Periodontium: The Tooth Supporting Structures PDF

CHAPTER 1 Periodontium: The Tooth Supporting Structures Copyright © 2024 by Jones & Bartlett Learning, LLC. www.jblearning.com. Periodontium  Functional system of tissues that surrounds teeth and attaches them to jawbone Copyrigh...

CHAPTER 1 Periodontium: The Tooth Supporting Structures Copyright © 2024 by Jones & Bartlett Learning, LLC. www.jblearning.com. Periodontium  Functional system of tissues that surrounds teeth and attaches them to jawbone Copyright © 2024 by Jones & Bartlett Learning, LLC. www.jblearning.com  Also called: © Wolters Kluwer  Supporting tissues of teeth  Attachment apparatus  Copyright © 2024 by Jones & Bartlett Learning, LLC. www.jblearning.com Healthy Periodontium © Wolters Kluwer  Copyright © 2024 by Jones & Bartlett Learning, LLC. www.jblearning.com Structures of the Periodontium and Their Functions The Gingiva Part of mucosa that surrounds cervical portions of teeth and covers alveolar Copyright © 2024 by Jones & Bartlett Learning, LLC. www.jblearning.com processes © Wolters Kluwer The Gingiva (cont.)  Contour and shape of gingival margin approximates scalloped curvature of cementoenamel junction (CEJ)  Position may be age dependent Copyright © 2024 by Jones & Bartlett Learning, LLC. www.jblearning.com  Attached by junctional epithelium  Composed of thin outer layer of epithelium and underlying layer of connective tissue The Gingiva (cont.)  Four anatomical areas:  Free gingiva, gingival sulcus, interdental gingiva, and attached gingiva  Function Copyright © 2024 by Jones & Bartlett Learning, LLC. www.jblearning.com  Protects underlying tooth-supporting structures of periodontium from oral environment The Gingiva (cont.)  Boundaries:  Gingival margin  Alveolar mucosa  Demarcations: Copyright © 2024 by Jones & Bartlett Learning, LLC. www.jblearning.com  Free gingival groove © Wolters Kluwer  Mucogingival junction Free Gingiva  Unattached portion surrounding tooth in CEJ region  Also called unattached gingiva or marginal gingiva Copyright © 2024 by Jones & Bartlett Learning, LLC. www.jblearning.com  Most coronal boundary of gingiva  Surrounds tooth in a turtleneck manner  Attaches by junctional epithelium Free Gingiva (cont.)  Fits closely around tooth, but not directly attached  Can slightly retract with periodontal probe  Forms soft-tissue lateral wall of gingival sulcus Copyright © 2024 by Jones & Bartlett Learning, LLC. www.jblearning.com  Free gingival margin  Thin, rounded edge where free gingiva meets tooth  Follows scalloped, curved contours of underlying CEJ Attached Gingiva  Continuous with free gingiva  Tightly bound to:  Underlying cementum on Copyright © 2024 by Jones & Bartlett Learning, LLC. www.jblearning.com cervical-third of root  Periosteum of alveolar bone © Wolters Kluwer Width of the Attached Gingiva  Widest in incisor and molar regions  Narrowest in premolar regions Copyright © 2024 by Jones & Bartlett Learning, LLC. www.jblearning.com  Not measured on palate © Wolters Kluwer Width of the Attached Gingiva (cont.)  Was once believed that a minimum 2-mm width of keratinized gingiva was necessary for periodontal health  Concept currently being revisited Copyright © 2024 by Jones & Bartlett Learning, LLC. www.jblearning.com  Amount of “necessary” keratinized tissue never established Color of the Attached Gingiva  Pale or light coral pink when healthy  May have physiologic pigmentation Copyright © 2024 by Jones & Bartlett Learning, LLC. www.jblearning.com  Caused by increased Courtesy of Elizabeth Carr, University of Mississippi Medical Center, Jackson, MS. melanin production Courtesy of Elizabeth Carr, University of Mississippi Medical Center, Jackson, MS. Texture of the Attached Gingiva  May exhibit stippling on healthy attached and interdental gingiva  Not always present Copyright © 2024 by Jones & Bartlett Learning, LLC. www.jblearning.com  Absent in most periodontally healthy adults © Wolters Kluwer Function of the Attached Gingiva  Allows gingival tissue to withstand mechanical forces created during chewing, speaking, and toothbrushing  Prevents free gingiva from being pulled apically from tooth when tension is applied to alveolar mucosa Copyright © 2024 by Jones & Bartlett Learning, LLC. www.jblearning.com Interdental Gingiva Portion of gingiva that fills interdental embrasure between two adjacent teeth Copyright © 2024 by Jones & Bartlett Learning, LLC. www.jblearning.com apical to contact area © Wolters Kluwer Interdental Gingiva (cont.)  Consists of facial papilla and lingual papilla  Interdental col  Depression apical to contact area of adjacent teeth that connects facial and lingual papillae Copyright © 2024 by Jones & Bartlett Learning, LLC. www.jblearning.com  The col is absent if adjacent teeth are not in contact with each other.  Function  Prevents food from packing between teeth when chewing  Copyright © 2024 by Jones & Bartlett Learning, LLC. www.jblearning.com Interdental Col © Wolters Kluwer Gingival Sulcus V-shaped shallow space between free gingiva and tooth surface Copyright © 2024 by Jones & Bartlett Learning, LLC. www.jblearning.com © Wolters Kluwer Gingival Sulcus (cont.)  Encircles neck of tooth  1 to 3 mm deep when clinically healthy  Measured with periodontal probe Copyright © 2024 by Jones & Bartlett Learning, LLC. www.jblearning.com  Base interfaces with most coronal portion of junctional epithelium  Junctional epithelium, epithelial attachment, the base of the sulcus: All terminology that means the same thing. Gingival Crevicular Fluid  Also called gingival sulcular fluid  Seeps from underlying connective tissue  Little to none in the healthy sulcus Copyright © 2024 by Jones & Bartlett Learning, LLC. www.jblearning.com  Flow increases in response to gingival stimulation  Greatly increases with inflammation  Measured with filter strip Periodontal Ligament (PDL) Network of soft connective tissue fibers that attach root of tooth to bony walls Copyright © 2024 by Jones & Bartlett Learning, LLC. www.jblearning.com of tooth socket © Wolters Kluwer Periodontal Ligament (cont.)  Primarily composed of dense fibrous connective tissue  Fibers attach to root cementum and alveolar bone  Serves to:  Connect tooth to alveolar process Copyright © 2024 by Jones & Bartlett Learning, LLC. www.jblearning.com  Support tooth in socket  Absorb mechanical loads placed on tooth Functions of the Periodontal Ligament  Suspends and maintains tooth in socket  Nerve endings relay sensory information  Blood vessels provide oxygen and nutrients Copyright © 2024 by Jones & Bartlett Learning, LLC. www.jblearning.com  Certain components build and maintain attachment apparatus and may aid periodontal regeneration  Can remodel alveolar bone in response to pressure Cementum Thin layer of hard, mineralized tissue that covers surface of root Overlies dentin Softer than dentin or enamel Copyright © 2024 by Jones & Bartlett Learning, LLC. www.jblearning.com 55% organic ( collagen matrix proteins 45% inorganic (calcium, hydroxyapatite, trace elements) © Wolters Kluwer Cementum (cont.)  More resistant to resorption( loss of substance) than bone  Makes orthodontic treatment possible  Bone resorption & not root resorption Copyright © 2024 by Jones & Bartlett Learning, LLC. www.jblearning.com  Undergoes continuous resorption and repair throughout the lifetime of tooth  Becomes thicker with age  Two types: cellular and acellular  Copyright © 2024 by Jones & Bartlett Learning, LLC. www.jblearning.com Cementum (cont.) Cementum (cont.)  Receives nutrients from PDL  Relatively permeable to:  Bacteria: With periodontal disease bacteria has been shown to invade cementum. Copyright © 2024 by Jones & Bartlett Learning, LLC. www.jblearning.com Functions of Cementum in the Periodontium  Gives attachment to PDL collagen fibers  Via terminal endings known as Sharpey’s fibers  The outer layer protects the underlying dentin  Seals ends of open dentinal tubules Copyright © 2024 by Jones & Bartlett Learning, LLC. www.jblearning.com  Compensates for tooth wear at occlusal or incisal surface due to attrition  Allows the tooth to maintain it’s length Alveolar Bone (Alveolar Process) Bone of upper or lower jaw that surrounds and supports roots of teeth Copyright © 2024 by Jones & Bartlett Learning, LLC. www.jblearning.com © Wolters Kluwer Alveolar Bone (cont.)  Mineralized connective tissue  60% inorganic, 25% organic, 15% water  Existence dependent on presence of teeth  Resorbs when teeth are extracted Copyright © 2024 by Jones & Bartlett Learning, LLC. www.jblearning.com  Absent if teeth do not erupt  Forms bony sockets that support and protect roots  Copyright © 2024 by Jones & Bartlett Learning, LLC. www.jblearning.com © Wolters Kluwer Layers of the Alveolar Process © Wolters Kluwer Alveolar Bone Proper (Cribriform Plate)  Thin layer of bone lining socket surrounding root of tooth that contains:  Alveolus Copyright © 2024 by Jones & Bartlett Learning, LLC. www.jblearning.com  Foramina  Sharpey’s fibers Courtesy of Dr. Don Rolfs, Periodontal Foundations, Wenatchee, WA. Cortical Bone (Cortical Plate) Layer of compact bone that forms hard, outer wall of mandible and maxilla on facial and lingual aspects Surrounds alveolar bone proper and supports socket Buccal cortical bone Copyright © 2024 by Jones & Bartlett Learning, LLC. www.jblearning.com Thinner in incisor, canine, and premolar regions Thicker in molar regions Does not appear on the radiograph Only Cancellous bone and alveolar bone proper can be seen. Cortical Bone (Cortical Plate) (cont.)  Alveolar crest  Coronal-most portion of alveolar process  1 to 2 mm apical to CEJs Copyright © 2024 by Jones & Bartlett Learning, LLC. www.jblearning.com  From facial or lingual aspect, meets teeth in scalloped form that follows CEJ contours Courtesy of Dr. Don Rolfs, Periodontal Foundations, Wenatchee, WA. Cortical Bone (Cortical Plate) (cont.)  Cancellous bone (spongy bone)  Fills interior portion of alveolar process  Found mostly in interproximal areas  Higher proportion in maxilla than in mandible Copyright © 2024 by Jones & Bartlett Learning, LLC. www.jblearning.com  Periosteum  Layer of connective tissue covering outer surface of bone