Aetiology of Malocclusion - Local Causes Flashcards
what is the definition of local causes of malocclusion
localised problem or abnormality within either arch with two or several teethh producing a malocclusion
what are five factors of local malocclusion
variation in tooth number
variation in tooth size or form
abnormalities of tooth position
local abnormalities of soft tissues
local pathology
what is hypodontia
developmentally absent teeth
what are supernumerary teeth
a tooth or tooth like entity that is additional to the normal series
what are the four types of supernumerary teeth
conical
tuberculate
supplemental
odontome
what is a conical supernumerary tooth
small and peg shaped
close to the midline
tend not to prevent eruption but may displace adjacent teeth
what is a tuberculate supernumerary tooth
these tend not to erupt
paired
barrel shaped
can cause failure of permanent upper incisor eruption
what are supplemental supernumerary teeth
extra teeth of normal morphology
what are odontome supernumerary teeth
they can be compound - discrete
or complex - disorganised mass of dentine, pulp and enamel
what are retained primary teeth
a difference of more than 6 months between he shedding of contra-lateral teeth
why might primary teeth be retained
absent successor
ectopic successor or dilacerated
ankylosed primary molars
pathology
supernumerary
how should you treat a primary retained tooth with an absent successor
maintain primary tooth as long as possible if good prognosis
or extract deciduous tooth to encourage spontaneous space closure
what are infra-occluded primary molars
process where tooth fails to achieve or maintain its occlusal relationship with adjacent teeth
what are the classifications for infra-occluded teeth
slight - between occlusal surface and interproximal contact - less than 2mm
moderate - within occluso-gingival margins of interproximal contact
severe - below interproximal contact point
why might primary teeth be lost early
trauma
periapical pathology
caries
resorption by successor
what is a balancing extraction
extraction of tooth from opposite side of the same arch
minimises midline shift
what is a compensating extraction
extraction of tooth from opposing arch on the same side
maintains occlusal relationship
how should you deal with incisors being lost early
very little impact
no balancing or compensating extraction
how should you deal with early loss of deciduous canines
consider balancing extraction since unilateral loss can give centre-shift
how should you deal with early loss of deciduous molars
more space loss with Es than Ds
more space loss in the upper arch
what is macrodontia
teeth are larger than average
can cause crowding, asymmetry, aesthetic problems
what is microdontia
teeth smaller than average
leads to spacing and linked with hypodontia
what are examples of abnormal structures of teeth
peg shaped lateral
dens in dente
geminated/ fused teeth
talon cusps
dilaceration
accessory cusps and ridges
what is dens in dente
a dental anomaly where the tooth enamel folds into the dentin during tooth development
how should you manage ectopic canines
extract Cs to encourage improvement in position of 3s
retain 3 and observe
surgical exposure and ortho alignment
surgical extraction
what are causes of ectopic incisors
ankylosis of primary tooth
displacement of tooth germ
dilaceration of root
what are transpositions
interchange in the position of two teeth
what are some local anomalies of soft tissues
digit sucking
fraenum
tongue thrust
what is the main cause of median diastema
labial fraenum
how can cysts cause local malocclusions
they cause displacement of teeth and need to be enucleated
