Achieving Anterior Aesthetics in a Full-Arch Implant Case

INTRODUCTION
Implant-supported prostheses have proven to be a viable and predictable solution for patients with deteriorating dentition who seek a more natural solution with regards to function, biomechanics, and aesthetics. Advances in surgical and prosthetic components, implant designs, surface technology, and imaging techniques now allow for accelerated treatment times and reduced costs that benefit the patient. However, the merging of aesthetics and large implant cases has been slow to develop.

The Importance of Smile-Design Principles
Adhering to smile-design principles is essential when initiating any multiunit restoration, especially in the maxillary anterior region.^1,2 The foundation of any dental treatment, whether tooth-supported or implant-supported, is proper treatment planning. First the dentist needs to fully understand the patient’s aesthetic objectives and concerns. Then the clinician must evaluate the position of the incisal edges, occlusal plane, midline position, length and width of teeth, tissue height, lip fullness, occlusion, desired color, axial inclination, embrasure form, line angles, and surface texture.^1,2 Finally, in order to achieve an optimal aesthetic outcome, the dentist must provide the dental laboratory technician with a plan specifically designed for the patient being treated.³ The diagnostic tools involved in this process are photographs, radiographs, charts, periodontal probes, models, wax-ups, and diagnostic provisional restorations. Aesthetic treatment planning for the natural dentition can be a detailed process. However, this process becomes even more challenging in full-arch implant cases because the occlusion, tissue form, and teeth positions can all change.

Available Restorative Options
When planning a fixed solution for the edentulous maxilla, a number of options are available, such as cement-retained restorations on abutments, screw-retained restorations, a screw-retained framework with cemented crowns, and a screw-retained hybrid bridge with acrylic and denture teeth.^4,5 Each option offers distinct advantages and disadvantages. Selecting the proper restorative option involves many factors, including the vertical dimension; amount of missing bone; smile-line; number, position and distribution of implants; patient’s oral hygiene; and cost.^6,7

The option of cement-retained restorations on abutments is especially suited to patients with mild alveolar ridge resorption in whom the prosthesis will not need to provide lip support.⁸

CASE REPORT
Diagnosis and Treatment Planning
A 53-year-old male presented with pain and aesthetic concerns (Figure 1). He was aware that his posterior maxillary teeth were nonrestorable. In addition, his anterior teeth had failing root canals, posts, and crowns. After reviewing his options, the patient decided that the best option offered to him involved extracting his remaining teeth, the placement of implants, and the delivery of an appropriate dental prosthesis.

Figure 1. Preoperative photo showing the nonrestorable maxillary dentition.	Figure 2. Defective restorations were removed and 4 teeth prepared to hold the provisional restoration.

Figure 3. Teeth were extracted and bone grafts completed.

After consulting with an oral surgeon, it was decided to place 6 implants to support a full-arch restoration. Due to the number of immediate implants and amount of bone grafting, the oral surgeon felt that immediate loading would not be a good idea. However, the patient was concerned about wearing a removable prosthesis during the treatment process. The patient’s goal for his teeth was to have a younger, natural-looking and aesthetically appealing smile, in addition to being able to chew normally.

Photographs and models of similar cases were reviewed with the patient to inform him of the steps and the desired outcome of the restorative phase. However, such items have limited benefit, as patients often have difficulty visualizing their final results. This is an important challenge since, to achieve the best results, the patient, dentist, and laboratory technician must all be able to visualize the final outcome prior to fabricating the restorations.⁹ In a case like this, where there is minimal information to use for an aesthetic evaluation, it is critical to have a shared vision from the beginning.^1,2
To meet the patient’s request for a fixed provisional restoration throughout the treatment, 4 teeth—the first molars and lateral incisors—were to be kept during the implant-healing phase. These teeth all had a poor long-term prognosis, but would be maintained as support for a temporary, fixed partial denture.

Clinical Protocol

After the patient was anesthetized, the first molars and lateral incisors were prepared for bridge abutments (Figure 2). A full-arch vinyl polysiloxane (VPS) impression (Take 1 Advanced [Kerr]) was taken and sent to the dental laboratory team with an opposing impression, VPS bite registration (Flexitime Bite [Heraeus Kulzer]), face-bow, and photographs. 

The laboratory technician removed all of the other teeth (in dental stone) and approximated the tissue-healing positions. A full-arch acrylic bridge with metal support was fabricated. The patient then went to an oral surgeon who extracted all his teeth except for his first molars and canines. Bone grafts were done, as indicated (Figure 3). The provisional bridge was placed with provisional cement (TempBond clear [Kerr]) (Figure 4).

After a healing period of 3 months, the provisional bridge was removed, and the patient returned to the oral surgeon to have 6 maxillary implants (NobelSpeedy [Nobel Biocare]) placed at the premolar and central incisor sites. The same provisional bridge was placed on the 4 remaining teeth. Six months were allowed for complete healing of the implants. At this point, the bridge was removed and the patient again returned to the oral surgeon to have his 4 remaining teeth extracted and implants uncovered (Figure 5). The provisional bridge was converted from being tooth-supported to implant-supported.⁹ To do this, 3 holes were drilled into the provisional bridge at the site of the implants. Peak-cylinder temporary abutments were placed on the implants and then connected to the fully seated bridge using acrylic. For the 3 other implants, stock abutments were placed and the access holes filled with cotton. The provisional bridge was hollowed out in those areas and then relined to fit over the abutments. This combination of abutments was done to ensure that the provisional would not become locked into place while having a secure fit (Figure 6). Another 6 weeks of healing was allowed for complete healing prior to starting the process of final restoration.

Although the provisional restoration served as a guide for occlusion, aesthetics, vertical dimension of occlusion (VDO), and phonetics, a wax-up of the end result still was needed to guarantee a shared vision of the final results. To be able to create the diagnostic wax-up, the healing abutments were removed, impression posts inserted, and closed-tray VPS impressions taken. A stone model with simulated soft tissue was created by the laboratory technician. Next, screw-retained base plates with wax rims were fabricated to improve the accuracy of centric and other records. The wax rim was connected using nonengaging abutments to 3 of the implants (posterior right, posterior left, and anterior) to give it stability and make sure it was in the same position in the patient’s mouth as on the model.¹⁰ The wax rim was adjusted and marked to give the correct VDO, buccal-lingual position of the teeth, and incisal edge position. A face-bow was taken using the wax rim as the reference point for the maxillary teeth. The laboratory technician then used the wax rim and face-bow to properly mount the models on an articulator.

Figure 5. Once implants were uncovered, the remaining teeth were extracted.	Figure 6. The provisional bridge was connected to implants using temporary peak cylinders and stock abutments.
Figure 7. A full-arch wax-up was created by the laboratory technician.	Figure 8. The wax-up was tried-in the mouth to evaluate aesthetics, occlusion, and phonetics.
Figure 9. Abutments were placed using a seating jig.	Figure 10. The seating abutments in place.

Once the models were mounted to the correct VDO and horizontal plane, work could begin on a wax-up. The wax-up was constructed directly from the implant levels on the model (Figure 7). After the wax-up was completed, it was tried on the patient (Figure 8). At this point, aesthetics, occlusion, and phonetics were evaluated. The patient had a preview of the shape, size, and position of his proposed new smile and had the opportunity to provide feedback.

Once the patient approved the wax-up, final custom CAD/CAM abutments were designed and fabricated. Using CAD/CAM abutments eliminated many possible pitfalls, such as incorrect abutment selection, poor soft-tissue support, and concerns about dissimilar metal alloys and interfaces between cast and machined components. The working model of the implants and wax-up were scanned into a digital software package (TRIOS and Dental System [3Shape]). The abutments were then designed to fit into the necessary dimensions, as dictated by the implant positions and wax-up. The titanium abutments were milled and then placed using a seating jig (Figures 8 and 9). Radiographs were taken to confirm that the abutments were completely seated.

After this, the bridge metal framework was created for a full-arch restoration. It was initially constructed in 3 sections and then connected intraorally with acrylic (Figures 10 and 11). The lab technician then soldered the pieces together. To ensure a stable VDO during fabrication and to reduce the possibility of fractures after insertion, metal stops were placed on the second molars and the lingual of the anterior bridge. This step was clinically necessary to ensure proper fit prior to placing porcelain. After the fit and VDO were confirmed, porcelain was baked on the restorations and the restorations made ready for cementation.

For cementation, the individual abutments were inserted into the implants using a placement jig and torqued to 35 Ncm. The full-arch restoration was seated, and the margins, contacts, and occlusion were evaluated. Once the fit had been confirmed, the restorations were placed with try-in cement. The patient was given the opportunity to evaluate the restorations prior to cementation and was very pleased. Consequently, everything was cemented using a resin-reinforced glass ionomer cement (RelyX Luting Plus Cement [3M]). The cement was removed and occlusion checked. A nightguard was made to protect the new restorations from nighttime grinding. The patient was very pleased with the final results (Figures 12 and 13).

Figure 11. Try-in of the metal framework.	Figure 12. Facial view of the final restoration.

Figure 13. Occlusal view of final restoration.

IN SUMMARY
The proper approach to achieving the best possible smile for any aesthetic case must start with a full-smile analysis. Only when the practitioner determines the ideal final position of the teeth can the restorative phase begin. In this case, using provisional restorations and a transferable wax-up resulted in a final restoration that yielded optimal aesthetics, excellent function, and a very satisfied patient.

Acknowledgment
The author would like to acknowledge Dr. Kian Farzaneh (Danville, Calif) for being the oral surgeon involved with this patient, and Mike Sartip at Advanced Design Studio (Walnut Creek, Calif) for fabricating the restorations described in this article.

References

1. Fradeani M. Esthetic Rehabilitation in Fixed Prosthodontics, Volume 1. Esthetic Analysis: A Systematic Approach to Prosthetic Treatment. Chicago, IL: Quintessence Publishing; 2004.
2. Rufenacht CR. Fundamentals of Esthetics. Chicago, IL: Quintessence Publishing; 1990.
3. Hu J. A new day in dentistry: technology supports collaboration with the laboratory team. Dent Today. 2013;32:66-67.
4. Att W, Bernhart J, Strub JR. Fixed rehabilitation of the edentulous maxilla: possibilities and clinical outcome. J Oral Maxillofac Surg. 2009;67(suppl 11):60-73.
5. Cooper LF, De Kok IJ. Implant planning principles for the edentulous maxilla. Inside Dentistry. 2014;10:54-66.
6. Bedrossian E, Sullivan RM, Fortin Y, et al. Fixed-prosthetic implant restoration of the edentulous maxilla: a systematic pretreatment evaluation method. J Oral Maxillofac Surg. 2008;66:112-122.
7. Rohlin M, Nilner K, Davidson T, et al. Treatment of adult patients with edentulous arches: a systematic review. Int J Prosthodont. 2012;25:553-567.
8. Desai S, Upadhyay M, Nanda R. Dynamic smile analysis: changes with age. Am J Orthod Dentofacial Orthop. 2009;136:310-311.
9. Ray-Chaudhuri A, Mirza Z, Searson L. Options for temporization in the aesthetic zone after implant fixture placement. Dent Update. 2014;41:377.
10. Zafiropoulos GG, Galil AA, Deli G. An interocclusal recording method for the fabrication of full-arch implant-retained restorations. J Oral Implantol. 2014;40(special issue):357-364.

Dr. Javaheri graduated from Tufts University School of Dental Medicine in 1993. He then completed a 2-year advanced education in dentistry program at the University of the Pacific, San Francisco. He maintains a private practice in Danville, Calif, and is currently the course director of the implant and aesthetics continuing education programs at the University of the Pacific Dental School. He also serves as a consultant to many dental manufacturers and research organizations without remuneration. He has authored numerous articles for dental journals. He can be reached via email at the address drj@drjavaheri.com.

Disclosure: Dr. Javaheri reports no disclosures.