Full arch implant treatment

Dr. Mark Willings and dental technician Steve Campbell describe how they worked in partnership to replace a patient’s “hated” denture

T his article describes one of the cases treated with the Astra Tech Implant System™ EV during its “ambassador program” — a pre-launch evaluation of what the manufacturer calls the “latest step in the system’s continuous evolution.” Dr. Mark Willings was invited onto the program for the final testing stages of development, having used the Astra Tech Implant System for about 15 years. He placed 20 EV implants during the trial.

[userloggedin]

Diagnosis

A female patient in her 60s was referred by her general dental practitioner, looking for a fixed replacement for her Valplast® partial upper denture, which she hated. Her last few remaining upper teeth were loose and failing. The initial diagnosis was denture intolerance and failing remaining natural teeth. The lower jaw also lacked posterior support, due to missing back teeth and chronic adult periodontitis.

The patient had already dismissed the option of conventional dentures as she was struggling with the partial upper denture she had. The reason she sought our opinion was for fixed rehabilitation, and thus, implant treatment was the only consideration for her.

The agreed treatment plan had five stages:

1. Maintaining the remaining upper teeth, while placing seven dental implants in the upper jaw
2. After integration, removal of all the remaining upper teeth, placement of abutments, and temporary acrylic bridgework
3. Provision of posterior support in the lower jaw with implant-borne bridges
4. Periodontal treatment to retain the remaining lower teeth
5. After healing and remodelling, fitting of definitive porcelain-bonded bridgework

Surgical phase

After completion of a diagnostic wax-up and CT scan, seven Astra Tech Implant System OsseoSpeed EV dental implants were placed in the upper jaw. Following initial soft tissue healing, a further four EV implants were placed in the lower jaw.

The implants were allowed to integrate for 8 weeks. Then fixture head impressions were taken in the lower jaw for custom abutments to be fabricated.

Temporary acrylic bridges were fitted for both LR4 to LR6 and LL4 to LL6. Once these were installed, the upper implants were exposed and fixture head impressions taken.

The laboratory selected uni-abutments and manufactured temporary acrylic bridgework. This was then fitted at the next clinical appointment. At the same time, the remaining upper teeth were extracted. The soft tissue was allowed to heal, and the bone was left to remodel for approximately 4 months. Pick-up impressions of the metal work in the lower jaw were taken to finalize the definitive porcelain-bonded bridgework. In the upper jaw, impressions were taken at abutment level and a mock-up made of the upper teeth.

Restoration

Once we were satisfied with the tooth shape, morphology, position, and occlusion, the metal framework was fabricated. This was then tried in to ensure a passive fit.

An Atlantis™ Isus metal framework was fabricated in milled cobalt chrome. Final bite registration was taken and recorded on the framework using pattern resin. This was returned to the laboratory for completion of the porcelain work. Finally, the bridge was secured into place.

As a whole, the results of the cases we treated during the trial were superb, with beautiful, esthetic restorations. In our opinion, the EV system gives great results across the board.

Laboratory work
The first stage of the laboratory work was to produce temporary bridges, according to pre-surgical bites and models. Then the cases were cast, and the multi-unit abutments needed to fabricate the bridgework were selected.

A verification jig was produced, and the tooth set-up was finalized from all the information gathered when the temporary bridges were fitted.

This ensured that an accurate impression was obtained, along with the confirmed final prosthetic envelope within which the final frameworks needed to be designed.

Manufacture

The case was esthetically challenging, as no pink ceramic was involved. The dimensions of the incisal length-to-width ratios, interdental shaping, and emergence profile needed careful consideration. The framework for the implant level bridge on the upper arch was produced using Atlantis Isus. The system provided the highest quality substructure for the ceramists to work on. This ensured a strong and passive foundation, which would serve the patient for many years to come (Mertens, et al., 2012).

The lower arch was not suitable for direct screw-retained fixings due to the access holes coming through in the esthetic zone. Instead, four Atlantis CAD/CAM abutments were made.

These were then milled and tapped in the laboratory to accept a metal framework that would be screw-retained onto the existing custom Atlantis abutments. This created a screw-retained bridge, but without the access holes coming through the buccal surfaces of the restoration. The final bridgework was produced by Jack Gleave of Ambridge Ceramics Ltd., North Yorkshire, England, using Creation ceramic.

In our opinion, the Astra Tech Implant System EV is easy to use and genuinely seems to have been developed from the crown down. The technician can trust the system components to provide accurate information to create the ideal crown.

Conclusion

The end result was excellent. Healing was uneventful, and the patient quickly recovered, following the surgical phase of the treatment. Aftercare involves meticulous attention and good oral hygiene with regular visits to the hygienist every 3 months (Yi, et al., 2001).

The patient is delighted with both function and esthetics. She is very pleased to be without a denture and is happy to have function restored. Also, she does not have to worry about a denture dropping or moving around. She can eat whatever she likes, smile with confidence, and has remarked: “I feel like I have my own teeth once again.”

References
1. Mertens C, Steveling HG, Stucke K, Petzl B, Meyer-Baumer A. Fixed implant-retained rehabilitation of the edentulous maxilla: 11-year results of a prospective study. Clin Implant Dent Relat Res. 2012;14(6): 816-827.
2. Yi SW, Ericsson I, Kim CK, Carlsson GE, Nilner K. Implant-supported fixed prostheses for the rehabilitation of periodontally compromised dentitions: a 3-year prospective clinical study. Clin Implant Dent Relat Res. 2001;3(3): 125-134.

[/userloggedin]
[userloggedout][/userloggedout]