Accuracy of Different Impression Techniques on The Fit of Screw-Retained Bar Joining Two Interforaminal Implants

Abstract

This study was a case control study conducted to compare between the accuracy of two different impression techniques on the fit of screw-retained bar joining two interforaminal implants. This study included eighteen completely edentulous patients. Patients were selected from the Outpatient Clinic, Removable Prosthodontics Department, Faculty of Dentistry, Ain-Shams University. Complete denture was constructed for each patient. A CBCT was made for each patient to place two interforaminal implants that were splinted by a screw retained bar. Two screw retained bars fabricated by two different techniques were made for each patient. In the first technique, open top impression was made and master cast was poured on which wax pattern was made. Then, cast screw-retained bar was fabricated through casting procedure. In the second technique, digital impression was made by scanning the two implants intraorally using intraoral scanner. Then, STL file was exported to the milling machine to fabricate milled screw-retained bar. Passive Fit of each bar was evaluated intraorally using screw resistance test. Each bar was screwed to the implants and Torque was measured for right and left screws of each bar using electronic motor. This torque at which full settling of the screws occurred was known.