XLAs in Orthodontics

Question 1

List 3 reasons why you may have to extract primary incisors

Answer 1

1. If they are retained and affect the eruption pathway of the permanent incisors
2. If the teeth have experienced trauma and have a poor prognosis
3. If the teeth are highly carious

Question 2

What is the most common reason to extract a primary canine in the maxillary arch?

Answer 2

To aid the eruption of permanent canines

Question 3

What can be done to aid the positioning of an ectopic permanent tooth yet to erupt?

Answer 3

Elective extraction of corresponding primary teeth

Question 4

What are some detrimental effects that can occur from the loss of primary teeth? (4)

Answer 4

1. Crowding
2. Ectopic/Impacted eruption
3. Unfavourable molar relationships
4. Centre-line shifts

Question 5

What are balancing extractions?

Why are they carried out?

Answer 5

1. A balancing extraction is a tooth from the opposite side of the same arch
2. Designed to minimise centreline shift

Question 6

What are compensating extractions?

Why are they carried out?

Answer 6

1. Compensation means extraction of a tooth from the opposing quadrant to the enforced extraction.
2. Designed to minimise occlusal interferance by allowing teeth to maintain occlusal relationships as they drift

Question 7

Is a balancing or compensation loss necessary for an early loss of primary incisors?

Answer 7

Not necessary to balance or compensate for loss of a primary incisor

Question 8

Is a balancing or compensation loss necessary for an early loss of 1st primary molars or canines?

Answer 8

Balancing extraction may be needed in a crowded arch

Compensation is not needed

Question 9

Is a balancing or compensation XLA necessary for an early loss of primary 2nd molar?

Answer 9

Balancing isnt necessary as will not affect the midline

Compensation may be necessary esepcially in a crowded dentition

Question 10

What can be used to maintain arch length and width as well as preservation of leeway space?

Answer 10

Space maintainers

Question 11

What are the functions of space maintainers (4)

Answer 11

• Maintain arch length, and width- preservation of leeway space
• Prevent over-eruption of opposing teeth
• Improve aesthetics (anterior segment)
• Aid in the management of oral habits (prevention of digit sucking)

Question 12

Describe an ideal space maintainer

Answer 12

• Simple
• Durable, strong and stable
• Passive and not causing orthodontic changes to other teeth
• Cleansable and not increasing the risk for caries development

Question 13

What type of space maintainers are these?

Answer 13

Unilateral Space Maintainer

Question 14

What are the specific names of these unilateral space maintainers?

Answer 14

A) Band and Loop

B) Band and Loop

C) Distal Shoe

Question 15

What is the type and name of this space maintainer?

Answer 15

Type: Fixed Bilateral

Name: Lingual Arch

Question 16

What is the type and name of this space maintainer?

Answer 16

Type: Fixed Bilateral

Name: Nance Palatal Arch

Question 17

What is the type and name of this space maintainer?

Answer 17

Type: Removable Bilateral

Name: Upper removable appliance

Question 18

What may be an indication of a lower lingual arch space maintainer?

Answer 18

Loss of several posterior teeth and lower first permanent molars (6s) have erupted

Question 19

If a patient has poor OH and need a space maintainer for the upper arch what should be used?

Answer 19

Upper removable appliance

Question 20

When determining the consequences of premature primary tooth loss what are the 3 key factors to consider?

Answer 20

1. Degree of crowding
2. Type of tooth loss
3. Age of the child

Question 21

When making a decision to extract a tooth for orthodontic treatment what should be considered? (4)

Answer 21

• Degree and site of crowding
• Type of malocclusion
• Presence and position of teeth
• Dental health of teeth

Question 22

A paeds patient has a grossly carious lower 6 which you will XLA.

You decide the opposing 6 should also be extracted. How would you justify this to the patient/parent to gain their consent?

Answer 22

Explain that whilst the opposing 6 is healthy, there are benefits to it being removed
* If it is not removed, it will over erupt and lead to occlusal disturbances. It will prevent the forward moment of the lower 7 which you want to take place of the 6. This can lead to a localised space
* If the opposing tooth is not extracted then you will loose the class 1 molar relationship. This will disturb the inter arch relationship
* Explain that maxillary spaces are closed more rapidly. The 7 will drift and close the space
* Explain that the 8 is radiographically present. In most patients, 8s are non-functional and are removed due to the arch being too short to accommodate them. However, with the 6 being removed and the 7 drifting forward, the 8 can therefore make up for the lack of teeth in a few years time
* Removing the 6 may also provide relief of buccal crowding