This document provides information on dental anatomy, radiography techniques, and terminology used in dentistry. It describes the primary and permanent dentition, including tooth morphology and numbering systems. Intra-oral and extra-oral radiography techniques are outlined, along with film sizes and positioning principles. Key anatomical terms like mesial, distal, buccal, and lingual are defined.

1. Prepared by:
Behzad Ommani
Bachelor of Radiology
Master of Medical Engineering
Instructor Radiology Group
June, 2013

2. The primary or deciduous dentition comprises 20 teeth, with five in each quadrant of
the jaws.
These are replaced from six years onwards by a permanent dentition of 32 teeth. With
eruption of all 32 permanent teeth, there will be eight permanent teeth in each quadrant.
Some teeth may fail to develop or erupt, a complication most commonly affecting the
third permanent molars (the wisdom teeth).
From the midline moving posteriorly, the teeth in the anterior part of the jaws comprise
the central incisor, the lateral incisor and the canine (cuspid). This terminology is used
in both deciduous and permanent dentitions.
In the permanent dentition posterior to the canine, there are a first and a second
premolar (bicuspid) followed by a first, a second and, if they develop, a third
permanent molar. The deciduous dentition differs in that there are only two teeth
posterior to the deciduous canine, a first and a second deciduous molar
Introduction

3. Introduction

4. • The part of the tooth that projects above the gingiva (gum) and is evident in the
mouth is the crown; the portion embedded within the jaw is known as the root.
• The constriction between the crown and the root is known as the cervical region.
• The pulp chamber and canal, consisting of blood vessels and nerves supported by
loose connective tissue.
Introduction

5. • There are several internationally recognized methods of identifying the teeth that
require radiography :
• Palmer notation; and
• Fédération Dentaire International (FDI) notation.
In Iran Palmer notation is routine method.
 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.
Dental formulae

6. Introduction

7. Dental radiography involves techniques in which the film is placed either
inside the mouth (intra-oral radiography) or outside the mouth (extra-oral
radiography).
1)Intra-oral Radiography
2)Extra-oral Radiography
Type Technique

8. Intra-oral radiography :
The most frequently requested intra-oral projections are
bitewing radiography, periapical radiography and occlusal
radiography.
• Bitewing radiography is a lateral view of the posterior
regions of the jaws. The view demonstrates the crowns of
the teeth and the alveolar crestal bone of the premolar and
molar regions of both the maxilla and mandible.
• Periapical radiography is a lateral projection displaying
both the crown and the root of the tooth and the
surrounding bone.
• Occlusal radiography comprises a number of views in
which the film is positioned in the occlusal plane.
Type Technique

9. Extra-oral radiography
The most frequently requested extra-oral projections are dental
panoramic radiography, oblique lateral radiography and
cephalometry.
• Dental panoramic radiography is a projection that
produces an image of both jaws and their respective
dentitions on a single extra-oral film.
• Oblique lateral radiography demonstrates large areas of
the maxilla and mandible, with the region imaged
dependent on the technique chosen.
• Cephalometry employs techniques to produce standardized
and reproducible films of the facial bones for use in
orthodontic, orthognathic and implant treatment.
Type Technique

10. Dentists use the following terms to describe the tooth surfaces:
• 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.
.
Terminology

11. • Occlusal refers to the biting surface of both premolar and molar teeth.
• Incisal refers to the horizontal flat surface of the incisor teeth.
Terminology

12. • 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.
• It is necessary to adjust the position of the patient’s head before intra-oral radiography to
ensure that the appropriate occlusal plane is horizontal and the median plane is vertical.
• Common radiographic centring points are used to achieve these aims with the patient
seated and the head supported adequately.
Occlusal planes

13. • With the mouth open, the upper occlusal plane lies 4 cm below and parallel to a line
joining the tragus of the ear to the ala of the nose.
• The lower occlusal plane lies 2 cm below and parallel to a line joining the tragus of the ear
to the angle of the mouth with the mouth open
Occlusal planes

14. The following types of image receptors are used in dental radiography:
• Intra-oral radiography:
– direct or non-screen film;
– digital receptors.
• Extra-oral radiography:
– film-screen (usually rare-earth);
– digital receptors: storage phosphor and solid-state.
Image receptors

15. Several film sizes are available:
• Size 0 22 * 35 mm: used for small children and anterior
periapicals using the paralleling technique.
• Size 1 24 * 40 mm: used for bitewings in small children
and also for anterior projections in adults. Not available
routinely in the UK.
• Size 2 31 * 41 mm: 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 * 76 mm: used for occlusal projections of the
maxilla and mandible.
Intra-oral film sizes
Intra-oral double film packet

16. Many manufacturers are now producing digital imaging systems
specifically for dental radiography. The two methods of image
capture used are so
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.
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).
Digital receptors

17. In order to minimize distortion effects and to achieve optimal image geometry, the
following principles have been advocated for intra-oral radiography:
• The focal spot should be as small as possible.
• The focal spot-to-object distance should be as great as possible.
• The object-to-film distance (OFD) should be as small as possible.
• The film should be parallel to the plane of the object.
• The central ray should be perpendicular to both the object and the film.
Principles for optimal image geometry

18. 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.
Principles for optimal image geometry

19. 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.
Principles for optimal image geometry

20. Two methods are employed to stabilize the film intra-orally:
• The patient’s finger
• A film-holding instrument.
Stabilizer

21. Periapical Upper teeth

22. Periapical Lower teeth

24. • The paralleling technique requires that the
X-ray film is positioned parallel with the
long axes 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.
Periapical Paralleling technique

25. Three methods are available to position the film intra-orally:
• Bitewing tab: a heavy-duty paper tab attached to an intra-oral film. The
attachment can be either by an adhesive backing to the tab or by a bitewing loop
with an attached tab for the patient to bite on.
• Film-holding instrument: a simple device to localize the film, comprising a bite
block and a film-positioning slot.
• Film-holding beam-alignment instrument: a device with a bite block, rigid
backing and an extra-oral arm to correctly position the tube relative to the film
Bitewing radiography