The authors have taken the liberty of presenting this manuscript in two parts. The first is a brief primer on microbial ecology, because, although the importance of microbial ecology in periodontal diseases is widely recognized, most of us do not know precisely what is meant by the term. The second section is a rather extensive overview of current studies of oral microbial ecology based almost entirely on recent in vivo studies.

https://laurieximenez.files.wordpress.com/2011/02/ref-2_socransky-2005_p2000.pdf

Periodontal microbial ecology.

Comparison of surface roughness of oral hard materials to the threshold surface roughness for bacterial plaque retention: a review of the literature

A classification scheme for periodontal and peri-implant diseases and conditions is necessary for clinicians to properly diagnose and treat patients as well as for scientists to investigate etiology, pathogenesis, natural history, and treatment of the diseases and conditions. This paper summarizes the proceedings of the World Workshop on the Classification of Periodontal and Peri-implant Diseases and Conditions. The workshop was co-sponsored by the American Academy of Periodontology (AAP) and the European Federation of Periodontology (EFP) and included expert participants from all over the world. Planning for the conference, which was held in Chicago on November 9 to 11, 2017, began in early 2015. An organizing committee from the AAP and EFP commissioned 19 review papers and four consensus reports covering relevant areas in periodontology and implant dentistry. The authors were charged with updating the 1999 classification of periodontal diseases and conditions and developing a similar scheme for peri-implant diseases and conditions. Reviewers and workgroups were also asked to establish pertinent case definitions and to provide diagnostic criteria to aid clinicians in the use of the new classification. All findings and recommendations of the workshop were agreed to by consensus. This introductory paper presents an overview for the new classification of periodontal and peri-implant diseases and conditions, along with a condensed scheme for each of four workgroup sections, but readers are directed to the pertinent consensus reports and review papers for a thorough discussion of the rationale, criteria, and interpretation of the proposed classification. Changes to the 1999 classification are highlighted and discussed. Although the intent of the workshop was to base classification on the strongest available scientific evidence, lower level evidence and expert opinion were inevitably used whenever sufficient research data were unavailable. The scope of this workshop was to align and update the classification scheme to the current understanding of periodontal and peri-implant diseases and conditions. This introductory overview presents the schematic tables for the new classification of periodontal and peri-implant diseases and conditions and briefly highlights changes made to the 1999 classification. It cannot present the wealth of information included in the reviews, case definition papers, and consensus reports that has guided the development of the new classification, and reference to the consensus and case definition papers is necessary to provide a thorough understanding of its use for either case management or scientific investigation. Therefore, it is strongly recommended that the reader use this overview as an introduction to these subjects. Accessing this publication online will allow the reader to use the links in this overview and the tables to view the source papers (Table 1).

/pdf/a-new-classification-scheme-for-periodontal-and-peri-implant-160pyrsfm7.pdf

A new classification scheme for periodontal and peri-implant diseases and conditions - Introduction and key changes from the 1999 classification.

This article describes the subgingival microflora of the healthy periodontium, gingivitis, advanced adult periodontitis, and juvenile periodontitis. A total of seven to nine subjects were examined in each of the four periodontal clinical entities listed. The individual bacteriological samples included material from the base of a single periodontal pocket. The sampling, the treatment of the samples, and the bacteriological cultivations were carried out using continuous anaerobic techniques.

Briefly, the healthy gingival sulcus harbored a scant microflora dominated by Gram-positive organisms (85%), usually Streptococcus and facultative Actinomyces species. The development of gingivitis was accompanied by a marked increase in the total number of Gram-negative organisms. Fusobacterium nucleatum, Bacteroides melaninogenicus ss. intermedius, Haemophilus species, and other Gram-negative organisms comprised about 45% of the total gingivitis isolates. Streptococcus and facultative and anaerobic Actinomyces species constituted the majority of the Gram-positive gingivitis isolates. The micro-flora of advanced adult periodontitis was comprised mainly of Gram-negative anaerobic rods (about 75%), B. melaninogenicus ss. asaccharolyticus and F. nucleatum being the most predominant isolates. The deep pocket microflora in juvenile periodontitis was also made up mainly of Gram-negative organisms (about 65%), but was of a nature different from that of adult periodontitis, being predominated by isolates of Bacteroides species and other organisms of unknown species.

The present article also concerns factors of importance for the colonization of Gram-negative anaerobic rods in the oral cavity and periodontal pockets. In vitro experiments showed that cells of B. melaninogenicus ss. asaccharolyticus and other Gram-negative organisms attached in high numbers to epithelial cells, hydrosyapatite (HA) surface, and Gram-positive bacteria when suspended in phosphate-buffered saline; however, the bacterial attachment to epithelial cells and HA was strongly inhibited in the presence of human saliva and serum. In contrast, saliva and serum had little effect upon the attachment of Gram-negative bacteria to Gram-positive bacterial cells. These findings agreed well with data from an in vivo study, in which streptomycin-labeled cells of B. melaninogenicus ss. asaccharolyticus were introduced into the mouth of two volunteers. A significantly higher number of B. melaninogenicus cells was recovered from dental plaque than from the other oral surfaces studied.

The present series of studies has pointed to certain Gram-negative organisms as potential pathogens in rapidly progressing periodontal lesions. The available data on oral microbial ecology suggest that the presence of dental plaque containing Gram-positive organisms may be essential for the attachment and colonization of several Gram-negative species after their initial introduction into the mouth and the periodontal pocket area. The clinical relevance of these findings is discussed.

Subgingival microflora and periodontal disease

Relative distribution of bacteria at clinically healthy and periodontally diseased sites in humans

After 9–21 days without oral hygiene eleven experimental subjects with previously excellent oral hygiene and healthy gingivae developed heavy accumulations of plaque and generalized mild gingivitis. The individual rate of development of gingivitis was closely correlated with the rate of plaque accumulation. Characteristic bacteriological changes were revealed in the plaque along the gingival margin during this experiment. Initially, i.e. when the teeth were clean and the gingiva healthy, the extremely sparse plaque flora consisted almost exclusively of gram-positive cocci and rods. The first phase of plaque development occurred during the first 2 days without oral hygiene and consisted of a proliferation of the gram-positive cocci and rods and an addition of about 30 per cent gram-negative cocci and rods. During the second phase (after 1–4 days) fusobacteria and filaments appeared and increased until they each made up about seven per cent of the flora. During the third phase (after 4–9 days) the flora was supplemented with spirilla and spirochetes, and at the end of the period without oral hygiene each of these two groups of organisms accounted for about two per cent of the plaque flora. In specific areas the gingival condition was correlated with the composition of the plaque and it was found that mild gingivitis could be diagnosed clinically at approximately the same time as the complex flora was established. However, sub-clinical inflammation started much earlier, probably as a reaction to the first phases of plaque development. When oral hygiene was reinstituted, the plaque in most areas disappeared in 1–2 days and after 7–11 days the Plaque Index for each subject was as low as before the experiment. Correspondingly, after 1–2 days most tooth surfaces only harbored the original sparse flora of gram-positive cocci and rods. The gingival inflammation in an area usually disappeared one day after the plaque had been removed.

W H Wright

Papers

Experimental gingivitis in man. II. A longitudinal clinical and bacteriological investigation.