Comparative Analysis of Intraoral Radiographs with Variation of Tube Angulation to Detect Insufficient Crown Margins

Variations in angulation of the x-ray tube affect the appearance of insufficient approximal crown margins on intraoral radiographs. This study examines the impact of such angular variation on the assessment of digital radiographs using three different X-ray tubes - Heliodent DS (Sirona), Gendex Expert DC (KaVo Dental) and Focus (KaVo Dental) - as well as the Gendex Visualix eHD CCD sensor (KaVo Dental). The test specimens, crowned teeth 46 from two mandibles provided by the Institute of Anatomy and Cell Biology, were examined with each tube.The results indicate great differences in the angles indicative of insufficient crown margins on X-ray images. Because of beam divergence and the crown marginal gap, the length and width of which frequently varies, it is difficult to infer any optimum angle from the data. This leads to the conclusion that at present, it is not possible to establish ideal angles for visualization of insufficient approximal crown margins. Keywords: X-ray, intraoral, digital, crown margin, angulation, angle