Full Chairside Extraoral Conversion Using Straumann Pro Arch

Today, we are promoting full-arch prostheses with similar designs as in the 1980s using CAD/CAM. As well, many of these patients present dentate or partially dentate, requiring many extractions the day of implant placement. Dental implant manufacturers have embraced the protocols with new marketing campaigns that introduced us to terms such as All-on-4® (Nobel Biocare, nobelbiocare.com), DIEM® (Biomet 3i, biomet3i.com), Pro Arch (Straumann®, straumann.us), RevitaliZe™ (Zimmer Dental, zimmerdental.com), and SmartFix™ (Ankylos®/Dentsply Implants, dentsplyimplants.com). These names are used by each manufacturer to identify fixed immediate full-arch solutions to dental professionals.

Today, many dental teams in the US employ a dental technician chairside during parts of the immediate load process. Restorative dentists are certainly qualified to deliver this service to patients, but having a technician chairside allows the dentist the opportunity to tap into another team member’s knowledge base. This collaboration also allows the dentist(s) to focus on what they do best: clinical treatment.

Many dental laboratories are offering chairside services to their dentist-clients. This may be limited to input on abutment selection, impressioning, and bite registration followed by next-day prosthesis delivery, to full chairside support including same-day in-office prosthesis fabrication.

The following case employs full chairside extraoral conversion. The actual denture prosthesis will not be placed intraorally until after its conversion to a fixed temporary prosthesis.

This case was delivered utilizing the Straumann Pro Arch solution.

Straumann Pro Arch builds its restorative platform on transmucosal abutments. The screw-retained abutments have a standardized restorative interface for both the NC and RC Bone Level Implants, and are available in 0˚, 17˚, and 30˚ abutments with a variety of gingival heights. The prosthetic components utilize one universal impression coping, occlusal screw, and analog. The restorative interface of these abutments has a 22˚ taper from the path of insertion. This allows up to a 43˚ path of draw from the abutments while maintaining a passive fit of the restoration to abutments around the arch. This 22˚ angle, plus the 17˚ or 30˚ re-angulation to the implant path, allows for implant placement in native bone without grafting procedures in most cases.

Immediate loading of endosseous implants requires primary stability of the implant to be at generally accepted torque values of 30-35 Ncm or higher. This allows the surgeon to follow the available bone topography and correct for the angles prosthetically. The screw-retained abutments raise the restorative platform, allowing the clinician to perform the procedures less invasively away from the implant bone interface. The straight screw-retained abutments are available in 1-, 2.5-, and 4-mm gingival heights, and the angled screw-retained abutments are available in 2.5- and 4-mm gingival heights.

The preliminary records required to deliver this procedure include accurate maxillary and mandibular casts that feature all anatomic landmarks, bite records, photographic documentation, and a CT scan if indicated by the surgeon.

Additionally, prosthetic observations need to be made regarding future tooth position. Most of the teeth in these severely debilitated dentitions are in malalignment to their correct and future tooth prosthetic positions. The dental technician needs to fabricate an immediate denture as part of this treatment.

When fabricating the immediate denture, the technician must take tooth position corrections such as overbite, overjet, and irregularities in the occlusal plane into consideration.

The patient presented with a failing mandibular dentition and a maxillary complete denture (Figure 1 and Figure 2). Temporary tattoos were placed on the patient’s nose and chin, and a centric occlusion measurement was recorded (Figure 3). Prior to placing the Straumann® Bone Level Tapered Implants (Figure 4), the dental laboratory fabricated a complete mandibular denture, a bone reduction template, and a clear conventional surgical template (Figure 5). The mandibular teeth were extracted and bone reduction was completed. The reduction of the residual ridge is critical. Without adequate inter-arch space, creating a prosthesis that will withstand the forces of mastication becomes more difficult. Eight mm of reduction below the CEJ of the proposed restorative teeth is ideal.

Straumann Bone Level Tapered Implants were placed using conventional protocols. All of the implants were torqued to a minimum of 35 Ncm.

Utilizing the conventional surgical guide, the abutments that the authors selected and used to re-angulate the restorative access channels in a more ideal prosthetic position were used to bring the restorative platform to the soft tissue crest (Figure 6). The abutments were then torqued to 35 Ncm. Prior to suturing, the Straumann Titanium copings were secured and a piece of rubber dam was trimmed to fit the mandibular ridge over the copings. They were filled with a light-bodied PVS to maintain the patency of the access channels to the occlusal screws. The clear template was then adjusted to fit over the titanium copings and secured to them (Figure 7) with a dual cure composite resin (Triad® DuaLine®, DENTSPLY, dentsply.com). The vertical dimension of occlusion was measured and a centric relation bite was taken on the template in vivo. The template was then removed from the mouth and suturing was completed simultaneously with the laboratory procedures.

It is essential to the success of this procedure that the laboratory come prepared with backup materials even if the surgeon has ordered components prior to surgery. This ensures preparation for any contingencies and that expectations are met for both the surgeon and the patient (Figure 8).

Screw-retained abutment analogs were secured to the titanium copings and a master cast was poured and mounted. The prosthesis was then created by securing the denture to a second set of titanium cylinders (Figure 9). After finishing and polishing, the temporary prosthesis was delivered to the patient and torqued to 15 Ncm. Centric occlusion was adjusted and the patient was dismissed with homecare and instructions to maintain a soft diet for six weeks (Figure 10). This treatment protocol allows the treatment sequence to be minimized, and maintains the patient in a fixed dentition throughout their treatment.

Acknowledgement

Surgical work for this case was performed by Thomas Sterio, DMD, MS, of Perico Dental.

Ira Dickerman, CDT, TE, is the President of Dickerman Dental Prosthetics in Sharon, Massachusetts. Brandon Dickerman, BA, specializes in digital dentistry with an emphasis on guided surgery and 3D treatment planning.

Disclaimer: The statements and opinions contained in the preceding material are not of the editors, publisher, or the Editorial Board of Inside Dental Technology.

For more information, contact:
Straumann
straumannproarch.com
800-448-8168