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31 Cards in this Set

  • Front
  • Back
What is alveolar bone?
The osseous tissue of the maxilla and mandible that surrounds and supports teeth
What is alveolar bone derived from and when is it formed?
Derived from the dental follicle and it is formed during cementogenesis
What structure is composed of alveolar bone?
Alveolar process
What does the alveolar process consist of?
Outer cortical plate, central spongy bone, and bone lining the tooth socket
What is bundle bone?
The bone into which the collagen bundles of the PDL insert.
What are the other synonyms for bunde bone?
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.
What are the functions of alveolar bone?
Anchoring function and it is able to deform slightly to accomodate the biting forces placed upon it
What are PDL fiber bundles within the alveolar bone and cementum called?
Sharpey's fibers
What is the PDL derived from?
dental follicle
What establishes an anchor for the tooth in the alveolar bone?
The fibroblasts of the PDL beging to synthesize collagen forming a fibrous bridge between the existing cemental and osseous collagen
What is the function of the PDL?
supports the tooth inside the socket and helps it withstand occlusal forces. also serves as a sensory organ
Where is the PDL the thinnest?
at the middle one-third of the root. it also becomes thinner as a person ages
What cells are associated with the PDL?
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
What types of collagen does the PDL consist of?
Types I and type III collagen
Alveolar crest group
attached to tooth slightly apical to CEJ and insert into crest of alveolus
horizontal group
found apical to alveolar crest group; fibers oriented at right angle to the long axis of the tooth
oblique group
most common fiber group of PDL; osseous attachment is coronal to their origination on the cementum
apical group
run between the apical cementum directly to the apical alveolar bone
interradicular group
found in interradicular regions of multi-rooted teeth
Are mature elastic fibers present in the PDL?
No, but there are 2 types of immature elastic fibers present
What are the 2 types of immature elastic fibers present in the PDL?
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
What is the function of the ground substance in the PDL?
acts as a shock absorber against occlusal stresses; consists mostly of water and dermatan sulfate
Where is the blood supply of the PDL dervied from?
superior alveolar artery (maxilla) and inferior alveolar artery (mandible)
What are perforating arteries?
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
What is the direction are arterial and venous blood flow in the PDL?
arterial blood moves from the apical to the crestal region while venous and lymphatic drainage occur in the opposite direction
What is the nerve supply of the PDL?
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
Where do nerve fibers enter the PDL?
thru the apical ergion or thru the cribiform plate
Which region contains the greatest number of nerve endings?
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
What are the 4 types of nerve endings in the PDL?
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
What does the term periodontium refer to?
It refers to the alveolar bone-PDL-cementum complex
What are the functions of the periodontium?
attachment- the PDL keeps the tooth anchored in the jaw and helps to dampen occlusal forces

sensation- pain, touch, and pressure