Xray - Week 4 PP Flashcards
Bisecting Technique
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”
Bisecting Steps
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
Film holders - for bisecting
EeZee-Grip holder - for digital sensor
Stable Disposable Holder
Rinn BAI Bite-block
Why do dentist requisition bitewings?
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.
BW Radiographs - purpose
Detects interproximal decay
* Detect loss of alveolar bone
* Changes in the pulp
* Overhanging restorations
* Poor Margins on Crowns
* Recurrent decay beneath restorations
Bitewing Film Placement
Bitewings can be taken both vertically and horizontally
Bitewing exposure
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
Vertical Angulation
The vertical angulation of the PID must be at +10 degrees
Horizontal angulation
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
Bitewing sequence
Typically on adults 4 bitewings are taken.
1 pre-molar and 1molar bitewing on each side
Pre-molar bitewing
Must include edges of canines, premolars visible, with open contacts
Molar bitewing
Must include entire lower second molar, open molar contacts, no cone-cuts
Bitewing film sizing
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
Molar Bitewing
Must include distal third molar/wisdom teeth - can be tricky to capture
What is a cone cut?
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
Tips to avoid cone cuts during bitewing exposure / tips for successful bitewing exposure
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
Pre-molar bitewing positioning tips
Make sure the receptor is covering the distal surface of the canines
Molar bitewing
make sure the receptor covers the distal of the second molar (or third molar if they have)
Patient preparation for xrays
- Explain the radiographic procedure(s) to the patient.
- Select the settings on the control panel
- Adjust patient chair so that the patient sits upright
- Adjust headrest to support and position patient’s head.
- Remove all objects from mouth that may interfere with exposure.
* Dentures/Retainers
* Tongue rings
* Gum - Occlusal Plane parallel to the floor.
- 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
Full Mouth Survey (FMS)
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)
FMS Exposure Sequence
- a planned sequence helps you avoid missing an area or from exposing the same area twice
- 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 - Posterior PAs
- always begin with the premolar image before the molar, it is easier for the patient and less likely to cause gagging - Bitewings
- Expose premolar bitewings first
**Dentrix software will not follow this recommended series
Anterior Exposure Sequence
- Assemble the anterior XCP instrument.
- Begin with the maxillary right canine
- Expose all maxillary anterior teeth from right to left.
- End with the maxillary left canine
- Move to the mandibular arch.
- Begin with the mandibular left canine
- Expose all mandibular anterior teeth from left to right.
- Finish with the mandibular right canine
Posterior Exposure Sequence
- Begin with the maxillary right quadrant.
- Assemble the posterior XCP instrument for this area
- Expose the premolar view first, then the molar
- Without reassembling the XCP instrument, move to
the mandibular left quadrant. - Expose the premolar view first, then the molar view
- Move to the maxillary left quadrant and reassemble
the posterior XCP instrument for this area. - Expose the premolar film first, then the molar film
- Finish with the mandibular right quadrant.
- Expose the premolar film first, then the molar film
Pregnancy & Xrays
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
Common Receptor Errors
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
Periapical Technique errors
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
Angulation Problems
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
FMS criteria for BWS
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
Dexis Mounting
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
Digital Mounting
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.
Angulation Technique Problems
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
PID Alignment Problems
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
Bite Wing and Misc Technique Errors
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
Misc Technique Errors
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
