Interceptive orthodontics

Question 1

What is the eruption sequence for primary dentition?

Answer 1

A B D C E
lowers before uppers

Question 2

What is primate/ anthropoid spacing?

Answer 2

Spacing mesial to upper deciduous canines and distal to deciduous canines

Question 3

When is extraction of natal/ neonatal teeth indicated?

Answer 3

If mobile and presents risk of inhalation
If causing difficulty with feeding.

Question 4

What are the 3 different phases of tooth eruption?

Answer 4

Pre-eruptive
Eruptive
Post-eruptive

Question 5

Describe pre-eruptive phase of tooth eruption

Answer 5

Starts when crown starts to form and ends when crown formation complete/ root formation about to start

Question 6

Describe eruptive phase of tooth eruption

Answer 6

Starts as soon as root starts to form and ends when the teeth reach the occlusal plane.
Split into intra-osseous - tooth moving through bone - takes months
and extra-osseous - when the tooth meets the oral mucosa (1-2 weeks)

Question 7

Describe the post-eruptive phase of tooth eruption and what PE movement occurs in response to

Answer 7

Tooth movement/ eruption continues as the root forms and throughout life in extremely small increments.

Attrition and abrasion - teeth erupt slightly to compensate for occlusal wear. Leads to MESIAL DRIFT.

In response to loss of opposing teeth - over-eruption

In response to increases in height of growing alveolar bone and jaws

Question 8

In the eruptive phase of tooth development, why do the relative position of deciduous and permanent teeth alter? e.g. what the movement occur in response to?

Answer 8

Positional changes of neighbouring crowns
Growth of mandible and maxilla
Resorption of deciduous tooth roots

Question 9

What is the gubernacular cord?

Answer 9

Fibres that are formed in the periphery of the eruption pathway, just lateral to the dental follicle.
Theory that the cord guides the teeth to erupt in the oral cavity.

Question 10

What factors cause teeth to erupt?

Answer 10

Root formation
Remodelling of alveolar bone
Development of periodontal ligament.

Question 11

How can permanent teeth be encouraged to erupt?

Answer 11

If the deciduous tooth is extracted at the correct stage (one half to two-thirds root development of permanent tooth)

Question 12

What is the definition of interceptive orthodontics?

Answer 12

Any procedure that will reduce or eliminate the severity of a developing malocclusion

Question 13

Why may lateral incisors splay in the maxilla?

Answer 13

Roots of laterals are being pressed upon by developing canines - NORMAL DEVELOPMENT
*ugly duckling stage

Question 14

What mm of space is a diastema likely to close naturally?

Answer 14

If <2.5mm, likely to close on its own.

Question 15

When is the contralateral tooth meant to erupt after eruption of the first one?

Answer 15

Expected to erupt within 6 months of contralateral

Question 16

What are the management options for impaction of FPM?

Answer 16

If patient <7years wait 6 months (90% self correct)
Orthodontic separator
Attempt to distalise the first molar
Extract E
Distal disking of the E

Question 17

What is dilaceration?

Answer 17

Deformity of a tooth that results from disturbance of the developing permanent tooth germ.
Can happen from trauma such as intrusion

Question 18

What is a balancing extraction, what is the purpose and what primary tooth is most likely to need balanced?

Answer 18

Removal of tooth from the opposite side of the same arch
Why? To maintain the position of the dental centreline (preserve symmetry)

C’s most likely to need balanced - CL is very shifted if not balanced with C’s

Question 19

What is compensating extraction and the purpose of it?

Answer 19

Removal of the tooth from the opposing quadrant
Why? To maintain buccal occlusion

Question 20

Why would you use a space maintainer for premature loss of an E?

Answer 20

To prevent mesial drift of 6 - creates crowding and can block eruption of second premolar.

Question 21

What are the general rules of extracting 6’s (in terms of balancing/ compensating)?

Answer 21

If extracting lower TAKE UPPER - do not balance if opposing tooth is sound or if arch is well-aligned/ spaced.

If extracting upper DON’T TAKE LOWER

Question 22

What are the short-term and long-term effects of NOT correcting a posterior unilateral crossbite in primary or mixed dentition?

Answer 22

Short-term - permanent dentition may develop into posterior crossbite

Long-term - if mandible is persistently displaced - can lead to TMJ problems/ disorder.

Question 23

Why do you tend to OVERCORRECT a posterior cross-bite?

Answer 23

Overcorrect as highly prone to relapse.

Question 24

What are some reasons to intercept in early mixed dentition?

Answer 24

Impacted 6’s
Potential crowding
Early loss of deciduous teeth
Carious 6’s
Cross-bites
Transposed teeth
Habits

Question 25

What is the treatment for unerupted central incisor supernumeraries?

Answer 25

• Remove primary teeth & supernumeraries
• Create space/ maintain space
• Monitor for 12 months

IF FAILS TO ERUPT

• Expose/ bond gold chain and apply orthodontic traction

Question 26

What are some examples of deterrent URA’s for digit sucking?

Answer 26

GOAL POST
Either one-piece baseplate or design alternative to include expansion (e.g. hyrax screw)

Question 27

At what age, if you are unable to palpate the canines is a radiograph indicated?

Answer 27

11