2b Odontogenesis Flashcards
What stage is tooth shape determined?
between bud and cap stage
What transciption factors determine posterior teeth?
Dix1/2 and Barx-1
What transcription factors determine anterior teeth
Msx-1/2 and Alx-3
What happens to the reduced ameloblasts and other remnants of the enamel organ (OEE, stellate reticulum and stratum intermedium)?
Start to fuse to become the reduced enamel epithelium
What is the role of reduced enamel epithelium?
- Protection of enamel surface form
○ Resorption
○ Prevention of cementum formation- Provide an epithelial lines pathway for eruption
Form the initial junctional epithelium
- Provide an epithelial lines pathway for eruption
In what position relative to the primary tooth, is the successional lamina going to develop?
lingual
What common developmental disturbances are seen in the initiation stage?
- Anodontia
○ All teeth missing
○ Extremely rare
○ Possibly to do with PITX being formed- Oligodontia
○ More than 6 teeth are missing
○ This disturbance happens at the initiation stage
○ Something going wrong with Msx-1, Pax-9 or Axin2 in development - Hypodontia
○ One or a few missing teeth (except 3rd molars)
○ 2-10% of population
Msx-1, Pax9
- Oligodontia
- Supernumeracy of tooth/teeth (over expression of msx-1 and pax-9)
What common developmental disturbances are seen in the bud stage?
- Microdontia
○ Abnormally small teeth
○ Clinical - need to fill the space- Macrodontia
○ Abnormally large teeth
Clinical - need to do some extractions
- Macrodontia
What common developmental disturbances are seen in the cap stage?
- Dens in dente
○ Enamel organ invaginates into the dental papilla
○ Commonly affects the permanent maxillary lateral incisor
○ Get this deep lingual pit forming
○ Probably need endodontic treatment- Fusion
○ Union of 2 teeth resulting in 1 large tooth
○ Orthodontic treatment - Germination
○ Tooth germ tries to divide and you get a large single root with one pulp cavity and 2 teeth
Orthodontic treatment
- Fusion