Different kinds of implant abutments are available with respect to material (metal and ceramic) and shape (prefabricated and customized, both with various internal designs). Although metal abutments are classified as the gold standard, high-strength zirconia abutments are being utilized more widely.

However the available data in the literature only covers a limited time span. Therefore, the consensus statements and clinical recommendations are based on a review of the survival rates of metal and ceramic abutments supporting single-implant crowns with a mean observation period of at least 3 years.

• No differences were found between ceramic and metal abutments in clinical performance based upon esthetic, technical, or biologic outcomes.
• No differences were found between the clinical performance of metal abutments with external or internal connections, based upon esthetic, technical, or biologic outcomes (mean, 5 years [3 to 10 years]).
• The reported rate of technical complications is higher than either esthetic or biologic complications (mean, 5 years [3 to 10 years]).

• As many different types of zirconia with differing microstructures and performance are being introduced into implant dentistry, they should be obtained from a reputable/qualified manufacturer.
• For anterior and premolar prostheses, zirconia abutments may be indicated. However, they should not be ground, abraded, or adjusted by the clinician or technician following sintering, unless recommended by the manufacturer.
• Ceramic abutments should not replace metal ones for all indications. Preliminary findings reflect an inherent sensitivity of ceramics to design and processing problems; eg, stress concentration, thin walls, sintering, and residual machining flaws.
• The design of full ceramic abutments should not be based on metal abutment design to avoid stress concentrations or the development of unfavorable stresses.
• Caution is recommended in the clinical use of ceramic abutments in molar sites, as their behavior in these sites has not been sufficiently described.
• The performance of bonded titanium-zirconia implant abutments is not yet established. Thus, caution is recommended in the clinical use of such abutments due to insufficient data.