Conus Abutments: a Fixed, Hygienic, Restorative Solution
Unique restorative innovations meet unique individual needs
By Lars Bouma, DDS
Restorative dentistry has always been the art and science of restoring dental patients to their optimal masticatory function, esthetics, and overall health. Recent restorative innovations and dental implant advances have afforded cases proven to previously be difficult to achieve patient expectations and overall biomechanical oral health and success. Dental patients present at the dental office with failing dentition caused by an assortment of causalities; whether it be genetic, diminished or nonexistent dental care, trauma, and/or medicinal induced failures. Dentists are tasked with providing a treatment protocol and solutions to restore the patient to proper function.
Meeting the Patient's Needs
The patient was a 61-year-old paraplegic, wheelchair-bound due to a debilitating automobile accident 15 years earlier. Side effects from medication led to failed dentition, but full removable dentures were not acceptable for various reasons. Due to extreme financial considerations, fixed implant options were not viable. The author decided to present a fixed, hygienic solution option to the patient, using four Ankylos® implants (Dentsply Sirona; dentsplysirona.com) in each arch, in conjunction with the Atlantis® Conus concept, incorporating patient-specific abutments and friction cap with his new dentures.
This implant treatment protocol would allow the Conus attachments to be embedded into the dentures and allow the dentures to actively engage the implants, providing a fixed feeling for the patient and the ability to remove the dentures to clean them. Since the patient had the use of one hand, this was a great solution for him.
The author chose this treatment protocol using the Atlantis Conus concept because the abutments allowed one path of insertion irrespective to the angle of surrounding implants due to being specifically customized for the individual. In this patient's case, the maxilla implants were not parallel due to anatomic limitations. Conus patient-specific abutments were able to be angulated for the correction of implant alignment. Lack of parallel paths of insertion between implants will wear components more quickly and cause them to ultimately fail. Conus abutments and friction caps allow for a truly passive draw.
The Restorative Process
Upon healing from implant placement, an open tray multi-viscosity impression was taken of the upper and lower arches using Aquasil® Ultra XLV Extra Low Viscosity (Orange), Aquasil Ultra LV Low Viscosity (Aqua) and Aquasil Ultra Monophase Viscosity (Purple) regular set (Dentsply Sirona), a vinyl polysiloxane (Figure 1). Figure 2 shows the CBCT scan and Figure 3 shows the healing abutments. The impressions were cast using type four (IV) gypsum improved stone. Laboratory implant analogs for the Ankylos implant system were used to reproduce the implants' rotation, position, and depth in the model, and moulages were placed using Aquasil Ultra XLV Extra Low Viscosity (Orange) fast set (Dentsply Sirona) to reproduce the soft tissue around the necks of the implants.
The completed implant models were then sent to Atlantis, along with a clear mock-up of the patient's expected final result. These are both critical components; Atlantis will scan the models using FLOs (fixture-level orientation scan flags) in order to establish the exact placement and orientation of the implant and then scan the mock-up into the system. With that done, the digital designer at Atlantis can align the abutments to be parallel and exhibit the same grouped path of insertion. Once the digital design is completed and approved by the laboratory and/or dentist (Figure 4 and Figure 5), it is then submitted through Atlantis WebOrder to manufacture the patient-specific Conus abutments for optimal retention of the overdenture and sent back to the dental laboratory.
The author retrieved the abutments and tried them to make sure everything fit well. Once proper fit was determined, the Conus caps with friction fit were placed over the abutments, and the denture the patient had been wearing was relined over the top of the Conus components. A pick-up impression was made again using the Aquasil vinyl polysiloxane, and the friction fit caps were blocked out of any undercuts, ensuring non-engagement that could potentially cause the locking of components with the impression material (Figure 6 through Figure 11).
Subsequently, the dental laboratory poured a stone model from the pickup impression, and the denture was relined with heat-cured Lucitone 199 by investing, flasking, and heat packing the acrylic. Once relined, the author marked around the peripheral of the cap and removed approximately 1 mm to 2 mm to allow a little space around the Conus friction caps. Polymerization sleeves were placed in the mouth around the implants to ensure that acrylic didn't seep into or around the implants, adhesive was painted on the acrylic and cap, chairside processing material was mixed and placed within the cap sites, and, finally, everything was seated back in the mouth. Five minutes were allowed for proper setting and the process was repeated for the opposite arch; both were pulled out and any excess was trimmed.
The patient was ecstatic with the outcome of his case (Figure 12). He said that it was like having his own teeth again, and was able to eat and function like he did before the accident. "I can eat anything," he said. This fixed, hygienic solution is a very simple and easy restorative way to provide the patient with the ability to clean his teeth as a normal denture, while offering the security of a fixed bridge. With the mobility and financial challenges of the patient, this restorative solution was the ideal treatment solution that immediately affected his life tremendously.
Disclaimer: The statements and opinions contained in the preceding material are not of the editors, publisher, or the Editorial Board of Inside Dental Technology.
About the Author
Lars Bouma, DDS, is a practitioner at Implant and Prosthodontic Associates in Oklahoma City, Oklahoma.
Manufacturer Contact Information
Dentsply Sirona Implants