In this study the microbiota associated with oral endosteal titanium hollow cylinder implants (ITI) was studied using microscopic, immunochemical and cultural methods. Samples from 5 edentulous patients with successfully incorporated implants serving as abutments for overdentures for more than one year were compared with samples from 7 patients with clinically failing implants. Unsuccessful sites were characterized by pocket probing depths of 6 mm or more, suppuration and visible loss of alveolar bone around the implant as visualized on radiographs. These sites harbored a complex microbiota with a large proportion of Gram-negative anaerobic rods. Black-pigmented Bacteroides and Fusobacterium spp. were regularly found. Spirochetes, fusiform bacteria as well as motile and curved rods were a common feature in the darkfield microscopic specimens of these sites. Control sites in the same patients harbored small amounts of bacteria. The predominant morphotype was coccoid cells. Spirochetes were not present, fusiform bacteria, motile and curved rods were found infrequently and in low numbers. The microbiota in control sites in unsuccessful patients and in site in successful patients were very similar. On the basis of these results, it is suggested that “periimplantitis” be regarded as a site specific infection which yields many features in common with chronic adult periodontitis.

The microbiota associated with successful or failing osseointegrated titanium implants.

Microbial etiological agents of destructive periodontal diseases

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.

National High Blood Pressure Education Program.

Background Authors were assigned the task to develop case definitions for periodontitis in the context of the 2017 World Workshop on the Classification of Periodontal and Peri-Implant Diseases and Conditions. The aim of this manuscript is to review evidence and rationale for a revision of the current classification, to provide a framework for case definition that fully implicates state-of-the-art knowledge and can be adapted as new evidence emerges, and to suggest a case definition system that can be implemented in clinical practice, research and epidemiologic surveillance. Methods Evidence gathered in four commissioned reviews was analyzed and interpreted with special emphasis to changes with regards to the understanding available prior to the 1999 classification. Authors analyzed case definition systems employed for a variety of chronic diseases and identified key criteria for a classification/case definition of periodontitis. Results The manuscript discusses the merits of a periodontitis case definition system based on Staging and Grading and proposes a case definition framework. Stage I to IV of periodontitis is defined based on severity (primarily periodontal breakdown with reference to root length and periodontitis-associated tooth loss), complexity of management (pocket depth, infrabony defects, furcation involvement, tooth hypermobility, masticatory dysfunction) and additionally described as extent (localized or generalized). Grade of periodontitis is estimated with direct or indirect evidence of progression rate in three categories: slow, moderate and rapid progression (Grade A-C). Risk factor analysis is used as grade modifier. Conclusions The paper describes a simple matrix based on stage and grade to appropriately define periodontitis in an individual patient. The proposed case definition extends beyond description based on severity to include characterization of biological features of the disease and represents a first step towards adoption of precision medicine concepts to the management of periodontitis. It also provides the necessary framework for introduction of biomarkers in diagnosis and prognosis.

https://onlinelibrary.wiley.com/doi/epdf/10.1111/jcpe.12945

Staging and grading of periodontitis: Framework and proposal of a new classification and case definition.

Although specific bacteria, dental plaque, and age are associated with periodontal disease, there are currently no reliable predictors of periodontitis severity. Studies in twins have suggested a genetic contribution to the pathogenesis of periodontitis, but previous attempts to identify genetic markers have been unsuccessful. The pro-inflammatory cytokines interleukin-1 (IL-1) and tumor necrosis factor alpha (TNF alpha) are key regulators of the host responses to microbial infection. IL-1 is also a major modulator of extracellular matrix catabolism and bone resorption. We report a specific genotype of the polymorphic IL-1 gene cluster that was associated with severity of periodontitis in non-smokers, and distinguished individuals with severe periodontitis from those with mild disease (odds ratio 18.9 for ages 40-60 years). Functionally, the specific periodontitis-associated IL-1 genotype comprises a variant in the IL-1B gene that is associated with high levels of IL-1 production. In smokers severe disease was not correlated with genotype. In this study, 86.0% of the severe periodontitis patients were accounted for by either smoking or the IL-1 genotype. This study demonstrates that specific genetic markers, that have been associated with increased IL-1 production, are a strong indicator of susceptibility to severe periodontitis in adults.

The interleukin-1 genotype as a severity factor in adult periodontal disease

T H E PURPOSE OF these studies was to investigate the microbiota in the apical portion of lesions of human periodontosis. The evidence that bacterial plaque is the major etiologic agent in human periodontal diseases has been documented in recent reviews.\" In addition a number of studies have examined the predominant cultivable microbiota of the normal gingival sulcus and the periodontal pocket. ,6 These reports suggest that differences may exist in the microbiota associated with normal and pathologic sites. No studies were available concerning the microbiota in the periodontosis lesion. Thus the present investigation was undertaken to deter­ mine the nature of the microbiota in the depths of the periodontosis pocket as a prerequisite to the understand­ ing of the role which microorganisms might play in this unusual clinical condition. Studies of the predominant cultivable microbiota of any oral site present a number of problems which if not appreciated may lead to information which is difficult to interpret. Such problems include difficulties in diagnos­ ing clinical disease status, sample taking, cultivation of the many diverse organisms and identification of the organisms once they have been isolated. For example, pooled samples examined in earlier studies probably obscured differences in bacterial composition between various sites by combining bacteria from periodontally involved areas with organisms from normal sites. In addition the inability to cultivate oxygen sensitive orga­ nisms and to classify many organisms resident in plaque led to further confusion. One of the most intriguing questions in periodontal research is whether specific agents cause specific forms of periodontal disease. In an earlier study of 14 patients diagnosed as having periodontosis, Newman and Socransky reported that periodontosis lesions contained significantly more gram-negative anaerobic rods than normal sites within the same patient. Control sites harbored microorganisms similar to those found in supragingival plaque of normal individuals. However, in the periodontal pocket areas, gram-negative anaerobic rods were dramatically increased in proportions compris­ ing 40 to 78% of the total cultivable microbiota. The majority of these organisms could not be identified by current classification schemes and were divided into five groups based on morphologic and physiologic character­ istics. Strains representing three of the five groups of gramnegative anaerobic rods were implanted in germ-free rats as monocontaminants by Irving et al., and New­ man and Socransky. In each case implantation of the organisms led to extensive alveolar bone destruction accompanied by a marked osteoclastic response without microscopically visable plaque formation or root caries. These studies suggested that specific gram-negative anaerobic rods may participate in the pathogenesis of periodontosis. The present investigation confirms and extends obser­ vations on the nature of the microbiota associated with periodontosis lesions. In addition, the nature of the gram-negative anaerobic rods present on molars and incisors of younger siblings of periodontosis patients as well as \"normal\" adolescents was sought. Finally, the pathogenic potential of representative strains of two of the major groups of isolated organisms was tested in gnotobiotic rats. The data presented represents cummulative information from earlier studies and the present investigation.

Studies of the Microbiology of Periodontosis

Background: Periodontitis is a bacterial disease modified by multiple risk factors. The pro-inflammatory cytokine interleukin-1 (IL-1) is a key regulator of the host responses to microbial infection and a major modulator of extracellular matrix catabolism and bone resorption. It has been reported that variations in the IL-1 gene cluster on chromosome 2 are associated with increased susceptibility to severe adult periodontitis. Methods: The present study evaluated the association between a composite IL-1 genotype, including allele 2 at each of two loci (IL-1A +4845 plus IL-1B +3954), and a broad spectrum of periodontally healthy to diseased patients in a population that is typically encountered in a dental practice setting. Ninety patients, non-smokers or former smokers with less than 10 pack-year (pk/yr) history, were recruited from a private dental practice. The major outcome variable was bone loss determined by computerized linear measurements of radiographs. Genotypes were analyzed from finger-stick bl...

Interleukin-1 genetic association with periodontitis in clinical practice

Using scanning electron microscopy, bacteria were found invading the epithelial wall of deep periodontal pockets in five out of eight cases. In one case, bacteria had reached the connective tissue. The following bacterial morphotypes were identified: cocci, short rods, filaments and spirochetes. A corncob-like formation with a few scattered spirochetes was found in one case between the junctional epithelial cells. Numerous cocci, rods and filaments were found in intercellular spaces of the epithelium in the lateral wall of the pocket and accumulating on the epithelial side of the basement lamina. Bacterial invasion of gingival tissue may have important pathogenic and therapeutic implications.

Bacterial invasion of gingiva in advanced periodontitis in humans.

The antimicrobial effect of stannous fluoride (SnF2) on suspected pathogenic morphotypes of bacterial plaque in chronic periodontal disease was assessed. Alterations in morphological groups of subgingival and supragingival plaque bacteria from three diseased sites and one periodontally healthy site were determined by darkfield microscopy in 10 male patients with advanced periodontitis. In addition, clinical indices were also measured. The three diseased sites received either 1.64% SnF2, 0.4% SnF2 or sterile saline by subgingival irrigation. The healthy site received sterile saline only. The patients were seen weekly over a 10-week period and at each appointment bacterial sampling and clinical indices were measured. Results indicated that 1.64% SnF2 caused a dramatic and sustained decrease of subgingival motile bacteria and spirochetes following irrigation. By the sixth week these bacteria returned to 50% of their original concentration. Bleeding index scores, which were significantly reduced, correlated positively to the reduction in motile bacteria and spirochetes. Sites irrigated with 0.4% SnF2 also demonstrated a similar pattern of reduction of motile bacteria and spirochetes but without their total elimination and a more rapid return to original levels. In the diseased sites receiving sterile saline there was a decrease in motile bacteria and spirochetes, corresponding with saline irrigation, which rapidly returned to baseline levels. The healthy control sites were unchanged. Supragingival plaque index scores did not correlate with the bleeding index, motile bacteria and spirochetes, or with subgingival irrigation.

Michael G. Newman

Papers

The interleukin-1 genotype as a severity factor in adult periodontal disease

Studies of the Microbiology of Periodontosis

Interleukin-1 genetic association with periodontitis in clinical practice

Bacterial invasion of gingiva in advanced periodontitis in humans.

Clinical and antimicrobial effect of stannous fluoride on periodontitis