Malocclusions

Question 1

What makes a patient Class 1 Malocclusion

Answer 1

deviation from ideal occlusion where
Incisor overjet is 2mm to 3mm and
incisor overbite is at least 1mm (to a limit where lower incisor crown is still visible)
*canine and molar relationships no need to be in class 1
incisal relationship is most important

Question 2

What is Angle’s Class II malocclusion definition

Answer 2

Lower first perm molars distal to upper first permanent molar by at least the width of half a cusp
further divided based on maxillary incisor inclination

Question 3

What is Class II Div 1

Answer 3

maxillary anterior teeth proclined, large overjet present

Question 4

What is Class II Div 2

Answer 4

maxillary anterior teeth retroclined, deep bite

Question 5

Soft tissue appearance of Class II Div 1

Answer 5

Convex facial profile
retrognathic mandible, inceased overjet
protrusion of maxilla tends to produce acute nasolabial angle, but angle affected by nasal form itself

Question 6

Skeletal appearance of Class II Div 1

Answer 6

Protrusive maxillary/retrusive mandibular skeletal base

skeletal mandubular retrusion and shorted total mandibular length

Question 7

What’s the frequency of class 3 malocclusion in asians

Answer 7

4-14%

Question 8

Dental definition of class 3 malocclusion

Answer 8

Incisor: lower incisors edge occluded anterior to cingulum plague of upper incisors or anterior/at incisal one third of lingual surface of upper incisors

Molar angles classification: mesiobuccal cusp of upper first perm molar occluded distal to mesiobuccal groove of lower first per molar

Question 9

What is pseudo class three

Answer 9

Patients mandible postures forward from rest position to occlusion

Question 10

What if patient doesn’t have second premolar

Answer 10

Medial drift or tilt of lower molar causing dental class three

Question 11

What causes reduced sna in class 3 patient what causes increased sab in patient what happens to Anb or wits

Answer 11

Small maxilla retroposition of maxilla. Large mandible. Anterior mandible Anb lower wits more negative

Question 12

Forward mandibular rotation appearance and association

Answer 12

Appears with chin point protrusion, reduced lafh

Assoc vertically deficient maxilla

Question 13

What are the etiologies of mandibular prognathia

Answer 13

Genetics eg. Habsburg family
Environmental eg. Mandibular posture in pseudo class III patients- premature contact between incisors at CR forward displacement of mandible then occurs for closure into posterior occlusion * always check for functional shift cos you want early intervention for favourable growth

Question 14

Define dental alveolar compensation

Answer 14

Physiological
Adaptation of dento-alveolar components
In response to skeletal discrepancies
To maintain a reasonable occlusion

Question 15

What are soft tissue characteristics of class III

Answer 15

Skeletal profile straight or concave

Deficient orbital rims, deficient cheek bones

Question 16

How does a pseudo class III differ from skeletal class III

Answer 16

Pseudo class III max incisors retroclined man incisors proclined

Question 17

Why pseudo class 3 bad

Answer 17

Anterior crossbite may limit maxillary growth
Causes permanent mandibular remodeling
Gingival recession

Question 18

Effect of leeway space on class III patients

Answer 18

Mandibular primary molars are larger, thus more leeway space for man permanent 6s to drift mesially

Plus mandible grows more