Additive manufacturing technologies are increasingly used for medical purposes. However, questions are regularly raised about the accuracy of the anatomical models thus obtained. The present study compares two investigative methods that are used for assessing the degree of trueness of 3D printed replicas and presents recommendations for future analyses. The two techniques compared are optical surface scanning by structured light (OSS) and micro-computed tomography (μCT). The comparison was made by investigating an original cranial vault and its replica obtained by selective laser sintering (Eosint P 385, EOS GmbH, Krailling, Germany). OSS tests were conducted using a kolibri Cordless scanner (Fraunhofer IOF, Jena, Germany); μCT was performed with a vǀtomeǀx 240/180 machine (phoenixǀx-ray, GE, Wunstorf, Germany). The degree of trueness of the replica was assessed with an iterative closest point algorithm (Geomagic Qualify software, Version 12, Geomagic GmbH, 3D Systems, Rock Hill, USA).The replica's deviations from the original, measured by OSS and μCT, respectively, were as follows: Homogeneous enlargement factor: 1.3% vs 1.2%; Mean shape deviation: +0.27mm (±0.15mm) vs +0.24mm (±0.23mm); Shape deviation <1.0mm: 99.95% vs 99.35%; Maximum positive shape deviation: +1.62mm vs +1.43mm; Maximum negative deviation: -1.65mm vs -3.51mm. Considering the coherent results obtained, we conclude that both OSS and μCT are appropriate for quantitative evaluation of 3D printed preoperative models. For objects with complex geometry, which are to be examined not only with respect to their visible surface, μCT is recommended. For highly x-ray absorbent materials and authentic bone material, OSS is preferable.