The optical impression system used for the study is TRIOS (3 shape). First of all, the operators in charge of taking the digital impressions are going to get trained prior the study and will calibrate (learning curve). MIS Scan bodies will be placed on the multi-unit plaforms, an x-ray will be taken in order to check the fit) and the impression will be realised following the instruction given by the system (first the maxillary and mandibular impressions followed by the bite registration). Shade will be chosen using VITA toothguide 3D master (to pick the right zirconia shade).

Once the impression coping is placed on the multi-unit plaform, the fit will be checked with an intra-oral X-ray. The impressions will be made with medium viscosity silicon. As a second step, alginate antagonist impression will be done. Bite will not be recorded (single tooth missing). The two impressions will be placed in a hermetic plastic bag and send to lab. Shade will be chosen using VITA toothguide 3D master.

The implant crowns issued from digital impressions will be done according a cast less / full digital workflow. The STL files collected from the TRIOS will be sent directly to the lab. The designing of the full zirconia crowns will be performed in the TRIOS 3SHAPE program. The resulting files will be sent to the CAM unit production (Amman Girrbach milling machine & MAZAK CNC machine: Mcenter to be specify (Berlin or Israel) to be milled (milled & sintered only) considering the direct adaption for a Multi-Unit connection. A superficial make-up will be done on the monolithic crown in the lab. And finally, the products will be delivered to the dentist.

Each patient will go through both type of impression during single appointment: first the digital impression and then the conventional one (to avoid residual impression materials for the optical impressions). The time necessary for each procedure will be recorded.

To measure this parameter we will focus on interproximal fit and occlusion. Interproximal contact points will be checked with dental floss.

Numbers of appointment needed for each procedure will be counted and each one of them will be timed (from the unscrewing of the healing abutment until its replacement).