Radiographic Films and Accessories
Radiographic films and accessories such as cassettes, film holders and grids are essential in every day dental practice. Use of appropriate accessories will help in improving diagnostic quality of the films, enhance patient care and aid in improving work efficiency.
These films are used for periapical, bitewing and occlusal radiography. These are also referred to as direct action films (primary sensitive to X-rays) and non-screen films (not used in combination with intensifying screens).
The outer protective jacket is essentially made of light proof and moisture proof soft vinyl. A recent development is the use of phthalate free film packets which are otherwise considered potentially harmful to health.
The outer jacket is dual colored. The tube side of the film packet is white colored and the opposite side is twin colored. The cover is sealed to prevent contamination of the film from moisture, exposure to light and ingress of oral fluids when placed in the mouth. The packet on the non-tube side has a flap which is pulled open in the darkroom to remove the exposed film for processing.
The outer jacket (on the tube side/white surface) is incorporated with a raised dot, which relates with a similar area on the dental film inside the packet. This dot aids in orientation of the film during the exposure (always places such that the dot lies closer to the incisal or occlusal aspect of the teeth). Once the film is processed the orientation of the raised dot is used to identify the left and right sides of the patient.
Once the outer jacket is opened a thin sheet of lead foil is seen. This lead foil has parallel indentations or markings along the surface in one corner of the foil. If the film is exposed placing the wrong side toward the tube head, these markings are seen on the resultant radiograph. If the wrong side of the film is exposed, though the radiograph will reveal an image, the image will appear light. The markings on the film will help to identify the cause for the underexposed or light radiograph. These markings (diamond markings) are seen on the resultant radiograph. Lead foil is incorporated into the film packet to:
Minimize the amount of X-rays from passing through the film and interact with the tissues beyond the film and reflect back leading to multiple exposures, thereby minimizing the quality of the final image.
Once the lead foil is folded back, the black paper wrapper is seen in which the film is placed. The paper wrapper protects the film from extraneous visible light and protects the emulsion of the dental film during handling and storage. It also helps in absorbing any moisture created within the film packet as a result of humid storing conditions.
The film has a raised dot on one side and the other side has a small concave depressed area. The film holder used for processing is clipped onto the film conforming to the depressed shallow concave area. This allows a one-point contact between the clip and the film. The advantage of this one-point contact is that processing solutions freely flow into the shallow depression on the film, thereby exposing every single area of the film. Holding the film in any other area will obscure the diagnostic details on the film.