An In-Vitro Study to Assess the Effect on Flexural Strength of Two Different Ceramic-Veneered Sub-Structures with Four Variable Thickness

Abstract

Background:  Esthetic dentistry combines technical skill and artistic creativity to produce dental prostheses that restore function and enhance smiles. Over the years, dental materials have evolved from amalgams and gold alloys to advanced ceramics like zirconia, which offer superior aesthetics and strength. Porcelain-Fused-to-Metal (PFM) restorations, used since 1965, are durable but can compromise aesthetics due to light transmission issues. Zirconia ceramics, ideal for anterior and posterior restorations, combine strength and translucency similar to natural teeth. Advances in CAD/CAM and laser sintering technologies have improved the precision and durability of zirconia crowns. Understanding flexural strength, a material’s resistance to deformation, is crucial for durable and aesthetically pleasing restorations.

This study examined the flexural strength of two different ceramic-veneered sub-structures with varying thicknesses, promoting the shift from PFM to Porcelain-Fused-to-Zirconia. The findings highlight improved mechanical performance, enhancing both the aesthetic value and overall well-being of patients.

Materials and Method:  An In-Vitro study in which 80 samples were fabricated and divided equally into two groups, i.e., Metal and Zirconia Group. These two groups were further divided into four sub-groups of different thickness, i.e., 0.5mm, 0.7mm, 0.9mm and 1.2mm containing 10 samples in each sub-group. The Metal and Zirconia samples were fabricated using the Conventional Wax-Burnout and Computer-Assisted Milling Technique respectively. The thickness of the samples was later verified using a vernier calliper, followed by uniform layering of 1mm with porcelain of all the samples with the help of a silicone jig. The samples were later subjected to 3-Point Flexural Test in the Universal Testing Machine and the values of the flexural strength were obtained.

Results: The study revealed that the flexural strength of the core structures of various thickness kept increasing with an increase in the thickness. However, Group 1, i.e., Metal group values were significantly higher on comparison to its counterpart, i.e., Zirconia group of the same thickness.

Conclusion: These findings highlight the significance of thickness while fabrication of core structure in order to increase the overall functionality and aesthetics for the patient’s well-being.