The patients will be taught in the intervention visit and instructed to use the same 1 inch amount of the two toothpastes, mix them and apply it on a soft bristle toothbrushes with the same brushing technique they for 2 minutes twice a day (morning and last thing at night) along the study period without further rinsing, only spitting of the excess material.

The tooth will be dried, and cotton roll isolated. According to manufacturer instructions, thin coat of the varnish will be applied on the teeth for 10 - 20 s using a microbrush in a horizontal sweeping motion , then drying with air will be done. Patients will be instructed to avoid food and liquid intake for two hours after varnish application also, to use conventional 1425 ppm fluoride toothpaste at home with the same instructions mentioned before.

The patients will be taught in the intervention visit and instructed to use the same 1 inch amount of the toothpaste and soft bristle toothbrushes with the same brushing technique they for 2 minutes twice a day (morning and last thing at night) along the study period without further rinsing, only spitting of the excess material.

Administration ofa toothpaste

DIAGNOdent calibration will be performed first then the tip of the probe will be positioned on the lesion and rotated around its vertical axis until the highest value will be reached and a peak reading will be recorded

The tooth will be visually examined according to the ICDAS scale as follows: "Code 0: Sound tooth surface: There should be no evidence of caries.

Code 1: First visual change in enamel: When seen wet there is no evidence of any change in color attributable to carious activity, but after prolonged air drying a carious opacity (white or brown lesion) is visible that is not consistent with the clinical appearance of sound enamel.

Code 2: Distinct visual change in enamel when viewed wet: There is a carious opacity or discoloration (white or brown lesion) that is not consistent with the clinical appearance of sound enamel. This lesion may be seen directly when viewed from the buccal or lingual direction. In addition, when viewed from the occlusal direction, this opacity or discoloration may be seen as a shadow confined to enamel, seen through the marginal ridge.

Code 3: Initial breakdown in enamel due to caries with no visible dentin: Once dried for approximately five seconds there is disti