Clinical wear of overdenture ball attachments after 1, 3 and 8 years

Clin Oral Implants Res. 2011 Nov;22(11):1270-4. doi: 10.1111/j.1600-0501.2010.02102.x. Epub 2011 Feb 24.


Objectives: Implant-supported overdentures have become the treatment of choice in restoring complete edentulism, but the types of attachment to assure durable retention are a subject of debate. Ball attachments were reported as a simple treatment, but wear of components was responsible for a decrease in retention. The aim of this retrospective study was to measure the wear of the ball abutment or patrix after three different periods of clinical wear.

Material and methods: Sixty-nine specimens of three groups of patrix that were in use for a mean of 12.3 months (group A), 39 months (group B) and 95.6 months (group C) were retrieved from 35 patients and measured on a coordinate measuring machine equipped with a touch trigger probe. Ten unused ball abutments were added as a control (group D). The patrix diameters and any deviation from circularity in different axes were measured.

Results: The diameters of groups A, B and C were significantly different from that of group D (control). No statistically significant differences were found between diameter and circularity variations between groups B and C. The maximal amount of diameter reduction was limited to approximately 30 μm, and 90% of diameter loss at the equator due to wear was reached in group B.

Conclusion: One, 3 and 8 years of clinical wear reduced significantly the diameters of the ball abutments tested, and the maximal amount of wear was reached after 3 years of clinical use.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Dental Implants
  • Dental Prosthesis, Implant-Supported*
  • Dental Restoration Wear*
  • Denture Retention / instrumentation*
  • Denture, Overlay*
  • Follow-Up Studies
  • Humans
  • Retrospective Studies
  • Surface Properties


  • Dental Implants