PDL & cementum

Question 1

What does the PDL do in regards to the tooth?

Answer 1

thin sheet of fibrous CT located between the root of the tooth and its bony socket and connects to the tooth and the bony wall of the tooth sokcet

Question 2

Cementoblast form ____

Answer 2

cementum

Question 3

Osteoblasts form _____

Answer 3

bone

Question 4

what are the epithelial rests of lamassez

Answer 4

remnants of hertwig’s epithelial root sheath.

Question 5

what is the largest component of the PDL

Answer 5

fiber bundles

Question 6

true/false: The PDL has a rich supply of nerves, lymph and blood vessels, blood cells, and endothelial cells.

Answer 6

true

Question 7

where is the PDL thickest and thinnest?

Answer 7

thickest at the CEJ and apex and thinner in between

Question 8

name 5 functions of the PDL

Answer 8

supportive, sensory, nutritional, formative, and resorptive

Question 9

___ is the major function of the PDL and suspends the tooth in the socket

Answer 9

supportive

Question 10

_____ nerve fibers transmit pressure and pain for the PDL

Answer 10

sensory

Question 11

____ contains cementoblasts and osteoblasts in the PDL

Answer 11

formative

Question 12

____ occurs in response to severe pressue

Answer 12

resorptive

Question 13

5 principle fiber bundles of the PDL

Answer 13

1. alveolar crest
2. horizontal
3. oblique
4. apical
5. interradicular

Question 14

what fiber bundle group of the PDL resists horizontal movements, and extends from the cervical cementum and runs downward to the alveolar crest

Answer 14

alveolar crest group

Question 15

what fiber bundle group of the PDL extends from the cementum to the bone at right angles and resists horizontal pressure against the crown of the tooth

Answer 15

horizontal group

Question 16

what fiber bundle group of the PDL extends from the cementum to the bone in a diagonal direction. This group is the most numerous and resits vertical pressures that threaten to drive the root into the socket

Answer 16

oblique group

Question 17

which fiber bundle group of the PDL extends from the apex of the tooth to the bone and secures the tooth in its socket and resists forces that might lift the tooth out of the socket

Answer 17

apical group

Question 18

what fiber bundle group of the PDL is seen only in multirooted teeth and extends from the cementum in the furcation are of the tooth to the alveolar bone to help stabalize the tooth

Answer 18

interradicular group

Question 19

what are sharpey’s fibers?

Answer 19

ends of the PDL fibers that are embedded at 90 degrees in the cementum and alveolar bone.

Question 20

name 4 characteristics of cementum

color, location, resistance, doesn’t contain

Answer 20

light yellow in color
overlies and is attached to the dentin of the root
more resistant to resorption than bone which is why its possible to move teeth
does not have blood, nerve, or lymph supply because it gets its nutrients from the PDL

Question 21

3 functions of cementum

Answer 21

1. anchors the PDL to the tooth
2. protects the dentin and seals in the dentin tubules
3. cementum formation compensates for tooth wear

Question 22

cementum is a calcified layer of ______ that covers the root of the tooth

Answer 22

connective tissue

Question 23

What are two major components of cementum and their characteristics?

Answer 23

1. organic matrix: densly packed collagen fibers help together by the gel-like extracellular ground substance
2. mineralized: hydroxyapatite crystals that contains no blood vessels or nerves

Question 24

2 types of cementum with their location, components found in it, thickness range

Answer 24

1. acellular cementum: contains no cementocytes, first to form, covers the cervical third of tooth, cannot reproduce more once lost, 30-60 microns thick, and sharpeys fibers make up most of the acellular cementum
2. cellular cementum: contains cementocytes, formed after tooth has erupted, less calcified, 150-200 microns thick, sharpeys fibers amount is small

Question 25

what are the two parts to the alveolar bone

Answer 25

alveolar proper and alveolar supporting

Question 26

alveolar bone surrounds ___ and provides attachment for ____

Answer 26

surrounds the rooth

attachment for the PDL

Question 27

____ contains small holes for fibers and blood vessels

Answer 27

cribiform plate

Question 28

____ is seen on radiographs as a white line continuour with the crestal bone

Answer 28

lamina dura

Question 29

____ fiber bundles of PDL are inserted at 90 degrees

Answer 29

bundle bone

Question 30

where is the supporting alveolar bone located

Answer 30

surrounds the alveolar bone proper and gives support to the socket

Question 31

___ bone is found on the facial and lingual surfaces of the alveolar process and won’t show up on a radiograph

Answer 31

compact bone

Question 32

____ bone lies between the alveolar proper and the cortical bone

Answer 32

cancellous bone

Question 33

_____bone is located on the F & L surfaces of roots

Answer 33

redicular

Question 34

___ bone is located between the roots of multi-rooted teeth

Answer 34

interradicular

Question 35

T/F: The interproximal bone is not higher than facial and lingual bone

Answer 35

False

Question 36

most common dehiscence (which teeth) & what is it

Answer 36

maxillary canines

cleft like absence of cortical plate

Question 37

Bone liability

Answer 37

least stable, in constant change, formation is continuous

Question 38

what is hyperfunction?

Answer 38

occlusal trauma; bone may thicken on F & L cortical plates, size & number of trabeculae increase

Question 39

what is hypofunction?

Answer 39

tooth not in function or occlusion; bone resorbs, size & number of trabeculae decrease

Question 40

Does bone have blood vessels and nerves?

Answer 40

yes