Objectives: This study was done to compare between the effectiveness of using highly filled and lightly filled sealants in preventing demineralization and resisting acid and abrasion through assessing enamel color change differences and sealant retention after induced challenges. Methods: 100 human premolars were collected and allocated into 2 groups. The buccal surfaces of the 1st group were sealed with a 38% filled sealant (Opal®SealTM) and the 2nd group with an 18 % filled one (PRO SEAL®). Both groups were exposed to acidic and abrasive challenges. Enamel color changes were recorded spectrophotometrically at baseline (T0), after sealant application (T1), after first exposure to acidic challenge (T2), and after second exposure to acidic challenge and simulated toothbrushing (T3). Standardized photographs were taken for each tooth under ultraviolet light at baseline and at (T3). Teeth images were analyzed using computer software to estimate sealant coverage and fluorescence loss. Results: The best protection was seen in the Opal seal group after the 1st acidic challenge (p=0.000) when compared with PRO SEAL. Greater sealant material loss (68.78% ± 15.54) and fluorescence loss (82.46% ± 11.04) were seen in the PRO SEAL group (p=0.000). Both sealants changed the original enamel color similarly and exceeded the clinically detectable threshold (ΔE=3.7). Conclusion: Based on the results of this study; increasing the filler content strengthens the sealant, therefore, offering more protection against white spot lesions. Both sealants degrade with increasing the challenges. Both sealants change the initial enamel color similarly.