Effect of Cement Type and Thickness at the Marginal Area on Stress Distribution in Monolithic Zirconia Crowns: A Finite Element Analysis

Background: Monolithic zirconia crowns are used for restoring aesthetics and function in the dentition. However, the stress distribution pattern in these crowns remains relatively understudied. This study aimed to investigate the effect of cement thickness and type in the margin area and 1 mm above the finish line on the stress distribution pattern in monolithic zirconia crowns.Methods and Materials: Sixteen finite element models were made using Mimics Medical and SolidWorks software. The models simulated a human premolar tooth that was restored with a monolithic zirconia crown. Models differed according to the utilized cement (zinc phosphate, Panavia, Glass ionomer, and RelyX) and the cement thickness at the marginal area. Each model was subjected to a force of 100 N applied at a 45º angle. Finite element analysis was performed using Abaqus software, and the stress distribution and concentration areas were determined.Results: Finite element analysis results showed that the highest stress of cement occurred when cement was present in the margin area, while the lowest stress was observed when no cement was used in this area. Zinc phosphate cement exhibited the highest tensile stress, whereas RelyX showed the least. As the elastic modulus of the cement decreased, the stress in the crown increased.Conclusion: In monolithic zirconia crowns, when no cement is present at the margin, the lowest stress is concentrated in the cement, and the highest stress is concentrated in the crown. RelyX cement accumulates the least stress within itself, leading to higher stress concentration in the crown, whereas zinc phosphate cement absorbs the highest stress and results in the least stress concentration in the crown.