Card Set Information
Structure responsible for root development
Where is the cervical loop located? And what structures/cells does it consist of?
most cervical portion of enamel organ
IEE and OEE
As the cervical loop continues to grow deeper into the ectomesenchyme of the dental sac and enclosing more of the dental papilla, it forms what?
Hertwig's epithelial root sheath (HERS)
functions to shape the root (s) and induces dentin formation, so it is continueous with coronal dentin
HERS induces ___________ ____ in the root area
What induces the ondontoblastic differentiation in the roots?
Why doesn't enamel form in the roots of the teeth?
because they don't have their support structure and intermediate layers (stellate reticulum and stratum intermedium)
What happens to the basement membrane and HERS when root dentin formation is completed?
HERS root sheath disintegrates and may become these groups of epithelial cells located in the mature perio ligament. They may become cystic and cause future problems
Epithelial rests of malessez
misplaced ameloblasts migrating to the root area, abnormally forming enamel on the root surface
small spherical enamel projections found on root surface, especially at CEJ or in furcation areas on molars where root divides
How do enamel pearls appear radiographically?
enamel pearls may be confused as what? But cannot be removed.
calculus upon exploration
apposition of cementum
When does cementogenesis occur?
when HERS disintegrates allowing undifferentiated cells of the dental sac come in contact with the newly formed root dentin
What induces the cells of the dental sac to differentiate into cementoblasts?
coming in contact with the newly formed root dentin
cells of the dental sac become what type of cells when they come in contact with the newly formed root dentin?
move to cover the root dentin laying down cementum matrix
cementoblasts entrapped in the cementum
matured, calcified cementoid surrounding the cementocytes
formed as a result of the apposition of cementum over the dentin
excess cementum formation; union of the root structure of two or more teeth through the cementum only
In what teeth do concrescence usually occur?
permanent maxillary molars
as the crown and root develop, the ectomesenchyme from the dental sac begins to form the___________, and also begins to mineralize to form the _____________
alveoli of alveolar bone surrounding the PDL
The ends of collagen fibers connect in what 2 structures?
outer portion of cementum
surrounding alveolar bone
base of the crown where roots of multirooted molars and premolars originates
WHat causes the root trunk to divide into two or three roots?
differential growth of HERS
distorted roots or crown angulation in a formed tooth; results from distortion of HERS caused by injury or pressure
deviation or bend restricted to only the root portion of the tooth, usually less than 90*, may be a result of trauma to the developing tooth
extra roots or supernumerary roots; may be due to trauma, injury, or pressure affecting HERS
What teeth do accessory roots usually affect?
permanent 3rd molars, it is rare in incisors
actualy vertical movement of the teeth
occurs as we age, as gingia recedes, no actual tooth movement occurs
Do mandibular or maxillary teeth usually erupt first?
mandibular usually precedes maxillary
teeth in both jaws erupt in _____
do permanent teeth usually erupt first in boys or girls?
eruption of primary central incisors
eruption of primary lateral incisors
eruption of primary first molars
eruption of primary canines
eruption of primary second molars
tissue that covers newly formed enamel, but fuses with oral epithelium as it erupts
Reduced enamel epithelium (REE)
residue formed on newly erupted tooth consisting of the fused tissue of the REE and oral epithelium as well as the dental cuticle placed by ameloblasts on new enamel. easily removed with polishing
absorb alveolar bone between shedding primary teeth and erupting permanent teeth
cause resorption or removal of portions of the primary root of dentin and cementum, as well as small portions of the enamel crown
Why is it so important to keep primary teeth as long as possible?
they servce as place holders for permanent teeth
tendency of the permanent molars to have an eruptive force toward the midline