THE AMERICAN ACADEMY OF PERIODONTOLOGY Glossary of Periodontal Te rms 4th Edition Copyright 200 I by The American Academy of Periodontology Suite 800 737 North Michigan Avenue Chicago, Illinois 60611-2690 All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, or otherwise without the express written permission of the publisher. ISBN 0-9264699-3-9 The first two editions of this publication were published under the title Glossary of Periodontic Terms as supplements to the Journal of Periodontology. First edition, January 1977 (Volume 48); second edition, November 1986 (Volume 57). The third edition was published under the title Glossary vf Periodontal Terms in 1992. ACKNOWLEDGMENTS The fourth edition of the Glossary of Periodontal Terms represents four years of intensive work by many members of the Academy who generously contributed their time and knowledge to its development. This edition incorporates revised definitions of periodontal terms that were introduced at the 1996 World Workshop in Periodontics, as well as at the 1999 International Workshop for a Classification of Periodontal Diseases and Conditions. A review of the classification system from the 1999 Workshop has been included as an Appendix to the Glossary. Particular recognition is given to the members of the Subcommittee to Revise the Glossary of Periodontic Terms (Drs. Robert E. Cohen, Chair; Angelo Mariotti; Michael Rethman; and S. Jerome Zackin) who developed the revised material. Under the direction of Dr. Robert E. Cohen, the Committee on Research, Science and Therapy (Drs. David L. Cochran, Chair; Timothy Blieden; Otis J. Bouwsma; Robert E. Cohen; Petros Damoulis; Connie Drisko; James B. Fine; Gary Greenstein; James E. Hinrichs; Martha J. Somerman; Vincent J. Iacono, Board Liaison; and Robert J. Genco, Consultant), as well as Drs. Sigmund Socransky and Henry Greenwell, served as peer reviewers for this edition of the Glossary. ABUTMENT: Tooth, root, or implant used to support --------i[A]I----- and/or anchor a fixed or removable prosthesis. INTERMEDIATE A.: Abutment located between ABERRANT: Varying or deviating from the usual or other abutments. normal course, form, or location. ACANTHOLYSIS: Dissolution of the intercellular ABFRACTION: Hypothetical tooth surface abrasion attachments within the prickle cell layer (stratum in conjunction with occlusal forces; data supporting spinosum) of stratified squamous epithelium. this term as a discrete clinical entity are not yet Classically seen in pemphigus vulgaris during vesicle available (See Abrasion; Erosion.) and bulla formation. ABRASION: Wearing away of a substance or structure ACANTHOSIS: Hyperplasia of the prickle cell layer through an abnormal mechanical process. Examples (stratum spinosum) of stratified squamous epithelium, include gingival and dental abrasions due to incorrect resulting in thickened rete ridges or widening of this brushing. layer. ABSCESS: Localized collection of purulent exudate ACATALASIA (Acatalasemia): Deficiency in the (pus) in a cavity formed by the disintegration of blood and tissues of the enzyme catalase, sometimes tissues. resulting in oral ulceration and destruction of alveolar ACUTE A.: An abscess of relative short duration, bone. typically producing pain and local inflammation. ACCRETION: Accumulation on the teeth of foreign APICAL A.: Inflammatory condition characterized by materials such as plaque, materia alba, and calculus. formation of purulent exudate involving the dental pulp or pulpal remnants and the tissues sun'ounding ACELLULAR: Lacking in cells. the apex of a tooth. ACHE: Any dull, continuous pain. Thought to be the CHRONIC A.: I. Abscess of comparatively slow psychological manifestation of c-fiber (slow, non­ development with little evidence of inflammation. myelinated) nociceptive impulses with origin outside There may be an intermittent discharge of purulent the central nervous system. matter. 2. Long-standing collection of purulent exudate. It may follow an acute abscess. See: ACQUIRED: Not congenital, but attained after birth. Abscess, Residual. Examples include acquired immunodeficiency (See GINGIVAL A.: A localized purulent infection that syndrome AIDS), acquired immunity and involves the marginal gingiva or interdental acquired reflexes. papilla. ACQUIRED CENTRIC: See: Occlusion, Centric PERICORONAL A.: A localized purulent infection ACQUIRED IMMUNE DEFICIENCY within the tissue surrounding the crown of a partially SYNDROME: See: AIDS. erupted tooth. PERIODONTAL A. (Parietal A.): Localized purulent ACTINOBACILLUS ACTINOMYCETEMCOMI­ inflammation in the periodontal tissues; also called TANS: Small, Gram-negative, non-motile, faculta­ lateral periodontal abscess. tively anaerobic, rod-shaped bacteria found in PULPAL A.: Inflammation of the dental pulp subgingival and marginal plaque. A periodontal characterized by the formation of purulent exudate. pathogen implicated in some forms of periodontitis. RESIDUAL A.: Abscess produced by the residues of a Linked most often with the aggressive periodontal previous inflammatory process. diseases. WANDERING A.: Abscess in which purulent material ACTINOMYCES ISRAELII: Gram-positive, non­ flows along a course of decreased resistance and motile, non-acid fast, non-spore forming, anaerobic discharges at a distant point. bacilli with a tendency to grow as branched filaments ABSORPTION: I. Passage of a substance into the in tissues. Commensals that usually coexist peace­ interior of another substance. 2. Passage of fluids or fully with their hosts, but under some conditions sub tances through tissues. 3. Attenuation of radiation emerge as opportunistic pathogens involved in energy by the substance through which it passes. infections of both soft tissues and teeth. 2 ACTINOMYCES NAESLUNDII: Gram-positive, root planing and surgical therapy, such as chemo­ non-motile, anaerobic bacteria that preferentially therapy, occlusal therapy, and restorative care. colonize the tongue and other mucosal surfaces; can ADSORPTION: The attachment of a substance to the also colonize the oral cavity prior to tooth eruption. surface of another. ACTINOMYCES VISCOSUS: Gram-positive, AEROBE: A microorganism that can live and grow in non-motile, facultatively anaerobic, filamentous, the presence of molecular oxygen. pleomorphic bacteria that form branched filaments. These indigenous microflora colonize the mouths of AEROBIC: Environmental conditions that contain humans and other animals and are associated with atmospheric levels of oxygen. Used in reference to gingivitis, periodontitis, and root caries. microorganisms that grow optimally under these conditions. See: Facultative. AC TINOMYCOSIS: Clinical infection caused by a species of the genus Actinomyces. Abscess formation AGRANULOCYTOSIS (Granulocytopenia): A is common and, in the cervicofacial form of the pathologic decrease in the number of circulating disease, usually drains to the skin surface. granulocytes-neutrophils, eosinophils, and basophils. ACUTE: I. Sharp, severe. 2. Denoting the swift onset and course of a disease. AIDS (ACQUIRED IMMUNE DEFICIENCY SYNDROME): A disease syndrome caused by ACUTE NECROTIZING ULCERATIVE the progressive loss of immune function that GINGIVITIS (ANUG): See: Periodontitis, characterizes the progression of human Necrotizing Ulcerative. immunodeficiency virus infection. This natural ACUTE NECROTIZING ULCERATIVE history is thought responsible for opportunistic, PERIODONTITIS (ANUP): See: Periodontitis, pernicious and eventually fatal conditions that include Necrotizing Ulcerative. Kaposi's sarcoma, Pneumocystis carinii pneumonia, and others. Oral lesions may include necrotizing ACYCLOVIR: A synthetic acyclic purine nucleoside ulcerative gingivitis (NUG), necrotizing ulcerative with selective antiviral activity against many, but not periodontitis (NUP), linear gingival erythema (LGE), all, herpes viruses. candidiasis, hairy leukoplakia, herpes simplex, and ADENITIS: Inflammation of a lymph node or gland. rapidly progressive periodontitis. ADENOPATHY: Pathologic enlargement of glands, ALLELE: One of two or more different genes that may especially lymphatic glands. occupy the same locus on a specific chromosome. 80 90 ADENOVIRUS: A DNA virus to nanometers in ALLERGEN: A substance capable of producing size. It can cause respiratory illness and conjunctivitis allergy or specific hypersensitivity. in humans. Human adenoviruses comprise at least 31 ALLERGY: The altered reactivity of a sensitized serotypes that can be divided into three groups on the individual on exposure to an allergen. basis of oncogenicity. ALLOGRAFT: See: Graft, Allograft. ADHERENCE: The act or quality of uniting two or more surfaces or parts. ALVEOLAR BONE: See: Bone, Alveolar. ADHESION: The property of remaining in close ALVEOLAR CREST: The most coronal portion of proximity; the molecular attraction existing between the alveolar process. the surfaces of contacting bodies. ALVEOLAR CREST FIBER: See: Fiber, Principal. ADJUSTMENT, OCCLUSAL: See: Occlusal ALVEOLAR MUCOSA: See: Mucosa, Alveolar. Adjustment. ALVEOLAR PROCESS: See: Process, Alveolar. ADJUNCTIVE TREATMENT: Supplementary and additional therapeutic procedures. In periodontics, it ALVEOLECTOMY: Removal of a portion of the generally refers to procedures other than scaling and alveolar process usually performed to achieve 3 acceptable ridge contour in preparation for ANGINA PECTORIS: Paroxysmal thoracic pain