Interceptive Ortho 1 Flashcards
Define Interceptive Orthodontics?
Any procedure that reduces or eliminates the severity of a developing malocclusion
What shape is an upper gum pad
Rounded
What shape is a lower gum pad
U shaped
What kind of skeletal class do most babies have at birth?
Skeletal Class 2
Sometimes AOB
When does the deciduous dentition erupt?
6mths-2.5yrs
Sequence of eruption for deciduous dentition
A-B-D-C-E
Generally lowers before uppers
Differences between deciduous and permanent teeth (3)
- Incisors more upright
- More spaced
- Wear - thinner layer of enamel so more susceptible to wear
If a child has no spacing what % will develop crowding in permanent dentition
66% crowding
If a child has <3mm spacing what % will develop crowding in permanent dentition
50% crowding
If a child has 3-6mm spacing what % will develop crowding in permanent dentition
20% crowding
If a child has >6mm spacing what % will develop crowding in permanent dentition
No crowding
List 2 issues that deciduous teeth can have?
- Absent permanent successor
2. Fused teeth
Why can fused teeth be an issue?
Patient unlikely to have 2 permanent incisors to succeed these teeth (might only have 1 when they establish permanent dentition
When do 6s erupt?
6 yrs
When do 1s erupt?
7 yrs
When do 2s erupt?
8 yrs
When do 4s erupt?
10 yrs
When do 3s + 5s erupt?
11-12 yrs
When do 7s erupt?
12-13 yrs
Features of the ugly duckling stage (3)
- Spaced upper incisors
- Diasthema
- Laterals pointing distally
How many children have a diastema at 6yrs
96%
How many children have a diastema at 12yrs
7%
What happens to a <2.5mm diastema
Should close in the transition between mixed + permanent dentition
Why do most diastemas close over by 12 yrs? (3)
- Canines come in at 11-12
- They take up more space than the deciduous canine
- They shuffle the incisors together
How quickly should a contralateral tooth erupt?
Within 6 months
List 3 reasons for un-erupted central incisors (3)
- Supernumeraries
- Trauma/dilacerations
- Hx of trauma resulting in dilacerations of the permanent tooth - Other pathology
How do we tx un-erupted central incisor supernumeraries? (4)
- Remove deciduous teeth + supernumeraries
- Expose/bond
- Create space
- Monitor (>1.5yrs)
If a patient has un-erupted 1 due to a supernumerary blocking it from erupting, what appliance would be used to fix this?
URA to tip the 2 teeth out the way and make space for the central (after the supernumerary was removed)
What % of teeth will erupt if we remove the supernumerary?
80% will erupt within an average of 16mths
What is a retained deciduous tooth?
Tooth that does not exfoliate once the permanent tooth erupts
What is a dilaceration?
Abnormal bend in the root or crown of a tooth
Implications of a severely dilacerated tooth
- Can’t straighten it or the root would appear through the labial plate –> leading to loss of vitality + extraction
Name 3 reasons for a diastema
- Small teeth
- Supernumerary
- That is not interfering with the eruption of the teeth - If you’re missing teeth
How can you get a median diastema from missing teeth?
If you’re missing a lateral then there is more space for the centrals to space out
What should you do if a patient has a big diastema and is nearly into the permanent dentition?
Take a radiograph to check if there are any supernumerary teeth in the midline
OR
Any missing teeth
List early mixed dentition interception issues (7)
- Impacted 6s
- Not come in when expected/can’t erupt as no room - Potential crowding
- Early loss of deciduous teeth
- Carious 6s
- Cross-bites
- Transposed teeth
- Habits
Define leeway space
The difference between EDC and 345
Maxillary leeway space
Deciduous 1.5mm wider than permanent
Mandibular leeway space
Deciduous 2.5mm wider than permanent
What is the minimum space required at 9yrs old for premolars and canines?
18.5mm from lateral to 1st molar for no crowding
When is a space requirement assessment carried out?
Roughly 9yrs when in mixed dentition
How is a space requirement assessment carried out?
Measure from distal of 2 to mesial of 6 (the 2 standing permanent teeth
Define balancing
in terms of early loss of deciduous teeth
If you lose a deciduous tooth on 1 side you should extract the contralateral tooth on the other side to balance
Define compensating
in terms of early loss of deciduous teeth
If you lose a deciduous tooth in the upper arch you should extract the contralateral tooth in the lower arch
What does the effect of early loss of primary teeth vary depending on? (2)
- Varies with the degree of crowding you have
2. Age you lost the tooth at
Protocol if A/Bs are lost
No balancing/compensating required
Protocol if C’s are lost
Balance
Why do C’s have to be balanced?
Because C’s hang on until the permanent incisors have erupted
- If you lose 1C theres often a midline shift towards that side
(leading to a crowded dentition)
Protocol if D’s are lost
Balance (perhaps)
Small centreline shift (not as big as C’s)
Protocol if E’s are lost
No balance
Major space loss but little effect to centreline
Why does losing an E lead to future crowding problems?
E’s can be 11mm wide or more
but the gap is reduced is by 2-4mm simply by mesial drift of the 6
This means you have much less room to fit the 3,4 and 5
What arch is mesial drift a bigger issue in?
Upper arch
How can a midline shift be tx’d in the permanent dentition
Fixed appliance
How can a midline shift be tx’d in the mixed dentition?
If patient roughly 9 and lost 1 canine
- Consider balancing with extraction
- Then the midline will naturally move back into the centre again without appliance
When is the assessment for carious 6s carried out
9yrs
What skeletal class are extractions better considered in?
Class 2 malocclusion
- Doesn’t work as well on big OJs/reverse OJs
Whats the rule if you’re extracting a LOWER 6 (2)
- Compensate upper FPM if extracting lower
- Don’t balance with sound contralateral 6
- If extracting upper don’t need to take lower
When extracting a LOWER 6 why should we compensate with the upper 6 (3)
- If you don’t take the upper 6 it will over-erupt into the space
- Impinge on the gingiva in the lower 6
- Prevent mesial movement of the 2nd molar
Why do we not need to take the lower 6 if extracting the upper 6?
Lowers don’t tend to over-erupt as much as uppers
What are some examples of when 6s should be extracted? (4)
- When the 7s furcation is present
- When 8s are present
- Class 1 malocclusion/ average or reduced OB
- Moderate lower + upper crowding
If you have a distally inclined 2nd premolar, why could this possibly cause a problem? (2)
- If distally inclined, removing the FPM can cause the 2nd premolar to drift quite significantly
Leading to unsightly spacing in the lower buccal segments - It can also impact against the erupting 2nd molar and end up bashing against it
What type of Xbite is orthodontics primarily concerned with?
Unilateral posterior crossibte as they can interfere with the way the mandible closes
If there’s a mandibular displacement on closure we would want to tx
What appliance would be used to tx a posterior unilateral Xbite?
URA with a midline screw
How is retention achieved with a URA for a posterior unilateral Xbite?
Adams clasps on 4s + 6s
How is the baseplate modified in a URA for a posterior unilateral Xbite?
Posterior bite planes
Patient instructions for a URA for a posterior unilateral Xbite
Wear it 24/7
Turn screw 1/4 1x on a Sunday + Wed
No more than twice a week
How long does it take to correct a posterior Xbite?
6-9months
Following this the patient should wear the appliance, but just inactivated at bed at night
How and when is an anterior Xbite fixed?
Tx’d with a URA
Tend to treat early - when the 2s are through
Active component for a posterior unilateral Xbite appliance
Midline screw
Active component for an anterior Xbite appliance
Z spring
Retention for an anterior Xbite appliance
Double adams clasps on posteriors
Anterior retention for anterior Xbite appliance
Adams or southend clasp (less bulky)
What can you do if you can’t get anterior retention (Adams/southend on the adjacent incisor to the z spring?)
Adams on 6s +Ds on both sides + Z spring on the central
Why do we need anterior retention?
With only Z spring + Adams on posteriors (no anterior retention) the appliance would just drop down when the Z spring is activated
What is the timeframe for a successful anterior Xbite tx?
6-8wks
Quicker than posterior
What do all posterior + anterior Xbites need
Posterior bite planes
Why do all posterior + anterior Xbites need PBPs?
The patient has to disocclude so we can push the tooth over the bite
What does the D become?
1st premolar
What does the E become?
2nd premolar
Relapse prognosis for anterior Xbite
- Won’t relapse
- -Once incisors over lower incisors the crossbite will remain corrected - Uppers might be angled forward, but they’ll be carried downwards and forwards with the lowers
Relapse prognosis for posterior Xbite
50% relapse
Which is why we over-correct
Build in relapse first so it still remains even after relapse occurs
What are some effects of thumb habits? (3)
- Can proline + push forward uppers
- Can retrocline lowers
- Unilateral posterior Xbite
What are some effects of digits sucking habits?
- Procline uppers incisors
- AOB or reduced OB
- Unilateral posterior Xbite
What appliance is used for a digit habit?
Digit habit breaker
- Connected to permanent teeth
- Cant be removed
- Double adams on posteriors
How long after a digit habit breaker should a patient break their habit?
2-3months
