Clinical phototgraphy

"The photographic plate is the
scientist's retina, which is far
superior to that of the human eye for,
on the one hand, it records the
phenomenon perceived and, on the other,
in certain cases, it catches more than
the eye can see."
www.indiandentalacademy.com

Photography has become an increasingly
important tool in the dental profession.
Dental photography incorporates documentation
of the position of teeth and supporting
structures, radiographs, casts, and small
objects.
provides a legal record of facial features
before and after dental treatment.
documentation of orthodontic treatment with
pretreatment and post-treatment photographs
can be misleading if features on one or both
photographs are distorted.

Why the Photographs are
an essential part of
clinical records?

1. Unreliable memories:- patients and
parents tend to forget how severe the
original malocclusion was. Having slides
available at every visit reminds both the
orthodontist and the patient of the
original situation, against which all
improvements can be judged.
2. Medico legal requirements. If any
preexisting pathology or trauma. Close-up
photographs for any marked decalcification
or enamel fractures. The de-bonding
appointment is often the first time
patients or parents really focus in on the
labial enamel, and it may be the first time
they actually notice surface
decalcification, or fractures. Proper
records will help avoid any post-treatment
disputes. www.indiandentalacademy.com

3. Teaching needs- used in lectures,
posters, papers, and presentations.
photographs are important in dental
education, and patient education as
well.
4. Treatment evaluations- by evaluating
pre-treatment and post-treatment
photograph.

History of
photography

It was Leonardo DaVinci, who has
documented about “Camera Obscura or
pinhole camera” which is based on the
physics that a very small hole in a box
in a very dark room on a bright day will
direct light to create an image, that is
outside the hole, turned upside down .he
said that smaller the hole, sharper the
image.

In 1614 Angelo Sala,, a Dutch
scientist began experimenting with
substances called silver salts and
he stated that when powdered silver
nitrate is exposed to the sun, “it
turns as black as ink”.

In 1661 Many chemists contributed to the
advancement of the discovery that certain
materials change color when exposed to
light. Robert Boyle, reported that silver
chloride turned dark due to exposure to
light.

In 1727 Johann Heinrich SchulzeIn 1727 Johann Heinrich Schulze,, aa
professor of anatomy, discovered thatprofessor of anatomy, discovered that
silver salts, specially a piece of chalksilver salts, specially a piece of chalk
dipped in silver nitrate turned black fromdipped in silver nitrate turned black from
white when exposed to the sun. Thewhite when exposed to the sun. The
unexposed side remained white. Heunexposed side remained white. He
experimented creating crude photographicexperimented creating crude photographic
impressions, but eventually it all turnedimpressions, but eventually it all turned
black due to exposureblack due to exposurewww.indiandentalacademy.com

By the early 1800's, the optical
process from the “Camera Obscura" and
chemical processes (from materials
changing when exposed to light) were
beginning to be combined to form the
basis for the discovery of the
photographic process.

In 1806 The
first well-
documented
attempts to
produce photos
using light
sensitive
materials in a
camera were those
of Thomas
Wedgwood. but he
failed in keeping
the image
permanent. he
called the images
“sun prints”.www.indiandentalacademy.com

In 1827 The firstIn 1827 The first
successful picture issuccessful picture is
produced byproduced by NicephoreNicephore
NiepceNiepce with over anwith over an
eight hour exposure timeeight hour exposure time
. Niépce called his. Niépce called his
picturespictures “Heliographs”“Heliographs”
or “sun drawing”.or “sun drawing”.

In 1839 William
Henry Fox Talbot
invented process
that creates
permanent paper
negatives. He calls
it "Calotype"
process, which
allows for multiple
printings, based on
a paper negative.
This process was the
true fore runner of
today’s modern
photography process.

InIn 1839Daguerre
portrait creates
his first Photo.
He publicly
publishes details
of his process
and proudly names
the process,
“Daguerreotype”.
A high quality,
expensive process
producing a
single positive
image onto copper
plate coated with
silver. The
drawback was that
it was not
reproducible..www.indiandentalacademy.com

The Image
capture process
is then
introduced to the
public by Sir
John Herschel.. He
is credited with
naming the
process
""Photography“.“.
The term
"photography" is
derived from two
Greek words
meaning "light”
(phos) and
"writing"
(graphien).

What is a
camera

Lens - lets the light in and focuses it on
the film. It controls the focus of light,
from close up to infinity. The larger the
lens the more light.
The lens also effects how large the image
appears based on the focal length of the
lens.
In older camera the focusing ring adjust
the focus.
Most digital camera has a fixed lens
that work as a “jack of all the trades”.
Majority fixed cameras has a good
telephoto range between 100-250mm.
Types of lenses:-
1.Fish –eye (16mm to 8mm)
2.Wide angle(18- 35mm)
3.Standard to short telephoto(40-135mm)
4.Telephoto(150- 400 mm & beyond).

The shutter:- controls the light enters
the camera and for how long it enters.
The shutter in the lens is often
faster and quicker, but makes changing
the lens difficult. The shutter in
front of the film allows for easy
lens removal, but is often slow.
shutter it might be located in the
lens (leaf shutter) or it might be
located right in front of the film
(focal plane shutter).

Aperture:-aperture is the opening in the
lens that controls how much light enters
the camera.
it is adjusted by a ring on the outside of
the lens (aperture ring).
The larger the opening, more light is
allowed into the camera & less sharp the
final image will be.

Shutter Speed Dial - this regulates
how long the aperture stays open.
The slower the shutter speed, the
more light will come in. The faster
the speed, the less light will get
in to expose the film. Typical
shutter speeds are measured in
fractions of a second, such as: 1/30
1/60 1/125 1/250 1/500 and 1/1000 of
a second.

ASA Dial - The ASA number assigned
to film reflects how sensitive to
light it is, or how quickly it will
react to light. To take a picture
of fast action or low lighted
objects, use fast film. The higher
the number, the faster the film and
anything above 200 is considered
fast film.

Viewfinder:-
This is the opening in the back of the
camera through which the photographer
looks to aim the camera.

Film Advance:-Used to advance the film when
the film has been shot. Either manual or
automatic (using an electric motor).
The film advance is also a part of the
mechanism that locks the shutter by pulling
the curtain back to the right side of the
camera. This same turning of the lever also
advances the film counter in most cameras.

Rewind button - this is used only
after all the pictures have been
taken. It is used to rewind the
exposed film back into the
container.
Flash Shoe - This is the point at
which the flash or flash cube is
mounted or attached.

film holder inside the camera. This
must have some attachment that allows
for the film to be moved which can
either be a lever or a motor.

 Image resolution
The resolution of a digital camera is
often limited by the camera sensor
(usually a charge-coupled device or CCD
chip made up of light- sensitive sensor
element) that turns light into discrete
signals, replacing the job of film in
traditional photography. The sensor is
made up of millions of “unit/buckets" that
collect charge in response to light. Each
one of these buckets is called a pixel.
 This decrease leads to noisy pictures,
poor shadow region quality and generally
poorer-quality pictures.
1 Mega-pixel is equivalent to 1,000,000
pixels on a CCD sensor (charge coupled
device).
 A resolution of about 400,0000 pixels is
adequate for orthodontic use.

Optical zoom v/s digital
zoom:-
digital zooming is done by software
in computer while optical zooming is
done by lens magnifying the image.
Digital zooming is like taking a
10*8 inch image and cropping out the
centre to create a 6*4 inch image and
again enlarging it back to 10*8inch,
quality will be lost.
Always go by the camera’s optical
zoom figure and treat zoom as a
gimmick. www.indiandentalacademy.com

Advantages of digital camera
1)Immediate Review of Recorded Images
This is one of the most important
advantages of digital cameras over
conventional cameras. we can check the
recorded image a few seconds after taking
the picture and decide whether it is
satisfactory.
2)Tuning of Parameters
In macro photography, it is important to
be able to manually adjust the
parameters: the size of the lens opening
(aperture), exposure, zoom of the camera
and the shutter speed.www.indiandentalacademy.com

The active component of film is an emulsion ofThe active component of film is an emulsion of
light-sensitive crystals coated onto a transparentlight-sensitive crystals coated onto a transparent
base material. The production of an image requiresbase material. The production of an image requires
two steps.two steps.
First, the film is exposed to light, whichFirst, the film is exposed to light, which
activates the emulsion material but produces noactivates the emulsion material but produces no
visible change. The exposure creates a so-calledvisible change. The exposure creates a so-called
latent image.latent image.
Second, the exposed film is processed in a seriesSecond, the exposed film is processed in a series
of chemical solutions that convert the invisibleof chemical solutions that convert the invisible
latent image into an image that is visible aslatent image into an image that is visible as
different optical densities. The darkness ordifferent optical densities. The darkness or
density of the film increases as the exposure isdensity of the film increases as the exposure is
increased.increased.
The Two
Steps in
the
Formation
of a Film
Image

Clinical Procedure
Photographs should definitelyPhotographs should definitely
precede impressions, sinceprecede impressions, since
alginate invariably remains on thealginate invariably remains on the
lips and cheeks and between thelips and cheeks and between the
teeth.teeth.
Take extra-oral before intraoralTake extra-oral before intraoral
photographs, because the patient’sphotographs, because the patient’s
lips will be pulled and stretchedlips will be pulled and stretched
during the intraoral photography.during the intraoral photography.

Views
For a complete photographic record, the recommended
views are:-
Initial
• Four extra-oral :—
full-face,
full-face grinning broadly
left profile (right profile only in cases of facial
asymmetry),
three-quarter profile,
.
• Five intraoral
(in occlusion)—left and
right buccal segments,
anterior view, and
mirror images of both dental arches.
• Close-ups of any areas of concern—fractured,
cracked, or crazed teeth, non-vital teeth, or areas
of hypoplasia or hypo-mineralization.

Progress (during treatment or between
phases of treatment)
• Extra-oral:— same as above if changes have
occurred.
• Intraoral— same as above.
• Close-ups of any unusual or noteworthy
mechanics or problem areas. Removable
appliances used during treatment are often
photographed.
End of treatment
Same as initial. Photographs of the
retainers are also important.
Functional occlusion (selected cases)
Three intraoral —right lateral excursion,
left lateral excursion, and anterior
protrusion. These will demonstrate the
presence of desirable guidance and absence
of undesirable contacts.

Full-Face Extra-oral View Objective: A
symmetrical shot from the top of
the patient’s head to an inch or
two below the chin.
Ask the patient to avoid looking
directly at the end of the
camera, but to look into the
distance over the photographer’s
shoulder.
Set the camera to the extraoral
mark on the barrel of the lens.
To ensure consistent
magnification, the patient’s
eyes and cheekbones should be
focus.
one full-face view with the lips
at rest and one with as broad a
smile as possible, fully
exposing the teeth and gingiva.
Note that patientNote that patient
is properlyis properly
aligned withaligned with
regard toregard to
FrankfortFrankfort
horizontal line.horizontal line.

Smiling Full-Face Extra-
oral View
Extraoral full-face
view, grinning
broadly.

Profile Extra-oral View
Objective: A
photograph from the
top of the patient’s
head to an inch or
two below the chin.
The patient’s nose
should be a short
distance from the
edge of the frame;
the back of the head
is not essential.
Ask the patient to
keep the lips at rest
.

Three-Quarter Extra-oral View
Objective: from the top
of the head to one or two
inches below the chin.
patient’s body should be
at a right angle to the
camera, as in the profile
shot, but the patient
should turn the head
about 45°, until the
opposite eyebrow can be
seen.
Focus on the cheekbone
and the side of the
nose . Patient looks towardPatient looks toward
camera immediatelycamera immediately
before three-quarterbefore three-quarter
shot is taken.shot is taken.

Hairstyle
A, Hairstyle canA, Hairstyle can
distract from facialdistract from facial
analysis.analysis.
B, Hair should beB, Hair should be
pulled back. Thispulled back. This
allows forallows for
relationship betweenrelationship between
tragus and infra-tragus and infra-
orbital rim to beorbital rim to be
evaluated. Sameevaluated. Same
applies to hair downapplies to hair down
over foreheadover forehead..

HEAD POSITION
it is difficult to reproduce
photographs with assured
accuracy, it is clinically
possible to produce
consistent results that are
useful for comparisons.
Certain anatomic references
assure consistent
pretreatment and post-
treatment head position.

frontal views, frame
should encompass the
head and clavicle.
Distance is frequently
fixed, with the camera
and subject at a
constant, reproducible
distance. This assures
consistent perspective
for all subjects and
similar reproduction
ratios and subject-to-
camera distances.
The inter-pupillary
line should be
parallel to the
horizontal plane.

The distance from the outer
canthus of the eye to the
hairline should be equal on
each side.
The line from the outer
canthus of the eye to the
superior attachment of the
ear (C-SA line) should also
be parallel to the
horizontal plane.
Both lines are used to
establish consistent
parallelism between the eyes
and the horizontal plane and
to prevent tilting of the
head in frontal and lateral
views.

 Another established
method for head
orientation was
termed by Broca in
1862 as natural head
position. Broca
defined this
position in the
following way: "When
a man is standing
and when his visual
axis is horizontal,
he (his head) is in
the natural
position". This has
been shown to be a
reproducible
position.Ideal head position and
perspective for a frontal
view. www.indiandentalacademy.com

Ideal head position for a lateral view.
Sketch showing line from outer canthus to
superior attachment of ear (A) should be parallel
to the floor.
encompassing area is top of the head to
collarbone (C).

Common Errors in Clinical extra-oral Photography
When poor photos were taken, the causes
can be easily identified and corrected.
The most common errors are:
1. Misrepresentation of skeletal pattern.
This can occur if the patient tilts the
head too far backward or forward .Try to
get every patient into a horizontal
Frankfort plane or “natural head
position”.

A. Head tilted
forward,
exaggerating
mandibular
retrognathia. B.
Head tilted
backward, giving
Class III
appearance.

2. Inconsistent magnification between
stages of treatment. Marks on the
barrel of the lens will indicate the
proper positions for both intraoral
and extraoral shots .

backward tilt of head
Distortion
caused by
backward tilt of
head. The chin
appears
prominent,
particularly in
the lateral
view.

forward tilt of head
Distortion
caused by
forward tilt of
head. The chin
apppears to be
receded.

Lateral head rotation
The view is not
symmetrical.
The distance
from outer
canthus to
hairline is not
equal on both
sides.

CHANGES IN MANDIBULAR POSITION
The photographs have shown
that, the lateral view is far
more sensitive than the frontal
view. It is possible to observe
differences of as little as 1.8
mm in the lateral view while
differences of as much as 7.5
mm were difficult to observe in
the frontal views

mandibular
positions shown
in lateral
views.
Differences
between each of
the positions are
easily discerned.
A, Centric
relation; B,
centric
occlusion; C,
extreme
protrusive
position.

Two mandibular positions
shown in frontal view
. Differences
between the two
extremes are
difficult to
discern.
A, Centric
relation;
B, extreme
protrusive
position.

Variations in head position
mask true changes in jaw
position
A. Extreme
protrusive
position with a
forward head
tilt.
B- centric
relation
position with
backward head

Variations in head position
accentuate true changes in
mandibular position
. A, Extreme
protrusive
position with
backward head
tilt.
B, centric
relation
position with
forward head
tilt.

Distorted view
caused by
incorrect camera
position
A, Camera too
high.
B, camera too
low.

Intraoral Anterior ViewObjective: To show the
teeth in maximum inter-
cuspation.
The occlusal plane
should be horizontal,
with the clinically
correct midline as close
to the center of the
frame as possible.
The patient should be
seated in the dental
chair at a comfortable
height for the
clinician. Ask the
patient to keep the
tongue back to provide
good contrast for the
teeth. www.indiandentalacademy.com

Ask the patient to swallow before
placing the retractors, and aspirate
excess saliva from the field of view.
Pull the retractor laterally and as
far forward as possible not backward,
which will compress the lips against
the alveolus.
focus on the lateral incisor area or
the Mesial of the canine.

Intraoral Buccal ViewObjective: To show the
teeth in maximum
inter-cuspation, from
the labial surface of
the central incisor to
the distal of the
first molar.
The patient is seated
upright, with the head
turned as far as
possible to the left
or right.

•always warn the patient that wealways warn the patient that we
have to pull the retractor firmlyhave to pull the retractor firmly
Immediately before snapping.Immediately before snapping.
• pull the retractor another 5mmpull the retractor another 5mm
distally to make sure the distaldistally to make sure the distal
surface of the first molar can besurface of the first molar can be
recorded.recorded.

Upper Occlusal Mirror Shot
Objective: to capture the maxillary arch
from 1-2mm anterior to the labial
surface of the central incisors to the
distal of at least the first molars.
the palatal surfaces of most of the
incisors should be visible, if the
patient and mirror are correctly
positioned and the incisors are not
unduly retro-clined.

•Procedure: pull the upperProcedure: pull the upper lip upward,lip upward, laterally,laterally,
and forwardand forward. This will set up a background of. This will set up a background of
sulcus mucosa for the incisors, while removingsulcus mucosa for the incisors, while removing
all skin and most of the lips from view.all skin and most of the lips from view.
•Place the mirror in the mouth with the large endPlace the mirror in the mouth with the large end
against the distal margins of the terminalagainst the distal margins of the terminal
molars, and press the mirror down onto the lowermolars, and press the mirror down onto the lower
incisors.incisors.

Angle theAngle the cameracamera
at 45° to theat 45° to the
mirror,mirror, which inwhich in
turn is angledturn is angled
atat 45° to the45° to the
arch.arch.
Ask the patientAsk the patient
now to “opennow to “open
twice as wide”,twice as wide”,
producing aproducing a
further opening.further opening.
Ask the patientAsk the patient
to breatheto breathe
through the nosethrough the nose
for a moment tofor a moment to
reduce fogging.reduce fogging.

Lower Occlusal Mirror Shot
Objective: justObjective: just
anterior to the labialanterior to the labial
surfaces of the lowersurfaces of the lower
incisors to the distalincisors to the distal
of theof the second molarssecond molars..
The midline should beThe midline should be
centered, if clinicallycentered, if clinically
correct, to providecorrect, to provide
symmetry.symmetry.
Ask the patient toAsk the patient to
place the tongue aboveplace the tongue above
and behind the mirrorand behind the mirror
if possible.if possible.

•the lips are pulledthe lips are pulled downward, laterally, anddownward, laterally, and
slightly forwardslightly forward to show the mucosa as ato show the mucosa as a
background to the incisorsbackground to the incisors
•ask the patient open as wide as possible, and atask the patient open as wide as possible, and at
the last moment move the distal end of the mirrorthe last moment move the distal end of the mirror
slightly away from the terminal molars.slightly away from the terminal molars.
•Lower occlusal mirror shot includes incisors andLower occlusal mirror shot includes incisors and
terminal molars, with no retractors or fingersterminal molars, with no retractors or fingers
visible.visible. www.indiandentalacademy.com

Error in Intraoral Shots
1. Lack of symmetry.
-occlusal plane should be horizontal and
bisecting the frame,
-frame should be filled with teeth, with
first molars at the outer edges of the frame.
-Little of the retractor and none of the
cheek or lips should be visible.
Marked tilting of
occlusal plane and
inadequate
retraction produce
poor photograph.

2. Some teeth out of focus. In
intraoral anterior shots, the focus
should be on the lateral incisors. In
intraoral buccal shots, the focus
should be on the premolars.

Error in Intraoral Shots
3. Backdrop of oral
mucosa not provided.
the lips should be
pulled laterally, and
forward, so the oral
mucosa, rather than
skin, will form the
background for the
teeth in all views.
Pulling the retractors
backward will compress
the lips against the
alveolus, producing a
poor photograph.
Photograph with
inadequate forward
retraction and
incorrect
magnification (teeth
not filling frame).

Error in Intraoral Shots
4. Foreshortening. If the patient
does not open wide enough for the
mirror shots, foreshortening and
arch distortion will occur. The
occlusal mirror should be rested
against the most distal tooth in the
arch being photographed, then placed
on the opposing incisor tips. When
ready to take the photograph, ask
the patient to “open twice as wide”.
Always photograph the larger of the
two arches first, filling the frame
with teeth, and keep the same
magnification for the smaller arch.

5. Misrepresentation of the sagittal discrepancy
- Proper selection of retractors helps
a great deal,
-turn as far as possible to the left
or right against the pressure of the
retractor.
-shot taken perpendicular to the
posterior segments if possible.
-patient must be warned that firm
retraction will be required.
A. Sagittal
discrepancy
misrepresented in
shot with inadequate
retraction and poor
camera position.
B. Shot repeated
perpendicular to
posterior segment
with proper
retraction.www.indiandentalacademy.com

A LIP RETRACTOR
for intraoral photography
Adequate access for occlusal intraoral
photographs has been limited by the
difficulty in management of retraction of
the lips and cheeks. Dr. Brainerd F.
Swain, recognizing this inherent problem,
has developed a retractor specifically for
occlusal intraoral photographs.

The fabricated lip
retractor. Top and oblique
view. fabricated from
denture-base acrylic and
can be made in various
sizes and shapes. A
retractor 7½ cm wide and 12
cm long is almost universal
angle of approximately 135°
special plastic lipspecial plastic lip
retractorsretractors , horseshoe, horseshoe
portion of the retractorportion of the retractor
is traced from maxillaryis traced from maxillary
archwire template. Thearchwire template. The
handle is abouthandle is about 3" long3" long
and ¾" wideand ¾" wide to provide anto provide an
easy grip for the patienteasy grip for the patient
and angled atand angled at 50* angle.50* angle.

Using the Lip Retractor
Placement of the lip retractor and
occlusal mirror for mandibular and maxillary
occlusal photographs.

Cheek retractors (available in
many shapes and sizes). The best
are the double-ended kind, which
come in two sizes .These allow
patients of all sizes to be
photographed, maximizing soft-
tissue retraction and minimizing
the amount of retractor shown in
the photo.

Optimal placement of the retractors
are ten o’clock and two o’clock
position for the upper occlusal and
eight o’clock and four o’clock
position for the lower occlusal. Ask
the patient to bends the necks back
as far as possible and looking at
the ceiling.

Flash Capability
In conventional dental photography, a ring
flash is needed to obtain uniform illumination
of the subject in macro mode. External light
sources cannot be used, because the lips and
chin, the camera, and the operator (who is
close to the subject) will create shadows.
Most digital cameras have built-in flash units
on one side of the lens, which often produce
uneven light distribution in intraoral
photography

If camera does not permit the use of a ring
flash, the subject illumination can be
improved in two ways:
1. Light deflectors. A mirror system can
effectively diffuse the flash light on both
sides of the subject.
2. Light-activated external flash. It may
be possible to mount an external flash on
the opposite side of the built-in flash.
The two flashes will operate
simultaneously, producing good illumination
of the subject without shadows.
Light deflector onLight deflector on
digital cameradigital camera
corrects asymmetry ofcorrects asymmetry of
flash unit.flash unit.

Photographs taken with camera in
A. In front view, light is well
distributed.
B. In lateral view, no shadows are
present.

Lightening:-
it is best to photograph in consistent
lightening condition.
it is highly desirable to have a pure and
consistent background color in the profile
photographs. To achieve this, utilize a slave
flash bulb by shining it onto the back wall,
preferably in a neutral color such as white.

speciallyspecially mounted slave flash light boxmounted slave flash light box for morefor more
controlled lightening.controlled lightening.
the light box should be mounted well within the range forthe light box should be mounted well within the range for
the different patient heights.the different patient heights.
For the best result, place the patient chair aboutFor the best result, place the patient chair about 30-3530-35
cms in the front of the light box.cms in the front of the light box.

Multi-blitz Mini-
light which has
ring-type, highly
durable flash bulb
and smaller
centrally located,
less durable, bulb
for floodlighting.
FrontalFrontal
projection in widerprojection in wider
rooms, Multi-blitzrooms, Multi-blitz
Mini-lights shouldMini-lights should
be mounted onbe mounted on
tripods. In sotripods. In so
doing, extremedoing, extreme
angles in flashangles in flash
presentation can bepresentation can be
avoided.avoided.

Photography analysis
Photograph is a indirect method of
patient evaluation.
Profile analysis:- overall facial
profile and dento-facial skeletal
morphology are evaluated in the
saggital and vertical planes.

Vertical plane :-Two methods
 1)Traditional method:-
face is divided into
thirds:-
1. Upper 3rd
: trichion
-glabella
2. Middle 3rd
: glabella-
subnasale
3. Lower: subnasale –
menton
 All these thirds should
be of same size;
 Drawback:
1. Hairline is quite
variable
2. Glabella is a
subjective point of
reference.

2)Evaluation of the
two lower thirds:-
1.Nasion – subnasale
2.subnasale – menton.
If nasion- menton equal 100
percentage, 43 prcentage
will corresponds to the
upper third (Na-Me)and the
rmaining 57 percentage to
the lower third(Sn-Me).
Again the lower third is
subdivided in two unequal
parts.
1.Subnasale - stomion
superious:- 1/3rd
2.Stomion inferious- menton:-
2/3rd

Facial exposure
Upper ,middle and
specially lower 3rd
should be evaluated.
Symmetry is assessed.
Divide the face in two
halves, tracing the
midline from the centre
of the glabella – equi-
distant to both medial
canthi and perpendicular
to pupillary plane.

 “’rule of fifth’” states
that the total width of the
face equal 5 eye width.
For analyzing symmetry in
depth, the face is divided
into fifths, tracing lines
parallel to the midline, that
go through the medial and
lateral canthi and the most
lateral points at the level of
the parital bones.
The nasal width , measured
from ala to ala, involve the
central fifth; thus it is
equal to the inter-canthal
distance (distance between
both medial canthi).
The lip distance is measured
from commissure to commissure
and equals the distance
between the medial limbi of
the eye, which in turns
corresponds to the medial edge
of the iris circumference.

 Powell’s analysis
 Powell’s aesthetic triangle analyzes the
main aesthetic mass of the face;
forehead, nose, lips, chin, and neck
using interrelated angles.
 Analysis moves from stable structure the
forehead to the chin. it consist of lines
and angles traced over the soft tissues,
using a well oriented photograph. Lip
should be at rest for this analysis.
 Facial plane
1. Naso- frontal angle
2. Naso-facial angle
3. Naso-mental angle
4. Mento-cervical angle

Facial plane
Is traced on the soft
tissues starting from the
glabella ( the most
prominent point of the
forehead on the mid-
saggital plane), to
pogonion (the most
anterior point on the
chin)

Naso-frontal
angle:- Angle
between the line
tangential to glabella
and a line tengential
to the dorsum of nose.
normal range is
between 115* to 130*.
nasal deformity such
as protrusion or
depression in the
dorsum can be
evaluatted by this
angle.

Naso-facial
angle:- Angle
between facial
plane and the line
tengential to the
dorsum of nose.
Describe nasal
projection on the
patient profile.
For proper
esthetics , value
close to 30* and
40* are favored for
women and men
respectively.

 Naso-mental angle:-
Naso-mental angle lies at
the intersection with the
dorsum of nose. It is most
important angle between the
aesthetic triangle.
 Normal value is between 120
* to 132*.
 This angle related to nose
and chin, two surgically
modifiable masses. The chin
can also be modified by
orthopaedic and orthodontic
maneuver.
 It is important to record
the relationship between:
1. The nasofacial angle
2. The nasomental angle
3. The distance between the
lip and e- plane.

 Changes in aesthetic triangle values caused by chin advancement Naso-
facial angle become smaller.
Naso-mental angle become larger.
An increase in the negative distance of the lip in
relation to the aesthetic plane.
In short, the powell’s triangle does not only deal
with shape, size and location of all existing
aesthetic masses of the profile in isolation but as a
whole. the ideal goal is global balance between them.

Mento-cervical angle
A line is traced from cervical
(C) to menton (Me).
Point C is the deepest point
formed by the sub-mandibular
area and the neck.
The mento-cervical angle lies
at the intersection of glabella
– pogonion. This line is traced
tangential to the sub-
mandibular area, which
intersects both point C and Me.
Norm is 80* to 95*.

It is influenced by the shape
and amount of the sub-
mandibular adipose tissue.
The more beautiful the
profile , the more acute this
angle will be within the
normal range.
The position of the chin also
exert an influence over this
angle. surgical retrusion of
the chin widens the angle by
changing the position of the
G-Pog plane and increasing
thickness in the sub-
mandibular soft tissue as the
chin retrudes, converly,
surgical advancement of the
chin tends to make this angle
acute. www.indiandentalacademy.com

 POWELL’S
AESTHETIC
TRIANGLE
 Norms
1. Naso-frontal
angle - 115*
to 130*
2. Naso- facial
angle - 30*
to 40*
3. Naso-mental angle
- 120* to 132*
4. Mento-cervical
angle - 80* to
95*

Complimentry studies
 1) nasal evaluation:- change in the
nose projection can be checked by
powell’s triangle, can be
crosschecked by checking
1. Nose length:base ratio by baum’s
ratio and good’s ratio
2. Nose projection and lip length –
simon’s method.

Baum’s method
Vertical line is drown from
nasion to sub-nasale.
A vertical line is drown
perpendicular to the vertical
line and passes through the
tip of nose. ’tip of nose’ is
the point of the nose farthest
from the vertical line.
The ratio between both line is
2:1, this ratio will result in
naso-facial angle of
approximately 42*.
Powell consider that this
ratio gives too much nose
projection and prefer a ratio
of 2.8:1 ratio , which will
result in nasofacial angle of
approximately 36*

Good’s method
Similar to Baum's, but
the vertical line is
drawn from the point
where the nasion crosses
the ala canal. the
dorsum is measured from
nasion to tip.
The ratio between ala –
tip (horizontal) and
nasion – tip (vertical)
is 0.55 to 0.60.
Ratio of 0.55 gives a
naso-facial angle of
approximately 36*.

Simon’s method
It establishes a 1:1
ratio between the
length of the upper lip
and the base of nose.
The upper lip is
measured from the sub-
nasale to the muco-
cutaneous edge of the
upper lip (upper
vermelion) , while the
base of the nose is
measured from subnasale
to the tip of the
nose.

Naso-labial angle evaluation
This angle is formed between
the base of the nose and the
upper lip. Two lines are drown
from sub-nasale ;the
horizontal line is tangent to
the most anterior point of the
nose while the vertical line
is tangent to the muco-
cutaneous edge of the upper
lip (upper vermilion).
Norm is b/w 90* to 110*.
This serves as a landmark for
planning corrective measure
because both teeth and
skeletal malformation of the
maxilla exert an influence on
this angle.

Legan’s lower facial angle
This angle is formed by the
subnasale – gnathion (Sn-Gn)
and the gnathion- cervical
point lines (Gn - C).
The average value for this is
100* with a standard
deviation of 7*.
The ideal ratio between the
lower facial height of the
face (Sn-Gn) and its depth
(Gn-C) is 1.2 .

Rickett’s lip
analysis
The reference line
used by RICKETT’s is
drawn from tip of
the nose to skin
pogonion.
Normal relations
means that the upper
lip is 2-3mm, the
lower lip is 1-2mm
bhind the this line.

STEINER’s lip
analysis:-
The upper reference
plane for the
steiner’s analysis is
at the centre of the
S-shaped curve
between tip f nose
and subnasale. soft
tissue pogonion
represents the lower
reference point.
Lip lies behind( line
connecting these two
points) are flat and
lips lies anterior to
it are prominent.

CONCLUSION:- photography can be a
great asset to our practice. Proper
equipment and component selection is
crucial. With some experimentation
and practice, we can create
consistent and professional –
quality records for our diagnosis,
presenting to patient’s parents and
to communicate effectively with
referrals and colleagues.

REFERENCES
STANDARDIZED POTRAIT PHOTOGRAPHY FOR DENTAL
PATIENTS-AM.J.O-1990 SEP-LEWIS.
FACIAL PHOTOGRAPHY FOR THE ORTHODONTIC OFFICE-
AJO-DO 1997 MAY-GEORGE MEREDITH.
CLINICAL PHOTOGRAPHY IN ORTHODONTICS-JCO 1997 NOV.
DIGITAL PHOTOGRAPHY IN ORTHODONTICS-JCO NOV 1998-
GIORGIO
ORTHOSCAN CAMERA-1973 JUNE.
RECENT DEVELOPMENTS IN CLINICAL PHOTOGRAPHY-
JONATHAN SANDLER BJO,VOL26,1999
IMAGING IN ESTHETIC DENTISTRY-GOLDSTEIN.

this line forms an angle
with the FRANKFORT PLANE
ranging from 80* and 95*

When consistent head position is not
reproduced, distortion of appearance
is likely.
A backward head tilt gives a
prognathic appearance, particularly in
the profile view.
A forward head tilt gives a retro-
gnathic appearance.
Head rotation alters the appearance of
symmetry in frontal views.

 WHILE USING
CAMERA

5. for Intraoral shots retraction
should be well enough.
6. For each photograph, the dental
light should be adjusted on the
subject to aid in focusing. focal
distance should be adjusted by
setting the barrel to the
appropriate mark.
7. Regularly audit photographic
technique to ensure the photos are
of a consistently high standard.

1. enough frames of film should be
available.
2. the batteries should be fully
charged.
3. Photographing the patient’s name
before taking a series will greatly aid
in sorting.
4.extraoral shots should be taken in
front of a standard background—for
instance, a piece of blue poster board
mounted on the operatory wall or blue
cloth.
camera should be turned to 90° to
produce a “portrait” (vertical) mode
rather than a “landscape” (horizontal)
mode, which wastes space on both sides
of the subject.www.indiandentalacademy.com

EVERY camera has these basic parts.
This first and main part is called the body.
The second part is the shutter which might be
located in the lens (leaf shutter) or it might
be located right in front of the film (focal
plane shutter).
The shutter controls the light enters the
camera and for how long it enters. The shutter
in the lens is often faster and quicker, but
makes changing the lens difficult. The shutter
in front of the film allows for easy lens
removal, but is often slow.

 Lens - It draws the light into the camera and focuses it on the film plane.
 Shutter - It open and closes to control the length of time light strikes the film.
There are two types of shutters: a leaf shutter, located between or just behind
the lens elements, and a focal plane shutter, located in front of the film plane
 .Shutter Release - The button that releases or "trips" the shutter mechanism.
 Film Advance Lever or Knob - It transports the film from one frame to the
next on the roll of film.
 Aperture - It dilates and contracts to control the diameter of the hole that the
light passes though, to let in more or less light. It is controlled by the f-stop
ring.
 Viewfinder - The "window" through which you look to frame your picture.
 Film Rewind Knob -This knob rewinds the film back into the film cassette.
 Camera Body - The casing of the camera which holds the encloses the camera
pats.
 Flash Shoe - This is the point at which the flash or flash cube is mounted or
attached.
 Self-Timer - This mechanism trips the shutter after a short delay - usually 7 to
10 seconds - allowing everyone to be in the photograph.
 Shutter Speed Control - This know controls the length of time the shutter
remains open. Typical shutter speeds are measured in fractions of a second,
such as: 1/30 1/60 1/125 1/250 1/500 and 1/1000 of a second.

TheThe Eastman Kodak Co.
introducesintroduces
nitrocellulose basednitrocellulose based
flexible film, whichflexible film, which
produced a film withproduced a film with
the clarity of thethe clarity of the
glass plates.glass plates.

Aperture is in the lense and is like
piece of metal that can change the size
of the hole that lets in light. it is
TIMED by the shutter speed dial, usually
on top of the camera. The larger the
number the SHORTER the time. A short
time lets in light quickly which will
stop the MOTION an object might have as
it travels across the film while being
exposed.
There are two types of shutters. One is
an opening in the camera lens and the
other is a curtain, usually cloth or
rubber, that moves across the front of
the film.
Shutter Release Button - the control
that releases the aperture opening,
lifts up the mirror, and exposes the
film to the light.

The angle at which the front light is
directed at the patient is extremely
important in obtaining repeatable
satisfactory results.
In medical photography, oblique
lighting is often used because it is
convenient For work that is free of
distortion and shadow, it is seldom
adequate.
The angle between the light and the
lens axis tends to introduce extraneous
shadows so that important areas are
often underexposed, producing a
misleading result.

 THE PHOTOGRAPHIC PROCESS
 CONTENTS   The production of film density and the formation of a visible image is a two step process.
The first step in this photographic process is the exposure of the film to light, which forms an invisible
latent image. The second step is the chemical process that converts the latent image into a visible image
with a range of densities, or shades of gray.   Film density is produced by converting silver ions into
metallic silver, which causes each processed grain to become black. The process is rather complicated
and is illustrated by the sequence of events shown below.
Sequence of Events That Convert a Transparent Film Grain into Black Metallic Silver
   Each film grain contains a large number of both silver and bromide ions. The silver ions have a one-
electron deficit, which gives them a positive charge. On the other hand, the bromide ions have a negative
charge because they contain an extra electron. Each grain has a structural "defect" known as a sensitive
speck. A film grain in this condition is relatively transparent.

Lighting
Two types of lighting are required for successful
extra-oral photography:
1)conventional front lighting and
2) adequate back lighting.
 A light box similar to the type used to view x-
rays makes an ideal background light.
A second background technique involves the use of a
dark felt like material behind the patient, which,
in the opinion of some workers, portrays the
outline of the face to better advantage.
 A third technique, developed by Dr. L. Cushner of
Tufts University Orthodontic Department, contains a
stroboscopic flash one foot behind the patient at
the level of the patient's head. This strobe is
synchronized to flash at the same time as the front
strobe unit. The camera systems for instantaneous
film do not contain back lighting attachments.
These must be provided by the practitioner. Front
or direct lighting is accomplished by electronic
strobe, flash bulbs, or wink light. In some cases
the high speed film permits room lighting to be
used. The more sophisticated camera systems provide
electronic strobe units (see Table I) .

    Fixing
 CONTENTS   After leaving the developer the film is transported into a second tank,
which contains the fixer solution. The fixer is a mixture of several chemicals that
perform the following functions.
 Neutralizer
    When a film is removed from the developer solution, the development continues
because of the solution soaked up by the emulsion. It is necessary to stop this action to
prevent overdevelopment and fogging of the film. Acetic acid is in the fixer solution
for this purpose.
 Clearing
    The fixer solution also clears the undeveloped silver halide grains from the film.
Ammonium or sodium thiosulfate is used for this purpose. The unexposed grains
leave the film and dissolve in the fixer solution. The silver that accumulates in the fixer
during the clearing activity can be recovered; the usual method is to electroplate it
onto a metallic surface within the silver recovery unit.
 Preservative
    Sodium sulfite is used in the fixer as a preservative.
 Hardener
    Aluminum chloride is typically used as a hardener. Its primary function is to shrink
and harden the emulsion.

    The invisible latent image is converted into a visible image by the chemical process of development.
The developer solution supplies electrons that migrate into the sensitized grains and convert the
other silver ions into black metallic silver. This causes the grains to become visible black specks in the
emulsion.   Radiographic film is generally developed in an automatic processor. A schematic of a
typical processor is shown below. The four components correspond to the four steps in film
processing. In a conventional processor, the film is in the developer for 20 to 25 seconds. All four
steps require a total of 90 seconds.
A Film Processor
   When a film is inserted into a processor, it is transported by means of a roller system through the
chemical developer. Although there are some differences in the chemistry of developer solutions
supplied by various manufacturers, most contain the same basic chemicals. Each chemical has a
specific function in the development process.
 Reducer
 Chemical reduction of the exposed silver bromide grains is the process that converts them into
visible metallic silver. This action is typically provided by two chemicals in the solution: phenidone
and hydroquinone. Phenidone is the more active and primarily produces the mid to lower portion of
the gray scale. Hydroquinone produces the very dense, or dark, areas in an image.
 Activator
    The primary function of the activator, typically sodium carbonate, is to soften and swell the
emulsion so that the reducers can reach the exposed grains.   Restrainer
    Potassium bromide is generally used as a restrainer. Its function is to moderate the rate of
development.
 Preservative
    Sodium sulfite, a typical preservative, helps protect the reducing agents from oxidation because of
their contact with air. It also reacts with oxidation products to reduce their activity.
 Hardener
    Glutaraldehyde is used as a hardener to retard the swelling of the emulsion. This is necessary in
automatic processors in which the film is transported by a system of rollers.

In the lower third we also deal
with:-
-the inter-labial gap:- the
vertical distance between the upper
and lower lip (sts -sti) in are
laxed labial position’ ideally it
should be 3mm.
-the relationship between the
upper incisors and the upper lip.

The pixel count alone is commonly presumed to indicate the
resolution of a camera, but this is a misconception. There are several
other factors that impact a sensor's resolution. Some of these factors
include sensor size, lens quality, and the organization of the pixels
(for example, a monochrome camera without a Bayer filter mosaic
has a higher resolution than a typical color camera). Many digital
compact cameras are criticized for having too many pixels, in that
the sensors can be so small that the resolution of the sensor is greater
than the lens could possibly deliver.
Excessive pixels can even lead to a decrease in image quality. As
each pixel sensor gets smaller it is catching fewer photons, and so
the signal-to-noise ratio will decrease.

    Conventional film is layered, as illustrated in the following figure. The active component is an emulsion layer
coated onto a base material. Most film used in radiography has an emulsion layer on each side of the base so that it
can be used with two intensifying screens simultaneously. Films used in cameras and in selected radiographic
procedures, such as mammography, have one emulsion layer and are called single-emulsion films.

Cross-Section of Typical Radiographic Film
    Base
 CONTENTS   The base of a typical radiographic film is made of a clear polyester material about 150 µm thick. It
provides the physical support for the other film components and does not participate in the image-forming
process. In some films, the base contains a light blue dye to give the image a more pleasing appearance when
illuminated on a viewbox.
    Emulsion
 CONTENTS   The emulsion is the active component in which the image is formed and consists of many small
silver halide crystals suspended in gelatin. The gelatin supports, separates, and protects the crystals. The typical
emulsion is approximately 10 µm thick.   Several different silver halides have photographic properties, but the one
typically used in medical imaging films is silver bromide. The silver bromide is in the form of crystals, or grains,
each containing on the order of 109 atoms.   Silver halide grains are irregularly shaped like pebbles, or grains of
sand. Two grain shapes are generally used in film emulsions. One form approximates a cubic configuration with its
three dimensions being approximately equal. Another form is tabular-shaped grains. The tabular grain is relatively
thin in one direction, and its length and width are much larger than its thickness, giving it a relatively large surface
area. The primary advantage of tabular grain film in comparison to cubic grain film is that sensitizing dyes can be
used more effectively to increase sensitivity and reduce crossover exposure.

 Apertures on the common camera
 1.4 - 2 - 4 - 5.6 - 8 - 11 - 16 - 22 - 32
Each of these represents a fraction again, thus 2 is 1/2 and 22 is 1/22
representing the basic size of the opening in relation to the focal length of
the lens.
Shutter Speeds on the common camera
1000 - 500 - 250 - 125 - 60 -
30 - 15 - 8 - 4 - 2 - 1 - B
Each speed is a fraction of a second -
like 1/1000th of a second or 1/4 of a
second. B stands for bulb and holds the
shutter open as long as the shutter
release is held down.

• Louis and Auguste
Lumiere invent theinvent the
Cinematography , aCinematography , a
combination camera-combination camera-
projector that canprojector that can
project moving imagesproject moving images
onto a screenonto a screen

ConventionalConventional Anything in range from infinity to normalAnything in range from infinity to normal
Close-up photographyClose-up photography > x 1> x 1
PhotomacrographyPhotomacrography x 1 - x 50x 1 - x 50
Single stageSingle stage
magnificationmagnification
PhotomicrographyPhotomicrography x25 - x 3000x25 - x 3000
Two or moreTwo or more
stages ofstages of
magnificationmagnification
Many lensesMany lenses
that arethat are
described asdescribed as
close-up onlyclose-up only
go as close asgo as close as
1:4 (Quarter-1:4 (Quarter-
life size) orlife size) or
1:2 (Half-life1:2 (Half-life
size)size)

George Eastman
introduces theintroduces the
"Kodak" box Camera ."Kodak" box Camera .
Once exposed, theOnce exposed, the
camera and the filmcamera and the film
are sent back to theare sent back to the
Eastman Dry Plate andEastman Dry Plate and
Film Co. forFilm Co. for
developingdeveloping.

Fabrication of Lip
Retractor1. Trace the outline of the retractor from the template onto a
piece of pink denture baseplate acrylic 5" ´ 5" ´ 1/16“.
2. Cut the acrylic to the outline drawn. The most rapid method
for cutting is to use an electric jig, band or saber saw. An
adequate but less ideal method is to use an acrylic bur.
3. Smooth the cut surfaces with an acrylic bur or stone and
polish these edges with pumice. The flat surfaces are not
polished. A dull finish is desired to minimize glare and
reflection of flash light.
4. Gently heat the retractor in a flame. When soft, bend at the
junction of the handle and body to
Fig. 4 Templates showing outline of lip
retractor (above) and 135° bend at junction
of handle and body (below).

Reliability of an intraoral camera:
Utility for clinical dentistry and
research(jan1984)
 Photographic images can be reliable and efficient
sources of data in dentistry. Many variables can be
investigated from single exposures. This study was
undertaken to test the reliability of an intraoral
graphic instrument— the Orthoscan camera. The utility of
this instrument in clinical orthodontics has been
described, but the research potential has yet to be
investigated.
 Upper and lower dental arches of fifteen patients were
photographed intraorally. Alginate impressions of the
arches were taken immediately afterward. Identical
intertooth distances were located (1) on the intraoral
photographs, (2) on the photographs of the dental casts,
and (3) on the dental casts themselves. Univariate and
multivariate analyses were used to assess measurement
error in these replicate measurements. The camera was
found to be a highly reliable instrument. The images are
flat and free of distortion, with a one-to-one size
relationship. The camera is quite suitable for precise
scientific investigations, and the data are acceptable
for valid interobserver and interpopulation comparisons.www.indiandentalacademy.com

The ideal features of a compact digital
camera can be summarized as follows:
 • Lens system with a high focal length and a powerful zoom, allowing
intraoral photography with at least a magnification comparable to the
1:2 lens of 35mm cameras.
 • Optical resolution of at least 500,000 pixels.
 • Clinically useful resolution of at least 400,000 pixels (depending on
the two previous criteria).
 • Both auto and manual focus.
 • Ability to use a ring flash.
 • Optical reflex viewfinder, or LCD with a high refresh rate.
 • Capability of reviewing the recorded image on the viewfinder screen.
 • Ability to manually tune exposition parameters.
 • Rechargeable batteries and AC connection.
 • External memory that will store an adequate number of images and
speed up file transfer to the computer.
 Features to avoid include:
 • Fixed focal length of 35mm (equivalent to a 35mm camera).
 • Low optical resolution (640 ´ 480 or 300,000 pixels).
 • Galilean viewfinder.
 • Alkaline batteries.
 • Built-in memory only.

Office photographer and
subject, both standing. Base
view. Patient's previous
photographs should be
reviewed and should be on
counter behind
photographer. Camera
synch cord is attached to
closest Multi-blitz Mini-
light. Subject is 2½ feet
from background and 5 feet
from back of camera.

 Biometricians, anthropologists, orthodontists, and others interested in
auxological measurement and research have come to rely on photography.
Photogrammetry has the advantages of immobility and permanence.
Photographs, like radiographs, are efficient sources of data. They provide many
study parameters from a single exposure.
 Until the work of Sheldon1 in the 1940s, photogrammetry was not recognized as
an accurate, reliable, and important technique. Prior to this, a photographic
record was viewed suspiciously because of lighting difficulties, enlargement,
distortion due to paper shrinkage, and nonstandard lens-to-subject distances.2
since the 1940s, published studies on the measurement of the dentition and tooth
position have used a variety of methods. Some investigators have used dividers,
calipers, and Boley gauges,3-5 others have used clear plastic overlays with
standardized markings,6 and some have used xerographic prints and
photographic negatives of dental casts.7-9 The accuracy of these methods usually
improved with improvements in the technology.
 Photographic technology has also improved. Modern intraoral photography has
become an essential tool in dentistry. It can be invaluable in diagnosis, patient
progress, and research. Photography in dentistry can also serve as medicolegal
documentation for patient records. Photographic findings complement and often
exceed written records and radiographs.
 The dentoalveolar complex should be considered in three planes of space. These
planes are the frontal, sagittal, and transverse. Conventional 35 mm single lens
reflex (SLR) intraoral photography can capture occlusal disorders in these spatial
arrangements. To do so, these SLR photographic systems require special lighting
equipment, close-up lens assemblies, sometimes accessories such as mirrors, and
a knowledgeable operator. Excellent systems are available commercially.
However, these systems do not easily generate a one-to-one size relationship or a
straight or orthographic view of the teeth in the transverse plane.
 In the early 1970s, a unique intraoral camera was developed . This is truly an
intraoral camera. The mouthpiece is inserted into the patient's oral cavity and
placed on the occlusal surfaces of the teeth, and a self-illuminated picture is
produced. The camera has gained a moderate degree of popularity in clinicalwww.indiandentalacademy.com

MATERIALS AND
METHODS
Camera specifications
 Fig. 1 shows the Orthoscan II camera and its holding base. This camera has a self-
illuminating light source with a constantly ready power source. This second version is
considerably more portable than the original model. It is cordless, uses three rechargeable
nickel-cadmium batteries, and is stored in the base for recharging when not in use. The
mouthpiece on both models is 6.8 ´ 8.6 cm and 1.27 cm thick. A mouthpiece warmer built
into the holding base minimizes fogging when the mouthpiece is placed intraorally. The
camera itself weighs about 2½ pounds. Production of a picture is simple. Depression of one
button by the operator initiates the photographic process. The camera is equipped with a
Polaroid pack assembly which produces 3 ´ 5 inch black and white or color prints. Prints are
developed external to the camera. The Polaroid 107 black and white prints require 30
seconds for development, while the Polaroid 108 color prints require 60 seconds. There are
eight photographic film prints in each film pack.
 Study sample
 The sample was composed of fifteen patients about to undergo orthodontic treatment. The
upper and lower dental arches of these persons were photographed intraorally. Alginate
impressions of the dental arches were taken immediately after the photographs. The
impressions were poured in white orthodontic stone in a conventional manner and allowed
to set for at least 1 week.
 Anthropologically defined mesial tooth end points11 were located on specified teeth with
India ink dots. The occlusal surfaces of these casts were placed on the camera's mouthpiece
and photographed. Identical mesial tooth end points were then located (1) on the intraoral
photographs (Figs. 2 and 3); (2) on photographs of the dental casts (Figs. 4 and 5); and (3) on
the dental casts themselves. Intertooth measurements were made on anterior (intercanine)
and posterior (intermolar) teeth for each arch. In this manner, there were three groups with
two measurements per arch for fifteen subjects. This produced a total of 90 measurements
per arch across the sample. By including measurements from the anterior and posteriorwww.indiandentalacademy.com

Fig. 1. Orthoscan
camera and holding
base.
Fig. 2. Intraoral photograph of subject's
maxillary arch.

 Note flat blue-green (painted)
wallboard background,
Hunter-Douglas Dwette Eclipal
"total darkness" window shade,
and 8-inch lift. Note optional
indirect Lite Disc Reflector to
provide soft light from below,
directly to chin and front of
face.

DISCUSSION
Reliability in this study refers to the comparison of independent
measurements repeated on the same subject within a short interval of
time. This process is concerned with systematic fluctuations in
measurements— errors. Accidental errors could result from misreading
the instruments or misrecording the readings from those instruments.
Technical errors include poor definitions of landmarks and
inconsistencies in locating defined landmarks. Within-observer
replicates and between-observer replicates are the two methods of
assessing errors that were recommended by Healy.12 The former
method is suitable for studies in which one observer conducts repeated
measurements on many subjects. The latter method is appropriate for
studies in which more than one observer participates. Healy also
recommended the use of analysis of variance to evaluate the data
statistically. In the present study a one-way ANOVA was used as part
of the assessment criteria. The method of within- and between-observer
replicates yielded data on the absolute values and data on the
magnitude and direction of the differences between duplicates.
Considering the size differences of the means listed in Table I, a careful
observer may question the size of the standard deviations. They are
larger than one would expect. Both anterior and posterior intertooth
measurements were purposely included in the same computations. This
was done to capture any overall reflection of distortion in the
photographs. Small discrepancies in the canine and molar regions
would be additive. Over the entire sample differences would bewww.indiandentalacademy.com

 The photogrammetric method presented demonstrates a way of reliably recording defined
anatomic occlusal tooth landmarks. The camera permits the quantification of intra-arch dental
characteristics. The three-dimensional morphology of the teeth and dental arches can be described
in terms of two-dimensional X and Y rectangular coordinates. Data collected in this fashion are
extremely conducive to electronic reduction and computer analysis.
 Clinical uses, such as checking patients' arch form and symmetry and indirect arch wire
fabrication, have been described by Chanda.10 It could be used for fabricating arch wires when
the lingual appliance technique is used. However, the research potential of this camera has yet to
be explored. Generation of statistically relevant interpopulation data could be accomplished quite
cheaply and conveniently. For example, the taxonomic significance of human dental arches has
been documented.13 With this camera, data on the arch size and shape of extant and extinct
populations are easily retrieved. In addition, epidemiologic studies in the field would be greatly
facilitated, standardized information would be obtained. This new method of measurement can
also help collect contemporary data on the growth and development of the dental arches. These
data could be useful in embellishing existing models9,14 which can simulate the effects of
orthodontic treatment on arch growth. The collection of these data would not be wedded to dental
casts. The production of dental casts is labor intensive. Substantial amounts of materials and
laboratory support are essential. The storage and management of these casts can be problematic in
large-scale studies.
 The accuracy of this method is impressive, but certain limitations may render this method
unsuitable for some analyses. The resolution of this camera is static; it cannot be focused. The
camera lacks any sizable depth of field. This is a common limitation with photocopying devices.
Fortunately, distortion or enlargement error is small and constant.7 However, the tracing and.
superimposition of occlusograms could be inaccurate. In cases with pronounced curves of Spee,
pictorial clarity may not be uniform. Investigators interested in measuring the crown components
of posterior teeth, for instance, should not use this instrument. More sensitive methods11,15 must
be employed. Despite this limitation, the intraoral camera is quite versatile. A variety of studies of
tooth and arch dimensions can be derived from single photographic exposures.

 Polaroid CU-5
 With respect to lens, storage of unit, transportation, and simplicity of operation, the
only instant camera system which is now available in complete form is the Polaroid
CU-5.
 The Graphlex prototype, although promising technically, is not yet available
commercially. The modified Model 95 with extended bellows takes only extraoral
black and white photographs. The other camera systems require the fabrication of
holders and framing devices by the practitioner. Since the CU-5 is the first complete
system to be made available, its capabilities and limitations are of interest to the
dental profession. A photograph of the CU-5 is shown in Figure 1.
 This unit is basically a close-up camera of modular design. Two special dental kits
(Fig. 2) are available for 1:1 photography, and for 2:1 use. This unit can be held and
operated with one hand (Fig. 3).
 In this instance, the modules and attachments for 1:1 photography have been
assembled. The modules are locked together with a half turn of the locking wing.
The dental attachments snap into place and are indexed in such a way as to prevent
improper attachment. The exposure system is automatic and may be set for either
black and white or color. For those with special needs the automatic controls can be
easily overridden. The power supply for the built-in electronic flash ring may be
located in any convenient place such as the bracket table. Another suggested
approach is to locate all equipment and accessories on a small wheeled table near
the dental chair. The Polaroid CU-5 is designed to take:
 1. 1:1 intraoral photographs
 4. Extraoral ¼ life size photographs.

 Intraoral photographs are made with either a plastic guard or a reflector. For
this work, the camera system is of a fixed focus design and it is positioned
by an anterior plastic guard. The 1:1 anterior extension fits into the bottom
shoe of the intraoral mount. The camera is held level while the concave edge
of the extension is placed against the recess of the patient's chin. The picture
obtained is approximately life size.
 For palatal or mandibular views, reflectors are attached to the front bracket.
When using reflectors, a sharp focus is achieved by positioning the leading
edge o£ the reflector as close to the last molars as possible. Both the large
and small palatal reflectors fit into the bottom shoe of the intraoral mount.
The picture obtained is a reflected image so that left/right orientation is
reversed. The curved tips of the reflector should just touch the surface to be
photographed. Best results are obtained when the camera is aimed in a line
parallel to the occlusal surface of the teeth being photographed. This places
the reflector at a 45 degree angle to the occlusal plane. The mandibular
occlusal view is taken with the intraoral mount reversed so that the palatal
reflector points downward. Lip retractors are recommended for this view.
 The lateral buccal reflector fits into the side shoe of the intraoral mount. The
mount in turn can be reversed to locate the reflector on the patient's left or
right as desired. This accessory may also be used to take reflected lateral
lingual views. For best results, the curved tip of the reflector should just
touch the rear teeth.
 The reflectors can be sterilized in the same way as other dental instruments.
Fogging of the reflectors can be avoided in several ways. The reflector may
be warmed slightly, anti-foggant may be used, or a jet of air can be directed
at the reflecting surface. In all cases the patient should hold his breath
during the exposure.

 Source: JCO on CD-ROM (Copyright © 1998 JCO, Inc.), Volume 1967
Dec(156 - 163): New Horizons in Intra and Extra Oral Instant Photography -
L. F. QUIGLEY JR., DDS, C. M. COBB III, PhD, J. HEIN, P
 --------------------------------
 With the 1:1 attachments, there are two basic picture-taking methods: one
utilizes mirror reflection both to illuminate and to record the subject (Fig. 4);
the other provides direct photography of the subject (Fig. 5) . With the
addition of a ratio multiplier between the camera body and the lens module,
2:1 photographs can be taken. The images of the 2:1 kit will be
approximately twice lifesize (Fig. 6).
 The two-times anterior extension is used in much the same way as the 1:1
extension except that the curved edge is placed against the tip, not the
recess, of the patient's chin.
 The two-times anterior extension can also be used with the 1:1 camera
assembly for direct lateral lingual and oral pharyngeal views.
 The two-times occlusal reflector fits into the bottom shoe of the intraoral
mount and produces detailed images of selected areas on the occlusal
surface. Correct alignment is achieved by gently resting the corners of the
reflector against the base of the dental arch.
 Use of lip retractors is optional. It is also possible with the CU-5 to take 3:1www.indiandentalacademy.com

fig4

fig5

fig6

 Extraoral photography
 For extraoral photography, a five-inch focal length lens module is mated to
the camera body and a viewfinder is attached to the accessory shoe (Fig. 7).
The CU-5 is particularly well adapted for extraoral photography (Figs. 8 &
9). The viewfinder is of the split image type and is set for 25 inches. In
extraoral photography the least amount of distortion is required. This can be
accomplished by keeping the camera on the same level as the patient. If the
operator is above the patient, this technique will produce extreme distortion
and is to be avoided. In general, it is imperative to have the camera at the
same height as the patient. If very accurate photographs are required, a
tripod or wall bracket should be used. The distance can then be set precisely
at 25 inches.
 As supplied by the manufacturers the CU-5 system produces the flash back
phenomenon; this 'red eye' problem is caused by light being reflected back
to the camera lens by the retina.
 The flash back can be eliminated by using an off axis flash instead of the ring
light. Another method of correcting this problem is by increasing the
ambient light level in the room, thus reducing the size of the pupil. In any
event, the phenomenon is distracting only in color photography.

Fig8 & 9

fig7

Source: JCO on CD-ROM (Copyright © 1998 JCO, Inc.), Volume 1967 Dec(156 - 163): New Horizons in Intra and Extra Oral Instant Photography
- L. F. QUIGLEY JR., DDS, C. M. COBB III, PhD, J. HEIN, P
--------------------------------
Summary
A detailed description has been given of the Polaroid CU-5 since this is the first
complete system made available to the medical and dental professions. Other
systems from other manufacturers will probably become available in time and one
prototype system of this kind has been briefly described (Graflex).
Most workers in orthodontics and research have had considerable difficulty in
obtaining adequate records at the time the patient is examined. By means of
instant processing, film records may be evaluated immediately. The photograph
may be retaken, if necessary, without recalling the patient. Record-taking is a
foundation upon which we must build the diagnosis, prognosis, and evaluation of
our work.(((( Editors of journals in particular must look with a jaundiced eye at the
articles they receive which do not have preoperative and postoperative
photographs of equal quality.))))
With the previously available record-taking equipment and taking into account the
harried life of the average clinician, these mistakes were understandable in the
past. Few dental or medical clinicians have had the time or inclination to become
professional photographers. With the equipment now available, this excuse is no
longer valid.

FINDINGS
 A reliability analysis of the data is presented in Tables I to IV. Table I presents means
and standard deviations for intertooth widths by technique for each dental arch. The
discrepancies in intertooth widths were quite minimal.
 As shown in Table II, there was little variation in maxillary arch widths as assessed by
analysis of variance. The difference between the measurements for any of the
techniques was not statistically significant. Table III presents the ANOVA
computations for the mandibular arch. Again, there was no significant intertechnique
variation .
 Analysis of variance is not the only way in which measurement errors may be
assessed. Another method is correlation. ANOVA computations yield information
about means and variances, while correlation examines the relationships among the
measurement values themselves. By employing both analytical methods, it is possible
to decide whether the three techniques obtained essentially the same results, whether
the values covaried in a systematic way, or both. Table IV presents reliability
coefficients for measurements in both arches. Cronbach's alpha for the maxillary arch
measurements is 0.9952; the alpha for mandibular arch measurements is 0.9984.
Considering that absolute duplication would have a Cronbach's alpha of 1.00, the
findings are impressive.
 The Pearson correlation coefficient matrix for measurements in both arches is
presented in Table V. The results are consistent with the high reliability seen in
previous tables.

Lateral view
. Chin and about
40% of neck
should show. Use
Frankfort
horizontal line
to be sure that
head is level.

oblique view-2
Another oblique
view, showing about
half of subject's
pupil, most of her
upper lashes, and
none of her lower
lashes.

Sketch of ideal head
position for frontal
view.
 A, outer canthus to
superior attachment of
the ear (C-SA line);
B, inter-pupillary
line;
C, encompassing area
(crown to collarbone).
The line from the
outer canthus of the
eye to the hairline is
superimposed over the
C-SA line and is not
specifically labeled
in this diagram.

The CUR, a key factor in the choice of
digital cameras, depends on both the
sensor resolution and the quality of the
optical lens system. A new generation of
compact digital cameras with sensor
resolutions of as many as 1,000,000
pixels are now on the market, but they
have poor optical systems that diminish
their CUR. The CUR also depends on the
needs of the user. If you want to
photograph dental crown anatomy in
detail, you will need a high CCD
resolution and/or a powerful lens
system.

ideal technique --would be to have the subject
illuminated with light parallel to the lens axis, which
currently is impossible technically. The nearest
approximation to such conditions, the ring light, often
produces an undesirable flashback in the lens of the eye.
 In color photography, the subject's eyes appear quite
red, and in black and white photography halos are seen
around the eyes. The flashback in the eyes can be angled
away from the camera to give satisfactory color
reproduction for extra oral work by placing an electronic
flashgun above the camera. This off axis technique is
used by all available units except the Polaroid CU-5.
 Since it is necessary to introduce at least one degree of
obliqueness in the position of the light source to avoid
the flashback phenomenon, special precautions must be
taken to eliminate other aspects of obliqueness in the
lighting. To do this, the light source is placed in the
mid-saggital plane and as close to the lens axis as
possible. This illuminates both sides of the mid-sagittal
plane uniformly and eliminates most of the extraneous
shadows. The supra-axial position of the light source
does cause a slight difference in the intensity of the
illumination from the forehead to the chin. The
physiognomy of the face, however, is such that shadows
from this position are almost nonexistent.

Fig. 3.
Intraoral
photograph
of subject's
mandibular
arch.
Fig. 4. Photograph
of dental cast of
subject's maxillary
arch.
Fig. 5.
Photograph of
dental cast of
subject's
mandibular arch.

Viewfinder
 An optical reflex viewfinder is ideal, because it provides an almost perfect
correspondence between the image seen in the viewfinder and the captured image
under all conditions.
 An alternative is a Liquid Crystal Display viewfinder. The LCD can be as small
as .5", in which case an optical system allows proper magnification with the eye
in close contact with the viewfinder, as with most video cameras .An LCD can
also be a small screen, 1.5-2.5" in diameter, in which case the camera must be
held away from the eye when shooting. Most LCDs have a low “refresh rate”,
meaning that as the camera is moved to frame the best picture, the image in the
viewfinder changes jerkily. Other disadvantages are that an LCD is hard to read
in bright sunlight, and that a large unit consumes a great deal of battery
power.
 Digital cameras with Galilean viewfinders are difficult to use, because in macro
photography the area framed by the viewfinder will be quite different from the
one framed by the lens.
 The space between the outer circle and the center circle will have a fuzzy,
textured look when the photo is out of focus. As the image sharpens the two
circles blend into the background. The center circle is a RANGE FINDER type
focus. Here the image is cut in half. When the image in the top half aligns
with the image in the bottom half the image is in focus. The rangefinder type of
focus aid works better under low light conditions.
LCD viewfinder.LCD viewfinder.
Image shown in LCD screenwww.indiandentalacademy.com

We recommend selecting a camera with a CCD
resolution close to the CUR. Too great a difference
will produce unnecessarily large files and thus
will require more memory and a longer transfer time
to the computer. If the CCD resolution is much
larger than the CUR, it will be necessary to
manipulate (“crop”) each file on the computer to
avoid archiving unwanted information.
The sensor quality of a single pixel in
transmitting the luminance (brightness) and
chrominance (color hue) of the light signal should
be tested by observing the images captured by the
digital camera on a properly tuned monitor. Some
CCDs show a minor shift in hue toward one of the
base colors (red, green, or blue). In our opinion,
this problem has a limited impact on image quality,
since it can be easily corrected with any imaging
software.

 Source: AJO-DO on CD-ROM (Copyright © 1998 AJO-DO), Volume 1997 May (463 - 470): Facial photography for
the orthodontic office George Meredith, MD
 --------------------------------
 MATERIALS AND METHODS
 To obtain the highest quality photographs, the photographer must:
 · Have consistent lighting exposure, focal length, and poses.
 · Use the Frankfort horizontal line on lateral facial photographs.7,9
 · Use 110V AC flash/flood units (Fig. 6).
 · Use a Synch cord between the camera body and one of the 110V AC flash/flood units. The other unit will
trigger at the speed of light (almost) and simultaneously flash. This gives a balanced soft flood/flash lighting effect
on both sides.
 · If the photography room is narrow, use wall mounted flash/flood units (Fig. 6). If the room is wide, then
tripods should be used to mount the flash/flood units (Fig. 7).
 · Be sure that the patient is properly framed and crisply focused.
 · Assure standards for view, framing, and point of focus (Figs. 8 to 13).6 (See Table I.)
 Traditionally, orthodontic pretreatment and posttreatment photographs have used a vertical format. Orthodontists
must be aware of this and standardize their photographic records accordingly. The reader is directed to the work
by Stutts,10 as well as the ABO Handbook,11 that specifically outline the "official position" of the American Board
of Orthodontics regarding facial photography. Nevertheless, it must also be noted that there is a strong movement
in related specialties, notably otolaryngology and plastic surgery, toward the use of a horizontal format
(exclusively). In addition, the photographer must:
 · Include more than just right lateral and frontal (AP) views—left and right oblique views and a base view
should also be included.
 · Insure optimal patient positioning.
 · Insure correct lighting.
 · Avoid parallax distortion.

 Source: AJO-DO on CD-ROM (Copyright © 1998 AJO-DO), Volume 1997 May (463 - 470): Facial
photography for the orthodontic office George Meredith, MD
 --------------------------------
 Previous photographs must be reviewed,3,12 just before taking follow-up photographs, so that
consistent postoperative or posttreatment photographs can be obtained. Most plastic surgery and
otolaryngology scientific program directors not only insist on a horizontal slide format but also
insist on a (fully loaded) Kodak Carousel 80-unit slide tray.
 Kodacolor ASA 100 provides excellent color quality prints. Prints are stored on the patient's chart
and negatives are stored elsewhere in a secure, fireproof box (in case of fire or theft, or other loss).
Slides for scientific presentation can be easily made from color print negatives. Conversely, color
prints made from film for slides requires the use of an intranegative. The increased cost and loss of
crispness are both important factors to consider if slides have to be subsequently converted to
prints for office use, use in the operatory, use in the operating room, or use in scientific
publications. Alternatively, if it is known that these particular photographs are going to be used
for a live scientific presentation, then it is easier and less expensive, in these cases, to use
Kodachrome 64 film for color slides.
 There should be at least 2½ feet between the back of the subject's head and the rear wall to prevent
shadows. A flat nonglare blue-green or medium green background provides for good color prints.
Regardless of the background color used, it must be consistent from year to year. High-quality
color prints are perfectly acceptable for publication (even though they may be published in black
and white, to reduce costs). It is important to aim the flood/flash umbrella or (Photofex) soft box
(Multiblitz Minilite 200) dual flash boxes accurately at the patient. A small electronic portable
flashlight (pointer) taped to the umbrella rod and aimed at the patient facilitates this.
 Central facial distortion is produced with 50 or 55 mm6 and is even more obvious when a 28 mm
lens is used. The best option is the 105 mm facial portrait macrolens. Physicians and dentists
interview patients in their office at distances of 3 to 5 feet. The 105 mm macrolens allows the
photographer to frame the head and neck from 5 feet without parallax problems. To do the samewww.indiandentalacademy.com

Fig. 6. Photographer
holding 35 mm SLR
Minolta X-9 camera
with attached Vivitar
Series I 105 mm
macrolens. Lateral view.
Note left and right side
wall-mounted
Multiblitz Minilight 200
flood/flash units with
umbrellas for soft
indirect lighting.
Patient's previous
photographs should be
reviewed and should be
on counter behindwww.indiandentalacademy.com

 The photographic
protocol:-
-an important aspect of digital
photography.
-increases efficiency and professionalism
-standerised routine photographes.
 A recommended photo sequence is as follows:
1. facial front,(no smiling)
2. Facial front smilimg
3. Right profile
4. Left profile
5. Intraoral central
6. Right buccal
7. Left buccal
8. Upper occlusalwww.indiandentalacademy.com

EXTRAORAL VIEWS:- for the facial shots, the
camera should be positioned in front of the
patient’ head- on the same level as the patient as
well as parellel to floor. Sit the patient in an
upright , comfortable position , about 180 cms
from the camera.
Utilize the digital camera’s preview LCD
monitor and keep the patient’s head in the same
area. If the camera doesnot have the monitor ,
simply utilize the viewing viewfinder (in most
cases, this is more accurate). Utilize the rotational
seating base to turn the patient between shots.

For the closed –lip , the patient should keep the
mouth gently closed, with the teeth togather ans
lips are closed in a neutral , relaxed position.
Pre warn the patient of the flash to minimize the
blinking effect or one can ask the patient to blink
just before u shoot the camera.
For next shot, ask the patient to smile naturally
while keeping the bite closed.
For the facial profile, turn the patient with the
rotating stool. Be sure to shot the patient’s ear
and hairs. The sides of the eyebrow closest to you
should be the only to be visible from the camera
view. The other side eyebrow should not be visible.
This is crucial for lateral profile posture.
A mirror should be present / hang on the wall
facing the patient so that the patient naturally
orient their head position by looking straight into
the mirror.

CENTRAL INTRAORAL VIEW:- are more challenging
than extraoral photograph. To allow optimal
viewing of the dentition, the patient’s lip
must be lifted.
The double ended lip retractors are
recommended to accommodate varying patients
sizes. Two sterilised lip retractors should be
used for central and buccal shot.
While the patient is holding the lip
retractors , assist the patient to gently
insert it into mouth. Then, guide patient to
place the other one on the other side of the
mouth. Ask the patient to bite naturally while
holding the lip retractors still.
Ask the patient to gently pull the retractors
forward to separate the lip from the teeth.
This will provide the best view of the teeth
and arch.
Turn rotating chair to get correct angle for
shot. We can place thumb and forefinger
underneath the patient’s chin to apply gentle
to correct the head psture angle.

Shoot the central view to established a
baseline distance and size, then we
precced with the buccal view.
Just before triggering for buccal view,
quickly and forcibly pull the retractor
towards the ear on the side of the
retractor we are holding. This quick
tuck will give maximum view of
patient’s molar with minimal discomfort
to the patient.

OCCLUSAL VIEWS:- also called as “mirror views”.
Are most difficult of the intraoral shots.
Operator must use an occlusal mirror in order to
capture an acceptable occlusal view of the patient.
Metallic occlusal mirrors with dual ends to
accommodate large and small mouth are recommended .
Can also use mirror warmer such as an electric
blanket, to minimize fogging by placing the mirror
on the blanket prior to the shot.
The occlusal views typically require a slightly
lower aperture.
Optimal placement of the retractors are ten o’clock
and two o’clock position for the upper occlusal and
eight o’clock and four o’clock position for the
lower occlusal. Ask the patient to bends the necks
back as far as possible and looking at the ceiling.
Position he mirror on the arch so atleast the first
molar can be seen in the mirror.

Aim of the camera should be virtually
perpendicular to the that of the surface
of the mirror . The entire arch should be
within the camera lens. Just prior to
capturing the photo it is advisable to
remind the patient to keep the mouth open
wide. To further minimize fogging of the
mirror, ask the patient to breath in and
hold that posture as operator capture the
image.

Viewpoint distortion caused by
a 35 mm wide-angle
lens The camera-to-
subject distance
was diminished,
causing distortion.
B, Viewpoint
distortion caused
by 300 mm telephoto
lens. The camera-
to-subject distance
was increased,
causing compression
distortion.

Digital Photography
Digital imaging, one of the hot fields
in the computer world, is attracting
more and more interest among
orthodontists. It is now possible, with
a reasonable investment, to digitally
acquire, archive, and easily retrieve
clinical images of our patients.
The hardware involved includes flatbed
scanners, slide scanners, video cameras,
and still digital cameras. Digital
cameras can be divided into two main
groups: compact digital cameras and
professional reflex cameras with digital
interface.

Optical System Quality for
Macrophotography(Nov1998)
 For intraoral photography, the lens system should allow adequate magnification
at a distance of at least 12" from the subject. Shorter distances are of little use to
the orthodontist. The optical quality depends on the camera’s focal length—the
distance (in millimeters) between the image sensor and the optical center of the
lens when the lens is focused on infinity.
 Many compact digital cameras have lens systems with a focal length of 35mm
(equivalent to a 35mm camera). This value is inadequate for orthodontic
intraoral photography. A 50mm focal length is sufficient, but a 100mm focal
length will completely satisfy the requirements for dental photography. A high
focal length allows a reasonable distance from the subject, minimizes distortion,
increases depth of field, and permits adequate illumination of the subject.
 Cameras with a zoom function have a variable focal length, which is expressed
as a range. Focal length can be increased with a zoom lens or by the addition of
close-up lenses. The best digital cameras have a zoom with a high magnification
ratio and the ability to add close-up lenses.
 When the zoom is moved toward the maximum enlargement position, or close-up
lenses are added, it can become impossible to focus from short distances, and the
effectiveness of the autofocus is reduced. Thus, you may see an image in the
viewfinder that has a high magnification, but is out of focus. The balance of
these factors is what determines the macro capabilities of the system.

1:2 magnification with 35mm
camera: 70mm line corresponds to
horizontal dimension of film.
We consider the macro quality of a digital
camera to be acceptable when it is possible to
capture a 70mm horizontal line at full screen,
in sharp focus, from a distance of 12". This
corresponds roughly to the 1:2 magnification on
a conventional 35mm camera—one of the most
common magnification ratios in orthodontic
photography.

Auto-focus Speed and Precision
A satisfactory auto-focus for orthodontic
purposes will work properly at a distance
of 12" from the subject with a 1:2
magnification ratio.

Clinical phototgraphy

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