Cone beam computed tomography (CBCT) is the modern third dimension applied in the field of oral maxillofacial region. With lower radiation dose compared to conventional CT, its applications in dentistry has increased tremendously. Artefacts can seriously degrade the quality of computed tomographic (CBCT) images, sometimes to the point of making them diagnostically unusable. To optimize image quality, it is necessary to understand why artifacts occur and how they can be prevented or suppressed. CT artifacts originate from a range of sources; physical based, scanner based and patient based. This article highlights the causes of artefacts on CBCT images and methods to avoid them.