lecture 1- anatomy of the periodontium Flashcards
what are the 4 structures of the periodontium?
Gingiva
periodontal ligament
root cementum
alveolar bone
what are the 2 regions of alveolar bone?
1) Alveolar bone proper (bundle bone)
2) alveolar process
what is the function of the periodontium?
- attach the tooth to bony tissues of the jaw
- maintain integrity of masticatory mucosa
cells of the periodontium originate from the ________ during development
neural crest (neural tube)
during development, stomadeal epithelium releases factors which initiate what?
epithelial-ectomesenchymal interactions
neural crest cells form ____________ beneath stomadeal epithelium
ectomesenchyme
what does the dental papilla give rise to?
dentin and pulp
what does the dental follicle form?
periodontium
which embryonic structure gives rise to the periodontium
dental follicle
the _________ determines the shape and form of a tooth
dental papilla
what forms her twig’s epithelial root sheath?
outer and inner enamel epithelium proliferating apically
what do the inner cells of the root sheath secrete?
enamel-related proteins (amelogenins)
_____________ cells of the dental follicle contact root surfaces following the fenestration of the root sheath
ectomesenchymal
________ induces differentiation of ectomesenchymal cells into cementoblasts
amelogenin
the Periodontal ligament is formed by ________ that are differentiated from the dental follicle lateral to the cementum
fibroblasts
_________ differentiate from dental follicle ectomesenchymal cells (alveolar bone proper)
osteoblasts
T/F: ectomesenchymal cells are lost after maturation is complete
False: ectomesenchymal cells remain in mature periodontium and participate in turnover
what are the 3 regions of gingiva?
1) free gingiva
2) attached gingiva
3) interdental papilla
what is free gingiva also called? where does it extend to
AKA “gingival sulcus, marginal gingiva, sulcus depth”
extends from the free gingival margin to the free gingival groove
the free gingival margin is the ______ end of the gingiva
coronal
the Free gingival margin is located 1.5-2 mm coronal to what structure?
the CEJ
the free gingival groove is the junction between which 2 structures?
junction between free and attached gingiva
which gingival structure correlates to the CEJ in young, healthy adults
free gingival groove
only correlates in 30-40% of adults
oral epithelium faces the ________
oral cavity
which oral epithelium faces the tooth surface without contacting it?
oral sulcular epithelium
____________ provides contact between gingiva and the tooth
junctional epithelium
perio probing will show where the ________ begins
junctional epithelium
what are the macroscopic limits of the free (marginal) gingiva?
extends from the:
free gingival margin
to the
free gingival groove
what is the MICROscopic limit of the free (marginal) gingiva?
extends from the free gingival margin to the junctional epithelium
why do we care about the limits of the free (marginal) gingiva?
these landmarks change from health to disease will determine the accuracy of your probe readings
attached gingiva is mainly attached to _________
alveolar bone
T/F: the width of attached gingiva is fairly constant
False
- increases with age
- widest in incisors, narrowest in premolars (maxillary)
- mandibular lingual: narrowest in incisors, widest in molars
what is stippling? what % of the population shows stippling?
small depressions on the attached gingiva
-found in 40% of adults
what is the mucogingival junction? (MGJ)
where is it NOT found?
-junction between attached gingiva and alveolar mucosa
NOT found in the palate (palate is keratinized)
attached gingiva and marginal gingiva are both ______ gingiva
keratinized
T/F: alveolar mucosa is keratinized
False: its non-keratinized
less than ___mm of attached gingiva will greatly increase the risk for gingival recession
2mm
what determines the shape of interdental papilla?
- the contact relationship between adjacent teeth
- width of approximate tooth surfaces
- course of CEJ
what is the “col”?
concavity seen in contact areas of premolar/molar region
non-keratinized epithelium
the bottom of the gingival sulcus in a healthy mouth is positioned apical to the CEJ: when is this condition most likely to occur?
at 40-60 years of age
oral epithelium is made of what type of epithelium?
keratinized, stratified, squamous epithelium
what are the layers of oral epithelium?
1) basal layer (stratum basale)
2) prickle cell layer (stratum spinosum)
3) granular cell layer (stratum granulosum)
4) keratinized cell layer (stratum corneum)
orthokeratinized epithelium lacks what structure?
a nucleus
what type of oral epithelial cells still have nuclear remnants?
parakeratinized
what changes as we move from the basal layer to the granular layer of oral epithelium?
- cytoplasmic tonofilaments and the # of desmosomes INCREASE
- the number of organelles DECREASES
keratinocytes make up what % of oral epithelium? clear cells?
keratinocytes- 90%
clear cells- 10%
what cell types make up the “clear cells” of the oral epithelium? what is the role of each of these cell types
- melanocytes (synthesize melanin pigment)
- langerhans cells (defense cells)
- Merkel’s cells (sensory)
characteristics of the basement membrane in oral epithelium:
- present between basal layer of oral epithelium and the connective tissue
- rich in glycoproteins
- 1-2 micrometers wide
- contains protein-polysaccharide complexes
what are the 2 layers of the basement membrane?
1) lamina lucida (LL)
2) lamina densa (LD)
which basement membrane layer sits adjacent to basal cells?
the lamina lucida
the lamina densa sits adjacent to the _________
connective tissues
**anchoring fibers project from the lamina densa into connective tissue
what are hemidesmosomes?
dense plaques that attach epithelium to the basement membrane
what is a pair of hemidesmosomes called?
a desmosome
Connective tissue projects into the epithelium, forming ________
connective tissue papillae
what is the name for the epithelial ridges that intervene between CT papillae?
rete pegs
when rete pegs fuse it as seen as ______
stippling
where are rete pegs missing?
at the junctional epithelium
what cell type is the most common defense cell of the oral epithelium?
Langerhans cells (a type of clear cells)
T/F: the “col” of the oral epithelium is keratinized
FALSE- its non-keratinized
since it is protected from abrasive forces in the mouth, it remains non-keratinized
what happens to the col after extraction?
it recedes into a flat, keratinized section of oral epithelium
