Evaluation of colour change, marginal adaptation, fracture strength, and failure type in maxillary and mandibular premolar zirconia endo-crowns oleh Mohammed Y Tarrosh, Mohammed M Al Moaleem, Aalaa Ibrahim Mughals, Raghad Houmady, Asma A. Zain, Alkhansa Moafa, Maram A. Darraj, Loay Ebrahim Najmi, Hashim A Bajawi, Shaima Abdoh Mohammed, Mohmed Isaqali Karobari