Occlusion Flashcards
Buccal Incisor
What is an ideal occlusion? Molar Skeletal relationship FMPA Face height
Class 1 - upper 6MB cusp occludes in the buccal groove of the l6
Skeletal relationship Class 1 -Normal profile ( antero posterior) maxilla is 2-3mm anterior of the mandible
FMPA -28 degrees
Normal face height ( Vertical) Between eyes to under nose , under nose to chin ( upper and lower FH =)
Ideal occlusion Nasio labial angle Lips Centre lines Facial assymetry
Nasio labial angle - 90-110
Competent lips
Centre lines coincident
No facial assymetry - transverse view
Ideal occlusion
Overbite
Over jet
Canine
Overbite- 1/3 lower incisor coverage
Overjet - 2-3mm
Class 1 - tip of the upper canine occludes between the lower canine and first pre molar
What are Andrews 6 keys?
Flat curve of spee/ occlusal plane
No rotations
No spaces
Class 1 molar relationship
Correct incisor crown angulation - all angled mesially
Correct crown inclination/tip-incisors angled buccal, labial, molars lingually
What are the three planes of space?
Antero posterior - Skeletal class
Vertical - facial 3rds
Transverse -horizontal ( u an l superior/inferior)
Why do you assess from 3 planes of space?
Cause of malocclusion - Genetic/environmental
To plan a realistic treatment plan
To understand what is important to patient (function/aesthetics)
To assess what is biologically possible - realistic expectations
How does extra oral assessment help in aetiology of malocclusion?
Helps assess cause
Genetic/environmental factors ( birth defects-cleft) Jaw shape ( AP)
Environmental factors- nail biting/pen chewing ( AOB increased LFH)
Crowding - ( Transverse facial assymetry)
Class 1 incisor classification
The lower incisor occludes, or lies below the cingulum plateau of the upper incisor
Class 2 Div 1 incisor classification
The lower incisor occludes posterior to the cingulum plateau of the upper incisor
The upper incisors are proclined
Class 2 Div 2 Incisor classification
The lower incisor occludes posterior to the cingulum plateau of the upper incisor
The upper incisors are retroclined
Class 3 Incisor classification
The lower incisor occludes anterior to the cingulum plateau of the upper incisor
The overbite is a two element definition
Increased /decreased
Complete/ incomplete
What is an increased overbite
The upper incisors cover more than a third of the lower incisors
What is a decreased overbite
The upper incisors cover less than a third of the lower incisors
What is a complete over bite
The lower incisors touch the upper incisors,teeth,roof of mouth, gum
What is an uncomplete over bite
The lower incisors don’t touch the upper incisors,teeth,roof of mouth or gum
What plane of space is an over jet measured
Antero posterior
What is a class 1 canine relationship
The upper canine occludes between the lower canine and first premolar
What is a class 2 canine relationship
The upper canine occludes between the lower canine and lateral incisor
What is a class 3 canine relationship
The upper canine occludes with the lower first and second pre molar
What is a class 1 molar relationship
The upper 6 MB cusp occludes in the mesio buccal groove of the lower 6
What is a class 2 molar relationship
The upper 6 MB cusp occludes mesially to the mesio buccal cusp of the lower 6
What is a class 3 molar relationship
The upper 6 MB cusp occludes posterior to the distal buccal cusp of the lower 6
What is a molar 1125
The upper 6 MB cusp is slightly anterior of the class1
What is a molar 1150
the upper 6 mb cusp is directly over the lower 6 mb cusp
What is a molar 1175
The upper 6 mb cusp is slightly posterior to the class 2 position
Transverse assessment
Buccal cross bite definition
The upper pre molar, molar is palatal to the lower pre molar/molar
Transverse assessment
Buccal scissor bite definition
The upper pre molar,molar is buccally to the lower pre molar/molar
16 reasons why a ceph is used in diagnosis
Diagnosis, aetiology of malocclusion, aid in txt plan. Assess skeletal profile Pre txt record Monitor progress Monitor growth Check for TMJ Check for fractures Check for UE teeth Check for impacted teeth Check for fractures Assess for roots Evaluate teeth movement Assess Jaw dev Anchorage loss an req Unexpected tooth movements Treatment aims being acheived
Points for Frankfort plane
Porion ( top of ear post) - Orbital (Base of eye socket)
Points for maxillary plane
ANS - PNS
Mandibular plane
Gonion - (Inferior point of mandible) - Menton (Chin)
What equation is the angle ANB
SNA-SNB Skeletal class 3 +/-3
SNA angle in degrees
Sella Nasion A Point 81 +/-3
SNB angle in degrees
Sella Nasion B Point 78 +/-3
FMPA angle in degrees
Frankfort mandibular plane angle
28 +/-4
MMPA angle in degrees
Maxillary mandibular plane
27 +/-4
UI max plane angle in degrees
109 +/-4
LI mand plane angle in degrees
93 +/-6
Interincisal angle in degrees
135 +/-10
LI - A pog
+1mm +/-2mm
What is the rickettes e line
The aesthetic line
7 limitations of a Ceph
Only suitable for Caucasions 2D image of 3D object Operator error of plotting points Pencil sharpness can intro errors in measuring angles Depd on radiograph quality/print Diff in locating points and landmarks Patient position
