Subjects will be assigned to one of the three study groups using a computer generated randomization list. The recruitment of the patients will be performed by one investigator. All the measurements at the baseline and follow ups will be performed by the second investigator. Patient, the operator (until the gel will be handed over by the dental assistant), the investigator who is taking the measurement and the statistician will be blinded about the intervention groups. This will be ensured by giving codes to the intervention groups only known to the principal investigator who is not involved in the measurement and interaction with the patient.