Sequential Extraction Protocol for Full Arch Implant Therapy

Given the pros and cons outlined here, I hope it will be evident that the Sequential Extraction Protocol deserves thoughtful consideration in full arch implant cases. Transitioning patients with extremely debilitated dentitions (also called “terminal dentition”) to a fixed implant supported reconstruction has become a common treatment modality which can be carried out using different techniques and protocols. In this article, I will examine the pros and cons of the various modalities, with a special focus on sequential extraction protocol and why it is often a favorable alternative.

Depending on the clinical condition, the patient's willingness to adhere to the clinical team’s home care instructions and behavioral recommendations (such as staying away from hard foods and parafunctional habits), and the operator’s experience, the treating team may choose from the following provisionalization options:

 

Removable Denture Provisional Restoration

Choosing a removable complete denture during the provisionalization stage presents clear advantages and shortcomings.

Advantages:

• For those patients with advanced periodontal disease and active infection, removing teeth and letting both hard and soft tissue heal underneath a removable appliance provides a healthy intraoral environment which can later be optimally conducive to implant therapy.

Shortcomings:

• There is an undeniable psychological impact on patients that undergo this transitional process.
• Remodeling of the soft tissues, which leads to needing pink ceramics to compensate for such deficiency.
• In those instances where hard and soft tissue deficiencies require a graft, the continual pressure of a removable appliance in the area may be deleterious to the grafted area.

 

Mini-Implant-Retained Provisional Restoration

Using mini-implants, or transitional implants, allows patients to avoid having to use a removable appliance and protects the submerged implants and potentially grafted areas from being actively loaded. Those are the pros. The cons here are largely the added cost and additional time involved.

 

Immediate Loading Protocol

Few topics have been extensively covered in dental literature such as the concept of immediate loading protocols showing extremely high survival rates with full arch fixed solutions.

Their main advantages include:

• Single surgical intervention
• Reduced treatment time
• Great psychological impact
• Marketing potential

Nonetheless a thorough risk assessment needs to be conducted to see if patients meet the desired criteria prior to embarking on this protocol. This risk assessment is summarized in the following table:

Now we get to the method I want to highlight. For those patients where the success of an immediate loading does not seem to be indicated, the concept of sequential extraction (also called the “staged extraction approach), has been extensively proven to be a fantastic alternative.

The idea behind this treatment modality is to temporarily rely on a few hopeless yet strategic teeth (normally structurally debilitated) as abutments so they can provide support for a full arch-fixed provisional restoration during the osseointegration phase of the implants/grafts. Therefore, the number and distribution—and a minimally acceptable degree of structural integrity—of these hopeless teeth become important to ensure success.

A preliminary appointment is needed to remove the defective restorations and a provisional restoration is fabricated in order to stabilize the patient both esthetically and functionally. This allows the treating team to create a preliminary blueprint of the contours of the definitive restoration.

Once this has been established and validated by the patient, it then becomes important to decide on the preferred implant sites. A surgical template is then fabricated. For these cases, a common approach is to reline a duplicate of the provisional restoration clear acrylic shell. An often-used technique is to do a pickup alginate impression of the relined shell and then pour in order to obtain a working cast from which the perforations for the desired implant sited can be done in the laboratory. (It should be noted that this may also be conducted using a digital workflow where a 3D printed guide can be produced.)

A 4-dimensional (mesio-distal, buccal-lingual, apical-coronal and angulation) restrictive surgical template is generated allowing the surgeon to place the implants in the ideal locations.

Once the implants are placed in their ideal location, either cover screws or healing abutments are then secured, and the provisional restoration is temporarily cemented, allowing a window of 8 to 12 weeks for the submerged implants to integrate.

Once time has been allotted for osseointegration, the patient is scanned for the fabrication of a PMMA milled prototype provisional restoration. The appointment consists of four scans: with provisional, without provisional and with the scan bodies secured to the implants, as well as a scan of the opposing arch, and lastly a scan of the intermaxillary record.

Once the provisional is produced, the patient is appointed for the extractions of the remaining abutment teeth and the provisional restoration is then secured into place. Ovate pontics have been previously designed, which will guide the soft tissue maturation to a natural-looking optimal configuration.

Once time is allotted for soft tissue maturation, a final impression is made for the fabrication of the definitive prosthesis.

 

An Extraordinary Alternative

A sequential extraction protocol can be an extraordinary alternative when transitioning patients with a severely debilitated dentition to a fixed-implant supported reconstruction, particularly when the rationale for removing the remaining teeth is their lack of long-term structural integrity required to predicably withstand a tooth-supported reconstruction. This means that a few strategically distributed teeth will temporarily be responsible for providing support of the provisional restorations while the implants are installed and submerged during the osseointegration phase.

The treating team needs to be aware that there are a few disadvantages of using a sequential extraction protocol which will influence treatment, such as:

• Prolonged treatment time
• If the residual teeth are extremely debilitated, the need to see the patient periodically to ensure the provisional is stable.
• It can often mean that eventually a second set of prototype provisional restorations will be needed.

Given the pros and cons outlined here, I hope it will be evident that the Sequential Extraction Protocol deserves thoughtful consideration in full arch implant cases.

Ricardo Mitrani, D.D.S., M.S.D., is a member of Spear Resident Faculty.

 

References:

1. Schnitman, P. A., Wohrle, P. S., Rubenstein, J. E., DaSilva, J. D., & Wang, N. H. (1997). Ten-year results for Branemark implants immediately loaded with fixed prostheses at implant placement. International Journal of Oral & Maxillofacial Implants, 12(4).
2. Grunder, U. (2001). Immediate functional loading of immediate implants in edentulous arches: two-year results. International Journal of Periodontics & Restorative Dentistry, 21(6).
3. Waliszewski, M., & Janakievski, J. (2005). Sequencing patients to implant-supported, full-mouth reconstructions: a case report. Practical Procedures & Aesthetic Dentistry: PPAD, 17(4), 267-72.
4. Mijiritsky, E., Mazor, Z., Lorean, A., Mortellaro, C., Mardinger, O., & Levin, L. (2014). Transition From Hopeless Dentition to Full-Arch Fixed-Implant–Supported Rehabilitation by a Staged Extraction Approach: Rationale and Technique. Journal of Craniofacial Surgery, 25(3), 847-850.