Developmental and Acquired Anomalies of Teeth Flashcards
what are the 7 stages a tooth goes through?
initiation
proliferations
histodifferentiation
morphodifferentiation
apposition - enamel and dentine are deposited
calcification
eruption
when does the incisors initial calcification occur?
3/4 months in utero
when does the crown completion occur for primary teeth?
4 months after birth
when do the first lower incisors erupt?
around 6 months
when do the roots complete for primary teeth?
18 months after eruption
for permanent teeth, when do the first molars develop and when do they calcify?
develop at 4 months in utero
calcify at birth
when do the central incisors and lower laterals develop?
3-4month
when do the upper laterals develop?
10-12 month
how can you classify an anomaly?
developmental
acquired
descriptive - structure, number, size and shape, eruption and exfoliation
how are enamel anomalies classification?
qualitative defect
- hypomineralisation/calcification/maturation
quantitative defect
- hypoplastic - underdevelopment (pitting)
congenital
genetic
acquired - can be local/systemic insult
idiopathic
what is the different between hypo plastic and hypo mineralised?
stage?
- plastic = secretory stage
mineralised = post-secretory stage
deficiency?
- plastic = deficit in the thickness
mineralised = lack of mineral
prior to eruption
- plastic - enamel is missing
- mineral - has the enamel
plastic are slow changes, mineral has fast changes
amelogenesis imperfecta
- aetiology
genetic disorder
affects amelogenesis
- affects the enamel formation
- disrupts the ameloblasts
what is Witkop’s Classification
a classification for amelogenesis imperfecta
Type I = hypoplastic
Type II = hypomaturation
Type III = hypo calcification
Type IV - hypomature/hypoplastic + taurodontism (pulp chamber is large vertically)
dentinogenesis imperfecta
- aetiology
- 3 key features
- 3 types
autosomal dominant inherited condition
- defective dentine
looks like:
- short roots
- grey/blue colour
- cervical constriction
DI
- associated with osteogenesis imperfects
DI I
- mutations of gene
DI II
- mutations of gene
Dentine Dysplasia
normal looking crowns but defective roots
Type I
- clinically normal but sharp, conical apical constriction
Type II
- abnormal primary teeth
but normal permanent teeth
- translucent amber teeth
- look ‘rootless’
- thistle shaped pulp chamber
MIH
hypomineralisation of systemic origin
- affects 1+ permanent molars
- freq associated with incisors
Fluorosis
may look like amelogenesis imperfecta
an excess increase in fluoride intake during development
- need a good family history
Hyperdontia
- epidemiology
- how are they classified?
excess teeth
usually in the permanent teeth
more males>females
more in the maxilla>mandible
classification
the position
- mesiodens - in the midline
- paramolars/distomolars - by the molars/behind the molars
by shape
- supplemental - normal
- conical
- tuberculate
- odontomes - complex or compound
what 3 conditions can supernumerary teeth be associated with?
gardener syndrome - polyps in the colon and rectum
oral facial digital - affect developmental of oro-facial
cleidocranical dysplasia
Hypodontia
- in order of most common
- what genetic mutations can this be from?
missing teeth, more common in female
Witkop syndrome - mut of MSX1
missing molars - PAX9
hypo/oligo - Trisomy 21
- 8
- L5
- U2
- U5
- L1
define anodontia and oligodontia
anodontia - a complete absence of teeth
oligodontia - 6+ teeth are absent
Ectodermal Dysplasia
disorder of the ectoderm
- affects teeth, hair, skin, nails and sweat glands
how can a double tooth occur?
fusion - two single tooth germs have fused
gemination - single tooth germ has split into two teeth
what is concrescence?
fusion of the cementum
