Crossbites

Question 1

Name the three local factors for Crossbites

Answer 1

1. Dental Crowding
2. Habits
3. Cleft Lip and Palate

Question 2

Most common Dental crowding for Anterior Crossbites

Answer 2

Lateral Incisors

Question 3

An early loss of deciduous second molars can cause crowding…

Answer 3

Of the permanent premolars

Question 4

What impact does habits have on the dental arch to cause crossbites

Answer 4

1. Narrow Upper arch
2. Posterior crossbites
3. Pressure applied to anterior maxilla= proclined

Question 5

What trt would be planned for a Thumbsucker for Crossbites

Answer 5

1. Digit dissuader ( removable)
2. 7/8 years old - as centrals, laterals and perm molars need to be present.

Question 6

How does a Quadhelix correct for a crossbite?

Answer 6

1.Expands Upper arch
2. Can be used as a dissuader for habits
3. Active - expands and is adjusted
4. Passive - Retention of expanded arch

Question 7

What is used for Anterior Crossbites?

Answer 7

1.Anterior expansion screws and Z springs
Creates labial movement
2. 3D Expansion screw ( expands and creates Labial movements)

Question 8

What is used for Posterior Crossbites?

Answer 8

1. Midline Screw
   2.Coffin Spring
2. 3D Expansion Screw ( Expands)

Question 9

What does a bite posterior bite plane do for Crossbites?

Answer 9

1. Props open bite
2. Stops occlusal Interference
3. Allows teeth to move

Question 10

Name two Functional Appliances used for Crossbites

Answer 10

1. Frankel Appliance
2. Clarks TB

Question 11

How does a Frankel Appliance correct Crossbites?

Answer 11

• Buccal Shields reduce the soft tissues
• Allows expansion of arch passively

Question 12

How does a Clark TB Appliance correct Crossbites?

Answer 12

• Midline screw corrects ant/post arch relationship by Expansion
• Corrects transverse relationship

Question 13

How do Fixed Appliances correct Crossbites?

Answer 13

• Torquing with rectangle wires - uprights teeth out of crossbite
  *Posterior blocks to correct ant crossbites
• Elastics - Upper = palatal to Lower = Buccal
• TMA Wires - buccal crossbites - expand arch

Question 14

How can a Lingual Crossbite be corrected?

Answer 14

• Elastics Lower= lingual to Upper = Buccal
• SS/ TMA Wires - expand lower arch

Question 15

How does Headgear correct Crossbites?

Answer 15

• The facebow creates expansion of the Upper arch
• Applied to the Intermolar Region

Question 16

What is RME?

Answer 16

Rapid Maxillary Expansion

Question 17

What happens with RME?

Answer 17

• Midline Palatal Suture Splits
• Skeletal Expansion
  *Expands and corrects crossbites

Question 18

What is the screw called on a RME and how is it used by the patient?

Answer 18

• Hyrax screw
• activated 4 x a day
• 1mm movement a day

Question 19

What Retention is needed for RME?

Answer 19

*RME left passively for 3 months
* prevents relapse and allows bony infill

Question 20

what is important in stabilising and preventing crossbite relapse?

Answer 20

• Overbite - 1/3 coverage
  *good intercuspation

Question 21

Define “Crossbite”

Answer 21

Abnormal relationship between arches
*Buco - palatal
*Buco - Lingual

Question 22

Define a Posterior Crossbite

Answer 22

BBB
Buccal cusp of the Lower
occludes
Buccally to the upper buccal
cusp
w
m

Question 23

Define a Lingual Crossbite

Answer 23

BPP
Buccal cusp of the lower cusp
occludes
Paltally to the palaal cusp of the upper teeth
w
m

Question 24

Unilateral Crossbite

Answer 24

One side

Question 25

Bilateral Crossbite

Answer 25

Both sides

Question 26

Skeletal III Crossbites..

Answer 26

* mandible = protrusive = Buccal Crossbites = Anterior Crossbites

Question 27

Skeletal II Crossbites ..

Answer 27

* Mandible is retroclined = lingual crossbites Thumbsucking = Posterior crossbites

Question 28

Narrow Maxilla Crossbites...

Answer 28

* Unilateral and bilateral crossbites * can be caused by a digit sucker = buccal crossbites

Question 29

Mandibular displacements can cause....

Answer 29

Unilateral crossbites due to displacement

Question 30

How do the soft tissues effect Crossbites?

Answer 30

*Soft tissues can create a narrow Maxilla EG, Thumbsucker, Mouthbreather - changes the positon of the tongue * Effect the balance between the cheeks and the tongue

Question 31

What is a Displacement?

Answer 31

When the mandible slides and occludes into a more comfortable position due to interference.