Dentofacial assessment of orthognathic patient

1. Dentofacial assessment of
orthognathic patient
Part 1
Prof Dr Maher Fouda
Faculty of Dentistry, Mansoura University .
Mansoura, Egypt

3. Assessment of the orthognathic patient
should be carried out systematically to
ensure that a complete picture of the
presenting dentofacial dysmorphology is
assembled .

4. A pro-forma may be helpful in guiding the
clinician through the assessment in planned
sequence and documenting the findings in a
structured manner.

5. General assessment
Because orthognathic surgery is largely elective in
nature, the patient’s concerns are the main reason
for pursuing treatment and must be carefully
elicited from the outset.

6. Whilst most patients will describe one or
more clear problems, some will be more
vague and will have to be probed more
thoroughly to establish exactly what they
are seeking to derive from treatment.
General assessment

7. General assessment
In general, patients’ concerns fall into the
following categories: 1. Functional problems: a.
Difficulty with biting and chewing.

8. General assessment
b. Discomfort due to the malocclusion: i. Palatal
or gingival soft tissue trauma (e.g. deep
overbite). ii. Dental trauma (e.g. limited tooth
contact). c. Temporo-mandibular joint
dysfunction. d. Speech difficulties
Functional problems:

9. General assessment
2. Aesthetic problems: a. Facial appearance. b.
Dental appearance. c. Gingival display.

10. If the psychologist can be present on the clinic
when the patient is being examined, this is
valuable in helping the patient to express their
concerns and the clinicians to understand them
General assessment

11. Medical, dental and social history
As with any surgical or dental patient, a full medical
history should be taken prior to clinical examination
if the patient reports any significant illnesses at initial
assessment it is prudent to contact the General
Medical Practitioner or Consultant Specialist for
clarification or further investigation .

12. Medical, dental and social history
It is important to establish the patient’s level of
dental motivation and ensure that they will have the
ongoing support of a General Dental Practitioner for
the duration of their treatment.

13. If there is a history of dental anxiety it is important
to make sure that the patient will be able to cope
with the challenges of surgical orthodontic
treatment
Medical, dental and social history

14. Medical, dental and social history
A patient’s social history should at least include
questioning about home circumstances, smoking
and alcohol consumption.

15. It is also important to know about any history of
mental health problems, but specialist
questioning in this area is most appropriately
undertaken at the psychology interview.

16. History of dentofacial dysmorphology
A history should be taken from the patient regarding the
development of their dentofacial problems. This should
include the following: 1. Congenital anomalies (e.g. growth
abnormalities, condylar hypoplasia or agenesis, hemi-facial
microsomia).

17. 2. Familial traits (i.e. other family members with facial
dysmorphology, such as class III jaw relationship).
History of dentofacial dysmorphology

18. History of dentofacial dysmorphology
3. Acquired anomalies: a. Traumatic (e.g. TMJ
trauma, before and after cessation of growth). b.
Pathology (e.g. pituitary adenoma).

19. History of dentofacial dysmorphology
4. Racial characteristics: a. Anterior bi-maxillary
protrusion (Black African, Chinese). b.
Zygomatico-maxillary hypoplasia (Asian).

20. History of dentofacial dysmorphology
It is important to recognise progressive facial
dysmorphology, which most commonly manifests
as follows: 1. Gradual increase in anterior open bite
(e.g. idiopathic condylar resorption). 2. Progressive late
mandibular growth (e.g. pituitary adenoma)

21. 3. Progressive mandibular asymmetry: a. Unilateral condylar
hyperplasia. b. Unilateral condylar resorption. c. Unilateral
condylar tumour (e.g. osteochondroma). d. Hemi-mandibular
elongation. e. Hemi-mandibular hypertrophy.
History of dentofacial dysmorphology

22. It is important to elicit the most accurate possible history
regarding the progress of these conditions. Previous family or
school photographs, if available, can be extremely helpful .
History of dentofacial dysmorphology

23. Stature and body form
The patient’s height and general body shape should be
noted early on in the assessment, since orthognathic
treatment should be aimed at delivering facial
proportions that are in keeping with the patient’s build.

24. A tall, lean patient is unlikely to suit a
disproportionately reduced lower anterior face height
and a short, broad patient is unlikely to suit an
increased lower anterior face height.
Stature and body form

25. Stature and body form
Similarly, a patient’s stature may influence the surgical
plan in the anteroposterior plane. For example, in
certain class III patients, standing height might play a
part in deciding whether surgical correction would be
by means of a maxillary advancement or a mandibular
setback

26. Where a patient is clearly overweight this can be
a contra-indication for elective orthognathic
surgery. In such cases, the patient may be
required to reduce their weight before they can
be considered for treatment. The Body Mass
Index (BMI) is helpful as a guide.
Stature and body form

27. • The BMI is computed by dividing the person’s
weight in kilograms (kg) by their height in meters
squared (m2).
• In men, obesity is defined as a BMI of 27.8; for
women, obesity is a BMI of 27.3.

28. Facial assessment
Lateral view
The patient should be seated comfortably with their
back in an upright position and asked to adopt their
natural head posture (NHP), in which they are generally
viewed in everyday life. This can be made easier by
asking them to look in a mirror mounted straight ahead
of them.
The patient’s head posture can affect the
clinical impression of their
antero-posterior jaw relationship

29. Lateral view
The patient’s head posture can
affect the clinical
impression of
their antero-posterior jaw
relationship
The alternative method of positioning the Frankfort Plane (FP)
parallel to the floor may place them in an artificial position, since this
not a reliable horizontal reference plane in patients with significant
facial skeletal discrepancies. It has been shown that NHP is more
reliable than FP for orientation of the head. Inappropriate head
positioning can result in a false perception of the antero-posterior jaw
relationship

30. Habitual tilting of the head to the left or right side should be
avoided. However, for patients that have a condition that
produces involuntary tilting, such as tortocollis (due to
shortening of one of the sternomastoid muscles), this
should be accepted as their normal posture, as it is unlikely
to improve as a result of surgery.

31. It is important for the peri-oral soft tissues to be relaxed,
particularly in patients with increased vertical proportions,
who may have incompetent lips and will tend to habitually
posture them together through mentalis muscle hyper-
activity.

32. Viewing the face from the lateral aspect allows the
assessment of: • Jaw relationship and facial convexity. •
Forehead. • Infra-orbital rims. • Nose. • Para-nasal region. •
Upper lip. • Lower lip and chin. • Lower lip to sub-mental
plane angle. • Mandibular plane angle

33. Jaw relationship and facial convexity: The left and right
sides of the head should be examined separately, since
characteristic differences will be detected in asymmetric
faces

41. Or Soft tissue subspinale is the point
of greatest concavity in the midline of
the upper lip between subnasale (Sn)
and labrale superius (Ls) .

51. changes of facial convexity (FC) in Class III patients (c =
presurgery, d = postsurgery) revealed high significance.

63. The relative antero-posterior positions of the maxilla and mandible,
as well as the convexity of the profile, can be assessed subjectively
by looking at the patient’s profile in natural head position. The facial
convexity can also be measured objectively on a profile photograph,
including or excluding the nose, as illustrated in Figure 2.2a.

64. A class II jaw discrepancy will generally manifest as a
convex profile (Figure 2.2b), while a class III profile will be
concave (Figure 2.2c)

65. In some class III cases, the drape of the upper lip can mask
the underlying maxillary deficiency to large extent and
present a deceptively normal soft tissue profile .
This is most likely in high angle cases where there is a degree of
bi-maxillary retrusion owing to the downward and backward
position of the chin

66. In class II cases, maxillary protrusion is uncommon,
relative to the patient’s racial norm, but it is not
uncommon to see bi-maxillary retrusion, particularly in
patients with long facial types.

67. In class III cases, maxillary deficiency is common but again,
in high angle cases, bimaxillary retrusion with retrogenia
can be present

68. In such cases, the telltale signs of maxillary
deficiency will be present, such as para-nasal
hollowing (Figure 2.3)

69. Forehead
It is important to note the position and shape of the forehead, since it is one of
the parts of the face that will remain completely unchanged by orthognathic
surgery. If frontal bossing is present or the forehead is flat, this should be taken
into account when assessing the jaw positions and the effects of surgery, such
that harmonious facial balance will be achieved.

70. The shape of the nasal dorsum and the angle of the nasal tip may be affected
by maxillary osteotomy and it should be carefully noted whether or not such
changes are likely to be favourable. For example, a patient with maxillary
deficiency who already has an up-turned nasal tip is likely to experience a
worsening of this feature with a Le Fort 1 advancement osteotomy.
Nose

71. On the other hand, a patient with a long facial type and a
down-turned nasal tip may well
experience an improvement in their nasal profile as a result of Le Fort 1
impaction osteotomy. In addition, an assessment of the prominence of the nose
in relation to the forehead and chin is essential, in diagnosing the jaw
discrepancy and planning the required surgical correction (Figure 2.2).

72. The contour of the skin overlying the area just lateral to the alar base can be
seen from the side view. A lack of bony support for the soft tissues in this
region will produce a depression described as para-nasal hollowing, which is
indicative of low level antero-posterior maxillary deficiency (Figure 2.3).
Although most commonly associated with class III jaw discrepancies, it can
also be present in class II cases with bi-maxillary retrusion.
Para-nasal region

73. Upper lip
It is important to assess the form and angle of the upper lip.
The naso-labial angle is often taken as an indication of the
position of the underlying maxilla and incisors. However, it is
prone to variation according to the slope of the columella and
the curvature of the upper lip and the angle can be measured
in a number of different ways

74. Upper lip
. A patient with maxillary deficiency will tend to show an
increased naso-labial angle .

75. Upper lip
However, an unusually short upper lip may be more furled than
average, or the columella may be down turned, giving rise to an
acute angular measurement, even in the presence of maxillary
deficiency .

76. Conversly some patients present with a deficient maxilla but the
proclined upper anterior teeth support the upper lip.