Radiation: is energy that comes from a source and travels through space and may be able to penetrate various materials. It’s may occur in two forms : 1. particulate radiation , 2.electromagnetic radiation .

Dental radiograph: a photographic image produced on film by passage of x –ray through teeth & related structures.

Intraoral x-ray :

1.Periapical radiograph : which used to

examine apical area of the tooth and the

surrounding structure .

Indications for

Periapical radiograph:1.Detection of apical cyst 2.Evaluation of implants

2.Bitwing radiograph : it used to examine the

crown of both the maxillary & mandibular

teeth on one film.

Indications for

bitwing radiograph: 1. Evaluate inter proximal

carious teeth

2. Evaluate over hanged filling

3.Occlusal radiograph : that used to demonstrate an area of greater dimension than area appear in periapical radiograph,

With the longest

Dimension of the film in

A anterioposterio

Position.

Indications for

occlusal radiograph:

1. To evaluate fractures of

maxilla or mandible

2. To locate supernumerary teeth

Dental films:The media on which the

radiographic images of objects are

recorded, there is 2 types of films:

1.Self developing films :

2. Manual or wet processing films:

X_ray films :

X-ray film base composition :

Protective gelatin layer

Adhesive

Emulsion

( silver halide)

Film base

Cross sectional structure of double emulsion film

1) Film base; clear transparent sheet of

cellulose acetate with a bluish tint.

2) Adhesive; connects the emulsion to the

base.

3) Emulsion; on both sides of the base

where silver bromide(AgBr) crystals are

distributed in an the gelatin emulsion

4) Protective layer; protects the emulsion

from mechanical damage

1) Outer plastic wrapper; protects the film from light, saliva and mechanical damage, has two sides:

2) *Front; faces the x-ray tube, single color (white)

3) *Back; opposite side to x-ray tube, two colors (white and green). It has an opening tab to open the film during processibg

4) Black paper wrapper; protects the film base from light, saliva and damage during opening

1) Lead foil; thin sheet of lead present at the back of the film, has certain shapes on its surface, it:

2) *prevents x –rays from going to deeper tissues after passing through the film

3) *prevents scattered radiation from deeper tissues to come back to the film

4) Raised dot; an elevation embossed on each component of the film,has two surfaces

5) Convex; indicates front of the film (facing x-ray)

6) Concave; indicates back of film (facing lead foil)

Outer plastic cover

Front Back

Film

Lead

foil

Protective black paper