EXPOSURE AND TECHNIQUE ERRORS

DA 105

Dental Radiography

Questions What film exposure and technique

errors may be observed on dental radiographs?

What horizontal and vertical angulation errors may be observed on dental radiographs?

What is the proper film placement for bite-wing radiographs?

Dental Radiography

Exposure and Technique Errors Film exposure errors Technique errors (periapical films) Technique errors (bite-wing films) Miscellaneous technique errors

Exposure and Technique Errors

Purpose To describe film exposure problems

and periapical, bite-wing, and miscellaneous technique errors

Film Exposure Errors

Exposure Problems Unexposed film Film exposed to light

Time and Exposure Factor Problems Overexposed film Underexposed film

Unexposed Film Appearance

The film appears clear Cause

Failure to turn on the x-ray machine Electrical failure Malfunction of the x-ray machine

Correction Make certain the x-ray machine is turned on

and listen for the audible exposure signal

 An unexposed film appears

clear

Film Exposed to Light Appearance

The film appears black Cause

The film was exposed to white light Correction

Do not unwrap in a room with white light

Check the darkroom for light leaks Turn off all lights in the darkroom

except the safelight

A film exposed to light appears

black

Overexposed Film

Appearance Film appears dark

Cause Excessive exposure time, kilovoltage,

milliamperage Correction

Check settings and reduce as needed before exposing film

An overexposed film appears

dark

Underexposed Film

Appearance The film appears light

Cause The film was underexposed

Correction Check the exposure time, kilovoltage,

and milliamperage settings on the x-ray machine before exposing the film

 An underexposed film appears light

Technique Errors (Periapical Films)

Film Placement Problems Correct film placement Incorrect film placement

Absence of apical structures Dropped film corner

Angulation Problems Incorrect horizontal angulation Incorrect vertical angulation

PID Alignment Problems Cone-cut with Film Holder Cone-cut without Film Holder

Correct Film Placement

Each periapical film must be positioned in a certain way to show specific teeth and related anatomic structures The edge of the periapical film must

be placed parallel to the incisal or occlusal surfaces of the teeth and extend 1/8th inch beyond the incisal or occlusal surfaces

Correct periapical film placement demonstrates the entire tooth, including

the apex and surrounding structures

Absence of Apical Structures

Haring (p. 276) (Fig. 20-6) Appearance

No apices appear on the film Cause

The film was not positioned in the patient’s mouth to cover the apical regions of the teeth

Correction Make certain no more than 1/8th inch of the

film edge extends beyond the incisal-occlusal surfaces of the teeth

Improper film placement; no apices appear on this film

Dropped Film Corner Appearance

The occlusal plane appears tipped or tilted Cause

The edge of the film was not placed parallel to the incisal-occlusal surfaces of the teeth

Correction Make certain the edge of the film is placed

parallel to the incisal-occlusal surfaces of the teeth

  Improper film placement; a dropped film corner is seen when the edge of the film is not placed parallel to the incisal or occlusal surfaces of the

teeth

Incorrect Horizontal Angulation

Appearance Overlapped contacts

Cause The central ray was not directed

through interproximal spaces Correction

Direct the x-ray beam through interproximal regions

Incorrect horizontal angulation results in overlapped contact

areas

Incorrect Vertical Angulation

Foreshortened images Appearance

Short teeth with blunted roots Cause

Excessive vertical angulation Correction

Do not use excessive vertical angulation with the bisecting technique

If the vertical angulation is too steep, the image of the tooth on the film is shorter

than the actual tooth; the images are

foreshortened

Incorrect Vertical Angulation

Elongated images Appearance

Long, distorted teeth Cause

The vertical angulation was insufficient Correction

Use adequate vertical angulation with the bisecting technique

If the vertical angulation is too flat, the image of the tooth on the film is longer than the actual

tooth; the images are elongated

PID Alignment Problems

Cone-cut with film holder Appearance

A clear area appears on the film Cause

The PID was not properly aligned with the periapical film holder

Correction Make certain the x-ray beam is centered

over the film

A cone-cut is seen when the PID is not properly aligned with the periapical film-holding device

PID Alignment Problems

Cone-cut without film holder Appearance

A clear area appears on the film Cause

The PID was not directed at the center of the film

Correction Make certain the x-ray beam is centered

over the film

 A cone-cut appears as a curved unexposed (clear) area on a

radiograph

Technique Errors (Bite-Wing Films) Film Placement Problems

Correct film placement Incorrect film placement

Angulation Problems Incorrect horizontal angulation Incorrect vertical angulation

PID Alignment Problems Cone-cut with film holder Cone-cut without film holder

Correct Film Placement

Premolar bite-wing The resulting film shows both the

maxillary and mandibular premolars and distal contact areas of both canines

Molar bite-wing The resulting film shows both the

maxillary and mandibular molars

Correct film placement for the

premolar bite-wing

Correct film placement for the molar bite-wing

Incorrect Film Placement Premolar bite-wing

Appearance Distal surfaces of the canines are not visible on

the film Cause

The bite-wing film was positioned too far posteriorly in the mouth

Correction Make certain the anterior edge of the bite-wing

film is positioned at the midline of the mandibular canine

  Incorrect film placement for

the premolar bite-wing

Incorrect Film Placement Molar bite-wing

Appearance Third molar regions are not visible on film

Cause The bite-wing film was positioned too far

anteriorly in the mouth Correction

Make certain the anterior edge of the bite-wing film is positioned at the midline of the mandibular second premolar

 Incorrect film placement for the

molar bite-wing

Incorrect Horizontal Angulation

Appearance Overlapped contacts on the film

Cause The central ray was not directed

through the interproximal spaces Correction

Direct the x-ray beam through the interproximal spaces

Overlapped interproximal contacts result from incorrect horizontal

angulation

Incorrect Vertical Angulation

Appearance Images appear distorted on the film

Cause The vertical angulation was incorrect

Correction Always use a +10-degree vertical

angulation with the bite-wing technique

 Incorrect vertical angulation causes the images to appear

distorted

Cone-Cut With Film Holder

Appearance A clear area appears on the film

Cause The PID was not properly aligned with

the film holder Correction

Make certain the PID and the aiming ring are aligned

A, A cone-cut is seen when the PID is not properly aligned with the bite-wing film-holding device. B, A cone-cut can also be produced with rectangular collimation; the PID is

not properly aligned with the bite-wing film-holding device

Cone-Cut Without Film Holder

Appearance A clear area appears on the film

Cause The PID was not directed at the

center of the film Correction

Make certain the x-ray beam is centered over the film

A cone-cut appears as a curved unexposed (clear)

area on a radiograph

Miscellaneous Technique Errors

Film Bending Film Creasing Phalangioma Double Exposure Movement Reversed Film

Film Bending

Appearance Images appear stretched and distorted

Cause The film was bent excessively

Correction Check film placement before exposure

A bent film appears distorted

Film Creasing

Appearance A thin radiolucent line appears on the film

Cause The film was creased

Correction Do not bend or crease the film

excessively

A film crease appears as a thin radiolucent line

Phalangioma Haring (p. 282) (Fig. 20-23)

Appearance The patient’s finger appears on the film

Cause The patient’s finger was positioned in front

of the film Correction

Make certain the patient’s finger is placed behind the film

This film demonstrates a phalangioma; the bones of a

patients finger appear on the film

Double Exposure

Appearance A double image appears on the film

Cause The film was exposed twice in the

patient’s mouth Correction

Always separate exposed and unexposed films

This film demonstrates a double exposure

Movement Appearance Blurred images appear on the film

Cause The patient moved during exposure of

the film Correction

Instruct the patient to remain still while the film is being exposed

Movement results in a blurred image

Reversed Film Appearance

Light images with a herringbone pattern appear on the film

Cause The film was placed backward in the mouth

and then exposed Correction

Always place the white side of the film adjacent to the teeth

A reversed film appears light with a herringbone (or tire-track) pattern. The tire-track pattern is seen on the lead-foil

backing within the film packet

EXPOSURE AND TECHNIQUE ERRORSDIAGNOSTIC DENTAL RADIOGRAPH:

1.FILM EXPOSURE ERRORS:

EXPOSURE PROBLEMS

a) Unexposed film

APPEARANCE CAUSE CORRECTION

b) Film exposed to light

TIME AND EXPOSURE

FACTOR PROBLEMS

a) Overexposed

film

b) Underexposed film

TECHNIQUE ERRORS(PERIAPICAL FILMS)

1. FILM PLACEMENT PROBLEMS2. ANGULATION PROBLEMS3. PID ALIGNMENT PROBLEMS

FILM PLACEMENT PROBLEMS

ERROR APPEARANCE CAUSE CORRECTION

CORRECT FILM

PLACEMENTINCORRECT FILM

PLACEMENTa) ABSENCE OF

APICAL STRUCTURES

b) DROPPED FILM CORNER

ANGULATION PROBLEMS

ERROR APPEARANCE CAUSE CORRECTION

INCORRECT HORIZONTAL ANGULATION

INCORRECT VERTICAL

ANGULATIONa)

FORESHORTENED IMAGE

b) ELONGATED IMAGE

PID ALIGNMENT PROBLEMS

ERROR APPEARANCE CAUSE CORRECTION

CONE-CUT WITH FILM

HOLDER

CONE-CUT WITHOUT

FILM HOLDER

TECHNIQUE ERRORS(BITE-WING FILMS)

1. FILM PLACEMENT PROBLEMS2. ANGULATION PROBLEMS3. PID ALIGNMENT PROBLEMS

FILM PLACEMENT PROBLEMS

ERROR

CORRECT FILM PLACEMENT1)PREMOLAR BITE-WING

2)MOLAR BITE-WING

INCORRECT FILM PLACEMENT1)PREMOLAR BITE-WING

2)MOLAR BITE-WING

ANGULATION PROBLEMS

ERROR APPEARANCE CAUSE CORRECTION

INCORRECT HORIZONTAL ANGULATION

INCORRECT VERTICAL

ANGULATION

PID ALIGNMENT PROBLEMS

ERROR APPEARANCE CAUSE CORRECTION

CONE-CUT WITH FILM

HOLDER

CONE-CUT WITHOUT

FILM HOLDER

MISCELLANEOUS TECHNIQUE ERRORS

ERROR APPEARANCE CAUSE CORRECTION

1.FILM BENDING

2.FILM CREASING

3.PHALANGIOMA

4.DOUBLE EXPOSURE

5.MOVEMENT

6.REVERSED FILM