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Today’s ideal implant restorations demand the highest level of machining precision and the ability to withstand extreme functional and parafunctional forces while obtaining an outstanding esthetic match with natural teeth. While CAD/CAM technology has radically changed how these parameters are achieved, dental teams often make tradeoffs between strength (titanium) and esthetics (zirconia) when selecting abutment material. The introduction of “hybrid abutments” provides a solution to meet all these parameters and offers dental laboratories access to a simplified workflow with minimal-to-no capital investment.
The combination of an implant manufacturer’s proprietary titanium base (Ti-Base) and a customized zirconia coping provides the security and precise fit of an “original-to-original” interface between implant and abutment. The added security of a titanium-to-titanium connection matches the surface characteristics to reduce wear. This will maintain precise fit tolerance and minimize potential micromovement and associated negative biologic consequences. The mating of a zirconia coping (zerion®, Straumann®, www.straumann.us) created with CAD/CAM technology on the titanium base allows for precise placement of cement line, angulation correction with ideal support to the final cemented, or full-contour screw-retained restoration. This combination of titanium abutment and CAD/CAM-produced zirconia coping now allows for ideal esthetics with no compromise in strength even under excessive functional and parafunctional forces.
An ideal workflow enables any dental laboratory to provide these results to their dentists with no significant investments or changes to daily routine. The abutment design can be “waxed up” by the technician and sent to a Straumann CARES® scanning/milling facility for fabrication, or a traditional stone model can be sent to Straumann CARES Scan & Shape facility for design and fabrication. The technician is given the opportunity to view and approve the design prior to fabrication. Once the titanium base and milled zirconia coping are returned, the laboratory will simply bond the components together and fabricate the final restoration of choice.
The patient presented with a vertical root fracture of his maxillary right central incisor. The treating clinician chose to replace the tooth by placing a Straumann Roxolid® RC Bone Level Implant. The implant was placed with immediate provisionalization (RC Temporary Abutment VITA CAD-Temp®, Straumann), which was left out of any occlusal contact and allowed to integrate for 8 weeks. Because of the patient’s bruxism and the associated wear of the lower incisors, the dental team chose to restore the tooth using a CAD/CAM titanium-base abutment due to its strength. To satisfy the patient’s esthetic expectations, the dental team chose to place a lithium disilicate (IPS e.max®, Ivoclar Vivadent, www.ivoclarvivadent.us) crown, which made a full CAD/CAM zirconia coping appealing and allowed for elimination of underlying metal and the ability to maintain translucency in the final restoration. The selection of a VariobaseTM abutment (Straumann) provided the optimal mix of strength (Ti-Base) and esthetics (zirconia coping) with matched machining tolerance and surface characteristics between abutment and implant (Figure 1).
While a full-contour screw-retained restoration would eliminate any potential risk for cement below the peri-implant tissues and allow for simple retrievability, the screw-access position precluded this option. The technician used the Straumann CARES Scan and Shape online service to accomplish the design and fabrication of the CAD/CAM zirconia coping with ideal cement line position and support for the restoration (Figure 2). A “stump” shade was provided to the technician for selection of the zirconia color as well as a final shade for fabrication of the definitive lithium disilicate crown (IPS e.max). The technician bonded the milled zirconia coping to the Ti-Base abutment (Panavia Kuraray Dental, www.kuraraydental.com), and then inspected and removed residual adhesive using magnification and returned the abutment and crown for delivery to the patient (Figure 3). The abutment (Ti-Base with adhesively attached zirconia coping) was delivered to the clinician, torqued to 35 Ncm, with the screw access sealed (Clip, Voco, www.voco.com) and an IPS e.max crown cemented (Figure 4).
The preceding case illustrates a blending of current science, art, and technology to allow any dental team to provide uncompromised strength, precision of fit, and esthetics with long-term biologic and mechanical stability.
This article was supplied by Straumann.
About the Authors
Robert Vogel, DDS
Robert Vogel, DDS, graduated from the Columbia University School of Dental and Oral Surgery in New York City, New York. After graduation, he completed a combined residency program in Miami, Florida at Jackson Memorial Hospital, Mount Sinai Medical Center, and Miami Children’s Hospital. He maintains a full-time private practice in implant prosthetics and reconstructive dentistry in Palm Beach Gardens, Florida. He works closely as a team member with several specialists providing implant-based comprehensive treatment, as well as conducting clinical trials and providing clinical advice to the dental attachment and implant fields. Dr. Vogel has developed and collaborated on the development of several prosthetic components and techniques currently in use in implant dentistry. He lectures internationally on implant dentistry, focusing on simplification, confidence, and predictability of implant prosthetics through ideal treatment planning and team interaction. Dr. Vogel continues to publish scientific articles on implant dentistry and is a Fellow of the International Team for Implantology.
Marcos Aleman, CDT
Marcos Aleman, CDT, has been president of Aleman Dental Lab., Inc. since its inception in 1996. Aleman Dental is a laboratory committed to embracing digital technology while maintaining the knowledge of the past. It provides integrity of work and service through flawless and well-crafted restorations.