Intervention
tooth
Participants in the first group received P11-4 (Curodont Repair™, Biomedical products for tooth preservation) only at baseline. First, the tooth was completely isolated using rubber dam followed by cleaning of the tooth surface with sodium hypochlorite 2% for 20 s, acid etching with phosphoric acid gel 35–37% for 20 s, rinsing and drying. The agent was applied by removing the safety clip, activating the applicator and squeezing out the sponge above the lesion and the solution was left to diffuse for 5 min [In the second group, each tooth received two drops of NSF only at baseline. NSF was prepared at the Faculty of Pharmacy, Alexandria University according to Wei et al. method [The third group received 5% NaF varnish (Duraflor®) at baseline and after 6 months. The teeth were dried and a very thin coat of the varnish was applied and allowed to dry for 10 s [All participants were instructed to eat only soft foods and avoid hot liquids for two hours. Oral health instructions were given to all participants.