Orthodontic Diagnosis & Treatment Planning

Question 1

What needs to be noted on a dental examination when planning for treatment?

Answer 1

All erupted teeth
Teeth of poor prognosis
Untreated caries
OH
Abnormal teeth
Trauma

Question 2

What to look for when assessing Labial segments?

Answer 2

Alignment 
Spacing 
Mild/moderate/severe crowding
Rotations or displaced teeth
Inclination
Angulation of canines

Question 3

What to look for when assessing Buccal segments?

Answer 3

Alignment
Rotation
Crowding
Spacing

Question 4

What to assess when looking at DPT?

Answer 4

Presence and position of unerupted teeth
Root form
Bone form
Apical pathology
Caries
Restorations

Question 5

What to assess when looking at upper anterior occlusal RAD?

Answer 5

Supernumerary teeth
Root resorption
Root fracture
Can also be used for parallax

Question 6

Why do we wait for the early permanent dentition 10-14 yrs for treatment (unless early interceptive tx required)?

Answer 6

• Awaiting eruption of permanent teeth before active tooth movement can begin
• Growth can be used to aid overbite reduction, AP arch correction and spontaneous tooth movement
• Pt co-operation better around early teens
• Bone remodelling in response to orthodontic forces is more rapid in children

Question 7

What is the starting point around which treatment planning can be based?

Answer 7

• The lower labial segment lies in a zone of balance
• The degree of crowding and space required needs to be assessed (if the OB is increased space will be required to level the curve of Spee)

Question 8

What is a good mental technique used before planning treatment for the upper arch?

Answer 8

- Mentally reposition maxillary canine into a class I relationship with lower canine: this will give an indication as to whether space has to be made and the type of movement required 
[crowding cases: it is usual to extract the same teeth in each arch except where extractions are planned to aid dento-alveolar compensation]

Question 9

Which scenario means the molar relationship will be purposely positioned into class II relationship

Answer 9

• If no xla planned or matched xla in both arches the molar relationship should be Class I
• If xla only in upper arch the molar relationship will be Class II

Question 10

What factors govern the choice of teeth for extraction?

Answer 10

• Amount of space required (i.e. amount of space needed to correct AP relationship)
• Prognosis of teeth
• Position of teeth
• Position of crowding and anchorage requirements

Question 11

In what scenario can you extract a lower incisor and why is long term retention needed if extracted to treat late lower incisor crowding?

Answer 11

• Only xla if poor prognosis (trauma, caries, gingival recession?
• Long term retention needed if xla to treat late lower incisor crowding as:
  1. Decrease in inter canine width and lingual tilt of lower labial segment occurs
  2. reappearance of crowding in remaining lower incisors
  3. upper inter canine width is buttressed by the lower arch and so secondary reduction in upper inter canine width and upper incisor crowding or increase in OJ may occur

Question 12

What is the tooth of choice to extract for moderate to severe crowding?

Answer 12

4s

Question 13

Indications for xla of 5s?

Answer 13

• Mild to moderate crowding
• Severe displacement
• Hypoplasia
• Congenital absence of premolar

Question 14

When is xla of 6s indicated?

When should a 6 be extracted

Answer 14

• Only when prognosis is poor and is never first choice as little space provided anteriorly for crowding relief or OJ reduction
• Good spontaneous result more likely if 6 extracted before 7 erupts
• If space required then xla of 6 should be delayed until 7 erupts and fixed appliance used for allignment
• Consider compensating xla of U6 if L6 has to be extracted
• Compensating xla of L6 avoided if U6 has to be extracted as good spontaneous result LESS LIKELY