Anatomy of the Periodontium Part II #2 Flashcards
Junctional Epithelium attaches to _________.
Enamel
Biological width is the ______ and ________.
JE and CT
______ is capable of becoming JE.
Oral epithelium
What are the 4 main differences between JE and OE?
Size of cells (JE>OE because its more active)
Size of Intracellular space (JE>OE b/c cells are bigger)
# of desmosomes = JE
T or F, JE has many desmosomes.
False, it has very few.
What is passive eruption?
Where tooth continues to erupt causing apical movement of JE (till it is below the CEJ often) *No inherent loss of JE here though.
_______ occurs when JE migrates apically down root surface.
Attachment loss
What happens with necrosis of junctional epithelium?
JE cells die, and bone is exposed. There IS a actual loss of JE here, not just attachment loss.
What are the 4 main fibers of the gingival connective tissue-lamina propria?
- Collagen = most abundant
- Reticulin = numerous adjacent to basment membrane
- Oxytalan = mostly in PDL, run parallel to long axis of tooth and keep blood vessels open during chewing.
- Elastic = around blood vessels (keeps blood vessels from being squished during mastication)
What are the 4 types of Gingival fiber?
- Circular fibers = around the tooth
- Dentoginigval fibers = from supracrestal cementum to free gingiva.
- Dentoperiosteal fibers = run from supracrestal cementum into attached gingiva
- Trasseptal fibers = run from tooth to tooth.
What is the width of the PDL?
about 0.25mm
Describe the structure of the PDL…
Richly vascularized and cellular CT surrounding the roots and join the cementum and alveolar bone.
What are the 4 types of PDL fibers?
- alveolar crest fibers
- horizontal fibers
- oblique fibers
- apical fibers
What are the 7 cells of the PDL and what do they do?
- Fibroblasts = align along principal fibers
- Osteoblasts = line bone surface
- Cementoblasts = line cemental surface
- Osteoclasts = multi nucleated, crete ruffled surface of bone
- Nerve fibers
- Epithelial rest of Mallassez = remnants of the Hertwig’s epithelial root sheath.
- Epithelial cells
Cementum is similar to bone in composition except for……
- no blood vessels in cementum
- no lymph vessels
- no innervation
- no physiological resorption/remodeling
What are Intrinsic Cemental fibers?
Produced b cementoblasts
- composed of fibers oriented parallel to root.
What are Extrinsic Cemental fibers?
Sharpey’s fibers
- produced by PDL fibroblasts
What type of Cemental fibers are found coronal or middle portion of root?
Acellular, extrinsic fiber cementum
What type of Cemental fibers are found in apical third of the root and furcations?
Cellular, mixed stratified cementum
What type of Cemental fibers are found in resorption lacunae?
Cellular, Intrinsic fiber cementum
What happens to cementum throughout life?
Thickness increases
What is the thickness of cementum in the cervical (upper) portion of the root?
20-50 um
What is the thickness of cementum in the apical portion of the root?
150-250 um
What cells form alveolar bone?
Cells from dental follicle and other cells independent of tooth development
______ produce bone matrix consisting of collagen fibers, glycoproteins and proteoglycans.
Osteoblasts
______ undergoes mineralization by the deposition of minerals.
Osteoid
Describe blood supply to gingiva…..
Via supraperiosteal vessels that are terminal branches of buccal, mental, sublingual, facial……
Describe blood supply to PDL…
Dental A.
Sup. and Inf. alveolar A
Intra-septal A
Rami perforantes A
Describe the nerves of the Periodontium…
End branches of the trigeminal nerve:
- infraorbital
- sublingual
- mental
- Buccal
- PSD
- Greater palatal
- long sphenopalatine
