Chapter 5 Midterm Questions Flashcards
What are the stages of tooth development?
bud, cap and bell stages
True or False
Each stage of tooth development is defined according to the shape of the ectoderm ally derived enamel organ, which is a part of the developing tooth.
True
What is the bud stage composed of?
rounded, localized growth of ectodermal cells surrounded by the proliferating mesenchymal cells, gains concave surface (begins cap stage)
The mesenchyme forms the __ ______
dental papilla (which becomes dental pulp)
What is the tissue surrounding the dental papilla and dental pulp?
dental follicle
What is the name of the cells that the enamel organ have differentiated into?
outer enamel epithelial cells
Ameloblasts form what substance on the tooth crown?
enamel
After the odontoblasts elongate, become columnar and polarize, they form an extracellular matrix, that is what percent of type I collagen fibers and non collagenous proteins?
90% type I collagen fibers
10% noncollagenous proteins (predentin)
When the cell moves pulp ward, what is the process called?
odontoblast process
The dentinal matrix becomes calcified in how many hours?
24
What is the name of the dentinal matrix before calcification and after calcification?
predentin before
dentin after
The initial formation of dentin (yellow) at the cuspal tips and the vascularized pulp organ are characteristics of what stage of tooth development?
dentinogenesis stage (follicular cells are differentiating around enamel organ and alveolar bone proper is beginning to define the dental crypt)
What are the two phases of dentinogenesis?
collagen matrix formation, deposition of calcium phosphate crystals in the matrix
At the bell stage, cells of the inner enamel epithelium elongate and are ready to become what?
active secretory ameloblasts
What are the five functional stages of ameloblasts?
morphogenesis organization and differentiation secretion maturation protection
The inner cell layer of the root sheath forms from what ?
inner enamel epithelium or ameloblasts in the crown (enamel is produced)
True or False
As the root sheath lengthens, it becomes the architect of the root. The length, curvature, thickness and number of roots are all dependent on the inner root sheath cells
True
What is intermediate cementum?
thin layer of acellular cementum that covers the ends of the dentinal tubule and seals the root surface and is composed of keratin-like protein
True or False
The outer root sheath cells disperse into small clusters and move away from the root surface as “epithelial” rests
True (root sheath bends at 45 degree angle , termed epithelial diaphragm)
What is the origin of ameloblast cells?
epithelial cells
What angle does the root sheath bend at?
45 degree angle
