Tooth abnormalities Flashcards
Enamel oringinated from
Ectoderm
Dental papilla originated from
mesoderm
What is dental papilla
dentin and pulp
What is the dental sac
cementum
periodontal ligament
alveolar bone
where did the dental sac originate from
mesoderm
What is the dental lamina
region where the teeth form- defined by an epithelial thickening
What are the 4 different stages of tooth maturation
bud stage
cap stage
bell stage
crown or maturation tage
What is the bud stage
Dental lamina differentiates and tooth buds appear on the dental lamina in the approximate location of the 20 teeth
What is the cap stage
When the round form of the tooth bud is altered and the basal portion invaginate and the structure takes the form of a cap
What is the bell stage
deepening of the concavity of the cap formation
When is most of the enamel and dentin formed
during the bell stage
What is the crown stage
hard tissue develops
What do ameloblasts makes
enamel
When do ameloblasts die
when teeth erupt
Can we make more enamel once our teeth have erupted?
no
What do ondontobasts make?
dentin
Can we make dentin after tooth eruption
yes
The splitting of a single tooth bud results in…
gemination
What tooth most commonly undergoes gemination
incisors
What are the two types of gemination
incomplete and complete
Define incomplete gemination
two crowns with a common root and pulp chamber
Define complete gemination
two identical teeth individual teeth next to one another
Union of two adjacted tooth buds results in…
Fusion
Fusion is two teeth being… together
fused
T/F: Fusion can only involve the crowns, not the roots
F can involve only crowns or both crowns and roots
Define Concrescence
The union by way of the cementum of the roots of two or more teeth
When does concrescence normally occur
after eruption
Concrescence is most commonly found in what teeth
molars (especially maxillary where the roots are within close proximity to adjacent teeth)
T/F: Concrescence can not occur between crowns of teeth
t (crowns do not have cementum)
What actions result in dens in dente
results from infolding of the enamel organ whereby dentin and enamel become reversed inside the pulp chamber
How are most cases of dens in dente treated
with root canal treatment
What does dens in dente look like radiographically
appears as a small tooth inside another tooth
What tooth is dens in dente most commonly seen
permenant maxillary lateral incisors
How do supernumerary teeth (accessory) teeth arise?
the result from extra tooth buds on the dental lamina- considered genetic
T/F: Deciduous dentition can not develop supernumerary teeth
F (can occur in both sets)
Define a mesiodens
a supernumerary tooth found at the midline of the palate between the maxillary central incisors
What is distodens
Supernumary tooth found distal to the third molar
Define Anodontia
lack of teeth
What are the two types of anodontial
total and partial
Define total anodontia
A large number or all of the teeth are missing (Teeth didn’t form)
Define partial anodontia
One or a few teeth don’t form
Is anodontia genetic?
yes
Can anodontia occur in deciduous dentition
yes-but unlikely
Most common tooth impacted by anodontia in deciduous teeth
mandibular central incisor
Most common teeth influenced by anodontia in permanent dentition
- 3rd molar
- Maxillary lateral incisor
- Mandibular 2nd premolar
Define pseudoanodontia
Large number of teeth have not erupted but have all formed (are impacted)
Define impacted
Teeth that either partially erupt or do not erupt at all.
Common reason why teeth become impacted
obstruction
Tooth that is most commonly impacted is
third molars
Define transpostion
When teeth are out of place (i.e first premolar is mesial to a canine v.s distal to it)
Define neonatal teeth
Deciduous teeth present at time of birth
What is microdontia/macrodontia
Teeth are smaller/bigger than normal
What are the two types of macro/microdontia
true and false
define true macro/microdontia
All teeth are abnormally large or small
Define false micro/macrodontia
individual teeth are large/small
Microdontia is a result of
pituitary dwarfism
Macrodontia is a result of
pituitary gigantism
What is a peg tooth
A tooth with incomplete crown formation
What tooth is most commonly seen as a peg tooth
maxillary lateral incisors
Other teeth seen as peg teeth may be…
premolars
What lobes develop in peg teeth and which ones do not?
Do- The lingual and middle
Don’t- Distal and mesial
What is a talon cusp
Extra enamel projection on a crown
Where is a talon cup most often seen
most often seen on the cingulum
what tooth is commonly seen with talon cusps
maxillary lateral incisors
T/F A talon cusp can not contain a pulp horn
F- they can
What is an enamel pearl
small spherical nodule of enamel surrounding dentin core
Where do enamel pearls attach
to the roots of molars- most commonly at the furcation area
What issues can an enamel pearl lead to
periodontal problems
Why must you be careful when grinding away an enamel pearl
they may contain pulp horns
Taurodontia is characterized by…
pulp chamber that’s very long without a constriction at the CEJ
T/F: Taurodontia only occurs in permanent teeth
t
Name two different distortion of tooth formation as a result of traumatic injury or pressure on developing teeth
flexion and dilaceration
Define flexion
Occurs when injury happens later in development and the distortion (bending) is only found in the root
Define dilaceration
Occurs earlier in development Distortion (bending) in both crown and root
How can tetracycline stain happen
by taking the antibiotic tetracycline during the time of teeth formation
What part of the tooth does the antibiotic tetracycline stain?
Dentin
Define enamel hypoplasia/enamel hypocalcification
Dysplasia of enamel due to a disturbance at the time of enamel formation
What is amelogenesis imperfecta
dysplasia (lack of) enamel-
Is amelogenesis imperfecta genetic?
Yes
What is the cause of amelogenesis imperfecta
faulty ameloblasts
Consequences of amelogenesis imperfect
teeth are anesthetic, easily worn down, and prone to rampant decay
What is dentinogenesis imperfect
genetic disturbance of dentin formation resulting in bluish brown anesthetic crowns, little or no pulp chambers form
Whey are those with dentinogenesis imperfect prone to fracture
because the enamel is under poor dentinal support
What is ectodermal dysplasia
genetic condition resulting in defective formation of ectodermal structures
What is Cleidocraniodysostosis
defective formation of membrane bones (bones of skull, clavicle, and mandible)
What bones will not be affected by Cleidocraniodysostosis
bones with a cartilagenous precursor
What is odontoma
a benign tooth tumor
What tissues includes odontoma
ectodermal and mesodermal
How does odontoma arise
infection or trauma disturbing the dental lamina
What are found in the odontoma tumors
enamel dentin and cementum
What are the two types of odontoma
Complex and compound
Define complex odontoma
One mass of calcified dental tissues without recognizable tooth form attached to a tooth or located separately in alveolar bone
Define Compound odontoma
calcified dental tissue that is arranged in recognizable tooth forms
