Introduction to Orthodontic Assessment

• History - reason for attendance:

  • Reason referred (often evident in the letter)
  • Ask the pt "what don't you like?", "what would you like to change?" - record the patient's concern
• History - medical history:

  • Allergies - nickel/latex/antibiotics
  • Medication, including inhalers
  • Management problems: epilepsy, diabetes
  • Treatment problems: possible tooth movement
  • Bleeding disorders
• History - dental history:

  • Motivation
  • Attendance history
  • Keen for orthodontics
  • Good dental health
  • Phobias (things like needles/extractions)
  • Trauma history
  • Ankylosis (because teeth wouldn't move as expected)
  • Root resorption
  • Loss of vitality
• Extra-oral examination:

  • Skeletal pattern
  • A-P (antero-posterior) relationship (I/II/III)
  • I = mandible 2-3mm posterior to maxilla
  • II = mandible retruded relative to maxilla
  • III = mandible protruded relative to maxilla
  • Vertical relationship
  • FMPA (Frankfort Mandibular Planes Angle)

  
• Extra-oral examination:

  • Skeletal pattern
  • A-P (antero-posterior) relationship (I/II/III)
  • I = mandible 2-3mm posterior to maxilla
  • II = mandible retruded relative to maxilla
  • III = mandible protruded relative to maxilla
  • Vertical relationship
  • LFH (lower face height)

  
• Extra-oral examination:

  • Skeletal pattern
  • A-P (antero-posterior) relationship (I/II/III)
  • I = mandible 2-3mm posterior to maxilla
  • II = mandible retruded relative to maxilla
  • III = mandible protruded relative to maxilla
  • Vertical relationship
  • LFH (lower face height) & FMPA (Frankfort Mandibular Planes Angle)
  • Asymmetry

  
• Extra-oral examination:

  • Soft tissues
  • Lips (competent/incompetent)
  • NLA (nasolabial angle)

  
• Extra-oral examination:

  • Soft tissues
  • Lips (competent/incompetent)
  • NLA (nasolabial angle)
  • Lip/smile line (average amount of tooth and gingivae shown when smiling)

  
• Extra-oral examination:

  • Soft tissues
  • Lips (competent/incompetent)
  • NLA (nasolabial angle)
  • Lip/smile line (average amount of tooth and gingivae shown when smiling)
  • Here all teeth and gingival tissues are shown when smiling - therefore has high smile line

  
• Extra-oral examination example:

  • Skeletal:
  • Skeletal classification = II
  • FMPA (Frankfort Mandibular Planes Angle) = reduced
  • LFH (lower face height) = reduced
  • Soft tissues:
  • Lips = competent
  • Nasolabial angle = average
  • Asymmetry present

  
• Skeletal pattern - anteroposterior:

  • Class I; mandible 2-3mm posterior to maxilla
  • Class II; mandible restrusive to maxilla
  • Class III; mandible protruded relative to maxilla

  
• Skeletal pattern - vertical examples:

  • LHS = average LFH and average FMPA (Frankfort Mandibular Planes Angle)
  • Middle = steep angle between maxillary and mandibular plane
  • RHS = low angle between maxillary and mandibular plane and a reduced face height

  
• Skeletal pattern: transverse skeletal discrepancy - mandible is longer on the RHS, resulting in the chin point being deviated to the left - centreline of teeth also off to the left

  
• Intra-oral examination:

  • Teeth present
  • Oral hygiene - good/fair/poor
  • Periodontal state; BPE
  • Identify teeth of poor prognosis
  • Deciduous, restorations, caries, etc.
• Intra-oral examination of upper and lower arches:

  • Crowding
  • Mild (<4mm)
  • Moderate (4-8mm)
  • Severe (>8mm)
  • Severely displaced teeth
  • Proclined or retroclined incisors
  • Tooth size discrepancies
  • Canines: angulation/palpation
• Mild crowding in upper labial segment. Upper incisors are slightly proclined. Case is complicated by heavy restorations.

  
• Severe crowding in the upper labial segment with a severely displaced upper right canine. Upper central incisors are rotated and mildly proclined. Large molars with extra cusps. Right canine is distally orientated, where as left canine is more upright.

  
• Incisor relationship = Class I: lower incisor edges occlude with or lie immediately below the cingulum plateau of the upper central incisors

  
• Incisor relationship = Class II: lower incisor edges lie posterior to the cingulum platuea of the upper central incisors. Div 1 = upper incisors are proclined, with an increased overjet.

  
• Incisor relationship = Class II: lower incisor edges lie posterior to the cingulum platuea of the upper central incisors. Div 2 = upper incisors are retroclined, with minimal overjet.

  
• Incisor relationship = Class III: lower incisor edges lie anterior to the cingulum plateau of the upper central incisors. Overjet is reduced or reversed.

  
• Overjet is measured in mm.

  
• Overbite is measured in % or mm. It can be complete or incomplete, and may impact the opposing teeth or soft tissues.

  
• Centrelines - example:

  • Absent upper lateral incisor leading to off-centre centreline

  
• Occlusion - buccal:

  • Canines
  • Class I - upper 3 occludes directly in embrasure between lower 3 & 4
  • Molars
  • Class I - MB cusp of upper 6 occludes with MB groove of lower 6

  
• Examples of canine and molar occlusal relationships.

  
• Occlusion - crossbites:

  • Buccal crossbite
  • Lingual crossbite
  • Anterior crossbite
  • Unilateral or bilateral
  • Mandibular displacement

  
• Radiographs:

  • Early: will it change your treatment
  • <9 years old if teeth unerupted
  • >9 years old submerging deciduous molars
  • >9 years old canines not palpable
  • Suspect hypodontia/ectopic teeth
  • Permanent dentition: necessary to assess for definitive orthodontic care