Complete denture wearers with knife edge ridge often experience pain and discomfort. This condition is a result of the pressure beneath the complete denture over the physiological and mechanical capacity of the alveolar ridge. Soft denture reline (SDL) is one of the treatments to relieve pain, thereby improving the patient’s comfort due to cushioning effect and reducing the stress on supporting tissue by distributing occlusal load in the alveolar ridge. The thickness of the reline material influences the stress distribution. Finite Element Analysis (FEA) allows simulation of the complex biomechanical conditions of the denture over the thin mucosa, thereby allowing the assessment of stress distribution in the superficial mucosa and alveolar ridge. This literature review aims to analyze the stress distribution in the knife edge ridge beneath the complete denture with autopolymerized SDL acrylic-based and SDL silicon-based with different thicknesses. Autopolymerized soft denture liners are widely chosen because they can be applied in a chairside one visit. Based on research using FEA, an SDL thickness of 2 mm can decrease the stress in the mucosa and the underlying bone. In contrast, according to Parr and Rueggberg, the ideal thickness of SDL is 2-3 mm. Lima et al stated that an SDL thickness of 2.5 mm showed a slightly higher level of stress. Silicone liner showed a lower amount of stress on the mucosa and alveolar ridge than the acrylic liner, despite the use of 2 mm SDL being the ideal thickness for distributing stress optimally and relieving pain.