Intraoral radiographic techniques/prosthodontic courses

INTRA ORAL RADIOGRAPHIC
TECHNIQUES
1. INTRA ORAL PERIAPICAL RADIOGRAPHY
2. BITEWING RADIOGRAPHIC TECHNIQUE
3. OCCLUSAL VIEW RADIOGRAPHIC
TECHNIQUE
4. LOCALIZATION TECHNIQUE
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X-RAY FILM
• COMPOSITION
• It has 4 principal components.
1.Film base
2.Adhesive layer
3.Film emulsion
4.Protective layer

X RAY FILM SIZE
• SIZE-0 : 22X35mm in children
• SIZE-1 :24x40mm for anteriors in adults
• SIZE-2 :31X41mm standard size

INTRAORAL FILM SPEED
• Film speed refers to amount of radiation
required to produce a radiograph of standard
density
• An alphabetical classification system is used
to identify film speed
• Speed ratings ranging from A speed [slowest]
to F speed [fastest]
• Only D speed and E speed film is used for
intra oral radiograph.

INTRA ORAL PERIAPICAL
RADIOLOGY
• Periapical radiography describes intra oral
techniques designed to show individual teeth
and the tissues around the apices . Each film
shows two to four teeth and provides
detailed information about the teeth and
surrounding alveolar bone

• Detection of infection and pathoses
• Assessment of periodontal status , state of
periodontal membrane space and lamina
dura
• After trauma to the teeth and associated
alveolar bone
• Assessment of presence and position of
unerupted teeth
INDICATIONS

• Assessment of root morphology , before
extractions
• During endodontics
• Preoperative assessment and post operative
appraisal of apical surgery
• Detailed evaluation of apical cysts and other
lesions with in alveolar bone
• Assessment of position and prognosis of
implants

• There are two basic techniques for obtaining
periapical radiographs:
• Paralleling technique.
• Bisection of the angle technique.
• The American Academy of Oral and Maxillofacial
Radiology and the American Association of Dental
Schools recommended the use of the paralleling
technique because it provides the most accurate
image.
Periapical RadiographyPeriapical Radiography

The Full Mouth Survey
• An intraoral full mouth examination is composed of
both periapical and bite-wing projections.
• On the average adult, a full mouth series consists of
18 to 20 films.
• An ideal full mouth set consists of 21 films.

Mounted full mouth series

The basic principles of projection geometry
• 1.The focal spot should be as small as
possible
• 2.The focal spot to object distance should be
as long as possible
• 3.The object to film distance should be as
small as possible
• 4.The long axis of object and film should be
parallel
• 5.The X ray beam should strike the object and
film planes at right angleswww.indiandentalacademy.com

• Film placement: Position the film so that it will cover the
teeth.
• Film position: Position the film parallel to the long axis of the
tooth. The film in the film holder must be placed away from
the teeth and toward the middle of the mouth.
• Vertical angulation: Direct the central ray of the x-ray beam
perpendicular to the film and the long axis of the tooth.
• Horizontal angulation: Direct the central ray of the x-ray
beam through the contact areas between the teeth.
• Central ray: Center the x-ray beam on the film to ensure that
all areas of the film are exposed.
The Paralleling Technique/Right angle/LongThe Paralleling Technique/Right angle/Long
Cone TechniqueCone Technique

Positions of the film teeth and central ray of the x-ray beam in
the paralleling technique.
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The x-rays pass through the contact areas of the
premolars

Exposure Sequence
• When exposing radiographs, establish an
exposure sequence, or definite order for
periapical film placement.
• Without an exposure sequence, there is a good
chance that you will omit an area or expose the
same area twice.

Anterior Exposure Sequence
• When exposing periapical films with the
paralleling technique, always start with the
anterior teeth (canines and incisors) because:
• The number 1 size film used for anteriors is small,
less uncomfortable, and easier for the patient to
tolerate.
• It is easier for the patient to become accustomed
to the anterior film holder.
• The anterior film placements are less likely to
cause the patient to gag.
As recommended by the American Academy of Oral and Maxillofacial Radiology and the
American Association of Dental Schoolswww.indiandentalacademy.com

Anterior Exposure Sequence− cont’d
• Begin with the maxillary right canine (tooth 13).
• Expose all of the maxillary anterior teeth from right to left.
• End with the maxillary left canine (tooth 23).
• Next, move to the mandibular arch.
• Begin with the mandibular left canine (tooth 33).
• Expose all of the mandibular anterior teeth from left to right.
• Finish with the mandibular right canine (tooth 43).

Posterior Exposure Sequence
• After completing the anterior teeth, begin
the posterior teeth.
• Always expose the premolar film before the
molar film because:
• Premolar film placement is easier for the patient
to tolerate than molar film placement.
• Premolar exposure is less likely to evoke the gag
reflex.

Tips for Film Placement
• The white side of the film always faces the teeth.
• The anterior films are always placed vertically.
• The posterior films are always placed horizontally.
• Always position the film holder away from the teeth
and toward the middle of the mouth.
• Always center the film over the areas to be
examined.
• Always place the film parallel to the long axis of the
teeth.

Preparation Before Seating the Patient
• Prepare the operatory with all infection control barriers.
• Determine the number and type of films to be exposed.
• Label a paper cup with the patient's name and the date.
• Turn on the x-ray machine and check the basic settings.
• Wash and dry hands.
• Dispense the desired number of films and store them
outside of the room in which the x-ray machine is being
used.

Positioning the Patient
• Seat the patient comfortably in the dental chair, with the
back in an upright position and the head supported.
• Ask the patient to remove eyeglasses and bulky earrings.
• Have the patient remove any removable prosthetic
appliances from his or her mouth.
• Position the patient with the occlusal plane of the jaw being
radiographed parallel to the floor when the mouth is in the
open position.
• Drape the patient with a lead apron and thyroid collar.
• Wash and dry hands and put on clean examination gloves.

Types of film holders
SNAP-A-RAY FILM HOLDER
PRECISION FILM HOLDER
Rinn XCP FILM HOLDERwww.indiandentalacademy.com

FILM HOLDERS
ADVANTAGES
• Avoid exposure of patients
finger and are essential in
paralleling techinque
DISADVANTAGES
• The film sometimes cannot
extent far enough beyond
the apical region to allow
examination of periapical
tissues

Maxillary Cuspid RegionMaxillary Cuspid Region
Image field : Should demonstrate the entire canine. Open the mesial contact, ignore the distal contact
region
Film placement : Orient film packet with its anterior edge at the middle of the lateral incisor

• Projection of central ray : Through the mesial contact of the canine
• Point of entry : Through the intersection of the distal and inferior
borders of the ala of the nose

Maxillary lateral IncisorMaxillary lateral Incisor
Image field : Should demonstrate the lateral incisor with its periapical area.
Film placement : Orient film packet parallel to the long axis of the lateral incisor

• Projection of central ray : Through the middle of the lateral incisor.
• Point of entry : On the lip about 1 cm away from the midline

Maxillary central incisor
• Image Field : Both central incisors and their periapical areas
• Film Placement : About the level of the second premolars or molars with long axis parallel to the long
axis of the central incisors.

• Projection of central ray : Trough the contact point of the central incisors
and perpendicular to the plane of the film and the roots of the teeth with a
mild vertical angulation owing to the inclination of the teeth
• Point of entry : High on the lip in the midline just below the septum of the
nostril

Mandibular Cuspid RegionMandibular Cuspid Region
• Image field : Image should show the entire mandibular canine and its periapical area
• Film placement : As far lingually as the tongue would permit with long axis parallel to the
canine.

• Projection of central ray : Direct the central ray through the mesial contact of the canine.
• Point of entry : Perpendicular to the ala of the nose over the position of the canine and about 3 cms
above the inferior border of the mandible.

Mandibular Centrolateral ProjectionMandibular Centrolateral Projection
• Image field : Image should show the central and lateral
incisors and their periapical areas
• Film placement : As far posteriorly as possible usually
between the premolars.

• Projection of central ray : Direct the central ray through the
interproximal space between the central and lateral incisors.
• Point of entry : Below the lower lip about 1 cm lateral to the midline.

Maxillary Premolar RegionMaxillary Premolar Region
• Image field : Image should show the distal half of the
canine ,the premolars extending upto a part of the second
molar
• Film placement : The film is placed extending from the distal
half of the canine with the plane of the film parallel to the long
axis of the premolar www.indiandentalacademy.com

• Projection of central ray :The beam should pass between the
interproximal areas between the first and 2nd
premolars
• Point of entry : At the intersection of the line drawn down from the
pupil to the line drawn horizontally from the ala of the nose.

Maxillary Molar Region
• Image field : Image should show the distal half of the 2nd
premolar , the molars and the region of the tuberosity.
• Film placement : The film is placed as far posteriorily as
possible.

• Projection of central ray :The beam should pass at right angles to
the buccal surfaces of the molars
• Point of entry : On the cheek below the outer canthus of the eye on
the zygoma

Mandibular Premolar Region
• Image field : Image should show the distal half of the canine ,
the premolars and the first molar with the periapical area.
• Film placement : The film is placed with its anterior border
at the midline of the canine and parallel to the long axis of the
premolars

• Projection of central ray :The beam should pass through the contact
points between the two premolars
• Point of entry : On the imaginary line drawn down from the pupil of
the eye 3 cms above the inferior border of the mandible

Mandibular Molar Projection
• Image field : Image should show the distal half of the 2nd
premolar with the molars and the periapical area.
• Film placement : The film is placed with its anterior border
at the premolar and parallel to the long axis of the molars

Point of entry
Projection of the central ray

The Bisecting Technique
• The bisection of the angle technique is based
on a geometric principle of bisecting a triangle
• The angle formed by the long axis of the teeth
and the film is bisected, and the x-ray beam is
directed perpendicular to the bisecting line.

PID Angulations: Bisecting Technique
• In the bisecting technique, the angulation of
the PID is critical.
• Angulation is a term used to describe the
alignment of the central ray of the x-ray
beam in the horizontal and vertical planes.
• Angulation can be changed by moving the
PID in either a horizontal or vertical direction.

Horizontal Angulation
• Horizontal angulation refers to
thepositioning of the tubehead and dire ction
of the central ray in a horizontal, or side-to-
side, plane.
• The horizontal angulation remains the same
whether you are using the paralleling or
bisecting technique.

CORRECT ANGULATION
INCORRECT ANGULATION

VERTICAL ANGULATION

If the vertical angulation is to too steep, the image on
the film is shorter than the actual tooth.

If the vertical angulation is to too flat, the image on
the film is longer than the actual tooth.

Film Size and Placement
• In the bisection technique, the film is placed
close to the crowns of the teeth to be
radiographed and extends at an angle into
the palate or floor of the mouth.
• The film packet should extend beyond the
incisal or occlusal aspect of the teeth by
about 1
/8 to 1
/4 inch.
• Film holders for the bisection of the angle
technique, including some with alignment
indicators, are available commercially.

Beam Alignment
• The x-ray beam is directed to pass between the
contacts of the teeth being radiographed in the
horizontal dimension, just as it does in the paralleling
technique.
• The vertical angle, however, must be directed at 90o
to
the imaginary bisecting line.
Maxillary Mandibular
Incisors +40 degrees - 15 degrees
Canines + 45 degrees - 20 degrees
Premolars + 30 degrees - 10 degrees
Molars + 20 degrees - 5 degrees

Maxillary canine exposure.

Maxillary incisor exposure.

Mandibular canine exposure.

Mandibular incisor exposure.

Maxillary premolar exposure.

Maxillary molar exposure.

Mandibular premolar exposure.

Mandibular molar exposure.

ADVANTAGES OF PARALLELING
TECHNIQUE OVER BISECTING
ANGLE TECHNIQUE
• Geometrically accurate image are produced
with little magnification and maximum
sharpness of the image
• The shadow of zygomatic bone does not
appear above the apices of the molar teeth
[no superimposition of normal anatomical
land marks over molar roots ]
• The horizontal and vertical angulations of the
[xray tube head] are automatically
determine by positioning deviceswww.indiandentalacademy.com

• Reproducible radiographs are possible at
different visits and with different operators
• The teeth is more standardised so it can be
used in reasearch work
• There is no exposure of the patients fingers
during radiography

DISADVANTAGES
• The anatomy of mouth sometimes makes the
technique difficult in all parts of mouth since
target film distance is increased according to
inverse square law the time of exposure is
increased as intensity of rays is decreased
• Needs a long cone and also needs special
equipment as the film holders.

DIFFERENCES B/W BISECTING
ANGLE AND PARELLELING
TECHNIQUE
BISECTING ANGLE
• Short cone is used
• Film is contact with the
crown of tooth 2 mm below
incisal edge/occlusal
surfaces
• It is held by patients finger
• Vertical angulations are
different according to
position
PARALLELING TECHNIQUE
• Long cone is used
• Film is placed parallel to the
teeth and not in contact
with crown beyond film
holder
• It is held by film holders
• Vertical angulations zero

• Central ray is perpendicular
to bisector
• Beam of rays are divergent
• Time and simplicity are
quick and simple
• Central ray perpendicular to
teeth
• Beam of rays are almost
parellel
• It is needs time and is
complicated

Bite-wing Examinations
A bite-wing radiograph shows the crowns and
interproximal areas of the maxillary and mandibular
teeth and the areas of crestal bone on one film.
• Used to detect :
• Interproximal caries ; Secondary caries below
restorations; Evaluation of periodontal condition;
Crestal bone level; Calculus deposits in
interproximal areas; Height of the pulp chamber

The Occlusal Technique
• The occlusal technique is used to examine
large areas of the upper or lower jaw.
• In the occlusal technique, size-4 intraoral film
is used. The film is so named because the
patient bites, or “occludes,” on the entire
film.
• In adults, size-4 film is used in the occlusal
examination.
• In children, size-2 film can be used.

Object Localization with intraoral
radiography
• In 1909, Clark reported a radiographic procedure
for the localization of impacted teeth.
• In 1953 , buccal object rule – a modification of
the clark’s rule.

Same – Lingual
Opposite -
Buccal

REFERENCES
1. Oral Radiology Principles and Interpretations –
White and Pharoah edition 5.
2. Dental radiology principles and techniques-joen
iannucci harring edition 2.

Intraoral radiographic techniques/prosthodontic courses

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