Jane's Wiggs Chapter 19 - occlusion and orthodontics

Question 1

According to Wiggs Chapter 19 - Occlusion and Orthodontics,

What is referred to by scissors bite?

Answer 1

normal relationship of the maxillary incisors overlapping the mandibular incisors whose incisal edges rest on or near the cingulum on the lingual surfaces of the maxillary incisors

Question 2

According to Wiggs Chapter 19 - Occlusion and Orthodontics,

Describe the difference between overbite and overjet?

Answer 2

overbite is the vertical component and overjet is the horizontal component of abnormal overlapping incisors

Question 3

According to Wiggs Chapter 19 - Occlusion and Orthodontics,

What does embracation mean?

Answer 3

Irregular arranged teeth within an arch due to a lack of space (crowding), typically seen in mandibular incisors and maxillary premolars in brachycephalic breeds.

Rotated, tipped, supraerupted (supraclusion), infraerupted (infraclusion), and displaced teeth are not uncommon in embrication.

Question 4

According to Wiggs Chapter 19 - Occlusion and Orthodontics,

What is the difference between version and displacement?

Answer 4

version is the tipping of a tooth crown, displacement is bodily movement in one direction or another

Question 5

According to Wiggs Chapter 19 - Occlusion and Orthodontics,

what are consequences of untreated deciduous malocclusions when an interlock is present?

Answer 5

prevent normal growth of the mandible or maxilla depeding on the interlock

Question 6

According to Wiggs Chapter 19 - Occlusion and Orthodontics,

What are the categories of orthodontic treatment?

Answer 6

interceptive, preventative and corrective

Question 7

According to Wiggs Chapter 19 - Occlusion and Orthodontics,

what are interceptive orthodontics?

Answer 7

extraction or recontouring (crown reduction) of primary or permanent teeth that are contributing or will contribute to alignment problems of the permanent dentition

Question 8

According to Wiggs Chapter 19 - Occlusion and Orthodontics,

At what age is it recommended to extract canine teeth causing an interlock?

Answer 8

4-8 weeks (no later than 12) to maximize period of normal growth

Question 9

According to Wiggs Chapter 19 - Occlusion and Orthodontics,

What are preventive orthodontics?

Answer 9

Preventive orthodontics is the evaluation and elimination of conditions that may lead to irregularities in the developing or mature occlusal complex

**Usually does not actually include doind anything**

monitoring eruption, addressing conginital issues, genetic counseling, behavioural treatment etc.

Question 10

According to Wiggs Chapter 19 - Occlusion and Orthodontics,

What are corrective orthodontics? What are the two stages?

Answer 10

corrective orthodontics is performing orthodontic treatment for an existing problem. divided into the treatmetn phase and the retainer phase

Question 11

According to Wiggs Chapter 19 - Occlusion and Orthodontics,

What happens when light and heavy forces are applied in orthodontic tooth movement?

Answer 11

When a light to mild force is applied, it acts as a stimulus to initiate cellular activity resorption and deposition of bone, which is termed the physiologic movement.

When these pressures are exceeded with a heavy force there will be necrosis of periodontal tissues on the pressure side and poor to no deposition of bone on the traction side, which is labeled pathologic movement.

Question 12

According to Wiggs Chapter 19 - Occlusion and Orthodontics,

What is the classical theory of tooth movement?

Answer 12

Pressure tension theory

Question 13

According to Wiggs Chapter 19 - Occlusion and Orthodontics,

briefly describe the pressure tension theory

Answer 13

On the pressure side (direction of tooth movement), the PDL is compressed with an increase in the capillary pressure and blood supply at pressure points, initially the alveolar crest. Stimulates bone remodelling and recruits cells responsible

on tension side, PDL is stretched, resulting in a widening of the periodontal membrane space. In response the capillary blood flow and cellular activity increases. This results in the deposition of new bone along the traction areas of the lamina dura

Question 14

According to Wiggs Chapter 19 - Occlusion and Orthodontics,

What are the phases of orhtodontic tooth movement, how long does each last and what is the main event occurring in each?

Answer 14

phase 1 - initial movment, lasts 24-48 hours; rapid initial movement followed by slower creep

Phase 2 - lag phase lasts 20-30 days. Macrophages remodel the necrotic and hyalinized PDL

Phase 3 and 4 - post-lag phase - phase where real tooth movement occurs by osseous remodelling

Question 15

According to Wiggs Chapter 19 - Occlusion and Orthodontics,

What are the 6 basic types of tooth movement?

Answer 15

tipping,

radicular (root),

translation (bodily),

rotation (torsion),

extrusion,

intrusion

Question 16

According to Wiggs Chapter 19 - Occlusion and Orthodontics,

What is the most common orthodontic movement in vet med?

Answer 16

tipping

Question 17

According to Wiggs Chapter 19 - Occlusion and Orthodontics,

Rank the following orthodontic movements from hardest to easiest to accomplish?

Radicular, Torsion, Intrusion, Extrusion, Tipping, Translation

Answer 17

Intrusion, rotation, translation, radicular, tipping, extrusion

Question 18

According to Wiggs Chapter 19 - Occlusion and Orthodontics,

What is the recommended minimum advantage ratio of anchorage to movement target?

Answer 18

2:1 -

(Wiggs says it is often incorrectly stated as the root surfacec area - however doesn’t elaborate on what IS correct.)

Question 19

According to Wiggs Chapter 19 - Occlusion and Orthodontics,

What are the two types of force application?

Answer 19

Passive/intermittent force

Continuous force

Question 20

According to Wiggs Chapter 19 - Occlusion and Orthodontics,

How much force should be applied for orthodontic movement?

Answer 20

20–26 g/cm2 of tooth root surface.

Question 21

According to Wiggs Chapter 19 - Occlusion and Orthodontics,

What are two general types of orthodontic devices?

Answer 21

Removeable or fixed

Question 22

According to Wiggs Chapter 19 - Occlusion and Orthodontics,

When considering bends in orthodontic wires, what are first, second and third order bends?

Answer 22

First-order bends are in the horizontal plane, and are in and out bends.

Second-order bends are in the vertical plane, and are up and down bends.

Third-order bends are bends that produce a torque force

Question 23

According to Wiggs Chapter 19 - Occlusion and Orthodontics,

How long of a retainer period is recommended?

Answer 23

simple movement - two to six weeks is required.

In more complex movements and those involving the torsiversion, 4–12 weeks is recommended.

Question 24

According to Wiggs Chapter 19 - Occlusion and Orthodontics,

in orthodontic tooth movement, what usually happens to alveolar crestal bone?

Answer 24

it is resorbed and remodels, but usually keeps the same relationship to the tooth - ie. seems to ‘travel’ with the tooth and alveolar crest will be at the same height relative to the tooth after movement.

Question 25

According to Wiggs Chapter 19 - Occlusion and Orthodontics,

what are direct and indirect appliances?

Answer 25

direct is applied chairside, indirect is made by a dental lab.