Xray - Week 4 PP

Question 1

Bisecting Technique

Answer 1

another method that can be used to expose periapical films - when you cant use a xcp kit to take an xray

• The major disadvantage of this technique is that the image is dimensionally distorted
• This technique should be used only as an
  alternative method in special circumstances,
  when it is not possible to use the paralleling
  technique
• not recommended, not used at Sait - “alternative method”

Question 2

Bisecting Steps

Answer 2

Step 1 - position the sensor occlusal plane parallel to the floor and the mid-sagittal plane perpendicular to the floor

Step 2: place the film against the lingual
(backside) of the tooth.

Step 3: Visualize an imaginary line that bisects (divides in half) the angle formed by the film and the tooth

Step 4: Center the PID over the film and position the opening of the PID parallel to this imaginary line. This will direct the central ray of the x-ray beam perpendicular to the imaginary line

Question 3

Film holders - for bisecting

Answer 3

EeZee-Grip holder - for digital sensor
Stable Disposable Holder
Rinn BAI Bite-block

Question 4

Why do dentist requisition bitewings?

Answer 4

To look for decay between the teeth

Interproximal radiographs are commonly used to assess and/or confirm general defects in teeth and/or surrounding tissues.
They are commonly requisitioned during
Recall/Check up Appointments.

Question 5

BW Radiographs - purpose

Answer 5

Detects interproximal decay
* Detect loss of alveolar bone
* Changes in the pulp
* Overhanging restorations
* Poor Margins on Crowns
* Recurrent decay beneath restorations

Question 6

Bitewing Film Placement

Answer 6

Bitewings can be taken both vertically and horizontally

Question 7

Bitewing exposure

Answer 7

Bitewings can be taken using a beam alignment device (XCP) or by using a bitewing tab

when exposing a bitewing, the angulation of the PID is critical

Both Vertical Angulation (up-and-down) and
Horizontal Angulation (side-to-side) must be
correct to expose a proper bitewing

Question 8

Vertical Angulation

Answer 8

The vertical angulation of the PID must be at +10 degrees

Question 9

Horizontal angulation

Answer 9

To maintain the correct horizontal angulation the central ray must be directed perpendicular to the curvature of the arch, through the contact areas of the teeth

Question 10

Bitewing sequence

Answer 10

Typically on adults 4 bitewings are taken.
1 pre-molar and 1molar bitewing on each side

Question 11

Pre-molar bitewing

Answer 11

Must include edges of canines, premolars visible, with open contacts

Question 12

Molar bitewing

Answer 12

Must include entire lower second molar, open molar contacts, no cone-cuts

Question 13

Bitewing film sizing

Answer 13

Size 0 - primary dentition - posterior teeth - one on each side

Size 1 - mixed dentition - posterior teeth - one on each side

Size 2 - permanent dentition - premolar teeth, molar teeth - two on each side

Question 14

Molar Bitewing

Answer 14

Must include distal third molar/wisdom teeth - can be tricky to capture

Question 15

What is a cone cut?

Answer 15

Is when we line up the PID in such a way that we haven’t captured the whole sensor.

It creates an xray with sections missing

Question 16

Tips to avoid cone cuts during bitewing exposure / tips for successful bitewing exposure

Answer 16

Ensure sensor is lined up properly inside ring of XCP positioning device BEFORE exposure
* Ensure PID is steady and ask patient to not move once it is placed
* When not using a positioning device ensure entire film is covered by PID
Position patients head Parallel to the floor
* Ensure that the film or sensor is placed in the correct position for the bitewing being
exposed
* Stand directly behind the tube-head and look along the side of the PID, no portion of the receptor should be visible

Question 17

Pre-molar bitewing positioning tips

Answer 17

Make sure the receptor is covering the distal surface of the canines

Question 18

Molar bitewing

Answer 18

make sure the receptor covers the distal of the second molar (or third molar if they have)

Question 19

Patient preparation for xrays

Answer 19

1. Explain the radiographic procedure(s) to the patient.
2. Select the settings on the control panel
3. Adjust patient chair so that the patient sits upright
4. Adjust headrest to support and position patient’s head.
5. Remove all objects from mouth that may interfere with exposure.
   * Dentures/Retainers
   * Tongue rings
   * Gum
6. Occlusal Plane parallel to the floor.
7. Place and secure lead apron with thyroid collar on patient.

*DO ALL THIS FIRST - before placing sensor!!! To keep patient from being uncomfortable for longer than necessary

Question 20

Full Mouth Survey (FMS)

Answer 20

a series of images that show all teeth in a patient’s mouth

• a typical FMS on an adult consists of 18-20 images (14 PA’s and 4-6 BW)

Question 21

FMS Exposure Sequence

Answer 21

• a planned sequence helps you avoid missing an area or from exposing the same area twice

1. Anterior PAs
   - Patients more easily adapt to the anterior image receptor
   -patients less likely to gag on receptor
   -receptor is smaller in the anterior position
2. Posterior PAs
   - always begin with the premolar image before the molar, it is easier for the patient and less likely to cause gagging
3. Bitewings
   - Expose premolar bitewings first

**Dentrix software will not follow this recommended series

Question 22

Anterior Exposure Sequence

Answer 22

1. Assemble the anterior XCP instrument.
2. Begin with the maxillary right canine
3. Expose all maxillary anterior teeth from right to left.
4. End with the maxillary left canine
5. Move to the mandibular arch.
6. Begin with the mandibular left canine
7. Expose all mandibular anterior teeth from left to right.
8. Finish with the mandibular right canine

Question 23

Posterior Exposure Sequence

Answer 23

1. Begin with the maxillary right quadrant.
2. Assemble the posterior XCP instrument for this area
3. Expose the premolar view first, then the molar
4. Without reassembling the XCP instrument, move to
   the mandibular left quadrant.
5. Expose the premolar view first, then the molar view
6. Move to the maxillary left quadrant and reassemble
   the posterior XCP instrument for this area.
7. Expose the premolar film first, then the molar film
8. Finish with the mandibular right quadrant.
9. Expose the premolar film first, then the molar film

Question 24

Pregnancy & Xrays

Answer 24

X-rays of your mouth should only be taken in an emergency if the patient is pregnant.

If you need an X-ray, make sure you are covered with a lead apron to protect your baby from radiation

Question 25

Common Receptor Errors

Answer 25

Unexposed Receptor - Clear appearance - failure to turn on the xray machine

Film exposed to light (only occurs with film) - Black appearance - film was exposed to white light

Overexposed receptor - image appears dark or high in density - excessive exposure time, kilovoltage, milliamperage

Underexposed receptor - the image appears light or low in density - the receptor was under exposed

Question 26

Periapical Technique errors

Answer 26

Absence of Apical Structures - no apices appear in the receptor - receptor was not positioned in patients mouth the cover the apical regions of teeth

Dropped Receptor Corner - The occlusal plane appears tipped or tilted - The edge of the receptor was
not placed parallel to the incisal-occlusal surfaces of the teeth

Cone cut - A cone cut is seen when the position-indicating device is not properly aligned with the periappical bean alignment device

Question 27

Angulation Problems

Answer 27

Angulation: Term used to describe the alignment of the central ray of the x-ray beam in the horizontal and vertical planes
a) Can be varied by moving the PID in either a horizontal or vertical direction
i. Horizontal angulation: Refers to the positioning of the PID in a horizontal, side-to-side plane
ii. Vertical angulation: Refers to the positioning of the PID in a vertical, up-and-down plane

1.Dental radiographer must be prepared to choose the correct horizontal and vertical angulations

2.Incorrect horizontal angulation results in overlapped interproximal contacts, and incorrect vertical angulation results in distorted images

Question 28

FMS criteria for BWS

Answer 28

Premolar bite-wing
The resulting image shows both the maxillary and mandibular premolars and distal contact areas of both canines

Molar bite-wing
The resulting image shows both the maxillary and mandibular molars

Question 29

Dexis Mounting

Answer 29

What we do after taking the xrays

-it is important to know how to mount the radiographs in Dexis in order to read the images correctly

Question 30

Digital Mounting

Answer 30

Digital images must also be properly arranged and mounted in anatomical order. Imaging software will either allow you to drag and drop your image into the correct mounting space or the correct space is selected before exposure and the image is placed automatically.

Question 31

Angulation Technique Problems

Answer 31

Overlapped contacts: incorrect horizontal angulation - overlapped contact - caused by the central ray was not directed through interproximal spaces

Foreshortened images: Incorrect vertical angulation - may occur with bisecting technique - short teeth with blunted roots appearance - caused by excessive vertical angulation

Elongated Images: Incorrect vertical angulation - long, distorted teeth appearance - caused by the vertical angulation was insufficient

Question 32

PID Alignment Problems

Answer 32

Cone-cut WITH Beam Alignment Device - A clear area appears on the image - caused by the PID was not properly aligned with the periapical beam alignment device

Question 33

Bite Wing and Misc Technique Errors

Answer 33

Incorrect Receptor Placement of Premolar BW - distal surfaces of the canines are not visible on the image - caused by the BW receptor was positioned too far posteriorly in the mouth

Incorrect Placement of Molar Bitewing - Third molar regions are not visible on image - caused by the BW receptor was positioned too far anteriorly in the mouth

Question 34

Misc Technique Errors

Answer 34

Bending (indirect & film) - Images appear stretched (on film) and distorted (on PSP receptors) - caused by improper handling; receptor damaged

Creasing (indirect & film) - A thin radiolucent line appears on the image - caused by improper handling; receptor creased; film emulsion cracked

Debris Accumulation (digital sensors) - Debris on the surface of sensor may cause permanent radiopaque artifacts or radiolucent scratch marks on sensor - caused by sensors not handed carefully, or wiped between uses; debris/dirt accumulates on the surface of sensor

Phalangioma - (digital or film) - patient’s finger appears on the image - caused by patients finger positioned in front of the receptor

Double image (indirect or film) - a double image appears on the image - caused by the receptor was exposed twice in the patient’s mouth

Movement/Motion unsharpness (digital or film) - blurred images appear on the image - the patient moved during exposure of the receptor

Reversed/Backward Placement (digital or film) - light images with a herringbone pattern appear on the image - caused by the receptor was placed backwards in the mouth and then exposed

• Wired Cable Issues (direct digital only) - cable is seen in the image - caused by the intraoral sensor is linked to computer via fiberoptic cable; if the sensor is placed with the cable between the sensor and the source of radiation, and outline of the cable will be seen