Soft tissue cephalometric analysis for orthognathic surgery
DR ARIF ISMAIL
• CEPHALOMETRIC LANDMARKS USED FOR THE
• HORIZONTAL ANALYSIS FOR THE SOFT TISSUE
• VERTICAL ANALYSIS FOR THE SOFT TISSUE
Treatment planning for patients who require
orthognathic surgery should include both a hard
tissue and soft tissue cephalometric analysis.
A good facial profile reflects harmony between
many facial areas that are dependent on tooth
position, bone position and soft tissue mass. Thus
soft tissue areas such as the neck, nose and lilps
must be considered in determining whether
prognathism or retrognathism of the jaw exists.
The mean standard deviations for the
measurements used in this soft tissue analysis
were derived from a population of 40 white adults
(20 men and 20 women) – between the ages of 20
and 30. All patients in the sample were
orthodontically untreated with class I occlusions
and had vertical facial proportions that were
determined to be within normal limits (N.
ANS/ANS. Me was between 0.75 and 0.85)
HORIZONTAL ANALYSIS OF THE SOFT TISSUE
ANALYSIS OF THE FACIAL CONVEXITY
• G to Sn and Sn to Pog
• Mean Value is 12 degree
with a standard deviation of
• Clockwise opening of the
angle shows a positive value
and vice versa.
• Positive value suggests of a
class 2 pattern
• Negative value suggests of a
class 3 pattern
HOWEVER THE ANALYSIS OF THIS ANGLE DOES
NOT TELL WHETHER THE MAXILLA OR THE
MANDIBLE IS ACCOUNTABLE FOR THE POSSIBLE
SO TO DEFINE THE ANTERIOR POSTERIOR
POSITION OF THE JAWS TWO SOFT TISSUE
MEASURES ARE TAKEN.
Sn point to G perp
6 +/- 3 mm
Pog’ point to G perp :
0 +/- 4 mmm
NASION CUTANEOUS ( NA’) POINT :
• Also known as Sellion, is the
deepest soft tissue point of the
• Ideally it is located about 6mm
above the canthus, between
the supratarsal fold and the
upper palpebral margin and
approximately 9 to 13 mm
anterior to the corneal
• Distance from Glabella 4 to
• Na’ forms the apex of
the nasofrontal angle
formed by the
intersection of two
lines, a tangent to the
glabella (G - Na’) and
the other tangent to
pronasale (Pn – Na’).
• Normal Value of this
angle : 120 to 135
• The antero-posterior and vertical position of the nasofrontal angle apex is very important in the planning
stage and is crucial for both pre-surgical planning and
• Marking off the ideal nasion cutaneous will allow to
define the nasofacial angle which estabilishes the ideal
dorsal line ( Pn – Na’) and contributes to the new
projection of the tip
It is the angle formed by
the intersection of the
dorsal line with the
The angle is 34 degree
among Women and 36
degree among Men.
ANGLE OF TIP
• It is formed by the
inttersection of the true
vertical with the
pronasale line –
posterior alar point.
• The ideal value for the
angle of the tip is 105
degree for Women and
100 degree for Men
• Formed by the intersection of
lines Cl-Sn and Sn-Ls.
• Mean Value is 102 degree with a
standard deviation of 8 degree.
• It is divided into two
components, upper and lower, by
a true horizontal intersecting the
Sn. In the diagnosis of surgical
cases the upper nasolabial angle
is analysed seperately from the
lower, in search of components
involved in the alteration and for
an appropriate surgical solution.
LOWER CERVICOFACIAL ANGLE
• Formed by the intersection
of Sn – Gn’ and Gn’ – C
• Mean Value is 100 degree
with a SD of 7 degree.
• A Mandibular set back
cannot be carried out if the
angle is more than 90
instead, the use of another
procedure to preserve the
anteroposterior position of
1. HEIGHT OF THE MID THIRD OF THE FACE/
HEIGHT OF THE LOWER THIRD ( A / B)
• The mean value of the ratio is 1:1 , deviations of about 5% are
• Height of the lower third of the face increases in :
a) Maxillary vertical over growth
b) Class 3 patients with vertical height increase
c) Skeletal open bites
Height of the lower third of the face decreases in :
a) Maxillary Vertical undergrowth
b) Mandibular retrusion with deep bite
c) Vertical undergrowth of the chin
• The length of the lip should be approximately 1/3 of the
height of the mid third of the face.
• When the upper lip is less is anatomically short ( less
than 18mm ) it is associated with an increase in the
inter labial distance and an excessice exposure of the
upper incisor even though the lower third has a normal
• Norm : Male
22 +/- 2mm
20 +/- 2mm
• It is the distance between the stomion superioris and the border
of the upper incisor.
• The Mean Distance is 1 – 3 mm.
• At rest , 2 t0 2.5 mm of crown exposure is desirable for a
• In men , exposure of the upper incisor is lesser than women.
• In patients with anterior maxillary vertical over growth –
excessive exposure of the upper incisors at rest – “Gummy
• Excessive exposure of lips can also occur because of short lip.
In these patients orthodontic treatment might be of help to
intrude the upper anterior sector.
• It is the relationship of the length of the upper lip to the
mid third of the face.
• In a harmonius face , the normal ratio is approximately
• It allows to check whether the upper lip length is in tune
with the face under study.
6. SN – STS / STI – ME’ , MEASURE C / MEASURE D
• The length of the upper lip equals half the length of the
lower lip.( Ideal Ratio – 1 : 2 )
• The average length of the lower lip ranges from 38 to
• Anatomically short lower lip is related to Class II , and
conversely , anatomically long lower lip is related to
• Anatomically Short lower lip is corrected by
• Treatment using hard tissue cephalometric
standards may not lead to the desired
improvement in facial form.
• The soft tissue analysis evaluates both vertical
and horizontal aspects of the face, including lip
length and posture.
• The prime objective of orthognathic surgery is
facial improvement, therefore soft tissue
analysis becomes paramount in treatment
• ORTHODONTICS AND ORTHODONTIC SURGERY –
DIAGNOSIS AND PLANNING , JORGE GREGORET
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