## 4 Discussion
These findings are in accordance with the study conducted by [PERSON] at el., which used M-One printer, resulting in greater marginal misfit of DLP-Cast than other groups tested [25]. [PERSON] et al. assessed the misfit using the weight of the silicone material and a digital microscope with sectioned specimens. Furthermore, it was also found that CAD-CAM displayed a significantly higher marginal misfit compared with Cast-LWT and SLM copings. This may be because correctness of internal and the marginal fit of copings produced through the subtractive technique depends on bur size. Any discrepancy in selection and size of burs relative to the size of coping results in compromised marginal properties [34]. Moreover, scanning and software system limitations related to finite resolution plausibly explicate the findings as these might result in margins with lower fit accuracy [35]. Many studies have compared the marginal or internal fit of coping and crowns fabricated from CAD-CAM and Cast-LWT [5; 12; 36]. Yet, it is challenging to conclude the findings of those studies due to variations in sample size, methods adopted to measure the marginal or internal gap, the type of cement used, and the CAD-CAM systems chosen. However, results of multiple previous studies are in line with the finding of the present study and displayed larger marginal or internal misfit for CAD-CAM fabricated prostheses than conventional techniques [12; 37; 38]. The influence of the different fabrication techniques on the Ra of CoCr copings have been addressed, proposing that Ra varies with the type of manufacturing technique [30]. Available literature also suggested that Ra values of any indirect prosthesis should be at least 0.2 \(\upmu\)m [39]. Ra is suggested to influence retention of restorations, but its effect on the marginal fit is not clear. In the present study, it was found that all fabrication techniquesdemonstrated Ra higher than the recommended threshold. Moreover, the difference in Ra values among different AM techniques, i.e., DLP-Cast and SLM, can be explained by different parameters adopted during fabrication [40]. It is suggested that the use of non-optimal parameters in any of the AM techniques result in porosity and an increase in the Ra of the prosthesis [41]. In the authors' opinion, decreased marginal misfit in SLM-fabricated copings may be due to the highest surface roughness obtained in this group. Similarly, surface roughness of copings fabricated from the CAD-CAM subtractive technique depends on the cutting speed and depth of the cutting [42]. Moreover, LWT copings displayed the lowest Ra score; this may be due to the favorable inlay wax surface properties along with strict adherence to manufacturer guidelines aiding low Ra [43]. The study showed that additive manufacturing methods like SLM and DLP-cast showed varying success in producing marginally accurate and smooth metal copings. The findings suggest that SLM copings have a good marginal fit and high roughness; however, DLP-Cast specimens display low roughness but a poor marginal fit. Therefore, both of these techniques need further development and can only be applied in limited clinical contexts. The findings of the study should be interpreted in light of the possible study limitations. In the present study, copings were manufactured under ideal circumstances and controlled conditions. In addition, the outcomes of the study are limited to the materials and techniques employed in the experiments. Therefore, to translate the findings of the present study into clinical recommendations, randomized clinical trials assessing the fit and adaptation of CoCr copings fabricated with additive manufacturing techniques are warranted.