Orthodontics - ABGD Oral Boards Flashcards
(114 cards)
1
Q
Where are the primate spaces?
A
- Maxillary Primate Space distal to laterals
- Mandibular Primate Space distal to canines
2
Q
How many mm is Incisor Liability in primary dentition in the maxilla?
A
7.0 mm
3
Q
How many mm is Incisor Liability in primary dentition in the mandible?
A
6.0 mm
4
Q
How man mm is Transient Mandibular Crowding?
A
0 - 2.0 mm
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)
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
7
Q
What accounts for the “E” space?
A
Most of the space is due to the size difference in the second primary molars
8
Q
What are the 3 Primary Second Molar relationships?
A
9
Q
What are 3 factors that influence the first permanent mlar relationship?
A
- Early mesial shift
- Late mesial shift
- Differential growth
10
Q
What types of occlusion will primary distal step, flush terminal plane, and mesial step typically transition into in the permanent dentition?
A
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
12
Q
What Molar Class is this?
A
Class I Molar
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
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
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)
16
Q
What type of occlusion is this?
A
Class III
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
18
Q
What’s the difference between Class 2 Div I and Class 2 Div II?
A
19
Q
What type of occlusion is this?
A
Class II Div I
20
Q
What type of occlusion is this?
A
Class II Div 2
21
Q
Which teeth most commonly show Ectopic Eruption?
A
- Maxillary First Permanent Molars
- Incisor
- Canines
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
23
Q
What is going on here?
A
Ectopic Eruption
24
Q
How can you treat Ectopic Eruption?
A
Separators
25
Describe the Radiographic Method of Space Analysis...
* 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
26
What are some space analysis names that have Proportionality Formulas?
Tanak and Johnston
27
Describe the Tanaka-Johnson Formula...
* No radiographs
* Predicts both arches
* Reasonably good correlation
* Data obatined from Caucasion population, may not be approppriate for all ethnicities
28
What is a Combination medthod of Space Required Analysis?
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
29
What are 3 key recommendations for Mixed Dentition Space Analysis?
* 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
30
What is the Bolton Tooth Size Analysis?
Evaluation of the mesial/distal tooth size discrepancies between maxillary and mandibular arches
31
What is the formula for the Bolton Space Analysis?
32
Describe the Interpretatin of the Bolton Space Analysis...
* 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
33
What canine class is this?
* Class I Canines
* Ideal Overjet
* Max Spacing, Small Laterals
34
What canine classification is this?
* Class II canines
* Ideal overjet
* Laterals width acceptable
35
What is the most common Bolton discrepancy?
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
36
What is the Gold Standard to determine how teeth will fit together following lower incisor extraction?
Kesling Set-up
* Will need to:
* Duplicate casts
* Cut teeth out precisely
* Set in wax
37
This picture is exemplifying the...
Kesling Set-up
38
If you have a tooth size discrepancy, treatment decision depends on...
* Canine relationship
* OJ
* Intra-arch tooth size relationships
39
What is the purpose of Serial Extractions?
"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
40
What are some Criteria for Serial Extractions?
* Mixed dentition stage
* _Severe dental crowding (\> 10 mm)_
* Class I skeletal with no other skeletal discrepancies
* Class I molar with normal OB and OJ
41
How can a Panorex help you in the mixed dentition state?
* 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
42
What is the Key to Serial Extractions?
* Key: Extract 1st premolars prior to cuspids erupting
* Even if performed perfectly, almost all cases require fixed appliances to finalize the occlusion
43
What type of Class Serial Extraction is this picture showing?
* Extract primary canines (C's)
* To allow eruption of the lateral incisors (2's)
44
What Classis Serial Extraction Pattern is going on here?
* Extract the primary first molars (D's)
* When the permanent first premolars (4s) roots are 1/2 to 2/3 formed
45
What Classic Serial Extraction Pattern is going on here?
* Extract permanent first premolars (4's)
* To allow the permanent canines (3's)
* And the second premolars (5's) to erupt
46
Is it ok to extract primary molars prior to 1/2 to 2/3rd of root formation of the permanent tooth?
No!
* It delays eruption
* Promotes loss and thinning of the alveolar crest
* Can cause impaction, resulting in surgery
47
Is it better to extract symmetrically or asymmetriclly?
Symmetrically
This is an error in Serial Extraction
48
If you are missing second premolars, canines, or lateral incisors, is Serial Extraction a good idea?
No!
49
What are some problems associated with Serial Extractions?
* 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
What is a Posterior Crossbite usually associated with?
* In primary and mixed dentition, generally associated with a bilteral maxillary constriction
* Ask yourself is it skeletal, dental, unilateral, or bilateral
51
Is this crossbite Skeletal or Dental?
Dental
Normal intra-molar width is 36 mm
Approximately the length of a cotton roll
52
Is this Posterior Crossbite Skeletal or Dental?
Skeletal
Normal intra-molar width is 36 mm
Approximatley the length of a botton roll
53
Almost all unilateral crossbites are bilateral crossbites with a ______ \_\_\_\_\_\_\_
Function Shift
54
What would be required to have a true unilateral crossbite?
Asymmetry
55
What are indications for Rapid Maxillary Expansion?
* Bilateral/unilateral posterior crossbites
* Class II skeletal discrepancies with or without crossbites
* Cleft lip and/or palate
* To gain arch length
56
How would you treat Bilateral or Unilateral Crossbites?
Rapid Palatal Expansion
Goal: To gain arch length
57
How does a rapid palatal expander work?
Correction is a combination of dental tipping and opening of the midpaltal suture
58
Is treating a crossbite easier in the mixed or permanent dentition?
Mixed Dentition
59
How do you activate a Rapid Palatal Expander?
* 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
For Rapid Maxillary Expansion Appliances, is there more expansion at the level of occlusion of the palate?
More expansion anterior or posterior?
* Level of occlusion
* Anterior
* Experience little if any discomfort
* Pressure dissipates in \< 15 minutes
61
What is a typical sequelae to the front teeth of Rapid Maxillary Expansion treatment?
* Diastema appears in less than one week
* Spontaneously relapses closed
62
What is the % breakdown beteen Skeletal and Dental when using a Rapid Maxillary Expansion Appliance?
50% Skeletal, 50% dental
More dental tipping as age increases
63
How do you mange Rapid Maxillary Expansion Treatment?
Monitoring expansion with occlusal radiographs is generally considered outdated
64
What is the sequale of loosing a mandibular first molar?
* 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
What are some conditions that complicate molar uprighting?
* High mandibular plane angle and open bite
* Periodontal disease
* Poor crown-to-root ratio and/or short roots
* Presence of root resorption
66
What is the goal of molar uprighting?
* 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
How can molar uprighting affect periodontal prognosis?
* Potentially improve periodontal prognosis by:
* Eliminating plaque harboring areas
* Improving alveolar bone profile
68
If the 2nd and 3rd molars are present, should the 3rd molar be extracted or uprighted?
* If insufficient space to upright 3rd molar, then extract
* Extraction or 3rd molar facilitates uprighting of 2nd molar
69
What type of movement happens to the 2nd molar when molar uprighting?
* Distal crown tipping
* Vertical effects
* Increase spce for replacement (pontic, implant)
70
What are the pros of Distal Crown Tipping?
* Fast
* Creates space for replacement
* Can improve plaque control and periodontal situation
71
What are the cons of Distal Crown Tipping?
* 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
What is an alternative to Molar Uprighting?
Mesial Root Movement
73
What are some sequelae of Mesial Root Movement?
* Light forces, slow tooth movement
* Wide molar root + narrow alveolar ridge = potential dehiscence
* Maintain or decrease edentulous space
74
What are Pros of Mesial Root Movement?
* Can usually control vertical effects better
* Will usually maintain or reduce space of missing tooth (sometimes a Con)
75
What is the Con of Mesial Root Movement?
* Takes a LONG time
* If dont in conjunctino with space closure into long-standing edentulous ridge, could take years
76
What is the goal of Anchorage in Molar Uprighting?
Control of unwanted tooth movement
77
What are some ways you can retain the position of the teeth after molar uprighting?
* Can keep pt in braces until provisional is placed
* Or can make small preparations for intracoronal splint while implant is integrating
78
What facial profile is this?
Convex
Glabella - Subnasale - Soft Tissue Pigonion
79
What facial profile is this?
Straight
Glabella - Subnasale - Soft Tissue Pogonion
80
What facial profile is this?
Concave
Glabella - Subnasale - Soft Tissue Pogonion
81
Why are orthodontists always talking about the cranial base?
The cranial base is a stable reference to compare the jaws and teeth to - things that orthodontists can actually change
82
What do Cephalometric Radiographs reveal?
Allows us to determine underlying skeletal discrepancies that contribute to the patient's problem
83
What 4 maxillary positions can contribute to a Class II mal occlusion?
* Maxillary Protrusion
* Mandibular Deficiency
* Maxillary Dentoalveolar Protrusion
* Clockwise rotation of mandible
84
What landmark is this?
Sella
Center of hypophyseal fossa
85
What landmark is this?
Nasion
Most anterior point of the sagittal junction of the frontonasal suture
86
What is this landmark?
Sella-Nasion (S-N)
Cranial Base
87
What is this landmark?
Anterior Nasal Spine (ANS)
Most anterior bony point on the maxilla at the base of the nose
88
What is this landmark?
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
What is this landmark?
Posterior Nasal Spine (PNS)
* Posterior limit of bony palate
* Hard Tissue Landmark
90
What plane is this?
Palatal Plane
PNS + ANS
91
What is this landmark?
B Point
* Most posterior point on the curvature from bony chin to alveolar junction
* Anterior limit of mandibular apical base
* Hard Tissue Landmark
92
What land mark is this?
Pogonion (Pog)
* Most anterior point on the anterior curvature of the mandibular symphysis
* Hard Tisue Landmark
93
What landmark is this?
Menton (Me)
* Most inferior point on the mandibular symphysis
* Hard Tissue Landmark
94
What landmark is this?
Gnathion (Gn)
* Most outward and everted point on the curvature of the sympnysis
* _Usually halfway between Pogonion and Menton_
* Hard Tissue Landmark
95
What landmark is this?
Gonion (Go)
* Point at the middle of the curvature at the angle of the mandible
* Hard Tissue Landmark
96
What landmark is this?
Orbitale (Or)
* The lowest point on the inferior margin of the line bisecting orbits
* Hard tissue landmark
97
What landmark is this?
Porion (Po)
* Most superior point on the bisected anatomical external auditory meatus
* Hard Tissue Landmark
98
What landmark is this?
Condylion (Co)
* The most posterosuperior point on the outline of the bisected mandibular condyle
* Hard Tissue Landmark
99
What angle is this?
SNA Angle
* Measure the angle formed between a N-A (Nasion and A Point) and the SN plane (Sella/Nasion)
100
What angle is this?
SNB angle
* Measure the angle formed between A line Nasion to B point with the SN plane
101
What do SNA and SNB indicate?
Indicate the AP position of the maxilla and the mandible relative to the cranial base
102
What do high SNA and SNB values indicate?
High values indicate prognathism for that particular jaw
103
What do low SNA and SNB values indicate?
Indicate Retrognathism for that particular jaw
104
What can affect SNA and SNB values?
Cranial Base Flexure
105
How do you calculate the ANB angle?
* Subtract the previous SNB from SNA measurements
* A negative value occurs when SNB is greater than SNA
106
What does the ANB angle indicate?
* 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
What is the ANB angle providing you?
To help determine the relative relationship of the maxilla to the mandible
108
What is this?
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
What is this?
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
What plane is in this picture?
Sn to Mandibular Plane
SN - MP
* Angle between MP and SN
* Another measure for vertical growth
111
What line is this?
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
What does Mesocephalic mean?
Normal
113
What does Brachycephalic mean?
* Deepbite
* Low angle
* Short face height
114
What does Dolicocephalic mean?
* High angle
* Open bite
* Long face height
