An updated classification of the periodontal manifestations and conditions affecting the course of periodontitis and the periodontal attachment apparatus, as well as of developmental and acquired conditions, is introduced. Case definitions and diagnostic considerations are also presented.

Objective: To review current knowledge on cytokine interactions and the cytokinemediated links between innate and adaptive immunity that are relevant to the pathophysiology of periodontitis. Materials and Methods: A structured review of the literature was undertaken to identify relevant research publications using a Medline search from 1950 to September 2010. The focus of the search was on the functional role of cytokines, i.e. their actions and responses relevant to the pathogenesis of periodontal disease rather than more descriptive studies of their expression in tissues and body fluids. It was not possible to conduct a traditional systematic review with a focussed question due to the heterogeneity of published research. Results: There is enormous heterogeneity in the periodontal literature in terms of experimental approaches. We have the deepest understanding of the role of the proinflammatory cytokines [e.g. interleukin (IL)-1b, tumour necrosis factor-a, IL-6] with accumulating data on T-cell regulatory cytokines (e.g. IL-12, IL-18), chemokines and cytokines which mediate bone cell development and function (e.g. receptor activator of NFkB ligand, osteoprotegerin). It is clear that there are multiple, overlapping and complex functional links between cytokines with regulatory control exerted at a number of levels and involving numerous cell types (both immune cells and resident cells in the periodontium). Conclusion: Cytokines appear to interact functionally in networks in the periodontium and integrate aspects of innate and adaptive immunity. However, our understanding is far from complete, particularly how molecular and cellular pathways relate to disease pathogenesis. We should adopt consistent experimental approaches to gain better insight into the totality of cytokine networks and how they drive immune responses in the periodontium.

Background A variety of systemic diseases and conditions can affect the course of periodontitis or have a negative impact on the periodontal attachment apparatus. Gingival recessions are highly prevalent and often associated with hypersensitivity, the development of caries and non‐carious cervical lesions on the exposed root surface and impaired esthetics. Occlusal forces can result in injury of teeth and periodontal attachment apparatus. Several developmental or acquired conditions associated with teeth or prostheses may predispose to diseases of the periodontium. The aim of this working group was to review and update the 1999 classification with regard to these diseases and conditions, and to develop case definitions and diagnostic considerations. Methods Discussions were informed by four reviews on 1) periodontal manifestions of systemic diseases and conditions; 2) mucogingival conditions around natural teeth; 3) traumatic occlusal forces and occlusal trauma; and 4) dental prostheses and tooth related factors. This consensus report is based on the results of these reviews and on expert opinion of the participants. Results Key findings included the following: 1) there are mainly rare systemic conditions (such as Papillon‐Lefevre Syndrome, leucocyte adhesion deficiency, and others) with a major effect on the course of periodontitis and more common conditions (such as diabetes mellitus) with variable effects, as well as conditions affecting the periodontal apparatus independently of dental plaque biofilm‐induced inflammation (such as neoplastic diseases); 2) diabetes‐associated periodontitis should not be regarded as a distinct diagnosis, but diabetes should be recognized as an important modifying factor and included in a clinical diagnosis of periodontitis as a descriptor; 3) likewise, tobacco smoking – now considered a dependence to nicotine and a chronic relapsing medical disorder with major adverse effects on the periodontal supporting tissues – is an important modifier to be included in a clinical diagnosis of periodontitis as a descriptor; 4) the importance of the gingival phenotype, encompassing gingival thickness and width in the context of mucogingival conditions, is recognized and a novel classification for gingival recessions is introduced; 5) there is no evidence that traumatic occlusal forces lead to periodontal attachment loss, non‐carious cervical lesions, or gingival recessions; 6) traumatic occlusal forces lead to adaptive mobility in teeth with normal support, whereas they lead to progressive mobility in teeth with reduced support, usually requiring splinting; 7) the term biologic width is replaced by supracrestal tissue attachment consisting of junctional epithelium and supracrestal connective tissue; 8) infringement of restorative margins within the supracrestal connective tissue attachment is associated with inflammation and/or loss of periodontal supporting tissue. However, it is not evident whether the negative effects on the periodontium are caused by dental plaque biofilm, trauma...

A review of the evidence for pathogenic mechanisms that may link periodontitis and diabetes Taylor JJ, Preshaw PM, Lalla E. A review of the evidence for pathogenic mechanisms that may link periodontitis and diabetes.Abstract Aims: To review the evidence for the molecular and cellular processes that may potentially link periodontal disease and diabetes. The pathogenic roles of cytokines and metabolic molecules (e.g. glucose, lipids) are explored and the role of periodontal bacteria is also addressed. Paradigms for bidirectional relationships between periodontitis and diabetes are discussed and opportunities for elaborating these models are considered. Methods: Database searches were performed using MeSH terms, keywords, and title words. Studies were evaluated and summarized in a narrative review. Results: Periodontal microbiota appears unaltered by diabetes and there is little evidence that it may influence glycaemic control. Small-scale clinical studies and experiments in animal models suggest that IL-1b, TNF-a, IL-6, OPG and RANKL may mediate periodontitis in diabetes. The AGE-RAGE axis is likely an important pathway of tissue destruction and impaired repair in diabetesassociated periodontitis. A role for locally activated pro-inflammatory factors in the periodontium, which subsequently impact on diabetes, remains speculative. Conclusion: There is substantial information on potential mechanistic pathways which support a close association between diabetes and periodontitis, but there is a real need for longitudinal clinical studies using larger patient groups, integrated with studies of animal models and cells/tissues in vitro.

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