Initial situation

The patient, a 61-year-old man, arrived at our practice reporting an almost completely edentulous mandible. He stated that this situation had become untenable from both a functional and aesthetic perspective. He was therefore seeking for a full arch restoration. His dental history revealed the loss of two fixed bridges on natural teeth due to periodontal disease. In the clinical examination, only tooth 43 was present. It was also periodontally compromised to a great extent. His medical history was unremarkable and did not show any contraindications for implant placement.

Treatment planning

Following the radiographic assessment (Fig. 1), tooth 43 was extracted and a removable full mandibular denture was fabricated. Panoramic radiographs taken nine weeks after extraction showed a well-healed extraction socket in the region of 43 and vertical bone availability (Figs. 2 - 3). Four 8 mm long implants were selected for insertion in the locations 35-32-42-45, in order to support a U-shaped Dolder bar (macro). BLX Implants Ø 3.75 mm were chosen as they allow for the achievement of optimal primary stability and immediate loading.

Surgical technique

The surgical procedure was performed 11 weeks after extraction under local anesthesia. A crestal incision was made in each mandibular quadrant in order to raise a mucoperiosteal flap. The four implant beds were prepared according to the manufacturer's instructions for the insertion of the Straumann^® BLX Implants (Roxolid^®, SLActive^®, Ø 3.75 RB/8 mm) up to drill no. 3 (Ø 3.2 mm). Primary stability was obtained for the four implants. The torque applied was greater than 35 Ncm in each case, thus allowing for immediate loading (Figs. 4 - 5).

Prosthetic procedure

Four straight Straumann^® screw-retained abutments (angulation 0°, Ø 4.6 mm, gingiva height 2.5 mm) were inserted and hand-tightened. The gold copings for screw-retained abutments (Ø 4.6 mm, height 5.5 mm) were placed on the abutments. The two sites were then sutured with non-absorbable nylon sutures (Figs. 6 - 7).

Holes were drilled in the removable full mandibular denture so that the denture would fit tightly without any interference with the copings (Figs. 8 - 9). A reline impression was taken directly on these copings using a fast-setting, addition-curing silicone (Fig. 10). The copings and abutments were then removed and replaced by healing abutments with the same emergence profile as the abutments (Fig. 11).

The U-shaped Dolder bar (macro) was fabricated in the laboratory by welding the bar onto the copings (Fig. 12). Retentive elements were placed on the inner aspect of the full denture (Fig. 13).

Less than 24 hours after implant insertion and fabrication of the bar construction, the abutments were screwed onto the four implants with a torque of 15 Ncm. This was done without causing the implants to move (Fig. 14) or any other symptoms. The bar was screwed (Fig. 15), and the fit was checked with intraoral radiographs. The full mandibular denture could then be inserted with good retention and in correct occlusion. Healing was uneventful (Fig. 16) and the sutures were removed after seven days. The patient's subsequent clinical progress was also free of complications. During the check-up, which took place two months after implant insertion, the abutments were tightened to 35 Ncm and the bar to 15 Ncm (Figs. 17 - 18).

Final result

Straumann^® BLX Implants (Roxolid^®, SLActive^®, Ø 3.75 RB/8 mm) were used since they provide good primary stability and secure immediate loading. The patient was very satisfied with the quick treatment, the minimal postoperative symptoms and the good stability of his bar-borne full mandibular denture.

Acknowledgments

Andreas Fiebig, dentist, Switzerland
Emcolab-Dental Sàrl, Switzerland