Evaluation of Fabrication Technique on the Marginal Fit and Fracture Resistance of an Interim Bridge: An In Vitro Study.

AIM: To compare computer-aided design/computer-aided manufacturing (CAD/CAM) and 3D-printing fabrication techniques of an interim bridge on marginal fit and fracture resistance.

MATERIALS AND

METHODS

Thirty bridges were divided into two groups according to fabrication technique: Group I (n = 15) by CAD/CAM milling and group II (n = 15) by 3D-printing technology. A typodont model, with the first maxillary molar and premolar, and a missing second premolar, was selected for this study. The prepared master model was digitally scanned. The scans were exported to obtain the final virtual 3D master model, which was then used to fabricate the test models and to design and fabricate the provisional dental prosthesis using CAD/CAM technology (milling and printing). The vertical marginal gap was measured. All groups were subjected to thermocycling, and then the marginal gap was remeasured to analyze the influence of thermomechanical aging on the marginal gap. Then the specimens were loaded for the fracture resistance test.

RESULTS

The 3D-printed group demonstrated a higher mean marginal gap compared to the milled group before and after thermocycling. While specific combinations of procedure, surface, and tooth type were affected by thermocycling. For the fracture resistance, the milled group demonstrated substantially higher fracture resistance than the 3D-printed group.

CONCLUSION

The CAD/CAM-milled restoration showed better marginal fit and higher fracture resistance than the 3D-printed restoration in temporary prosthesis, but both groups were within clinically acceptable limits. The thermocycling aging influenced the marginal fit of interim fixed bridges.

CLINICAL SIGNIFICANCE: This study demonstrates that the fabrication technique and thermocycling impact the marginal fit and fracture resistance of interim bridges. The milling technique provides superior marginal fit and fracture resistance; therefore, it is recommended that clinicians prioritize the milling technique to enhance longevity and stability of dental prostheses.