Orthodntic Assessment

Question 1

What is an orthodontic assessment used to detect? When is it usually done?

Answer 1

Determine malocclusion, underlying causes and if any treatment is indicated. Usually basic one at 9 and comprehensive at 11-12

Question 2

What is Andrews 6 keys?

Answer 2

Molar relationship - Distal surface of disco-buccal cusp of upper first molar occludes with the mesial surface of the mesial buccal cusp of the lower second molar

Crown angulation (mesio-distal tip)

Crown inclination sufficient to prevent over eruption

No rotations

No spaces

Flat occlusal planes

Question 3

In addition to normal history taking: MH, PDH, SH what else should be asked specific to orthodontics?

Answer 3

Any previous trauma? - can lead to root resorption or occlusal changes

Any habits such as thumb or lower lip sucking, chewing nails

Question 4

What is a class 1?

Answer 4

Maxilla 2-3mm in front of mandible

Question 5

What is a class 2?

What is div 1 and div 2?

Answer 5

Maxilla more than 3mm in front of mandible

Div 1 = increase in overjet

Div 2 = upper centrals retroclined and overjet is usually minimally increased

Question 6

What is a class 3?

Answer 6

Mandible in front of maxilla

Question 7

What angles are used to assess vertical plane?

Answer 7

Frankfort-mandibular planes angle

Frankfort line is upper and the lower is the border of the mandible line

Question 8

What should be looked for in n EXTRA ORAL EXAM?

Answer 8

Lips - competent or incompetent and lip activity. Lower lip activity can retrocline lower incisors

Habits - thumb sucking

Speech - lisping

TMJ - path of closure, ROM, clicking, displacement from ICP and RCP, if crossbite and displacement - red flag

Question 9

How can a tongue thrust on swallowing affect occlusion?

Answer 9

Often leads to an anterior open bite (AOB)

May cause relapse at the end of treatment

Question 10

What occlusal features can result from digit sucking

Answer 10

Procline of upper anteriors

Retroclination of lower anteriors

AOB or incomplete open bite

Narrow upper arch

Question 11

What would one check on Intra oral examination?

Answer 11

Oral hygiene and health of soft tissues (standard)

Count the teeth, any absent or extra?

Degree of crowding

Presence of rotations

Inclination of teeth (especially canines)

Angulation of incisors to mandibular and Frankfort plane
(Should be 110 for frankfort)

Question 12

What class of buccal segment relationship is this?

Answer 12

Class 1

Question 13

What class of buccal segment relationship is this?

Answer 13

Class 2

Question 14

What class of buccal segment relationship is this?

Answer 14

Class 3

Question 15

What should be included on the referral letter / orthodontic summary

Answer 15

• name, age and sex
• HPC, RMH, RDH
• incisor relationship, skeletal base (AP, V, T)
• teeth present or absent, OH
• lower arch incisor inclination, crowding
• upper arch incisor inclination, crowding
• overjet, overbite, centrelines, molar relationship, cross bites
• IOTN score