Typical types of images in routine dental practice include full face, frontal view of dentition, full arch (occlusal), groups of teeth and single teeth. As mentioned earlier, a single lens can not produce optimal results for all views. If a single-lens system is mandatory, it is best to choose a system that performs satisfactorily for intraoral views. For external views, a digital camera can be used.

Lenses for intraoral use should have a large enough zoom range to optimize viewing a single tooth, as well as a group of teeth. The larger the viewing angle, the greater is the area the camera can image from a given distance. For instance, it is easier to record a full arch image with a camera with a larger viewing angle. Unfortunately, a larger viewing angle increases the distortion of an image, especially in its periphery.

To be added: sample images illustrating varying degrees of distortion.

Maximizing the depth of field is especially important for intraoral images. The smaller the aperture, the larger the depth of field. The smallest aperture feasible depends on the degree of illumination of the scene. A brighter light source allows the operator to choose a smaller aperture, resulting in a larger depth of field. However, increased illumination also tends to increase the image contrast. Lighted areas appear brighter and shaded areas darker. This makes exposure problematic. Overexposed areas can result in “blooming,” i.e. groups of false-colored pixels in the image.

To be added: sample images illustrating correct exposures and blooming.

Thus, taking optimal images involves careful balancing of lens properties, illumination and aperture. Since some (or all) of these parameters allow no adjustment (depending on the camera model), it is important to test a camera under realistic conditions.

The resolution of a camera is typically expressed as the line pair count. Explanation to be added.

Question: Why is a small aperture important when taking pictures with an intraoral camera? Question: Identify the appropriate image that illustrates blooming, distortion, overexposure.