Normal Periodontum Pt. 2 Flashcards
composed of a complex vascular and highly cellular connective tissue that surrounds the tooth root and connects it to the inner wall of the alveolar bone. It is continuous with the connective tissue of the gingiva, and it communicates with the marrow spaces through vascular channels in the bone.
Periodontal Ligament
What is the average width of the PDL?
0.2mm
Explain the trend in the periodontal space with use and disuse?
PDL size is diminished around teetht that are not in function or unerupted
PDL siz is increased in that are subject to hyperfuncion
WHat are the most important elements in the PDL?
Principle fibers
collagenous and arranged in bundles and which follow a wavy course when viewed in longitudinal section of the PDL
Principle Fibers
Where do the terminal ends of the PDL principle fivers insert?
What are their names?
They insert into the cementum and bone.
SHARPEY FIBERS
The principal fiber bundles consist of individual fibers that form a continuous ___ ___ between tooth and bone.
Anastamosing Network
The amount of collagen ina tissue can be determined by what?
its hydroxyproline content.
High= lots of collagen
is a protein that is composed of different amino acids, the most important of which are glycine, proline, hydroxylysine, and hydroxyproline
Collage
What is collagen responsible for?
maintenance of the** framework** and the toneof tissue
WHere does collagen synthesis occur?
inside the fibroblasts
Tropocollagen molecues agregate into what that are packed together to form fibrils?
Microfibrils-> fibrils
WHat 4 cells synthesize collagen?
- Fibroblast
- Chondrobkast
- Osteoblasts
- Odontoblast
WHat type of collagen mainly makes up principle fibers?
Type 1
whereas reticular fibers are composed of what kind of collagen
Collagen 3
WHat collagen is found in the basal lamina?
Collage 4 (IV)
What are the 6 fiber groups of the PDL?
- transseptal
- alveolar crest
- horizontal
- oblique
- apical
- Interradicular fibers
Tall and handsome only at Ibiza
What fiber group?
fibers radiate in an irregular pattern from the cementum to the bone
Found only on the apical region of the socket
Apical Group
WHat group of PDL fibers is found only on the apical region of the socket?
Apical group
What fiber group?
Right angles to the long axis of the tooth
Horizonal Group
What fIber group?
The largest group
Extends from the cementum in a coronal direction obliquely to the alveolar bone.
Oblique fibers
extend obliquely from the cementum just beneath the junctional epithelium to the alveolar crest
Alveolar Crest Fibers
What fiber group?
Extend over the alveolar bone crest and are embedded in the cementum of adjacent teeth where they form an interdental ligament
Transseptal Fibers
If there is adjacent tooth loss, which principle fiber will be lost?
Transseptal fibers
WHat fiber group?
Fan out from the cementum to the tooth in the furcation area of multirooted teeth
Interradicular FIbers
WHat are the 4 types of cells in the PDL?
- Fibroblasts
- Cementoblasts
- Osteoblasts
- Epitehlias rest cells + immune system cells
WHat are the most common cells in the PDL?
Fibroblasts
What kind of cells in PDL?
ovoid or elongated cells oriented along the principal fibers, and they exhibit pseudopodia-like processes
Fibroblasts
What are the two main functions of fibroblasts?
- Synthesize collagen
- Phagocytose old collagen fibers and degrade them via enzyme hydrolysis
Collagen turnover is regulated by fibroblasts
What 4 cells are also seen in the cemental and osseous surfaces of the PDL.
- Cementoblasts
- Osteoblasts
- Odontoblasts
- Osteoclasts
What PDL cell?
- Uninucleated cells
- Cuboidal in shape
- Synthesize bone proteins
- Synthesize alkaline phosphatase (used for mineralization of bone)
Osteoblasts
What PDL cell?
- Observed during phases of active cementum deposition
- Oval to cuboidal in shape
- Large nuclei
- After some cementum has been deposited, mineralization begins with the help of calcium and phosphate ions
Cementoblasts
WHat PDL Cell
form a latticework in the periodontal ligament and appear as either isolated clusters of cells or interlacing strands
Epithelial Rests of Malassez
considered remnants of the Hertwig root sheath, which disintegrates during root development.
Epithelial rests of Malassez
epithelial rests proliferate when stimulated and they participate in the formation of what?
periapical cysts and lateral root cysts.
What cells work immune defense in the PDL?
- neutrophiles
- Lymphocytes
- macrophages
- mast cells
- eosinophills
WHat is shown this x-raY?
Lateral root cyst; causes by Epithelial rest cells
The PDL also contains a large proportion of ____ ____ that fills the spaces between fibers and cells.
- Amorphous gel-like substance surrounding the cells
- Transparent, colorless, and fills the spaces between fibers and cells
- Fibers interspersed in
Groud Substanes
clear
The two main components of ground subatance are?
- glycosaminoglycan
- Glycoprotiens
What is the water content in ground substance?
70%
What part of ground substance?
participate in several biologic functions, including cell adhesion, cell–cell and cell–matrix interactions, binding to various growth factors as coreceptors, and cell repair.
Cell surface Proteoglycans
A glycosaminoglycans
WHat are 5 physical functions of the PDL?
- Provides soft tissue casing to protect vessles and nerves.
- Transmission of occlusal force to bone
- Attach teeth to bone
- Maintain gingival tissue inproper relationshipwith teeth
- SHock absorbtion
Cells of the PDL participate in the formation and resorption of cementum and bone, which occur when?
- Physiologic tooth movment
- Orthodontic movment
- accomondation of periodontum to occlusal forces
- repair of injury
The PDL is supplied with ____ which can transmit **tactile, pressure, and pain sensations **via the trigeminal pathways
SENSORY NERVE FIBERS
the ability of periodontal ligament cells to synthesize and secrete a wide range of regulatory molecules is an essential component of tissue remodeling and ___ ____ ____
PDL homeostasis.
the calcified, avascular mesenchymal tissue that forms the outer covering of the anatomic root.
Cementum