Lecture 1 Periodontium: Tooth-Supporting Structures PDF

Lecture 1 Periodontium: The Tooth- Supporting Structures Chapter 1 Instructor: Ms. Cindy Yeon Hee Lee RDH, BSc, Cert. Adult Ed. Copyright © 2019 Wolters Kluwer All Rights Reserved 1 Copyright © 2014 Wolters Kluwer All Ri...

Lecture 1 Periodontium: The Tooth- Supporting Structures Chapter 1 Instructor: Ms. Cindy Yeon Hee Lee RDH, BSc, Cert. Adult Ed. Copyright © 2019 Wolters Kluwer All Rights Reserved 1 Copyright © 2014 Wolters Kluwer All Rights Reserved Periodontium Functional system of tissues that surrounds teeth and attaches them to the jawbone: Peri = around and odontos = tooth Also referred to a “supporting tissues of teeth” or “attachment apparatus”. Copyright © 2019 Wolters Kluwer All Rights Reserved 2 Tissues Comprising Periodontium Copyright © 2019 Wolters Kluwer All Rights Reserved 3 Healthy Periodontium Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins Copyright © 2019 Wolters Kluwer All Rights Reserved 4 THE GINGIVA Copyright © 2019 Wolters Kluwer All Rights Reserved 5 Gingiva The part of mucosa that surrounds cervical portions of teeth and covers alveolar process: Located coronal to CEJ of each tooth. Attached by specialized epithelial tissue: ‒ (which makes up the junctional epithelium) Composed of thin outer layer of epithelium and underlying layer of connective tissue. Function: protects underlying tooth-supporting structures of periodontium from oral environment: – Does so through defense mechanisms such as saliva and immune system. Copyright © 2019 Wolters Kluwer All Rights Reserved 6 Gingiva Boundaries: – Upper edge (coronal) is called gingival margin. – Lower edge (apical) is alveolar mucosa which is dark red tissue. Copyright © 2019 Wolters Kluwer All Rights Reserved 7  Gingiva Demarcations: – Free gingival groove is a shallow linear depression separating free and attached gingiva (may be hard to see with the naked eye) – Mucogingival junction is where the pink attached gingiva meets the red alveolar mucosa (clinically visible) Copyright © 2019 Wolters Kluwer All Rights Reserved 8 Gingiva: Four Anatomical Areas of Gingiva 1. Free Gingiva 2. Attached Gingiva 3. Interdental Gingiva 4. Gingival Sulcus Copyright © 2019 Wolters Kluwer All Rights Reserved 9 Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins  Free Gingiva Unattached portion that surrounds a tooth in the region of CEJ. Also referred to as “unattached gingiva” or “marginal gingiva” Copyright © 2019 Wolters Kluwer All Rights Reserved 10 Free Gingiva Located coronal to (above) CEJ. Surrounds the tooth like a turtleneck. Fits closely around the tooth but is not directly attached. Attached by the junctional epithelium. Forms soft tissue lateral wall of the gingival sulcus. Copyright © 2019 Wolters Kluwer All Rights Reserved 11  Free Gingiva May be gently retracted with a periodontal probe. Meets the tooth in a thin rounded edge called gingival margin. Gingival margin follows tooth contour creating a scalloped outline. Copyright © 2019 Wolters Kluwer All Rights Reserved 12  Attached Gingiva The part of the gingiva that is tightly bound to the underlying cementum (continuous with the free gingiva). Found on the cervical-third of the root and on the periosteum of alveolar bone. Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins Copyright © 2019 Wolters Kluwer All Rights Reserved 13 Attached Gingiva (cont.) Located between free gingiva and alveolar mucosa. Widest in the incisor and molar regions. Narrowest in premolar regions. Not measured on palate due to indeterminate ending of attached gingiva and beginning of palatal mucosa. Copyright © 2019 Wolters Kluwer All Rights Reserved 14 Gingival Tissue of the Palate Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins Copyright © 2019 Wolters Kluwer All Rights Reserved 15  Attached Gingiva (cont.) The color, when healthy, will appear pale or light coral pink. May be pigmented (physiologic pigmentation): – More frequent in dark-skinned individuals – Pigmented areas appear light brown to black – Due to increased production of melanin from melanocytes. Copyright © 2019 Wolters Kluwer All Rights Reserved 16 Attached Gingiva (cont.) If healthy, may have a dimpled appearance (stippled like an orange peel). – Seen only on attached and interdental gingiva. – Not seen on marginal gingiva. – Presence varies greatly from one individual to the next. – Stippling provides mechanical reinforcement. Copyright © 2019 Wolters Kluwer All Rights Reserved 17 Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins  Rete ridges Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins Connective tissue papillae Copyright © 2019 Wolters Kluwer All Rights Reserved 18 Attached Gingiva (cont.) Purpose of attached gingiva is to allow tissue to withstand forces during chewing, speaking and toothbrushing. Prevents free gingiva from being pulled apically from the tooth when tension is applied to alveolar mucosa. Copyright © 2019 Wolters Kluwer All Rights Reserved 19 Interdental Gingiva Portion of gingiva that fills the interdental space (embrasure) between 2 adjacent teeth just below the contact area. The interdental gingiva prevents food from becoming packed between teeth during chewing. Copyright © 2019 Wolters Kluwer All Rights Reserved 20 Interdental Gingiva (cont.) Consists of 2 interdental papillae: – Facial papilla – Lingual papilla Lateral border and tip formed by free gingiva of adjacent teeth. Center is formed by attached gingiva Copyright © 2019 Wolters Kluwer All Rights Reserved 21 Interdental Gingiva (cont.) Gingival col is a valley-like depression apical to the contact area of 2 adjacent teeth that connects facial and lingual papillae. The col will not be present if there is a large space between 2 teeth or there is notable gingival recession Copyright © 2019 Wolters Kluwer All Rights Reserved 22  Gingival Sulcus The V-shaped shallow space between free gingiva and tooth surface. Measured by a periodontal probe, a healthy sulcus measures 1-3 mm. The base of the sulcus is formed by junctional epithelium. Copyright © 2019 Wolters Kluwer All Rights Reserved 23 Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins Gingival Sulcus (cont.) Gingival crevicular fluid (GCF) seeps from underlying connective tissue into the sulcular space. There is little to none in a healthy sulcus. Flow increases in presence of bacterial plaque, toothbrushing and chewing. Flow is greatly increased in unhealthy gingiva. Copyright © 2019 Wolters Kluwer All Rights Reserved 24  PERIODONTAL LIGAMENT (PDL) and ROOT CEMENTUM Copyright © 2019 Wolters Kluwer All Rights Reserved 25 Periodontal Ligament (PDL) Layer of connective tissue that covers the root of the tooth and attaches it to the bone of the tooth socket. Composed of dense fibrous tissue. Fibers attach on one side to the cementum and alveolar bone in the socket on the other side. Copyright © 2019 Wolters Kluwer All Rights Reserved 26  Periodontal Ligament (cont.) Five functions: 1. Supportive: to maintain tooth in socket. 2. Sensory: provides feelings like pressure and pain. 3. Nutritive: by providing nutrients to cementum and bone. 4. Formative: by providing cementoblasts and osteoblasts. 5. Remodeling: of alveolar bone in response to pressure. Copyright © 2019 Wolters Kluwer All Rights Reserved 27  Root Cementum Thin layer of hard, mineralized connective tissue that covers the surface of the root. Attached to dentin but is softer than either dentin or enamel. Comprised of organic and inorganic substances. Copyright © 2019 Wolters Kluwer All Rights Reserved 28 Root Cementum (cont.) More resistant to resorption than bone making it possible for movement during orthodontic treatment. Continually resorbs and repairs during the lifetime of a tooth and becomes thicker with age. Dyes and bacteria can penetrate and invade. Copyright © 2019 Wolters Kluwer All Rights Reserved 29 Root Cementum (cont.) Functions: Primary function is for periodontal ligament attachment: ‒ Sharpey’s fibers are the terminal endings of periodontal ligaments attached to cementum. Seals off open dentinal tubules. Compensates for occlusal attrition to maintain tooth length: – However, excess deposit in apical third of root may result in hypercementosis which may obstruct apical foramen. – Hypercementosis appears radiopaque on an x- ray. Copyright © 2019 Wolters Kluwer All Rights Reserved 30 HYPERCEMENTOSIS Copyright © 2019 Wolters Kluwer All Rights Reserved 31 ALVEOLAR BONE Copyright © 2019 Wolters Kluwer All Rights Reserved 32  Alveolar Bone Mineralized connective tissue that forms bones of the upper and lower jaw to support roots of teeth. Forms bony sockets that provide support to roots of teeth. Existence is dependent on presence of teeth: – If teeth are extracted, alveolar bone will resorb with time. – If teeth do not erupt, alveolar bone does not develop. Copyright © 2019 Wolters Kluwer All Rights Reserved 33 Copyright © 2019 Wolters Kluwer All Rights Reserved 34 Alveolar Bone (cont.) Comprised of 3 layers of hard tissue covered by a layer of connective tissue: 1. Alveolar bone proper (aka cribriform plate) is a thin layer lining the socket: – Alveolus is the bony socket that houses the tooth. – Foramina (holes) allow blood vessels to connect cancellous bone to periodontal ligament (hence cribriform). – Sharpey’s fibers are embedded in alveolar bone proper. Copyright © 2019 Wolters Kluwer All Rights Reserved 35  Alveolar Bone Proper Copyright © 2011 Wolters Kluwer Health | Lippincott Willias & Wilkins Copyright © 2019 Wolters Kluwer All Rights Reserved 36 Alveolar Bone (cont.) 2. Cortical Bone (aka compact bone) is a layer of compact bone that forms the outer wall on facial and lingual surfaces: Alveolar crest (“peak of the mountain”) is the coronal-most portion of the alveolar process. Copyright © 2019 Wolters Kluwer All Rights Reserved 37 Alveolar Bone (cont.) 3. Cancellous bone (aka spongy bone) that fills the interior portion of the alveolar process and is found mostly in the interproximal areas. Copyright © 2019 Wolters Kluwer All Rights Reserved 38  Alveolar Bone (cont.) Periosteum is a layer of connective tissue that covers the outer surface of bone. Copyright © 2019 Wolters Kluwer All Rights Reserved 39 References: Jill S. Gehrig, Daniel E. Shin, Donald E. Willmann. Foundations of Periodontics for the Dental Hygienist. 5th edition. Lippincott, Williams & Wilkins, 2019. ISBN: 978-1-4963-8402-7. Fehrenbach, M.J., Popowics, T, Illustrated Dental Embryology, Histology, and Anatomy, 5th Ed., Elsevier Inc., Maryland Heights, Missouri, 2019. Google images. Copyright © 2019 Wolters Kluwer All Rights Reserved 40