Alveolar Bone

Question 1

What is the alveolar bone and what is its purpose

Answer 1

Specialised bone of the maxilla and mandible which supports and protects the tooth roots

Question 2

What is the alveolar bone composed of

Answer 2

• Alveolar bone proper

- Supporting bone

Question 3

What is the boundary of the alveolar bone

Answer 3

An arbitrary horizontal line at the bottom of the root apices, separating the alveolar bone from the body of the mandible and maxilla

Question 4

What calcified to form bone

Answer 4

Osteoid

Question 5

What is the main protein in the organic bone matrix

Answer 5

90% type 1 collagen

Question 6

What are the roles of collagen and non collagenous proteins in the alveolar bone

Answer 6

Collagenous = resilience to prevent fracture and ability to resist loads
Non-collagenous = play a role in mineralisation

Question 7

What cells secrete intrinsic and extrinsic collagen

Answer 7

Intrinsic = secreted by osteoblasts - i think this means collagen in the bones
Extrinsic = secreted by fibroblasts - i think this means collagen in the ECM

Question 8

What is the last thing that osteoblasts do in their lifecycle

Answer 8

Become embedded in the matrix which then mineralises, after it gets entrapped the osteoblasts becomes inactive osteocytes

Question 9

What are the bone lining cells

Answer 9

Flattened undifferentiated inactive osteoblasts cover the bone surface, they function as a barrier for certain ions

Question 10

Whats the difference in the nucleus’ of osteoblasts and osteoclasts

Answer 10

Osteoblasts = mononucleate
Osteoclasts = large multinucleate cells

Question 11

What do osteoclasts do

Answer 11

They create acidic environments and secrete enzymes which resorb bone, located in resorption howship’s lacunae

Question 12

What are osteoprogenitor cells

Answer 12

• Mesenchymal fibroblast-like cells
• Regarded as forming a stem cell population generating osteoblasts and osteoclasts
• Situated near blood vessels of the periodontal ligament space

Question 13

What does each lamella in compact lamellar bone have in it

Answer 13

A Haversian canal that contains blood vessels and nerves, surrounded by concentric lamellae, overall this forms and osteon

Question 14

Describe the thickness of the alveolar bone at different parts of the maxilla

Answer 14

The bone is thicker at the palatal aspects of the teeth composed to the buccal aspects

Question 15

Describe the thickness of the alveolar bone at different parts of the mandible

Answer 15

• In incisor and premolar regions (anteriorly), the cortical bone plate is thinner buccally compared to lingually
• In molar region (posteriorly) the cortical bone is thinner lingually and thicker buccally

Question 16

At which part of the teeth is the alveolar bone proper thinner and thicker

Answer 16

The alveolar bone proper is thin at the margins of the teeth (coronally) and thicker towards the root apex

Question 17

What is the inner alveolar bone proper, that surrounds the roots of the teeth, forming the tooth socket as referred to as

Answer 17

Inner cortical plate
Lamina Dura
Bundle bone
Cribiform Plate
Note: remember this part of the bone is compact bone

Question 18

What causes the sieve-like appearance of the inner alveolar bone proper

Answer 18

The numerous perforations formed by the vascular canals - Volkmann’s canals

Question 19

Between the external and internal cortical plates compact bone what is there

Answer 19

Variable amounts of spongy cancellous bone

Question 20

Is the external or internal layer of compact bone thicker

Answer 20

External is thicker

Question 21

What is the alveolar crest

Answer 21

Where the external and inner compact cortical plates meet

Question 22

What are the functions of the alveolar bone

Answer 22

• Support and protection
• Storage
• Blood cell formation
• Acts as a shock-absorber
• Attachment for teeth
• Strength
• Tooth movement

Question 23

How does the alveolar bone act as a storage ting

Answer 23

• Fat is stored in the bone marrow spaces

- Bone matrix acts as a reservoir for ions particularly calcium and phosphorus

Question 24

How does the alveolar bone act as an attachment ting

Answer 24

• Serves as an attachment apparatus for the teeth
• Supplies vessels to the periodontal ligament fibres
• Provides attachment to the periodontal ligament fibres
• Those that enter the bone are regarded as Sharpey’s fibres which act as an important buffer medium against stress

Question 25

How does the maintenance of the alveolar bone occur

Answer 25

• The teeth act as a functional matrix for the alveolar bone
• Therefore if there is failure of tooth development there alveolar bone is fail to fully form
• In addition when teeth are lost (following tooth extraction) the alveolar bone with atrophy