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Flashcards in Ortho Deck (77):
1

What is perfect occlusion?

Class 1 molar and incisor relationship, no crowding or spacing, perfect crown angulation/inclination, no rotations, flat occlusal plane

2

What is normal occlusion?

The normal variation from perfect occlusion

3

What is malocclusion?

Teeth that dont fit together due to: dent-alveolar factors (crowding/spacing), skeletal pattern (class 1/2.1/2.2/3), soft tissues (lips, cheeks and tongue) and local factors (missing/ectopic/extra teeth)

4

What are the risks of crowded teeth?

caries perio

5

What is the risk of having an overjet?

Tooth damage from trauma

6

What is a functional appliance?

Corrects class II and jaw alignment, can be either fixed or removable, work by retraining U jaw and increasing growth of L jaw by 1-2 mm

7

What is a fixed appliance/

Attached to teeth and capable of causing bodily movement of teeth and rotation

8

What is a removable appliance?

A brace that can be removed from the mouth and tilts single teeth and widens the arches

9

What is balancing?

When you also extract any tooth on the opposite side fo at the same arch to keep the centre line

10

What is compensating?

When you also extract the same tooth in the opposite arch ti prevent over-eruption and maintain the molar relationship

11

How common are submerged teeth?

9%

12

Which jaw are submerged teeth more common?

Mandible

13

What is submergence?

Infraoccluded deciduous teeth when successor is absent (may also shed when successor erupts or occasionally prevents eruption of the successor)

14

Why is there variation in dentoalveolar factors?

Genetics (60%) and unknown environmental factors (40%)

15

How common is class 1?

94%

16

What order do the classifications go in frequency?

1 > 2.1 >2.2 >3

17

What causes crowding?

Large teeth, small arch, combo of both

Teeth are mesially angulated hence they erupt forward = crowding

18

How should deciduous teeth look?

Spaced (3 years) to make room for the permanent teeth and close all available teeth (8.5 years)

19

What is predictive of permanent teeth?

Deciduous teeth at 5 years are:
Crowded = 100%
<3mm spacing = 50%
>6mm spacing = 0%

20

What is the consequence of early loss of D's and E's?

Premolar crowding

21

What dictates where permanent teeth erupt?

pre-eruptive position
(if not enough space for 2s they will erupt palatally unless c's are removed)

22

How do we treat crowding?

Extracions
Lateral arch expansion
Antero posterior (headgear)

23

How do we treat spacing?

Closing space
Redistributing space (fill prosthetically)

24

What is are the different class ANB angles?

Class 1 2-4 degrees (3.4 most common)
Class 2 >4 degrees
Class 3 <2 degrees

25

What is the frankfort plane?

Infraorbital ridge to EAM

26

What are the signs of an increase lower face height?

Clinically lines meet anterior to back of head
Anterior open bite, reduced overbite and separation of lips

27

What are the signs of reduced lower face height?

Clinically lines meet posterior to back of head
Prominent chin, increased overbite, lips cover teeth

28

Define dento-alveolar compensation:

Where the lips and tongue guide erupting teeth into better positions than skeletal class would suggest

n.b. dental bases determine apex location but soft tissues determine crown position

29

What is the neutral zone?

Where soft tissue continuous forces don't act (oppose each other equally)

30

How do soft tissues effect stability of treatment?

If teeth are moved into an unstable position (e.g. arches expanded) soft tissues apply pressure making it more likely to relapse.

31

What is a class 1 incisor relationship?

Ideal overjet and overbite

32

What is lip competence?

Lips meet together at rest without any muscle activity

33

What is incompetent but held together?

Lips meet together when mentalis contracts

34

What is mild incompetence?

<1/2 crown showing

35

What is marked incompetence?

>1/2 crown showing (this is the only one that matters)

36

How does lip competence change with age?

Improves (elevates at 9-11 yrs reducing the overjet)

37

What does lower lip length determine?>

The lip line

38

What is a normal lower lip length?

at rest it overlaps 3-6mm/ 1/3 of U2 incisal crowns

39

If lip line unfavourable (low lip line or incompetent lips) what do you do?

1. accept
2. reduce overjet to <2mm and stabilise occlusion (keep braces on for longer

40

What does the upper lip length determine?

Amount of upper incisors visible - aesthetics only
Normal 2-3 mm,
'unattractive gummy smile' >2mm

41

What are the consequences of digit sucking?

Narrow upper arch
Cross bite

42

What are the consequences from the tongue?

Affects lower arch size
Tongue thrusts (adaptive to incompetent lips to produce anterior seal or endogenous like in downs syndrome or anterior open bite)

43

What data do you collect for orthodontic diagnosis?

Skeletal pattern - anterio-posterior, vertical, transverse
Soft tissue - lip competency, lip line, upper lip height, tongue, cheeks
Dentoalveolar factors - crowding (mild

44

What is a class 1 molar relationship?

The U6 mesiobuccal cusp sits in the buccal groove of the L6)

45

What should a treatment plan include?

1) Malocclusion diagnosis
2) Problem list (recording negative aims i.e. problems that you're going to 'accept'O
3) Plan treatment aims (improve OH, reduce overjet)
4) Plan treat,emt means - i.e. how wet re going to do it ( (OHI, XLA, FA)

46

Why do we need radiographs in ortho?

- presence of teeth (primary, secondary, missing, ectopic, cysts)
- Position (skeletal class and position of teeth)
- pathology (caries/ bone levels/apical pathology/root resorption/trauma/TMJ disease/cyst)
- pre treatment for diagnosis and treatment planning
- mid treatment for surgical planning, growth changes, treatment progress (indicates stability), root positions, pathology
- post treatment (rare) surgical/ortho relapse and resorption

47

What can a lat ceph show?

- assess U + L jaws and cranial base (SK class)
- tooth inclinations (occlusal class)
- find ectopic teeth
- implant planning
- monitor growth
- treatment plan and progress

48

When are lat cephs used?

Pt with:
SK discrepancies using functional/ fixed appliance
Orthognathic surgery
Unerupted teeth

49

What is a class 1 incisor relationship?

The tip of the lower incisor occludes or projects onto the cingulum plateaux of the upper central incisor

50

How common is a class 1 incisor relationship?

60%

51

What usually needs to be fixed in a class 1 relationship?

Local factors:
Crowding
Spacing
Bimaxillary proclination
Hyperdontia/hypodontia/macrodontia/microdonti/ectopic canines/transposition etc.
Anterior open bite
Posterior cross bite

52

What are the causes of an anterior open bite?

Skeletal pattern
Endogenous tongue thrusting
Digit sucking

53

What are the causes of a posterior cross bite>

Narrow maxilla
Digit sucking
Crowding
Mandibular displacement

54

What is class 2.1 incisor relationship?

The lower incisor tip contacts or projects behind the cingulum plateaux of the upper central incisors (overjet) and the upper centrals are proclaimed or normal

55

What are the contributing soft tissue factors of a class II incisor relationship?

Low lip line
Marked incompetence
Loose lips

56

How does the incisor classification affect trauma risk?>

In a class II relationship the upper incisors are more likely to be traumatised due to the overheat (5mm 22%. 9mm 24%, >9mm 44%)

57

What are fixed appliances good at?

Multiple bodily movement of upper labial segment
Rotations
Spacing
Crowding
Non aligned arches

58

What us 2.2 incisor relationship?

The lower incisor tip occludes or project posteriorly to the cingulum plateaux of the upper central incisors and the upper central incisors are retroclined

59

Which incisor class is growth favourable to?

Class 2 - jaw grows down and out

60

What is the average growth of a childs mandible?

2mm increase from 11 y/o to end of growth

61

What is class 3 incisor relationship?

The lower incisor tip occludes or projects anterior to the cingulum plateau of the upper central incisors

62

When are girls in their peak growth?

12 years

63

When do girls stop growing?

16 years

64

When are boys in their peak growth?

14 years

65

When do boys stop growing?

18 years

66

How do we monitor facial growth?

Monitor height using tanner graphs - parallel to facial growth - we cannot predicts changes in SK only assume average

67

When does inter canine width stop?

At 10 y/o

68

When should you treat class 2?

Early (growth is favourable)

69

when should you treat class 3?

Late (growth unfavourable)

70

When should orthognathics and implants be done?

Once growth has stopped

71

How does headgear and functional appliance affect growth?

Restrains Maxilla and enhances growth in mandible (2-3mm)

72

What is relapse?

The return of malocclusion following correction

73

What is stability?

teeth in equilibrium with soft tissues

74

What is retention?

Stabilisation of post treatment occlusion

75

What are the causes of relapse/factors of stability)

Occlusion - overbite in class 3 = 135 intercuspal angle in class 2.1, intercuspation in all cases
Soft tissues - incompetent lip, teeth out of neutral zone, lips
Growth - worsened lower ant. crowding, forward mandibular rotation = increased overbite, backward mandibular rotation = worsen anterior open bite
Periodontal tissues - new bone more susceptible to remodel (3 months), sharpey fibres reorganise (1-2 months), supracrestal fibres (reorganise >6 months), free gingival fibres (reorganise >12 months)

76

When do we use a fixed retainer?

When instability is more likely:
Rotations
Diastema
Lower incisor crowding
Periodontal disease
- arch expansion or incisor proclamation (L)

77

What are the disadvantages of fixed retainer?

Fall off - esp. upper arch
Hygiene = caries
- only retain front teeth