Rad Theory W3

Chapters 7, 8, 17, 18, 19

Intra-oral x-ray machines

used to expose intra-oral films

placed inside client’s mouth

Extra-oral x-ray machines

expose extra-oral films

placed outside client’s mouth

Components of an X-ray machine

1. Tubehead (PID)

2. Extension arm

3. Control panel

Control panel

allows radiographer to regulate the x-ray beam

Rinn XCP & BAI Holders

beam alignment devices

XCP bite block

Stabe bite block (disposable)

Extension Cone Paralleling (XCP) Holders

3 in 1 ring

used for paralleling technique

Bisecting Angle Instruments (BAI)

used for the Bisecting Technique

Collimating device

reduces amount of radiation a patient receievs

Unit-bite

universal film holder

can be used with bitewing or paralleling technique

Endoray Film Holder

used during endodontic procedures

Eezee-grip film holder

used in Bisecting technique

double ended

for anterior and posterior

Intraoral sensor

use for paralleling technique

indirect digital radiography

uses phosphor plates that are first exposed then digitally scanned

direct digital imaging

connects direct to the computer via USB, provides an immediate image

Charge coupled device (CCD) sensor

most common image receptor for dental digital radiography

Storage phosphor imaging

records data on plates and uses a scanner to convert into electronic files

what we use!

Pixel

smallest individuual unit of the radiographic image

A digital image is formed from?

a matrix of pixels

Quality assurance

making sure everything is good

Fresh film is?

Clear with a slight blue tint

Expired film is?

fogged

Screens film contact test

image should be uniform density

Viewbox

illuminator; emits a uniform and subdued light when functioning properly

Darkroom

light leak test

coin test

If the density on the standard radiograph matches the density seen on the daily radiograph, the developer solution is?

adequate

Which step on the stepwedge to use for comparison

middle density

Quality administriation programs include:

1. description of the plan and assignment of duties

2. monitoring and maintainence schedule

3. record keeping log of all quality control tests

4. periodic evaluation and revision

5. in-service training

Periapical exam (PA)

used the examine the entire tooth (around the roots)

must show crown and root; 2-3 mm beyond root apex

paralleling or bisecting technique

Interproximal examination

bitewings

must show open contacts; no overlapping

can be used to identify inter proximal caries and the bone level

Occlusal examination

occlusal radiographic technique

bite down on occlusal film

Complete Mouth Radiographic Series

aka Full Mouth Series (FMS)

Extraoral Radiographic Exam

panoramic and cephalometric radiograph

inspect large areas of the cranium or jaws

3 Basic Principles of the Paralleling Technique

1. film & long axis of tooth are parallel

2. central ray perpendicular to the film and tooth

3. film holder must be used to keep film parallel to long axis of tooth

(an increased target film distance is required (16 inches) to reduce magnification)

To acheive parallelism between the film and the tooth, the film must be placed?

away from the tooth and towards the midline of the oral cavity

Increase OFD =

Increase Magnification / Decrease Detail

Increase TFD =

Decreased Magnification / Increased Detail

What size film for posterior PAs?

size 2 for adults; size 1 for children

Vertical angulation

central ray must be directed perpendicular to the film

Horizontal angulation

central ray to be directed through the contact areas between the teeth

Patient prep for paralleling technique

1. “inform before you perform”

2. prepare films and holding devices

3. adjust chair upright and to proper height

4. adjust patient head parallel to floor

5. protect patient with lead apron and thyroid collar

6. remove superimposed objects (glasses)

FMS

Full mouth survey

Cotton rolls can be used?

to compensate for vertical angulation (parallelism)

Torus

bony growth

If a patient has a maxillary torus..

place film on opposite side of palatal torus

If a patient has a mandibular torus..

place film between torus and tongue, making sure it doesn’t rest on top of torus

Advantages of paralleling technique

1. lack of distortion → max detail and definition

2. simple and easy to learn

3. easy to standardize → accurately duplicate