Development and Eruption of teeth Flashcards
What are the stages of tooth development?
Thinkend band of epithelium
(2 horseshoe shaped bands one for each arch)
Initation stage 6-7weeks
Bud stage 8weeks
Cup stage 9-10weeks
Bell stage 11-12weeks
Appostions stage
Maturation stage
What is the oral epithelia cells in utro?
Ectoderm
Outer most layer of cells or tissue of an embryo in early development.
what is the mesenchymal cells?
Mesenchymal Stem Cells (MSCs) multipotent stromal cells that can differentiate into a variety of cell types, including osteoblasts.
What is the dental lamina?
The dental lamina is a band of epithelial tissue seen in histologic sections of a developing tooth.
And is the first evedence of tooth development
What is a basement membrane? What is the function of the basement membrane?
A thin, delicate membrane of protein fibres and mucopolysaccharides separating an epithelium from underlying tissue.
The primary function of the basement membrane is to anchor down the epithelium to its loose connective tissue underneath.
What does dental lamina do?
Bridge of epithelial cells connecting the enamel organ to the oral epithelium
This is regarded as the initiation stage.
What happens at the initiation stage?
What do the thickened bands give rise to?
The vestibular lamina
the dental lamina
What does the vestibular lamina do?
The vestibular lamina is responsible for the formation of the vestibule and arises from a group of cells called the primary epithelial band.
What does the Dental lamina do?
Forms tooth morphology through complex interaction between cells
Epithelial outgrows at the sites corrosponding to the future deciduous teeth
What is dentogenesis?
Initial stages of dentin formation
What is amelogenesis?
Initial enamel formation
What is apposition stage?
Formation of dental tissue matrix
What is the functional stage?
Fully erupted and loaded tooth in the oral cavity
When is pre-dentin mineralized into dentin?
In 24 hours
The enamel organ differentiates into what layers?
Outer enamel epithelium, inner enamel epithelium, stellate reticulum, and dental follicle or sac
What becomes preameloblasts?
Inner enamel epithelium
What is stratum intermedium?
2-3 cell thick layer of squamous cells
What does the presence of preameloblasts cause?
Dental papilla cells adj. to them differentiate into odontoblasts and begin to secrete pre-dentin
What results due to dentin?
Preameloblasts > ameloblasts and secrete amelogenin
What do ameloblasts do after enamel of crown is completed?
Secrete primary cuticle over new enamel
What is hertwig’s Epithelium Root Sheath?(HERS)
Is a proliferation of epithelial cells located at the cervical loop of the enamel organ in a developing tooth.
Downward growing band of cells from the root
What does hertwig’s root sheath lead to?
Cells in dental papilla next to root sheath -> differentiate into odontoblasts and secrete predentin
What happens with dentin to the inner cells of Hertwig’s root sheath?
It causes them to secrete a thin layer of cementum = intermediate cementum on dentin (always acellular)
Hertwig epithelial root sheath initiates the formation of dentin in the root of a tooth by causing the differentiation of odontoblasts from the dental papilla
What is Rests of Malassez or Epithelial rests?
Small clusters of epithelial cells that are not resorbed after hertwig’s rooth sheath breaks up
Where does the oral epithelium derive from?
Ectoderm
Where do neural crest cells derive from?
Mesenchymal cells
What are 3 types of specialized connective tissue that derive from neural crest cells?
Pulp
Cementum
Dentin
What is morphodifferentiation?
Tooth shaping; continuous process divided into different stages
What is cytodifferentiation?
Cell differentiation into specific cell types giving rise to specific tissues
What are the cell types in cytodifferentiation?
Ameloblasts
Odontoblasts
Cementoblasts
Fibroblasts
Whta do fibroblasts do?
Fibroblasts are the predominant cells of the periodontal ligament
Form pulp and PDL’s
