Alveolar bone and pathologies

Question 1

cribriform plate

Answer 1

The cribriform plate is formed as a result of attachment of the PDL fibers and passage of vessels and nerves into and out of the PDL.
bone lining the alveolar socket

Question 2

bundle bone

Answer 2

The term bundle bone refers to that bone in

which Sharpey’s fibers (PDL) are embedded.

Question 3

Woven Bone
cells?
non-collagenous proteins?
rate of formation?

Answer 3

Woven Bone
• Immature bone in which the collagen fiber matrix is randomly oriented. This type of bone is generally newly formed (embryologic development) or associated with healing wounds.
§ More cells per unit area than mature bone
§ Greater volume of non-collagenous protein
§ Forms more rapidly than mature bone

Question 4

Spongiosa (a.k.a. Cancellous)

Answer 4

• Trabecular bone that lies between the cortical plates and

within the marrow spaces

Question 5

lining cells of trabeculae

Answer 5

osteoblasts

Question 6

Structural Organization of the Alveolar Process

Answer 6

Supporting Alveolar Bone
• Facial and lingual cortical plates

Made of:
§ Lamellar bone
§ Haversian bone
§ Interstitial bone

spongy bone between the plates

Question 7

Structural Organization of the Alveolar Process, composition of bone

Answer 7

see attatched

Question 8

Cells Associated With Bone/cartilage

Answer 8

Ø   Osteoblasts 
Ø   Osteocytes 
Ø   Osteoclasts 
Ø   Bone Lining Cells 
Ø   Chondroblasts 
Ø   Chondrocytes 
Ø   Mesenchymal Cells

Question 9

Osteocyte

Answer 9

Osteocyte is an osteoblast that has been entrapped by it’s own osteoid matrix

Question 10

Canaliculi

Answer 10

radiate in all directions, and allow diffusion of substances
throughout bone. Processes of the osteocytes travel within the canaliculi,
and connect to other osteocytes/osteoblasts, allowing cell-to-cell
communication. May have some mechanoreception properties, as well

Question 11

Periosteum

contents? layers?

Answer 11

A dense connective tissue, bound to bone by Sharpey’s fibers, that contains blood vessels, nerves,

three cell layers: 
§  Peripheral cell layer of fibroblasts 
§  Intermediate cell layer of undifferentiated  
     mesenchymal cells 
§  Proximal cell layer of osteoblasts

Question 12

Endosteum

Answer 12

Lines the meduallary cavity and cancellous bone (trabeculae).
Generally has the same composition as periosteum but is
significantly thinner

Question 13

collagens associated with bone

Answer 13

types 1,2,3,5,10

Question 14

type 1 collagen in bone

Answer 14

Fibrillar: ubiquitous in distribution

Question 15

type 2 collagen in bone

Answer 15

Fibrillar: primarily a cartilage protein

Question 16

type 3 collagen in bone

Answer 16

Fibrillar: granulation and mesenchymal tissues

Question 17

type 5 collagen in bone

Answer 17

fibrillar: stromal connective tissue and promotes cellular

attachment and migration

Question 18

type 10 cartilage in bone

Answer 18

Growth Plate: facilitates conversion of cartilage to bone

Question 19

Non-collagenous proteins associated

with bone matrix include:

Answer 19

Ø  Osteonectin 
Ø  Osteopontin 
Ø  Osteocalcin 
Ø  Sialoprotein 
Ø  Phosphoprotein 
Ø  Glycoprotein 
Ø  Proteoglycan 
Ø  Bone Specific Protein 
Ø  Bone morphogenetic protein (BMP) 
Ø  Carboxyglutamic acid containing protein

Question 20

The non-collagenous matrix proteins of bone

are characterized by their:

Answer 20

Ø highly acidic nature
Ø high aggregation tendencies
Ø calcium binding properties

Question 21

In-Situ Remodelling, commonly seen where in dentistry?

Answer 21

A process of osteoclast resorption, and bone replacement by osteoblast activity.
Mostly seen in areas of alveolar bone affected by orthodontics.

Question 22

Intramembranous Bone Formation

Answer 22

Bone formation within or between connective tissue
membranes consisting of Type I collagen. Bone does
not replace cartilage as does endochondral bone.

This type of bone formation is found in the inner spongy layers of bone, as well as sutures. It is an extremely rapid and disorganized method of bone deposition, and allows for growth of the tissues surrounding it. Woven bone is an example of intramembranous bone growth.

Osteoblasts secrete matrix vesicles that mineralize surrounding collagen fibres. The osteoblasts usually become trapped themselves,
becoming osteocytes.

Question 23

contents of osteoblasts secretory vesicles

Answer 23

Ø   Pyrophosphatase 
Ø   Alkaline phosphatase 
Ø   Glycoproteins 
Ø   Phosphoproteins 
Ø   Phospholipids

Question 24

Endochondral Bone Formation

Answer 24

Bone formation within hyaline cartilage that involves a
concomitant replacement of the cartilage framework by
bone

Mostly seen in the vertebrae, long bones, base of the skull, and
head of the mandible.

Mesenchymal cells make the general outline of the final bone
shape. The cells differentiate into cartilage cells
(chondroblasts), which increase in size, secrete collagen and
mineralize it with matrix vesicles. The newly formed
chondrocytes eventually die. Vascular tissue from the
surrounding perichondrium invades the cartilage, allowing
chondrocytes and mesenchymal cells to enter the area. The
chondrocytes eat away the cartilage, and newly differentiated
osteoblasts deposit osteoid onto the cartilage. The osteoid is
mineralized by osteocytes, and bone is made.

The growth of these bones is dependant on the growth of the
cartilage, and stops once the cartilage is been completely
removed

Question 25

zones of activity in endochondral ossification

Answer 25

``` Ø Reserve or resting chondrocytes Ø Proliferation Ø Maturation Ø Hypertrophy and calcification Ø Cartilage degeneration Ø Osteogenesis ```

Question 26

label this endochondral slide

Answer 26

Question 27

control of bone metabolism, levels? | hormones?

Answer 27

Bone metabolism is controlled systemically by hormones and locally by mechanical factors, growth factors, and cytokines. ``` Hormones important to bone metabolism include: Ø Parathyroid hormone (PTH) Ø 1,25-dihydroxyvitamin D Ø Calcitonin Ø Estrogen Ø Glucocorticoids ```

Question 28

Cytokines and growth factors important to bone metabolism include, important one?

Answer 28

Ø Interlukin-1 (IL-1) Ø Interlukin-6 (IL-6): made by blasts to stimulate clast differentiation=resorbtion occurs Ø BMP-2 and BMP-7 Ø Transforming Growth Factor (TGF-) Ø Insulin-like growth factor (IGF-I and IGF-II) Ø Platelet-derived growth factor (PDGF) Ø Fibroblast growth factor-beta (FGF-)

Question 29

what stimulates IL-6 production?

Answer 29

Under conditions that favor bone resorption, osteoblasts can be stimulated by cytokines and hormones to produce IL-6 which, in turn, promotes differentiation of osteoclasts. Examples of such stimulating cytokines include: Ø Interleukin-11 (IL-11) Ø Tumor necrosis factor-alpha (TNF-) Ø Prostaglandins E2 (PGE2) Ø Parathyroid hormone (PTH) Ø 1,25-dihydroxyvitamin D

Question 30

how osteoclasts resorb bone, rxn, enzymes?

Answer 30

``` Osteoclastic resorption of bone involves the creation of a localized acidic pH to demineralize hydroxyapatite, and a variety of enzymes that degrade the organic bone matrix: carbonic anhydrase Ø Lactic acid Ø Citric acid Ø Free protons (H+) Ø Acid phosphatase Ø Aryl sulfatase Ø Collagenase (MMP) Ø Gelatinase (MMP) ```

Question 31

Architecture (shape) of the tooth-associated | facial and lingual cortical bone is dictated by:

Answer 31

Ø Facial-lingual alignment of teeth Ø Mesial to distal contour of the CEJ Ø Facial-lingual width of teeth Ø Presence of enamel pearls or cervical enamel projections

Question 32

Architecture (shape) of the interproximal | alveolar bone is dictated by:

Answer 32

``` Ø Facial to lingual contour of the CEJ Ø Mesial or distal tilt of the tooth Ø Root proximity Ø Presence of enamel pearls Ø State of tooth eruption ```

Question 33

Fenestration

Answer 33

An isolated “port-hole” in the cortical bone that allows exposure of the underlying root surface only part of root exposed

Question 34

Dehiscence

Answer 34

A denuded area of cortical bone that extends through the marginal bone creating a “cleft-like” defect can see the whole root

Question 35

Exostosis

Answer 35

An area of bone formation that exceeds the average for a given anatomical area. The term is generally used in reference to the maxillary facial and lingual and mandibular facial

Question 36

Torus /Tori

Answer 36

An area of bone formation that exceeds the average for a given anatomical area. The term is used in reference to the mandibular lingual or midline of the palate

Question 37

``` Giant Cell Tumor symptoms? locular? confused with? histologically characterized by? ```

Answer 37

Ø Generally asymptomatic causing a painless expansion of bone Ø Usually a single lesion that can be either unilocular or multilocular Ø Often confused with ameloblastoma or periapical granuloma or periapical cyst Ø Histology characterized by presence of numerous multinucleated giant cells in a stroma of ovoid & spindle shaped mesenchymal cells

Question 38

Multiple Myeloma accounts for what % of malignancies involving what tissue? origin of the cells? frequent complication?

Answer 38

Ø Malignancy of plasma cell origin that accounts for nearly 50% of all malignancies involving bone Ø The abnormal plasma cells are typically monoclonal (arise from a single cell) Ø Patients frequently suffer kidney failure due to overload of circulating light chain protein (Bence Jones Protein) produced by the abnormal plasma cells

Question 39

Multiple Myeloma histology and radiology

Answer 39

Ø Histology shows monotonous sheets of neoplastic, variably differentiated, plasmacytoid cells that invade and replace normal host tissue Ø Radiographically, patients may exhibit “punched out” areas in the cranium. Such areas are filled with the neoplastic plasmacytoid cells

Question 40

Osteogenic Sarcoma incidence? common symptoms? radiographs?

Answer 40

Ø A malignancy of mesenchymal cells that have the ability to produce osteoid or immature bone Ø Excluding hematopoietic neoplasms, osteogenic sarcoma is the most common type of malignancy to originate within bone Ø Pain and swelling are the most common symptoms Ø Radiographic findings vary from dense sclerosis to a mixed sclerotic-radiolucent lesion. About 25% of lesions exhibit a “sunburst” patter

Question 41

Comparison of the Four Mineralized Tissues chart | origin, matrix-forming cell, mech of growth, % mineral, organic matrix, blood?, inn? intracellular space?

Answer 41