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dental organ is derived from what type of tissue
dental papilla turns into what?
dentin and pulp
what is the function of the dental papilla?
determines the shape and form of the tooth
periodontium is formed by what?
PDL is formed by what type of cells?
describe the differentiation of osteoblasts
they differentiate from the dental follicle ectomesenchyme
what type of germ cell remains in mature periodontium?
define free gingival groove
- - junction between free/attached gingiva
- - corresponds to CEJ
- - only 30-40% of adults
describe the morphology of attached gingiva in relation to age
width increases with age
what percentage of adults have stippling?
what type of epithelium is Col
what the the two types of keratinized layers in oral epithelium?
- 1. orthokeratinized (no nucleus)
- 2. parakeratinized (nuclear remnants)
what is the predominant cell type in oral epithlium?
from the basal layer to the granular layer what patterns are present?
- 1. increase in tonofilaments and desmosomes
- 2. decrease in organelles
what are the 2 layers of the basement membrane?
- 1. lamina lucida: adjacent to basal cells
- 2. lamina densa: adjacent to CT
what attaches epithelium to BM?
what is the cause of stippling?
fusion of rete pegs
describe the thickness of JE
widest in coronal portion (15-20 cells thick) and thin at CEJ (3-4 cells)
how does the cellular turnover rate of JE compare to oral epithelium?
faster than OE
what are 4 differences between OE and JE?
- 1. size of cells, JE > OE
- 2. Intracellular space, JE > OE
- 3. Number of desmosomes, JE< DE
- 4. JE physically attached to tooth
list 4 fiber types in the lamina propria
- 1. collagen
- 2. reticulin
- 3. oxytalan
- 4. elastin
describe collagen in terms of lamina propria
- 1. cross banding
- 2. produced by fibroblasts, cementoblasts, osteoblasts
- 3. most abundant
describe reticulin in terms of lamina propria
- 1. adjacent to BM
- 2. around blood vessels
describe oxytalan in terms of lamina propria
- 1. mostly in PDL
- 2. runs parallel to long axis of tooth
describe elastin in terms of lamina propria
it is around blood vessels
list/define 4 types of gingival fibers
- 1. circular: encircle tooth
- 2. dentogingival: cementum to free gingival
- 3. dentoperiosteal: cementum to attached gingiva
- 4. transseptal: tooth to tooth
how are characteristics of tissue differentiation determined?
genetically rather than environmentally
what is the function of the PDL
distribution of force and tooth mobility
what are 4 types of fibers in the PDL?
- 1. alveolar crest
- 2. horizontal
- 3. oblique
- 4. apical
list 4 ways in which cementum is different than bone
- 1. no blood vessels
- 2. no lymphatics
- 3. no innervations
- 4. no physiologic resorption/remodeling
what percentage of cementum is composed of HA?
list 5 types of cementum fibers
- 1. intrinsic: produced by cementoblasts and parallel to root
- 2. Extrinsic: sharpey's fibers produced by PDL fibroblasts
- 3. acellular extrinsic fiber cementum: coronal to middle of root
- 4. cellular mixed stratified cementum: apical third
- 5. cellular intrinsic fiber cementum
what is the thickness of cementum?
- cervical: 20-50um
- apical: 150-250um
what is the origin of alveolar bone?
dental follicle but forms independent of tooth development.