Influence of Abutment Design on Stiffness, Strength, and Failure of Implant-Supported Monolithic Resin Nano Ceramic (RNC) Crowns

Clin Implant Dent Relat Res. 2015 Dec;17(6):1200-7. doi: 10.1111/cid.12215. Epub 2014 Mar 14.


Background: Recent technical development allows the digital manufacturing of monolithic reconstructions with high-performance materials. For implant-supported crowns, the fixation requires an abutment design onto which the reconstruction can be bonded.

Purpose: The aim of this laboratory investigation was to analyze stiffness, strength, and failure modes of implant-supported, computer-assisted design and computer-aided manufacturing (CAD/CAM)-generated resin nano ceramic (RNC) crowns bonded to three different titanium abutments.

Materials and methods: Eighteen monolithic RNC crowns were produced and loaded in a universal testing machine under quasi-static condition according to DIN ISO 14801. With regard to the type of titanium abutment, three groups were defined: (1) prefabricated cementable standard; (2) CAD/CAM-constructed individualized; and (3) novel prefabricated bonding base. Stiffness and strength were measured and analyzed statistically with Wilcoxon rank sum test. Sections of the specimens were examined microscopically.

Results: Stiffness demonstrated high stability for all specimens loaded in the physiological loading range with means and standard deviations of 1,579 ± 120 N/mm (group A), 1,733 ± 89 N/mm (group B), and 1,704 ± 162 N/mm (group C). Mean strength of the novel prefabricated bonding base (group C) was 17% lower than of the two other groups. Plastic deformations were detectable for all implant-abutment crown connections.

Conclusions: Monolithic implant crowns made of RNC seem to represent a feasible and stable prosthetic construction under laboratory testing conditions with strength higher than the average occlusal force, independent of the different abutment designs used in this investigation.

Keywords: DIN ISO 14801; abutment connection; dental implants; failure mode; resin nano ceramic (RNC); stiffness; strength; titanium.

MeSH terms

  • Ceramics
  • Composite Resins
  • Computer-Aided Design
  • Crowns*
  • Dental Implant-Abutment Design*
  • Dental Prosthesis, Implant-Supported*
  • Dental Restoration Failure
  • Dental Stress Analysis
  • In Vitro Techniques


  • Composite Resins