Effect of pattern fabrication methods on retentive strength in three-unit implant-supported frameworks: A comparative analysis

Abstract

Abstract Objective Given the significant role of retention in the long-term success of implant-supported prostheses, this study aimed to compare the retentive strength of three-unit implant-supported frameworks manufactured using the conventional, subtractive milling, and 3D printing methods. Methods In this in-vitro study, two fixture analogs were placed in the mandibular right first premolar and first molar region of a Dentiform model, and two prefabricated abutments were secured in the fixture analogs. A total of 27 three-unit frameworks were fabricated utilizing wax patterns prepared through conventional, milling, and 3D printing techniques (n = 9 per group). The frameworks were cemented with zinc oxide eugenol and subjected to thermocycling. The retentive strength of each specimen was evaluated through a pull-out test conducted with a universal testing machine. The data were analyzed using one-way ANOVA and Tukey’s post hoc test (P < 0.05). Results The three groups were found to be significantly different (P = 0.01). While the 3D printing and milling groups were not significantly different (P = 0.99), they yielded significantly higher retentive strength compare to the conventional group (P = 0.02 for 3D printing and P = 0.03 for milling group). Conclusion The utilization of 3D printing and milling technique for wax pattern preparation significantly increased the retention of the implant-supported framework, with no statistically significant difference between the two methods.