September 2012, Volume 8, Issue 9
Published by AEGIS Communications
Placing a Predictable Long-Span Bridge
The best results depend on cooperation between the patient and the professionals.
In the case presented in this article, the patient complained of upper and lower dentures that were fairly new but did not fit properly. Not only were they loose, they did not look attractive and were not suitable for eating. She was extremely disappointed that a 2-month-old set of dentures provided her with such an unappealing solution, and she desired a more permanent treatment plan.
The attending clinician performed an examination and found edentulous ridges, impactions on teeth Nos. 17 and 32, and heavy dense bone on the lower arch and firm dense bone in the upper-arch anterior region. The upper right and left sinuses had expanded to almost touch the ridge from the second bicuspids to the second molars. All ridges exhibited minor to moderate bone loss in width on the lower ridge. The patient was Class III; her teeth were flared to nearly an edge-to-edge setting.
The treatment plan recommendations included a new full upper and lower denture to act as a provisional restoration. An implant-supported overdenture, hybrid denture, or fixed bridgework were the patient’s final treatment options; she chose the fixed bridgework as the option that was best for her.
After the delivery of the new dentures, the patient still desired a more fixed restoration. Any type of material on her palate instigated a pharyngeal reflex, which she wanted to avoid. A primary alginate set of impressions was taken, and a computed tomography image scan (i-CAT®, Imaging Sciences Intl, www..imagingsciences.com) was performed to determine implant placement. Tissue stents were used to help facilitate implant placement by the periodontist. It was determined that placement would involve four Biomet 3i™ implants (Biomet 3i Implant Systems, www..biomet3i.com/">www..biomet3i.com) on the upper arch and six on the lower arch. The fixed hybrid was placed on the lower arch. A custom-tray pick-up impression was taken with open-tray impression copings, and the framework was tried in with teeth set in wax twice and finished in acrylic. The denture was screwed down to the implants and the access openings were covered in Fermit™ (Pearson Dental, www..pearson
The clinician helped the laboratory facilitate a tightly scheduled patient case with communication using a variety of tools: telephone, e-mail, and photographs sent via e-mail. All of these methods of conveying the desired outcome enhanced the process for the doctor, patient, and laboratory tremendously. Timing was difficult because the patient was undergoing cancer treatment in the hospital while awaiting her final prosthesis. This led to many delayed appointments and complications in treatment.
The technician was able to determine the size of the teeth by imagining what her dentition should resemble in comparison to the lip line and the midline (Figure 1). Contour, shape, and length were also considered during this evaluation. In the clinical setting, the dentist placed the healing caps over the abutments (Figure 2) after the implants were placed. The 4-unit titanium abutments were fabricated by GC Advanced Technologies Milling Center (www..gc-at.com) (Figure 3).
For verification of implant placement, a verification index was used (Figure 4); the implant-supported bridge was fabricated using Primopattern LC Gel from Primotec (www..primotecusa.com). In the 10-unit wax design, the technician recognized a need for a solid and consistent fit (Figure 5), and therefore used a wide sprue for better support throughout. He then arranged and light-cured the wax, which had been positioned according to the previously determined design pattern.
The 10-unit titanium bridge was then checked on the model for fit (Figure 6), and a carbide bur was used to finish the metal work after casting. During the opaque stage, the bridge was tried on the model (Figure 7), and was checked with index putty using the temporary denture created with the duplicate model. This fit check on the model helped determined the final length and size of the teeth. The bridge was next tried on the patient’s model with a wax-and-frame design after the opaque had been applied (Figure 8). There were several aspects of the bridge that were being checked: overall fit, incisal-edge position, facial thickness, and anatomy.
For best life-like and esthetic results, the technician prefers to use GC Initial™ Porcelain (GC America Inc., www.gcamerica.com) (Figure 9). After the second bake, he applied the dentin layer for height of contour and shape of the incisal corner (Figure 10). GC America offers a variety of gum-colored porcelain, which can be mixed and matched to create life-like results that match the patient’s natural tissue color (Figure 11). In finishing the contouring process, the technician applied the appropriate tissue color to the gingival area of the prosthesis (Figure 12). On a mirrored surface, he displayed the restoration with appropriate markings for surface texture (Figure 13). In the glazing stage, many characteristics were applied to achieve a warm tone for the final restoration (Figure 14).
In the immediate image after it was tried in the mouth (Figure 15), the patient was retracted for a complete fit and appearance check. A side view shows the esthetic appearance of the prosthesis (Figure 16). A radiograph verifies implant and restoration placement (Figure 17). The final smile view perfectly captures her happiness with the new denture (Figure 18).
Predictability is important in an edentulous case. A cement-retained long-span bridge such as this one made it difficult to create a good frame design, and it is proper frame design that leads to better color and esthetics, from the laboratory’s viewpoint.
Without proper communication between the clinician, patient, and laboratory, these results cannot be accomplished. The continuous scheduling of the necessary steps for the patient’s finest outcome became difficult to achieve because the patient was not in the best of health. However, with everyone working together, laying the groundwork for the case from the beginning, an excellent ending was produced. Using skill and knowledge, dental professionals can and should work with the patient to bring about this type of result.
To read another article about Laboratory Communication, visit: dentalaegis.com/go/id328
About the Authors
William Cohen, DDS, AACD
Luke S. Kahng, CDT
LSK121 Oral Prosthetics