Wear, fracture strength, and reliability of three-unit definitive fixed dental prostheses fabricated with different vat polymerization methods.

OBJECTIVES

To compare the wear, fracture strength, and reliability of definitive resin three-unit fixed dental prostheses (FDPs) additively manufactured (AM) with different technologies to those subtractively manufactured (SM) from a high-impact polymer composite (HIPC).

METHODS

Thirty-two three-unit posterior FDPs (1-mm chamfer finish line, connector cross-sectional area: 16 mm2, minimum occlusal thickness: 1 mm, cement space: 100 µm) were either AM from a resin for definitive use (VarseoSmile Triniq) using digital light processing (AM-DLP), low force display (AM-LFD), or liquid crystal display (AM-LCD) technologies, or SM from a HIPC (SM-HIPC) (n = 8). All FDPs replaced the right second premolar. All FDPs were scanned before and after thermomechanical aging and subjected to load-to-fracture testing. Pre- and post-aging scans were digitally assessed for maximum wear depth and volume loss. Wear and fracture data were analyzed using one-way analysis of variance and Tukey tests, while chi-squared tests were used to evaluate Weibull parameters (α = 0.05).

RESULTS

Mean fracture loads ranged from 1013 to 2725 N, while mean characteristic strength values ranged from 1072 to 2895 N. SM-HIPC mostly had lower wear (P ≤ 0.018), and AM-DLP had lower volume loss than AM-LFD and AM-LCD (P < 0.001). SM-HIPC showed the highest fracture load and characteristic strength, while AM-LFD had higher fracture load and characteristic strength than AM-LCD (P ≤ 0.001).

CONCLUSIONS

SM-HIPC demonstrated better wear resistance along with the highest fracture and characteristic strength. Among AM FDPs, AM-DLP showed the lowest volume loss, while AM-LFD withstood higher loads and exhibited greater characteristic strength than AM-LCD.

CLINICAL SIGNIFICANCE: Three-unit FDPs fabricated with tested AM resin and digital light processing or low force display technologies may be suitable alternatives to those in high-impact polymer composite considering the reported masticatory forces of the molar region (1110 N). Nevertheless, they might also be more prone to complications related to wear.