The study's objective was to assess the clinical behavior of monolithic zirconia crowns with two different margin designs in terms of fracture during a one-year period. Forty-four posterior endodontically treated molars received full coverage monolithic crowns. The teeth were separated into two groups depending on the margin design: the control group (RS) had a rounded shoulder finish-line while the intervention group (F) had a feather-edge finish-line. An intra-oral scan was used for the full coverage restorations, which were designed using open source software and machined on a 5 axis machine. The crowns were sandblasted and cemented with conventional glass ionomer cement. The modified United States Public Health Service (USPHS) criteria were used to assess clinical behavior in terms of fracture following cementation. The grades were immediately taken after cementation and at three consecutive three-month follow-up assessments over the course of a year. In terms of restoration fractures, all three follow-up examinations yielded a perfect Alpha score of 100 percent for each group. (P<0.05) There was no statistically significant difference between the control (RS) and intervention (F) groups. In this one-year randomized clinical investigation, all of the crowns assessed were clinically successful, with no signs of fractures.