Second Semester

Question 1

Describe the characteristics of a patient that would be at high risk of substantial external root resorption?

Answer 1

Already short roots

Conical/blunted root tips

Teeth need to be moved a long distance (closing extraction space)

Pt needs camouflage treatment (roots may bump against cortical plate)

Question 2

Describe the two normal postural lip positions

Answer 2

Relaxed: lips apart, relaxed, and hanging loosely with no contraction

Closed lip: lips are lightly touching to seal the oral cavity, minimal contraction to achieve this anterior closure

Question 3

Describe the abnormal lip position present in a class 2 div 1 case with significant overjet.

Answer 3

Closed lip: light contact between lower lip and maxillary incisors

Greater mentalis strain is noted to achieve closure

Question 4

Describe three techniques to find the relaxed lip position

Answer 4

For all three techniques, FH should be parallel to floor.

1) lightly jiggle mandible up and down as if trying to locate CR
2) Stroke the lips with fingers to relax lips and form the space between lips
3) instruct pt to relax lips

Question 5

Which is the least reliable method to find relaxed lip position?

Answer 5

Instructing the patient to relax their lips

Question 6

When evaluating lip posture should the teeth be together or apart?

Answer 6

Together

Question 7

The interlabial gap is influenced by what two things?

Answer 7

Length of the lips

Variation in skeletal height in the anterior portion of face

Question 8

It has been noted that the malocclusion with the shortest upper lip length is class ___

Answer 8

2 div 1

Question 9

A useful plane to evaluate lip protrusion is ____

Answer 9

Subnasale - soft tissue pogonion

Question 10

On average, the upper lip is ___ and the lower lip is ___ anterior to the subnasale-soft tissue pogonion line

Answer 10

3. 5mm

2. 2mm

Question 11

What is the typical angle for the nasolabial angle?

Answer 11

74 degrees

Question 12

The ___ should be considered the most important element in determining a stable position for the incisors

Answer 12

Lips

Question 13

True or false… a retruded lip pressed against a lower incisor is less suggestive of the desirability of protruding the lower incisor during treatment than a lip that is protruded and lying away from the incisor

Answer 13

True

Question 14

Normally, a relaxed lower lip will contact the ___ at the ___

Answer 14

Lower incisor

Junction of its incisal and middle thirds

Question 15

True or false… if the interlabial gap is large, protrusion of the teeth is more stable.

Answer 15

False

Question 16

Without considering growth, the most dramatic facial changes following retrusion of teeth are seen in cases where there is a ___

Answer 16

Large interlabial gap

Question 17

___ relaxed lip posture is associated with protrusive dentition and ___relaxed lip posture is associated with retrusive dentition

Answer 17

Protrusive

Retrusive

Question 18

Describe the lower lip resting position in Class 2 div 1 and Class 2 div 2.

Answer 18

Class 2 div 1: lower lip rests lingual to the upper incisors and exerts labial pressure

Class 2 div 2: lower lip rests labial to the upper incisors and exerts lingual pressure

Question 19

What is the soft tissue facial angle?

Answer 19

Angle between FH and line from soft-tissue nasion to soft-tissue chin

91+/- 7 degrees

Question 20

How did Holdaway measure nose prominence?

Answer 20

Line perpendicular to FH, tangent to vermillion of upper lip. Measure of tip of nose to this line

Normally 16mm . (<14 = small, >24 = large)

Question 21

How did Holdaway measure the superior sulcus depth?

Answer 21

Used the same line to measure nose prominence

3mm ideal (less than 1.5 should be avoided)

This is the most frequently criticized area with retraction of anterior teeth

Question 22

Holdaway found that upper lip thickness measured at the vermillion follows tooth movement. Notably, very thick lips (~__mm) will be slow to follow tooth movement, very thin lips (~___mm) will be fast to follow tooth movement

Answer 22

16mm+

12mm-

Question 23

The lips and chin should line up near the ___

Answer 23

H line

Question 24

What is the ratio for esthetic balance of upper face (glabella to subnasale) to lower face (subnasale to soft-tissue menton)?

Answer 24

1:1

Question 25

In repose, normally stomion superior to incisal edge is ___mm

Answer 25

1-5mm

Question 26

Smiling, the ideal maxillary incisor exposure is ____

Answer 26

3/4 of crown height to 2mm of gingiva

Question 27

The upper lip should be ___mm posterior to the E line. The lower lip should be __mm posterior to the E line.

Answer 27

4mm

2mm

Question 28

If a patient begins treatment with minimal display of the upper lip vermillion border, how might dental retraction produce a less esthetic result?

Answer 28

There will be some reduction in the display of the upper lip vermillion border

Question 29

If the patient’s initial incisor overjet was caused by extreme upper incisor proclination, then uprighting tends to cause ___. On the other hand If the initial incisor inclination was relatively normal and was retracted by translators movement it tends to cause ___.

Answer 29

Less lip change

More lip change

Question 30

There is [less/more] retraction of the upper lip when patients initially present with lip incompetence

Answer 30

More

Question 31

What type of radiographs are important in asymmetry cases, dental/skeletal crossbites, and functional mandibuar displacements?

Answer 31

PA and basilar cephs

Question 32

Natural head position is reproducible within a range of ___ degrees

Answer 32

2

Question 33

True or false… less exposure is needed for PA cephs than lateral cephs

Answer 33

False. More exposure is needed for PA cephs than lateral cephs

Question 34

How can vertical asymmetry be analyzed using a PA ceph?

Answer 34

Vertical asymmetry can be observed by connecting bilateral structures or landmarks, by drawing the transverse planes, and by observing their relative orientation

Question 35

In orthodontics, the primary indication for obtaining a PA ceph is ____

Answer 35

The presence of facial asymmetry

Question 36

Natural head position is important in all radiographs but even more -so in PA cephs. In a PA ceph, The ___ the distance between anatomic structures, the less the distortions are due to head positioning. The ___ the distance, the greater the distortions.

Answer 36

Shorter

Greater

Question 37

The FH plane is usually positioned parallel to the floor of the X-ray room. the upper margin of the petrous portion of the temporal bone (Porion?) passes through the ___of the ___

Answer 37

Middle to lower 1/3rd

Orbital cavity

Question 38

The floor of the nasal cavity is NOT flat. Therefore, the ANS and PNS are not superimposed in a PA ceph. If the head is tilted ____, the odontoid process is higher than the other structures and the PNS will be higher than the ANS. If the head is tilted____, the odotnoid process will be located below the ANS.

Answer 38

Downward

Upward

Question 39

If the upper facial height is longer than the lower part of the face in the PA ceph compared to the lateral ceph, then the subjects head was tilted ____ in the PA ceph. If the patient’s head was tilted ___, the entire PA ceph will show a longer facial image.

Answer 39

Upward

Downward

Question 40

In determining if a PA ceph was rotated, the ____should be clear and straight, if the patient was rotated it will become obscure. If the patient was rotated, the ___ appears different on both sides. It will appear wider on the side that is further from the film. There should be ____space between the maxillary alveolar bone and the inner surface of the ramus.

Answer 40

Nasal septum

Width of the ramus

Equal

Question 41

Only the ___of the pituitary fossa can be seen in a PA ceph

Answer 41

Floor

Question 42

In a PA ceph, labially inclined teeth give you a ___ image than lingually inclined teeth

Answer 42

Shorter

Question 43

Maxillary posterior teeth erupt in a ___ fashion while the mandibular posterior teeth erupt in a ____ fashion.

Answer 43

Straight downward

Lingually inclined

Question 44

The PA ceph is useful for two important diagnostic factors. What are they?

Answer 44

Assessment of symmetry

Measurement of the skull and denture widths (You don’t want to expand someone pas their cranial base.)

Question 45

True or false… all horizontal lines connecting bilateral cranial landmarks can adequately serve as reference lines in the PA analysis of vertical asymmetry, if acceptable landmark identification error

Answer 45

True

Question 46

The best vertical reference lines in PA cephs are perpendicular to horizontal lines connecting ___, if minimal landmark identification error

Answer 46

Bilateral cranial landmarks

Question 47

What are the three main limitations of PA cephs?

Answer 47

1) Difficulty in reproducing natural head position
2) Difficulty in landmark identification due to superimposed structures or poor radiographic technique
3) concern of radiation

Question 48

The preciseness of measurements of head films may be influenced by various errors such as…

Answer 48

Projection error

Landmark identification error

Measuring technique error

Question 49

In a PA ceph, the horizontal differences are larger if the landmark is located ____ from the vertical rotational axis and smaller if the landmark is located____ the vertical rotational axis.

Answer 49

Further

Nearer

Question 50

In a PA ceph, landmarks ___ to the vertical rotational axis move in the same direction as head rotation, whereas landmarks ___ to the vertical rotational axis move in the opposite direction as head rotation

Answer 50

Anterior

Posterior

Question 51

True or false… rotation of the head along the Y axis (head tilted side to side) does not cause distortion of the image

Answer 51

True because the location of the head is still parallel to the central ray

Question 52

True or false… in a PA ceph, tilting the head up or down (Nodding yes) does not significantly affect assessment of asymmetries of the face

Answer 52

True, because it will affect the relationship of landmarks vertically, not horizontally

Question 53

According to a s study by Peng L and Cooke, only 2/20 subjects showed changes in natural head position of ___ or more after ___ years

Answer 53

5 degrees

15 years

Question 54

True or false… natural head position has been shown to be remarkable reproducible even after 15 years. It is a more reliable reference plane for cephalometric analysis than intracranial reference planes

Answer 54

True

Question 55

What is the difference between natural head position and natural head orientation?

Answer 55

NHP: Taken when subject is looking at a distant point at eye level

NHO: Position the orthodontist believes the pt’s head would be if they looked straight ahead at a distant point at eye level

Question 56

____ is a significant factor in affecting natural head orientation (not NHP).

Answer 56

Chin position

The validity of NHO in diagnosis and treatment planning is therefore questioned.

Question 57

True or false, the curvature of the mandibular canal and third molar tooth germ can serve as natural references for superimposition of the mandible

Answer 57

True

Question 58

Radiographic cephalometry superimposition is limited by what 5 problems?

Answer 58

1) headfilms taken at different times are difficult to reproduce with any degree of accuracy
2) the double images of bilateral structures are not consistently equally spaced in serial headfilms because of faulty head positioning
3) Film contrast and density differences
4) Anatomical or structural landmarks not consistently identifiable
5) 3d changes are only measured in 2d

Question 59

For overall craniofacial growth, displacement, and treatment effects, one should superimpose on ___ registering at ____.

Answer 59

SN (sella-nasion) line

Sella

Question 60

For maxillary complex growth and treatment effects, the best fit for superimpositioning is on the _____

Answer 60

Palatal surface of the maxilla parallel to ANS-PNS

Question 61

For mandibular growth and treatment effects, one should superimpose on the ____ of the ___ and on the ___.

Answer 61

Lingual contour

Symphysis

Inferior alveolar canal

Question 62

True or false… superimpositions are not completely accurate but are valuable when assessing overall change due to growth and treatment

Answer 62

True

Question 63

Define natural head position

Answer 63

The position of the head with the subject standing and the visual axis parallel to the horizontal plane

Question 64

Overtime, does NHP tend to result in patient looking slightly up or down?

Answer 64

Slightly down

Both Sagittal and transversal NHP have been shown to be reproducible after 2 years

Question 65

What are the four positions in Rickett’s four step method to distinguish orthodontic changes from natural growth?

Answer 65

Chin
Maxilla
Maxillary teeth
Mandibular teeth

Question 66

___ degree is a useful rule for expected variation of the chin (due to natural growth/development) over a two-year treatment period. Therefore, if a patient under treatment opens up more than ___ degrees, there is a high change that the orthodontic treatment caused the opening.

Answer 66

1

2

Question 67

A change in the maxilla evaluating the Ba-N-A angle during treatment can be assumed to be due to ___ and not ___.

Answer 67

Treatment

Growth

Question 68

Rickett’s position three (relative to maxillary teeth), consists of superimposing the ___ and ___, registered at ___. This is considered a ___ position naturally, meaning…

Answer 68

ANS
PNS
ANS

stable

Any backward or forward change in teeth in 2 years can be attributed to treatment, not growth

Question 69

Abnormally enlarged sella turcica, poorly defined posterior and anterior clinoid processes, and short cranial base are all findings that indicated a problem with the ___

Answer 69

Pituitary gland

Question 70

Individuals with ____ have increased incidence of cervical spine abnormalities

Answer 70

Cleft lip/palate

Question 71

What is an odontoidium?

Answer 71

It is a potentially fatal developmental spinal abnormality

When the body of the odontoid process and axis have separated, which can lead to subluxation of C1 or C2, which may cause spinal cord damage

On a lateral ceph it appears as a small, ovoid radiopacity superior to the arch of C1 and odontoid process

Question 72

In orthodontics, when should cephs be examined for pathology?

Answer 72

Prior to beginning treatment

Question 73

The radiographic shape of the sella turcica is highly variable. What are the three basic shapes?

Answer 73

Oval
Circular
Flat

Question 74

What are four possible radiographic indications of pathology of the sella?

Answer 74

Double floor

Thinning or ballooning of floor

Erosion of the lamina dura

Erosion of the dorsum sella

Question 75

What is the most common cause of an enlarged sella?

Answer 75

Primary intrasellar pituitary tumor

Question 76

According to a study on the frequency with which an orthodontist can expect to discover pathology, remarkable radiographic findings were reported in ___% of cases.

Answer 76

6.2%

Question 77

What is the most commonly reported finding reported from orthodontic radiographs?

Answer 77

Mucous retention cysts

They are frequently non-pathologic, yet they can be associated with symptoms

Question 78

A ___ approach should be used when examining radiographs for pathology.

Answer 78

Systematic

Question 79

Because of individual variation, physiological and anatomical maturity cannot be assessed accurately by chronically age alone. Better parameters of anatomical maturity include…

Answer 79

Growth velocity
Secondary sex changes
Dental development
Skeletal ossification

Question 80

Orthodontists do not necessarily need to know the exact skeletal age of a patient. Instead, what is important to know for the orthodontist?

Answer 80

Whether will patient will grow at all during a 1-2 year treatment period and what percentage of growth can reasonably be expected during that time.

Question 81

A study by Lamparski (1972) concluded that the cervical vertebrae (as viewed in lateral ceph) were _____ in assessing skeletal age as the hand wrist technique

Answer 81

As statistically and clinically reliable

Question 82

Describe the initiation cervical vertebral stage (SMI 1 and 2).

Answer 82

The vertebrae are wedge-shaped, with the superior vertical borders tapering from posterior to anterior. 80-100% of adolescent growth can be anticipated at this stage.

Question 83

Describe the acceleration cervical vertebral stage (SMI 3-4).

Answer 83

Growth acceleration begins at this stage when 65-85% of adolescent growth can be anticipated. Concavities develop on the inferior borders of C2 and C3. The bodies of C3 and C4 are nearly rectangular, and the inferior border of C4 is flat.

Question 84

Describe the Transition cervical vertebral stage (SMI 5-6).

Answer 84

Adolescent growth accelerates toward peak velocity, with 25-65% of adolescent growth anticipated. Distinct concavities develop on the inferior borders of C2 and C3. A concavity begins to develop on the inferior border of C4, and the bodies of C3 and C4 are rectangular

Question 85

Describe the Deceleration cervical vertebral stage (SMI 7-8).

Answer 85

Only 10-25% of adolescent growth remains. Clear concavities are seen on the inferior borders of C2, C3, and C4 with the bodies of C3 and C4 becoming more square-like.

Question 86

Describe the Maturation cervical vertebral stage (SMI 9-10).

Answer 86

Final maturation takes place at this stage, when only 5-10% of adolescent growth can be anticipated. Accentuated cavities are seen on the inferior borders of C2, C3, C4, and the bodies of C3 and C4 are nearly square.

Question 87

Describe the Completion cervical vertebral stage (SMI 11).

Answer 87

Little to no adolescent growth is expected at this point. Deep concavities are seen on the inferior borders of C2, C3, and C4, and the vertebral bodies are more vertical than horizontal.

Question 88

True or false… the cervical vertebrae technique in assessing growth status is race-neutral

Answer 88

True

Question 89

Four ossification stages of bone maturation in the hand wrist radiograph are evaluated at ____ anatomical sites located on the ___, ___, and ___. ___ skeletal maturation indications are found on these sites.

Answer 89

6

Thumb
Third finger
Fifth finger

11

Question 90

What are the four ossification stages on a hand-wrist radiograph?

Answer 90

Epiphyseal widening on selected phalanges

Ossification of adductor sesamoid of the thumb

‘Capping’ of selected epiphyses over their diaphysis

Fusion of selected epiphyses and diaphyses

Question 91

Describe SMI 1-3 in a hand-wrist radiograph

Answer 91

Width of epiphysis as wide as diaphysis

1. 3rd finger - proximal phalanx
2. 3rd finger - middle phalanx
3. 5th finger - middle phalanx

Question 92

Describe SMI 4 in a hand-wrist radiograph

Answer 92

Ossification

4. Adductor sesamoid of thumb

Question 93

Describe SMI 5-7 in a hand-wrist radiograph

Answer 93

Capping of epiphysis

5. 3rd finger - distal phalanx
6. 3rd finger - middle phalanx
7. 5th finger - middle phalanx

Question 94

Describe SMI 8-11 in a hand-wrist radiograph.

Answer 94

Fusion of epiphysis and diaphysis

8. 3rd finger - distal phalanx
9. 3rd finger - proximal phalanx
10. 3rd finger - middle phalanx
11. Radius

Question 95

What is the first step in evaluating a hand-wrist radiograph?

Answer 95

Evaluate if adductor sesamoid of the thumb is visible or not.

If not visible, applicable SMI will b associated with early epiphyseal widening rather than caping

If visible, either the sesamoid or an SMI based on capping or fusion will be applicable

Question 96

In a hand-wrist radiograph, at SMI 6, all values showed about __% completion of adolescent growth

Answer 96

50%

Question 97

True or false… facial growth shows a close direct association between variations in the rate of growth in skeletal maturation

Answer 97

True

although maxillary and mandibular growth rates peaked later than statuary height and statuary height demonstrated a greater percentage of completed growth than facial growth in the middle to late adolescent growth period

Question 98

True or false… tooth development criteria are sufficiently reliable to indicate the pubescent growth spurt.

Answer 98

False.

Question 99

____ mineralization appears to correlate better with ossification stages than other teeth.

Answer 99

Mandibular canine

Question 100

The ____ phalanx shows the highest relationship with canine maturity

Answer 100

Third middle

Question 101

Bjork, and others, found that capping of the epiphyses of the ___ phalanx was closely related to the pubertal maximum growth velocity

Answer 101

Third middle

Question 102

Mandibular canine stage ___ indicates the initiation of puberty. Canine stage ___ is consistent with capping of the third middle and fifth phalanges and the presence of the adductor sesamoid, indicating PHV. Describe these canine stages.

Answer 102

F: walls of pulp chamber form an isosceles triangle with apex ending in a funnel. The root length is equal to or greater than the crown height.

G: the walls of the root canal are now parallel and its apical end is partially open

Although there is a close association between mandibular canine calcificaiton stages and skeletal maturity, canine calcificaiton should not be the sole criteria to predict PHV

Question 103

Most studies have found that the growth height peak corresponds with ___ and __ peak growth

Answer 103

Maxillary

Mandibular

Question 104

Cervical stages __ through ___ are pre peak growth and accelerative growth phase. Cervical stages ___ through ___ are post peak growth and decelerative growth phase. Peak growth occurs between CVs __ and ___.

Answer 104

1-3

4-6

3 and 4

Question 105

Cervical stage ___ is the closest stage to the onset of peak growth.

Mean age for girls is ___ -___
Mean age for boys is ___-___

Answer 105

3

8.6-11.5 years old

10-14 years old

Question 106

____ growth peak during the transition from CVs3 to CVs4 corresponds with ___ growth peak

Answer 106

Statural height

Mandibular

Question 107

Does the mandible and midface more closely follow the neural growth curve or the somatic growth curve?

Answer 107

Somatic

Question 108

The craniofacial complex phenotype is a result of the ___ and the ___ and ___ environment

Answer 108

Genome

Intrinsic

Extrinsic

Question 109

Normal ___ is greatest in early development and reduces with maturation

Answer 109

Adaptation

Question 110

What are three factors that affect whether the craniofacial skeleton will respond positively to orthodontic-orthopedic treatment?

Answer 110

1) Availability of precursor mesenchymal stem cells (tissue type)
2) Capability for growth factor expression (developmental age and sex)
3) Local environment (treatment duration and mechanics)

Question 111

The conclusion of a study by Dolce et al (2005) was that the skeletal effects of ____ treatment disappear by the end of fixed appliance treatment (phase 2)

Answer 111

Phase 1 class 2

Question 112

In a multicenter study conducted in the UK, early orthodontic treatment with the twin-block appliance resulted in substantial reduction in the ___ of children with class 2 malocclusion that was mainly due to ___ changes. The results of the study reinforce others by suggesting early functional appliances do not, on average, influence the class 2 skeletal pattern to a ___ degree

Answer 112

Overjet

Dentoalveolar

Clinically significant

Question 113

According to a study by Tulloch et al, the advantage created during phase one class ___ treatment was lost and by the end of fixed appliance treatment there was no significant differences between any of the groups for all AP and vertical skeletal and dental measures.

Answer 113

2

Question 114

In the study conducted by Tulloch et al, evaluating phase 1 class 2 treatment, there was no statistically significant difference in scores comparing the children who had early treatment and those who did not. There was no statistically significant effect related to the ____.

Answer 114

Orthodontist

Question 115

Early treatment of ____ has little effect on the subsequent treatment outcomes measured as skeletal change, alignment, and occlusion of the teeth, or the ___ and complexity of treatment

Answer 115

Class 2

Length

Question 116

Early Phase 1 treatment of class 2 might be no more clinically effective than a single compressive phase started during ____. Early treatment also appears to be less efficient in that it….

Answer 116

Adolescence in the early-permanent dentition

Produces no reduction in the average time a child is in fixed appliances during the second stage of treatment and it does not decrease the proportion of complex treatment involved extractions or orthognathic surgery

Question 117

True or false… early treatment of class 2 (phase 1) decreases the length and complexity of phase 2 treament when compared to a single comprehensive treatment.

Answer 117

False

Early class 2 treatment is NOT an efficient way to treat most Class 2 cases

Question 118

What are three therapies that may increase the stability of open-bite treatment in cases with abnormal tongue function?

Answer 118

1) Crib or sharp spur therapy (1-2 years)
2) Myofunctional therapy
3) Partial glossectomy

Question 119

True or false… tonsillectomy and/or adenoidectomy have been shown to consistently improve the stability of open bite treatment in scenarios where the patient has allergies and/or enlarged adenoids

Answer 119

False.

Question 120

Is early orthodontic treatment indicated for anterior open-bite malocclusions?

Answer 120

Yes, but it depends on many factors like severity, age, etiology, and parental concerns

Question 121

Is stability of open bite treatment a clinical problem?

Answer 121

Yes

Question 122

True or false… you can use a quad helix or reverse pull facemask with skeletal effects if the patient is in cervical stage 1 or 2

Answer 122

True

Question 123

If the patient is in cervical stage 3, when are they expected to experience peak growth?

Answer 123

Within the year

Question 124

True or false… you can use a quad helix with skeletal effects if the patient is in CS3

Answer 124

False, probably. Best to use a hyrax in this stage

Question 125

What are four factors that can affect the amount of upper lip change when incisors are retracted?

Answer 125

Lip length

Lip toxicity

Lip thickness

Interlabial gap (incompetent lips will be affected more than competent lips)

Question 126

True or false… every person has a certain degree of lip protrusion that will not be affected by the presence or absence of teeth

Answer 126

True.

Question 127

What is the H line?

Answer 127

H line = Harmony line (developed by Holdaway)

Runs from soft tissue pogonion to the vermillion of the upper lip

Used to assess the protrusion of the lower lip and the concavities found below the lower lip or above the upper lip.

Question 128

When Holdaway was constructing his VTO, he concentrated on the ___ and ___

Answer 128

Upper incisors

Lips

Question 129

SMI ___ of the hand-wrist radiograph is associated with peak jaw growth velocity

Answer 129

7

Question 130

In a study by Franchi and McNamara styling the long term effects of RPE, craniofacial structures [near/far] from the nasomaxillary area show the following changes:

Overall changes in RPE group [exceeded/were less than] those in the control.
There were significant [increases/decreases] in EU width (transverse cranial measurement), Lo width, and Mmd width.

Answer 130

far

exceeded

increases

Question 131

Long-term effects of RME appear to involve an ample portion of the ___ with enhanced transverse growth of these regions

Answer 131

craniofacial complex

Question 132

True or false… in the long-term (~8 years post expansion), the effects of RME with the Haas appliance followed by fixed appliance therapy can induce normalization of both dental and skeletal components of the craniofacial complex

Answer 132

true

Question 133

____ is lost during the transition from mixed dentition to permanent dentition, particularly in the ___ arch.

Answer 133

Arch length

mandibular

Question 134

According to a study by Gianelly, when crowding was not associated with early loss of ____, leeway space provided adequate space to correct crowding in 82% of cases

Answer 134

primary canines

Question 135

According to one study: Theoretically, maintaining leeway space will resolve ___ of crowding cases in the mixed dentition. According to a second: clinically, maintaining leeway space resolved ___% of crowding cases

Answer 135

72%

68%

Question 136

Timing of treatment to resolve crowding should be a the terminal phase of ___. However, what is one major exception? How should this be treated?

Answer 136

the mixed dentition

If a primary canine is loss too early, it will require immediate intervention to control both arch length and symmetry. The contralateral primary canine should also be extracted and lingual arch should be placed

Question 137

RPE increases the perimeter of the maxillary arch and can correct __-__mm of crowding

Answer 137

3-4mm

Question 138

What does the data say about spontaneous expansion of the mandibular arch as a result of REP?

Answer 138

Although some expansion of the mandibular arch may occur, it provides almost no space to resolve crowding in the lower arch

Question 139

According to Grayson (1977), “the use of rapid palatal expansion as a method of increasing lower arch length [cannot/can] be justified

Answer 139

cannot

(while 1mm increase of lower inter canine dimension can provide 0.73mm of space to correct lower incisor position, 1mm of molar expansion only provides 0.27mm of space. )

Question 140

According to Gianelly, it is unreasonable to justify the use of RPE in the absence of crossbones, particularly because…

Answer 140

any correction of the molar relationship could be unstable

Question 141

A meta-analysis evaluating the immediate changes with RPE found that the greatest dental and skeletal changes were in the ___ dimension and occurred at the ___.

Answer 141

transverse

dentition

This confirms previous studies that RME produces more tipping than true palatal expansion but some skeletal expansion was still noted

Question 142

According to a metaanalysis, RPE expansion was greater [anteriorly/posterior] because…

Answer 142

the RME appliances were anchored on posterior teeth

Question 143

According to a meta-analysis, RPE [increases/decreases] overate by ___

Answer 143

increases

1.29mm

Question 144

According to a meta-analysis evaluating the impact of RME on OSA, studies indicate that there is a decrease in ___ after maxillary expansion in children with OSA. Studies suggest that the decrease is [lost/maintained] over 3-14 years

Answer 144

AHI (Apnea-hyopnea index)

maintained

Question 145

What are three theories explaining why there is a decrease in AHI after RME in children with OSA?

Answer 145

RME decreases nasal resistance and facilitates the passage of air through the nose

increases the maxillary dental arch, improving the position of the tongue enabling proper sealing of the lips

indirectly increases the oropharyngeal space

Question 146

True or false… The use of RME in children with OSA appears to be an effective treatment

Answer 146

true

Question 147

Class 3 malocclusion affects between __-__% of our population

Answer 147

5-15%

Question 148

Studies have reported that treatment of class 3 malocclusion should be carried out in patients less than ___ years of age to dance the orthopedic effect

Answer 148

10

Question 149

True or false… there is moderate evidence to show that early treatment with a facemark results in positive improvements in both skeletal and dental changes in the short term. however, there is lack of evidence for the long-term benefits

Answer 149

true

Question 150

In a study evaluating the affects of extractions on airway, initial and final volumes and the minimal cross-sectional areas [were/were not] statistically significantly different fro the nasopharyngeal, redropalatal, retroglossal, and total airway regions between the extraction and non extraction groups

Answer 150

were not

Question 151

True or false… dental extractions in conjunction with orthodontic treatment have a negligible effect on the upper airway in adults

Answer 151

true

Question 152

What are 5 recommendations if auto-transplantation is to take place?

Answer 152

1) extraction should be done ataumatically
2) extra-alveolar time minimized as much as possible
3) Iatrogenic damage at the recipient site should be prevented by minimizing the fitting attempts
4) Donor tooth should be fixed in infra occlusion to prevent postoperative occlusal forces
5) suture splint is advised because this decreases the chance of ankylosis compared with a more rigid splinting system

Question 153

What can happen if a pt is on bisphosphonates with orthodontic treatment?

Answer 153

can inhibit tooth movement

increases risk of osteonecrosis

Question 154

What are bisphosphonates used to treat and how do they work?

Answer 154

used to treat bone metabolism disorders (osteoporosis, bone diseases, bone pain from certain cancers)

inhibit bone resorption by osteoclasts

Question 155

what is the most common bisphosphonate?

Answer 155

fosamax (alendronate)

Question 156

True or false… you should avoid orthodontic treatment if the patent has taken oral bisphosphonates

Answer 156

not necessarily. you should avoid it if they are on IV bisophosphnotates. But if they are on oral bisphosphonates, treatment may be challenging and you should still watch for signs and symptoms of osteonecrosis.

Question 157

What are some signs and symptoms of osteonecrosis?

Answer 157

excessive tooth mobility

exposed necrotic bone

non-healing bone after extractions

teeth not moving as they should

Question 158

True or false.. fixed orthodontic appliances have no power to change the airway volume; this fact is supported in the literature, showing that there is no strong evidence that orthodontic treatment has a significant effect on the pharyngeal airway, even when associated with extractions and despite the changes in incisor angulation and position.

Answer 158

true

Question 159

Even though the patient is instructed to follow a series of instructions during a lateral ceph scan, changes may still happen possibly caused by…

Answer 159

different breathing stage

swallowing

craniocervical posture

Question 160

In a study evaluating the long-term comparison of nonextraction and premolar extraction therapy in borderline class 2 patients, how did the pattern of relapse compare between the two groups? How was the patient’s perception of esthetics different ?

Answer 160

Pattern of relapse was essentially identical between the two groups

There was no significant difference in lower incisor crowding and no significant difference in patients’ perception of esthetics.

Question 161

True or false… there is a single optimal incisor position/angulation that ensures long term stability in class 2 extraction cases.

Answer 161

False. There is a range of positions that will serve the patient

Question 162

The more the mandible outgrows the maxilla the upper molars and upper incisors will tip ___ and the lower incisors will tip ___. Lower molar anchorage will be ___.

Answer 162

Forward

Lingually

Preserved

Question 163

For borderline patients, nonextraction treatment produced a significantly more protrusive denture of __mm.

Answer 163

2mm

Question 164

True or false… the pattern of relapse in extraction or nonextraction of borderline cases is unrelated to the type of treatment

Answer 164

True. Dentoalveolar compensation produced by differential jaw growth following treatment

Question 165

True or false… there is no evidence that either treatment (ext or non-ext of borderline cases) produce distal displacement of the basal bone of the mandible or its condyle

Answer 165

True. There is no evidence

Question 166

True or false… with a flatter profile, extraction patients viewed their outcome as a failure compared to nonextraction patients.

Answer 166

False. Despite flatter profile, extraction patients were as likely as the nonextraction patient’s to view their outcome as an improvement

Question 167

True or false… there has been found to be a slight increase in mandibular intercanine width in extraction patients. On the other hand, intermolar width seems to decrease in both jaws

Answer 167

True

Question 168

In a study conducted by Herzog et al (2017), the mean change values for the maxillary and mandibular intercanine widths of both extraction and non extraction patients, showed…

Answer 168

No statistically significant difference. However,the mean change values of the intermolar widths were significantly different

Question 169

The findings of Herzog (2017) indicate that in borderline patients, the choice whether to extract has no impact on the ____of the maxillary and mandibular arches

Answer 169

Intercanine widths

Question 170

The study by Herzog (2017) found significant differences between treatment groups (ext and non ext) regarding ___ changes. Describe these changes.

Answer 170

Intermolar width

there are smaller arch widths with extraction treatment than non-extraction. This finding can be attributed to the forward movement of the first molars in extraction patients

Question 171

Herzog (2017) found in borderline cases, the maxillary and mandibular arch perimeter to decrease in the ___ group, whereas the ___ group showed no significant difference in arch perimeter before or after treatment

Answer 171

Extraction

Non-extraction

Question 172

True or false… Herzog (2017) found the intercanine width of both extraction and nonextraction borderline cases to increase significantly.

Answer 172

True

Question 173

how does intercanine width increase in extraction treatment? How does the intermolar width decrease?

Answer 173

The distalization of the canines into a wider part of the dental arch during canine retraction.

The intermolar width decreases by anterior movement of the molars during space closure

Question 174

Overall, in non-ext patients, post-retention of ___ width is more stable than ___width

Answer 174

Intermolar

Intercanine

Question 175

Extraction treatment leads to decreased maxillary and mandibular ____ when compared with non-ext treatment. Meanwhile, ___ showed no significant difference between the two groups.

Answer 175

Intermolar and perimeter measurements.

Intercanine

Question 176

In the extraction group (Herzog 2017), ____ increased, ___ showed no significant change, and ___ and ___ decreased

Answer 176

Intercanine width

Maxillary intermolar width

Mandibular intermolar width and arch perimeters

Question 177

In the non extraction group (Herzog 2017), significant changes of ___ occurred, whereas ___ were maintained.

Answer 177

All arch-width measurements

Arch perimeters

Question 178

The data from Gianelly 2003 indicates that ____ are not the expected consequence of extraction treatment. Therefore, the esthetically compromising effect of ___ on smiles is not a systematic outcome of extraction treatment.

Answer 178

Narrow dental arches

Narrow dental arches

Question 179

According to a study by Bowman, the two panels both rated ___ treatment as having little esthetic effect throughout the full range of pretreatment profiles. ____ had the potential to improve or worsen the profile depending on the patient’s initial protrusion

Answer 179

Nonextraction

Premolar extraction

Question 180

In Bowman’s study, extraction treatment has a ___% probability of producing an improvement in facial esthetics, despite producing an average of __mm less lip protrusion than nonextraction. Nonextraction has only a ___% likelihood of improving facial esthetics.

Answer 180

50-60%

1.8mm

30-50%

Question 181

The esthetic effect of treatment on the facial profile is a function of ___, ___, and ___

Answer 181

The type of treatment

Initial protrusion of the profile

Background of the observer

Question 182

In a study by Bowman, profiles of extraction patients that initially had lower lip protrusion ___ behind the E-line were worsened by treatment

Answer 182

2-3mm

Question 183

What are the 3 leading reasons for extractions in orthodontics in order?

Answer 183

Crowding
Incisor protrusion
Profile improvement

Question 184

Studies have indicated that __% of interproximal enamel can be safely removed.

Answer 184

50%

Question 185

True or false… males have more interproximal enamel than females

Answer 185

False. There is no statistically significant difference in mesial or distal enamel thickness between sexes

Question 186

With the exception of the ___, ___ enamel demonstrates significantly greater enamel thickness than ___

Answer 186

Second premolar

Distal

Mesial

Question 187

Name three potential iatrogenic effects of IPR

Answer 187

Increased incidence of caries

Temperature sensitivity

Periodontal disease

(However these effects may not be seen as frequent in anterior)

Question 188

IPR may be indicated in individuals with… (4 things)

Answer 188

1) good OH
2) class 1 arch length discrepancies with orthognathic profiles
3) minor class 2 dental malocclusions (particularly non-growing pts)
4) Bolton tooth size discrepancies

Question 189

IPR is well suited for patients with arch discrepancies less than the size of ___

Answer 189

Two premolars

Question 190

Even patients with the thinnest enamel could expect to gain __mm with 50% IPR in 8 posterior contacts

Answer 190

7mm

Question 191

Mandibular incisor relapse appears to be minimal when nonextraction treatment is used with ____

Answer 191

Palatal expansion

Question 192

Premolar extraction reduces soft and hard tissue convexity by ___mm whereas nonextraction therapy has little effect. In general, _____ changes (including an additional convexity reduction) are about the same in both groups.

Answer 192

2-3mm

Post-treatment

Question 193

When growth is finished, clear-cut [extraction/nonextraction]patietns tend to have “flatter” profiles than do ___ patients who present with ____

Answer 193

Nonextraction

Premolar extraction

Significant crowding and spacing

Question 194

Pre-and post-treatment tooth movements tend to be related to the pattern of ___; some forms of relapse therefore, may be a dentoalveolar compensation for residual posttreatment growth

Answer 194

Jaw-growth

Question 195

A study by Little found that average treatment time for serial extraction was 12 months vs nearly twice that time for ____

Answer 195

Late extraction

This suggests serial extraction may require more observation visits but fewer months of active treatment

Question 196

What are the three clinical implications discussed by Little regarding serial extractions?

Answer 196

1) possibly improved periodontal health if anteriors were not allowed to crowd
2) reduced treatment time but patients did require supervision during the mixed dentition pre-appliance stage
3) Often serial extraction procedures were required prior to first premolar extraction in order to guide the developing dentition vs a single extraction surgery in the late extraction group

Question 197

There is ___ anchorage needed for four premolar extraction treatment of class 2 vs two premolar

Answer 197

2x more

Question 198

In a study by Janson, treatment with 2-PM extraction provided better occlusal success rates compared to 4-M due to what 4 factors?

Answer 198

1) final TPI (treatment priority index) was significantly smaller and change during tx was significantly greater
2) Final bilateral canine AP discrepancy was significantly smaller and change during tx was significantly greater
3) Final overjet was significantly smaller
4) final overbite was significantly smaller and change during tx was significantly greater

Question 199

Describe the differences in ABO scores observed in patients treated with or without extractions

Answer 199

There was no statistically significant difference

Question 200

Describe the differences in extraction vs nonextraction treatment that were found between the scores of the 8 ABO variables.

Answer 200

No statistically significant differences were found

Question 201

The variable of ___ received the poorest grade and appears to complicate orthodontic treatment the most

Answer 201

Buccolingual inclination, through which torque control of the posterior segment is assessed,

Question 202

True or false… class 1 patients treated with or without extractions of 4 first premolars have similar probabilities of passing the ABO exam

Answer 202

True

Question 203

What was concluding in a study comparing linear and angular measurements on panos taken at different times (Stramotas)?

Answer 203

Comparing linear and angular measurements on panos taken at different times is sufficiently accurate for measuring changes in root length and root parallelism, to assess sites for implant location, and to measure angulation of developing third molars (provided the occlusal plane is kept at similar angulation and not tilted>10degrees)

Accurate measurement of structures on panoramic images is possible, provided sufficient care is taken with head positioning

Question 204

Teeth with abnormally shaped ___ have a greater risk of root resorption

Answer 204

Apices

Question 205

What are the first and second most common resorbed roots in orthodontic treatment?

Answer 205

Maxillary lateral incisors: most common resorbed teeth, also highest rate of dilaceration

Maxillary central incisors: second most common resorbed teeth, highest incidence of point teeth

Question 206

True or false.. it is more difficult to assess root shape on a panoramic film compared to peri-apical films

Answer 206

True

root that had abnormal shape on PA were rated normal shape on pano

Question 207

Overall apical resorption shows to be [greater/lesser]on panoramic films compared to periapical films. Why?

Answer 207

Greater

Severity of root resorption may be over exaggerated due to patient positioning and focal trough aligned with maxillary dentition.

Periapical films provide a more detailed view of alveolar bone and root.

Question 208

If initial and final panoramic films are used to assess the amount root resorption, it may be exaggerated by ___% or more. ____ are especially vulnerable to distortion

Answer 208

20%

Mandibular incisors

Clinicians should check panoramic films carefully and order PA films if roots cannot be visualized. Also receommend PA films on patients with higher risk of root resorption or bone loss

Question 209

The most frequent errors occurring in panoramic radiography occur because of ___. Describe the frequency of these errors.

Answer 209

Patient positioning

14% chin too low
4% head tilted
4% head turned
1% chin too high

Question 210

The clinical assessment of ____ tooth angulation with panoramic radiography should be approached with extreme caution, with an understanding in of the inherent image distortions that are further complicated by the potential for aberrant head positioning

Answer 210

Mesiodistal

Question 211

Panoramic radiography visualizes the ___ and ___ of the TMJ and does not visualize the ___. A study by Epstein confirms that panos can show ___-___ bony abnormalities. However, they did not provide information that influenced ___ in the majority of cases

Answer 211

Lateral slope and central positions

Articular eminence and fossa

Moderate-severe

Diagnosis/patient management

Question 212

The presence of atheromatous plaque in the carotid artery of clinically asympotmatic individuals is often associated with the later development of ___, __, and ___

Answer 212

Cerebrovascular disease

Coronary artery disease

Death

Question 213

41% of patients with carotid calcifications had a ___% death rate during an average 3.6 year follow up

Answer 213

15%

Question 214

Name 8 factors to consider when evaluating buccal-bone thickness in CBCT scans

Answer 214

1) voxel size
2) spatial resolution
3) partial volume averaging
4) noise
5) gray scale
6) tooth rotations
7) RAP (regionally acceletory phenomenon)
8) statistical power

Question 215

What are the most common voxel sizes used for routine orthodontic scans? What spatial resolution does this allow? Can this be used to adequately visualize thin bone?

Answer 215

0.3mm and 0.4mm. Rendering an average spatial resolution of 0.7mm which is no adequate to properly visualize thin bone.

Question 216

In a CBCT, scatter levels increase as the size of ___ increases.

Answer 216

Field of view

Question 217

Current CBCT systems range from __ to __ bit gray scale, but the human eye cannot distinguish past ___bit. What should be used when evaluating buccal bone on a CBCT?

Answer 217

12-16

10

Highest available grey scale

Question 218

How should you account for tooth rotations when evaluating buccal bone thickness in a CBCT?

Answer 218

Make multiple measurements around the tooth and average them for a more accurate representation of bone support regardless of tooth rotations

Question 219

Describe RAP (regionally accelatory phenomenon) and its affect on CBCT scans.

Answer 219

It is a tissue reaction to a noxious stimulus that increases the healing capacities of the affected tissues. This occurs with orthodontic tooth movement when alveolar bone undergoes constant bone turnover and reduces the density of the active bone.

Since CBCT scans identify an object by its density, bone undergoing RAP would appear more radiolucent

Question 220

How long should you wait after orthodontic treatment to evaluate buccal bone thickness with a CBCT? Why?

Answer 220

At least one year

RAP takes 6-24 months to fully subside after the end of tooth movement. RAP can affect the CBCT scanner’s ability to accurately depict the bone.

Question 221

Name 6 recommendations when evaluating buccal bone thickness in a CBCT.

Answer 221

1) Use a smaller voxel size than standard orthodontic voxel size (<0.3mm)
2) reduce noise by using the smallest FOV possible and removing metal brackets/bands
3) Increase scan time
4) use a 16-bit sensor for the best gray scale
5) Factor in tooth rotations (average multiple bone thicknesses)
6) wait at least one year post-treatment to minimize influence of RAP

Question 222

True or false… CBCT scans for routine orthodontic purposes are adequate to accurately evaluate buccal bone changes

Answer 222

False

Question 223

Labial impatient of canines occurs in about __% of patients with the most common treatment being ___ and ___

Answer 223

Excisional gingivectomy

Apically positioned flap

Although, closed-eruption technique is believed by some to be superior especially for teeth that are impacted high above the mucogingival jnction or deep within the alveolus

Question 224

A ___flap is used in the apically positioned flap technique of canine exposure. What occurs after the flap?

Answer 224

Split-thickness

Once reflected, bone that was covering the enamel is removed until 2/3rd of the crown is exposed and the CT follicle is curettes from the periphery of the exposed portion of the crown. Then surgical dressing is placed over enamel to ensure tissue does not grow over the enamel. Then surgical dressing is removed and orthodontist bonds attachment 2 weeks after surgery

Question 225

Labially impacted maxillary anterior teeth uncovered by ___ have more unesthetic sequalae than those uncovered by ___

Answer 225

Apically positioned flap

Closed-eruption technique

Question 226

What are four negative esthetic effects when an apically positioned flap is used to expose a canine?

Answer 226

Increased crown length
Increased width of attached tissue
Gingival scarring
Intrusive relapse

Question 227

Closed-eruption technique is typically superior to the apically positioned, flap, however if a tooth requires ___ or is displaced ____, an apically positioned flap may be the best choice.

Answer 227

More attached gingiva

Lateral to the edentulous area

Question 228

A study by Vermette (1995) found a significant number of ___ relapse cases within the apical positioned flap cases that were not seen in the closed-eruption groups. What might be an explanation?

Answer 228

Vertical

Once the flap is positioned apically, the gingiva heals to the new positions, which could be far above the mucogingival junction. When the teeth are erupted into occlusion by orthodontic forces the gingival tissue will stretch , which causes complications for fighting relapse

Question 229

A study by Vermette (1995) found that for the ____, the gingival margin was located significantly more apical, the clinical crowns were longer, more attachment was lost on the facial surface, and more bone was lost on the mesial, facial, and distal surfaces.

Answer 229

Apically positioned flap

Question 230

Describe the two methods of surgical exposure for palatally impacted canines.

Answer 230

Open exposure: traction is placed after the canine erupts freely into the palate

Closed exposure: placement of an auxiliary attachement, followed by traction of the canine with ortho forces

Question 231

What are the advantages of open exposure of palatally impacted canines?

Answer 231

Fewer subsequent re-exposures

Shorter treatment time

Improved hygiene during treatment

Question 232

A study by Schmidt concluded that treating palatally impacted maxillary canines with ____, ___, and ___ has minimal effects on the periodontist

Answer 232

open surgical exposure

natural eruption of the canine

orthodontic alignment

Question 233

The study conducted by Schmidt found that roots of impacted canine and the adjacent lateral incisor were ____ than those of the contralateral control teeth, and no significant ___ changes were identified.

Answer 233

slightly shorter

pulpal

Question 234

True or false… in the study by Schmidt, visual differences were not apparent in the previously impacted tooth when compared with the contralateral control canine

Answer 234

false. visual differences were present

Question 235

___ are the second most commonly impacted permanent tooth. 1/3rd are located ___, and 2/3rds are located ___

Answer 235

maxillary canines

labially or within the alveolus

palatally

Question 236

What are two options to attempt to enhance eruption of labially impacted canines without surgical uncovering?

Answer 236

extraction of primary canine (8-9 years old)

mechanically open space with orthodontics

Question 237

What are the three techniques for uncovering a labially impacted maxillary canine?

Answer 237

excisional uncovering

apically positioned flap

closed eruption techniques

Question 238

What are four criteria to consider when determining the method of uncovering of a labially impacted canine?

Answer 238

labiolingual position of impacted canine

vertical position of impacted canine relative to mucogingival junction

amount of gingiva in the impacted canine area

mesiodistal position of the impacted canine

Question 239

If a maxillary canine is impacted labially, any of the three exposure techniques can be used, however if the canine is located in the center of the alveolus, only the ___ technique can be used. Why?

Answer 239

closed eruption technique

the excisional approach and apically positioned flap would need extensive bone removal

Question 240

Which exposure technique must be used if an impacted canine crown is apical to the MGJ? Why?

Answer 240

closed eruption technique

Excisional technique would be inappropriate because there would be no gingiva over the labial surface after it has erupted. apically positioned flap would be inappropriate because crown instability and retrusion relapse after treatment

Question 241

If the crown of an impacted maxillary canine is mesial and over the lateral root, you should use the __ technique

Answer 241

apically positioned flap

Question 242

Why should you avoid mechanics that draw an impacted canine labially?

Answer 242

it could cause dehiscence and labial recession

Question 243

If the permanent canine was positioned over the ___ but not past the ___, self correction occurred with high predictability if primary canines were removed

Answer 243

root of the lateral incisor

mesial surface of the root

Question 244

If an impacted canine, in which surgical exposure has been performed, does not appear to be moving, what could be the cause?

Answer 244

problem is usually insufficient bone removal over impacted canine crown

impacted canine crowns are often in contact with the lingual surfaces of the central and lateral incisor roots

actual ankylosis of maxillary canines is low likelihood

Question 245

When impacted canines are dragged across the lingual surface of lateral incisor roots, what may occur?

Answer 245

root resorption of lateral and canine

bone levels of distal of lateral and mesial of canine were more apical compared to contralateral non impacted teeth

Question 246

How can treatment time, and periodontal and esthetic results be improved with palatal impaction of canines?

Answer 246

early uncovering using a full-thickness mucoperiosteal flap and allow canines to erupt on their own to the level of the occlusal plane in 6-8 months. Then a bracket is placed and the canine is brought into the arch

Question 247

Maxillary canine impaction occurs in __% of the population. it occurs twice as often in ___vs ___, ___ vs ___, and ___ vs ___. There is a 2.4x increase chance of palatally impacted canines when missing ___

Answer 247

2%

females vs males

maxilla vs mandible

palatal vs labial

lateral incisors

Question 248

Only ___% of labially displaced canines have sufficient space for eruption vs ___% of palatal canines

Answer 248

17%

85%

This shows that arch length discrepancy is the primary factor for labial canines, yet the etiology of palatally impacted canines is not known

Question 249

What are some palatally impacted canine theories?

Answer 249

Guidance theory: canine guidance is guided along the root of lateral incisor, if root is absence or malformed, canine will not erupt.

Genetic theory:

Question 250

What are the sequelae of impacted canines?

Answer 250

usually asymptomatic

can cause migration of neighboring teeth and loss of arch length

root resorption of surrounding teeth

increased risk of cysts and infection

Question 251

What are 5 clinical signs of a palatally impacted canine?

Answer 251

1) delayed eruption
2) over-retention of primary canine
3) absence of labial bulge (around 9-10 years old)
4) presence of palatal bulge
5) distal crown tipping of lateral incisor

Question 252

Extracting primary canine before patient is 11 years old will result in ___% success rate if crown is distal to midline of lateral root and ___% if crown is mesial to midline of lateral root. Probably of successful eruption decreases as ___ and ___ increase

Answer 252

91%

64%

horizontal angulation and overlap

Question 253

What are the three steps to bring in an impacted canine?

Answer 253

1) create space in arch for impacted canine
2) Surgically expose the tooth
3) apply force to erupt the tooth (avoid contacts with roots of other teeth)

Question 254

What is the simplest way to reduce the frequency of canine impaction?

Answer 254

timely extraction of primary canines

Question 255

What are some less common etiologies behind impacted canines?

Answer 255

1) supernumerary tooth or odontomas
2) cysts
3) hx of trauma

Question 256

___-___% of canine impaction cases are unilateral

Answer 256

60-75%

This gives question to the genetic theory or canine impaction because you would expect more bilateral cases. Also identical twins were shown to have same incidence of ectopic canines as fraternal twins, opposing the genetic theory. C

Question 257

True or false… the eruption of the canine is strongly influenced by environmental factors

Answer 257

true

although hereditary effects may be associated, genetics shouldn’t be warranted as the underlying cause of canine impaction

Question 258

A study by Armi (2011) showed that maintenance or improvement of the perimeter of the upper arch as a measure to intercept palatal displacement of maxillary canines is ____in preventing impaction of palatally displaced canines

Answer 258

effective

Question 259

True or false.. the use of RME and headgear in palatally displaced canine cases increases the success rate of eruption of the canine

Answer 259

true

almost three times more than in untreated controls

Question 260

True or false.. the prediction of the probability of canine impaction based on CBCT is excellent

Answer 260

true

Question 261

What are the strongest predictors based on CBCT radiographs to identify to probably of impaction?

Answer 261

canine angulation to the lateral incisor on the coronal view

canine cusp tip to the occlusal plane on the sagittal view

canine crown position

Question 262

Describe the radiographic appearance of teeth undergoing root resorption. How do they look after termination of active orthodontic therapy?

Answer 262

Rough, jagged and notched root contours. Widened PDL space that accentuated the rough appearance.

Jagged edges become smooth. Sharply pointed root ends rounded with time

Question 263

Does root resorption continue even after the orthodontic appliance is removed ?

Answer 263

no

Question 264

What are the two types of internal root resorption?

Answer 264

apical

intraradicular (more rare)

Question 265

What are the two types of intradicular internal root resorption?

Answer 265

inflammatory resorption

replacement resorption

Question 266

What are the three requirements for internal root resorption to occur?

Answer 266

Damage of odontoblast layer in plural canal wall

bacterial stimulus

viable blood supply apical to resorptive lesion

Question 267

What is the difference between internal inflammatory resorption and internal replacement resorption?

Answer 267

In inflammatory resorption the resorptive space is filled with granulation tissue

in replacement resorption the resorptive space is filled with metaplastic tissue that may resemble bone or cementum

Question 268

What is the treatment that should be done with teeth diagnosed with internal root resorption?

Answer 268

Root canal treatment

early detection and intervention improves prognosis

Question 269

What causes the resorption in internal root resorption?

Answer 269

clastic cell action (odontoclasts)

Question 270

If the internal root resorption is located in the coronal part of the canal ___ can be observed.

Answer 270

a pink spot in the crown

Question 271

What are the therapeutic options for treating teeth with internal root resorption?

Answer 271

1) monitor (in absence of infectious signs and symptoms)
2) RCT (use MTA if perforation has occurred)
3) retrograde apical treatment
4) extraction

Question 272

A study by Kurol et al (1998) found that there may be a relationship between root resorption and ___ in the PDL

Answer 272

hyalinized areas

Resorption cavities are seen close to the over-compressed zones. But, about half of the hyalinzed areas were NOT associated with root surface resorptions

Question 273

Generally, it is believed that hyalinized zones are due to ___ of the PDL. Even with initially _____ hyalinization and root resorption must be expected.

Answer 273

over-compression

light orthodontic forces below 50gm

Question 274

What is inflammatory external root resorption?

Answer 274

The intermediate cementum layer that caps dentinal tubules will resorb the inflammatory response is large or there is serious trauma.

if pulp is infected, bacterial byproducts can become the source of ongoing increased root resorption

can be arrested by endodontic therapy

More frequent in younger implanted teeth

Question 275

Another term for replacement resorption is ___

Answer 275

ankylosis

Question 276

Describe the etiology of replacement resorption

Answer 276

extensive damage to the PDL will cause PDL to become nectroic

Alveolar bone will replace the attachment and resorb the root and will result in dentin fused to bone

clinically, ankylosis will have a metallic sound on percussion and a moth-eaten look radiographically

Question 277

true or false… external root resorption can occur from pulp necrosis and periradicular pathosis

Answer 277

true

Question 278

External resorption from pressure in the PDL can occur without orthodontic treatment most frequently in which areas?

Answer 278

maxillary laterals by canines

mandibular second molars from the third molars

Question 279

What is cervical resorption? What causes it?

Answer 279

A progressive external inflammatory resorption that occurs just below the epithelial attachment or more apical on the root surface where damage to the PDL or cementum has occurred

Can be caused by: orthodontics, trauma, internal bleaching, periodontal treatment, orthographic or dentoalveoalr surgery, and idiopathic causes

if resorption infiltrates the crown, the cervical coronal enamel may appear pink in color

Question 280

Some degree of orthodontically induced external root resorption is expected to occur in __% of patients

Answer 280

80%

Question 281

A ___mm loss of root length due to OIERR is biomechanically equivalent to ___mm loss of crestal alveolar bone loss

Answer 281

3mm

1mm

Question 282

Severe OIERR is considered to be a loss of ___mm or more than ___ of the overall root length.. It is estimated to affect up to ___% of orthodontically treated patients

Answer 282

> 4mm

1/3rd

15%

Question 283

[continuous/interrupted] forces induce more OIERR than [continuous/interrupted] no matter the force level

Answer 283

continuous

interrupted

Question 284

Which causes more root resorption?

Heavy or light forces?

Intrusive or extrusive forces?

Short or long treatment duration?

What are the effects of bracket prescription, wire sequence, and ligation method?

Answer 284

Heavy

intrusive

long

bracket prescription, wire sequence, and ligation method had no differences in OIERR

Question 285

What are the three treatment options for congenitally missing lateral incisors?

Answer 285

Canine substitution

single-tooth implants

tooth-supported restorations (full coverage FPD, cantilevered FPD, Marylin bridge)

Question 286

In order to treat a patient with congenitally missing lateral incisors with canine substitution, the patient ideally has….

Answer 286

small canines that are the same shade as the central incisors

nice profile

class 2 dental relationship

no crowding in the dental arch

Question 287

Greater bucco-lingual alveolar width for implant placement of lateral incisors can be established if….

Answer 287

the permanent canine erupts in the lateral incisor position and then is moved distally into place

otherwise the edentulous site is typically deficient

Question 288

Implant placement in a narrow ridge requires ____ to prevent dehiscence and results in ____

Answer 288

deeper placement

thin facial bone which can lead to a show-through of the implant body/abutment (new zirconia implant abutments may help so the implant isn’t as noticeable)

Alveolar ridge augmentation is needed for a stable overlying esthetic soft tissue framework

Question 289

Bone loss near an implant is worse if the implant to tooth distance is

Answer 289

1.5mm

PAs of the edentulous area must be taken before removing orthodontic appliances to confirm ideal root position and adequate spacing for implant placement

Question 290

The timing of implant placement for missing lateral incisor is based on the patient’s facial growth. If it is placed before growth is completed it can lead to periodontal, occlusal, and esthetic problems. It can typically be based at age __ for males, and ___ for females. describe the most predictable way to monitor facial growth for implant placement.

Answer 290

20-21 years

16-17 years

Take serial cephs every 6 months to year apart. implant can be placed if 2 sequential radiographs show no growth

Question 291

What could happen if a patient uses a flipper for too long instead of getting an implant for their missing lateral incisor?

Answer 291

The central incisor and canine roots can converge overtime

Question 292

A resin-bonded FPD (Marylin bridge) is the most conservative approach of the tooth-supported restorations for replacing a missing lateral incisor. What are three contraindications for this method? Describe the ideal patient.

Answer 292

Contraindications:

1) deep bite
2) proclined teeth
3) mobility of abutment teeth

Ideal:

1) non-bruxer
2) upright incisors
3) immobile abutment teeth
4) shallow overbite

Question 293

A cantilevered FPD to replace a missing lateral incisor is more predictable than a resin-bonded FPD. Why is the ___ the ideal abutment tooth?
What is the key to long-term success using this approach?

Answer 293

Canine

because of its root length and crown dimensions

removing all excursive contacts

Question 294

What are the two types of malocclusion that permit canine substitution?

Answer 294

Class 2 with no mandibular crowding

class 1 with severe mandibular crowding warranting extractions

Question 295

Naturally, the canine is ___ shades darker than the lateral incisor

Answer 295

1-2

you can individually bleach the canine or veneer it to better match the adjacent teeth

Question 296

What are four characteristics of an ideal canine to be used for lateral incisor substitution?

Answer 296

1) same color as central incisor
2) is narrow at the CEJ BL and MD
3) has relatively flat labial surface
4) has narrow crown width BL

Question 297

You should position the gingival margin of the canine slightly ___ to the central incisor gingival margin to help camouflage the substituted canine. therefore, you should place the brackets according to the ___ rather than the ___

Answer 297

incisal

gingival margin height

incisal edge/cusp tip

Question 298

In canine substitution, as the canine erupts, periodic equilibration during alignment stage is necessary. why?

Answer 298

A thicker portion of the canine will contact the mandibular incisors

Question 299

___% of wisdom teeth either fail to erupt or only partially erupt

Answer 299

24%

more common in lower jaw

Question 300

True or false… all third molars should be extracted prophylactically

Answer 300

false.

there is insufficient evidence to either support the removal or retention of asymptomatic, disease-free impacted wisdom teeth

Question 301

What are the main soft tissue and hard tissue conditions associated with third molars that would necessitate their removal?

Answer 301

pericornitis and infection

periodontal disease

dental caries

odontogenic cysts and tumors

Question 302

There is a higher likelihood of pericornitis in ___ positioned lower third molars at or near the level of the occlusal plane and in ___ cases with ___ positioned third molars

Answer 302

vertically

ortho-treated

mesioangular

Question 303

True or false.. it has been shown that periodontal status of second molar improves over time after third molar removal

Answer 303

true

Question 304

True or false… third molar sites commonly harbor microbial flora known to be associated with periodontal disease, and evidence suggests that third molar sites may first be affected by periodontitis that moves to more anterior locations overtime

Answer 304

true

Question 305

True or false… remineralizing capacity of fluoride is generally accepted, but evidence is insufficient to support effectiveness of remineralization of post-ortho WSLs

Answer 305

true

Question 306

True or false… studies have shown that CPP-ACP can promote remineralization of subsurface lesions, but current evidence is insufficient to prove a clinical benefit on post-ortho WSLs

Answer 306

true

Question 307

What are 8 guidelines (Kokich 1997) to assist clinicians when planning interdisciplinary treatment. If orthodontists and restorative dentists do these things, the esthetic and occlusal outcome of their combined efforts will be greatly enhanced.

Answer 307

1) establish realistic objectives
2) create a diagnostic set-up
3) determine the sequence of treatment
4) build-up malformed teeth
5) position teeth to facilitate restorative treatment
6) evaluate gingival esthetics
7) take progress radiographs
8) interact during finishing

Question 308

The first step in any type of dental therapy is to ___.

Answer 308

establish treatment objectives

It is impossible to achieve the correct end result if the appropriate goals or objectives have not been identified before treatment

Question 309

____ treatment objectives may not be appropriate for the orthodontic-restorative patient. for these types of patients, it is important to…

Answer 309

Idealistic

establish realistic, not idealistic treatment objectives

Question 310

Realistic treatment objectives fall into three categories. what are they?

Answer 310

economically realistic

occlusally realistic

restoratively realistic

Question 311

A ___ is mandatory for any patients who are missing multiple permanent teeth and who will require a combination of orthodontics and restorative dentistry

Answer 311

diagnostic was set-up

Question 312

A team of specialists must not only establish a realistic plan of treatment but they should also…

Answer 312

determine the sequence of interaction between different specialists

This is a critical step that should occur before the initiation of therapy. A copy of the sequence should be given to each of the participating dentists.

Question 313

What are two common situations in which teeth must be built-up before, during, or after orthodontic therapy?

Answer 313

retained primary teeth

peg-shaped lateral incisors

Question 314

With retained primary, mandibular central incisors, maxillary lateral incisors, and maxillary canines, what should be done if these teeth are to be retained until replacement with implant?

Answer 314

they should be built-up mesiodistally to preserve space for the implant.

It is often necessary to create a diagnostic wax-up to simulate the correct width of the composite restoration. some of these primary teeth can be retained indefinitely

Question 315

If sufficient space exists to do a composite restoration of a peg lateral before orthodontic treatment, should it be performed before or after orthodontic treatment?

Answer 315

before

However, in most situations, there is insufficient space to restore the malformed lateral incisors. therefore, orthodontics is often necessary to create space to build up peg laterals

Question 316

If a patient has a normal lateral incisor on one side, but a peg lateral on the other, how much space should be created for the restoration of the peg lateral?

Answer 316

A little extra space than the normal lateral incisor, because it will allow the restorative dentist to contour and polish the interproximal surfaces of the restoration.

Question 317

The ___ surfaces of central and lateral incisors are more contoured or convex. Therefore, the peg-shaped lateral incisor should be positioned ____ during orthodontic treatment for the best composite restoration

Answer 317

distal

nearer the central incisor than the canine

Question 318

where should the lateral incisor be positioned in the buccolingual orientations for the restoration with a crown? What about a porcelain veneer?

Answer 318

center of the ridge BL (this will avoid additional tooth preparation on the lingual of the lateral)

Further lingually to contact the mandibular incisor in centric occlusion. (This will allow sufficient space on the labial to construct both the temporary composite build-up and the eventual porcelain laminate)

Question 319

where should a peg lateral be positioned incisogingivally for restoration?

Answer 319

the relationship is determined by the position of the gingival margins

Question 320

When making the decision to restore a peg-lateral, several concerns must be addressed. what are 3 concerns?

Answer 320

1) cervical portion of the peg lateral is usually narrower MD (restoration will be over-contoured)
2) life of the restoration (using a veneer instead of a crown would increase the longevity of the tooth because it will likely need to be restored multiple times throughout life)
3) esthetics.

Question 321

Periodontal surgery can be performed to improve the length of clinically short crowns. If the bone is located near the CEJ, ___ will be necessary. If the bone is ___mm away from the CEJ, a ___ is sufficient.

Answer 321

osseous surgery

1-2mm

simple gingivectomy

Question 322

If a conventional FPD is going to be used to replace a missing lateral incisor, the orthodontist should create ___ of overjet at the end of treatment

Answer 322

0.5mm - 0.75mm

Question 323

How should you treat an adult patient with worn and shortened incisors?

Answer 323

intrude the incisors by placing the brackets slightly more incisally.

posterior teeth will be anchors to facilitate intrusion of the incisors and will lead to an open bite (which is what you want)

After the appropriate gingival margin relationships have been achieved 1) remove brackets, 2) restore incisal edges, 3) replace brackets and complete orthodontic treatment

Question 324

Why should you intrude incisors that have wear on the lingual surfaces and which are planned to have crowns?

Answer 324

to create space for restorations

Question 325

The gingival margins of the lateral incisors should be __ ___ to the central incisor. the canine gingival margins should match the central incisors

Answer 325

0.5mm

incisal

Question 326

If teeth have __mm of sulcular depth and the gingival margins are at different levels, the patient should be referred to a periodontist to perform gingival surgery [before/after] bracket removal

Answer 326

> 1mm

before

Question 327

As the central incisor and canine are pushed apart, what may occur which would make it impossible to place an implant for the missing lateral incisor?

Answer 327

the apices of the roots converge. Therefore, radiographs must be taken to ensure the roots have moved out of the way

Question 328

If the patient will require restorations after orthodontics, when should the orthodontist send the patient to the restorative dentist?

Answer 328

during the final 6 months of treatment

Question 329

True or false… orthodontic space closure of missing lateral incisor space is reasonably stable and better accepted by patients than prophetic replacements (not including implants).

Answer 329

true

pts with prosethsic replacement tend to have impaired periodontal health with acculumuation of plaque and gingivitis.

Question 330

Does canine substitution impair TMJ function

Answer 330

no

Question 331

What is the H-line and how is it measured?

Answer 331

Harmony line, created by Holdaway

measured from most prominent part of upper lip to the soft tissue pogonion.

Used to evaluate soft tissue protrusion of the lower face, including the lips. And the upper and lower lip sulci

Useful because it does not depend on the size of the nose (which is highly variable)

Question 332

The interlabial gap is affected by what four things?

Answer 332

lip length

protrusion of the teeth

tonicity of the lips

skeletal (vertical) relationships

Question 333

how do you determine the prognosis of impacted maxillary canines regarding vertical position?

Answer 333

best - tip of canine at CEJ of adjacent teeth

Worst - tip of canine less than 1/3 from apex of adjacent teeth

Question 334

How do you determine the prognosis of impacted maxillary canines regarding horizontal position?

Answer 334

best - less than half of the distance across the root of the lateral

worst - more than half the distance across the lateral

Question 335

How do you determine the prognosis of impacted maxillary canines regarding angulation?

Answer 335

best - less than 30 degrees

worst - more than 45 degrees

Question 336

How do you determine the prognosis of impacted maxillary canines regarding crowding?

Answer 336

best - mild/moderate spacing

worst - crowding in anterior leaving no room to move teeth out of the way of erupting canine

Question 337

how do you determine the prognosis of impacted maxillary canines regarding the age of the patient?

Answer 337

best - less than 12 years old

worst - greater than 18 years old

Question 338

What percentage (range ) of patients have some sort of radiographic pathology?

Answer 338

4-6%

Question 339

What are the big 3 reasons to extract?

Answer 339

crowding

proclination of incisors

improve profile

Question 340

What are some secondary reasons to extract?

Answer 340

• camouflage tx
• preparation for surgery
• attempt to deepen bite
• questionable prognosis of teeth
• asymmetric extraction to correct midlines or if there are missing teeth

Question 341

patients with thick lips (___) have minimal changes to profile due to extractions. patients with thin lips (___) have significant changes to profile with extractions.

Answer 341

18+mm

12-mm

Question 342

Statural growth [proceeds/follows] maxillary and mandibular growth by about ___ months

Answer 342

proceeds

6

Question 343

True or false… it is difficult to predict growth for an individual but you can predict a population pretty well with some standard deviations

Answer 343

true

Question 344

True or false… by the time girls’ permanent teeth are in they are typically past their peak growth

Answer 344

true

boys will typically have all their permanent teeth in when they are going through peak growth. Therefore, it is typically easier to do growth modification on boys than girls.

Question 345

When is the most efficient time to treat transverse or maxilla AP deficiency?

Answer 345

pre-peak growth

Question 346

when is the most efficient time to treat class 2?

Answer 346

right at or slightly before peak growth

Question 347

True or false… all peak growth velocity occurs between C3 and C4

Answer 347

false. although most people’s peak growth velocity occurs here, for some people it occurs between C4-C5

Question 348

True or false… early class 2 growth modification is not effective at all

Answer 348

false. it is effective in that it does correct the class 2. but it is not efficient because that improvement will not last. It is not any more effective than just doing it later during comprehensive treatment during adolescent growth spurt. This means early class 2 treatment can still be used in special indications such as trauma or bullying

Question 349

True or false… you should only expand in phase 1 if the patient has a crossbite with a functional shift

Answer 349

false.. if they have a deficient maxilla (lower molars are tipped lingually and walla ridges are tight), expansion is done much easier in phase 1 when patient is young. Additionally, if you burn off the primary roots or get recession of gingiva of primary teeth, it doesn’t matter

Question 350

True or false… with class 2, but not class 3 molar finish you must use 0-offset bracket/bands

Answer 350

false. you have to use 0-offset for BOTH class 2 or class3 molar finish

Question 351

What is the “biggest struggle” with 2 upper premolar extractions for class 2 camoflauge treatment according to Minick?

Answer 351

biggest struggle with 2 premolar extractions is keeping the torque with the upper incisors and not let too much crowding in the mandible cause the lower incisors to flare. If you upright the upper incisors as you retract them and let the lower incisors flare you will run out of functional overjet and still have spaces to close. You may think you have a bolton discrepancy, but you don’t.

Question 352

True or false… it is much easier to maintain torque than to regain it

Answer 352

true

A 19x25 wire in a 22 slot will cause you to lose torque when retracting upper incisors

Question 353

With Dr. Minick if you see an impacted canine, you should take a CBCT. Why?

Answer 353

You can’t really tell where the canine is or its angulation from pano or PAs and you certainly can’t tell the damage that has already been done. most laterals and 10% of centrals already show damage in a CBCT

Question 354

what are the max limits of an enlarged sella. if it is larger than these measurements then it is concerning and should be evaluated.

Answer 354

AP = 16mm

Depth = 12mm

Question 355

what is a sponylolisthesis?

Answer 355

a “step” between the vertebrae. can lead to hernia of disks

Question 356

looking at a hand-wrist radiograph when does female peak statural growth occur?

what about males?

Answer 356

female SMI = 5

male SMI = 6

Question 357

Looking at a hand-wrist radiograph when does female peak jaw growth occur? what about males?

Answer 357

female SMI = 6

male SMI = 7

Question 358

Skeletal changes require what three things?

Answer 358

1) precursor mesenchymal stem cells
2) capability for growth factor expression
3) local environmental factors (ortho tx)

Question 359

strongly consider extracting primary canines if permanent canines are impacted (but its success depends on the angulation and horizontal overlap of the canine). ___% successful if canine tip is distal to middle of lateral root. ___% successful if canine tip is mesial to the middle of lateral root.

Answer 359

91%

64%

Question 360

Headgear with our without RME significantly increases the rate of palatal canine eruption by ___

Answer 360

3x