Vertical Dimension

Question 1

In high vertical discrepancy patients, the ___ is located lower down on the logarithmic spiral, suggesting that it could lead to early diagnosis of anterior open bite

Answer 1

Foramen ovale

Question 2

Anterior open items can be caused primarily dentoalveolar in nature (caused by habits) or related to skeletal morphology. The later may be caused by what two things?

Answer 2

Tipping upward of the palatal plane

Downward tipping of the mandibular plane due to dentoalveolar growth exceeding condylar growth, causing a backward and downward rotation of the mandible.

It has also been postulated that this may be a result of the interaction of the suprahyoid and infrahyoid muscles with the muscles of mastication creating an envelope of function with the resultant force directed through the antagonist notch area causeing the mandible to actually bend at the antagonist notch

Question 3

One of the characteristics of a hyperdivergent mandible is a deep ___ notch

Answer 3

Antagonial

Question 4

Generally, the use of anterior vertical elastics is contraindicated in skeletal open bites. Why?

Answer 4

Because often both the maxillary and mandibular incisors are over-erupted as opposed to being under-erupted in habitual open bite. Extrusion of incisors in these cases will lead to an unstable and unaesthetic result, as well as lip incompetency and the possibility of significant root resorption if vertical elastics are used for an unduly long period of time.

Question 5

When skeletal discrepancy for open bite is less severe, what are some possible treatment modalities?

Answer 5

Anterior vertical elastics
Posterior bite blocks
High pull headgear
Magnets to intrude molars
Extraction of teeth to close the “wedge
Vertical pull chin cup
NiTi wire and vertical elastics
Multiple loop arches and v. Elastics 
Functional appliances 
TADs to intrude molars

Question 6

Anterior openbite tendency is often associated with __ of the maxillary arch in conjunction with a ___ facial pattern.

In these. Cases, use of a bonded rapid maxillary expansion appliance with occlusal coverage rather than a banded appliance will be helpful in limiting molar ___ during expansion

Answer 6

Constriction

Dolichocephalic

Extrusion

Question 7

In skeletal open bite cases, why is a tongue habit corrector often necessary?

Answer 7

Although the tongue thrust isn’t the primary etiologic factor, it may prevent the correction of the open bite.

In many instances, correction of the anatomic imbalance will lead to spontaneous elimination of tongue thrust, however if is often necessary to use a habit appliance to prevent the tongue from obstructing teh correction if the habit is pernicious.

Question 8

True or false.. elastomeric ligatures attract significantly MORE plaque than steel ligatures.

Answer 8

True

Question 9

True or false.. self ligating brackets have significantly less plaque accumulation within the first 3 months of ortho treatment when compared to elastomeric ligated brackets

Answer 9

True. But, after 1 year of treatment, no difference in plaque accumulation was found

Because oral hygiene often tends to be better at the start relative to later in treatment, these results suffers that with good oral hygiene practices, self-ligation is advantageous relative to use of elastomeric. However if oral hygiene is poor, it doesn’t matter which type you use.

Question 10

When can orthodontic treatment be started on a patient who has been treated for periodontitis?

Answer 10

Following active periodontal treatment, patients in the maintenance phase of periodontal therapy traditionally are typically observed for 4-6 months before initiating orthodontic treatment. This provides time for full expressions of the benefits of the periodontal therapy

Once orthodontic treatment is started, periodontal maintenance should be scheduled at shorter intervals

Question 11

The most important etiologic factor in gingival recession relates to the…

Answer 11

Reduced thickness of the soft tissue and bone, especially on the facial surface of labially prominent teeth

This thin soft tissue and/or bone is a predisposing factor for gingival recession

Question 12

True or false… the thickness of keratinized tissue doesn’t matter whereas the height does. (In regards to gingival recession)

Answer 12

False

The apical-coronal height of keratinized tissue is not related to gingival recession, whereas the thickness of the keratinized tissue is an important factor.

Question 13

Orthodontic tooth movement in a facial direction of thin facial tissue can result in ____, creating an environment in which plaque and/or toothbrush trauma may cause sudden recession.

Answer 13

Bone dehiscence

Question 14

If a tooth is to be moved in a labial direction in an area with thin labial tissue, what should be done?

Answer 14

Gingival tissue should FIRST be augmented

Question 15

What may happen if maxillary expansion is performed after the mid-palatal suture begins to fuse (approximately 14-16 years of age)?

Answer 15

There is a greater risk later in life of recession of the buccal gingival tissue of the maxillary premolars and molars

Question 16

Treatment of class 2 fraction lesions in dog animal models demonstrated that a __-day delay in orthodontic movement did not interfere with healing or adversely impact the amount of bone regenerated by the regenerative periodontal techniques

Answer 16

60

Question 17

True or false… clinically, several case presentations have demonstrated that, following repair of osseous defects with GTR, orthodontic tooth movement can be accomplished without adverse effects on periodontal support. Similarly, teeth can be successfully moved into bone grafts of various types with no deleterious effects on tooth roots

Answer 17

True