Extra-Oral

• Record the skeletal pattern:
  • See 'The fundamentals of orthodontics' for the different skeletal pattern classifications.
    • *These involve looking in the antero-posterior plane - meaning looking at the person from side on, and assessing the jaw relationship from front to back.
• Assess for any facial asymmetry (transverse jaw relationship) and record in notes.  
• Assess the vertical jaw relationship:
  • The face can be divided into thirds:
    • Top 1/3: top of forehead to the glabella (between the eyebrows) = UAFH (upper anterior face height)
    • Middle 1/3: glabella to subnasale (base of nose)
    • Lower 1/3: subnasale to menton (base of chin) = LAFH (lower anterior face height)
  • An average face will have UAFH = LAFH
  • Record whether any of these thirds are increased/reduced 
  • These facial heights can have an influence on the teeth. 
    • A reduced LAFH may relate to a deep overbite.
    • An increased LAFH may be associated with an AOB (anterior open bite)

• Assess soft tissues:
  • Lips: are they competent (meet at rest) / incompetent (apart at rest).
    • Make a note of whether the lower lip is in front / below / behind the upper incisors, as this can influence treatment. 
  • Tongue: a large tongue which thrusts upon swallowing can influence where the teeth are.
  • Habits: thumb sucking can lead to:
    • Anterior open bite
    • Increased overjet
    • Proclined upper incisors / retroclined lower incisors
    • Upper arch narrowness
  • If pt has a habit, this must be stopped before treatment begins.
• Assess TMJ:
  • Ask pt if they experience any pain, clicking or limitation of mouth opening before treatment and assess these appropriately – as in a routine E/O examination.

Intra-Oral

• Start with recording the teeth present. 
• Assess the teeth in occlusion: 
  • incisor relationship, canine relationship and molar relationship (remember the permanent teeth have to be there for this to occur). 
• Assess the overjet. – the distance between the tip of the most prominent upper incisor to the labial aspect of the lower incisor. 
  • A normal overjet = 2-4mm
  • A reverse overjet is when the lower incisors lie in front of the upper incisors: this is still measured and recorded.

• Assess the centre lines and record and shifts, by how many mm and in what direction. 
• Assess any posterior cross bites.
• Assess for any scissor bites: 
  • This is when a maxillary molar or premolar may occlude completely out of the arch and can cause trauma or mandibular displacement when biting. 
• Assess for any posterior open bites (where the posterior molars do not meet in occlusion).
• Assess both the mandibular arch and maxillary arch for:
  • Labial Segment:
    • Crowding/Spacing
    • Rotations
    • Inclination of incisors 
  • Canine angulation in relation to the occlusal plane. This can be average/proclined/retroclined. 
  • Buccal Segment:
    • Are molars well aligned/crowded/spaced?
    • Are there any problems with infra-occlusion of primary teeth?

• Make a note of Oral Hygiene – this will be important if treatment will commence. 
• Assess caries risk, periodontal stability, any trauma/previous trauma, attrition and erosion risks. 
• Use the IOTN to grade the malocclusion: See our ‘IOTN Made Simple’ page for details.  

Here's a handy checklist for you to print and use when conducting an orthodontic assessment:

Conducting an Orthodontic Assessment Handout