Term
| What are the three sucessive stages that every tooth develops from? |
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Definition
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Term
| What happens in the early stages of tooth development? |
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Definition
| The tooth germs grow and and expand. |
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Term
| When do the cells that differentiate into hard tissues start to differentiate? |
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Definition
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Term
| When do roots begin to form? |
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Definition
| As crowns form and mineralize. |
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Term
| What supporting tissues develop after the roots calcify? |
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Definition
- Cementum
- Periodontal Ligament (PDL)
- Alveolar Bone
•The process is the same for all teeth.
• Root formation & cementogenesis continue until these structures are fully developed. |
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Term
| Developmentally missing teeth can be from genetic abnormalities. What are two terms for developmentally missing teeth? |
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Definition
• Hypodontia
< 6 teeth missing
• Anodontia
>6 teeth missing |
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Term
| Where do neural crest cells migrate? |
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Definition
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Term
| What do neural crest cells integrate with? |
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Definition
- With dental papilla and epithelial cells of early enamel organ.
- Also function in development of salivary glands, bone, cartilage, nerves and muscles of the face. |
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Term
| What produces the dental lamina? |
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Definition
| - In jaws, neural crest cells induce the oral epithelium to produce the dental lamina. |
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Term
| Where does the dental lamina invaginate? |
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Definition
| - Into the underlying mesenchyme. |
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Term
| What two types of cells do teeth develop from? |
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Definition
• Oral Epithelial Cells (from ectoderm) will give rise to the:
-Enamel organ (forms the enamel)
•Oral Mesenchymal Cells (from mesoderm) will give rise to the:
-Dental Papilla (dentin and pulp; think: Dental Papilla=Dentin and Pulp)
-Dental Follicle (dental sac; think of the "dental sac containing the rest of the tooth parts: cementum, PDL, Alveolar Bone) |
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Term
| What are the 20 areas of enlargment that appear along the dental lamina? |
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Definition
• These are the buds of the primary teeth.
• The leading edge of the lamina will also give rise to the 20 permanent teeth that replace the 20 primary teeth. |
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Term
| What do general lamina and successional lamina give rise to? |
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Definition
•General lamina gives rise to the primary tooth buds and permanent molar tooth buds (20 each).
• Successional lamina gives rise to all permanent tooth buds except the molars. |
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Term
| When is dental lamina active? |
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Definition
- From the 6th week in utero until the person's 15th year, when the 3rd molar formation begins.
- Anterior teeth develop first
- As primary teeth erupt, the succedaneous permanent teeth development begins
• During this time the preborn child's tooth development could be interrupted by mom or child's exposure to xrays, drugs, nutritional deficiencies, and communicable diseases. |
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Term
| What does "rounded growth of epithelial cells surrounded by mesenchymal" describe? |
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Definition
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Term
| What does the cap stage consist of? |
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Definition
– Round grown becomes concave on one side
• Consists of the following:
- Enamel Organ (originates from the lamina)
- Dental papilla (originates from messenchyme to form dentin & pulp)
- Dental follicle (area surrounding the above structures, from messenchyme form: cementum, PDL, alveolar bone) |
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Term
| What is the differentation stage, and when does it happen? |
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Definition
| - During the bell stage, the enamel organ and dental papilla increase in size. This is the differentation stage. |
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Term
| What is outer enamel epithelium, when does it develop, and what does it do? |
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Definition
- During the bell stage, the enamel organ differentiates into 4 layers. This is one if the layers.
- Outer enamel epithelium covers the outer convex surface, and brings nutrition to the ameloblasts and the other enamel organ cells. |
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Term
| What is stellate reticulum, when does it develop, and what does it do? |
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Definition
- During the bell stage, the enamel organ differentiates into 4 layers. This is one if the layers.
- Stellate reticulum are cells that fill the remainder of the enamel organ. |
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Term
| What is stratum intermedium, when does it develop, and what does it do? |
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Definition
- During the bell stage, the enamel organ differentiates into 4 layers. This is one if the layers.
- Stratum intermedium are cells that lie adjacent to the inner enamel epithelium, and function with ameloblasts to form enamel. |
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Term
| What is inner enamel epithelium, when does it develop, and what does it do? |
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Definition
- During the bell stage, the enamel organ differentiates into 4 layers. This is one if the layers.
- Inner enamel epithelium defines the shape of the future tooth; these cells elongate and differentiate into the ameloblasts (enamel producing cells) by producing growth factor. |
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Term
| What are odontoblasts and when do they differentiate? |
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Definition
During the bell stage, the ou of the dental papilla differentiate into odontoblasts.
- Odontoblasts are dentin producing cells. |
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Term
| How do the general and lateral dental lamina begin to disintegrate? |
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Definition
| - Through lysis (with the exception of the posterior portion that will later give rise to the permanent molars) |
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Term
| Facts regarding the Development of Dental Papilla |
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Definition
• The young dental papilla is densely packed with cells
• It will keep pace with the growth of the enamel organ.
- The pulp cells are fibroblasts in a delicate reticulum.
- There are a few large blood vessels in the central area, with smaller ones in the periphery.
- Vascularity is necessary for growth & nourishment. |
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Term
| Where are the columnar shaped odontoblasts with cell processes that began forming during the bell stage found? |
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Definition
| On the periphery of the dental papilla. |
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Term
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Definition
- Part of the bell stage; form from growth factors to stimulate blood vessel proliferation and matrix formation.
- As crown matures produces new material/matrix. |
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Term
| Facts about partial anodontia- Iniation Stage |
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Definition
- Lack of 1 or more teeth.
- Occurs more in permanent dentition than primary teeth.
•Permanent teeth affected:
- 3rd molars
- Mx laterals
- Mn 2nd bicuspids.
• Primary teeth affected:
- Lateral Incisors |
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Term
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Definition
•Etiologies
-Familial (Occuring in more #'s of a family than by chance alone)
- Radiation therapy during tooth development
• Treatment
- Prosthetic replacement |
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Term
| When is supernumerary teeth initiation stage? |
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Definition
• 6-17 weeks in utero
- Commonly occurs between mx central incisiors distal to 3rd molars and premolar |
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Term
| When does macro/microdontia occur? |
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Definition
- During the bud stage
- Usually involves permanent mx lateral incisors and 3rd molars |
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Term
| What is a Talon Cusp/Turbercle? |
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Definition
| - Develops during cap stage, when permanent incisiors have a cingulum that projects to the height of the incisial edge; looks like an "extra cusp" on incisiors. Hereditary causes. |
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Term
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Definition
Develops during cap stage; think "twins"
- Normal # of teeth in dentition
- One pulp cavity and two crowns
- Tooth germ tries to divide
- Hereditary causes |
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Term
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Definition
Develops during cap stage
- Large tooth with two pulp cavities
- One few tooth in dentition |
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Term
| When do rounded enamel projections on the root surface in or near a furcation develop? |
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Definition
- During Apposition and Maturation Stages
- Most common is on mx molars |
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Term
| What is enamel dysplasia? |
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Definition
- Happens during Apposition and Maturation stage
- Changes in thickness of enamel
- Pitting and intrinsic changes in enamel |
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Term
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Definition
- Happens during apposition and maturation stage
- Is the union of root structure of 2 or more teeth by cementum. |
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Term
| Facts to remember about dentin and enamel |
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Definition
- Dentin lays down next to enamel in sheets
- Dentinogenesis before amelogenesis
- Basement membrane seperates the entities (D&E)
- Beginning of DEJ (Dentinoenamel Junction) |
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