Alfonso Rao, Clinical Director at Queen Square Dental and Implant Clinic presents a clinical case study using Straumann® Pro Arch.
A 71-year-old male patient – an ex-smoker with high blood pressure and cholesterol controlled with medications – required fixed rehabilitation in his upper and lower jaw to replace failing existing bridges that had been given to him three years previously.
The patient presented with signs of periodontal disease and both acute and chronic infections.
Several teeth were mobile, there were repeated abscesses and the patient was unsatisfied with the aesthetics of his existing bridge. He had removable prostheses in the past but was unable to tolerate them and was therefore seeking a fixed solution.
After a complete history and clinical examination, diagnostic alginate impressions and photographs were obtained. Clinical and radiographic findings confirmed the diagnosis of periodontal disease, failing bridges with poor prognosis and impacted canine UR3.
Extraction of hopeless teeth and temporisation with acrylic dentures was agreed. The lower left canine was left in situ to improve the stabilisation of his lower temporary denture.
His diagnostic study casts were mounted on a SAM-3 articulator with a facebow transfer and evaluated for skeletal relationship, basal alveolar bone, and potential ideal tooth position. Extractions were performed under IV sedation.
After 12 weeks, healing was reviewed and his temporary acrylic dentures adjusted to evaluate teeth position, lip support, phonetic and desired aesthetic outcomes.
At this stage, the patient confirmed his wish to continue with the original treatment plan as he was unable to tolerate a removable prosthesis. A cone beam CT scan was obtained to evaluate bone quantity and quality and for identification of available bone volume for implant placement to maximise implant distribution and avoid vital structures including maxillary sinuses and the nasal floor. His temporary dentures were used with radiopaque resin as a stent. A surgical stent was made by copying in clear acrylic his existing denture.
The scan was sent to a radiologist for a report.
Informed consent was obtained for placement of five implants on the upper jaw and six implants on the mandibular, extraction of impacted canine and simultaneous bone augmentation with a mix of autogenous and xenograft bone under local anaesthetic with conscious sedation. In addition, the goal of treatment that day included fabrication of immediate load fixed provisional bridges.
The patient’s son escorted him to our practice on the day of the surgery. The patient’s vital signs were monitored throughout the procedure. After reflection of a mucoperiosteal flap, the impacted upper canine and the lower left canine were removed.
Implant osteotomy sites were initiated. These distal implant sites were tilted to avoid the anterior wall of the maxillary sinuses and to maximise the amount of anterior-posterior implant distribution. Implant site preparation and final placement was confirmed with the assistance of a clear surgical template.
A total of 11 Straumann® Bone Level Tapered Regular Crossfit SLActive® Roxolid® implants were placed in the maxilla and mandible with an insertion torque between 35-50 Ncm.
In order to achieve the placement of screw access holes in ideal prosthetic positions for the prosthesis, two 17° angled abutments were placed on the maxilla for the lower jaw, and for the three remaining on the upper, straight screw-retained abutments (SRAs) were placed using 35 Ncm of torque on the abutment screws.
Autogenous bone was harvested from the maxillary tuberosity and nasal spine with a bone scraper, mixed with Straumann Cerabone® and Endoret®(prgf®), and placed to fill the bone defects where the impacted canine was removed, and here large bone defects were present.
The flap was closed with a 4.0 PGA (Omnia) and interrupted sutures. Upper and lower complete dentures were then inserted over the abutments and protective caps to transfer the position of screw access hole locations to the prosthesis.
Upper and lower impressions were taken with special trays and Polyvinylsiloxane material.
Titanium copings for the SRA abutments were attached at 15 Ncm to confirm proper modification of the denture. Teflon tape was placed into the titanium copings.
A dual polymerising resin (Q-resin) was placed in the dentures and injected around the copings to firmly index and attach the titanium copings within the denture. Both prostheses were disinfected and taken into the in-house laboratory for conversion into a fixed provisional bridge.
The converted prosthesis hybrids were delivered on the abutments with prosthetic screws at 15 Ncm.
Post-operative written instructions and medications were reviewed with the patient and his son. They were reminded that the patient must adhere to an extremely soft diet for the first six weeks following the procedure.
The patient was seen for a series of follow-up appointments to evaluate healing over the first two months. After four months of uneventful healing, the patient was brought back to begin fabrication of the final prostheses.
The fabrication of the final hybrid restorations usually requires a series of five one-hour appointments, which usually do not require the administration of local anaesthetic. The screw access hole fillings were removed and the provisional bridge was removed. All abutment screws were checked to confirm and tighten at 35 Ncm.
Open tray SRA impression copings were placed over the abutments and final full arch impressions were made with a Polyvinylsiloxane material and a DuraLay Jig. Master casts were poured using SRA analogues and Softissue Moulage™ material. The casts were then verified with a lab-made verification jig and mounted using the patient’s provisional hybrids during the second clinical appointment.
A tooth set up on wax rims was tried in to verify aesthetics and phonetics at the third clinical appointment to confirm tooth position. The technician designed the CAD/CAM titanium bar to precisely fit the implant abutments and support the final denture teeth in the permanent prostheses. The Createch titanium bars were tried in to verify passive fit on the implant abutments prior to final processing. The bridge was then returned to the lab for opaquing of the bars, final flasking and processing with an injection-moulded acrylic resin on the lower, and porcelain on the upper. The final bridges were delivered to the patient and occlusion was again checked and adjusted. An ortho-panoramic of the completed treatment verified ideal implant healing and fit of the final CAD/CAM titanium bars.
The patient’s post-operative clinical result revealed a patient who was extremely pleased with the process and the definitive outcome.
The Straumann® Pro Arch protocol using screw-retained abutments was particularly well-suited for this patient’s challenge. Although it was possible to follow an immediate loading protocol, it was necessary to treat this case with a two-stage approach. It’s essential to control and treat any pathology before embarking on any further treatment and the step of extractions and temporary dentures was compulsory to achieve a long-term success even if often patients don’t like this stage of their treatment.
The benefits of this treatment include improved masticatory function and appearance immediately following surgery, no sinus bone augmentation, reduced treatment time, and reduced cost.
I would like to thank Nick Tyler of Tyler Crown and Bridge for his exceptional work and support with this case (www.tylercrownandbridge.com) and Arpad Keresi of ACE dental studio (www.acedentalstudio.co.uk).
We will running a Pro Arch course in 2018 – to register your interest please call the Straumann Education Department on +44 (0)1293 651230.
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