Burstone

INTRODUCTION
The introduction of radiographic cephalometrics in
1934 by Hofrath in Germany and Broadbent in the United
states provided both a research and a clinical tool for the
study of malocclusion and underlying skeletal
disproportions. Cephalometric films could be used to
evaluate dentofacial proportions and clarify the anatomic
basis for a malocclusion. The orthodontist needs to know
how the major functional components of the face (cranial
base, jaws, teeth) are related to each other. Any
malocclusion is the result of an interaction between jaw
position and the position the teeth assume as they erupt,
which is affected by the jaw relationship.
www.indiandentalacademy.com

A cephalometric analysis especially designed for
the patient who requires maxillofacial surgery was
developed to use landmarks and measurements that
can be altered by common surgical procedures.
Because measurements are primarily linear, they may
be readily applied to prediction overlays and study cast
mountings and may serve as a basis for the evaluation
of post treatment stability.

The successful treatment of the orthognathic
surgical patient is dependant on careful diagnosis.
Cephalometric analysis can be an aid in the diagnosis of
skeletal and dental problems and a tool for stimulating
surgery and orthodontics by the use of acetate overlays.
The first step in the diagnosis of the orthognathic
surgical patient is to determine the nature of dental and
skeletal defects.

Patients who require orthognathic surgery
usually have facial bones as well as tooth positions
that must be modified by a combined orthodontic
and surgical treatment. For this reason, a specialized
cephalometric appraisal system, called
CEPHALOMETRICS FOR ORTHOGNATHIC
SURGERY (COGS) was developed at The University
of Connecticut.

The COGS system describes the horizontal and
vertical position of facial bones by use of a constant
co-ordinate system. The sizes of bones are represented
by direct linear dimensions and their shapes, by
angular measurements. The standards are based on a
sample obtained from the child research council of
The University of Colorado school of medicine
through 16 females and 14 males.

ADVANTAGES
 The chosen landmarks and measurements can be
altered by various surgical procedures.
 The comprehensive appraisal includes all the facial
bones and a cranial base reference.
 Rectilinear measurements can be readily transferred
to a study cast for mock surgery.
 Standards and statistics are available for variations
in age and sex from ages 5 to 20 on the basis of
developmental age.
 Critical facial skeletal components are examined.
 A systematized approach to measurement that can
be computerized is used.

The COGS appraisal describes
 Dental,
 Skeletal
 Soft tissue variations.

SKELETAL VARIATIONS

Ar
Go
Me Gn
Pg
B
Ans
Pns
Ptm
N
S
A

SELLA (S) : Centre of pituitary fossa.
NASION (N) : Most anterior point of nasofrontal
suture in the midsagittal plane.
ARTICULARE (Ar): Intersection of basisphenoid and
posterior border of the condyle.
PTERYGOMAXILLARY : Most posterior point on the
FISURE (PTM) anterior contour of maxillary
tuberosity.
SUB SPINALE (A) : Deepest point in midsagital plane
between ANS and Prosthion.

POGONION (Pg) : Most anterior point in
midsagittal plane of the
contour of the chin.
SUPRAMENTALE (B) :Deepest point in the
midsagittal plane between
Infradentale and Pg.
ANS : Most anterior point of nasal
floor.
MENTON (Me) : Lowest point of the contour
of mandibular symphysis.

GNATHION (Gn) : Mid point between Pg and
Me
MANDIBULAR PLANE : Plane constructed
(MP) from Me to the angle
of Mandible (Go)
NASAL FLOOR (NF) : Plane constructed from PNS
to ANS
GONION (Go) : Located by bisecting
posterior ramal plane and
MPA

I. CRANIAL BASE
The baseline for comparison of most of the data in this
analysis is a constructed plane called HORIZONTAL
PLANE (HP), which is a surrogate Frankfort plane,
constructed by drawing a line 7 o from the line S to N.

HP
Ar-Ptm
Ptm -N

Cranial base is measured as the length from Ar to N,
parallel to HP. Ar –N is a relatively stable anatomical
plane, however it can be changed by cranial surgery
that affects N, such as Le fort II and III osteotomies.
Ar –N is also slightly altered with auto correctional
rotations of mandible, where Ar moves closer to N.

Ar- PTM
Measured parallel to HP to determine horizontal
distance between posterior aspects of mandible and
maxilla. The greater the distance between Ar-PTM,
the more the mandible will lie posterior to the maxilla,
assuming that all other facial dimensions are normal.
Therefore, one factor for prognathism or
retrognathism can be evaluated by this measurement
of cranial base. www.indiandentalacademy.com

II. HORIZONTAL SKELETAL PROFILE
Here all the measurements are made parallel
to HP, since most surgical corrections are primarily
done in anteroposterior direction. These include:

A. Degree of Skeletal Convexity
The N-A –Pg (Angle)
gives an indication of the
overall facial convexity. A
positive (+) angle of
convexity denotes a convex
face; a negative (-) angle
denotes a concave face. A
perpendicular from HP is
dropped through N. The
horizontal position of A is
measured to this
perpendicular line ( N-A).

N-A-Pg
A
Pg
N
Hp

This measurement describes the apical base of maxilla in
relation to N and enables the clinician to determine if
the anterior part of maxilla is protrusive or retrusive.
Useful in planning treatment of anterior maxillary
horizontal advancement or reduction, and of total
maxillary horizontal advancement or reductions.
B. N-B
Also measured in a plane parallel to HP from the
perpendicular line dropped from N. This
measurement describes the horizontal position of the
apical base of mandible in relation to N.
Useful in planning the treatment of anterior
mandibular horizontal advancement or reduction and
the total mandibular horizontal advancement or
reduction.

C. N- PG
Measured in the same manner as N-A and N-B and
indicates the prominence of the chin. This
measurement helps to determine if there is a
horizontal genial hyperplasia or hypoplasia.
Useful in the planning of treatment augmentation or
reduction genioplasty, of anterior mandibular
horizontal advancement or reduction, and of total
mandibular horizontal advancement or reduction.
Thus we can see that the measurements of the
horizontal skeletal profile represents
 Facial convexity
 Horizontal relationship of apical base A and B
points
 And the chin positions related to N.www.indiandentalacademy.com

Pg
B
A
HP

III. VERTICAL SKELETAL AND DENTAL
A. SKELETAL
A vertical skeletal discrepancy may reflect an anterior,
posterior or complex dysplasias of face. Vertical
skeletal cephalometric measurements are divided into
 Anterior components
 Posterior components

Anterior components is
subdivided into
Middle third
facial
height :
Distance
from N to
ANS is
measured
perpendicul
ar to HP.
Lower third
facial
height :
ANS – GN,
measured
perpendicul
ar to HP

Ans
Pns

Posterior components is subdivided into :
a. Posterior maxillary height : Length of
perpendicular line dropped from HP intersecting
PNS
b. Divergence of mandible posteriorly : Shown
by MP – HP Angle.
Vertical skeletal measurements of the anterior
and posterior components of the face will help in
the diagnosis of anterior, posterior, or total
vertical maxillary hyperplasia or hypoplasia, and
clockwise or counter - clockwise rotations of the
maxilla and mandible.www.indiandentalacademy.com

HP
Posterior
maxillary height
MPHP
MP-HP

The typical surgical correction of these problems
include total maxillary vertical advancement or
reduction, anterior maxillary vertical augmentation or
reduction, posterior maxillary vertical augmentation
or reduction, combinations of the above two and
mandibular ramus rotation and ramus height
reduction.

B. Dental
Assessment of vertical dental dysplasia is also divided
into
 Anterior component
 Posterior component

a. Anterior maxillary dental height ( 1-NF ):
Perpendicular line dropped from incisal edge of
maxillary central incisor to NF.
b. Anterior mandibular dental height (1 - MP) :
Perpendicular line dropped from incisal edge of
mandible central incisor to MP.
These two measurements define how far the incisors
have erupted in relation to NF and MP respectively.
Anterior component is subdivided into

Posterior component
Posterior maxillary dental height : Perpendicular line
through maxillary 1st molar mesiobuccal cusp tip to
NF
Post mandibular dental height : Perpendicular line
through mandibular 1st molar mesiobuccal cusp tip to
MP.

IV. MAXILLARY LENGTH
Distance from PNS
– ANS that is projected on
a line parallel to the HP.
This measurement along
with the N-ANS and PNS
– N gives a quantitative
description of the maxilla
in the skull complex.

V. MANDIBULAR LENGTH
Ar - Go : Length of
Mandibular ramus
Go - Pg : Length of
Mandibular body
Ar - Go - Gn Angle : Gonial
angle that represents the
relationship between
ramal plane and MP.
B - Pg : Distance from B
point to line perpendicular to
MP through Pg describes chin
prominence.

These measurements are helpful in the diagnosis of
variations in ramus height, that effect open bite or
deep bite problems, increased or diminished
mandibular body length, acute or obtuse Go angles
that also contribute to skeletal open or closed bite, and
finally, as an assessment of chin prominence.

VI. DENTAL
Here, the teeth has
to relate to each other
through a common
plane, such as occlusal
plane (OP) or to a plane
in each jaw , the MP, or
the NF plane.

OP
Line drawn from the buccal groove of both 1 st
permanent molars through a point 1 mm apical of the
incisal edge of the central incisor in each respective
arch.
OP ANGLE
Is the angle formed between this plane and HP. If the
teeth over lap anteriorly to produce an overbite, the
OP can be drawn as a single line.www.indiandentalacademy.com

INCREASED OP- HP
 Skeletal open bite
 Lip incompetence
 Increased facial height
 Retrognathia
 Increased MP angle
DECREASED OP- HP
 Deep bite
 Decreased facial height
 Lip redundancy

AB – OP
Constructed by dropping a perpendicular line to OP
from points A and B, respectively, and than
measuring the distance between these two linear
intersections. If A- B distance is large with point B
projected posteriorly to A, mandibular denture – base
discrepancy that predisposes to a class II occlusion is
present.

ANGULATION
1 – NF (angle) : Line drawn from incisal edge of
central incisor through the tip of the root to the point
of inter section with NF
1 – MP (angle) : Line drawn from incisal edge of
central incisor through the tip of the root to the point
of intersection with MP.
These angulations determine the procumbency or
recumbency of the incisors and are vital in assessing
long term stability of the dentition.

NORMAL VALUES

SOFT TISSUE ANALYSIS
American journal of orthodontics
1958,1959,1967
The soft tissue covering the teeth and bone is
highly variable in it’s thickness and this variation
may be greater than the variation found in hard
tissues. So the treatment planning for the
patient who require orthognathic surgery should
also include the soft tissue analysis. This
following analysis is given by Harry.L.Legan &
Charles Burstone.www.indiandentalacademy.com

Sample:
40 young caucasians
15 male
25 female
Mean age – 23.8 years and profiles with acceptable
faces as determined from frontal and lateral
photographs by a panel of artists from the HERRON
school of art

Method:
Lateral cephalograms with the FHP parallel to floor, teeth in CO and the
lips lightly closed
Nasal floor (X), the line connecting ANS and PNS was selected as
reference plane.
Integumental landmarks were
Glabella (G) = The most prominent anterior point in the midsagittal
plane of the forehead
Subnasale (Sn ) = The point at which the columella (nasal septum)
merges with the upper lip in the midsagittal plane.
Superior labial
sulcus (SLS) = The point of greatest concavity in the midline
of the upper lip between subnasale and Labrale
superius.
Labrale
superius (Ls) = A point indicating the mucocutaneous border of the
upper lip. The most anterior point of the upper lip
(usually)www.indiandentalacademy.com

Stomion superius
(Stms) = The lower most point on the vermilion
of the upper lip.
Stomion inferius
(Stmi) = the uppermost point on the vermilion of
the lower lip.
Labrale inferius
(Li) = The median point in the lower margin
of the lower membranous lip.
Inferior labial sulcus
(ILS) = the point of greatest concavity in the
midline of the lower lip between labrale
inferius and soft-tissue pogonion. Also
known as labiomental sulcus(SI).

• Columella Point (Cm) – The most anterior point on the
columella of the nose.
•
• Cervical Point (C) The innermost point between the
submental area & the neck located in the intersection of
the lines drawn tangent to the neck and submental
areas.
•
• Gnathion (Gn) - This is the constructed point in the
intersection of 2 lines – Subnasale to pogonion and
cervical point to Gnathion

• FACIAL CONVEXITY ANGLE:-
  This is the angle formed between the G-Sn to
Sn-Pog line.
  The mean value is 12 degrees. Value is positive
if G-Sn line is anterior to Sn-Pog line Positive
value indicates Class II skeletal or dental
relationship & negative value indicates class III
relationship

MAXILLARY & MANDIBULAR PROGNATHISM:-
 A line perpendicular to the horizontal plane is
dropped from Glabella & relations of maxilla and
mandible are related to this line.
The distance from Sn to this line gives the amount of
mandibular excess or deficiency. Negative value
indicates mandibular retrusion and positive value
indicates mandibular procumbency. The mean
value is zero.

LOWER FACE THROAT ANGLE
This is the angle formed between Sn to Gn and Gn to C.
The mean value is 100 degrees. Decrease in the value
indicates prominent chin.
VERTICAL HEIGHT RATIO
The ratio of the distance sn to Gn and C to Gn is normally 1:1.2.
If the ratio becomes much larger than one, patient has relatively
short neck & the anterior projection of chin probably should not
be reduced.
NASO LABIAL ANGLE
This is the angle formed between Cm to Sn and Sn to Ls.
The mean value is 102 degrees. Increase in value indicates
maxillary advancement is necessary. Decreases value
indicates surgical retraction of maxilla is necessary

MENTO LABIAL SULCUS:-
This is the measurement from Sm to Li-Pog line. The average
value is 4 mm.
UPPER & LOWER LIP PROTRUSION:-
This is evaluated by drawing a line from Sn to Pog.
Ls to Sn-Pog line gives the amount of upper lip protrusion. The
mean value should be 3 mm.
Li to Sn-Pog line will give the amount of lower lip protrusion.
The mean value is 2mm.

VERTICAL LIP-CHIN RATIO:-
This is the ratio of Sn-Sts and Sti-M. Mean value is 4mm.
MAXILLARY INCISOR EXPOSURE:-
This is measured from tip of the maxillary incisors to Sts. The
mean value is 2mm.
INTERLABIAL GAP:-
This the distance from Sts to Sti. The mean value is 2mm.

Summary of soft tissue
analysis

CONCLUSION
A thorough knowledge about Burstone analysis will
definitely help the orthodontist and the maxillofacial
surgeon in successfully treating orthognathic surgery
patients and in establishing an esthetic, harmonious
and stable relationship of the cranial base, jaws and
teeth.

REFERENCES:
 Charles Burstone - Journal of oral surgery - vol:36
April 1979
Integumental profile analysis – A.J.O 1967
 Orthodontic cephalometry – Athanasios E athanasiou
 cephalometric radiography – Thomas rakosi
 Radiographic cephalometry – Alex Jacobson

Burstone

Recommended

Recommended

More Related Content

What's hot

What's hot (20)

Similar to Burstone

Similar to Burstone (20)

More from Indian dental academy

More from Indian dental academy (20)

Recently uploaded

Recently uploaded (20)

Burstone