Errors of dental radiography

Prepared by :WRia S. Rasheed

I. Technique & Projection errors.

II.Exposure errors.

III.Processing errors.

contents:

Films with errors should be avoided due to the following reasons:Retake will lead to:

•Expose the patient to unnecessary radiation.•Waste film & time (money).•Interfere with accurate interpretation and diagnosis.

Causes of faulty radiograph

The majority of the errors produced can be categorized into three groups:

I. Technique & Projection errors.

II.Exposure errors.III.Processing errors.

I. Technique & Projection errors:

a. Patient preparation error:

b. Film placment artifact:

•Blurred image

•Radiopaque artifact

•Reversed film •Double image•Apices cut off •Dot artifact•Dropped film corner

•Crown not shown

•Black line •Area of interest not shown•Distortion

c. Projection errors:Incorrect vertical angulation.•Incorrect horizontal angulation•PID alignment artifact•Incorrect vertical angulation

Technique & Projection errorsa. Patient preparation error

Radiopaque artifactDental appliances, body piercings, jewelry & eye glasses left in the mouth during exposure will appear as radiopaque artifact superimposed over the dental image. Correction: all this items should be removed before placing of the film.

Technique & Projection errorsa. Patient preparation errorBlurred image

Movement of the film, patient or X-ray tube head during exposure will result in a blurred image.Correction: the operator should explain for the patient & remind him to remain motionless during exposure.

Technique & Projection errorsb. Film placment artifact

Double imageWhen an exposed film is re-exposed the resulting film will have 2 superimposed images

Technique & Projection errorsb. Film placment artifactReversed film

Low density with herring bone, tire-track or dotted pattern, as a result of directing the X-ray through the lead foil side of the film back.

Technique & Projection errors

b. Film placement artifactDot artifactThe identification dot produce a circular radiolucent artifact on the final radiograph. This may interfere with interpretation of the apical areas of the teeth.

Technique & Projection errorsb. Film placment artifactApices cut off

Occur when the film is not positioned apically enough to record the entire tooth.

Crown not shown

Technique & Projection errorsb. Film placment artifact

There is no enough film extending occlusally.

Technique & Projection errorsb. Film placment artifact

Dropped film cornerThe film edge is not placed parallel to the occlusal surface of the teeth.

Technique & Projection errorsb. Film placment artifact

Area of interest not shownThis is the result of not placing the film to cover all the teeth in the area of interest and not centralizing the film over the area of interest.

Technique & Projection errorsb. Film placment artifactBlack lineDue to excessive bending of the film prior to its placement inside the patient’s mouth (pressure causes ionization of silver halide upon processing will be darker).

Technique & Projection errorsb. Film placment artifactDistortion

Due to bending of the film to eliminate the patient’s discomfort specially in lower premolar area and upper central incisors.

normal distorti

on

Technique & Projection errors c. Projection errors

Incorrect vertical angulationIt will lead to:•Elongated image due to insufficient v. angulation ( too flat), or•Shortened image due to excessive v. angulation ( too steep)

Technique & Projection errorsc. Projection errors

Technique & Projection errorsc. Projection errors

Technique & Projection errorsc. Projection errors

Incorrect horizontal angulation (overlap)

Is the appearance of the interproximal surfaces of the adjacent teeth over each other. This is due to improper H.A.

Technique & Projection errorsc. Projection errors

Technique & Projection errorsc. Projection errors

PID alignment artifactIf the PID is misaligned and the x-ray is not centered over the film, a partial image is seen on the resultant radiograph, this partial image is called cone-cut.It appear as a clear area with curved outline.

II. Exposure errors.

• Blank image.• Low density image.• High density image.• Image with high and low contrast.

Exposure errorsBlank image

A film that didn’t receive radiation will have no image and will appear clear.

Errors in machine operation: Excessive milliamperage Excessive kilovoltage Excessive time Film_ source distance too short processing errors: Accidental exposure to light Inadequate fixation High developer temp. High developer conc. High developing time

High density image

Low density (faint) image (too light)

Exposure errors

Causes:• Old developer solution• Low developer temp.• Low developing time• Low developer conc.• Incomplete fixation

III. Processing errorsChemical errors:•Light image.•Dark image.•Blank image.•Reticulation.•Black spot or patch.•White spot or patch.•Yellowish brown discoloration.

Film Handling errors:•Writing lines•Developer cut off•Fixer cut off•Finger nail artifact•Smudge.•Scratched film•Static electricity

Processing errorsChemical errors

ReticulationWhen the film subjected to a sudden temperature changes between the developer and water.Appear as cracked film.

Processing errorsChemical errors

Black spot or patchDeveloper contamination before immersion into the developer solution.

White spot or patch

Processing errorsChemical errors

Contamination with fixer before processing

Yellowish brown discoloration

Processing errorsChemical errors

Exhausted solution or insufficient rinsing

Processing errorsFilm Handling errors

Writing linesAppear on the radiograph due to writing on the film packet with ballpoint pen or lead pencil.It may appear black or white.

Finger nail artifactBlack or whit crescent shape mark due to rough handling of the film.

Developer cut off

Processing errorsFilm Handling errors

A straight white border . The film may not be completely immersed in the developer solution.

Fixer cut off

Processing errorsFilm Handling errors

A straight black border. The film may not be completely immersed in the fixer solution.

Processing errorsFilm Handling errors

Smudge (finger print)When the film touched by fingers contaminated with developer or fixer

Processing errorsFilm Handling errors

Scratched film

White lines appear on the film due to careless handling of the film.

Processing errorsFilm Handling errors

Static electricityThin black branching lines Occurs when two surfaces are rubbed together against each other vigorously, this creates an electric charges with visible light emitted which is capable of exposing the x-ray film, thus leading to ionization of AgBr crystals at this area.Occur most frequently during periods of low humidity

Metallic partial denture

Blurred

Reverse image

Apices cut off

Dropped corner

Distortion

Elongation

Horizontal overlap

Double image

Low denisty

Static electricity

White spot or patch

Yellowish brown discoloration

Reverse image

Cone-cutDeveloper cut off