Inside Dentistry

September 2011, Volume 7, Issue 8
Published by AEGIS Communications

Using Denture Teeth and ANKYLOS Implants to Achieve Esthetics and Function

Traditional methods and the use of advanced materials and modern prosthetic tooth designs provide patients with enhanced care.

By David Little, DDS; Troy Apparicio, CDT

Implant-supported overdentures provide tremendous benefits over traditional denture materials and techniques.¹ By combining osseointegrated implants under removable prostheses, the resulting bone preservation, prosthetic retention, stability, and occlusal support provide patients with improved quality of life, self-confidence, a healthier nutritional state, and facial esthetics nearly parallel to those of natural dentition.^1-3 Patients also have found implant-supported and retained prostheses more comfortable, enabling them to function normally unlike dentures of the past.¹

Today’s stronger materials can withstand implant forces while demonstrating higher wear resistance, enhanced esthetics, and better bite characteristics.^2-4 In addition, implant-retained overdentures provide a more comfortable fit and improved biocompatibility as a result of newer denture base materials and tooth technology.^1,4

With computer-aided design/computer-aided manufacture (CAD/CAM) technology, denture teeth can be designed for advanced occlusal schemes. Because dentures can now be made from denser materials,⁴ decreased incidences of breakage can be expected. Today’s advanced materials and placement techniques provide the necessary improvements edentulous patients have needed.^4,5

Premium and Mondial Denture Teeth

Fabricated from inorganic nano-fillers integrated in a highly cross-linked, tough elastic matrix, Premium and Mondial^® denture teeth (Heraeus, www.heraeus-dental-us.com) demonstrate lifelike opalescence, high abrasion resistance, biocompatibility, plaque resistance, and color stability. Harmonious tooth set-up and reproducible articulation are guaranteed because these dentures are fabricated using CAD/CAM technology.

Based on the highly successful Magister/Orthognath molds (Heraeus) used worldwide for more than 40 years, improvements in esthetics, function, and material quality are significant with the Mondial denture teeth. By modifying the labial, buccal, and occlusal surfaces and restructuring the layering to match the Vita Classical Shade Guide (Vident™, www.vident.com), opalescence is greatly improved. Integrated nano-fillers impart optical qualities resulting in attainable depth and lifelike color.

For improved function, Mondial denture teeth feature a precisely defined centric relationship for clear-cut set-up. Identical sets of teeth are easily created with identical shaping for all tooth sizes. High functional accuracy is achieved through CAD/CAM design so that Mondial denture teeth have no frictional surfaces, which resist function.

Advanced nano-pearls ensure Mondial dentures are highly abrasion resistant without modifying hardness or elasticity, which is a common problem in conventional polymethyl methacrylate (PMMA) materials. However, the attainable polish is still similar to that achieved with PMMA dentures. As a result of nano-pearls, the material also demonstrates improved bond strength between layers for improved retention rates.

With natural light dynamics and high resistance to discoloration, Mondial denture teeth give patients more natural-appearing prostheses. Also, with the INCOMP manufacturing process, bubble- and porosity-free prostheses that mimic the patient’s own dentition can be expected.

Case Presentation

A 64-year-old man presented for a second opinion and the desire to restore his lower arch with implants. The lower arch displayed severely crowded natural dentition with advanced periodontitis, caries, and resorbed posterior ridges. The initial examination of the mandibular arch also revealed deep pockets, bleeding, and mobility evident upon probing. Radiographic diagnosis revealed significant bone loss in the posterior areas.

Treatment Planning

A comprehensive examination was performed, which included a clinical examination, digital panoral radiographs, full-mouth radiographs, and photographs. An oral cancer screening was performed with negative findings. A cone-beam scan was also performed.

Extraction of the mandibular teeth was indicated and the minimum treatment recommended was an immediate denture. The patient opted for an implant-supported denture.

The treatment plan involved extractions and placement of implants in the anterior mandible to preserve bone and support the lower denture. An immediate implant-supported denture was fabricated for delivery at the time of the extractions and implant surgery to serve as an interim prosthesis during the healing period. Later, a definitive screw-retained prosthesis would be fabricated.

Implant Placement

Surgical procedures, including extractions and radical alveoplasty, were performed. The case was treatment planned for five implants in the mandible using SimPlant^® software (Materialise Dental, www.materialise.com). Five ANKYLOS^® implants (DENTSPLY Friadent, www.dentsply-friadent.com) were then placed in the lower arch.^6-9

After placement, four of the implants were immediately loaded using overdenture abutments (ANKYLOS^® SynCone, DENTSPLY Friadent).^7-9 Four SynCone conical overdenture abutments were then placed over the implants in sizes that had been determined by the SimPlant case planning software and verified with try-in abutments. A 1-mm hex prosthetic ratchet was used to torque the abutments to 15 Ncm. SynCone gold caps were placed on the conical abutments and covered with protective flexible polymerization sleeves to prevent soft tissue damage.⁶

A window was then created in the transitional lower denture to create space for the acrylic to pick up the gold copings. The recorded vertical dimension of occlusion was verified before a cold-cure acrylic was mixed and placed in the transitional denture. Once the acrylic had polymerized, the transitional overdenture was removed with a crown-tapping device, trimmed, polished, and reseated (Figure 1).⁶

One of the major benefits of using an implant-supported mandibular denture is that it can be delivered and worn out of the office the same day the implants are placed. After the placement of the implants, abutments, and transitional dentures, the patient was allowed to heal, and periodic in-office visits provided feedback regarding the healing progress and fit of the provisional denture.

Definitive Denture

The patient’s maxillary arch had been previously restored with a full-arch implant-supported porcelain-fused-to-metal fixed partial denture and he wanted similar results in the mandible. Therefore, a hybrid denture was indicated to meet the functional requirements of the mandibular arch. The lower arch also required restoration with prosthetic teeth capable of withstanding the occlusal and functional forces expected when opposing ceramic restorations on the maxillary arch.¹⁰

Common issues faced with hybrid dentures include broken prosthetic teeth and delamination or debonding of the prosthetic teeth at the interface of the acrylic resin material (Figure 2).¹⁰ The latter is typically caused by cyclic fatigue over time and can be attributed to poor bond strength between materials.

Teeth Selection

It was decided that inorganic nano-filled prosthetic teeth (Mondial) would be used in this case. In the author’s opinion, these prosthetic teeth display lifelike quality that is unsurpassed. The anatomy of both the anterior and posterior are well designed and anatomically correct from all aspects (including the lingual) as well as esthetically pleasing. Through observation, it is clear that the anterior sets have been developed with methodical attention to the layering detail. The deep dentinal material is layered in a way that is natural-looking and the mamelon structures are complimented by the translucent enamel. When the tooth is in its natural environment, the opalescent and fluorescent properties exhibit a very lifelike and natural appearance (Figure 3).

Mondial denture teeth are also robust in design, making them ideal for implant-supported restorations. They are very dense in the center as a result of high compression in the molding process, displaying no voids or unpolymerized resin that may be occasionally seen in some prosthetic teeth. The nano-pearl technology imparts a tough fracture resistance property to the teeth, similar to shock absorbers in automobiles. Unlike technologies that incorporate one large elastic particle, the nano-pearl is composed of small rubberized particles bound together with the same material used to construct the tooth, which contributes to longer wear resistance.

Laboratory Protocol

The hybrid framework was fabricated using conventional methods. After the fit was clinically verified, a bite registration was taken using the cast hybrid bar and polyvinyl siloxane material, using the measurements from the existing vertical dimension of occlusion and centric relation.

The patient opted for a natural set-up, with slight overlapping and rotation, negating the rigid set-up typically seen in dentures. The anterior set-up was accomplished easily (Figure 4) and the posterior teeth were also set, minimizing the need for gross equilibration. Minimal perforation provided access for the retaining screws, which were used to secure the frame to the implants (Figure 5 and Figure 6).

The hybrid denture was flasked using laboratory stone in a conventional brass denture flask, and the wax was eliminated through boiling (Figure 7 and Figure 8). The framework was removed from the mold, which was treated with aluminum oxide on the surface to accommodate the resin material. The definitive bar was steamed, cleaned, etched, and primed using a thiophosphoric methacrylate primer (Metal Primer II, GC America, www.gcamerica.com). A Ropak UV Light-Cure (Bredent, www.bredent.com) was completed to increase the bond strength of the acrylic resin to the hybrid bar and mask out its grayness, enhancing the overall color of the acrylic resin base material (Figure 9).

The hybrid denture was processed and allowed to cure overnight at 165o F for 10 hours to decrease the level of free monomer in the base material, and then bench cooled before recovering. It was remounted on the articulator and checked for any occlusal discrepancies, correction of any processing errors, and removal of flash and excess base material (Figure 10). The denture was then polished and prepared for final delivery (Figure 11, Figure 12, Figure 13).

Delivery

The interim denture was retrieved and the SynCone abutments removed and replaced with the ANKYLOS^® Balanced Base abutments (DENTSPLY Friadent) used during laboratory fabrication of the hybrid bar. The hybrid denture was secured to the abutments with screws and isolated with cotton pellets. The access holes were then sealed with composite, achieving clinical delivery of the permanent prosthesis (Figure 14).

Conclusion

This patient’s treatment was based on years of clinical experience and objective clinical data. The combination of laboratory experience with traditional methods and the use of advanced materials and modern prosthetic tooth designs created using CAD/CAM technology provide patients with enhanced care. By following a protocol of long-term provisionalization, the dental team delivered an immediate and stable solution followed by successful delivery of the definitive prosthesis.

References

1. Vogel RC. Implant overdentures: a new standard of care for edentulous patients current concepts and techniques. Compend Contin Educ Dent. 2008;29(5):270-276.

2. Henry K. Q&A on the future of implants. Dental Equipment and Materials. 2006;September/October.

3. Rossein K. Alternative treatment plans: implant supported mandibular dentures. Inside Dentistry. 2006;2(6):42-43.

4. DiMatteo A. Dentures & implants: bringing them together for a winning combination. Inside Dentistry. 2009;5(1):97-104.

5. Fiske J, Davis DM, Frances C, Gelbier S. The emotional effects of tooth loss in edentulous people. Br Dent J. 1998;184(2):90-93.

6. Little D. Immediate outcomes: using flapless surgery and ankylos syncone overdenture abutments. Inside Dentistry. 2007;3(10):108.

7. Mericske-Stern R, Assal P, Buergin W. Simultaneous force measurements in 3 dimensions on oral endosseous implants in vitro and in vivo. a methodological study. Clin Oral Implants Res. 1996;7(4):378-386.

8. Feine JS, Carlsson GE, eds. Implant Overdentures: The Standard of Care for Edentulous Patients. Hanover Park, Il: Quintessence Pub Co, Inc; 2003.

9. Adell R, Lekholm U, Rockler B, Branemark PI. A 15-year study of osseointegrated implants in the treatment of the edentulous jaw. Int J Oral Surg. 1981;10(6):387-416.

10. Piermatti J. Tooth position in full-mouth implant restorations - a case report. Gen Dent. 2006;54(3):209-213.

About the Authors

David Little, DDS
Private Practice
San Antonio, Texas

Adjunct Clinical Professor
University of Texas Health Sciences Center San Antonio Dental School
San Antonio, Texas

Troy Apparicio, CDT
San Antonio, Texas

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