Procedures in Orthodontics

Procedures in Orthodontics

Martyn Cobourne


It is important for the primary care practitioner to examine and diagnose occlusal problems in the developing dentition. This will provide a firm foundation for appropriate and timely referral to a specialist orthodontist. In addition, the local practitioner may be the first port‐of‐call for a patient with problems associated with their orthodontic appliance, and it is important for them to be able to manage these problems and provide appropriate advice. In many circumstances this will just require advice and reassurance until they can see their specialist; however, if the problem is acute and a source of pain and discomfort, then the practitioner should have sufficient knowledge to provide some relief. This chapter outlines the core principles associated with examination of the orthodontic patient and appropriate referral to a specialist. In addition, the management of orthodontic emergencies is also covered.

Orthodontic Examination


  • Dental mirror.
  • Dental probe.
  • Ruler.

Procedure Rationale
Medical history A comprehensive medical screening should be carried out as part of the orthodontic examination. This can be achieved with an anonymous patient questionnaire that is completed before the consultation. The following conditions should be noted:

  • Congenital heart defects.
  • Bleeding disorders.
  • Childhood malignancy.
  • Diabetes.
  • Immunosuppression.
  • Asthma.
  • Epilepsy.
  • Allergies.
  • Infectious disease.
  • Bisphosphonate use.
Extraoral examination The face should be looked at in both the relaxed and animated states in a position of natural head posture (the position that the patient naturally carries their head). Frontal and profile views should be undertaken.
Frontal examination: vertical relationship A normally proportioned face should subdivide vertically into approximately equal thirds:

  • Upper face (hairline to lower forehead).
  • Middle face (base of forehead to base of nose).
  • Lower face (base of nose to bottom of chin).

The lower third can be further subdivided into equal thirds covering the upper lip, lower lip and chin.

Frontal examination: the lips Lip competency should be evaluated:

  • Competent lips are together at rest.
  • Potentially competent lips are obstructed from contact, usually because of the position of the upper incisors.
  • Incompetent lips are unable to achieve an anterior oral seal.
Frontal examination: upper incisor show Around 3–4 mm of upper incisor should be on show at rest, whilst around 75–100% of the crowns should be shown on smiling.
Frontal examination: transverse relationship A normally proportioned face should subdivide transversely into equal fifths:

  • Ear to outer eye.
  • Eye.
  • Nose.
  • Eye.
  • Eye to outer ear.

The position of the dental centrelines should be noted in relation to the facial midline and any significant mandibular asymmetry.

Profile examination: anterior‐posterior jaw relationship A virtual vertical line (zero meridian) is dropped from the forehead with the face in natural head position and the position of the maxilla and mandible assessed in relation to this line.
In a class I case:

  • The upper lip should rest on this line.
  • The lower lip should be just behind this line.

In a class 2 case:

  • The lower jaw is >4 mm behind the upper

In a class 3 case:

  • The lower jaw is <2 mm ahead of the upper
Profile examination: vertical jaw relationship Intersection of the maxillary–mandibular plane angle with the back of the skull should be assessed:

  • If it coincides with the occiput it is considered normal.
  • If it is beyond the occiput this is reduced.
  • If it is in front of the occiput this is increased.

The frontal proportions of the face can also give a clue to the vertical jaw relationship. If the lower third of the face is proportionally larger than the other thirds, then the vertical jaw relationship is increased and vice versa.

Temporomandibular joints The temporomandibular joints should be examined for any obvious pain on palpation, crepitus, deviation, clicking or limited opening.
Intraoral examination The intraoral examination is concerned with the mandibular and maxillary dentitions in isolation and in occlusion. This should be done with the patient supine in the dental chair using a dental mirror. An overall assessment of dental health should be made, including oral hygiene, general dental condition to include any restorations, untreated caries, periodontal disease or previous dental trauma.
Dental arches
  • Mixed or permanent dentition.
  • Teeth present clinically.
  • Presence of crowding or spacing in the labial and buccal segments (as a general rule: 0–4 mm of tooth displacement is mild, 5–8 mm is moderate and >9 mm is regarded as severe crowding).
  • Tooth rotations.
  • Position and inclination of the labial segment in relation to the dental base.
  • Presence and position of the maxillary canines.
  • Inclination of the permanent canines.
  • Depth of any curve of Spee or Wilson.
Static occlusion The patient should be asked to occlude in the intercuspal position.
The incisor relationship should be classified:

  • Class 1: the lower incisor edges occlude or lie below the cingulum plateau of the upper incisors.
  • Class 2: the lower incisor edges occlude or lie behind the cingulum plateau of the upper incisors:
  • Division 1: the overjet is increased with proclined or upright incisors.
  • Division 2: the upper incisors are retroclined.
  • Class 3: the lower incisor edges occlude or lie ahead of the cingulum plateau of the upper incisors.

The overjet should be noted (normal, positive, negative) and measured.
The overbite should be in the range of 2–4 mm (normal, positive, negative) and measured. It can be increased or decreased from these dimensions. If there is no vertical overlap it is described as open.

  • The overbite is complete if there is contact between the incisors or the incisors and opposing mucosa.
  • The overbite is incomplete if there is no contact between the incisors or the incisors and opposing mucosa.

The maxillary and mandibular centrelines should be assessed in relation to the facial midline and to each other.
The buccal segment relationship should be classified in relation to the first permanent molars and canines.

For the molars

  • Class 1: the mesiobuccal cusp of the first permanent molar should occlude with the mesial buccal groove of the lower first molar.
  • Class 2: the mesiobuccal cusp of the first permanent molar is ahead of the mesial buccal groove of the lower first molar.
  • Class 3: the mesiobuccal cusp of the first permanent molar is behind the mesial buccal groove of the lower first molar.

For the canines:

  • Class 1: the maxillary canine should occlude directly in the embrasure between mandibular canine and first premolar.
  • Class 2: the maxillary canine is in front of the embrasure between mandibular canine and first premolar.
  • Class 3: the maxillary canine is behind the embrasure between mandibular canine and first premolar.

The severity of these relationships can be described in terms of tooth units (half or a full unit).
The presence of any anterior cross bites; or posterior buccal or lingual cross bites should be noted for each quadrant.

Functional occlusion Any discrepancy between intercuspal position and the retruded contact position should be noted.
The presence of canine guidance or group function in lateral excursion should be noted.
Summary A summary of the presenting features helps develop a list of problems.

Orthodontic Referral Criteria

Orthodontic treatment is commonly carried out in the late mixed and early permanent dentition. Appropriate referral to a specialist orthodontist is therefore important and it is the responsibility of the general dental practitioner to monitor development of the dentition in their patients. Orthodontic referrals should be made based upon clinical need at the appropriate time.

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Orthodontic treatment is generally carried out in four principle domains within the UK:
Hospital orthodontic service
Jan 22, 2018 | Posted by in General Dentistry | Comments Off on Procedures in Orthodontics
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