Orthodontic Assessment Flashcards
when is orthodontic assessment usually carried out
9 years old - mixed dentition stage
what is Andrew’s six keys
definition of the optimal occlusion in permanent dentition
what are the six keys in andrew’s six keys of occlusion
molar relationship
crown angulation
crown inclination
no rotations
no spaces
flat occlusal planes
what is the first key in Andrew’s six keys
molar relationship - distal surface of disto-buccal cusp of the upper FPM occludes with mesial surface of the mesio-buccal cusp of the lower second molar
what is the second key in Andrew’s six keys
crown angulation - the gingival part of the long axis of the crown is distal to the incisal part of the axis
what is the third key in Andrew’s six keys
crown inclination - incisors at sufficient angulation to prevent over-eruption, upper posteriors lingual tip is constant and similar from canine backwards, lower posteriors lingual tip increases progressively from canines back
what is the fourth key in Andrew’s six keys
rotations are not present
what is the fifth key in Andrew’s six keys
there are no interdental spaces
what is the sixth key in Andrew’s 6 keys
there is a flat plane of occlusion
what is the difference between normal and ideal occlusion
normal occlusion is more common and incorporates minor deviations that do not constitute aesthetic or functional problem
what are malocclusions
significant deviations from the ideal that are unsatisfactory aesthetically or functionally
what is a tongue thrust
reverse swallow or immature swallow - the tongue protrudes anteriorly or laterally when swallowing, during speech and when the tongue is resting
what are the three planes facial skeletons are considered in
Anterio-posterior (AP)
vertical
transverse
what are the three classes of occlusion depicted in the AP plane
class I
class II
class III
what is a class I occlusion in the AP plane
maxilla is 2-3mm infront of mandible
