10. Orthodontics Flashcards
What are the 4 components of an orthodontic assessment?
- History
- E/O assessment
- I/O assessment
- Orthodontic assessment
What is included in the E/O component of an Ortho assessment?
Skeletal Pattern
TMJ
Lip line
What is included in the I/O component of an Ortho assessment?
Tooth chart
Periodontal asssessment
Plaque index
What is included in the orthodontic component of an Ortho assessment?
Tooth inclination
Tooth alignment
Mixed dentition analysis
Tooth relationships
Bite analysis
Centreline assessment
What are the 3 areas assessed in a skeletal pattern asssesment?
Anteroposterior
Vertical
Transverse
How is anteroposterior skeletal pattern measured?
Two finger method
How is vertical skeletal pattern measured?
Using FMPA and LFH
How is transverse skeletal pattern measured?
Assesses symmetry by splitting face into 5ths
What is assessed in a lip assessment?
Lip competency and smile line
What are the two components of an intraoral exam in Ortho?
Gingival assessment: general condition, BPE, plaque index
Dental assessment: dental chart, any additional findings, caries risk assessment
What are the 4 components of the Ortho stage of assessment?
Tooth inclination
Tooth alignment
Mixed dentition analysis
Occlusal assessment
Tooth inclinations:
Average
Proclined
Reteroclined
Tooth alignments:
Aligned
Crowded
Spaced
What is the mixed dentition analysis?
A measurement if enough space for teeth to erupt
Done by: measuring from distal of 2 to medial of 6
21mm = average for lower arch
22mm = average for upper arch
List the 8 things assessed in an orthodontic occlusal assessment:
Incisor, canine and molar relationships
Overjet
Overbite
Open bite
Cross bite
Centrelines
What radiogrpah is commonly used in orthodontics?
Lateral cephalograms
What is the 4 steps process in manually processing a lateral ceph?
- Draw outlines
- Locate points
- Join dots
- Measure angles
What points are plotted on a lateral ceph?
Sella
Nation
ANS
PNS
A Point
B point
Gonion
Menton
What dots are joined on a ceph?
S and N (cranial base)
N and A
N and B
Ans and pns (maxilla)
Gonion and menton (mandible)
Upper incisors
Lower incisors
What 6 angles are measured on a ceph?
SNA, SNB, ANB, MMPA, INCISOR, E PLANE
SNA angle
Indicates maxilla in relation to cranial base
> 82 degrees = prognathic
< 82 degrees = reterognathic
SNB angle
Indicates mandible in relation to cranial base
> 80 degrees= prognathic
< 80 degrees = reteroganthic
ANB angle
Indicates maxilla in relation to mandible
> 4 degrees = class II skeletal pattern
< 2 degrees = class III skeletal pattern
MMPA angle
Intersection of maxilla and mandible
Increased angle = vertical growth
Decreased angle = horizontal growth
Incisor inclination angle
110 = maxillary average
90 = Mandibular average
Increased angle = proclined
Decreased angle = reteroclined
E plane angle
Line drawn from nose tip to chin
Should be a distance of:
1-2mm from lower lips
2-3mm from upper lips
what does IOTN stand for and what are the 2 components of it?
Index of orthodontic treatment need
Dental component
Aesthetics component
How is the dental health component calculated?
MOCDO and IOTN ruler
Grade 1 = no Tx needed
Grade 5 = very great need for Tx
What does MOCDO stand for?
Missing
Overjet
Crossbites
Displacement
Overbite
What is the aesthetic component of the IOTN?
A 10 point photo scale
What are the 4 main roles of the GDP in relation to orthodontics?
Identify, examine and refer using IOTN
maintain OH
Orthodontic first aid
Retain Tx outcomes
What 9 things should be included in an Ortho referral letter?
- Urgency level
- Pt details
- Reason for referral
- History (HPC, MH, SH, DH)
- Previous Tx history
- Summary of malocclusion
- IOTN grade
- Radiographs
- Study models
How is A-P skeletal pattern assessed and what are the grades?
2 point finger test
Class I - hand level - maxilla and mandible orthognathic/straight
Class II - hand tilts up - maxilla forward and mandible back
Class III - hand tilts down - maxilla back and mandible forward
How is VERTICAL skeletal pattern assessed?
FMPA and LFH
FMPA:
average - intersects at occiput
increased - intersects at ear
decreased - intersects beyond head
LFH:
face split into 1/3’s
- average/increased/ decreased
How is TRASVERSE skeletal pattern asssed?
Assesses facial symmetry
Done by splitting face into vertical fifths
CLASS I MOLAR RELATIONSHIP
MB cusp of U6, sits in buccal groove of L6
CLASS II MOLAR RELATIONSHIP
MB cusp of U6, sits anterior to buccal groove of L6
CLASS III MOLAR RELATIONSHIP:
MB cusp of U6, sits posterior to buccal groove of L6
CLASS I CANINE RELATIONSHIP
L3 sits mesial to U3
CLASS II CANINE REALTIONSHIP
L3 Sits distal to U3
CLASS III CANINE RELATIONSHIP
L3 and U3 do not occlude
Overjet
Horizontal overlap of teeth
Overbite
Vertical overlap of teeth
Openbite
No overlap of teeth
Cross bite
Unilateral or bilateral
Buccal or lingual
Always relates to buccal cusps of lower teeth
What are the 3 types of orthodontic appliance?
Removable
Fixed
Functional
What are the 4 components of a removable appliance?
- Active (springs, biteplabes, screws, bows)
- Retentive (clasps)
- Anchorage
- Baseplate (connector of all components)
What is a fixed appliance?
An appliance made up of brackets attached to teeth and and arch wire
What 3 planes do fixed appliances move teeth?
Tipping
Body movements
Torque
What 2 materials are used for fixed applaince wires?
Nickel titanium NiTi
Stainless steel SS
What is a functional appliance?
A group of appliances used only in the growing patient that aims to redirect masticatory forces and muscles to create tooth movement and modify facial growth
What are the indications for functional appliances?
Mild/moderate skeletal discrepancies
Overjet/overbites
Pre adolescent growth
List 3 common problems associated with tooth eruption and occlusion:
Eruption cysts
Impacted teeth
Crossbites
Signs of an eruption cyst:
Blue mucosa overlying an unerupted tooth
List 4 causes of impacted teeth:
Obstructions
Eruption failure
Insufficient space
Ectopic teeth
What teeth are commonly affected by Crossbites?
Molars and incisors
What causes infra-occluded deciduous teeth?
Ankylosis of deciduous teeth
No permanent successor
What causes deciduous teeth to be retained?
Missing permanent successors
Ankylosis
What 4 teeth are commonly affected by impaction?
E’s
6’s
Centrals
Canines
How should impacted E’s be managed?
Place separator or Xla
How should impacted 6’s be managed?
Separator or XLA
What causes impacted central’s?
Supernumaries
Crown-root dilaceration
Trauma
Premature loss of decidious teeth
How should impacted centrals be managed?
Remove obstruction
Expose
URA to align
How should impacted canines be managed?
Should be palpable aged 8-10 and radiographed
If impacted,
Extract C’s and wait for eruption
If this fails,
Treat in permeant dentition phase by exposing/extracting/ monitoring
