Orthodontic Problem Solving

Question 0

What reasons would indicate a requirement of more space in the lower arch?

Answer 0

1) relief of crowding
2) levelling an increased ciurve of spee
3) Correcting a centreline discrepency
4) uprighting distally angulated canines

Question 1

What are four ways in which the orthodontist can create space within the arch?

Answer 1

1) Extraction of teeth
- extraction of teeth closest to crowding produces more space
- mild crowding (1-4mm): non-extraction or second premolars
- moderate (5-8mm): first or second premolars
- severe (9+): first premolars
2) Transverse expansion of dental arch
- relapse dfue to movement oout of the neutral zone.
- space created within the arch is about half the amount of expansion (O’Higgins and Lee, 2000)
3) Anteroposterior lengthening of the arch
- via distal movement of buccal segments (via extraoral traction e.g. headgear)
- proclination of incisors - ffixed appliances. Retention necessary.
4) reduction in tooth width

Question 2

How should a retained deciduous tooth be managed?

Answer 2

Check radiographically and clinically for permanent succesor.
If arch space is at premium, maintainance may be required following tthe removal of the tooth, or space may need to be created.
1) If space is availible, the extttractino of the deciduous tooth nomrally leads to normal erruption of permanent successor
2) If space not availible, exposiure of permanent tooth +/- orthodontic traction may be required.
3) Extraction of the permanent succesor can be considered if position is unfavourable

Question 3

The second deciduous molar can often be retained due to an absence of the second premolar. How should this be managed?

Answer 3

1) Extraction to facilitate space closure
2) Extraction and prosthetic replacement
3) Retention of the second deciduous molar.

Question 4

One of the consequences of ankylosis is the ‘submergence’ or infracocclusion of the affected teeth relative to the occlusal plane. How should this be managed?

Answer 4

1) In the presence of a permanent successor and minimal infraocclusion, the ankylosed tooth can be left under exfoliation to exfoliate naturally
2) If infraocclusion becomes greater, consideration should be given to either restoring the vertical dimension or extracting the affected tooth

Question 5

How should congenital tooth abssence be managed?

Answer 5

1) Space closure

2) Maintainene orr opening of space followed by prosthetic replacement of missing teeth

Question 6

What are some local factors that cause a disturbance in tooth eruption?

Answer 6

1) Crowding
2) Trauma
3) Ectopic position of the tooth germ
4) Supernumery teeth
5) Retained deciduous teeth
6) Ealy extraction of deciduous teeth
7) Transposition
8) Local pathology

Question 7

How should an unerupted permanent maxillary central incisor bee managed?

Answer 7

1) In the absence of a cenral incisor, the laterals tend to drift towards the midline losing arch space. Space can be recreated usingg removable or fixed appliances and the extraction of c’s
2) If associated with supernumery tooth, extract supernumery andd wait 12 months. If fails to erupt, can expose and bond a bracket.

Question 8

At the age of 10 years, the maxiallary canine bulge should be palpable in the buccal sulcus adfjacent to the lateral incisor root. What clinical features might suggest an impacted canine?

Answer 8

1) Lack of buccal bulge
2) Palatal bulgge
3) Delayed eruption, marked distal angulattion, absence of lateral incisor
4) Firm deciduous canine indicating a lack of resorption (particularly past 14 years)

Question 9

An impacted canine can be associated with risk of damage to adjacent teeth, particularly the lateral and occasionally the centtrals. How should they be managed?

Answer 9

1) Surgical exposure followed by orthodontic alignment
2) Autotransplantation of the tooth (if orthodontic alignment is not practical)
3) EXtraction
4) Leave in situ (rarely ever)

Question 10

Impaction of the upper 6 agaisnt the E occurs in about 4% of the population and is inddicative of posterior crowding. How should this be managed?

Answer 10

1) Leave to spontaneously erupt and intervention if nothing hapens within 6-12 months
2) Seperating elastic, sprring or brass wire placed bellow the contact point between permanent and deciduous molars
3) Distal grinding of the E
4) Extraction of the E (but leads to space loss and mesiial tipping of thee 6 which will require further orthoddontic correction)

Question 11

A maxillary midline diastema can be a normal feature and dental development an will often improve following the eruption of the permanent canines. What other causes of this exists?

Answer 11

1) Spacing of the dentition
2) Proclination of upper incisors
3) Congenital absence of lateral incisors
4) Midline supernumery
5) Pathology in anterior maxilla
6) Prominent labial frenum

Question 12

Management of midline diastemas will depend primarily upon the underlying cause. Once determined, how should a midline diastema be managed?

Answer 12

In the absence of any obstructions or pathologies, active orthodontic treatment is usually carried out in the permanent dentition and unless small, bodily movement of the incisors using fixed appliances will be required. Long term retention is necessary usually. If a diastema is small, can convince the patient that it is a unique feature of individuality.
If a prominent labial frenum is suspected, frrenectomy can be prescribed after orthodontic closure of the diastema which should be carried out in the permanent dentition after the eruption of the maxillary canines

Question 13

A prolonged digit sucking can give rise to a number of chharacteristic features as part of a malocclusion often manifesting in the late deciduous or early mixed dentitions. What are some of these characteristics?

Answer 13

1) Proclination of the upper incisors
2) Anterior open bite (often with a degree of assymetry)
3) Narrow maxillary arch
4) Posterior crossbite
5) Increased lower facial height

Question 14

How does prolonged digit sucking affect the oral tissues?

Answer 14

Reduced tongue position and negative intraoral pressure.

Question 15

Teeth can erupt into a position of crossbite during the mixed dentition, either individually or within a group. Early correction is indicated particularly if the crossbite is associated with mandibuliar displacement or periodontal damage. How can this be achieved?

Answer 15

1) Posterior crossbite:
In the mixed dentition could be due to a skeletal discrepency, persistant digit sucking habit.
A removable appliance with a midline expansion screw can be used.
If some skeletal change is required, can use fixed palatal expanders such as a quad or trihelix
2) Anterior crossbite:
If space is availible, a removable appliance can be used to push the upper incisor teeth over the bite using palatal springs. A posterior bite plane can be used to eliminate occlusal interferences for this.
If space or bodily movements are required, fixed appliances a 2 x 4 appliance can be used (four brackets on the upper incisors and bands on first molars). The bite can be opened with GIC on the occlusal surfaces of first molars.