Orthodontics

Question 1

Definition of Malocclusion

Answer 1

Variation from ideal occlusion which has dental health &/or psychosocial implications for the individual

Question 2

Benefits of Orthodontic Treatment

Answer 2

1. Dental health:
   - Caries
   - Periodontal disease
   - Trauma
   - Masticatory function (AOB)
   - Speech
   - Unerupted/ectopic teeth
2. Psychosocial well-being:
   - Social handicap
   - Negative judgement by others
3. Increased self esteem

Question 3

What is the prevalence of trauma for pts with an OJ of 0-3mm and > 6mm

Answer 3

0-3mm OJ = 14%

>6mm = 39%

Question 4

What is the percentage of numbers of teeth involved in trauma with increased OJ (0-3mm vs. >6mm)

Answer 4

19% 2(+) teeth with OJ 0-3mm

47% 2(+) teeth with OJ >6mm

Question 5

What percentage of cases with ectopic maxillary canines demonstrate root resorption

Answer 5

12.5%

3x more common in girls than boys.

Question 6

Risks/Problems with Ortho Tx

Answer 6

1. Cost/inconvenience
2. Pain & discomfort
3. Incomplete Tx
4. Medical disorders (bleeding disorders, epilepsy, allergies).
5. (TMD probs)
6. OH/Gingival/Perio health
7. Demineralisation/Caries
8. Root resorption
9. Relapse

Question 7

What is the mean root resorption for all maxillary incisors?

Answer 7

0.9mm

Question 8

What is the mean root resorption for most severely resorbed maxillary incisor?

Answer 8

1.5mm

Question 9

Pt factors that may affect root resorption

Answer 9

Genetic
Systemic disease
Nutrition
Age
Gender
Habits

Question 10

Dental factors that may affect root resorption

Answer 10

Short roots (Crown:root ratio)
Blunt/pipette shaped roots
History of trauma
Ectopic canines
Increased OJ
Endodontically treated
Alveolar bone density

Question 11

Treatment factors that may affect root resorption

Answer 11

Length of Tx
Fixed appliances
Rectangular archwires
Class II elastics
Continuous forces
Type of tooth movement
Degree of force
Jiggling forces

Question 12

What are the two components of the IOTN?

Answer 12

1. Dental Health Component

2. Aesthetic Component

Question 13

Classification of Malocclusion; Incisors (British Standard Classification)

Answer 13

Assess the position of the lower incisor tip in relation to where it occludes with the upper incisor cingulum plateau.
Class I = lower incisor tip occludes WITH or BELOW cingulum plateau of upper incisor.
Class II Div I = lower incisor tip occludes behind the cingulum plateau of the upper incisor. The upper central incisors are of average inclination or proclined.
Class II Div II = lower incisor tip occludes behind the cingulum plateau of the upper incisor. The upper central incisors are retroclined.
Class III = lower incisor tip occludes in FRONT of cingulum plateau of the upper incisor.

Question 14

Classification of Malocclusion; Buccal segments/molar relationship

Answer 14

Molar relationship = occlusion of upper and lower first permanent molars
Class I = mesiobuccal cusp tip of upper 6 occludes in the mid-buccal groove of lower 6.
Class II = mesiobuccal cusp tip of upper 6 occludes anterior to midbuccal groove of lower 6.
1/2 unit Class II = mesiobuccal cusp tip of upper 6 occludes cusp-to-cusp with the mesiobuccal cusp tip of the lower 6.
Class III = mesiobuccal cusp tip of upper 6 occludes posterior to mid-buccal groove of the lower 6.
1/2 unit Class III = mesiobuccal cusp tip of upper 6 occludes cusp-to-cusp with the distobuccal cusp tip of the lower 6.