The patients were screened with preliminary panoramic radiographs, and since all the implants were 3D planned (SKYplanX™ program, Bredent GmbH, Senden, Germany) and inserted with a guiding template, a cone-beam CT (CBCT) was obtained eventually (KaVo 3D eXam™ unit, KaVo Dental GmbH, Biberach/Riss, Germany).

The drillings were performed using a 3D-planned surgical template with different metal sleeves corresponding to the diameter of the drills (Fig. 1). Implants were inserted torque controlled under vision without the surgical template. Primary implant stability was assessed immediately following implant insertion by PT (Medizintechnik Gulden, Modautal, Germany) and RFA (Osstell, Gothenburg, Sweden).

Definitive titanium abutments (0°, 17.5°, 35°; fast & fixed abutments, Bredent, Senden, Germany) were attached to the implants. The abutment screws were tightened with a torque of 25 N cm. On these abutments, impression copings for closed trays were seated and an impression and a provisional inter-jaw relationship recording with a silicone were performed.

After cast making, temporary resin prostheses using a composite veneering system (visio.lign, Bredent, Senden, Germany) were prepared in the laboratory (Fig. 2). These temporary restorations were perforated in five of the six implant regions. After the temporary prosthetic titanium cylinders (Bredent, Senden, Germany) were attached on the abutments and the resin superstructures were placed over the cylinders, the superstructure perforations were filled with self-curing resin (Qu-resin™; Bredent, Senden, Germany) (Fig. 3). The superstructure was removed, completed, and relined. The provisional restoration was inserted, the screw holes were sealed, and the denture was adjusted on the occlusal plane. All provisional prostheses were inserted on the same day of implant insertion. With the provisional restorations, no further distal tooth was replaced than that under which the distal implant was positioned. Therefore, the distal cantilever extensions of the provisional prosthesis have not exceeded the width of a half molar.

Three months post-surgery, the temporary restorations were removed for the first time (Fig. 4), ISQ and PT values were measured, and the final prosthetic protocol was performed if all implants were osseointegrated.