## 4 Discussion  
The present study investigates the influence of fabrication techniques--CAD-CAM, conventional, and 3D printing--on the surface property and marginal integrity of interim crowns. These samples were evaluated for three different physical properties: surface roughness, marginal misfit, and adaptation and surface wear. The techniques were compared to establish the superior efficacy of the techniques and their influence on interim restoration's long-term success. It was hypothesized that fabrication techniques have an influence on marginal fit and adaptation, surface roughness, and wear properties. Nevertheless, the outcome presented that 3D printing showed superior efficacy to CAD-CAM and conventional techniques in terms of marginal fit and adaptation and surface wear. However, the highest surface roughness was observed in 3D-printed specimens, followed by conventional and CAD-CAM specimens. Hence, the null hypothesis was rejected. The present study further demonstrated that the conventional technique and CAD-CAM produced comparable outcomes for crown adaptation to the tooth's surface, and 3D printing produced superior adaptability. However, 3D printers and CAD-CAM showed similar results compared to the higher conventional crown misfit. In light of medical literature, the manual preparation of the interim restoration, trimming off the excess and removal during the setting time, is the main reason for the distortion and misfit of the crown [18]. Thus, modern technology such as CAD-CAM and 3D printing produces a better marginal fit and adaptation due to precise milling and software designing. Compared to the previous in vitro studies, other factors that influence the marginal adaptation of the interim crown include the finishing margin of the crown after the curing process, force applied to facilitate during the cementation, and repeated measurements using a microscope [2]. As stated by [PERSON] et al. (2015), the increased application of cement increases the risk of a marginal gap. Hence, in the present study, we did not employ cement in order to  
Figure 13: Scatter plot for the correlation between marginal misfit and surface roughness for the CN samples. eliminate the influence of cement [2]. Nevertheless, the outcome of the study cannot be directly compared with previous findings because of the difference in sample size and the fabrication techniques employed. It is reported that a minimum marginal discrepancy for interim restoration is between 50 and 120 \(\upmu\)m [3]. In contrast, in the present study, the mean value for the three fabrication techniques ranged from 200 to 300 \(\upmu\)m, with a minimum value of approximately 180 \(\upmu\)m. A study by [PERSON] (2017) showed that the high discrepancy was mainly due to the difference in tooth surface preparation, with an average difference of 120 \(\upmu\)m [3]. Thus, it was concluded that material and fabrication techniques play an important role in influencing marginal misfit. Nevertheless, despite the effort, over time, the interim crown tends to wear off, leading to marginal misfits. Furthermore, in the present study, micro CT was employed to assess marginal integrity and internal adaptation. This is a noninvasive and reliable method to establish a nominal marginal gap. The technique produces a high-resolution product without disturbing the integrity of the restoration; its fabrication is uncomplicated, and no sample preparation, as a replica technique with assembly is being sectioned, is required [4; 19]. In addition, this is the only method to reconstruct a master model die and its suprastructure three-dimensionally [20]. The technique is integrated with a system that slices the specimen to overview each slice for a uniform understanding of fitting and marginal gap presences [5]. Regardless, studies showed that no significant difference was found between the two techniques--micro CT and replica technique--in assessing the marginal misfit [4; 5].