orthodontic assessment Flashcards
What steps do we take before coming to a diagnosis
- History
- Extra oral exam
- Intra oral exam
- Special tests
What do we look for when we do our extra oral examination from an ortho point of view
- View patients head from front, side, above and below
- Assess hard and soft tissues in 3 planes
- TMJ
Name the 3 planes we assess the hard and soft tissues in in an extra oral exam
- Antero-posterior
- Vertical
- Transverse
How do we assess the anterior posterior plane
- Assess in natural head position
2. Cab use the kettle method or just visually assess
What is the kettles method
Using your index and pointing finger palpate patients upper and lower jaw and determine if your fingers are portioning straight, upwards or downwards
What does it mean if your fingers are pointing downwards when carrying out kettles method
Class 2 skeletal structure
What does it mean if your fingers are pointing upwards when carrying out kettles method
Class 3 skeletal base
What does it mean if your fingers are pointing straight when carrying out kettles method
Class 1 skeletal base
What is an alternative to the kettle method
The zero meridian line
What is the zeros meridian line also known as
True vertical line
How do we determine where the zero meridian line is
- Get patient to look forward
- Drop an imaginary line vertical from the soft tissue nasian (top of nose)
- Assess the relationship of the lower lip and chin to this line
Describe what you might see in a Class 1 skeletal base in relation to the zero meridian line
- A ‘balanced’ profile
- The upper lip rests on it slightly ahead of the zero meridian line
- Chin lies slightly behind the zero meridian line
- Mandible lies 2-4mm behind the maxilla on palpation
Describe what you would see in an class 2 skeletal base in relation to the zero meridian line
- Mandible appears further behind the maxilla
- Chin lies behind the zero meridian line
- Retrusive mandible
Describe a patient with a class 3 skeletal base in relation to the zero meridian line
- Mandible appears ahead of the maxilla
- Chin lies ahead of the zero meridian line
- The upper lip may be close to or behind the zero meridian line
- Protrusive mandible and/or retrusive maxilla
What do we look for if we suspect a retrusive maxilla
- Paranasal hollowing
- Flat infra-orbital margins
- Flat zygomas (cheekbones)
- In severe cases sclera (white part of eye) may be visible below iris
How do we assess the vertical plane of a patient
- Rule of equal thirds
- Frankfort Mandibular planes angle (FMPA)
- Centrelines
What is the rule of equal thirds
Approx equal thirds between:
- Hairline (trichion) to between the eyebrows (Glabella)
- Glabella to base of nose (subnasale)
- Subnasale to bottom of chin (menton)
What is the upper anterior face height
I he distance between the glabella (between eyebrows) and subnasale (base of nose)
What is the lower anterior face height
Distance between the subnasale (base of nose) and menton (bottom of chin)
How do we assess if the lower anterior face height is normal
Compare it to the upper anterior face height if they are approximately equal then that it average
Where does Frankfort’s plane run
From the bony infra orbital margin to external auditory Meatus
Where does the Mandibular plane run
Along the lower border of the mandible
What is an average Frankfurt Mandibular planes angle
Where they meet at the occiput
What is an increased Frankfurt Mandibular planes angle
Where they meet before the occiput
What is a decreased Frankfurt Mandibular planes angle
Where they meet behind the occiput
How do assess the transverse plane in a patient
- Assess from above below and in front
- Compare between bilateral structure
- Compare to facial Midline
Where may asymmetry be seen?
- Mandible
- Nose
- Maxilla and mandible
- Orbits
Give examples of soft tissues we loom at in our extra oral exam
- Lips
2. Tongue
What do we look at when examining the lips
- Are the competent?
- Length
- Naso-labial angle
- Relationship of lower lip to upper incisors
- Relationship of upper lip to upper incisors
- Smile aesthetics
- Tone / fullness
What is the average value of the Naso-labial angle
90-110 degrees
How much of the upper incisors is seen at rest
3mm on average but reduced with age
What is a lower lip trap
When the lower lip functions behind the upper incisors
In whom is a lower lip trap more common
Patients with class II division 1 malocclusion
Why is a lower lip trap a concern
As the activity of the lower lip proclaimed the upper incisors further increasing the patients overjet
What is a high lower lip line
Where the lower lip covers the upper central incisors and retroclines them
What can a high lower lip line lead to
Class II division 2 malocclusion
What is an adaptive tongue thrust
When the lips are incompetent and the tongue thrusts forward to contact the lips and create an oral seal
What can an adaptive tongue thrust lead to
Reduced overbite/ anterior open bite
How do we classify crowding
Mild medium and severe
How do we define mild crowding
0-4mm crowding
How do we define medium crowding
4-8mm crowding
How do we define severe crowding
More than 8mm crowding
How do we describe incisor relationship
Class I, II, III, IV
Describe a class I incisor relationship
The lower Incisor edges occlude or lie immediately below the cingulum plateau of the upper central incisor
Describe a class II division 1 incisor relationship
The lower incisor edges lie posterior to the cingulum plateau of the upper incisors
Generally incisors are proclined and there is an increased overjet
Describe a class II division 2 incisor relationship
The lower incisor edges lie posterior to the cingulum plateau of the upper informs and upper central incisors are retroclined
Overjet usually minimal
Describe a class III incisor relationship
When the lower incisor edges lie antihero to the cingulum plateau of the upper incisors
What is an overjet
The distance between the lower and upper incisors in the horizontal plane
State a normal overjet
2-4mm
What is a reverse overjet
The lower incisors low anterior to the upper incisors
What is an anterior cross bite
When only 1 or 2 incisors are involved in the occlusion
What is an overbite
The vertical overbite of the upper and lower incisors
What is the upper centreline determined by
The facial midline
What is the lower centreline determined by
The chin point
What is buccal segment relationship looking
The molar teeth
How do we classify buccal segment relationships
Class I, II, III
Describe a class I buccal segment relationship
The media buccal cusp of the upper 6 rests in the lower 6 anterior buccal groove
Describe a class II buccal segment relationship
If the media buccal cusp of the upper 6 rests in front of the anterior buccal groove of the lower 6
Describe a class III buccal segment relationship
The upper and lower 6 don’t occlude
What does canine relationship tell us
Describes the relationship of the top of the upper canine to the embrasure space between the lower canine and first premolar
How do we classify canine relationship
CLASS I, II, III
Describe a class I canine relationship
Direct intercsupatuon of the upper canine and the embrasure between the lower canine and first premolar
Describe a class II canine relationship
When the upper 3 tip is medial the embrasure Space between the lower 3 and 4
Describe a class III canine relationship
When the U3 tip is distal to the embrasure space between the L3 and L4
What is a posterior cross bite
Transverse discrepancy in the buccolingual relationship of the upper and lower teeth
What is a buccal cross bite
When the buccal cusps of the lower teeth occlude buccal to the buccal cusps of the upper teeth
What is a lingual crossbite
When the buccal cusps of the lower teeth occlude lingual to the palatial cusps of the upper teeth
What do you usually find in a patients with a Mandibular crossbite
Mandibular displacement
What is Mandibular displacement
On closure from the rest position there is a premature occlusal contact which causes the mandible to be displaced to the left or right
What special tests can we take to assess orthodontics
- OPT
- Intraoral radiographs
- Lateral cephalogram
- Cone beam CT
Why might we take an OPT to assess orthodontic need
- Screening for pathology
- Assessment of root form and length
- Assessment of bone levels
- Confirming the presence, position and morphology of unerupted teeth
Why might we take a Lateral cephalogram to assess orthodontic need
- Assess skeletal relationship and incisor position
- Aid treatment planning
- Monitor treatment progress
- Monitor growth
Why might we take a cone beam CT to assess orthodontic need
- More accurate localisation and assessment of unerupted teeth
- More accurate assessment of pathology
- TMJ
- Airway analysis
After carrying out your investigations what do you want to come to
An index of orthodontic treatment needs
What does the index of orthodontic need aim to do
Rank malocclusion in terms of the significance of various occlusal traits for a person dental health and perceived aesthetic impairment
What are the two parts that make up the index of orthodontic need
- Dental health
2. Aesthetic component
What does the dental health component of the index of orthodontic need sun to do
Categorise occlusal traits that could have a detrimental effect on the dentition and supporting structure
How is the dental health component of the IOTN categorised
Five grades ranging from 1 (small deviations) to 5(severe malocclusion)
15 letters also assigned to Indicate specific occlusal abnormalities
What does the mnemonic MOCDO stand for
Missing teeth Overjet Crossbite Displacement Overbite
Why do we use the mnemonic MOCDO
If a patient has more than one malocclusion problem this mnemonic helps us prioritise which is the most detrimental
What does the aesthetic component of the IOTN consist of
10 photographs showing different levels of dental attractiveness
1-10