Age Groups and Radiographs

• Age 2:

  • Anterior IOPA's: 2
  • Posterior IOPA's: 4
  • Bitewings: 2
  • Total Films: 12

• Age 8:

  • Anterior IOPA's: 8
  • Posterior IOPA's: 4
  • Bitewings: 2
  • Total Films: 14

• Age 8 (another entry):

  • Anterior IOPA's: 8
  • Posterior IOPA's: 8
  • Bitewings: 2
  • Total Films: 20

Summary of Total Films by Type

• Anterior IOPA's:

  • Age 2: 2
  • Age 8: 8
  • Age 8 (another entry): 8
  • Total Anterior IOPA's: 18

• Posterior IOPA's:

  • Age 2: 4
  • Age 8: 4
  • Age 8 (another entry): 8
  • Total Posterior IOPA's: 16

• Bitewings:

  • Age 2: 2
  • Age 8: 2
  • Age 8 (another entry): 2
  • Total Bitewings: 6

Overall Total Films

• Total Films for Age 2: 12
• Total Films for Age 8 (first entry): 14
• Total Films for Age 8 (second entry): 20
• Grand Total Films: 12 + 14 + 20 = 46

Radiographic films used in Dentistry

1. Intraoral Periapical (IOPA) Film

• Size 0:
  • Dimensions: 22 x 35 mm
  • For: Small children
  • MPD (Maximum Permissible Dose) for whole body: 0.1 Rem in 1 year
• Size 1:
  • MPD for gonads/bone marrow: 0.5 Rem in 1 year
• Size 2:
  • Dimensions: 24 x 40 mm or 32 x 41 mm
  • For: Anterior projections and adults
  • MPD for gestation period in relation to the fetus: 5 Rem
  • MPD for skin: 0.5 Rem in 1 year
• Radiation Exposure:
  • Mean exposure from one IOPA: 300 mR
  • Mean exposure from improved dental X-ray techniques: as low as 110 mR

2. Bitewing Film

• Size 0:
  • For: Very small children
• Size 1:
  • For: Children
• Size 2:
  • For: Adults

3. Occlusal Film

• Size:
  • 3 times larger than size 2 film (57 x 76 mm)
  • Used for capturing larger areas of the dental arch.

4. Screen Film

• Size:
  • 8 x 10 inches
  • Used for extraoral projections in conjunction with an intensifying screen.

Additional Information

• Erythema Dose: The amount of radiation necessary to produce a noticeable skin reaction, typically 300-400 R.
• ALARA Principle: Stands for "As Low As Reasonably Achievable," emphasizing the importance of minimizing radiation exposure.

General guidelines for vertical angulations for common dental radiographs in children:

Anterior Teeth

1. Maxillary Central Incisors:
   • Vertical Angulation: +40 to +50 degrees
2. Maxillary Lateral Incisors:
   • Vertical Angulation: +40 to +50 degrees
3. Maxillary Canines:
   • Vertical Angulation: +45 to +55 degrees
4. Mandibular Central Incisors:
   • Vertical Angulation: -10 to -20 degrees
5. Mandibular Lateral Incisors:
   • Vertical Angulation: -10 to -20 degrees
6. Mandibular Canines:
   • Vertical Angulation: -15 to -25 degrees

Posterior Teeth

1. Maxillary Premolars:
   • Vertical Angulation: +30 to +40 degrees
2. Maxillary Molars:
   • Vertical Angulation: +20 to +30 degrees
3. Mandibular Premolars:
   • Vertical Angulation: -5 to -10 degrees
4. Mandibular Molars:
   • Vertical Angulation: -5 to -10 degrees

RELATIVE RADIO SENSITIVITY OF THE TISSUES

Radiosensitive (2500 r or less kills or seriously injures many cells)

Lymphocytes and lymphoblasts
Bone marrow (myeloblastic and erythroblastic cells)
Epithelium
Germ cells (testes and ovary)

Radioresponsive (2500-5000 r kills or seriously injures many cells)

Epithelium of skin and many appendages.
Endothelium of blood vessels
Salivary glands
Growing bone and cartilage.
Conjunctiva, cornea and lens of eye
Collagen and elastic tissue(fibroblasts themselves are resistant)

Radioresistant (over 5000 r are required to kill or injure many cells)

Kidney
Liver
Thyroid
Pancreas
Pituitary
Adrenal and parathyroids
Mature bone and cartilage
Muscle
Brain and other nervous tissue.

The numbers represent the minimum damaging doses; a gray and a sievert represent roughly the same amount of radiation:
• Fetus--2 grays (Gy).
• Bone marrow--2 Gy.
• Ovary--2-3 Gy.
• Testes--5-15 Gy.
• Lens of the eye--5 Gy.
• Child cartilage--10 Gy.
• Adult cartilage--60 Gy.
• Child bone--20 Gy.
• Adult bone--60 Gy.
• Kidney--23 Gy.
• Child muscle--20-30 Gy.
• Adult muscle--100+ Gy.
• Intestines--45-55 Gy.
• Brain--50 Gy.
 

Common Problems in Film Processing

1. Light Radiographs

• Causes:
  • Under Development:
    • Temperature too low
    • Time too short
    • Depleted developer solution
  • Under Exposure:
    • Insufficient milliamperage
    • Insufficient kVp
    • Insufficient exposure time
    • Film-source distance too great
    • Film packet reversed in the mouth

2. Dark Radiographs

• Causes:
  • Over Development:
    • Temperature too high
    • Time too long
    • Accidental exposure to light
    • Improper safe lighting
    • Developer concentration too high
  • Over Exposure:
    • Excessive milliamperage
    • Excessive kVp
    • Excessive exposure time
    • Film-source distance too short

3. Insufficient Contrast

• Causes:
  • Improper processing conditions (under or over development)
  • Depleted developer solution
  • Contaminated solutions

4. Film Fog

• Causes:
  • Excessive kVp
  • Improper safe lighting
  • Light leaks in the darkroom
  • Contaminated developer solution

5. Dark Spots or Tines

• Causes:
  • Contaminated solutions
  • Film contaminated with developer before processing
  • Film in contact with tank or another film during fixation

6. Light Spots

• Causes:
  • Insufficient washing
  • Film contaminated with fixer before processing
  • Film in contact with tank or another film during development

7. Yellow or Brown Stains

• Causes:
  • Insufficient washing after fixation
  • Depleted fixer solution
  • Contaminated solutions

8. Blurring

• Causes:
  • Movement of the patient during exposure
  • Movement of the X-ray tube head
  • Double exposure
  • Misalignment of the X-ray tube head (cone cut)

9. Partial Images

• Causes:
  • Top of film not immersed in developing solution
  • Film in contact with tank or another film during processing

10. Emulsion Peel

• Causes:
  • Excessive bending of the film
  • Improper handling of the film

11. Static Discharge

• Causes:
  • Static discharge to film before processing (results in dark lines with a tree-like image)

12. Fingerprint Contamination

• Causes:
  • Fingerprint contamination during handling of the film

13. Excessive Roller Pressure

• Causes:
  • Excessive roller pressure during processing can lead to artifacts on the film.

DENTAL X-RAY TUBE

The dental X-ray tube is surrounded by a glass envelope that houses a vacuum.
The glass prevents low-grade radiation from escaping. The vacuum insures the protection of the equipment from catastrophic failure. Production of X-rays generates enormous amounts of heat; the vacuum prevents the risk of combustion and ensures the proper environment for conduction of electrons.

There are two separate energy sources, one that powers the energy potential between the cathode ?lament and the anode, and the other being
the controls for the cathode ?lament. The latter essentially is the on and off switch of the X-ray unit.

The cathode ?lament is heated which causes electrons to be emitted.

These electrons are then accelerated by the electrical potential of the circuit.

Between the two points is a tungsten target.
When electrons strike the target, X-rays are produced.

HALF-VALUE LAYER

- Property of a material whereas the thickness (mm) reduces 50% of a monochromatic X-ray beam.
- Half-value layer of a beam of radiation from an X-ray unit is about 2 mm of aluminum (Al).

PRIMARY RADIATION

- Is the main beam produced from the X-ray tube. 

SECONDARY RADIATION

- Produced by the collision of the main beam with matter which causes scatter.