Orthodontic Diagnosis

Changing concepts of diagnosis
Traditional approach. (Edward H Angle)
Rational approach. (Calvin Case, Milo Hellman)
Overall diagnosis. Moorrees, Gron, Proffit)

‘Diagnosis in orthodontics requires the synthesis of
manifold factors into a discrete list of problems each
defined so clearly that the treatment alternatives
become evident’.
Dr. Kyaw Thein

‘Diagnosis is the process, which involves the
collection of an adequate data base of information about the
patient and the distillation from that data base, of a
comprehensive but clearly stated precise list of the patient’s
problems’.

The Diagnostic Process.
History taking
(Questionnaire,
Interview)
Clinical
examination
Analysis of
Diagnostic
records
Data base Problem list
Diagnosis
Pathologic
diagnosis
Classification
Collection of data. Synthesis of diagnosis
Orthodontic
diagnosis

Collection of data.
The information about the patient derives from three
main sources.
Questionnaire or interview.
Clinical examination.
Analysis of diagnostic records.

HISTORY TAKING
QUESSIONAIRE OR INTERVIEW.

History taking. (Questionnaire or interview)
This process can be done by direct interviewing with
the patient or parent or with the use of booklets. Each has it’s
own advantages and disadvantages.
The objective is to gather information about the –
patient’s chief complaint/s. (main concern)
past medical and dental history.
physical growth status.
motivation, expectations and other social
and socio-behavioral factors.

Chief complaint/s.
To state the reasons for taking orthodontic treatment in
terms of patient’s own words.
Mostly, the patients are concern about the impaired
dentofacial aesthetic secondary to alignment and occlusion
of teeth which in some patients lead to psychosocial
problems. The other less common complaints are functional
and developmental problems.
The dentist should remain in a passive role. He should
not assume that aesthetics is the patient’s major concern
just because the teeth are unaesthetic nor should focus on
the functional implications because he thinks it is important.
If the chief complaints are more than one, prioritize
according to the patient’s own concern.

Medical and dental history.
A careful medical and dental history is needed –
- to provide a proper background for understanding the.
patient’s overall situatuon
- to evaluate specific orthodontically related medical and
dental conditions (medical and dental conditions influencing
diagnosis and treatment planning.)
The history should include –
Trauma to the teeth and jaws especially in patients with
facial asymmetry and severe malocclusion.
Long term medication of any type for chronic medical
problems. Eg. Cardiac diseases, rheumatic disorders ,
diabetes, epilepsy, hepatitis etc.
Drug allergy : eg- penicillin.

Physical growth status.
Evaluation of physical growth is an important aspect that
should be explored during history taking. Rapid growth during
adolescence facilitate significant tooth movement and growth
modification treatment.
Information about the growth status of a child should be
explored to determine whether the child has reached the peak
growth.
-Asking questions and assessing the growth chart to
locate the child’s position on the growth chart.
-Observing the stage of secondary sex characteristics to
predict peak growth.
Assessing the hand-wrist radiographs to determine
skeletal maturity.

Social and behavioral history.
Social and behavioral history should explore to judge
the followings.
Motivation
Cooperation
Expectation

Motivation
Motivation can be internal ie comes from within the
individual and is based on his or her own assessment of the
situation and desire for treatment.
Motivation can also be external by pressure from
other individuals as parent or friends.
It is important for a patient to have a component of
internal motivation or persuade the patient to become
motivated.
The cooperation is likely to be much better if the child
genuinely wants treatment for himself or herself rather than
just pleasing the parent.

Cooperation.
Patient cooperation is related with motivation and is
likely to be a problem in child than adult.
Cooperation is generally poor in in children with external
motivation. Persuasion and explanation about the treatment is
needed so that the child understands that the treatment is
being done for him rather than to him.
Cooperation is likely to be a problem in resentful and
rebellious adolescence especially with ineffective parents.
Sometimes parents need to be explained about the problem to
help them appreciate the treatment.

Expectation
Expectation from the outcome of treatment should be
explored carefully with adults, especially those with primarily
aesthetic problems and minor irregularity.
Resentment for orthodontic treatment could arise if the
treatment outcome could not meet the patient’s expectation.

Clinical examination.
Consistent and systematic approach to clinical
examination is required so that no important points would be left
out.
General oral and medical examination.
Specific orthodontic clinical examination.

General oral and medical examination

To identify and diagnose any pathologic conditions
not directly related with the patient’s orthodontic problems.
These pathologic conditions should be controlled or
treated before starting orthodontic treatment or need to
consider during treatment planning.

Examination of the hard and soft tissues eg condition
of teeth, periodontium, oral mucosa, caries activity etc.
Teeth and alveolar bone
Count the teeth present in the mouth to ensure the
number and type (deciduous or mixed) of teeth, missing
teeth, supernumerary teeth.
Examine and assess the quality of teeth eg, heavily
filled teeth, endodontically treated tooth, oriental premolar,
impacted teeth etc
Palpate the alveolar bone to detect the bulging if
missing or supernumerary teeth is suspected.

Periodontal disease
Identify active periodontal disease and mucogingival
problems.
eg gum recession, fenestrations and dehiscence.
Ease of bleeding on probing along the gingival sulcus
indicates active periodontal disease. Gingival hyperplasia,
juvenile periodontitis and juvenile diabetes should be
checked.
Severe gum recessions are usually associated with the
buccally erupted canine, labially displaced lower incisors and
in tooth with traumatic occlusion.

Oral mucosa
Check the oral mucosa for diseases like recurrent
aphthous ulcers, indentations in the cheek mucosa along
the occlusal line.
Feel the tautness or flaccidity of the lip and cheek as
this determine the position of teeth.

General medical conditions
Conditions like diabetes, SBE, rheumatoid arthritis,
epilepsy etc, should also be asked and clinical signs
suggestive of these conditions are checked during clinical
examination.
Evidence of trauma to the head and TMJ region, motor
neurone diseases and spastic muscle diseases affecting facial
muscles should be checked as they influence the
orthodontically treated tooth position and treatment planning.

Specific orthodontic clinical examination

Specific orthodontic clinical examination
Goals of orthodontic clinical examination
 To document and evaluate facial, occlusal and
functional characteristics
 To decide which diagnostic records are required.

Facial Characteristics
 Proportionality of the face, size, shape and position
of the eye, nose and mouth.
 The relationship of the maxilla, mandible and cranial
base in all three planes of space.
 The soft tissues enveloping the underlying skeletal
structures, including facial muscles, lip and tongue.
 To achieve these information extraoral examination
of face from the front (front view) as well as from the side
(profile view) is required.

Front view.
Proportionality of face. (Facial aesthetics)
In orthodontics facial aesthetics is judged by
proportionality of face. Proportionate face is aesthetically
acceptable if not beauty at all.
Height and width of the face
The proportionate relationship of the height and width of
the face (facial index) is evaluated by looking at a face in
general rather than its detail.
Categorize the face as long face, short face, oval face,
square face, tapering etc.
The ratio of the height and width (facial index) is more
important than the absolute values. Long lower face height may
not appear as too long depending upon its width. Treatment
should not alter the ratio in wrong direction.

Width of the eyes, nose and mouth
The width of the mouth should equal to the distance
between the vertical lines drawn through pupil of the eyes.
The level of mouth should be located at the junction of
upper and middle third of the lower third of the face.
The width of the nose should be about the distance
between the vertical lines drawn through the inner canthus of
the eyes.
The width of each eye should be about the distance
between the inner canthus and outer canthus lines.
Extreme variation in width suggest congenital
syndromes.

Vertical thirds
Face can be divided into three equal parts vertically.
From the hair-line to the midpoint between the eyebrow.
From this point to the junction of the lip and nose and from the
junction of the lip and nose to the lower border of the chin.

If these parts are equal the face is regarded as
proportionate.
Important to note which part is excessively long or
short particularly the middle and the lower facial thirds
and predict the occlusion that would likely to associate
with it intraorally.
Long lower facial thirds are usually associated with
anterior openbite and short lower facial thirds are likely to
associate deep bite.

Equal vertical thirds
Occlusal features

Vertical thirds
Occlusion in patient with reduced lower
facial third

Long lower facial third
Occlusal features

Sagittal fifths.
Proportionate face can be divided into five equal parts
sagittally or longitudinally.
Vertical lines passing through the inner canthus and
outer canthus of eyes. Vertical lines from the outer canthus to
the lateral margin of the face.
Observe which parts is excessively wide or narrow. Most
congenital syndromes are associated with the disproportionate
face.
Eg, hypertelorism associated with hypoplastic mid-face
is suggested of crouzon syndrome.

Asymmetry of face.
A small degree of bilateral asymmetry is present in all
individuals. (normal asymmetry)
However, severe asymmetry should be noted and the
cause of asymmetry should be looked for.
Eg, developmental, specific pathology, dental crowding and
mandibular displacement.
Face may be asymmetric due to skeletal (skeletal
asymmetry) or dental (dental asymmetry).

Skeletal asymmetry may be the result of variation in growth
and development or other pathologic conditions or trauma.
Most commonly dental asymmetry is the result of narrow
maxilla or severe crowding. The asymmetry is due to the
mandibular deviation secondary to premature occlusal
contact.

Clinical differentiation of skeletal from dental asymmetry
-Check the patient at rest position for asymmetry.
-Ask the patient to close from rest to occlusal position
slowly and observe the mandibular deviation.
-If asymmetry is present in both at rest and occlusal
position the cause is skeletal.
-If asymmetry occurs only when the jaw close to occlusal
position the cause is dental.
-Since the treatment planning is different between the
two, differentiation between the skeletal and dental
asymmetry is important.

Dental asymmetry.
 The mandible may be displaced to the right or left
due to premature occlusal contact secondary to
crowding or narrow maxilla.
 In narrow maxilla the mandible is displaced to
either side, into unilateral crossbite position to
achieve maximum intercuspation.
 However, in extreme narrowness of the maxilla,
the mandible directly closes into bilateral crossbite
position without lateral displacement.

Midlines
-Check whether the mid-facial line is coincide with the
dental midlines.
-Check whether the upper and lower dental midlines are
coincide.
-Centre line should be measured by placing a ruler down
the patient’s facial midline and measuring how far away
from this the center lines deviate.
The amount of deviation should be recorded.

Centric occlusion(CO) and Centric relation(CR) discrepancy.
• The mandible is supported at the front by the occlusion of
teeth and at the back by the mandibular condyles in its glenoid
fossa.
• Maximum function is obtained when the anterior vertical
stop provided by the teeth and the posterior vertical stop provided
by the joint are in harmony.
• If the mandible is laterally displaced, the joints would not be
in the centric relation position, eventhough the teeth were in the
maximum intercuspation.
• Maximum intercuspation is achieved, with mandibular
displacement, at the expense of centric relation position.
• Treatment objectives and planning should be made with the
mandible at CR position.

Dental base relationship
• The maxillary and mandibular basal bone greatly
determine the position of the upper and lower teeth and affects
the final occlusion.
• The examination of the dental base relation should be
carried out in sagittal, vertical and transverse planes.
• The anteroposterior relationship of the maxillary and
mandibular basal bones or the relationship of the maxillary and
mandibular basal bone in sagittal plane is called “skeletal
pattern”.

Profile view
 Assessment of anteroposterior relationship of the maxilla
and mandible. (Skeletal pattern)
 To establish whether the jaws are proportionately positioned
in the anteroposterior plane of space.
 The anteroposterior relation of the maxilla and the mandible
is usually defined by the ‘skeletal pattern’ as determined
from the profile examination.

Clinical methods for assessing the skeletal pattern.
Facial profile examination
Place the patient in natural head position.
- Ask the patient to look straight ahead and relax.
- In this position the Frankfort horizontal plane is parallel to the
floor.
Drop two lines.
1- One extending from the bridge of the nose (junction of the
frontal and nasal bone) to the base of the upper lip. (junction
of the lip and nose)
2- The second line extending from the junction of the lip and
nose to the most anterior point on the chin.

Skeletal pattern I: the two lines forms a one straight line resulting
a straight facial profile.
Skeletal pattern II: the two lines meet at an angle resulting a
convex facial profile.
Skeletal pattern III: the two lines meet at an angle resulting a
concave facial profile.
Skeletal ISkeletal II Skeletal III

Skeletal pattern I. (Straight facial profile)
FHP

Skeletal pattern III. (Concave facial profile.)
FHP

Skeletal pattern II. (Convex facial profile.
FHP

The other methods of determining the skeletal pattern
• Observing the true vertical lines drawn through the depth of
the concavity at upper and lower lips. (approximately at the
anterior limit of the maxillary and mandibular basal bones, ‘A’ point
and ‘B’ point).
• The maxillary base should
lie about 2 to 3 mm anterior to the
mandibular base in skeletal pattern I.
• The maxillary base lie more
than 2 to 3 mm anterior to
mandibular base, skeletal pattern II
and if posterior skeletal pattern III.

Two finger method. The first finger of the right hand
palpates the alveolar outline in
the middle of the upper jaw as
high as in the reflection of the
mucosa as possible.
The second finger palpates the
alveolar outline at the mucosal
reflection of the lower jaw.
Class I-the first finger slightly
anterior to the second finger.
Class II-more than slightly
anterior.
Class III-the first finger is
posterior to the second finger.

Vertical relation
Examination of face in vertical plane can also be
examined from the profile view.

• Facial height is usually expressed as a ratio, relative to the total
facial height. The lower facial height is approximately about 55%
of total facial height.
• Determination of posterior facial height from clinical examination
is difficult even though it is better to include when considering the
anterior facial height.

Mandibular form and mandibular plane angle
 Mandibular form or shape of the mandible, curvature of
the lingula varies from person to person.
 Deep antegonial notch and less curvature of lingula is
usually seen in persons with long face and flat lower
border of mandible and acute curvature of lingula in
short face persons.

Mandibular plane angle
 Mandiblar plane, in clinical examination, is the imaginary plane drawn along
the lower border of the mandible.
 Frankfurt horizontal plane is an imaginary line drawn through the lowermost
point on the orbital rim and the uppermost point on the external auditory
meatus.
 Mandibular plane angle is the angle formed by the intersection of the
mandibular plane and the Frankfurt horizontal plane.
 The other horizontal reference lines for determination of mandibular plane
angle are Sella-Nasion plane, palatal plane , occlusal plane, and true
horizontal plane.

The average mandibular plane angle is (27 + 5H H ) .
Above ( ) is regarded as high angle and
below ( ) is regarded as low and angle.

Clinical assessment of mandibular plane angle.
Clinically mandibular plane angle can be assessed by the
imaginary line drawn posteriorly along the lower border of
mandible. Also draw the FHP posteriorly.
If the two lines meet at the occiput - average mandible plane
angle.
If it meet inside the skull - high angle mandible
If it meet outside the skull - low angle mandible
High angle mandible is usually
associated with long face , and
low angle mandible with short face.

Examination of the facial soft tissues.

Lips
Lip contour
 Contour of lip can be described as average, everted or
thin lip.
 Lips are everted if curled up and exposed the red margin
(muco-cutaneous junction).
 Thin lips if they are less prominent and rather vertical with
no obvious outward curve at the red margin.
 The average lies in between.

Lip with average contour-
- very slide amount of mucosa is visible beyond the vermilion
margin of the lips.
- Inclination of the lower incisors is usually normal.
Vertical lips-
- The vermilion border is not visible.
- Both upper and lower incisors tend to be retroclined.
Everted lips-
- A large area of mucosa is visible beyond the vermilion margin .
- Both upper and lower teeth tend to be proclined.

Lips
Lip competency
 Defined as an ability to seal the lips without excessive strain.
Up to 4 mm of lip separation at rest may be regarded as normal.
 Lips should be competent in a well balance face. ( that is , the upper
and lower lip could bring together in lightly contact with each other
without conscious efforts)
 Incompetent lip often manifest hyperactivity of the mentalis muscles
during swallowing to achieve lip seal.
Clinically appear as dimpling of soft tissues over the chin and flattening
out of the submental fold.

Lip incompetence can be due to :
1- short resting lip length eg – short upper lip
2- pioclined upper incisors
3- an increased anterior lower facial height so that the lips are
unable to contact with each other.
4- a large anterio-posterior skeletal discrepancy
 The upper and lower lip may have to bring forward over the
incisors with the action of the lip muscles (or)
 In severe cases , the tongue may have to protrude forward
between the upper and lower incisors to contact with the lips to
achieve anterior oral seal during swallowing.

Lip line
 The relationship of the upper border of the lower lip to the labial
surface of the upper incisors is referred to as lip line.
 It is applied only to the relationship of the lower lip to upper
( central ) incisor.
 Ideally , at rest , the lower lip covers between a third and half of
of the labial surface of the upper central incisors.
Normal lip line - When the lower lip meets the upper lip in front of
the upper incisors at the junction between middle and incisor one
third of the upper incisors.

The level of upper lip line to upper incisors
 The margin of an upper lip should be located at the junction of
the incisal and middle third of the upper incisors.
 The facial esthetics is usually compromised if the margin of the
upper lip is located high up on the attached gingival, exposing
the whole length of upper incisors, at rest or during smiling.
(gummy smile)
 The causes may be due to :
- proclined upper incisors ,
- short upper lip.

Gumming smile due to short upper lip

 Lip line could be high or low in relation to the upper incisors.
eg – In Class II Div 2 cases lip may be competent with a high lip line.
In extreme Class II Div cases, upper incisor crown may be fully covered by
the lower lip.
eg – In Class II Div 1 cases , lip may be low lip line .
 Lip line is also determined by both anterior-posterior and
vertical skeletal discrepancies.
 Lip line will be a useful clinical reference to the clinician to just
the stability of the corrected incisor relationship .

The level of lower lip to upper incisors
• The margin of lower lip should cover the incisal thirds of the upper
incisors.
• The position of the lip may vary depending upon the position of the
upper incisors.
• The lower lip may be trapped behind the upper incisors as in severe
class II division 1. The upper incisors may be biting into the lower lip
or the whole length of upper incisors may be covered by the lower lip.

Teeth are in soft tissue
balance between the
tongue and the lip.

These diagrams show how partial reduction of the overjet
does not allow the lip to cover the upper incisors .
The upper incisors are then quite likely to return to their pre-
treatment position .

The protrusion or retrusion of lip can be assessed by the
followings.
Holdaway line- drawn from the most anterior point on the chin
across the anterior point of the upper lip and extending across the
nose.
The outline of the nose anterior
to this line and the curve of the
upper lip posterior to it should
form a symmetric ‘S’ curve.
Esthetic line (‘E’ line)- drawn
from the most anterior point
on the chin and nose.
The lips should just touch the ‘E’ line.

Soft tissue in function
• In addition to the soft tissue in rest position, the position and
relation of soft tissue during function should be assessed.
• Swallowing behavior like tongue thrust swallowing , forward
tongue position , lip biting , etc should be checked.
• In patients with TMJ problems the muscles of mastication
should be palpated.

Intraoral examination
 A careful and systematic intraoral clinical examination is
required to include all the important information
regarding the patient’s complaint.
- General examination of the mouth
- Specific orthodontic examination.

General examination of the mouth
Provide data for the pathologic diagnosis, a conditions
which need to be controlled or treated before starting the
orthodontic treatment.
Count the teeth - Not only the number of teeth are counted but
also the type of teeth (deciduous or permanent), size and shape
anomalies, caries.
Examination of periodontal tissues.
Examination of the oral mucosa and tongue.
Examination of the temporomandibular joint – Important in
patients with history of TMJ dysfunction, CO, CR discrepancy and
in patients with facial asymmetry.

Specific orthodontic examination
Examination of the upper arch
Examination of the lower arch
Examination of the upper and
lower arch at occlusion
Alignment problem
Dentitional problem
Space problem
Dentoskeletal relation
Dentoalveolar relation

Specific orthodontic examination
Examination of the upper arch and lower arch.
Alignment problems - any tooth deviating from the line of
occlusion eg. Buccally erupted canine, palatally instanding lateral
incisors etc.
Dentitional problems – any tooth crowns that is rotated,
tipped mesially or distally and has size and shape anomalies.
Space problems – Crowding manifested as actual crowding
in the arch or procline incisors. Spacing manifested as localized or
generalized spacing.

Examination of the upper and lower arch at occlusion
Maxillary and mandibular dentoalveolar relation.
Examine the upper and lower arch with the teeth at centric
occlusion in anteroposterior plane.
Molar relation – defined as Angle’s first permanent molar
relation: Angle’s class I, class II or class III and state half cusp
class, full class, left side, right side or both sides.
Canine relation – defined as canine class I, class II or class
III and state half cusp, full cusp, left side, right side or both sides.
Incisor relation – defined according to British Standard
Incisor Classification as class I, class II or class III incisor relation.
State the extent of overjet qualitatively or quantitatively. Eg.
Increased overjet, reduced overjet, edge to edge etc.

Vertical plane
Overbite relation of maxillary and mandibular anterior and
posterior teeth. Described as average, reduced and deep
overbite. Complete overbite if the lower incisor edges touch the
cingulum of upper incisors or palatal mucosa and incomplete if fail
to make contact with uppers.
Edge to edge bite if upper and lower incisor edges are
contact with each other.
Open bite if there is lack of vertical overlapping between
the upper and lower incisors. It is described as extending from
which tooth to tooth and the extent of open bite is expressed in
millimeter at widest area.

Lateral plane
Examine the relation of maxillary and mandibular teeth in
lateral (transverse) plane of space.
In normal relation, the maxillary teeth overlaps the
mandibular teeth on the facial side.
Defined as cross bite if this relation is reversed.
Eg. Anterior cross bite, posterior cross bite. Usually named after
the direction of displacement of the involved tooth. Eg. Maxillary
palatal cross bite. (Maxillary teeth displaced palatally), Mandibular
buccal cross bite.
Cross bite is commonly seen in patients with facial
asymmetry and narrow maxilla. Identify whether the cross bite is
skeletal or dental.

Clinical distinction of skeletal and dental cross bite
 Check the face for asymmetry in rest position.
 Ask the patient to close from rest to centric occlusal
position.
 If asymmetry is seen in both rest and centric occlusal
position – skeletal asymmetry.
 If asymmetry is seen only when closure into centric
occlusion – dental asymmetry.

Dento-skeletal relation
The relationship of long axis of the upper and lower incisors
to the respective reference planes – FHP, palatal plane, sella-
nasion plane and mandibular plane.
Clinically may be described as proclined or retroclined
incisors relative to basal bone.

Analysis of Diagnostic Records

Reasons for taking diagnostic records
 To aid in diagnosis and treatment planning by adding
information to the clinical examination data

The most commonly used diagnostic records are –
Study models
Photographs
Radiographs
Analysis –
Model analysis
Space analysis
Tooth size analysis
Cephalometric analysis

Study Models (Dental casts)
Orthodontic study models must record the teeth and
the alveolar bone. Therefore during impression taking the
maximum extension of material into the vestibule is important.
The models must be properly trimmed so that the
bases of the upper and lower models are flushed and
perpendicular to the midpalatal raphae.
In patients with TMJ problems and CO-CR
discrepancy, the occlusion of teeth should be recorded with a
wax or silicone rubber and mounted in an articulator
Models may be taken before starting orthodontic
treatment, during treatment and at the end of the treatment.

Models are needed for –
1- Pre-orthodontic records.
2- To use as a reference and for medico-legal
purposes.
3- To assess and record arch form , occlusal curve.
4- Evaluation of occlusion and allow analysis for
diagnosis.eg-space analysis , tooth size analysis.
5- Recording and assessment of treatment change.
6- Discussion of treatment plan with patient
7- Post treatment records.
8- Construction of appliances.

Photographs
1- Provide records for diagnosis, therapeutic and medico-
legal purposes.
2- Allow examination of face and teeth at times
convenient for the dentist.
3- As a media for discussion of treatment plan with
patient.
4- Recording and evaluating treatment change.

Photographs
Extraoral and intraoral photographs-
Extraoral photographs -
Facial photographs – front view.
Facial photographs – side view.
Intraoral photographs -
occlusal view upper arch
occlusal view lower arch
front view with teeth at occlusion
side view with teeth at occlusion
side view with teeth at occlusion.
Additional photographs may be taken if needed.

Radiographs
Commonly used radiographs –
Orthopantomographic X-ray (OPG)
Lateral and posteroanterior cephalometric X-ray
Intra-oral X-rays- standard occlusal X-ray
periapical X-ray
Hand-wrist radiographs
Less commonly used radiographs –
TMJ X-rays
MRI, CT scan

Model analysis
Maxillary cast
Symmetry of the arch and dentition.
Intra-arch problems-
- spaced problems- crowding, spacing.
- alignment problems- any tooth deviating from
the line of occlusion.
- dentitional problems- rotation, tipping,
ectopically erupted tooth, peg laterals etc.
Mandibular cast
As above.

Maxillary and mandibular arch at occlusion
Anterposterior plane-
- Molar relation- Angle’s classification class I, II, III
- Canine relation- class I, II, III
- Incisor relation- overjet measured in millimeter.
Vertical plane-
- overbite- measured in millimeter.
- openbite
Transverse plane-
- crossbite- eg maxillary lingual crossbite,
mandibular buccal crossbite.

Spaced analysis
Comparison between the amount of space available for the
alignment of the teeth in the dental arch and the amount of space
require to align them properly.
The objective of space analysis is to quantify the imbalance
between the tooth tissue and alveolar bone or dentoalveolar
discrepancy and to establish the deficiency of space- crowding, or
excess of space- spacing.
Space
available
Space
required
Compare
Space excess
OK
Space deficiency

space analysis can be done either :
1- directly on the dental casts or
2- by a computer algorithm after appropriate digitization of the
arch and tooth dimensions.
Space available
It is the circumferential length of the alveolar arch or an
existing space in the alveolar arch.

Measured by-
(1) dividing the arch into straight line segments, from the mesial
contact point of first permanent molar on one side to the
mesial contact point of the first permanent molar to the other ,
over the contact points of posterior and incisal edge of anterior,
and adding these straight lines approximations.

(2) by adapting the brass wire along the alveolar arch –
passing over the imagined correct position of the canine,
the center of the occlusal surfaces of the premolars and
the incisal edge of the most labial of the incisors.
- The adaptation of the brass
wire should comprise a smooth
arc , free from kinks , and
should simulate the desire
arch form.
- The brass wire is then straightened and the length
measured with a millimeter ruler.

Space required
 It is the space required for the perfect alignment of teeth in the
dental arch at correct position over the basal bone and approximal
relation at each interdental contact point.
 Measured by summing the greatest mesiodistal diameter of all
teeth mesial to first permanent molar. (measured from mesial to
distal contact points of each tooth anterior to first permanent
molar.)

Dento-alveolar discrepancy
 It is obtained by subtracting the amount of space available and
space required.
 Arch perimeter deficiency or crowding or insufficient space for
the perfect alignment of teeth in the dental arch would occur if the
sum of the widths of the permanent teeth is greater than the
amount of space available.
 If available space is larger than the space required (excess
space) gaps between the teeth or spacing would be expected.

Space analysis carried out in this way is correct only if-
 the incisors are correctly positioned over the basal bone ,
neither proclined nor retroclined.
 the curve of Spee is not excessively curved.
 the space available will not change because of growth.
 all the teeth are present and reasonably normal in size.
Compensation for incisor position and curve of Spee
 Add 2mm to the discrepancy for every 1mm overjet
correction.
 Measure the curve of Spee and add or substract the value
from the dentoalveolar discrepancy.

1st assumption
There is an interaction between crowding of the teeth and
protrusion or retrusion :
- if the incisors are positioned lingually (retruded ) , this
accentuates any crowding.
- If the incisors protruded , the potential crowding will be at
least partiolly alleviated.
2nd assumption
In a child with a well –proportioned face , there is little or no
tendency for the dentition to be displaced relative to the jaw
during growth , but the teeth often shift anteriorly or
posteriorly in a child with a jaw discrepancy.
For this reason , space analysis is less accurate and less
useful for children with skeletal problems.(Class II , Class III ,
long face , short face ) than in those with good facial
proportions.

- Even in children with well-proportioned face ,the position of the
permanent molars changes when primary molars are replaced
by the premolars.
- If space analysis is done in the mixed dentition , it is necessary
to adjust the space available measurement to reflect the shift in
molar position that can be anticipated.
3rd assumption
- Can be checked by clinically and radiographic examination ,
looking at the teeth as a set rather than as individual units .
- Anomalies in tooth size have significant implications for space in
the dental arches .

Mixed dentition space analysis (Estimating the size
of unerupted permanent teeth)
Space analysis in the mixed dentition requires estimation of
the unerupted permanent canine and premolars.
Methods 1.
Measurement of the teeth on radiographs 2.
Prediction methods: the size of the erupted lower permanent
incisors is used to predict the size of the unerupted
premolars and canine using predictability table or
the following formula.
( TANAKA AND JOHNSTON PREDICTION VALUES )
One half of the
mesiodistal width + 10.5mm For the estimated width of the
of the four lower mandibular canine and premolars
incisors in one quadrant
+ 11 mm For the estimated width of the
maxillary canine and premolars in
one quadrant.

Measurement of the teeth on radiographs.
 This requires an undistorted radiographic image (periapical films and
panoramic radiographs ) .
True width of primary molar True width of unerupted premolar
------------------------------------------- = --------------------------------------------------
Apparent width of primary molar Apparent width of unerupted premolar

Estimation from proportionality tables. (Moyers prediction tables)
-The mesiodistal width of the lower incisors is measured and this
number is used to predict the size of both the lower and upper
unerupted canines and premolars.
Combination of radiographic and prediction table methods.
- A graph developed by Staley and Kerber from lowa growth data
allows canine width to be read directly from the sum of incisor
and premolar widths.
- this method can be used only on the mandibular arch and
requires periapical radiographs.

Computer algorithms for space analysis
- Are bases on correlation of tooth sizes , and should be used
with caution if the radiographs show anything unusual (unless
the computer program allows for introduction of radiographic
information).
- Computer analysis is faster and easier , but its accuracy will
depend on how well the patient meets the assumptions that
underline its approach.

Tooth size analysis
 Used to analyse the relation between the individual tooth sizes of
maxillary and mandibular arches.
 The teeth in the maxillary and mandibular arches must be
proportional in size to achieve a good or an ideal occlusion.
 The disproportion among the tooth sizes of individual teeth is
defined as tooth size discrepancy.
 Tooth size analysis is used to analyse the size relation between the
individual teeth of maxillary and mandibular arches.

 An anomaly in the size of upper lateral incisors is the most common
cause , but variation in premolars or other teeth may be present .
 A quick check for anterior tooth size discrepancy can be done by
comparing the size of upper and lower lateral incisors.
- Unless the upper lateral incisors are larger , a discrepancy almost surely
exists.
 A quick check for posterior teeth size discrepancy is to compare the size of
the upper and lower second premolars , which should be about equal size.
 A tooth size discrepancy of less than 1.5 mm is rarely significant but larger
discrepancies create treatment problems and must be included in the
orthodontic problem list.

 Tooth size analysis or Bolton analysis is carried out by measuring the
mesiodistal width of each permanent tooth.
 A standard table is used to compare the summed total width of the
maxillary to the mandibular anterior teeth and the total width of all
upper to lower teeth, excluding second and third molars.
Tooth size relationships (Standard table)
Maxillary anterior Mandibular anterior Maxillary total Mandibular total
Sum of 3-3 Sum of 3-3 Sum of 6-6 Sum of 6-6
40 30.9 86 78.5
41 31.7 88 80.3
42 32.4 90 82.1

Bolton vs. Arch Length
 Comparison between two
arches
 Measurements needed:
 Mesiodistal tooth widths for
each arch
 Discrepancy may result in :
 arch length discrepancy
 abnormal overjet
 Class II or Class III occlusion
 Comparison within a single
arch
 Measurements needed:
 Mesiodistal tooth widths for
single arch
 Arch length for the same arch
 Discrepancy always results
in either:
 spacing
 crowding
Bolton Discrepancy Arch Length Discrepancy

If the upper teeth are larger relative to the lower :
1 - Excessive overjet & overbite or
2 - Crowded in anterior maxillary segment or
3 - Maxillary posterior teeth may be positioned in a distal
relationship
If the lower teeth are larger relative to the upper :
1 - Reduced overjet or end to end incisor relationship or reverse
overjet or
2 - Spacing between maxillary incisors or
3 - Maxillary posterior teeth in mesial relationship or
4 - mandibular incisor crowding and improper occlusion of
posterior teeth.

The amount of maxillary tooth material excess is calculated by
using the following formula:
Overall maxillary = Sum of _ Sum of mandibular 12 x 100
excess maxillary12 91.3
The amount of mandibular tooth material excess is calculated by
using the following formula :
Mandibular overall = Sum of _ Sum of maxillary 12 x 91.3
excess mandibular 12 100

The amount of mandibular anterior tooth material excess is
calculated by using the following formula :
Mandibular anterior = Sum of _ Sum of maxillary 6 x 77.2
Tooth material excess mandibular 6 100
The amount of maxillary anterior tooth material excess is
calculated by following formula :
Maxillary anterior = Sum of _ Sum of mandibular 6 x 100
tooth material excess maxillary 6 77.2

Tooth size ratio
Anterior tooth size ratio
The summed total of mandibular six anterior teeth is
divided by the summed total of maxillary six anterior teeth,
multiplied by 100 and the value is compared with the norms.
(74.5 – 80.4 %)
Posterior tooth size ratio
The summed total of mandibular 12 teeth is divided by
the sum total of maxillary 12 teeth, multiplied by 100 and the
value is compared with the norms.(87.5 – 94.8 %)

Sum of mand : 6
Anterior ratio = ------------------------ x 100
Sum of max : 6
(Range = 74.5 – 80.4) (Mean ratio = 77.2)
Sum of mand: 12
Overall ratio = -------------------------- x 100
Sum of max: 12
(Range = 87.5 -94.8) (Mean ratio = 91.3)

Craniometry
Measuring craniofacial dimensions on the dry skulls of
long dead individuals.
Cephalometry
Measuring craniofacial dimensions on the living
using cephalogram or skull radiographs.
Cephalometric radiography
The prodction of skull radiographs called
cephalogram, cephalometric X-ray, or ceph.
Commonly used ceph radiographs-
- lateral cephalometric X-ray.
- postero-anterior cephalometric X-ray.

 Assessment of cranio-facial structures forms
a part of orthodontic diagnosis.
 Craniometry can be said to be the forerunner
of cephalometry.
 Craniometry involved measurements of cranio
facial dimensions of skulls of dead persons.
 This method was not practical in living
individual due to soft tissue envelope that
made direct measurement difficult and far
reliable.

 Cephalometry was a modification of
anthropological studies and craniometry.
 PACINI in 1922 published the first paper
on cephalometry.
 But it was BROADENT(USA) and
HOFRATH(Germany) who introduced and
popularized in 1931.
 Clinical application of cephalometry was
introduced by DOWNS.
History

Bjork, 1951Thurow, 1951
Marcolis, 1940Waldo, 1938

 Lateral cephalogram; provides lateral
view of skull.
 Frontal cephalogram; provides
anteroposterior view of skull.
Types

Uses of cephalometry
Research- research on growth patterns in the
craniofacial complex.
Diagnosis- to evaluate dentofacial proportions and
clarify the anatomic basis for a
malocclusion.
Treatment monitoring- recognizing and evaluating
changes brought about by
orthodontic treatment.
Screening- as a screen for observing pathologic
changes.

Basic equipments for cephalometric radiography
- Source of X-rays
- Head holder or cephalostat or cephalometer
- Image recording system-
- films, screens and film processing
Source
Head holder
Image recording system

Source of X-rays (X-ray generators)
- Conventional dental X-ray machines.
(10 to 15 mA (milliamperes) , 70 kVp (peak kilovoltage)
- Dual purpose X-ray machines.
(for intraoral and ceph or ceph and panoramic radiographs)
- The exposure time is approximately 0.6 -1.2 seconds.

Cephalostat (head holder)
 It is the device used to position and stabilized the
patient’s head for cephalometric radiography.
 Basically it consists of two ear rods that moved
simultaneously or individually along the path of central
ray. (transmeatal axis). The device holds the head with
the central ray in the transmeatal axis.
 Cephalostat stabilized the patient’s head in horizontal
plane.
 Patient’s head is positioned with the Frankfort horizontal
plane or in natural head position and is fixed by the
device.

Image recording system
Films
 Films can vary in speed or sensitivity depending on the
crystal size and thickness of crystal layer.
 Fast speed (high), medium speed (par), slow speed (detail)
 The faster the film speed, the lesser the detail and the
shorter the exposure time.
 The slower the film speed, the sharper the image and the
longer the exposure time.
 Film size is usually 8 × 10 inch or 10 × 12 inch.

Screens (Intensifying screens)
 Screens are special sheets coated with crystals of a heavy
metals (high atomic number), usually calcium tungstate
crystals, that absorb x-rays more efficiently (than film)
and convert the energy into light. (by fluoresce of the
crystals).
 The visible light is then absorbed by light sensitive x-ray
film which is then processed to produce the radiograph.
 Therefore, the radiographic image is produced by the
screen-film combination. Screen-film system needs less
radiation to produce the radiographs than films used
alone.

Cassettes
 Cassettes are light tight boxes used to hold the screens
and film in intimate contact with each other. Springs,
clamps, felt backing and other devices are used to
maintain screen-film contact.
 Film is placed in the cassette and is sandwiched
between the two front and back screens.

Cassettes
Cassettes serve 3 important functions:
1. Protect film from exposure to light
2. Protect film from bending and
scratching during use.
3. Contain intensifying screens, keeps
film in close contact to screen during
exposure.

Radiographic factors
Patient-
 The patient’s head is positioned in FHP or in natural head
position.
 The head is stabilized in the cephalostat so that the central
ray is in transmeatal axis.
X-ray source -
 The x-ray source is positioned on the right side, at a distance
of 5 feet from the mid-sagittal plane of the patient.
 The primary beam or the central ray is directed through the
transmeatal axis of the patient.

Film-
-The film is placed perpendicular to the central ray of the
x-ray beam in both the horizontal and vertical planes.
-The midsagittal plane of the patient is plano-parallel with
the film.
-The patient to film distance varies but usually about
5 to 8 inches.

Film exposure
 Film speed.
 Tube (source) to film distance.
 Size of patient’s head and skeletal structure.
 Milliamperage. mA
 Kilovoltage peak. kVp

Cephalogram (Cephalometric x-ray)

Most commonly used ceph
landmarks
Cranial base landmarks
1.Orbitale (Or) -The lowest point on the inferior orbital
rim.

landmarks
1.Orbitale (Or) -The lowest point on the inferior orbital rim.
2. Porion (P) -The most superiorly positioned point
of the external auditory meatus.

landmarks
2. Porion (P) -The most superiorly positioned point of the external auditory
meatus.
3.Nasion (N) -The most anterior point on the
frontonasal suture in the midsagittal plane.

landmarks
meatus.
3.Nasion (N) -The most anterior point on the frontonasal suture in the
midsagittal plane.
4.Sella (S) -Geometric center of the pituitary fossa
(sella turciaca) located by visual inspection.

landmarks
meatus.
3.Nasion (N) -The most anterior point on the frontonasal suture in the
midsagittal plane.
4.Sella (S) -Geometric center of the pituitary fossa located by visual
inspection.
5.Basion (Ba) -The lowest point on the anterior rim
of the foramen magnum.

Landmarks on the maxilla
1. Pterygomaxillary fissure (Ptm) -Apex of the
teardrop shaped pterygomaxillary fissure.

1. Pterygomaxillary fissure (Ptm) -Apex of the teardrop shaped
pterygomaxillary fissure.
2. Anterior nasal spine (ANS) -Anterior tip of the
sharp bony process of the maxilla.

2. Anterior nasal spine (ANS)-Anterior tip of the sharp bony process of
the maxilla.
3. Posterior nasal spine (PNS) -The posterior tip
of the palatine bone constituting the hard palate

2. Anterior nasal spine (ANS)-Anterior tip of the sharp bony process of
the maxilla.
3. Posterior nasal spine (PNS) -The posterior tip of the palatine
bone constituting the hard palate
4. Point A -The most posterior point in the concavity
between the ANS and the maxillary alveolar
process.

Landmarks on the mandible
1. Point B -The most posterior point in the
concavity between the chin and mandibular alveolar
process.

1. Point B -The most posterior point in the concavity between the
chin and mandibular alveolar process.
2. Pogonion (Pog) -The most anterior point on the
chin.

2. Pogonion (Pog) -The most anterior point on the chin.
3. Menton (Me) -The lowest point on the
symphyseal shadow of the mandible.

3. Menton (Me) -The lowest point on the symphyseal shadow of the
mandible.
4. Gnathion (Gn) -The mid point between the
anterior (Pogonion) and inferior (Menton) points of
the bony chin.

mandible.
4. Gnathion (Gn) -The mid point between the anterior (Pogonion) and
inferior (Menton) points of the bony chin.
5. Gonion (Go) -A point on the curvature of the angle
of the mandible located by bisecting the angle formed by lines
tangent to the posterior ramus and the inferior border of the
mandible. The most posterior and inferior point on the angle of
the mandible.

mandible.
4. Gnathion (Gn) -The mid point between the anterior (Pogonion) and
inferior (Menton) points of the bony chin.
5. Gonion (Go) -A point on the curvature of the angle of the mandible
located by bisecting the angle formed by lines tangent to the posterior
ramus and the inferior border of the mandible. The most posterior and
inferior point on the angle of the mandible.
6. Articulare (Ar) -A point at the junction of the posterior border
of the ramus and the inferior border of the posterior cranial
base (occipital bone).

Commonly used horizontal reference lines
The Sella-Nasion line (SN) line -The line joining the Sella and
Nasion points. It represents the anteroposterior extent of the
anterior cranial base and serves as a reference line when
relating facial structures to the cranial base.
The Frankfort horizontal plane (FHP) -The line joining the
orbitale and the porion. It represents one of the horizontal
reference planes of the head.
The palatal plane (Pal) -The line joining the anterior nasal
spine (ANS) and the posterior nasal spine (PNS). It indicates the
positional tilt of the maxilla in space.

The mandibular plane (Mp plane) -The line tangent to the
inferior border of the symphysis outline and posteriorly tangent
to the inferior border of the mandible, posterior to the antegonial
notch.
By relating with the SN plane or FHP, it provides an assessment
of vertical proportion in the lower face.
The occlusal plane (Occ plane) -The plane drawn by bisecting
the incisor overbite (or openbite) and drawn over the distal
cusps of the most posterior teeth in occlusion.
The tilt of an occlusal plane indicates the extent of anterior and
posterior tooth eruption.
True vertical line -A line drawn on the tracing paper
perpendicular to true horizontal line or plumb line.

Cephalometric analysis
Lateral cephalogram allows-
-Skeletal assessment.
-Dental assessment.
-Soft tissue assessment.

Skeletal assessment
Analysis of the relation of the maxilla and the mandibular
basal bone to each other and to the cranial base.
The relation of the maxilla and the mandibular basal bone
to the cranial base

Cecil c. Steiner
 Cecil c. Steiner(1896-1989)
 One of Edward H.Angle’s first students
in 1921.
 He developed a form of cephalometric
analysis, presented in 1953,referred to
as the Steiner method of analysis.

Steiner’s analysis
-The plane of reference in Steiner’s analysis is Sella-
Nasion plane (S-N plane).
-Point ‘A’ and point ‘B’ are regarded as the anterior
limits of the maxilla and mandible apical bases.
-To determine whether the maxilla or the mandible is
positioned anteriorly or posteriorly relative to the cranial
base, the angle SNA and SNB is measured.

Steiner use SELLA to NASION line as a reference plane for his
analysis. This line represents the anterior cranial base.
Steiner highlighted difficulties in accurate location of the porion
point and its relative variation, which could be observed in
successive radigraphs.This in turn, affected the orientation of F-H
plane.
S and N points have another advantage of being located in the
mid sagittal plane of the head and move minimally with any any
deviation of head from true profile position. The cranial base
undergoes very little change after the age of 6-7 years.
SN plane substituted FH plane

•SNA -SNA indicates anteroposterior position of the maxilla
relative to cranial base.
• -The mean SNA reading is 82˚.
• -The SNA reading greater than 82˚ indicate forward
positioning of the maxilla.
• -The SNA reding lesser than 82˚ indicate backward or
recessive position of the maxilla.

•SNB -
• SNB indicates anteroposterior position of
the mandible relative to cranial base.
• -The mean SNB angle is 80˚.
• -The SNB reading greater than 80˚
suggest prognathic mandible.
• -The SNB reading lesser than 80˚
suggest retrognathic mandible.

The relation of the maxillary and mandibular basal bone
-The ANB angle or the difference between the SNA and
SNB readings, provides information on the relative position of
the jaws to each other.
-It indicates the general idea of the anteroposterior jaw
discrepancy of the maxilla to the mandibular apical bases.
-The mean reading is 2˚.

-The ANB reading greater than 2˚ indicates class II
skeletal tendency. The larger the figure the greater the
anteroposterior jaw discrepancy and the greater the difficulty
in correcting the malocclusion.
-The ANB reading lesser than 2˚ and reading below
zero, indicates class III skeletal tendency or that the mandible
is located ahead of the maxilla or

ANB = 2˚ ANB = 6˚ ANB = -7˚
Class I Class II Class III

 Wit’s Apprasal (Wit’s analysis)
 Done by Professor Alex Jacobson
 In University of Witwatersrand , Department
of Orthodontics

Wit’s Apprasal (WITS)
Drawing parpenticular line from point A and point B
respectively to the occlusal plane which is drawn through
the region of the overlapping cusps of the first premolars
and first molars
The points of contact on the occlusal plane from point A and
B are labeled AO and BO,respectively
AO_BO (for men) average = _1.0 mm
(for women) average= 0 mm
The greater the Wit’s reading deviation from _1 mm in men
and 0 mm in women, the greater the horizonal or
anteroposterior jaw disharmony.

The dental assessment
The reference planes for the dental assessment are the
Frankfort horizontal plane and the mandibular plane.
The Frankfort horizontal plane is line joining the inferior
border of the orbital rim (Or) and the superior border of the
external auditory meatus (Po).
The FHP is oriented horizontal for analysis.

The mandibular plane
The mandibular plane is the line joining the
inferiormost point on the mandibular symphysis and the
gonion (Go).
The mandibular plane angle
The mandibular plane angle is established by
relating the mandibular plane (MP) with the FHP.
The mean angle is 21.9˚. The range is 17˚- 28˚.

The incisor mandibular plane angle
Formed by intersection of the mandibular plane with a
line passing through the incisal edge and the apex of the root of
the mandibular central incisor.
-The mean value is 90˚ (with average MP angle)
The upper incisor to FHP
Formed by intersection of the FHP with a line passing
through the incisal edge and the apex of the root of the
maxillary central incisor.
The mean value is 110˚.

The interincisal angle
Established by passing a line
through the incisal edge and the
apex of the root of the maxillary
and the mandibular central incisors.
The mean value is 130˚. The range
is 125˚ -135˚.

The soft tissue assessment
Assessment of the adaptation of soft tissue to
the bony profile with consideration to the size, shape,
thickness and posture of the lips as seen on lateral
cephalogram.

Esthetic line (‘E’ line)
A line drawn through the
contour of the chin and nose.
The lower lip position should
be within a range of 2mm
behind the ‘E’ line to just
touching it.

‘S’ line
The lips in well
balanced face should
touch a line extending
from the soft tissue
contour of the chin to
the middle of the ‘S’
formed by the lower
border of the nose.

The facial contour line called ‘S’ line of Steiner. A line is drawn on the soft
tissue contour of the chin to the middle of the ‘S’ formed by the lower border
of the nose .In a well balanced face, the lips should touch the line.
If the lips are located beyond this line lips are believed to be
protrusive & interpreted as convex profile
If lip behind this line said to be retrusive with a concave profile.

Orthodontic Diagnosis

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