Aggressive Periodontitis: Inflammation and loss of PERIODONTIUM that is characterized by rapid attachment loss and bone destruction in the presence of little local factors such as DENTAL PLAQUE and DENTAL CALCULUS. This highly destructive form of periodontitis often occurs in young people and was called early-onset periodontitis, but this disease also appears in old people.Periodontitis: Inflammation and loss of connective tissues supporting or surrounding the teeth. This may involve any part of the PERIODONTIUM. Periodontitis is currently classified by disease progression (CHRONIC PERIODONTITIS; AGGRESSIVE PERIODONTITIS) instead of age of onset. (From 1999 International Workshop for a Classification of Periodontal Diseases and Conditions, American Academy of Periodontology)Chronic Periodontitis: Chronic inflammation and loss of PERIODONTIUM that is associated with the amount of DENTAL PLAQUE or DENTAL CALCULUS present. Chronic periodontitis occurs mostly in adults and was called adult periodontitis, but this disease can appear in young people.Periodontal Pocket: An abnormal extension of a gingival sulcus accompanied by the apical migration of the epithelial attachment and bone resorption.Periodontal Attachment Loss: Loss or destruction of periodontal tissue caused by periodontitis or other destructive periodontal diseases or by injury during instrumentation. Attachment refers to the periodontal ligament which attaches to the alveolar bone. It has been hypothesized that treatment of the underlying periodontal disease and the seeding of periodontal ligament cells enable the creating of new attachment.Dental Scaling: Removal of dental plaque and dental calculus from the surface of a tooth, from the surface of a tooth apical to the gingival margin accumulated in periodontal pockets, or from the surface coronal to the gingival margin.Aggregatibacter actinomycetemcomitans: A species of Gram-negative, facultatively anaerobic spherical or rod-shaped bacteria indigenous to dental surfaces. It is associated with PERIODONTITIS; BACTERIAL ENDOCARDITIS; and ACTINOMYCOSIS.Periodontal Index: A numerical rating scale for classifying the periodontal status of a person or population with a single figure which takes into consideration prevalence as well as severity of the condition. It is based upon probe measurement of periodontal pockets and on gingival tissue status.Gingival Crevicular Fluid: A fluid occurring in minute amounts in the gingival crevice, believed by some authorities to be an inflammatory exudate and by others to cleanse material from the crevice, containing sticky plasma proteins which improve adhesions of the epithelial attachment, have antimicrobial properties, and exert antibody activity. (From Jablonski, Illustrated Dictionary of Dentistry, 1982)Dental Plaque Index: An index which scores the degree of dental plaque accumulation.Root Planing: A procedure for smoothing of the roughened root surface or cementum of a tooth after subgingival curettage or scaling, as part of periodontal therapy.Gingival Hemorrhage: The flowing of blood from the marginal gingival area, particularly the sulcus, seen in such conditions as GINGIVITIS, marginal PERIODONTITIS, injury, and ASCORBIC ACID DEFICIENCY.Pasteurellaceae: A family of coccoid to rod-shaped nonsporeforming, gram-negative, nonmotile, facultatively anaerobic bacteria that includes the genera ACTINOBACILLUS; HAEMOPHILUS; MANNHEIMIA; and PASTEURELLA.Gingiva: Oral tissue surrounding and attached to TEETH.Occlusal Adjustment: Selective grinding of occlusal surfaces of the teeth in an effort to eliminate premature contacts and occlusal interferences; to establish optimal masticatory effectiveness, stable occlusal relationships, direction of main occlusal forces, and efficient multidirectional patterns, to improve functional relations and to induce physiologic stimulation of the masticatory system; to eliminate occlusal trauma; to eliminate abnormal muscle tension; to aid in the stabilization of orthodontic results; to treat periodontal and temporomandibular joint problems; and in restorative procedures. (From Jablonski, Dictionary of Dentistry, 1992)Alveolar Bone Loss: Resorption or wasting of the tooth-supporting bone (ALVEOLAR PROCESS) in the MAXILLA or MANDIBLE.Dental Plaque: A film that attaches to teeth, often causing DENTAL CARIES and GINGIVITIS. It is composed of MUCINS, secreted from salivary glands, and microorganisms.Gingivitis: Inflammation of gum tissue (GINGIVA) without loss of connective tissue.Selenomonas: Curved bacteria, usually crescent-shaped rods, with ends often tapered, occurring singly, in pairs, or short chains. They are non-encapsulated, non-sporing, motile, and ferment glucose. Selenomonas are found mainly in the human buccal cavity, the rumen of herbivores, and the cecum of pigs and several rodents. (From Bergey's Manual of Determinative Bacteriology, 9th ed)Subgingival Curettage: Removal of degenerated and necrotic epithelium and underlying connective tissue of a periodontal pocket in an effort to convert a chronic ulcerated wound to an acute surgical wound, thereby insuring wound healing and attachment or epithelial adhesion, and shrinkage of the marginal gingiva. The term is sometimes used in connection with smoothing of a root surface or ROOT PLANING. (Jablonski; Illustrated Dictionary of Dentistry, 1982)Periodontium: The structures surrounding and supporting the tooth. Periodontium includes the gum (GINGIVA), the alveolar bone (ALVEOLAR PROCESS), the DENTAL CEMENTUM, and the PERIODONTAL LIGAMENT.Porphyromonas gingivalis: A species of gram-negative, anaerobic, rod-shaped bacteria originally classified within the BACTEROIDES genus. This bacterium produces a cell-bound, oxygen-sensitive collagenase and is isolated from the human mouth.Prevotella intermedia: A species of gram-negative, anaerobic, rod-shaped bacteria originally classified within the BACTEROIDES genus. This bacterium is a common commensal in the gingival crevice and is often isolated from cases of gingivitis and other purulent lesions related to the mouth.Periapical Periodontitis: Inflammation of the PERIAPICAL TISSUE. It includes general, unspecified, or acute nonsuppurative inflammation. Chronic nonsuppurative inflammation is PERIAPICAL GRANULOMA. Suppurative inflammation is PERIAPICAL ABSCESS.Actinobacillus Infections: Infections with bacteria of the genus ACTINOBACILLUS.Periodontal Debridement: Removal or disruption of DENTAL DEPOSITS and plaque-retentive DENTAL CALCULUS from tooth surfaces and within the periodontal pocket space without deliberate removal of CEMENTUM as done in ROOT PLANING and often in DENTAL SCALING. The goal is to conserve dental cementum to help maintain or re-establish healthy periodontal environment and eliminate PERIODONTITIS by using light instrumentation strokes and nonsurgical techniques (e.g., ultrasonic, laser instruments).Fibromatosis, Gingival: Generalized or localized diffuse fibrous overgrowth of the gingival tissue, usually transmitted as an autosomal dominant trait, but some cases are idiopathic and others produced by drugs. The enlarged gingiva is pink, firm, and has a leather-like consistency with a minutely pebbled surface and in severe cases the teeth are almost completely covered and the enlargement projects into the oral vestibule. (Dorland, 28th ed)Bacteroides: A genus of gram-negative, anaerobic, rod-shaped bacteria. Its organisms are normal inhabitants of the oral, respiratory, intestinal, and urogenital cavities of humans, animals, and insects. Some species may be pathogenic.Metronidazole: A nitroimidazole used to treat AMEBIASIS; VAGINITIS; TRICHOMONAS INFECTIONS; GIARDIASIS; ANAEROBIC BACTERIA; and TREPONEMAL INFECTIONS. It has also been proposed as a radiation sensitizer for hypoxic cells. According to the Fourth Annual Report on Carcinogens (NTP 85-002, 1985, p133), this substance may reasonably be anticipated to be a carcinogen (Merck, 11th ed).Amoxicillin: A broad-spectrum semisynthetic antibiotic similar to AMPICILLIN except that its resistance to gastric acid permits higher serum levels with oral administration.Case-Control Studies: Studies which start with the identification of persons with a disease of interest and a control (comparison, referent) group without the disease. The relationship of an attribute to the disease is examined by comparing diseased and non-diseased persons with regard to the frequency or levels of the attribute in each group.Bacteroidaceae Infections: Infections with bacteria of the family BACTEROIDACEAE.Exotoxins: Toxins produced, especially by bacterial or fungal cells, and released into the culture medium or environment.Statistics, Nonparametric: A class of statistical methods applicable to a large set of probability distributions used to test for correlation, location, independence, etc. In most nonparametric statistical tests, the original scores or observations are replaced by another variable containing less information. An important class of nonparametric tests employs the ordinal properties of the data. Another class of tests uses information about whether an observation is above or below some fixed value such as the median, and a third class is based on the frequency of the occurrence of runs in the data. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed, p1284; Corsini, Concise Encyclopedia of Psychology, 1987, p764-5)Interleukin-1beta: An interleukin-1 subtype that is synthesized as an inactive membrane-bound pro-protein. Proteolytic processing of the precursor form by CASPASE 1 results in release of the active form of interleukin-1beta from the membrane.Periodontal Diseases: Pathological processes involving the PERIODONTIUM including the gum (GINGIVA), the alveolar bone (ALVEOLAR PROCESS), the DENTAL CEMENTUM, and the PERIODONTAL LIGAMENT.Treponema denticola: A species of bacteria in the family SPIROCHAETACEAE, frequently isolated from periodontal pockets (PERIODONTAL POCKET).