Anomolies Flashcards
what tissues are interacting in week 6 of tooth development?
epithelium and ectomesenchyme
when is bud stage?
week 8
what stage of tooth development results in disruption that is seen on clinic?
bud stage at week 8
when is cap stage?
week 11
when do layers form in tooth development?
cap stage at week 11
when is bell stage?
week 14
what are the 5 classifications of anomalies?
quantity
size and form
formation disturbances
hereditary disturbances of structure
other
how do you differentiate developmental and environmental anomalies?
Developmental – affect all the teeth as they require the same gene expression
Environmental – will only affect teeth that were developing at the time when the environmental factor was an issue
what are the 3 quantitative developmental disorders?
anodontia/ hypodontia
hyperdontia
what is hypodontia?
missing teeth due to failing to develop
what are the 2 types of hypodontia?
anodontia
oligodontia
what is anodontia?
total lack of teeth in one or both dentitions
- no alveolar bone
what is oligodontia?
more than 6 primary or permanent teeth are absent
aetiology of hypodontia?
genetic, environmental or both
sometimes single-gene disorders
what syndromes is hypodontia associated with?
trisomy 21 (down syndrome)
ectodermal dysplasia
what do people with ectodermal dysplasia not have?
sweat glands
what are supernumerary teeth?
additional teeth
where do you find mesiodens?
midline
peg shaped teeth
what do supplemental teeth look like?
normal teeth
what is a risk associated with conical supernumeraries?
if they dont erupt they could migrate towards the nose
what skeletal dysplasia disorder may lead to supernumerary teeth?
cleidocranial dysostosis
what gene switches on and allows teeth to develop?
MSX1
what are the size and shape anomalies?
microdontia
macrodontia
dens en dente
talon cusp
what is microdontia?
one or more teeth appear smaller than normal, including peg shaped teeth
what is macrodontia?
teeth are larger than normal
what are forms of macrodontia?
double teeth
dens en dente (dens invaginatus)
talon cusps (dens envagintus)
what are the 2 causes of macrodontia?
fusion
gemination
what is fusion?
union of 2 tooth buds
what is gemination?
single root
2 crowns
what is dens en dente?
localised area where the crown is folded inwards
what is clinically important about dens en dente?
caries can lead to pulpitis and periapical infection
what are talon cusps?
adjunct cusp arises from the cingulum or CEJ in anterior teeth
what are types of structural developmental anomalies?
hereditary: amelogenesis imperfecta, dentinal dysplasia, dentinogenesis imperfecta
non hereditary: MIH, fluorosis, turners tooth
what is amelogenesis imperfecta?
defect in function of ameloblast and mineralisation of enamel matrix
what are the 2 types of amelogenesis imperfecta?
hypoplastic
hypomineralised
what does hypoplastic amelogenesis imperfecta present as?
thin but hard enamel; normal bond strength
aetiology of hypoplastic amelogenesis imperfecta?
teeth different shape before eruption
what does hypomineralised amelogenesis imperfecta present as?
full thickness enamel but soft; impaired bond strength
aetiology of hypomineralised amelogenesis imperfecta?
breakdown occurs after tooth erupts
how is amelogenesis imperfecta inherited?
autosomal dominance
what are dental defects associated with amelogenesis imperfecta?
pulp calcification
taurodontism
delayed eruption
gingival overgrowth
skeletal anterior open bite
what are the types of hypomineralised amelogenesis imperfecta?
hypocalcified
hypomature
what does hypomature AI present as?
chalky
orange/brown/white
what does hypocalcified AI present as?
enamel only persists on cervical part
what is dentinogenesis imperfecta?
autosomal dominant inherited condition
what is type I DI?
associated with osteosis imperfecta - less severe
what is type II DI?
DI on its own - more significant
what is type III DI?
“Brandywine isolate”
how is DI normally managed?
bisphosphonates
what does DI present as in the primary dentition?
amber
attrition
pulp obliteration
spontaneous abscesses
what does DI present as in the permanent dentition?
grey/translucent
short root
pulp obliteration
spontaneous abscesses
what is MIH?
developmental defect in enamel structure with less mineral content due to disruption to the maturation/ late transitional stage of amelogenesis
what teeth are most affected by MIH?
1st permanent molars and central incisors
what can MIH appear as?
demarcated enamel opacities ranging in colour
hypoplastic
breakdown of teeth
what does fluorosis arise from?
ingestion of high fluoride concentrations during amelogenesis
what is turners tooth?
area of hypoplastic enamel following infection around the interradicular area of a primary tooth
what teeth are usually affected by turners tooth?
successional tooth - often 2nd premolars
what is it called when a root has an irregular bend?
dilacerated root
