Clinical Objective:

Determining the flexural strength and fracture load of printed restorations is essential for improving the durability and longevity of dental prostheses. This study examines the fracture load of 3D printed 4-unit fixed partial dentures produced according to manufacturer specifications.

Methods:

A master cast was scanned using a Trios desktop scanner and saved as an STL file. A 4-unit FPD was digitally designed with Zbrush software. Four materials were used: Sprint Ray's OnX, Crown, Ceramic Crown, and Form Lab's Permanent Crown. Ten samples of each material were printed at resolutions of 50 µm or 100 µm (OnX), then washed and post-cured. A three-point flexural test at 1 mm/min was performed on each sample, and the data were analyzed using a one-way ANOVA test.

Results:

The OnX resin group required a higher load to fracture the 4-unit FPD, outperforming other resins by withstanding greater internal stress before failure. Statistical differences in stress and load were observed among all resin groups compared.

Conclusion:

The OnX resin group exhibited a higher load to fracture for the 4-unit FPD among the tested ceramic-impregnated resin printable restorative materials. Understanding how different resins perform under load and stress helps clinicians select the best materials for improved longevity.