Initial situation

A 53-year-old patient, smoker, with good hygiene and without parafunctional habits, came to the clinic requesting the replacement of the missing premolars and molars in his left mandible (Fig. 1). The patient had had metal-ceramic restorations in the past and was dissatisfied with the experience, complaining about “a grey metal margin that became visible with time” and looked unesthetic. The patient had done extensive research on the internet and wanted to have a natural-looking, metal-free restoration that would nevertheless be strong and reliable. He was also concerned about the surgery itself and had a strong preference for a minimally invasive surgical procedure.

Treatment planning

During a discussion with the patient and his endocrinologist it was decided that the Straumann® PURE Monotype ceramic implants with a full-ceramic 3-unit bridge, in this clinical case, would provide a metal-free, esthetic and mechanically strong restorative solution. It was also agreed to use a fully guided surgical approach to avoid incisions and minimize surgical trauma. The patient was referred for computed cone beam tomography of the area, and we performed a digital scan using an intraoral scanner (3Shape Trios 3). Upon receipt, the DICOM data was imported into the implant planning software (coDiagnostiX®), while the scan files were imported into the laboratory software (Straumann® CARES® Visual). Since Straumann® PURE ceramic implants are monobodies in design and modification of the abutment is not recommended, our task was to plan the most parallel installation of implants relative to each other, taking into account all anatomical formations (Figs. 2,3). Once the planning was completed, the guided surgery template was 3D-printed (Figs. 4,5)

Surgical procedure

At the first stage, the surgical template was applied and the precision of its fit was checked (Fig. 6). The fixation pin drilling and insertion was then done while the infiltration anesthesia was topped up (Figs. 7,8). The first instrument used was a mucosa punch to facilitate an optimal soft tissue cuff and reduce trauma (Fig. 9).

The Straumann® PURE ceramic implant design is a combination of a tissue level and bone level implant - the implant neck mirrors the Straumann® Tissue Level implant, while the implant body mimics the Straumann® Bone Level design. Thus, the surgical protocol for osteotomy preparation for PURE is the same as for the corresponding bone level implant. For this case, the osteotomy preparation guide was used according to the protocol established for bone level implants provided by coDiagnostiX® (Figs. 10-15). The basic implant bed preparation was done using the pilot drills, followed by the twist drills: for the 3.3 mm implant the final drill was Ø 2.8 mm, for the 4.1 mm diameter implant the final drill was Ø 3.5 mm. The final implant bed preparation was done using the respective profile drills and taps for the 3.3 mm and 4.1 mm diameter implants.

The Straumann® PURE Ceramic Implant comes with a separate transfer piece that locks securely into place (Figs. 16-18). Three points on the driver line up with the flat surface of the implant abutment and also indicate the distance to the shoulder (1, 2 and 3 mm) (Figs. 19,20). This design greatly facilitates implant placement and makes it very straightforward. The Straumann® PURE Ceramic Implant (Monotype) - Ø 3.3 mm ND, ZLA® 12 mm, AH 5.5 mm, ZrO2 and Straumann® PURE Ceramic Implant (Monotype) - Ø 4.1mm RD, ZLA® 12 mm, AH 5.5 mm, ZrO2 were placed in positions of the first premolar and second molar respectively. The implants were precisely installed in the planned position both in terms of the insertion depth and relative to the center of the sleeve (Figs. 21,22).

Prosthetic procedure

Since good primary stability was achieved (about 45 Ncm) and there were no teeth in the maxilla, it was decided to take the closed tray impression immediately after the surgery and fix the implant analogs already in the clinic (Figs. 23,24). An appropriate protective cap was placed on the abutment portion of the implant (Fig. 25). The impressions were transferred to the laboratory, and a one-piece anatomical bridge made of zirconium dioxide was fabricated within 4 working days (Figs. 26,27). After 5 days, the patient came to the clinic for the fixation of the final restoration. At this appointment plaque was seen on the protective caps (Fig. 28), while the healed mucosa looked a healthy pink color (Fig. 29). The abutment part of the Straumann® PURE ceramic implant was cleaned and prepared for cementation. Excess cement was removed (Fig. 30). A follow-up visit was arranged 7 days after cementation. No further crown adjustments were required, and the patient was very satisfied with the final reconstruction.

Treatment outcomes

No biological or technical complications were observed at the one-year follow-up. The treatment option with Straumann® PURE ceramic implant and a zirconia restoration appears to be a valid alternative to titanium implants in patients requiring metal-free restoration. The soft tissues around the implant remained stable over time, indicating the excellent biocompatibility of the zirconia ceramic. The tissue level design of the implant coupled with the tooth- colored body means that the cementation line can be at, or above, the gingival margin, thereby facilitating hygiene maintenance while still achieving an excellent esthetic result. The patient was satisfied with the functional and esthetic outcomes.

Acknowledgements

The restorations were made by Albert Latypov, a dental technician at the Werk dental laboratory (Yekaterinburg, Russia).