ABSTRACT
Introduction: When treating edentulisum, severely resorbed mandibular ridges are a prevalent issue. Attachments could be used to enhance retention. For removable distal extension prosthesis, extra coronal attachments enhance retention. During mastication and removal, micro and macro movement between the retentive surfaces of an attachment causes wear and reduces the retentive capacity over time. Using CAD/CAM technology, more accurate frameworks with improved retention should be expected.
Objective: was to compare the retention of conventional and CAD/CAM fabricated extra coronal attachments for a removable partial denture.
Methodology: - Retention of four extra coronal attachments of different materials and methods of fabrication was evaluated. The attachments were divided into two different groups according to the material used and whether the attachment was fabricated using the conventional method or CAD/CAM technology. Using a Universal testing machine, the difference in retention was compared between the groups.
Results: Data was collected, tabulated, and statistically analyzed using the appropriate test. In group I the mean force needed to dislodge the female clip before and after cyclic loading was 46.69N and 32.13N respectively and in group II the mean force needed was 59.07N and 42.44N respectively.
Conclusion: In comparison to conventional extra-coronal attachment, CAD/CAM fabricated extra-coronal attachment had a highly significant retentive force.