Ortho - ABGD Flashcards
Maxillary Incisor liability
7mm
Mand incisor liability
6mm
Transient mandibular crowding-mm
0-2.0mm
Where does the space come from the incisor liability?
- Interdental spacing in primary dentition
- Increased intercanine width (2 mm)
- Slight labial positioning of the incisors (1-2 mm)
- Distal shift of the canines as the primary first molars are lost (mand/1 mm)
Leeway space- measurments
Max: 1.5mm/quad, 3mm per arch
Mand: 2.5mm/ qud, 5mm per arch
What is E space?
the leeway space with the greatest space gained for the perm dentition
Describe Angle’s Class I
max 1st molar MB cusp occludes with the B groove of Mand molar
Describe Angle’s Class I malocclusion
The 1st molar relation is normal, but the line of occlusion is off (crowding or irregularity)
Normal occlusion- how should the teeth be aligned
The upper and lower teeth should be arranged on a smoothly curving “line of occlusion”
Describe Angle’s Class II
The mandibular 1st molar is distal to the maxillary 1st molar (line of occlusion not specified)
Describe Class II Div I
Protruding max incisors
Could be associated with:
- Underdeveloped lower jaw
- Protrusive upper jaw
- Narrow arch form
Describe Class II Div II
Retruded or bunched maxillary incisors
Could be associated with:
- Underdeveloped lower jaw
- Deep bite
- Laterals and canines tend to be in labioversion while the centrals are upright
How does classification change if the classification varies.
subdivide and indicate side. Class I always comes first
ie: “class I, Class II div 1 subdivision Right
Describe angle class III
The mandibular 1st molar is mesial to the maxillary 1st molar (line of occlusion not specified)
What are other angle classification system- dental short comings?
Crossbite
Depth of bite
Crowding
complexity or severity
What primary occlusion is most common?
mesial step- 61.1%
What do mesial steps often develop into?
If 1mm of mesial shift:
Class I- 68%
Class II- 22.8%
Class III - 1%
If 2mm of mesial shift
Class I: 68%
Class II: 12%
Class III: 19%
What do distal steps develop into?
class II 100%
What do flush terminal planes develop into?
56% Class I
but they are not stable and can easily turn into Class II if there is early tooth loss, ectopic eruption, or caries.
(29% are FTP)
What is interceptive ortho?
INTERVENE IF THERE IS POTENTIAL TO AFFECT GROWTH AND DEVELOPMENT
What problems may need interceptive ortho?
Eruption problems
anter open bite
crossbites
space maint
habits
What % of ectopic eruptions self correct?
60%
How could you correct ectopiceruption of a 1M?
spacer- ~6 weeks. use a radiopaque one!
What teeth are most likely to ectopically erupt
MAX 1M
MAX Incisors
MAX Canines
What are ways to perform a space analysis?
compare space available to space required using:
xrays- CBCT or PAX
proportionality tables and equations
Combo
What is one proportionality equation?
Tanaka- Johnston
What is the Tanaka-Johnston Equation?
1/2(width of the lower 4 incisors) +
MAX: 11 per quad
MAND: 10.5 per quad
THIS IS SPACE NEEDED
What is the name for Tooth size discrepancy
Bolton discrepancy
What is the % size difference between max and mand inciors?
77% (mand are smaller)
How is bolton discrepancies expressed?
in mm- excess or deficiency
ie: You may have maxillary excess or mandibular deficiency to reach a similar outcome
For porportional dentition if the canines are class I, then
then the incisors should fit together (also need to look at overjet and bite)
What might look like a Maxillary Deficiency?
Class I canines
Ideal overjet
Max spacing, small laterals
What might look like a Mandibular Excess?
Class II canines
Ideal overjet
Laterals width acceptable
How to tx a bolton descrepancy?
IPR
Bonding/restorations
Extractions
When would you likely need to do IPR or max bonding?
with mand excess of 2mm or more
if you planned to extract a tooth for space, what is the gold standard for eval/setup?
Kesling Set up which is teeth moved in wax
What four things do you need to consider with treating tooth size discrepancy?
OJ, OB, canine relationship, and INTRA arch size relationship
When would it be appropriate to consider serial extractions?
severe crowding >10mm
mixed dentition
class I skeletal without other skeletal abnormalities
class I molar w normal OJ and OB
What is key to serial extractions?
Extract 1st premolars prior to cuspids erupting.
almost ALWAYS need to finalize with ortho
What is the serial eruption pattern?
Extract C’s to allow 2’s to erupt
Extract D’s when 4’s are 1/2-2/3 form
Extract 4’s to allow 3’s and 5’s to erupt
Full appliance therapy is initiated to align, close spaces, and upright roots
Common errors with serial extraction are?
-ext of primary molar prior to the root formation of the perm tooth being 1/2 to 2/3 complete
-not ext symmetrically
-not having good records
Normal maxillary width of the intra molar @ gingiva
36mm ~cotton roll
Unilateral cross bite? how can you tell?
uni if asymmetry
Bilateral if functional shift
what could a posterior crossbite be caused by?
canine interference- check first contact and adjust if needed
Correction by expansion indications? What is it?
-Bilateral/unilateral posterior crossbites
-Cleft lip/palate
-To gain arch length
Tx: A combination of dental tipping and opening of the midpalatalsuture
For a rapid palate expander, does it stay open?
no, it spontaneously closes shut
What is the ratio of dental to skeletal changes with palate expansion
~50/50. increases dental changes as the pt ages
What parts open more with expansion?
ANt and Occlusal
What are 6 types of palate expansion?
Haas, Bonded, Fan, Hyrax, removable, quad helix or W arch(less force)
When and what happens when using a quad helix or W arch
Slow expansion
use in Early mixed dentition
Mostly dentoalveolar changes
Some orthopedic effect in young children
Molar control
De-rotation
What is a MARPE
MARPE
Mini-screw Assisted Rapid Palatal Expander
Abbreviation and where: Stella
S - Center of the hypophyseal fossa
Abbreviation and where: Nasion
N
Most anterior point of the sagittal junction of the frontonasal suture
Abbreviation and where: A point
A:
Innermost curvature of the maxilla between ANS and crest of maxillary alveolar process
–Usually located just opposite the root tip of the central incisor
ANS
Anterior Nasal Spine
Most anterior bony point on the maxilla at the base of the nose
PNS?
Posterior Nasal Spine
posterior limit of bony palate
Palatal Plane connects what?
ANS and PNS
B point
B
Most posterior point on the curvature from bony chin to alveolar junction
Anterior limit of mandibular apical base
Whats the order of the chin points?
Superior to Inferior: Pg, Gn, Me
Pogonion?
Pog or Pg
Most anterior point on the anterior curvature of the mand symphysis
Menton?
Me
Most inferior point on the mand symphysis
Gnathion
Gn
Most outward and everted point on the curvature of the symphysis
Half way between Pg and Me
Gonion
Go
Point at the middle of the curvature at the angle of the mandible
Orbitale
Or
the lowest po$int on the inferior margin of the line bisecting orbits
Porion
Po
Most superior point on the bisected anatomical external auditory meatus
Condylion
Co
The most posterior superior point on the outline of the bisected mandibular condyle
What does SNA and SNB indicate?
the position of the maxilla and mandible relative to the cranial base
What doe sa high value of the SNA/SNB mean?
the jaw has prognathism
What kind of value SNA/SNB would a retrognathic jaw have?
lower value
How do you find the ANB?
SNA-SNB = ANB
Determines the relative relationship of the maxilla to the mandible
ANB angle of 0-4 is what class?
class 1
ANB angle of -2-0 is what class?
Class III
ANB angle of >4 is what class?
Class II
What is the normal SNA? SNB?
82, 80
Normal value of the maxillary incisor to the SN plane?
103
measures the relative proclination of the incisor to the cranial base
What the normal value of the mandibular incisor to the mandibular plane?
91 degrees
measures proclination of incisors
What is the Sassouni Analysis?
In a well proportioned face, a series of horizontal planes will project toward a common meeting point
What is the lower lip to E line (in mm)?
determines if the lips are too far in front or behind this esthetic line. Measured from tip of nose to soft tissue Pogonion
what are the three types of face shapes?
Brachycephalic
Dolicocephalic
Mesocephalic
What are two ortho movements theories?
- Pressure- Tension
- Piezoelectric theory
What happens in the first phase of pressure?
Hyalinization.
What is Hyalinization?
Pressure prevents blood flow and cell differentiation
creates a layer of sterile, necrotic zone “hyalinized layer”
What are the 3 components of Hyalinized layer
- Degeneration
- Elimination of destroyed tissue from bone marrow space “undermining resorption”
- Re-establishment
6 Types of tooth movement
- Translation/body movement
- Tipping
- Rotation
- Extrusion
- Intrusion
- Torque
What happens in the secondary period of tooth movement?
after the initial phase where movement stops, there is a period of increased tooth movement. which has reduced deposition of new bone and move efficient tooth movement.
At what grams is forced eruption?
35-60
What is the rate of forced eruption?
no more than 1-2mm/month
Force eruption: How do you calculate extrusion distance?
x(apical margin to alveolar crest + BW(2.04mm), +1mm
crown to root ratio should be >/= 1:1
which means you need at least 3-4mm total eruption above crestal bone
How long do you keep retention on in force eruption?
1 month for ever month that it took… so ~ additional 3-4 months.
What is the orthodontic technique for forced eruption?
-Anchorage from adjacent teeth is usually sufficient
–Need rigidity over the anchor teeth and flexibility where it attaches to the tooth to be extruded
–2 methods -with or without brackets
When do you do a supracrestal fiberotomy?
trauma, subgingival caries, resorption, iatrogenic perforation
DONT do it for implant site development
How do you distal crown tip?
Anchorage, open coil spring, gable bend to counteract the the DL forces
What are the periodontal risks of ortho?
- uncontrolled periodontal disease
- reduction of attached gingiva/recession
-fenestration and dehiscence
root resorption–> both external apical and invasive cervical
What are the types of External apical resorption?
Surface: outer layer, can regen
Deep resorption: cementum and dentin, may not be same shape, even regens a little
Circumferential root resorption: tridimentional resorption at apex, root shortening evident. not repairable
What is the prevalence of EARR? Severe?
> 90%…severe only 1-5%= 4mm or 1/3 root
Risk factors of EARR?
hx of resorption, increased length of tx, genetic predisposition.
MAYBE: asthma, dysostosis, endocrine issues
Management of EARR?
take xrays to monitor progress, stop or pause tx, perio tx.
Invasive Cervical Root Resorption- external or internal?
external.
How to treat ICRR?
proper diagnosis, refer to endo who they might sx exposure endo therapy, remove infected dentin, repair with GI and BECAUSE, then monitor
Which wire type allows for the tipping of crowns?
Round
Which wire type provide torque and root movement?
Rectangular
How many grams are needed to perform intrusion?
10-20 grams
How many grams are needed to perform rotation?
35-60 grams
How many grams are needed to perform tipping?
35-60 grams
How many grams are needed to perform translation?
70-120 grams
How many grams are needed to perform root uprighting?
50-100 grams
What is the arch wire Sequence?
Early Alignment
Later Alignment
Leveling
Space Closure Preparation
Space Closure and Molar Correction
Finishing and Detailing
What wire is used for early alignment?
0.014 or 0.016 NiTi
What wire is used for later alignment?
17x25 or 19x25 NiTi if rotation correction is needed.
0.018 NiTi if only few problems
What wire is used for leveling?
0.018 or 0.020 SS
What wire is used for space closure preparation?
17x25 SS
What wire is used for space closure and molar correction?
18x25 or 19x25 SS
What wire is used for finishing and detailing?
19x25 SS or TMA
What is the benefit of NiTi?
good shape memory and less stiff
What is the benefit of SS
Stiff, can place bends
What is the benefit of TMA (Titanium Molybdenum Alloy)/Beta Titanium
More spring/room for error. can place bends
very expensive!
What is PoG or Pg?
Pogonion (top one)
What is Me?
Menton (bottom one)
What is Gn?
Gnathion - middle one
What is Po?
Porion - most superior part of EAM (ear)
What is Co?
Condylion - superior and back part of condyle
What kind of wires do you need for aligning and level?
Align: Round NiTi
Level: large rectangular wires
What wires would you use for Finishing and Detailing?
Steel or TMA
What cases would you utilize interceptive ortho treatment?
Eruption problems
Anterior open bite
Posterior open bite
Anterior cross bite
Space maintenance
Habits (thumb sucking
Describe the following facial types:
Brachycephalic
Brachycephalic:
-short, square facial type
-low mandibular plane angle
-decreased anterior vertical height
-often presents with anterior deep bite
Describe the following facial types: Dolicocephalic,
Dolicocephalic:
-long, narrow facial type
-high mandibular plane angle
-increased anterior vertical height
-sometimes presents with an anterior open bite
Describe the following facial type:
Mesocephalic
-average facial proportions
What are indications for forced eruption of a tooth?
to obtain access for endodontic and restorative procedures
-to reduce pocket depth
-when extensive crown lengthening would be unaesthetic or produce poor C:R ratio
-to improve site for implant
-impaction or delayed eruption
What are some of the periodontal risks associated
with orthodontic treatments?
-uncontrolled perio disease
-root resorption: external apical or invasive cervical
-reduction of the attached gingiva/recession
-fenestrations and dehiscences
How much force (in grams) should you extrude a tooth and at what rate?
Force level: 35-60grams
Rate of extrusion: no more than 1-2mm/month
You have a 4 year old patient who lives in an area where the fluoride in the drinking water is between 0.3-0.6ppm. Should you provide Fl supplement…if so, how much?
Yes, 0.25mg per day
What are some treatment options for correction of a posterior cross bite in a growing child?
Rapid palatal expansion for bilateral or unilateral
Mixed dentition > permanent
Cleft lip
Gains arch length
Basically dental tipping as you use on older patients
Opens up mid-palatal suture
Ex: HAAS, Hyrax,
MARPE (mini-screw assisted RPE): screws are in palate, crank open, needs CBCT
SARPE (surgery assisted RPE)
Describe appropriate orthodontic forces
Bodily Movement: 70-120g
Uprighting: 50-100g
Rotating/extrusion/tipping: 35-60g
Intrusion: 10-20g
Does ortho treatment cause
root resorption? Why?
Yes
Etiology is not fully understood but it appears
to be an effect of mechanical stimulation,
pressure on the PDL, activates osteoclasts.
90% of ortho treated teeth exhibit some, 1-5%
are severe. Key is to utilize lighter, sustained
forces. Most common are incisors.
Pre-disposing factors: Hx of resorption,
trauma, extended ortho treatment
What is Steiner’s Analysis?
Key Points..
First modern analysis. Relates
A/P position of maxilla and
mandible to cranial base.
SNA, SNB, ANB
ANB ≅2°
If >2 then Class 2
If < 2 then Class 3
What is Tweed’s Analysis?
Key Elements
Simple, clinically useful analysis that used a triangle
to establish ceph norms, identifies tendencies
FMS: frankfurt mand angle, normal 25* 30+=high FMA
FMIA: Frankfurt mand inxisal Angle
IMPA: incisal mand plane angle
Frankfurt plane = Porior and orbitale
What is Wit’s Appraisal?
Compares the A/P position of the maxilla and mandible to the occlusal plane, measured in MM
What is Stephan’s curve?
Describes the change in pH that occurs
following a cariogenic challenge
Critical pH of enamel = 5.5
Point at which enamel demineralizes
Cementum: 6.0-6.7
Molar Uprighting- why?
-allow occlusal forces to be directed along long axis of the tooth
-create a more favorable C:R ratio (after occlusal adjustment) increase space for pontic/replacement
-will increase height of uprighted molar: interferences need to be reduced *endo or intrusion
Potentially improve perio diagnosis:
-eliminate plaque harboring areas
-improve alveolar bone profile
What are the basics for clear aligners? how long you wear, how muhc movement?
-worn 22 hours/day
-movement: 0.25mm/aligner; 0.1mm for finishing
(may involve IPR)
Wht are the indications of clear aligners?
ndications:
-Class I, mild malocclusion
-Can move teeth 1-5mm in permanent teeth
-patients who previously had ortho, stopped
wearing retainers
What are the contraindications for clear aligners?
Contraindications:
-skeletal changes >2mm, crowding >2mm, open
bites, short clinical crowns, severely tipped or
rotated (>20°), difficult for canines, multiple missing
teeth, molar translations that would require TAD,
extrusion of impacted teeth, poor patient
compliance, TAD, patients still growing
When should thumb sucking
be addressed?
ASAP
- >3 years: damage will be long-lasting and
detrimental to success
- >4 years: finger habit can be well established
and much harder to stop
What is this and what it is used for?
Modified bluegrass and thumbsucking
What is this?
W ARCH
What is this?
Quad Helix
What is this?
Haas
WHAT IS THIS
Hydrax
What cephalometric points
can be used to analyze facial
profile?
Glabella
Subnasale
Soft Tissue Pogonion
