Orthodontic Level 4 - Unit B

Question 1

What is the biggest indication for orthodontic camouflage?

Answer 1

Class II malocclusion is the major indication for orthodontic camouflage.

Question 2

What extraction patterns are used for class II camouflage?

Answer 2

Maxillary first premolars

Maxillary first and mandibular second premolars

Maxillary and mandibular first premolars

Question 3

Why are any teeth extracted from the mandibular arch if the goal is to retract the lower incisors?

Answer 3

It would be important not to retract the lower incisors–if that happened the overjet could not be reduced. But it also is important not to move the lower incisors more than slightly forward, because then lip pressure would cause them to relapse backward, leading to both incisor crowding and return of excessive overjet.

Question 4

What is the most common reason for orthodontic camouflage?

Answer 4

Class 2 malocclusion

Question 5

How is space to retract teeth obtained for orthodontic camouflage?

Answer 5

3 possible extraction patterns:

Maxillary first premolars

Maxillary first and mandibular second premolars

Maxillary and mandibular first premolars

Question 6

Why are the mandibular arch teeth extracted if the goal is to retract the upper teeth?

Answer 6

It would be important not to retract the lower incisors but it is also important not to move the lower incisors forward because they would end up relapsing causing incisor crowding and excessive overjet.

Question 7

When is extraction of lower arch done for reducing overjet?

Answer 7

So extraction in the lower arch is done when Class II elastics will be used during the treatment to help reduce the overjet. These elastics, connected from the lower molars to the upper incisors, pull the upper incisors back and the lower molars forward.

Question 8

What is done differently with class II elastics?

Answer 8

Extraction in the lower arch if the second premolar.

Question 9

When can camouflage not adequately achieve effective treatment outcomes?

Answer 9

If the mandibular deficiency is severe enough camouflage can’t produce an acceptable result.

Question 10

How can patients be shown the outcome of the facial effects of different kinds of treatment?

Answer 10

Computer simulations which use computer algorithms that relate that amount of change in the facial soft tissues.

Question 11

Which is more often successful, repairing class 2 or class 3 via camouflage?

Answer 11

Class 2 problems. This is because skeletal problems are not repairable with retroclusion of the lower incisors.

Question 12

What does the fact class 3 camouflage is less often successful mean?

Answer 12

Higher percentage of class III than class II patient require surgery

Retracting lower incisors a long way is rarely indicated.

Question 13

What is the usual method of class III camouflage?

Answer 13

Extracting one of the lower incisors.

Question 14

What are the potential problems of using camouflage to treat malocclusion?

Answer 14

1) Worse, not better, facial esthetics. Retracting the incisors too much can make the skeletal problem more apparent, just the opposite of camouflaging it.
2) Loss of root length (root resorption) of the maxillary incisors. This is known to occur more frequently in Class II or Class III camouflage than in other types of orthodontic treatment. It reflects the amount of tooth movement that often is required, and the chance that the roots of the teeth (especially the upper incisors) will be thrown against the cortical plates of bone.

Question 15

What is the current trend with adult orthodontics?

Answer 15

It was rare in 1990 with 25% of patients being 19 or older.

The number has stayed constant but the proportion has decreased because more kids are getting orthodontic treatment.

Question 16

What is the motivation for adult orthodontic treatment?

Answer 16

2 categories:

To improve their present situation.

To keep what they have and maintain it.

Question 17

How is prevalence of periodontal pocketing signifying bone loss affected by age?

Answer 17

Doubles from 20 - 26, and doubles again by 33 - 39.

Odds are high that potential orthodontic patients will have some perio disease by age 30.

Question 18

What should be fixed prior to orthodontic treatment?

Answer 18

It’s critically important to be sure that periodontal disease is under control before any orthodontics begins–and periodontal problems, though perhaps of different types, are likely to be present in both younger and older adults.

Question 19

How does orthodontic treatment affect the periodontium?

Answer 19

Expansion of the dental arches stresses the gingival attachment and can lead to further loss of gingival tissue. Primary trouble area is the lower incisor region, where alignment of crowded incisors tends to move them facially.

Question 20

What periodontal considerations should be made for orthodontic treatment?

Answer 20

Perio disease should be under control prior to ortho treatment

Expansion of dental arches stresses the gingival attachment leading to further loss of gingival tissue

Effect of bone loss on the force needed for orthodontic tooth movement. (lighter forces needed in adults)

Question 21

What patient management factors are affected by orthodontic treatment?

Answer 21

Older patients tolerate treatment less. (expectations affect reaction to treatment. Let patients know itll hurt and provide medication for pain control)

Older patients are much more interested about their treatment and will ask more questions.

Question 22

How are upper incisors intruded?

Answer 22

Using a lingual arch.

Question 23

What is complex orthodontic treatment?

Answer 23

Extensive treatment that involves multiple dental specialties in addition to orthodontics.

Question 24

How should complex treatment be sequenced?

Answer 24

1) control active disease (extract hopeless teeth, perio treatment, endo treatment, restorations for caries control)
2) Correct the alignment and occlusion of the teeth and obtain acceptable dental aesthetics and facial proportions. (both orthodontics and orthognathic surgery can be done for this)
3) Definitive periodontics (long term maintenance via bone or soft tissue grafts) and definitive restorative dentistry (implants, onlays, or crowns)

Question 25

Is there any differences in moving endodontically treated teeth compared to normal teeth?

Answer 25

Response to orthodontics is the same, no conclusive evidence of a difference in root resorption following endodontic treatment and orthodontic treatment.

NOTE: orthodontic movement may be the last straw for a tooth with a traumatized or sensitized pulp. A patient with a tooth that may need endo treatment must be warned that it is possible for it to flare up and require treatment when orthodontics begins.

Question 26

Why should crowns be replaced on anterior teeth when correcting excessive overjet?

Answer 26

Often the crowns are made thick faciolingually in order to obtain occlusal contact of the incisors. Thick crowns make it impossible to correct overjet during orthodontic treatment.

Question 27

How should perio be managed in complex treatment?

Answer 27

It is critically important for patients with complex problems to be seen regularly for perio maintenance (2 - 3 month intervals).

Extraction of periodontically involved teeth with poor long term prognosis is indicated

Perio problems must be brought under control before ortho treatment and must be kept under control during ortho treatment

Question 28

When should definitive restorative work start in complex orthodontic treatment?

Answer 28

Careful coordination between the end of orthodontic treatment and the final restorative work is important. The time in orthodontic retainers before restorations are placed should be minimal. Waiting to start the restorative dentistry “until things settle down” is a recipe for problems.

Question 29

TRUE or FALSE: Mesial tilting of second molars in the upper arch does not compromise periodontal health of that tooth whereas it does in the lower arch.

Answer 29

TRUE; recent research has shown that unlike the lower arch, good periodontal health is possible with upper second molars tipped mesially

Question 30

Why are retainers necessary following orthodontic treatment?

Answer 30

Because orthodontic treatment outcomes are potentially unstable due to:

1) PDL and gingival tissues need time to reorganize after movement and removal of ortho appliance.
2) Pressure of tongue and lips/cheeks can cause tooth movement.
3) Growth after treatment can lead to adaptive changes in tooth position. (instability until growth is completed)

Question 31

What is active stabilization and how does it affect tooth movement?

Answer 31

Active stabilization is the stabilization of the uneven tongue/cheek forces by the PDL. This can create stability in the tooth but only works if the difference in tongue/cheek and lip pressure is a few grams.

Question 32

Why doesn’t reorganization fo the PDL occur until after the removal of orthodontic archwires?

Answer 32

Because splinting causes the teeth to move together and independent tooth movement is necessary for PDL reorganization.

Question 33

How long is retention needed after orthodontic treatment?

Answer 33

3 - 4 months for the PDL.

1 year for the gingival tissues. If the teeth were severely crowded/misaligned then another year of retention is likely needed.

Question 34

How fast do gingival tissues reorganize following orthodontic movement?

Answer 34

The gingiva contains both collagenous and elastic fibers, which reorganize more slowly than the PDL. At one year after alignment of the teeth the supracrestal elastic fibers still are stretched, particularly after a tooth has been rotated, and they exert enough force to cause immediate relapse.

Question 35

Severely rotated teeth are almost impossible to retain, what is done to prevent relapse?

Answer 35

A fiberotomy is used to relax the gingival elastic fibers.

Question 36

When is comprehensive treatment done for skeletal class II and deep bite problems?

Answer 36

During adolescence for 2 reasons:

1) Response to attempted growth modification is better then
2) Treatment often ends just as the growth spurt is about to end.

This is important because as the patient grows after taking off braces the original skeletal problem will start to reappear. For this reason, retention to maintain the jaw relationship and prevent lower incisor eruption will be needed until the growth subsides.

Question 37

Should the patient be wearing a retainer all the time as the braces are removed?

Answer 37

No, because the retainer would prevent the teeth moving in function which is necessary for PDL reorganization. Removable retainers should be taken out to eat and worn all the rest of the time.

Question 38

How is retention done for teeth to prevent movement caused by gingival elastic fibers?

Answer 38

Part-time retainer is worn 10 - 12 hours a day for the rest of the first post-treatment year.

Question 39

How is retention for tongue vs lip/cheek pressure done?

Answer 39

PDL can only retain up to a few grams after which long term retention will be needed,

Question 40

What does the typical retention schedule look like?

Answer 40

Full-time except during eating for the first 3 - 4 months

Part time for the next 8 - 9 months.

Continue part time until growth is complete.

If pressures are unbalanced continue indefinitely.

Question 41

How are 2 points of contact maintained during retention?

Answer 41

A retainer wire has to be contoured so that it follows the surface of the tooth.

Question 42

Why should a heavy wire retainer be bonded only to the canines?

Answer 42

So teeth can move relative to each other during function. They need to move in function.

Question 43

So what would be needed if you did want to attach the retainer wire to each incisor?

Answer 43

The wire would have to be small and flexible so that teeth can still move in function.

Question 44

What is the disadvantage of using small flexible bonded wires for retention?

Answer 44

If it debonds it can be an area of plaque accumulation and carious breakdown of the incisor.

Question 45

What are the types of removable retainers?

Answer 45

Wire that attaches to both facial and lingual surfaces.

Thermoplastic retainers which are suckdown plastic retainers

Question 46

Why is a maxillary central diastema hard to retain?

Answer 46

Usually there’s a defect in the bone between these teeth that prevents gingival elastic fibers from crossing the midline. The result is that, unlike every other location in the dental arches, there is nothing to keep the teeth together after the central incisors have been brought together.

Question 47

How are maxillary central diastemas retained?

Answer 47

The solution is a flexible wire bonded on the lingual. The space pops open as soon as there is nothing holding the teeth together, so a bonded flexible wire is by far the best retainer.

Question 48

Why is it not a good idea to use removable retainers for a central diastema?

Answer 48

A removable retainer moves the teeth back and forth a little every time it is placed or removed and that leads to continuing mobility and can cause root resorption and periodontal breakdown.

Question 49

How is overbite correction maintained?

Answer 49

A plate behind the upper incisors. It is easy to contour the anterior palatal portion of an acrylic retainer so that the lower incisors just touch it.

Question 50

Why is it important to maintain overbite correction?

Answer 50

The lack of incisor contact allows the lower incisors to over-erupt.

Question 51

Are suck-down retainers a good idea for patients who had excessive overbite?

Answer 51

No, because light contact of the plastic matieral with the facial and lingual surfaces of the teeth may not be enough to keep incisors from erupting.

Question 52

How is open bite correction maintained?

Answer 52

Often open bite is due to over eruption of posterior teeth rather than infra-eruption of anterior teeth.

Force to oppose eruption is created via a maxillary retainer over the occlusal surface.

NOTE: This can be effective for mild open bite problems but not patients with severe/long face growth pattern. Those patients may require retreatment after growth stops.

Question 53

How is class I occlusion maintained after correction of a skeletal class II problem?

Answer 53

A functional appliance is used where the patient bites into a predetermined position.