Effect of connector cross-sectional area on fracture strength of maxillary anterior provisional fixed partial dentures fabricated using CAD/CAM

Background Provisional fixed partial dentures (PFPDs) are widely used during fixed prosthodontic treatment; however, the effect of fabrication method and connector cross-sectional area on their fracture resistance remain unclear. Methods Three fabrication methods were investigated: additive manufacturing (three-dimensional [3D]), subtractive manufacturing (milled [Mi]), and the conventional method (CM). Connector cross-sectional areas of 9.0, 12.0, and 15.0 mm² were designed, and five specimens were fabricated for each condition (n = 5). Each PFPDs was temporarily cemented onto a test model and subjected to fracture testing using a universal testing machine. The fracture mode was visually examined. The fracture load data obtained from the universal testing machine were analyzed using two-way analysis of variance (ANOVA) followed by Bonferroni post hoc tests (α = 0.05). Results The mean fracture loads (N) at connector cross-sectional areas of 9.0, 12.0, and 15.0 mm² were 295 ± 33, 425 ± 37, and 590 ± 42 for the 3D group; 218 ± 24, 265 ± 41, and 400 ± 52 for the Mi group; and 177 ± 37, 211 ± 31, and 255 ± 18 for the CM group, respectively. Two-way ANOVA revealed significant main effects of both fabrication method and connector cross-sectional area, along with a significant interaction between the two factors (p < 0.05). Conclusions In maxillary anterior three-unit PFPDs fabricated using each manufacturing method, the fracture load increased with increasing connector cross-sectional area.