at week 3. The shift from a Streptococcusdominated plaque to an Actinomyces-dominated plaque was the most striking microbial change observed as the plaque aged.