Orthodontic Assessment Flashcards
What is a Class I occlusion?
Maxilla is 2-3mm in front of the mandible
What is a Class II occlusion?
Maxilla more than 3mm in front of mandible
What is a Class III occlusion?
Mandible in front of maxilla less than 2-3mm
What is in a vertical skeletal assessment?
Planes angle (FMPA)
Frankfort horizontal plane and the lower border of the mandible or mandibular plane- should meet beyond the ear
If meet before the ear, increased FMPA angle
If meet well beyond the ear, reduced FMPA angle
What are competent lips?
When the lips meet at rest
What are incompetent lips?
Do not meet at rest
What can a lip trap cause?
Can procline the upper incisors
May lead to relapse of overjet if persists at the end of treatment
What effect can a tongue thrust on swallowing have on occlusion?
Can cause an anterior open bite (AOB)
Can be either endogenous or adaptive tongue thrust
May cause relapse of AOB at the end of treatment if endogenous
What are some occlusal features of digit sucking?
Proclination of upper anteriors
Retroclination of lower anteriors
Localised AOB or incomplete OB
Narrow upper arch +/- unilateral posterior crossbite
What is a Class I Incisor Relationship?
The lower incisor edges occlude with or lie immediately below the cingulum plateau of the upper central incisors
What is a Class II Incisor Relationship?
Division 1?
Division 2?
The lower incisor edges lie posterior to the cingulum plateau of the upper incisors
Division 1
–The upper incisors are proclined or of average inclination and there is an increase in overjet
Division 2
–The upper central incisors are retroclined. The overjet is usually minimal or may be increased
What is a Class III Incisor Relationship?
The lower incisor edges lie anterior to the cingulum plateau of the upper incisors. the overjet is reduced or reversed
