Orthodontics - Interceptive Orthodontics Flashcards

1
Q

what is interceptive orthodontics?

A

Any procedure that reduces/eliminated the severity of developing malocclusion.

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2
Q

what will be the percentage of crowding in the permanent dentition if the primary dentition has no spacing?

A

66%

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3
Q

what will be the percentage of crowding in the permanent dentition if the primary dentition has <3mm spacing?

A

50%

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4
Q

what will be the percentage of crowding in the permanent dentition if the primary dentition has 3-6mm spacing?

A

20%

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5
Q

what will be the percentage of crowding in the permanent dentition if the primary dentition has >6mm spacing?

A

none

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6
Q

does 3.5mm of lower labial segment crowding require intervention?

A

no, crowding can spontaneously improve due to transverse growth across the inter-canine width.

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7
Q

what causes kicked out later incisor crowns? - explain

A

Ectopic canine

The unerupted permanent canine is leaning against the roots of the laterals, this will correct once the canines erupt

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8
Q

where does the upper buccal segment span from?

A

Distal of lateral incisor and mesial aspect of the FPM

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9
Q

Why at 6 y/o do 96% of patients have a diastema compared to 7% at 12 y/o?

A

The permanent canine erupts around this age and is much larger than the deciduous so takes up more space and rearranges the teeth.

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10
Q

what size of diastema is likely to close?

A

< 2.5mm

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11
Q

what causes a median diastema? (3)

A
  • Smaller teeth
  • 10% associated with Supernumerary tooth which is not interfering with eruption of adult teeth i.e. conical SN
  • Missing teeth
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12
Q

after eruption, how long after should contralateral teeth erupt?

A

6 months after

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13
Q

what can cause upper centrals to not erupt?

A
  • Supernumerary teeth
  • Trauma = dilaceration or other pathology of the permanent successor
  • Pathology
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14
Q

how do we treat supernumerary teeth?

A
  1. Remove the supernumerary and retained deciduous teeth
  2. Expose the permanent tooth (conflicting opinion over use of bonding)
  3. Create space
  4. monitor for > 1.5 years
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15
Q

how long should you monitor eruption after the removal of a supernumerary tooth?

A

1.5 years

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16
Q

define lee way space.

A

Marked difference in size between deciduous and permanent successors – especially canine and premolars

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17
Q

how much wider is the permanent 3,4,5 in the maxillary arch than the baby teeth?

A

1.5mm

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18
Q

how much wider is the permanent 3,4,5 in the mandibular arch than the baby teeth?

A

2.5mm

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19
Q

at what age should you take a space requirement measurement?

A

aged 9

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20
Q

where do you measure from in a space requirement measurement?

A

Measure from the mesial of the 6 to the distal of the 2 (same as buccal segment)

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21
Q

what is the ideal amount of lee way space?

A

18.5mm

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22
Q

what teeth should you balance after premature loss? (2)

A

C’s = balance

possibly D’s if under GA already

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23
Q

what causes midline shift?

A

premature removal of a C without balancing.

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24
Q

how can midline shift be corrected?

A

shifts can only be corrected in the permanent dentition by fixed appliances

25
Q

what are the rules when extracting grossly carious unrestorable 6’s? (5)

A

If extracting the lower compensate by removing the upper

Treat each side separately don’t balance with a sound tooth

Remove 6’s ideally when the 7’s furcation is formed
& when the 8’s are forming
& when the premolars have erupted - 5 uses the first permanent molar to erupt into the correct position

26
Q

how long does it take to correct an posterior crossbite?

A

6-9 months

27
Q

how long does it take to correct an anterior crossbite?

A

6-8 weeks

28
Q

why do we overcorrect posterior crossbites?

A

to compensate for the 50% chance of relapse

29
Q

how do we prevent relapse of posterior crossbites?

A

Once the CB is corrected wear the appliance for a further 3 months without being activated to prevent relapse

30
Q

what habit is more preferable, dummy or digit?

A

Dummy better then digit sucking but none have good outcomes

31
Q

what are the dental outcomes of sucking habits? (4)

A

Proclined upper incisors

Retroclined lower incisors

localised AOB or incomplete OB

Unilateral posterior crossbite and narrow upper arch

32
Q

what can be used to prevent digit sucking habits? (5)

A

URA Removable habit breaker – goal post

Fixed habit breakers – cemented

Behavioural management therapy i.e. positive reinforcement

bad tasting polish

dummy instead

33
Q

up until what age can you remove the habit and the teeth will erupt back into the normal position within 12 months to 3 years?

A

10 years old

34
Q

how do we manage retained deciduous teeth in the late mixed dentition?

A

investigate to see if the permanent tooth is present and remove the retained primary tooth

35
Q

what is a submerging deciduous tooth?

A

where the tooth becomes ankylosed to the bone

36
Q

how do we manage a submerging deciduous tooth?

A

If there is a permanent successor = will undergo normal exfoliation so observe for 1 year.

If there is no permanent successor = extract

37
Q

when do we extract a submerging deciduous tooth?

A

No permanent successor and When there is 1mm of crown above the gingiva (just before it becomes subgingival)

38
Q

where do permanent canines develop?

A

Develop palatally – just below the orbit

39
Q

where do permanent canines sit in the gum?

A
  • Labially

- Distal to the root apex of laterals

40
Q

when do you start to assess a patient for canines within the gum?

A

palpate the gum and alveolus from the age of 10

90% are palpable by the age of 11

41
Q

what do we look for when assessing if a patient canine is about to erupt? (4)

A
  • Bulges
  • Mobile c’s
  • Tipped lateral incisors
  • Asymmetry
42
Q

if you cannot palpate a canine at age 11 what are the next steps?

A

radiograph OPT or Maxillary anterior occlusal

43
Q

what radiographs do you take to assess an ectopic canine?

A

OPT

Anterior maxillary occlusal

44
Q

what do you do if you identify an ectopic canine? (1)

A

If < 13y/o Extract the C’s

can be done up until the age of 13 – after this the dentition is established and ortho intervention is required

45
Q

what impact do ectopic canines have on the surrounding dentition?

A

34% of lateral incisors have resorption

15% of centrals have resorption

46
Q

what positioning factors determine the outcome of ectopic canine eruption? (3)

A
  • How high up the canine is placed
  • How much of the adjacent incisor is over lapped/how close to midline
  • angulation of the tooth >30 degrees or horizontal = poor prognosis
47
Q

what is the percentage chance of self-alignment of permanent canines If overlap is less than ½?

A

90% chance of self-alignment

48
Q

what is the percentage chance of self-alignment of permanent canines If overlap is more than ½?

A

60% chance of self alignment

49
Q

what causes overjets? (3)

A

small lower jaw

big upper jaw
(combination of both)

obtuse cranial base

50
Q

how do we know if a patient with an overjet can be treated with a URA?

A

If they can achieve an edge to edge bite

51
Q

what incisor angulation (both upper and lower) allow tipping of the teeth?

A

upper incisor angulation is < 120

and lower angulation is > 80

52
Q

what appliances can we use in interceptive treatment of CLASS 3 ? (6)

A
  1. Functional regulator (FR)
  2. Frankel (FR) III – tries to change the sift tissue enviro to allow the teeth to move in the desired direction
  3. Rapid maxillary expansion
  4. Reverse pull head gear (can be used together = 70% success)
  5. Strong class III elastics fixed by bone screws and plates = 90% success
  6. Can also carry out camouflage treatment with a URA
53
Q

what are the limitations of the Frankel (FR) III? (3)

A
  • expensive
  • bulky and hard to wear
  • < 30% success
54
Q

define camouflage treatment

A

Changing the incisor relationship (to class 1) whilst maintaining the natural skeletal relationship

55
Q

what appliances can we use in interceptive treatment of CLASS 2 ?

A
  1. Functional appliances
    - Twin block = 80% compliance

Single block appliances = 30% compliance

  • Median opening activator
  • FR II
  • Bionator
  1. Headgear to restrict maxillary forward growth
56
Q

what problem can occur if deciduous teeth are removed before the permanent successor is is ½ to 2/3rds developed?

A

delayed eruption

57
Q

what are the advantages of removing the permanent 6’s at the correct time? (3)

A

7’s will erupt to close the space

the child will enter the adult dentition free of caries

helps to prevents crowding

58
Q

what are the disadvantages of removing the permanent 6’s? (2)

A

Demanding in terms of cooperation for the child

May need to use GA which carries lots of risks