Interceptive Orthodontics

Question 1

What is the most common neo-natal tooth? How treat?

Answer 1

Lower incisors

Extract if risk of inhalation or is causing difficulty with breastfeeding

Question 2

What are the three eruptive phases?

Answer 2

Pre-eruptive

Eruptive

Post-eruptive

Question 3

What occurs in pre-eruptive phase?

Answer 3

Starts when crown starts to form, ends when crown formation is complete

Small mesial and distal movements occur and the crowns reposition themselves within the growing and developing jaw

Question 4

What is the eruptive phase?

Answer 4

Starts when root begins to form, ends when teeth reach occlusal plane

Intra osseous stage is within bone, extra osseous is out of bone

Tooth germ moves into place as predecessor erupts / falls out

Question 5

What is the post eruptive phase?

Answer 5

Tooth movement and eruption continues as root forms throughout life

This can be due t abrasion or attrition, mesial drifts tends to occur when tooth surface loss occurs

Question 6

What’s occurs in the intra-osseous stage of eruption?

Answer 6

Root formation begins as proliferation of the epithelial root sheath begins and then dentine and pulp form

Tooth moves slowly incisally

Reduced enamel epithelium fuses with oral epithelium to form junctional epithelium

Question 7

What’s occurs in the extra-osseous stage of eruption?

Answer 7

Crown penetrates through epithelial layers

Epithelium becomes lower on clinical crown until gingiva is formed

Continues eruption until contacts tooth on opposing arch

Question 8

What causes eruption?

Answer 8

The dental follicle

• resorbs overlying bone
• facilitates connective tissue degradation and produces eruption pathway
• promote alveolar bone growth at base of tooth
• traction forces within the PDL via fibroblasts
• ectomesenchymal cells form root and cementum below

Question 9

What is interceptive orthodontics

Answer 9

Any procedure that will reduce or eliminate the severity of developing malocclusion

Question 10

Review eruption dates of permanent teeth

Answer 10

Question 11

The permanent dentition erupts lingual to the primary dentition… where is the space gained for this to occur?

Answer 11

Lateral growth of the jaw increasing inter canine width

Upper incisors erupting more proclined rather than straight like primary teeth

Question 12

Why might someone present like this?

Answer 12

Permanent canine germ is pressing on the root of the primary laterals

This tends to resolve itself later in development

<2.5mm diastema should close

Question 13

What concerns present themselves in these cases?

Answer 13

Left

• central incisors not erupted, yet laterals have
• cause for concern

Right

• asymmetry, lateral and contralateral central erupted but one central not
• should erupt within 6 months but if not then there is an issue

Question 14

Why might an upper central incisor not erupt?

Answer 14

Supernumerary teeth

Trauma to primary dentition can cause dilaceration of permanent tooth germ

Question 15

How would you investigate a missing upper central?

Answer 15

Proper history including trauma

Extra and intra oral assessment including palpating labially and palatally

Is primary tooth still there? Is it discoloured?

Radiograph with anterior occlusal or periapical

Question 16

How might one treat an unerupted central?

Answer 16

Extract supernumeraries

Maintain or make space for eruption

Monitor for 12 months if patient is <9 yrs old as they have immature root apex

If >9yrs old then expose tooth and use gold chain to apply orthodontic traction

Question 17

What can early loss of deciduous teeth cause?

Answer 17

Crowding

Centreline shift

Question 18

What is a balancing extraction? What is a compensating extraction?

Answer 18

Balancing

• removal of tooth opposite side of same arch to maintain position of centreline

Compensating

• removal of tooth from opposing quadrant to maintain occlusion and prevent over eruption

Question 19

Which teeth might you balance?

Answer 19

Cs

Es you tend not to balance but consider space maintainer to prevent shift

D’s can balance under GA

Question 20

What is a space maintainer?

Answer 20

Removable or fixed appliance used to maintain space of a lost tooth

Question 21

What impacts the decision on whether top extract poor prognosis first molars?

Answer 21

Age of patient / stage of development

Degree of crowding

Malocclusion type

Question 22

What are the general rules for extracting a 6

Answer 22

If extracting lower, compensate with the upper

Don’t balance the extraction if tooth is sound condition, well aligned or well spaced

If extracting upper, don’t extract lower

Question 23

How does digit sucking cause displacement on biting / posterior UNILATERAL crossbite

Answer 23

Narrowing of maxilla resulting in biting cusp to cusp

Because biting cusp to cusp, mandible must, displace to achieve ICP

Question 24

What is the ugly duckling stage?

Answer 24

11-12 years of age

Less than 2mm diastema between upper centrals

Mesial eruption of maxillary canines should close this space

Question 25

What is the leeway space?

Answer 25

Upper arch
- (primary canine + fm + SM) - (permanent canine + first premolar + second premolar) - 1-1.5mm

Lower arch
- (primary canine + fm + sm) - (permanent canine + first pm + second pm) = 2-2.5mm

Question 26

What % of children 6 and 12 have diastema

What diastema should close?

Answer 26

6 - 96%

12 - 7% - with 3s erupted

<2.5mm should close

Question 27

How manage ectopic eruption of the first permanent molar?

Answer 27

1. If pt <7 years, monitor 6 months - 90% self correct
2. Orthodontic separator
3. Attempt to distal use FPM
4. Extract the E
5. Distal disking of the E

Question 28

When should i assess first molars???

Answer 28

8-9 years of age!

any doubts re long term prognosis?
- refer for advice

Question 29

What space maintainers can i use?

Answer 29

Removeable
- passive URA
- clasps on 6’s, Southend clasp, baseplate extended around teeth to prevent unwanted mesial drift, with mesial stop on individual teeth if required

Fixed
- band and loop

Question 30

Most ideal result gained when FPM extracted when?

Answer 30

7 bifurcation calcifying

8s present

Class 1 / reduced overbite

Moderate lower crowding

Mild / moderate upper crowding

Question 31

How can interceptive tx be used on posterior unilateral crossbites?

Answer 31

Displacement on closure and IOTN?? - YES treat!

• URA hyrax screw, or coffin spring
• baseplate with posterior bite plane to disclude teeth

Question 32

How manage anterior crossbites???

Answer 32

Displacement, gingival recession, toothwear, mobility

• posterior bite plane
• Z spring
• Adam’s clasps

Question 33

When should habits be stopped before?

Answer 33

9!

Question 34

What instructions give to someone wearing an appliance?

Answer 34

Wear full time

Clean it twice per day minimum and after eating

Use fluoride mouthwash daily with no alcohol

Avoid sugar, sticky and hard foods

Remove for sports

Speech affected at first ad extra salvia but it will pass

Teeth moving and when eating might be painful