Interceptive Orthodontics I Flashcards
What is interceptive orthodontics?
is ‘any procedure that will reduce or eliminate the severity of a developing malocclusion’
What is the GPD’s role in interceptive ortho treatment?
knowing when to refer
Decribe what a baby’s mouth is like at birth.
Upper rounded gum pad and lower U-shaped gum pad
Often appear very class 2 and sometimes have an anterior open bite
The eruption of primary teeth happen between what period and what is the sequence of eruption?
between 6months and 2.5 years
a-b-d-c-e
Lowers erupt before uppers
What are some differences between the primary and permanent dentition? (3)
In the primary dentition:
- The incisors appear more upright
- Quite spaced
- Are more susceptible to wear as enamel is thinner
The spacing in the primary dentition can be indicative of liklihood of crowding in the permanent dentition. What is the relationship?
- No spacing = 66% will develop crowding
- <3mm spacing = 50% develop crowding
- 3-6mm spacing = 20% develop crowding
- >6mm spacing = no crowding
You can sometimes have missing or double teeth in the primary dentition. How might this impact the permanent dentition?
If have missing/fused primary teeth then might not have 2 permanent successors so missing permaent teeth
What is the early mixed dentition?
When get 6’s and incisors coming in
What are the 2 distinct stages in the mixed dentition?
- 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
Lower labial segment crowding of how much may spontaneously improve and why?
Lower labial crowding of up to 3.5mm as ger expansion/growth of the anterior part of the maxilla of up to 3.5mm
What is the ‘ugly duckling phase’?
When there is spacing between incisors, a diastema and the laterals are pointing distally
Why do lateral incisors point distally in the ‘ugly-duckling’ phase?
Can see in radiogrpahs that the permanent canines are hitting off of the dital root of the laterals causing them adopt the position
What will happen to the diastema that can be seen in the ugly duckling phase?
As the canines erupt, the diastema will disappear.
How common are diastema’s in the mixed dentition? Compare this to the % of diastemas at 12 years old
- At 6 years, 96% of people have a diastema
- At 12 years, only 7% have a diastama
Closes due to canine eruption
What size of diastema in the mixed dentition should close with canine eruption?
<2.5mm
Why is knowing the normal sequence or eruption and symmetry important?
So you can identify any abnormalities
When should a contra-lateral tooth erupt?
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
What are some reasons for problems with the eruption of upper centrals ?
- Supernumaries
- Can be blocking the path of eruption
- History of trauma/dilaceration
- Other pathology (cysts etc)
- congenitally missing
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If there is a supernumerary tooth preventing the eruption of a permanent incisor, how is it dealt with?
- 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
If there has been trauma in the primary dentition and no central incisor eruption, what would you do to assess?
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)
What might have happened to a permanent successor that has encountered trauma? How does this happen?
- dilaceration
- intrusion of the primary tooth could have damaged the developing tooth germ
What are the possible aetiologies of median diastemas?
- 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)
When might you want to take a radiograph for a median diastema and why?
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
What is leeway space?
The difference in size between the e, d, c and the 3, 4, 5
What is the leeway space normally in the maxilla and mandible?
Decidious teeth normally 1.5mm wider in the mandible and 2.5mm wider in the maxilla
What is the space required at 9 years for premolars and molars for no corwding?
18.5mm from the lateral incisor to first molar
What is balancing/compensating?
- 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
The effect of early loss of primary teeth on the permanent dentition will vary with what?
vary with the degree of crowding you have, the age you lost the tooth at (was it near exfoliation?) and the arch.
What would the management of early loss of a’s and b’s be?
- Little impact on permanent teeth
- Don’t balance or compensate
What would the management of early loss of c’s be?
Why?
- 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
What would be the management of early loss of d’s?
- Small centreline shift
- If taking teeth out under GA then may consider balancing as may help stop the centreline shift
What would be the management of early loss of e’s?
- 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)
When are first molars assessed?
At 9 years old but often will have patients with grossly arious 6’s
What are the general rules for extraction of 6’s in a class 1 occlusion?
- 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
When would you ideally think about taking out first permanent molars?
- 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
What do you need to remember about the 5’s when thinking about extracting 6’s?
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
What kind of crossbite are orthodontists concerned with and why?
Unilateral crossbites as they can interfere with mandibular closure
If there was a unilateral crossbite causing mandibular displacement, how would this be treated?
a simple removable appliance with a midline screw
quarter turn of the screw 2x a week
How long does a unilateral crossbite take to fix?
6-9months
How do anterior crossbites tend to be treated?
Treated early with an URA
Z-spring preferred
How long do anterior crossbites take to fix?
6-8 weeks
What is the stability like after correcting an anterior crossbite/posterior crossbite?
Anterior - won’t relapse
Posterior - get aout 50% relapse so over-correct in the first instance to account for this
Is a dummy sucking or thumb/digit sucking habit preferrable? Why?
Dummy habit as they tend to stop earlier (not as socially accepted)
What effects can a thumb sucking habit have on the dentition?
- Proclined upper incisors
- Retroclined lower incisors
- Asymmetric AOB or reduced OB
- Unilateral posterior crossbite
If the patient is determined to break the habit but can’t for whatever reason, what can we do?
Provide habit breaker devices
How do habit breaker devices work?
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.
If you can get the patient to stop the habit and they are under 10, what will happen?
Their teeth will erupt back into normal position within 3 years
