Orthodontics - ABGD Oral Boards Flashcards

1
Q

Where are the primate spaces?

A
  • Maxillary Primate Space distal to laterals
  • Mandibular Primate Space distal to canines
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2
Q

How many mm is Incisor Liability in primary dentition in the maxilla?

A

7.0 mm

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3
Q

How many mm is Incisor Liability in primary dentition in the mandible?

A

6.0 mm

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4
Q

How man mm is Transient Mandibular Crowding?

A

0 - 2.0 mm

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5
Q

What happens to primary teeth as they transition to the permanent dentition?

A
  • Interdental spacing in primary dentition
  • Increase in intercanine width (2 mm)
  • Slight labial positioning of the incisors (1 - 2 mm)
  • Distal shift of canines as primary first molars are lost (md/1mm)
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6
Q

What is Leeway Space?

A
  • Mesial/Distal size difference between the primary molars and canines and permanent premolars and canines
  • 1.5 mm maxillary arch per quadrant or 3 mm per arch
  • 2.5 mm mandibular arch per quadrant or 5 mm per arch
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7
Q

What accounts for the “E” space?

A

Most of the space is due to the size difference in the second primary molars

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8
Q

What are the 3 Primary Second Molar relationships?

A
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9
Q

What are 3 factors that influence the first permanent mlar relationship?

A
  • Early mesial shift
  • Late mesial shift
  • Differential growth
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10
Q

What types of occlusion will primary distal step, flush terminal plane, and mesial step typically transition into in the permanent dentition?

A
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11
Q

What does a Flush Terminal Plane Typically transition into?

A
  • Most develop into Class I relationship (75%)
  • Not stable and may develop into Class II relationship
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12
Q

What Molar Class is this?

A

Class I Molar

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13
Q

How do you develop a Class I Molar Relationship?

A

Early Mesial Shift

  • Flush primary second molars
  • Space primary dentition (priamte spaces)
  • Normal eruption pattern-mandibular first molar migrates mesially to close primate space
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14
Q

How else can you develop a Class I Molar Relationship?

A

Late Mesial Shift

  • Flush primary second molars
  • Closed primary dentition (no primary spacing)
  • Class I conversion via leeway space
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15
Q

When you have a Mesial Step, what permanent dental occlusion is likely?

A

Mesial Step

  • Class I or Class III
  • Dependent upon extent of step seen clinically and patient’s growth pattern
  • Refer for early evaluation (by 8 years)
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16
Q

What type of occlusion is this?

A

Class III

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17
Q

What type of adult occlusion will a Distal Step typically evolve into?

A

Distal Step

  • Usually develops into Class II skeletal and dental malocclusion
  • Flush terminal plane plus factors which reduce arch length
  • Refer for early evaluation
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18
Q

What’s the difference between Class 2 Div I and Class 2 Div II?

A
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19
Q

What type of occlusion is this?

A

Class II Div I

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20
Q

What type of occlusion is this?

A

Class II Div 2

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21
Q

Which teeth most commonly show Ectopic Eruption?

A
  • Maxillary First Permanent Molars
  • Incisor
  • Canines
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22
Q

What % of Ectopic Eruptions self correct?

A

60%

  • If not, may continue to resorb primary molar or impact permanent tooth
  • Preserve primary second molar if possible
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23
Q

What is going on here?

A

Ectopic Eruption

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24
Q

How can you treat Ectopic Eruption?

A

Separators

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25
Q

Describe the Radiographic Method of Space Analysis…

A
  • Requires undistorted periapical radiographs
  • Requires Algebra…solve for uknown!!!
  • Casts
  • Calipers

True width of primary molar/Apparent width of primary molar

=

True width of unerupted premolar/Apparent width of unerupted premolar

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26
Q

What are some space analysis names that have Proportionality Formulas?

A

Tanak and Johnston

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27
Q

Describe the Tanaka-Johnson Formula…

A
  • No radiographs
  • Predicts both arches
  • Reasonably good correlation
  • Data obatined from Caucasion population, may not be approppriate for all ethnicities
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28
Q

What is a Combination medthod of Space Required Analysis?

A

Hixon/Oldfather, revised by Staley/Kerber

  • Periapical radiographs of premolars and canines
  • Proportionality tables
  • Highly accurate - but tables developed from Caucasian children of European ancestry
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29
Q

What are 3 key recommendations for Mixed Dentition Space Analysis?

A
  • High-quality periapical radiographs can be difficult to obtain on children
  • Tanaka-Johnston formula has good accuracy and is very convenient
  • May need to resort to radiographs, however, if patients are not Caucasian
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30
Q

What is the Bolton Tooth Size Analysis?

A

Evaluation of the mesial/distal tooth size discrepancies between maxillary and mandibular arches

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31
Q

What is the formula for the Bolton Space Analysis?

A
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32
Q

Describe the Interpretatin of the Bolton Space Analysis…

A
  • Disproportion will be expressed in mm of either…
  • Excess
  • Deficiency
  • It is up to the dentist to determine which it is
  • Rule of thumb: “If the canines are Class I, the incisors should fit together”
  • Also need to look at overjet
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33
Q

What canine class is this?

A
  • Class I Canines
  • Ideal Overjet
  • Max Spacing, Small Laterals
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34
Q

What canine classification is this?

A
  • Class II canines
  • Ideal overjet
  • Laterals width acceptable
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35
Q

What is the most common Bolton discrepancy?

A

Mandibular Excess

  • 2 mm or more will likely rquire Man IPR or Max bonding to finish
  • Alluding to lower picture…Now close spaces to acheive ideal OJ and Class I canines
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36
Q

What is the Gold Standard to determine how teeth will fit together following lower incisor extraction?

A

Kesling Set-up

  • Will need to:
  • Duplicate casts
  • Cut teeth out precisely
  • Set in wax
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37
Q

This picture is exemplifying the…

A

Kesling Set-up

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38
Q

If you have a tooth size discrepancy, treatment decision depends on…

A
  • Canine relationship
  • OJ
  • Intra-arch tooth size relationships
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39
Q

What is the purpose of Serial Extractions?

A

“Robbing Peter to pay Paul”

That is, the purpose of serial extractions is to push the crowding from the anterior region to the posterior region

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40
Q

What are some Criteria for Serial Extractions?

A
  • Mixed dentition stage
  • Severe dental crowding (> 10 mm)
  • Class I skeletal with no other skeletal discrepancies
  • Class I molar with normal OB and OJ
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41
Q

How can a Panorex help you in the mixed dentition state?

A
  • Aids in detection of supernumerary and congenitally missing teeth
  • Detection of pathologic conditions
  • Determination of the size, shape, and relative position of unerupted teeth
  • Assessment of primary root resorption and of permanent root formation
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42
Q

What is the Key to Serial Extractions?

A
  • Key: Extract 1st premolars prior to cuspids erupting
  • Even if performed perfectly, almost all cases require fixed appliances to finalize the occlusion
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43
Q

What type of Class Serial Extraction is this picture showing?

A
  • Extract primary canines (C’s)
  • To allow eruption of the lateral incisors (2’s)
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44
Q

What Classis Serial Extraction Pattern is going on here?

A
  • Extract the primary first molars (D’s)
  • When the permanent first premolars (4s) roots are 1/2 to 2/3 formed
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45
Q

What Classic Serial Extraction Pattern is going on here?

A
  • Extract permanent first premolars (4’s)
  • To allow the permanent canines (3’s)
  • And the second premolars (5’s) to erupt
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46
Q

Is it ok to extract primary molars prior to 1/2 to 2/3rd of root formation of the permanent tooth?

A

No!

  • It delays eruption
  • Promotes loss and thinning of the alveolar crest
  • Can cause impaction, resulting in surgery
47
Q

Is it better to extract symmetrically or asymmetriclly?

A

Symmetrically

This is an error in Serial Extraction

48
Q

If you are missing second premolars, canines, or lateral incisors, is Serial Extraction a good idea?

A

No!

49
Q

What are some problems associated with Serial Extractions?

A
  • Multiple appointments
  • Multiple extractions
  • Patient senses that orthodontic treatment has begun
  • Disappointment when teeth don’t erupt as expected
  • Ultimatley need fixed appliance treatment
50
Q

What is a Posterior Crossbite usually associated with?

A
  • In primary and mixed dentition, generally associated with a bilteral maxillary constriction
  • Ask yourself is it skeletal, dental, unilateral, or bilateral
51
Q

Is this crossbite Skeletal or Dental?

A

Dental

Normal intra-molar width is 36 mm

Approximately the length of a cotton roll

52
Q

Is this Posterior Crossbite Skeletal or Dental?

A

Skeletal

Normal intra-molar width is 36 mm

Approximatley the length of a botton roll

53
Q

Almost all unilateral crossbites are bilateral crossbites with a ______ _______

A

Function Shift

54
Q

What would be required to have a true unilateral crossbite?

A

Asymmetry

55
Q

What are indications for Rapid Maxillary Expansion?

A
  • Bilateral/unilateral posterior crossbites
  • Class II skeletal discrepancies with or without crossbites
  • Cleft lip and/or palate
  • To gain arch length
56
Q

How would you treat Bilateral or Unilateral Crossbites?

A

Rapid Palatal Expansion

Goal: To gain arch length

57
Q

How does a rapid palatal expander work?

A

Correction is a combination of dental tipping and opening of the midpaltal suture

58
Q

Is treating a crossbite easier in the mixed or permanent dentition?

A

Mixed Dentition

59
Q

How do you activate a Rapid Palatal Expander?

A
  • Cemented to the maxillary teeth
  • Activate the screw 1 turn 2 times a day
  • Each turn is 1/4 mm of expansion
  • 1/2 mm per day
60
Q

For Rapid Maxillary Expansion Appliances, is there more expansion at the level of occlusion of the palate?

More expansion anterior or posterior?

A
  • Level of occlusion
  • Anterior
  • Experience little if any discomfort
  • Pressure dissipates in < 15 minutes
61
Q

What is a typical sequelae to the front teeth of Rapid Maxillary Expansion treatment?

A
  • Diastema appears in less than one week
  • Spontaneously relapses closed
62
Q

What is the % breakdown beteen Skeletal and Dental when using a Rapid Maxillary Expansion Appliance?

A

50% Skeletal, 50% dental

More dental tipping as age increases

63
Q

How do you mange Rapid Maxillary Expansion Treatment?

A

Monitoring expansion with occlusal radiographs is generally considered outdated

64
Q

What is the sequale of loosing a mandibular first molar?

A
  • The mandibular first molar is the most common tooth to be missing in the arch
  • The loss of the tooth compromises dental arch integrity
  • Patients delay definitive treatment so opposing teeth supererupt and adjacent teeth rotate and tip into a compromised occlusion
  • Ectopic eruption of 2nd molars
65
Q

What are some conditions that complicate molar uprighting?

A
  • High mandibular plane angle and open bite
  • Periodontal disease
  • Poor crown-to-root ratio and/or short roots
  • Presence of root resorption
66
Q

What is the goal of molar uprighting?

A
  • Facilitate restoration of function by:
  • Allowing occlusal forces to be directed along the long axis of teeth
  • Creating a more favorable crown:root ratio (after reduction)
67
Q

How can molar uprighting affect periodontal prognosis?

A
  • Potentially improve periodontal prognosis by:
  • Eliminating plaque harboring areas
  • Improving alveolar bone profile
68
Q

If the 2nd and 3rd molars are present, should the 3rd molar be extracted or uprighted?

A
  • If insufficient space to upright 3rd molar, then extract
  • Extraction or 3rd molar facilitates uprighting of 2nd molar
69
Q

What type of movement happens to the 2nd molar when molar uprighting?

A
  • Distal crown tipping
  • Vertical effects
  • Increase spce for replacement (pontic, implant)
70
Q

What are the pros of Distal Crown Tipping?

A
  • Fast
  • Creates space for replacement
  • Can improve plaque control and periodontal situation
71
Q

What are the cons of Distal Crown Tipping?

A
  • Will increase height of uprighted molar causing interferences that need to be reduced
  • Might need pre pros endo or intrude after uprighting (will add time)
72
Q

What is an alternative to Molar Uprighting?

A

Mesial Root Movement

73
Q

What are some sequelae of Mesial Root Movement?

A
  • Light forces, slow tooth movement
  • Wide molar root + narrow alveolar ridge = potential dehiscence
  • Maintain or decrease edentulous space
74
Q

What are Pros of Mesial Root Movement?

A
  • Can usually control vertical effects better
  • Will usually maintain or reduce space of missing tooth (sometimes a Con)
75
Q

What is the Con of Mesial Root Movement?

A
  • Takes a LONG time
  • If dont in conjunctino with space closure into long-standing edentulous ridge, could take years
76
Q

What is the goal of Anchorage in Molar Uprighting?

A

Control of unwanted tooth movement

77
Q

What are some ways you can retain the position of the teeth after molar uprighting?

A
  • Can keep pt in braces until provisional is placed
  • Or can make small preparations for intracoronal splint while implant is integrating
78
Q

What facial profile is this?

A

Convex

Glabella - Subnasale - Soft Tissue Pigonion

79
Q

What facial profile is this?

A

Straight

Glabella - Subnasale - Soft Tissue Pogonion

80
Q

What facial profile is this?

A

Concave

Glabella - Subnasale - Soft Tissue Pogonion

81
Q

Why are orthodontists always talking about the cranial base?

A

The cranial base is a stable reference to compare the jaws and teeth to - things that orthodontists can actually change

82
Q

What do Cephalometric Radiographs reveal?

A

Allows us to determine underlying skeletal discrepancies that contribute to the patient’s problem

83
Q

What 4 maxillary positions can contribute to a Class II mal occlusion?

A
  • Maxillary Protrusion
  • Mandibular Deficiency
  • Maxillary Dentoalveolar Protrusion
  • Clockwise rotation of mandible
84
Q

What landmark is this?

A

Sella

Center of hypophyseal fossa

85
Q

What landmark is this?

A

Nasion

Most anterior point of the sagittal junction of the frontonasal suture

86
Q

What is this landmark?

A

Sella-Nasion (S-N)

Cranial Base

87
Q

What is this landmark?

A

Anterior Nasal Spine (ANS)

Most anterior bony point on the maxilla at the base of the nose

88
Q

What is this landmark?

A

A Point

  • Hard Tissue Landmark
  • Innermost curvature of the maxilla between ANS and crest of maxillary alveolar process
  • Usually located just opposite the root tip of the central incisor
89
Q

What is this landmark?

A

Posterior Nasal Spine (PNS)

  • Posterior limit of bony palate
  • Hard Tissue Landmark
90
Q

What plane is this?

A

Palatal Plane

PNS + ANS

91
Q

What is this landmark?

A

B Point

  • Most posterior point on the curvature from bony chin to alveolar junction
  • Anterior limit of mandibular apical base
  • Hard Tissue Landmark
92
Q

What land mark is this?

A

Pogonion (Pog)

  • Most anterior point on the anterior curvature of the mandibular symphysis
  • Hard Tisue Landmark
93
Q

What landmark is this?

A

Menton (Me)

  • Most inferior point on the mandibular symphysis
  • Hard Tissue Landmark
94
Q

What landmark is this?

A

Gnathion (Gn)

  • Most outward and everted point on the curvature of the sympnysis
  • Usually halfway between Pogonion and Menton
  • Hard Tissue Landmark
95
Q

What landmark is this?

A

Gonion (Go)

  • Point at the middle of the curvature at the angle of the mandible
  • Hard Tissue Landmark
96
Q

What landmark is this?

A

Orbitale (Or)

  • The lowest point on the inferior margin of the line bisecting orbits
  • Hard tissue landmark
97
Q

What landmark is this?

A

Porion (Po)

  • Most superior point on the bisected anatomical external auditory meatus
  • Hard Tissue Landmark
98
Q

What landmark is this?

A

Condylion (Co)

  • The most posterosuperior point on the outline of the bisected mandibular condyle
  • Hard Tissue Landmark
99
Q

What angle is this?

A

SNA Angle

  • Measure the angle formed between a N-A (Nasion and A Point) and the SN plane (Sella/Nasion)
100
Q

What angle is this?

A

SNB angle

  • Measure the angle formed between A line Nasion to B point with the SN plane
101
Q

What do SNA and SNB indicate?

A

Indicate the AP position of the maxilla and the mandible relative to the cranial base

102
Q

What do high SNA and SNB values indicate?

A

High values indicate prognathism for that particular jaw

103
Q

What do low SNA and SNB values indicate?

A

Indicate Retrognathism for that particular jaw

104
Q

What can affect SNA and SNB values?

A

Cranial Base Flexure

105
Q

How do you calculate the ANB angle?

A
  • Subtract the previous SNB from SNA measurements
  • A negative value occurs when SNB is greater than SNA
106
Q

What does the ANB angle indicate?

A
  • The ANB angle does not indicate which jaw is at fault
  • It indicates the magnitude of relative A-P jaw discrepancy only
  • It also relates the relative positions of the Max and the MAn to Nasion
107
Q

What is the ANB angle providing you?

A

To help determine the relative relationship of the maxilla to the mandible

108
Q

What is this?

A

Maxillary Incisor

1 to SN (degrees)

  • Angle formed by the long axis of the maxillary central incisor to the SN plane
  • Measures the relative proclination of the maxillary incisor to the cranial base
  • Norm = 103°
109
Q

What is this?

A

Mandibular Incisor

1 to MP (degrees)

  • The angle formed by the intersection of the mandibular plane (Me to line drawn tangent to the angle of the mandible) and a line drawn through the long axis of the mandibular left central incisor
  • Measures proclination of mandibular incisors
  • Norm = 91°
110
Q

What plane is in this picture?

A

Sn to Mandibular Plane

SN - MP

  • Angle between MP and SN
  • Another measure for vertical growth
111
Q

What line is this?

A

E-Line

  • Measurment of lower lip from esthetic line (top of nose to soft tissue pogonion) in millimeters
  • What you really want to know is whether the lips are significantly behind or in front of this line
  • Influenced by large noses and chins
112
Q

What does Mesocephalic mean?

A

Normal

113
Q

What does Brachycephalic mean?

A
  • Deepbite
  • Low angle
  • Short face height
114
Q

What does Dolicocephalic mean?

A
  • High angle
  • Open bite
  • Long face height