Background: one extracted human mandibular first molars with known dimensions was scanned inorder to create virtual preparation for conventional endocrown with different tapers eight and twelve. Each preparation of different taper was then printed 7 times to be scanned 7 times by reference desktop scanner “InEos X5” (Dentsply Sirona Germany). Followed by scanning of each die using Active triangulation technology Omnicam intraoral scanner (Dentsply Sirona-Germany) and Confocal technology Primescan intra oral scanner ( Dentsply Sirona Germany) . Each scan was checked for trueness using Geomagic reverse engineering software. Results: samples with 12º taper (66.17±17.78) (μm) had significantly higher trueness than those with 8º (91.96±21.31) (μm) (p<0.001). Samples scanned by confocal technology (65.23±16.44) (μm) had significantly higher accuracy than those acquired by triangulation (92.91±21.11) (μm) (p<0.001 Conclusion: 12 degree taper of endocrown gives more true scans than 8 degrees. Confocal IOS are more true than Active triangulation.