In a dental cone beam computed tomography (CBCT) machine, the "MAR" (metal artefact reduction) function is a feature that is designed to reduce the impact of metal objects on the images produced by the machine. This is especially useful in cases where the patient has metal restorations or other metal objects in the mouth, as these can cause significant artefacts on the CBCT images.
The MAR function works by applying a special algorithm to the raw data obtained from the CBCT scan. This algorithm is designed to identify and correct for the presence of metal in the images. It does this by analysing the data and determining the location, shape, and composition of the metal objects, and then using this information to create a "virtual metal object" that can be used to correct the images.
The MAR function is typically used in conjunction with other image processing techniques, such as scatter correction, to further improve the quality of the images. It is an important tool for dental practitioners, as it helps to ensure that the CBCT images are accurate and reliable, even in the presence of metal objects.