Evaluation of the Mechanical Properties of Provisional 3D-Printed Resin After Repair with Different Materials: An In Vitro Study.

Purpose: To evaluate the mechanical properties of the 3D-printed provisional restoration material after it was repaired using different materials.

Materials and methods: Bar specimens were manufactured using 3D-printing technology in accordance with the ISO 10477:2020 standards and divided into five groups randomly. For repair material application and replacement on the standardized silicone mold, the test specimens were ground at the center by 1 × 2 × 2 mm. No grinding was done on the control group specimens. Flowable composite, bis-acryl composite resin, polymethyl methacrylate resin, and temporary 3D-printing resin were used as repair materials (n = 16). The specimens underwent a three-point bending (3PB) test with a crosshead speed of 1 mm/minute to assess their flexural strength (FS) and flexural modulus (FM). The data received statistical analysis with one-way ANOVA and Tukey test. Weibull analysis was performed, and the Weibull modulus of the specimens was calculated.

Results: Control group specimens showed the highest FS (142 ± 12.6 MPa) and FM (4,497 ± 1,205 MPa) values. Among the test groups, the use of temporary 3D-printing resin as a repair material exhibited the greatest FS (67 ± 33.3 MPa) values and showed statistical significance when compared to all other groups.

Conclusions: Repairing 3D-printed provisional resin material weakens its mechanical properties. However, using the original 3D-printed provisional resin material can be an effective choice for implementing minor modifications and additions.