Composition Of Dental X-Ray Film: Film Base To Protective Layer

Composition Of Dental X-Ray Film: Film Base To Protective Layer

Write a short note on the composition of intraoral X-ray film.
or
Write a short note on the composition of X-ray film.
Answer. X-ray film or intra-oral X-ray film used in dentistry consists of four basic components:

• Film base
• Adhesive layer
• Film emulsion
• Protective layer

Film Base

• It is a transparent supporting material upto which the emulsion is coated.
• Film base is a flexible piece of polyester plastic, i.e., polyethylene terephthalate, which is 0.2 mm in thickness and is constructed to withstand heat, moisture, and chemical exposure.
• It exhibits a slight blue tint, which is used to emphasize contrast and enhance image quality. It also provides optimal viewing conditions.
• The main objective of the film base is to provide stable support for delicate emulsion.
• Film base also provides the strength.

Adhesive Layer

• The adhesive layer is a subcoating that consists of a thin layer of adhesive material that covers both sides of the film base.
• An adhesive layer is added to the film base before the emulsion is applied, and it ensures good adhesion between the sensitive emulsion and the film base.

Composition of X-ray film

Film Emulsion

• Film emulsion is coated on both sides of the film base to provide the film greater sensitivity towards X-ray radiation.
• Emulsion is a homogeneous mixture having two principal components, i.e., silver halide crystals and Gelatin matrix
• Silver halide crystals: Halide is a chemical compound that is sensitive to radiation or light. Halides used in intra-oral X-ray film are made up of the element silver and a halogen (bromine or iodine).

X-ray film structure

• • Silver bromide and silver iodide are two types of silver halide crystals present in the film emulsion. Typical emulsion is 80 to 99% silver bromide and l to 10% silver iodide. The presence of silver iodide aids in the sensitivity of the film emulsion and decreases the radiation dose which is required to produce an adequate diagnostic image.
  • Silver halide crystals absorb radiation at the time of X-ray exposure and store energy from the radiation.

Dental X-ray film layers

• Gelatin matrix: Gelatin is used to support silver halide crystals, which are suspended in a gelatin framework over the film base. At the time of film processing, gelatin absorbs the processing solutions and permits the chemicals to react with the silver halide crystals.

Protective Layer

• It is a thin, non-abrasive, transparent supercoat placed over the emulsion.
• It protects the emulsion surface from manipulation as well as mechanical and processing damage by forming an additional layer of gelatin.