Alveolar Bone Flashcards
What is the alveolar bone and what is its purpose
Specialised bone of the maxilla and mandible which supports and protects the tooth roots
What is the alveolar bone composed of
- Alveolar bone proper
- Supporting bone
What is the boundary of the alveolar bone
An arbitrary horizontal line at the bottom of the root apices, separating the alveolar bone from the body of the mandible and maxilla
What calcified to form bone
Osteoid
What is the main protein in the organic bone matrix
90% type 1 collagen
What are the roles of collagen and non collagenous proteins in the alveolar bone
Collagenous = resilience to prevent fracture and ability to resist loads Non-collagenous = play a role in mineralisation
What cells secrete intrinsic and extrinsic collagen
Intrinsic = secreted by osteoblasts - i think this means collagen in the bones Extrinsic = secreted by fibroblasts - i think this means collagen in the ECM
What is the last thing that osteoblasts do in their lifecycle
Become embedded in the matrix which then mineralises, after it gets entrapped the osteoblasts becomes inactive osteocytes
What are the bone lining cells
Flattened undifferentiated inactive osteoblasts cover the bone surface, they function as a barrier for certain ions
Whats the difference in the nucleus’ of osteoblasts and osteoclasts
Osteoblasts = mononucleate Osteoclasts = large multinucleate cells
What do osteoclasts do
They create acidic environments and secrete enzymes which resorb bone, located in resorption howship’s lacunae
What are osteoprogenitor cells
- Mesenchymal fibroblast-like cells
- Regarded as forming a stem cell population generating osteoblasts and osteoclasts
- Situated near blood vessels of the periodontal ligament space
What does each lamella in compact lamellar bone have in it
A Haversian canal that contains blood vessels and nerves, surrounded by concentric lamellae, overall this forms and osteon
Describe the thickness of the alveolar bone at different parts of the maxilla
The bone is thicker at the palatal aspects of the teeth composed to the buccal aspects
Describe the thickness of the alveolar bone at different parts of the mandible
- 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
At which part of the teeth is the alveolar bone proper thinner and thicker
The alveolar bone proper is thin at the margins of the teeth (coronally) and thicker towards the root apex
What is the inner alveolar bone proper, that surrounds the roots of the teeth, forming the tooth socket as referred to as
Inner cortical plate Lamina Dura Bundle bone Cribiform Plate Note: remember this part of the bone is compact bone
What causes the sieve-like appearance of the inner alveolar bone proper
The numerous perforations formed by the vascular canals - Volkmann’s canals
Between the external and internal cortical plates compact bone what is there
Variable amounts of spongy cancellous bone
Is the external or internal layer of compact bone thicker
External is thicker
What is the alveolar crest
Where the external and inner compact cortical plates meet
What are the functions of the alveolar bone
- Support and protection
- Storage
- Blood cell formation
- Acts as a shock-absorber
- Attachment for teeth
- Strength
- Tooth movement
How does the alveolar bone act as a storage ting
- Fat is stored in the bone marrow spaces
- Bone matrix acts as a reservoir for ions particularly calcium and phosphorus
How does the alveolar bone act as an attachment ting
- 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
How does the maintenance of the alveolar bone occur
- 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
