How does the film used in extra oral radiographs differ from that used for intra-oral radiographs?

Extraoral and intraoral radiographs use different types of film due to the different requirements and techniques used in each method.

1. Size: The film used in extraoral radiographs is larger compared to that used in intraoral radiographs. This is because extraoral radiographs need to capture a larger area, such as the entire jaw or skull, while intraoral radiographs focus on individual teeth or small groups of teeth.

2. Sensitivity: The film used in extraoral radiographs is less sensitive to radiation compared to intraoral film. This is because extraoral radiographs are taken from outside the mouth and thus require a higher dose of radiation to penetrate through tissues and bones. On the other hand, intraoral radiographs are taken from inside the mouth and require a lower dose of radiation.

3. Packaging: Intraoral film is typically enclosed in a waterproof plastic packet to protect it from saliva and moisture in the mouth. Extraoral film does not require this type of packaging as it is not placed inside the mouth.

4. Placement: Intraoral film is placed inside the mouth and the patient bites down on it to hold it in place. Extraoral film is placed outside the mouth, often in a holder or cassette, and does not require the patient to bite down on it.

5. Image Quality: Extraoral films generally provide a broader view but with less detail, while intraoral films provide a more detailed view of a smaller area.

In conclusion, the main differences between the film used in extraoral and intraoral radiographs are their size, sensitivity to radiation, packaging, placement, and the quality of image they produce.