21

Introduction to Dental

Radiography and Equipment

2

Discovery of the X-Ray

• Roentgen 1895– Anode– Cathode

• Walkoff– Dental Radiograph

• Kells– Intraoral Radiograph

3

Discovery of the X-Ray

• Rollins– First dental x-ray unit

• Coolidge– Cathode x-ray tube

• Victor X-Ray Corporation (GE)– Dental x-ray machine

4

X-Ray Techniques

• Bisecting technique

• Parallel technique

• Panoramic technique

• Tomography

• Digital Imaging

5

Radiation Physics and Biology• Electromagnetic energy

– Travels in waves moving in straight line– Travels at the speed of light– Has no mass– Travels through space as transverse

waves

6

Wavelength

• Cycle– Distance between peaks

• Short wavelength

• Long wavelength

7

Radiation Types

• Hard radiation

• Soft radiation

• Four types of radiation– Primary– Secondary– Scatter– Leakage

8

Radiation Units of Measurement

• Roentgen – R

• Radiation absorbed dose – Rad or Gray (GY)

• Roentgen equivalent man – Rem or Sievert (SV)

9

Radiation Units of Measurement

• Milliroentgen – mR

• Relative biological effectiveness – rbe

10

Structure of Atom

• Ionization

• Atoms make up all matter– Protons– Neutrons

• Electrons– Hadrons– Leptons– Quarks

11

Biological Effects of Radiation

• Somatic and genetic effects

• Radiosensitive cells

12

Radiation Exposure

• Occupational exposure

• Maximum Permissible Dose (MPD)

• Daily radiation exposure– Natural – Artificial

• Accumulation of radiation

13

Components of the Dental X-Ray Unit

• Control Panel– Milliamperage– Kilovoltage (KV)– Electronic Timer– Milliamperage Seconds– Contrast– Density

14

Components of the Dental X-Ray Unit

• Arm assembly and tubehead– Arm Assembly– Tubehead– X-ray Tube (Coolidge Tube)– Filter– Central Beam– Collimator

15

Safety Precautions

• Responsibilities for safety– Manufacturers– Dentist– Dental Assistant– Patient

16

Radiation Production

• Thermionic Emission– Electrons given off when the filament is

heated to a certain temperature– Electrons travel from cathode to anode– X-rays produced when electrons collide

17

Dental X-Ray Film

• Composition

• Film speed

• Film size

• Dental film pack

• Dental film storage