Mechanical Properties of 3D Printing Resin in Dentistry - XDENT LAB

In recent years, 3D printing resin has become a key material in digital dentistry. Its ability to produce highly accurate geometries, combined with fast manufacturing and consistent material quality, makes it suitable for dental models, surgical guides, temporary restorations, splints, and try-in prostheses.

To ensure predictable clinical performance, it is essential to understand the mechanical properties of 3D printing resin - how the material behaves under different types of forces encountered in the oral environment.

1. Tensile Strength

Tensile strength refers to the maximum stress a material can withstand when being stretched or pulled before it fractures.

For dental 3D printing resin, the tensile strength is approximately 106 MPa, indicating good resistance to tensile forces.

👉 Clinical significance:

• Helps prevent cracking or breakage during insertion and removal
• Ensures structural integrity in thin or delicate areas
• Suitable for temporary crowns, splints, and try-in frameworks where tensile forces may occur

2. Tensile Modulus

Tensile modulus (also known as Young’s modulus) measures a material’s stiffness, or its resistance to elastic deformation under tensile load.

With a tensile modulus of around 13,200 MPa, this resin exhibits relatively high rigidity.

👉 Clinical relevance:

• Limits elastic deformation under functional loads
• Maintains dimensional accuracy over time
• Critical for dental models, surgical guides, and precision-based applications

3. Elongation at Break

Elongation at break describes how much a material can stretch, expressed as a percentage of its original length, before it breaks.

This property reflects the material’s ductility.

An elongation at break of up to 186% indicates that the resin can undergo significant deformation before failure.

👉 Why this matters:

• Reduces brittleness compared to conventional rigid polymers
• Allows better absorption of stress and sudden loads
• Minimizes the risk of catastrophic fracture during clinical handling or intraoral use

4. Flexural Strength

Flexural strength measures a material’s ability to resist deformation and fracture when subjected to bending forces, which are common during mastication.

The resin demonstrates a flexural strength of approximately 190 MPa, indicating strong resistance to bending.

👉 Practical applications:

• Temporary restorations
• Diagnostic prostheses
• Try-in frameworks exposed to indirect occlusal forces

5. Flexural Modulus

Flexural modulus represents a material’s stiffness under bending loads, reflecting how much it flexes when force is applied.

With a flexural modulus of around 11,880 MPa, the resin achieves a balance between rigidity and flexibility.

👉 Clinical implications:

• Prevents excessive bending under occlusal stress
• Avoids over-rigidity that may cause discomfort
• Supports stable, comfortable short- to medium-term restorations

6. Izod Impact Strength

Izod impact strength evaluates a material’s resistance to sudden impact or shock loading, such as dropping or accidental collision.

An Izod impact strength of approximately 51 J/m indicates moderate impact resistance.

👉 Benefits in practice:

• Reduces breakage during handling, adjustment, or transportation
• Improves durability in daily laboratory workflows
• Enhances overall reliability of 3D printed dental components

7. Heat Deflection Temperature (HDT)

Heat Deflection Temperature (HDT) is the temperature at which a material begins to deform under a specified load. It reflects thermal stability under mechanical stress.

• HDT @ 1.8 MPa: 111°C
• HDT @ 0.45 MPa: 286°C

👉 Clinical importance:

• Ensures shape stability during sterilization and post-processing
• Minimizes thermal distortion
• Suitable for dental applications involving elevated temperatures

Conclusion

Overall, dental 3D printing resin exhibits a well-balanced combination of strength, stiffness, ductility, impact resistance, and thermal stability. These mechanical properties enable the material to meet the functional demands of the oral environment while maintaining accuracy and safety.

Selecting the appropriate resin based on its mechanical behavior is essential for achieving predictable outcomes, long-term performance, and patient satisfaction in digital dentistry.

References

1. ISO 4049 – Dentistry — Polymer-based restorative materials
2. ISO 20795-1 – Dentistry — Base polymers — Denture base polymers
3. ASTM D638 – Standard Test Method for Tensile Properties of Plastics
4. ASTM D790 – Standard Test Methods for Flexural Properties of Unreinforced and Reinforced Plastics
5. Revilla-León, M. et al. Additive Manufacturing Technologies Used for Processing Polymers: Current Status and Potential Application in Prosthetic Dentistry. Journal of Prosthodontics.
6. Stansbury, J.W., Idacavage, M.J. 3D printing with polymers: Challenges among expanding options and opportunities. Dental Materials.