Purpose :The purpose of this in-vivo study was to investigate the remineralizing effects of natural (propolis, hesperidin) versus synthetic agent (silver diamine fluoride with potassium iodide) after treatment of deep carious dentin at different time intervals. Materials and methods: Patients with deep carious class I lesions were selected according to inclusion and exclusion criteria. Class I carious lesions were randomly distributed into 4 groups according to treatment material: 1. Propolis, 2. Hesperidin, 3.Silver diamine fluoride with potassium iodide (SDF+KI), and 4. Control group (no treatment). Class I cavities were all prepared using step-wise caries removal technique. The treatment materials were then applied on the remaining carious dentin and restored with a glass ionomer (GIC) restoration. Assessment of remineralization was done by measurement of mineral-density of dentin using digital x-ray machine at baseline, 6-weeks and 12-weeks time intervals. Results: Silver diamine fluoride had a higher significant remineralizing effect than control, propolis or hesperidin. While propolis had a higher significant remineralizing effect than hesperidin. Conclusions: Both silver diamine fluoride and propolis agents have remarkable effect on remineralization of carious dental tissues.