The fluoride varnish applications will be applied with identical intensive protocols every 2 weeks for 6 weeks. The application of will be according to manufacturer's instructions.

For primary dentition, the modified version of the OHI-S by Miglani et al will be used, it is divided into two scores debris index and calculus index only the debris index will be used in which the index teeth are: The buccal surface of maxillary right second molar (tooth 55), The buccal surface of the maxillary right central incisor (tooth 51), The buccal surface maxillary left second molar (tooth 65), The lingual surface of the mandibular left second molar (tooth 75),The buccal surface of the mandibular left central incisor (tooth 71),The lingual surface of the mandibular right second molar (tooth 85). Each surface will take a score from 0-3. The scores of the involved surfaces will be totaled and divided by the number of teeth scored to get the index value.

Using a dental light reflector, visual inspection of all tooth surfaces for WSLs will be undertaken, with wet tooth surfaces and again after 5 seconds of drying with a gentle air stream. Each lesion will be scored according to ICDAS II criteria for severity, selecting only lesions scored as 1, 2 or 3.

Using a dental light reflector, visual inspection of all tooth surfaces for WSLs will be undertaken, with wet tooth surfaces and again after 5 seconds of drying with a gentle air stream. Each lesion will be scored according to ICDAS II criteria for severity, selecting only lesions scored as 1, 2 or 3.

Using a dental light reflector, visual inspection of all tooth surfaces for WSLs will be undertaken, with wet tooth surfaces and again after 5 seconds of drying with a gentle air stream. Each lesion will be scored according to ICDAS II criteria for severity, selecting only lesions scored as 1, 2 or 3.

Using a dental light reflector, visual inspection of all tooth surfaces for WSLs will be undertaken, with wet tooth surfaces and again after 5 seconds of drying with a gentle air stream. Each lesion will be scored according to ICDAS II criteria for severity, selecting only lesions scored as 1, 2 or 3.

Probe B OF Laser fluorescence (LF) examination for each lesion will be performed using DIAGNOdent. It operates with a diode laser having a wavelength of 655 nm and 1 mW peak power. Sound enamel does not fluoresce at this wavelength, but caries and bacteria do. The instrument is calibrated according to manufacturer's instructions. A baseline zero value for each patient is obtained by choosing a clear non carious patch of enamel usually middle third of an anterior tooth. By pointing the pen perpendicular to this area and touching the set button for 2 seconds until set 0 appears, the button is then released. Zero baseline value has been set. Under cotton roll isolation and after air drying with an air syringe, the DIAGNOdent probe will be placed perpendicular to the test site and rotated along the lesion to scan the area completely. Three measurements of each lesion will be taken and averaged to give the final score.

Probe B OF Laser fluorescence (LF) examination for each lesion will be performed using DIAGNOdent. It operates with a diode laser having a wavelength of 655 nm and 1 mW peak power. Sound enamel does not fluoresce at this wavelength, but caries and bacteria do. The instrument is calibrated according to manufacturer's instructions. A baseline zero value for each patient is obtained by choosing a clear non carious patch of enamel usually middle third of an anterior tooth. By pointing the pen perpendicular to this area and touching the set button for 2 seconds until set 0 appears, the button is then released. Zero baseline value has been set. Under cotton roll isolation and after air drying with an air syringe, the DIAGNOdent probe will be placed perpendicular to the test site and rotated along the lesion to scan the area completely. Three measurements of each lesion will be taken and averaged to give the final score.

Probe B OF Laser fluorescence (LF) examination for each lesion will be performed using DIAGNOdent. It operates with a diode laser having a wavelength of 655 nm and 1 mW peak power. Sound enamel does not fluoresce at this wavelength, but caries and bacteria do. The instrument is calibrated according to manufacturer's instructions. A baseline zero value for each patient is obtained by choosing a clear non carious patch of enamel usually middle third of an anterior tooth. By pointing the pen perpendicular to this area and touching the set button for 2 seconds until set 0 appears, the button is then released. Zero baseline value has been set. Under cotton roll isolation and after air drying with an air syringe, the DIAGNOdent probe will be placed perpendicular to the test site and rotated along the lesion to scan the area completely. Three measurements of each lesion will be taken and averaged to give the final score.

Probe B OF Laser fluorescence (LF) examination for each lesion will be performed using DIAGNOdent. It operates with a diode laser having a wavelength of 655 nm and 1 mW peak power. Sound enamel does not fluoresce at this wavelength, but caries and bacteria do. The instrument is calibrated according to manufacturer's instructions. A baseline zero value for each patient is obtained by choosing a clear non carious patch of enamel usually middle third of an anterior tooth. By pointing the pen perpendicular to this area and touching the set button for 2 seconds until set 0 appears, the button is then released. Zero baseline value has been set. Under cotton roll isolation and after air drying with an air syringe, the DIAGNOdent probe will be placed perpendicular to the test site and rotated along the lesion to scan the area completely. Three measurements of each lesion will be taken and averaged to give the final score.