Al-Azhar University of Gaza

Faculty of Dentistry

DR/ ASHRAF SHAMIA

DR/ NOOR M. ABU AMARA

Sep. 2015

ORAL RADIOLOGY

Introduction To Oral Radiology

1- Radiology

2- Roentgenology

3- Dental radiology

4- Dental radiography

5- Radiograph

6- Radiation

7- Radiolucent

8- Radiopaque

Terminology

Radiology

Science that deals with application of high- energy radiation in diagnosis, therapeutic and researches.

Roentgenology

Science that deals with application of X-ray on any field.

Dental radiology

It is the branch of science that deals with the use of radiation in diagnosis of dental diseases.

Dental radiography

It is the art of producing an image or picture for intra- or extra-oral structures on a dental film using X-ray.

Radiograph

It is the shadow features (image) received on a radiation-sensitive film emulsion by exposure to ionizing radiation directed through an area or region or substance of interest, followed by chemical processing of the film. It is basically dependent on the differential absorption of radiation directed through heterogeneous media.

Radiation

It is the process of emission, propagation and transmission of energy by atoms in the form of waves.

Radiolucent

Objects that permitting the passage of radiant energy with relatively little attenuation by absorption and appear black on the film, such as silicate restoration, pulp tissues, gingiva, and carious lesion.

Another definition; Objects partly or wholly penetrable by roentgen rays; the image of such a material on the film ranges from dark gray to black.

Radiopaque Objects that absorb X-rays and appear white on radiograph, such as amalgam restoration, enamel, and bone.

Another def. : Objects that not freely penetrable by radiation.

OR Objects highly resistant to penetration by roentgen rays; the image of such a material appears on the film within range of gray to white.

The purpose of dental radiography is to record images of a patient's oral structures on film by using X-rays. When the X-ray films are processed, the resulting radiographs provide the dental officer with a valuable diagnostic aid.

In the case of death, radiographs can be used to aid in identification "Forensic Dentistry."

Purposes of Dental Radiology

Radiographic examination provides important anatomical information to determine the different pathologies and conditions of the teeth's and tissues like bone supports:

Defects and Variations in Tooth Density Trauma and Exodontia Fractures Endodontic Treatment of Teeth Developmental Defects and Anomalies Swellings, Cysts and Neoplasm Metabolic Diseases Orthodontic treatment

Presence and severity of periodontal diseases, abscesses or infections

Shape and sizes of the roots

Maxillary sinus disease

The exact locations of impacted teeth, position of third molars and the status of develop

Cavities that can not be seen directly or in early stage, allowing patients to receive preventive treatment.

FRACTURE

PERIAPICAL RADIOLUCENCY

ENDODONTICS

DENTINOGENESIS IMPERFECTA

DENTIGEROUS CYST

MALOCCLUSION

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Clinical Examination

Radiographs

Diagnosis

Treatment

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Are a form of pure energy units belonging to

electromagnetic spectrum characterized by having a

very short wave length and have the ability of producing

images of the body tissues.

They are invisible, penetrative and travel with the same

speed as visible light. They are usually produced by

bombarding a target of high atomic number with fast

electrons in a high vacuum

X-Rays

How are X-rays created?

When fast-moving electrons collide with matter, X-radiation is produced.

The most efficient means of generating X-rays is an X-ray tube.

In it, X-rays are produced by directing a high- speed stream of electrons against a metal target. As they strike the atoms of the target, the electrons are stopped. Most of their energy is transformed into heat, but a small proportion is transformed into X-rays.

X-ray machine consists of :

1. Tubehead : produces the x-rays

Tube: Cathode + Anode

Accessories: Filters + collimators + cones

2. Control panel: which allows you to alter the duration of the x-ray beam (exposure time) and, on some x-ray machines, the intensity (energy) of the x-ray beam.

3. Support arms: which allow you to move the tubehead

around the patient’s head .

PID = position indicating device

BID = beam indicating device

PID, BID (cone)

X-ray Tubehead

degrees

Control panel

Timer :

A/ Automatic timers

1- Direct or immediate timers: It attached to a long cord to enable the operator to go away from the field of radiation. Operator press on a button just to activate the exposure while the time is pre adjusted and the exposure will stop automatically even if the operator continuous to press the button.

2- Delayed timers: This type provide about 9 second before the start of exposure.

B/ Manual timers

Direct type in old x-ray machines. The exposure is controlled manually (like the clock alarm) and exposure will stop only if the operator stop pressing on the button.

Intraoral Radiographic Techniques:

films located inside the mouth

Extra-oral Radiographic Techniques:

films located outside the mouth

Classification of Dental Radiographic

Techniques

Intra-oral Radiographic Techniques

A- Periapical B- Bite-wing C- Occlusal

Paralleling

technique

Bisecting angle

technique

USES

Extent of alveolar bone loss

Periapical film (Parallel method)

The whole length of teeth, Periapical area

Periapical film (Bisection method)

Interproximal Caries

Alveolar bone involvement

Bitewing film

A section of maxilla or mandible Occlusal film

Highlights the entire tooth.

Shows tooth apices and surrounding structures in a particular

intra oral area.

Detects changes in the bone surrounding the roots of the tooth.

Used to study crown & root length and tooth morphology.

To evaluate root apex formation.

Periapical Radiography

PERIAPICAL RADIOGRAPHIC TECHNIQUES

1- BISECTING ANGLE TECNIQUE

PERIAPICAL RADIOGRAPHIC TECHNIQUES

2- The paralleling technique (long cone tech.) or

Right angle technique

Reveals the crown, neck and coronal third roots of both upper

and lower posterior teeth and dental arches.

Detects inter-proximal lesions.

Useful for determining the proper fit of a crown/cast

restoration and marginal integrity of fillings.

Bitewing Radiography

Shows relationship of the teeth to underlying structures in the

alveolar process (such as cysts, abscesses)

Nearly the full upper or lower arch is shown.

To determine bucco-lingual position of impacted teeth

To examine cleft palate.

Occlusal Radiography

They allow the Dentist to view large areas of the jaws and skull

on a single radiograph not covered by intraoral films.

Purpose and uses:

Examine large areas of the jaws and Skull.

Study growth and development of bone and teeth.

Detect fractures and evaluate trauma

Detect pathological lesions and Diseases of the jaws.

Detect and evaluate impacted teeth.

Evaluate TMJ Disorders.

Extra-oral Radiographic Techniques

Except for the panoramic radiographs, extra-oral radiographs are

not frequently used by General practitioners, Major users are

orthodontists, prosthodontists, oral surgeons.

Orthodontists: uses lateral cephalometric radiograph to:

Measure and compare changes in Growth and development of

bone and the teeth through pre & progress and post treatment

records.

Prosthodontists: Use Facial profile radiographs (lateral

cephalometric ) to record :

The contour of the lips and the face

The relationship of the teeth before removal, this will help

them construct prosthetic appliances that look natural.

Oral surgeons: use Extra-oral radiographs extensively to:

Evaluate trauma.

Determine the location and extent of fractures.

Locate impacted teeth & abnormalities .

Malignancies .

Injuries to TMJ

Extra-oral Radiographic Techniques:

• Panoramic radiograph

• Skull views

PA Skull PA Cephalogram

AP Skull Towne’s view

Submento-vertex view (base of the skull)

Lateral skull Lateral cephalogram

• Maxillary sinus

PA Water’s view

Modifications - Grenger’s view

Caldwell’s projection

• Mandible

PA Mandible

Lateral oblique views

Body

Ramus

• TMJ views

Transcranial

Transpharyngeal

Transorbital

Reverse Towne’s view

Panoramic Radiography (OPG)

Panorex

Shows a 2-dimensional view of a half circle from ear to ear.

Purpose:

Evaluation of trauma and 3rd molars.

Evaluation of teeth development & developmental anomalies.

Evaluation of cysts , tumors.

Temporomandibular Joint Dysfunction and ankylosis.

Examination of maxillary sinuses.

• It shows the entire skull from the side and the X-ray passes

from the lateral side

Purpose:

• Orthodontic purpose

1.Pre and post treatment records.

2.Evaluate the growth and development

3.Facial soft tissue profile of the face

• Surgeons also use it for pre and post treatment records

• Trauma

• Pathology

• Developmental Abnormalities

( Lateral skull )

Cephalometric Radiography

Purpose:

To Evaluate the maxillary , frontal and ethmoid sinuses.

Water’s view Radiography

Purpose:

To examine fractures of the condylar neck of the mandible.

Reverse – towne Radiography

Purpose:

• Used to show the base of the skull.

• The position and orientation of the condyles.

• Sphenoid sinus and fractures of the Zygomatic arch.

Submento-vertex Radiography

• Tomograms

• Sialography

• Computed tomography

• MRI

• Ultrasonography (USG)

• Cone beam CT

Advanced Radiographic Techniques

Show a particular layer or "slice" of the mouth while blurring

out all other layers. This type of X-ray is useful for examining

structures that are difficult to clearly see … for instance,

because other structures are in very close proximity to the

structure to be viewed .

Tomograms

Involves visualization of the salivary glands following the

injection of a dye. The dye, called a radiopaque contrast

agent, is injected into the salivary glands so that the organ can

be seen on the X-ray film (the organ is a soft tissue that would

not otherwise be seen with an X-ray). Dentists might order this

type of test to look for salivary gland problems, such as

blockages or Sjogren's syndrome.

Sialography

Otherwise known as CT scanning, shows the body's interior

structures as a three-dimensional image. This type of X-ray is

performed in a hospital rather than a dentist's office.

Indications:

The diagnosis and extent of -

Variety of infections

Osteomyelitis

Cysts

Benign and malignant tumors

Trauma in the maxillofacial region

Lesions involving the bone

3D CT has been applied to trauma and craniofacial reconstructive surgery and used

for treatment of congenital and acquired deformities

Computed tomography

Indications:

To evaluate the position and integrity of the disk in the TMJ.

Neoplasia involving the soft tissues, such as tongue, cheek, salivary glands,

and neck.

Determining malignant involvement of lymphnodes.

Determining peri-neural invasion by malignant neoplasms.

With contrast, enhances the image resolution of neoplasia.

MRI

Indications:

For the evaluation of

Neoplasms in the thyroid, parathyroid or salivary glands or

lymph-nodes.

Stones in salivary glands or ducts

Vessels of neck

To guide fine-needle aspiration in the neck

Ultrasonography (USG)

A recent technology initially

developed for angiography in

1982 and subsequently applied to

maxillofacial imaging.

It constitutes of:

1. Two-dimensional digital array

providing an area detector fixed

on a rotating gantry

2. A three-dimensional (3D) cone

shaped x-ray beam

CONE-BEAM Computed

Tomography

PRINCIPLE :

Cone-beam scanners use a two-dimensional digital array

providing an area detector rather than a linear detector as CT

does.

This is combined with a three-dimensional (3D) x-ray beam

with circular collimation so that the resultant beam is in the

shape of a cone, hence the name "cone beam."

APPLICATIONS :

Orthodontic treatment planning

Dental implants

Temporomandibular joints for osseous degenerative changes

Evaluation of wisdom teeth vs. mandibular nerve

Endodontic assessment

Assessment of impacted teeth, fractured teeth and jaws,

periapical infections and periodontal diseases.

Benign calcifications ( tonsilloliths, lymph-nodes, salivary

gland stones) can also be identified.

C B C T - ORTHO ,,,, Cephalo Tracing

C B C T ,,, Nerve Mapping

CBCT- TMJ view

ADVANTAGES:

Lower dose than helical

Compact design

Superior images to Panoramic

Low cost

Low heat load

High speed scanning (less than 30 secs)

DISADVANTAGES:

Worse low contrast detectability

Poor soft tissue contrast

Long scan times = motion artifacts

Slightly Inferior quality to conventional CT

Image noise

Metal artifacts

Dental radiographs produced with a special computer create

digital images (computerized dental radiographs) that can be

displayed and enhanced on the computer monitor.

It involves the use of a radiography machine like that used for

conventional x-rays. But instead of using films, the clinician

makes digital images using a small electronic sensor or an

image receptor placed in mouth to capture the image.

Digital Radiography

•DOSE REDUCTION

• IMAGE MANIPULATION

• TIME

• STORAGE

• TELERADIOLOGY

• ENVIRONMENTALLY FRIENDLY

ADVANTAGES

•COST

•CROSS-INFECTION CONTROL DISADVANTAGES