Technique of dental radiographic

Technique of Dental Radiographic
Yashawant ku. Yadav
B.MIT 1 𝑠𝑡
year
Roll no. 06
NAMS -Bir Hospital1

Overview
Introduction
Equipment's used
Dental radiographic film type
Anatomy of teeth
Terminology
Types of dental x ray
References
2

Introduction
• Dental radiographs are commonly called X-rays. Dentists
use radiographs for many reasons to find hidden dental structures,
malignant or benign masses, bone loss, and cavities.
• Dental caries, infections and other changes in the bone density, and
the periodontal ligament, appear darker because X-rays readily
penetrate these less dense structures. Dental restorations (fillings,
crowns) may appear lighter or darker, depending on the density of the
material.
• The dosage of X-ray radiation received by a dental patient is typically
small (around 0.150 mSv for a full mouth series, according to the
American Dental Association website).
3

Contd..
5
 X ray tube potential:-
• Not lower than 50kVp and recommended
is 60-70kVp
 X-ray tube filtration: -
• 1.5mm aluminum equivalent for up to
70kVp and 2.5mm for more than 70kVp.
 X-ray beam dimensions:-
• Beam diameter at the patient’s skin not
greater than 60mm.
 Minimum focus-to-skin distance:-
• 200mm for 60kVp or, grater and
100mm for less than 60kVp

Dental Radiographic Film Types
• There are two main types of dental x-rays
intraoral (the x-ray film is inside the mouth)
and extra oral (the x-ray film is outside the
mouth).
• Intraoral x-rays are the most
common type of x-ray. There are
several types of intraoral x-rays. Each shows
different aspects of teeth.
6

Dental radiographic film types:-
• Intra-oral radiography: –
- direct or non-screen film
-digital receptors.
• Extra-oral radiography: –
- film-screen
- digital receptors: (storage
phosphor and solid-state).
7

Intra-oral film sizes:-
• Size 0 -22 *35mm: used for small children and anterior periapical using
the paralleling technique.
• Size 1 - 24 * 40mm: used for bitewings in small children and also for
anterior projections in adults. Not available routinely in the our
department .
• Size 2 - 31 * 41mm: used for bitewings in adults and older (generally
six years plus) children and periapical projections. Can be used for
occlusal views in young children.
• Size 4 -57 * 76mm: used for occlusal projections of the maxilla and
mandible.
8

Dental digital receptors :-
The two methods of image capture used are solid-state and storage
phosphor:
 solid-state: These include charge-coupled device (CCD), charge-
injection device (CID) and complementary metal oxide
semiconductor (CMOS)based sensors. The sensor is linked directly
to the computer via a cable. There is an instantaneous image
display with these systems.
 storage phosphor: These systems are commonly found in general
radiography departments and may be referred to as computed radiography
(CR). Other terms used to describe the technique are photostimulable
phosphor radiography (PPR), storage phosphor radiography (SPR) and
photostimulable phosphor (PSP). The PSP imaging plates consist of
europium activated barium fluorohalide.
9

Advantages and disadvantages of solid-state and storage
phosphor
10
Advantages Disadvantages
• Almost instant images , negligible delay
of 20s as the plate is read by the laser.
• Cost
• image manipulation • In some solid-state systems, the sensor
may have a smaller sensitive area than the
film, requiring more exposures to the
cover area of interest
• very wide exposure latitude
• sensors are identical in size and thickness
to the film and are tolerated well by
patients
• some imaging systems provide
insubstantial intra-oral positioning
devices.

Anatomy of Teeth
11
• The anatomic crown of a tooth is the area
covered in enamel above the cement enamel
junction (CEJ) or "neck" of the tooth.
• Most of the crown is composed of dentin
with the pulp chamber inside.
• The crown is within bone
before eruption. After eruption, it is almost
always visible.
• The anatomic root is found below the CEJ
and is covered with cementum. As with the
crown, dentin composes most of the root,
which normally has pulp canals.

Contd..
• A tooth may have multiple roots or just
one root (single-rooted teeth).
• Canines and most premolars, except
for maxillary first premolars, usually
have one root.
• Maxillary first premolars
and mandibular molars usually have
two roots.
• Maxillary molars usually have three
roots. Additional roots are referred to
as supernumerary roots.
12

Dental formulae and notations
-There are several internationally recognized methods of
identifying the teeth that require radiography.
The two most commonly used methods of notation are:-
• Palmer notation and
• Fédération Dentaire International (FDI) notation.
Deciduous teeth :-212/212
Permanent teeth:-2123/2123
13

Palmer notation
14
• The Palmer notation is depicted
schematically, with a vertical line between
the central maxillary and mandibular
incisors and a horizontal line between the
maxilla and mandible, dividing the oral
cavity into quadrants.
• The clinician requesting intraoral
radiography uses these vertical and
horizontal lines to denote the quadrant to
which the tooth/teeth to be radiographed
belong.

Contd..
To avoid confusion between the permanent
and deciduous dentition, the following
convention is observed:-
•For the deciduous dentition: five teeth in
each quadrant are assigned the letters A–E,
from the central deciduous incisor to the
second deciduous molar, respectively.
•For the permanent dentition: Eight teeth
in each quadrant are assigned the numbers
1–8, from the central incisor to the third
permanent molar, respectively
15

Contd..
Examples of requests for dental examinations using this system are:-
16

Federation Denature International notation
• The dentition is again divided into four
quadrants.
• These are assigned the numbers 1–4 for
the permanent teeth and the numbers 5–8
for the deciduous dentition.
• In both dentitions, the quadrants follow
on numerically, starting from the upper
right, to the upper left, to the lower left
and, finally, to the lower right.
17

Contd..
• Examples of requests for dental examinations using this formula are:
53 – upper right deciduous canine.
37, 38 – lower left second and third molars.
18

Terminology
• Mesial :-represents that surface of the tooth adjacent to the median
plane following the curvature of the dental arch.
• Distal:- represents that surface of the tooth furthest away from the
median plane following the curvature of the dental arch.
• Lingual or palatal :-refers to the inner aspect of the teeth or dental
arches adjacent to the tongue or palate, respectively.
• Buccal or labial :-refers to the outer aspect of the teeth or dental
arches adjacent to the cheeks or lips, respectively.
• Occlusal:- refers to the biting surface of both premolar and molar
teeth.
• Incisal:- refers to the horizontal flat surface of the incisor teeth.
19

Contd..
•Alveolar crest – Highest part of the alveolar bone.
•Alveolar ridge – Part of the bone that contains the tooth
sockets
•Edentulous – Without teeth.
•Foramina – Plural for foramen; an opening.
•Interproximal – Between the teeth.
•palatal – The roof of the mouth.
• periapical – Surrounding the apex or tip of the tooth.
•periodontal – Surrounding the tooth.
20

Contd..
• periodontal disease – Disease of the gums and supporting areas of the
teeth.
21

Occlusal planes
22
The occlusal plane is the plane that passes through the
opposing biting surfaces of the teeth. The terms upper
occlusal plane and lower occlusal plane are used in
radiographic positioning when carrying out intra-oral
radiography.

Types of Dental Radiography
Dental radiography is classified in to
two types :-
1. Bitewing
2. Periapical
Bitewing :- Bitewing radiography
requires that the beam, in the
horizontal plane, meets the teeth and
the film at right-angles and passes
through all the contact areas.
23

Indications For Bitewing Radiography
• The detection of dental caries in the upper and lower premolar and
molar teeth
• Monitoring the progression of dental caries
• Assessment of existing restorations
• Assessment of the periodontal condition.
• To determine the relation of tooth to the occlusal plane for possibility
if tooth ankylosis.
• To understand the configuration of pulp chamber.
24

Position of patient
• The correct film size is chosen and the bitewing tab
is attached. Normally adult a size 2 film
(31*41mm) ,And in children size 0 film
(22*35mm) is used.
• Place the film in the lingual sulcus.
• The anterior edge of the film should be located
opposite to the distal aspect of the lower canine.
• The tab rests on the occlusal surface of the lower
teeth.
• The patient is told to bite gently on the tab and,
when the teeth are almost in contact, the operator
pulls the tab laterally to ensure that there is good
contact between the film and the teeth. 25

Direction and centering of the X-ray beam
• The tube is angled five to eight degrees
downward (caudad) with the central ray
at the level of the occlusal plane and
perpendicular to the contact points of
the teeth.
Position of patient and film
using a bitewing film-
holding/beam-alignment
instrument:- 27

Periapical radiography
For periapical radiography, two
techniques have been developed :-
• Bisecting angle technique: this is
based upon the geometric theorem of
isometry. It requires the central ray of
the X-ray beam to pass through the
root of the tooth at right-angles to a
plane that is the bisector of the angle
formed by the long axis of the tooth
and the plane of the film.
28

Contd.
• Paralleling technique: this requires that
the X-ray film is positioned parallel with
the long axes of the teeth or tooth to be
imaged.
• This enables the central ray of the X-ray
beam to pass at right-angles, i.e.
perpendicular, to the beam to the long axes
of the teeth and the plane of the film.
29

Indications
• Assessment of apical pathology and other lesions situated within
alveolar bone.
• Pre- and postoperative assessment of alveolar surgery.
• Following trauma to teeth and alveolar bone.
• Localization of teeth and presence/absence of teeth.
• Before extraction to assess root morphology and the relationship of
roots to vital structures, i.e. the inferior dental canal, the maxillary
antrum.
• During endodontic therapy(root canal therapy).
• Pre- and postoperative assessment of implants.
30

Bisecting angle technique (contd..)
The convention for intra-oral film placement is as follows:-
• Anterior teeth (incisors and canines): long axis of film vertical.
• Posterior teeth (premolars and molars): long axis of film horizontal.
The patient’s head must be supported adequately with the medial plane
vertical and the occlusal plane horizontal (i.e. upper occlusal plane and
lower occlusal plane for maxillary and mandibular radiography,
respectively).
33

Contd..
If a film holder is used If the patient’s finger is used:
Position the film holder intra-orally adjacent to
the lingual/palatal aspects of the tooth/teeth to
be imaged
Ensure that the tooth/teeth being
examined are in the middle of the film
Insert a cotton-wool roll between the
opposing teeth and the bite block
2mm of the film packet should extend beyond
the incisal or occlusal margin to ensure that the
entire tooth is imaged
Ask the patient to close together slowly
to allow gradual accommodation of the
film holder intra-orally.
Instruct the patient to gently support the
film using either their index finger or
thumb.
Tell the patient to continue biting on the
bite block to position the film holder
securely
Apply the patient’s finger/thumb solely
to the area of film that overlies the crown
and gingival tissues of the teeth. 34

• The X-ray beam should be
centered vertically on the
midpoint of the tooth to be
examined.
• It is important to remember that
proclined teeth will require more
angulation, whilst retroclined
teeth will need less angulation.
• The X-ray tube must be
positioned so that the beam is at
right-angles to the labial or buccal
surfaces of the teeth to prevent
horizontal overlap 35

Paralleling technique
• The paralleling technique requires that
the X-ray film is positioned parallel
with the long axis of the teeth. The
central ray of the X-ray beam passes at
right-angles, i.e. perpendicular, to the
tooth.
• In order to minimize magnification of
the image and subsequent loss of image
sharpness, the technique uses an
increased focal spot-to-object distance,
ensuring that a more parallel X-ray
beam is incident to the object and
image receptor. 38

Contd..
Advantages Disadvantages
Minimal
elongation/foreshortening/distortion
The paralleling technique can be
used when using X-ray equipment
with a short FFD (less than 20cm)
providing the operator accepts
increased magnification
Increased focus-to-skin distance
(FSD) reduces surface dose
Increased FSD improves image
quality by reducing the penumbra
effect
Anatomical limitations, such as a shallow
palate, principally in the maxillary molar
and anterior regions, preclude true parallel
placement of the film relative to the tooth.
Reduction in distortion effects due to
bending of the film/image receptor 39

Position of patient and film
• The appropriate film holder and periapical film are selected and
assembled.
• Place the bite block in contact with the edge of the tooth to be imaged.
Ensure that the film covers the particular tooth/teeth to be examined.
 Maxilla: –
• For the incisor, canine, premolar and molar regions, the film holder
must be positioned some distance from the tooth to achieve parallelism.
• This requires using the entire horizontal length of the bite block with
the film holder occupying the highest part of the palate.
40

Contd..
Mandible: –
• For the lower incisor teeth, position the film holder in the plane of an
imaginary line intersecting the first mandibular premolars or as
posterior as anatomy will allow.
• For the mandibular premolars and molars, position the film holder in
the lingual sulcus adjacent to the teeth selected for imaging.
42

43

Essential image characteristic
• There should be no evidence of bending of the teeth and the periapical
region of interest on the image.
• There should be no foreshortening or elongation of the teeth.
• Ideally, there should be no horizontal overlap. If overlap is present,
then it must not obscure the pulp/root canals.
• The film should demonstrate all the tooth/teeth of interest (i.e. crown
and root).
• There should be 3mm of periapical bone visible to enable an assessment
of apical anatomy.
• There should be good density and adequate contrast between the enamel
and dentine.
• There should be no pressure marks on the film and no emulsion
scratches 44

Third molar region
• Surgical haemostats/needle holders can be
used to stabilize the film.
• The upper leading anterior edge of a size 2
film is attached securely to the beaks of
the needle holder, ensuring that the front
aspect (or imaging surface) will face the
X-ray tube when positioned intra-orally.
• The film is positioned in the lingual sulcus
as far posteriorly as possible.
• The patient is instructed to hold the
handles of the needle holder. 45

• The tube is centered and angulated as outlined in the above table for
the mandibular molar region.
• The X-ray tube must be positioned so that the beam is at right-angles
to the labial or buccal surfaces of the teeth to prevent horizontal overlap,
and the film is exposed.
46

Occlusal radiography
Occlusal projections are used to image relatively large areas of
the dental arches
• True (Cross sectional/axial/plan)
-Vertex Occlusal, Floor of mouth ,
-Mandible-Midline, Anterior, Posterior
Oblique
• Maxilla- Anterior ,Midline, Posterior
• Mandible ,anterior
• Lower oblique 48

Indications
-To localize accurately
-Unerupted teeth,
-Retained roots,
-Odontomas(benign tumor of tooth development),
-Foreign bodies,
-Radio-opaque salivary calculi, etc.
-To evaluate a patient with severe trismus or who cannot tolerate
periapical radiography
- To evaluate the medial-lateral extent of pathology, e.g. cysts, tumors,
malignancy, osteodystrophy's
49

Vertex occlusal of the maxilla
• It requires the use of an intra-oral
cassette with
• rare-earth intensifying screens to
reduce the dose to the patient.
• This projection shows a plan view of
the maxillary teeth and is used to
demonstrate the Bucco-palatal
relationship of unerupted teeth in the
dental arch.
50

Position of patient and cassette
• The patient sits comfortably, with the head supported. The median
plane is vertical and the occlusal plane is horizontal .
• The cassette should be placed flat in the patient’s mouth, adjacent to the
occlusal surface of the lower teeth.
• Position the cassette as far back as possible, at least to the level of the
first permanent molars.
• The patient should bite together gently to stabilize the cassette intra-
orally.
51

• The tube is positioned over the vertex of the skull, and the central ray is
directed along the median plane downward (caudad) through the long
axis of the upper central incisor teeth
52

True occlusal of the mandible (submental occlusal)
• This projection shows a plan view of the
mandible, with the teeth and the lingual
and buccal cortices seen in cross-section.
The occlusal film should be placed as far
back in the mouth as the patient will
tolerate, with the film resting on the
occlusal surfaces of the lower teeth. The
tube side of the film faces the floor of the
mouth with the long axis of film
extending across the oral cavity (i.e.
perpendicular to the sagittal plane). 53

Contd..
• The anterior leading edge of the film
should extend 1 cm beyond the labial
aspects of the mandible incisor teeth.
• The patient is instructed to extend
their head backwards so that the ala-
tragus line is almost perpendicular to
the floor. The head is then supported
adequately in this position.
• The patient should bite together
gently to avoid pressure marks on the
film.
54

• The tube is placed well down below the patient’s chin and directed
vertically at 90 degrees to the occlusal plane and the film.
• Centre the tube in the midline at 90 degrees to an imaginary line joining
the first permanent molars (i.e. 3 cm distal to the midline of the chin).
55

Occlusal radiography additional views
•Oblique occlusal of the maxilla
•Midline occlusal
•Anterior oblique occlusal
•Posterior oblique occlusal
56

Oblique occlusal of the maxilla
• The projection is used to show the anterior
maxilla.
The tube is positioned above the patient in
the midline and angled downwards
(caudad) at 65–70 degrees, the central ray
passing through the bridge of the nose
towards the center of the film
57

Anterior oblique occlusal
• This projection is used to image the
anterior region of the maxilla. The
tube is centered over the
lateral/canine region and is
commonly
Direction and centering of the X-
ray beam
• The centering point is the bridge of
the nose with downward (caudal)
angulation of 60 degrees.
59

Posterior oblique occlusal
• This projection demonstrates the posterior
quadrant of the maxillary arch, the teeth,
the alveolar bone and part of the maxillary
antrum, the floor of the antrum and the
zygomatic process of the maxilla
superimposed over the roots and crowns of
the molar teeth.
Direction and centering of the X-ray
beam
The centering point is medial to the outer
canthus of the eye but level with the pupil. It
is important to ensure that the central ray is
at right-angles to the dental arch.
60

lower oblique occlusal of the mandible
• This projection demonstrates the
soft tissues of the middle and
posterior aspects of the floor of the
mouth.
Direction and centering of
the X-ray beam
• The X-ray tube is positioned 2 cm
below and behind the
• angle of the mandible.
• 115 degrees cephalad
61

Alternative view of mandible oblique
• Head is rotated with the
affected side 20 degrees away
from the table.
• The X-ray tube is positioned
above and tube position 25
degrees from the vertical.
62

EXTRA ORAL RADIOGRAPHY
• Lateral oblique of the body of the mandible and maxilla.
• Lateral oblique of the body of the mandible and maxilla (modification)
of the projection.
• Lateral oblique of the ramus of the mandible.
• Lateral oblique of the ramus of the mandible(modification) of the
projection.
using wedge (10 degree),Using angle board.
63

Lateral oblique of the body of the mandible and maxilla.
• This projection shows the
dentition in the
premolar/molar region of
the maxilla and mandible,
the inferior cortex of the
mandible, and the angle and
ascending ramus of the
mandible.
64

• Direct the central ray at a
point 2cm below and behind
the angle of the contralateral
side of the mandible (see
figure).
65

Contd..
Positioning of the tube is dependent
upon the area of clinical interest, i.e.
• The choice of beam angulation varies
between 10 degrees upward and 10
degrees downward .
• The central ray is perpendicular to the
plane of the film.
66

Lateral oblique of the ramus of the mandible
Direction and centering of the X-
ray beam
• The central ray is directed posteriorly
with upward angulation (cephalad) of
10 degrees towards the center of the
ramus of the mandible on the side of
interest.
• The centering position of the tube is
the contralateral side of the mandible at
a point 2cm below the inferior border in
the region of the first/second permanent
molar.
67

Dental panoramic tomography
• Rotational panoramic radiography,
orthopantomography (OPT), dental
panoramic tomography (DPT),
panoral.
• Dental panoramic radiography is an
extra-oral radiographic technique
that produces an image of both jaws
and their respective dentitions on a
single film.
69

Indications
• Orthodontic assessment of the
presence/absence of teeth
• Detection and assessment of fractures
of the mandible;
•Assessment of large pathological
lesions (e.g. cysts, tumors,
osteodystrophy’s (A bone disorder that
adversely affects bone growth).
• Assessment of third molars before
surgical removal.
70

Principles of panoramic image formation
• Panoramic equipment is based upon a
simultaneous rotational movement of
the tube head and film
cassette/carriage in equal but opposite
directions around the patient’s head,
which remains stationary.
• The technique employs a slit-
collimated vertical X-ray beam, with
an eight-degree upward inclination, in
association with a similar collimation
slit in front of the film
cassette/carriage to receive the image.
71

References
•Clark’s 12th edit
•web
72

Thank you
for your kind
Attention
73

Questions
1.Which of these teeth have two roots?
a. Maxillary first premolars
b. mandibular molars
c. Bothe
d. None
2. In Fédération Dentaries International notation
P D
74
22 76

3.How much angulation is preferred for upper canine .
a. Caudally 30-35
b. Cranially 30-40
c. Cranially 45-50
d. Caudally 45-50
4. Exposure factor for dental radiography?
a.40-50 kVp / 10-15 mAs
b.50-60 kVp / 15-20 mAs
c.60-70 kVp / 5-10 mAs
d.60-80 kVp /7-10 mAs
75

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Technique of dental radiographic