disorders of tooth formation Flashcards
what may cause disorders of tooth formation?
-genetics
-local and systemic factors
what disorders cause missing teeth?
-hypodontia
-anodontia
what is hypodontia?
when teeth fail to develop- commonly permenant 8s, 5s, upper 2s
what is anodontia?
total lack of teeth
who is most likely to experience hypodontia of permanent dentition?
those who were missing primary teeth (30-50%)
what is the treatment for hypodontia?
partial dentures
implants
what can be present with missing teeth?
small teeth
what is advised for small teeth?
composite to shape teeth
what disorder is known as extra teeth?
supernumerary or hyperdontia
who is more likely to experience supernumerary?
males 2:1 females
people with primary supernumerary are 30-50% more likely to experience…
supernumerary of the permanent dentition
where are supernumeraries more likely to appear?
maxilla 5:1 mandible
where are supernumeraries normally found?
mesiodens- midline of anteriors (maxilla) or directly adjacent to midline
paramolars- buccal or palatal side of maxillary molars
distomolars- distal to maxillary 3rd molars
what may cause supernumerary?
idiopathic (unknown cause) but may be associated with syndromes such as cleidocranial dysplasia
what is megadontia?
larger crown size than normal
who is likely to experience megadontia?
those with pituitary giantism where all teeth are larger than normal
what is microdontia?
smaller teeth than normal
what teeth are commonly affected in microdontia?
-maxillary lateral incisors
-maxillary third molars
what shape are microdontia lateral incisors?
peg/conical shaped
what shape are microdontia 3rd molars?
same shape but smaller
who is more likely to experience microdontia?
females
what syndromes are more likely to be affected by microdontia?
-down syndrome
-ectodermal dysplasia
name 3 things that may affect root size?
-oriental origin-smaller roots
African origin -larger roots
-Orthodontics
-irradation of jaw or chemotherapy during root formation may cause smaller roots
who plays a role in disorders of tooth formation treatment?
-paediatricians
-orthodontist
-restorative dentist
what is gemination?
disorder that results in double teeth with one root canal
what causes gemination?
attempt at developmental separation of single tooth germ to produce separate teeth
what teeth are most commonly affected by gemination?
anteriors and decidious teeth
what is tooth fusion?
double teeth with 2 root canals
what causes fusion?
joining of two separate and adjacent tooth germs during development
what teeth are commonly affected by fusion?
deciduous teeth and may happen between one tooth and a supernumerary
define concrescence
-joining of two teeth by cementum at the root surface (may be with a supernumerary)
what may cause concrescence?
-overcrowding
-trauma
-roots in close proximity during development
what teeth are most commonly affected by concrescence?
maxillary molars
define dilaceration
gross disruption of root formation- where root forms at an angle which can impede tooth eruption
what causes dilaceration?
thought to be trauma to tooth germ during root development
how is dilaceration identified?
radiographically
what are invaginated teeth?
normal shaped teeth with an infolding on the palatal/lingual surfaces-forming deep pit of the cingulum
what is invagination of teeth also known as?
dens in dente
how is invagination seen on a radiograph?
pear shaped mass of enamel seen in dentine of involved tooth
who and where is invagination most common in?
permanent maxillary lateral incisors
-often those with Chinese ethnicity
-males
how do you treat invaginations?
-fissure seal as soon as erupted
-check vitality
-endodontic tx if pulp involved
define evaginated teeth
small tubercle on occlusal surfaces of premolars in central part of fissure pattern- commonly worn down or fracture by normal wear
what ethnic group are likely to experience evaginated teeth?
Chinese
what treatment may be needed for evagination?
-radiographs to check pulpal horn involvement in evagination
-fissure sealant if worn
-pulpotomy
what are talon cusps?
projections on the cingulum of maxillary incisors
what is the tx for talon cusps?
-fissure seal
-pulpotomy if pulp chamber involved
-no treatment if occlusion ok
what is taurodontism?
teeth with enlarged pulp chambers in a vertical direction- permanent 1st molars commonly affected
what factors cause amelogenesis and dentogenesis?
genetics
what is amelogenesis imperfect? name two forms
disorders that lead to defective enamel of primary and permanent teeth.
hypoplasia
hypomineralisation
what is enamel hypoplasia ?
-can result due to febrile illness
-cause defective enamel form or colour
-due to destruction or damage of ameloblasts during enamel matrix formation.
what are the symptoms of enamel hypoplasia?
-horizontal rows of pits on enamel surface
-glossy enamel
-thin enamel- translucent
what is hypo mineralisation?
-defects in the mineralisation of enamel making it soft and discoloured/opaque/chalky
what is the risk of hypomineralisation?
prone to caries and fractures
how are localised enamel defects managed?
simple restorative procedures- e.g affected molars- SSC
what will likely be seen with more generalised amelogenesis imperfect?
-aesthetic concerns
-sensitive patients
-sensitive to thermal/mechanical stimuli
-poor OH/staining
what is dentinogenesis imperfect?
inherited disorder affecting dentine- which may or may not be associated with osteogenesis imperfect (collagen disorder)
what does dentogenesis imperfects look like?
-opalescent teeth-that are grey/brown
is the enamel affected?
no enamel structure is normal- but likely will flake off due to poor adhesion to dentine
how does dentogenesis imperfect affect primary over permanent?
-likely cause pulpal exposure in decidious teeth
-permanent are less severely affected
how do you manage dentinogenesis imperfect ?
-if localised- restorative tx e.g crown molars
-if generalised
can affect:
-aesthetic concerns
-sensitive patient
-sensitive to thermal/mechanical stimuli
-poor OH
what infection can causes tooth disorders?
congenital syphillis
what causes congenital syphillis?
spirochete treponema pallidum found in dental follicle
how is congenital syphillis transmitted?
via placenta
what 3 disorders does congenital syphhillis cause?
-hutchisons incisors
-mulberry molars
-moons molars
what does hutchisons insciros cause?
-notches in upper incisors
-mesio-distal narrowing of incisor edge
-may leave anterior open bite
what does mulberry molars cause?
-rough and pitted occlusal first permanent molars
-nodules instead of cusps
-resembles mulberry
what does moon molars cause?
-round/dome shaped 1st permanent molars
what is an enamel pearls?
small spherical enamel projection on cementum of root
-most commonly on buccal root surface close to bifurcation
-caused by ameloblast displacement during enamel formation
-often mistaken for calculus
