Comparison of retentive force and deformation of selective laser melting and conventional cobalt-chromium clasps of removable partial denture

Objective: The objective of the study was to compare the retentive force and deformation of conventional casting and selective laser melting (SLM) cobalt-chromium (Co-Cr) clasps assembly of removable partial dentures (RPD) following recurrent insertion and removal forces. Materials and methods: A total of 12 RPD samples were used in this study, which were divided equally into two groups: Group A (indirect digital conventional casting) and Group B (direct digital SLM) Co-Cr clasp assembly. The retention was measured using a universal testing machine after the recurrent removal and insertion of the RPD. Deformation was measured using Geomagic Control X professional metrology software. The retention and deformation data were compared between the two groups using an independent sample t-test. The association between the variables was studied using the Pearson correlation test. A statistical significance was established at P < 0.05. Results: A statistically significant difference in retention was observed between the two groups. Direct digital SLM Co-Cr clasp assembly showed higher retention and lower distortion compared to the indirect digital conventional casting Co-Cr clasp assembly. A significant negative correlation (correlation coefficient=-0.807, p-value = 0.004) between deformation and retention suggests that increased deformation reduces the retention. Conclusion: The direct digital SLM Co-Cr clasp assembly in the RPD showed higher retentive force and lower deformation than the indirect digital conventional casting Co-Cr clasp assembly in the RPD.