This study will be conducted on patients requiring single implant replacement in the posterior regions of the mandible, admitted to the Outpatient Clinic of Fixed Prosthodontics Department, Faculty of Oral and Dental medicine, Cairo University.~Examination and diagnosis:~Selection and examination of the patients according to inclusion and exclusion criteria.~Preoperative Cone Beam Computed Tomography (CBCT) to all patients.~Primary impression will be taken to produce study cast.~Taking a professional photo for the examined posterior area.~Patients will be divided into two group:~G1: Short implants will be restored by screw retained Hybrid ceramic crowns G2: Short implants will be restored by screw retained Lithium Di silicate based ceramic crowns~Surgical procedures:~Implants will be placed following standardized protocol.~After 4 months the patients re-attended for placement of healing abutments for about (10-14) days and prosthesis fabrication.~Data collection and post operative radio-logical assessment:~-Taking standardized digital peri-apical radio-graph by paralleling technique and film holding device for follow up at 12 months after crowns loading to evaluate crestal bone loss.
The aim of the study is to evaluate the crestal bone loss developed around short dental implants after using screw retained Hybrid ceramic crowns when compare to screw retained Lithium Di silicate based ceramic crowns.