Introduction to orthodontics

Question 1

What is malocclusion?

Answer 1

Variation in occlusion which has dental and/or psychosocial implications
Malocclusion is a variation not a disease

Question 2

What is dentofacial orthopaedics?

Answer 2

Modify growth to improve relationships between facial bones

Question 3

What are the 3 types of appliances?

Answer 3

Fixed
Functional
Removable

Question 4

How does a removable appliance work?

Answer 4

Tipping movements - applied a single-point contact force to the crown of the tooth, the tooth tilts around the fulcrum
Movement of blocks of teeth because connected by baseplate
Influencing the eruption of opposing teeth

Question 5

How does a functional appliance work?

Answer 5

Utilise, eliminate or guide forces of muscle function, tooth eruption and growth to correct a malocclusion
Work by the principle of posturing the mandible forwards in growing patients

Question 6

What are functional appliances use for?

Answer 6

Most effective in correcting the anterioposterior occlusion between the upper and lower arches usually in patients with moderate-mild class II skeletal 
Reduced overjet

Question 7

What are the dental health benefits of orthodontic treatment?

Answer 7

Caries
Periodontal disease
Trauma
Masticatory function
Speech
Unerupted/ectopic

Question 8

What are the psychosocial benefits of orthodontic treatment?

Answer 8

removes the social handicap
Positive judgements by others
Increased self-esteem

Question 9

what appliance can be used when patient has a posterior crossbite?

Answer 9

Quad helix on first permanent molars expands arches

Question 10

Why do people with an increased overjet have poor perio?

Answer 10

Incompetent lips - gingiva exposed to air, inflamed gingiva
People with increased overjet dont like their teeth so dont look after them well
But, people who have had ortho treatment dont have better health

Question 11

What is the incidence of increased trauma if have an increased overjet?

Answer 11

14% with OJ 0-3mm

39% with OJ >6mm increased overjet

Question 12

What is the other treatment option to correct OJ?

Answer 12

Functional/headgear - 2-phase treatment: once when patient is 8-10 and again in adolesence when have all teeth
One phase treatment: in adolescense more economical to restore the trauma

Question 13

How can fixing malocclusion affect speech?

Answer 13

There is no proof that alteration of tooth position can improve articulation disorders
Difficult to learn how to talk

Question 14

What is the problem with unerupted/ectopic teeth?

Answer 14

Resorption of surrounding roots

Cystic change

Question 15

What are the psychosocial well being benefits of treatment?

Answer 15

Social handicap - positive vs negative social judgement
Negative judements of others - teasing and bullying, but psychological distress is not proportional to the severeity of malocclusion

Question 16

What are the reasons for orthdontic treatment?

Answer 16

Health is a state of complete physical, mental and social well-being not just the absence of disease - aiming to improve their health and social well-being

Question 17

What are the risks/problems with orthodontic treatment

Answer 17

Cost/inconvenience 
Pain and discomfort 
incomplete treatment - if not looking after teeth will ust stop treatment
Medical disorders - bleeding, epilepsy
Oral hygiene/gingival/perio health
Demineralisation/caries 
Root resorption 
Relapse

Question 18

What is the mean resorption fot maxillary incisors?

Answer 18

0.9mm

17% had root shortenings >2.5mm for one or more maxillary incisors

Question 19

What are the patient factors for root resorption?

Answer 19

Genetic
Systemic disease 
nutrition
Age 
Gender 
habits

Question 20

What are the dental factors for root resorption

Answer 20

Short roots 
Blunt/pipette shaped
History of trauma
Ectopic canines 
Increased overjet
Endo treated
Alveolar bone density

Question 21

What are the Treatment factors for root resorption?

Answer 21

Length of treatment 
Fixed appliance 
Rectangular arch wires class II elastics 
Continuous forces
Type of movement 
Degree of force
Jiggling forces

Question 22

What are the 2 components of the IOTN?

Answer 22

Dental health component and aesthetics

Question 23

What is the incisor relationship?

Answer 23

Assess the position of the lower incisor tip in relation to where it occludes with the upper incisor cingulum plateau

Question 24

What is a class I incisor relationship?

Answer 24

Lower incisor tip occludes with or below the cingulum plateau of the upper incisor

Question 25

What is a class II div I incisor relationship?

Answer 25

Lower incisor tip occludes behind the cingulum plateau of the upper central incisors are of average inclination or proclined

Question 26

What is a class II div II incisor relationship?

Answer 26

Lower incisor tip occludes behind the cingulum plateau behind the upper incisor
Upper central incisors are retroclined

Question 27

What is a class III incisor relationship?

Answer 27

Lower incisor tip occludes in front of the cingulum plateau of the upper incisor

Question 28

What is a class I buccal relationship?

Answer 28

Mesio-buccal cusp tip of upper 6 occludes in the mid-buccal groove of the lower 6

Question 29

What is a class II buccal relationship?

Answer 29

Mesio-buccal cusp tip of upper 6 occludes anterior to the mid-buccal groove of the lower 6

Question 30

What is a 1/2 unit class II buccal relationship?

Answer 30

Mesio-buccal cusp tip of upper 6 occludes cusp-to-cusp with the mesio-buccal cusp tip of the lower 6

Question 31

What is a class III buccal relationship?

Answer 31

Mesio-buccal cusp tip of upper 6 occludes posterior to the mid-buccal groove of the lower 6

Question 32

What is a 1/2 unit class III buccal relationship?

Answer 32

Mesio-buccal cusp tip of upper 6 occludes cusp-to-cusp with the disto-buccal cusp tip of the lower 6