Managemment of the permanent dentition

Question 0

The removal of teeth to create space in mild crowding (

Answer 0

1) Molar distalisation.
- Moving first molars distally can create space. Technically difficult in Md but possible in Mx and appropriate for mmild crowding (bucccal segment relationship up to 1/2 a unit class II)
- The most predictable technique is using extraoral traction with the use of headgear
2) Maintainence of leeway space
- Me-di width of E’s are more than 5’s.
- Done by holding the position of the 6’s with a lingual arch and banding just prior to exxfoliation of thhe E’s
3) Lip bumper
- Md fixed appliance that keeps the lip and cheek pressure from the lower anterior teeth.
- Uprights and distally moves lower molars, forward movement of lower incisors and some transverse arch expansion
4) Interproximal enamel reduction
5) Active arch expansion

Question 1

With moderate crowding (5-8mm), extractions are usually required. They are based on the position of the crowding and anchorage requirements to achieve treatment aims. How does this determine which teeth to extract?

Answer 1

If theres an increased overjet as well as crowding, the removal as far forward in the arch as possible (4’s).
If incisor retraction is undesirable, 5’s should be extracted.
If timed, properly, ideal alignment can be achieved without orthodontic treatment i.e. removal of 4’s as canines erupt. Mesiolly angulated canines in the mandible can upright and hence save space.

Question 2

The main cause of spacing in the dental arch is a discrepency between tooth size and arch length. What are some of the underlying causes of this?

Answer 2

Localised or generalised microdontia, hypodontia and increased jaw dimension.

Question 3

One of the commonest manifestations of a tooth size- arch length discrepency is a midline diastema. How can these be managed?

Answer 3

Fixed appliances normally required to close the space possibly with some buildup on the adjacent teeth if they are small

Question 4

The two main treatment options for localised hypodontia is space closure or space opening and maaintainence for prosthetic replacement. How is this applied for a missing Mx lateral incisor?

Answer 4

1) Class I cases if the lower arch is crowded, consider extraction of lower premolars and space closure of the uper arch substituting upper laterals with canines.
2) Class II, space from missing teeth can be used to reduce the overjet and correct incisor relationship
3) Class III, space closure will retract the upper labial segment making the malocclusion worse. Better to leave open space.

Question 5

The two main treatment options for localised hypodontia is space closure or space opening and maaintainence for prosthetic replacement. How is this applied for a missing Md second premolar?

Answer 5

If space is required to relieve crowding, retained E’s should also be removed and space closed.
In the absence of crowding, space closure may lead to over-retraction of the labial segments. If the E has a good long term prognosis, can be retianed.

Question 6

An increased overjet is associated with a class II malocclusion. What are the two options for its reduction?

Answer 6

1) retraction of upper labial segment

2) advancement of lower labial segment

Question 7

A class II malocclusion is usually associated with a class II dental base relationship involving a maanddibular retrognathia. How should this be managed?

Answer 7

Orthodontic tooth movement alone is insufficient to correct this.
Treatment aimed at encouraging favourable growth should be considered in a growing child with a skeletal discrepency using a functional appliance or headgear.

Question 8

What are the various ways in which the mechanotherapy for reeducing an overjet can be carried out?

Answer 8

1) Removable appliances
2) Functional appliances
3) Fixed appliances
4) Orthoggnathic surgery

Question 9

How can removable appliannces be used to correct reduce an overjet?

Answer 9

If the upper labial segment is proclined and spaced, particularly when the lower lip rests behind it, a URA with a labial bow works for this.

Question 10

How can functional appliances be used to corrrect an overjet?

Answer 10

Most effective during the pubertal growth spurt. If successful, results in overjet correctiuon with reduced anchorage demand later on as there is no longer an overjet to reduce.

Question 11

How can fixed appliances be used to reduce an overjet?

Answer 11

Space needs to be created first either by extractions or distalisation of buccal segments.
Once space created, labial segment can be retracted to reduce overjet.