Retention and Deformation of Cobalt-Chromium and High-Impact Polyamide Clasps

Objective: The use of metal clasps especially in anterior region may cause aesthetic problems. Polyamide resin has been suggested as an alternative aesthetic denture clasp material. This study compared the retentive force and deformation of cobalt-chromium and polyamide clasps after 36 months of simulated clinical use. Materials and Methods: The retentive force for clasp removal was measured in distilled water using a custom-made apparatus with intervals corresponding to 0, 6, 12, 18, 24, 30 and 36 months of simulated clinical use. The distance (mm) between the retentive and reciprocal clasp tips was measured using a microscope before and after the insertion-removal procedures. Results: Significant difference was observed in distance between clasp tips for metal clasps between baseline and 36 months for molars and premolars (p<0.05). Likewise, retentive force showed significant difference (p<0.05) for cobalt-chromium between baseline and 36 months, while polyamide clasps did not show significant difference (p>0.05). Conclusion: Polyamide clasps could be alternative to metal clasps particularly on premolars with reliable retention and deformation