Scientific Studies on

VarseoSmile Crown plus

Breaking Load and Abrasion Resistance

Purpose

In this study the long-term (10-year) performance of 3D printed crowns made of VarseoSmile Crown plus was studied, with a focus on the breaking load and abrasion behaviour.

Material and methods

3D printed crowns made of VarseoSmile Crown plus, and crowns made of the manually-layered material Sinfony* (Fa. 3M*), were tested under the same conditions for comparison purposes. Sinfony was chosen as the comparison material because it is a hybrid material that has been well-established in the market and has demonstrated the highest abrasion resistance to date in scientific studies [1]. The crowns were affixed onto milled stumps made of Trinia* (by Bicon*, modulus of elasticity of the stump material conforms to the 18.8 GPa of natural dentin), using Variolink Esthetic DC* (by Ivoclar Vivadent*).

The breaking load for both materials was determined using a series of 8 crowns in each case, measuring both before and after a simulated in-vivo 10-year masticatory load (2.4 million chewing cycles at a load of 50 N and a lateral motion of 0.7 mm with simultaneous thermocycling of 12,000 cycles of between 5 and 55 °C). Steatite, a magnesium silicate with properties similar to enamel, was used as antagonist material. Measurement of the breaking load was performed via a compression test in a universal testing machine. For this purpose, the respective test specimen was placed in the testing device and loaded with a test die (ball ø 6 mm) onto the middle of the crown, until breakage. The abrasion following the lateral motion was determined by comparing the digital 3D scans of the occlusal surfaces both before and after the chewing simulation.

Results

The breaking loads for the VarseoSmile Crown plus crowns exhibited an initial average value of 1,936 N before the chewing simulation. This average value did not change after the chewing simulation. Thus, no detectable material fatigue took place. With an average breaking load of 1,740 N, the comparison product Sinfony exhibited a lower maximum value before the chewing simulation, as compared to VarseoSmile Crown plus. After the simulation, this value decreased to 1,337 N due to material fatigue.

The material wear was measured on the basis of the change in height profile of the crowns, and totalled 0.275 mm after simulation of the 10-year in-vivo masticatory load for the crowns made of VarseoSmile Crown plus. It is thus about 7 % lower than the material wear of 0.296 mm for the Sinfony crowns.

Conclusion

The present tests demonstrate that crowns made of VarseoSmile Crown plus achieve breaking loads that are more than two times higher than the maximum average human masticatory forces of 720 N [2], both initially as well as after a 10-year chewing simulation.

In terms of abrasion resistance, VarseoSmile Crown plus demonstrated less material loss (higher resistance to wear) after the chewing simulation than the material Sinfony.
Restorations are thus preserved for a long period of time and there is very low risk that a crown could fracture in the patient’s mouth.


Breaking loads for crowns made of VarseoSmile Crown plus (BEGO) and Sinfony (3M), before and after a 10-year chewing simulation


Source

The above information is based on a scientific study on breaking load and abrasion resistance of VarseoSmile Crown plus conducted by:

Eva Jerman, M.Sc., Marlis Eichberger, Lisa Schönhoff, B.Sc., Dr. Marcel Reymus, Prof. Dr. Dipl.-Ing. (FH) Bogna Stawarczyk, M.Sc. (2020): Fracture load and two-body wear of 3D printed and conventionally fabricated crowns: artificial aging of 10 in-vivo years, Department of Prosthetic Denistry, University Hospital, LMU Munich, Germany


[1] Bogna Stawarczyk, Roger Egli, Malgorzata Roos, Mutlu Özcan, Christoph H.F. Hämmerle (2011): The impact of in vitro aging on the mechanical and optical properties of indirect veneering composite resin, in: Journal of Prosthetic Dentistry, Vol. 106, Nr. 6, P. 386 – 398

[2] Charles H. Gibbs, Kenneth J. Anusavice, Henry M. Young, Jack S. Jones, Josephine F. Esquivel-Upshaw (2002): Maximum clenching force of patients with moderate loss of posterior tooth support: A pilot study, in: Journal of Prosthetic Dentistry, Vol. 88, Nr. 5, P. 498 – 502

* This symbol is a commercial designation/registered trademark of a company which is not part of the BEGO company group.