A clinical case report by Michael Kristensen, Denmark
This case describes the successful rehabilitation of a fully edentulous mandible and maxilla using the Straumann® Novaloc® Retentive System for hybrid dentures. The use of angulated abutments allowed for appropriate correction of the denture insertion path, hence the excellent final result.
The patient, a 62-year-old male, smoker, had a dentition with a deep bite, heavy wear and severe chronic periodontitis (Fig. 1) The patient had taken a long time to decide between fixed and removable solutions. Several options were discussed – from a full fixed bridge (Straumann® Pro Arch concept) to a set of dentures. In view of the history of periodontitis, a removable prosthesis with Novaloc® abutments was chosen to ensure good retention and easy access of cleaning around the implants. Raising the bite was also planned in the final prosthesis to improve esthetics and function.
The patient’s priority was to establish a permanent function with a minimum of aftercare. Upper and lower impressions were taken, and the smile and occlusion were managed with a set of provisional dentures during the healing period. The treatment plan for the mandible included immediate implant placement following the extraction of the hopeless dentition. The Straumann® Bone Level Tapered (BLT) implant in combination with the good bone quality in the mandible produced a high degree of primary stability. Two lateral / distal implants in regions #34 and #44 and a single implant in the midline region #41 were planned. Since the implants were not splinted and the patient was a smoker, a conventional healing protocol of 8 weeks before loading was planned. The bone was softer in the maxilla, so a delayed protocol with the Straumann® Tissue Level implants was planned.
In the mandible, a full-thickness mucoperiosteal flap was raised, followed by extraction of all remaining teeth. Straumann® BLT 4.1 x 12 mm implants (SLActive®) were placed in the sockets of 44 and 34, while a Straumann® BLT 3.3 x 12 mm implant (SLActive®) was placed in the region 41. In the maxilla, all teeth had already been extracted and the sockets had fully healed. Suture removal and healing was uneventful (Figs. 2-3). In the meantime, a set of full dentures was delivered. Next, a full-thickness mucoperiosteal flap was raised in the maxilla, and 4.1 x 12 mm TL SP implants were placed in region #14 and #24. In the anterior region, 3.3 x 12 mm NNC implants were placed with a slight facial inclination due to the inclination of the residual bone. Subgingival healing was chosen since the prosthesis could generate pressure, leading to possible issues with osseointegration.
After 2 months healing time, the 3 mm straight Novaloc® abutments were attached, with a force of 35 Ncm, to the implants in the mandible (Figs. 4-5) and the matrices, and a pickup impression was taken. In the upper jaw, because of the facial inclination of the anterior implants, the 2 mm 15 degree angulated Novaloc® abutments (Fig. 6) were placed to align the insertion path of the prosthesis and to reduce the wear on the matrices (Figs. 7-9). The angulated abutment is a 2-piece abutment with removable screw. It is available in A and B versions for NNC and BLT implants due to the cross-fit connection. For TL implants it is only available in one version since the SynOcta® allows for 8 different abutment positions. A standard impression with pick up technique was taken again and sent to the lab for the design of the metal framework for the final removable prosthesis without palatal support. Both the smile set-up and the occlusion were corrected accordingly.
Sets of removable upper and lower dentures on 7 Novaloc® abutments were produced and mounted (Figs. 10-11). The patient was provided with a low-cost solution, ensuring a good level of comfort and easy access for cleaning (Figs. 12-13).
Straumann® BLT implants are safe for immediate insertion in extraction sockets. The Novaloc® abutments ensure good retention to the dentures, and the 15 degree angulated abutments allow for correction of the insertion path – which is especially helpful in the maxilla.
