Transverse Problem

Question 1

What is the prevalence of an anterior crossbite?

Answer 1

2.2-11.9%

Question 2

When does an anterior crossbite manifest?

Answer 2

mixed dentition

Question 3

What happens if you leave an anteiror crossbite and don’t treat it?

Answer 3

• Esthetic problem
• Damage to the teeth in crossbite through attrition
• Gingival recession
• Loss of alveolar bone on lower incisors
• Excess mobility of lower incisors affected by the crossbite

Question 4

How do you determine the differential diagnosis for anterior crossbite?

Answer 4

• cephalometric evaluation
• dental assessment
• functional assessment
• Profile analysis

Question 5

How would dental assessment help with a differential for anterior crossbite?

Answer 5

Class III molar relationship
- (+) overjet or end-to-end relationship with retroclined mandibular incisors (compensated class III malocclusion)
- If negative overjet, proceed to functional assessment

Question 6

How would functional assessment help with a differential for anterior crossbite?

Answer 6

Determine whether a centric relation/centric occlusion (CR/CO) discrepancy exists

Question 7

For a patient with an anterior crossbite…

At CR, patient may have a _____ skeletal pattern, normal facial profile and ______ molar relationship

At CO, patient may have a ______ skeletal and dental pattern

Answer 7

Class I
Class I
Class III

Question 8

What is the dental assessment flowchart?

Answer 8

Question 9

In a patient with an anterior crossbite, what will the ceph show in skeletal versus dental?

Answer 9

skeletal
- Class III maxillo-mandibular relationships
dental
- Class I or II maxillo-mandibular relationships

Question 10

In a patient with an anterior crossbite, what will the dentition show in skeletal versus dental?

Answer 10

skeletal
- Severe proclination of upper incisors
- Severe retroclination of lower incisors
- Class III molar relationship
- MAY or MAY NOT be present in Class III skeletal

dental
- Normal inclination/position or severe retroclination/retrusion of upper incisors
- Severe proclination/protrusion of lower incisors
- Class I or II molar relationship
- Presence of anterior functional shift
- MAY or MAY NOT be present in Class III dental

Question 11

In a patient with an anterior crossbite, what will the profile show in skeletal versus dental?

Answer 11

skeletal
- Concave or straight
- MAY or MAY NOT be present in Class III skeletal

dental
- Straight or convex

Question 12

The most common etiologic factor for nonskeletal/dental anterior crossbites is…

Answer 12

lack of space for the permanent incisors

Question 13

For early treatment of dental anterior crossbite, focus the treatment plan on management of the ____________________, not just the crossbite

Answer 13

total space situation

Question 14

What is the management for early treatment of dental anterior crossbite?

Answer 14

• Extraction of adjacent primary teeth to provide necessary space
• Disking of teeth
• Opening space for tooth movement
• Determine whether tipping will provide appropriate correction
• Fixed inclined planes
• Reverse crown
• Maxillary lingual holding arch with springs
• Removable appliance with jackscrew
• 2 x 4 appliance

Question 15

What is a reverse crown?

Answer 15

A large permanent anterior tooth crown is reverse-cemented

Question 16

What is a maxillary lingual holding arch with springs?

Answer 16

Lingual eruption of maxillary lateral incisors in a crowded arch

Question 17

What does this show?

Answer 17

2x4 appliance (used to treat dental anterior crossbite)

Question 18

What does this show?

Answer 18

removable appliance with jackscrew (used to treat dental anterior crossbite)

Question 19

What is the most important thing to do for early treatment of a skeletal anterior crossbite?

Answer 19

• Must refer to orthodontist
• Objective is to reduce the amount of dental compensation to skeletal; discrepancy that are often associated with a more severe malocclusion in late adolescence

Question 20

What is the prevelance of posterior crossbite?

Answer 20

• 7.3% of Hispanic population
• 9.6% in African-American population
• 9.1% among Caucasians

Question 21

What is transverse maxillary deficiency?

Answer 21

narrow maxilla relative to the rest of the face

Question 22

What is a hidden posterior crossbite?

Answer 22

Compensatory changes in dentoalveolar processes
* Tipping of maxillary teeth to the buccal
* Tipping of mandibular teeth to the lingual
* Uprighting teeth creates a dental crosbite

Question 23

What is the possible reasons for a unilateral posterior crossbite?

Answer 23

• May be a bilateral crossbite with a functional lateral jaw shift as the teeth from centric relation to centric occlusion
• Key sign: deviation of the mandibular dental midline, relative to the maxillary dental and skeletal midlines, toward the side of the crossbite when the teeth are in maximum intercuspation

Question 24

What are the possible reasons for a posterior crossbite due to functional shift?

Answer 24

1. Compensatory changes in the TMJ?
2. Modifications of soft tissue growth?
3. Development of skeletal asymmetries?
4. Attrition of teeth

No Strong Evidence

Question 25

Will a posterior crossbite due to functional shifts correct on their own?

Answer 25

NO, does not self-correct

Question 26

How do you decide the treatment for a posterior crossbites?

Answer 26

* Is the crossbite skeletal or dental? * Is the crossbite unilateral or bilateral * Is there a functional shift? * If dental, which teeth are tipped and in which jaws? * Should the treatment be initiated at this time or deferred to a later date? * Should the problems be corrected? * Can the problem be corrected or masked by treatment?

Question 27

What are the management options for a posterior crossbite?

Answer 27

* Simple dentoalveolar unilateral posterior crossbite: fixed or removable appliances to move teeth --- W-arch, quadhelix (up to age 9 or 10) --- Jackscrew: relatively heavy force that separates the partially interlocked suture

Question 28

How do you manage a posterior crossbite in early mixed dentition?

Answer 28

use slow expansion * Suture can be separated in females up to age 16, and in males up to age 18 * An occlusal radiograph is used to assess the midpalatal suture patency

Question 29

What is a buccal crossbite/scissor bite?

Answer 29

Buccal displacement of a maxillary posterior tooth, with or without contact between the lingual surface of the maxillary lingual cusp and the buccal surface of the mandibular antagonist's buccal cusp.

Question 30

What is a complete buccal crossbite (brodie bite)?

Answer 30

a combination of excessive maxillary width and a narrow mandibular alveolar process, although the width of the mandibular base is usually normal

Question 31

How do you correct a scissor bite?

Answer 31

* Elastics * Mandibular appliance to upright posterior teeth * Lip bumper