Background:
A major factor that affects the success of a fixed prosthesis is its fit. A proper marginal fit would prevent future biological failures of the fixed dental prosthesis. These distortions begin at the wax pattern stage itself. One of the major reasons is the manual labour involved. With the advent of CAD/CAM and 3D printed technology these errors can be reduced or avoided completely.

Aim of the study:
To evaluate marginal gap and internal gap of three-unit Co-Cr fixed dental prosthesis fabricated by patterns produced with conventional techniques and those produced by using 3D printed resins.

Material and methods:
Typhodont teeth were prepared for a metal ceramic 3-unit prosthesis. Forty-two dental stone models were fabricated. They were divided into group A (handmade wax patterns) and B (3D printed resin pattern). These were cast into Co-Cr 3-unit fixed dental prosthesis framework using lost wax technique. All the specimens were sectioned and viewed under a stereomicroscope. The marginal and internal gap were noted. The results were subjected to Shapiro Wilks test.

Results:
The results revealed that conventionally made wax patterns showed greater marginal and internal gap when compared to 3D printed pattern at both molar and premolar end.

Conclusions:
Frameworks fabricated using a CAD-CAM and 3D printed workflow had significantly smaller marginal and internal discrepancies compared to those with a traditional workflow. Both groups demonstrated marginal discrepancies within the range of clinical acceptability.