Perio: Alveolar Bone

Question 1

Discuss general characteristics of alveolar bone:

Answer 1

• Formed during fetal growth, consisting of calcified matrix with osteocytes
  (bone cells) which originate from osteoblasts
• Continual changes; however, retains same approximate form throughout life
• Balance between deposition by osteoblasts and resorption by osteoclasts
  (renewal and remodelling)

Question 2

Define the alveolar process and describe the layers that compose it

Answer 2

• Function: forms the bony sockets
  that provide support and protection
  for the roots of the teeth.
• Composed of:
• Alveolar bone proper (cribriform
  plate)- inner socket wall of thin,
  compact bone
• Supporting alveolar bone-
  consists of cancellous bone,
  facial (outer cortical) and lingual
  (inner cortical) plates of
  compact bone

Question 3

Define alveolus

Answer 3

The alveolar process is the lining of the tooth’s socket and referred to as the alveolus. Although the alveolar process is made up of compact bone, it may also be called the cribriform plate as it contains various holes where Volkmann canals pass from the alveolar bone and into the PDL.

Question 4

Explain the function of the alveolar bone in the periodontium

Answer 4

The main function of the alveolar bone is to house and support the teeth through the alveoli of each tooth. Supports teeth through periodontal fibers. Thanks to it, the teeth are held during actions, such as chewing, phonation and swallowing of food. And it also eliminates the forces generated by these actions.

Question 5

Describe the characteristics of cortical versus cancellous (spongy)
bone

Answer 5

Cancellous bone (aka as trabecular bone) can be visible on a radiograph.
Increased forces = increased trabeculae

The supporting alveolar bone structure is comprised of both cortical and trabecular bone.
The cortical bone, or cortical plates, contain plates of compact bone which are located on the facial and lingual surfaces of the alveolar bone. These cortical plates are typically about 1.5 to 3 mm thick over the posterior teeth. The thickness can vary drastically around the anterior teeth. The trabecular bone contains cancellous bone that is located between the alveolar bone proper and the plates of cortical bone. The alveolar bone which is present between the two neighboring teeth is the interdental septum or the interdental septum or bone.

Question 6

Define alveolar crest and explain its appearance on radiographs

Answer 6

Radiographs are useful
to identify:
* Crest of alveolar bone
* Height
* Slope
* Interdental bone septum
– may indicate
periodontal disease

Question 7

Describe the periosteum and its function

Answer 7

Alveolar Bone
* Covered by periosteum- a dense layer of tissue that lines the outside of the
bone and plays an active role in bone formation
* Fibrous outer layer is responsible for attachment of tissue to bone
* Cambium layer contains progenitor cells that develop into osteoblasts
* Becomes unstable if periodontal disease is present

The gingiva is attached to the periosteum of the alveolar process.
The attached gingiva is tightly bound to the cementum on the cervical
third of the tooth root, and to the periosteum of the alveolar bone.

Question 8

List factors that can affect the alveolar bone

Answer 8

The alignment of the teeth, the angulation of the roots in the bone,
and occlusal forces affect the height and thickness of the bony
plates (facial and lingual)
* Also affected by:
* Function
* Age
* Disease related change
* Hormones
* Host factors
* Systemic disease

Question 9

Cross-section of the mandible
reveals three bony layers of
the alveolar process:

Answer 9

Question 10

describe the following:

Answer 10

Question 11

Describe relationship between gingiva, Alveolar process and Periosteum:

Answer 11