Malocclusion Flashcards
what counts as normal occlusion?
minor deviations from the ideal that do not constitute aesthetic or functional problems
what is malocclusion?
appreciable deviations from the ideal that may be considered aesthetically or functionally unsatisfactory
what is an overbite?
vertical overlap
what is an overjet?
horizontal overlap
what are the 2 occlusal classifications
angles molar classification
British standard institutes incisor classification
what is class I angles molar classification?
mesiobuccal cusp of upper 6 in line with anterior buccal groove of lower 6
what is class II angles molar classification?
mesiobuccal cusp of upper 6 anterior to anterior buccal groove of lower 6
what is class III angles molar classification?
mesiobuccal cusp of upper 6 posterior to anterior buccal groove of lower 6
what is class I incisor classification?
lower incisal edge occludes with or just below cingulum plateau of upper 1
what is class II incisor classification?
lower incisal edge lies posterior to cingulum plateau of upper 1
what is class II div I incisor classification?
overjet is increased and upper 1s normally proclined
what is class II div II incisor classification?
overjet is minimal and upper 1s normally retroclined
what is class III incisor classification?
lower incisal edge occludes anterior to cingulum plateau of upper 1
what skeletal factors cause malocclusion?
anteroposterior -> maxilla/mandible defficient/excess
vertical -> increased/decreased lower face height
transverse -> narrowed maxilla
cleft lip and palate -> class III
what skeletal factors cause postero-anterior malocclusion (class II and III)?
mandible excess or deficient
maxilla excess or deficient
what tells us if the mandible or maxilla is in excess or deficient?
cephalometric testing
what causes an increased frankfurt horizontal line?
Anterior open bite
Tongue thrust
how is increased or decreased lower face height clinically estimated?
by looking at Frankfurt horizontal plane and the line of the lower jaw. They should meet at the back of the skull
what causes skeletal transverse malocclusion?
maxilla is narrowed relative to mandible
causing cross-bite
how is a narrowed maxilla treated?
maxillary expansion
what is supernumeraries?
too many teeth
what is the most common form of supernumeraries?
conical supernumerary -> tooth between upper 1s
what is oligodontia?
too little teeth
what is the most common form of oligodontia?
upper 2s and lower 5s and 1s
what genetic condition is linked to oligodontia?
Ectodermal dysplasia
also linked to less hair and sweat glands
what is common transposition in the upper arch?
canine erupted in front of 6
what is common transposition in the lower arch?
canine erupting between 1 and 2
what is gemination?
Two teeth develop from one tooth germ
what is macrodont?
huge tooth e.g. central incisor
what is odontome?
abnormal crown morphology e.g. of a canine
what can cause loss of permanent teeth?
Trauma
Compromised teeth e.g. extra cusp
what is submergence of deciduous teeth?
Deciduous tooth fused to cortical bone, tooth progressively submerges, rest of teeth develop and the tooth becomes burried
early loss of deciduous teeth causes what?
mesial drift: e.g. E lost early, 6 drift mesially so 5 unable to erupt
what problem does retention of deciduous teeth cause?
permanent teeth unable to erupt, remove tooth, make space and expose permanent tooth
what does a tongue thrust cause?
Occlusion posteriorly but teeth don’t meet anteriorly
what is an adaptive tongue thrust?
On swallowing the tongue thrusts forward to create an anterior seal
what is endogenous tongue thrust?
tongue thrust not adapting to malocclusion
what does digit sucking do?
Proclined upper incisors
Retroclined lower incisors
what does a fleshy frenum cause?
Usually in maxillary arch and causes a median diastema
