PAEDS - dental anomalies Flashcards
when do teeth begin to develop?
6 weeks IUL
what are the stages of tooth development?
initiation - dental lamina
morphogenesis - bud and cap stage
cell differentiation - bell stage
matrix secretion - eruption
what is formed at cap stage?
enamel knot
what is amelogenesis regulated by? and what are the 3 phases?
ameloblasts
- secretory phase
- calcification phase
- maturation phase
what regulates dentinogenesis?
odontoblasts
what is the term used to describe an anomaly of tooth number in which there is developmental absence of primary or permanent teeth?
hypodontia
what is another name for severe hypodontia?
oligodontia - more than 6 teeth absence (excluding third molars)
what stage of development is interrupted to result in hypodontia?
initiation stage
what is the genetic aetiology of hypodontia?
single gene defect - MSX1
what syndromes may have hypodontia as a feature?
ectodermal dysplasias
trisomy 21
cleft lip and palate
solitary median maxillary central incisor syndrome
what environmental factors may cause hypodontia?
sequela of severe disease and cancer tx early on in childhood
list the order of most commonly teeth affected by hypodontia?
lower 5
upper 2
upper 5
lower 1
list clinical features of hypodontia?
failure of primary tooth to exfoliate at expected time
permanent tooth hasnt erupted several months after primary exfoliates
teeth erupt out of sequence
contralateral tooth has been erupted for more than 6 months
teeth appear unusually spaced
primary teeth become infraoccluded
high association with microdontia
association with ectopic teeth
no tooth palpable in the buccal or lingual/palatal sulcus
how is a hypodontia diagnosis confirmed?
radiograph (PA first)
DPT if PA doesnt show enough
what is the multidisciplinary approach for managing hypodontia?
diagnosed by GPD
referred to paeds or ortho depending on age and stage of development
seen in secondary care by paeds, ortho, and restorative
why is OHI paramount for patients with hypodontia?
fewer teeth so ones that remain must be caries free as the patient is likely to undergo ortho and may require a prosthesis
what does treatment for hypodontia involve?
space redistribution, tooth modification and prosthetic replacement
what is cleidocranial dysplasia?
autosomal dominant disorder
- clavicles dont form
- primary teeth dont exfoliate on time
- permanent teeth delayed eruption
- loads of supernumeraries
what is ectodermal dysplasia?
a group of diseases affecting the structures arising from the ectoderm:
- teeth
- hair
- nails
- sweat glands
- salivary glands
what is the most common type of ED?
x-linked hypohydrotic ectodermal dysplasia
what are characteristics of ED?
sparse hair
dry skin
inability to sweat
may also suffer from xerostomia, dry eyes and nasal congestion
what do the teeth of patients with ED present as?
conical appearance
microdontia and hypodontia of multiple teeth
what is the dental anomaly in which there is addition of a tooth/teeth to the normal sequence?
supernumerary teeth
what stage of development do supernumerary teeth form at?
initiation stage
what is the aetiology of supernumerary teeth?
genetic, often runs in families
what syndromes do supernumerary teeth tend to present in?
cleidocranial dysplasia
cleft lip and palate
gardner syndrome
what is the prevalence of supernumerary teeth?
<1% primary dentition
35-50% permanent dentition
M>F
how can supernumeraries be defined?
position; mesiodens, paramolar
shape; conical, tuberculate, supplemental, odontome
what are the most common shapes of supernumerary teeth?
conical
what types of supernumerary teeth are likely to erupt ?
likely to erupt:
conical (if not inverted)
supplemental (particularly incisors)
not likely to erupt:
tuberculate
odontomes
where do you commonly find conical supernumerary teeth?
midline maxilla
often in pairs
often inverted
what teeth are usually supplemental?
lateral incisors
3rd premolars
4th molarsw
what is an odontome?
collection of tooth tissue
compound: denticles
complex: disorganised collection of tooth tissue
likely to impede eruption of nearby teeth
what is the first sign of a supernumerary?
eruption of the supernumerary
delayed eruption of the normal sequence
what are the effects of supernumerary teeth?
crowding +/rotation, malposition, ectopic position of surrounding teeth
common cause for delayed eruption of central incisors
what is the clinical examination for supernumerary teeth?
palpate for the presence and position of unerupted teeth
what is management for supernumeraries?
monitor
simple xla
surgical xla
teeth which have been impeded may need to be surgically exposed +/- ortho repositioned