What an abutment does
The abutment is the part of an implant that rises above the gum line and connects the implant to the tooth on top.1 The FDA lists the abutment, and in some systems an abutment fixation screw, as parts of an implant system.2
Abutment materials
Abutments are made of titanium or of ceramics such as zirconia or alumina.3 A 2023 meta-analysis of randomized trials compared these materials.3
- No difference in bone level or gum pocket depth between titanium and zirconia or alumina abutments at 1 year or 5 years.3
- No difference in biological complications or appearance.3
- Ceramic abutments had abutment fractures as their main technical problem.3
Screw-retained and cement-retained
A crown or bridge is attached to its abutment in one of two ways.
- Screw-retained. A screw holds the restoration to the implant.4
- Cement-retained. The restoration is cemented onto the abutment, like a crown on a natural tooth.4
A systematic review of 73 studies found 5-year survival of 96.03 percent for cemented and 95.55 percent for screw-retained reconstructions, with no statistical difference.4 Screw-retained reconstructions had fewer technical and biologic complications overall.4
Cement left under the gum is associated with peri-implant disease.5 In one clinical study of implants with peri-implant disease, excess cement was found in 34 of 42 diseased sites.5 Thirty days after the cement was removed, signs of inflammation were gone in 74 percent of those implants.5
Multi-unit abutments
Multi-unit abutments are used under screw-retained full-arch bridges.7 Nobel Biocare describes its Multi-unit Abutment as a titanium abutment for edentulous and partially edentulous arches, made straight or angled at 17 or 30 degrees.6 The manufacturer describes it as key to its All-on-4 treatment concept.6
Titanium-base (Ti-base) abutments are a second option under screw-retained bridges.7 A 2026 meta-analysis of 684 implants found pooled bone loss of 0.68 mm under screw-retained zirconia bridges on Ti-base or multi-unit abutments, with no difference between the two.7
General information about dental implants. Treatment decisions are made with a licensed dentist.
Sources
- AAOMS (MyOMS.org): How Do Dental Implants Work?. myoms.org
- U.S. FDA: Dental Implants, What You Should Know. fda.gov
- Laleman I et al. Effect of different abutment materials on peri-implant tissues: systematic review and meta-analysis. Clin Oral Implants Res 2023. pubmed.ncbi.nlm.nih.gov
- Wittneben JG et al. Screw- vs cement-retained fixed implant reconstructions: systematic review. Int J Oral Maxillofac Implants 2014. pubmed.ncbi.nlm.nih.gov
- Wilson TG Jr. Excess cement and peri-implant disease. J Periodontol 2009. pubmed.ncbi.nlm.nih.gov
- Nobel Biocare (manufacturer): Multi-unit Abutment. nobelbiocare.com
- Rosa A et al. Marginal bone loss with Ti-base or multi-unit abutments: systematic review. Dent Med Probl 2026. pubmed.ncbi.nlm.nih.gov
