Njds: Histology- Alveolar Bone And Pdl

Front 1

What is alveolar bone?

Back 1

The osseous tissue of the maxilla and mandible that surrounds and supports teeth

Front 2

What is alveolar bone derived from and when is it formed?

Back 2

Derived from the dental follicle and it is formed during cementogenesis

Front 3

What structure is composed of alveolar bone?

Back 3

Alveolar process

Front 4

What does the alveolar process consist of?

Back 4

Outer cortical plate, central spongy bone, and bone lining the tooth socket

Front 5

What is bundle bone?

Back 5

The bone into which the collagen bundles of the PDL insert.

Front 6

What are the other synonyms for bunde bone?

Back 6

It is commonly referred to as alveolar bone proper because of its intimate relationship with the PDL. It contains numerous small foramina that transmit the nerves and vessels of the PDL and is also called the cribiform plate. Radiographically, it appears as a dense opaque line called the lamina dura.

Front 7

What are the functions of alveolar bone?

Back 7

Anchoring function and it is able to deform slightly to accomodate the biting forces placed upon it

Front 8

What are PDL fiber bundles within the alveolar bone and cementum called?

Back 8

Sharpey's fibers

Front 9

What is the PDL derived from?

Back 9

dental follicle

Front 10

What establishes an anchor for the tooth in the alveolar bone?

Back 10

The fibroblasts of the PDL beging to synthesize collagen forming a fibrous bridge between the existing cemental and osseous collagen

Front 11

What is the function of the PDL?

Back 11

supports the tooth inside the socket and helps it withstand occlusal forces. also serves as a sensory organ

Front 12

Where is the PDL the thinnest?

Back 12

at the middle one-third of the root. it also becomes thinner as a person ages

Front 13

What cells are associated with the PDL?

Back 13

fibroblasts- most common cell of the PDL; cells continuously degrading and synthesizing collagen

epithelial cells- remnants of Hertwig's root sheath; no known function

undifferentiated mesenchymal cells- provide cellular pool for recruitment of new fibroblasts, cementoblasts, and osteoblasts

cementoblasts- found within PDL, but associated with surface of cementum

osteoblasts- within PDL, associated with surface of alveolar bone

osteoclasts- found in areas where the alveolar bone is undergoing resorption

Front 14

What types of collagen does the PDL consist of?

Back 14

Types I and type III collagen

Front 15

Alveolar crest group

Back 15

attached to tooth slightly apical to CEJ and insert into crest of alveolus

Front 16

horizontal group

Back 16

found apical to alveolar crest group; fibers oriented at right angle to the long axis of the tooth

Front 17

oblique group

Back 17

most common fiber group of PDL; osseous attachment is coronal to their origination on the cementum

Front 18

apical group

Back 18

run between the apical cementum directly to the apical alveolar bone

Front 19

interradicular group

Back 19

found in interradicular regions of multi-rooted teeth

Front 20

Are mature elastic fibers present in the PDL?

Back 20

No, but there are 2 types of immature elastic fibers present

Front 21

What are the 2 types of immature elastic fibers present in the PDL?

Back 21

Oxytalan fibers- run in vertical direction along surface of cementum to the root apices; play a role in regulating blood and lymphatic flow; most numerous in cervical region of PDL

elaunin fibers- span the PDL and form a sheath around the collagen bundles

Front 22

What is the function of the ground substance in the PDL?

Back 22

acts as a shock absorber against occlusal stresses; consists mostly of water and dermatan sulfate

Front 23

Where is the blood supply of the PDL dervied from?

Back 23

superior alveolar artery (maxilla) and inferior alveolar artery (mandible)

Front 24

What are perforating arteries?

Back 24

They are branches of the superior and inferior alveolar artery that run thru the alveolar bone and enter the PDL thru the cribiform plate. They are more numerous in posterior teeth and more common in the mandible than maxilla

Front 25

What is the direction are arterial and venous blood flow in the PDL?

Back 25

arterial blood moves from the apical to the crestal region while venous and lymphatic drainage occur in the opposite direction

Front 26

What is the nerve supply of the PDL?

Back 26

the PDL has a dual nerve supply: sympathetic nerve fibers of the autonomic system that regulate blood flow thru the PDL and afferent, mostly myelinated, sensory branches of the 2nd and 3rd divisions of the trigeminal nerve

Front 27

Where do nerve fibers enter the PDL?

Back 27

thru the apical ergion or thru the cribiform plate

Front 28

Which region contains the greatest number of nerve endings?

Back 28

the apical region, with one exception: in the upper incisors, nerve endings are also concentrated in the coronal half of the labial portion of he PDL

Front 29

What are the 4 types of nerve endings in the PDL?

Back 29

free nerve endings- most common; serve as nociceptors and mechanoreceptors; evenly distributed along length of PDL

Ruffini corpuscles- mechanoreceptors found near the root apex

coiled nerve endings- unknown function; found at mid-portion of PDL

Spindle-like endings- unknown function; least common; around root apex

Front 30

What does the term periodontium refer to?

Back 30

It refers to the alveolar bone-PDL-cementum complex

Front 31

What are the functions of the periodontium?

Back 31

attachment- the PDL keeps the tooth anchored in the jaw and helps to dampen occlusal forces

sensation- pain, touch, and pressure