Week 1 Anterior Crossbites Flashcards
True or False?
There has to be a space to move the tooth into; otherwise you cannot correct the crossbite if it is a dental cross bite
True
What is an overjet?
Horizontal distance of upper incisor ahead of the lower incisor
What is the indication of anterior crossbite?
Negative overjet
What type of anterior cross bites should we treat?
- Class 3 malocclusions with maxillary retrusion
- Class 3 with mandibular protrusion
- Those that have anterior cross bites with class 1 skeletal relationships
Do you treat patients with class 3 skeletal problems?
No
Consider treating anterior cross bites where ONLY the teeth are the problem. Not the jaws!
What is the class 3 malocclusion?
Lower molar mesial to upper molar, other teeth really don’t matter
How to determine a class 3 skeletal?
Straight or Concave profile
Molar class 3 and 0 or negative overjet
Anterior dental crossbites presents as…
Skeletal class 3 or class 1
If it is skeletal class 1, there is pseudo class 3 either max dental retrusion or mand dental protrusion
Anterior dental crossbite etiology?
Tooth bud position (ectopic eruption)
Retained primary teeth
Supernumerary tooth
Trauma or crowding
Treatment needed for anterior crossbite to tip the maxillary retroclined central incisors ?
Removable appliances
round wire, dimension 0.022, formable, springness
Treatment options for anterior dental crossbite?
- Removable appliance
2. Fixed bonded appliances
Treatment needed tipping movement and rotation of the maxillary retroclined central incisors.
Bonded fixed appliance with round wire to get the rotation.
Rectangular wire if you need bodily movement.
What kind of removable appliance is used for anterior crossbite?
Maxillary removable applaince (Hawley) with double helical cantilever
(round wire, formable, springness, dimension 0.22)
Function of double helix?
to increase the length of wire to increase range and springness, but decreases stiffness
Double vs single cantilever?
easier to adjust, further increase in wire length in constrained space
Biomechanics of Hawley with double helical cantilever?
Force applied on lingual surface of the crown
Not thru Cres (force is coronal to Cres)
Tipping force
What provides the retention in Hawley with double helical cantilever?
Adam’s clasps
Anchorage of hawley double cantilever?
Teeth (because we are moving against the teeth that are clasped)
When teeth are pushed forward, there is NO anchorage from the palate.
Why no labial bow in hawley with double cantilever?
The labial bow would be in the way since the teeth are moved forward. The labial bow would be where you want to move the teeth.
How much adjustment can be made with the hawley?
Activate spring facially and apically. Activate it 2mm. This will give you 1 mm of movement in a month.
Problems associated with Hawley?
Not activating properly
Not enough retention in the appliance
Patient compliance
How long to use Hawley to fix the problem?
should be corrected in 1-3 months if everything works well
Bonded fixed appliance material to fix anterior crossbite?
NiTi (flexible), not formable, lots of springness
Dimension: 0.014,0.016 (small) very light
Round wire
Biomechanics of Bonded Fixed Appliance?
Force applied on facial surface of crown
Not thru Cres (applied where the brackets are, when the teeth move foward, the forces will be coronal to Cres)
