DEH 103: Histology & Embryology
Chapters 11 & 12: Periodontal Ligament and Alveolar Process
Chapters 11 & 12: Periodontal Ligament and Alveolar Process
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Lernkarten
What does teh periodontium include?
- Cementum
- Alveolar bone
- Periodontal ligament
Where does the periodontium originate?
Mesencmal cells
These are groups of epithelial cells the become located near the cementum in the mature PDL after the disintegration of the ____ during the formation of the root.
- Epithelial rests of Malassez
- Heartwig's epitheilial root sheeth
What is the main type of cell in the PDL?
Fibroblast-clast
What are the componenets of the PDL?
- Blood vessels
- Endothelial vasular lining cells
- Odontoblasts/clasts
- Mesencymal cells
- Nerve supply
- Macrophages for defense
These are elastic fibers taht stretch and contract during mastication. Interface with collagen bundles to provude support.
Oxytalan fibers
This is the space located between the budles of principal fibers that carry the vascular, neural, and lymphatics. It helps maintain tooth vitality.
Interstitial space
Where does the blood supply for the PDL stem from?
Branches of the superior and inferior alveolar arteries
These collagen fibers function to hold the tooth firmly in the jaw. They are formed during cementum and bone and end in budles of periodntal ligament fibers.
Sharpey's fibers
What are 2 classifications of principle fibers and what are their subdivisions?
- Dentoalveolar fiber group: named accourding to their origina nd insertion in the dentoalveolar process.
- Alveolar crest
- Horizontal
- Oblique
- Apical
- Interradicular
- Gingival fiber group: support the gingiva.
- Transseptal
- Attached gingival
- Free gingival
- Circumferential
What are the 4 main functions of the PDL?
- Supportive: most important function. keeps teeth in the socket during masitcation.
- Maintenance or formative: all the fibroblasts/clasts and osteoblasts/clasts, and mesenchymal cells are located here.
- Sensory: receptors for nerve sensors of pressure and pain
- Nutritive: blood, nerve, and lymphatics are located here
The alveolar bone is ___% inorcanic, ____% organic and ____% water
- 60
- 25
- 15
The alveolar process is divided into?
- Alveolar bone proper
- Supporting alveolar bone
This is the alveolar process that is apical to the roots and forms the body of the maxilla and mandible.
Basal bone
This is compact of dense bone of the wall of the tooth socket; where the PDL fibers are located.
- Alveolar bone proper
- Lamina dura (radiographic PDL space)
- Bundle bone
The supporting bone is subdivided into?
- Cortical plate: outside wall of the mandible and maxilla
- Trabecular bone: the filling bone between the cortical bone.
This it the linig of a tooth socket.
Alveolus
The alveolar bone proper is also known as ___ because of the ____.
- Cribiform plate
- Volkmann's canals that pass from the alveolar bone into the periodontal ligmaent
- Bundle bone
- Sharpey's fibers are bundled here
This is the bone located in the interproximal area of teeth that is seen on radiographs.
- Alveolar crest
- Interdnetal septum
- Interdental bone
What is the height of the alveolar crest (on radiographs) in healty situations?
1-2 mm apical to the CEJ
This is bone loss in the coronal area of the root.
Dehiscence
This is bone loss in the apical area of the root. Occurs when teeth are in buccolingual version. Bone gets thin or is missing.
Fenestration
This is the functional unit of bone.
Osteons (harvesian systems)
Each osteon consists of concntric layers or _____ of compact bone tissue that surrounds the central canal or the _____. These canals are where teh blood anve nerves are located.
- Lamellae
- Haversain canal
These are small spaces in the bone where osteoclasts are located.
Lacuna
The haversian canals entend through the bone on the long axis and the volkmann's canals enter the canals at?
Right angles.
What can cause bone resprotion?
- Eruptive process
- Trauma from mallocllusion
- Periodontal disease
- Pressure produced during ortho
- Pressure produced by mesial drift
How does a tooth move?
- If PDL fibers are pulled and bone is grown.
- If PDL fibers are compressed bone is broken downq
This occurs when the tooth movement is too rapid and vascularity is excluded.
Hyalinization
How wide is the PDL (lamina dura) space?
0.15 - 0.38 mm
If there is a decrease in the function of a tooth there will be a ____ in the PDL.
Decrease width
