Tooth Formation/Development Flashcards
T/F: The dental lamina comes from mesenchyme.
False
Ectoderm
What determines the type of tooth to be formed?
Ectomesenchyme underlying the dental lamina
What three things form the tooth germ?
Enamel organ, dental papilla, dental follicle
What is the role of the enamel organ?
Forms enamel, initiates dentin formation
T/F: Ameloblasts differentiate before odontoblasts.
True
T/F: Enamel is formed before the formation of dentin begins.
False
How much root is formed when the tooth begins to erupt?
50%
What is the primary function of the dental pulp?
Form dentin
T/F: Dentin is harder than cementum.
True
What characterizes parakeratinized tissue?
Nuclei in the stratum corneum
T/F: Masticatory mucosa has a thin submucosa.
True
Not very movable
T/F: The neonatal line is only found in enamel.
False
Both dentin (lines of Owen) and enamel (stria of Rhetzias)
T/F: Stria of rhetzias and perikymata are normal structures.
True
Enamel _______ are ribbon like and extend roughly 1/3rd into enamel.
tufts
Enamel _______ are formed from the odontoblastic processes.
spindles
_________ is at the cusp tips and incisal edges.
Gnarled enamel
At the time of secretion, what is the level of mineralization of dentin and enamel?
Dentin = none
Enamel = 30% mineralized
Where does enamel secretion start?
Cusp tips/incisal edges
What cells form the reduced enamel epithelium?
Ameloblasts after enamel secretion
What characterized enamel hypoplasia?
Not enough enamel matrix
T/F: The DEJ is a strong, scalloped border.
True
What is the major component of dentin matrix?
Type I Collagen
Which type of dentiogenesis imperfecta is associated with osteogenesis imperfecta?
Type 1
What are lines of von Ebner?
Normal lines with the alignment of collagenous fiber of dentin
Which lines in the dentin lead to the neonatal line?
Lines of Owen
T/F: Secondary dentin is laid down very quickly in response to carries.
False
Secondary is slowly deposited throughout life (why the pulp gets smaller)
T/F: Secondary dentin has the same structure as primary dentin.
True
T/F: Tertiary dentin requires a stimuli.
True
Carries, trauma
What is the difference between repairative and reactive dentin?
Both tertiary
Repairative: laid down by newly differentiated mesenchymal cell
Reactive: laid down by already differentiated odontoblast
T/F: Sclerotic dentin describes empty dentin tubules.
False
Dead tracks = empty tubules
Sclerotic dentin = excessive dentin laid down over time
T/F: The epithelial root sheath forms the roots of the tooth.
True
What is the approximated density of tubules?
20,000-30,000 per millimeter
T/F: Peritubular dentin is hyper-mineralized dentin directly surrounding tubules.
True
________ is hypomineralized and makes up the bulk of the dentin.
Intertubular dentin
T/F: Dentin and pulp are both from the neural crest cells.
True
Describe the layers at the pulp-dentin junction.
Odontoblastic zone, cell free zone of Weil, cell rich zone (mesenchymal cells), deep pulp
What is found in the deep pulp?
Plexus of rashkow
T/F: There is sympathetic nervous supply to capillaries in the pulp and tubules from the Trigeminal nerve.
True
T/F: The number of cells in the pulp increases over time.
False
More type 1 and 3 collagen; less cells
What is the difference between a true pulp stone and false pulp stone?
True: has tubular dentin
False: irregular calcified tissue
What is primary cementum?
Completely acellular and connects to dentin
What is secondary cementum?
Acellular and cellular (lower 3rd of tooth); connects to PDL
What is the major cell type of the PDL?
Fibroblasts
Which part of the alveolar bone is attached to the PDL?
Bundle bone
What is the function of the cribriform plate?
Allows nutrients to get to the PDL
T/F: Epithelium in the sulcus is keratinized.
False
T/F: The junctional epithelium has only a single layer of squamous epithelium.
True
Where is sulcular fluid produced?
Connective tissue in gingiva
What structure splits the tongue into anterior 2/3rds and posterior 1/3?
Sulcus terminalis
Which papilla of the tongue are most numerous and have no taste buds?
Filiform
Which tongue papillae have taste buds and small salivary glands (of von Ebner)?
Circumvallate papillae
Found along sulcus terminalis
Which papillae are found on the lateral parts of the tongue?
Foliate - have taste buds
Which cells in taste buds are the chemoreceptors and have a nucleus found in the middle of the bud?
Gustatory cells
What will be distinct about cells in serous acini?
Lots of organelles
Which type of acini have zymogen granules?
Serous acini
Serous deminlumes will be seen in which type of acini?
Mixed (submandibular)
Striated ducts are found in which glands?
Serous gland - saliva is modified as it exits the duct
T/F: Saliva in a mucous gland is modified as it goes through the duct.
False
What is done by the intercalated ducts?
Secrete bicarbonate (HCO3-), reabsorb Cl-
What types of glands are the salivary glands?
Parotid - serous
Sublingual - mixed (mucous)
Submandibular - mixed (mostly serous)
Von Ebners - serous
What is done by the striated ducts?
Secrete K+, reabsorb Na+
The major salivary glands contain which type of secretory unit?
Tubuloacinar
