#Edentulous 22. Jun 2020

A clinical case report on maxillary compromised dentition treated with Straumann® Pro Arch and Digital Workflow

A clinical case report by Tran Thanh Phong, Saigon/Vietnam

This case describes how a full arch rehabilitation with computerized digital planning (coDiagnostiX) and Straumann® Guided Surgery, treated with immediate implant placement and immediate screw-retained CAD/CAM provisionalization leaded to an outstanding treatment outcome.

Successful immediate implant placement associated with immediate loading remains one of the biggest clinical challenges. In addition to the placement of an implant immediately into the socket, the creation of an immediate screw-retained CAD/CAM provisional restoration is critical for an optimal esthetic outcome. When using a conventional approach, the procedures require an extensive number of patient appointments and chair-time for the dentist and the patient. Fortunately, nowadays digital workflows can be implemented in our practice and with this, our treatments could be considerably shortened.

In the following case report, a digital workflow allowed us to have an efficient and predictable treatment protocol for the immediate implant placement and the prosthetic restoration design, including the individual emergence profiles prior to the surgery. This also led to an excellent patient experience and satisfaction. The goal of this clinical report is therefore, to introduce an innovative one-step surgical approach for immediate screw-retained CAD/CAM provisionalization by using the latest technological improvements in prosthetic and surgical planning software and seamlessly integrating the dental technician into the development of the digital treatment planning and new prosthetics options.

Initial Situation

A 51-year-old male patient, smoker (<10 cigarettes per day), with a good general health condition; presented in the clinic with missing molars in quadrats 2 and 4, class 3 mobility on the teeth #24, #17 and decayed roots and gum inflammation, without abscess nor sinusitis on #16. The anterior zone showed different levels of recession, bone resorption and deep periodontal pockets on tooth #12 and #22 which let the patient complain about an esthetically unsatisfying restoration. (Fig. 1-2).

Treatment planning

Following the clinical and radiographic assessments, the patient was introduced to two different treatment options. The first one included the maintenance of the canines by treating their recession and bone resorption which has exposed more than half of the roots, implant placement on the incisors region with soft tissue grafting, and extractions of the remaining posterior teeth and implant treatment after GBR and sinus lifting. Moreover, in this option, the final restoration carried an implant – supported bridge on the region of #14-#16, #12-#22, #24-#26 and crowns on #13 and #23 after three months.

The second treatment option consisted on extraction of all the remining teeth of maxilla and restauration of the full arch with the Pro Arch concept. This consisted in the placement of four Straumann® BLX implant immediately after extraction on the region of teeth #15, # 12, #22, #25 with a fully digitalized approach, using guided surgery and preoperative prosthetic screw retained CAD/CAM restauration which is in function and esthetic right after surgery and a final restauration placed in six to twelve months later.

The total treatment of the first option resulted in 1 year and 8 months, resulting in a higher number of visits, longer chair-time and higher costs in comparison to the second option.

The reliable and short treatment protocol and unavailability of our patient to visit the clinic for a considerably long period of time, made patient choose the second option.

Note: patient will receive a holistic treatment approach for the lower dentition. However, the current Covid19 situation has forced us to delay the treatment.

Implant placement planning

The STL file was taken to record the patient’s current oral situation and DSD file, the future prosthetic design was created with software for lab (Fig.3-6). The three-dimensional radiographic DICOM data and the prosthetic design project STL file were matched in coDiagnostiX™(Fig.7-9) The pin fixation guide, bone reduction guide, surgical guide and bite registration guide was designed with coDiagnostiX™ (Fig.10-13) and produced using three-dimensional printing technology.

Prosthetic design planning

To design the prosthetic digitally firstly we selected the screw retained abutment (SRA) angle and gingival height (Fig. 14) then we created the patient model on which we could connect the BLX Implant with SRA abutment selected from Straumann library (Fig. 15). The implant placement guide was on the model leveraging the high stability that we could gain from palatal support (Fig.16-17). After printing the model, the BLX implant analogues were positioned using the template for navigation. The digital planning using coDiagnostiX (Version 9.14) allowed the dental technician to identify all the necessary parameters related to implant position (Fig.18-22). Emergence profiles were set-up on the model (Fig. 23). The model was scanned using the scanned bodies and a CAD/CAM temporary restoration was designed and milled (PMMA-based restoration ¬material) (Fig. 24-29).

Guided surgery

On the day of surgery, we prepared the surgical protocol provided by the implant planning software, which guided us on the drilling sequence and the use of the appropriate instruments for the implant bed preparation (Fig. 30a- 30b). After the fixation pins were allocated, the teeth # 17, #16, #15, #13, #12, #22, #23 and #24 were atraumatic extracted and followed by alveolectomy, using a bone reduction guide (Fig. 31-36). Four implants (Straumann® BLX ø 4.5 mm RB SLActive® 12mm Roxolid®) were placed, two straights in the anterior zone and two titled implants in the posterior zone. All implants were stabilized with a torque of 50 N/cm (Fig.37-43) and the SRAs were placed on top, with an angulation of 30º on the posterior implants (angled 30°, ø4.6 mm, GH 3,5) and 17º on the anterior implant (angled 17°, ø4.6 mm, GH 3,5) (Fig. 44-45).

The bite registration guide was fixed with pins and the open tray impression copings were placed on the SRAs of the anterior implants, which were fixed with the guide using flowable composite and then sent to the lab (Fig. 46-50). Afterwards, we checked the temporary CAD/CAM bridge which was designed before surgery (Fig. 51) and finally, protective caps were placed on the SRAs followed by bone grafting using Cerabone® Granulate with a 1-2mm grain size, on the extraction socket and suture (Fig. 52- 54).

Impression taking for temporary Zirconia bridge

Due to circumstances patient was not able to visit the clinic periodically for follow-ups, therefore we decided to use an immediate PMMA bridge for a short time, and design an immediate temporary bridge on Zirconia material to optimize the condition and patient experience while he was not able to visit our clinic.

For the impressions, we used open tray impression copings (Fig. 55), and together with the bite registration were transferred to the lab (Fig. 56-57). The PMMA bridge was screwed on the SRAs and the DSD file was taken (Fig. 58).

Lab procedures for temporary Zirconia bridge

After creating the master cast, we were able to scan and design the Zirconia prosthesis (Fig.59-62). The design of the Zirconia frame was done by obtaining the information form the bite registration, the image of the of the temporary prosthetic design (Fig. 6) and the mock copied by DSD with temporary PMMA bridge (Fig. 58); at this moment we could apply a few modification to the zirconia frame . The design of the temporary zirconia bridge was sent to the milling unit and produced on a full contour zirconia disc. The zirconia frame was then cemented on Variobase coping as an interface to be screwed on SRA abutment (Fig.63-64).

Five days follow up

After five days, patient returned to the clinic, the fixed PMMA temporary bridge was removed and the temporary CAD-CAM zirconia bridge was placed allowing a passive fit on the abutments, with an initial hand tightening of each SRA screw up to 5 Ncm. After the seating was checked, the torque of each SRA screw was increased up to 35 Ncm, and the bridge was screwed in at a torque of 15 Ncm. Occlusion was checked and contacts were inspected. Screw holes were sealed with PTFE and a temporary filling material (Fig. 65). A panoramic X-ray was recorded, and SRA screw positions were evaluated to confirm the perfect temporary bridge fit (Fig. 66). Oral hygiene and diet instructions were given to the patient, and a one-week follow-up appointment was scheduled.

Treatment outcomes

Immediate implant placement associated with immediate loading is a predictable protocol with some variables. The digital tooth extraction was integrated with the production of a screw-retained CAD/CAM provisional restoration prior to the surgery and was successfully achieved. The entire treatment workflow was done fully digitally. Only a single surgical step was required to provide an entire individualized prosthetic rehabilitation.