Alveolar bone and related pathologies Flashcards
What forms the cribriform plate?
result of attachment of PDL fibers and passage of vessels and nerves into and out of the PDL
What does bundle bone mean?
refers to the bone in which Sharpey’s fibers are embedded
What is the Alveolar bone proper also called?
cribriform plate or bundle bone
What is woven bone?
immature bone in which the collagen fiber matrix is randomly oriented
when is woven bone formed?
newly formed bone or associated with healing wounds
What are the characteristics of woven bone?
-more cells per unit area than mature bone
-greater volume of non-collagenous protein
-forms more rapidly than mature bone
What is spongiosa? (cancellous)
trabecular bone that lies between the cortical plates and within the marrow spaces
What is the supporting alveolar bone made of?
facial and lingual cortical plates
-lamellar bone
-haversian bone
-interstital bone
What type of bone is this?
lamellar bone
what type of bone is this?
haversian
What is the make up of bone?
67% inorganic material
33% organic material
What is the inorganic material of bone?
Ca hydroxyapatite
What is the organic material of bone?
28% collagen
5%- osteocalcin, sialoprotein, phosphoprotein, osteonectin, BMP
What are all of the cells associated with bone?
-osteoblasts
-osteocytes
-osteoclasts
-bone lining cells
-chondroblasts
-chondrocytes
-mesenchymal cells
What is an osteocyte?
osteoblast that has been entrapped by it’s own osteoid matrix
What are canaliculi?
proccesses through bone that radiate in all directions and allow for diffusion of substances throuhg the bone
What is the function of canaliculi?
-connection to other osteocytes/osteoblasts
-allowing cell-to-cell communication
-may have some mechanoreception properties as well
What is the periosteum?
dense connective tissue bound to bone by sharpeys fibers that contain blood vessels, nerves, and three cell layers
What are the three cell layers of the periosteum?
-peripheral cell layer of fibroblasts
-intermediate cell layer of undifferentiated mesenchymal cells
-proximal cell layer of osteoblasts
What is the endosteum?
lines the medullary cavity and cancellous bone
-generally has the same composition as periosteum but is significantly thinner
What is this pointing to?
endosteum
What is this?
periosteum
Where is type 1 collagen in bone ?
ubiquitous in distribution
Where is type 2 collagen in bone?
primarily a cartilage protein
Where is type 3 cartilage in bone?
granulation and mesenchymal tissues
where is type 5 cartilage in bone?
stromal connective tissue and promotes cellular attachment and migration
Where is type 10 collagen in bone?
in the growth plate, facilitates the conversion of cartilage to bone
What are some non-collagenous proteins associated with bone matrix?
-osteonectin
-osteopontin
-osteocalcin
-sialoprotein
-phosphoprotein
-glycoprotein
-bone specific protein
-BMP
-carboxyglutamic acid containing protein
What are characteristics of non-collagenous proteins in the bone?
-highly acidic nature
-high aggregation tendencies
-calcium binding properties
What is in-situ remodeling?
a process of osteoclast resorption, and bone replacement by osteoblast activity
-mostly seen in areas of alveolar bone affected by orthodontics
What is intramembranous bone formation?
bone formation within or between connective tissue membranes consisting of type I collagen
-bone does NOT replace cartilage as it done in endochondral bone
What is endochondral bone formation?
bone formation within hyaline cartilage that involves a concomitant replacement of the cartilage framework by bone
Steps in in-situ remodeling?
-osteoclast; resorption
-osteoblast precursor; reversal
-mature osteoblast; formation
-new bone; resting (osteocytes)
Where is intramembranous bone formed?
in the inner spongy layers of bones as well as sutures
IS intramembranous bone formation quick?
yes, it is done rapidly and disorganized
What is an example of bone type that is formed by intramembranous ossification?
woven bone
What do osteoblasts do in intramembranous ossification?
osteoblasts secrete matrix vesicles that mineralize surrounding collagen fibers. the osteoblasts usually become trapped themselves and become osteocytes
What are the contents of the matrix vesicle of bone
-alkaline phosphatase
-pyrophosphatase
-glycoproteins
-phosphoproteins
-phospholipids
Where is endochondral ossification seen?
vertebrae, long bones, base of skull, and head of mandible
What are the steps of endochondral ossification?
-mesenchymal cells make general outline of final bone shape
-cells differentiate into cartilage cells (chondroblasts) which increase in size, secrete collagen and mineralize it with matrix vesicles
-chondrocytes die
-vascular tissue form periochondrium invade the cartilage allowing chondroclasts and mesenchymal cells to enter the area
-chondroclasts eat away the cartilage
-newly differentiated osteoblasts deposit osteoid into cartilage
-osteoid is mineralized by osteocytes and bone is made
What is the growth of endochondral bone dependant on?
growth of cartilage and stops once the cartilage has been completely removed
What are the zones of cellular activity of endochondral ossification?
-reserve or resting chondrocytes
-proliferation
-maturation
-hypertrophy and calcification
-cartilage degeneration
-osteogenesis
What helps to control bone metabolism?
systemically- hormones
locally- mechanical factors, growth factors, and cytokines
What hormones are important to bone metabolism?
-parathyroid hormone
-1,25-dihydroxyvitamin D
-calcitonin
-estrogen
-glucocorticoids
what cytokines and growth factors are important to bone metabolism?
-interleukin 1
-interleukin 6
-BMP2 and BMP7
-transforming growth factor
-insulin growth factor 1 and 2
-platelet derived growth factor
-fibroblasts growth factor-beta
What do osteoblasts secrete to activate osteoclasts?
IL-6
What cytokines cause osteoblasts to secrete IL-6?
-interleukin 11
-tumor necrosis factor alpha
-prostaglandins E2
-parathyroid hormone
-1,25-dihydroxyvitamin D
How do osteoclasts cause the breakdown of bone ?
creation of localized acidic pH to demineralize hydroxyapatite and a variety of enzymes to degrade the organic bone matrix
What enzymes are created to degrade organic bone matrix?
lactic acid
citric acid
free protons
acid phosphatase
aryl sulfatase
collagnease
gelatinase
What determines the facial and lingual shape of cortical bone?
-facial-lingual alignment of teeth
-mesial to distal contour of CEJ
-facial-lingual width of teeth
-presence of enamel pearls or cervical enamel projections
What determines the shape of interproximal alveolar bone?
-facial to lingual contour of CEJ
-mesial or distal tilt of the tooth
-root proximity
-presence of enamel pearl
-state of tooth eruption
What are fenestrations of alveolar bone?
isolated “port-hole” in the cortical bone that allows exposure of the underlying root surface
What is a dehiscence of alveolar bone?
denuded area of cortical bone that extends through through the marginal bone creating a ‘cleft-like’ defect
What is exostosis?
area of bone formation that exceeds the average for a given anatomical area
-term used in reference to maxillary facial and lingual and mandibular facial
What are torus/tori?
area of bone formation that exceeds the average for a given anatomical area
-term used in reference to mandibular lingual or midline of palate
What is a giant cell tumor?
generally asymptomatic causing a painless expansion of bone
-usually a single lesion that can either unilocular or multilocular
-often confused with ameloblastoma or periapical granumlona or periapical cyst
What is the histology of a giant cell tumor?
presence of numerous multinucleated giant cells in a stroma of ovoid and spindle shaped mesenchymal cells
what this?
giant cell tumor
What is multiple myeloma?
malignancy of plasma cell origin that accounts for nearly 50% of all malignancies involving bone
What cell types do multiple myeloma come from?
abnormal monoclonal cells
What do patients with multiple myeloma typically also suffer from?
kidney failure due to overload of circulating light chain proteins produced by abnormal plasma cells
What does histology of multiple myeloma show?
monotonous sheets of neoplastic, variably differentiated, plasmacytoid cells that invade and replace host tssue
what does multiple myeloma look like radiographically?
look like punched out areas in the cranium
-filled with neoplastic plasmacytoid cells
what this?
multiple myeloma
what this?
multiple myeloma
What is osteogenic sarcoma?
malignancy of mesenchymal cells that have the ability to produce osteoid or immature cells
What is the most common type of malignancy that originates in the bone?
besides hematopoietic neoplasms, osteogenic sarcoma
What are the most common symptoms of osteogenic sarcoma?
pain and swelling
What are radiographic findings of osteogenic sarcoma?
anywhere from dense sclerosis to a mixed sclerotic-radiolucent lesion
-25% show sunburst pattern
what this?
osteogenic sarcoma
What is the embryonic origin of enamel?
ectoderm
What is the embryonic origin of dentin?
mesenchyme and ectomesenchyme
What is the embryonic origin of cementum?
mesenchyme and ectomesenchyme
What is the embryonic origin of bone?
mesenchyme and ectomesenchymeW
What is the matrix forming cell of enamel?
ameloblast
What is the matrix forming cell of dentin?
odontoblast
What is the matrix forming cell of cementum?
cementoblast
What is the matrix forming cell of bone?
osteoblast
What is the mechanism of growth of enamel?
appositional
What is the mechanism of growth of dentin?
appositional
What is the mechanism of growth of cementum?
appositional
What is the mechanism of growth of bone?
appositional and interstitial
What is the percent mineral of enamel?
96%
What is the percent mineral of dentin?
65-70%
What is the percent mineral of cementum?
45-50%
What is the percent mineral of bone?
60-67%
What is the organic matrix of enamel?
amelogenin and enamelin
What is the organic matrix of dentin?
collagen type I
What is the organic matrix of cementim?
collagen type I
What is the organic matrix of bone?
collagen type I
Is there blood supply of enamel?
no
Is there blood supply of dentin?
no
Is there blood supply of cementum?
no
Is there blood supply of bone?
yes
Is there innervation of enamel?
no
Is there innervation of dentin?
limited
Is there innervation of cementum?
no
Is there innervation of bone
yes
What is the intercellular space of enamel?
none
What is the intercellular space of dentin?
dentinal tubules
What is the intercellular space of cementum?
lacunae and canaliculi
What is the intercellular space of bone?
lacunae and canaliculi
