Research conducted at university to evaluate the strength of 3-element bridges molded with DWS resin compared with milled bridges.
Purpose: To evaluate the fracture resistance of three-unit fixed dental prostheses (FDPs) made of composite, high-density polymer (HDP), fiber-reinforced composite (FRC), and metal-ceramic (MC) using different fabrication methods.
Materials and Methods: A typodontic model was prepared to receive a three-element FDP to replace a missing maxillary second premolar. The prepared model was digitally scanned with an intraoral scanner (Trios3, 3Shape, Denmark).
A total of 60 FDPs were fabricated, divided into four groups (n = 15) based on materials and fabrication method: the subtractive method was used for the FRC (Trilor, Bioloren, Italy) and HDP (Ambarino, Creamed, Germany) groups; the HDP group was monolithic, while the FRC group was layered with a nanocomposite (G-aenial Sculpt, GC).
The additive method was used for the 3D printed nanocomposite (3DP) (Irix Max, DWS, Italy) and Cr-Co infrastructure (Starbond CoS 30 powder) of MC groups.
FDPs were glued onto molds made by stereolithography (SLA). All specimens were subjected to thermomechanical loading and fracture tests. Data on maximum load (N) at fracture were statistically analyzed by one-way analysis of variance (ANOVA) followed by Games-Howell post hoc test (α = 0.05).
Results: The MC group reported the highest fracture toughness with a statistically significant difference (2390.87 ± 166.28 N) compared with the other groups.
No significance was found between the 3DP and HDP groups (1360.20 ± 148.15 N and 1312.27 ± 64.40 N, respectively), while the FRC group showed the lowest value (839.07 ± 54.30 N).
The highest frequency of nonrepairable failure was observed in the MC and FRC groups, while the HDP and 3DP groups had a high frequency of repairable failure.
Conclusions: Significant differences in fracture toughness were found among the groups tested.
The load capacity of composite-based FPDs exceeded the range of maximum chewing forces.
Clinical significance: 3D printed and milled composite-based materials could offer a suitable solution for FPD fabrication.
Keywords: CAD/CAM, fiber-reinforced composite, fixed dental prosthesis, fracture toughness, high-density polymers, 3D printing.
The Journal of Contemporary Dental Practice (2021): 10.5005/jp-journals-10024-3137
Three-unit FPDs made from monolithic materials, such as 3DP composite and HDPs, showed better fracture resistance than CAD/CAM FRC layered FPDs, where chipping was the most common type of failure. 3D printed and milled composite-based materials could offer a suitable solution for the fabrication of FDPs.