The disturbing artefacts from fillings in teeth were experimentally studied. Pins of amalgam and composite with different diameters were scanned in 10 mm and 5 mm slices. Amalgam gave five different artefacts: (1) blackout, (2) tuning fork artefact, (3) star-burst, (4) collimation artefact in the narrow slice and (5) connecting line artefact. The composite material with an attenuation of about 5000 HU gave no blackout and mild degree of the other artefacts except for the collimation artefact, which was equal to that with amalgam.