Interceptive Orthodontics

Question 1

Additional space if required to accommodate the larger anterior teeth of the permanent dentition. How is this achieved?

Answer 1

Leeway space
Increased in the inter canine width through lateral growth of the jaws.
Upper incisors eruption onto a wider arc- more prolined.

Question 2

What width of diastema is likely to close naturally?

Answer 2

Less than 2.5mm.

AT 6 years old, 96% of children will have a diastema.
This reduced to 7% by 12 years old.

Question 3

When would you expect the contralateral tooth to erupt?

Answer 3

Within 6 months, if not, then investigate further.

Question 4

What are the management options for an impacted first permanent molar?

Answer 4

If less than 7 years old- leave it (90% self correct).
Extract e.
Ortho separator between 6 and e- leave for 1 week and then review.
Attempt to distalise the first molar.

Question 5

What are the common reasons for unerupted central incisors?

Answer 5

Supernumeraries.
Trauma to primary tooth which has caused dilaceration of the permanent tooth.

Question 6

What aspects of history and examination would you want to undertake for someone who has an unerupted central incisor?

Answer 6

Ask patient and child if there is any history of trauma.
E/O and I/O- feel buccally and palatally for a bulge.
If retained primary incisor- look at the colour, mobility, and inclination of a’s.

Question 7

How would you manage a patient with unerupted central incisors that are caused by supernumeraries?

Answer 7

If patient less than 9 years old
- Extract primary tooth and supernumeraries.
Maintain space and monitor for 12 months.

If older than 9 years old or still fails to erupt
- expose and bond gold chain and apply orthodontic traction.

Question 8

Which teeth are required to have balancing extractions?

Answer 8

c’s and d’s

Question 9

If a patient loses their e’s prematurely, what is required to be done?

Answer 9

Maintain the space, otherwise the 6 will drift into the 5’s place and prevent it from reaching full occlusal height.

Question 10

If a patient loses their e’s prematurely, what space maintainer might you prescribe?

Answer 10

Passive URA- Labial bow or Southend clasp 3-3. Adams clasps on the 6’s.
Fixed- palatal and lingual arches or band and loop.

Question 11

When should first permanent molars be assessed for long term prognosis?

Answer 11

8/9 years old.

Question 12

When should 6’s be extracted, if required?

Answer 12

Calcification of the bifurcation of lower 7’s.
8’s present
Class 1 with an average or reduced OB
Moderate lower crowding
Mild/moderate upper crowding

Question 13

Do 6’s require compensating extractions?

Answer 13

If extracting a lower 6- also extract the upper 6 in the same side.
If extracting an upper 6, you do not need to extract the lower.

Don’t balance with sound tooth and don’t balance if well aligned or spaced.

Question 14

If you extracted a lower 6 and did not extract the upper 6, what is likely to happen?

Answer 14

Upper 6 would overerupt and prevent the lower 7 from moving medially into the space of where the 6 was.

Question 15

What are the dangers if a patient displaces their mandible during closure?

Answer 15

TMJ problems.
Permanent dentition will erupt into a unilateral cross bite.

Question 16

What is a patient’s IOTN if their mandibular displacement is greater than 2mm?

Answer 16

4c- needs treatment.

Question 17

What is a patient’s IOTN if their mandibular displacement is 1-2mm?

Answer 17

3c.

Question 18

What URA active component is suitable for a posterior unilateral cross bite?

Answer 18

Hyrax screw in the midline.

Question 19

How would an anterior cross bite be treated using a URA?

Answer 19

Z-spring anteriorly.
Adam’s clasp for retention on upper 6’s and upper central (whichever one doesn’t have the Z-spring).

Question 20

What could you do to break a digit sucking habit?

Answer 20

Positive reinforcement.
Bad tasting nail polish, wearing a glove, Elastoplast.
Habit breaker

Question 21

What types of habit breakers are available?

Answer 21

URA with a single goal post
URA with split baseplate with expansion screw and 2 palatal goal posts- active components used to correct unilateral cross bite.
Fixed appliance- tongue rake

Question 22

What are the occlusal features of a digit sucking habit?

Answer 22

Proclaimed upper incisors
Retroclined lower incisors
Localised AOB or incomplete OB
Narrow upper arch +/- unilateral posterior cross bite

Question 23

How do you know if the patient has been wearing their appliance?

Answer 23

Ask them.
Did they walk into the surgery wearing it?
Can they speak with it in?
Are they still suffering from excess salivation?
Can they take it in and out easily?
Are there any signs of wear on the appliance?
Does the palate look as though the patient has been wearing it?

Question 24

What are the potential consequences of an anterior cross bite?

Answer 24

Gingival recession
Toothwear of lower incisors
Mobile lower incisors

Question 25

For an anterior cross bite, what would you want to assess?

Answer 25

Mobility of lower incisors Toothier Gingival recession Displacement of mandible on closure- discrepancy from RC to ICP.

Question 26

Why would you want to treat a digit sucking habit early?

Answer 26

To maximise potential for spontaneous correction or anterior open bite whilst there is still eruptive potential for incisors (8-10 years old).

Question 27

What does it mean if a tooth is infra-occluded?

Answer 27

Tooth fails to reach the same occlusal height as adjacent teeth.

Question 28

How would you diagnose an infra-occluded tooth?

Answer 28

Dull percussion sound. Non-mobile Radiographs- no lamina dura present, root resorption fo primary tooth and presence.absence of a successor.

Question 29

If a tooth is infra-occluded and the permanent successor is present on a radiograph, how would you manage this?

Answer 29

Monitor for 6-12 months. Extract if primary tooth is below the contact point. Consider extraction if root formation of the permanent successor is near completion. If you extract, you must maintain the space.

Question 30

What are the dangers of doing nothing if a tooth is infra-occluded?

Answer 30

Ectopic tooth may become more ectopic. Infra-occlusion can get worse and may be inaccessible for extraction. Caries and perio disease.

Question 31

What would be the management options for an infra-occluded tooth with no permanent successor?

Answer 31

Maintain and consider onlay. Extract and maintain the space for restorative treatment. Extract and close the space orthodontically.

Question 32

if you cannot feel the buccal bulge of the canine at 11 years old, what further investigations might you wish to do?

Answer 32

OPT.

Question 33

How do canines develop?

Answer 33

Develop high and palatally, then as they start to move through bone on their eruption path, they move labial and distal to the apex of the upper laterals.

Question 34

What is the most common consequence of ectopic canines?

Answer 34

Root resorption of upper laterals- 67%.

Question 35

If we decide to extract an upper c, in the hope of an ectopic canine erupting, what factors make it likely to be successful?

Answer 35

Patient is 10-13 years old. Canine is distal to the midline of the upper lateral incisor. Sufficient space available. Canine is less than 55 degrees to the mid-sagittal plane. Likely to require a space maintainer.

Question 36

What are the management options for ectopic canines?

Answer 36

Leave alone and monitor. Extract c's and allow spontaneous reposition of canines. Extract c's and surgically expose canines for ortho traction.

Question 37

What are the risks of doing nothing if a patient has ectopic canines with retained c's?

Answer 37

Canines become more ectopic. Root resorption of adjacent teeth continues. Permanent canine fails to erupt. Root resorption of canine crown Risk of cyst formation.

Question 38

What would be the potential reasons for requesting a lateral cephalogram?

Answer 38

AP skeletal Vertical skeletal Class III incisors

Question 39

How would you assess crowding?

Answer 39

Measure space available and space required- work out discrepancy. Overlap technique

Question 40

What makes it mild, moderate or severe crowding?

Answer 40

Mild- 0-4mm Moderate- 5-8mm Severe- greater than 8mm

Question 41

What are the management options for mild crowding?

Answer 41

Stripping or extract the 5's

Question 42

What are the management options for moderate crowding?

Answer 42

extract 5's but if you get closer to 8mm discrepancy, then exact 4's.

Question 43

What are the management strategies for severe crowding?

Answer 43

Extract 4's

Question 44

What is the general rule of upper and lower extractions?

Answer 44

If you extract in the lower, you also need to take the same tooth in the upper arch. If you extract in the upper, you don't necessarily need to extract in the lower- unless class 2 molar relationship.