Orthodontic Assessment Flashcards
Why do we carry out an orthodontic assessment?
Dentists carry these out to:
- Determine if any malocclusion is present
- Identify any underlying causes (if can do this then are halfway there to treating the problem)
- Decide if treatment is indicated
o Would then either refer or devise a treatment plan
When are orthodontic assessments carried out?
Patients will have a brief orthodontic examination at approx. 9 years old and a comprehensive examination when premolars and canines erupt (11-12 years).
Other times an orthodontic assessment may be carried out is if an older patient presents to you for the first time or if a malocclusion develops later in life.
What is ‘ideal occlusion’?
is the gold standard by which occlusal irregularities may be judged against
What are Andrew’s 6 keys (the 6 things required for ideal occlusion)?
i. Molar relationship – The distal surface of the disto-buccal cusp of the upper first permanent molar occludes with the mesial surface of the mesio-buccal cusps of the lower second permanent molar. (Must have class 1 molar relationship)
ii. Crown angulation (mesio-distal tip)
iii. Crown inclination (relating to incisors)
iv. No rotations
v. No spaces
vi. Flat occlusal plane
What is ‘normal occlusion’?
Occlusions that have minor deviations that do not constitute to an aesthetic or functional problem
What is a malocclusion?
more significant deviations from the ideal that may be considered unsatisfactory (aesthetically or functionally)
Do all malocclusions need treatment?
No most don’t but some will (patient factors may influence decision)
What are the steps in your history taking?
Sane as other disciplines in dentistry:
- PC
- Hx of presenting complaint
- PMH
- PDH
- social/fam Hx
extra ones would be any habits and expectations of treatment
In the presenting complaint and hx of presenting complaint, what things do you need to consider/think of asking?
PC: -If the patient comes in with 3 or 4 complaints then ask the patient to put them in order of importance
-Want to ask the patient how much does the idea of a brace bother them? – You need to wait till the patient is ready to do any ortho work
Hx of presenting complaint:
-How quickly has it happened? (If something has developed quickly then this may indicate further problems that need investigations)`
What are a few medical conditions/things in medical history that are a contraindication to orthodontic treatment?
- Allergy to Nickel or Latex
- Epilepsy/epileptic drugs (Epileptic drugs can cause gingival hyperplasia which can make it very difficult for braces to be cleaned)
- Drugs
- Imaging
What info do you want to get from a patients past dental history for ortho?
- Frequency of attendance
- Nature of previous treatment
- Have they had a lot? Are they high caries risk and therefore not suitable?
- No treatment then referring for an extraction? May be hard for the patient to cope with
- Co-operation with previous treatment
- Trauma to permanent dentition
- Has there been previous trauma? E.g. RCT then required? Is there root resorption?
What questions/info do you want to get from the social/family history?
- Travelling distance/time (Is it better to treat here or somewhere closer to them? Need lots of appointments for ortho – check-ups etc)
- Car owner/public transport?
- Parents work? – need the parents for consent
- School exams? – often need to work around situations like this
What habits do you want to ask about in the Hx of the patient?
- Thumb sucking
- Lower lip sucking
- Tongue thrust
- Chewing finger nails
What can chewing finger nails predispose the patient to ?
Increased root resorption
In the extra-oral exam, what do you want to look at? Why might you compare the patient to their parent?
- the skeletal bases, soft tissues and TMJ
- to get an idea of the patient’s growth potential and any malocclusion (particularly relevant for Class III malocclusion)
The facial skeletal pattern is considered in what 3 planes?
- antero-posterior
- vertical
- transverse
How can skeletal assessment be done in the antero-posterior plane?
Visual assessment or by palpating the skeletal bases
What are the 3 skeletal classes that a patient can fall into? Describe them.
- Class I = Maxilla 2-3mm in front of the mandible
- Class II = Maxilla more than 3mm in front of the mandible
- Class II = mandible in front of the maxilla
How would you carry out a visual assessment of the skeletal bases (skeletal class)?
Patient’s Frankford plane to be horizontal to the ground.
The innermost curvature of the upper lip determines position of the maxilla and innermost curvature of lower lip determines position of mandible
Note: the chin is separate from these measurements
When would palpating the skeletal bases to assess them be useful?
Can always be useful but especially in Class III patients as there can be quite a lot of soft tissue and a thick lip.
Palpation can change what seems to be a mild class III to a severe class III.
In visual assessment from the vertical plane, what are you looking to assess?
The Frankford - mandibular planes angle (FMPA)
How do you assess the Frankford-Mandibular Plane angle? Also, what are these two planes?
Frankford plane - the highest point on the upper margin of the opening of the external auditory canal and the low point on the lower margin of the orbit
Mandibular plane - lower border of the mandible
You assess the FMPA by using your fingers or rulers to ‘line’ them. The 2 lines/planes should ideally meet at the back of the head
In a reduced FMPA angle, what would you expect?
A deep bite
What are competent/incompenet lips?
Competent = lips that meet at rest i.e. when the mentalis muscle is relaxed
Incompetent = lips do not meet at rest when the mentalis muscle is relaxed. (There is nothing wrong with incompetent lips but they can influence tooth position)
What is a lip trap and what is the problem with it?
- where the teeth are sat on or in front of the lower lip
- It may procline the upper incisors and may also lead to relapse of overjet if it persists at the end of treatment.
What can tongue thrusting when swallowing be associated with?
An anterior open bite
Describe mandibular displacement.
- This is when there is a discrepancy in the retruded contact and inter-cuspal position
- RCP does not equal ICP
- If the discrepancy is more than 4mm then can cause TMJ problems
What is a class III incisor relationship?
The lower incisor edges lie anterior to the cingulum plateau of the upper incisors. The overjet is reduced or reversed.
When assessing an overbite, what do we want to consider?
- think is the overbite average, reduced or an AOB?
- Is it increased, incomplete or complete?
- Is it contacting the teeth or the palate?
- Is it causing any trauma to the palate?
Explain/describe the classes of the angles classification for buccal segment relationships.
- Class I = The mesial buccal cusp of the 1st upper permanent molar occludes with mesio-buccal groove on the lower first permanent molar. The upper canines sit behind the lower canines.
- Class II = The upper mesial buccal cusp occludes anterior to the fissure. The upper canines are anterior to lowers.
- Class II = The upper mesial buccal cusp occludes behind the mesio-buccal groove. The upper canines sit behind the lower canines.
What is a crossbite?
An abnormal relationship of one or more teeth of one arch to the opposing tooth or teeth of the other arch due to labial, buccal, or lingual deviation of tooth position, or to abnormal jaw position.
Note: The upper pic shows posterior crossbite and the lower pic shows a posterior and anterior crossbite.
