Orthodontic Assessment Flashcards
when do we carry out orthodontic assessment? (4)
Ages 9: brief examination
11-12: Comprehensive examination when canines are premolars erupt
When older patients first come to you (if never been before)
If malocclusion develops in later life
what is an ideal occlusion based on?
Andrews 6 keys
list Andrew’s 6’s keys
Molar relationship Crown angulation Crown inclination No rotations No spaces Flat occlusal planes
teeth must all be the correct size
define the ideal molar relationship in relation to Andrew’s 6 keys.
The distal surface of the distobuccal cusp on the upper 1st permanent molar occludes with the medial surface of the mesiobuccal cusp if the lower 2nd molar.
define malocclusion.
More significant deviations from the ideal occlusion. May be considered as unsatisfactory aesthetically or functionally.
what are contraindicators to orthodontic treatment?
Allergy to Ni or latex
Epilepsy and the drugs used to control it
Some medications
Problems with imaging i.e. radiographs
when carrying out an orthodontic assessment what is important to note from their past dental history?
Frequency of attendance
Nature of previous treatment
Co-operation of previous treatment
Trauma to the dentition
when carrying out an orthodontic assessment what is important to note from their social history?
Habits: Thumb sucking Lower lip sucking Tongue thrust Chewing nails (can cause root resorption)
when carrying out an extra-oral examination which head position should the patient be in?
looking straight ahead with their frankfort plan parallel to the floor.
what should be examined in an extra-oral examination during orthodontic assessment?
Skeletal bases
Soft tissues
TMJ
what is it important to compare the patient to when carrying out an orthodontic assessment?
Compare the patient to their parent (especially class III)
look for Malocclusion
Growth potential
what 3 skeletal planes do we examine in a patient?
Antero-postero
Vertical
Transverse
how do we position the patient when examine the skeletal relationship? (3)
Patient can either be standing or seated
Ensure the Frankfort plane is horizontal to the floor = the superior border of the EAM to the lower border of the orbit
Or get the patient to look into their own eyes in the mirror which is a distance away
define a class I antero-postero skeletal pattern.
Maxilla 2-3mm in front of the mandible
define a class II antero-postero skeletal pattern.
Maxilla is > 3mm in front of the mandible)
These patients are retronathic: DONT have a small mandible it’s just further back on the skeletal base
define a class III antero-postero skeletal pattern.
Mandible is in front of the maxilla (maxilla is less than 2-3mm infront)
how do we assess the vertical skeletal pattern clinically ? (2)
We use the FMPA
- normal angle is 27 +/- 4
LAFH:TAFH - lower anterior face height to total AFH ratio
describe how the line from the frankfort plane and the mandibular plane interact in normal vertical skeletal patterns.
converge at the back of the head
normal angle is 27 +/- 4 degrees
describe how the line from the frankfort plane and the mandibular plane interact in increased vertical skeletal patterns.
lines meet way before the back of the head around the ear - Patient will have an AOB
long face angle is 31 degrees
describe how the line from the frankfort plane and the mandibular plane interact in decreased vertical skeletal patterns.
lines don’t converge at the back of the head - patient will have a deep bite
short face angle is = < 23
what does the lateral skeletal pattern assess?
asymmetry
what reference line do we use to assess asymmetry in the lateral skeletal pattern?
We use the mid sagittal reference line: draw a line down the inter-pupillary line (between the pupils) and down the cupids bow and chin.
what are competent lips?
Competent: Lips meet at rest when the mentalis muscle is relaxed
what are incompetent lips?
Incompetent: Lips do not meet at rest when the mentalis muscle is relaxed
what impact does a lip trap have on orthodontic treatment?
Lip trap: may proline the upper incisors and lead to a relapse of the overjet if the LT persists after treatment.
describe how lower lip activity leads to relapse after orthodontic treatment?
hyperactive/tight lower lips can lead to retroclined lower incisors and instability/relapse after treatment
what malocclusion is tongue thrust associated with?
AOB
name the 2 types of tongue thrust.
endogenous or adaptive i.e. have they got an AOB because they have a tongue thrust or is the tongue thrust there because they have an AOB (adaptive)
what type of tongue thrusts can result in a relapsed AOB?
ENDOGENOUS
What are he dental implications of digit sucking?
Proclined upper incisors
Retroclined lower incisors
Localised anterior open bite or incomplete open bite
Narrow upper arch +/- a unilateral posterior cross bite
Why do patients who suck their thumb develop a posterior crossbite?
The mandible drops due to the position of the digits and the tongue is held lower
The cheeks moving in and out from the sucking narrows upper buccal segments.
The upper jaw is now the same width as the lower jaw
The patient unconsciously decides to bite down on one side to get maximum intercuspation.
what should you examine in terms of the TMJ for an orthodontic assessment? (6)
Path of closure Range of movement Pain and clicking from the joint Deviation on opening Muscle tenderness Mandibular displacement
what is mandibular displacement?
When there is inter-arch width discrepancies that cause the upper and lower cusps to meet
- mandible has to deviate to one side to avoid this and achieve ICP
what can a severe mandibular displacement of >4mm lead to in the future?
TMJ disease
what should the angle between the Frankfort plane and the long axis of the upper incisors be?
110 degrees
define a class I incisor relationship.
the incisal edges of the lower incisors occlude the cingulum of the upper incisors
define a class II div I incisor relationship.
the incisal edges of the lower incisors lie posterior to the cingulum of the upper incisors and the upper incisors are proclined or of average inclination
define a class II div II incisor relationship.
the incisal edges of the lower incisors lie posterior to the cingulum of the upper incisors and the upper central incisors are retroclined
define a class III incisor relationship.
the incisal edges of the lower incisors lie anterior to the cingulum of the upper incisors/the incisal edges occlude - reversed overjet
list the types of overbites (6)
Average - upper incisors overlaps/covers 1/2 to 1/3rd of lower incisor crown
Reduced
AOB - record how large it is and the maximal extent of teeth involved
Increased and complete contacts tooth
Increased and complete contacts the palate - doesn’t have to be traumatic
Increased but incomplete (doesn’t contact anything)
define a class I buccal segment relationship.
MB cusp of the upper 6 occludes with the buccal grove of the lower 6
define a class II buccal segment relationship.
MB cusp of the upper 6 occludes anterior to the buccal fissure/groove
define a class III buccal segment relationship.
MB cusp of the upper 6 occludes posterior to the buccal fissure/groove
define a class I canine relationship.
upper canine is posterior to the lower
define a class II canine relationship.
upper canine is anterior to the lower
define a class III canine relationship.
the upper canine is very posterior to the lower canine
what should be included on the orthodontic referral letter?
Name, age, sex of patient
HPC, RMH, RDH (relevant)
Incisor relationship and Skeletal base
Teeth present/absent, OH status and teeth with poor prognosis
Lower arch incisor inclination and crowing
Upper arch incisor inclination and crowing
OJ, OB centrelines, molar relationships, crossbites and any other information
IOTN (index of orthodontic need) score: this is how much the patient requires treatment from the point of dental health and improving their psychosocial wellbeing.
What is the IOTD score?
index of orthodontic need score: this is how much the patient requires treatment from the point of dental health and improving their psychosocial wellbeing.
how do we assess the anter-postero skeletal relationship clinically (2)
Palpate the skeletal bases
visual assessment
