Hard- and Soft-Tissue Cephalometric Landmark Detection when Using a Thyroid Lead Shield

Introduction: The aim of this study was to assess the detection of some hard- and soft-tissue cephalometric landmarks when using a thyroid lead shield. Materials and Methods: Two study groups were designed, and each group consisted of 50 cephalograms: the first group was without thyroid shield cephalograms and the second group consisted of cephalograms taken using a lead thyroid shield. An observer blinded about the aim of the study was appointed to identify 12 landmarks on the lateral cephalograms. Results: Out of 12 of landmarks, 3 landmarks had a significant relationship with the thyroid shield group. Landmarks of cervical point, second and third vertebrae were not detected in 20%, 30%, and 66% of cases, respectively. Discussion: Two hard-tissue landmarks (second and third vertebrae) and one soft-tissue landmark (cervical point) were masked by the thyroid shield when preparing a cephalogram.