Chapter 6: Tooth Development and Eruption
11. What is the difference between succedaneous and nonsuccedanous teeth?
Succedaneous is permanent teeth with primary predecessors (include the anterior teeth and premolars), and nonsuccedanous is permanent teeth without primary predecessors (namely the molars).
12. What developmental disturbances can occur during the cap stage?
a. Dens in dente – enamel organ invaginates into the dental papilla
b. Germination – tooth germ tries to divide
c. Fusion – union of two adjacent tooth germs
d. Tubercle – extra cusp due to effects on enamel organ
13. What occurs during the bell stage, and what tissues are involved?
It’s the fourth stage of odontogenesis, in which differentiation occurs to its furthest extent, and the enamel organ assumes a bell shape. The enamel organ and dental papilla are involved during this stage.
14. What developmental disturbances can occur during the bell stage?
I’m still unsure about the answer(s) to this question. I’d emailed Mrs. Percell about it, and she told me to refer to table 6-3 (pg. 65-69) for list of developmental disturbances for each stage. Of course, I did that and saw that there were no developmental disturbances listed for the bell stage. Therefore, the only thing I can think of that would be a developmental disturbance for this stage is the enamel organ not assuming its bell-shaped form and differentiation of the cell types (listed in #15) will not be produce. Someone please double check this answer for me. Thanks.
15. What does the enamel organ consist of, and what is the function of each layer?
a. Outer enamel epithelium (OEE) – serve as protective barrier for the rest of the enamel organ during enamel production
b. Inner enamel epithelium (IEE) – will differentiate into enamel-secreting cells (ameloblasts) that form enamel matrix
c. Stratum Intermedium and stellate reticulum – help support the production of enamel matrix
16. Describe the layers of the dental papilla and the function of each layer.
a. Outer cells of the dental papilla (or peripheral cells) will differentiate into dentin-secreting cells (odontoblasts) that form dentin matrix
b. Inner cells of the dental papilla are the primordium of the pulp, or pulp tissue
17. Describe the dental sac and its function.
The outer dental sac increases in the amount of collagen fibers but undergoes differentiation into its dental tissues later than the enamel organ and dental papilla do.
18. Explain the stages of apposition and maturation during tooth development.
Apposition is the final stage of odontogenesis where the enamel, dentin, and cementum are secreted in successive layers, and maturation is reached when dental tissues are fully mineralized.
19. Describe the process of induction during tooth development.
The first stage of tooth development, known as the initiation stage, involves the physiological process of induction, which is an interaction between the embryological tissues. Studies show that the mesenchymal tissues must influence the ectodermal tissue to initiate odontogenesis, but mechanisms are unknown at this time.