Fit of cobalt‑chromium copings fabricated by the selective laser melting technology and casting method: A comparative evaluation using a profilometer

This study aimed to assess the marginal adaptation and internal fit of cobalt‑chromium copings fabricated by the selective laser melting (SLM) and conventional techniques using a profilometer.

In this in vitro study sample size was calculated to be a total of 10 in two groups (n = 5). A brass model was used that had a circular cross‑section with a round shoulder margin with 0.5 mm thickness and axial walls with 10 mm length and 6° taper. The copings fabricated with both techniques (SLM and casting method) were placed on the model, and vertical marginal gap was measured using a profilometer. The internal fit of copings was assessed by weighing the light‑body addition silicone applied inside them, which simulated the cement. Data were analyzed through parametric (Independent t‑test) and nonparametric (Mann–Whitney U‑test, Bootstrap, Spearman, and Pearson Correlation) analysis. All analyses were performed at a significant level (α = 0.05) using SPSS.

The mean marginal gap in the casting group (132.93 ± ) was significantly higher than that in the SLM group (67.14 ± 15.67 µm) (P < 0.05). The mean weight of light‑body silicone was 9.60 ± in the SLM and 8.70 ± 1.21 mg in the casting group. No significant difference was noted between the two groups regarding the internal fit (P > 0.05).

The copings fabricated by the SLM technique showed a smaller vertical marginal gap compared to the casting group. However, the two groups were not significantly different in terms of internal fit.