While hidden, implant abutments are an essential component to implant therapy. They connect the implant to the prosthetic dental crown. At ARIA, we focus on the different abutment designs and materials available, and its significance.
Components
Implant abutments consist of three parts:
- Implant connection segment
- Transgigival segment
- Prosthesis connection segment
(Shafie, Abdel-Azim, & Chapman, 2014)
While the implant connection segment cannot be altered, the other two portions can be to enhance aesthetics and stability. A modified transgingival segment can accommodate oral hygiene, gingival thickness above the implant, and the emergence profile of the prosthetic tooth (Shafie et al., 2014). Changing the prosthesis connection segment can enhance the emergence profile, inter-occlusal space, shape of the interdental papillae and gingival embrasure. While this may all seem overwhelming, our specialist periodontist and prosthodontic lecturers can help you decide on the best design for your patient.
Design
Our implant courses in Melbourne and Adelaide also stress how the design must support the soft tissue architecture. Since the abutment affects the gingival architecture, it is usually concave except on the buccal surface where it is convex. This develops the contours for the provisional restoration, which then supports the ideal tissue form. If placed soon after an extraction, the biologic width may also form along the abutment. Soft tissue thickness can be guided by the 3:2 rule (Cooper, 2008). The biologic width should be 3mm along the abutment, while the implant connection segment should be 2mm from the gingival zenith. This better ensures adequate thickness of bone and mucosa to support the tissue form, and may act as an indication for bone or soft tissue grafting (Cooper, 2008).
Materials
Two of the most common abutment materials are titanium and zirconia due to their biocompatibility and mechanical strength. Zirconia also has the added benefit of less gingival discoloration at the site. (Bharate, Kumar, Koli, Pruthi, & Jain, 2020)
Stock vs Custom
Two main types of abutments are stock and custom abutments. Our specialist dental lecturers may recommend these due to its cost-effectiveness and ability for chairside modifications. Nevertheless, emergence profile and aesthetics are harder to achieve. These abutments should only be utilised if the implant placement is very accurate, allowing minimal reduction and modification. Over-reduction of the abutment can otherwise affect its structural integrity, resistance and retention.
Customised abutments, although more expensive, are becoming increasingly popular due to its increased metal quality, strength, and durability. Since they are made individual for each implant site, its accuracy increases aesthetics and stability. There is greater ability to adjust the emergence profile at the transgingival segment, the margin level placement, and angulation corrections. These are commonly UCLA or CAD/CAM (Computer-Assisted Design and Computer-Assisted Manufacturing) fabricated. The increased use of digital technology to form these abutments reduces the reliance on technique-specific processes to obtain the desired result (Toronto Osseointegration Conference, 2009).
Therefore, the choice of implant abutment will ultimately depend on implant, site and patient factors.
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Images courtesy of Dr Praveen Nathaniel
References
Bharate, V., Kumar, Y., Koli, D., Pruthi, G., & Jain, V. (2020). Effect of different abutment materials (zirconia or titanium) on the crestal bone height in 1 year. J Oral Biol Craniofac Res, 10(1), 372-374. doi:10.1016/j.jobcr.2019.10.001
Cooper, L. F. (2008). Objective Criteria: Guiding and Evaluating Dental Implant Esthetics. J Esthet Restor Dent, 20(3), 195-205. doi:10.1111/j.1708-8240.2008.00178.x
Shafie, H. R., Abdel-Azim, T., & Chapman, M. (2014). Clinical and laboratory manual of dental implant abutments: Ames, Iowa : Wiley Blackwell.
Toronto Osseointegration Conference, R. (2009). Osseointegration and dental implants. Ames, Iowa: Ames, Iowa : Wiley-Blackwell.
