1. Tissues surrounding teeth
PERIODONTIUM
Includes structures and tissues that surround and support the teeth
Alveolar Process
Gingiva
Periodontal Ligament/Membrane
Cementum

2. Cementum Characteristics:
Covers root of tooth – forms a thin layer around the root
Has same density as bone
55% inorganic
Contains fibers that attach tooth to the alveolar bone

3. Cementum
Cementum is a tissue of the tooth and an important part of the supporting structure
Function: attachment of the tooth in its socket

4. Cementum Clinical concerns: May be exposed with recession of gingiva
Removal of some of cementum could expose dentin
Extreme sensitivity is experienced by patients with exposed cementum and dentin

5. Cementum Clinical concerns: Cemental spurs may form at C E J
Calculus is easy to remove, spurs are not
Hypercementosis – occurs at apex in response to trauma

6. Alveolar Bone Structure:
Bones in the maxilla and mandible are formed by osteoblasts
Extended areas of bone that hold the teeth are referred to as the alveolar process

7. Alveolar bone/process
Lamina dura – outside layer of bone surrounding the periodontal ligament
Lamina dura – ‘hard layer’ (like the crust of bread)
Cortical bone – compact or dense layer of bone

8. Alveolar bone/process
Cancellous bone – inner or central part of alveolar bone
Cancellous bones is also referred to as trabecular bone
Spongy or porous in appearance

9. Alveolar bone/process
Function:
Supports the tooth
Stabilizes the root

10. Alveolar bone Clinical concerns:
Periodontal disease can cause loss of bone
Bone is stimulated from chewing and speech – if teeth are removed this stimulation is lost and bone resorbs

11. Alveolar Process
Lamina dura, cortical, spongy

12. Periodontal Ligament Surrounds the root of the tooth
Composed of fibers, or ligaments, that support and suspend the tooth in the socket
Fibers are arranged in bundles
Forms a ‘shock-absorber’ for the tooth in the socket

13. Periodontal ligament Contains fibers for attachment
Contains nerves, blood vessels and lymph vessels

14. Periodontal ligament FUNCTIONS: Supportive – maintains tooth in socket
Sensory – nerves supply ‘sense of touch
Formative – fibroblasts, cementoblasts
Protective- cushion-like action from shock
Nutritive– blood vessels provide nutrients

15. Periodontal fiber groups
Alveolar crest fibers-extend from cervical area of tooth to alveolar crest
Horizontal group – run at right angles
Oblique group – slants into alveolar bone
Apical group – extend from apex
Interradicular –only in multi-rooted teeth
Transseptal – from one tooth to another

16. PDL Fibers

17. Periodontal fiber groups
Most important fibers:
Oblique – largest group – resist vertical (up and down) force
Work like shock absorbers
Transseptal or interdental – support interdental gingiva

18. Gingival fiber group
Found above the alveolar bone crest and below the epithelium
Dentogingival fibers
Circular ligament fibers
Alveologingival fibers
Dentoperiosteal fibers

19. Periodontal ligament Clinical considerations:
Occlusal trauma does not cause periodontal disease but can accelerate an existing condition
Chronic periodontal disease causes the fiber groups to become disorganized and lose attachment due to resorption

20. Gingiva Only portion of periodontium visible in oral cavity
Made up of epithelial tissue covered with mucosa
Surrounds cervix of tooth
Fills interproximal spaces

21. Gingiva
Free Gingiva – movable – fits snugly around the crown just above the cervix of tooth
Attached Gingiva – non-movable – extends from the base of the sulcus to the mucogingival junction
Attached directly to the cementum and alveolar process

22. Gingiva

23. Gingiva Characteristics of normal tissue:
1) adapts tightly to tooth and bone
2) firm and resistant
3) surrounds tooth in collar-like fashion
4) color varies from pink to coral
5) surface is stippled
Stippling – like surface of an orange

24. Gingiva Alveolar mucosa – appears thin and loosely attached
Attached gingiva – part that is stippled
Gingival sulcus – space between the unattached gingiva and the tooth
Normal depth is about 2 mm
Gingival papilla – interdental extension of free gingiva (between teeth)

25. Mucosa -- differences Masticatory mucosa – dense covering in the mouth
Withstands activity of mastication (chewing)
Covers gingiva and hard palate
Lining mucosa – covers the oral soft tissues that are not covered by masticatory mucosa
Covers insides of cheeks, soft palate, floor of mouth; tears and injures easily

26. Gingiva Clinical considerations:
Certain drugs can affect the gingiva and cause gingival hyperplasia, (over growth of tissue)
Tissue can become inflamed to fight infection – appearing swollen and red, bleeds easily, and looses its stippling

27. Gingival description
Healthy gingiva is pink and stippled on the attached portion.
Normal gingiva is firm and resilient; it follows the contour of the bone and fills the interproximal spaces, forming a sharp, knifelike triangular point at the contact area.

28. Gingival description
Attached gingiva adheres tightly to the bone and is pale, compared to the smooth shiny alveolar mucosa, which contains many blood vessels and thus appears more red in color.

29. Review: Periodontium – supporting structure of the tooth
– composed of:
Cementum
Periodontal ligament
Gingiva
Alveolar process

30. Review: Healthy gingiva: Fits tightly around tooth and bone
Surrounds like a collar
Color varies with ethnicity
Surface is stippled

31. Review:
Two types of gingiva:
Free gingiva
Attached gingiva

32. Review: Function of periodontal ligament
Most important function is supportive – maintains the tooth in the socket by fiber attachment

33. Trick or Treat