Interceptive Orthodontics I

Question 1

What is interceptive orthodontics?

Answer 1

is ‘any procedure that will reduce or eliminate the severity of a developing malocclusion’

Question 2

What is the GPD’s role in interceptive ortho treatment?

Answer 2

knowing when to refer

Question 3

Decribe what a baby’s mouth is like at birth.

Answer 3

Upper rounded gum pad and lower U-shaped gum pad

Often appear very class 2 and sometimes have an anterior open bite

Question 4

The eruption of primary teeth happen between what period and what is the sequence of eruption?

Answer 4

between 6months and 2.5 years

a-b-d-c-e

Lowers erupt before uppers

Question 5

What are some differences between the primary and permanent dentition? (3)

Answer 5

In the primary dentition:

• The incisors appear more upright
• Quite spaced
• Are more susceptible to wear as enamel is thinner

Question 6

The spacing in the primary dentition can be indicative of liklihood of crowding in the permanent dentition. What is the relationship?

Answer 6

• No spacing = 66% will develop crowding
• <3mm spacing = 50% develop crowding
• 3-6mm spacing = 20% develop crowding
• >6mm spacing = no crowding

Question 7

You can sometimes have missing or double teeth in the primary dentition. How might this impact the permanent dentition?

Answer 7

If have missing/fused primary teeth then might not have 2 permanent successors so missing permaent teeth

Question 8

What is the early mixed dentition?

Answer 8

When get 6’s and incisors coming in

Question 9

What are the 2 distinct stages in the mixed dentition?

Answer 9

• 6’s at 6
• 1’s at 7
• 2’s at 8

At age 8-10 dont have many teeth lost and P stays in mixed dentition

• 4’s erupt at 10
• 3’s and 5’s at 11-12
• 7’s at 12-13

Early and late mixed dentitions

Question 10

Lower labial segment crowding of how much may spontaneously improve and why?

Answer 10

Lower labial crowding of up to 3.5mm as ger expansion/growth of the anterior part of the maxilla of up to 3.5mm

Question 11

What is the ‘ugly duckling phase’?

Answer 11

When there is spacing between incisors, a diastema and the laterals are pointing distally

Question 12

Why do lateral incisors point distally in the ‘ugly-duckling’ phase?

Answer 12

Can see in radiogrpahs that the permanent canines are hitting off of the dital root of the laterals causing them adopt the position

Question 13

What will happen to the diastema that can be seen in the ugly duckling phase?

Answer 13

As the canines erupt, the diastema will disappear.

Question 14

How common are diastema’s in the mixed dentition? Compare this to the % of diastemas at 12 years old

Answer 14

• At 6 years, 96% of people have a diastema
• At 12 years, only 7% have a diastama

Closes due to canine eruption

Question 15

What size of diastema in the mixed dentition should close with canine eruption?

Answer 15

<2.5mm

Question 16

Why is knowing the normal sequence or eruption and symmetry important?

Answer 16

So you can identify any abnormalities

Question 17

When should a contra-lateral tooth erupt?

Answer 17

Within 6 months of the first one

In pic right central incisor erupted but not left

THey also have laterals erupted before the left central incisor which should ring alarm bells

Question 18

What are some reasons for problems with the eruption of upper centrals ?

Answer 18

• Supernumaries
  
  • Can be blocking the path of eruption
• History of trauma/dilaceration
• Other pathology (cysts etc)
• congenitally missing
  *

Question 19

If there is a supernumerary tooth preventing the eruption of a permanent incisor, how is it dealt with?

Answer 19

• Remove the deciduous tooth and supernumeraries
• Expose/bond
  
  • There is debate about whether or not you should just expose the tooth or bond something to it to help it erupt (chain etc)
  • 80% of teeth that are just exposed (and space is made) will erupt within an average of 16 months
• Create space
• Monitor (>1.5 yrs)
  
  • Will erupt within 2.5-2 years

Question 20

If there has been trauma in the primary dentition and no central incisor eruption, what would you do to assess?

Answer 20

Palpate to see if you can see where the incisor has gone to and can sometimes see the incisal edge through the gingiva

Would also want to take radiographs (panoramic etc)

Question 21

What might have happened to a permanent successor that has encountered trauma? How does this happen?

Answer 21

• dilaceration
• intrusion of the primary tooth could have damaged the developing tooth germ

Question 22

What are the possible aetiologies of median diastemas?

Answer 22

• normal (small teeth)
• Supernumerary
  
  • Not interfering with the eruption of permanent teeth
  • About 10% of diastemas due to this
• Missing teeth
  
  • Missing lateral incisors then more space for the centrals to space out (in the pic)

Question 23

When might you want to take a radiograph for a median diastema and why?

Answer 23

If see one and its relatively big and patient is getting into the permanent dentition you might want to take a radiograph to check:

• There are no supernumeraries in the midline
• That they don’t have any missing teeth

Question 24

What is leeway space?

Answer 24

The difference in size between the e, d, c and the 3, 4, 5

Question 25

What is the leeway space normally in the maxilla and mandible?

Answer 25

Decidious teeth normally 1.5mm wider in the mandible and 2.5mm wider in the maxilla

Question 26

What is the space required at 9 years for premolars and molars for no corwding?

Answer 26

18.5mm from the lateral incisor to first molar

Question 27

What is balancing/compensating?

Answer 27

* Balancing – if you lose one tooth on one side, should you take out the contra-lateral tooth on the other side * Compensating – if you take a tooth out on the upper, should you take it out in the lower too

Question 28

The effect of early loss of primary teeth on the permanent dentition will vary with what?

Answer 28

vary with the degree of crowding you have, the age you lost the tooth at (was it near exfoliation?) and the arch.

Question 29

What would the management of early loss of a's and b's be?

Answer 29

* Little impact on permanent teeth * Don’t balance or compensate

Question 30

What would the management of early loss of c's be? Why?

Answer 30

* Balance * C’s hang on until the permanent incisors have erupted before they exfoliate * If you lose one c then the teeth will tend to shift to that side of the mouth (shown in pic) * If you balance then the midline will naturally fix itself * Is a bigger problem in more crowded dentitions

Question 31

What would be the management of early loss of d's?

Answer 31

* Small centreline shift * If taking teeth out under GA then may consider balancing as may help stop the centreline shift

Question 32

What would be the management of early loss of e's?

Answer 32

* Don’t balance * Major space loss * Will have significant mesial drift that will end up with a crowding problem * Upper \> lower (more space loss more quickly in the upper arch)

Question 33

When are first molars assessed?

Answer 33

At 9 years old but often will have patients with grossly arious 6's

Question 34

What are the general rules for extraction of 6's in a class 1 occlusion?

Answer 34

* If extracting the lower, take the upper out too (compensate) * Even if it has no caries and is clinically fine * The upper 6 will over-erupt and imping on the gingiva * Don’t balance with a sound tooth (treat each side separately) * If extracting the upper, don’t necessarily take out the lower * Lowers don’t tend to over-erupt as much as uppers * You want to try and avoid extraction of 6’s in a class one dentition if possible

Question 35

When would you ideally think about taking out first permanent molars?

Answer 35

* There is radiographic evidence of the 7’s furcation forming * 8’s present in radiograph (know they’ll have 2 molars eventually) * Class 1 with no skeletal element with average or reduced overbite * Mild/moderate upper crowding

Question 36

What do you need to remember about the 5's when thinking about extracting 6's?

Answer 36

That the 5 uses the root of the 6 to bump off of to guide it into place Would want to look at the 5 radiographically to see its angulation

Question 37

What kind of crossbite are orthodontists concerned with and why?

Answer 37

Unilateral crossbites as they can interfere with mandibular closure

Question 38

If there was a unilateral crossbite causing mandibular displacement, how would this be treated?

Answer 38

a simple removable appliance with a midline screw quarter turn of the screw 2x a week

Question 39

How long does a unilateral crossbite take to fix?

Answer 39

6-9months

Question 40

How do anterior crossbites tend to be treated?

Answer 40

Treated early with an URA Z-spring preferred

Question 41

How long do anterior crossbites take to fix?

Answer 41

6-8 weeks

Question 42

What is the stability like after correcting an anterior crossbite/posterior crossbite?

Answer 42

Anterior - won't relapse Posterior - get aout 50% relapse so over-correct in the first instance to account for this

Question 43

Is a dummy sucking or thumb/digit sucking habit preferrable? Why?

Answer 43

Dummy habit as they tend to stop earlier (not as socially accepted)

Question 44

What effects can a thumb sucking habit have on the dentition?

Answer 44

* Proclined upper incisors * Retroclined lower incisors * Asymmetric AOB or reduced OB * Unilateral posterior crossbite

Question 45

If the patient is determined to break the habit but can't for whatever reason, what can we do?

Answer 45

Provide habit breaker devices

Question 46

How do habit breaker devices work?

Answer 46

are only there to remind the patient that their thumb shouldn’t be there. If the patient is still doing it 2-3months down the line with these appliances, they do not want to stop and are finding a way around the appliance.

Question 47

If you can get the patient to stop the habit and they are under 10, what will happen?

Answer 47

Their teeth will erupt back into normal position within 3 years