Background: Minimal evidence exists on the efficacy of different digital manufacturing techniques in the fabrication of precise dental working models and provisional prosthesis. Aim of study: The objective was to evaluate the effect of two digital fabrication techniques (CAD/CAM milling and 3D printing) on the accuracy of PMMA working models and marginal fit of PMMA provisional prosthesis. Materials and methods: Two abutment teeth of modified typodont were prepared. A reference stone model was fabricated, and an optical impression was performed to obtain a CAD reference model. Four CAM milled working models and four printed working models were fabricated. CAD software was used to design the provisional prostheses. Group A tested four milled provisional prosthesis, and group B tested four 3D printed prosthesis. The 3D accuracy of working models was assessed by superimposition of the control reference working model on the CAD test working model. A stereo-optical microscope was used to assess vertical marginal fit of the provisional dental prosthesis. Student’s t and Mann–Whitney U tests were utilized to compare the two groups. Results: Results showed no statistically significant difference between the two tested groups. Conclusion: The two digital working model fabrication techniques recorded comparable accuracy. Similarly, 3D printed provisional prosthesis showed comparable marginal fit to the CAD/CAM milled ones.

Background: Different digital fabrication techniques affect the marginal adaptation of tooth supported provisional and final dental prosthesis. However, there is minimal scientific evidence which technique will be effective for producing tooth supported provisional dental prosthesis with predictable marginal fit. Aim of the study: to evaluate the effect of the two CAM fabrication techniques; milling versus 3D printing on the marginal fit of tooth supported restorations. Materials and methods: two abutment teeth of a modified typodont with a missing left mandibular first molar were prepared to receive a ceramic FDP. A master reference stone model was then, constructed. An optical impression (STL file) of the reference model was taken. A provisional tooth supported FDP was designed on the CAD software using the STL file of the reference model. Eight Restorations were fabricated by different CAM techniques. The restorations were divided into two groups according to the fabrication method; group A (milled restorations) (n=4) and group B (3D printed restorations) (n=4). Finally, the marginal fit of the provisional dental prosthesis was assessed by a stereo optical microscope on the stone reference model. Mann-Whitney U test was used to compare between the two groups. The significance level was set at P ≤ 0.05. Results: the results showed that there was no statistically significant difference between the vertical marginal gap values of the two tested groups. Conclusion: The vertical marginal gap values of provisional restorations fabricated by the two tested methods of manufacturing were comparable and within the acceptable range of 120 µ.