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UKCD Histo Perio Lig
learning objective answers for periodontal ligament
Question | Answer |
---|---|
What is the function of the periodontal ligament, and more specifically the principal fiber bundles? | To anchor the tooth within the bony socket and allow for limited movement in response to occlusal pressure. |
Of what is the PDL composed? | Cell (fibroblasts and other CT cells), fibers (Type I collagen predominates), and ground substance (proteoglycans and glycoproteins). |
The collagen fiber bundles of the PDL can be classified into two main groups. Name them and state the feature their name is indicative of. | Gingival fiber group – those fibers that do not insert into bone; and dentoalveolar fiber groups – those fibers that insert into alveolar bone. |
List three groups of gingival fibers of the PDL. | Gingival, circumferential and transseptal. |
Between which structures do these gingival fibers extend? | Gingival from cementum into gingiva; circumferential from cementum into lamina propria after extending around root horizontally; transseptal – from cementum of one tooth across the interdental septum to insert into the cementum of the adjacent tooth. |
What is the function of the gingival fibers of the PDL? | Gingival (free and attached) fibers of the PDL resist gingival displacement during occlusal movement. |
List five groups of dentoalveolar fibers in the PDL. | Alveolar crest, horizontal, oblique, (peri)apical and interradicular fibers. |
What is the function of the dentoalveolar fibers of the PDL? | They primarily resist vertical movement during occlusion. |
What structural/functional unit is formed by the transseptal fibers? | The dental arch. |
Do the blood vessels supply the pDL anastomose? | Yes. |
If the blood vessles that supply the PDL anastomose with vessel from what structures? | They arise as branches from the arteries entering the apical foramen and anastomose with branches from the alveolar bone via its cribriform nature. |
What types of nerves are found within the PDL and what is their function? | Autonomic – controlling blood vessel diameter; afferent – sensory via free (unmyelinated) nerve endings (pain sensation) as well as encapsulated nerve endings (pressure). |
Between which structures do alveolar crest gingival fibers extend? | cementum into the alveolar crest (angled upward) |
Between which structures do horizontal gingival fibers extend? | cementum of cervical 1/3 of tooth into alveolar bone of socket (angled horizontally) |
Between which structures do oblique gingival fibers extend? | cementum of apical 2/3’s of the tooth into alveolar bone (angled inferiorly) |
Between which structures do (peri)apical gingival fibers extend? | radiate from surrounding the apical foramen down to alveolar bone |
Between which structures do interradicular gingival fibers extend? | from cementum of root bifurcation into the apical region of the interradicular septum. |