Table 4. Data extraction of studies using compositional gradients.

S. No	Author and year	Journal	Country	Material Characteristics	Properties evaluated	Results
1.	Tsukada 2014⁶⁷	Journal of Dentistry	Japan	Zirconia-Porcelain Yttria-stabilized tetragonal zirconia (Y-TZ) powder-High Fusing Porcelain Y-TZP/porcelain volume fractions were as follows: 100/ 0 90/10 80/20 70/30 0/100	Three-point bending test, density, thermal stress estimation, Weibull analysis, Young’s modulus, coefficient of thermal expansion.	Graded structure effectively increased the bending strength of Y-TZP/porcelain-composite materials.
2.	Maqtari 2014⁶⁸	Dental Materials Journal	Malaysia	Varied compositions were estimated by applying the “rule of mixture” (ROM) for the following: Zirconia (100%) without Alumina, Zirconia (80%) + Alumina (20%) Zirconia (60%) +Alumina (40%), Zirconia (50%) +Alumina (50%) First layer consisting of Zirconia (100%) (without Alumina) with Second Layer of Zirconia (80%) +Alumina (20%) First layer consisting of Zirconia (100%) (without Alumina) with a Second Layer of Zirconia (60%) +Alumina (40%) First layer of Zirconia (100%) (without Alumina) with Second Layer of Zirconia (50%)+Alumina (50%)	Stress distribution using Finite element analysis	von Mises stress, tensile stress, and compressive stress in functionally graded structures were reduced.Reduced shear stress were observed in functionally graded veneer-core-cement-dentin interfaces.
3.	Madeira 2019⁶⁹	Journal of the Mechanical Behaviour of Biomedical Materials	Portugal Brazil	Zirconia-porcelain Yttria-stabilized tetragonal zirconia (Y-TZ) powder-Dental Porcelain Y-TZP/porcelain volume (%) fractions were of 0/100, 20/80, 40/60, 60/40, 80/20 and 100/0.	Damping capacity, dynamic Young’s modulus, microhardness, dynamic mechanical analysis	Increased damping capacity was exhibited by porcelain matrix composites, whereas a higher dynamic modulus was exhibited by zirconia-rich composites.
4.	Suteja 2023⁷⁰	Dental Materials	Korea	Cerium-Porcelain and Yttrium aluminum garnet cerium (YAG-Ce)-Feldspathic Porcelain (FP). Y-FP layers (volume %) with shade from bottom to top of 180 layers (0/100), Yellow 140 layers (25/75), decreasing yellow 100 layers (50/50), decreasing yellow 90 layers (75/25), slightly whiter 70 layers and (100/0) slightly whiter.	Slurry viscosity, flowability, UV sensitivity, curing penetration, density, shrinkage; CIE lab color difference and flexural strength	Functionally graded additive manufacturing (FGAM) technique successfully reproduced color gradation by manipulating the composition shift of FP and YAG:Ce. This result underscores the potential of FGAM as a promising alternative for producing dental prosthetics with improved esthetic appeal.