Accuracy of 3D printed polymers intended for models and surgical guides printed with two different 3D printers

The purpose of the study was to evaluate the accuracy: trueness and precision of photopolymers used for dental models and surgical guides printed with two different digital light processing (DLP) printers. Forty specimens of four materials; E-dentstone^®, E-shell^®, NextDent™ Model, NextDent™ SG, and two designs; models A and B (n=5), were manufactured (DDDP, EvoDent). Trueness was evaluated by comparing values for 26 parameters with the CAD models' reference values and precision through standard deviation. The trueness and precision were higher for linear than for angle parameters. X- and Y-axes showed higher trueness than Z-axis and model B higher trueness than model A. The conclusions are; the accuracy is dependent on the design of the object. The linear precision appears to be high. The highest trueness was observed for a surgical guide polymer (NextDent™ SG). The definition of clinically relevant accuracy and acceptable production tolerance should be evaluated in future studies.