PDL

Question 1

periodontium contains

Answer 1

gingiva
pdl
cementum
alveolar bone

Question 2

pdl is what kind of CT

Answer 2

soft specialized CT

Question 3

pdl connects between 2 hard tissues

Answer 3

cementum and alveolar bone

Question 4

what’s the space where pdl lies

Answer 4

periodontal space

Question 5

pdl is continuous with the pulp through 2 things

Answer 5

accessory canals and apical canals

Question 6

pdl has other names

Answer 6

gomphosis
desmodont
pericementum
dental periosteum
periodontal memebrane

Question 7

pdl width

Answer 7

0.15-0.38mm (0.2 mm approx.)

Question 8

thicker

Answer 8

functioning than non functioning teeth

areas of tension slightly

in alveolar crest

Question 9

thinnest

Answer 9

middle third of root giving it an hour glass appearance

thinner in embedded teeth and in compressed areas during force

thinner in permanent teeth

Question 10

age

Answer 10

as we age the width decreases due to deposition of cementum

young adults: 0.21mm
adults: 0.18 mm
old: 0.15mm

Question 11

xray

Answer 11

appears radiolucent between lamina dura( compact bone lining socket) which is radiopaque and cementum also radiopaque

Question 12

when does the pdl develop

Answer 12

ectomesenchymal cells (from neural crest origin) condense to form the dental papilla and dental sac (follicle).

then the HERS induces the ectomesenchymal cells of the dental papilla to differentiate into odontoblasts, which secrete predentin (that later becomes dentin).

after that HERS degenerates, allowing the ectomesenchymal cells of the dental sac to differentiate as follows:

The inner layer becomes cementoblasts → form cementum

The middle layer becomes fibroblasts → form the periodontal ligament (PDL)

The outer layer becomes osteoblasts → form alveolar bone

Question 13

how do the fibers go from unorganized to organized

Answer 13

initially the pdl fibers are unorganized going from cementum to bone later as fibroblast secrete collagen organizing fibers into strong organized one