exposure and technique errors

Question 1

appearance, cause and correction for unexposed film

Answer 1

• appearance: the film appears clear
• cause: failure to turn on the x-ray machine, electrical failure or malfunction of the x-ray machine
• correction: make certain the x-ray machine is turned on and listen for the audible exposure signal

Question 2

appearance, cause and correction for film exposed to light

Answer 2

• 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 leaks, and turn off all lights in the darkroom except safelight

Question 3

appearance, cause and correction for overexposed film

Answer 3

• appearance: film appears dark
• cause: excessive exposure time, kilovoltage, milliamperage
• correction: check settings and reduce as needed before exposing film

Question 4

appearance, cause and correction for underexposed film

Answer 4

• appearance: the film appears light
• cause: the film was underexposed (results from inadequate exposure time, kilovoltage or milliamperage)
• correction: check the exposure time, kilovoltage, and milliamperage settings on the x-ray machine before exposing the film

Question 5

technique errors for periapical films

Answer 5

• film placement problems
• angulation problems
• PID alignment problems

Question 6

technique errors for periapical films: film placement problems

Answer 6

• correct film placement

- incorrect film placement: absence of optical structures, dropped film corner

Question 7

technique errors for periapical films: angulation problems

Answer 7

• incorrect horizontal angulation

- incorrect vertical angulation

Question 8

technique errors for periapical films: PID alignment problems

Answer 8

• cone-cut with film holder

- cone-cut without film holder

Question 9

correct film placement

Answer 9

• 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 incisor or occlusal surfaces of the teeth and extend 1/8th of an inch beyond the incisal or occlusal surfaces

Question 10

appearance, cause and corrections for absence of apical structures

Answer 10

• 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 of an inch of the film edge extends beyond the incisal-occlusal surfaces of the film

Question 11

appearance, cause and corrections of dropped film corner

Answer 11

• 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

Question 12

appearance, cause and correction for incorrect horizontal angulation

Answer 12

• appearance: overlapped contacts
• cause: the central ray was not directed through interproximal spaces
• correction: direct the x-ray beam through interproximal regions

Question 13

appearance, cause and correction for incorrect vertical angulation: foreshortened images

Answer 13

• appearance: short teeth with blunted roots
• cause: excessive vertical angulation
• correction: do not use excessive vertical angulation with the bisecting technique

Question 14

appearance, cause and correction for incorrect vertical angulation: elongated images

Answer 14

• appearance: long, distorted teeth
• cause: the vertical angulation was insufficient
• correction: use adequate vertical angulation with the bisecting technique

Question 15

appearance, cause and correction for PID alignment problems: cone cut with film holder

Answer 15

• 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 entered over the film

Question 16

appearance, cause and correction for PID alignment problems: cone cut without film holder

Answer 16

• appearance: a clear area appears on the film
• cause: the PID was not directed at the centre of the film
• correction: make certain the x-ray is entered over the film

Question 17

technique errors for bite-wing films:

Answer 17

• film placement problems: correct and incorrect film placement
• angulation problems: incorrect horizontal angulation, incorrect vertical angulation
• PID alignment problems: cone-cut with film holder, cone cut without film holder

Question 18

correct film placement for premolar bite-wings

Answer 18

• the resulting film shows both the maxillary and mandibular premolars and distal contact areas of both canines

Question 19

correct film placement for molar bite-wings

Answer 19

• the resulting film shows both the maxillary and mandibular molars

Question 20

appearance, cause and correction for incorrect film placement for premolar bite-wings

Answer 20

• 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

Question 21

appearance, cause and correction for incorrect film placement for molar bite-wings

Answer 21

• 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

Question 22

appearance, cause and correction for incorrect horizontal angulation in bite-wings

Answer 22

• 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

Question 23

appearance, cause and correction for incorrect vertical angulation is bite-wings

Answer 23

• 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

Question 24

appearance, cause and correction for cone-cut with film holder in bite-wings

Answer 24

• 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

Question 25

appearance, cause and correction for cone-cut without film holder in bite-wings

Answer 25

- appearance: a clear area appears on the film - cause: the PID was not directed at the centre of the film - correction: make certain the x-ray beam is entered over the film

Question 26

miscellaneous technique errors:

Answer 26

- film bending - film creasing - phalangioma - double exposure - movement - reversed film

Question 27

appearance, cause, and correction for film bending

Answer 27

- appearance: images appear stretched, and distorted - cause: the film was bent excessively - correction: check film placement before exposure

Question 28

appearance, cause and correction for film creasing

Answer 28

- appearance: a thin, radiolucent line appears on the film - cause: the film was creased - correction: do not bend or crease the film excessively

Question 29

appearance, cause and correction or phalangioma

Answer 29

- appearance: the patient's finer appears on the film - cause: the patient's finger was positioned in front of the film - correction: use film holder

Question 30

appearance, cause and correction for double exposure

Answer 30

- 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

Question 31

appearance, cause and correction for movement

Answer 31

- 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

Question 32

appearance, cause and correction for reversed film

Answer 32

- 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