Ambient light can damage PSP image quality – Revenge of the sensors

There are two basic means to acquire a digital image:

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  Direct: This is the fastest method to acquire an image and requires a specially coated electronic receptor, called a sensor, which records the image. The sensor is placed in the oral cavity in a similar manner as you would place a film packet. When exposed to x-radiation, the sensor converts the x-rays to an electronic form that is read by the computer almost immediately. Intraoral sensors are comparable in size to an intraoral film packet and may be wired or wireless. Wired sensors are connected to the computer via a fiberoptic cable and wireless sensors communicate with the computer via a radio frequency. (Currently only Schick Technologies sells a wireless sensor.)

• Semi-indirect: This method requires a special sensor called a photostimuable phosphor plate (PSP) and a special scanner. The sensor is coated on one side with reusable phosphorus that stores the x-radiation until a scanning device converts it into a digital image. The PSP plate looks and handles like dental film, and the image is acquired when exposed to x-rays. Step two involves placing the plate in a special scanner, specific to the imaging software, to convert it to a digital image. This method is not as fast as the direct method, but quicker than the indirect method. The image stored on the plate is erased by exposing it to bright light. Once the plate is cleared, it can be used again. Some systems offer a scanner that also clears the plate, while other systems require the plate to be placed separately in bright light.