Introduction:
Development of digital imaging, designing and manufacturing techniques have led to the possibility of manufacturing prosthetic restorations without the need for conventional laboratory procedures. One of the methods of production is the technology of laser sintering of metal powders – Direct Metal Laser Sintering (DMLS). With the use of CAD/CAM systems, it can replace the traditional technique of casting the crown substructure with the lost wax technique.

Aim of study:
To compare the compatibility of the digital design of prosthetic crowns with restorations made with the use of laser sintering technology (DMLS).

Materials and methods:
The study material consisted of five prosthetic crowns made in DMLS technology based on the intraoral scan. Internal surfaces of the restorations were scanned using a laboratory scanner. The obtained point clouds in the form of a mesh of internal surfaces and crown designs in the form of CAD models were sent to the GOM Inspect 2018 software. Design matching (CAD models) with scans of their internal surface was made for each crown. In this way, a heat map was obtained, illustrating the deviations between the compared models and meshes.

Results:
The first and the fifth crowns were characterized by an average deviation of 0.00 ± 0.03 mm and 0.00 ± 0.05 mm, respectively. The highest mean deviation was obtained when the second crown was measured, i.e. 0.03 ± 0.02 mm. The highest maximum positive deviation was recorded for the fourth crown, whose value was 0.12 mm, while the largest negative deviation was observed in the first and the fifth crowns – this value was -0.10 mm.

Conclusions:
Analysis of the compatibility of digital designs with ready-made crowns showed that laser sinter technology enables the fabrication of crowns with accuracy corresponding to the presented results. Failure to obtain a statistical constant value of the deviation makes it impossible to determine the error occurring at the stage of manufacturing of the prosthetic restoration in DMLS technology. The application of the described method allows virtual control of the degree of fit of the prosthetic restoration before placing it in the patient’s mouth.