Gingival Fibers and PDL Flashcards
what are the functions of the gingival fiber ligament
-stabilizes the gingiva by providing rigidity and density to the marginal gingiva
- acts as a periosteum for the interproximal crestal alveolar bone
- provide one half of the biological width
-acts as a protective barrier for the crestal alveolar bone against the spread of gingival inflammation
-inhibit the apical migration of the junctional epithelium
what are the GFL fiber groups
dentogingival, dentoperiosteal, alveologingival ,circular, transseptal, semicricular, transgingival
how many semicircular GFL fibers groups, transspetal, and transginigval are there
9,7, and 3
what is the function of transseptal fiber groups
resist tooth separation
what is the function of dentogingival fiber groups
resists gingival displacement
what is the function of alveogingival fiber groups
resist gingival displacement
what is the function of circumferential fiber groups
resist gingival displacement
what is the function of semicircular fiber groups
resist gingival displacement and tooth separation
what is biological width
area of junctional epithelium and gingival fiber ligaments attached to the root of a tooth
how big is the junctional epithelium, gingival fiber ligaments
0.98 - junctional epithelium
1.02 - gingival fiber ligaments
where is the biological width located
extends from crest of gingival to crest of alveolar bone
what happens if the biological width is violated
chronic inflammation will occur and result in induced loss of supporting alveolar bone with formation of a diseased periodontal pocket
when does violation of biological width occur
with incorrect placement of crowns
what are the symptoms of violation of biological wdith
itchy and bleeding gums, chronic irritation/inflammation
how do you fix violation of biological width
crown lengthening, change height of alveolar crest to keep 2 mm separation
what does the periodontal ligament contain
co-fibers of collagen that interlock together
what are the functions of the peridodontal ligament
-supportive
- regeneration
-nutritional
-sensory
-protective
what are the dental follicle zones and what do they give rise to
-peripheral zone - alveolar bone proper
- intermediate zone - PDL
- proximal zone - cementoblasts
what is the PDL derived from
neural crest (ectomesenchymal cells) in the intermediate zone of the dental follicle
periodontal fibers form as ____
the tooth grows
what do PDL fiber groups do
contract and function in the eruption of the tooth
what are PDL fibers designed to resist
rotational/torque-like forces on the tooth
what are sharpey’s fibers
collagen fibers from the alveolar bone and cementum that embed into cementum
what cells are in the PDL
-fibroblasts
-osteoblasts
-cementoblasts
-macrophages
-undifferentiated mesenchymal cells
-endothelial cells
-epithelial cells
what do apical fibers do
resist vertical force
what do oblique fibers do
resists intrusive/masticatory force
what do horizontal fibers do
resist horizontal and tipping force
what do alveolar crest fibers do
resist vertical force
what do interradicular fibers do
resist vertical and lateral force
what is orthodontic relapse
after ortho treatment, retainers are given due to PDFs memory
what is done to limit orthodontic relapse from occurring
transseptal fibers and semicircular fibers are cut
what are interstital spaces
source of mesenchymal cells that can differentiate into cementoblasts, osteoblasts, and fibroblasts
what do cementoblasts do
regeneration and repair of cementum following injury
what do osteoblasts do
function in regeneration and repair of bone following disease or orthodontic therapy of alveolar bone
what do fibroblasts do
involved in collagen production and physiological collagen degradation
what is ankylosis
reparative response to injury
what happens in ankylosis
fusion of cementum with the alveolar bone without intervening the PDL
what happens in singificant injury in akylosis
cells responding are from the supporting alveolar bone, results in ankylosis and loss of PDL
what happens in slight injury in ankylosis
cells responding are from the PDL will regenerate all tissues involved and PDL will be restored
what are the steps in wound healing
-undifferentiated cells migrate into the area as macrophages and PMNs cause inflammatory response and remove damaged tissues
- fibroblasts and or osteoblasts replace the damaged tissue
- a mast cell response is usually present in which heparin and histamine are released. this inflammatory response helps the necessary cells reach their target
what is guided tissue regeneration
surgical technique of regenerating the periodontal attachment apparatus on periodontally involved teeth which uses the differentiation of mesenchymal cells in the interstitial spaces of the PDL and narrow spaces of the adjacent alveolar bone
what does guided tissue regeneration use
a membrane to help block epithelial cells from growing down into the defect
what are epithelial rests of malassez
remains of hertwigs rooth sheath, duct like apperance with unknown function
where are epithelial rests of malassez found
apical areas of adolescent teeth
when do lateral periodontal cysts occur
when rests of malassez are activated
is tx of lateral periodontal cysts necessary
yes
what are epithelial rests of serres
remains of the dental lamina
what is a gingival cyst derived from
odontogenic epithelium located in the CT of the gingiva
what are epithelial rests of serres thought to be connected to
gingival keratocyst/odontogenic keratocyst
what does orthodontic movement result from
compression of the PDL on the side of the root corresponding to the direction of movement
what happens to the PDL in direction of tooth movement
compression of the PDL results in loss of principle fiber orientation and resorption of adjacent bone. fibroblasts and osteoclasts eating things
what happens to the PDL in movement in the direction opposite tooth movement
stretching/tension of the PDL principle fibers, controlled tension results in bone apposition
-osteoblasts laying down bone
what is trauma from occlusion
extensive functional stresses placed on a tooth by an antagonist that exceeds the limits of physiological adaptation
what does trauma from occlusion result in
resportion of alveolar bone parallel to the long axis of the root
-a PDL that is wider than normal average width
-tooth mobility
what is the tx for trauma from occlusion
re-establishing occlusion by fixing crown
what is disuse atrophy from
a tooth with no occlusal antagonist
what does disuse atrophy result in
-significant decrease in density of bony trabeculae
- decreased width of PDL
- loss of orientation of the principle fibers of the PDL
- increased volume of the bone marrow spaces
what is an ameloblastoma
aggressive benign tumor derived from odontogenic epithelium that exhibits a radiolucent, multilocular radiographic appearance
