title: Analysis of retention and wear of ball attachments.
abstract: OBJECTIVE
  To evaluate the retention and the wear of different prefabricated precision ball attachments consecutively during long-term use.
  
  
  METHODS
  Six commercially available ball attachment systems were selected. The balls were attached to stylized implants fixed in metal casts. The matrices were fixed in a stylized unilaterally removable partial denture (RPD). Using a chewing simulator with 8 units, 50,000 joining and separating cycles of the matrices were performed. After each joining movement, an eccentric load of 100 N was applied to the RPD at a distance of 12 mm from the ball attachment. The retention forces were measured at intervals.
  
  
  RESULTS
  Initially, median retentive forces varied between 8.2 N and 14.0 N. During the test, patterns in retention changes were identified. At the end of the test, one group with a matrix using precious alloy lamellae and a titanium ball showed significantly higher median retention forces (10.4 N) than the other ball attachments (1.0 N to 3.7 N). Also, the wear of the ball attachments varied considerably.
  
  
  CONCLUSIONS
  Within the limitations of this study, the material combination of a precious gold alloy matrix and a titanium ball seems to be favorable for long-term retention.
authors: Department of Prosthodontics, Propaedeutics, and Dental Materials, School of Dentistry, Christian-Albrechts University, Kiel, Germany. kwolf@proth.uni-kiel.de
authors: Katia
authors: K
authors: Wolf
authors: Klaus
authors: K
authors: Ludwig
authors: Heike
authors: H
authors: Hartfil
authors: Matthias
authors: M
authors: Kern
mesh_terms: D003722:Dental Alloys; D017268:Dental Prosthesis Retention; D019094:Dental Prosthesis, Implant-Supported; D019554:Dental Restoration Wear; D003799:Dental Stress Analysis; D003834:Denture Precision Attachment; D006801:Humans
chemical_list: D003722:Dental Alloys