A comparative evaluation of Vat-photopolymerization and PolyJet 3D printers using multiple measurement methods

Area of Science:

• Additive Manufacturing
• Biomaterials
• Dental Technology

Background:

• Additive manufacturing (AM) is increasingly used in dentistry, making dimensional accuracy crucial for restorations.
• Inaccurate AM components can negatively impact restoration fit, function, and longevity.
• Precise measurement protocols are essential for predictable clinical outcomes in dental AM.

Purpose of the Study:

• To evaluate the 3D deviations of dental restorations fabricated using Stereolithography (SLA), mask Stereolithography (mSLA), and PolyJet technologies.
• To compare the accuracy of three distinct measurement methodologies: digital micrometer, micro-computed tomography (micro-CT), and optical scanning.
• To identify the most accurate 3D printing technology and measurement method for dental applications.

Main Methods:

• Sixty 15 mm cube specimens were printed using four printers (Form 3B+, Prusa SL1, Objet 30 Orthodesk, Connex 260).
• Dimensional accuracy was assessed using a digital micrometer, micro-CT, and an optical scanner at twelve locations.
• Statistical analysis was performed to compare deviations across printers and measurement methods.

Main Results:

• Micro-CT and micrometer measurements provided reliable dimensional data; optical scanning underestimated values.
• Micro-CT offered superior surface topography definition.
• Significant deviations from the 15 mm nominal value were observed with micro-CT across X, Y, and Z axes, with higher deviations in X and Y compared to Z.

Conclusions:

• Micro-computed tomography (micro-CT) is the most precise measurement method for evaluating 3D printed dental components.
• The Connex260 printer demonstrated the lowest dimensional deviation, indicating superior performance among the tested devices.
• Optimal accuracy was consistently achieved along the Z-axis across all tested 3D printing technologies.